JP2003039262A - Swing clamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance operation velocity of a swing clamp. SOLUTION: A clamp rod 5 is inserted movably in the vertical direction into a cylinder hole 4 of a housing 3. A sleeve 27 for revolving operation is inserted into an annular space between the clamp rod 5 and the cylinder hole 4. The sleeve 27 is pressed upward by a press spring 31, and at the same time, the upward movement of the sleeve 27 more than a prescribed amount is prevented by a stop means 32. A transduction mechanism 34 is provided extendedly from the clamp rod 5 to the sleeve 27, and the movement of the clamp rod 5 in the axial center direction against the sleeve 27 is transduced to the revolving motion around the axial center of the clamp rod 5 by the transduction mechanism 34. A torque limiter 51 provided with a straightly advancing guide part 52 and an engaging tool 53 is provided between the peripheral wall 4a of the cylinder hole 4 and the sleeve 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing clamp, and more particularly to a swing clamp provided with a torque limiter.

[0002]

2. Description of the Related Art A swing clamp with a torque limiter of this type has hitherto been a U.S. Pat. S. P. 4,351,51
There is one described in 6. The conventional technique is configured as follows. A cylindrical piston is inserted into the housing, and a clamp arm is fixed to the upper part of a piston rod protruding upward from the piston. The upper part of the operation rod is inserted into the cylindrical hole of the piston from below, and the guide ball provided on the piston is fitted into the control groove provided on the operation rod. When the piston is lowered during clamping, the piston (and the arm)
First descends while turning along the spiral groove portion of the control groove, and then goes straight down along the linear groove portion of the control groove.

A torque limiter is provided between the lower part of the operating rod and the lower part of the housing. The torque limiter is composed of a locking hole provided in the lower portion of the operation rod, a lock ball that engages with the locking hole, and a lock spring that presses the lock ball into the locking hole. . When the torque acting on the operating rod from the piston exceeds a set value for some reason, the tangential force acting on the peripheral surface of the operating rod overcomes the locking force of the lock ball, and Allow the operating rod to pivot. This allows
The control groove of the operating rod and the guide balls are prevented from being damaged.

[0004]

However, in the above-mentioned conventional technique, there is a problem that the operation speed of the swing clamp is slow. More specifically, it is as follows. When the swing speed of the piston is increased in order to increase the operation speed of the swing clamp, the inertial force of the piston and the arm becomes extremely large at the end of the swing, and an excessive torque acts on the operating rod. However, in the above-mentioned conventional technique, the outer diameter of the operating rod is small and the arm length thereof is short, so that the lock torque by the lock ball is small. For this reason, the locked state of the lock ball is easily released by the excessive torque at the end of turning described above. As a result, the piston and the arm cannot be turned in the next step. An object of the present invention is to make it possible to increase the operation speed of the swing clamp.

[0005]

In order to achieve the above object, the invention of claim 1 is, for example, shown in FIGS. 1 to 3 and 4A.
And, as shown in FIG. 4B, the swing clamp was configured as follows. Clamp rod 5 in cylinder hole 4 of housing 3
Is movably inserted in the axial direction. The clamp rod 5 is reciprocated in the axial direction by the driving means D. A sleeve 27 for turning operation is inserted into an annular space between the clamp rod 5 and the cylindrical hole 4. The sleeve 27 is pressed by the pressing means 31 toward the first end wall 3a of the housing 3, and the sleeve 27 is pressed.
Is stopped by the stop means 32 from moving in the direction of the first end wall 3a by a predetermined amount or more. The conversion mechanism 34 extends over the clamp rod 5 and the sleeve 27.
By the conversion mechanism 34,
The movement of the clamp rod 5 in the axial direction with respect to the above is converted into a swiveling motion around the axial center of the clamp rod 5. A torque limiter 51 is provided between the sleeve 27 and the peripheral wall 4 a of the cylindrical hole 4. The torque limiter 51
The sleeve 27 is guided in the axial direction, and when the torque acting on the sleeve 27 from the clamp rod 5 via the conversion mechanism 34 does not exceed the set value, the sleeve 27 pivots with respect to the peripheral wall 4a. When the torque exceeds the set value, the sleeve 27 is allowed to rotate with respect to the peripheral wall 4a.

