JP2003039293A - Work clamp device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the conventional problem that clamping a workpiece takes a long time and as to a soft glassy material or the like, some manual intervention is required. SOLUTION: The work clamp device is provided with a fixed side clamp shaft 13, work suction means 18 and 19 which suck and hold a workpiece W at the top of the fixed side clamp shaft 13, a movable side clamp shaft 14 which is located on a line with the fixed side clamp shaft 13 and is movable forward/backward in the opposite direction against the fixed side clamp shaft 13 and can grip the workpiece W cooperating with the fixed side clamp shaft 13, and a clamp shaft forward/backward drive means which drives the movable side clamp shaft 14 forward/backward. The clamp shaft reciprocating means is provided with low speed drive means 40, 41, 43 and 45 which drive the movable side clamp shaft 14 in a zone near the fixed side clamp shaft 13 at a low speed and high speed drive means 33 to 37 and 39 which drive the movable side clamp shaft 14 in a zone apart from the fixed side clamp shaft 13 at a high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work clamp device for holding a work by a pair of clamp shafts.
It is particularly suitable for application to a bell clamp type lens centering machine.

[0002]

2. Description of the Related Art When an outer peripheral surface of a lens or other optical element whose optical surface has been polished is aligned concentrically with the optical axis of the lens by a lens centering machine, the optical element must be accurately mounted on the lens centering machine. It is necessary to attach it, and for example, a bell clamp type work clamp device is used.

FIG. 5 shows a schematic structure of a conventional bell clamp type lens centering machine incorporating such a work clamping device. That is, the optical element W such as a lens is set and suction-fixed by a handling device (not shown) to the bell holder 102 attached to the lower end of the fixed-side clamp shaft 101 that is driven to rotate. At the upper end of the movable clamp shaft 103, which is linearly opposed to the fixed clamp shaft 101 and is driven to rotate and reciprocally driven in a direction parallel to the axis, a bell holder 104 for sandwiching the optical element W with the bell holder 102 is provided. It is installed. The fixed side clamp shaft 101 is rotatably supported on the housing 105 via a pair of air bearings 106, and the movable side clamp shaft 104 is rotatable on the housing 105 via an air bearing 107 and its axis line. It is supported so that it can reciprocate in parallel directions. These air bearings 106,
Compressed air is supplied to each 107 via the air supply connector 108.

A thrust plate 110 having a transmission gear 109 formed on the outer periphery is integrally fixed to the upper end of the fixed side clamp shaft 101. The thrust plate 110 is composed of an upper thrust case 111 and a lower thrust case 112. On the other hand, it is sandwiched by a pair of upper and lower thrust air bearings 113, and the displacement in the direction parallel to the axis is restricted. Compressed air is supplied to each of the thrust air bearings 113 via the air supply connector 114.

A lower intermediate gear 119 at the lower end of an intermediate shaft 118 rotatably attached to the housing 105 via two pairs of upper and lower bearings 117 meshes with the drive gear 116 of the clamp shaft rotary drive motor 115. The lower intermediate gear 119 is meshed with a transmission gear 120 integrally provided under the movable clamp shaft 104. Further, the upper intermediate gear 121 provided on the upper end of the intermediate shaft 118 is the transmission gear 1 of the thrust plate 110 described above.
The fixed side clamp shaft 101 and the movable side clamp shaft 103 are synchronously driven and rotated.

The lower end of the movable clamp shaft 103 is mounted on the upper end of a pivot pin 123 via a pivot bearing 122, and a slider 124 for rotatably supporting the pivot pin 123 is provided with the housing 105. It is attached to an integral bracket base 125 via a linear guide mechanism 126 so as to be able to move up and down. Air cylinder 127 mounted upward on the bracket base 125
The piston rod 128 of the
The movable-side clamp shaft 103 is vertically moved integrally with the piston rod 128 by the vertical movement of the piston rod 128.

[0007]

In the conventional work clamp device shown in FIG. 5, an optical element W such as a lens is used.
Is clamped by the fixed side clamp shaft 101 and the movable side clamp shaft 103 via the bell holders 102 and 104,
In order to prevent damage to the optical surface formed on the optical element W,
Low-pressure air is slowly supplied to the air cylinder 127 to extend the piston rod 128 at an extremely low speed, and the impact force when the bell holder 104 contacts the optical element W is mitigated. Therefore, it takes a very long time from the start of supplying air to the air cylinder 127 until the bell holder 104 contacts the optical element W and clamps it.

