Digging tooth

Abstract: A digging tooth (12) for a backhoe bucket (10) has a concave top surface (20) and a convex bottom surface (22) which intersect forming a forward cutting edge (28). Side­ walls (24, 26) connect the two surfaces (20, 22) and are concave having a moldboard shape. The rear portion of the tooth (12) is provided with mounting means (16, 18) for mounting it on the bucket (10). The bottom surface (22) continuously diverges from the forward cutting edge (28) to the rear portion (29), whereas the top surface (20) first converges then diverges from the forward cutting edge (28) to the rear portion.

Description: This invention relates to a digging tooth for a digging bucket comprising: a wedge shaped body having a rear portion including an upper edge, a lower edge vertically spaced to the upper edge and two laterally spaced side edges interconnecting the upper and lower edges, and tapering to a forward cutting portion; a first surface representing an upper top surface, extending and being concave (as viewed from the side) between the upper edge of the rear portion and the cutting portion and being provided with two laterally spaced concave (as viewed from the top) top side edges: a second surface representing a lower bottom surface opposite to the first surface, extending and being at least partially rounded (as viewed from the side) between the lower edge of the rear portion and the cutting portion and being provided with two laterally spaced concave (as viewed from the bottom) bottom side edges which (as viewed from the bottom) first converge than diverge when proceeding from the forward cutting portion to the rear portion; a forward cutting edge on the forward cutting portion formed by the upper top surface and the lower bottom surface intersecting each other; two side walls extending between the side edges of the rear portion and the cutting portion and having concave upper and lower side edges congruent to said concave top side and bottom side edges; and means for mounting the rear portion of the tooth to the bucket. Modern backhoes and excavators are designed to move a bucket through an arcuate path when digging. In addition, the cutting angle of the bucket can be adjusted by manipulating a bucket hydraulic cylinder during the digging operation. Bucket teeth may be added to the bucket to aid in this operation. Traditionally digging teeth have a wedge shaped configuration. However, over the years many different configurations of digging teeth have been proposed. US-A-4 642 920 which is considered in the opening paragraph discloses digging teeth having a wedge-shaped configuration and concave sidewalls. US-A-4 321 762 discloses digging teeth having sloped sidewalls. US-A-4 123 861 discloses mounting means with a cavity located in the rear portion of the tooth. FR-A-2 596 785 discloses a digging tooth with a lower bottom surface which is partially convex. It is an object of the present invention to provide a digging tooth configuration that more easily moves through material thereby increasing the efficiency or cutting ability of the digging bucket to which it is attached. According to the present invention the lower bottom surface is continuously convex (as viewed from the side) between the lower edge of the rear portion and the cutting portion, the two top side edges of the upper top surface (as viewed from the top) continuously diverge when proceeding from the forward cutting edge to the rear portion, the side walls diverge from said lower side edge to said upper side edge (as viewed from the bottom), and the mounting means include a cavity located in the body, open to the rear portion and shaped for receiving a bucket mounted shank such that upon attachment to the bucket the convex lower bottom surface is substantially tangential to the bottom surface of the bucket. An embodiment of the invention will now be described with reference to the accompanying diagrammatic drawings in which: Fig. 1 is a side view of a digging bucket provided with the digging teeth; Fig. 2 is a top view of the digging tooth; Fig. 3 is a front view of the digging tooth; Fig. 4 is a side view of the digging tooth; and Fig. 5 is a bottom view of the digging tooth. Excavator or backhoe bucket 10, illustrated in Figure 1, is provided with a plurality of cutting teeth 12. Bucket 10 is operatively secured to an excavator by linkage 14, only a portion of which is shown. Cutting teeth 12 are secured to the bucket in a conventional manner. A mounting shank 15 is secured to the forward edge of the bucket and is provided with mounting apertures 16. The cutting tooth is provided with aligned mounting apertures 16 located in both sidewalls of the tooth. The tooth is also provided with a shank receiving cavity 18 located at the rear of the tooth. In mounting the tooth on the bucket, the tooth is placed over the mounting shank projecting from the bucket and flex pin 17 is inserted through apertures 16 and the aligned apertures in the shank, thereby securing the tooth to the bucket. The bucket tooth is best illustrated in Figures 2-5. The tooth is provided with a concave top surface 20, a convex bottom surface 22 and two concave sidewalls 24 and 26. The top and bottom surface intersect to form forward cutting edge 28. The rear portion of the tooth is provided with mounting means for mounting the tooth on the bucket. The mounting means comprises mounting aperture 16 and shank receiving cavity 18. The convex bottom surface of the digging tooth approximately conforms to the digging arc of the bucket. As illustrated in Figure 1, the convex bottom surface is substantially tangential to the bottom surface of the bucket. By having this convex surface, the digging tooth is not fighting itself during a digging operation. Bottom surface 22 is also hour-glass shaped as defined by bottom-side edges 30 and 32 formed by bottom surface 22 with sidewalls 24 and 26, respectively. Proceeding from the forward cutting edge to the rear portion of the digging tooth, the bottom surface first converges then diverges creating the hour-glass shape. The concave top surface provides digging relief as it allows material to roll into the hollow formed by the concave surface rather than be compressed by a flat surface. The top surface is also wedge shaped as defined by top-side edges 34 and 36 formed by top surface 20 with sidewalls 24 and 26, respectively. The top surface continuously expands from the forward cutting edge to the rear portion of the tooth. The top portion is also provided with flat surface 38 which forms a wear area for cutting edge 28. Sidewalls 24 and 26 are moldboard-shaped defining concave surfaces. The sidewalls are flattened surrounding aperture 16 to facilitate mounting the tooth on the bucket.

Claims: A digging tooth (12) for a digging bucket (10) comprising: a wedge shaped body having a rear portion including an upper edge, a lower edge vertically spaced to the upper edge and two laterally spaced side edges interconnecting the upper and lower edges, and tapering to a forward cutting portion; a first surface representing an upper top surface (20), extending and being concave (as viewed from the side) between the upper edge of the rear portion and the cutting portion and being provided with two laterally spaced concave (as viewed from the top) top side edges (34, 36): a second surface representing a lower bottom surface (22) opposite to the first surface, extending and being at least partially rounded (as viewed from the side) between the lower edge of the rear portion and the cutting portion and being provided with two laterally spaced concave (as viewed from the bottom) bottom side edges (30, 32) which (as viewed from the bottom) first converge than diverge when proceeding from the forward cutting portion to the rear portion; a forward cutting edge (28) on the forward cutting portion formed by the upper top surface (20) and the lower bottom surface (22) intersecting each other; two side walls (24, 26) extending between the side edges of the rear portion and the cutting portion and having concave upper and lower side edges congruent to said concave top side and bottom side edges (30, 31, 34, 36); and means (16, 18) for mounting the rear portion of the tooth (12) to the bucket (10), characterised in : the lower bottom surface (22) being continuously convex (as viewed from the side) between the lower edge of the rear portion and the cutting portion; the two top side edges (34, 36) of the upper top surface (22) (as viewed from the top) continuously diverge when proceeding from the forward cutting edge (28) to the rear portion; the side walls (24, 26) diverge from said lower side edge to said upper side edge (as viewed from the bottom) ; and the mounting means (16, 18) include a cavity (18) located in the body, open to the rear portion and shaped for receiving a bucket mounted shank such that upon attachment to the bucket (10) the convex lower bottom surface (22) is substantially tangential to the bottom surface of the bucket (10).

Inventors: FELLNER RONALD W, FELLNER, RONALD W.
Applicants: DEERE & CO, DEERE & COMPANY
Application year: 1990
Main classification: E02F3
IPC codes: E02F9