Excavating Buckets

This invention relates to excavating buckets.

Excavating buckets, such as those used on apparatus commonly known as a backhoe, are usually pivotally attached to a movable dipperstick, with separate actuators arranged to power bucket pivoting and dipperstick movements, respectively. Such buckets often have teeth-like protrusions along a leading edge which loosen and scoop material as the bucket moves through the substrate to be excavated; and may also include a row of ripper teeth attached to the rear of the bucket (i.e., on the side opposite the leading edge) generally parallel to the leading edge and perpendicular to the direction of the motion of the bucket for dislodging and breaking up tightly compacted substrate. Such ripper teeth are usually arranged to operate with the bucket actuator fixed in a fully extended position, and the ripping motion is powered by the dipperstick actuator.

Such ripper teeth have not been entirely satisfactory. They often penetrate too deeply and tend to "stall out" the dipperstick cylinder. Additionally, the material loosened has a tendency to jam the motion of the bucket and cause it to ride over the material and thus reduce ripping penetration; and efficiency of operation is hindered by the need constantly to reposition the bucket to maintain the proper ripper tooth cutting angle.

It is an object of the present invention to maximize ripping effectiveness while at the same time overcoming the above limitations.

I have discovered that, by providing a plurality of rippers which protrude downwardly from the bottom (either V-shaped or flat) of an excavating bucket and face towards its front edge, the rippers being staggered from the front edge to the back of the bucket at varying distances from the bucket sides, powered movement of the bucket through a substrate will dislodge pieces without generating drag to stall the bucket's movement. The rippers can be permanently fixed to the bucket bottom or can be part of an adapter which itself may be attached to a bucket.

In preferred embodiments the rippers are not aligned with each other either transversely or longitudinally of the bucket, but are spaced front to rear in a V-pattern. The forward edges of the rippers may all lie on a constant radius measured from the axis of pivotal connection of the bucket to the dipperstick (or, as may sometimes be preferred or from a point above or below the axis of pivotal connector), or may lie on an elliptical arc tailing in towards or away from the bucket bottom. The lead ripper may be positioned either on or behind the bucket front edge; the ripper pattern may be such that each ripper fractures material into the grooves cut by the preceding ripper; all rippers are designed to maintain the optimum cutting angle (generally 35.degree.-55.degree. and, preferably, 45.degree.); and for any ripper the clearance between its teeth and the bottom of bucket is greater than in the case of the rippers forward of it.

We turn now to the preferred embodiments of the invention, first briefly describing the drawings.

FIG. 1 is a side elevation of the bucket, partly broken away.

FIG. 2 is a bottom view of the bucket of FIG. 1.

FIG. 3 is a side elevation of a bucket and attachment therefore, showing another embodiment of the invention.

FIGS. 4 and 5 are detailed views of a ripper used in either of the embodiments of FIG. 1 or FIG. 3.

FIG. 6 is a side elevation of the bucket of FIG. 1, showing variations in ripper radius.

FIG. 7 is a side elevation of a V-bottom bucket embodying the invention.

FIGS. 8A and 8B are schematics showing ripper placement.

As shown in FIGS. 1 and 2, backhoe bucket 30 is attached to dipperstick 22 with hinge pin 32 and to link member 24 with hinge pin 34. Piston rod 26 connects hydraulic actuator 28 to link member 24, and link 50 connects member 24 and dipperstick 22. Leading or scooping edge 36 of bucket 30 has five forwardly disposed teeth 38, extending from forward-pointing, "V"-shaped cutting plate 40.

Bucket 30 has curved bottom plate 42, connecting two side walls 45 and 49 and forming both the bottom 44 and back 46 of the bucket, and a top plate 48. Seven rippers 52 are attached to bottom plate 42, staggered at regular intervals from bucket scooping edge 36 to the rear of plate 42. The forward six of ripper 52 are arranged in a V-configuration, with the center one of teeth 38 on edge 36 forming the apex of the V, and the rippers 52 at the rear of the V close to the bucket sides. The rear most ripper 52 is not part of the V, but is aligned with center tooth 38. As shown in FIG. 2, no two rippers 52 are aligned with each other, either from side-to-side or from front to back of bucket 30. Also, as shown in FIG. 1, the clearance between each ripper 52 and the bottom 44 of the bucket progressively increases from front to rear of the bucket.

Referring now to FIGS. 4 and 5, each ripper 52 includes a shank 56 fixed to the bucket bottom 44, and a ripper tooth 54 fitted over the end of the shank and held in place by a pin 60.

Each tooth 54 includes relatively inclined upper and lower surfaces, 62, 64 respectively, which set in a point 66 at the front of the tooth. The points 66 of all of rippers 52 are equidistant from the hinge pin 32 about which bucket 30 rotates relative to dipperstick 22, as illustrated by arc A of radius R. As shown, the center one of teeth 38 also lies on arc A. The upper surface 62 of each tooth 54 defines the tooth cutting angle, a, which, for each of rippers 52, is between about 35.degree. and 55.degree. and, preferably, 45.degree.. The lower surface 64 is positioned so that it will not bottom-out in the trench cut by the tooth as the bucket is pivoted about hinge pin 32. The progressively greater clearance (front to rear) between the ripper and bucket bottom 42 is provided by, as shown, a progressive increase in the length of shanks 56.

