Abstrict A concrete crusher has cutting shears with a first cutting arm
forming an additional arm on one of the jaws of the breaker tongs
and a second cutting arm rigidly joined to the frame of the concrete
crusher. An hydraulic piston/cylinder unit drives the jaws such
that the first cutting arm is in an open position relative to the
second cutting arm when the jaws are in an open position.
Claims I claim:
1. A concrete crusher with cutting shears, comprising:
a frame rotatably mountable on an excavator boom receptacle;
jaws defining concrete breaker tongs pivotally mounted on said
frame;
an hydraulic piston/cylinder unit drivably connected to said jaws;
a first cutting arm of the cutting shears distinct from and rigidly
joined to one of said jaws, and a second cutting arm of the cutting
shears rigidly joined to said frame;
said first cutting arm being disposed as an additional arm on one
of said jaws of said concrete breaker tongs such that, when said
first cutting arm is in an open position relative to said second
cutting arm, said breaker tongs are in an open position as well.
2. The concrete crusher according to claim 1 wherein said first
cutting arm of the cutting shears is integrally formed with said
one jaw of the concrete breaker tongs.
3. The concrete crusher according to claim 1 wherein said first
and second cutting arms define an opening of the cutting shears,
the opening being oriented approximately transversely to an opening
of the breaker tongs.
4. A concrete crusher assembly, comprising:
a frame to be mounted on an excavator boom receptacle;
a concrete crusher formed by two jaws pivotally mounted on said
frame;
an hydraulic piston/cylinder unit attached to said jaws for pivoting
said jaws;
cutting shears formed by a first cutting arm distinct from and
rigidly joined to one of said jaws, and by a second cutting arm
rigidly joined to said frame;
whereby said cutting shears are in an open position when said jaws
of said concrete crusher are in an open position, and said cutting
shears are closed when said jaws of said concrete crusher are closed.
Description BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to concrete crushers with cutting shears
and with a frame rotatably mounted on an excavator receptacle; the
jaws forming the concrete crusher, i.e., the breaker tongs, are
pivotably articulated on the frame and they are drivable by means
of a hydraulic piston/cylinder unit; one cutting arm of the shears
is rigidly joined to one of the jaws, and the second cutting arm
of the shears is rigidly mounted on the frame.
2. Description of the Related Art
A concrete crusher of the foregoing type is disclosed in U.S. Pat.
No. 4951886 to Michel Berto. One cutting arm of the shears is
formed by a blade on the backside of the associated jaw of the concrete
breaker tongs. The second arm of the shears is formed by an arm
rigidly disposed on the frame, which is located on the side of the
jaw toward the jaw blade. When the concrete breaker tongs move into
their closing position, as is the case for breaking concrete, for
instance, then the shears open. Conversely, on opening the concrete
breaker tongs, the shears are closed. This means the hydraulic piston/cylinder
unit must be acted upon in the direction opposite the direction
for breaking concrete for the purpose of opening the shears.
In that concrete crusher it is necessary, for breaking concrete,
to act upon the hydraulic piston/cylinder unit on the side of the
piston opposite the piston rod, while conversely, for cutting the
reinforcement with the shears, to act upon the hydraulic piston/cylinder
unit on the side of the piston that has the piston rod. This has
the disadvantage that only reduced forces can be brought to bear
in the cutting motion, because of the smaller piston area available,
and furthermore at high cutting resistance very high pressures occur
in the piston/cylinder unit, which severely strain the seal between
the piston rod and the cylinder bottom.
Similar types of concrete crushers are disclosed in U.S. Pat. Nos.
4196862 to Tagawa; 4776524 to Sakato; 4719975 and 4838493
to LaBounty; and 4512524 to Shigemizu.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a concrete
crusher with cutting shears, which overcomes the above-mentioned
disadvantages of the prior art devices and methods of this general
type and which enables the application of maximum crushing and cutting
forces for each operation, while placing the least possible strain
on the hydraulic system.