The invention of claim 1 has the following effects. Since the torque limiter is provided between the peripheral wall of the cylindrical hole of the housing and the sleeve inserted in the cylindrical hole, the radius between the lock portion (engagement tool) of the torque limiter and the axial center of the clamp rod. The size increases. Therefore, the torque limiter has a large arm length for locking and can secure a large lock torque. Therefore, even when a large torque acts on the sleeve from the clamp rod at the end of turning of the clamp rod, the torque limiter can be held in the connected state. as a result,
The swing speed of the clamp rod can be increased, and the operation speed of the swing clamp can be increased.

As shown in the invention of claim 2, it is preferable to add the following configuration to the invention of claim 1 described above. The torque limiter 51 includes the peripheral wall 4 of the cylindrical hole 4.
a) at least one straight guide portion 52 provided on the a so as to extend in the axial direction, and at least one engaging member 53 supported by the sleeve 27 so as to be movable in the radial direction and to prevent movement in the circumferential direction. And a biasing means F for engaging the engagement tool 53 with the straight-ahead guide portion 52 with a predetermined pressing force. The invention of claim 2 has an effect that the torque limiter can be made compact with a simple configuration because the number of parts of the torque limiter is small.

As shown in the invention of claim 3, it is preferable to add the following constitution to the invention of claim 2 described above. The straight guide portion 52 is constituted by a groove extending in the axial direction, and the engaging tool 53 is constituted by a wedge member whose height increases toward the outer side in the radial direction. The biasing means F formed of a spring is wedge-engaged with the sleeve 27, and is mounted between the second end wall 3b of the housing 3 and the engaging tool 53, and the biasing means F is biased. The engagement protrusion 53a of the engagement tool 53 is fitted into the groove-shaped straight guide portion 52 by the force. According to the third aspect of the present invention, the means for urging the engaging member can be mounted so as to extend in the axial direction of the housing. Therefore, the space in the housing can be effectively used to make the torque limiter more compact. Can be made.

According to the invention of claim 4, in the invention of claim 3, the pressing means 31 comprising a spring is used.
The pressing force of the sleeve 27 is applied to the sleeve 27 via the engagement tool 53.
When the pushing means 31 also serves as the biasing means F, the swing clamp can be made compact because a dedicated mounting space for the biasing means can be omitted.

According to the invention of claim 5, in the invention of claim 3 or 4, the straight-moving guide portion 52 is constituted by an arcuate groove, and the engaging projection 53a is formed in an arcuate shape. In this case, the torque limiter can be manufactured inexpensively with a simple structure.

According to the invention of claim 6, in any one of the inventions of claims 2 to 5, a plurality of the straight guide portions 52 and the engaging tools 53 are arranged at substantially equal intervals in the circumferential direction. In this case, the plurality of engaging members can support the clamp rod in a well-balanced manner via the sleeve, so that the operating accuracy of the torque limiter is improved.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
It will be described with reference to FIG. First, the structure of the swing clamp will be described with reference to FIGS. 1 to 3. FIG. 1 is a cross-sectional view of the swing clamp as viewed from an elevation. FIG. 2A is a development view of a main part of a conversion mechanism provided in the swing clamp in elevation view. FIG. 2B is a schematic diagram of FIG. 2A described above. FIG. 3 is an end view taken along the line III-III in FIG. 1 described above.

The housing 3 of the swing clamp 2 is fixed to the table 1 of the machine tool by a plurality of bolts (not shown). The clamp rod 5 is inserted into the cylindrical hole 4 of the housing 3. An arm 6 is projected outward from the upper end of the clamp rod 5 in the radial direction.
A push bolt 7 is fixed to the tip of the. The arm 6 is fitted to the tapered surface 8 of the clamp rod 5 and fixed at a predetermined turning position by a nut 9.

The upper end wall (first end wall) 3 of the above housing 3
The upper sliding portion 11 of the clamp rod 5 is slidably supported on a by a. Further, a guide cylinder 13 is provided on the lower end wall (second end wall) 3b of the same housing 3, and the lower slide portion 12 of the same clamp rod 5 is slidably supported by the guide cylinder 13.

