JPH088005Y2 - Workpiece tightening mechanism in spawn chuck - Google Patents

Description

[Detailed Description of the Invention] "Industrial field of application" The present invention relates to a three-jaw or four-jaw spawn chuck in which a cylinder is built into a chuck, and each claw is made to follow (float) the outer circumference of a work (fastener). Thus, the present invention relates to a work tightening mechanism in a spawn chuck that securely and firmly holds, for example, the tightening of a shaft work that is eccentric to the center.

"Prior Art" A spawn chuck provided with a cylinder inside the chuck and opening and closing the claws by advancing and retracting a piston inserted into the cylinder has already been put into practical use.

FIG. 6 is a drawing showing an example thereof. As shown in the drawing, a piston c is inserted into a cylinder chamber b formed in a case main body a so as to be able to move back and forth, and the piston c has an elastic force of a spring d. Is provided so as to always be urged in the backward direction (the direction in which the claws described later are tightened), and the crank pressing washer f is fixed to the head of the piston c by the annular recess e, and the annular recess One end of a crank h that horizontally moves each claw g is engaged with e. More specifically, each crank h is formed to have an L-shape, is rotatably supported by a support shaft i, and one end thereof is engaged with the annular recess e as described above. On the other hand, the other end is engaged with the bottom part of the jaw j that fixes the claw g. The piston c is pushed out by pressing air into the rear surface of the piston c from the supply hole k communicating with the cylinder chamber b, and each crank h that engages one end with the annular recess e of the piston c rotates. Then, the claws g are opened so that each claw g can be expanded outward along the radial direction centered on the center 1 via the jaw j that engages with the other end. When the work is set in the center 1 in this state and air is removed from the cylinder chamber d through the supply hole k, the piston c is pushed back by the elastic force of the spring d, and each crank h is rotated in the opposite direction. Each claw g is provided so that the work can be clamped.

[Problems to be solved by the invention] As described above, the piston c is retracted by the elastic force of the spring d, and each claw g is rotated by each crank h that rotates in conjunction with the retraction of the piston c. In the spawn chuck of the conventional structure provided to move the claws in the tightening direction, the movement amount of each claw g is the same with the center 1 as the center.
When the center engraved on the work deviates from the center of the work and eccentricity occurs, when the work is set on the center 1 and tightened, as shown in FIG. There is a problem in that one claw g comes into contact with the outermost position of the work farthest from the position at the same time as the other claw g also stops at that position, and the strong clamping action of the work by all the claws g cannot be obtained. are doing.

The present invention attempts to solve the above problems, and the problem of the present invention is to fix each claw when tightening a work in which the center and center of the work are eccentric. The point is that the outer circumference of the work is pressed against the work piece with a uniform force so that the work can be securely tightened.

That is, according to the present invention, one end of each crank, which is inserted into the annular recess of the piston by a plurality of pins that are interlocked via hydraulic pressure, is sandwiched from the upper and lower end surfaces of the crank, and the forward and backward movement of each pin causes the crank to move. The feature is that each claw can be made to follow the outer circumference of the work by changing the amount of rotation according to the eccentricity of the work, and the concrete means and action are as follows. Is.

"Means for Solving the Problem" A pair of upper and lower crank press washers are provided facing each other with an annular recess in the head of the piston, and each crank press washer is formed with a plurality of cylinder cylinders. The cylinder cylinders communicate with each other through an oil chamber provided at the back of the cylinder cylinders, and piston pins that interlock with each other via hydraulic pressure are inserted into the cylinder cylinders so that the piston pins can advance and retreat. One feature is that the upper and lower end faces of one end of one end of the horizontal arm of the crank inserted into the recess are held against each other, and the top and bottom end faces of the one end of the horizontal arm of the crank are held by the tip ends of the piston pins. And the structure.

"Operation" When setting a work with an eccentric center and retracting the piston to tighten the work, the first claw was actuated when the first claw hits the outermost position of the work farthest from the center. The rotation of the crank stops, but the piston pin on the upper side, which is stopped at one end of the crank, is pushed into the cylinder cylinder, and the piston is retracted further. The other crank, which is pushed out in the opposite direction by the piston pin and is stopped by the piston pin, can be further rotated so that all the pawls interlocked with the crank can be stopped on the outer periphery of the work.

Further, each piston pin on the lower side advances and retreats in accordance with each crank that rotates unevenly as described above, and is constantly urged against the lower end surface of the crank to prevent rattling of the crank.

[Examples] Specific examples of the present invention will be described below with reference to the accompanying drawings.

