Abstract:
A cable actuated pin latching mechanism adapted for releasably connecting a header to a feeder of a combine, which automatically maintains predetermined tension conditions on the cable during normal latching and unlatching operation, and when an actuator of the mechanism is held in an unlatch position with the latch pin stuck or restrained, applies and maintains a tension force for releasing the pin, for instance, to enable a user to move to the operator cab to operate lift, tilt and/or other controls, as required for freeing the pin.

Description:
TECHNICAL FIELD 
     This invention relates generally to a cable actuated pin latching mechanism for releasably connecting components together, which mechanism is particularly adapted for locking a header to a feeder or other support structure of an agricultural combine, and which automatically maintains predetermined tension conditions on the cable during normal operation, and applies a tension force for releasing the latching pin when stuck. 
     BACKGROUND ART 
     Work machines, such as agricultural combines, often include removable components or attachments, such as a header for harvesting crops from a field. For some applications, such components, and headers in particular, are required to be installed and removed at isolated locations such as the boundary regions of large agricultural fields, often by a person working alone. In some instances, installation and removal must be done several times a day, for instance, wherein a farming operation comprises several parcels of land to be harvested, and the combine must be driven over roads or lanes from parcel to parcel, with the header removed. Additionally, the header must sometimes be installed and removed on uneven surfaces, which can place loads on the connecting apparatus to make it difficult to connect and disconnect. 
     Some known mechanisms for locking or latching a header to a feeder of a combine utilize an actuating cable connected between a handle and the latch pin of the mechanism, to enable remote actuation. An advantage of this is that it enables operating latching mechanisms located at the bottom of the feeder from a more convenient location, and operating latches on opposite sides of the feeder from a single location on one side. The known mechanisms typically operate by pushing on the cable to urge a latch pin into a receiver, and pulling on the cable to remove the pin from the receiver. Problems found with this arrangement, however, include that repeated pushing on the cable, particularly when required to force the latch pin into the receiver, weakens the cable over time. Another problem is that when the pin is stuck in the receiver, users sometimes apply tensile forces to the cable to free the pin which exceed the tensile strength of the cable, which can cause breakage thereof. Freeing a sticking pin can require moving the feeder and header, which is typically done using controls in the operator cab of the combine, and can require the user to climb to and from the cab one or more times to do so. 
     One solution to the cable breakage problem known to be utilized by other manufacturers, is to provide a shear pin between the actuator handle and the cable, which pin will break if subjected to a force some amount less than the tensile strength of the cable. However, a shortcoming of this solution is that if the shear pin is broken, it must be replaced to render the mechanism operable again, and the latch pin will still need to be freed. 
     Accordingly, what is sought is a cable actuated pin latching mechanism adapted for connecting a header to a feeder of an agricultural combine, which overcomes one or more of the problems and shortcomings set forth above, is simple and reliable in construction and operation, and is advantageous costwise. 
     SUMMARY OF THE INVENTION 
     What is disclosed is a cable actuated pin latching mechanism adapted for releasably connecting a header to a feeder of a combine, which overcomes one or more of the problems set forth above, by automatically maintaining predetermined tension conditions on the cable during normal latching and unlatching operation, and when an actuator of the mechanism is held in an unlatch position with the latch pin stuck, applies and maintains a tension force for releasing the pin, to enable a user to move to the operator cab to operate lift, tilt and/or other controls, as required for freeing the latch pin. 
