Hydraulic latch pin assembly for coupling a tool to a construction equipment

Abstract

The invention provides a coupling assembly for coupling a tool to a dipperstick, or arm, on an apparatus which has a hydraulic system for moving the tool. The coupling assembly includes a coupler body having a frame that defines a central cavity, and also having link structure for pivotally coupling to the dipperstick. An actuator assembly positioned within the central cavity includes a latch pin that can slide between an engaged position and a retracted position. In the engaged position, an end of the latch pin projects out from a rear end of the frame for engaging a receptacle defined by the tool. In the retracted position, the end of the latch pin does not project out from the frame. A bias structure normally urges the latch pin toward the engaged position with a bias force. A hydraulic latch cylinder has a fixed part and a movable part rigidly coupled to the latch pin such that, when the movable part is extended from the fixed part, the latch pin is urged to the retracted position.

What is claimed is:  
     
       1. A coupling assembly for coupling a tool to an arm of an apparatus, wherein tilting of the coupling assembly from the arm is powered by a hydraulic system, the coupling assembly comprising: 
       a coupler body, including a frame defining a central cavity, and link structure for pivotally coupling the arm to the tool; and  
       an actuator assembly attached to the frame, the actuator assembly including:  
       a latch pin movable between an extended position for engaging a receptacle defined by the tool, and a retracted position for disengaging from the receptacle;  
       a hydraulic latch cylinder having a fixed part and a movable part that can be extended relative to the fixed part; and  
       a latch pin coupling assembly coupling between the latch pin and the movable part such that extension of the movable part urges the latch pin to the retracted position.  
     
     
       2. The coupling assembly of claim  1 , wherein the latch pin coupling assembly comprises a bias structure that urges the latch pin towards the extended position with a bias force. 
     
     
       3. The coupling assembly of claim  2 , wherein the bias structure includes a compression spring positioned between a second end of the latch pin and an end plate fixed within the frame. 
     
     
       4. The coupling assembly of claim  1 , further comprising a hydraulic switch assembly operably coupling hydraulic pressure from the hydraulic system to the latch cylinder. 
     
     
       5. The coupling assembly of claim  4 , wherein the hydraulic switch assembly includes a solenoid valve assembly structured and arranged to couple hydraulic pressure to the latch cylinder when energized and to release hydraulic pressure from the latch cylinder when de-energized. 
     
     
       6. The coupling assembly of claim  5 , wherein the hydraulic switch assembly further includes a system that produces a warning signal indicative of the valve assembly being energized. 
     
     
       7. The coupling assembly of claim  1 , wherein the actuator assembly includes an indicator member coupled to the latch pin and visible from outside the frame by an operator of the apparatus such that the position of the indicator member indicates the position of the latch pin to the operator. 
     
     
       8. The coupling assembly of claim  1 , wherein the coupler body further comprises a hook depending from the frame and projecting towards a forward end thereof and structured for engaging mating structure formed in the tool. 
     
     
       9. The coupling assembly of claim  1 , wherein the latch cylinder is positioned on an axis different from an axis defined by the latch pin. 
     
     
       10. The coupling assembly of claim  1 , wherein the latch cylinder is a single-action cylinder. 
     
     
       11. A latch pin actuator assembly for urging a latch pin of a tool coupler into and out of engagement with a mating receptacle formed in a tool, the actuator assembly comprising: 
       a hydraulic latch cylinder having a fixed part and a movable part that extends from the fixed part when hydraulic pressure from a hydraulic system is applied to the latch cylinder; and  
       a latch pin coupling assembly adapted to couple between the latch pin and the movable part of the latch cylinder structured and arranged to retract the latch pin to a retracted position for disengaging the latch pin from the receptacle when the movable part is extended.  
     
     
       12. The actuator assembly of claim  11 , wherein the latch pin coupling assembly comprises a bias member structured and arranged to urge the latch pin towards the extended position with a bias force. 
     
     
       13. The actuator assembly of claim  12 , wherein the bias member includes a compression spring adapted to be positioned between a second end of the latch pin and an end plate within the frame. 
     
     
       14. The actuator assembly of claim  11 , further comprising a hydraulic switch assembly operably coupling hydraulic pressure from the hydraulic system to the latch cylinder. 
     
