JPH0593813U - Clamp device - Google Patents

Abstract

(57) [Summary] [Purpose] Clamping is performed by fluid pressure.
Provide a structure that does not loosen due to the decrease in the fluid pressure. A clamp rod 20 having an engaging portion 25 at a front end portion thereof and a through hole 26 at a rear end portion thereof in a direction perpendicular to the longitudinal direction.
And a wedge shaft 21 formed by passing through the through hole of the clamp rod, the surface of the through hole facing the inner surface of the rear end side of the clamp rod being inclined to one side in the longitudinal direction,
The main body 35 supports the portions on both sides of the wedge shaft protruding from the through hole so as to be movable back and forth in the direction of the axis thereof, and the forward / backward drive cylinder device 22 connected to one end of the wedge shaft.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a clamp device which is used when a mold of an injection molding machine or a press machine is mounted on a substrate or the like, and in which the clamping action force does not disappear even when the fluid pressure applied in the clamping state decreases.

[0002]

[Prior Art]

 Conventional clamping devices of this type have considerably complicated structures, but they are not simple and small. One that is only simplified and miniaturized is shown in FIG. 3, for example. The clamp device 10 includes a cylinder 1, a piston 2, a piston rod 3, a return spring 4 and the like. When pressure oil is supplied into the cylinder 1, the piston rod 3 is pulled into the cylinder 1 against the return spring 4. As a result, a clamping action is exerted between the engagement portion 5 provided at the end of the piston rod 3 and the cylinder 1. When the hydraulic pressure is removed, the clamping force disappears and the return spring 4 restores the original unclamping state. In the figure, 6 is a mold, 7 is a U groove provided in the mold, 8 is a bolster (or slide), and 9 is a T groove provided in the bolster (or slide).

This type of clamping device is used not only in the positional relationship shown in FIG. 3 but also in the positional relationship shown in FIG. FIG. 4 shows a state where the upper die 12 is clamped to the slide 11 by the clamp device 10a and the lower die 14 is clamped to the bolster 13 by the clamp device 10b. The clamp device 10a is fixed to the slide, The mold 12 is provided with a T groove 15, and the mold 12 is moved in the direction of the T groove 15 when the mold is replaced. The clamp device 10b is manually attached / detached to / from a predetermined position during die replacement. The illustration of the hydraulic hose is omitted. In the figure, 16 and 17 are U grooves.

[0004]

This conventional compact clamping device that can be formed is designed to clamp directly with the output of a hydraulic cylinder. Therefore, when the hydraulic pressure is reduced, the clamping action is reduced. For example, when the upper die is used for fixing the upper die to the slide, the upper die is lowered by its own weight by the tightening margin of the clamp device. As a result, the positional relationship between the upper mold and the lower mold changes, and there is a problem that the mold will be damaged if the lower stroke is continued.

An object of the present invention is to provide a clamp device that performs a clamping operation by a fluid pressure, is simple and small, and does not loosen due to a decrease in the fluid pressure being supplied.

[0006]

[Means for Solving the Problems]

 The clamp device of this invention has a clamp rod having an engaging portion at the front end and a through hole at the rear end in a direction perpendicular to the longitudinal direction, and a through hole through the through hole of the clamp rod. The surface of the hole facing the inner surface on the rear end side of the clamp rod is formed so as to be inclined to one side in the longitudinal direction, and the parts on both sides of the wedge shaft protruding from the through hole can be moved back and forth in the direction of the axis. It comprises a supporting body and an advancing / retreating drive cylinder device connected to one end of the wedge shaft.

In this clamp device, the cylindrical member can be rotated so that the inner surface of the through hole on the rear end side of the clamp rod crosses the through hole on the rear end side of the clamp rod so as to match the inclined surface of the wedge shaft. It is preferable that a flat surface which is in contact with the inclined surface is formed in the peripheral surface of the cylindrical member by notching. Further, in this clamp device, it is preferable to interpose a compression spring so as to press the clamp rod toward the tip side thereof.

[0008]

[Action]

 In this clamp device, a structure for driving a clamp rod backward for clamping is performed by a wedge action by axially moving a wedge shaft acting between a through hole and a fixed support portion. When the clamp rod is in the unclamped state where it has advanced from the clamped state, when the cylinder device moves the wedge shaft from one direction to the other axial direction, the inclined surface pushes the inner surface of the through hole on the rear end side of the clamp rod, causing a wedge action. When the cylinder rod moves in the opposite direction to the above, the wedge action is released and the clamp rod returns to the unclamped state by its own weight and other actions. In this unclamped state, the mold etc. are replaced.

