Patent Publication Number: US-2023146262-A1

Title: Piston lock system for agricultural equipment

Description:
BACKGROUND OF THE INVENTION 
     Agricultural equipment, such as combine harvesters that are used to gather agricultural crops, typically have a header that is configured to remove the crop material from the ground, and a feeder that conveys the crop material to the main body of the vehicle for processing and temporary storage. The feeder typically is encased in a feeder housing, which may be connected to the vehicle chassis by hydraulic cylinders, in order to allow the header to move relative to the chassis. At times, it may be necessary to extend the hydraulic cylinders to raise the header out of contact with the ground. For example, it may be desirable to raise the header during road transport and other non-harvesting movements, and to allow service of the header and related parts. Under these circumstances (and especially during service), it may be desirable to lock the feeder in the raised position to inhibit accidental lowering of the feeder and header. 
     One way to lock the feeder in the raised position is to place a blocking member around the piston member of a hydraulic actuator that connects the feeder (and thus the header) to the vehicle chassis. For example, a lock in the form of a rigid rod or shaft having an open slot along the side can be slipped over the piston when it is extended from the cylinder, with the ends of the lock terminating adjacent to the two exposed ends of the piston. One end of the lock rests against the end face of the cylinder, and the other end of the lock rests against the end fitting of the cylinder (or another adjacent structure, such as a clevis into which the end fitting is installed), thereby preventing the piston from retracting into the cylinder. 
     It is also known to connect multiple cylinder locks to each other, such that they can be simultaneously moved into place over respective pistons. U.S. Pat. No. 4,529,215, which is incorporated herein by reference, discloses a cylinder lock member in the form of two straps that are pivotally connected to the free end of the piston. Multiple lock members may be connected to each other by a pivot shaft that extends between the cylinder assemblies. In use, the lock members rotate out of the plane defined by the cylinder assemblies. This requires a large clear space adjacent to the cylinder assemblies, and limits or prohibits the applicability of this mechanism when there is no free space to allow the lock members to rotate. Thus, such a mechanism is only feasible when there is sufficient room for the system. 
     While various cylinder lock mechanisms are known, it has been found that they can be cumbersome and time-consuming to operate, and may not have sufficient strength to hold large modern headers and feeders. 
     This description of the background is provided to assist with an understanding of the following explanations of exemplary embodiments, and is not an admission that any or all of this background information is necessarily prior art. 
     SUMMARY OF THE INVENTION 
     In one exemplary aspect, there is provided a piston lock system comprising: a first cylinder extending from a first fixed cylinder end to a first free cylinder end; a first rod receiver fixed to the first cylinder; a first piston extending through the first free cylinder end from a first sliding piston end contained in the first cylinder to a first free piston end located outside the first cylinder; a first rod extending, parallel to the first piston, from a first fixed rod end secured to move with the first free piston end to a first sliding rod end located within the first rod receiver, wherein the first piston and first rod are movable relative to the first cylinder and first rod receiver between a first retracted position and a first extended position, with the first free piston end and first fixed rod end being farther from the first free cylinder end in the first extended position than in the first retracted position; and a first lock pin mounted to the first rod receiver and movable between a first unlocked position in which the first lock pin does not intersect a path of the first rod, and a first locked position in which the first lock pin intersects the path of the first rod and prevents the first rod and first piston from moving from the first extended position to the first retracted position. 
     In another exemplary aspect, there is provided an agricultural combine comprising: a chassis configured for movement on a surface; a feeder housing pivotally connected to the chassis; and a piston lock system as described in the foregoing aspect and examples. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of inventions will now be described, strictly by way of example, with reference to the accompanying drawings, in which: 
         FIG.  1    schematically illustrates a side view of an example of an agricultural combine having a piston lock system such as described herein. 
         FIG.  2    is an isometric view of an exemplary embodiment of a piston lock system. 
         FIGS.  3 A and  3 B  are top plan views of the piston lock system of  FIG.  2   , shown in the unlocked and locked positions, respectively. 
         FIGS.  4 A and  4 B  are isometric views of a portion of the piston lock system of  FIG.  2   , shown in the unlocked and locked positions, respectively. 
         FIGS.  5 A and  5 B  are top plan views of another piston lock system, shown in the unlocked and retracted position, and the extended and locked position, respectively. 
