Abstract:
A material handling attachment such as a bucket or the like is pivotally secured to the three-point hitch assembly of the tractor. The hitch assembly is movable between a lower position and an upper position by means of standard equipment on the tractor, A mechanical linkage interconnects the bucket, hitch assembly and the tractor so that the bucket will be in a substantially level position when the hitch assembly is in its lowermost position. As the hitch assembly is moved upwardly relative to the tractor, the linkage maintains the bucket in a level position. When the hitch assembly reaches its uppermost position, the linkage causes the bucket to be moved to a dumping position. After the material in the bucket has been dumped therefrom, the three-point hitch assembly is lowered with the bucket being automatically re-set to its operative or working position.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part application of Ser. No. 814,043 filed Dec. 27, 1985. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a material handling attachment for a tractor and more particularly to a material handling attachment for a tractor having a three-point hitch assembly. 
     Many types of tractor loaders or front-end loaders for tractors have been previously provided. Conventional tractor loaders normally include a frame assembly secured to the tractor frame with a pair of hydraulically controlled boom arms pivotally secured to the tractor frame. A bucket, forklift, etc. is normally attached to the forward ends of the boom arms and is also hydraulically controlled. The conventional tractor loaders are normally quite large and are expensive. 
     Many of the tractors available today have what is known as the three-point hitch assembly secured to the rearward end thereof. The three-point hitch assemblies normally include an upper arm and a pair of lower arms with either the upper arm or the pair of lower arms being connected to some sort of internal mechanism such as a hydraulic cylinder or the like to cause the hitch assembly to be vertically moved with respect to the tractor. The three-point hitch assemblies normally accommodate implements such as blades, disks, plows, etc. Attempts have been made in the past to mount material handling equipment such as a loader bucket or forklift to the three-point hitch assemblies but is believed that all of the previous attempts have utilized hydraulic cylinders pivotally connected to the buckets or forklifts to cause the pivotal movement of the material handling equipment relative to the three-point hitch assembly or some type of manual tripping mechanism. The utilization of a hydraulic cylinder results in the need for quick couplers, hydraulic hoses, etc. in addition to the hydraulic cylinder itself. The addition of the couplers, hoses and cylinder adds considerably expense to the equipment and frequently results in oil leaks occurring. Additional controls are also required to cause the pivotal movement of the material handling equipment relative to the three-point hitch assembly. In the manual tripping type buckets, the same requires the operator to do so physically or manually, which is time-consuming and frequently difficult to perform. 
     Another disadvantage of the prior art devices is that the interior of the buckets are not protrusion free. Yet another disadvantage of the prior art is that the buckets must be constructed of extremely heavy material to enable the buckets to perform their desired function without the buckets being damaged. Yet another disadvantage of some of the prior art is some types of construction require that the pivot arms for the bucket be positioned outwardly of the sides of the bucket which necessarily creates a width restriction. 
     It is therefore a principal object of the invention to provide a material handling attachment for a tractor having a three-point hitch assembly. 
     A further object of the invention is to provide a material handling attachment for a tractor which includes self-leveling and automatic dumping features. 
     Still another object of the invention is to provide a material handling attachment for a three-point hitch assembly which does not require the need for additional couplers, hoses, cylinder, valves, etc. 
     Still another object of the invention is to provide a material handling attachment for a tractor which has an improved cycle speed. 
     Yet another object of the invention is to provide a material handling attachment for a tractor which has an automatic re-set feature after the bucket has been automatically moved to its dumping position. 
     Still another object of the invention is to provide a material handling attachment for a tractor which utilizes only one control lever, namely, the control lever for the three-point hitch assembly. 
     Still another object of the invention is to provide a material handling attachment for a tractor which is easily and quickly mounted on the three-point hitch assembly and quickly and easily removed therefrom. 
     Yet another object of the invention is to provide a material handling attachment for a tractor having less loader frame weight than in conventional devices since a hydraulic cylinder is not needed to pivotally move the loader bucket relative to the three-point hitch. 
     Yet another object of the invention is to provide a material handling bucket which is constructed of relatively lightweight material but which is extremely durable since a pair of support arms are pivoted directly to the forward end of the cutting blade positioned on the rearward end of the bucket. 
     Still another object of the invention is to provide a material handling attachment for a tractor which has high-lift capabilities. 
     Still another object of the invention is to provide a bucket of the type described which has the interior thereof protrusion free. 
     Yet another object of the invention is to provide a bucket of the type described wherein the pushing forces are applied directly to the cutting blade rather than on the bucket shell. 
     Still another object of the invention is to provide a device of the type described which is economical of manufacture and durable in use. 
