Bi-fluid actuator

Abstract
The invention is a bi-fluid actuator for precise bi-directional movement and positioning of a mechanical object or load. The bi-fluid actuator includes a pneumatic fluid container defining opposed first and second pneumatic fluid chambers, and having a first mechanical object secured between the chambers; a hydraulic fluid container defining opposed first and second hydraulic fluid chambers, and having a second mechanical object secured between the first and second hydraulic chambers; a pneumatic fluid controller; and, a hydraulic fluid controller. Directing pneumatic fluid into either the first or second pneumatic chambers, while controlling flow of hydraulic fluid between the first and second hydraulic chambers, controls movement and positioning of the mechanical objects which may be secured to a load.
Description




TECHNICAL FIELD




The present invention relates to apparatus for accurate movement and positioning of a load, and in particular relates to a bi-fluid actuator for usage in accurately moving and positioning a load appropriately for use in automated movement, assembly manufacturing, related robotics tasks, and other industries requiring precise motion control.




BACKGROUND OF THE INVENTION




Actuators are well known in automated assembly and related tasks that utilize pneumatic, mechanical or hydraulic positioning systems. For example, it is well known to utilize an actuator to move a load carriage in repetitive movements in assembly-line manufacturing. Typical actuators include rod actuators, wherein a piston within a hollow container variably moves a rod extending out of the container back and forth between desired positions, and a load or load carriage is secured to the rod. A rodless actuator includes a sliding piston within a hollow elongate container such as a cylinder, wherein the piston is secured mechanically or magnetically to a load carriage secured to a rail or support adjacent to the hollow object so that movement of the piston moves the load carriage.




Such actuators are often powered by hydraulic fluid utilizing a controller that pumps the fluid to a chamber on a first or an opposed second side of the piston, and that also permits movement of the hydraulic fluid out of the chamber into which the piston is to be moved. Such controllers also serve to detect the position of the piston, and stop movement when the piston and linked load carriage have achieved a desired position. Hydraulic actuators provide for precision of a rate of movement and positioning of the load, however they also have substantial drawbacks associated with a necessity of pumping a hydraulic fluid that is typically freeze and boiling resistant and hence is also often a hazardous waste, along with problems of the substantial cost, complexity and service requirements of pressurized hydraulic cylinders, seals, accumulators, by-pass valves, connecting lines to and from controllers, etc. Some actuators are electro-mechanically powered with electric motors, servo motors, threaded shafts, ball screws, toothed belts, etc. They also involve substantial cost in manufacture, substantial difficulties in accurate, rapid positioning of loads, and quite significant care and service requirements.




It is also known to power existing actuators with pneumatic, or compressible fluids such as air in order to minimize cost and the difficulties associated with hydraulic and electro-mechanical actuators. However, pneumatic actuators have substantial difficulties associated with characteristics of compressible fluids and chambers having variable dimensions, etc. For example, as a chamber on one side of a piston receives compressed air to move the piston away from that chamber, the piston resists movement due to stiction, wherein seals between the piston and an interior wall of the container housing the piston, such as a cylinder, tend to adhere to the cylinder wall as a function of a pressure of the incoming pressure of the compressed air. When the stiction resistance is finally overcome, the piston commences to move and it acquires an inertia of the load that tends to sustain movement of the piston at a lower force then that required to commence movement of the piston. As the piston moves within the cylinder, the dimensions of the chamber of the piston receiving the compressed air changes, so that a constant feed of the compressed air will not exert a constant force upon the piston, and compensation in the rate of delivery of the compressed air must be made if precision is required in a rate of movement of any load secured to the piston, or to a rod, or to a load carriage secured to the piston. A constant rate of movement of the piston will also be effected by variations in dynamic forces acting upon the load, such as mechanical linkages, etc., that will cause the load to change its resistance, thereby interrupting a constant rate of motion of the piston. When it is desired to stop the moving piston at a precise location, it is necessary to take into consideration a limited braking capacity of the compressible fluid within a chamber of the cylinder into which the piston is moving as the compressible fluid is compressed by the force of the moving piston. Because of the limited braking capacity of the compressible fluid, precise motion control is unobtainable under normal conditions.




Many efforts have been undertaken to provide pneumatic actuators that provide for a relatively constant rate of motion of a load carriage and that can accurately and rapidly position a load in a repetitive fashion between varying positions. One exemplary pneumatic linear actuator is sold under the trademark “PRECISIONAIRE” by the TOL-O-MATIC, Inc. company of Hamel, Minn., U.S.A. The “PRECISSIONAIRE” actuator utilizes an elongate, hollow container housing a piston linked to a load carriage, wherein the piston is also secured to a toothed belt that forms an endless loop extending between pulleys at opposed ends of the hollow container or cylinder. A complex proportional magnetic particle brake is secured to one pulley along with a rotary encoder that is in communication with a controller which cooperate to control a rate of motion of the load carriage by braking, and to control accurate positioning by the rotary encoder and controller. While such hybrid mechanical and pneumatic actuators offer some of the convenience of compressed air pneumatic actuators, they are nonetheless expensive to manufacture and service, and are essentially limited to linear actuators. In many situations, their accuracy for position location is not satisfactory for sensitive applications.




Accordingly, there is a need for an inexpensive actuator that provides the efficiency and low cost of pneumatic actuators with the precision of rates of motion and positioning provided by hydraulic actuators or servo motors for all applications from robotics to precision assembly.




SUMMARY OF THE INVENTION




The invention is a bi-fluid actuator for precise bi-directional movement and positioning of a mechanical object. The bi-fluid actuator includes a pneumatic fluid container containing a compressible, pneumatic fluid; a hydraulic fluid container containing a non-compressible, hydraulic fluid; a first mechanical object positioned between a first chamber and an opposed second chamber of the pneumatic fluid container so that the first mechanical object may be impacted and moved by the pneumatic fluid; a second mechanical object linked to the first mechanical object and positioned so that the second mechanical object may be impacted and positioned by the hydraulic fluid; a pneumatic fluid controller that selectively directs pressurized pneumatic fluid into either the first or opposed second chamber of the pneumatic fluid container; and a hydraulic fluid controller that selectively permits passage of the hydraulic fluid between the first and opposed second chambers of the hydraulic container, so that the pneumatic fluid controller selectively powers the first and linked second mechanical objects to move in either a first or opposed second direction, and the hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the second and linked first mechanical object in the first or opposed second direction by selectively permitting, controlling a rate of, and then terminating passage of the hydraulic fluid between the opposed first and second chambers of the hydraulic fluid container. In essence, the hydraulic controller and hydraulic container form a closed loop hydraulic circuit that provides for flow control and accurate positioning while the pneumatic fluid powers movement of the first and second linked mechanical objects.




In an exemplary dual rod embodiment of the bi-fluid actuator, the pneumatic and hydraulic fluid containers are adjacent hollow, elongate containers, the first and second mechanical objects are pistons with rods within the hollow, elongate containers that are connected by way of the rods extending out of the containers to contact and move a load carriage typically utilized to precisely move an apparatus in automated assembly or manufacturing. By powering movement of the load carriage with a compressible or compressed, pneumatic fluid such as air, and controlling movement rate and positioning of the carriage with a non-compressible, fluid such as standard hydraulic fluid, precision of movement and positioning may be achieved by simply controlling passage of the non-compressible, hydraulic fluid at very modest pressure loads. The hydraulic fluid is selectively directed by the hydraulic fluid controller to flow through the controller between the first and second chambers of the hydraulic fluid container.




For example, if it is desired to move the load carriage away from the first chamber of the hydraulic fluid container, the chamber of the pneumatic fluid container aligned with the first chamber of the hydraulic fluid container receives compressed fluid from the pneumatic fluid controller. The hydraulic fluid controller then permits movement of the non-compressible, hydraulic fluid to pass from the second chamber into the first chamber of the hydraulic fluid container and the pneumatic fluid will then power movement of the linked first and second mechanical objects and load carriage away from the chamber having the compressed fluid, away from the first chamber of the hydraulic fluid container until a desired position of the load carriage is obtained. At that point the hydraulic fluid controller then terminates passage of the hydraulic fluid into the first chamber, thereby terminating further movement of the linked first and second mechanical objects and load carriage.




The bi-fluid actuator therefore provides for an elegant, low-powered, clean solution to precise movement of automated mechanical objects. Because the hydraulic fluid may control positioning at low pressure loads in a closed system, traditionally expensive and complicated sealing, feeding, and pressurizing of known hydraulic systems in automated actuators may be avoided. Because freely available, compressible, air fluid is utilized only for powering movement of the first mechanical object, and hence the load carriage, the known difficulties of accurate positioning of traditional pneumatic actuators is avoided. Accurate movement rates and positioning is achieved by movement of the second mechanical object by the hydraulic fluid through a cooperative integration of the hydraulic fluid controller with the pneumatic fluid controller. Additionally, because the powering source is readily available air, substantial power is available for moving high mass loads upon the load carriage without known cost and environmental risk factors associated with complex, highly pressurized hydraulic actuators.




Accordingly, it is a general object of the present invention to provide a bi-fluid actuator that overcomes deficiencies of prior actuators in accurate movement of a load.




It is a more specific object to provide a bi-fluid actuator that provides for precision of a rate of motion and of positioning of a load without pumping a non-compressible, hydraulic fluid.




