CN214816838U

CN214816838U - Workpiece support

Info

Publication number: CN214816838U
Application number: CN201990000964.2U
Authority: CN
Inventors: 吉村画
Original assignee: Kosmek KK
Current assignee: Kosmek KK
Priority date: 2018-08-24
Filing date: 2019-06-27
Publication date: 2021-11-23
Anticipated expiration: 2029-06-27
Also published as: KR20210000480U; WO2020039738A1; KR200496444Y1; JP2020028968A; TWI716933B; DE212019000361U1; TW202015852A

Abstract

The application relates to a workpiece support, on which a support rod (2), an entry spring (43) and an output member (24) are mounted in sequence from the upper side on a housing (1). When the support rod (2) moves to the lower limit position, the support rod (2) may adhere to the casing (1) due to some abnormality. The sticking state is released by causing the engagement portion (70) of the output member (24) moving upward toward the support rod to collide with the engagement portion (71) of the support rod (2).

Description

Workpiece support

Technical Field

The present invention relates to a device for supporting a workpiece when the workpiece is machined by a machine tool such as a milling machine or a grinding machine.

Background

As such a work holder, there is a work holder described in patent document 1 (japanese patent application laid-open No. 2003-307205). This conventional technique is configured as follows.

The cylindrical support rod inserted into the upper wall of the housing is movable in the vertical direction in the housing. The output member is inserted into a lower portion of the housing so as to be movable in the up-down direction. The barrel hole of the support rod is screwed with a compression bolt. An entry spring is installed between the hold-down bolt and the output member, and the entry spring applies a force so as to separate the support rod from the output member. Then, the output member moves the support rod upward via the entry spring by being driven upward. Then, the upper end surface of the support block supports the lower surface of the workpiece placed on the mounting table from below. The urging force of the entry spring is set to have an urging force to such an extent as to overcome the self weight, frictional resistance, and the like of the support rod, but to such an extent as not to lift the workpiece from the mounting table. In addition, a sufficient gap is formed between the upper end portion of the output member and the lower end portion of the pressure bolt, and when the support rod moves to the lower limit position and the output member moves to the upper limit position, the pressure bolt and the output member do not abut against each other. Thereby, the output member is configured to indirectly press the work holder via the entry spring. As a result, the output member does not lift the workpiece from the mounting table via the workpiece holder, thereby preventing deterioration of the machining accuracy of the workpiece.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2003-307205

SUMMERY OF THE UTILITY MODEL

Problem to be solved by utility model

When the work holder is in the released state, the support rod may be stuck to the upper wall of the housing for some reason, for example, accumulated chips and cutting oil. In this case, even if the output member presses the support lever upward via the entry spring having a biasing force of such a degree that the work is not lifted as described above, the above-described stuck state cannot be released.

An object of the utility model is to provide a can relieve work support of work support's bracing piece and casing because the state that some reasons are adhered to together.

Means for solving the problems

In order to achieve the above object, a first embodiment is a work holder configured as follows, for example, as shown in fig. 1 to 3, 4, 5A, and 5B.

The support rod 2, which is movable toward the distal end side and the proximal end side in the axial direction in the housing 1, is inserted into the distal end wall 1a of the housing 1. An annular chuck 5 is embedded outside the periphery of the support rod 2. A piston 12 inserted into a cylinder hole 11 formed in the housing 1 in the axial direction locks the support rod 2 via the collet 5 by driving the piston 12 in the axial direction. The output member 24 is inserted into the base end wall 1b of the housing 1 so as to be movable in the axial direction. The support rod 2 and the output member 24 are urged apart by urging means. When the support rod 2 located at the limit position on the base end side is in a stuck state in which it is stuck to the housing 1 due to some abnormality, the output member 24 moves from the base end side to the tip end side, and the engaging portion 70 formed in the output member 24 pushes the engaging portion 71 formed in the support rod 2 from the base end side to release the stuck state. Further, the distance from the distal end surface of the support bar 2 in the released state to the workpiece W carried into the distal end direction position of the support bar 2 is set to be longer than the distance by which the output member 24 moves the support bar 2 toward the distal end side by the engaging portion 70.

In the work holder according to the first aspect described above, in the released state in which the work holder is moved to the limit position on the base end side, the support rod may adhere to the distal end wall of the housing for some reason, for example, chips and cutting oil accumulated on the distal end portion of the housing. In this case, the engagement portion of the output member is brought into contact with (collides with) the engagement portion of the support rod by moving the output member toward the distal end side. As a result, the adhesion state of the support lever to the housing can be reliably released.

The first embodiment preferably incorporates the following structures (1) to (3).

