Abstract:
A quick-convert bucket attachment for front end loaders has hydraulically positioned, interlocking bucket components that may be manipulated by controls at the tractor seat or other convenient location for rapid conversion of the attachment from a general purpose loading bucket to a side-shift angle dozer. The back wall of the bucket is formed by the dozer blade, while the side walls and floor of the bucket are formed by a clam which may be raised into an elevated position to expose the dozer, at which time the dozer may be either maintained in a centered, straight-forward position or shifted laterally into a left or right, obliquely angled position. The dozer blade is completely immobilized and is held solidly against a main base of the attachment when the clam is in its lowered position, thus presenting a rugged bucket capable of functioning in all respects as a conventional loader bucket at that time.

Description:
TECHNICAL FIELD 
     This invention relates to front end loader attachments and, more particularly, to an attachment which is quickly and easily converted between a standard loading bucket configuration and a side-shift angle dozer configuration without the operator leaving the tractor seat. 
     BACKGROUND OF THE INVENTION 
     Having a loader equipped with a loading bucket permits the operator to scoop up loose materials, carry them a short distance and then dump them onto the ground or into a receptacle. Such buckets are very versatile and are used in a wide variety of earth moving and material handling jobs with great success. 
     However, there are some jobs for which the bucket is simply not well-suited. For example, when back-filling a ditch, using the essentially single purpose bucket to perform that task is tedious and inefficient, and frequently produces poor quality results. In order to return the long windrow or &#34;spoil&#34; of dirt to the ditch from a position alongside the ditch, the operator must repeatedly maneuver the tractor back and forth at an angle to the ditch, pushing and shoving the spoil pile into the open ditch while at the same time twisting and turning the vehicle which tears up the soil and grass in the vicinity. Much time is consumed in the process and the end result is not a particularly neat or professional-looking job. 
     Instead of the bucket, it would be better for the operator to use an angled dozer blade which has also been shifted laterally from a centered position so that the operator only needs to drive along the ditch in a parallel path of travel while engaging the line of spoil with the angled dozer blade and thus continually diverting the spoil directly into the ditch as the tractor moves along. However, while such side-shift-angle dozer attachments are currently commercially available, they are intended for use only after the bucket has first been removed from the loader arms, leaving a place for the side-shift dozer blade to be attached in their absence. While such interchanging of the standard buckets and side-shift-angle dozer attachments is theoretically quite possible, as a practical matter the standard bucket is seldom replaced with the dozer attachment because it is a cumbersome, time consuming and difficult task to do so. For one thing, the massive weight of the attachments themselves makes such interchanging job a considerable effort for one man to accomplish. Furthermore, the side-shift-angle dozer is usually only required for a relatively short period of time, whereupon it becomes necessary to reverse the procedure and detach the dozer blade and hook up the bucket. As a consequence, operators simply tend to make do with the bucket alone and leave the side-shift dozer blade back at the shop, even though use of the bucket for dozing, backfilling, and clean-up work has a number of disadvantages, as discussed above. 
     SUMMARY OF THE PRESENT INVENTION 
     Accordingly, one important object of the present invention is to provide a loader attachment which, without requiring detachment from the loader arms, is quickly and easily convertible from a standard bucket configuration to a side-shift-angle dozer configuration without requiring the operator to leave the tractor seat. In other words, instead of requiring that the operator take off the standard bucket and replace it with a side-shift-angle dozer, the present invention contemplates that the operator may simply operate the appropriate controls at the tractor seat to literally transform the bucket into a side-shift-angle dozer, and back again, by moving certain components of the attachment into and out of different operating positions and relationships with one another. 
     In carrying out the foregoing object, the present invention contemplates having a bucket in which the back wall doubles as the dozer blade and the sides and bottom wall are connected together to form what may be termed a &#34;clam&#34; that can be swung up out of the way to expose the dozer blade. Once the clam is raised, the dozer blade can be shifted laterally and cocked into an obliquely angled orientation to perform its dozing functions. The bucket configuration is quickly reestablished by simply returning the dozer blade to its centered, squared up position and then lowering the clam back down into close proximity to the dozer blade so that it once again becomes the back wall of the reestablished bucket. If desired, once the clam is raised, the dozer blade may be maintained in its straight forward position to simply shove the materials forwardly, and the clam may be used in cooperation with the straight ahead blade to clamp logs or other objects against the dozer blade so that the loader can be utilized to pick up, grip and carry such objects from one position to another. 