It is yet another object to provide a bi-fluid actuator that may be utilized as a linear, or rotary actuator.




It is a further object to provide a bi-fluid actuator that may be produced utilizing either metal or plastic components.




It is still another object to provide a bi-fluid actuator that may be utilized as either a rodless actuator, or as a moving rod actuator.




These and other objects and advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

is a schematic view of a bi-fluid actuator constructed in accordance with the present invention as a dual rod embodiment of the bi-fluid actuator.





FIG. 2

is a partial fragmentary, perspective of a single rod embodiment of the bi-fluid actuator.





FIG. 2A

is a first partial view of the

FIG. 2

single rod embodiment of the bi-fluid actuator.





FIG. 2B

is a second partial view of the

FIG. 2

single rod embodiment of the bi-fluid actuator.





FIG. 3

is a partial fragmentary, perspective view of a rodless piston embodiment of the bi-fluid actuator.





FIG. 4

is a schematic view of a rodless valved piston embodiment of the bi-fluid actuator.





FIG. 4A

is an enlarged, partial view of the

FIG. 4

rodless valved piston embodiment of the bi-fluid actuator.





FIG. 4B

is an exploded view of a second mechanical object of the

FIG. 4

rodless valved piston embodiment of the bi-fluid actuator.





FIG. 5

is an exploded, perspective view of a rotary embodiment of the bi-fluid actuator.





FIG. 6

is an exploded, perspective view of a rotary vane embodiment of the bi-fluid actuator.





FIG. 7

is a fragmentary, perspective view of a mechanically valved embodiment of the bi-fluid actuator.





FIG. 7A

is a blow-up of a segment of

FIG. 7













DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS




In

FIG. 1

, a dual rod embodiment of the bi-fluid actuator is shown, and generally designated by the reference numeral


10


. The dual rod embodiment


10


includes a hollow, elongate pneumatic fluid container


12


and an adjacent hollow, elongate hydraulic fluid container


14


. A first mechanical object


16


is in the form of a first piston within the pneumatic fluid container


12


, and a second mechanical object


18


is in the form of a second piston within the hollow hydraulic fluid container


14


. A first rod


20


is connected to the first mechanical object


16


, and a second rod


22


is connected to and passes through the second mechanical object


18


. The two rods


20


,


22


are secured to a load or load carriage


24


typically utilized to precisely move an apparatus in automated assembly or manufacturing. The load carriage


24


may have a plurality of wheels


25


A,


25


B or other known structures to facilitate back and forth motion. A hydraulic fluid controller


26


, such as a proportional hydraulic flow control valve, is secured in fluid communication through a hydraulic lines


27


A,


27


B with a first hydraulic fluid chamber


28


and a second hydraulic fluid chamber


30


defined on opposed sides of the second piston


18


so that the hydraulic fluid controller


26


controls flow of a non-compressible fluid, such as hydraulic fluid, between the first and second hydraulic fluid chambers


28


,


30


to thereby control movement of the second mechanical object or piston


18


and second rod


22


.




A pneumatic fluid controller


32


, such as a four-way pneumatic valve, is secured in fluid communication through pneumatic lines


33


A,


33


B between a first pneumatic fluid chamber


34


and a second pneumatic fluid chamber


36


defined on opposed sides of the first mechanical object or piston


16


so that the pneumatic fluid controller


32


may permit pressurized, compressed or compressible fluid into either the first or second pneumatic fluid chambers


34


,


36


, to power the first piston


16


, first rod


20


and load carriage


24


secured thereto to move in a direction either toward or away from the pneumatic and hydraulic containers


12


,


14


.




By powering movement of the load carriage


24


with a compressible, pneumatic fluid such as air, and controlling movement rate and positioning of the carriage with a non-compressible fluid such as standard hydraulic fluid, precision of movement and positioning of the load carriage


24


may be achieved by simply controlling passage of the non-compressible, hydraulic fluid with the hydraulic fluid controller


26


. The hydraulic fluid is selectively directed by the hydraulic fluid controller


26


to flow through the controller


26


between the first and second chambers


28


,


30


of the hydraulic fluid container


14


.




A positioning controller


38


may be secured to detect the position of the load carriage


24


between movement range limits


39


A,


39


B of the load carriage. The positioning controller may detect the position of the load carriage either optically, mechanically, electrically, or through any known positioning detection technology, and to communicate detected positioning information through a first position information transfer mechanism


41


A to the hydraulic fluid controller


26


, and through a second position information transfer mechanism


41


B to the pneumatic fluid controller


32


. The three controllers


38


,


26


,


32


may therefore function cooperatively to position the load carriage


24


in desired positions at selected times, and to move the load carriage


24


between selected positions within the movement range limits


39


A,


39


B at desired rates of travel. The positioning controller


38


may be any known controller capable of implementing a positioning program including detecting positions, communicating detected positions to pneumatic and/or hydraulic controllers or control valves so that the control valves may open or close in response to the communications from the positioning controller, as is well known in the art of automated actuators. The first and second position information transfer mechanisms


41


A,


41


B may be standard electric lines, or may be wireless transmission apparatus known in the art. The positioning controller


38


may include, or be in electrical communication with, an overall controller means for receiving information from and transmitting information to the pneumatic and/or the hydraulic controllers


26


,


32


through the first and second position information transfer mechanisms


41


A,


41


B so that the positioning controller


38


may change, for example, to a program of detection and/or implementation of differing desired positions and/or rates of travel of the load carriage


24


. The positioning controller


38


may include, for example, computers utilized for controlling positions and rates of travel of moving objects; proximity switches; linear encoders; programmable logic controllers; etc. In certain embodiments, the positioning controller


38


may communicate with only the hydraulic fluid controller


26


or only the pneumatic fluid controller


32


. An exemplary positioning controller utilized in actuator technology that could be utilized with the various embodiments of the bi-fluid actuator disclosed herein is manufactured by the GALIL Motion Control Company, of Mountain View, Calif., U.S.A., and is available under the model number “DMC1415 CONTROLLER”.




It is stressed that the phrase “pneumatic fluid controller” is meant to include the capacity of selectively compressing and/or directing flow of a compressed or compressible, pneumatic fluid, such as air, and may also include an ordinary air compressor as is often included in association with regular and proportional valve controllers known in the art. For purposes herein, the word “selectively” as in “a pneumatic controller” or “hydraulic controller” that “selectively directs”, or “selectively permits”, is meant to indicate that the controller may be controlled to stop flow; permit flow at any of varying rates of flow; or pump flow of a fluid passing through the controller. It is also to be understood that for purposes herein, the term “chamber” as used to describe voids defined on opposed sides of mechanical objects such as the above-described first and second pistons


16


,


18


, is meant to describe chambers or voids of varying dimensions and volumes as the mechanical objects move, and is not to be construed as voids of limited or specific dimensions or volumes.




The following embodiments of the bi-fluid actuator also include a pneumatic fluid controller, a hydraulic fluid controller, and may also include a positioning controller appropriate for a particular task of the described embodiments of the bi-fluid actuators. The pneumatic, hydraulic and positioning controllers described below also operate in essentially the same manner as described above or as known in the art, unless otherwise indicated, and therefore the operation of those components in the following embodiments will not be repeatedly described.




In

FIG. 2

, a single rod embodiment of the bi-fluid actuator


40


is shown, wherein a pneumatic fluid container


42


surrounds as a sleeve a coaxial hydraulic fluid container


44


. A first mechanical object


46


is in the form of an “0”, or doughnut-shaped piston that surrounds or partially surrounds the hydraulic fluid container


44


, and a second mechanical object


48


is in the form of a piston within the hydraulic fluid container


44


that is mechanically linked to the first mechanical object


46


through a solid shaft


49


that is secured to and end cap


51


, which in turn is mechanically secured to a hollow rod


50


. The hollow rod


50


is secured to the first mechanical object


46


and passes out of the pneumatic fluid container


42


to be secured to and move a load carriage (not shown in

FIG. 2

) secured to the hollow rod


50


by way of a threaded portion of the end cap


51


, or other securing apparatus.




The first mechanical object


46


is secured between a first pneumatic fluid chamber


52


and a second pneumatic fluid chamber


54


of the pneumatic fluid container


42


. The second mechanical object


48


is secured between a first hydraulic fluid chamber


56


and a second hydraulic fluid chamber


58


of a hydraulic fluid container


44


, which includes the hollow rod


50


. A hydraulic fluid reservoir tube


59


lies adjacent and parallel to the hydraulic fluid container


44


, and in fluid communication with the first hydraulic chamber


56


of the hydraulic container


44


. The first mechanical object


46


may also surround the hydraulic reservoir tube


59


. Hydraulic fluid passes from the second hydraulic fluid chamber


58


through a hydraulic controller


62


into the hydraulic fluid reservoir tube


59


and then through a hydraulic fluid reservoir opening


57


defined within a hydraulic end cap


68


secured to the hydraulic fluid container


44


, and then into the first hydraulic chamber


56


to define a closed hydraulic loop. As the second mechanical object


48


moves along the hydraulic fluid container


44


away from the second hydraulic fluid chamber


58


, (from right to left as viewed in FIG.