(1) For example, as shown in fig. 1 to 3, 4, 5A, and 5B, a distance S from a limit position on the base end side of the output member 24 to a limit position on the tip end side is set to be longer than a distance H from the engaging portion 70 of the output member 24 to the engaging portion 71 of the support lever 2.

In this case, the engaging portion of the output member reliably abuts (collides) with the locking portion of the support rod located at the limit position on the proximal end side. Therefore, the adhesion state between the support rod and the housing can be reliably released by the impact of the collision.

(2) The urging member is constituted by a working chamber 15 formed on the base end side of the support rod 2 and a working pressure fluid supplied to the working chamber 15.

In this case, the urging member configured as described above reliably raises the support rod.

(3) The urging means is constituted by an intake spring 43 mounted between the support rod 2 and the output member 24.

In order to achieve the above object, a second embodiment is to configure a work holder as follows, for example, as shown in fig. 6A and 6B.

The support rod 2, which is movable toward the distal end side and the proximal end side in the axial direction in the housing 1, is inserted into the distal end wall 1a of the housing 1. An annular chuck 5 is embedded outside the periphery of the support rod 2. A piston 12 is inserted into a cylinder hole 11 formed in the housing 1 in the axial direction. The piston 12 is driven to lock the support rod 2 via the collet 5. The output member 24 is inserted into the base end wall 1b of the housing 1 so as to be movable in the axial direction. An intake spring 43 installed between the support rod 2 and the output member 24 urges to separate the support rod 2 from the output member 24. When the entry spring 43 is compressed to the maximum, the adjacent windings of the entry spring 43 come into close contact with each other. When the support rod 2 located at the limit position on the base end side is in the adhesion state of adhering to the housing 1 due to some abnormality, the output member 24 pushes the support rod 2 from the base end side via the entry spring 43 in the adhesion state to release the adhesion state by the output member 24 moving from the base end side to the tip end side.

Drawings

Fig. 1 is a front sectional view showing a first embodiment of the present invention, and showing a released state of a work holder.

Fig. 2 is a front sectional view showing a locked state of the work holder, and is similar to fig. 1.

Fig. 3 is a front sectional view showing a state where the second piston of the work holder pushes up the support rod, and is similar to fig. 1.

Fig. 4 is a view similar to fig. 3, showing a second embodiment of the present invention.

Fig. 5A is a front cross-sectional view similar to fig. 1 showing a third embodiment of the present invention, and showing a released state of the work holder.

Fig. 5B is a front sectional view showing a third embodiment of the present invention, and is a view similar to fig. 3 showing a state where the second piston of the work holder pushes up the support rod.

Fig. 6A is a front cross-sectional view similar to fig. 1 showing a fourth embodiment of the present invention, and showing a released state of the work holder.

Fig. 6B is a front sectional view showing a fourth embodiment of the present invention, and is a view similar to fig. 3 showing a state in which the second piston of the work holder pushes up the support rod.

Detailed Description

Fig. 1 shows a first embodiment of the present invention. In this embodiment, the case where the present invention is applied to a pneumatic work holder is exemplified. First, the structure of the work holder will be described.

A housing 1 of a work holder is screwed into a receiving hole formed in a table T as a fixing table. The housing 1 includes an upper wall (distal end wall) 1a, a lower block 1b constituting a lower wall (base end wall), and a main body portion 1 c. The support rod 2 is inserted into the housing 1 so as to be movable in the vertical direction (the distal end side and the proximal end side in the axial direction). A press bolt 3 that abuts against the workpiece W is provided at an upper portion of the support rod 2.

A clamping and fixing region R is provided in the lower half of the outer peripheral surface of the support rod 2, and a tubular chuck 5 is fitted outside the clamping and fixing region R. The collet 5 has a tapered outer peripheral surface 5a whose upper portion is narrowed, and is elastically narrowed by 1 slit 5b extending in the up-down direction. An annular transmission member 6 is disposed on the outer peripheral side of the chuck 5, and a tapered inner peripheral surface 6a of the transmission member 6 faces the tapered outer peripheral surface 5a of the chuck 5 from above. A plurality of balls 8 are inserted into an annular tapered gap 7 formed between the tapered outer peripheral surface 5a and the tapered inner peripheral surface 6 a.

The first cylinder 10 for operation includes: a first cylinder hole (cylinder hole) 11 formed in the main body portion 1c of the housing 1; a ring-shaped first piston (piston) 12 inserted between the first cylinder hole 11 and the transmission member 6; a working chamber 13 for lowering the first piston 12; and a first spring 14 for raising the first piston 12. The first spring 14 is mounted in a spring chamber 15 formed on the lower side of the transmission member 6.

