JP3446416B2 - Finger chuck - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a finger chuck suitable for turning aluminum wheels and the like, and more particularly to a finger chuck of a type in which a large number of clamp arms are opened and closed by a plurality of spiders.

[0002]

2. Description of the Related Art Conventionally, a finger chuck has been known in which a large number of clamp arms are opened and closed by a single spider. According to this structure, when the outer peripheral portion of the work is uneven in thickness, There was a possibility that the gripping forces of the different. Japanese Unexamined Patent Publication No. 7-68405 discloses a technique in which elastic bodies are respectively interposed between six clamp arms and one spider to make the gripping force uniform. Therefore, there is a problem that the number of parts and the number of assembling steps increase.

Therefore, conventionally, as shown in FIG. 8, a finger chuck using two spiders has been proposed. Here, two spiders 52 and 53 are juxtaposed in the chuck body 51 side by side in the front-rear direction, and three clamp arms 54 are connected to the outer peripheral portions of the spiders 52 and 53, respectively. The front spider 52 is driven by a piston of a rotary cylinder (not shown) via an inner draw member 56, and the rear spider 53 is driven by another piston of the rotary cylinder via an outer draw member 55. Has become.

[0004]

However, according to this finger chuck, since the two spiders 52 and 53 are driven through the respective draw members 56 and 55, the number of parts of the drive system is increased. However, it is necessary to provide clearance for the operating stroke so that the spiders 52, 53 do not interfere with each other, the overall length of the chuck becomes longer, the amount of overhang from the spindle mounting surface increases, and the rigidity of the chuck decreases. There was a problem to do. In addition, since the drive systems of the spiders 52 and 53 are different, in the case of a finger chuck provided with a centering claw, a complicated and expensive rotary cylinder equipped with three pistons as drive means is installed on the spindle side. There is also a problem that the number of assembling and disassembling steps at the time of attaching and detaching the chuck is increased accordingly.

Therefore, an object of the present invention is to provide a finger chuck that can reduce the number of parts of the drive system, reduce the overall length of the chuck, use a drive means having a simple structure, and reduce the number of steps for attaching and detaching the chuck. To provide.

[0006]

In order to solve the above-mentioned problems, the finger chuck according to the invention of claim 1 has two front and rear spiders arranged side by side inside a chuck body, and each spider has a plurality of clamps. connecting the arms, the center portion of the chuck body movable a single draw member extending through the respective spider in the axial direction, the draw member
An abutting part with a spherical rear surface is provided at one place on the outer circumference,
Join the first washer to the front of the near front spider and
Join the 2nd washer to the front of the spider and attach it to the front spider.
An accommodation hole for accommodating the second washer is formed, and a contact portion is formed on the first washer.
A through hole is formed with an engaging part that makes spherical contact with the
Then, provide the second washer with a convex part that fits into the through hole, and touch the convex part.
A single draw member that forms an engaging part that makes spherical contact with the contact part
Drive force is transmitted separately to front and rear spiders via each washer
Is configured to be .

A finger chuck according to a second aspect of the present invention comprises an elastic body interposed between at least one spider and a washer joined to the spider.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. As shown in FIGS. 1 and 2, a chuck body 1 of a finger chuck is constructed by assembling a front plate 3 to a front end of a cup-shaped body 2 attached to a spindle (not shown) of a machine tool. A guide sleeve 4 is fixed to the central portion of the rear end of the cup-shaped body 2, and a draw sleeve 5 is inserted inside the guide sleeve 4 so as to be slidable in the chuck axis direction. A draw screw 6 is screwed into the draw sleeve 5, and the sleeve 5 and the screw 6 constitute a single draw member 7. A draw bolt 8 is inserted inside the draw screw 6, and the bolt 8 and the draw sleeve 5 are connected to a pair of pistons of a rotary cylinder (not shown) installed on the spindle side.

Two front and rear spiders 10 and 11 are arranged side by side inside the chuck body 1, and the front end of the draw screw 6 penetrates through the center of these spiders. As shown in FIG. 4 and FIG. 5 in an enlarged manner, one end of the draw screw 6 is provided with a contact portion 12 having a spherical rear surface.
On the rear side of 2, the first washer 13 is joined to the front surface of the front spider 10, and the second washer 14 is joined to the front surface of the rear spider 11. Then, the driving force of the draw member 7 is applied to the front and rear spiders 10, 11 via the washers 13, 14.
Are transmitted separately.

The front surface of the first washer 13 is provided with three engaging portions 13a that make spherical contact with the rear side surface of the abutting portion 12 at three circumferential positions, and the openings are formed between the engaging portions 13a. As shown, three fan-shaped through holes 13b are cut out. Three protrusions 14a that fit into the through holes 13b are provided on the front surface of the second washer 14, and these protrusion end surfaces make spherical contact with the contact portion 12 at a circumferential position different from that of the engaging portion 13a. The engaging portion 14b is formed.