Further, since the moving speed of the piston rod 128 in the air cylinder 127 is adjusted by adjusting the air pressure supplied to the air cylinder 127 and the flow rate thereof, delicate speed control is basically difficult. In particular, with regard to soft glass materials such as single crystal materials, the current situation is that they must be done manually.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a work clamp device capable of quickly and easily clamping a work without damaging the work.

[0010]

A work clamp device according to the present invention comprises a fixed side clamp shaft, and a work suction means for sucking and holding a work at the tip of the fixed side clamp shaft.
A movable side clamp that is arranged so as to be in line with the fixed side clamp shaft, is capable of reciprocating in a direction opposite to the fixed side clamp shaft, and is capable of sandwiching a work with the fixed side clamp shaft. A work clamp device comprising: a shaft; and a clamp shaft reciprocating drive means for reciprocally driving the movable clamp shaft in a direction opposite to the fixed clamp shaft, wherein the clamp shaft reciprocating drive means is the movable clamp. Low-speed driving means for driving the shaft at a low speed in a region close to the fixed-side clamp shaft, and high-speed driving means for driving the movable-side clamp shaft at a high speed in a region distant from the fixed-side clamp shaft. It is characterized by.

In the present invention, the work suction means is operated to suction and hold the work at the tip of the fixed side clamp shaft,
From this state, the clamp shaft reciprocating drive means is operated, and first the high speed drive means moves the movable side clamp shaft forward toward the fixed side clamp shaft side at high speed, and when the tip of the movable side clamp shaft approaches the work piece, it becomes the low speed drive means. The movable-side clamp shaft is advanced at a low speed so that the tip of the movable-side clamp shaft abuts without impacting the work, and the work is clamped by the tip of the fixed-side clamp shaft and the tip of the movable-side clamp shaft.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The work clamp device according to the present invention can further include a clamp shaft rotation drive means for synchronously driving and rotating the fixed side clamp shaft and the movable side clamp shaft.

The low-speed driving means includes a cam member, an actuator for driving the cam member, and the movable-side clamp shaft moving toward the fixed-side clamp shaft side by the high-speed driving means.
It may have a stopper that comes into contact with the cam surface of the cam member and functions as a cam follower thereof. in this case,
The movable shaft side clamp shaft may be reciprocally supported and further includes a bracket to which the cam member and the actuator are attached, and the stopper may be connected to the movable side clamp shaft and reciprocate integrally therewith. It is possible to further include a detent mechanism for preventing the stopper from rotating along with the rotation of the movable clamp shaft by the rotation driving means.

Alternatively, the low speed driving means includes a linear actuator having a plunger capable of retracting at a low speed in the reciprocating direction of the movable side clamp shaft, and movement of the movable side clamp shaft to the fixed side clamp shaft side by the high speed drive means. And a receiving block with which the tip of the plunger abuts. In this case, the movable-side clamp shaft may be reciprocally supported and a bracket to which the receiving block is attached may further be provided, and the linear actuator may be connected to the movable-side clamp shaft and reciprocate integrally therewith. Further, it is possible to further include a rotation stopping mechanism that prevents the linear motion actuator from rotating along with the rotation of the movable side clamp shaft by the clamp shaft rotation driving means.

[0015]

FIG. 1 shows an embodiment in which a work clamp device according to the present invention is incorporated in a bell clamp type lens centering machine.
~ It will be described in detail with reference to Fig. 4, but the present invention is not limited to these examples, and all changes and modifications included in the concept of the present invention described in the claims are possible, Therefore, it can be naturally applied to other techniques belonging to the spirit of the present invention.