More specifically, the upper portion of the first piston 12 is guided to the upper wall 1a in a sealed manner by the seal member 16, and the lower portion of the first piston 12 is guided to the lower block 1b in a sealed manner by the other seal member 17. Then, by supplying compressed air to the working chamber 13, a downward force acts on a large-area annular pressure receiving surface formed at the upper end of the first piston 12, and an upward force acts on a small-area annular pressure receiving surface formed at the lower end of the first piston 12, so that the first piston 12 is lowered by the above-described difference in pressure between the upper and lower sides.

The first spring 14 is a compression coil spring, and is mounted between an upper spring seat 19 mounted on the lower surface of the driver 6 and a lower spring seat 20 mounted on the lower end of the collet 5. In addition, the upper spring seat 19 receives the plurality of balls 8. Further, the urging force of the first spring 14 causes the lower end of the collet 5 to abut against the lower block 1b via the lower spring seat 20.

A second cylinder 21 for advancing and retreating is provided in the lower block 1 b. The second cylinder 21 is configured as follows. In the lower block 1b, the second cylinder bore 22 of large diameter and the rod bore 23 of small diameter are connected in series upward. The second piston 25 of the output member 24 is inserted into the second cylinder hole 22 via a seal member 25a in a sealed state, and the piston rod 26 of the output member 24 is inserted into the rod hole 23. In the present embodiment, the second piston 25 and the piston rod 26 are separately configured, but they may be integrally configured.

The lower wall 30 of the second cylinder bore 22 is formed by the bottom wall of the housing hole, and an inlet chamber 31 is formed between the lower wall 30 and the second piston 25. A supply/discharge port 32 for compressed air communicates with the inlet chamber 31. Further, an outlet chamber 35 is formed between the upper wall 34 of the second cylinder bore 22 and the second piston 25. A second spring 36 for retracting the second piston 25 downward is installed between the upper wall of the rod hole 23 and the piston rod 26. In the present embodiment, the second spring 36 is formed of a compression coil spring. In the present embodiment, the driving means for moving the output member 24 upward is composed of the inlet chamber 31 and the compressed air supplied to the inlet chamber 31. The driving means for moving the output member 24 downward is constituted by the second spring 36.

A flange portion 42 is formed at the distal end portion of the piston rod 26, and the flange portion 42 engages with the operated portion 2a of the support lever 2 from above. An entry spring (urging member) 43 that urges the support rod 2 upward is attached between the flange portion 42 of the piston rod 26 and the pressure bolt 3. In the present embodiment, the intake spring 43 is formed of a compression coil spring.

Further, a switching member 48 is provided to communicate the working chamber 13 to one of the inlet chamber 31 and the outlet chamber 35. More specifically, a communication hole 49 is formed between the working chamber 13 and an upper portion of the second cylinder bore 22. The opening of the communication hole 49 and the outer peripheral surface of the second piston 25 constitute a switching member 48.

The operation of the work holder will be described with reference to fig. 1 and 2. In the released state shown in fig. 1, the first piston 12 and the driver 6 are lifted by the first spring 14, and the reduction in diameter of the collet 5 is thereby released. In addition, the second piston 25 and the piston rod 26 are lowered by the second spring 36. Thereby, the flange portion 42 of the piston rod 26 lowers the support rod 2 against the entry spring 43.

Here, the output member 24 of the present embodiment is movable from the lower limit position (the limit position on the base end side) shown in fig. 1 to the upper limit position (the limit position on the tip end side) shown in fig. 2, and the movable stroke S of the output member 24 is shown in fig. 1. In the released state of the work holder shown in fig. 1, the distance from the engaging portion 70 of the output member 24 located at the lower limit position (the limit position on the base end side) to the engaging portion 71 of the hold-down bolt 3 attached to the support rod 2 located at the lower limit position (the limit position on the base end side) is denoted by H in fig. 1. The movable stroke S of the output member 24 is set longer than the distance H from the engaging portion 70 to the locking portion 71. The pressure bolt 3 is a member constituting a part of the support rod 2.

In the released state, the workpiece W is carried horizontally to a position above the hold-down bolt 3.

When the work holder is driven from the release state of fig. 1 to the lock state of fig. 2, compressed air is supplied from the supply/discharge port 32 to the inlet chamber 31. Then, first, the compressed air in the inlet chamber 31 raises the second piston 25 and the piston rod 26 against the second spring 36. Subsequently, the flange portion 42 of the piston rod 26 raises the support rod 2 via the entry spring 43 and the hold-down bolt 3. Then, the upper end surface of the pressure bolt 3 abuts on the workpiece W. In this state, a gap is formed in the vertical direction between the lower surface of the flange portion 42 of the piston rod 26 and the operated portion 2a of the support lever 2, and a contact gap is also formed in the vertical direction between the upper end surface of the piston rod 26 and the lower end surface of the pressure bolt 3.