FIG. 3 shows an alternative embodiment of the invention in which plate 47' is welded or bolted to the bottom digging surface 44' of bucket 30'. Rippers 52' are attached to plate 47' and are identical to the rippers 52 of bucket 30. Depending on the curvature of surface 44' of a particular bucket, the arc corresponding to A may not necessarily have a constant radius; however, the arrangement of progressively longer shanks and staggering of teeth with respect to edge 36 and the bucket sidewalls remains the same.

FIG. 6 illustrates the effect of mounting rippers 52 on a constant radius measured from a point that is above (P.sub.1) or below (P.sub.2), rather than coincident with, hinge pin 32. As shown, mounting the rippers on a constant radius R.sub.1, measured from P.sub.1 causes the arc A, on which the teeth 54, lie to tail in towards the bucket bottom 46 so that, as bucket 30 is rolled about hinge pin 32, the rippers pull away from the ground. With rippers so mounted, an operator would drop boom 22 as the bucket is rolled to maintain contact between the rippers and the ground.

Similarly, mounting the rippers on a constant radius R.sub.2 measured from P.sub.2 causes the arc A.sub.2 on which teeth 54.sub.2 lie to tail away from the bucket bottom 44, and the rippers will engage the ground more aggressively as bucket 30 is rolled about hinge pin 32.

FIG. 7 shows a bucket 30" having a V-shaped bottom 44". Rippers 52" are attached to bottom 44" and are identical to the rippers 52 of bucket 30. Viewed from the side, the arc A.sub.3 on which the points 54" of rippers 52" lie elliptical and, like arc A.sub.1 of FIG. 6, tails in towards the bucket bottom. If desired, the rippers may also be positioned so that teeth 54" lie on an elliptical arc A.sub.4 which, like arc A.sub.2 of FIG. 6, tails away from the bucket bottom. Such elliptical arcs may be provided on either V-bottom buckets (as shown) or on flat-bottom buckets such as those shown in FIGS. 1 and 6.

Referring now to FIGS. 2 and 8-B, the center tooth 38 and rippers 52.sub.a -52.sub.f forming the "V" configuration earlier referred to are of such width and are so placed that, as bucket 30 is rolled, successive teeth fracture substrate into the groove cut by preceding teeth and leave a cut having flat continuous bottom.

Teeth such as those provided on the V-bottom bucket of FIG. 7 may similarly be mounted, as shown in FIG. 8-A, so that each trailing tooth fractures substrate into the groove cut by a preceeding tooth and the teeth forming the "V" configuration (as shown the center leading edge tooth 38" and six following rippers 52") makes cuts extending substantially continuously the bucket width.

Actuator 28 (the bucket cylinder) pivots the bucket about hinge pin 32 (the bucket's axis of attachment to dipperstick 22) causing the bucket to scoop loose substate with the scooping edge and teeth and to rip compact substrate with the rippers 52. It is also possible to rip by moving dipperstick 22, but much greater force is generally available from extending the bucket cylinder.

Because rippers 52 are not transversely aligned, they sequentially engage the substrate, permitting each tooth to provide the maximum digging force. The side-to-side staggering of the rippers prevents rocks, frozen earth, etc. from being trapped between adjacent teeth, and the progressively increasing clearance between the rippers and the bucket bottom provides room for material loosened by forward teeth to pass between more rearward teeth and the bucket bottom without forcing the bucket up off the substrate which would disengage the more rearward teeth. The preferred "V" configuration (front-to-rear) ripper pattern allows a trailing tooth to fracture the substrate into the groove already cut by a preceding tooth. As shown in FIGS. 2, 7 and 8-A and 8-B, the center lead tooth 38, 38" in the "V" makes the initial cut, ripper 52.sub.a, 52".sub.a fractures material from one side into the groove cut by tooth 38, 38", ripper 52.sub.b, 52".sub.b, fractures material from the other side into the groove cut by tooth 38, 38" ripper 52.sub.c, 52".sub.c fractures material from the first side into the groove cut by tooth 52.sub.a, 52".sub.a and so forth. The width and placement of the center tooth 38 and the rippers 52 are such that, as shown in FIGS. 8-A and 8-B, the successive grooves they cut will essentially abut and span the entire bucket width. As the bucket 30 is pivoted about hinge pin 32, each tooth cuts at the optimum cutting angle, without requiring adjustment or change in the position of the dipperstick.

The sequential ripping of teeth 54 is at controlled depths, and since all teeth are on a constant radius from the pivot point, the flat bottom buckets of FIGS. 1, 2 and 6 cut a flat-bottom trench automatically.

In other embodiments the rippers can be arranged in staggered patterns, i.e., patterns in which they do not align transversely or longitudinally, other than the front-to-rear "V"; the rippers may be bolted in place; the front edge of the bucket can be straight rather than "V" shaped; the teeth on the front edge can have other configurations such as flat or bifuracted; or, the front edge may be straight cutting edge and the leading ripper may lie behind the front edge and be mounted on the bucket bottom.

In still further embodiments, as noted with respect to FIG. 3, the radius on which the teeth are mounted may increase or decrease from front to rear of the bucket rather than remaining constant.

These and other embodiments will be within the scope of the following claims.