Patent Application
20200208357
The present invention relates generally to slipform paving machines, and more particularly to offset slipform paving machines using relatively large molds having a variable mold height and variable internal cross-section.
It is known to use relatively large variable height offset molds for paving or forming variable height concrete barriers adjacent a highway. These molds include at least one form insert that is variable in height relative to a mold frame, as well as two side plates to vary the lower portions of the profile of the mold form. These existing machines vary the profile height of the mold form through the use of the lifting columns which support the paving machine. In some instances, the variable height of the mold exceeds the available leg stroke of the lifting columns. This problem has previously been addressed by stopping the paving operation when a maximum leg stroke is reached, then unbolting the mold from the machine and re-bolting it to the paving machine in a different position so that the legs of the paving machine can be lowered, and paving can be resume. This procedure requires a great deal of manual work. Additionally, when the position of the mold relative to the machine frame is changed, the position of the feeding auger or belt relative to the machine frame must also be changed.
A further complication is that it is undesirable to use the entire leg stroke of the paving machine for purposes of adjusting mold height. This is because these relatively large molds are very heavy and thus if the legs are extended to their maximum height, the paving machine may be unstable. Accordingly, only a portion of the leg stroke may be used, and this can require further stages of unbolting and reattaching the mold to the machine frame.
These prior art devices have typically required that at least one ground-based operator walk alongside the mold and manually adjust the position of the left and right side form inserts and/or the left and right side plates. In some situations, two ground-based operators may be required, one walking along each side of the form.
These existing machines may control the height of the machine frame, and thus the height of the attached offset mold, by following a stringline reference which has been constructed along side the path where the concrete barrier is to be constructed. It is also known to utilize a second stringline reference to control an elevation of one of the form inserts of the offset mold.
Accordingly, there is a need for improved slipform paving machines designed to improve the use of large variable height offset molds.
In one embodiment a slipform paving machine includes a machine frame, and a plurality of ground engaging units for supporting the slipform paving machine from a ground surface. A plurality of height adjustable machine frame supports may support the machine frame from the plurality of ground engaging units. Each of the machine frames supports may include a machine frame support actuator configured to adjust a height of the machine frame relative to a respective one of the ground engaging units. Each of the machine frame supports may include a machine frame support sensor configured to provide a signal corresponding to the height of the machine frame relative to the respective one of the ground engaging units. The paving machine further includes an offset mold including a mold frame. A mold frame actuator may be configured to adjust a height of the mold frame relative to the machine frame. A mold frame sensor may be configured to provide a signal corresponding to the height of the mold frame relative to the machine frame. An external reference sensor may be provided and configured to provide a signal representative of a position of the slipform paving machine relative to an external reference system. The machine may include a controller configured to receive the signal from the external reference sensor, and to control extension of machine frame support actuators and the mold frame actuator to control a height of the mold frame relative to the ground surface.
A conveyor may be included and arranged to discharge material to be molded into the mold. A conveyor actuator may be configured to adjust a position of the conveyor relative to the machine frame. A conveyor sensor may be configured to provide a signal corresponding to the position of the conveyor relative to the machine frame.
In any of the above embodiments, the paving machine may further have the controller configured to control an extension of the conveyor actuator at least in part as a function of at least one of the signal from the mold frame sensor and the signal from at least one of the machine frame support sensors.
In any of the above embodiments, the slipform paving machine may further be configured such that the external reference sensor includes a stringline sensor. The controller may be configured to control extension of the machine frame support actuators and the mold frame actuator to control the height of the mold frame relative to the ground surface at least in part in response to a signal from the stringline sensor.
In any of the above embodiments, the paving machine may be further configured such that the external reference sensor is part of a three-dimensional guidance system, and the controller may be configured to control extension of the machine frame support actuators and the mold frame actuator to control the height of the mold frame relative to the ground surface at least in part in response to the signal from the external reference sensor.
In any of the above embodiments the slipform paving machine may have the height adjustable frame supports configured as lifting columns. The machine frame support actuators may include hydraulic piston-cylinder units located within their respective lifting columns. The machine frame support sensors may be integrated in their respective hydraulic piston-cylinder units. The mold frame actuator may include a hydraulic piston-cylinder unit, and the mold frame sensor may be integrated in the hydraulic piston-cylinder unit of the mold frame actuator.