Then, the seal member 25a of the second piston 25 passes through the communication hole 49 by the movement of the second piston 25 to the upper limit position. Then, the compressed air at the supply/discharge port 32 passes through the inlet chamber 31 and the communication hole 49 in this order and is supplied to the working chamber 13. When the pressure in the working chamber 13 exceeds a predetermined set pressure, a pressure difference in the vertical direction of the air pressure acting from the working chamber 13 to the first piston 12 acts on the transmission element 6. When the driver 6 moves downward due to the downward pressure difference, the tapered inner circumferential surface 6a of the driver 6 smoothly engages with the tapered outer circumferential surface 5a of the collet 5 while rolling the balls 8, thereby reducing the diameter of the collet 5. Thereby, the reduced diameter collet 5 presses the outer peripheral surface of the support rod 2 toward the axial center, and locks (clamps and fixes) the support rod 2 at the height position shown in fig. 2. The upper surface of the workpiece W is machined in the locked state, and the downward force during the machining is strongly received from below by the supporting force of the support rod 2.

After the machining is completed, the compressed air in the inlet chamber 31 is discharged. Then, first, the second piston 25 and the piston rod 26 are lowered, and the flange portion 42 of the piston rod 26 is brought into contact with the operated portion 2a of the support lever 2 in the locked state from above. Therefore, the flange portion 42 reliably prevents the support rod 2 from being raised by the entry spring 43, and thereafter, the locked state of the support rod 2 is released. More specifically, the following is described below.

By the above-described discharge of the compressed air, first, the second piston 25 and the piston rod 26 are lowered by the second spring 36. Next, the compressed air in the working chamber 13 is discharged to the outside through the communication hole 49, the outlet chamber 35, the rod hole 23, the cylindrical hole of the support rod 2, the communication groove 45 formed between the lower wall 1b and the lower surface of the support rod 2, the spring chamber 15, and the vertical hole 46 formed in the lower wall in the up-down direction. When the pressure in the working chamber 13 is lower than the predetermined set pressure, the first piston 12 and the actuator 6 are pressed upward by the first spring 14, and the tapered inner circumferential surface 6a of the actuator 6 smoothly moves upward while rolling the balls 8, thereby releasing the pressed state of the tapered outer circumferential surface 5a of the chuck 5. Thereby, the clip 5 is expanded in diameter by its own elastic restoring force, and the locked state of the support rod 2 is released. Therefore, the second piston 25 and the piston rod 26 are further lowered, and the support rod 2 is returned to the lowered position of fig. 1.

The workpiece holder operates in the following manner in an abnormal state as described below.

In the released state, chips, cutting oil, or the like may accumulate between the upper wall 1a of the work holder and the support rod 2, and the sliding resistance of the support rod 2 with respect to the housing 1 may increase due to aging, thereby causing the upper wall 1a and the outer peripheral wall of the support rod 2 to adhere to each other (abnormal state). In this abnormal state, in the above-described conventional work holder, even if the second piston presses the support rod upward via the piston rod and the entry spring, the support rod cannot be raised due to the above-described adhesion.

In the work rest of the present embodiment, when the lock driving is performed in the abnormal state, if the compressed air is supplied from the supply/discharge port 32 to the inlet chamber 31, the compressed air in the inlet chamber 31 raises the second piston 25 against the biasing force of the second spring 36. At this time, the support bar 2 is adhered to the upper wall 1a of the housing 1, and the upward movement of the support bar 2 is restricted. Next, the engagement portion 70 formed at the upper portion of the piston rod 26 collides with the locking portion 71 formed at the lower end portion of the pressure bolt 3. Thus, the impact force or pressing force of the collision acts on the support rod 2 via the hold-down bolt 3, and then the piston rod 26 pushes up (in the present embodiment) the support rod 2 by about 0.2 mm. As a result, the adhesion state of the support bar 2 to the upper wall 1 is released. Subsequently, the support rod 2 is raised by the spring force of the entry spring 43, and the upper end surface of the hold-down bolt 3 is brought into contact with the lower end surface of the workpiece W. Thereafter, as described above, the first piston 12 locks (clamps and fixes) the support rod 2 at a predetermined height position via the collet 5. The distance (push-up amount) by which the piston rod 26 pushes up the support rod 2 is not limited to about 0.2mm, and may be, for example, 0.2mm to 0.5 mm. In this case, the distance from the upper end surface of the pressure bolt 3 in the released state to the lower surface of the workpiece W is set to be longer than the push-up amount. That is, the distance from the distal end surface of the support rod 2 in the released state to the workpiece W carried into the distal end direction position of the support rod 2 is set to be longer than the distance by which the output member 24 moves the support rod 2 toward the distal end side by the engaging portion 70. Thus, while the piston rod 26 is pushing up the support rod 2, the upper end surface of the support rod 2 (the upper end surface of the pressure bolt 3 constituting a part of the support rod 2) does not contact the lower surface of the workpiece W, and the piston rod 26 can be prevented from directly pushing up the workpiece W via the support rod 2.