FIG. 1 shows the cross-sectional structure of the main part in this embodiment.
Shown in. That is, the working space 1 for centering work in the center
In the frame-shaped housing 12 in which 1 is formed, the fixed-side clamp shaft 13 whose lower end faces the working space 11 and the movable-side clamp shaft 14 whose upper end faces the working space 11 are arranged in a straight line, respectively. It is rotatably supported via air bearings 15 and 16. An upper bell holder 17 for suction-holding an optical element such as a lens, which is the workpiece W, is provided at the lower end of the fixed clamp shaft 13 so as to project downward. The upper bell holder 17 is formed at the center of the fixed clamp shaft 13. The suction connector 19 attached to the upper end of the fixed side clamp shaft 13 is connected via the suction passage 18, and the other end of the pipe (not shown) whose one end is connected to a suction pump (not shown) is connected to this suction connector 19. It is detachably connected. That is, the work suction means in the present invention is constituted by the suction passage 18, the suction connector 19, the suction pump, the piping, etc. described above. At the upper end of the movable side clamp shaft 14 aligned with the fixed side clamp shaft 13, a lower bell holder 20 for sandwiching the work W with the upper bell holder 17 is provided so as to project upward, and the suction pump described above operates. Stops after the work W is clamped by the upper and lower bell holders 17, 20.

A pair of air bearings 15 for rotatably supporting the fixed side clamp shaft 13 is formed in the housing 12 from a compressor (not shown) connected to the air supply connector 21 attached to the housing 12 through a pipe. Compressed air is supplied through the air supply path 22. A disk-shaped thrust plate 23 is integrally fitted to the upper end of the fixed-side clamp shaft 13 protruding upward from the upper end of the housing 12, and the thrust plate 23 is fixed to the upper end of the housing 12. It is sandwiched between the lower thrust case 24 and the upper thrust case 25 which is superposed on the lower thrust case 24, and only the rotation of the housing 12 is permitted.
Thrust air bearings 26 are provided between the thrust plate 23 and the upper and lower thrust cases 24, 25, respectively. In these thrust air bearings 26, air formed in the thrust cases 24, 25 from a compressor (not shown) connected to air supply connectors 27 attached to the upper and lower thrust cases 24, 25 via pipes (not shown), respectively. Compressed air is supplied through the supply paths 28, respectively.

An air bearing 16 for rotatably supporting the movable clamp shaft 14 is formed in the housing 12 from a compressor (not shown) connected to an air supply connector 29 attached to the housing 12 via a pipe (not shown). Compressed air is supplied through the air supply passage 30, and the movable clamp shaft 14 is also capable of reciprocating in the direction opposite to the fixed clamp shaft 13. Movable side clamp shaft 1
4, a bracket base 33 attached to the lower end of a support column 32 extending downward from a gear case 31 fixed to the lower end of the housing 12 is located, and a linear guide mechanism 34 is attached to the bracket base 33. A slider 35 is attached via the slider 35 so as to be movable up and down. Slider 3
Pivot pin 36 rotatably attached to 5
The lower end of the movable clamp shaft 14 is rotatably mounted on the upper end of the movable clamp shaft 14 via a pivot bearing 37. An air cylinder 39 having a piston rod 38 vertically penetrating the bracket base 33 is attached upward to the lower side of the bracket base 33, and the lower end of the pivot pin 36 is connected to the piston rod 38 of the air cylinder 39. . A compressor (not shown) is connected to the air cylinder 39, and the piston rod 38 is expanded and contracted by supplying and discharging compressed air from the compressor to the air cylinder 39, so that the movable clamp shaft 14 can be moved up and down. That is, the bracket base 33, the linear guide mechanism 34, the slider 35, the pivot bearing 37, the pivot pin 36, the air cylinder 39, and the like described above constitute a high-speed drive means of the clamp shaft reciprocating drive means.

FIG. 1 and FIG. 2 showing its II-II arrow shape.
As shown in FIG. 4, the lower end of the slider 35 has a cam follower 43 that can come into contact with the outer peripheral surface of the rotary cam 41 rotatably attached to the upper end of the cam holder 40 provided upright on the bracket base 33, that is, the cam surface 42. Is rotatably attached, and the slider 35, the pivot pin 36, the pivot bearing 37, and the like described above constitute a rotation stopping mechanism for the cam follower 43 according to the present invention. Rotating cam 41
A stepping motor 45 attached to the cam holder 40 is connected to the rotation shaft 44 of the above as an actuator of the present invention, and the stepping motor 45 is rotated counterclockwise from the initial rotation position shown in FIG.
The rotation is weak and it turns at a low speed. Specifically, with the extension of the piston rod 38 of the air cylinder 39, after the cam follower 43 comes into contact with the cam surface 42 indicated by the chain double-dashed line from a state where the cam follower 43 is separated from the cam surface 42 indicated by the solid line in FIG. The stepping motor 45 is driven, and the position of the cam follower 43 that is pressed against the outer peripheral surface of the rotary cam 41 by the air cylinder 39 gradually rises as the rotary cam 41 turns, as shown in FIG. In other words, until the cam follower 43 contacts the rotating cam 41, the piston rod 3
8 raises the movable side clamp shaft 14 at high speed, and after the cam follower 43 abuts on the rotary cam 41,
As a result of the turning, the ascending speed of the movable side clamp shaft 14 is reduced, and as a result, the upper end of the lower bell holder 20 is pressed against the work W without impact. That is,
The cam holder 40, the rotating cam 41, the stepping motor 45, the cam follower 43, and the like described above constitute the low-speed driving means of the clamp shaft reciprocating driving means of the present invention.