In the configuration in which the columnar member having the flat surface cut out is provided, the columnar member rotates and adapts, so that the inclined surface of the wedge shaft is surely provided on the rear end side of the clamp rod of the through hole. Since it will be hard to wear due to contact, it is advantageous in that it does not cause any trouble due to wear. In other words, if no columnar member is provided, it may be possible to form the inner surface of the through hole into an inclined surface that matches the inclined surface of the wedge axis, but in reality, a slight machining error causes a line or point contact. Therefore, it is more common to form ridges and make line contact. In that case, since the ridges are easily worn, the limit position of the structure of the clamp rod is gradually changed to the front due to the wear, and the clamp is hindered.However, when the columnar member having the above-mentioned plane is provided, this problem occurs. Is solved.

The configuration in which the compression spring is interposed has a problem that the unclamped state does not occur because the clamp rod retracts due to the margin between the through hole and the wedge shaft due to its own weight depending on the usage state of the clamp device. The spring pushes up the clamp rod to solve this problem.

[0011]

【Example】

 An embodiment will be described with reference to FIGS. 1 and 2. In the figure, 20 is a clamp rod, 21 is a wedge shaft, and 22 is a cylinder device.

The clamp rod 20 has an enlarged engaging portion 25 that engages with the U groove end of the mold at the lower end in the figure, has a cylindrical shape in the middle, and a flat upper rear end. A through hole 26 is formed at a right angle through the flat surface. The through hole 26 is of a size into which the wedge portion 21a of the wedge shaft 21 described later is inserted, the width dimension corresponds to the width of the wedge portion 21a, and the vertical dimension is sufficiently larger than the maximum vertical dimension of the wedge portion 21a. large. The inner surface of the through hole 26 on the rear end side of the clamp rod (upper inner surface in the figure) is formed as a contact surface with which the inclined surface 38 of the wedge portion 21a abuts. The contact surface is formed by drilling a small cylindrical member 28 having a notch plane 27 in a part of the circumference in a direction along the flat surface of the flat portion of the clamp rod 20, that is, in a direction crossing the through hole 26. It is rotatably inserted into the circular hole 29 provided so that the notch plane 27 faces the inside of the through hole 26. A circular hole 30 is bored in the inner surface of the through hole 26 on the tip end side of the clamp rod (lower inner surface in the drawing), and a cap 31 is housed in the compressed coil spring 32 covered with a cap 31. It is made to project to the inner surface of 26.

As shown in FIG. 1, the wedge shaft 21 has a support portion with respect to a main body 35 having bearing-shaped support portions 33 and 34 located on both sides of the flat portion of the rear end portion of the clamp rod 20. It is a wedge-shaped member that is inserted through the circular holes 36 and 37 of 33 and 34 and the through hole 26 of the clamp rod 20 to support the clamp rod. The wedge shaft 21 is a columnar one that slidably fits over both of the circular holes 36 and 37, and forms a slanted surface 38 that descends from right to left in the figure. The wedge portion 21a is formed by cutting the both side surfaces to have a predetermined width corresponding to the width of the through hole 26. The inclined surface 38 is in surface contact with the notch plane 27 of the cylindrical member 28, and the opposite circumferential surface is in contact with the cap 31. In this state, both ends of the wedge shaft 21 are supported by the circular holes 36 and 37 of the supporting portions 33 and 34. The spring 32 has a function of causing the inner surface of the through hole 26 on the rear end side of the clamp rod, that is, the notch plane 27, to always contact the inclined surface 38.

The cylinder device 22 drives the wedge shaft 21 forward and backward in the direction of its central axis, and in FIG. 1, the piston rod portion 39 is integrally formed continuously with the right end of the wedge shaft 21 and the rod portion 39. It is composed of an annular piston 40 slidably fitted to the cylinder, and a cylinder 41 that houses the piston 40 and is fixed to the main body 35. The right end of the piston rod portion 39 has a retaining portion 42 for the piston 40. When the cylinder device 22 supplies pressure oil to one chamber 43 with respect to the piston 40 and discharges it from the other chamber 44, the cross-sectional area of the piston rod portion 39 is the effective pressure receiving area at this time, and the wedge pressure is applied by the hydraulic pressure acting on it. Drive shaft 21 to the left as shown. When pressure oil is supplied to the chamber 44 and discharged from the chamber 43, the cross-sectional area of the annular piston 40 is the effective pressure receiving area, and the wedge shaft 21 is driven to the right in the figure by the hydraulic pressure acting on this. The effective pressure receiving area is 1.5 times for the right row and 1.5 times for the left row, and the work force in the direction of removing the wedge is increased.