         FIGS.  6 A and  6 B  are top plan views of another piston lock system, shown in the unlocked and retracted position, and the extended and locked position, respectively. 
         FIGS.  7 A and  7 B  are top plan views of another piston lock system, shown in the unlocked and retracted position, and the extended and locked position, respectively. 
         FIGS.  8 A and  8 B  are side views of the piston lock system of  FIGS.  7 A and  7 B , shown in the unlocked and retracted position, and the extended and locked position, respectively. 
         FIGS.  9 A and  9 B  are top plan views of another piston lock system, shown in the unlocked and retracted position, and the extended and locked position, respectively. 
     
    
    
     In the figures, like reference numerals refer to the same or similar elements. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the present invention provide piston lock systems which may be used in agricultural equipment (e.g., combines, windrowers, etc.), or in other environments. However, the invention is not limited to any particular application except as may be specifically recited in the claims. 
     Referring to  FIG.  1   , an example of an agricultural vehicle  100 , which in this case is an agricultural combine, is schematically illustrated. The vehicle  100  includes a chassis  102  that is supported for movement on the ground by wheels  104  (e.g., pneumatic tires or tracked wheels). A header assembly  106  is attached to the combine  100  and configured to receive crop material and convey such material to a threshing and separating system  108  located in or on the chassis  102 . The threshing and separating system  108  separates grain from the remaining crop material (also known as “material other than grain,” “MoG,” or “residue”). The separated grain is stored in a hopper  110 , and the MoG is evacuated to the trailing path of the vehicle  100  by a spreader  112 . 
     The header assembly  106  comprises a feeder housing  114  and a header  116 . The feeder housing  114  is pivotally connected to the chassis  102  at a horizontal pivot  118 . One or more actuators  120  are connected between the chassis  102  and the feeder housing  114 . Each actuator comprises a hydraulic cylinder and piston assembly with a piston lock system, such as described in more detail below. 
     The features described in relation to  FIG.  1    are generally conventional, except for the actuators, and particularly the piston lock system, and no further explanations of their structures or operations are necessary. 
     Referring now to  FIG.  2   , a first example of a piston lock system is shown and described in detail. In this case, the piston lock system is shown installed on a first actuator  120   a  and a second actuator  120   b , but it will be appreciated that features of the piston lock system may be implemented on a single actuator. 
     Each actuator  120  comprises a cylinder  200  extending from a fixed cylinder end  202  to a free cylinder end  204 , and a piston  206  extending through the free cylinder end  204  from a sliding piston end  208  to a free piston end  210 . The sliding piston end  208  is contained in the cylinder  200 , and the free piston end  210  is located outside the cylinder  200 . The piston  206  is slidable relative to the cylinder  200  in a manner that is conventional in the art of hydraulic actuators. For example, a hydraulic system may include a one or more hydraulic ports  212  that are fluidly connected to the interior of the cylinder, and configured to convey pressurized hydraulic fluid to extend or retract the piston  206  relative to the cylinder  200 . Such hydraulic systems are conventional, and need not be described in further detail herein. 
     At least one rod receiver  214  is fixed to each cylinder  200 . In the shown example, each cylinder  200  has two rod receivers  214  located on opposite sides of the cylinder  200 . Each rod receiver  214  comprises a housing-like structure having a longitudinal passage  216   a  that is oriented in parallel with the sliding direction of the piston  206 , and a lateral passage  216   b  oriented at an angle to the sliding direction of the piston  206 . Examples of the longitudinal passage  216   a  and lateral passage  216   b  are shown in  FIG.  5 A . The lateral passage  216   b  includes a wall facing towards the free cylinder end  204 , which serves as a surface that bears loads to lock the piston  206  in position. to this end, the lateral passage  216   b  preferably extends perpendicular to the sliding direction of the piston  206 , but this is not strictly required. 
     At least one rod  218  is attached to each piston  206 . In the shown example, there are two rods  218  attached to opposite sides of each piston  206 . Each rod  218  extends, parallel to the piston  206 , from a fixed rod end that is secured to the free piston end  210 , to a free rod end that extends into a respective rod receiver  214 . The fixed rod end, and thus the entire rod  218 , is configured to move in unison with the free piston end  210 . For example, the rod  218  may be attached by a bolt, adhesives or welding to a boss extending from a side of the free piston end  210 . 