With the foregoing and other objects in view there is provided,
in accordance with the invention, a concrete crusher with cutting
shears, comprising:
a frame rotatably mountable on an excavator boom receptacle;
jaws defining concrete breaker tongs pivotally mounted on the frame;
an hydraulic piston/cylinder unit drivably connected to the jaws;
a first cutting arm of the cutting shears rigidly joined to one
of the jaws, and a second cutting arm of the cutting shears rigidly
joined to the frame;
the first cutting arm being disposed as an additional arm on one
of the jaws of the concrete breaker tongs such that, when the first
cutting arm is in an open position relative to the second cutting
arm, the breaker tongs are in an open position as well.
In other words, the above-mentioned objects are satisfied in that
the movable cutting arm of the shears is disposed as an additional
arm on the associated jaw of the concrete crusher (the breaker tongs).
Further, the movable cutting arm is located in the open position
of the shears when the breaker tongs are in the open position. As
a result it is possible to handle both operating motions via the
cylinder chamber remote from the piston rod, and therefore a high
operating pressure is attainable in the cutting motion as well,
without excessively straining the seal provided by externally sealing
parts.
In accordance with an added feature of the invention, the first
cutting arm of the cutting shears is integrally formed with the
one jaw of the concrete breaker tongs.
In accordance with a concomitant feature of the invention, the
first and second cutting arms define an opening of the cutting shears,
the opening being oriented approximately transversely to an opening
of the breaker tongs.
Advantageously, the movable cutting arm of the shears are integrally
formed with the associated jaw of the concrete breaker tongs. As
a result, a very sturdy crusher is provided which is essentially
invulnerable to malfunction. When the opening of the shears is oriented
approximately transversely to the opening of the crusher tongs,
the tongs hinder neither the gripping nor the cutting motion when
the shears are pivoted in the working direction The same is also
true for the concrete breaker tongs with respect to the cutting
shears, since in the operating position of the concrete breaker
tongs, the cutting shears are pivoted out of operating range.
Other features which are considered as characteristic for the invention
are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied
in a concrete crusher with cutting shears, it is nevertheless not
intended to be limited to the details shown, since various modifications
and structural changes may be made therein without departing from
the spirit of the invention and within the scope and range of equivalents
of the claims.
The construction of the invention, however, together with additional
objects and advantages thereof will be best understood from the
following description of the specific embodiment when read in connection
with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is an front elevational view of a first embodiment, including
a partial illustration of an excavator boom;
FIG. 2 is a rear elevationai view of the first embodiment in the
closed position of the breaker jaws and shears, with the excavator
boom and the upper part of the connecting not illustrated for clarity;
FIG. 3 is a rear elevational view thereof with the upper part of
the frame removed;
FIG. 4 is a view similar to FIG. 3 but with the frame closed;
FIG. 5 is an end view of the embodiment of FIG. 4;
FIG. 6 is a view similar to FIG. 4 of a second embodiment; and
FIG. 7 is a view similar to FIG. 6 with the front plate of the
frame removed.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first,
particularly, to FIG. 1 thereof, there is seen a first exemplary
embodiment of the invention with an excavator boom 1 (also referred
to as a jib). A coupling body 3 is mounted on the boom 1 via a
coupling 2. The coupling body 3 at its distal end from the coupling
2 has a pivot joint 4 through which the coupling body 3 carries
a frame 5 for the concrete breaker tongs with cutting shears of
the invention. The pivot joint allows the concrete breaker tongs
with the cutting shears to be rotated relative to the excavator
boom.
The frame 5 has a front cover plate 6 and a rear cover plate 7
between which breaker jaws 8 and 9 for breaking concrete are supported
via pivot shafts 10 and 11 respectively. The two breaker jaws 8
and 9 are pivotable toward one another via an hydraulic piston/cylinder
unit 12 13 14. The hydraulic piston/cylinder unit engages the
jaws 8 and 9 through pivot bolts 15 and 16. The jaws 8 9 thus form
two-armed levers, the front side of which serves the purpose of
concrete crushing and engages the hydraulic piston/cylinder unit
12 13 14 on the other end via the aforementioned pivot bolts 15
16.