In the drawings, 1 is a guide ring, 2 is a case body rotatably supported by the guide ring 1 through a pair of upper and lower bearings 3, 3, and 4a and 4b are the top and bottom portions of the case body 2, respectively. A lid plate and a bottom plate fixed to each other via bolts 5a ..., 5b ... so as to be closed, and a piston 6 formed in a substantially inverted T-shape which is fitted in a cylinder chamber 7 so as to be able to move back and forth. A plurality of pins 9 ... Penetrating the cylinder chamber 7 are inserted into the large diameter portion 8 of the piston 6, and each pin 9 has an upper end surface of the large diameter portion 8 and a top wall of the cylinder chamber 7. A spring 10 is provided over the space, and the piston 6 is provided so as to be constantly biased in the backward direction by the elastic force of the spring 10. Further, the side wall of the guide ring 1 has an air supply hole.
11 is opened, an annular groove 12 is engraved on the outer peripheral wall surface of the case body 2 corresponding to the supply hole 11, and the annular groove 12 is also formed.
Is provided so as to communicate with the cylinder chamber 7 through the passage 13 and supply air to the rear surface of the piston 6. On the other hand, the head of the piston 6 has an annular recess 14, and crank pressing washers 15a and 15b are provided at the upper and lower positions in a confronting manner. That is, the upper crank clamp washer 15
The a is fixed to the small end portion of the piston 6 via a bolt 16, while the crank pressing washer 15b on the upper side is fitted to the small diameter portion 17 of the piston 6. Same crank press washer
By mounting 15a and 15b, multiple cylinder cylinders 18
... are provided, and each cylinder tubular portion 18 ... is communicated with each other through an oil chamber 19 formed in the inner part thereof, and each cylinder tubular portion 18 ... is provided with a piston pin 20 ...
Is inserted so as to be able to move forward and backward, and the tip end portion of the piston pin 20 ... Is projected toward the annular recess 14 in an opposed manner.
Further, a plurality of crank chambers 21 ...
Each of the crank chambers 21 has a horizontal arm 22a and a vertical arm 22b, and the crank 22 is formed into an L-shape.
It is pivotally supported via 3. And each crank 22
The end portion of the horizontal arm 22a is fitted into the annular recess 14, and the upper and lower end surfaces of the horizontal arm 22a project from the crank pressing washers 15a and 15b in the opposite directions, respectively.
..Two ends of 20 ... are stopped against each other, and horizontal arm
The tip portion of 22a is provided so as to be held by the pistons 20, 20, 20, 20 in a sandwiched state. Further, each of the crank chambers 21 is provided with a jaw 25 which is slidable in the radial direction around the center 24, and the bottom of each jaw 25 has a tip portion of the vertical arm 22b of the crank 22. While the claws are engaged with each other, the claws 26 are fixed to the upper surface of each jaw 25 through the bolts 27.

 Next, the operation will be described.

As shown in FIG. 1, when the piston 6 is pushed back to the retracted position by the elastic force of the spring 10 and the claws 26 ... The air is pressed into the rear surface of the piston 6 in the cylinder chamber 7 through the annular groove 12 and the passage 13, and the piston 6 is pushed out against the elastic force of the spring 10. When the piston 6 is pushed out in this way, the cranks 22 ..., which support the tip of the horizontal arm 22a in the annular recess 14, are rotated, and the jaw 25 that engages with the tip of the vertical arm 22b is moved. A state in which each pawl 26 is opened by sliding it outward can be obtained. Then, in this state, the work can be attached and detached. In the case of tightening a shafted work with a center, the center of the work, which is pre-engraved with a center drill or the like at the center of the work, is engaged with the center 24 of the main chuck. The center of the work side, which is engraved with a center drill, etc., is rarely engraved exactly in the center of the work, and slightly (0.1 mm
A deviation of about 0.5 mm is common. Therefore, when the same work is set on the center 24, the dimension from the center 24 to the peripheral edge of the work as shown in FIG.
L1 and L2 will be set in different states. When the air is released in this state, the piston 6 is pushed back by the elastic force of the spring 10 and each crank 22
Rotates in the opposite direction to the above, and each claw 26
.. is moved toward the tightening direction, that is, toward the center 24, and the work is tightened by the claws 26. At this time, of the claws 26 .. When the first claw 26 strikes against the peripheral edge of the distant work, the rotation of the crank 22 that operates the claw 26 stops, and at the same time, it strikes against the tip of the horizontal arm 22a of the crank 22. Crank foot washer 15a on the upper side
Piston pin 20 moves backward and the piston 6 is further pushed back, and other piston pins 20 ... that are interlocked with each other via the hydraulic pressure pushed by the backward movement of the piston pin 20 are pushed out, and the pushed piston pin 20 is pushed out. The cranks 22 ... other than the above are further rotated by 20 ..., and all the claws 26 ... are evenly hit against the work, and the claws 26 ...
Gives a strong work tightening condition. or,
Piston pin 20 of the lower crank clamp washer 15b
Is moved in accordance with the horizontal arm 22a of each crank 22 which rotates unevenly as described above, and the backlash of the horizontal arm 22a is always prevented. As described above, the horizontal arm 22a has its upper and lower end surfaces projecting (upward) from the upper crank pressing washer 15a (upward).
..Tips and lower crank washer 15b
It is configured to be held by the tip of the more protruding (lower) piston pin 20 .... Then, as a result, for example, the first arm is attached to one of the horizontal arms 22a.
Even if a downward impact is applied in the figure (the same impact is applied to the claw 26 from the center direction), the lower piston pin in the figure
It is received by 20 ..., and conversely, even if an upward impact is applied in the figure (the same impact from the anti-center direction to the claw 26), it is received by the upper piston pin 20 ... in the figure. Therefore, a shock from any direction of the so-called horizontal arm 22a (claw 26) can be effectively dealt with by the action of the pair of piston pins 20 ... The effect of being able to secure a strong fixed state of the work by.