     As shown, for example in the embodiment shown in  FIGS.  5 A and  5 B , the pistons  206  and rods  218  are telescopically movable relative to the respective cylinders  200  and rod receivers  214  between a retracted position ( FIG.  5 A ) and an extended position ( FIG.  5 B ). The free piston ends  210  and fixed rod ends are farther from the free cylinder ends  204  in the extended position than in the retracted position. As noted above, suitable hydraulic controls may be used to extend and retract the pistons  206  relative to the cylinders  200 . 
     At least one lock pin  220  is mounted to each cylinder  200 . For example, a lock pin  220  may be slidingly connected to each rod receiver  214 . The lock pins  220  are movable between an unlocked position ( FIG.  3 A ) in which the lock pins  220  do not intersect a path of the respective rod  218 , and a locked position ( FIG.  3 B ) in which the lock pin  220  intersects the path of the respective rod  218 . In the locked position, each lock pin  220  is captured between the free end of rod  218  and a wall of the lateral passage  216 , and thus prevents the rod  218  and piston  206  from moving from the extended position to the retracted position. 
     While it is envisioned that the lock pins  220  may be separately moved between their respective locked and unlocked positions, it is more preferred to provide a mechanism to simultaneously operate all of the lock pins  220 . This provides greater assurance that all of the lock pins  220  are properly positioned to prevent the pistons  206  from inadvertently retracting from the extended position towards the retracted position. In the example of  FIGS.  2 - 4 B . The lock pins  220  associated with each cylinder  200  are connected to each other by a plate  222 , to thereby cause them to move in unison. In addition, the lock pins  220  from one actuator  120   a  are connected to the lock pins  220  of the other actuator  120   b  by a control link  224  that is configured to simultaneously move the lock pins  220  of the first actuator  120   a  with the lock pins  220  of the second actuator  120   b  between their respective locked and unlocked positions 
     In this example, the control link  224  comprises a central transfer link  226 , a first connecting link  228  joining the lock pins  220  of the first actuator  120   a  to the transfer link  226 , and a second connecting link  230  joining the lock pins  220  of the second actuator  120   b  to the transfer link. The transfer link is pivotally mounted at a transfer link pivot  232 . The transfer link pivot  232  is fixed to move in unison with the actuators  120   a ,  120   b , and thus maintains an appropriate position to anchor the transfer link  226  throughout the range of motion of the entire assembly. For example, the transfer link pivot  232  may be secured to one or both cylinders  200  by one or more braces, such as the illustrated cross braces  234 . The cross braces  234  may be secured to the cylinders  200  by a direct connection or by connection to the rod receivers  214 . 
     When installed on a vehicle  100 , the cylinders  200  are configured to be coplanar or parallel throughout their respective ranges of motion. When coplanar, the fixed cylinder ends  202  and free piston ends  210  all lie in a common plane. When parallel, the fixed cylinder ends  202  and free piston ends  210  all lie in a common plane, and the cylinders  200  and pistons  206  are parallel within the common plane. In either case, some variation may occur during regular use due to differential loading and slight differences in hydraulic system operations. In either case, the cylinders  200  define a plane between them, and the transfer link pivot  232  may be oriented with a rotation axis that extends orthogonal to the plane defined between the two cylinders  200 . The transfer link pivot  232  may comprise a pin or the like that extends orthogonal to this plane. As will be clear from the following explanation of the operation of the control link  224 , this orthogonal orientation allows the control link  224  to remain generally within the plane throughout the range of motion, leading to a more compact system. 
     The first connecting link  228  and second connecting link  230  are attached by pivots to opposite ends of the transfer link  226 , with the transfer link pivot  232  being approximately midway between the connections to the two connecting links  228 ,  230 . Thus, movement of one connecting link  228  causes a corresponding opposite movement of the other connecting link  230 . Each connecting link  228 ,  230  is also connected, at its opposite end, to one of the lock pins  220  or (if used) the lock pin plate  222 . Thus, movement of a lock pin  220  on one actuator  120   a  causes a simultaneous and opposite movement of a connected lock pin  220  on the other actuator  120   b.    
