Abstract:
An automatic attachment adapter adapted for coupling attachments to and uncoupling attachments from loader lift arms without the need for the operator to exit the equipment or employ a helper. The automatic attachment adapter employs a compact, lightweight, high strength latching device to make connection between the attachment plate of the loader and mounting plate of the attachment. By making use of interlocking rotating clevises the latching device is self-centering, requiring only approximate alignment to operate. Additionally, the latching mechanism is self cleaning of debris which may interfere with its operation.

Description:
RELATED APPLICATION 
     This application claims the benefit of Provisional Application No. 60/141,075 filed on Jun. 25, 1999, which is incorporated herein in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to adapters for connecting attachments to moving or lifting machinery. More particularly, the invention relates to an attachment plate and locking mechanism for securing attachments to construction equipment such as a skid steer loader. 
     BACKGROUND OF THE INVENTION 
     A wide variety of versatile motorized mobile base power units are used in the construction, maintenance, and grounds-upkeep industries. These include skid steer loaders, light tractors and other compact power units. Skid steer loaders, in particular, are widely employed for a variety of material handling, earth moving, and transportation tasks. 
     In general, these devices are favored for their compact size, maneuverability and versatility. The versatility of these units is largely dependent upon their ability to use a wide variety of available attachments. The variety of available attachments is enormous. Attachments include buckets, grapples, tree spades, backhoes and many others. 
     These attachments are interchangeable by virtue of a universal mounting plate on the attachment which is securable to an attachment plate on the lift arms of any given loader. Currently available attachment plates engage the attachment mounting plate by placing a beveled upper edge beneath a downward-angled flange on the mounting plate. Once the beveled edge is engaged under the downward-angled flange, a latching mechanism is secured to releasably attach the mounting plate to the attachment plate. 
     The latching mechanisms of currently available attachment plates are manually operated, and in general, engage a series of sliding bolts or pins on the attachment plate into a mating series of holes on the mounting plate. Thus, it is necessary for the operator of the equipment to shut down the equipment, exit the operator&#39;s position, and engage the latching mechanism manually, or to employ a helper to engage the latching mechanism manually. This situation creates a safety risk for the operator or helper, in that they must enter the operational area of the equipment while engaging the latching mechanism. The pins or bolts employed in these latching mechanisms are large and heavy in order to bear the substantial load stresses involved in operating the attachment. Additionally, precise alignment of the attachment plate and the mounting plate is required in order to engage the pins or bolts into their mating holes. If precise alignment is not achieved by manipulating the lift arms of the loader when engaging the attachment plate to the mounting plate, it is sometimes necessary for the operator or helper to manually shift the attachment, creating inconvenience and further safety risk. 
     Further, construction equipment is operated in an environment filled with dirt and debris. Items of dirt and debris may become lodged in the attachment latching mechanism, interfering with its operation. If this occurs the mechanism must often be cleaned manually, creating delay and inconvenience. 
     When it is desired to remove an attachment from the loader, it is necessary once again for the operator or helper to enter the operational area to manually disengage the latching mechanism, again creating inconvenience and a potential safety risk. It would be desirable to have an attachment plate and latching mechanism that is self-centering, requiring only approximate alignment with the mounting plate, and self-engaging, eliminating the need for manual intervention to latch the attachment plate to the mounting plate. In addition, it would be desirable to increase convenience and economy by making the attachment plate releasable without the need to employ a helper or for the operator to shut down and exit the machinery in order to release the attachment from the attachment plate of the loader. Further a self cleaning latching mechanism would be very helpful. 
     SUMMARY OF THE INVENTION 
     The present invention is an automatic attachment adapter which provides for safe, solo operation in the connection and removal of attachments from a skid steer loader or the like. The automatic attachment adapter employs a compact, lightweight, high strength latching device to make connection between the attachment plate of the loader and mounting plate of the attachment. Further, the latching device is self-centering, requiring only approximate alignment to operate. In addition, there is no need to enter the operational area of the equipment for manual engagement or disengagement of the latching mechanism, which creates a safer, more efficient, and more economical work environment. 
     This system employs a mounting plate on the attachment which has at its upper edge a downward-angled flange. Near the lower edge, it employs at least one pin to which the latching mechanism of the mating attachment plate engages. The attachment plate on the lift arms of the loader includes an angled upper edge for engaging the angled flange of the mounting plate and at least one latching mechanism which engages the pin on the mounting plate of the attachment. 
     The latching mechanism comprises a body housing and two rotating clevises which rotate on posts within the body housing. Each rotating clevis has a mouth, defined by an inner jaw and an outer jaw. The rotating clevises are able to be fully opened or to engage in one of two locking positions when closing. When open, the mouths of the paired rotating clevises overlap providing a relatively wide receiving area for receiving a mating pin for engagement. Once the engaging pin is in the receiving area, the rotating motion of the paired rotating clevises tends to force the pin to a centered location, creating a self-centering latch mechanism. 