     According to a preferred embodiment of the invention, the latching mechanism includes a latch pin supported for movement in opposite latching and unlatching directions, and an actuator supported for movement between a latching position and an unlatching position. The mechanism includes an elongate cable having one end portion connected to the latch pin and an opposite end connected to the actuator, a portion of the cable being disposed between the latch pin and the actuator being contained and movable longitudinally within a sheath. The mechanism includes a first biasing element disposed and supported for yieldably exerting a first biasing force in the latching direction against the latch pin and against the cable for applying a tensile loading condition on the cable. When the latch pin is freely movable in the latching direction, movement of the actuator toward the latching position will allow the first biasing element to move the cable to move the latch pin in the latching direction while maintaining the tensile loading condition on the cable. When the latch pin is freely movable in the unlatching direction, movement of the actuator toward the unlatching position will move the cable to move the latch pin in the unlatching direction. The mechanism further includes a second biasing element disposed and supported in cooperation with the sheath such that if the latch pin is displaced in the latching direction and restrained against movement in the unlatching direction, movement of the actuator to the unlatching position will cause the second biasing element to yieldably exert a second biasing force in the unlatching direction against the sheath, the cable and the latch pin. 
     According to a preferred aspect of the invention, the cable is maintained in tension, as the latch pin is both latched and unlatched, to avoid problems related to compression loading on the cable. As another preferred aspect of the invention, when the pin is stuck in a latched position, for instance, when retained in a pin receptacle or receiver on an element or attachment to be connected to a work machine, the actuator can be moved to and held in the unlatch position, to allow a user or operator to take steps to free the pin, and when freed, the pin will be retracted from the receiver automatically by the second biasing force. This allows the user the ability to leave the actuator and work elsewhere to free the pin. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of an agricultural combine having a cable actuated pin latching mechanism according to the invention, located on a feeder of the combine and operable for releasably locking a header to the feeder; 
         FIG. 2  is a perspective view of the feeder and header of  FIG. 1 , showing the latching mechanism of the invention; 
         FIG. 3  is an enlarged perspective view of the feeder and the header, showing aspects of the latching mechanism; 
         FIG. 4  is an enlarged perspective view of an actuator handle of the mechanism in a latching position; 
         FIG. 5  is an enlarged perspective view of the actuator handle of the mechanism in an unlatching position; 
         FIG. 5A  is another enlarged perspective view of the actuator handle of the mechanism in an unlatching position and showing a detent mechanism of the invention; 
         FIG. 6  is an enlarged view of a latch pin assembly and pin receiver of the mechanism, on the feeder and header, respectively, and showing the latch pin received in the receiver; 
         FIG. 6A  is another enlarged view of the latch pin assembly, showing internal details thereof; 
         FIG. 7  is an end view of the latch pin assembly and pin receiver of the mechanism, on the feeder and header, respectively, and showing the latch pin withdrawn from the receiver; 
         FIG. 8  is a simplified view of aspects of the latch pin assembly, showing the latch pin received in the pin receiver; 
         FIG. 9  is another simplified view of the aspects of the latch pin assembly, showing the latch pin stuck in the pin receiver with tension applied to the cable of the mechanism for freeing the pin; and 
         FIG. 10  is another simplified view of the aspects of the latch pin assembly, showing the latch pin freed from the pin receiver. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Turning now to the drawings, in  FIGS. 1 ,  2 ,  3  and  4 , aspects of a preferred embodiment of a cable actuated pin latching mechanism  20  according to the present invention are shown, like parts being identified by like numerals. Latching mechanism  20  is shown in association with a feeder  22  of a representative agricultural combine  24 , and is operable for connecting or locking a header, represented by header  26  to a front end  28  of feeder  22 . Feeder  22 , combine  24  and header  26  are all of well known, conventional construction. Here, it should be noted that agricultural combine  24  is intended to be illustrative of a wide variety of work machines and applications with which a mechanism including the features of the invention, as represented by mechanism  20 , can be used, and therefore, the present invention is not to be interpreted as being limited to the application shown and described herein. 