The means D for driving the clamp rod 5 is constructed as follows. A piston 15 is fixed to the clamp rod 5 between the upper sliding portion 11 and the lower sliding portion 12, and the piston 15 is inserted into the cylindrical hole 4 in a hermetically sealed manner. In addition, here, the piston 15
Is formed integrally with the clamp rod 5, but instead of this, the piston 15 is replaced by the clamp rod 15
It is also possible to form it separately from.

A first chamber 21 for clamping is formed between the upper end wall 3a and the piston 15, and the first chamber 2 is formed.
The pressure oil can be supplied to and discharged from the pressure oil supply / discharge port 16 with respect to 1. Further, a second chamber 22 for unclamping is formed between the lower end wall 3b and the piston 15 as above. The second
The clamp rod 5 is biased upward by the unclamping spring 18 mounted in the chamber 22. here,
The unclamp spring 18 is used for the clamp rod 5
Is inserted into the hollow part 5a of the clamp rod 5, the upper end of the spring is in contact with the upper part of the clamp rod 5, and the lower end of the spring is received by the lower end wall 3b via the thrust bearing 19. In addition, the second chamber 22 is provided with
Communicates with the atmosphere. The trap valve 24 provided in the breathing path 23 is configured by an O-ring valve seat 24a, a ball valve member 24b, and a closing spring 24c.

A sleeve 27 for turning operation is inserted in an annular space between the outer peripheral surface of the clamp rod 5 and the cylindrical hole 4. The sleeve 27 is urged toward the upper end wall 3a by a pressing spring 31 which is a pressing means. The upward movement of the sleeve 27 by a predetermined amount or more causes stop means 32.
Blocked by. The stop means 32 is constituted by the stepped portion of the cylindrical hole 4 here.
A conversion mechanism 34 is provided over the outer peripheral surface of the clamp rod 5 and the inner peripheral surface of the sleeve 27. The conversion mechanism 34 converts the reciprocating motion of the clamp rod 5 in the axial direction into a revolving motion, and is configured as follows here.

As shown mainly in FIGS. 2A and 2B, the outer peripheral surface of the clamp rod 5 is formed with a first recessed passage 41 which communicates in a sawtooth shape over the entire outer peripheral surface. The first recess 41 is formed by a double-threaded first spiral groove 41.
While forming the a.41b by approximately one pitch, the end of the first spiral groove 41a on one side and the start end of the first spiral groove 41b on the other side are made to communicate by the communication groove 41c, and The terminal end and the starting end of the first spiral groove 41a on one side are communicated with each other by another communication groove 41d. In addition, the inner peripheral surface of the sleeve 27 has a second recessed passage 42 (see FIG. 1) communicating with the entire peripheral surface of the inner peripheral surface in the circumferential direction. The second recess 42 forms two second spiral grooves (not shown) corresponding to the first spiral grooves 41a and 41b at a predetermined interval in the circumferential direction, and the communication groove 41c.・ Two escape grooves 4 corresponding to 41d
2c is formed to extend in the circumferential direction. Note that FIG.
Then, one of the above two escape grooves, the escape groove 4
Only 2c is shown. Then, the above-mentioned first recess 41
A large number of rolling balls 43 are filled between the second concave path 42 and the second concave path 42.

A torque limiter 51 is provided between the peripheral wall 4a of the cylindrical hole 4 and the sleeve 27.
The torque limiter 51 prevents the sleeve 27 from rotating with respect to the peripheral wall 4a when the torque acting on the sleeve 27 from the clamp rod 5 via the conversion mechanism 34 does not exceed a set value. On the other hand, the torque limiter 51 allows the sleeve 27 to rotate with respect to the peripheral wall 4a when the torque exceeds the set value.

