JP3354312B2 - Clamping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for clamping an object such as a mold or a workpiece by a balance-type clamp arm.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No.
There is one described in JP-A-221224. This device is configured as follows, as shown in FIG.

[0003] A clamping device 1 extending in the front-rear direction (the left-right direction in FIG. 6; the same applies hereinafter) on a fixed base 101 of a processing machine.
02 is fixed, and the mold D is placed on the front side of the housing 103 of the clamp device 102. The mold D can be pressed against the upper surface of the fixed base 101 by the clamp arm 105.

A fulcrum 105a is provided at an intermediate position in the front-rear direction of the clamp arm 105, and the fulcrum 105a is supported by the housing 103 so as to be vertically swingable. Further, a force point portion 105b is provided at a rear portion of the clamp arm 105.
That is, a roller insertion groove 117 is formed at the rear portion of the arm 105, and the upper pin 1 provided between both side walls of the roller insertion groove 117 is formed.
The first roller 121 is rotatably supported on the roller 18. The first of the above
A second roller 122 is attached to the housing 103 below the roller 121.
Is rotatably supported by the lower pin 119. A circular transmission rod 128 is inserted between the upper and lower rollers 121 and 122 to form a wedge surface 129 on the upper surface of the transmission rod 128. The transmission rod 128 described above is advanced and retracted by the piston rod 150 of the double-acting cylinder 106.

In the illustrated clamp state, the piston rod 150 is advanced leftward, and the transmission rod 128 is press-fitted between the first roller 121 and the second roller 122. Accordingly, the wedge surface 129 strongly presses the first roller 121 upward, and the action point portion 105c of the clamp arm 105 swings downward to strongly press the mold D. In the clamped state, a strong operating force acts on the outer peripheral surface of the first roller 121 from the wedge surface 129, and the first roller 12
A strong operation reaction force acts on the wedge surface 129 from the outer peripheral surface of the same.

[0006]

In the above-described conventional clamping device, the first roller 121 has a large diameter,
There is a problem that the clamp device 102 becomes large and heavy.

That is, a large surface pressure acts on the outer peripheral surface and the wedge surface 129 of the first roller 121 due to a strong operation force or operation reaction force at the time of clamping. These rollers 121 and wedge surfaces 129
In order to smoothly engage the wedge over a long period of time, it is necessary to minimize these surface pressures. Therefore, it is conceivable to increase the roller width of the first roller 121. However, the first roller 121 cannot be increased in roller width due to the groove width of the roller insertion groove 117, and the outer diameter must be increased in order to reduce the surface pressure.

However, if the outer diameter of the first roller 121 is increased, the first roller 121 interferes with the second roller 122.
In order to prevent this, the height of the housing 103 needs to be increased. As a result, the clamp device 102 becomes large and heavy.

[0009] As shown in FIG.
A guide groove 114 extending in the front-rear direction is formed in the guide groove 114, and the clamp arm 105 is supported in the guide groove 114 via a fulcrum pin 113, so that the clamp arm 105 can be advanced and retracted from the front surface of the housing 103. In such a case, the following problem newly arises.

That is, when the clamp arm 105 is advanced leftward from the retracted state to the advanced state, the clamp arm 105 may be stopped at a position in the middle of the advance. This halfway stop occurs when an error occurs in the thickness dimension of the fixed portion of the mold D, insufficient lubrication or rust of the sliding surface of the clamp arm 105, or foreign matter jamming on the sliding surface of the same. The sliding resistance increases due to the
Occurs when the bullet pressure exceeds 5.

Since the axes of the upper and lower rollers 121 and 122 are displaced in the horizontal direction in the drawing due to the stop of the clamp arm 105, a large eccentric moment acts on the transmission rod 128, and the eccentric moment causes the transmission rod 128 to move. 12
8 may be bent. An object of the present invention is to make a clamping device small and lightweight. Another object of the present invention is to prevent damage to the clamp device.

[0012]

According to the present invention, in order to achieve the above object, a clamping device is constructed as follows, for example, as shown in FIGS.