The lower bell holder 2 for the work W
The pressing force of 0 is determined by the air pressure supplied to the air cylinder 39. In this case, the upper end of the lower bell holder 20 abuts against the work W while the cam follower 43 is rising from the state shown in FIG. 2 to the state shown in FIG.
3 and the movable side clamp shaft 14 stops rising,
It is preferable to set the cam profile of the cam surface 42 according to the thickness of the work W so that a gap is formed between the cam surface 42 of the rotating cam 41 and the cam follower 43.

The drive gear 47 of the clamp shaft rotary drive motor 46 installed in the gear case 31 has upper and lower end portions, respectively, via bearings 48, and the upper and lower clamp shafts 13, 1, respectively.
A lower intermediate gear 50 provided at a lower end of an intermediate shaft 49 rotatably supported by the housing 12 in parallel with the gear 4 is meshed with the intermediate shaft 49. The lower intermediate gear 50 is meshed with a transmission gear 51 that is integrally fitted to the lower portion of the movable clamp shaft 14, and maintains the meshed state regardless of whether the movable clamp shaft 14 moves up and down. In this embodiment, the tooth width of the lower intermediate gear 50 is set according to the lifting stroke of the movable clamp shaft 14. The upper intermediate gear 52 provided at the upper end of the intermediate shaft 49 includes the thrust plate 23.
The transmission gear 53 engraved on the outer periphery of the
The upper intermediate gear 52 and the lower intermediate gear 50 have the same pitch circle diameter and the same number of teeth, and the transmission gear 5 meshes with them.
1, 53 also have the same pitch circle diameter and the same number of teeth.
Accordingly, by operating the clamp shaft rotary drive motor 46, the fixed side clamp shaft 13 and the movable side clamp shaft 14 are synchronously rotated at the same speed, and these clamp shaft rotary drive motor 46, drive gear 47, The intermediate shaft 49, the upper and lower intermediate gears 52 and 52, the upper and lower transmission gears 51 and 53, and the like constitute the clamp shaft rotation driving means in the present invention.

In actual work, the movable clamp shaft 14 is retracted to the retracted position at the descending end shown in FIG.
The work W is set on the upper bell holder 17 at the lower end of the fixed clamp shaft 13 by a handling device (not shown), and the suction pump is operated to suck and fix the work W to the upper bell holder 17. Next, the air cylinder 39 is operated to raise the movable clamp shaft 14 at high speed until the cam follower 43 comes into contact with the lower end of the rotating cam 41 at the initial position shown in FIG. 2, and then the stepping motor 45 is operated. The rotating cam 41 is rotated to raise the movable clamp shaft 14 at a low speed. As a result, the lower bell holder 20 at the upper end of the movable clamp shaft 14 gently presses against the lower surface of the work W,
The work W is clamped by the upper and lower bell holders.

Thereafter, the pipe is removed from the suction connector 19 and the clamp shaft rotation drive motor 46 is operated to operate the work W.
Is clamped between the fixed-side clamp shaft 13 and the movable-side clamp shaft 14, and is synchronously rotated, and the outer peripheral surface of the work W is ground using a dressing device or the like (not shown).

In the above-mentioned embodiment, the low speed driving means of the present invention is constructed by using the rotary cam 41, but the low speed driving means of the present invention can be constructed by using a direct acting actuator.