     In its preferred form, the convertible attachment of the present invention has a sturdy, rugged base that is connected directly to the lift arms of the loader and serves as the foundational member upon which all other components of the attachment are mounted. Thus, instead of the clam being mounted on and carried by the dozer blade, it is attached directly to the base component and stays behind in a straight forward, although raised, position when the dozer blade is shifted into either of its left or right, side-shifted, obliquely angled positions. When the dozer blade is back in its original squared-up position, and the clam is lowered to present a bucket configuration, the clam effectively clamps the dozer blade against the base member and provides a very rugged, general purpose bucket that will withstand the rigors of heavy use in spite of being formed from a plurality of separate components that are readily separable to transform the bucket into a different configuration. 
     While the prior art has included a variety of attachments which could be converted between standard bucket and clam configurations, and while side-shift-angle dozers have heretofore been available, to my knowledge no one has previously provided a convertible bucket which may be quickly and easily transformed into a side-shift-angle dozer, and vice-versa. As an example of a bucket having a clam which can be raised to expose a dozer blade, see the Drott U.S. Pat. No. 2,812,595. For a disclosure of a side-shift-angle dozer attachment, see, for example, my own prior U.S. Pat. No. 3,759,110. U.S. Pat. No. 4,890,400 to Long shows a bucket which can be manually swiveled into an obliquely angled position and the side and bottom walls of the bucket raised in the nature of a clam to expose the back wall as a dozer blade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a right side elevational view of a front end loader equipped with a convertible bucket attachment in accordance with the present invention, the attachment being illustrated in its bucket configuration; 
     FIG. 2 is an enlarged fragmentary right side elevational view showing the convertible bucket attachment elevated and swung forwardly into a dump position; 
     FIG. 3 is an enlarged, fragmentary side elevational view of the attachment showing the clam portion in a raised position to reveal the dozer blade; 
     FIG. 4 is an enlarged, left rear perspective view of the attachment in its bucket configuration showing the way in which the main operating components of the attachment are all mounted on the transverse foundational base of the attachment; 
     FIG. 5 is an enlarged, fragmentary top plan view of the attachment in the side-shifted angle dozer configuration with the clam raised and the dozer blade in an angled and side-shifted position to the right with respect to the direction of travel, parts being broken away to reveal details of construction; 
     FIG. 6 is an enlarged right side elevational view of the attachment in the bucket configuration and in partial section showing the dozer blade positioned as the back wall of the bucket; 
     FIG. 7 is a fragmentary horizontal cross-sectional view taken along line 7--7 of FIG. 2 of the right, rear corner of the attachment showing part of the lost-motion connection between the swing arm and the dozer blade at that location; and 
     FIG. 8 is a fragmentary left front perspective view of the attachment in the right, side-shift angle dozer configuration of FIG. 5. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring initially to FIGS. 1 and 2, a convertible bucket attachment 10 in accordance with the present invention is mounted to a front end loader 12 to be lifted and swung about a horizontal axis between loading and dumping positions as shown by a comparison of FIGS. 1 and 2. The front end loader 12 is mounted on the chassis 13 of a tractor 14 and includes a pair of forwardly extending, laterally spaced apart lift arms 16 and 18 (a portion of the latter being visible in FIG. 8). 
