Linear working apparatus

Information

  • Patent Grant
  • 6308821
  • Patent Number
    6,308,821
  • Date Filed
    Friday, April 14, 2000
    24 years ago
  • Date Issued
    Tuesday, October 30, 2001
    23 years ago
Abstract
A rail member and a rodless cylinder are arranged closely substantially in parallel to one another, and shock absorbers and the rail member are arranged closely substantially in parallel to one another. Accordingly, it is possible to arrange, in an ideal layout, the three components of the rail member, the rodless cylinder, and the shock absorbers. Further, it is possible to realize a compact size of the entire apparatus.
Description




BACKGROUND OF THE INVENTION




1. Field of the Invention




The present invention relates to a linear working apparatus which functions, for example, as a workpiece transport means by operating a slider in a reciprocating manner.




2. Description of the Related Art




In recent years, a variety of linear working machines including, for example, rodless cylinders are adopted as workpiece transport means in the factory or the like. Such a linear working machine concerning the conventional technique is shown in

FIG. 9

(see Japanese Laid-Open Patent Publication No. 9-177717).




The linear working machine


1


includes a base plate


2


which has a flat plate-shaped configuration, a pair of end blocks


3




a


,


3




b


which are connected to both ends in the axial direction of the base plate


2


, and a rodless cylinder


4


which is fixed between the end blocks


3




a


,


3




b.






A guide rail


5


, which is disposed substantially in parallel to the axis of the rodless cylinder


4


, is fixed to the base plate


2


. A pair of shock absorbers


6




a


,


6




b


are arranged opposingly substantially in parallel to the axis of the rodless cylinder


4


between the guide rail


5


and the rodless cylinder


4


. A slide table


7


, which makes linear reciprocating movement along the guide rail


5


in accordance with the driving action of the rodless cylinder


4


, is provided on the base plate


2


.




However, in the case of the linear working machine


1


concerning the conventional technique described above, the pair of shock absorbers


6




a


,


6




b


are interposed between the rodless cylinder


4


and the guide rail


5


which are arranged substantially in parallel to one another. Therefore, a problem arises in that the distance of separation is inevitably increased between the rodless cylinder


4


and the guide rail


5


.




That is, when the kinetic energy (thrust force) is transmitted from the rodless cylinder


4


to the slide table


7


in order to start the movement of the slide table


7


, the reaction force is generated on the guide rail


5


on which the slide table


7


is displaced. The larger the separation distance between the rodless cylinder


4


and the guide rail


5


is, the more the reaction force is increased. In other words, the smaller the separation distance between the rodless cylinder


4


and the guide rail


5


is, the more the reaction force is repressed. Therefore, ideally, it is desirable that the rodless cylinder


4


and the guide rail


5


are arranged as closely to one another as possible.




When the shock absorber


6




a


,


6




b


absorbs the impact force at the terminal end of the displacement of the slide table


7


, the reaction force of the shock absorber


6




a


,


6




b


is applied to the guide rail


5


. The larger the separation distance between the shock absorbers


6




a


,


6




b


and the guide rail


5


is, the more the reaction force is increased. Therefore, in order to suppress the reaction force applied to the guide rail


5


, ideally, it is desirable that the shock absorbers


6




a


,


6




b


and the guide rail


5


are arranged as closely to one another as possible.




SUMMARY OF THE INVENTION




A general object of the present invention is to provide a linear working apparatus comprising three components of a driving mechanism, a track mechanism, and a buffering mechanism which are arranged in an ideal layout, making it possible to realize a compact size of the entire apparatus.




The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which a preferred embodiment of the present invention is shown by way of illustrative example.











BRIEF DESCRIPTION OF THE DRAWINGS





FIG. 1

shows a perspective view illustrating a linear working apparatus according to an embodiment of the present invention;





FIG. 2

shows an exploded perspective view illustrating a base plate and a rodless cylinder for constructing the linear working apparatus;





FIG. 3

shows a plan view illustrating the linear working apparatus shown in

FIG. 1

;





FIG. 4

shows a cross-sectional view taken along a line IV—IV shown in

FIG. 1

;





FIG. 5

shows a perspective view illustrating a piston for constructing the rodless cylinder;





FIG. 6

shows, with partial omission, a magnified perspective view illustrating a shock absorber;





FIG. 7

shows, with partial omission, a longitudinal sectional view illustrating an engaging state of a first seal member and a slit;





FIG. 8

shows, with partial omission, a longitudinal sectional view taken along a line VIII—VIII shown in

FIG. 3

; and





FIG. 9

shows a perspective view illustrating a linear working machine concerning the conventional technique.