A clamp arm 5 supported by a housing 3 extending in the front-rear direction so as to be swingable up and down; a transmission shaft 20 moved in the front-rear direction by an output portion 6a of a driving means 6;
The first roller 21 is supported by a portion of the transmission shaft 20 near the center in the left-right direction and engages with the power point 5b of the clamp arm 5, and the first roller 21 is supported by both ends of the transmission shaft 20 near the left and right directions. And second rollers 22 guided in the front-rear direction by the housing 3.

The driving means 6 may be a hydraulic cylinder such as a pneumatic cylinder or a hydraulic cylinder, or a mechanism that advances and retreats by screwing a male screw and a female screw.

[0015]

The present invention operates, for example, mainly as shown in FIG. Fig. 4 (b)
4C is switched from the unclamped state to the clamped state shown in FIG.
0 is advanced forward (to the left in the figure) along the second rollers 22.

Then, as shown in FIG. 4C, first, the first roller 21 is advanced along the swing surface A of the clamp arm 5. Then, the first roller 21
However, the force point portion 5b swings upward in a state where the force point portion 5b is received by the housing 3 by the second roller 22, so that the action point portion 5c is swung downward by clamp and comes into contact with the upper surface of the mold D. Subsequently, when the first roller 21 is advanced along the tightening surface B of the clamp arm 5, the first roller 21 is received by the housing 3 by the second roller 22. The portion 5b is strongly swung upward, so that the action point portion 5c is
Press strongly.

[0017]

1 to 4 show an embodiment of the present invention. First, the configuration of the clamp device will be described with reference to FIGS. FIG. 1 is a longitudinal side view of the clamp device, FIG.
3 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along the line III-III in FIG.

A clamp device 2 extending in the front-rear direction (the left-right direction in FIG. 1; the same applies hereinafter) is mounted on a fixed base 1 of the injection molding machine. Housing 3 of the clamping device 2
Is fixed to the fixed base 1 by two bolts 4 (only one is shown here), and a mold D is fixed to the fixed base 1 by a clamp arm 5 projecting forward from the housing 3. Pressed to the top. The clamp arm 5 is driven by a pneumatic cylinder 6 which is a driving unit.

The housing 3 includes left and right (right and left in FIGS. 2 and 3, the same applies hereinafter) blocks 7.8, upper and lower blocks 9 and 10, and these four blocks 7.8.
-Consists of a plurality of bolts 11 for integrally fastening 9 and 10. The clamp arm 5 is inserted between the left and right blocks 7 and 8 so as to be movable in the front-rear direction and swingable in the vertical direction. Bolt holes 7a and 8a are vertically penetrated in the front portions of the left and right blocks 7.8.

A fulcrum 5a is provided at an intermediate portion of the clamp arm 5 in the front-rear direction, a power point 5b is provided at a rear portion of the arm 5, and an action point 5c is provided at a front portion of the arm 5. The fulcrum portion 5a is supported by the housing 3 by a fulcrum pin 13 extending in the left-right direction so as to be movable in the front-rear direction and swingable up and down.

More specifically, guide grooves 14 extending in the front-rear direction are formed on the inner surfaces of the left and right blocks 7 and 8, and the left and right ends of the fulcrum pin 13 are fitted into the respective guide grooves 14. You. The receiving surface 14a of the guide groove 14 is provided on the upward supporting flat surface 13a provided at the end of the pin.
Are faced from above. The left and right sliding bearings 15 are externally fitted to the center portion of the fulcrum pin 13 in the left-right direction, and the through holes 16 of the fulcrum 5a are externally fitted to these sliding bearings 15.

The power point portion 5b is connected to the output portion 6a of the pneumatic cylinder 6 via a first transmission roller 21 and a transmission shaft 20, and is vertically moved by the forward and backward movement of the output portion 6a. Swing operation in the direction.

More specifically, another sliding bearing 23 is externally fitted to the transmission shaft 20 extending in the left-right direction, and a connecting ring 24 is externally fitted to the center of the sliding bearing 23 in the left-right direction. 24 is fixed to the output unit 6a. The first rollers 21 are externally fitted to the left and right sides of the connection ring 24 at the center of the sliding bearing 23 in the left-right direction. These two first rollers 21
21 is engaged with the power point 5b from below. As shown in FIG. 1, the power point portion 5b is formed in a curved cam shape in a state where the swing surface A and the tightening surface B are connected.