     Referring also to  FIG. 5 , latching mechanism  20  includes an actuator assembly comprising an actuator  30  supported by structure on a side sheet of feeder  22  or other suitable location, which structure here includes a bracket  32  supporting actuator  30  by a pivot pin  48 , so as to be manually movable between a latching position ( FIG. 2 ) and an unlatching position ( FIG. 5 ). Latching mechanism  20  includes at least one, and preferably two, latch pin assemblies, each including a latch pin  34 , and structure, here including a tubular bracket  36 , supporting the latch pin  34  for movement in a latching direction, denoted by respective arrows A, and in an unlatching direction, denoted by respective arrows B, opposite latching direction A, respectively. Latching mechanism  20  additionally preferably includes two cable assemblies, each comprising an elongate cable  38  connecting respectively, to one of the latch pin assemblies. Each cable  38  has a first end portion  40  connected in the manner described below to a respective latch pin  34 , an opposite second end portion  42  connected to actuator  30 , and an intermediate portion between end portions  40  and  42  contained and movable longitudinally within a sheath  44 . 
     End portions  42  of cables  38  are preferably connected to actuator  30  by a clevis  46 , or other suitable connector, and sheath  44  is suitably mounted and restrained, as will be explained, such that pivotal or other desired movement of actuator  30  about pin  48  from the unlatching position ( FIGS. 1 ,  2  and  4 ) as denoted by arrow C in  FIG. 4 , with pins  34  unrestrained and freely movable, will effect movement or displacement of cables  38  in a direction, denoted by arrow B 1 , for moving latch pins  34  in the unlatching direction B ( FIG. 2 ), and such that pivotal movement of actuator  30  from the latching position ( FIG. 5 ) in the direction denoted by arrow D, will cause movement or displacement of cables  38  in a direction A 1  for moving latch pins  34  in the latching direction A ( FIG. 2 ). 
     Referring in particular to  FIG. 2 , and also to  FIGS. 6 ,  6 A and  7 , mechanism  20  includes a first biasing element  50  disposed and supported in connection with each of the respective latch pin assemblies, preferably around first end portion  40  of cable  38 . The biasing element  50  is preferably a compression coil spring, one end of which is retained by a bracket  52 , and the opposite end of which is received in a cavity  54  within pin  34  and bears against a shoulder therein. End portion  40  of cable  38  has a threaded end  56  which passes through the shoulder in cavity  54 , and which is retained by nuts  58  on the opposite side of the shoulder. This enables compressing biasing element  50 . Sheath  44  includes a threaded end  60  fixedly mounted to a bracket  62  on feeder  22  by nuts  64 , which enables longitudinal movement of pin  34 , cable  38 , and biasing element  50 , relative to the sheath. As a result of this construction, the biasing element  50  associated with each of the latch pin assemblies will yieldably exert a first biasing force, denoted by arrow F 1  in  FIG. 6A , against the respective latch pin  34  for urging it in its respective latching direction A. Because the opposite end of cable  38  is held by actuator  30 , this also applies a tensile loading condition on cables  38 , such that, when latch pins  34  are freely movable in latching direction A, movement of actuator  30  in direction C ( FIG. 4 ) toward the latching position, will allow biasing elements  50  to move cables  38  longitudinally within sheaths  44 , so as to move latch pins  34  in their latching directions to a latched position ( FIGS. 6 and 6A ) while maintaining the tensile loading conditions on cables  38 . Also, when latch pins  34  are freely movable in their respective unlatching directions B, movement of actuator  30  in direction D toward the unlatching position ( FIG. 5 ) will move cables  38 , under the tensile loading condition, to move latch pins  34  in the unlatching directions, to their unlatched positions ( FIG. 7 ). Additionally, if one or both pins  34  is stuck, restrained or otherwise prevented or blocked from movement in latching direction A, cable  38  is movable longitudinally relative to the stuck pin, such that if actuator  30  is moved in the latching direction, cable  38  will be allowed to move in direction A through the stuck pin  34 , such that compression loading of the cable is avoided. Configured as shown, when actuator  30  is moved to the unlatching position, first biasing element  50  will be compressed to a greater extent compared to when actuator  30  is in the latching position, and thus will store greater energy compared to when actuator  30  is in its latching position, but in both positions, it is preferred that biasing element  50  be compressed at least somewhat, to maintain a tensile loading condition on cable  38 . 