The first embodiment described above exerts the following advantages.

When the support rod 2 is in a stuck state in which it is stuck to the upper wall 1a of the housing 1 in the released state of the work holder, the output member 24 is moved upward, and the engaging portion 70 of the output member 24 is brought into collision with the engaging portion 71 of the support rod 2, whereby the stuck state of the support rod 2 and the housing 1 is reliably released. In the present embodiment, the output rod 24 can abut against the support rod 2 located at the lower limit position between the vicinity of the upper limit position slightly below the upper limit position and the upper limit position. The output lever 24 is configured so as not to be able to abut against the support lever 2 when the support lever is moved slightly upward from the release position (lower limit position) shown in fig. 1. Therefore, the entry spring 43 has a biasing force to overcome the weight of the support rod, the frictional resistance, and the like, as in the conventional entry spring, but the entry spring 43 having a biasing force to such an extent that the workpiece is not lifted from the mounting table can be used.

Fig. 4, 5A and 5B, and 6A and 6B show second to fourth embodiments of the present invention. In the second to fourth embodiments, members having the same structure as that of the first embodiment are denoted by the same reference numerals in principle, and a structure different from that of the first embodiment will be described.

The second embodiment shown in fig. 4 differs from the first embodiment in the following point.

A cylindrical collet 5 is fitted around the outer peripheral surface of the support rod 2 inserted into the housing 1. The collet 5 of the present embodiment is pressed against the lower block 1b by the elastic body 51 made of rubber. Instead of rubber, the elastic body 51 may be formed of a spring member such as a wave washer, a disc spring, or a coil spring.

A second cylinder 21 for advancing and retreating is provided in the lower portion of the housing 1. The second cylinder 21 is configured as follows.

A second cylinder hole 22 is formed in the lower block 1b of the housing 1, and a second piston 25 is sealingly inserted into the second cylinder hole 22. A piston rod 26 protrudes upward from the second piston 25, and the piston rod 26 is inserted into a cylindrical hole of the support rod 2. The second working chamber 52 formed below the second piston 25 can communicate with the first working chamber 13 via a communication passage 53. Further, the throttle passage 54 is formed by an annular gap formed between the inner peripheral surface of the first cylinder bore 11 and the outer peripheral surface of the first piston 12. The second piston 25 and the piston rod 26 constitute an output member 24.

When the work holder is in the released state, the pressure oil is discharged from the second working chamber 52. Therefore, the first piston 12 is lifted by the first spring 14 to release the diameter reduction of the collet 5. In addition, the second piston 25 and the piston rod 26 are lowered by the second spring 36. Thereby, the flange portion 42 lowers the support rod 2. Further, compressed air (working pressure fluid) is supplied to the spring chamber (working chamber) 15 through a supply passage 46 formed in the lower wall 1b of the housing 1. The compressed air in the spring chamber 15 biases the support rod 2 upward. In the present embodiment, the biasing member that biases the support lever 2 upward with respect to the housing 1 is composed of the spring chamber 15 and compressed air supplied to the spring chamber 15.

When the work holder is operated from the release state to the lock state, the work W is carried horizontally to a position above the hold-down bolt 3. Then, the pressure oil of the pressure oil source is supplied to the second working chamber 52 through the supply/discharge port 32. Then, when the second piston 25 and the piston rod 26 rise against the second spring 36 due to the pressure oil in the second working chamber 52, the flange portion 42 of the piston rod 26 is separated upward from the operated portion 2a of the support rod 2. Then, the compressed air supplied to the spring chamber 15 moves the support rod 2 upward. Next, the pressure bolt 3 abuts against the workpiece W. In this state, a contact gap is formed in the vertical direction between the flange portion 42 of the piston rod 26 and the operated portion 2a of the support rod 2.