In the present invention, since the crank press washers 15a and 15b are detachably installed, when the crank 22 is not required to be changed in the amount of rotation as described above, a normal piston pin is not provided. It can be replaced with a cylindrical washer.

[Advantage of the Invention] As described above, the present invention has an annular recess in the head of the piston, and a pair of upper and lower crank press washers are provided to face each other. A plurality of piston pins that project forward and backward from both crank press washers are clamped in the arm in a clamped state, and the forward and backward movements of the piston pins in each washer are interlocked via hydraulic pressure. It is possible to change the amount of rotation of each crank according to the eccentric state of the center provided at the center, and it is possible to evenly abut the claws against the work and securely tighten the work.

Particularly, in the present invention, the upper and lower end surfaces of one end of the horizontal arm of each crank are held by the tip end portions of the piston pins provided in a confronting shape. Therefore, for example, even if a downward impact is applied to one of the horizontal arms in FIG. 1 (the impact of the claw is the same), it is received by the lower piston pin in the same figure, and conversely in the upward direction in the same figure. Even if a shock is applied to it (the same as the impact of the claw), it is received by the upper piston pin in the same figure, and the impact of the so-called horizontal arm and the claw from both directions causes The function effectively responds to this, and there is an effect that a firm fixed state of the work by the crank and the claw can be secured. Further, due to this effect, even if there is some impact on each crank or each claw, each crank or each claw does not deviate, and, for example, there is no problem such as detachment of the chucked work. Furthermore, the crank does not freely rotate due to the impact, and the free state of the piston pin that restricts the horizontal arm of the crank is avoided, and, for example, a biased flow of oil in the oil chamber with respect to the piston pin in a certain free state occurs. Since the other piston pins do not move up and down without permission, the reliability of the work clamping accuracy by the crank is achieved.

[Brief description of drawings]

1 to 5 are drawings showing an embodiment of the present invention, wherein FIG. 1 is a sectional view taken along the line AA in FIG. 2, FIG. 2 is a plan view, and FIG. 3 is an upper part. A bottom view of the side crank press washer, FIGS. 4 and 5 show the operating state, FIG. 4 is a sectional view taken along the line BB in FIG. 5, and FIG. 5 is a plan view. FIG. 6 is a side sectional view showing a conventional example, and FIG. 7 is an explanatory view of its working state. 1 ... Guide ring, 2 ... Case body, 3 ... Bearing, 4a ... Lid plate, 4b ... Bottom plate, 5a, 5b ... Bolt, 6
...... Piston, 7 ...... Cylinder chamber, 8 ...... Large diameter part, 9
...... Pin, 10 ...... Spring, 11 ...... Supply hole, 12 ...... A annular groove,
13 ... passage, 14 ... annular recess, 15a, 15b ... crank holding washer, 16 ... bolt, 17 ... small diameter part, 18 ... cylinder cylinder part, 19 ... oil chamber, 20 ... piston pin ,twenty one…
… Crank chamber, 22 …… Crank, 22a …… Horizontal arm, 2
2b ... Vertical arm, 23 ... Spindle, 24 ... Center, 25 ...
… Joe, 26 …… claws, 27 …… bolts.

Claims (1)

[Scope of utility model registration request] 1. A cylinder chamber is provided in a case main body, and a piston formed in an inverted T-shape is inserted in the cylinder chamber so as to be able to move forward and backward, and the piston is always attached in a backward direction through elastic force of a spring. The cylinder chamber is located on the back side of the piston to communicate with the air press-in passage, while an annular recess is formed in the head of the piston. One end of each of a plurality of L-shaped cranks that are movably supported is fitted into each of the cranks, and the other end of each crank is attached to the lower end surfaces of a plurality of jaws that slide in a radial direction around a center. In the spawn chucks that are engaged with each other and fixedly attach the pawls to the upper end surface of each jaw, place a pair of upper and lower crank press washers facing each other in the vertical position with the annular recess in between. Provided and each crank presser A plurality of cylinder cylinders are formed in the washer, and each cylinder cylinder is made to communicate with each other through an oil chamber provided at the back of the cylinder, and each cylinder cylinder has a piston pin that is interlocked via hydraulic pressure. The piston pin can be inserted and moved back and forth, and the tip end of each piston pin is abutted against the upper and lower end faces of one end of the same horizontal arm of the same crank that is inserted and inserted into the annular recess, and the piston pins A workpiece tightening mechanism for a spawn chuck, characterized in that the upper and lower end surfaces of one end of the same horizontal arm of the same crank are held by the tip portion.