JPH03184704A - Differential four jaw chuck - Google Patents

Abstract

PURPOSE:To surely hold a holding body and to correctly set at the specific position, by providing a mechanism capable of centripedally holding whatever deformed body by working four jaws effectively on the differential four-jaw chuck used for an assembly robot, etc. CONSTITUTION:When a pressure air is fed to an air feeding port 30, pistons 7, 8 are made apart each other, an output shaft 9 is advanced, an output shaft 10-retreated, jaws 14, 14' in cross one direction and jaws 15, 15' in cross other direction are driven together in the cylinder axial direction. By this driving either one jaw of the jaws 14, 14', 15, 15', for instance, the claw 14 is abutted on a holding body, then, the holding body is moved in the direction of the jaw 14' together with the movement of the jaw 14 and the piston 7 is stopped at the place where both 14, 14' are abutted on the holding body. Thereafter the piston 8 is retreated and the piston 8 that the jaws 15, 15' in the cross other direction are abutted on the holding body is stopped also. Now the equivalent air pressure exerting a reaction force each other is applied on the pistons 7, 8 and it is automatically made centripedal and held with the uniform fastening forces of the jaws 14, 14', 15, 15'.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a differential four-jaw chuck that can stably and centripetally grip an irregularly shaped object.

[Prior art and problems to be solved by the invention] Conventionally, a four-sided clamping type chuck such as a pneumatic hand used for assembly robots, etc. has four jaws arranged in a cross that uniformly interlock in the same direction. When grasping objects of the same shape continuously, even if the position of the claws is adjusted slightly according to the shape of the object, there may be variations in the finished dimensions of the object. Depending on the way the object is fed, the claws may play when gripping, making it impossible to grip the material stably and dropping the material, or grasping the object too strongly to avoid dropping it may damage or deform the object. There are inconveniences such as making it impossible to set the held object accurately in a predetermined position.

The present invention aims to solve the above-mentioned disadvantages of the conventional four-sided clamp chuck, and was devised based on a completely new idea. The four claws work effectively without the need for initial adjustment, allowing for secure and centripetal gripping.
The gripping method can be changed to various gripping methods such as internal tightening, external tightening, internal tightening in one direction and external tightening in the other direction depending on the shape of the object to be grasped, and the driving method can also be pneumatic, hydraulic, manual, etc.
The purpose is to provide a differential four-jaw chuck in which any method can be selected depending on the factory equipment.

[Means to solve the problem]

In order to achieve the above object, the present invention takes out the respective output shafts of two pistons inserted in series in a cylinder body in the same direction on a common axis, and opposes the taken-out portions of the respective output shafts in two cross directions. The two pistons are driven in opposite directions until the pair of opposite pawls in each direction of the cross are brought into contact with the object to be held and are stopped. It features a differential four-jaw chuck with a bottom that grips objects.

[For production]

When the two pistons are driven in opposite directions, the pair of opposing pawls engaged with the output shafts of both pistons are driven toward the center of the cylinder in the open or close direction, and the cross When one of the claws in a pair of opposing claws comes into contact with the object being held, the object is moved by this claw in the direction of the other opposing claw, and when both claws come into contact with the object, both claws are driven. One of the pistons that drives the claws in the other direction of the cross is stopped, and then the other piston that drives the claws in the other direction of the cross moves differentially, and one of the claws of the pair of opposing claws in the other direction of the cross comes into contact with the grasped object. is moved by this claw in the direction of the other opposing claw, and when both claws come into contact with the object to be held, the pistons that drive both claws stop. At this time, equal driving forces are acting on the rain pistons that react with each other, so even if the object to be gripped is irregularly shaped, the object to be gripped will be tightened with equal tightening force and centripetal It will be held by.

〔Example〕

The present invention will be explained in detail below based on illustrated embodiments.

The embodiment shown in FIGS. 1 and 2 is the most basic pneumatic internal clamp type differential four-jaw chuck of the present invention, which is driven by pneumatic pressure and simultaneously closes the watermelon in the axial direction. The figure is a developed sectional view taken along a 90-degree fold line passing through the claws in two cross directions of the chuck, and FIG. 2 is a front view of the chuck.