In any of the above embodiments, the controller may be configured to control smaller changes in the height of the mold frame relative to the ground surface via the machine frame support actuators, and to control larger changes in the height of the mold frame relative to the ground surface via the mold frame actuator.
In any of the above embodiments the mold may further include a first side form assembly and a second side form assembly. The first side form assembly may include a first form insert, a first form insert actuator configured to adjust the height of the first form insert relative to the mold frame, a first form insert sensor configured to provide a signal corresponding to the height of the first form insert relative to the mold frame, a first side plate, and a first side plate actuator configured to adjust a height of the first side plate. Similarly, the second side form assembly may include a second form insert, a second form insert actuator configured to adjust the height of the second form insert relative to the mold frame, a second form insert sensor configured to provide a signal corresponding to the height of the second form insert relative to the mold frame, a second side plate, and a second side plate actuator configured to adjust a height of the second side plate.
In any of the above embodiments the first side form assembly may further include a first side plate sensor configured to provide a signal corresponding to the height of the first side plate, and the second side form assembly may further include a second side plate sensor configured to provide a signal corresponding to the height of the second side plate.
In any of the above embodiments the controller may be further configured to control a change in position of at least one of the first form insert actuator and the first side plate actuator, and to control a change in position of at least one of the second form insert actuator and the second side plate actuator, in response to a change of height of the mold frame relative to the ground surface.
In any of the above embodiments the controller may be configured to provide for a mode of operation wherein for a given change in height of the mold frame relative to the ground surface, on one of the first side form assembly and the second side form assembly the respective form insert actuator position is fixed and the respective side plate actuator provides a corresponding change in position, and on the other of the first side form assembly and the second side form assembly the respective form insert actuator provides a corresponding change in position while the respective side plate actuator remains fixed.
In any of the above embodiments the controller may be configured to provide for a mode of operation wherein for a given change in height of the mold frame relative to the ground surface, on each of the first side form assembly and the second side form assembly the respective form insert actuator position is fixed and the respective side plate actuator provides a corresponding change in position.
In any of the above embodiments the controller may be configured to provide for a mode of operation wherein for a given change in height of the mold frame relative to the ground surface, on each of the first side form assembly and the second side form assembly the respective form insert actuator provides a corresponding change in position while the respective side plate actuator remains fixed.
In any of the above embodiments the controller may be configured such that for a given increase in height of the mold frame relative to the ground surface there is an equal increase in a combined downward extension of the first form insert and the first side plate relative to the mold frame, and there is an equal increase in a combined downward extension of the second form insert and the second side plate relative to the mold frame.
In any of the above embodiments each of the first form insert actuator and the second form insert actuator may include a hydraulic piston-cylinder unit, and each of the first form insert sensor and the second form insert sensor may be integrated in the hydraulic piston-cylinder unit of its respective actuator.
In any of the above embodiments the left first plate actuator may be configured to adjust a height of the first side plate relative to the first form insert, and the second side plate actuator may be configured to adjust a height of the second side plate relative to the second form insert.
In another embodiment of the invention a method is provided for operating a slipform paving machine. The paving machine may include a machine frame, a plurality of ground engaging units supporting the paving machine from a ground surface, and a plurality of height adjustable machine frame supports supporting the machine frame from the plurality of ground engaging units. Each of the machine frame supports may include a machine frame support actuator configured to adjust a height of the machine frame relative to a respective one of the ground engaging units. Each of the machine frame supports may include a machine frame support sensor configured to provide a signal corresponding to the height of the machine frame relative to the respective one of the ground engaging units. The machine may further include an offset mold including a mold frame, a mold frame actuator configured to adjust a height of a mold frame relative to the machine frame, and a mold frame sensor configured to provide a signal corresponding to the height of the mold frame relative to the machine frame. The machine may further include an external reference sensor configured to provide a signal representative of a position of the slipform paving machine relative to an external reference system.