     The control link  224  may be operated using any suitable mechanism. For example, in  FIGS.  2 - 4 B , a handle  236  may be connected to the lock pins  220  or lock pin plate  222  of one actuator  120   a . The handle  236  is positioned and configured for manual operation by a technician. For example, the handle  236  may comprise an elongated bar that is located on a side of the cylinder  200  opposite the control link  224 , to allow operation without having to enter the space between the two actuators  120   a ,  120   b . The handle  236  also may include a service lock  238  ( FIG.  4 B ) to prevent inadvertent operation to move the lock pins  220  from the locked position to the unlocked position. The service lock  238  may comprise, for example, a pin that is insertable into a hole in the end of the lock pin  220 , to prevent withdrawal from the locked position. The control link  224  also may be operated by a remote system, such as described below. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     Referring now to  FIGS.  3 A- 4 B , the operation of the lock pins  220  is shown in more detail.  FIGS.  3 A and  4 A  show the lock pins  220  in the unlocked position, and  FIGS.  3 B and  4 B  show the lock pins  220  in the locked position. In this case, the control link  224  is located entirely in a space between the two cylinders  200 . During operation, the lock pins  220  of each cylinder move in opposite directions. Specifically, the lock pins  220  for the first actuator  120   a  move away from the second actuator  120   b  when moving from the unlocked position to the locked position, and the lock pins  220  for the second actuator  120   b  move away from the first actuator  120   b  when moving from the unlocked position to the locked position. The reverse operation moves the lock pins  220  to their unlocked positions. 
       FIGS.  5 A and  5 B  show an alternative piston lock system. In this case, the mechanisms are generally the same as in the embodiment of  FIGS.  2 - 4 B , so this description addresses the differences between the embodiments. 
     First, the handle  236  is replaced by a powered actuator  500 . The actuator  500  may be any suitable powered motion device, such as a pneumatic, hydraulic or electric telescoping element (e.g., a piston/cylinder assembly). The actuator  500  can be operated remotely, either by an automated control system or by a user&#39;s direct input. 
     Second, the control link  224  is provided in the form of a pushrod  502  that extends to connect the lock pins  220  of the first actuator  120   a  with the lock pins  220  of the second actuator  120   b . The lock pins  220  are slidably mounted to the rod receivers  214 , and the pushrod  502  is configured to move along an axis A extending between the cylinders  200  of the first and second actuators  120   a ,  120   b . This axis A may extend perpendicular to the cylinders  200 , but this is not strictly required. The pushrod  502  may be rigidly connected to the lock pins  220 , or connected by pivots or other flexible connectors to allow some relative displacement between the two actuators  120   a ,  120   b  without interfering with proper operation of the lock pins  220 . The pushrod  502  also may be connected directly to the lock pins  220 , or to a structure that holds the lock pins  220 , such as the plate  222  described above. 
     In use, the actuator  500  drives one end of the pushrod  502  or one set of lock pins  220 , and such motion is transferred to the other lock pins by the pushrod  502 . In this example, the lock pins  220  all move in the same direction between their respective locked and unlocked positions. For example, first lock pin or pins  220  of the first actuator  120   a  move towards the second actuator  120   b  when moving from the unlocked position to the locked position, and the lock pin or pins  220  of the second actuator  120   b  move away from the first actuator  120   a  when moving from the unlocked position to the locked position. This arrangement has the benefit of potentially being simpler and less prone to service requirements as the embodiment of  FIGS.  2 - 4 B , but also may be less compact due to parts of the control link  224  being outside the space between the actuators  120   a ,  120   b . It will also be understood that this embodiment (and all other embodiments described herein) may have a manually-operated handle  236  and/or a powered actuator  500 . 
       FIGS.  6 A and  6 B  show another alternative embodiment. In this case, the sliding lock pins  220  of the previous embodiment are replaced by rotating lock pins  220 . The rotating lock pins  220  are connected by an arm  600  and a pivot  602  to the cylinder  200  and/or rod receiver  214 . In this case, the control link  224  is a pushrod  502  that is operated by a handle  236 . If necessary, the pushrod  502  may be connected to the arm  600  by another pivot  604 , to allow the pushrod  502  to remain oriented towards a lock pin  220  on an adjacent actuator (not shown in  FIGS.  6 A and  6 B ). In use, the pushrod  236  is moved to rotate the arm  600  and place the lock pin  220  into the lateral passage  216   b.    
     In other embodiments, different pivoting or moving connections may be provided between the lock pins  220  and the rod receiver  214 , and other control links may be used. 
