GRIPPER

Abstract

A gripper having at least two gripper arms movably arranged in a pincer-like manner on a base part and a cutting device for material to be cut for attachment to a processing machine, wherein the cutting device is formed by a cutting plate, which is movable by a piston-cylinder unit from an active position, in which the cutting plate projects into a receiving space for the material to be cut enclosed by the gripper arms, into an inactive position, in which the cutting plate is retracted in the base part. The retractable and extendable piston rod of the piston-cylinder unit is connected to the cutting plate via a driver pin which, in the active position of the cutting plate, rests against an abutment of the base part when the cutting plate is loaded.

Claims

1. A gripper having at least two gripper arms arranged in a pincer-like manner on a base part so as to be movable relative to one another and a cutting device for material to be cut for attachment to a processing machine, wherein the cutting device is formed by a cutting plate which can be moved with the aid of a piston-cylinder unit from an active position, in which the cutting plate projects into a receiving space for the material to be cut enclosed by the gripper arms, into an inactive position, in which the cutting plate is retracted in the base part, wherein the cutting plate is pivotably mounted on the base part about a first pivot axis perpendicular to the cutting plate, and the cylinder of the piston-cylinder unit is pivotably mounted on the base part about a second pivot axis parallel to the first pivot axis, wherein the retractable and extendable piston rod of the piston-cylinder unit is connected to the cutting plate via a driver pin which, in the active position of the cutting plate, rests against an abutment of the base part when the cutting plate is loaded, wherein the driver pin is guided via ball bearings in a link guide of the base part, the clear cross-section of which widens in the region of the abutment to ensure a spacing of the ball bearings from the leading cam track of the link guide when the driver pin rests against the abutment.

2. The gripper according to claim 1, wherein the cutting plate is arranged between two guide plates of the base part, which define two mutually facing, parallel guide planes for the cutting plate, wherein the guide plates comprise an opening in their respective central region for the movement path of the piston-cylinder unit.

3. The gripper according to claim 2, wherein the link guide is formed by two link frames which are each fastened or formed on one of the two guide plates lying one above the other and each have an end section with an enlarged clear cross-section, wherein the abutment is formed by marginal edges of the guide plates which, in a viewing direction oriented perpendicularly to the guide plates, narrow the widened clear cross-section of the link frames.

4. The gripper according to claim 1, wherein the cutting edge of the cutting plate facing the receiving space and a rear marginal edge of the cutting plate extend at an acute angle to one another, the apex of which lies in the region of the first pivot axis, and merge into one another in their regions facing away from the first pivot axis via an arcuate edge.

5. The gripper according to claim 4, wherein the longitudinal axis of the piston-cylinder unit is substantially parallel to the rear marginal edge of the cutting plate.

6. The gripper according to claim 1, wherein the driver pin is fixed to a free end of the piston rod of the piston-cylinder unit, wherein the driver pin is oriented with its longitudinal axis perpendicular to the cutting plate and engages a hook-shaped extension of the cutting plate.

7. The gripper according to claim 1, wherein the cutting device is designed as a retrofit part of the gripper.

8. A processing machine comprising a gripper according to claim 1.

Description

[0014] The invention is explained in more detail below by means of an exemplary embodiment with the aid of the accompanying figures. The figures show as follows:

[0015] FIG. 1 shows a perspective view for a section along the sectional plane B-B of FIG. 4b of a gripper according to the invention having a cutting device in the inactive position as seen from below,

[0016] FIG. 2 shows a perspective view of a gripper according to the invention having a cutting device in the inactive position as seen from above,

[0017] FIG. 3 shows a perspective view for a section along the sectional plane G-G of FIG. 8b of a gripper according to the invention having a cutting device in the active position as seen from below,

[0018] FIG. 4a shows a sectional view according to the sectional plane B-B of FIG. 4b for a gripper according to the invention having a cutting device in the inactive position,

[0019] FIG. 4b shows a side view of a gripper according to the invention having a cutting device in the inactive position,

[0020] FIG. 5 shows a detailed view of “Detail N” of FIG. 4a,

[0021] FIG. 6 shows a sectional view according to the sectional plane J-J of FIG. 4a for a gripper according to the invention having a cutting device in the inactive position,