2


), hydraulic fluid moves from the first hydraulic fluid chamber


56


through the fluid reservoir opening


57


into the hydraulic fluid reservoir tube


59


, and through a header


65


that seals both the second pneumatic chamber


54


and the second hydraulic chamber


58


. The hydraulic fluid reservoir tube


59


is a fluid extension of the first hydraulic chamber


56


.




A pneumatic fluid controller


60


is secured in fluid communication between the first and second pneumatic chambers


52


,


54


by way of standard pneumatic lines


61


A,


61


B, so that the pneumatic controller


60


may selectively direct and/or compress pneumatic fluid into either the first or second pneumatic fluid chambers


52


,


54


of the pneumatic fluid container


42


. A hydraulic fluid controller


62


is secured in fluid communication between the first and second hydraulic fluid chambers


56


,


58


by way of standard hydraulic lines


63


A,


63


B. Hydraulic line


63


A is in fluid communication between the hydraulic fluid controller


62


and the first hydraulic fluid chamber


56


through the hydraulic reservoir tube


59


, and hydraulic line


63


B is in fluid communication between the hydraulic fluid controller


62


and the second hydraulic fluid chamber


58


. Both hydraulic lines


63


A,


63


B pass through the header


65


secured in a first end seal


71


of the pneumatic fluid container


42


that directs the hydraulic fluid into the hydraulic fluid reservoir tube


59


or the second hydraulic fluid chamber


58


.




In

FIG. 2A

, a stationary hydraulic circuit


43


is shown and includes the hydraulic container


44


, which is secured to the header


65


on one end, and an opposed end of the hydraulic container


44


is secured to a hydraulic end cap


68


so that the hydraulic container


44


is mechanically supporting the hydraulic end cap


68


. The hydraulic fluid reservoir tube


59


is attached to the header


65


on one end and an opposed end of the hydraulic fluid reservoir tube


59


is attached to the hydraulic end cap


68


so that the hydraulic fluid reservoir tube


59


also mechanically supports the hydraulic end cap


68


. The hydraulic fluid reservoir tube


59


is in fluid communication with the hydraulic fluid reservoir opening


57


defined within the end cap


68


, and the opening


57


allows fluid to flow through the hydraulic fluid reservoir tube


59


and into or out of the first hydraulic fluid container


56


. The header


65


, the hydraulic chamber


44


, the hydraulic fluid reservoir tube


59


, the hydraulic fluid reservoir opening


57


, and the hydraulic end cap


68


do not move relative to each other.




A moving hydro-pneumatic circuit


45


is shown in

FIG. 2B

, and comprises the second mechanical object


48


which is secured to the inner solid shaft


49


, that is secured to the threaded adapter


51


, which in turn is secured to the hollow rod


50


. The hollow rod


50


is secured to the first mechanical object


46


. The entire assembly of the second mechanical object


48


, the inner solid shaft


49


, the threaded adapter


51


, the hollow rod


50


, and the first mechanical object


46


all move as one circuit


45


within the compressible or pneumatic fluid container


42


.




As shown in

FIG. 2

, the first mechanical object


46


, upon being impacted by air or another compressible fluid, moves the hollow rod


50


so that the threaded adapter of the end cap


51


moves closer or further away from a second end seal


69


, similar to typical air cylinders on the market. The air or other compressible fluid enters through lines


61


A or


61


B and creates motive force against the first mechanical object


46


to extend or retract the hollow shaft


50


. The first and second hydraulic chambers


56


and


58


are defined within the hydraulic container


44


, which includes the hollow rod


50


, as the moving hydro-pneumatic circuit


45


is integrated with stationary hydraulic circuit


43


, as shown in FIG.


2


. The first hydraulic chamber


56


acts as an accumulator to accept hydraulic fluid from the hydraulic fluid reservoir opening


57


or to force hydraulic fluid back out the hydraulic fluid reservoir opening


57


. The hydraulic fluid reservoir opening


57


, allows hydraulic fluid to flow between the hydraulic fluid reservoir tube


59


and the first hydraulic chamber


56


. The hydraulic fluid reservoir tube


59


, allows hydraulic fluid to flow through line


63


A into the hydraulic fluid controller


62


, and then into the second hydraulic chamber


58


as the hydraulic fluid is moved in one direction or another by movement of the second mechanical object


48


which is powered by movement of the first mechanical object


46


. The closed loop hydraulic circuit consisting of the moving hydro-pneumatic circuit


45


and the stationary hydraulic circuit


43


can be used to control the rate of movement and/or starting and stopping of the hollow rod


50


. Due to the sealed environment inside the system it is necessary to include a relief opening


53


for air to escape from the hollow rod


50


.




A positioning controller


64


may be secured to detect a position of any load carriage or apparatus (not shown) secured to the rod


50


moved by the linked first and second mechanical objects


46


,


48


between range limits


66


A,


66


B. The positioning controller


64


may communicate detected positioning information through a first information transfer mechanism


67


A to the pneumatic fluid controller


60


, and through a second information transfer mechanism


67


B to the hydraulic controller


62


. The three controllers


60


,


62


, and


64


may be integrated, such as through computerized overall controller means known in the art for positioning the hollow rod


50


in desired positions at desired times, and to be moved at desired rates of speed.




In

FIG. 3

, a rodless piston embodiment of the bi-fluid actuator


66


is shown, wherein a pneumatic fluid container


73


is in the shape of a sleeve, or partial sleeve defining an “O” or “C” shaped void, and a hydraulic fluid container


70


is a hollow, elongate container positioned within and coaxial with the pneumatic fluid container


73


. A first mechanical object


72


is an “O” or “C” shaped piston magnetically (as shown in

FIG. 3

) or mechanically linked to a second mechanical object


74


which is in the shape of a rodless or flat piston. The first mechanical object


72


is dimensioned to fit within the pneumatic fluid container


73


while making a sliding air seal within the container


73


. The first mechanical object


72


may also be dimensioned to surround, or partially surround the hydraulic fluid container


70


, and is also mechanically or magnetically (as shown in

FIG. 3

) linked to a load carriage


76


supported on a track


78


adjacent to the pneumatic fluid container


73


and extending between a first end seal


77


and a second end seal


79


of the pneumatic fluid container


73


. The first mechanical object


72


is secured between a first pneumatic fluid chamber


80


and a second pneumatic fluid chamber


82


. The second mechanical object


74


is secured between a first hydraulic fluid chamber


84


and a second hydraulic fluid chamber


86


.




A pneumatic fluid controller


88


is secured in fluid communication through pneumatic lines


87


A,


87


B between the first and second pneumatic fluid chambers


80


,


82


. A hydraulic fluid controller


90


is secured in fluid communication through hydraulic line


91


A,


91


B between the first and second hydraulic fluid chambers


84


,


86


. As described above with reference to

FIG. 2

, The pneumatic controller


88


may direct compressed pneumatic fluid through pneumatic line


87


A into the first pneumatic fluid chamber


80


, and permits pneumatic fluid to move out of the second pneumatic fluid chamber


82


through pneumatic line


87


B to be released to the atmosphere. The hydraulic controller


90


may then permit passage of hydraulic fluid from the second hydraulic fluid chamber


86


, through hydraulic line


91


B, through the hydraulic fluid controller


90


, through hydraulic fluid line


91


A, and into the first hydraulic fluid chamber


84


in order to permit movement toward the second end seal


79


of the second mechanical object


74


, linked first mechanical object


72


, and the load carriage


76


that is also linked to the first mechanical object


72


.




A positioning controller


92


may be secured or arranged properly in order to detect a position of the load carriage


76


or other apparatus secured to the linked first and second mechanical objects


72


,


74


between movement range limits


89


A,


89


B. The positioning controller


92


may communicate detected positioning information through a first information transfer mechanism


93


A to the pneumatic fluid controller


88


, and through a second information transfer mechanism


93


B to the hydraulic controller


90


. The positioning, pneumatic and hydraulic controllers


92


,


88


,


90


would work generally as described above to control position and rate of travel of the load carriage


76


. The positioning controller may include, be integrated with, or be in communication with an overall controller means for communicating detected and desired positioning commands to the hydraulic and pneumatic controllers


88


,


90


, as described above for all embodiments of the bi-fluid actuator.




In

FIG. 4

, a rodless valved piston embodiment of the bi-fluid actuator


94


is shown, wherein a pneumatic fluid container


96


is in the shape of a sleeve, or partial sleeve, defining an “O” of “C” shaped void, and a hydraulic fluid container


98


is a hollow elongate container positioned within and coaxial with the pneumatic fluid container


96


. A first mechanical object


100


is in the shape of a “O” or “C” shaped piston magnetically (as shown in

FIG. 4

) or mechanically linked to a second mechanical object


102


which is in the shape of a rodless piston. The first mechanical object


100


is mechanically or magnetically linked (as shown in

FIG. 4

) to a load carriage


104


supported on a track


106


adjacent to or defined in the pneumatic fluid container


96


. The track


106


extends between a first header


105


and a second header


107


of the pneumatic fluid container


96


. The first mechanical object


100


is secured between a first pneumatic fluid chamber


108


and a second pneumatic fluid chamber


110


. The second mechanical object


102


is secured between a first hydraulic fluid chamber


112


and a second hydraulic fluid chamber


114


.