Then, the pressure oil of the second working chamber 52 is slowly supplied to the first working chamber 13 through the communication passage 53. When the pressure of the first working chamber 13 is insufficient (lower than a predetermined pressure), the first piston 12 is held at the upper limit position by the upward urging force of the first spring 14. Then, when the pressure of the first working chamber 13 exceeds a predetermined pressure, the pressure difference in the vertical direction of the pressure acting from the first working chamber 13 on the first piston 12 overcomes the upward urging force of the first spring 14, and the first piston 12 is moved downward. Then, the tapered inner peripheral surface 6a of the first piston 12 smoothly engages with the tapered outer peripheral surface 5a of the collet 5 while rolling the balls 8, thereby reducing the diameter of the collet 5. Thus, the reduced diameter collet 5 presses the outer peripheral surface of the support rod 2 radially inward, and clamps and fixes the support rod 2 at a predetermined height position. In this locked state, the upper surface of the workpiece W is machined, and the support rod 2 receives a downward force during the machining and receives a strong external force acting in the vertical direction. In the present embodiment, the predetermined height position of the support lever 2 is set to be higher (the distal end side) than the height position at which the engaging portion 70 of the output member 24 and the locking portion 71 of the support lever 2 can abut against each other. That is, a gap is formed between the locking portion 71 of the support rod 2 and the engaging portion 70 of the output member 24 when supporting the workpiece W. This prevents the output member 24 from lifting the workpiece W from the mounting table via the support rod 2, and as a result, prevents the machining accuracy of the workpiece W from being deteriorated.

When the work holder is operated from the locked state to the released state, the pressure oil in the second working chamber 52 is discharged to the outside after the completion of the machining. Then, first, the first spring 14 presses the first piston 12 upward, and the tapered inner peripheral surface 6a of the first piston 12 smoothly moves upward while rolling the balls 8, thereby releasing the pressed state of the tapered outer peripheral surface 5a of the cartridge 5. Thereby, the clip 5 is expanded in diameter by its own elastic restoring force, and the locked state of the support rod 2 is released. At substantially the same time, the second spring 36 lowers the second piston 25, and the flange portion 42 lowers the support rod 2.

The work holder operates in the following manner in the abnormal state shown in fig. 4.

In the released state, chips, cutting oil, or the like may accumulate between the upper wall 1a of the work holder and the support rod 2, and the upper wall 1a and the outer peripheral wall of the support rod 2 may adhere (abnormal state).

In the abnormal state, when the pressure oil is supplied from the supply/discharge port 32 to the second working chamber 52 when the work holder of the present embodiment is driven to be locked, the pressure oil in the second working chamber 52 overcomes the biasing force of the second spring 36 and raises the second piston 25. At this time, the support bar 2 is adhered to the upper wall 1a of the housing 1, and the vertical movement is restricted. Next, the engaging portion 70 of the stopper 72 formed on the piston rod 26 collides with the locking portion 71 formed on the operated portion 2a of the support rod 2. Thereby, the piston rod 26 directly strongly pushes up the support rod 2. As a result, the adhesion state of the support bar 2 to the upper wall 1a is released. Then, the support rod 2 is raised by the upward urging force of the compressed air in the spring chamber 15, and the upper end surface of the pressure bolt 3 is brought into contact with the lower end surface of the workpiece W. Thereafter, the first piston 12 clamps and fixes the support rod 2 at a predetermined height position via the clamp 5, as in the first embodiment described above.

The third embodiment shown in fig. 5A and 5B is different from the first embodiment in the following point.

A cylindrical center member 56 is provided at the center of the lower part of the housing 1 of the work holder so as to face upward, and a lower flange 56a of the center member 56 is pressed and fixed to the housing 1 by a lower block 1 b.

The support rod 2 is supported by the housing 1 so as to be movable in the vertical direction. A cylindrical member 57 is screwed to the upper end of the support rod 2. The lower half of the support rod 2 is fitted to the center member 56 with a predetermined gap. The gap constitutes a part of an air flow path 58 described later.

The second piston 25 is inserted in a sealed manner into the cylindrical hole of the center member 56.

A supply/discharge port 32 for supplying and discharging compressed air is formed in the table T, and the supply/discharge port 32 communicates with the working chamber 52 through a communication passage 53. The flow passage 73 branched at the middle portion of the communication passage 53 communicates with the first working chamber 13. The flow path 73 is provided with a throttle portion 74.

An air supply port 59 for supplying compressed air is provided in the upper right portion of the housing 2. Further, the valve member 61 is inserted into the cylindrical hole of the cylindrical member 57 so as to be movable in the vertical direction. An outlet passage 60 is formed between the outer peripheral wall of the valve member 61 and the cylindrical hole and the upper end surface of the cylindrical member 57. A groove-like communication passage 62 constituting a part of the outlet passage 60 is formed in the outer peripheral wall of the rod portion 61a of the valve member 61 in the vertical direction. Further, an outer periphery of a diameter-enlarged portion 61b provided at an upper portion of the valve member 61 protrudes downward, and a downward valve face 63 is formed at the downward protruding portion thereof. Correspondingly, a valve seat 64 is provided at the upper end of the cylindrical member 57.