Further, the second rollers 22 are externally fitted to the transmission shaft 20 near both ends in the left-right direction via needle roller bearings 25. Each second roller 22 is guided movably in the front-rear direction by support grooves 26 formed in the left and right blocks 7.8.

The cylinder part 34 of the pneumatic cylinder 6
Consists of front and rear end plates 35 and 36 and a cylinder tube 37, and the rear end plate 36 has four long bolts (not shown).
Is pressed toward the left and right blocks 7 and 8. A piston 40 is hermetically inserted into the cylinder tube 37. Reference numeral 41 denotes an O-ring, and reference numeral 42 denotes a plastic liner. Due to the self-lubricating action of the liner 42, the piston 40 is moved with a small force.

A clamp operation chamber 44 is formed between the piston 40 and the rear end plate 36, and a clamp state holding spring 45 is mounted in the clamp operation chamber 44.
An unclamping operation chamber 46 is formed between the piston 40 and the front end plate 35. 47 and 48
Are compressed air supply / discharge ports.

A piston rod 50 projecting forward from the piston 40 is hermetically inserted into the front end plate 35. Reference numeral 51 denotes an O-ring, and reference numeral 52 denotes a plastic liner. Due to the self-lubricating action of the liner 52, the piston rod 50 is moved with a light force.
The output section 6a is provided at the front end of the piston rod 50.

The front end plate 35 and the clamp arm 5
A forward spring 55 is mounted between the lower part and the lower part. Reference numeral 56 denotes a front spring receiver, and reference numeral 57 denotes a rear spring receiver. A retreating operating part 60 projecting upward from the connection ring 24 is provided on a retreating operated part 59 at a lower rear portion of the clamp arm 5.
Are engaged. Note that the arm 5 is urged clockwise around the fulcrum pin 13 by the urging force of the spring 55. Thereby, the point of force 5b of the arm 5
Presses the first roller 21, the transmission shaft 20, and the second roller 22 downward, so that the second roller 22 is always in contact with the lower wall of the support groove 26.

Further, the upper side of the clamp arm 5 is
It is covered by a cover plate 61 fixed to the upper block 9. An upper dust cover 62 is formed by the front bent portion of the cover plate 61. Also,
A lower dust cover 63 is fixed to the lower block 10. The left block 7 has a clamp state detection switch 66 and an unclamped state detection switch.
(Not shown) are provided before and after. These switches are
The position of the magnet 67 fixed to the left surface of the transmission shaft 20 is detected.

The clamp device 2 operates as follows, mainly as shown in FIG. FIG. 4A shows the retracted state, FIG. 4B shows the advanced state, and FIG. 4C shows the clamped state. 1A, the compressed air is discharged from the clamp working chamber 44 and the compressed air is supplied to the unclamping working chamber 46. As a result, the piston 40 and the piston rod 50 are moved rearward (to the right in the drawing), and the clamp arm 5 is switched to the retracted position X by the retracting operation section 60.

When the mold D is clamped by the clamp arm 5, the compressed air is discharged from the unclamping operation chamber 46 and the compressed air is supplied to the clamping operation chamber 44 so that the piston 40 and the piston rod 50 are moved forward. (Left side in the figure). With this, first,
The clamp arm 5 is moved forward along the guide groove 14 and the support groove 26 by the advance spring 55, and then the fulcrum pin 13 is moved forward of the guide groove 14 as shown in FIG. After being received by the wall, the clamp arm 5 is switched to the advanced position Y.

Then, as shown in FIG. 4C, when the first roller 21 is advanced along the swing surface A of the clamp arm 5, the first roller 21 is moved to the second roller. The force point portion 5b is swung upward around the fulcrum pin 13 while being received by the support groove 26 by the support groove 26, so that the action point portion 5c is clamped downward around the fulcrum pin 13 as above. Moved, mold D
Contact the upper surface of Subsequently, the first roller 21
Is advanced along the tightening surface B of the clamp arm 5, the first roller 21 swings the force point portion 5b strongly upward while being received by the support groove 26 by the second roller 22 of the same. The action point 5a is moved to the mold D
Press strongly.