In the figure, 1 is a pneumatic internal clamping type differential four-jaw chuck, 2
is a cylindrical cylinder body; 3 is a front cover screwed onto the entire surface of the cylinder body 2 with bolts 4; 5 is a rear cover screwed onto the rear surface of the cylinder body 2 with a port 6; A first piston 7 and a second piston 8 are inserted in series into the bore 2a, and a hollow output shaft 9 of the first piston is concentrically screwed into the front surface of the first piston 7. On the front surface, the output shaft 10 of the second piston, which is slidably fitted into the shaft hole of the hollow output shaft 9 of the first piston, and which is longer than the output shaft 9 of the first piston, is concentrically screwed into the hole 1. has been done. Link attachment portions 12 and 13 are formed at the tip ends of the output shaft 9 of the first piston and the output shaft 10 of the second piston, respectively, and protrude in the diametrical direction. is provided with a groove 12a into which the link attachment part 13 of the output shaft 10 of the second piston can be fitted in the cross direction, and when the output shaft 9 of the first piston moves forward and the output shaft 10 of the second piston moves backward, both outputs are The link attachment portion 12.13 at the tip of the shaft 9.10 can be moved to the same position. Note that the output shafts 9 and 10 of both the first piston 7 and the second piston 8 are made separate and assembled with screws in consideration of the assembly and disassembly of the chuck 1.

The front cover 3 has the first section in the center. A circular hole 3a in which both link mounting portions 12.13 at the tips of the output shafts 9.10 of both second pistons can slide, and grooves 3b in two cross directions.

3c, a pair of opposing claws 14.14' and 15.15' are pivotally supported by a pin 16 in the direction of the cylinder center so as to be freely openable and closable in both grooves 3b and 3c, and a pair of opposing claws 14. The base of 14' is connected to the link attachment part 12 of the output shaft 9 of the first piston by a pair of opposite pawls 15.
The base of 15' has links 17.1 and 17.1, respectively, in which the links 7 of the output shaft 10 of the second piston are arranged perpendicularly to the link mounts 12 of the output shaft 9 of the first piston.
8 and are pivotally engaged by pins 19 and 20.

The cross-shaped claws 14 and 14' connected to the output shaft 9 of the first piston move the output shaft 9 of the first piston forward (
The bending angle of the link 17 is increased or decreased by movement (rightward in FIG. 1) or backward (leftward in FIG. 1) to drive the link 17 in the closing direction or opening direction, and the cross connected to the output shaft 10 of the second piston. The claws 15 and 15' in the other direction move the output shaft 10 of the second piston backward (leftward in FIG. 1) or forward (leftward in FIG. 1).
By moving (rightward in the figure), the bending angle of the link 18 decreases or increases, so that it is driven in the closing or opening direction in the same way as the other pawl 14, 14'.

21 and 22 are restoring springs that always urge the first piston 7 and the second piston 8 in the approaching direction; 23 is a pneumatic chamber formed on the opposing surfaces of both the first and second pistons 7.8; 24.2
5.26 is the air vent hole provided in the cylinder body 2 and rear cover 5, 27.28.29 is the airtight O-ring provided in each sliding part, 30 is the air supply port, and 31 is the work that went through the work. This is a hole for securing a nail.

The pneumatic internal clamp type differential four-jaw chuck 1 described above is attached to a robot hand, etc., and each paper is 14.14', 15°15'.
A working claw suitable for the purpose of work is screwed into the screw hole 31, and an air hose is connected to the air supply port 30 of the cylinder body 2. When pressurized air is supplied to the air supply port 30 through the air hose, the air enters the pneumatic chamber 23 formed on the opposing surfaces of the first and second pistons 7.8 and expands it.
Both the first and second pistons 7.8 are separated from each other by compressing the spring 21.22, and accordingly, the output shaft 9 of the first piston advances, the output shaft 10 of the second piston retreats, and the first piston A cross-shaped one-way pawl 14.14' engaged with the output shaft 9 of the second piston by a link 17 and the output shaft 10 of the second piston.
A cross-shaped pawl 15.15' engaged with a link 18
are both driven in the cylinder axial direction. As a result of this drive, if any of the L claws of the oath papers 14, 14' and 15, 15', for example, the working claws of the opposing claws 14, come into contact with the object to be held, the object will be moved as the working claws of the claws 14 move. The first piston 7 is moved in the direction of the opposing claws 14', and when the working claws of both opposing claws 14, 14' come into contact with the object to be held, the first piston 7 that drives the claws 14, 14' is stopped, and then the second piston 7 is moved. The piston 7 differentially continues to move backward, and the second piston 7 drives one of the other pawls 15 and 15', for example, the opposite pawl 1.
When the working claws 15 and 15' contact the object to be held, the object is moved toward the opposing claw 15' along with the movement of the working claws 15, and the working claws of both opposing claws 15 and 15' contact the object. The second piston 8 is also stopped when they touch each other, and both pistons 7 are now stopped.
．． 8 are subjected to equal air pressures that act against each other, and even if the object to be held has an irregular shape, the paper 14.14'
, 15° and 15', and are automatically centered and gripped.

