Backhoe bucket

The invention relates to a digging bucket for a backhoe or similar excavating machine, wherein the effective forward digging edge of the bucket may selectively comprise a transverse row of digging teeth for use in the primary phases of an excavation or a blade-type edge used for smoothing the bottom of the excavation. The backhoe bucket structure permitting this instantaneous choice by the operator comprises a conventional bucket having digging teeth secured thereto to the forward edge of the bottom but the medial portion of the bottom of the bucket is movably mounted relative to the remainder of the bucket so that the forward edge of the movable bottom portion can be dropped to a position below the digging teeth to function as a smoothing blade.

BACKGROUND OF THE INVENTION 
A backhoe is probably the most widely used implement at the current time 
for excavating basements, foundations, or trenches. As is well known, the 
digging efficiency of such backhoe, particularly in tight or stony soils, 
is greatly improved by utilizing a row of relatively sharp digging teeth 
spaced across the forward edge of the backhoe bucket. While such digging 
teeth are effective in the initial phases of the digging operation, they 
cannot be utilized when it is desired to produce a smooth planar surface 
on the bottom of the excavation. 
With prior backhoe constructions, it was necessary to remove the digging 
teeth and substitute a digging blade for such teeth, which is a 
time-consuming and hence, expensive operation. 
OBJECTS OF THE INVENTION 
It is accordingly an object of this invention to provide a digging bucket 
for a backhoe or similar excavating machine wherein the digging edge of 
the bucket may, at the desire of the operator, be immediately converted 
from a row of transversely spaced digging teeth to a blade or edge 
configuration. 
A particular object of this invention is to provide an improved backhoe 
bucket of conventional configuration with a plurality of digging teeth 
rigidly secured to the foreward edge of such bucket, but with a medial 
portion of the bottom of the bucket movably mounted relative to the 
remainder of the bucket so that the leading edge of said movable bottom 
portion may be dropped to a position below the digging teeth and, in such 
lowered position, be utilized to effect a smoothing or grading operation 
on the bottom of the excavation.

Referring to the drawings, numeral 1 indicates a digging bucket embodying 
this invention. Bucket 1 comprises a primary frame 2 of conventional 
configuration, comprising planar side walls 2a, a forward bottom wall 2b, 
and a rearwardly spaced bottom wall section 2c, which curves upwardly and 
forwardly to define a rear wall 2d of the bucket. All of these members are 
made of heavy metal sheets and are welded together in conventional 
fashion. The result is a bucket having an open bottom portion between the 
front bottom portion 2b and the rear bottom portion 2c. A plurality of 
sharpened digging teeth 3 are respectively secured to the under side of 
the forward bottom portion 2b of the primary frame 2 by suitable bolts 
(not shown). A top plate 12 is welded across the top extremities of the 
side walls 2a of the primary frame and also to the top portion of the rear 
wall 2d. In the center of the top plate 10 and rear wall 2d, a pair of 
spaced upstanding brackets 12a are respectively welded which provide 
mountings for a pivot pin 13 which secures the bucket to a boom 14 of a 
backhoe or similar excavating machine. A pin 15 traversing brackets 12a 
provides a pivotal mounting of the bucket to the actuating rod 16 of a 
hydraulic cylinder (not shown) which controls the pivotal position of the 
digging bucket with respect to the supporting boom. The open space in the 
bottom of primary frame 2 is occupied by a movable bottom member 4, which 
is of generally "U"-shaped configuration, having upstanding planar 
sidewalls 4a and a bottom wall portion 4b designed to fit snugly within 
the open bottom space provided in the primary frame structure 2. 
The movable bottom member 4 is pivotally connected to the primary frame 2 
by a pair of pivot bolts 5a which traverse appropriate apertures in the 
bottom rear corner of the side walls 4a and threadably engage threaded 
holes in the ends of a rod 5 welded to the bottom rear corner of the side 
walls 2a and rear wall 2d of the primary frame. Additionally, the side 
walls 4a of the movable bottom member 4 respectively have upwardly and 
rearwardly integral projections 4c which extend beyond the curved rear 
surface 2d of the primary frame and are rigidly secured together by a 
transverse rod 6. A pair of pivot pin brackets 8 (FIG. 2) are provided on 
the top of the rear wall 2d of the primary frame and a double-acting 
hydraulic cylinder 10 has its opposed ends respectively pivotally mounted 
to a pin 8a traversing brackets 8 and a pivot plate 6a secured to the 
transverse rod 6. Thus the movable bottom element 4 may be shifted from 
the closed position shown in FIG. 1 to an open position shown in dotted 
lines in FIG. 2, wherein the forward edge of the movable bottom 4b is 
displaced downwardly with respect to the forward bottom portion 2b of the 
primary bucket frame and below teeth 3. 
In normal digging operations, the cylinder 10 is actuated to hold the 
movable bottom 4 in its closed position, wherein the bucket 1 resembles a 
conventional bucket and the forwardly projecting digging teeth 3 are the 
primary elements utilized to engage the soil to be excavated. When, 
however, the desired excavation depth has been reached, and it is desired 
to smooth the bottom of the excavation, the digging teeth 3 are, of 
course, incapable of leaving a smooth surface along the bottom of the 
excavation. Previously it has been required to remove the digging teeth 
from the digging bucket and substitute a linear, or bladelike, digging 
edge for the digging teeth or substitute another bucket. This 
substitution, involving the loosening of relatively massive bolts or pins, 
which are always rusted and dirt-encrusted, involves a substantial amount 
of time. 
In accordance with this invention, when the excavation has reached its 
desired depth, the operator merely directs hydraulic fluid to the cylinder 
10 and moves the movable bottom portion 4b of the bucket 1 to the open, or 
down, position shown in dotted lines in FIG. 2. In this position, the 
forward edge of the movable bottom portion acts as the primary contact 
with the dirt at the bottom of the excavation and produces a smooth 
surface. 
If desired, a bladelike digging edge 4e may be permanently secured, as by 
welding, to the underside of the forward edge of the movable bottom 4b. 
This digging edge may be of hardened steel and provides greater wear 
resistance at less cost than would be required to effect the hardening of 
the forward edge of the movable bottom portion 4. It does not disturb the 
smooth bottom contour of the digging bucket when the movable bottom is 
closed, since it is disposed on the bottom side of the movable bottom 
portion 4b. 
Also, it is desirable to provide protection for the side walls 4a of the 
movable bottom portion 4 against primary impact with the dirt being 
excavated, and this may be provided by the utilization of two bars 20 
respectively secured to the outer walls of the forward portions of the 
side walls 2a of the primary bucket frame. The thickness of the bars 20 is 
somewhat in excess of that of the side walls 4a and hence effectively 
shields such side wall members from primary impact with the soil being 
excavated. 
Various modifications of the above-described structure will be apparent to 
those skilled in the art, and it is intended that all such modifications 
be included within the scope of the appended claims.