FIG. 4 shows a schematic structure of a main part of the work W clamp device according to the present invention. The basic structure other than this is the same as that of the previous embodiment. Components that are basically the same as those in the embodiment will be denoted by the same reference numerals, and redundant description will be omitted. That is, the linear motion actuator 54 penetrating the bracket base 33 is attached to the lower end of the slider 35. The shaft 55 of the linear motion actuator 54 can be retracted at a low speed in a direction parallel to the upper and lower clamp shafts 13 and 14, and is in an extended position where it projects upward in the initial state. The receiving block 56, which faces the tip of the shaft 55 and can abut against it, is erected on the bracket base 33, and at the lower end of the movable side clamp shaft 14, the tip of the shaft 55 in the extended position and the receiving block. A predetermined gap with 56 is formed.

Therefore, from this state, the air cylinder 39 is driven to move the movable side clamp shaft 14 at a high speed until the upper end of the shaft 55 of the linear actuator 54 contacts the receiving block 56 as shown by the chain double-dashed line in the figure. To raise. Then, after the upper end of the shaft 55 of the linear motion actuator 54 contacts the receiving block 56, the linear motion actuator 5
4 is operated to slowly retract the shaft 55, the air pressure supplied to the air cylinder 39 causes the movable clamp shaft 14 to rise at a low speed, and the lower bell holder 20 at the upper end gives a shock to the work W. Without contact, the work W is held by the upper and lower bell holders.

In the above-mentioned two embodiments, the directions of the rotation axes of the pair of clamp shafts 13 and 14 are both set to the vertical direction, but it is naturally possible to set the directions of these rotation axes to the horizontal direction. is there.

[0028]

According to the work clamp device of the present invention,
The clamp shaft reciprocating drive means for reciprocating the movable side clamp shaft in the opposite direction to the fixed side clamp shaft, and the low speed drive means for driving the movable side clamp shaft at a low speed in a region close to the fixed side clamp shaft, Since it has a high-speed drive unit that drives the side clamp shaft at a high speed in a region away from the fixed side clamp shaft, the movable side clamp shaft is moved at high speed by the high-speed drive unit until just before the movable side clamp shaft contacts the workpiece. Further, the low-speed driving means makes it possible to bring the movable-side clamp shaft into contact with the work without giving an impact, and the clamping work and the unclamping work can be performed quickly and safely.

The low speed drive means moves the movable member side clamp shaft to the fixed side clamp shaft side by the cam member, the actuator for driving the cam member, and the high speed drive means,
In the case of having a stopper that comes into contact with the cam surface of the cam member and functions as the cam follower, in particular, a bracket that supports the movable side clamp shaft so that it can reciprocate and a cam member and an actuator are mounted is provided, and the stopper is attached to the movable side clamp shaft. In the case of connecting and reciprocating integrally with this, a transition from the high speed movement of the movable side clamp shaft by the high speed drive means to the low speed movement of the movable side clamp shaft by the low speed drive means, or the reverse operation thereof, Therefore, the conventional electric speed control device is unnecessary,
The moving speed of the movable side clamp shaft can be reliably switched with a simple structure. Further, by using the cam member having a different cam profile depending on the work, the movable clamp shaft can be brought into contact with the work at an optimum speed.

When the clamp shaft rotation driving means for synchronously driving and rotating the fixed side clamp shaft and the movable side clamp shaft is provided, when the work is an optical component such as a lens, centering work is performed subsequent to the clamping work. be able to.

When a rotation stopping mechanism is provided to prevent the stopper from rotating along with the rotation of the movable clamp shaft by the clamp shaft rotation driving means, when the movable clamp shaft rotates synchronously with the fixed clamp shaft. In addition, it is possible to prevent the problem that the stopper rotates together.

The low speed driving means has a linear actuator having a shaft which can be retracted at a low speed in the reciprocating direction of the movable side clamp shaft, and the high speed driving means moves the movable side clamp shaft to the fixed side clamp shaft side. If the shaft has a receiving block with which the tip of the shaft abuts, a bracket for supporting the movable clamp shaft so as to reciprocate and mounting the receiving block is provided, and the linear actuator is connected to the movable clamp shaft. When they are integrally reciprocated, the high-speed driving means moves the movable-side clamp shaft from high speed to the low-speed driving means to move the movable-side clamp shaft to low speed, or vice versa. , The conventional electric speed control device is unnecessary,
The moving speed of the movable side clamp shaft can be reliably switched with a simple structure. Further, by using the linear actuator in which the stroke and the reciprocating speed of the shaft differ depending on the work, the movable clamp shaft can be brought into contact with the work at an optimum speed.

