Abstract:
A power operated apparatus to latch an attachment to a loader arm of a skid steer vehicle having an attachment frame with a pair of spaced apart latch pins slidably mounted on the frame to move between a latched and an unlatched position to either lock in place or release a loader attachment to the attachment frame. Each latch pin is operatively connected to an axially slidable piston rod of a hydraulic actuator which moves the latch pin between a latched and an unlatched position in response to manipulation of controls by an operator in the vehicle cab.

Description:
FIELD OF THE INVENTION 
     This invention relates to power actuated quick attachment devices for accessories or work implements on skid steer vehicles, to eliminate hand operated latches on such attachment devices. 
     BACKGROUND OF THE INVENTION 
     In the past various quick attachment devices have been developed for skid steer loaders. U.S. Pat. Nos. 3,732,996 and 3,672,521 show quick attachment devices that are carried on the front of a loader arm and are used for quickly attaching and detaching various accessories, such as different types of buckets or grapples. These quick attachment devices have been utilized extensively by Melroe Company, a Business Unit of Clark Equipment Company and sold under the trade name BOBTACH. 
     Power operated, quick attachment devices have been also advanced in the past, such as the device shown in U.S. Pat. No. 3,269,570. Also a power operated device for backhoes is illustrated in U.S. Pat. No. 5,107,610. 
     A skid steer loader adapter for an implement mounting plate is shown in U.S. Pat. No. 5,098,252 and uses a spring biased mechanism that is biased toward a retracted or released position. An over center wedging mechanism engages hook members to overcome a spring force and the locking mechanism is forced into engagement with the implement being mounted. 
     U.S. Pat. No. 5,562,397 shows a way of adapting the BOBTACH system to power operation by attaching a power actuator between an existing pair of hand levers which move a respective pair of latch pins or wedge members to a retracted or an extended position. The power actuator is retracted or extended between the hand levers to move them into position to retract or extend the latch pins. 
     The present invention simplifies the assembly by reducing the number of working parts and eliminates the hand levers by connecting a power actuator directly to each latch pin. In addition cover members are provided for all the working parts of the latch pins and actuators to prevent dirt and debris from clogging up the equipment and interfering with reliable operation of the latch pins. 
     SUMMARY OF THE INVENTION 
     This invention relates to a power operated apparatus to latch an attachment to a loader arm of a skid steer vehicle comprising: an attachment frame including at least one latch slidably attached thereto and which slidably moves to a latched position to hold an implement on the attachment frame and at least one power operated actuator having a fixed portion attached to the attachment frame and an elongated moveable portion having one end slidably engaging the fixed portion and an opposite end attached to the latch to cause the latch to move to either a latched or unlatched position depending upon the direction of movement of the moveable portion, a power source associated with the actuator causing sliding movement of the moveable portion to an extended or retracted position with respect to the fixed portion and control means to regulate power provided to the actuator. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational view of an attachment plate having power actuators for moving latch pins in a longitudinal direction; 
     FIG. 2 is a side elevational view of a typical quick attachment system with which the power actuator of the present invention is used showing an attachment prior to being positioned on a mounting plate on loader arms of a skid steer vehicle; 
     FIG. 3 is a fragmentary perspective view of one end of the mounting plate on the loader arms in position adjacent the attachment to be mounted; 
     FIG. 4 is a fragmentary perspective view showing the attachment mounted on the plate, with a latch pin in an extended position to hold the attachment in place; 
     FIG. 5 is a side view of the attachment plate of the loader with parts in section and parts broken away to show the power actuator holding the latch pin in the extended position; 
     FIG. 6 is a greatly enlarged view of the latch pin assembly attached to a piston rod of a power actuator; 
     FIG. 7 is a perspective view of the attachment plate pivoted down into a horizontal position to show how the cover members fit on the attachment plate to enclose the moving parts of the actuators and latch pins for protection from dirt and debris; and 
     FIG. 8 is a side elevational view showing a latch position indicator flag which is attached to a piston rod as shown in FIG.  6 . 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in FIG. 2, a loader arm  10  of conventional construction has an attachment mounting plate  12  pivotally mounted on the arm about pivots  14 . The tilting of the attachment plate  12  is controlled by an actuator, the extensible and retractable rod of which is shown as  16 , attached to a suitable bracket  18  on the attachment mounting plate  12 . As can be seen in FIG. 2, the attachment mounting plate  12  includes a lip  20  that will fit under a flange  22  on an attachment such as a loader bucket indicated at  24 . There is a flange on the lower edge of the back wall on each side of the bucket. One side of the attachment plate is shown for sake of illustration. A lower flange  26  is also supported on the attachment or bucket  24 , and as can be seen the lower flange  26  has an aperture  28  that will align with an aperture  30  in a lower support flange  32  of the attachment mounting plate or frame  12 . A sliding latch pin or wedge  34  is mounted in a suitable guide plate (or plates)  36  that forms part of a latch pin and actuator housing  37  on the attachment mounting plate  12 . The latch pin  34  will move up or down in a vertical direction. As can be seen, the latch pin has a tapered wedge end  38 , to aid in pushing the wedge or latch pin  34  into the desired aperture on the attachment or bucket  24  when it is in position to be mounted. The latch pin  34  also has a shaft portion  39  that is slidably guided in suitable guides. 
     As best seen in FIG. 6, the upper end of shaft portion  39  of latch pin  34  is pivotally mounted to a conventional latch pin actuator shaft assembly  40 , which has a housing  43  at the lower end. The housing  43  has a bifurcated end  44  that receives a pivot pin  46  used for coupling the housing  43  to the end of shaft portion  39  of latch pin  34 . 