     
       15. The actuator assembly of claim  14 , wherein the hydraulic switch assembly includes a solenoid valve assembly structured and arranged to couple hydraulic pressure to the latch cylinder when energized and to release hydraulic pressure from the latch cylinder when de-energized. 
     
     
       16. The actuator assembly of claim  15 , wherein the hydraulic switch assembly further includes a system that produces a signal indicative of the valve assembly being energized. 
     
     
       17. The actuator assembly of claim  11 , further including an indicator member coupled to the latch pin and visible from outside the tool coupler such that the position of the indicator member is indicative of the position of the latch pin. 
     
     
       18. The actuator assembly of claim  11 , wherein the latch cylinder is positioned on an axis different from an axis defined by the latch pin. 
     
     
       19. The actuator assembly of claim  11 , wherein the latch cylinder is a single-action cylinder. 
     
     
       20. The actuator assembly of claim  12 , wherein the bias member and the latch cylinder are selected such that approximately full hydraulic pressure from the hydraulic system is required for latch cylinder overcome the bias force and retract the latch pin. 
     
     
       21. A tool coupler for coupling an excavation to an apparatus for operating the excavation tool, the apparatus including a base, a hydraulic system in the base with controls for distributing hydraulic pressure from the hydraulic system, a movable dipper stick having a free end, and a hydraulic tool cylinder hydraulically coupled to the hydraulic system, the tool coupler comprising: 
       a frame, including side walls and cross members that define a central space, a dipper pivot at a forward end of the frame for pivotally connecting to the free end of the dipper stick, and a link pivot located rearward from the dipper pivot for pivotally coupling to an end of the tool cylinder, wherein extension of the tool cylinder rotates the frame forward around the dipper pivot;  
       forward extending hook structure depending from the frame, structured and arranged to engage a cross member located at an upper and forward portion of the tool;  
       an actuator assembly attached to the frame, the actuator assembly including: a latch pin located substantially within the central space and movable between an extended position wherein a first end of the latch pin projects out from a rear end of the frame for engaging a receptacle formed in the excavation tool, and a retracted position for disengaging from the receptacle of the excavation tool; a bias member structured and arranged to apply a bias force to the latch pin urging the latch pin towards the extended position; a hydraulic latch cylinder having a fixed part and a movable part that can be extended from the fixed part; and a latch pin coupling assembly coupling between the latch pin and the movable part such that extension of the movable part urges the latch pin to the retracted position; and  
       a hydraulic switch assembly operably coupling hydraulic pressure from the hydraulic system to the latch cylinder.  
     
     
       22. The coupling assembly of claim  21 , wherein the hydraulic switch assembly includes a solenoid valve assembly that couples hydraulic pressure from the tool cylinder to the latch cylinder when energized and that permits release of hydraulic pressure from the latch cylinder when de-energized. 
     
     
       23. The coupling assembly of claim  21 , wherein the latch cylinder is positioned on an axis different from an axis defined by the latch pin. 
     
     
       24. The coupling assembly of claim  21 , wherein the latch cylinder is a single-action cylinder. 
     
     
       25. A method for coupling an excavation tool to a coupler body pivotally attached at an end of an arm, the coupler body including a latch pin capable of sliding between an engaged position with an end of the latch pin projecting out from the coupler body and a retracted position with the end not projecting out from the coupler body, the method comprising: 
       applying hydraulic pressure to a latch cylinder that has a part fixed relative to the coupler body and a movable part coupled to the latch pin;  
       extending the movable part relative to the fixed part, thereby urging the latch pin to the retracted position;  
       engaging a cross member of the excavation tool with a hook structure depending and extending forward from the coupler body;  
       rotating the coupler body toward the tool, aligning the latch pin with a mating receptacle formed in the excavation tool;  
       reducing the hydraulic pressure to the latch cylinder; and  
       applying a bias force to the latch pin, urging the latch pin to the engaged position, thereby engaging the latch pin in the receptacle and securing the excavation tool to the coupler body.  
     
     
       26. The method of claim  25 , wherein applying hydraulic pressure includes applying sufficient hydraulic pressure for the cylinder to overcome the bias force. 
     