The valve member 61 is pushed downward by its own weight, and is switched to an open position upward against its own weight by the air pressure in the pressure chamber 65 below the enlarged diameter portion 61 b. In the open position shown in fig. 5B, a gap having an annular shape in plan view is formed between the valve surface 63 and the valve seat 64. When the support rod 2 is raised and the valve member 61 is brought into contact with the workpiece W, the valve surface 63 of the valve member 61 is brought into contact with the valve seat 64 of the cylindrical member 57, and the air flow path 58 is blocked. This increases the pressure in the air flow path 58, and the pressure switch detects the increased pressure. As a result, it was confirmed that the valve member 61 was raised to a position abutting against the lower surface of the workpiece W. The cylindrical member 57 and the valve member 61 constitute a part of the support rod 2.

The air supply port 59 and the outlet passage 60 communicate with each other through the air flow passage 58. In the present embodiment, the air flow path 58 includes an inclined path 66 at the upper right portion of the housing 1, the spring chamber 15, the slit 5b of the clip 5, the outer peripheral space and the lower side space of the lower end portion of the support rod 2, a gap 67 formed between the inner peripheral surface of the lower half portion of the support rod 2 and the outer peripheral surface of the center member 56, a vertical groove 68 provided in the operated portion 2a of the support rod 2, and a cylindrical hole of the support rod 2.

The work holder according to the third embodiment operates in the following manner in an abnormal state described below.

In the released state shown in fig. 5A, the upper wall 1a of the work holder and the support rod 2 may be stuck due to chips, cutting oil, or the like (abnormal state). In this abnormal state, when compressed air is supplied from the supply/discharge port 32 to the working chamber 52 during the lock driving of the work holder, the compressed air in the working chamber 52 overcomes the biasing force of the second spring 36 to raise the second piston 25. At this time, the support bar 2 is adhered to the upper wall 1a of the housing 1, and the vertical movement is restricted. Subsequently, the engagement portion 70 of the piston rod 26 pushes up the locking portion 71 of the valve member 61. Then, the flange portion 75 formed at the lower end of the valve member 61 collides with the lower end surface of the cylindrical member 57. The adhesion between the upper wall 1a and the support rod 2 is released by the impact or pressing force of the collision. Then, the support rod 2 is raised by the spring force of the entry spring 43. At this time, the pressure of the pressure chamber 65 is increased by the compressed air supplied from the compressed air source to the outlet passage 60 through the air flow passage 58, and the air pressure of the pressure chamber 65 lifts the valve member 61 upward from the cylindrical member 57 to open the valve. Next, the upper end surface of the valve member 61 abuts against the lower end surface of the workpiece W. Next, the valve seat 64 of the cylindrical member 57 abuts against the valve seat 63 of the valve member 61 to close the valve. At this time, the pressure in the flow path 58 rises, and the rising pressure thereof is detected by a pressure switch (not shown), thereby reliably detecting that the valve member 61 is in contact with the lower surface of the workpiece W. Thereafter, the first piston 12 clamps and fixes the support rod 2 at a predetermined height position via the chuck 5. The second piston 25 and the piston rod 26 constitute an output member 24.

The fourth embodiment shown in fig. 6A and 6B is different from the first embodiment in the following point.

As shown in fig. 6A, an entry spring (urging member) 43 that urges the support rod 2 upward is attached between the flange portion 42 of the piston rod 26 and the pressure bolt 3. Here, the intake spring 43 is formed of a compression coil spring. As shown in fig. 6B, when the entry spring 43 is compressed to the maximum, the adjacent windings of the entry spring 43 are brought into close contact with each other. In the lower limit position shown in fig. 6A, when the support rod 2 is in a stuck state stuck to the housing 1 due to some abnormality, the output member 24 moves from the lower side (base end side) to the upper side (tip end side), and the output member 24 presses the support rod 2 from the lower side via the entry spring 43 in the stuck state to release the stuck state.

The above embodiment can be modified as follows.

The driving member of the first embodiment may be constituted by the inlet chamber 31 and another pressure fluid supplied to the inlet chamber 31, instead of the inlet chamber 31 and the compressed air supplied to the inlet chamber 31. The driving means for moving the output member 24 downward may be an elastic body such as rubber instead of the second spring 36 shown in the example, or may be compressed air.

Instead of the plurality of balls 8, a cylindrical member having a low friction function may be used.

The switching member 48 of the first and fourth embodiments may be configured to switch and communicate the working chamber 13 between the inlet chamber 31 and the outlet chamber 35. Therefore, there is no problem even when there is a moment when the outer peripheral surface of the second piston 25 completely closes the opening portion of the communication hole 49, or even when there is a moment when the communication hole 49 communicates with both the inlet chamber 31 and the outlet chamber 35. It is needless to say that the switching member 48 is not limited to the combination of the opening of the communication hole 49 and the outer peripheral surface of the second piston 25.