More specifically, the torque limiter 5 described above.
1 is configured as follows. Two straight guide portions 52, 52 are provided facing each other on the peripheral wall 4a of the cylindrical hole 4. Each straight guide portion 52 is formed by an arc groove extending in the axial direction. Two engaging tools 53, 53 that engage with the two straight guide portions 52, 52
Is inserted into the accommodation groove 55 of the sleeve 27. Each of the engaging members 53 is formed of a wedge-shaped member whose height increases toward the outer side in the radial direction, and is engaged with the tapered surface 56 of the accommodation groove 55 by taper engagement. As a result, the two engagement tools 53, 53 are supported by the sleeve 27 in a state where they can be moved in the radial direction and prevented from moving in the circumferential direction.

An annular spring receiver 58 is mounted on the lower surface of the above-described engaging members 53. The lower end of the pressing spring 31 is received by the lower end wall 3b of the housing 3, and the upper end of the pressing spring 31 is received by the spring receiver 58. As a result, the urging force of the pressing spring 31 presses the engagement tool 53 outward in the radial direction via the taper surface 56, and the engagement tool 53.
The arc-shaped engaging protrusion 53a is fitted into the straight-ahead guide portion 52. That is, here, the pressing spring 31 also serves as the urging means F for the engaging tool 53.

The swing clamp 2 operates as follows. In the retracted state of FIG. 1, the first chamber 2 for clamping described above.
1 pressure oil has been discharged, and the unclamping spring 1
The clamp rod 5 is moved upward by 8 and the sleeve 27 is in contact with the stop means 32 by the pressing spring 31.

When the swing clamp 2 in the retracted state shown in FIG. 1 is switched to the clamped state, the first chamber 2 described above is used.
Supply pressure oil to 1. Then, the piston 15 pushes down the clamp rod 5, and the clamp rod 5 descends while rotating clockwise in plan view with respect to the sleeve 27 which is prevented from rotating by the straight guide portion 52. I will do it. At the time of turning the clamp, the rolling balls 43 move to the first spiral grooves 41a and 41b.
And it circulates in the circumferential direction while rolling along the second spiral groove (not shown). Therefore, the frictional resistance at the time of turning the clamp is reduced, and the clamp rod 5 turns smoothly. Subsequently, the piston 15 moves the clamp rod 5 and the sleeve 27 into the straight guide portion 52.
Then, the clamp rod 5 is moved straight to the clamp position (not shown).

When the clamped state is switched to the retracted state shown in FIG. 1, the pressure oil in the first chamber 21 is discharged.
Then, the urging force of the unclamp spring 18 and the urging force of the push spring 31 cause the clamp rod 5 and the sleeve 27 to rise straight along the straight guide portion 52, and the sleeve 27 stops. It is received by means 32. Subsequently, the sleeve 27 is prevented from rising by the stop means 32.
On the other hand, the clamp rod 5 is moved upward by the urging force of the unclamp spring 18. As a result, the clamp rod 5 rises while turning counterclockwise in plan view and is switched to the retracted position in FIG. Even during this retracting turn, the rolling balls 43 circulate in the circumferential direction while rolling along the first spiral grooves 41a and 41b and the second spiral grooves (not shown). Therefore, the frictional resistance at the time of the retracting turn is reduced, and the clamp rod 5 turns smoothly.

Next, the operation of the torque limiter 51 will be described.
4A and 4B with reference to FIGS. 1 to 3 above.
Explained by. FIG. 4A shows the connection state of the torque limiter 51, and is an enlarged view of the main part of FIG. Further, FIG. 4B is a diagram similar to FIG. 4A described above, showing a cut state of the torque limiter.

When the torque acting on the sleeve 27 from the clamp rod 5 through the conversion mechanism 34 does not exceed the set value during the clamp turning or the retracting turning, the engagement of the engaging tool 53 is changed. Compound protrusion 53
The engagement lock force by the urging means F is larger than the tangential force acting on the outer peripheral surface of a. Therefore, as shown in FIG. 4A, the engagement protrusion 53a is kept fitted in the straight-ahead guide portion 52, and the sleeve 27 pivots with respect to the peripheral wall 4a of the cylindrical hole 4. Is prevented.