A second washer 1 is provided at the center of the front spider 10.
A housing hole 10a for housing 4 is formed, whereby the first and second washers 13 and 14 are assembled on the draw member 7 in a state of overlapping front and rear. Also, rear spider 1
Three coil springs 15 are interposed as elastic bodies between the first and second washers 14, and in the extended state, a clearance C1 is provided between the front and rear spiders 10 and 11, and the rear spider 11 and the draw sleeve 5 are provided. A clearance C2 is provided between each of the spiders 10, 11 within the angular range allowed by the clearances C1, C2.
Is supported on the draw member 7 so as to be tiltable back and forth.

As shown in FIGS. 1 and 2, six clamp arms 17 are swingably supported by pins 18 on the outer periphery of the front plate 3 in a central V-shaped groove 17a. A grip claw 19 is attached to the front end. Three
The rear ends of the one clamp arm 17 are rotatably connected to the outer periphery of the front spider 10 and the remaining rear ends of the three clamp arms 17 are rotatably connected to the outer periphery of the rear spider 11 by shafts 20, respectively. Each clamp arm 17 is opened and closed via the spiders 10 and 11 as the draw member 7 moves,
In the closed state, the grip claw 19 has a work W such as an aluminum wheel.
Is clamped from the outer peripheral side. A work pedestal 21 is provided on the front surface of the front plate 3 at the same circumferential position as the clamp arm 17. Coil springs 22 and 23 for urging the clamp arm 17 in the opening direction are interposed between the cup-shaped body 2 and the spiders 10 and 11.

As shown in FIGS. 1 and 3, a cylindrical hole 25 is provided in the center of the front plate 3, and a wedge plunger 26 is accommodated in the cylindrical hole 25 so as to be slidable in the chuck axial direction. . Wedge plunger 26
Is connected to the front end of the draw bolt 8 by a bolt 27,
The draw bolt 8 is a guide tube 2 on the back side of the front plate 3
8 will guide you straight ahead. On the front surface of the front plate 3, three guide grooves 29 having a T-shaped cross section (which may have a groove shape or a round cross section) are formed so as to extend radially, and the work W is cored in each guide groove 29. The extending centering claw 30 is slidably fitted. A dust cover 24 is attached to the front plate 3 to prevent chips from entering the cylindrical hole 25 and the wedge plunger 26.

The centering claw 30 has a cross section T that fits in the guide groove 29.
It is composed of a letter-shaped main jaw (master jaw) 31 and a child jaw 32 that engages with the outer peripheral surface of the work W. Prong 31
A wedge portion 31a that meshes with the wedge groove 26a of the wedge plunger 26 is provided at the inner end of the base, and three positioning grooves 31b and four screw holes 31c are provided on the front surface of the outer end portion of the parent pawl 31 in the sliding direction. Are formed at an equal pitch. Child claw 32
A projection 32a is provided on the back surface of the child claw 32a, and the projection 32a is selectively fitted into the positioning groove 31b and the bolt 34 is tightened in the screw hole 31c.
On the other hand, it is adjustably attached at three positions in the sliding direction.
At a position 180 ° away from the centering claw 30, three work seats 36 are provided on the front surface of the outer peripheral portion of the front plate 3.
By selectively tightening the bolts 37 in the plurality of screw holes 38, the bolts 37 can be moved in the radial direction of the chuck 3 at the same pitch as the child claws 32.
Adjustably mounted in position.

When the workpiece W is gripped by the finger chuck constructed as described above, first, one wedge of the rotary cylinder pulls the wedge plunger 26 rearward through the draw bolt 8 to form the wedge groove 26a. Wedge part 3
The master claw 31 of the centering claw 30 is slid inward through the engagement with the la, and the work W is centered by the slave claw 32. In this centered state, the draw member 7 is pulled backward by another piston of the rotary cylinder, and the first and second washers 1
The front and rear spiders 10 and 11 are retracted via 3 and 14, the six clamp arms 17 are simultaneously rotated in the closing direction, and the workpiece W is clamped by the gripping claws 19.

Here, when the thickness of the outer peripheral portion of the work W is uneven, one or both of the spiders 10 and 11 are tilted so that an excessive gripping force does not act locally on the work W. The gripping force of each clamp arm 17 is adjusted.
In this case, since the coil spring 15 is interposed between the rear side spider 11 and the second washer 14, the displacement difference between the spiders 10 and 11 due to the uneven thickness is absorbed, and the clamp arms 17 are absorbed. The gripping force of can be adjusted almost evenly.