     Referring more particularly to  FIGS. 2 ,  3 ,  6  and  7 , for the representative application shown and discussed herein, which is the connection of a header, represented by header  26 , to the front end of feeder  22 , header  26  is illustrated as including a pair of latch pin receivers  66  at predetermined positions for cooperatively receiving latch pins  34  when feeder  22  and header  26  are positioned and aligned in predetermined relation for connection. For this pin receiver configuration, pins  34  are positioned and located adjacent to opposite sides of feeder  22  such that the respective latching directions A for the two pins are opposite directions. Here, it should be understood that it is contemplated that other configurations can be used as desired. Each receiver  66  preferably essentially comprises a bracket or other suitable structure projecting from a bottom edge of header  26 , and including a hole  68  therein adapted for receiving a pin  34 . Additionally, as illustrated in  FIG. 7 , receiver  66  includes an optional pin retainer  70  configured for preventing passage of a pin  34  totally through hole  68  in the event of failure of cable  38 , and as possibly propelled by the release of stored energy of biasing element  50 . 
     Thus, to reiterate, it should be evident that under normal conditions, that is, with pin  34  freely movable, manual movement of actuator  30  to the latching position, will effect simultaneous insertion of pins  34  disposed adjacent to the opposite sides of feeder  22 , into the respective holes  68  of receivers  66  on header  26 , for connection of the header to the feeder, with cables  38  maintained in a tensile loading condition. And, in the event that the path of either of pins  34  is blocked, for instance, as a result of misalignment with hole  68 , the hole  68  is blocked, or pin  34  is stuck, when actuator  30  is moved to the latching position, cable  38  for the blocked or stuck pin can move through the pin, to avoid compression or loading of the cable  38 , and there is sufficient space within the end of pin  34  to accomplish this without the end of the cable itself being driven into an obstruction. Similarly, under normal conditions, movement of actuator  30  to the unlatching position, will effect simultaneous withdrawal of pins  34  from receivers  66 , cables  38  still being maintained in tension. However, it is anticipated that, from time to time, one or both pins  34  may be restrained against withdrawal from its receiver  66 , or otherwise stuck therein, so as not to be removable using the tensile loading condition that can normally be achieved by manual movement of actuator  30 . This can result, for instance, from positioning or orienting the header and feeder at a tilt, so as to resultingly apply a large shear loading condition against one or both pins  34 , which load cannot be overcome by the normal tensile loading condition applied manually using actuator  30 . It can also result from corrosion or seizing, or damage to a pin  34  and/or receiver  66 . As noted above, when this occurs, users have been known to apply forces in excess of the tensile strength of a cable  38  in an attempt to free the stuck pin or pins  34 , which has resulted in stretching, weakening, and even breaking of the affected cable. This of course is not desired, as it can result in machine downtime, loss of productivity, and user dissatisfaction. 
     To avoid the problems just discussed, mechanism  20  additionally utilizes a second biasing elements  72  disposed and supported such that if one or both latch pins  34  is stuck. such as by being restrained, obstructed, seized or the like, movement of actuator  30  to the unlatching position will cause an associated second biasing element  72  to yieldably exert a second biasing force, denoted by arrows F 2  in  FIGS. 6 and 6A , in the unlatching direction against the affected pin or pins  34 . As a result, force F 2  is only applied when a pin or pins  34  is stuck, and not when freely movable. 
     Referring more particularly to  FIGS. 4 and 5 , and also to  FIGS. 8 ,  9  and  10 , to achieve the above capability, second biasing elements  72  preferably comprise sheath springs disposed around second end portions  42  of cables  38 , respectively, and retained between the adjacent end of the associated sheath  44 , and a structural element of the actuator assembly. Here, a preferred structural element is a bracket  74  through which the respective cables  38  pass enroute to connection with actuator  30 . Bracket  74  is preferably of bifurcated, U-shaped, or other suitable construction, including a first leg  76  on which bracket  32  supporting actuator  30  is mounted, and which retains biasing elements  72  against movement toward actuator  30 . A second leg  78  of bracket  74  includes holes therethrough sufficiently large for passage of cables  38  therethrough, respectively, including sheaths  44  thereof. Biasing elements  72  are retained in connection with the respective sheaths  44  by retainers  80  mounted around the ends of the sheaths, which retainers  80  are sized so as not to pass through the holes in legs  78 . Biasing elements  72  are compressed between leg  76  and retainers  80  so as to store sufficient energy for holding retainers  80  and thus the ends of sheaths  44  against leg  78 , during movements of actuator  30  between the unlatching and latching positions under normal conditions as described above wherein pins  34  are freely movable, for moving cables  38  to move pins  34  between their unlatching and latching positions illustrated in  FIGS. 8 and 10 . 