     
       27. The method of claim  26 , wherein applying hydraulic pressure includes energizing a solenoid actuated valve to couple hydraulic pressure from a hydraulic cylinder for rotating the coupler body to the latch cylinder. 
     
     
       28. The method of claim  27 , further comprising providing a signal indicative that the solenoid valve is energized. 
     
     
       29. The method of claim  25 , further comprising providing a visible indication of when the latch pin is retracted. 
     
     
       30. The method of claim  25 , further comprising removing the tool, including: 
       rotating the coupler body and the tool to a full forward position;  
       again applying hydraulic pressure to the latch cylinder;  
       again extending the movable part from the fixed part, thereby urging the latch pin to the retracted position and disengaging the latch pin from the receptacle; and  
       disengaging the hook structure from the cross member of the excavation tool.  
     
     
       31. A coupling assembly for coupling a bucket to a dipperstick of an hydraulic equipment, the coupling assembly comprising: 
       a frame structured for attachment to the dipperstick and including an aperture formed by an underside;  
       an actuator assembly in the frame, including a latch pin, the actuator assembly structured to move a latch pin between an engaged position engaged with a mating structure of the bucket and a retracted position disengaged from the mating structure; and  
       an indicator member coupled to the latch pin and movable therewith, wherein the indicator member is visible through an opening of the bucket and through the aperture from outside the frame by an operator of the equipment such that the position of the indicator member indicates the position of the latch pin to the operator.  
     
     
       32. A method of operating a bucket from a free end of a dipperstick of an excavation equipment, comprising: 
       providing a coupler at the free end of the dipperstick, the coupler including a body and latch pin capable of sliding between an engaged position with an end of the latch pin projecting out from the coupler body and a retracted position with the end of the latch pin retracted within the coupler body;  
       attaching a bucket to the coupler by moving the coupler pin to the engaged position engaged with a mating structure of the bucket; and  
       viewing an indicator member, coupled with the latch pin, through an opening of the bucket when the latch pin is moved to a retracted position disengaged from the mating structure.  
     
     
       33. A coupling assembly for coupling a tool to an arm of an apparatus, wherein tilting of the coupling assembly from the arm is powered by a hydraulic system, the coupling assembly comprising: 
       
         a coupler body, including a frame defining a central cavity, and link structure for pivotally coupling the arm to the tool; and  
       
       
         an actuator assembly attached to the frame, the actuator assembly comprising:  
       
       
         a latch pin movable between an extended position for securing the tool to the arm, and a retracted position for releasing the tool;  
       
       
         a hydraulic latch cylinder having a fixed part and a movable part that can be extended relative to the fixed part; and  
       
       
         a latch pin coupling assembly coupling between the latch pin and the movable part such that extension of the movable part urges the latch pin to the retracted position. 
       
     
     
       34. The coupling assembly of claim  33 , wherein the latch pin coupling assembly comprises a bias structure that urges the latch pin towards the extended position with a bias force. 
     
     
       35. The coupling assembly of claim  34 , wherein the bias structure comprises a compression spring positioned between an end of the latch pin and an end plate fixed within the frame. 
     
     
       36. The coupling assembly of claim  33 , further comprising a hydraulic switch assembly operably coupling hydraulic pressure from the hydraulic system to the latch cylinder. 
     
     
       37. The coupling assembly of claim  36 , wherein the hydraulic switch assembly comprises a solenoid valve assembly structured and arranged to couple hydraulic pressure to the latch cylinder when energized and to release hydraulic pressure from the latch cylinder when de- energized.   
     
     
       38. The coupling assembly of claim  37 , wherein the hydraulic switch assembly further comprises a system that produces a warning signal indicative of the valve assembly being energized. 
     
     
       39. The coupling assembly of claim  33 , wherein the actuator assembly comprises an indicator member coupled to the latch pin and visible from outside the frame by an operator of the apparatus such that the position of the indicator member indicates the position of the latch pin to the operator. 
     
     
       40. The coupling assembly of claim  33 , wherein the coupler body further comprises a hook depending from the frame and projecting towards a first end thereof and structured for engaging mating structure formed in the tool. 
     