The machine may further include a controller. The method may comprise the steps of:
The slipform paving machine may further include a conveyor arranged to discharge material to be molded into the mold, a conveyor actuator configured to adjust a position of the conveyor relative to the machine frame, and a conveyor sensor may be configured to provide a signal corresponding to the position of the conveyor relative to the machine frame, and the method may further include controlling with the controller, extension of conveyor actuator in response to changes in height of the mold frame relative to the ground surface, to maintain an upper end of the conveyor above an inlet of the mold.
In any of the above embodiments the mold may further include a first side form assembly and a second side form assembly. The first side form assembly may include a first form insert, a first form insert actuator configured to adjust the height of the first form insert relative to the mold frame, a first form insert sensor configured to provide a signal corresponding to the height of the first form insert relative to the mold frame, a first side plate, and a first side plate actuator configured to adjust a height of the first side plate. Similarly, the second side form assembly may include a second form insert, a second form insert actuator configured to adjust the height of the second form insert relative to the mold frame, a second form insert sensor configured to provide a signal corresponding to the height of the second form insert relative to the mold frame, a second side plate, and a second side plate actuator configured to adjust a height of the second side plate. The method may further include controlling with the controller, one or more of the actuators of each of the first and second side form assemblies so that extension of the side form assemblies corresponds to changes in height of the mold frame.
Numerous objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon reading of the following disclosure when taken in conjunction with the accompanying drawings.
Each of the lifting columns 16 may be referred to as a height adjustable machine frame support 16 for supporting the machine frame 12 from one of the ground engaging units 18.
An offset mold 22 is supported from the machine 10. Mold 22 is of the type commonly referred to as a “large” offset mold. Such large offset molds may weigh on the order of 8 to 12 metric tons. This is contrasted to more conventional offset molds which typically have a weight on the order of 1-2 metric tons.
The direction of travel of the paving machine 10 in
A conveyor 26 is also mounted on the machine frame 12 and is arranged to discharge a material to be molded, such as concrete, from its upper end 28 into the mold 22. As will be understood by those skilled in the art, the conveyor 26 may be a belt type conveyor or alternatively it may be an auger type conveyor. A lower end 30 of the conveyor 26 will receive the material to be molded from a supply truck or the like and will convey that material upward to its upper end 28 and thus into the mold 22.
As seen in
The sensor 32S includes a position sensor electronics housing 44 and a position sensor coil element 46.
The piston portion 38 of actuator 32 includes a piston 48 and a rod 50. The piston 48 and rod 50 have a bore 52 defined therein, within which is received the piston sensor coil element 46.
The actuator 32 is constructed such that a signal is provided at connector 53 representative of the position of the piston 48 relative to the position sensor coil element 46.
Such smart cylinders may operate on several different physical principles. Examples of such smart cylinders include but are not limited to magnetostrictive sensing, magnetoresistive sensing, resistitve (potentiometric) sensing, Hall effect sensing, sensing using linear variable differential transformers, and sensing using linear variable inductance transducers.
The sensors 32S associated with the machine frame support actuators 32 may be referred to as machine frame support sensors 32S configured to provide a signal corresponding to the height of the machine frame 12 relative to the respective one of the ground engaging units 18. It will be appreciated that the sensor 32S does not need to directly measure the height of the machine frame relative to the ground engaging units, but instead the change in extension of the actuator 32 is an indirect indication of the height of the machine frame relative to the ground engaging units, because the same change occurs in the height of the machine frame relative to the ground engaging units as is measured in the extension of the actuator 32. Given the known dimensions and geometry of the other components of the paving machine 10 the desired height may be determined from the sensor signal.
As schematically illustrated in
It will be appreciated that the mold frame sensor 56S does not need to directly measure the height of the mold frame relative to the machine frame, but instead the change in extension of the actuator 56 is an indirect indication of the height of the mold frame relative to the machine frame, because the same change occurs in the height of the mold frame relative to the machine frame as is measured in the extension of the actuator 56. Given the known dimensions and geometry of the other components of the paving machine 10 the desired height may be determined from the sensor signal.