DESCRIPTION OF THE PREFERRED EMBODIMENTS




In

FIG. 1

, reference numeral


10


indicates a linear working apparatus according to an embodiment of the present invention.




The linear working apparatus


10


comprises a base plate (base member)


12


which has a flat plate-shaped configuration, a pair of end blocks


14




a


,


14




b


which are connected to both ends in the axial direction of the base plate


12


respectively, a linear guide mechanism (track mechanism)


16


which is secured in the axial direction to a substantially central portion of the base plate


12


, and a slider


20


which is formed with a substantially flat workpiece attachment surface


18


on its upper surface and which makes reciprocating movement in the axial direction of the base plate


12


along the linear guide mechanism


16


. The workpiece attachment surface


18


of the slider


20


may be used in any way including, for example, a case in which an unillustrated workpiece is directly attached thereto or placed thereon, and a case in which the workpiece is indirectly attached thereto or placed thereon by the aid of any member.




The linear working apparatus


10


further comprises a rodless cylinder (driving mechanism)


24


which is connected to a side portion of the base plate


12


by the aid of attachment mechanisms


22


and which is arranged substantially in parallel to the linear guide mechanism


16


, and a pair of shock absorbers (buffering mechanisms)


26




a


,


26




b


which are arranged opposingly on a side opposite to the rodless cylinder


24


with the linear guide mechanism


16


interposed therebetween. A sensor attachment long groove


28


having a rectangular cross section is formed in the axial direction on a side of the base plate


12


opposite to the side on which the rodless cylinder


24


is connected. The shock absorbers


26




a


,


26




b


function such that the terminal end of the displacement of the slider


20


is regulated, and the shock applied to the slider


20


is absorbed.




The linear guide mechanism


16


has a lengthy rail member


30


which is secured to an upper surface portion of the base plate


12


by the aid of screw members, and a pair of guide blocks (sliding members)


32


which are slidably displaceable along the rail member


30


in accordance with the rolling action of a plurality of unillustrated ball bearings. The slider


20


is secured to the upper surfaces of the pair of guide blocks


32


by the aid of screw members. The slider


20


is provided displaceably along the rail member


30


by the aid of the guide blocks


32


. A plurality of unillustrated roller members (rolling members) having a cylindrical configuration are provided rollably on a bottom surface portion of the slider


20


in place of the guide blocks


32


so that the slider


20


may be displaced along the rail member


30


in accordance with the rolling action of the roller members.




As shown in

FIG. 6

, the shock absorber


26




a


,


26




b


is fixed to the base plate


12


by the aid of a block member


34


. A screw member


38


for controlling the buffering force is provided through the end block


14




a


,


14




b


with a cutout


36


having a semielliptic cross section. In this arrangement, the pair of shock absorbers


26




a


,


26




b


are arranged opposingly by being separated from each other by a predetermined spacing distance, and they are arranged such that a phantom line obtained by connecting the pair of shock absorbers


26




a


,


26




b


is substantially parallel to the axis of the rail member


30


. The pair of shock absorbers


26




a


,


26




b


are arranged as closely as possible with respect to the rail member


30


.




As shown in

FIG. 2

, the attachment mechanism


22


for detachably connecting the base plate


12


and the rodless cylinder


24


is provided at the connecting portion between the end block


14




a


,


14




b


and the rodless cylinder


24


. The attachment mechanism


22


includes a recess


40


which is formed on the end block


14




a


,


14




b


, a projection


44


which is provided on an end cap


42




a


,


42




b


of the rodless cylinder


24


and which is connected to the recess


40


, and screw members


46


for fastening the projection


44


to the recess


40


by means of screws. In this arrangement, the screw members


46


are provided so that they may be screwed in a direction substantially perpendicular to the workpiece attachment surface


18


of the slider


20


(from an upward position).