A pneumatic fluid controller


116


is secured in fluid communication through pneumatic lines


117


A,


117


B between the first pneumatic fluid chamber


108


through a first header


119


in the first header


105


, and through a second header


121


in the second header


107


. A hydraulic fluid controller


118


is secured in fluid communication between the first and second hydraulic fluid chambers


112


,


114


. A positioning controller


120


is secured to detect a position of the load carriage


104


or other apparatus secured to the linked first and second mechanical objects


100


,


102


between movement range limits


115


A,


115


B. The positioning controller


120


may communicate detected positioning information through an information transfer mechanism


123


to the pneumatic fluid controller


116


. The positioning controller


120


may be integrated with or be in communication with an overall controller means. A plurality of seals


111


, such as standard “O-ring” seals, are secured between the first and second mechanical objects


100


,


102


and the pneumatic and hydraulic fluid containers


96


,


98


, in a standard manner well known in the art to provide fluid seals while permitting sliding motion.




As shown in

FIG. 4

, in the rodless valved piston embodiment of the bi-fluid actuator


94


, the hydraulic fluid controller


118


is in the form of a two-way, spring pre-set valve


118


secured within the second mechanical object


102


, so that a specific valve-override pressure load of the pneumatic fluid directed by the pneumatic fluid controller


116


to either the first or second pneumatic fluid chambers


108


,


110


will direct an adequate force through the linked first and second mechanical objects


100


,


102


to override a pre-set pressure of the valve


118


to thereby open it to movement of the non-compressible, hydraulic fluid through the valve


118


. That permits movement of the second mechanical object


102


, linked first mechanical object


100


and load carriage


104


away from the pneumatic fluid chamber having the specific valve-override pressure load, or the powered chamber. The positioning controller


120


and the pneumatic fluid controller


116


then cooperate to decrease the compressed fluid load to the powered chamber whenever the positioning controller detects the load carriage at a desired location so that the hydraulic fluid controller or two-way, spring pre-set valve


118


closes to terminate movement of the hydraulic fluid through the valve


118


, and thereby terminate movement of the second mechanical object


102


, first mechanical object and linked load carriage


104


.




As best seen in

FIGS. 4A and 4B

, the two-way, spring pre-set valve


118


includes an outer sleeve


250


that houses a by-pass barrel


252


. The by-pass barrel


252


defines at least one or a plurality of first hydraulic chamber fluid by-pass grooves


254


A,


254


B that are in fluid communications with a corresponding plurality of first hydraulic fluid chamber ports


256


A,


256


B (shown best in FIG.


4


A). The by-pass barrel also defines at least one or a plurality of second hydraulic fluid chamber by-pass grooves


258


A,


258


B, that are in fluid communication with a corresponding plurality of second hydraulic fluid chamber by-pass ports


260


A,


260


B. The by-pass barrel


252


also defines a by-pass throughbore


131


having a spring wall


262


(shown only in

FIGS. 4 and 4A

) that may be integral with the by-pass barrel


252


, or secured within the barrel


252


, between the first hydraulic chamber by-pass ports


256


A,


256


B and the second hydraulic chamber by-pass ports


258


A,


258


B.




A first coiled spring


264


is secured within the by-pass throughbore


131


against a side of the spring wall


262


nearest to the first hydraulic chamber


112


, and a second coiled spring


266


is secured within the by-pass throughbore


131


against a side of the spring wall


262


nearest the second hydraulic fluid chamber


114


. A first moving seal


268


is secured to the first coiled spring


264


, and a second moving seal


270


is secured to the second coil spring


266


. A first seal lock


272


is secured within the by-pass throughbore


131


adjacent to the first moving seal


268


when the first coiled spring


264


is extended so that the when the first coiled spring


264


is compressed, a void is defined between the first seal lock


272


and the first moving seal


268


. The first seal lock


272


defines a first by-pass passage


274


. A second seal lock


276


is secured within the by-pass throughbore


131


adjacent to the second moving seal


270


when the second coiled spring


266


is extended so that the when the second coiled spring


266


is compressed, a void is defined between the second seal lock


276


and the second moving seal


270


. The second seal lock defines a second by-passage


278


.




The diameters of the first and second moving seals


268


,


270


are cooperatively dimensioned to be larger than corresponding diameters of the first and second by-pass passages


274


,


278


so that whenever the first or second coiled springs


264


,


266


force the first or second moving seals


268


,


270


into contact with adjacent first or second seal locks


272


,


276


, the moving seals


268


,


270


completely block the first or second by-pass passage


274


,


278


thereby restricting movement of the hydraulic fluid through the blocked first or second by-pass passage


274


,


278


. Such blocking may be facilitated by having chamfered ends of the first and second moving seals


268


,


270


, or by other known sealing means known in the art, such as compressible “O-ring” seals (not shown), etc. Shortest diameters of the first and second moving seals


268


,


270


are also cooperatively dimensioned to be less than diameters of the by-pass throughbore


131


, so that whenever the first or second moving seal


268


,


270


are displaced out of contact with the first or second seal lock


272


,


276


, hydraulic fluid may flow around the first or second moving seal


268


,


270


, and then into either the plurality of first or second hydraulic fluid chamber by-pass ports


256


A,


256


B,


260


A,


260


B and their corresponding plurality of first or second hydraulic fluid chamber grooves


254


A,


254


B,


258


A,


258


B.




In use of the two-way, spring pre-set valve


118


, the first and second coil springs


264


,


266


are selected to have a specific compressive force or valve-override pressure load that must be achieved to compress the springs


264


,


266


. If it is desired to move the load carriage in a specific direction to a specific location, such in the direction of the arrow


133


in

FIG. 4

, the pneumatic controller, which may be an overall controller means as described above, or may be a pneumatic proportional valve integrated with a four-way solenoid valve, directs an adequate air pressure into the second pneumatic chamber


110


to overcome the valve-override pressure load of the first coil spring


264


. The first coil spring


264


and first moving seal


268


then move out of contact with the first seal lock


272


(as shown best in

FIG. 4A

) so that hydraulic fluid may move from the first hydraulic fluid chamber


1112


through the by-pass throughbore


131


into the second hydraulic fluid chamber


114


, thereby permitting motion of the second mechanical object


102


, the first mechanical object


100


and load carriage.




Whenever it is desired to stop movement of the load carriage, such as when the positioning controller


120


detects the load carriage at a desired location, then the pneumatic controller


120


or any other known controller means directs the pneumatic controller to decrease the pressure of the compressible fluid within the second pneumatic chamber


110


to below the specific valve-override pressure load of the first coil spring


264


. The spring


264


then moves the first moving seal


268


back into contact with the first seal lock


272


so that the hydraulic fluid can no longer move through the by-pass throughbore, or actually, so that the second mechanical object


102


can no longer move through the hydraulic fluid within the hydraulic container


98


, thereby terminating movement of the second mechanical object


102


.




The two-way, spring pre-set valve


118


may be in the above-described form, or may be any two-way, spring pre-set valve means for permitting and terminating two-way flow of a non-compressible fluid through the valve in response to pressure changes acting upon the valve that are known in the art. Additionally, the two-way, spring pre-set valve


118


may be situated in fluid communication with the second mechanical object


102


through standard hydraulic lines, but external to the pneumatic and hydraulic containers


96


,


98


.




The pneumatic controller


116


must include a proportional pressure valve (not shown) in fluid communication with a four-way solenoid valve (not shown), that is in fluid communication with the pneumatic lines


117


A,


117


B. The positioning controller


120


would be in communication with the proportional pressure valve and/or the four-way solenoid valve. The pneumatic controller may also include an air pressure monitoring device (not shown) that is constantly sending pressure readings within the powered pneumatic chamber (such as the second pneumatic chamber


110


in the above example of operation) to the pneumatic controller, or an overall controller integrated with or in communication with the pneumatic controller


116


. Additionally, the pneumatic controller may include a precision regulator known in the art that is able to change precise pressure levels very quickly for enhanced efficiency of operation of the rodless valved piston embodiment


94


of the bi-fluid actuator.




In

FIG. 5

, a rotary embodiment of the bi-fluid actuator


122


is shown, wherein a pneumatic fluid container


124


is in the form of a first deformable tube, and a hydraulic fluid container


126


is in the form of a second deformable tube secured adjacent to the first deformable tube


124


in parallel circular alignment. Such “deformable tubes” are commonly referred to in the art as “peristaltic tubes”. Both the first and second deformable tubes


124


,


126


are secured within a cylindrical housing


128


. A first mechanical object


130


is in the form of a first pinch roller that pinches or deforms the pneumatic fluid container


124


against the housing


128


, and a second mechanical object


132


is in the form of a second pinch roller that is secured to the first pinch roller


130


, and that pinches or deforms the hydraulic fluid container


126


against the housing


128


.




The first and second mechanical objects


130


,


132


or pinch rollers


130


,


132


are secured to an armature


134


that is dimensioned to rotate about a center of a circle defined by the first and second deformable tubes


124


,


126


and housing


128


. The armature


134


may be secured to a keyed shaft


153


which is secured to a rotatable bearing


157


to which a load carriage (not shown) or other mechanical structure that is to be rotated between specific positions at specific rates of travel may be secured. Housing cap


135


may be secured to the cylindrical housing


128


. The first pinch roller or first mechanical object


130


deforms the pneumatic fluid container


124


to define a first pneumatic fluid chamber


136


and a second pneumatic fluid chamber


138


on an opposed side of the first pinch roller


130


. The second pinch roller or second mechanical object


132


deforms the hydraulic fluid container


126


to define a first hydraulic fluid chamber


140


and a second hydraulic fluid chamber


142


on opposed sides of the second pinch roller


132


.




