JPH035367Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a chuck pawl attachment device for a chuck for a lathe, which allows the chuck pawl to be attached and detached in an extremely short time.

[Conventional technology]

In the case of high-mix, low-volume production, it is necessary to replace the chuck jaws in small lots in order to accommodate changes in the size and shape of the workpiece during turning.

For this reason, various chuck pawl replacement devices have been proposed in the past.

For example, a device disclosed in Japanese Patent Application Laid-Open No. 60-99505 fixes a pin having a circular or oval cross section with a large-diameter head on the front surface of a chuck pawl mounting member, and the pin has a circular or oval cross section on the rear surface of the chuck pawl. An elliptical recess into which the large-diameter head of the pin loosely fits is provided, an undercut is provided inside one end of the recess, and the large-diameter head of the pin fitted into the recess is engaged with the undercut. This prevents it from falling out.

Furthermore, the device disclosed in Japanese Patent Application Laid-open No. 57-75707 has a plurality of engaging protrusions on both front sides of a radial groove provided on the front surface of the chuck body, and the above-mentioned engaging protrusions are provided on both rear sides of the chuck pawl. A plurality of outward engaging protrusions that engage with the mating protrusions are provided.

[Problem that the invention attempts to solve]

In the conventional device as described above, the large-diameter head of one pin provided on the chuck mounting member is fitted into one recess of the chuck pawl, and the chuck is attached by partially engaging the undercut with the large-diameter head. Since the chuck is fixed, there are very few engaging parts and the chuck is unstable, causing problems when subjected to large loads.

In addition, in the case where engaging protrusions are provided on both front sides of a groove provided on the front surface of the chuck body, chips and other foreign matter easily enter the groove, and it takes time and effort to remove the foreign matter that has entered the groove.

Furthermore, since the outward engaging protrusions are provided on both sides of the rear part of the chuck pawl, there is a problem in that the reaction force when tightening the workpiece is concentrated on the attachment part of the engaging protrusion, which tends to cause breakage.

[Means for solving problems]

In order to solve the above problems, this invention is a lathe chuck which has a plurality of chuck pawls that are opened and closed by a chuck pawl drive mechanism on the front part of the chuck body, and a chuck pawl mounting base that is opened and closed by the chuck pawl drive mechanism. is provided protruding from the front surface of the chuck body, a coupling block is provided at the front of the chuck pawl mounting base, and a recess into which the coupling block removably fits is provided on the rear surface of the chuck pawl. A plurality of engaging protrusions are provided at both front parts of the block and at both rear sides of the recess of the chuck pawl, and at the end of the chuck pawl mounting base, the connecting block fits into the recess of the chuck pawl and the recess is formed. A stopper is provided at the bottom of the recess of the chuck pawl to receive the end of the chuck pawl under the condition that the engaging protrusions on both rear sides of the connecting block are engaged with the engaging protrusions on both front sides of the coupling block.
A fixing means consisting of a ball is provided which engages with the recess of the coupling block by the elasticity of a spring under the condition that the chuck pawl is received by the stopper of the coupling block.

[Effect]

Since this invention has the above-mentioned structure, when attaching the chuck pawl to the chuck pawl mounting base provided on the front surface of the chuck body, there is a gap between the plurality of engaging protrusions on both sides of the connecting block fixed to the chuck pawl mounting base. Fit the coupling block into the recess so that the engaging protrusions on both sides of the chuck claw fit into the recess, and then insert the chuck claw against the coupling block with the coupling block and the chuck claw completely fitted into the recess. When the engaging protrusion is shifted by one pitch, the engaging protrusion of the connecting block and the chuck pawl are engaged and the two are connected, and at the same time, the end of the chuck pawl is received by the stopper at the end of the connecting block.

Further, at this time, the ball of the fixing means provided in the recess of the chuck pawl is coupled to the recess of the coupling block by the action of the spring, thereby preventing the chuck pawl from coming off. If you want to separate the two, you can easily do it by reversing the above procedure.

[Embodiment] In the embodiment shown in the drawings, reference numeral 1 denotes a chuck main body which is fixed concentrically to the tip of the main shaft of a lathe (not shown), and a rear member 2 and a front member 3 are separated by a partition plate 4, and a bolt is connected to the chuck body. 5, and a hydraulic cylinder 6 is formed inside the rear member 2.

The piston 7 in the cylinder 6 moves forward and backward as hydraulic oil flows back and forth within the cylinder 6, has a spring 8 that pushes the piston 7 backward, and is prevented from rotating by a rotation prevention pin 9. .

The rod 10 at the front of the piston 7 protrudes forward from the central hole of the rear member 2 while maintaining liquid tightness, and the small diameter portion at the rear of the chuck pawl driving actuator 12 is fixed to its front end with a bolt.

The actuator 12 is located in the space 1 within the front member 3.
4, and the small diameter part at the rear is the partition plate 4.
It passes through the hole and is connected to the rod 10 as described above.

Reference numeral 13 denotes a chuck pawl drive mechanism, which includes the actuator 12, a plurality of eccentric sliding balls 15 rotatably attached to the actuator 12, and a rear part of which is slidably fitted into a hole of each ball 15, and an intermediate It is composed of a plurality of jaw actuators 16 whose parts are swingably mounted on the front wall of the space 14.

In addition, a chuck pawl mounting base 18 is fixed to the tip of each jaw actuator 16, and a work stopper 19 is fixed to the front member 3 facing each of the mounting bases 18, and the inner surface of each stopper is fixed. The workpiece positioning block 20 is fixed to.

A coupling block 22 is fixed to the front part of the mounting base 18 with bolts 23.

The connecting block 22 has a rectangular shape, and a plurality of engaging protrusions 24 are integrally formed at a constant pitch on both front sides thereof.