In the clamp state, the clamp arm 5 is strongly held at the clamp position Z by the elastic force of the clamp state holding spring 45. Therefore,
Even if the pressure in the clamp working chamber 44 has disappeared due to leakage of compressed air from the supply pipe or the like, a sufficient clamp holding force can be secured by the action of the spring 45.

To release the clamped state shown in FIG. 4C, compressed air is discharged from the clamp working chamber 44 and compressed air is supplied to the unclamping working chamber 46.
The piston 40 and the piston rod 50 are moved rearward (to the right in the figure). Then, the first roller 2
1 retreats to the right to release the pushing force to the force point portion 5b, and then, as shown in FIG. . Subsequently, the retreating operation part 60 is engaged with the operated part 59 to switch the clamp arm 5 to the retreating position X in FIG. 4A.

The above embodiment has the following advantages.
Since the first roller 21 and the second roller 22 are arranged side by side in the left-right direction of the transmission shaft 20, even if the first roller 21 is made to have a large diameter in order to reduce the surface pressure at the time of clamping, these two types of rollers are used. The rollers 21 and 22 do not interfere in the vertical direction. Therefore, the height of the housing 3 accommodating the first roller 21 can be small, and the clamp device 2 can be made small and lightweight.

The width of the first rollers 21 can be set to a value obtained by subtracting the width of the connecting ring 24 from the width of the clamp arm 5.
Compared with the roller insertion groove 117 which is restricted by the groove width as shown in FIG. 6, a larger width dimension can be secured. Also from this point, the first roller 21 can be used smoothly over a long period of time with a small surface pressure.

Further, the first roller 21 and the second roller 22
Are supported by one transmission shaft 20, so that even if the clamp arm 5 is configured to be movable in the front-rear direction along the guide groove 14, the shaft centers of the two rollers 21 and 22 are always fixed to each other. Can be kept coaxial. For this reason, breakage due to misalignment of the shaft center in the above-described conventional example does not occur.

FIG. 5 shows a modification of the above-mentioned clamping device, and is a partial view corresponding to FIG. In this modification, the clamp device of the above embodiment is modified as follows.

The guide groove 14 is inclined backward and upward at a predetermined angle θ. The inclination angle θ is preferably set in a range from about 3 degrees to 10 degrees, but in this modification, it is set to about 5 degrees. By tilting the guide groove 14 in this manner, the following advantages can be obtained.

Since the clamp arm 5 can be clamped and unclamped in an oblique direction with respect to the clamped surface of the mold D, the arm 5 can be switched smoothly and reliably. More specifically, when the mold D is used for a long period of time, the surface to be clamped is plastically deformed in a concave shape at a portion pressed by the action point portion 5c, and an outer region of the pressed portion is formed. May be swollen due to burrs, rust, etc. caused by collision of other objects. However, the action point portion 5c of the arm 5 is moved forward and backward from the upper side diagonally, so that it is prevented from interfering with the above-mentioned bulging portion and is moved smoothly.

When the clamp arm 5 is switched from the advanced state Y shown in the solid line to the retracted state X shown in the two-dot chain line, the clamp arm 5 is raised by the retreat height V by the above-mentioned guide groove 14 rising upward. it can. Therefore, when the unclamping height U is set to a predetermined value, the size of the release height W can be reduced by the size of the retreat height V.

Therefore, the release swing angle of the clamp arm 5 can be reduced, and the release stroke of the piston 40 (not shown here, see FIG. 1 or 4) can be reduced. As a result, it is possible to reduce the length of the housing 3 in the front-rear direction and make the clamp device more compact. In addition, since the guide groove 14 is inclined upward rearward, the horizontal component acting on the front wall of the groove 14 from the fulcrum pin 13 during clamping can be small. For this reason, the housing 3 can be made small by reducing the thickness of the front wall of the guide groove 14.

The above embodiments and modifications can be further modified as follows. Instead of providing the first rollers 21 on both sides of the coupling ring 24 provided at the center of the transmission shaft 20, only one wide first roller is provided at the center of the transmission shaft 20. Connecting rings may be mounted on both sides. The needle roller bearing 25 can be replaced by a sliding bearing. Further, the sliding bearings 15 and 23 can be replaced by needle roller bearings. The sliding bearing may be made of a single material such as phosphor bronze or white metal.・
It is preferable to make it free.