A pneumatic fluid controller


144


is secured in fluid communication between the first and second pneumatic fluid chambers


136


,


138


by way of pneumatic lines


137


A,


137


B that are secured to a junction header


139


that defines separate pneumatic passages to which the first and second pneumatic chambers


136


,


138


are secured in fluid communication. A hydraulic fluid controller


146


is secured in fluid communication by way of hydraulic lines


141


A,


141


B between the controller


146


and the junction header


139


that also defines separate hydraulic passages secured in fluid communication with the first and second hydraulic fluid chambers


140


,


142


.




A positioning controller


148


may be secured or arranged properly in order to detect a rotational position of the bearing


157


or load carriage secured thereto between movement range limits


149


A,


149


B. The positioning controller


148


may communicate detected positioning information through a first information transfer mechanism


151


A to the pneumatic fluid controller


144


, and through a second information transfer mechanism


151


B to the hydraulic controller


146


. The positioning, pneumatic and hydraulic controllers


148


,


144


,


146


would work generally as described above to control position and rate of travel of the bearing


157


. In the rotary embodiment of the bi-fluid actuator


122


, the keyed axle shaft


153


would be dimensioned to mate with a keyed axle throughbore


155


defined within the armature


134


to be secured to the bearing


157


to rotationally secure the armature


134


to the bearing


157


.




The action of the second mechanical object or second pinch roller


132


being impacted and moved by movement of the hydraulic fluid between the first and second hydraulic chambers


140


,


142


is similar in structure to known peristaltic pumps well known in the art of pumping fluids through deformable tubes where it is important that the fluid remain untouched by mechanical objects such as pump impellers, as is common in human intravenous pumps, etc. However in the present rotary embodiment of the bi-fluid actuator


122


, instead of moving the hydraulic fluid, the second mechanical object or second pinch roller


132


is being powered by the force of the compressed pneumatic fluid upon the linked first mechanical object or first pinch roller


130


, and a rate of movement, direction of movement, and positioning of the linked first and second mechanical objects is being controlled by movement of the hydraulic fluid between the first and second hydraulic fluid chambers


136


,


138


, as controlled by the hydraulic fluid controller


146


.




In

FIG. 6

, a rotary vane embodiment of the bi-fluid actuator


150


is shown, wherein a pneumatic fluid container


152


is in the form of a half-cylinder, and a hydraulic fluid container


154


is in the form of an opposed half cylinder defined within a common cylindrical housing


156


. A non-rotating containment wall


158


is secured between and defines non-circular walls of the pneumatic and hydraulic fluid containers


152


,


154


. A first mechanical object


160


is in the form of a first half vane that bi-sects the pneumatic fluid container


152


, and a second mechanical object


162


is in the form of a second half vane that bi-sects the hydraulic fluid container


154


, wherein the first and second half vanes or first and second mechanical objects


160


,


162


are linked to each other and to an armature


164


at the center of a circle defined by the housing


156


so that movement of the first half vane


160


moves both the second half vane


162


and armature


164


. The first half vane or first mechanical object


160


defines a first pneumatic fluid chamber


166


and a second pneumatic fluid chamber


168


on opposed sides of the first half vane


160


. The second half vane or second mechanical object


162


defines a first hydraulic fluid chamber


170


and a second hydraulic fluid chamber


172


on opposed sides of the second half vane


162


.




A header cap


165


is dimensioned to be secured in a non-rotational manner to the cylindrical housing


156


and to make a fluid seal of the pneumatic and hydraulic containers


152


,


154


with the header cap


165


. The header cap


165


also includes an armature sleeve


167


dimensioned to permit the central armature


164


to pass through the sleeve


167


while restricting passage of fluid through the sleeve


167


so that a load carriage (not shown) may be secured to the central armature extending beyond the header cap


165


to permit limited rotational movement of the load carriage. The header cap


165


also includes a first hydraulic fluid fitting


169


and a second hydraulic fluid fitting


171


that each define separate hydraulic fluid passages. The first hydraulic fitting


169


is secured on or defined in the header plate


165


so that hydraulic fluid passing through it will be directed into or out of the first hydraulic fluid chamber


170


, and the second hydraulic fluid fitting


171


is secured to or defined in the plate


165


so that hydraulic fluid passing through the fitting


171


will pass into or out of the second hydraulic fluid chamber


172


.




Similarly, the header plate


165


also includes a first pneumatic fluid fitting


173


and a second pneumatic fluid fitting


175


, both of which fittings


173


,


175


define separate pneumatic passages. The first pneumatic fitting


173


is defined in the header plate


165


so that pneumatic fluid passing through it will be directed into or out of the first pneumatic fluid chamber


166


, and the second pneumatic fluid fitting


175


is defined in the plate


165


so that pneumatic fluid passing through the fitting


175


will pass into or out of the second pneumatic fluid chamber


168


.




A pneumatic fluid controller


174


is secured in fluid communication between the first and second pneumatic fluid chambers


166


,


168


, by way of standard pneumatic lines


177


A,


177


B secured between the controller


174


and the first and second pneumatic fittings


173


,


175


of the header plate


165


. A hydraulic fluid controller


176


is secured in fluid communication between the first and second hydraulic fluid chambers


170


,


172


by way of standard hydraulic lines


179


A,


179


B secured between the controller


176


and the first and second hydraulic fittings


169


,


171


of the header plate


165


. A positioning controller


178


may be secured or arranged properly in order to detect a rotational position of the bearing central armature


164


or any load carriage (not shown) secured to the armature


164


between movement range limits


181


A,


181


B. The positioning controller


178


may communicate detected positioning information through a first information transfer mechanism


183


A to the pneumatic fluid controller


174


, and through a second information transfer mechanism


183


B to the hydraulic controller


176


. The positioning, pneumatic and hydraulic controllers


178


,


174


,


176


would work generally as described above to control position and rate of travel of the central armature


164


or any load carriage (not shown) secured thereto.




The rotary vane embodiment of the bi-fluid actuator


150


would be especially appropriate for rotational movement of objects having desired ranges of motion that are restricted to less than one hundred and eighty degrees, and wherein a desired rate of rotational motion may be significantly greater than an efficient rate of rotational motion for a load carriage rotated by the rotary embodiment of the bi-fluid actuator


122


described above and illustrated in FIG.


5


.




In

FIG. 7

, a mechanically valved embodiment of the bi-fluid actuator


180


is shown, wherein a pneumatic fluid container


182


is in the form of an elongate, hollow container. A first mechanical object is in the form of a piston


184


including a secured hollow rod


186


, wherein the rod passes out of the pneumatic fluid container


182


to be secured by a threaded rod adaptor


185


to a load carriage (not shown). A hydraulic fluid container


188


is in the form of a void defined within the hollow rod


186


of the first mechanical object or piston


184


. The piston


184


or the first mechanical object defines a first pneumatic fluid chamber


190


and a second pneumatic fluid chamber


192


on opposed sides of the piston


184


. A T-piston


191


including a seal


195


is secured adjacent to the first mechanical object or piston


194


and between the first and second pneumatic chambers


190


,


192


.




A mechanical valve hydraulic fluid controller


194


includes a second mechanical object or rotational port valve assembly


196


secured within the hydraulic fluid container


188


. The rotational port valve


196


includes a rotational port plate


213


that is secured to a valve stem


198


that is coaxial with the hollow rod


186


secured to the first mechanical object


184


, and that is secured to a mechanical valve trigger


200


positioned outside of the pneumatic fluid container


182


adjacent to a first end seal


187


of the pneumatic fluid container


182


. A second end seal


189


is secured to an opposed end of the pneumatic fluid container


182


, and the rod


186


passes through the second end seal


189


.




The valve stem


198


is supported within a stem sleeve


211


that surrounds the valve stem


198


, and the valve stem


198


and stem sleeve


211


terminate with the rotational port valve assembly


196


. As best seen in the blow-up insert of the rotational port valve assembly


196


in

FIG. 7A

, the valve stem


198


includes a rotational valve port plate


213


that defines one or more rotational hydraulic fluid ports


214


A,


214


B,


214


C and


214


D. The rotational valve port plate


213


is dimensioned to fit snugly within the hydraulic fluid container


188


so that hydraulic fluid may only pass through the rotational hydraulic fluid ports


214


A,


214


B,


214


C and


214


D of the rotational valve port plate


213


and not otherwise around the plate


213


. The stem sleeve


211


includes a stationary port plate


216


that defines one or more stationary hydraulic fluid ports


218


A,


218


B,


218


C,


218


D. The stationary valve port plate


216


is dimensioned to fit snugly within the hydraulic fluid container


188


so that hydraulic fluid may only pass through the hydraulic fluid ports


218


A,


218


B,


218


C,


218


D of the stationary port plate


216


and not otherwise around the plate


216


. The rotational port plate


213


is secured adjacent to the stationary port plate


216


so that no fluid can flow through the plates


213


,


216


unless the rotational hydraulic fluid ports


214


A,


214


B,


214


C,


214


D are aligned with the stationary hydraulic fluid ports


218


A,


218


B,


218


C,


218


D. The rotational port plate


213


is secured closely to the stationary port plate


216


by a raised boss


219


on the valve stem


198


adjacent to the first end seal


187


, so that the valve stem


198


may still be rotated to rotate the rotational port plate


213


while maintaining a seal between the rotational port plate


213


and stationary plate


216


.