As schematically illustrated in
The conveyor actuator 58 may have a conveyor sensor 58S integrated therein as schematically represented in
It will be appreciated that the conveyor sensor 58S does not need to directly measure the position of the conveyor 26 relative to the machine frame 12, but instead the change in extension of the actuator 58 is an indirect indication of the position of the conveyor 26 relative to the machine frame 12, because the same change occurs in the height of the position of the conveyor 26 relative to the machine frame 12 at pivot point 59 as is measured in the extension of the actuator 58. Given the known dimensions and geometry of the other components of the paving machine 10 the desired position may be determined from the sensor signal.
The paving machine 10 may further include an external reference sensor 60 configured to provide a signal representative of a position of the slipform paving machine 10 relative to an external reference system 62. For example, the external reference system 62 may be comprised of a stringline 64 constructed on the ground surface 20 adjacent the location where it is desired to form the slipformed structure such as a barrier wall 90.
The external reference sensor 60 may take the form of a conventional wand type sensor arm 68 which engages and follows the stringline 64 as the slipform paving apparatus 10 moves along the ground parallel to the stringline 64. As will be understood by those skilled in the art, such stringline type external reference systems 62 may provide a reference suitable to guide the direction of the slipform paving machine 10 and also to control an elevation of the slipform paving machine 10 and thus of the attached offset mold 22.
The details of construction of the offset mold 22, in particular its internal components, are further schematically illustrated in the series of views designated as 2A-2F and in
As is seen in both
The first side form assembly 70 includes a first form insert 74 and a first side plate 76. The second side form assembly 72 includes a second form insert 78 and a second side plate 80.
The first side form assembly 70 further includes a first form insert actuator 82 configured to adjust the height of the first form insert 74 relative to the mold frame 54. The first form insert actuator 82 has integrally included therein a first form insert sensor 82S schematically illustrated in
The first side form assembly 70 further includes a first side plate actuator 84 configured to adjust a height of the first side plate 76.
As seen in the embodiment of
However, in the alternative embodiment of
The first side plate actuator 84 has integrally formed therein a first side plate sensor 84S which is schematically illustrated in
Similarly, the second side form assembly 72 further includes a second form insert actuator 86 configured to adjust the height of the second form insert 78 relative to the mold frame 54. The second form insert actuator 86 has integrally formed therein a second form insert sensor 86S schematically illustrated in
The second side form assembly 72 further includes a second side plate actuator 88 configured to adjust a height of the second side plate 80. In the embodiment of
The second side plate actuator 88 has integrally formed there in a second side plate sensor 88S schematically illustrated in
Although in
In addition to the alternative embodiment of
In a further embodiment, the first side plate actuator 84 and the second side plate actuator 88 may not include sensors, or the first side plate actuator 84 and the second side plate actuator 88 may be operated in a “floating mode”, such that instead of controlling the specific extension of the first side plate actuator 84 and the second side plate actuator 88, those actuators may be urged downwardly so that the bottom edges of first side plate 76 and the second side plate 80 slide along the ground 20.
The offset mold 22 is particularly designed for the construction of concrete barrier walls to divide lanes of a highway which are flowing in opposite directions. The general shape of the barrier wall is shown in
It is noted that the first side profile 94 includes a first step 98 and the second side profile 96 includes a step 100. As will be understood by those skilled in the art, for a typical barrier wall the height 92 may need to vary along the path of the highway, and the first and second side profiles 94 and 96 may vary in that the relative heights of their steps 98 and 100 relative to the ground surface 20 may also vary relative to each other.
In the example of
Then in
In addition to variations in the barrier profiles as shown in
The offset mold 22 disclosed herein is capable of automatically performing all these changes in the height and in the first and second side profiles of the molded barrier wall 90 through the use of a controller 110 which is schematically illustrated in
The controller 110 receives input signals from the machine frame support sensors 32S, the mold frame sensor 56S, the conveyor sensor 58S, the first form insert sensor 82S, the first side plate sensor 84S, the second form insert sensor 86S, the second side plate sensor 88S and the external reference sensor 60 all as schematically illustrated in
The controller 110 may also receive other signals indicative of various functions of the paving machine 10. The signals transmitted from the various sensors to the controller 110 are schematically indicated in
Similarly, the controller 110 will generate command signals for controlling the operation of the various actuators, which command signals are indicated schematically in
Furthermore, the controller 110 may control the direction of travel of the slipform paving machine 10 by steering of the ground engaging units 18 via a conventional steering system (not shown). Communication of such steering signals from the controller 110 to the various steered ground engaging units is preformed in a conventional manner.