Further, according to the finger chuck of this embodiment, since the two spiders 10 and 11 are driven by the single draw member 7, the number of parts of the drive system can be reduced and each spider 10 and 11 can be reduced. By arranging 11 at extremely close positions, the overall length of the chuck can be shortened, the amount of overhang from the spindle mounting surface can be reduced, and the rigidity of the chuck can be improved. Moreover, since the six clamp arms 17 are simultaneously opened and closed by one piston of the rotary cylinder, a simple and inexpensive rotary cylinder including two pistons including the piston for opening and closing the centering pawl 30 is used. Naturally, the number of assembling and disassembling steps for attaching and detaching the chuck is reduced.

Particularly, the engaging portion 14b of the second washer 14 is the first
Since the washer 13 is engaged with the contact portion 12 through the through hole 13b, only one contact portion 12 is required, and the length of the draw member 7 can be shortened. Also, the second washer 14 is the front side spider 1.
Since it is accommodated in the accommodating hole 10a of 0, two washers 1
It is also possible to compactly install 3, 14 in a limited space on the draw member 7 in a superposed state.

6 and 7 show another embodiment of the spider drive mechanism. Here, the through hole 13b is formed in a circular shape in the first washer 13 and the second washer 14 is formed.
A convex portion 14a that fits into the through hole 13b is provided in an annular shape on the front surface of the. Then, the engaging portion 14 at the protruding end of the convex portion 14a
b is in spherical contact with the contact portion 12 at a location radially inward of the engaging portion 13a of the first washer 13. According to this structure, there is an advantage that each of the washers 13 and 14 can be processed in a relatively simple shape. Other configurations and operational effects are similar to those of the above-described embodiment.

The present invention is not limited to the above-described embodiment, and as illustrated below, the configuration and shape of each part may be arbitrarily changed and implemented without departing from the spirit of the present invention. It is possible. ( 1 ) A coil spring is provided between each of the two spiders and each of the washers joined to the spiders. ( 2 ) Change the number and shape of the clamp arms appropriately according to the type of work. ( 3 ) The present invention is carried out in a finger chuck in which centering claws are provided on the inner peripheral side of the work. ( 4 ) To carry out the present invention in a finger chuck that holds a workpiece only with a clamp arm, that is, does not have a centering claw.

[0021]

As described above in detail, according to the invention of claim 1, the front and rear two spiders are driven by a single draw member, so that the number of parts of the drive system can be reduced and the overall length of the chuck can be reduced. This has an excellent effect that the driving force can be shortened, the driving means having a simple structure can be used, and the man-hours for attaching and detaching the chuck can be reduced.

The engaging portion of the rear washer is connected to the front washer.
Since the engaging portion is engaged through the through hole, only one abutting portion is needed, and the draw member can be shortened.

Further, since the washer of the rear side spider is accommodated in the accommodation hole of the front side spider, there is an effect that each washer can be compactly assembled in a limited space on the draw member in a superposed state.

According to the second aspect of the present invention, since the elastic body is interposed between the rear spider and the washer, the gripping force of each clamp arm is substantially equal when the thickness of the work is uneven. There is an effect that can be adjusted to.

[Brief description of drawings]

FIG. 1 is a front view of a finger chuck showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is an enlarged sectional view taken along line CC of FIG.

5 is a cross-sectional view taken along line DD of FIG.

FIG. 6 is a cross-sectional view showing another embodiment of the spider drive mechanism.

7 is a cross-sectional view taken along the line EE of FIG.

FIG. 8 is a sectional view showing a conventional finger chuck.

[Explanation of symbols]

1 ... Chuck body, 7 ... Draw member, 10 ... Front side spider, 10a ... Receiving hole, 11 ... Rear side spider, 12 ... Contact part, 13 ... First washer, 13a ... Engagement Part, 13b ... through hole, 14 ... second washer, 14a.
・ Convex portion, 14b ・ ・ Engaging portion, 15 ・ ・ Coil spring, 17 ・ ・ Clamp arm, W ・ ・ Workpiece

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23B 31/18 B23B 31/12 B23B 31/10

Claims (2)

(57) [Claims] 1. A front and rear spa provided inside a chuck body.
Juxtaposed to Ida, respectively connecting a plurality of clamp arms each spider, in the center of the chuck body movable a single draw member extending through the respective spider in the axial direction, the outer peripheral one position of the draw member The rear side with a spherical contact
The first washer on the front side of the front spider that is projecting and close to the contact part.
And the second washer to the front of the rear spider,
A housing hole for housing the second washer is formed in the front spider,
The first washer is provided with an engaging portion that makes spherical contact with the abutting portion.
A through hole is formed on the second washer, and a convex portion that fits into the through hole is formed on the second washer.
And the engaging part that makes spherical contact with the abutting part is formed on the convex part.
The driving force of one draw member is spy on the front and back through each washer.
A finger chuck configured to be separately transmitted to the da . Wherein at least one spider and the finger chuck according to claim 1, wherein the elastic member is interposed between the washer to be joined thereto.