By rotating the valve trigger


200


that is secured to the valve stem


198


within the fixed position stem sleeve


211


, the valve stem


198


is rotated so that the rotational valve port plate


213


and its rotational hydraulic fluid ports


214


A,


214


B,


214


C,


214


D may be rotated to overlie one of the stationary hydraulic fluid ports


218


A,


218


B,


218


C,


218


D of the stationary plate


216


, thereby permitting or terminating movement of the hydraulic fluid through the plates


213


,


216


as the entire hydraulic fluid chamber


188


moves along with the first mechanical object


184


and adjacent T-piston


191


that includes the hydraulic fluid chamber


188


. Rotating the valve


200


trigger so that the rotational hydraulic fluid ports


214


A,


214


B,


214


C of the rotational valve port plate


213


are not overlying the stationary hydraulic fluid ports


218


A,


218


B,


218


C,


218


D of the stationary valve port plate


216


immediately stops movement of the hydraulic fluid chamber


188


, and hollow rod


186


secured to the first mechanical object


184


or piston, adjacent to the T-piston


191


, as well as any load carriage or load (not shown) secured to the adaptor


185


of the rod.




A first hydraulic fluid chamber


202


and a second hydraulic fluid chamber


204


are defined within the hydraulic fluid container


188


on opposed sides of the rotational valve port plate


213


and stationary valve port plate


216


of the rotational port valve or second mechanical object


196


.




A pneumatic fluid controller


206


is secured in fluid communication by standard pneumatic lines


201


A,


201


B between the first and second pneumatic fluid chambers


190


,


192


. Pneumatic line


201


A is secured between the pneumatic fluid controller


206


and a first port


203


defined in the pneumatic fluid container


182


adjacent the first pneumatic chamber


190


and the first end seal


187


. Pneumatic line


201


B is secured between the pneumatic fluid controller


206


and a second port


205


defined in the pneumatic fluid container


182


adjacent the second pneumatic fluid chamber


192


and the second end seal


189


, as shown in

FIG. 7. A

positioning controller


208


may be secured or arranged properly in order to detect a position of the rod


186


of any load carriage (not shown) secured to the rod adaptor


185


between movement range limits


207


A,


207


B. The positioning controller


208


may communicate detected positioning information through a first information transfer mechanism


209


A to the pneumatic fluid controller


206


, and through a second information transfer mechanism


209


B to the mechanical valve trigger


200


.




The mechanical valve trigger


200


may be manually actuated by an operator (not shown) to move open or close the rotational port valve assembly


196


, to permit movement of the hollow rod


186


, and to control a rate of movement of the hollow rod


186


. The manual operation may be based upon sensed information from the positioning controller


208


, or in the event the positioning controller


208


is not being used, the operator may simply utilize the valve trigger


200


based upon visual observation or other information gathered directly by the operator. Alternatively, the valve trigger


200


may be electro-mechanically operated by apparatus known in the art in response to positioning and program information received from the positioning controller


208


. The positioning controller


208


, pneumatic controller


206


and an electro-mechanically operated trigger valve


200


would work generally as described above to control position and rate of travel of the hollow rod


186


or any load carriage (not shown) secured to the rod adaptor


185


.




In operation of the mechanically valved bi-fluid actuator


180


, rotation of the valve trigger


200


of the mechanical valve hydraulic fluid controller


194


permits movement of hydraulic fluid between the first and second hydraulic fluid chambers


202


,


204


. Therefore, whenever the first or second pneumatic fluid chambers


190


,


192


of the pneumatic fluid container


182


contain a compressed fluid and the valve trigger


200


is rotated, the movement of the non-compressible, hydraulic fluid between the first and second hydraulic fluid containers


202


,


204


will permit movement of the piston


184


or first mechanical object, adjacent T-piston


191


, and the hollow rod


186


until the valve trigger


200


is rotated to stop movement of the hydraulic fluid between the first and second hydraulic fluid chambers


202


,


204


. The mechanical valve trigger


200


may be any known trigger means for operating a valve including manual, mechanical, electro-mechanical, pneumatic, apparatus, etc. Additionally, in the illustrated embodiment, the mechanical valve trigger


220


is placed outside of the pneumatic fluid container


182


. However, the trigger


220


may be integrated within the container


182


for electro-mechanical actuation, etc.




It is noted that a pneumatic void


220


is defined between the piston


184


or first mechanical object and the T-piston


191


. The action of the T-piston


191


and pneumatic void


220


aid in compensating for volume changes that occur as the hydraulic fluid flows from the second non-compressible or hydraulic fluid chamber


202


into the first hydraulic fluid chamber


204


as the hollow rod


186


moves away from the first end seal


187


. The void


220


within the piston


184


is dimensioned to allow movement of the T-piston along the hollow rod


186


in order to compensate for a volume change of the second hydraulic fluid chamber


204


occupied by the stem sleeve


211


and valve stem


198


of the mechanical valve hydraulic fluid controller


194


. Because the second hydraulic chamber


204


within the hollow rod


186


includes the stem sleeve


211


, the volume change within the second hydraulic chamber


204


will be different than a volume change within the first hydraulic fluid chamber


202


hollow rod


186


which does not include the stem sleeve


211


. As the hydraulic fluid moves into the first hydraulic chamber


202


from the second hydraulic chamber


204


, the T-piston


191


is drawn into a compensating throughbore


221


defined within the first mechanical object or piston


184


. As the T-piston


191


fills the compensating throughbore


221


, the pneumatic void


220


and the second hydraulic fluid chamber


204


decrease in volume. The T-piston


191


may be replaced by its stem portion as a sliding seal within the compensating throughbore


221


in alternative embodiments.




The T-piston


191


or sliding seal is secured with respect to the first mechanical object or piston


184


by a partial vacuum generated by movement of the hydraulic fluid and the seal


195


between the T-piston and the compensating throughbore


221


of the piston


184


. The partial vacuum will cause the T-piston


191


to move closer to the piston


184


and into the compensating throughbore


221


or further away from the piston


184


, thus causing the pneumatic void


220


to increase or decrease in volume. To prevent any excess build up of air in the pneumatic void


220


, a reed valve


193


is secured within the piston


184


in fluid communication between the pneumatic void


220


and the second pneumatic chamber


192


to permit any air build up between the piston


184


and the T-piston


191


to be released from the pneumatic void


220


into the second pneumatic fluid chamber


192


.




Extended movement of the hollow rod


186


so that the rod adaptor


185


is at its farthest extension away from the second end seal


189


will create a need for more non-compressible fluid in the first hydraulic fluid chamber


202


and less non-compressible fluid in the second hydraulic fluid chamber


204


. Because of the vacuum formed by the seal


195


within the compensating throughbore


121


of the piston


184


, the T-piston will be drawn into the compensating throughbore


121


, thereby decreasing the volume of the pneumatic void


220


. As the rod adaptor


185


is moved back toward the second end


189


, the volume of non-compressible fluid occupying the first hydraulic fluid chamber


202


will move into the second hydraulic fluid chamber


204


. Because the second hydraulic fluid chamber


204


includes the stem sleeve


211


, a compensating volume expansion of that chamber


204


will be required, which is provided for by movement of the T-piston out of the compensating throughbore


121


within the first mechanical object or piston


184


. Movement of the T-piston


191


out of and away from the piston


184


increases the volume of the pneumatic void


220


, and air is admitted into the pneumatic void


220


through the reed valve


193


. Change in the volume of the pneumatic void


220


will not effect the accuracy, movement rate or positioning of the adaptor


185


as the mechanically valved embodiment


180


of the bi-fluid actuator is being utilized.




It can be seen that the above described dual rod embodiment of

FIG. 1

, single rod embodiment of

FIG. 2

, rodless piston embodiment of

FIG. 3

, rodless valved piston embodiment of

FIG. 4

, rotary embodiment of

FIG. 5

, rotary vane embodiment of

FIG. 6

, and the mechanically valved embodiment of

FIG. 7

all show bi-fluid actuators that rely upon a common principle of using a pneumatic, compressible fluid to power movement of a mechanical object or load carriage while simultaneously integrating within the same apparatus use of a non-compressible, hydraulic fluid to precisely control that pneumatically powered movement of the mechanical object. Because the hydraulic fluid is used primarily to control position and rate of movement of the mechanical object rather than powering such movement, the hydraulic fluid does not have to be pumped or controlled with large compressors and high pressure hoses, etc. Additionally, because the primary force is supplied by a compressed pneumatic fluid, such as freely available air, the bi-fluid actuator does not present cost, service and hazardous materials risks of known hydraulic and electronic actuators.