Controller 110 includes or may be associated with a processor 112, a computer readable medium 114, a data base 116 and an input/output module or control panel 118 having a display 120. An input/output device 122, such as a keyboard or other user interface, is provided so that the human operator may input instructions to the controller. It is understood that the controller 110 described herein may be a single controller having all of the described functionality, or it may include multiple controllers wherein the described functionality is distributed among the multiple controllers.
Various operations, steps or algorithms as described in connection with the controller 110 can be embodied directly in hardware, in a computer program product 124 such as a software module executed by the processor 112, or in a combination of the two. The computer program product 124 can reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, or any other form of computer-readable medium 114 known in the art. An exemplary computer-readable medium 114 can be coupled to the processor 112 such that the processor can read information from, and write information to, the memory/storage medium. In the alternative, the medium can be integral to the processor. The processor and the medium can reside in an application specific integrated circuit (ASIC). The ASIC can reside in a user terminal. In the alternative, the processor and the medium can reside as discrete components in a user terminal.
The term “processor” as used herein may refer to at least general-purpose or specific-purpose processing devices and/or logic as may be understood by one of skill in the art, including but not limited to a microprocessor, a microcontroller, a state machine, and the like. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
With regard to controlling the operations of the offset mold 22, the control operations may generally be broken down into two categories. First, height of the mold 22 relative to the ground surface 20 and thus the height 92 of the resulting concrete barrier wall 90 is controlled by controlling the height of the machine frame 12 relative to the ground surface 20 via the actuators 32 within the lifting columns 16, and controlling the height of the mold 22 relative to the machine frame 12 via the mold frame actuator 56. The project plan will have determined that the barrier wall 90 should be located at a certain location on the earth's surface and that its height and side profiles should have varying specifications as the construction of the barrier wall proceeds along a predetermined path which is part of the project plan. Thus, the controller 110 will typically receive a signal from the external reference sensor 60, in response to which the controller 110 will control the extension of the machine frame support actuators 32 and the mold frame actuator 56 to control the height of the mold frame 54 relative to the ground surface 20 and thus control the resulting height 92 of the resulting molded barrier wall 90.
Thus, the controller 110 may be described as being configured to receive the signal from the external reference sensor 60 and to control extension of the machine frame support actuators 32 and the mold frame actuator 56 to control the height of the mold frame 54 relative to the ground surface 20.
The second aspect of the control provided by controller 110 is to control the actuation of the actuators 82, 84, 86, and 88 associated with the first and second side form assemblies 70 and 72 to accommodate changes in the height of the mold frame 54 relative to the ground surface 20, and to accommodate changes in the first and second side profiles 94 and 96 of the molded barrier wall 90. This control of the internal actuators of the mold 22 generally requires an extension of the overall height of the side form assemblies as the height of the mold 22 increases so the side form assemblies extend all the way downward to the ground surface 20. Additionally, the relative positions of the form inserts and the side plates may be modified to change the location of the steps 98 and 100 of the barrier wall relative to the ground surface.
It will be appreciated that for a given change in height of the mold frame 54 relative to the ground surface 20 there are a number of different combinations of actions of the actuators 82, 84, 86, and 88 associated with the interior components of the mold 22, which may be utilized to provide a corresponding change in the height of the first and second side form assemblies 70 and 72.
There are at least nine possible combinations of actions which may be utilized as shown in the following table and identified as modes 1-9.
Each of these modes of operation may be generally described as having the controller configured to control a change of position of at least one of the first form insert actuator 82 and the first side plate actuator 84, and to control a change in position of at least one of the second form insert actuator 86 and the second side plate actuator 88, in response to a change in height of the mold frame 54 relative to the ground surface 20.