26 is a chuck claw, and has a carbide insert 27 on its gripping surface. Further, a recess 28 into which the coupling block 22 fits is provided on the rear surface of the chuck pawl 26, and a plurality of engagement protrusions that engage with the engagement protrusions 24 of the coupling block 22 are provided at both rear sides of the recess 28. The portions 29 are integrally formed with a constant pitch.

Furthermore, a stopper 31 is integrally provided at the end of the chuck pawl mount 18 to receive the end of the chuck pawl 26 at the coupling position, and a fixing means 32 is provided on the chuck pawl 26.

As shown in FIG. 3, this fixing means 32 has a ball 35 pushed outward by a push spring 34 in a recess provided at a predetermined depth from the inner end of a bolt 33 that is screwed into a screw hole provided in the chuck pawl 26. The ball 3 is attached to the front surface of the connecting block 22 when the block 22 and the chuck pawl 26 are properly connected.
A spherical recess 36 into which 5 is fitted is provided.

To connect the chuck pawl 26 to the connecting block 22, the engaging protrusion 29 at the lowest end of the chuck pawl 26 must be placed directly above the connecting protrusion 24 at the lowest end on the block 22 shown in FIG. Then, each engaging protrusion 29 of the chuck pawl 26 is inserted between each engaging protrusion 24 of the block 22, and the block 22 and the recess 28 of the chuck pawl 26 are fitted into each other.

In this way, when the front surface of the block 22 comes into contact with the bottom surface of the recess 28, the engagement protrusion 24 has reached the inside of the engagement protrusion 29, so if the chuck pawl 26 is slid in this state until it hits the stopper 31, each The block 22 and the chuck pawl 26 are connected by overlapping the engaging protrusion 24.

Also, at this time, the ball 35 of the fixing means 32 prevents the recess 36 of the block 22 from moving.

Furthermore, by moving the chuck pawl 26 that has been connected to the block 22 as described above in the opposite direction to the direction in which it was connected, by applying a slight force, the ball 35 can be moved into the recess 3.
Since it can be removed from 6, it can be easily removed by reversing the operation when connecting.

Next, to explain the chuck action based on FIG. 1, first, the hydraulic circuit of the hydraulic cylinder 6 is set to the open side, hydraulic oil is poured into the rear chamber, the hydraulic oil is drained from the front chamber, and the actuator 12 is moved forward together with the piston 7. Then, each jaw actuator 16 is rotated to open each chuck pawl 26.

Next, after a workpiece (not shown) is inserted into each chuck pawl 26, the hydraulic circuit of the cylinder 6 is switched to the gripping side and the actuator 12 is moved backward, thereby gripping the workpiece with each chuck pawl 26.

In this state, the reaction force in the radial direction applied to the chuck pawl 26 by gripping the workpiece is mainly received by the stopper 31, and the rotational moment applied to the chuck pawl 26 is supported by the contact portions of the plurality of engagement protrusions 24 and 29. Ru.

〔effect〕

As mentioned above, in this invention, the chuck pawls are detachably attached to a plurality of chuck pawl mounting bases that are opened and closed by the chuck drive mechanism provided on the chuck body, via a connecting block. A chuck pawl mount protrudes from the front of the main body, and engaging protrusions are provided on both sides of the front of the connecting block fixed to the front of the protruding chuck pawl mount, so chips etc. that adhere to these parts can be removed. Can be easily removed.

Furthermore, since the chuck claw is provided with a recess, even if foreign matter such as chips gets into the recess, the chips can be easily removed by holding the chuck claw and turning the recess downward.

Further, since the engaging protrusions are provided on both sides of the recess of the chuck pawl, there is little risk of the engaging protrusions being damaged by reaction force during tightening.

Further, the chuck pawl is provided with a fixing means having a ball pressed by a spring, and the ball automatically moves into the recess of the connecting block under the condition that the chuck pawl connected to the connecting block is received by the stopper at the end of the connecting block. Since they engage, the chuck can be fixed very easily and reliably.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional side view of a chuck for a lathe implementing this invention, Fig. 2 is an enlarged front view of the same chuck pawl attachment part as above, Fig. 3 is a cross-sectional bottom view taken along line A-A in Fig. 2, and Fig. 4 The figure is an exploded perspective view of the same part. DESCRIPTION OF SYMBOLS 1...Chuck body, 13...Chuck pawl drive mechanism, 18...Chuck pawl mounting base, 22...Connecting block, 24, 29...Engaging protrusion, 26...Chuck pawl, 28...Recess, 31...Stoppa, 3
2... Fixing means, 35... Ball, 36... Spherical recess.

Claims (1)

[Scope of utility model registration request] In a lathe chuck having a plurality of chuck pawls which are opened and closed by a chuck pawl drive mechanism on the front part of the chuck body, a chuck pawl mounting base which is opened and closed by the drive mechanism is provided protruding from the front of the chuck body, and this A connecting block is provided at the front of the chuck pawl mounting base, and a recess into which the connecting block removably fits is provided at the rear surface of the chuck pawl, so that the front portions of both sides of the connecting block and the recess of the chuck pawl are connected to each other. A plurality of engaging protrusions are provided at the rear of both sides of the chuck pawl, and the connecting block fits into the recess of the chuck pawl, and the engaging protrusions at the rear of both sides of the recess are provided at the end of the chuck pawl mounting base. A stopper is provided to receive the end of the chuck pawl under the condition that the chuck pawl is engaged with the connecting projections on both front sides of the connecting block, and furthermore, a stopper is provided at the bottom of the recess of the chuck pawl so that the chuck pawl is received by the stopper of the connecting block. A chuck pawl attachment device for a chuck for a lathe, characterized in that it is provided with a fixing means consisting of a ball that engages in a recessed portion of a connecting block by the elasticity of a spring.