     As the pin self-centers between the rotating clevises, the rotating clevises tend to close with relation to each other, achieving a first locked position, at which point the pin cannot be disengaged without unlocking the rotating clevises. Further travel inward reaches a second locked position, at which the mouths of the rotating clevises are fully meshed and the pin is engaged with great strength. This intermeshing of the rotating connectors creates a high-strength attachment between the attachment plate of the loader lift arms and the mounting plate on the attachment. 
     It is notable that once the beveled upper edge of the attachment plate is engaged beneath the angled flange of the mounting plate, the natural lifting motion of engaging the attachment causes the pins on the mounting plate to engage the latching mechanism rotating clevises, which encourages automatic engagement of the pins by the latching mechanism. 
     When it is desired to release the attachment from the loader, the latching mechanism can be remotely disengaged. The latching mechanism is well adapted to be disengaged by any of a variety of remote operating mechanisms. These mechanisms include a simple cable release, pneumatic mechanisms, hydraulic mechanisms, and electric servo-motor or solenoid mechanisms. 
     The latch mechanism is self cleaning. The rotating clevises are biased to an open position by springs or other biasing means. The opening motion of the latching mechanism tends to push debris out of the housing thus clearing it out of the mouths of the rotating clevises. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 a  is a side elevational view of an attachment plate of a loader beginning to engage the mounting plate of an attachment in accordance with the present invention; 
     FIG. 1 b  is a side elevational view of the attachment plate and mounting plate fully engaged; 
     FIG. 2 a  is a top plan view of a latching mechanism in the open position with the cover removed in accordance with the present invention, springs are not shown for clarity; 
     FIG. 2 b  is similar to FIG. 2 a  but with the latching mechanism in the first locked position; 
     FIG. 2 c  is a top plan view of a latching mechanism in the second locked position with the cover in place; 
     FIG.  3 . is a perspective view of a latching mechanism in the second locked position; and 
     FIG. 4 is a top plan view of an alternate embodiment of a latching mechanism in the second locked position with the cover removed. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 a  and  1   b,  an automatic attachment adapter  10  is adapted for connection to a mounting plate  12  secured to an attachment  14 . The adapter  10  is carried by attachment plate  16  secured to loader lift arms  18 . FIG. 1 a  depicts the mounting plate  12  and attachment plate  14  in a pre-engaged position. FIG. 1 b  depicts them in a fully engaged position. 
     Mounting plate  12  comprises a downward angled upper flange  20 , at least one engagement pin  22  and a lower flange  26 . Engagement pin  22  is operably connected to the back side  24  of mounting plate  12  and lower flange  26 . 
     Attachment plate  16  comprises an angled upper edge  28  adapted to fit beneath upper flange  20 , connection pivot axes  30  to loader lift arms  18 . At least one automatic latching device  32  is carried by the attachment plate  16 . 
     Referring to FIGS. 2 a,    2   b  and  2   c  an automatic latching device  32  generally includes: a housing  34 , an upper rotating clevis  36 , a lower rotating clevis  38 , a locking block  40 , a locking block release mechanism  42  and springs  44 . 
     The housing  34  includes a top portion  46  and a bottom portion  48 . The bottom portion  48  supports spring pivot posts  50 ,  52  and rotating clevis pivot posts  54 . The bottom portion  48  also presents an engagement pin receiving bay  56 . The top portion  46  is generally a mirror image mate to the bottom portion  48 , but presents bay  56  along with post receiving apertures  58 ,  60  and  62  aligned with spring pivot posts  50 ,  52  and rotating clevis pivot posts  54 , respectively. Referring to FIGS. 2 c  and  3 , the top portion  46  may also include release actuator  64  with release actuator pivot post  66 . Release actuator  64  may include remote actuator holes  68 . 
     Remote actuators may include any mechanism capable of applying a linear force to the release actuator  64  at remote actuator holes  68 . A remote actuator may also apply a rotational force directly to locking block release mechanism  42 . Remote actuators (not shown) may include a cable release, pneumatic mechanisms, hydraulic mechanisms, and electric servomotor or solenoid mechanisms. An optional manual release may be included as well. 
     Upper rotating clevis  36  and lower rotating clevis  38  are pivotably supported on respective pivot posts  54 . Each clevis presents an inner jaw  70  and an outer jaw  72  defining clevis mouths  74 . Clevis mouths  74  are U shaped with the semicircular portion of the U closely approximating the diameter D of engagement pin  22 . 
     As depicted in FIG. 3, the inner jaw  70  and outer jaw  72  of upper rotating clevis  36 , are milled on their bottom side  76  so that the jaws  70 ,  72  are about half of the overall thickness of the upper rotating clevis  36 . Likewise, the jaws  70 ,  72  of lower rotating clevis  38  are milled on their top side  78  to about one half the overall thickness of lower rotating clevis  38 . Upper rotating clevis  36  and lower rotating clevis  38  each include a first locking notch  80 , a second locking notch  82  and a spring receiving surface  84 . 
     The locking block  40  is pivotably coupled to locking block release  42 . In one embodiment of the invention, the locking block release  42  takes the form of a bellcrank  86  pivoting on spring pivot post  52 . In another embodiment (see FIG.  4 ), the release  42 ′ takes the form of a ramped slider  88 . Other types of locking block releases  42  may be employed without departing from the spirit and scope of the invention. 