Mode 1 from the table above may be described as having the controller 110 configured to provide for a mode of operation wherein for a given change in height of the mold frame 54 relative to the ground surface 20, on each of the first side form assembly 70 and the second side form assembly 72 the respective form insert actuator provides a corresponding change in position while the respective side plate actuator remains fixed.
Modes 2 and 3 from the table above are representative of another preferred control technique. Modes 2 and 3 may be generally described as having the controller 110 configured to provide for a mode of operation wherein for a given change in height of the mold frame 54 relative to the ground surface 20, on one of the first side form assembly 70 and the second side form assembly 72 the respective form insert actuator position is fixed and the respective side plate actuator provides a corresponding change in position, and on the other of the first side form assembly 70 and the second side form assembly 72 the respective form insert actuator provides a corresponding change of position while the respective side plate actuator remains fixed.
Another preferred control technique is that represented by mode 4, which may be described as having the controller 110 configured to provide for a mode of operation wherein for a given change in height of the mold frame 54 relative to the ground surface 20, on each of the first side form assembly 70 and the second side form assembly 72, the respective form insert actuator position is fixed and the respective side plate actuator provides a corresponding change in position.
It will be appreciated that each of the remaining modes of operations 5-9 provide more complex interactions of the movements of the various actuators wherein on at least one of the left and right side form assemblies 70 and 72 both associated actuators are varied in order to achieve the desired overall extension of the side form assembly and to provide the appropriate change in location of the associated step on the resulting formed concrete barrier wall.
In another embodiment of the invention, preferred modes of operation may be selected from the above table, dependent upon the magnitude and/or nature of the change in height and profile of the molded structure 90. Such selection may also be dependent upon the current state of extension of the lifting columns 16.
As previously noted one result to be achieved in association with any change in height of the offset mold 22 is that the first and second side form assemblies 70 and 72 must be extended or retracted in length to correspond to the change in height of the mold 22 so that the side plates 84 and 88 extend all the way down to or substantially down to the ground surface 20. This may be described as having the controller 110 configured such that for a given increase in the height of the mold frame 54 relative to the ground surface 20 there is an equal increase in a combined downward extension of the first form insert and first side plate relative to the mold frame, and there is an equal increase in a combined downward extension of the second form insert 78 and the second side plate 80 relative to the mold frame 54.
It will be appreciated that the offset mold 22 with its mold frame actuator 56 is constructed to provide for changes in height of the offset mold 22 relative to the ground surface which are substantially larger that any changes which could be achieved solely through the use of the actuators 32 within the lifting columns 16. On the other hand, it will be appreciated that relatively small changes in the height of the mold 22 relative to the ground surface 20 may be achieved either through use of the actuators 32 of the lifting columns 16 or through use of the mold frame actuator 56. For example, typical actuators 32 of the lifting columns 16 may be capable of moving through a leg stroke of a maximum of approximately 42 inches. The mold frame actuator 56, on the other hand, may be constructed to achieve much larger changes in elevation of the mold frame 54 relative to the machine frame 12, on the order of as much as nine feet (108 inches). It will further be appreciated that due to concerns for stability of the paving machine 10, and due to the high weight of the relatively large offset mold 22 it may be desired not to extend the actuators 32 of the lifting columns 16 to their furthest possible extension. Thus, it may be desired to only utilize the actuators 32 within a relatively small range of perhaps 24 inches.
The controller 110 may be configured to control smaller changes in height of the mold frame 54 relative to the ground surface 20 via the machine frame support actuators 32, and to control larger changes in the height of the mold frame 54 relative to the ground surface 20 via the mold frame actuator 56.
For a given height of the offset mold 22 and its mold frame 54 relative to the ground surface 20 as shown for in example in
The controller 110 may be generally described as being configured to control extension of the conveyor actuator 58 at least in part as a function of at least one of the signal from the mold frame sensor 56S and the signal from at least one of the machine frame support sensors 32S.
In
In
In
In
In
One form of external reference system which has previously been noted is the use of a stringline 62 which has been constructed on the ground surface 20 adjacent the path of the desired slipform concrete structure 90. For such an external reference system, the external reference sensor 60 may include a stringline sensor as schematically illustrated in
In connection with the use of a stringline the paving machine 10 may use a cross slope control to control the elevation of the opposite side of the machine from the stringline.
