Abstrict The present invention provides a concrete crusher comprising an
upper jaw and a lower jaw which are connected to each other through
a pivot pin and adapted to be opened and closed by a hydraulic cylinder,
the lower jaw having a plurality of longitudinal cutters extending
perpendicular to the pivot pin and arranged in the form of a fork,
the upper jaw having a large rough cutter extending perpendicular
to the pivot pin, the lower jaw further having a plurality of cross
cutter bars arranged in a grate-like pattern avoiding the position
of descent of the large rough cutter, the upper jaw further having
a surfacing plate member facing the lower jaw and having a plurality
of cross cutter bars corresponding to the cross cutter bars of the
lower jaw, with the large rough cutter interposed between rows of
the cross cutter bars of the upper jaw.
Claims What is claimed is:
1. A concrete crusher comprising an upper jaw and a lower jaw which
are connected to each other through a pivot pin and adapted to be
opened and closed by a hydraulic cylinder, said lower jaw having
a plurality of longitudinal cutters extending perpendicular to said
pivot pin and arranged in the form of a fork, said upper jaw having
a large rough cutter extending centrally on a surfacing plate member
and perpendicular to said pivot pin, said lower jaw further having
a plurality of short cross cutter bars disposed on said longitudinal
cutters in the form of a grate-like pattern avoiding the position
of descent of said large rough cutter and a long cross cutter bar
disposed on and transversing all of said longitudinal cutters at
a position rearwardly spaced from and parallel to said short cross
cutter bars, said upper jaw having on said surfacing plate member
a plurality of short cross cutter bars corresponding to said short
cross cutter bars of the lower jaw on either side of said large
rough cutter and a long cross cutter bar corresponding to said long
cross cutter bar of the lower jaw, said short and long cross cutter
bars of the lower jaw projecting from a plane defined by said longitudinal
cutters and said short and long cross cutter bars of the upper jaw
projecting from said surfacing plate member so that they abut against
each other when the lower and upper jaws are fully closed, and said
cross cutter bars being replaceable when worn by new cross cutter
bars welded in place.
2. The concrete crusher of claim 1 further including span members
disposed in spaced relation to one another between said longitudinal
cutters of said lower jaw.
3. The concrete crusher of claim 1 wherein the cross-cutter bars
are rectangular in cross-section.
Description FIELD OF THE INVENTION
The present invention relates to a concrete crusher.
BACKGROUND OF THE INVENTION
In the demolition of buildings and other structures, crushing of
concrete is generally carried out using a chisel (teeth) device
which is opened and closed by a hydraulic jack. Known as a concrete
crusher, this device comprises a pair of jaws for biting concrete
as secured to the free end of the driving arm of a construction
machine, typically a power shovel, a hydraulic cylinder for opening
and closing said jaws, and chisel or crushing means attached to
the mating faces of the jaws.
In order that the crushing capacity of such a concrete crusher
may be increased, it is important to insure that the output of the
hydraulic cylinder will act on the crushing chisel means as a concentrated
load and also that, in consideration of the fact that concrete is
rather resistant to compressive forces, the crushing force will
act not as a compressive force but as a bending moment. Several
proposals have been made in accordance with the above deign concepts.
For example, it was proposed to provide the mating faces of a pair
of jaws with crushing means each comprising a plurality of projecting
bars arranged in parallel with a pivot pin but in staggered relation
between the jaws so that the output of a hydraulic cylinder may
act as a concentrated load and, at the same time, exert bending
moments on the concrete (Japanese Patent Publication No. 58-14909).
It was also proposed to provide a pair of jaws, with the lower
jaw having on its mating face a plurality of longitudinal cutters
arranged in the form of a fork and perpendicular to a jaw pivot
pin and a plurality of auxiliary cutters as arranged between said
longitudinal cutters and perpendicular to the latter to constitute
a grate-like cutter system, while the upper jaw is provided on its
mating surface with a large sharp-pointed rough crushing cutter
perpendicular to said pivot pin and a plurality of sharp-pointed
cutters (chisels) directed against said grate-like cutting system
of the lower jaw. In this arrangement, a concentrated load is applied
to the large rough crushing cutter to rough-cut the concrete in
the first place and, then, bending moments are applied to the concrete
by means of the grate-like cutting system of the lower jaw and the
chisels of the upper jaw (Japanese Patent Publication No. 1-27504).
It has also been proposed to provide a concrete crusher such that,
in the crusher arrangement proposed in said Japanese Patent Publication
No. 1-27504 said large rough-cutting tool is omitted and, instead,
the upper jaw is provided with a multiplicity of chisels corresponding
to the meshwork of the grate-like cutting system of the lower jaw
(Japanese Kokai Patent Application No. 60-113258 Japanese Utility
Model Publication No. 61-28839).
However, in all of the crashers referred to above, the cutters
are arranged in staggered relation so that bending moments may act
on the concrete to achieve an improved crushing effect but the crushing
cutters tend to be worn rapidly just because they act to produce
bending moments and particularly if the cutters are chisels, they
must be replaced at short intervals.
OBJECTS AND SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to provide a concrete
crusher having an improved concrete crushing efficiency.
It is another object of the invention to provide a concrete crusher
which is sturdy and easy to maintain.
It is a still further object of the invention to provide a concrete
crusher which can be manufactured at low cost.
