JPS6116030Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clamping device for a machine tool, etc., and more particularly to a clamping device that grips an object such as a workpiece mainly by friction or the like by moving claws toward the object.

Conventionally, in this type of clamping device, a limit switch is fixedly provided at a predetermined position during the movement of the claw toward an object to be gripped, such as a pipe, and the movement of the claw is slowed down after the claw passes the limit switch. A device was used to prevent the harmful effects of colliding with pipes etc. at high speed. However, with this device, the position where the claws start decelerating during movement is a fixed position regardless of the size of the object to be gripped, so when grasping a pipe with a small diameter, the stroke of the claws moving at deceleration may be longer than necessary. It has the disadvantage of being long and therefore creating play time. Furthermore, when gripping a pipe with a large diameter, there is a risk that the claws will collide with the pipe without being sufficiently decelerated.

The present invention was developed in view of the above circumstances, and aims to provide a clamping device in which the claws can grip the workpiece by decelerating the workpiece in response to workpieces of different diameters, and the play time can be reduced as much as possible. .

The present invention will be explained below based on drawings showing embodiments thereof. FIG. 1 is a longitudinal cross-sectional view showing a clamp device 1 according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the main parts thereof as seen from the rear side. In FIG. 1, the clamp device 1 has a frame 2, on which a pair of slides 3, 3 are mounted so as to be slidable in the lateral direction, facing each other. Claws 4, 4 are attached to opposite ends of both slides 3, 3, and a substantially V-shaped gripping surface 4a is formed at the tip of each claw 4, 4. On the other hand, a pair of cylinders 5, 5 are provided in the frame body 2. The tips of the piston rods 6,6 of the cylinders 5,5 are pivotally connected to brackets 7,7 attached to the slides 3,3 by pins 8,8. Further, a steel pipe 9 is supplied as a workpiece between the claws 4 by a supply device (not shown). Therefore, when the piston rods 6, 6 of the cylinders 5, 5 are operated to expand and contract, the claws 4, 4 move forward and backward toward the steel pipe 9, so that the steel pipe 9 is clamped or unclamped. Reference numerals 10 and 10 denote rack bars that are attached to the brackets 7 and 7 and mesh with the pinion 11 to synchronize the movements of the slides 3 and 3. Also, 12 is one rack bar 1
A linear slide guide 13 guides the rack bar 10, and a linear roller guide 13 guides the other rack bar 10.

A detection unit 20 is provided on the back side of one of the slides 3 and claws 4. The detection unit 20 has a detection body 21 and a block 22 fixed to the slide 3, as shown in FIG. The sensing body 21 includes a sensing surface 21a that is inclined parallel to one side of the approximately V-shape of the gripping surface 4a provided at the tip of the claw 4, and has a shaft 2 toward the rear thereof.
3 and a guide rod 24 are fixedly installed with screws. A rod 25 is screwed to the rear end of the shaft 23, and a shaft 26 is further screwed in a row to the rear end of the rod 25. On the other hand, the block 22 has a through hole 2 that passes through the block 22 in the direction of movement of the slide 3.
2a, a switch chamber 22b communicating with the rear of the through hole 22a, and a guide hole 22c for a guide rod 24 formed in the other. Therefore, the shaft 23,
The rod 25 and the shaft 26 are inserted into the through hole 22a, and the shafts 23 and 26 are respectively inserted into the guide bush 2.
7 and 28, and can freely slide back and forth. A spring 29 is interposed between the guide bush 28 and the rod 25. The spring 29 is connected to the sensing body 2 via the rod 25 and the shaft 23.
1, the sensing body 21 is urged such that its sensing surface 21a protrudes by a predetermined distance L from the gripping surface 4a formed at the tip of the claw 4. When an external force is applied to the detection surface 21a in the direction of movement of the slide 3, the detection body 21 moves backward by a distance L until the detection surface 21a is flush with the gripping surface 4a of the claw 4, and as the result, the rear end of the shaft 26 26a is also moved back by the dimension L.

