Abstract:
An implement support frame or holder is mounted to an end of a boom for swinging about a horizontal, transverse axis. A pair of transversely spaced, tapered locating pins are mounted to a horizontal, transverse member of the support frame. The pins are each provided with a front surface that is curved on a radius about the transverse pivot axis and a gradually tapering rear surface. The pins are symmetrical about a fore-and-aft extending vertical plane with the curved forward surface acting to aid in guiding the pins into circular receptacles provided in an upper rear horizontal member of the implement.

Description:
FIELD OF THE INVENTION 
     The present invention concerns attaching implements to a support frame which is mounted to a boom end for pivoting freely about a horizontal transverse axis, and more specifically relates features of the support frame. 
     BACKGROUND OF THE INVENTION 
     In order to be able to attach front mounted implements, such as buckets, forks or the like, for free pivotal movement to the booms of tractor front end loaders, telescoping loaders or excavators, it is known practice to mount an implement holder or support frame to the boom of the operating machine for pivoting about a horizontal transverse axis. Arrangements for easy release of the front attached implements are provided on the support frame. 
     EP-A-0 398 110 discloses an arrangement for pivotally attaching a front attached implement to a boom of a loader. An implement holder is fastened over a rotary journal to the boom and can be pivoted about the rotary journal by a hydraulic cylinder. In the upper region of the holder, an upwardly opening, U-shaped receptacle is located which engages an upper transverse pin of the attached implement. The rotary journal projects on both sides of the holder so that its ends can engage receptacles in the implement that open to the rear. The rotary journals can be retained in the receptacles by a locking arrangement. For the mounting of the attached implement, the transverse pin is initially engaged by the support surface by movement of the holder. Then the holder is pivoted so that the ends of the rotary journals engage the receptacles. Following this, the ends of the rotary journals are locked in the receptacles. Here the lower attachment of the front attached implement to the support frame can be performed by a locking arrangement as has been described in DE-A-25 59 293. 
     It is also known practice from commercially available loaders to provide, in place of the support frame, a locating pin each that extends vertically upward and tapers to a cone shape, which engages in corresponding cylindrical recesses on the front attached implement. With this method of coupling, however, there is a disadvantage in that the vehicle must be positioned very precisely to the front attached implement in order to attain a secure coupling. Inappropriate handling could result in bending of the locating pin. 
     The task underlying the invention is seen in the need for defining a support frame and locating pin of the type defined above by means of which the aforementioned problems are overcome. 
     SUMMARY OF THE INVENTION 
     According to the present invention there is provided an improved implement holder or support frame of the type including a tapered locating pin. 
     It is an object of the invention to provide a support frame, having a locating pin, that is so constructed that the process of introducing the locating pin into a receptacle of a front attached implement is simplified to the extent that there is no need to precisely position the vehicle relative to the front attached implement in order to avoid damage to the locating pin. 
     A more specific object of the invention is to provide a support frame with a locating pin, as defined in the immediately preceding object, wherein the pin further includes a forward surface that is curved on a radius about the axis of the pivotal connection of the support frame with a boom of a work vehicle so that the support frame may be more easily manipulated to place the locating pin within a receptacle provided on the implement designed for attachment to the support frame. 
     These and other objects will become apparent from a reading of the ensuing description together with the appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a somewhat schematic right side elevational view of the boom of an operating machine with a support frame constructed in accordance with the present invention. 
     FIG. 2 is a front view of the support frame shown in FIG.  1 . 
     FIG. 3 is a front view of a locating pin of the present invention. 
     FIG. 4 is a side view of the pin shown in FIG.  3 . 
     FIG. 5 is a top view of the in shown in FIG.  3   
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, there is shown a boom  10  of an operating machine, not otherwise shown, which may be of a commercially available telescoping loader, for example. At the front end of the boom  10 , an implement support frame or holder  14  is fastened, free to pivot about a transverse pivot axis defined by a journal assembly  12 . The pivoting of the support frame  14  can be performed in the usual manner by one or two hydraulic cylinders, not shown. An attached or front implement  16 , shown only partially, for example, a shovel, is rigidly fastened to support frame  14 . 
     As can be seen from FIG. 2, two pins  18  project from the side of the lower region of the support frame  14 . When the front attached implement  16  is mounted, these pins  18  engage bores which extend transversely through vertical brackets  22  located at the rear of, and forming part of, the front attached implement  16 . For mounting or dismounting of the front attached implement  16 , the pins  18  can be retracted or extended in the axial direction by an appropriate arrangement as is revealed, for example, by DE-A 25 59 293. 