A positioning mechanism


48


is provided at the connecting portion between the end block


14




a


(


14




b


) and the rodless cylinder


24


. The positioning mechanism


48


includes a small hole


50


which is formed on one side surface of the end block


14




a


(


14




b


), and a projection


52


which protrudes outwardly from the end cap


42




a


(


42




b


) of the rodless cylinder


24


. In this arrangement, the base plate


12


and the rodless cylinder


24


are connected in a positioned state by inserting the projection


52


into the small hole


50


.




A pair of end plates


54




a


,


54




b


, which extend in a direction substantially perpendicular to the axis, are connected to both ends of the slider


20


. The end plate


54




a


,


54




b


has an engaging section


58


which protrudes laterally from the end surface of the slider


20


for making engagement with a piston yoke


56




a


,


56




b


(see

FIG. 5

) as described later on, and a substantially flat abutment surface


60


for making abutment against the shock absorber


26




a


,


26




b.






As shown in

FIG. 8

, the rodless cylinder


24


has a cylinder tube


64


with a slit


62


which is formed at an end surface portion, the slit


62


extending in the axial direction. A bore


66


, which extends in the longitudinal direction, is provided at the inside of the cylinder tube


64


. The bore


66


is in a state of communication with the outside via the slit


62


which is formed at the end surface portion of the cylinder tube


64


.




Both ends of the cylinder tube


64


are closed in an air-tight manner by the rectangular parallelepiped-shaped end caps


42




a


,


42




b


(see

FIG. 1

) which are formed with a pair of pressure fluid inlet/outlet ports


68


respectively. Step sections


70




a


,


70




b


, which are expanded toward the bore


66


, are provided on side walls for forming the slit


62


(see FIG.


7


).





FIG. 5

shows a piston


72


. The piston


72


has a main piston body


74


having a substantially cylindrical configuration. A first pressure-receiving surface


76


is formed at one end of the main piston body


74


in the axial direction, and a second pressure-receiving surface


78


is formed on a side opposite thereto. A cushion seal


80


is provided at the inside thereof. A pair of belt separators


86


for separating a first seal member


82


from a second seal member


84


as described later on are arranged opposingly in the axial direction on the cylindrical main piston body


74


. A parallel pin


88


, which slidably contacts with the second seal member


84


, is provided at a central portion between the pair of belt separators


86


.




The main piston body


74


has the pair of piston yokes (displacement members)


56




a


,


56




b


which are formed in an integrated manner in the axial direction. The piston yokes


56




a


,


56




b


are provided so that they are engaged with the engaging sections


58


of the pair of end plates


54




a


,


54




b


of the slider


20


. As shown in

FIG. 4

, a flat plate-shaped top cover


90


is installed to the pair of piston yokes


56




a


,


56




b


. A pair of end covers


92


, which extend in a direction substantially perpendicular to the axis, are installed to both ends of the piston yokes


56




a


,


56




b


respectively. A scraper


94


is held via a groove on one narrow side surface of the end cover


92


. The scraper


94


slidably contacts with the second seal member


84


, and thus any dust or the like is removed.




As shown in

FIG. 8

, recesses, which extend in the axial direction, are formed on side surface portions in the lateral direction of the pair of piston yokes


56




a


,


56




b


. A pair of lengthy bearing members


96


, which are made of a resin material and which slidably contact with the side surface of the cylinder tube


64


to support the piston


72


, are installed to the recesses. The provision of the bearing members


96


makes it possible to avoid rotation of the piston


72


and avoid any contact between the piston yokes


56




a


,


56




b


and the cylinder tube


64


.




In

FIG. 4

, reference numeral


98


indicates a passage for the first seal member


82


to enter the inside of the piston


72


, and reference numeral


100


indicates cushion rings connected to the end caps


42




a


,


42




b.







FIG. 7

shows the seal member for being fitted to the step sections


70




a


,


70




b


which are formed at the slit


62


of the cylinder tube


64


. The first seal member


82


has tongues


102




a


,


102




b


, and it further includes expanded sections


104




a


,


104




b


which are disposed in the lateral direction of the tongues


102




a


,


102




b


. Engaging tabs


106




a


,


106




b


extend laterally from the expanded sections


104




a


,


104




b


to make slight expansion. The expanded sections


104




a


,


104




b


are provided in order that they make engagement with the step sections


70




a


,


70




b


when the internal pressure is applied to the piston


72


. The engaging tabs


106




a


,


106




b


are engaged with inner surfaces


108




a


,


108




b


for forming the slit


62


. The first seal member


82


is made of a flexible synthetic resin material in an integrated manner as a whole.