       FIGS. 5 and 9  illustrate operation of biasing element  72  when a pin  34  is, or pins  34  are, stuck, i.e., obstructed, seized, jammed, in a position displaced in the latching direction, for instance, in hole  68  of receiver  66  ( FIG. 9 ), and a force is applied against actuator  30  to move it toward the unlatching position. Biasing element  72  accommodates this, by being resiliently yieldable to a sufficient level of applied force, and sheath  44  has sufficient flexibility and curvature, to allow sheath  44  and cable  18  to move as a unit, with actuator  30 . This allows actuator  30  to be moved to the unlatching position, while at the same time biasing element  72  is increasingly compressed to store an increased amount of energy, at least a substantial portion of which is exerted against the stuck pin or pins  34  in the unlatching direction as force F 2 , through cable  38 . Thus, if both pins  34  are stuck the force F 2  will be applied to each of them, by the compression of both biasing elements  72 . If only one pin is stuck, a single force F 2  will be applied to that pin only, as the other pin is already free to move in the unlatching direction. 
     Referring again to  FIGS. 4 and 5  and also to  FIG. 5A , if the applied force F 2  is insufficient to release the stuck pin or pins, bracket  32  preferably includes a detent mechanism  82  configured for utilizing force F 2  for holding actuator  30  in the unlatching position, to allow a user to move to another location to work to free the stuck pin or pins. For instance, this can be to hammer or pry the pin or pins free, or moving to an operator cab  94  ( FIG. 1 ) of the combine to operate a suitable control for moving the affected component, i.e., header  26 , feeder  22 , or both, to possibly relieve a force or loading condition causing the sticking. Detent mechanism  82  preferably utilizes a pin  84  of clevis  46  in connection with cables  38 , which pin  84  is received within and slidable along a slot  86  in structure  32 . Pin  84  also passes through a slot  88  through actuator  30 . Slots  86  and  88  are configured and cooperate to allow movement of actuator  30  between the latching and unlatching positions, which is an arcuate motion in this embodiment, without significantly bending cables  38 . Slot  86  additionally includes a detent receiver  90  ( FIG. 4 ) for cooperatively receiving pin  84  when actuator  30  is moved to the unlatching position, and pin  84  will be yieldably held in receiver  90  by force F 2 , which acts to hold actuator  30  in the unlatching position. When the pin or pins  34  is or are freed, force F 2  will drive the freed pin or pins in the unlatching direction, to the position shown in  FIG. 10 , and actuator  30  will remain lightly detained in the unlatching position by the remaining tension in the cable acting to hold pin  84  in receiver  90 . Alternatively, actuator  30  can be moved from the unlatching position with the latch pin or pins still stuck, by application of a sufficient force in opposition to force F 2  for removing pin  84  from receiver  90 . The configuration of slots  86  and  88  facilitate this by allowing movement of pin  84  by a small amount in the direction opposite that of force F 2 , sufficient for passage over detent protuberances  92  located at the juncture of slot  86  and detent receiver  90 . 
     It will be understood that changes in the details, materials, steps, and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention. For instance, the actuator herein described as a manually operated device, could alternatively be a foot operated, or machine operated device, such as a mechanical, electro-mechanical, electro-hydraulic, or hydraulic actuator device. Accordingly, the following claims are intended to protect the invention broadly as well as in the specific form shown.