     
       41. The coupling assembly of claim  33 , wherein the latch cylinder is positioned on an axis different from an axis defined by the latch pin. 
     
     
       42. The coupling assembly of claim  33 , wherein the latch cylinder is a single- action cylinder.   
     
     
       43. A tool coupler for coupling an excavation tool to an apparatus for operating the excavation tool, the apparatus including a base, a hydraulic system in the base with controls for distributing hydraulic pressure from the hydraulic system, a movable dipper stick coupled to the base and having a free end, and a hydraulic tool cylinder hydraulically coupled to the hydraulic system and having one end pivotally linked to the dipper stick at a location spaced apart from the free end of the dipper stick, the tool coupler comprising: 
       
         a frame, comprising side walls and cross members that define a central space, a dipper pivot at a forward end of the frame for pivotally connecting to the free end of the dipper stick, and a link pivot located rearward from the dipper pivot for pivotally coupling to a second end of the tool cylinder, wherein extension of the tool cylinder rotates the frame forward around the dipper pivot;  
       
       
         a hook structure depending from the frame, structured and arranged to engage a cross member located at a first end of the tool;  
       
       
         an actuator assembly attached to the frame, the actuator assembly comprising: a latch pin located substantially within the central space and movable between an extended position wherein a first end of the latch pin secures a mating structure of the excavation tool to the tool coupler, and a retracted position for releasing the mating structure of the excavation tool from the tool coupler; a bias member structured and arranged to apply a bias force to the latch pin urging the latch pin towards the extended position; a hydraulic latch cylinder having a fixed part and a movable part that can be extended from the fixed part; and a latch pin coupling assembly coupling between the latch pin and the movable part such that extension of the movable part urges the latch pin to the retracted position; and  
       
       
         a hydraulic switch assembly operably coupling hydraulic pressure from the hydraulic system to the latch cylinder. 
       
     
     
       44. The coupling assembly of claim  43 , wherein the hydraulic switch assembly includes a solenoid valve assembly that couples hydraulic pressure from the tool cylinder to the latch cylinder when energized and that permits release of hydraulic pressure from the latch cylinder when de- energized.   
     
     
       45. The coupling assembly of claim  43 , wherein the latch cylinder is positioned on an axis different from an axis defined by the latch pin. 
     
     
       46. The coupling assembly of claim  43 , wherein the latch cylinder is a single- action cylinder.   
     
     
       47. A method for coupling an excavation tool to a coupler body pivotally attached at the end of an arm, the coupler body comprising a latch pin capable of sliding between an extended position and a retracted position, the method comprising: 
       
         applying hydraulic pressure to a latch cylinder that has a part fixed relative to the coupler body and a movable part rigidly coupled to the latch pin;  
       
       
         extending the movable part relative to the fixed part, thereby urging the latch pin to the retracted position;  
       
       
         engaging a cross member of the excavation tool with a hook structure depending and extending from the coupler body;  
       
       
         rotating the coupler body toward the tool to position a mating structure of the tool to be secured by the latch pin;  
       
       
         reducing hydraulic pressure to the latch cylinder; and  
       
       
         applying a bias force to the latch pin, urging the latch pin to the extended position to secure the mating structure, and thereby the excavation tool, to the coupler body. 
       
     
     
       48. The method of claim  47 , wherein applying hydraulic pressure includes applying sufficient hydraulic pressure for the cylinder to overcome the bias force. 
     
     
       49. The method of claim  48 , wherein applying hydraulic pressure includes energizing a solenoid actuated valve to couple hydraulic pressure from a hydraulic cylinder for rotating the coupler body to the latch cylinder. 
     
     
       50. The method of claim  49 , further comprising providing a signal indicative that the solenoid valve is energized. 
     
     
       51. The method of claim  47 , further comprising providing a visible indication of when the latch pin is retracted. 
     
     
       52. The method of claim  47 , further comprising removing the tool, including: 
       
         rotating the coupler body and the tool to a full forward position;  
       
       
         again applying hydraulic pressure to the latch cylinder;  
       
       
         again extending the movable part from the fixed part, thereby urging the latch pin to the retracted position and releasing the mating structure of the excavation tool; and  
       
       
         disengaging the hook structure from the cross member of the excavation tool.