     On the upper edge of the support frame  14 , a locating pin  24  extending vertically upward is fastened to each side. The fastening can be performed, for example, by welding. Other methods of fastening, for example, by bolting are also possible. With this positioning of the locating pins  24 , the pins are easily visible from the vehicle cab and can be easily engaged in the receptacles of the front attached implement  16 . 
     Each locating pin  24  is provided with a mounting base  26 , in the form of a flange, and, vertically above that, an adjoining cylindrical region  28  of smaller diameter, which blends without any step into an essentially conical region  30 . The base  26  of the locating pin  24  is fastened to the support frame  14 . When the front attached implement  16  is mounted, the cylindrical region  28  engages a cylindrical bore that is defined in a bracket  32  extending generally in the horizontal direction in the rear, upper region of the implement  16 . 
     The locating pin mounting base  26  is generally cylindrical and is flattened on laterally opposite sides  34  and  36 . As can be seen from FIGS. 2 and 3, the profile of the conical region  30  of the locating pin  24  is configured symmetrically relative to a vertical plane  39 , extending fore-and-aft or in the direction of the boom  10 , and tapers towards the upper, free end  38  of the pin, generally in the form of a cone. Here the side edges  40  of the cone are not straight lines, but are curved slightly in the convex direction They include a mean taper angle α of approximately 35°. 
     As can be seen from FIG. 4, the profile of the conical region  30  of the locating pin  24 . is asymmetrical to a transverse vertical plane  42  bisecting the base  26  and cylindrical region  28 . The locating pin  24  tapers on its rear side  44 , which faces the boom  10 , only slightly towards the upper end, while the taper on the front side  46  is relatively strong. Here the tapered regions of the rear side  44  and the front side  46  are not straight lines, but are curved slightly in the convex direction. They include a mean taper angle β of approximately 30°. Hence, the locating pin  24  is not rotationally symmetrical, but is configured asymmetrically. However, the taper ratios with respect to the transverse cross section and the longitudinal cross section of the locating pin  24  are therefore in the same order of magnitude and differ relatively little from one another. This configuration leads to an optimum force distribution in the locating pins  24  since they have a relatively thick cross section throughout their tapered sections. 
     The above-described configuration of the locating pins  24  considerably improves the engagement of the front attached implement  16 . When the pins  24  are introduced into the respective receptacles of the front attached implement  16 , it is not necessary that the support frame  14  and the attached implement  16  be aligned precisely with each other. Due to the asymmetric configuration of the outer contour of the locating pins  24 , this shape conforms to the circular movement through which the support frame  14  moves during the process of positioning the pins  24  within the receptacles of the implement  16 . Due to this configuration, the front attached implement  16  can be engaged more rapidly, faster and safer. Evidence of wear and, in particular, bending of the location pins is largely avoided. 
     Preferably, the front side or flank  46  of the locating pin  24  forms essentially a circular arc whose radius R is equal to the distance between the front side  46  and the pivot axis  12  of the support frame  14 . During the engagement of the front attached implement  16 , the support frame  14  is pivoted about its pivot axis  12 . Due to the circular arc configuration of the front side  46 , this conforms optimally to the pivoting movement, so that during the engagement relative sliding between the support frame  14  and the front attached implement  16  can be largely avoided, whereby the locating pin  24  is loaded relatively little. 
     The upper region of the locating pin  24  approaches a ball shape, but at its outer most end region  38  it is configured with a slight flat. The circumferential outer contour of the locating pin  24  is rounded on all sides. Thereby pin cross sections that extend transverse to the axis  42  of the pin are essentially circular, as indicated in FIG.  5 . 
     In order to fasten the front attached implement  16  to the support frame  14 , the support frame  14  is lowered and the telescoping loader is maneuvered in such away that the locating pins  24  are positioned underneath the bores of the horizontal bracket  32 . Then the support frame  14  is pivoted upward about the pivot axis  12  whereupon the locating pins  24  enter the bores and the upper edge of the support frame  14  lifts the front attached implement  16 . As soon as the side pins  18  are aligned with the associated bores of the vertical brackets  22 , they are extended and engage these bores and lock the front attached implement  16  to the support frame  14 . 
     Although the invention has been described in terms of only one embodiment, anyone skilled in the art will perceive many varied alternatives, modifications and variations in light of the above description as well as the drawing, all of which fall under the present invention. 
     Having described the preferred embodiment, it will become apparent that various modifications can be made without departing from the scope of the invention as defined in the accompanying claims.