     In greater detail, and as perhaps shown best in FIGS. 4 and 8, the convertible bucket attachment 10 broadly includes three major components, i.e., a main transverse structural base 20 attached to the front ends of the loader arms 16,18, a clam 22 swingably attached to and carried by the base 20, and an angularly shiftable dozer blade 24 likewise mounted on the base 20, but independently of the clam 22. As shown in FIG. 8, the clam 22 includes a generally rectangular floor 28, a pair of triangular, spaced-apart, upright, substantially parallel side walls 30 and 32 joined along their lower edges to opposite lateral extremities of the floor 28, and a transverse structural beam 36 (FIG. 4) interconnecting the side walls 30,32 across their upper rear ends. The tubular beam 36 forms the main torsional backbone of the clam 22. The side walls 30 and 32 lie in substantially vertical, parallel planes, while the beam 36 is parallel to the transverse axis about which the clam 22 swings relative to the base 20. The aforesaid swing axis is defined by aligned hinge pins 38 and 40 (FIG. 4) which respectively connect rearwardly extending lugs 42 and 44 on the beam 36 to the upper ends of a pair of upright mounting brackets 46 and 48 fixed to the back side of the base 20. In this manner the clam 22 is swingably supported by and coupled with the base 20. 
     The floor 28 of the clam 22 is substantially planar and is provided with a front transverse scraping edge 50 extending between side walls 30 and 32. As illustrated in FIGS. 6 and 7, the floor 28 along its rear margin is upturned to present an upwardly and rearwardly projecting, transversely extending abutment flange 52 which is configured to engage and bear against a lower front scraping knife 54 on the dozer blade 24 when the clam 22 is in its lowered position as in FIG. 6. As shown in FIG. 8, three fore-and-aft skid plates 60, 62 and 64 are affixed to the bottom of floor 28 to strengthen the latter. As shown in FIGS. 3, 4 and 8, a pair of right and left, upright stiffening plates 66 and 68 are fixed to side walls 30,32 at their rear extremities, and fore-and-aft, downwardly inclined side cutter members 70,72 lead from the upper ends of the plates 66,68 to the lower front corners of the side walls 30,32. Gussets 34 provide additional strengthening between the side cutters 70,72 and floor 28. 
     The clam 22 is raised and lowered about pivot pins 38,40 by an upright double acting hydraulic cylinder 74 on the rear of the base 20 (FIGS. 3 and 4). A pair of side-by-side crank arms 76 and 78 extend normally rearwardly from beam 36 and have a pivot pin connection 80 with the head 82 of the extensible shaft 84 of the cylinder 74. The lower, anchor end of cylinder 74 is pivotally mounted to base 20 by pin 86. 
     The mounting base 20 is transversely generally U-shaped (FIGS. 4 and 8) in the nature of a wide structural channel member, presenting an upright flat bight 104 and a pair of upper and lower, longitudinal flanges 106,108 which project forwardly from bight 104. The clam mounting brackets 46,48 are fixed to the rear face of bight 104 and project upwardly beyond the upper flange 106 to provide operating clearance for the dozer blade 24 as will hereinafter be described in more detail. Upper holes 88 and lower holes 90 in the brackets 46,48 provide points of attachment of the base 20 to the loader 12. As shown in FIG. 2, for example, dump links 92 of the loader 12 are connected by pins 94 to holes 88, while lift arms 16,18 are connected by pins 96 to lower holes 90. A pair of upright, laterally spaced apart plates 100,102 are affixed to the back face of bight 104 centrally thereof to confine the hydraulic cylinder and to provide a mounting location for the cylinder mounting pin 86. 
     The dozer blade 24 is mounted on the base 20 by coupling means located on the front side of the base 20 and denoted broadly by the numeral 109 in FIGS. 4, 5, 6 and 8. In this regard it will be seen that the top flange 106 has a pair of mounting holes 110 and 112 adjacent the center of flange 106, while the lower flange 108 includes a pair of corresponding holes (not shown) positioned respectively therebeneath. Holes 110 and 112 receive, respectively, upright spindles 122 and 124, which serve to pivotally mount a pair of arms 126 and 128 of the mounting means 109 to the base 20. Suitable bearings 130 associated with the spindles 122,124 facilitate the horizontal swinging movement of the arms 126 and 128. 