On the other hand, when the torque exceeds the set value for some reason, the tangential force acting on the outer peripheral surface of the engagement projection 53a causes the engagement lock by the urging means F. Greater than power. Therefore, as shown in FIG. 4B, the engagement tool 53 moves inward in the radial direction along the tapered surface 56 against the biasing means F, and the engagement projection 53a. The fitted state with the straight guide portion 52 is released, and the sleeve 27 is allowed to rotate with respect to the peripheral wall 4a. As a result, the excessive torque of the clamp rod 5 does not act on the conversion mechanism 34 or the sleeve 27. Therefore, due to the excessive torque, the conversion mechanism 34
It is possible to reliably prevent the structural members such as the rolling balls 43 from being damaged.

More specifically, when the swing clamp 2 is clamped or retracted, if the arm 6 is prevented from pivoting by another object such as a tool of a machine tool, an excessive torque is applied. Is the above conversion mechanism 3
Try to act on 4. However, even in this case, the connection state of the torque limiter 51 is released due to the excessive torque, so that the constituent members of the conversion mechanism 34 can be prevented from being damaged. When fixing the arm 6 to the clamp rod 5 during assembly of the swing clamp 2, first, the arm 6 is fitted on the tapered surface 8 of the clamp rod 5, and then the clamp rod 5 is mounted. A hexagon wrench is inserted into the hexagonal hole 5b to prevent the clamp rod 5 from turning, and the nut 9 is tightened in this state. If the nut 9 is strongly tightened while the turning of the clamp rod 5 is not blocked, excessive torque tends to act on the converting mechanism 34. However, also in this case, the connection state of the torque limiter 51 is released by the excessive torque, so that the constituent members of the conversion mechanism 34 can be reliably prevented from being damaged.
The same applies when removing the arm 6 from the clamp rod 5.

The above embodiment can be modified as follows. The straight guide portion 52 and the engagement tool 53.
Instead of arranging two, three or more may be arranged. In this case, it is preferable to dispose the straight guide portions 52 and the engaging tools 53 at substantially equal intervals in the circumferential direction. It should be noted that the straight guide portion 52 and the engaging tool 53 may be arranged one by one. Although the straight guide portion 52 is formed of a groove and the protrusion 53a is provided in the engagement lock portion of the engagement tool 53, instead of this, the straight guide portion 52 is formed of a protrusion and the above-mentioned engagement is performed. It is also possible to form the engagement lock portion of the fitting 53 with a groove. The means F for urging the engagement tool 53 outward in the radial direction is also replaced by the pressing spring 31, and instead of the pressing spring 31, another spring or another elastic body such as rubber is used. May be provided.

The pressing means of the conversion mechanism 34 may be constituted by another elastic body such as rubber instead of the illustrated pressing spring 31, and furthermore, a pressure fluid such as compressed air or pressure oil may be used. It is also possible to do so. The conversion mechanism 34 may be any mechanism that changes the movement of the clamp rod 5 in the axial direction to the turning movement of the clamp rod 5. The following mechanism is conceivable instead of the exemplified mechanism. One spiral groove is formed on the outer peripheral surface of the clamp rod 5 for one round, and the end and the start end of the spiral groove are communicated in the axial direction by the communication groove. Sleeve 2 fitted onto the clamp rod 5
On the inner peripheral surface of 7, another spiral groove corresponding to the above spiral groove and a relief groove corresponding to the above communication groove are formed. Then, the groove of the clamp rod 5 and the sleeve 27
A large number of rolling balls are filled between the grooves. Furthermore, the conversion mechanism 34 may be configured as follows. That is, a cam groove having a predetermined length is formed on the outer peripheral surface of the clamp rod 5, and an operating tool such as a ball attached to the sleeve 27 is fitted into the cam groove.

The fluid supplied to and discharged from the first chamber 21 for clamping may be a liquid such as another type of liquid or gas instead of pressure oil. In addition, the swing clamp 2 is
Instead of the clamp drive by the pressure fluid, the clamp drive by the spring force is also possible. Further, the swing clamp 2 may be a double-acting type instead of the single-acting type. That is, the unclamping second chamber 2
The pressure fluid can be supplied to and discharged from the second as well.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a cross-sectional view of a swing clamp as seen from an elevational view.