     Referring to FIG. 2 a,  upper rotating clevis  36  and lower rotating clevis  38  are similar in structure but are oriented so that their upper and lower surfaces are reversed. Each includes a generally flat face  90  and a milled face  92  opposite the flat face  90 . The milled face  92  presents a first clearance notch  94 , a second clearance notch  96  and a spring clearance cutout  98 . The inner jaw  70  of each rotating clevis  36 , 38  presents an inward bevel  100  preferably of about 30 degrees. Upper rotating clevis  36  and lower rotating clevis  38  are positioned such that when in the open position, inner bevels  100  are substantially superimposed. Inner jaw  70  is dimensioned so that the depth of clevis mouth  74  relative to inner jaw  70  is about equal to diameter D. Outer jaw  72  is somewhat longer so that the depth of clevis mouth  74  exceeds diameter D substantially. Upper rotating clevis  36  and lower rotating clevis  38  each are capable of rotating through an angle greater than about forty five degrees from a closed position to an open position. Preferably, the angle of rotation is greater than about sixty degrees and most preferably about seventy degrees. 
     Locking block  40  has rounded corners  102  adapted to mate with first locking notches  80  and second locking notches  82 . Locking block  40  also presents boss  104  and pivot aperture  106 . 
     Bellcrank  86  presents an inner curve  108 , an outer rounded comer  110 , a locking block post  112 , and release actuator notch  114 . 
     Release actuator  64  further presents bellcrank finger  116  offset by bevel  118 . 
     In operation, referring to FIG. 1 a,  the angled upper edge  28  of attachment plate  16  is engaged below upper flange  20  of mounting plate  12 . Upon lifting the lift arms  18 , as depicted in FIG. 1 b,  it is noted that the normal lifting action tends to cause the lower portion of mounting plate  12  to approach lower portion of attachment plate  16  and to force engagement pin  22  toward mouths  74  of rotating clevises  36 , 38  of automatic latching mechanism  32 . 
     Referring to FIG. 2 a,  if engagement pin  22  approaches automatic latching mechanism  32  in an off center fashion, the intermeshing of mouths  74  of rotating clevises  36 , 38 , as they rotate, tends to force the engagement pin  22  into a centered position, as is apparent in FIGS. 2 b  and  2   c.  FIG. 2 b  depicts a first locked position of the automatic latching mechanism  22 . In this position, the outer jaws  72  of upper and lower rotating clevises  36 , 38  are closed with relation to housing  34  and engagement pin  22  is prevented from exiting their mouths  74 . Referring to FIG. 2 b  note that the opening receiving dimension R of overlapped clevis mouths  74  is at least twice as large as the diameter D of engagement pin  22 . Preferably, receiving dimension R is about three times as large as engagement pin diameter D. 
     Referring to FIG. 2 b,  locking block  40  engages into first locking notches  80  toward which it is biased by springs  44 , and prevents rotating clevises  36 , 38  from rotating outward until it is removed. This position serves as a safety feature holding the attachment plate  16  and mounting plate  12  together, if they are prevented, by an obstruction, from reaching a second locked position as depicted in FIG. 2 c.    
     Upon further inward travel of the engagement pin  22 , as depicted in FIG. 2 c,  the rotating clevises will achieve the second locked position. At this point, locking block  40  engages second locking notches  82  and the outer jaws  72  and inner jaws  70  of rotating clevises  36 , 38  are fully interlocked. Engagement pin  22  is securely positioned and cradled within bay  56 . At this point in the operation of automatic latching mechanism  32 , pin  22  is held with great strength and attachment plate  16  and mounting plate  12  are firmly secured together until locking block  40  is released by the operator. 
     When it is desired to remove the attachment  14  from the loader lift arms  18 , the machine operator manipulates a remote actuator (not shown) connected to the release actuator  64  at remote actuator holes  68 , which then applies a force to the release actuator  64  causing it to pivot about release actuator pivot post  66 . Locking block release mechanism  42  is thereby moved, overcoming the bias of springs  44 , and disengaging the locking block  40  from first or second locking notches  80 , 82 . Springs  44  then bias upper and lower rotating clevises  36 , 38  to rotate outward, thus releasing engagement pin  22 . Attachment plate  16  and mounting plate  12  may then be separated by manipulation of the loader lift arms  18 . 
     Referring to FIG. 4, in an alternate embodiment, the application of force by a remote actuator (not shown) applied to release actuator  64  is transmitted to a ramped slider assembly  88  which overcomes the bias of springs (not shown) to disengage locking block  40  from the locking notches  80 , 82 . Locking block  40  may be disengaged by other means without departing from the spirit and scope of the invention. 
     The opening of the mouths  74  of rotating clevises  36 , 38  by the bias of springs  44  tends to clear them of any debris that may be present thereby making the automatic latching mechanism self cleaning. 
     The present invention may be embodied in other specific forms without departing from the essential attributes thereof; therefore, the illustrated embodiments should be considered in all respects as illustrative and not restrictive, reference being made to the appended claims rather than to the foregoing description to indicate the scope of the invention.