       FIGS.  7 A- 8 B  show another embodiment. In this case, the control link  224  comprises an axle  700  extending from the lock pin  220  of the first actuator  120   a  to the lock pin of a second actuator (not shown). The axle  700  is pivotally mounted to the cylinders  200  (either directly or via the rod receiver  214  or other structure), and configured to rotate about an axis A extending between the actuators  120   a ,  120   b . The lock pins  220  are rigidly connected to the axle  700  by one or more offset arms  702 , and thus move with the axle  700  through an arcuate path as the axle  700  rotates. A handle  236  or other control is provided to rotate the axle  700 . 
     As best shown in  FIGS.  8 A and  8 B , rotating the axle  700 , such as by operating a handle  236  or other control, moves the lock pins  220  between an unlocked position ( FIGS.  7 A and  8 A ) and a locked position ( FIGS.  7 B and  8 B ). As shown in  FIG.  7 B , in the locked position, the lock pin  220  is positioned between the rod  218  and an inner face  704  of the rod receiver  214 , and preferably in contact with both the inner face  704  and the rod  218  to provide a direct load-bearing path from the rod to the rod receiver  214 . If necessary, the lock pin  220  may be connected to the axle  700  or offset arms  702  by a lost-motion mechanism (e.g., a pin that fits into a slot or oversized hole), to allow the lock pin  220  to move slightly to make contact with the surface  704 . 
     The foregoing arrangement of direct contact and a direct load-bearing path is also preferred for the other embodiments described herein to simplify the structural requirements to support the piston  206  in the extended position. In each case, some lost motion (i.e., limited free movement between the parts) or flex may be designed into the lock pins  220  and related parts to ensure proper contact under various operating conditions and to account for potential tolerance stacking issues. 
       FIGS.  9 A and  9 B  show a further embodiment, in which a cam  900  is used to move the lock pin  220  between the locked and unlocked positions. The cam  900  is rotatably mounted to the cylinder  200  or rod receiver  214 , and includes a helical cam track  902 . A cam follower  904 , such as a pin, is attached to the lock pin  220  (or to a plate  222  or other comparable structure), and positioned within the cam track. A handle  236  is provided to rotate the cam  900 . Rotating the cam  900  causes the cam track  902  to drive the cam follower  904 , thus moving the lock pin  220  between the locked and unlocked positions. 
     In the shown embodiment, a pushrod  502  is attached to the lock pin  220  to transfer motion to another lock pin on an adjacent actuator, but this is not strictly required. In other examples, there may not be another actuator, or the other actuator or actuators may have separate lock pin controls. In still another example, each actuator may have its own cam  900  or cams, and the cams of the actuators may be joined by an axle such as the axle  700  of the embodiment of  FIGS.  7 A- 8 B . In this case, rotating the axle  700  would rotate both cams  900  in unison, and each cam  900  would drive its respective lock pin  220  between the locked and unlocked positions. Other alternatives and variations will be apparent to persons of ordinary skill in the art in view of the present disclosure. 
     It will be appreciated that embodiments such as described herein can be used in various locations on agricultural vehicles and equipment, particularly those having multiple actuators. For example, the actuators  120   a ,  120   b  may be mounted with the fixed cylinder ends  202  connected to a vehicle chassis  102 , and the free rod ends  210  connected to a feeder housing  114 , or vice-versa. Such connections can be made in the manner of a conventional actuator, and thus embodiments may be provided as a retrofit assembly for an existing vehicle  100 . 
     It is expected that embodiments will provide easier and more efficient options to lock pistons of actuators in the extended positions, and thus can improve serviceability and safety of such devices. Furthermore, embodiments having the capability to simultaneously operate lock pins on multiple actuators can have a significant benefit in cases in which locking a single actuator is not sufficient to adequately secure a load. For example, modern agricultural combine headers having two actuators can weigh too much to be reliably held by a single one of its actuators, in which case the ability to simultaneously lock both actuators is particularly desirable. 
     The present disclosure describes a number of inventive features and/or combinations of features that may be used alone or in combination with each other or in combination with other technologies. The embodiments described herein are all exemplary, and are not intended to limit the scope of the claims. It will be appreciated that various aspects of the embodiments described herein may be provided as component parts or as subassemblies. It will also be appreciated that the inventions described herein can be modified and adapted in various ways, and all such modifications and adaptations are intended to be included in the scope of this disclosure and the appended claims.