To accomplish the above objects, the invention provides a concrete
cutter comprising an upper jaw and a lower jaw which are connected
to each other through a pivot pin and adapted to be opened and closed
by a hydraulic cylinder, said lower jaw having a plurality of longitudinal
cutters extending perpendicular to said pivot pin and arranged in
the form of a fork, said upper jaw having a large rough cutter extending
perpendicular to said pivot pin, said lower jaw further having a
plurality of cross cutter bars arranged in a grate-like pattern
avoiding the position of descent of said large rough cutter, said
upper jaw further having a surfacing plate member facing said lower
jaw and having a plurality of cross cutter bars corresponding to
said cross cutter bars of the lower jaw, with said large rough cutter
interposed between rows of said cross cutter bars of the upper jaw.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a disassembled perspective view showing an embodiment
of the invention; and
FIG. 2 is a side-elevation view, in partial section, of the same
embodiment .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The constitution and operation of the invention are now described
in detail with reference to the accompanying drawings;
The illustrated embodiment is relevant to an attachment-type concrete
crusher having a reinforcement cutter for fine fragmentation of
concrete which can be detachably secured to the free end of the
driving arm of a power shovel. The illustrated crusher has a tip
opening width of 850 mm, an upper jaw width of 330 mm and a lower
jaw width of 560 mm, and has a tip crushing capacity of 80 tons.
The reference numeral 1 indicates a crusher housing which is integrally
formed with a lower jaw 2. The lower jaw 2 is, therefore, stationary.
Juxtaposed with this lower jaw 2 is a movable upper jaw 3 which
is swingably supported by a pivot pin 4 traversing the housing 1.
Connected to the upper side of this upper jaw 3 is a piston rod
7 of a hydraulic cylinder 6 which is mounted through a connecting
pin 5 within said housing 1. Therefore, as this hydraulic cylinder
6 is actuated by the hydraulic pressure from a hydraulic oil pump
(not shown) mounted on a power shovel (not shown), the upper jaw
3 is opened or closed with respect to the lower jaw 2. Furthermore,
the inner base portion of the lower jaw 2 is provided, on one side
thereof, with a lower reinforcement cutter 8 while the upper jaw
3 is equipped with an upper reinforcement cutter 9 in the corresponding
position for cooperative shear operation.
While the foregoing is the arrangement adopted in the conventional
concrete crushers as well, the concrete crusher of this embodiment
is further provided with the crushing cutter means described below.
Thus, the lower jaw 2 is provided with four longitudinal cutters
1010 . . . arranged in the form of a fork and perpendicular to
said pivot pin 4. Respectively disposed on pairs of adjacent longitudinal
cutters 1010 and 1010 which are located on the right-hand and
left-hand sides as viewed, are short cross cutters 11 and 11 which
are steel bars of rectangular section. In addition, short cross
cutters 12 are disposed on the longitudinal cutters 1010 . . .
as illustrated. Further disposed on said longitudinal cutters 1010
. . . , in a position closer to their bases and transversing all
the four longitudinal cutters 1010 . . . , is a single elongated
cross cutter 13. Disposed under said short cross cutters 1111 are
span members 14 spanning the longitudinal cutters 1010 . . . for
added rigidity. The span members 14 serve, also, as guides for letting
out crushed concrete. Thus, the longitudinal cutters 1010 . . .
and short cross cutters 11 constitute a grate-like cutter system.
However, because of the absence of short cross cutters 11 between
the middle two longitudinal cutters 1010 there is formed a rectangular
through-opening which is larger than the grate 15 of said grate-like
cutter system.
The longitudinal cutters 1010 . . . , cross cutters 111213 and
span members 14 are rectangular bars of high tension steel and,
when worn, the short and long cross cutters 11 12 and 13 in particular,
can be easily replaced with new ones by welding. The forward end
of each longitudinal cutter 10 is pointed and only span members
17 are interposed in the forward end portion of the lower jaw, without
provision of any cross cutter, so as to assist in scooping of concrete.
The upper jaw 3 has a plate member 18 constituting its side facing
the lower jaw 2 and this plate member 18 is provided with short
and long cross cutters corresponding to said short and long cross
cutters 11 12 and 13 of the lower jaw 2. In addition, a longitudinally
elongated rough cutter 21 is interposed between rows of said short
cross cutters 1919 . . . Therefore, as the upper and lower jaws
32 are closed, said short and long cross cuter bars 111213 and
said cutter bars 19 . . . and 20 are abutted against each other
and the opening 16.
The operation of this embodiment is now described. With the upper
and lower jaws 32 in the open position, the concrete is scooped
up by the forward ends of the longitudinal cutters 10. Then, as
the upper and lower jaws 32 are closed, the large rough cutter
21 crushes the concrete into coarse fragments to reduce the crushing
resistance in the subsequent crushing operation. Then, the upper
and lower cross bars 111213 and 1920 crush the coarse concrete
fragments into finer fragments. Since the upper and lower cross
cutters 111213 and 1920 are abutted against each other, the bending
moments characteristic of staggered chisels are not obtained but
inasmuch as the concrete has already been broken into coarse fragments,
a high crushing efficiency is insured. The resulting fine fragments
of concrete fall through the grates 15 and through-opening 16 as
well as along the lateral sides of the upper and lower jaws 32
but since the short cross cutters 19 of the upper jaw 3 do not fit
into the grates 15 the finely divided concrete is allowed to fall
readily, with the result that the short cross cutters 19 . . .
do not encounter any remarkable resistance of the crushed concrete.
It should be understood that while the cross cutters in the above
embodiment were constituted by rectangular bars, bars of other configurations
can also be employed.
Thus, in accordance with the present invention wherein the mating
faces of the upper and lower jaws are provided with projecting cross
bars which are abutted against each other on closure of the jaws,
the concrete is crushed by mere contact of these cross cutters but
since the concrete is first split by a large rough cutter, the crushing
of concrete proceeds easily, without undue forces acting on the
cross bars, thus insuring a long service life. Moreover, since the
cross bars are mere steel bars, they can be easily replaced with
new ones at low cost. |