While the bi-fluid actuator has been disclosed with respect to the above described and illustrated embodiments, it is to be understood that the invention is not to be limited to those described and illustrated embodiments. For example, it is within the scope of the invention that the pneumatic, hydraulic and positioning controllers of any particular embodiment may themselves be controlled by or be integrated with a computerized overall controller means known in the art. Also, the single rod embodiment of

FIG. 2

, the rodless piston embodiment of

FIG. 3

, and the rodless, valved piston embodiment of

FIG. 4

, are all described above as having pneumatic fluid containers that surround, or partially surround their respective hydraulic fluid containers. However, it is within the scope of the present invention that those embodiments may simply have pneumatic fluid containers that are coaxial with hydraulic fluid containers, so that the pneumatic fluid containers are at least partially surrounded by respective hydraulic fluid containers. Moreover, specific components of the described embodiments of

FIGS. 1-7

may be utilized with other described embodiments. For example, the two-way, spring pre-set valve hydraulic fluid controller


118


of the

FIG. 4

rodless valved piston, may be utilized as the hydraulic fluid controller of the other embodiments. A two-way, spring pre-set valve means may be secured in fluid communication with the second mechanical objects that are secured between the first and second hydraulic fluid chambers of the

FIGS. 1-7

embodiments. Alternatively, a two-way spring pre-set valve means may actually be secured within the second mechanical objects of the embodiments shown in

FIGS. 1-3

,


6


, and


7


, as with the

FIG. 4

rodless valved piston embodiment.




Additionally, the phrases “pneumatic fluid” and “hydraulic fluid” are not to be limited to simply “air” and known hydraulic fluids, such as hydrocarbon based oils. Rather, the phrase “pneumatic fluid” is meant to include any compressible fluid, and the phrase “hydraulic fluid” is meant to include any non-compressible fluid, including, for example, water, known antifreeze solutions, etc. Further, while the above description characterizes the “pneumatic fluid controller” as directing pressurized or compressed pneumatic fluid into either first or second pneumatic chambers to power movement of the first mechanical object between the chambers, it is to be understood that the phrase “pneumatic fluid controller that selectively directs the pneumatic fluid” may also include application of a partial vacuum to either pneumatic chambers to thereby generate a pressure differential to power the first mechanical object, such as in circumstances of moving small mass loads. Accordingly, reference should be made primarily to the attached claims rather than to the foregoing description to determine the scope of the invention.