Further, a throttle passage may be provided in the communication hole 49 of the first embodiment, and instead of or in addition to the throttle passage, it is preferable to set the annular gap between the first cylinder bore 11 and the first piston 12 to a small value. In this case, since the annular gap and the flow resistance of the communication hole 49 increase, the pressure rise time and the pressure fall time of the working chamber 13 become longer. This delays the start of the descent and the start of the ascent of the first piston 12. This makes it possible to delay the start of locking and the start of unlocking the support rod 2 by the first piston 12, and therefore, it is possible to reliably lock and unlock the support rod 2 after the piston rod 26 has ascended and descended.

In addition, the present invention can be applied to a work holder of another structure instead of being applied to a work holder of the illustrated structure, and can also be applied to a use different from that of the work holder. For example, instead of the tapered transmission mechanism using the collet 5, it is conceivable to form an annular gas working chamber on the outer periphery of the thin sleeve, and to reduce the diameter of the thin sleeve by using pressure gas to lock the support rod or the like.

The outlet passage 60 is not limited to the illustrated structure as long as it is a passage that communicates the internal space of the support bar 2 with the outside.

In addition, the barrel member 57 may be omitted from the support rod 2. In this case, the valve member 61 constituting the support rod 2 is directly supported by the support rod 2.

The valve member 61 may be omitted from the support rod 2, and the outlet passage 60 formed to have a small diameter may be opened directly in the upper end surface of the support rod 2. In this case, when the upper end surface of the support rod 2 abuts against the workpiece W, the opening of the outlet passage 60 is closed and the outlet passage 60 is closed.

Description of reference numerals

1: a housing; 1 a: an upper wall (top end wall); 1 b: a lower wall (base end wall); 2: a support bar; 5: a chuck; 11: a cylinder bore; 12: a first piston (piston); 15: a spring chamber (working chamber); 24: an output member; 43: entering a spring; 70: a fastening part; 71: a locking portion.

Claims

1. A workpiece support is characterized in that,

The workpiece holder has:

a support rod (2) inserted into the distal end wall (1a) of the casing (1) so as to be movable to the distal end side and the proximal end side in the axial direction in the casing (1);

An annular collet (5) is embedded on the outer periphery of the support rod (2);

A piston (12) is inserted into a cylinder hole (11) axially formed in the housing (1), and driven by the piston (12), the support rod (11) is moved through the chuck (5). 2) lock;

an output member (24) inserted into the base end wall (1b) of the housing (1) in an axially movable manner; and

a force applying part for applying force to separate the support rod (2) from the output member (24),

When the support rod (2) at the extreme position on the base end side is in a sticking state to the housing (1) due to some abnormality, the output member (24) is sent from the base end through the output member (24). The end side moves to the distal end side, and the engaging portion (70) formed on the output member (24) pushes the engaging portion (71) formed on the support rod (2) from the proximal end side to thereby press the engaging portion (71) formed on the support rod (2) from the proximal end side. to release the sticking state,

The distance from the distal end surface of the support rod (2) in the released state to the workpiece (W) carried in to the position in the distal direction of the support rod (2) is set to be greater than the use of the output member (24). The engaging portion (70) has a long distance for moving the support rod (2) to the distal end side.

2. The workpiece holder according to claim 1, characterized in that,

The movable stroke (S) from the limit position on the proximal end side of the output member (24) to the limit position on the distal end side is set to be greater than that from the limit position on the proximal end side. The distance (H) from the engagement portion (70) of the output member (24) to the engagement portion (71) of the support rod (2) at the limit position on the proximal end side is long.

3. The workpiece holder according to claim 1 or 2, characterized in that,

The urging member includes a working chamber (15) formed on the base end side of the support rod (2) and a working pressure fluid supplied to the working chamber (15).

4. The workpiece holder according to claim 1 or 2, characterized in that,

The urging member consists of an entry spring (43) installed between the support rod (2) and the output member (24).

5. A workpiece support, characterized in that,

The workpiece holder has:

An entry spring (43) is installed between the support rod (2) and the output member (24) and applies force to separate the support rod (2) from the output member (24) ,

When the entry spring (43) is compressed to the maximum, the adjacent windings of the entry spring (43) are in a state of close contact with each other,

When the support rod (2) at the extreme position on the base end side is in a sticking state to the housing (1) due to some abnormality, the output member (24) is sent from the base end through the output member (24). The end side moves toward the distal end side, and the output member (24) pushes the support rod (2) from the base end side via the entering spring (43) in the close contact state to release the adhesion state.