A cutting arm 17 is rigidly mounted on the frame 5 in the present
case on the rear cover plate 7. The cutting arm 17 carries a blade
18 that cooperates with blades 20 21 provided on the second cutting
arm 19 to cut metal reinforcements (rebars and the like) found in
reinforced concrete structures. The second cutting arm 19 in this
case is integrally formed with the jaw 8 of the concrete crusher.
It should be understood that, naturally, the cutting arm 19 could
be a separate component mounted by conventional connecting means.
The blades 20 and 21 form an obtuse angle with one another, specifically
in such a way that the opening angle of the blade 21 approaching
the tip of the cutting arm 19 is smaller than that of the blade
20. As a result, when metal reinforcements are cut the material
is prevented from slipping out of the shears. For the same purpose,
and also for receiving the material more easily, a receptacle 27
for cutting material is provided on the outermost end of the cutting
arm 17 on the outer end of the blade 18. The receptacle 27 projects
beyond the cutting arm 17 toward the other cutting arm 19 and the
frontmost edge of the receptacle 27 is joined toward the blade 18
via an inclined face which, when the shears close, deflects cutting
material, resting on the front end of the receptacle 27 toward
the rear.
The motions of the jaws 8 9 are controlled via stops; one of the
jaws is formed with an oblong hole 23 (a circularly arcuate hole
23), that is penetrated by a stop bolt 22. The ends of the oblong
hole limit the motion of the jaw 9. The jaw 8 conversely has a stop
lug 24 which in the opened state rests on a stop 26 and in the
closed state on a stop 25. The stop limitation of the jaws 8 9
is provided because the hydraulic piston/cylinder unit 12 13 14
is freely suspended between the two jaws, so that the effect of
the stops is that both in the open position and the closed position,
the jaws 8 9 are always located in the same position relative to
one another.
The movement of the cutting arm 19 which is formed integrally
with the jaw 8 is also controlled via the stop lug 24 and the stops
25 26. Accordingly, the stop also determines the various positions
of the cutting shears.
With reference to FIG. 3 the pressure introduction for closing
the jaws 8 9 and thus also for closing the shears 17 19 is effected
such that the chamber of the cylinder 12 located before the piston
13 that is, the cylinder chamber opposite the piston rod 14 is
acted upon by pressure. It is thus accomplished that in the closing
motion of not only the jaws 8 9 of the concrete crusher but also
the cutting arms 17 19 of the cutting shears, the entire piston
surface area is acted upon by pressure, so that higher cutting forces
can be brought to bear. The cylinder chamber located behind the
piston 13 and penetrated by the piston rod 24 is acted upon by pressure
only for the opening motion, that is, for a motion in which no noteworthy
counterpressure or virtually no counterpressure occurs, so that
the lesser piston area available is readily sufficient for imposing
pressure, and moreover the leadthrough of the piston rod 14 through
the bottom of the cylinder 12 is stressed only by the lower pressure
necessary for the opening motion.
In the variant embodiment of FIGS. 1-5 the opening of the cutting
shears points approximately transversely to the opening of the breaker
tongs laterally of the breaker tongs. With particular reference
to FIG. 5 the cutting shears are located in the same plane as the
breaker tongs. Such an embodiment has the advantage that whichever
tool is not in use at a given time protrudes laterally away from
the tool that is in use, so that two tools can be used without affecting
or hindering one another.
In the variant embodiment of FIGS. 6 and 7 the opening of the
cutting shears points laterally away from the opening of the breaker
tongs by only a small acute angle. The two tools are located in
the same plane, side by side. Such an embodiment makes it possible
to work without major swiveling in the region of the coupling 2
between the excavator arm 1 and the coupling body 3. The one slight
disadvantage is that, when the crusher of the invention is used
in working on the ground, work-related material lying around can
hinder the use of one tool or the other. In both these FIGS. 6 and
7 the operative components that are the same as in the embodiment
of FIGS. 1-5 are identified by the same reference numerals, except
that the reference numerals have been changed for the modified parts
only, namely for the cutter arms to 17' and 19' and for the blades
to 18' and 20'.
The mode of operation with regard to piston/cylinder unit and the
advantageous force introduction is the same, in the embodiment of
FIGS. 6 and 7 as in the embodiment of FIGS. 1-5. |