When releasing the gripped object, the pressure in the pneumatic chamber 23 is released, and the eleventh second piston 7.8 returns to its original approach position with the restoring force of the spring 21.22, and accordingly the claw 14.1
4', 15, and 15' are simultaneously opened in the direction opposite to the center of the cylinder, and the gripped object is released.

In contrast to the basic differential four-jaw chuck 1 explained above, the first
The interlocking cross-shaped claws 14.14' and 15.15' of the piston 7 and the second piston 8 are connected to the first piston 7.
A differential four-jaw chuck of external clamping type is obtained by linking so that both are driven in a direction opposite to the center of the piston by the forward movement of the second piston and the backward movement of the second piston, and
By similarly moving the first piston 7 and the second piston 8, the claws in one direction of the cross are driven toward the center of the piston, and the claws in the other direction of the cross are driven in a direction away from the center of the piston. It is possible to obtain a differential four-jaw chuck with one side tightening and one externally tightening type, and these conversions are also possible by simply replacing the ring.

In addition, as another modification, 1. The initial position of the second piston 7.8 is set to a separated state, and pressure air is introduced to both sides of both pistons 7.8, so that the first and second pistons 7.8
It is also possible to configure a differential four-jaw chuck that performs the same action as described above by driving the two in the approach direction.

Furthermore, the driving of the first and second pistons 7.8 is not limited to pneumatic pressure.
Of course, hydraulic or manual means are also possible.

FIG. 3 shows an embodiment of a hydraulic internal clamp type differential four-jaw chuck, and this differential four-jaw chuck 32 communicates with a hydraulic chamber 33 between the first and second pistons 7.8. Hydraulic inlet 3
4, and a hydraulic outlet 36 communicating with the hydraulic chambers 35.35 on both the front and rear sides of both the first and second pistons 7.8 is a directional control valve 37.
It is connected to the hydraulic pressure generator 38 via. In this chuck 32, the pneumatic restoring spring 21.22
is not necessary, and O-rings 39 and 40 are added.

When the directional control valve 38 is placed in the normal position I, the output circuit 38a of the hydraulic pressure generator 38 is connected to the hydraulic inlet 34 of the chuck 32.
and the return circuit 38b of the hydraulic pressure generator 38.
is connected to the hydraulic outlet 36.36 of the chuck 32, and the hydraulic oil flows into the hydraulic chamber 33 between the two pistons 7.8.
3 is enlarged, and the hydraulic oil contained in the hydraulic chambers 35.35 on both the front and rear sides of both pistons 7.8 is transferred to the hydraulic pressure generator 38.
The pawls 14.14'15, 15' interlocked with each output shaft 9.10 of both pistons 7.8 are driven in the closing direction.

When releasing the gripped object, by switching the directional control valve 37 to the reverse position ■, the oil pressure on both sides of the reduced pistons 7.8 is reduced to 35.35.
Both pistons 7, which had expanded as hydraulic oil flowed into the
．． The hydraulic oil in the hydraulic chamber 33 between 8 and 8 is returned to the return circuit 38b of the hydraulic pressure generator 38, and both pistons 7.8 return to their original close positions, and the claws 14.14' and 15.15' open to grasp the object. will be released.

FIG. 4 shows an embodiment of a manual internal tightening type differential four-jaw chuck using a drive screw. 42
The threaded portion 42b of the drive screw 42 is inserted into the internal threaded hole 7a provided in the first piston 7, and the opposing surfaces of the first piston 7 and the second piston 8 are A screw head 42c of a drive screw 42 is interposed therebetween, and a plurality of rotation holes 42d arranged in the circumferential direction are provided on the outer periphery of the screw head 42c. To operate this differential four-jaw chuck 41, the bar 44 is inserted into the bar hole 42d of the screw head 42c through the operation hole 43, which is opened in the cylinder body 2 with a central angle of about 90 degrees, and the bar 44 is successively inserted into the next bar. Rotation hole 4
2d and rotate the drive screw 42 to screw the female threaded hole 42d of the first piston 7 forward and backward, thereby opening the pawl 1.
4°14' and 15.15' can be opened and closed differentially.