On the other hand, the second seal member


84


is provided in order to close the slit


62


. The second seal member


84


is engaged with a groove


110


which extends in the longitudinal direction on the side surface of the cylinder tube


64


. The first seal member


82


enters the inside of the passage


98


of the piston


72


, and it has both ends which are secured to the end caps


42




a


,


42




b


together with the second seal member


84


.




The linear working apparatus


10


according to the embodiment of the present invention is basically constructed as described above. Next, its operation, function, and effect will be explained.




When the compressed air is introduced from the first pressure fluid inlet/outlet port


68


formed on the end cap


42


, then the compressed air passes through the passage formed at the inside of the cushion ring


100


, and it presses the first pressure-receiving surface


76


. The piston


72


is displaced rightwardly (in the direction of the arrow X) as viewed in

FIG. 4

in accordance with the pressing action of the compressed air. During this process, the piston


72


is displaced integrally with the pair of piston yokes


56




a


,


56




b


. The belt separator


86


functions to separate the first seal member


82


from the second seal member


84


when the piston yokes


56




a


,


56




b


are displaced.




When the piston yokes


56




a


,


56




b


are displaced in the longitudinal direction of the cylinder tube


64


, the slider


20


is displaced integrally with the piston yokes


56




a


,


56




b


in accordance with the guiding action of the rail member


30


by the aid of the pair of end plates


54




a


,


54




b


which are substantially engaged with the piston yokes


56




a


,


56




b.






The pin of the shock absorber


26




a


(


26




b


) abuts against the abutment surface


60


formed on the end plate


54




a


(


54




b


) of the slider


20


to arrive at the displacement terminal position thereby. During this process, the shock generated upon the abutment is absorbed in accordance with the buffering action of the shock absorber


26




a


,


26




b.






On the other hand, when the compressed air is introduced into the second pressure fluid inlet/outlet port


68


formed on the end cap


42




a


, the operation is performed in a way opposite to the above.




In the embodiment of the present invention, the rodless cylinder


24


is arranged closely substantially in parallel to the axis of the rail member


30


with the rail member


30


disposed therebetween. The pair of shock absorbers


26




a


,


26




b


are arranged closely to be substantially parallel to the axis of the rail member


30


on the side opposite to the rodless cylinder


24


. In other words, with reference to the rail member


30


disposed substantially centrally, the rodless cylinder


24


and the shock absorbers


26




a


,


26




b


are arranged closely to be substantially parallel to one another on the both sides thereof.




Therefore, owing to the arrangement in which the rail member


30


and the rodless cylinder


24


are arranged closely substantially in parallel to one another, and the shock absorbers


26




a


,


26




b


and the rail member


30


are arranged closely substantially in parallel to one another, it is possible to arrange, in the ideal layout, the three components of the rail member


30


which functions as the track mechanism, the rodless cylinder


24


which functions as the driving mechanism, and the shock absorbers


26




a


,


26




b


which function as the buffering mechanism. Further, it is possible to realize a compact size of the entire apparatus. As a result, the load on the rail member


30


can be reduced and mitigated by suppressing the reaction force generated, for example, when the operation of the slider


20


is started.




In the embodiment of the present invention, the rodless cylinder


24


and the base plate


12


provided with the rail member


30


and the shock absorbers


26




a


,


26




b


are provided detachably by the aid of the attachment mechanism


22


. Accordingly, it is easy to exchange the driving mechanism. Further, it is possible to increase the degree of freedom of selection of the driving mechanism, and it is possible to improve the versatile property. In this arrangement, the screw member


46


, which is used to connect the base plate


12


and the rodless cylinder


24


, can be screwed from the upward position in the direction perpendicular to the workpiece attachment surface


18


of the slider


20


. Accordingly, the apparatus is advantageous in that the attachment and the detachment can be conveniently performed with ease.