FIG. 2A is an elevational development view of a main part of a conversion mechanism provided in the swing clamp. FIG. 2B is a schematic diagram of FIG. 2A described above.

FIG. 3 is an end view taken along the line III-III in FIG. 1 described above.

FIG. 4A is an enlarged view of a main part of FIG. 1 showing a connected state of a torque limiter provided in the swing clamp. FIG. 4B is a diagram similar to FIG. 4A described above, showing a cut state of the torque limiter described above.

[Explanation of symbols]

3 ... Housing, 3a ... 1st end wall (upper end wall) of the housing 3, 3b ... 2nd end wall (lower end wall) of the housing 3, 4 ... Cylindrical hole, 4a ... Peripheral wall of the cylindrical hole 4, 5 ... Clamp rod, 27 ...
Sleeve, 31 ... Pressing means (pressing spring), 32 ... Stopping means, 34 ... Conversion mechanism, 51 ... Torque limiter, 52 ... Straight guide section, 53 ... Engaging tool, 53a ... Engaging projection, D ... Driving means, F … Biasing means.

Claims (6)

[Claims] 1. A clamp rod (5) is inserted into a cylindrical hole (4) of a housing (3) so as to be movable in the axial direction, and the clamp rod (5) is driven by the driving means (D) to the above-mentioned axial center. The clamp rod (5) and the cylindrical hole.
A sleeve (27) for turning operation is inserted into an annular space between (4) and the sleeve (27) is pushed toward the first end wall (3a) of the housing (3) by a pressing means (31). While pressing
The sleeve (27) is prevented from moving more than a predetermined amount in the direction of the first end wall (3a) by a stop means (32), and is converted between the clamp rod (5) and the sleeve (27). The mechanism (34) is provided, and the clamp rod for the sleeve (27) is provided by the conversion mechanism (34).
The movement of (5) in the axial direction is converted into a swiveling motion of the clamp rod (5) around the axial center, and the clamp rod (5) is moved between the peripheral wall (4a) of the cylindrical hole (4) and the sleeve (27). A torque limiter (51) is provided, and the torque limiter (51) guides the sleeve (27) in the axial direction, and the sleeve (27) through the conversion mechanism (34) from the clamp rod (5). ) Does not exceed the set value, the surrounding wall (4
It prevents the sleeve (27) from rotating with respect to (a) and allows the sleeve (27) to rotate with respect to the peripheral wall (4a) when the torque exceeds the set value. A swing clamp characterized by the following. 2. The swing clamp according to claim 1, wherein the torque limiter (51) is provided on the peripheral wall (4a) of the cylindrical hole (4) so as to extend in the axial direction. The guide part (52) and the sleeve (27) so as to be movable in the radial direction and to prevent the movement in the circumferential direction.
At least one engaging member (53) supported by the above-mentioned engaging member (53) by a predetermined pressing force.
A swing clamp comprising: a biasing means (F) for engaging with (52). 3. The swing clamp according to claim 2, wherein the rectilinear guide portion (52) is formed by a groove extending in the axial direction, and the engaging member (53) increases in height in a radially outward direction. Of the wedge member that increases the
(53) is wedge-engaged with the sleeve (27), and the biasing means (F) consisting of a spring is attached to the housing (3).
Mounted between the second end wall (3b) and the engaging member (53), and the engaging member (F) applies the urging force to the engaging member.
The engaging protrusion (53a) of (53) is provided with the above groove-shaped straight guide portion.
A swing clamp fitted to (52). 4. The swing clamp according to claim 3, wherein the pressing force of the pressing means (31) formed of a spring is transmitted to the sleeve (27) through the engaging tool (53), and the pressing means is transmitted. (31) A swing clamp which is also used as the biasing means (F). 5. The swing clamp according to claim 3, wherein the straight guide portion (52) is formed by an arcuate groove, and the engaging protrusion (53a) is formed in an arcuate shape. And swing clamp. 6. The swing clamp according to claim 2, wherein a plurality of the straight guide portions (52) and the engaging members (53) are arranged at substantially equal intervals in the circumferential direction. And swing clamp.