In the figure, 45 is a bearing that reduces friction between the spring head 42c and the surface of the second piston 8, and 21 and 22 are similar to the embodiment shown in FIG. It is a spring that biases the

The hydraulic and manual differential four-jaw chucks are not limited to the internal clamping type, but can of course be changed to an external clamping type, one internal clamping and the other external clamping type, by changing the operating direction of the link.

In addition, the method of interlocking the first and second pistons with the claws in two cross directions is not limited to links, and various changes such as a cam system using slopes are possible, and other specific structures, shapes,
Various changes such as materials are included in the present invention as long as they do not contradict the technical idea of the present invention.

〔Effect of the invention〕

As explained above, the differential four-jaw chuck of the present invention takes out the respective output shafts of the two pistons inserted in series in the cylinder body in the same direction on a common axis, and By engaging each pair of opposing pawls in two directions of the cross and driving the two pistons in opposite directions, the pair of opposing pawls in each direction of the cross come into contact with the object to be held and are stopped. Therefore, no matter how oddly shaped the object is, it can be grasped reliably and centripetally without damaging the object by effectively using the four claws without adjusting the position of the claws, and depending on the shape of the object, It is possible to change to various gripping methods such as internal tightening, external tightening, one direction internal tightening and the other direction external tightening, etc. Furthermore, the drive method can be selected from pneumatic, hydraulic, manual, etc. depending on the factory equipment. In addition, it has features such as a simple structure and can be provided at low cost, and it greatly contributes to improving the precision and productivity of production lines.The range of applications is also assembly robots, chucks of various machine tools, and high-temperature furnaces. It has a wide range of applications, including handling in adverse environments such as liquids and liquids, as well as applications such as swivel joints and swivel cams.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and Fig. 1 is a developed cross-sectional view along a 90-degree fold line passing through the jaws in two cross directions of a pneumatic internal clamping type differential four-jaw chuck, and Fig. 2 is a front view of the same chuck. Figure, 3rd
The figure is an exploded cross-sectional view similar to Figure 1 of a hydraulic internal clamp type differential four-jaw chuck, and Figure 4 is an exploded cross-sectional view similar to Figure 1 of a manual internal clamp type differential four-jaw chuck. be. l...Pneumatic internal clamping type differential four-jaw chuck, 7...
First piston, 8... Second piston, 9... Output shaft of the first piston, lO... Output shaft of the second piston, 1
4, 14'... A pair of opposite claws in one direction of the cross, 15.1
5'... A pair of opposing jaws in the other direction of the cross, 32... Hydraulic internal clamping type differential four-jaw chuck, 41... Manual internal clamping type differential four-jaw chuck.

Claims (1)

[Scope of Claims] 1. The output shafts of two pistons inserted in series in the cylinder body are taken out in the same direction on a common axis, and by engaging a pair of opposing claws and driving the two pistons in opposite directions, the pair of opposing claws in each direction of the cross are differentially moved until they respectively abut the object to be held and are stopped; A differential four-jaw chuck characterized by being configured to grip an object. 2. The differential four-jaw chuck according to claim 1, wherein the means for driving the two pistons in mutually opposite directions is based on air pressure. 3. The differential four-jaw chuck according to claim 1, wherein the means for driving the two pistons in mutually opposite directions is hydraulic. 4. The differential four-jaw chuck according to claim 1, wherein the means for driving the two pistons in opposite directions is a screw interposed between the cylinders and driving the cylinders apart. 5. According to any one of claims 1 to 4, the claws in the two cross directions are linked to the movement of the two pistons in mutually opposite directions so as to tighten toward the center of the cylinder. differential four-jaw chuck. 6. According to any one of claims 1 to 4, the claws in two cross directions are linked to the movement of the two pistons in mutually opposite directions so as to tighten in a direction opposite to the center of the cylinder. The differential four-jaw chuck described. 7. The claws in the two directions of the cross are tightened so that the pair of claws facing each other in one direction of the cross tightens toward the center of the cylinder, and the pair of claws facing each other in the other direction of the cross tightens toward the opposite center of the cylinder. The differential four-jaw chuck according to any one of claims 1 to 4, characterized in that the four-jaw differential chuck is linked to movement in mutually opposite directions.