     These and other objects will be apparent to those skilled in the art. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front exploded perspective view of the attachment of this invention: 
     FIG. 2 is a side elevational view of the attachment of this invention mounted on a tractor illustrating the attachment in its lowermost position: 
     FIG. 3 is a view similar to FIG. 2 except that the attachment has been moved upwardly from the position of FIG. 2 and has been moved to its dumping position: 
     FIG. 4 is a side view of the loader bucket of this invention mounted on a tractor: 
     FIG. 5 is a view similar to FIG. 4 except that the loader bucket has been moved upwardly from the ground: 
     FIG. 6 is a view similar to FIGS. 4 and 5 except that the bucket has been moved upwardly from the position of FIG. 5 and illustrating the manner in which the bucket is maintained in a level condition as it is being vertically moved: 
     FIG. 7 is a view similar to FIGS. 4-6 except that the bucket has been vertically moved upwardly: 
     FIG. 8 is a view similar to FIGS. 4-7 except that the bucket is shown as it begins to dump: 
     FIG. 9 is a view similar to FIGS. 4-8 but which illustrates the bucket in its dumping position: 
     FIG. 10 is a partial side view of the forward end of the bucket: 
     FIG. 11 is a sectional view of the blade positioned at the forward end of the bucket illustrating the manner in which the support arms are pivotally connected thereto. 
    
    
     SUMMARY OF THE INVENTION 
     A material handling attachment such a bucket or the like is pivotally secured a three-point hitch assembly of a tractor. The hitch assembly is vertically movable between a lower position and a upper position by means of the standard equipment on the tractor. A mechanical linkage means interconnects the bucket, hitch assembly and the tractor in such a manner so that when the three-point hitch assembly is in its lower position, the bucket will be in a substantially level position. As the three-point hitch assembly is moved upwardly relative to the tractor, the linkage means maintains the bucket in a substantially level position. When the three-point hitch assembly reaches its upper position, the linkage means causes the bucket to be moved to a dumping position. After the material in the bucket has been dumped therefrom, the bucket may be lowered to bring the blade of the bucket into ground engagement so that the bucket may be used as a scraper or leveling device. The construction of the bucket is of relatively lightweight material which is made possible by the fact that a pair of the support arms for the bucket are pivotally secured directly to the forward end of the cutting blade of the bucket. 
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Although the material handling attachment described herein is preferably a loader bucket, other attachments could be substituted therefor such as a forklift or the like. Additionally, the three-point hitch assembly is described herein as being located on the rearward end of the tractor as is the general rule, it should be understood that the hitch assembly could also be mounted on the front end of the tractor. 
     The numeral 10 refers to a conventional tractor which has a vertically movable three-point hitch assembly 12 at either its forward or rearward end and which is commonly referred to as a multiple-point or three-point hitch. The bucket assembly of this invention is designated by the reference numeral 14 and is designed to be secured to the three-point hitch assembly of the conventional tractor whether the three-point hitch assembly is mounted on the rearward or forward ends of the tractor. Whether the hitch assembly is mounted on the forward or the rearward end of the tractor, the three-point hitch assembly will normally include a pair of lower link arms 16 and 18 and an upper link arm 20. The conventional tractor 10 includes means for vertically moving the hitch assembly in conventional fashion. 
     Bucket assembly 14 includes a horizontally disposed support 22 which has brackets 24 and 26 positioned at its opposite ends respectively. Brackets 24 and 26 are pivotally connected to the ends of link arms 16 and 18 by pins 28 and 30 respectively. Upstanding post 32 is secured to support 22 and has a shaft or rod 34 rotatably mounted thereon which extends laterally from both sides thereof. Shaft 34 is rotatably received in brackets 24 and 26 and has lever arms or links 36 and 38 connected to its ends for rotation therewith. 
     As seen in the drawings, arm 36 has a plurality of openings 40 formed therein while arm 38 has a plurality of openings 42 formed therein. One end of link 44 is pivotally received in one of the openings 40 in arm 36 and one end of link 46 is pivotally received by one of the openings 42 in arm 38. The other ends of links 44 and 46 are pivotally secured to brackets 48 and 50 which are secured to bucket 52. A pair of spaced-apart support arms 54 and 55 are secured at their forward ends to support 22 in a horizontally spaced-apart condition by welding or the like and extend first downwardly and rearwardly therefrom and thence rearwardly therefrom as illustrated in FIG. 1. The rearward ends of arms 54 and 55 are pivotally secured to the forward ends of blade 57 by removable pins 56 as will be described in more detail hereinafter. 
     Cam 58 is secured to shaft 34 within post 32 for rotation with shaft 34. One end of chain 60 is secured to the upper end of cam 58 as seen in the drawings. The other end of chain 60 is secured to the tractor drawbar 62 or some other portion of the tractor as will be described in more detail hereinafter. Spring 64 is secured at its upper end to post 34 and is secured at its lower end to cam 58 for yieldably resisting the downward pivotal movement of cam 58. 
     For purposes of description, bucket 52 will be described as including a bottom portion 66 which is substantially horizontally disposed when the hitch assembly of the tractor is in its lowermost position as illustrated in FIG. 2. Bucket 52 also includes side walls 67 and 69 having back wall portions 68 and 70 extending therebetween. An elongated substantially flat cutting blade 57 is provided at the forward end of the bucket and extends thereacross as illustrated in the drawings. Blade 57 includes a tapered portion 73 at its rearward end and a sharpened tip portion 75 as seen in the drawings. The rearward end of bottom portion 66 of bucket 52 is positioned on the blade 57 as illustrated in FIG. 10 and has its rearward end bent downwardly and rearwardly so as to conform to the tapered portion 73 of blade 57. Bottom portion 66 is welded to blade 57. A pair of spaced-apart collars 77, 79 and 77&#39;,79&#39; are welded to the forward end of blade 57 and receive the pins 56 to effect the pivotal connection between the support arms 54 and 55 to the blade 57. 