     Swinging of the arms 126 and 128 when the clam 22 has first been raised is controlled and effected by power mechanism in the nature of a pair of double-acting hydraulic cylinders 142 and 150 which lie horizontally along the front face of the base 20. Each of the arms 126 and 128 is provided with a pair of mounts 132 and 134 which receive a normally vertically oriented pivot pin 136 therethrough that is spaced a short distance from the corresponding spindle 122 or 124. Pin 136 extends through the head 138 of the shaft 140 of the corresponding cylinder 142 or 150 such that the cylinders 142 and 150 are connected to their respective arms 126 and 128 with relatively short moment arms. 
     Each of the cylinders 142,150 is pivotally attached at its anchor end to the front face of the bight 104 by its own pair of vertically spaced mounting ears 114 and vertical pivot pin 120, located generally adjacent opposite ends of the base 20. The cylinders 142,150 are operable to swing the arms 126 and 128 between a folded-in position as illustrated by the arm 126 in FIGS. 5 and 8, and folded-out position as illustrated by the arm 128 in the same figures. Arms 126 and 128 are generally channel-shaped to present upper and lower flat edges 152 and 154 which are interconnected by a slightly concave main body portion 156 as shown in FIGS. 6 and 8. Such configuration provides structural strength as well as clearance for the transverse cylinders 142,150 when the arms 126,128 are folded in. 
     The outer ends of the arms 126,128 are coupled with opposite ends of the dozer blade 24 through a pair of lost-motion connections 155 and 157 respectively, as shown in FIGS. 5 and 8. The lost-motion connections 155,157 provide for side-shifting of the blade 24 in addition to its angle adjustment. As shown best in FIG. 8 (and also in FIG. 6), each of the lost motion connections 155,157 includes an upright guide rod 158 adjacent the outer end of the respective arm 126,128 which spans the opposite edges 152,154 and projects a short distance beyond each of edges 152,154. The opposite extended ends of each rod 158 are received within corresponding upper and lower guide slots 160 and 162 in a pair of vertically spaced, horizontal guide plates 164 and 166 on the back side of the dozer blade 24. The distance along the blade 24 between the outer ends of the slots 160 is substantially the same as the distance between the rods 158 when arms 126,128 are fully folded in. Thus, the blade 24 must also be retracted into a centered, squared-up position when the arms 126,128 are folded in. On the other hand, the distance between the inner ends of the slots 160 along the blade 24 is substantially the same as the distance between the rods 158 when one of the arms 126 or 128 is swung out and the other remains folded-in (as in FIGS. 5 and 8). Consequently, the blade 24 must also be held in either a right or left side-shifted, angled attitude at that time, depending upon which arm is folded in and which is swung out. 
     The dozer blade 24 itself is of generally box-like construction (FIGS. 4, 6 and 8) with a closed top 168, closed bottom 170, closed front 172, closed ends 174,176, but an open back. The front 172 is slightly concave, and the open nature of the back permits the base 20, arms 126,128 and the transverse cylinders 142,150 all to be nested neatly within the hollow blade 24 when the attachment 10 is in its bucket configuration as in FIGS. 4 and 6 for example. It will also be noted as shown in FIG. 4 that when the attachment 10 is in its bucket configuration, the stiffening side plates 66,68 of the clam 22 partially rearwardly overlap the opposite ends 174,176 of the dozer blade 24 to rigidify the bucket and preclude lateral displacement of the blade. Thus, the blade 24 is trapped front-to-rear at this time by the upturned flange 52 of clam 22 and the base 20, and side-to-side by the stiffening side plates 66 and 68. 
     One exemplary loader useful in connection with the present invention is a Bobcat 2400 Loader available from the Melroe Company of Fargo, North Dakota. As shown in FIGS. 1 and 2, in addition to the loader arms 16,18, the front end loader includes lift cylinders 184 for raising loader arms 16,18, and also tilt cylinders 186 mounted to the loader arms 16,18 and connected to links 92. Links 92 and tilt cylinders 186 are additionally connected to loader arms 16,18 by bail 188, as seen in FIG. 2. The front end loader 12 naturally includes a hydraulic pump (not shown) which is connected to the various hydraulic cylinders (all of which are double-acting) by conduits 190. Controls (not shown) are provided in the cab 192 of tractor 14 so the operator can not only operate the attachment 10 in the usual way from the tractor seat, but can also convert quickly between bucket and dozer configurations. 