     A coupling end  50  is connected to a shaft member  42  that is slidably coupled to the housing  43 . A spring  48  acts between an adjusting nut  49  and coupling end  50  at the upper end of the telescoping shaft assembly  40 . The arrangement is conventional and will load the latch pin or wedge downward to lock the latch pin as well as upward. 
     The upper ends of each of the shaft assemblies  40  are each connected to an L-shaped bracket  52  respectively on opposite sides of the attachment mounting plate  12 . The shaft assemblies  40  and the latch pins are identical on the opposite sides of the attachment mounting plate  12 . The coupling end  50  on each latch pin carries a pivot pin  54  which passes through a hole  56  in the bracket  52  and enables each bracket  52  to pivotally engage the latch pin  34 . A bolt  58  holds the coupling end  50  in position on the end of the shaft member  42 . 
     A bolt  60  passes through a hole  62  in a latch pin position indicator  64  and a hole  66  in the bracket  52  and attaches both the bracket  52  and the indicator  64  to the end of a piston rod  68  protruding from a hydraulic cylinder  69  of a hydraulic actuator  70 . The hydraulice cylinder  69  is fixedly attached to the attachment mounting plate  12  by blocks  71 . Instead of blocks brackets could also be used. 
     The entire indicator  64  is shown in FIG. 8 in which it is shown projecting through an opening  72  in a cover member  74  which is shown in its entirety in FIG.  7 . The cover member  74  has holes  74   a  through which bolts (not shown) pass and are attached to matching threaded holes  37   a  in the actuator housing  37 . A shaded portion  72  of the length of the indicator  64  (indicated by stippling) may be painted a bright color such as orange or red to make it readily visible when it is protruding through the opening  72 . When the piston rod  68  moves to an extended position to raise the latch pin  34  to an unlatched position, this also moves the indicator  64  so that the bright colored portion  76  is visible on the outside of the cover  74 . When the piston rod  68  is retracted, the latch pin  34  is moved to a latched position and the bright colored portion  76  is moved inside the cover  74  and is no longer visible. This indicates to the operator of the vehicle that the latch pin is in the latched or engaged position to hold an attachment on the attachment mounting plate. For simplicity of the drawings, the indicators  64  have only been shown on FIGS. 6 through 8. In can be seen that this indicators  64  can also be attached to the piston rods  68  shown on all the other figures of the drawings. 
     As shown in FIG. 1 hydraulic lines  78  and  80  are controlled by valves  78   a  and  80   a  respectively to regulate the flow of hydraulic fluid pressure to the actuators  69 . Suitable controls for the valves can be located in the operators cab of the vehicle. Each of the lines  78  and  80  divides off and runs through a transverse channel  82  to supply fluid to both the cylinders  69 . For simplicity of the drawing the lines  78  and  80  are not shown connected to the cylinders  71  of the actuators  70 , however in operation, line  78  connects to ports  78   b  to cause retraction of piston rods  68  and line  80  connects to ports  80   b  to cause extension of piston rods  68 . By changing the pressure from one end of the cylinder  69  to the other, each of the piston rods  68  move axially in an out of its respective cylinder to move its respective latch pin up and down between a latched and unlatched position. 
     Referring to FIG. 7, a channel cover  84  is fastened to the channel  82  by passing screws (not show) through holes  86  into matching holes (not shown) in channel  82 . Identical covers  74  are attached to the housing  74  on each side of the mounting plate  12 . Both covers  74  and the cover  84  prevent dirt and debris from clogging up the operation of the latch pins  34  and the actuators  70 . 
     In operation, the piston rod  68  of each power actuator  70  is moved to an extended position, so that the latch pins  34  are moved to a raised unlatched position. The attachment frame  12  is moved from a position shown in FIGS. 2 and 3 to a position adjacent to the attachment  24  such as a loader bucket in the same manner as is done conventionally such as shown in FIGS. 4 and 5. The attachment frame  12  is tilted forwardly so that the lip  20  is placed under the attachment flanges  22 . The rod  16  of the tilt cylinder on the skid steer loader is retracted and the bottom portion of the attachment frame will move into the receptacle formed above the lower flanges  26  on the attachment  24 . The attachment frame  12  is positioned with the latch pins  34  aligned with the respective apertures  28  so that the latch pins  34  will be in position to lock in place. 
     Once the attachment frame  12  has been put into position relative to flanges  22  and  26 , the piston rods  68  of the power actuators  70  can be retracted to extend to move the latch pins  34  downwardly to a latched position with the ends of the latch pins  34  being forced through the apertures  28  on the flange  28  of the attachment  24 , to positively lock the attachment into position on the attachment frame  12 . Then the loader can be used in the normal manner. 
     To release the attachment  24 , the actuator  70  is operated in an opposite direction to extend the piston rods  68  and thereby retract the latch pins  34  to a raised unlatched position. The attachment frame  12  can then be tilted forwardly to pull the bottom portion of the frame  12  away from the flange  26 . Lowering the attachment frame  12  will pull the lip  20  away from the flange  22  for complete release of the frame  12  from the attachment  24 . 
     While the actuator  70  is shown as a hydraulic actuator, it could also be an electric actuator or other type device if desired. The term actuator as used herein means any type of power actuator that provides for extension and retraction under control of an operator to cause movement of the latch pins  34  between a latched an unlatched position. This actuator can be retrofited into existing equipment to replace hand lever operated latch pins. 
     Various other modifications can be made in the present invention without departing from the scope of the invention.