     In FIG. 4, the bucket 52 is illustrated in its lowermost position as is the three-point hitch assembly 12. When it is desired to move dirt or the like, the bucket 52 may be positioned as in FIG. 4 or any position thereabove such as illustrated in FIGS. 5, 6 or 7. The tractor is backed so that the bucket 52 is filled with the material to be transported. It can be seen that the relationship of the support arms 54 and 55 with respect to the blade 57 makes it possible to construct the bucket 52, except for the blade 57, of relatively lightweight material since the rearward ends of the support arms 54 and 55 push directly against the forward end of the blade 57 so that objectionable forces are not applied to the bottom portion 66 or the side walls. It is also recommended that a pair of reinforcing members 81 and 83 be welded at the outer ends of the blade 57 and the rearward ends of the side walls of the bucket for additional strength. When the bucket has been filled, the tractor is driven to the location where the material is to be dumped or deposited. Continued vertical movement of the hitch assembly 12 from the position of FIG. 4 causes the bottom of the bucket to substantially remain level as illustrated in FIGS. 4-7. The bucket is pivoted in a clockwise direction relative to the hitch assembly 12 as the hitch assembly 12 is vertically moved upwardly from the position of FIG. 4 to the position of FIG. 5. The clockwise rotation or pivotal movement of the bucket 52 is caused by the chain 60 causing cam 58 to rotate as the hitch assembly is moved upwardly relative to the ground. Rotation of the cam 58 causes the rearward ends of the arms 36 and 38 to be moved upwardly which in turn causes the links 44 and 46 to pivot the bucket 52 in a clockwise direction. The relationship of the arms 36, 38 and the links 44 and 46 with respect to the brackets 48 and 50 prevents the bucket from dumping until the links 44 and 46 have moved from their &#34;off-center&#34; position of FIGS. 4-8. When the links 44 and 46 reach the position of FIG. 9, the bucket 52 is in the dumping position and is in effect powered into the dumping position by the relationship of the arms 36 and 38 and the links 44 and 46 without any action being required on the part of the operator. 
     When the material in the bucket has been dumped therefrom, the tractor operator may lower the hitch assembly 12, as desired. As the hitch assembly 12 is initially lowered, spring 44 tends to cause cam 58 to being to return to its original position. The operator may also lower the bucket until the blade 57 is into ground engagement and then drive the tractor forwardly while lowering the bucket so that the bucket 52 is moved to its working position. If the operator desires to utilize the bucket as a leveler or scraper, the bucket is simply lowered from the position of FIG. 9 until the blade 57 is in ground engagement. The operator may then drive the tractor rearwardly so that the blade 57 acts as a scraper blade. 
     The attachment of this invention enables a bucket or the like to be mounted on a conventional three-point hitch assembly of a tractor without the requirement of additional couplers, valves, hoses, or hydraulic cylinder being required. The attachment is quickly and easily removed from the tractor by simply removing three pins. When the bucket is positioned on the rearward end of the tractor, the weight of the material in the bucket provides additional traction to the tractor especially those tractors with two-wheel, rear drive. 
     Thus it can be seen that a novel attachment has been described for use with a three-point hitch of a tractor which permits the operation of the attachment to be controlled by the control which is used to control the three-point hitch of the tractor. The attachment may be cycled quickly since the operator will not be required to operate an additional hydraulic cylinder which is normally required on conventional arrangements. The instant invention not only provides a relatively inexpensive means for securing a loader bucket or the like to a hitch assembly of a tractor but it also provides an assembly which may be easily and quickly mounted on the tractor or removed therefrom. The elimination of the costly hydraulic cylinder for controlling the pivotal movement of the bucket is very important. In addition, the elimination of a hydraulic cylinder for pivoting the bucket also results in that a recess is not required in the back wall of the bucket which is needed in conventional devices of the general type described due to the fact that space must be provided for accommodating the hydraulic cylinder causing the open portion of the bucket to be divided into two chambers. 
     It can also be seen that a novel bucket construction has been provided which enables the bucket to be constructed of relatively lightweight material, except for the blade, since the support arms 54 and 55 are directly pivotally connected to the forward end of the blade 57 rather than to the side walls, back or bottom portions of the bucket. The fact that the bucket may be constructed of relatively lightweight materials not only decreases the cost of the bucket but enables the assembly to be shipped at a lower cost. The construction of the invention enables the same to be quickly and easily disassembled for shipment by UPS or the like. The construction of the bucket also provides a bucket which has its interior protrusion free. 
     Another feature of the invention described herein is that the supporting structure for the bucket enables the bucket to be positioned closely adjacent the rear of the tractor while yet obtaining a high-lift capacity. 
     Thus it can be seen that the invention accomplishes at least all of its stated objectives.