When using the stringline type of external reference system, the stringline 62 may convey the information about the desired overall height 92 of the molded structure 90. Information for the control of the position of the steps 98 and 100 formed by the form inserts 74 and 78 may be communicated to the controller 110 in various ways. One technique is to utilize a second stringline (not shown) constructed alongside the path of the barrier wall 90 which second stringline is used to communicate information regarding the desired position of one or both of the form inserts 76 and 78.
One alternative form of external reference system is the use of a three-dimensional guidance system. As will be appreciated by those skilled in the art such a three-dimensional guidance system may include one or more GPS sensors mounted on or fixed relative to the machine frame 12 or the mold frame 54 and receiving signals from a global navigation satellite system (GNSS) via which the position of the sensors within the three-dimensional reference system may be established. With such a system the external reference sensor may be described as being part of a three-dimensional guidance system and the controller 110 may be described as being configured to control extension of the machine frame support actuators 32 and the mold frame actuator 56 to control the height of the mold frame 54 relative to the ground surface 20 at least in part in response to the signals from the external reference sensors.
Another alternative form of external reference system is the use of a total station, which is another type of three-dimensional guidance system. The total station may be placed on the ground at a known location within the external reference system, and one or more reflector prisms may be mounted on the slipform paving machine. The total station measures the distance and direction to the reflectors and thus determines the position and orientation of the slipform paving machine within the external reference system. The total station may transmit a signal to the controller of the slipform paving machine, the signal being representative of the position of the slipform paving machine relative to the external reference system. The reflector prisms, in association with the total station, may be considered to be external reference sensors configured to provide a signal representative of a position of the slipform paving machine relative to the external reference system.
With any of the external reference systems described herein, the external reference sensor or sensors may be mounted on the mold frame 54, or on the machine frame 12, or elsewhere on the slipform paving machine 10. What is important is that the position of the mold frame 54 relative to the positions of the external reference sensor or sensors is known or can be determined from the geometry of the slipform paving machine 10 and the known positions of the various actuators. Regardless of the location of the external reference sensor or sensors, the external reference sensor or sensors may be described as being configured to provide a signal representative of a position of the slipform paving machine relative to the external reference system.
In combination with the input signals from either the stringline or the three-dimensional guidance system, or the total station, the controller 110 may utilize pre-programed instructions (for example via the software 124) to determine the desired overall height of the structure 90 and the desired side profiles 94 and 96 of the slipform structure 90 at various locations along the path of the paving machine 10.
When constructing a molded barrier wall 90 with the slipform paving machine 10 described above, the controller 110 will perform steps of receiving in the controller 110 a signal from the external reference sensor 60 and then controlling the extension of the machine frame support actuators 32 and the mold frame actuator 56 to control the height of the mold frame 54 relative to the ground surface 20.
In further response to changes in the height of the mold frame 54 relative to the ground surface 20, the controller 110 may control extension of the conveyor actuator 58 to reorient the conveyor 26 to keep its upper end 28 appropriately situated above the material inlet in the upper end of the mold 22.
Also, concurrently with changing the height of the mold frame 54 relative to the ground surface 20, the controller 110 may control the various actuators 82, 84, 86, and 88 associated with the first and second side form assemblies 70 and 72 so that the extension of the side form assemblies 70 and 72 corresponds to changes to height of the mold frame 54 so that the side form assemblies still extend down substantially to the ground surface 20.
Furthermore, the controller 110 may control the various actuators 82, 84, 86, and 88 to situate the form inserts 74 and 78 at appropriate elevations relative to the ground 20 to form the steps 98 and 100 of the slipformed concrete structure 90 at the appropriate elevations as desired by the construction plan.
Thus, it is seen that the apparatus and methods of the present invention readily achieve the ends and advantages mentioned as well as those inherent therein. While certain preferred embodiments of the present invention have been illustrated and described for purposes of the present disclosure, numerous changes in the arrangement and construction of parts and steps may be made by those skilled in the art which changes are encompassed within the scope and spirit of the present invention as defined by the appended claims.