Claims
  • 1. A single rod bi-fluid actuator for precise bi-directional movement and positioning of a load, comprising:a. a pneumatic fluid container defining a first pneumatic fluid chamber and an opposed second pneumatic fluid chamber, the pneumatic fluid chambers containing a compressible, pneumatic fluid; b. a hydraulic fluid container defining a first hydraulic fluid chamber and an opposed second hydraulic fluid chamber, the hydraulic fluid chambers containing a non-compressible, hydraulic fluid; c. a first mechanical object positioned between the first and opposed second pneumatic fluid chambers so that the first mechanical object may be impacted and moved by the pneumatic fluid within the first or second pneumatic chambers; d. a second mechanical object linked to the first mechanical object and positioned between the first and opposed second hydraulic fluid chambers so that the second mechanical object may be impacted and positioned by the hydraulic fluid; e. a pneumatic fluid controller that selectively directs the pneumatic fluid into either the first or second pneumatic chamber of the pneumatic fluid container to expand the volume of the pneumatic fluid chamber that receives the pneumatic fluid; and, f. a hydraulic fluid controller that selectively permits, controls a rate of, or terminates passage of the hydraulic fluid between the first and the opposed second hydraulic fluid chambers of the hydraulic fluid container, so that the pneumatic fluid controller selectively powers the first and linked second mechanical objects to move in either a first or opposed second direction, and the hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the second and linked first mechanical objects in the first or opposed second direction by selectively permitting, controlling a rate of, or terminating passage of the hydraulic fluid between the first and second hydraulic fluid chambers of the hydraulic fluid container and; g. single rod bi-fluid actuator having the pneumatic fluid container secured in coaxial relationship with the hydraulic fluid container, having the first mechanical object coaxial with the hydraulic fluid container, having a rod secured to the first mechanical object and extending out of the pneumatic fluid container to be secured to the load, and having a hydraulic fluid reservoir tube secured adjacent to the hydraulic fluid container and in fluid communication through a hydraulic fluid reservoir opening with the hydraulic fluid container and the hydraulic fluid controller so that the first mechanical object is coaxial with the hydraulic fluid container and hydraulic fluid reservoir tube.
  • 2. The bi-fluid actuator of claim 1, wherein the hydraulic controller is a two-way, spring pre-set valve means for permitting and terminating two-way flow of a non-compressible fluid through the valve in response to pressure changes acting upon the valve and the valve means is secured within the second mechanical object.
  • 3. A rodless piston bi-fluid actuator for precise bi-directional movement and positioning of a load, comprising:a. a pneumatic fluid container defining a first pneumatic fluid chamber and an opposed second pneumatic fluid chamber, the pneumatic fluid chambers containing a compressible, pneumatic fluid; b. a hydraulic fluid container defining a first hydraulic fluid chamber and an opposed second hydraulic fluid chamber, the hydraulic fluid chambers containing a non-compressible, hydraulic fluid; c. a first mechanical object positioned between the first and opposed second pneumatic fluid chambers so that the first mechanical object may be impacted and moved by the pneumatic fluid within the first or second pneumatic chambers; d. a second mechanical object linked to the first mechanical object and positioned between the first and opposed second hydraulic fluid chambers so that the second mechanical object may be impacted and positioned by the hydraulic fluid; e. a pneumatic fluid controller that selectively directs the pneumatic fluid into either the first or second pneumatic chamber of the pneumatic fluid container to expand the volume of the pneumatic fluid chamber that receives the pneumatic fluid; and, f. a hydraulic fluid controller that selectively permits, controls a rate of, or terminates passage of the hydraulic fluid between the first and the opposed second hydraulic fluid chambers of the hydraulic fluid container, so that the pneumatic fluid controller selectively powers the first and linked second mechanical objects to move in either a first or opposed second direction, and the hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the second and linked first mechanical objects in the first or opposed second direction by selectively permitting, controlling a rate of, or terminating passage of the hydraulic fluid between the first and second hydraulic fluid chambers of the hydraulic fluid container and; g. rodless piston bi-fluid actuator, having the pneumatic fluid container in coaxial relationship with the hydraulic fluid container, having the first mechanical object coaxial with the hydraulic fluid container, and having a load carriage linked to the first mechanical object and secured adjacent to the pneumatic fluid container so that movement of the first and second mechanical objects moves the load carriage.
  • 4. The bi-fluid actuator of claim 3 wherein the hydraulic controller is a two-way, spring pre-set valve means secured within the second mechanical object for permitting and terminating two-way flow of a non-compressible fluid through the valve in response to pressure changes acting upon the valve, so that hydraulic fluid may flow through the valve and second mechanical object to permit movement of the second mechanical object and linked first mechanical object whenever pneumatic fluid that is pressurized to a valve override pressure is directed by the pneumatic controller to one of the pneumatic fluid chambers.
  • 5. A rotary bi-fluid actuator for precise bi-directional movement and positioning of a load, comprising:a. a pneumatic fluid container defining a first pneumatic fluid chamber and an opposed second pneumatic fluid chamber, the pneumatic fluid chambers containing a compressible, pneumatic fluid; b. a hydraulic fluid container defining a first hydraulic fluid chamber and an opposed second hydraulic fluid chamber, the hydraulic fluid chambers containing a non-compressible, hydraulic fluid; c. a first mechanical object positioned between the first and opposed second pneumatic fluid chambers so that the first mechanical object may be impacted and moved by the pneumatic fluid within the first or second pneumatic chambers; d. a second mechanical object linked to the first mechanical object and positioned between the first and opposed second hydraulic fluid chambers so that the second mechanical object may be impacted and positioned by the hydraulic fluid; e. a pneumatic fluid controller that selectively directs the pneumatic fluid into either the first or second pneumatic chamber of the pneumatic fluid container to expand the volume of the pneumatic fluid chamber that receives the pneumatic fluid; and, f. a hydraulic fluid controller that selectively permits, controls a rate of, or terminates passage of the hydraulic fluid between the first and the opposed second hydraulic fluid chambers of the hydraulic fluid container, so that the pneumatic fluid controller selectively powers the first and linked second mechanical objects to move in either a first or opposed second direction, and the hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the second and linked first mechanical objects in the first or opposed second direction by selectively permitting, controlling a rate of, or terminating passage of the hydraulic fluid between the first and second hydraulic fluid chambers of the hydraulic fluid container and; g. wherein the pneumatic fluid container is a first deformable tube, the hydraulic fluid container is a second deformable tube secured adjacent to the first deformable tube, the first and second deformable tubes being secured within an at least partially cylindrical housing so that the first and second deformable tubes define at least a portion of a circle, the first mechanical object is a first pinch roller secured to an armature, the second mechanical object is a second pinch roller secured to the armature, the first pinch roller being secured by the armature against the first deformable tube to deform the tube into defining the first and second pneumatic chambers on opposed sides of the first pinch roller, the second pinch roller being linked to the first pinch roller and being secured by the armature against the second deformable tube to deform the tube into defining the first and second hydraulic chambers on opposed sides of the second pinch roller, so that pneumatic fluid within one of the pneumatic fluid chambers will power the first pinch roller, and movement of hydraulic fluid through the hydraulic fluid controller between the hydraulic fluid chambers will permit rotation of the second and linked first pinch rollers and armature.
  • 6. A rotary vane bi-fluid actuator for precise bi-directional movement and positioning of a load, comprising:a. a pneumatic fluid container defining a first pneumatic fluid chamber and an opposed second pneumatic fluid chamber, the pneumatic fluid chambers containing a compressible, pneumatic fluid; b. a hydraulic fluid container defining a first hydraulic fluid chamber and an opposed second hydraulic fluid chamber, the hydraulic fluid chambers containing a non-compressible, hydraulic fluid; c. a first mechanical object positioned between the first and opposed second pneumatic fluid chambers so that the first mechanical object may be impacted and moved by the pneumatic fluid within the first or second pneumatic chambers; d. a second mechanical object linked to the first mechanical object and positioned between the first and opposed second hydraulic fluid chambers so that the second mechanical object may be impacted and positioned by the hydraulic fluid; e. a pneumatic fluid controller that selectively directs the pneumatic fluid into either the first or second pneumatic chamber of the pneumatic fluid container to expand the volume of the pneumatic fluid chamber that receives the pneumatic fluid; and, f. a hydraulic fluid controller that selectively permits, controls a rate of, or terminates passage of the hydraulic fluid between the first and the opposed second hydraulic fluid chambers of the hydraulic fluid container, so that the pneumatic fluid controller selectively powers the first and linked second mechanical objects to move in either a first or opposed second direction, and the hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the second and linked first mechanical objects in the first or opposed second direction by selectively permitting, controlling a rate of, or terminating passage of the hydraulic fluid between the first and second hydraulic fluid chambers of the hydraulic fluid container and; g. wherein the pneumatic container is a half cylinder, the hydraulic container is an opposed half cylinder defined within a cylindrical housing, the pneumatic and hydraulic containers are separated by a non-rotating containment wall, the first mechanical object is a first half vane within the pneumatic container that divides the pneumatic container into the opposed first and second pneumatic fluid chambers, the second mechanical object is a second half vane within the hydraulic container that divides the hydraulic container into the opposed first and second hydraulic fluid chambers, and the first and second half vanes are linked to each other so that pressurized pneumatic fluid within one of the pneumatic fluid chambers will power the first half vane, and movement of the hydraulic fluid through the hydraulic fluid controller between the first and second hydraulic chambers permits movement of the first half vane and second half vane.
  • 7. A mechanically valved bi-fluid actuator for precise bi-directional movement and positioning of a load, comprising:a. a pneumatic fluid container defining a first pneumatic fluid chamber and an opposed second pneumatic fluid chamber, the pneumatic fluid chambers containing a compressible, pneumatic fluid; b. a first mechanical object positioned between the first and opposed second pneumatic fluid chambers so that the first mechanical object may be impacted and moved by the pneumatic fluid within the pneumatic fluid chambers, the first mechanical object including a piston and hollow rod secured to the piston that passes out of the pneumatic fluid container for securing the hollow rod to the load, and the first mechanical object including a sliding seal adjustably secured adjacent to the piston so the sliding seal may move into and out of a compensating throughbore of the piston as the piston and sliding seal move within the pneumatic container; c. a hydraulic fluid container defined within the hollow rod of the first mechanical object and defining a first hydraulic fluid chamber and an opposed second hydraulic chamber, the chambers containing a non-compressible, hydraulic fluid; d. a mechanical valve hydraulic fluid controller including a second mechanical object rotational port valve assembly secured by a valve stem within the hydraulic container between the first and second hydraulic chambers, the valve stem also including a valve trigger secured to the valve stem, so that movement of the valve trigger rotates a rotational valve port plate to permit or terminate passage of the hydraulic fluid through the rotational port valve assembly between the first and second hydraulic fluid chambers; and, e. a pneumatic fluid controller that selectively directs the pneumatic fluid into either the first or second pneumatic chamber of the pneumatic fluid container to expand the volume of the pneumatic fluid chamber that receives the pneumatic fluid, so that the pneumatic fluid controller selectively powers the first mechanical object to move in either a first or opposed second direction, and the mechanical valve hydraulic fluid controller selectively permits movement and controls a rate of movement and position of the first mechanical object by selectively permitting, controlling a rate of, and terminating passage of the hydraulic fluid between the first and second hydraulic fluid chambers of the hydraulic fluid container.
  • 8. The mechanically valved bi-fluid actuator of claim 7, further comprising a positioning controller means for detecting a position of the load secured to the rod of the first mechanical object.
  • 9. A method of moving, controlling a rate of movement, and positioning a load, comprising the steps of:a. directing a pneumatic fluid into either a first or second pneumatic fluid chamber of a dual rod bi-fluid actuator, the first or second pneumatic fluid chambers being defined within a pneumatic fluid container of the dual rod bi-fluid actuator, which first and second pneumatic chambers are disposed on opposed sides of a first mechanical object; b. controlling passage of a hydraulic fluid between a first hydraulic fluid chamber and a second hydraulic fluid chamber defined within a hydraulic fluid container of the dual rod bi-fluid actuator to permit or terminate passage of the fluid between the first and second hydraulic fluid chambers in order to control movement and positioning of a second mechanical object, which second mechanical object is secured between the first and second hydraulic fluid chambers and is also linked to the first mechanical object, and which first mechanical object is secured to the load; and, c. detecting a position of the load with a positioning controller as the load is moved and communicating the detected position to a hydraulic fluid controller that controls the passage of the hydraulic fluid between the first and second hydraulic fluid chambers.
  • 10. A method of moving, controlling a rate of movement, and positioning a load, comprising the steps of:a. directing a pneumatic fluid into either a first or second pneumatic fluid chamber of a single rod bi-fluid actuator, the first or second pneumatic fluid chambers being defined within a pneumatic fluid container of the single rod bi-fluid actuator, which first and second pneumatic chambers are disposed on opposed sides of a first mechanical object; b. controlling passage of a hydraulic fluid between a first hydraulic fluid chamber and a second hydraulic fluid chamber defined within a hydraulic fluid container and through a hydraulic fluid reservoir tube secured adjacent and parallel to the hydraulic fluid container of the single rod bi-fluid actuator to permit or terminate passage of the fluid between the first and second hydraulic fluid chambers in order to control movement and positioning of a second mechanical object, which second mechanical object is secured between the first and second hydraulic fluid chambers and is also linked to the first mechanical object and which first mechanical object is secured to the load; and, c. detecting a position of the load with a positioning controller as the load is moved and communicating the detected position to a hydraulic fluid controller that controls the passage of the hydraulic fluid between the first and second hydraulic fluid chambers.
  • 11. A method of moving, controlling a rate of movement, and positioning a load, comprising the steps of:a. directing a pneumatic fluid into either a first or second pneumatic fluid chamber of a rodless piston bi-fluid actuator, the first or second pneumatic fluid chambers being defined within a pneumatic fluid container of the rodless piston bi-fluid actuator, which first and second pneumatic chambers are disposed on opposed sides of a first mechanical object; b. controlling passage of a hydraulic fluid between a first hydraulic fluid chamber and a second hydraulic fluid chamber defined within a hydraulic fluid container of the rodless piston bi-fluid actuator to permit or terminate passage of the fluid between the first and second hydraulic fluid chambers in order to control movement and positioning of a second mechanical object, which second mechanical object is secured between the first and second hydraulic fluid chambers and is also linked to the first mechanical object, and which first mechanical object is secured to the load; and, c. detecting a position of the load with a positioning controller as the load is moved and communicating the detected position to a hydraulic fluid controller that controls the passage of the hydraulic fluid between the first and second hydraulic fluid chambers.
  • 12. The method of claim 11, wherein the step of directing a pneumatic fluid further comprises directing the pneumatic fluid into the first or second pneumatic fluid chamber of a rodless valved piston bi-fluid actuator.
  • 13. A method of moving, controlling a rate of movement, and positioning a load, comprising the steps of:a. directing a pneumatic fluid into either a first or second pneumatic fluid chamber of a rotary bi-fluid actuator, the first or second pneumatic fluid chambers being defined within a deformable tube pneumatic fluid container of the rotary bi-fluid actuator, which first and second pneumatic chambers are disposed on opposed sides of a pinch roller first mechanical object; b. controlling passage of a hydraulic fluid between a first hydraulic fluid chamber and a second hydraulic fluid chamber defined within a deformable tube hydraulic fluid container of the rotary bi-fluid actuator to permit or terminate passage of the fluid between the first and second hydraulic fluid chambers in order to control movement and positioning of a second pinch roller mechanical object, which second mechanical object is secured between the first and second hydraulic fluid chambers and is also linked to the first mechanical object, and which first mechanical object is secured to the load; and, c. detecting a position of the load with a positioning controller as the load is moved and communicating the detected position to a hydraulic fluid controller that controls the passage of the hydraulic fluid between the first and second hydraulic fluid chambers.
CROSS REFERENCE TO RELATED APPLICATION

This Application claims the benefit of U.S. Provisional Application Serial No. 60/289,774 filed on May 9, 2001.

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Foreign Referenced Citations (1)
Number Date Country
11-158065 Dec 2000 JP
Provisional Applications (1)
Number Date Country
60/289774 May 2001 US