[0022] FIG. 7 shows a detailed view of “Detail K” of FIG. 6,

[0023] FIG. 8a shows a sectional view according to the sectional plane G-G of FIG. 8b for a gripper according to the invention having a cutting device in the active position,

[0024] FIG. 8b shows a side view of a gripper according to the invention having a cutting device in the active position,

[0025] FIG. 9 shows a detailed view of “Detail M” of FIG. 8a,

[0026] FIG. 10a shows a sectional view according to sectional plane A-A of FIG. 10b for a gripper according to the invention having a cutting device in the active position,

[0027] FIG. 10b shows a side view of a gripper according to the invention having a cutting device in the active position,

[0028] FIG. 11 shows a sectional view according to the sectional plane D-D of FIG. 10a for a gripper according to the invention having a cutting device in the active position, and

[0029] FIG. 12 shows a detailed view of “Detail L” of FIG. 10a.

[0030] First, reference is made to FIGS. 1-3, which show a gripper according to the invention having a cutting device in the inactive position (FIGS. 1 and 2) and in the active position (FIG. 3). The cutting device is arranged at the lower end of a base part 1. At the front end of the base part 1, two gripper arms 2, 3 are provided, which are arranged on the base part 1 in a pincer-like manner so as to be movable relative to one another. The two gripper arms 2, 3 are preferably acted upon with closing pressure by hydraulic means known per se, in order to firmly embrace and hold the material to be cut in a receiving space located between them. When the gripper arms 2, 3 are closed around the material to be cut, the gripper arms 2, 3 move towards each other. When the gripper arms 2, 3 are opened hydraulically, the gripper arms 2, 3 move away from each other to release the material to be cut. The gripper arms 2, 3 and the base part 1 have a surface with tooth-shaped projections 4 in sections on their side facing the material to be cut. When the gripper arms 2, 3 are closed around the material to be cut with closing pressure, the tooth-shaped projections 4 engage in the material to be cut in order to strengthen the fixation of the material to be cut.

[0031] A connecting device, not shown in more detail, is provided at the rear of the base part 1. The connection device is used to attach the base part 1 to a processing machine, such as the boom arm of an excavator or another processing machine, which can accommodate the connection device and support the weight of the material to be cut via the base part 1. The connection device is also used to connect the hydraulic lines for controlling the gripper arms 2, 3 and the cutting device.

[0032] The cutting device can also be designed as a retrofit part and in this case is attached to the lower end of a base part 1, for example by means of screw connections. The cutting device comprises a cutting plate 5, as well as a piston-cylinder unit 6 which moves the cutting plate 5, two guide plates 7a, 7b for the cutting plate 5, as well as two outer link frames 8a, 8b of a link guide 8. The cutting device may further comprise a cover 9 attached to the base part 1, which accommodates the cutting device and is open on the outlet side of the cutting plate 5.

[0033] As can also be seen in particular in FIGS. 4, 8 and 10, the guide plates 7a, 7b of the base part 1 are arranged parallel to one another in the exemplary embodiment shown, and they have an opening in their respective central region for the movement path of the piston-cylinder unit 6. A link frame 8a, 8b is attached or formed on each of the outer sides of the two guide plates 7a, 7b facing away from each other, which together form a link guide 8. Between the two guide plates 7a, 7b, the cutting plate 5 is pivotably arranged on the base part 1 about a first pivot axis S.sub.1 perpendicular to the cutting plate 5. In the vicinity of the first pivot axis S.sub.1, a pivot bearing of the piston-cylinder unit 6 is arranged with a second pivot axis S.sub.2, which is parallel to the first pivot axis S.sub.1. The longitudinal axis of the piston-cylinder unit 6 extends essentially along a rear marginal edge of the cutting plate 5 facing away from the cutting edge 10. In the exemplary embodiment shown, the cutting plate 5 is designed in such a way that the cutting edge 10 and the rear marginal edge extend at an acute angle to one another, the apex of which lies in the region of the first pivot axis S.sub.1, and merge into one another in their regions facing away from the first pivot axis S.sub.1 via an arcuate marginal edge. The cutting plate 5 therefore has an approximately circular sector-shaped appearance.

