JP3099461B2 - Workpiece holding mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding mechanism provided on a headstock or the like.

[0002]

2. Description of the Related Art Conventionally, as a work gripping mechanism for increasing the opening of a chuck to facilitate the insertion of a work, and for securely clamping the work even when the size of the work varies greatly, Japanese Utility Model Publication No. No. 22623 is known. The outline of this technology is as follows. That is, the drive wheel and the ratchet wheel are provided on the axis of the fixed shaft in the headstock so as to be relatively rotatable, and the eccentric cam is pivotally supported on the ratchet wheel at substantially equal positions on the circumference, and the ratchet wheel projects from the drive wheel. The engaging bolt is engaged with the eccentric cam. By providing a spring between the ratchet wheel and the drive wheel, the ratchet wheel is always urged in the direction in which the eccentric cam clamps the workpiece. Also, by operating a linear motion cylinder device that simultaneously moves the restraint shaft and the ratchet attached to the front end of the headstock into and out, the restraint shaft engages with the drive wheel to prevent the drive wheel from rotating,
The ratchet engages with the ratchet wheel to rotate the ratchet wheel in the direction opposite to the biasing direction of the spring, thereby turning the eccentric cam in the opening direction to bring it into the unclamped state. Workpieces are attached and detached in this unclamped state. According to this technique, the eccentric cam is turned in the biasing direction of the spring by releasing the rotation constraint of the drive wheel, so that the work piece can be reliably clamped. .

[0003]

In such a conventional work gripping mechanism, a large space for installing a linear motion cylinder device for moving the stop shaft and the ratchet forward and backward is required on the front surface of the headstock. However, there is a problem that the truing parts such as a sizing device, an end face measuring device, and a temporary receiving stand installed near the headstock are obstructed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and does not require the installation of a direct acting cylinder device or the like on the front surface of a headstock. An object of the present invention is to provide a workpiece gripping mechanism capable of gripping.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a driving member rotatably mounted on a headstock and a concentrically fixed driving member. A rotating face plate, a conical cam arranged at the center of the rotating face plate so as to be able to advance and retreat in the rotation axis direction of the driving member, and a cover plate fixed to the rotating face plate,
It is disposed between the rotating face plate and the cover plate, and is supported so as to be swingable about an axis parallel to the rotation axis at an equiangular distribution position in a circumferential direction of the rotating face plate. A plurality of swing levers which engage with a tapered surface of a cam and swing radially outward of the rotating face plate; and are arranged at equal angles around the rotation axis on the cover plate and engage with the swing lever. A holder supported so as to be openable and closable in accordance with the swing of the swing lever, a spring for constantly biasing the holder in a closing direction, a gripping claw attached to the tip of the holder, and a gripping claw of the workpiece. Prior to insertion into the workpiece, the cone cam is moved in the axial direction to swing the swing lever to open the holder against the spring, and after the workpiece is inserted between the gripping claws, the cone cam is moved to the other side. To the side and the holder by the spring And retractable actuating actuator to close, in which a motor for rotating the drive member.

[0006]

In the work holding mechanism configured as described above, when the conical cam is retracted, the holding claws attached to the holder are urged in the closing direction by a spring to clamp the work. When the conical cam is moved forward, the conical cam and the swing lever come into contact with each other, and the swing lever pivots outward from the rotary face plate. Due to this turning, the holder operates in the opening direction against the urging force of the spring to enter an unclamped state.

[0007]

Embodiments of the present invention will be described with reference to the drawings. 1 is a headstock, 2 is a fixed shaft fixed to the headstock 1 and fitted with a spindle center 3. A drive pulley 4 (drive member) is rotatably supported on the fixed shaft 2, and is rotatably driven by a motor 28.

Reference numeral 5 denotes a rotary face plate fixed to the drive pulley 4, and a cover plate 20 is attached to the rotary face plate 5 in parallel. The cover plate 20 has a space in an oblique direction as shown by a broken line in FIG. 2, and is bolted to the rotating face plate 5 via support portions 20a and 20b separated by the space. Also this space,
That is, a pair of swing levers 22 are pivotally supported between the cover plate 20 and the rotating face plate 5 so as to be opposed and swing by the support pins 23. The swing lever 22 has a roller 24 to which the connecting pin 30 is fixed and which engages with the conical cam 16 described later.

On the front surface of the cover plate 20, there is provided a holder 32 which is slidably supported in the center direction of the cover plate 20 and which rotates integrally with the cover plate 20. The holder 32 is connected to the swinging lever 22 through the above-described connecting pin 30 penetrating the cover plate 20 and the loose fitting hole 32a, and has a long hole 32b formed long in the center direction of the cover plate 20, The drive force transmitting pins 36 protruding from the cover plate 20 are supported so as to be able to engage with the cover plate 20 in the rotational direction. The holder 32 is restrained in the left-right and front-rear directions in FIG. 2 by a support member 33, and is guided and supported by a connecting bolt 26 via a dry bearing 34. The connecting bolt 26 has springs 27 at both ends and penetrates the pair of holders 32, and the holders 32 are urged by the springs 27 in a closing direction in which the holders 32 always approach each other. Here, the approaching ends of the holders 32 are restrained by stoppers 35 and 36 attached to the holder 32 and the cover plate 20. The V-shaped recess 2 is provided at the tip of the holder 32.
5a is attached, and this gripping claw 2
The mounting position of the five springs 271 as shown in FIG.
It is set to be on a plane B including the central axis.