Further, in the switch chamber 22b of the block 22, a proximity switch 31 is located by a bracket 30 at a position where it senses when the rear end 26a of the shaft 26 has moved back by a predetermined distance _L0 shorter than the L. will be installed on the The proximity switch 31 is connected to the shaft 26
When the rear end portion 26a is sensed, a detection signal S is generated, thereby switching the electromagnetic switching valve 32a of the deceleration valve 32 interposed in one of the pipes connected to the cylinder 5 to deceleration.

33 is a hydraulic power source, and 34 is a guide bush which allows the guide rod 24 to be slidably inserted into the guide hole 22c of the block 22 in the moving direction of the slide 3. Further, 35 and 36 are cover plates attached to the front and rear of the block 22.

By the way, the clamp device 1 is constructed as described above, and its operation and effect will be explained next. With the claws 4, 4 open, hold the steel pipe 9 with both claws 4, 4.
Then, the cylinders 5, 5 are actuated by hydraulic oil from the hydraulic source 3 to move the claws 4, 4 toward the steel pipe 9. In the final step of the movement, the detection surface 21a of the detection body 21 collides with the steel pipe 9. When the claws 4, 4 further move toward the steel pipe 9, the detection body 21 resists the biasing force of the spring 29 and retreats relative to the block 22 and, in turn, to the claw 4. When the sensing body 21 moves backward by L0 _or more, the moving speed of the slides 3, 3 is reduced by the detection signal S transmitted by the proximity switch 31. In this way, claw 4,
4 collides with the surface of the steel pipe 9 at a sufficiently reduced speed and grips it with a predetermined pressure. Therefore, claws 4,4
will not damage the workpiece such as the steel pipe 9. Moreover, from the time the claw starts moving toward the steel pipe 9 until the proximity switch 31 transmits the detection signal S, the claw 4
4 can move at high speed, so the efficiency of the gripping work can be improved. In particular, the feature of the present invention is that the dimension in which the pawls 4, 4 move during deceleration is L-
L ₀ and does not depend on the diameter of the steel pipe 9. Therefore, even when gripping steel pipes of different diameters, there is no risk of unnecessarily slowing down the movement of the claws 4, 4 over a long period of time, or of colliding with the surface of the steel pipe before the claws 4, 4 are decelerated sufficiently. . Of course, this also holds true when using something other than a pipe as the object to be gripped.

As is clear from the above explanation, the present invention is capable of gripping an object to be gripped at reduced speed while minimizing idle time, regardless of the size of the object, and also eliminates noise caused by collision between the workpiece and the claw. This is an extremely practical idea that can be applied to machine tools and the like to improve work efficiency without having to do anything.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a longitudinal cross-sectional view, and FIG. 2 being a longitudinal cross-sectional view of the main part seen from the back. 1...clamp device, 3...slide, 4...claw, 4
a... Gripping surface, 9... Steel pipe, 21... Sensing body, 29... Spring, 31... Proximity switch, S... Detection signal.

Claims (1)

[Scope of utility model registration request] When a long workpiece is placed in the center, a frame body, a pair of slides provided on the frame body so as to be slidable in opposition to each other in a direction transverse to the workpiece, and a pair of slides provided on the front surface of the slides and arranged in a vertical plane. V-shaped nails,
A work gripping mechanism consisting of a set of rack bars that engage from above and below with a pinion rotatably provided at the bottom of the slide and are individually connected to each slide of the set, and is capable of driving each of the slides of the set. A set of cylinders provided in the frame, a deceleration valve connected to a chamber on the waste oil side when each cylinder moves forward, and a port blocked by a detection signal from the detection body provided in parallel with the deceleration valve. A driving means comprising a first electromagnetic switching valve and a second electromagnetic switching valve that switches the supply path of pressure oil when the cylinder moves forward or backward; A sensing body that is energized by a spring whose one end is locked to a fixed member of the pawl so as to be able to protrude at all times, and that decelerates the movement of the pawl toward the workpiece when the sensing body retreats by a predetermined length or more with respect to the pawl. A clamping device comprising control means comprising a proximity switch mounted on the fixed member of the claw so as to be engageable with a detecting body that retreats to send a signal to the first electromagnetic switching valve.