The housing 3 includes a plurality of blocks 7.
Instead of the configuration of 8, 9, and 10, any two, three, or all of the plurality of blocks can be integrally formed. The guide groove 14 may be omitted from the housing 3. In this case, the clamp arm 5 is not moved in the front-rear direction, but is only swung in the vertical direction.

The pneumatic cylinder 6 as the driving means may be one in which the spring 45 for holding the clamped state is omitted, and may be constituted by a single-acting spring return type instead of the double-acting type.
Further, the driving means may use another type of compressed gas instead of the pneumatic cylinder, or may use a hydraulic cylinder or the like instead of these gas pressure cylinders. In the case where compressed air is used as the pressure fluid, the cost of the supply / discharge device and piping for the pressure fluid can be significantly reduced, and the atmosphere can be prevented from being contaminated by a liquid such as oil. Further, the driving means may be a mechanism which is advanced and retracted by engagement of a male screw and a female screw.

[0046]

The present invention has the following effects because it is constructed and operates as described above. (Invention of claim 1) Since the first roller and the second roller are juxtaposed in the left-right direction of the transmission shaft, even if the first roller is made to have a large diameter, these two types of rollers may interfere in the vertical direction. There is no. Therefore, the height of the housing accommodating the first roller can be small, and the clamp device can be made small and lightweight.

(Invention of claim 2) Since the first roller and the second roller are supported by one transmission shaft, even if the clamp arm is configured to be movable in the front-back direction along the guide groove, The axes of the two rollers can be kept coaxial at all times. For this reason, breakage due to misalignment of the shaft center in the above-described conventional example does not occur.

(Invention of claim 3) Since the guide groove is formed to rise rearward, it is possible to prevent the point of action of the clamp arm from interfering with the surface to be clamped, and to perform smooth clamping and unclamping movement. Further, since the clamp arm can be moved up and down by the inclination of the guide groove, the release height is set to a small value correspondingly, and the advance / retreat stroke of the output section of the drive means can be reduced. As a result, the length of the housing in the front-rear direction can be reduced to make the clamp device smaller and lighter.

(Invention of claim 4) Since the housing is constituted by a plurality of blocks, the machining allowance at the time of machining can be largely omitted as compared with an integrated type. Therefore, the material cost of the housing can be saved, and the manufacturing cost of the clamp device can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view of a clamp device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

4A and 4B are explanatory views of the operation of the clamp device, wherein FIG. 4A shows a retracted state, FIG. 4B shows an advanced state,
FIG. 4C shows a clamped state.

FIG. 5 shows a modification of the clamping device,
FIG.

FIG. 6 is a vertical sectional side view of a conventional clamping device.

[Explanation of symbols]

3 ... housing, 5 ... clamp arm, 5a ... fulcrum,
5b: power point portion, 6: driving means (pneumatic cylinder), 6a: output portion, 7: left block, 8: right block, 9: upper block, 10: lower block, 14: guide groove, 20: transmission shaft, 21: first roller, 22: second roller, θ: predetermined angle.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B21D 37/14 B23Q 3/06 302

Claims (4)

(57) [Claims] 1. A clamp arm (5) supported by a housing (3) extending in the front-rear direction so as to be vertically swingable, and a driving means.
A transmission shaft (20) which is moved in the front-rear direction by an output portion (6a) of (6), and a power point portion ( 5b)
And a second roller supported by the transmission shaft (20) near the left and right ends thereof and guided in the front-rear direction by the housing (3).
(22) A clamping device comprising: (22). 2. A clamping device according to claim 1, wherein said guide groove extends in a front-rear direction at a front part of said housing.
(14) A clamping device, wherein a fulcrum (5a) of the clamp arm (5) is supported in the guide groove (14) so as to be movable in the front-rear direction. 3. The clamping device according to claim 2, wherein the guide groove (14) is inclined backward and upward at a predetermined angle (θ). 4. The clamp device according to claim 1, wherein said housing (3) comprises left and right blocks (7) and (8) provided on both left and right sides of said clamp arm (5). Upper and lower blocks (9) (1) connecting left and right blocks (7) and (8)
(0).