Reference numeral 16 denotes a conical cam, which is disposed at the center of the rotating face plate 5 so as to be able to advance and retreat in the axial direction of the fixed shaft 2, and abuts against the roller 24 of the swing lever 22 by forward movement. The reciprocating operation mechanism of the conical cam 16 includes a piston 19 in a cylinder 18 disposed behind the fixed shaft 2 and an operating rod 1.
7 are connected. Next, the operation of the workpiece holding mechanism of the present embodiment will be described. In the above configuration, the conical cam 16 is normally located at the retracted end, and the pair of holders 32 are closed by the gripping claws 25 approaching each other due to the pressing force of the spring 27.

When the workpiece W is to be clamped from this state, the cylinder 18 is operated to move the conical cam 16 to 16a.
Forward to the position. The forward movement of the swing lever 22
The taper surface of the conical cam 13 abuts against the roller 24 attached to the roller 24, and the swing lever 22 rotates radially outward with the support pin 23 as a fulcrum (FIG. 4). Swing lever 22
The pair of holders 32 are connected to the swing lever 22 via the connecting pins 30 by the rotation of the gripping pins 25, so that the gripping claws 25 move in the direction of opening each other against the urging force of the spring 27,
The workpiece W can be clamped.

After the workpiece W is mounted on the main spindle center 3 of the fixed shaft 2 with the gripping claws 25 opened, the conical cam 16 is moved backward to move the conical cam 16 with the roller 24 of the swing lever 22. The contact is released, and the holders 32 approach each other due to the pressing force of the spring 27, contrary to the operation described above, and the workpiece W is automatically centered and clamped by the V-shaped recess 25a.

In this state, the drive pulley 4 is rotated by the motor 28 to rotate the rotary face plate 5 for processing the workpiece W. This rotational driving force causes the cover plate 20 to rotate integrally with the rotating face plate 5 and the driving force transmitting pins 36.
Similarly, the holder 32 on the cover plate 20 is also integrally rotated. By the above operation, the workpiece W gripped by the gripping claws 25 of the holder 32 is driven to rotate.

In order to unclamp the workpiece W from the state in which the workpiece W is rotationally driven, the motor 28 is stopped, and the conical cam 16 is advanced to the position 16a in the same manner as in the above-described state. By operating the lever 22 and the holder 32, the gripping claws 25 may be moved in a direction in which they are separated from each other. As described above, the workpiece gripping mechanism of the present embodiment can reliably perform clamping and unclamping of the workpiece W by using the forward and backward movements of the conical cam 16 inside the headstock 1, so that the spindle can be reliably used. A simplified configuration can be achieved without attaching a large device to the front of the base 1.

The work gripping mechanism of the present embodiment does not directly attach the gripping claw 25 to the swing lever 22,
The separate structure via the holder 32 enables the cover plate 20 to suppress the action of the swing lever 22 moving in the same direction as the forward and backward movement of the conical cam 16, and the attachment of the gripping claws 25. Since the position is set to be on a plane including the central axes of the two springs 27, the pressing force of the springs 27 and the force direction necessary for gripping the workpiece W are completely coincident with each other. Nail 2
No extra force acts on the workpiece 5, and the workpiece W can be reliably gripped.

[0016]

As described above, the work holding mechanism of the present invention can reliably clamp and unclam the work by utilizing the forward and backward movement of the conical cam. There is no need to mount a linear motion cylinder device or the like operating in the clamped state on the front surface of the headstock, so that the configuration of the entire workpiece gripping mechanism is simplified and a space in front of the headstock is secured.

Further, in the workpiece gripping mechanism of the present invention, a gripping claw is directly attached to a swing lever for converting the movement of the conical cam in the forward and backward directions into the outward movement of the rotary face plate which is a direction perpendicular to the direction. Instead of using a separate structure via a holder, the cover plate can suppress the action of the swing lever trying to move in the same direction as the forward and backward movement of the conical cam. Since it is mounted on the same plane, the pressing force of the spring and the direction of force required to grip the workpiece are completely matched, so that extra force may act on the gripping claws. Therefore, the workpiece can be securely gripped.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a workpiece gripping mechanism according to the present embodiment.

FIG. 2 is a front view of the workpiece gripping mechanism of the embodiment.

FIG. 3 is a view as viewed in the direction of arrows AA in FIG. 2;

FIG. 4 is a diagram illustrating a swing lever of the workpiece holding mechanism according to the present embodiment.

[Explanation of symbols]

 Reference Signs List 1 headstock 2 fixed shaft 4 drive pulley 5 rotating face plate 13 conical cam 18 cylinder 20 cover plate 22 swing lever 25 gripping claw 27 spring 28 motor 32 holder

──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 49-116680 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B23B 31/36

Claims (1)

(57) [Claims] 1. A driving member rotatably supported on a headstock, a rotating face plate fixed concentrically to the driving member, and a center portion of the rotating face plate capable of moving forward and backward in the direction of the rotation axis of the driving member. A conical cam arranged, a cover plate fixed to the rotating face plate, and the rotating face plate and the cover plate fixed to the rotating face plate.
Placed between the plates, etc. in the circumferential direction of the rotating face plate
Around the axis parallel to the rotation axis at the angle distribution position
It is swingably supported, and when the cone cam moves in the axial direction,
And swings radially outward of the rotating face plate
A plurality of swinging levers to move and
It is arranged at an equal angle around the rotation axis and engages with the swing lever.
A hook supported so that it can open and close according to the swing of the swing lever
A holder, a spring for biasing the holder always closing direction, the gripping claws attached to the distal end of the holder, tool
Prior to inserting the object between the gripping claws, the conical cam is moved in the axial direction.
To swing the rocking lever against the spring
After opening the holder and inserting the workpiece between the gripping claws,
Move the conical cam to the other side and close the holder with the spring.
A workpiece gripping mechanism , comprising: an advancing / retracting actuator for rotating the driving member; and a motor for rotating the driving member.