The driving force of the rodless cylinder


24


can be transmitted to the slider


20


by allowing the piston yokes


56




a


,


56




b


to make the engagement between the engaging sections


58


of the pair of end plates


54




a


,


54




b


. Therefore, the driving force can be smoothly transmitted by using the simple arrangement. In this case, a predetermined clearance (not shown) is provided between the piston yoke


56




a


(


56




b


) and the engaging section


58


of the end plate


54




a


(


54




b


). The floating function to permit the displacement of the piston yoke


56




a


(


56




b


) is effected by the aid of the clearance.




The abutment surface


60


for making the abutment against the pin of the shock absorber


26




a


(


26




b


) is simultaneously provided on the end plate


54




a


(


54




b


) in addition to the engaging section


58


for making the engagement with the piston yoke


56




a


(


56




b


). Accordingly, it is possible to reduce the number of parts.




The embodiment of the present invention has been explained based on the use of the rodless cylinder


24


in which the piston


72


is displaced in accordance with the action of the pressure fluid as the driving mechanism. However, there is no limitation thereto. It is a matter of course that other driving mechanisms are usable, including, for example, a magnet type rodless cylinder in which an external movable member is displaced in accordance with the action of a magnet, a linear actuator which includes a fluid pressure-operated cylinder, and an electric actuator in which an external movable member is displaced in accordance with the transmission of a rotary driving force of a rotary driving source.



Claims
  • 1. A linear working apparatus comprising:a base member; a linear track mechanism secured to said base member in its axial direction; a slider for making reciprocating movement along said track mechanism; a driving mechanism arranged substantially in parallel to said axis of said track mechanism, for transmitting rectilinear motion to said slider; and a buffering mechanism arranged on a side opposite to said driving mechanism with said track mechanism interposed therebetween, for regulating a displacement terminal end of said slider and absorbing shock applied to said slider.
  • 2. The linear working apparatus according to claim 1, wherein said driving mechanism is provided detachably with respect to said base member by the aid of an attachment mechanism.
  • 3. The linear working apparatus according to claim 1, wherein said slider is provided with a pair of end plates for making engagement with displacement members of said driving mechanism for transmitting said rectilinear motion, and said end plate is formed with an abutment surface for making abutment against said buffering mechanism.
  • 4. The linear working apparatus according to claim 2, wherein said attachment mechanism includes a screw member for connecting said base member and said driving mechanism, and said screw member is capable of being screwed in a direction substantially perpendicular to a workpiece attachment surface of said slider.
  • 5. The linear working apparatus according to claim 2, wherein a positioning mechanism for connecting said base member and said driving mechanism in a positioned state is provided at a connecting portion between said base member and said driving mechanism.
  • 6. The linear working apparatus according to claim 1, wherein said driving mechanism is composed any one of a fluid pressure-operated rodless cylinder in which a piston is displaced in accordance with an action of a pressure fluid, a magnet type rodless cylinder in which an external movable member is displaced in accordance with an action of a magnet, a linear actuator, and an electric actuator.
  • 7. The linear working apparatus according to claim 1, wherein said track mechanism is composed of a linear guide mechanism, and said linear guide mechanism includes a lengthy rail member and a rolling member or a sliding member for making displacement along said rail member.
  • 8. The linear working apparatus according to claim 1, wherein said buffering mechanism is composed of a plurality of shock absorbers, and said shock absorbers are arranged substantially in parallel to said axis of said track mechanism at ends of said base member.
  • 9. The linear working apparatus according to claim 3, wherein a predetermined clearance is provided between said end plate and said displacement member, and a floating function to permit displacement of said displacement member is effected by the aid of said clearance.
  • 10. The linear working apparatus according to claim 5, wherein said positioning mechanism includes a small hole formed on one side surface of an end block connected to an end of said base member, and a projection protruding from an end cap of said driving mechanism, for being inserted into said small hole.
Priority Claims (1)
Number Date Country Kind
11-110158 Apr 1999 JP
US Referenced Citations (3)
Number Name Date Kind
5211279 Abbestam et al. May 1993
5469775 Stoll et al. Nov 1995
5484051 Nagai et al. Jan 1996
Foreign Referenced Citations (3)
Number Date Country
41 37 789 May 1993 DE
0 346 504 Dec 1989 EP
09-177717 Jul 1997 JP