In the case where a rotation stopping mechanism for preventing the rotation of the linear actuator against the rotation of the movable clamp shaft by the clamp shaft rotation driving means is provided, the movable clamp shaft rotates synchronously with the fixed clamp shaft. When doing so, it is possible to prevent the problem that the linear motion actuator rotates together.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic structure of an embodiment in which a work clamp device according to the present invention is incorporated in a bell clamp type lens centering machine.

FIG. 2 is a view on arrow II-II in FIG.

FIG. 3 is a view taken along the line II-II in FIG. 1 showing a state during clamping of the work.

FIG. 4 is a sectional view showing a schematic structure of a main part in another embodiment in which the work clamp device according to the present invention is incorporated into a bell clamp type lens centering machine.

FIG. 5 is a sectional view showing a schematic structure of a conventional bell clamp type lens centering machine.

[Explanation of symbols]

W work 11 workspace 12 housing 13 Fixed side clamp shaft 14 Movable side clamp shaft 15,16 Air bearing 17 Upper bell holder 18 suction passage 19 Suction connector 20 Lower bell holder 21 Air supply connector 22 Air supply path 23 Thrust plate 24 Lower thrust case 25 Upper thrust case 26 Thrust air bearing 27 Air supply connector 28 Air supply path 29 Air supply connector 30 air supply path 31 gear case 32 props 33 bracket base 34 Linear guide mechanism 35 slider 36 pivot pin 37 Pivot bearing 38 Piston rod 39 Air cylinder 40 cam holder 41 rotating cam 42 Cam surface 43 Cam Follower 44 rotation axis 45 stepping motor 46 Clamp shaft rotation drive motor 47 drive gear 48 bearings 49 Intermediate shaft 50 Lower middle gear 51 transmission gear 52 upper middle gear 53 transmission gear 54 Linear actuator 55 shaft 56 receiving block

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Claims (8)

[Claims] 1. A fixed-side clamp shaft, a work suction means for sucking and holding a work at a tip of the fixed-side clamp shaft, and a fixed-side clamp shaft, which are arranged so as to be in line with each other. A movable side clamp shaft that is capable of reciprocating in the direction opposite to the clamp shaft and that can clamp a workpiece between the fixed side clamp shaft, and the movable side clamp shaft in the direction opposite to the fixed side clamp shaft. A work clamp device comprising a reciprocating clamp shaft reciprocating driving means, wherein the clamp shaft reciprocating driving means drives the movable side clamp shaft at a low speed in a region close to the fixed side clamp shaft. A workpiece clamping device comprising: means and a high-speed drive means for driving the movable-side clamp shaft at a high speed in a region apart from the fixed-side clamp shaft. 2. The work clamp device according to claim 1, further comprising clamp shaft rotation driving means for synchronously driving and rotating the fixed clamp shaft and the movable clamp shaft. 3. The low speed drive means includes a cam member, an actuator for driving the cam member, and the cam member according to movement of the movable side clamp shaft toward the fixed side clamp shaft side by the high speed drive means. The work clamp device according to claim 1 or 2, further comprising a stopper that comes into contact with the cam surface of the above and functions as a cam follower thereof. 4. A bracket, which supports the movable clamp shaft so as to reciprocate, and further has a bracket to which the cam member and the actuator are attached, wherein the stopper is connected to the movable clamp shaft and reciprocates integrally therewith. The work clamp device according to claim 3, wherein the work clamp device moves. 5. The work according to claim 4, further comprising a rotation stopping mechanism for preventing rotation of the movable side clamp shaft by the clamp shaft rotation driving means against rotation of the stopper. Clamp device. 6. The low speed drive means includes a linear actuator having a shaft that can be retracted at a low speed in the reciprocating direction of the movable clamp shaft, and the high speed drive means moves the movable clamp shaft toward the fixed side clamp shaft. The work clamp device according to claim 1 or 2, further comprising a receiving block with which a tip of the shaft abuts as the side clamp shaft moves. 7. A bracket for supporting the movable clamp shaft so as to be reciprocally movable and further having a bracket to which the receiving block is attached, wherein the linear actuator is connected to the movable clamp shaft and reciprocates integrally therewith. The work clamp device according to claim 6, wherein: 8. The rotation stop mechanism for preventing rotation of the movable side clamp shaft against rotation of the movable side clamp shaft by the clamp shaft rotation driving means, further comprising a rotation stopping mechanism. Work clamp device.