     OPERATION 
     In use, the convertible bucket attachment 10 is mounted on the loader arms 16,18 in the manner illustrated in FIGS. 1 and 2 in lieu of conventional buckets or dozer blade assemblies. In the bucket configuration, the material which is resting on the ground or other supporting surface may be loaded into the bucket attachment 10 in the usual way by driving the vehicle forward and passing the scraping edge 50 of the bucket 10 under the material to be lifted. Lift cylinders 184 are then extended to raise the loader arms 16,18 and thereby raise the bucket 10 off the ground. 
     As with conventional buckets, the convertible bucket attachment 10 hereof may be tilted to drop the material collected therein at the desired location by extending tilt cylinder 186 to pivot bale 188. In so doing, the entire attachment 10 tilts, including base 20, clam 22 and dozer blade 24. 
     It is to be understood that by virtue of the present configuration, the load placed on floor 28 and also against scraping edge 50 will tend to swing the clam 22 in a clockwise direction viewing FIGS. 1 and 6 so that the flange 52 is forced rearwardly against knife 54 to hold the dozer blade 24 back against the base 20. The side walls 30 and 32 of clam 22 overlap opposite lateral ends of the dozer blade 24 whereby to confine the blade 24 and render it completely immobilized at this time. The result is a very rugged, sturdy bucket that can readily withstand the rigors of heavy-duty earth-working and material handling operations, even when the front edge of the bucket 10 is used to pry loose heavy stones and other objects. It will be noted in this respect that because the clam 22 is attached directly to the base 20 via the brackets 46,48 instead of to the dozer blade 24, there is no twisting moment applied to the dozer blade 24 when the front edge of the clam is subjected to a heavy load in this manner. Instead, the clam 22 simply tends to clamp the dozer blade 24 even more tightly against the base 20. 
     In order to prepare the dozer blade 24 for dozing operations, the clam 22 must first be swung into a raised position as illustrated in FIG. 3 to expose the dozer blade 24. This is accomplished by actuating double-acting hydraulic cylinder 74 to retract shaft 84 and thus bring head 82 down toward cylinder 74. Once the clam 22 is raised, the dozer blade 24 may be left in its centered, straight-forward position if desired and used to push materials straight ahead when the tractor is advanced. 
     On the other hand, once the clam 22 has been raised, the dozer blade 24 is also released for either right or left side-shifting and angle displacement if such is desired for the particular job at hand. In the illustration of FIGS. 5 and 8, for example, the dozer blade 24 has been shifted and angled to the right (as viewed from the rear of the machine), although it is to be understood that the blade 24 could just as easily have been shifted and angle-adjusted to the left. 
     Using the right angle shifted position of FIGS. 5 and 8 as an example, it will be understood that movement of the dozer blade 24 to that position is effected by operating the appropriate control in the tractor cab 192 to extend the swing cylinder 142 while keeping the other swing cylinder 150 fully retracted. Although not illustrated in the drawings, it is to be understood that the guide rods 158 of the lost motion connections 155,157 are at the outer ends of their guide slots 160 in the dozer blade 24 when the blade 24 is in its centered, straight-forward position of FIGS. 3, 4 and 6. Thus, when the cylinder 142 is initially extended and the swing arm 128 starts to swing outwadly away from its folded-in, transverse position toward its folded-out, longitudinal position of FIGS. 5 and 8, the guide rod 158 of lost motion connection 155 slides toward the inner end of the slot 160 until it can go no further. Further outward swinging of the swing arm 128 thus has the effect not only of pushing the left end of the dozer blade 24 outwardly, but also of displacing the blade 24 in a rightward direction along its own longitudinal axis until the rod 158 of the other lost motion connection 157 bottoms out at the inner end of its slot 160. Consequently, as shown most clearly in FIG. 5, even though the blade 24 started out fully within the lateral boundries defined by the opposite side walls 30 and 32 of the clam 22, in its final side-shifted and angle adjusted position the blade 24 has its right end projected laterally outwardly beyond the corresponding right side wall 30 of the clam 22. Once the cylinder 142 is fully extended, the operator may simply release the control valve or otherwise move it to a position which hydraulically locks the cylinder 142 in its extended state while the cylinder 150 is also locked in its retracted state, thus rigidly and securely holding the blade 24 in its side-shifted, angled position. 