[0034] The piston-cylinder unit 6 is hinged with its cylinder to the pivot bearing with the second pivot axis S.sub.2 on the base part 1. As mentioned, the cylinder extends essentially along a rear marginal edge of the cutting plate 5 facing away from the cutting edge 10 and has a piston rod which is provided with a driver pin 11 at its free end. The driver pin 11 is oriented with its longitudinal axis perpendicular to the cutting plate 5 and engages in a hook-shaped extension of the cutting plate 5 (see FIGS. 8a and 9), which is designed in such a way that, during an extension or return movement of the piston rod, the linear positioning movement of the piston rod is converted into a pivoting movement of the cutting plate 5 about the first pivot axis S.sub.1. In the process, the driver pin 11 is guided by the link guide 8, in which the driver pin 11 is mounted by means of two ball bearings 12a, 12b arranged at the end of the driver pin 11. The driver pin 11 is thus guided at its two ends via the ball bearings 12a, 12b in the two outer link frames 8a, 8b of the link guide 8 and penetrates in its central region the clear opening of the hook-shaped extension of the cutting plate 5, where the piston rod of the piston-cylinder unit is also fastened, as can be seen for example in FIG. 6 and FIG. 7.

[0035] In the inactive position of the cutting plate 5, the driver pin 11 is located in an end section of the link guide 8 facing the second pivot axis S.sub.2, as can be seen in FIGS. 4-7. The cutting plate 5 is in its retracted position and is held in this position with the aid of the piston-cylinder unit 6.

[0036] By actuating the piston-cylinder unit 6 and an extension movement of its piston rod, the driver pin 11 is moved in the direction of the end section of the link guide 8 facing away from the second pivot axis S.sub.2, wherein the driver pin 11 rolls along the corresponding cam guide tracks of the link guide 8 via the two ball bearings 12a, 12b. This extension movement is converted into a pivoting movement of the cutting plate 5 about the first pivot axis S.sub.1 and is very smooth-running due to the ball bearings 12a, 12b used, so that the piston-cylinder unit 6 can be dimensioned to be correspondingly small.

[0037] At the end of the extension movement of the piston rod, the cutting plate 5 finally reaches its active position, in which the cutting edge 10 projects into the receiving space enclosed by the gripper arms 2, 3, as can be seen in FIG. 8a and FIG. 10a. At its end section facing away from the second pivot axis S.sub.2, the link guide 8 has a widened clear cross-section compared to its end section facing the second pivot axis S.sub.2 (see in particular FIG. 12), which is crossed by the guide plates 7a, 7b in a viewing direction oriented perpendicular to the guide plates 7a, 7b. In a viewing direction oriented perpendicular to the guide plates 7a, 7b, these transverse marginal edges narrow the widened clear cross-section of the link frames 8a, 8b and form the abutment for the driver pin 11. As soon as the driver pin 11 reaches the end section of the link guide 8 facing away from the second pivot axis S.sub.2, it comes into contact with its pin shell with these transverse marginal edges of the guide plates 7a, 7b, as can be seen in FIGS. 8-12, wherein spacer rings 13 can also be provided for this purpose, which can be seen in particular in FIG. 11. In this active position of the cutting plate 5, the marginal edges of the guide plates 7a, 7b, which cross the expanded clear cross-section of the link guide 8, form the abutment for the driver pin 11, via which forces acting in the cutting plate plane can be dissipated into the base part 1. The enlarged clear cross-section of the link guide 8 in this end section ensures that the ball bearings 12a, 12b are exposed, i.e. do not rest against the leading cam track of the link guide 8. The ball bearings 12a, 12b are thus completely relieved of load when the cutting plate 5 is loaded and are therefore not subject to wear. Residual load forces are dissipated via the pivot bearing for the first pivot axis of the cutting plate 5, but these are small. The majority of the loads on the cutting plate 5 act as a torque acting about the first pivot axis, which is dissipated by the driver pin 11 and its direct contact with the abutment of the base part 1.

[0038] It is thus immediately apparent that with the gripper according to the invention, the load-bearing capacity of the cutting device is increased and its wear reduced accordingly, while the gripper can still be designed to be compact. This means that the cutting device can also be retrofitted for a gripper.