In the figure, reference numerals 60, 61 and 62 denote close switches for detecting the end position of the wedge shaft 21, which detect an empty clamp, a clamp and an unclamp, respectively.

In the case where the clamping device is used to attach the die 51 to the slide 50 of the press machine, for example, the tip of the clamp rod 20 is directed downward as shown in the figure, and the main body 35 is fixed to the slide 50 with the bolt 52. To use. In the figure, 53 and 54 are U grooves provided on the slide 50 and the mold 51. The state of the clamp rod 20 shown by the solid line in the figure is the clamped state. In this clamped state, the mold engaging portion 25 at the tip of the clamp rod 20 is engaged with the lower end of the U groove 54 of the mold 51, and the wedge shaft 21 is moved by the cylinder device 22 to the right as shown in FIG. The clamp rod 20 is driven upward and the clamp rod 20 is pulled upward by the wedge action of the wedge portion 21a. From this clamped state, when the cylinder device 22 is operated to move the wedge shaft 21 to the right in FIG. 1, the wedge action is released, and the clamp rod 20 is lowered by that amount and becomes the unclamped state. In this state, the mold 51 is replaced. When clamping the exchanged mold, the cylinder device 22 moves the wedge shaft 21 to the left in FIG.

Since this clamp device has a configuration in which the clamp cylinder device 22 is provided on the side of the clamp rod 20, the length H1 of the clamp rod advance / retreat drive unit in the clamp rod advance / retreat direction is extremely small. Short. Therefore, it is effective when the height H of the mounting portion is small as shown in FIG. Also, since the wedge action is used, the clamped state is maintained without being affected by the decrease in the clamping hydraulic pressure. Therefore, in the clamped state, even if the hydraulic pressure is lowered, the clamping action is maintained as it is, so that the upper die 51 is not displaced.

Although the wedge shaft 21 and the piston rod 39 of the cylinder device 22 are integrally formed in the above embodiment, they may be separately formed and connected to each other if there is a spare space.

[0019]

[Effect of the device]

 Since the clamp device of the present invention utilizes the wedge action, it is possible to obtain the effect that the clamp action is not reduced even if the clamping hydraulic pressure is reduced. Therefore, it is possible to obtain the effect of preventing the die from dropping and breaking.

In addition, according to the configuration of the second aspect, it is possible to obtain an effect that it is difficult for trouble to occur due to wear of the inclined surface of the wedge and the inner surface of the through hole of the clamp rod that abuts against the inclined surface.

Further, according to the configuration of the third aspect, there is an effect that the tip side of the clamp rod can be used with the tip side facing upward.

[Brief description of drawings]

FIG. 1 is a partial vertical front view showing an embodiment of the present invention.

FIG. 2 is a side view of the embodiment.

FIG. 3 is a partial vertical sectional front view showing an example of a conventional clamp device.

FIG. 4 is a schematic side view showing an example of a usage state of a conventional clamp device.

[Explanation of symbols]

 20 Clamp Rod 21 Wedge Shaft 21a Wedge Part 22 Cylinder Device 25 Engagement Part 26 Through Hole 27 Notched Plane 28 Small Cylindrical Member 29 Circular Hole 32 Compressed Coil Spring 33 Supporting Part 34 Supporting Part 35 Main Body 36 Circular Hole 37 Circular Hole 38 Inclined surface

Claims (3)

[Scope of utility model registration request] 1. A clamp rod having an engaging portion at a front end thereof and a through hole at a rear end thereof in a direction perpendicular to a longitudinal direction, and a clamp rod of the through hole passing through the through hole of the clamp rod. A main body that supports a wedge shaft whose surface facing the inner surface on the rear end side is inclined to one side in the longitudinal direction, and parts on both sides of the wedge shaft protruding from the through hole so that the wedge shaft can advance and retreat in the axial direction. And a forward / backward drive cylinder device connected to one end of the wedge shaft. 2. The clamp device according to claim 1, wherein the through hole is traversed on the rear end side of the clamp rod so that the inner surface of the through hole on the rear end side of the clamp rod matches the inclined surface of the wedge shaft. A clamping device, wherein a cylindrical member is rotatably provided on the cylindrical member, and a flat surface that abuts the inclined surface is cut out on the peripheral surface of the cylindrical member. 3. The clamp device according to claim 1 or 2, wherein a compression spring is interposed so as to press the clamp rod toward the tip side thereof.