     With the dozer blade 24 in this position, the vehicle is ideally suited for windrowing loose materials which are scattered on the ground, or for backfilling a ditch such as the ditch 194 illustrated in FIG. 5. By advancing alongside of the ditch 194 in the direction of forward travel &#34;T&#34; illustrated in FIG. 5 with the rightwardly projected end of the dozer blade 24 engaging the &#34;spoil&#34; pile 196 of loose soil which has been previously removed from the ditch, the dozer blade 24 simply diverts and rolls the spoil 196 smoothly and continuously into the ditch as the vehicle continues to advance. Because of the laterally projected condition of the dozer blade 24, the front wheel 180 of the tractor can be maintained at a safe distance from the sides of the ditch to guard against the risk of cave in. Moreover, with the right end of the dozer blade 24 shifted outboard of the right side wall 30 of the clam 22, the operator has an excellent view of the soil as it rolls into the ditch so that he may react quickly to any steering adjustments that may become necessary as the backfilling operation is carried out. 
     Having the dozer blade 24 side-shifted as well as angle-adjusted improves the steerability of the tractor 14 compared to that which would exist if the dozer blade 24 were only angle-adjustable and not also side-shiftable. This improvement would be particularly noticeable where light tractors were utilized and the spoil pile quite large. Without side-shift of the dozer blade 24, there would be a tendency for the reaction force from the spoil pile to swing the tractor out away from the ditch and make steering difficult; that tendency is decreased when the blade 24 is side-shifted. 
     When the operator wants to return to the bucket configuration, he merely needs to operate the appropriate control at the tractor seat to swing the dozer blade 24 back into its centered position and then lower the clam 22 back down into its original position against the dozer blade 24. Assuming for the sake of illustration that the dozer blade 24 is at the right shifted, angle adjusted position of FIGS. 5 and 8 prior to returning to the bucket configuration, the operator causes the swing cylinder 142 to retract and progressively swing the control arm 128 back to its folded-in position along the base 20. As the arm 128 swings in a counterclockwise direction viewing FIG. 5, the rod 158 of the lost motion connection 155 slides to the outer end of slot 160 such that further inward swinging of the arm 128 has the effect of pulling the dozer blade 24 laterally inwardly at the same time it is being swung back toward the squared up position. Such pulling action by the inwardly swinging arm 128 on the left end of the dozer blade 24 also causes the rod 158 of lost motion assembly 157 at the right end of the blade 24 to slide to the outer end of its slot 160 until rod 158 can go no further. By the time the dozer blade 24 has been fully returned to its centered, squared up position, the cylinder 142 will be fully retracted and both of the rods 158 will have been shifted to the outermost ends of their respective guide slots 160. Extension of the clam cylinder 74 then lowers the clam 22 into clamping position against the dozer blade 24 to reestablish the loading bucket configuration. 
     It is to be appreciated that converting the attachment of the present invention between bucket and dozer configurations can be carried out virtually instantaneously from the tractor seat without disconnecting and interchanging heavy components. Thus, the operator has full use of an excellent loading bucket for all of the many jobs which require that kind of a loading implement while having instant access to a straight dozer blade or a right or left shifted, obliquely angled dozer blade for the times backfilling or cleanup is required. Even though the dozer blade may only be needed for relatively brief intervals throughout the day, the operator can quickly and easily shift back and forth between bucket and dozing modes at will to provide safe, efficient and high quality work in the least amount of time. By using the clam 22 in swingable cooperation with the front face of the dozer blade 24, the operator can also use the attachment for picking up and transporting bulky objects such as logs and large stones. 
     Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention. 
     The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.