JP3030776U - Hydraulic clamp device with lock function - Google Patents

Abstract

(57) [Summary] [Purpose] To prevent the risk of the mold falling or slipping when the hydraulic clamping force decreases. A hydraulic clamp device (1) has a clamp arm (4).
After the mold W is clamped at the action point portion 4b, the lock bolt 8 provided on the force point side of the clamp arm 4 is tightened to restrain and support the force point portion 4a side. When it is lowered, the clamping force of the mold W is secured by the clamping force by tightening the lock bolt 8.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a hydraulic clamp device used for fixing a mold to a mounting plate of a molding machine for plastic products.

[0002]

[Prior art and its problems]

 In the hydraulic clamp device that clamps the mold by hydraulic pressure, if the hydraulic pressure of the hydraulic cylinder drops due to damage to the hydraulic pipe, there is a risk that the mold will slip or drop. Especially on holidays, people will be out of the field for a long time, which may delay response and is dangerous.

Therefore, in addition to the hydraulic clamp, a spring or a disc spring is used, and when the hydraulic pressure is reduced, the clamping force is secured by the elastic force of the spring or the disc spring, so that the double-acting that holds the weight of the mold is performed. There is a method proposal. However, in the case of this double-acting method, it is difficult to support a heavy die of several tons only by elastic force, and according to the experiment, the clamping force when the hydraulic pressure is reduced is about 90% lower than that in the normal state. However, it is difficult to hold the mold with this clamping force.

Further, in Japanese Patent Publication No. 62-36818, a lock metal fitting 23 is provided on the side surface of the force point portion 8 of the clamp arm 6, and the lock metal fitting 23 is swung downward in a clamped state so that the front end thereof is rocked. By contacting the clamp arm 6 with the receiving surface 26 of the hydraulic cylinder to prevent the mold from dropping and shifting.

However, in the case of this method, since the lock fitting 23 functions as a wedge on the receiving surface 26 of the hydraulic cylinder, when unlocking the lock fitting 23, the release from the wedge state is smoothly performed. It may not be possible, and therefore the transition to the unlocked state may not be performed smoothly.

Further, in Japanese Utility Model Laid-Open No. 4-17029, when the pressing metal fitting 22 rotates in the ank ramp direction due to a decrease in hydraulic pressure, it is applied to the inner hole 13 of the main body 1 to prevent it from rotating to some extent. Although a method is disclosed, in the case of this method, if the pressing metal fitting 22 and the clamped product are separated from each other, there is a risk that the clamped product may drop if the weight of the clamped product is large. In addition, there is an example in which a pedestal is provided in the falling direction so that if a mold or tool falls due to a drop in hydraulic pressure, it will be caught below. However, if large tools or fittings fall, damage to the mold and tools is unavoidable.

[0007]

[Means for Solving the Problems]

 As described above, in the hydraulic clamp device, various safety mechanisms have been proposed for holding the mold and the tool when the hydraulic pressure is lowered, but in any case, especially in the case of a large mold or tool, However, it cannot be surely prevented from falling or slipping. Therefore, the purpose of the present invention is to provide a hydraulic clamp device having a safety function (lock function) that can securely hold the mold without losing the clamping force when the hydraulic pressure decreases. The configuration is as follows. is there.

In a hydraulic clamp device including a hydraulic cylinder, a clamp arm, and a clamp arm pedestal, a lock bolt is attached to a position farther from a force point portion as viewed from a support shaft of the clamp arm, and the hydraulic clamp device is mounted on the clamp arm. After the mold is clamped at the point of action, the lock bolt is tightened to restrain and support the force point side of the clamp arm, which maintains the clamping force and reduces the hydraulic pressure for some reason. The hydraulic clamp device with a lock function that prevents the mold from slipping or falling in case of damage.

[0009]

[Action]

 When clamping the mold, hydraulic pressure is applied to the hydraulic cylinder, and the piston in the hydraulic cylinder pushes up the force point of the clamp arm to press and fix the mold to the mounting board at the point of action of the clamp arm. This is the basic operation of.

When clamped by the above operation, the clamp arm is elastically deformed in a bow shape with the support shaft in the middle by the clamping force by hydraulic pressure, and the lock bolt is tightened until the elastically deformed state is maintained. The force points of the clamp arm are restrained and supported. Due to this action, even if the hydraulic pressure drops for some reason and the cylinder head goes down, the elastic deformation of the bow of the clamp arm does not change due to the movement of the lock bolt, and therefore the clamping force can be maintained. .

[0011]

[Embodiment of device]

 [Embodiment] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a hydraulic clamp device body, which is fitted in an inverted T-shaped groove 3 provided in a mounting plate 2 so as to be able to move forward and backward, and a mold W is mounted on the mounting plate 2. It is fixed by pressing.

Reference numeral 4 denotes a clamp arm rotatably supported by a support hole 5 a formed in the clamp arm pedestal 5 and a support shaft 6, and 4 a is a force point portion and 4 b is an action point portion. . The ratio of the distance between the power point portion 4a and the action point portion 4b is 1.3: 1. A screw hole 7 is formed on the right side of the force point portion 4a of the clamp arm 4 and at a distance (position) farther than the distance from the support shaft 6 to the action point portion 4b. The lock bolt 8 is screwed in toward the cylinder head 13 side. The ratio of the distance between the screw hole 7 with the support shaft 6 in the middle and the action point portion 4b is 1.8: 1.

After the lock bolt 8 is clamped by hydraulic pressure, it is tightened with a torque wrench to restrain and support the force point side of the clamp arm 4, thereby obtaining a clamp force by a mechanical method. . Reference numeral 9 denotes a hydraulic cylinder, which can drive the piston 10 by supplying the hydraulic pressure generated by a hydraulic pressure generating device (not shown) in the piston drive oil chamber 11 from the hydraulic pipe connection port 12. .

A cylinder head 13 is fixed to the upper surface of the hydraulic cylinder 9 as a cover. When pressure oil is supplied to the piston drive oil chamber 11, the piston 10 rises, and the piston upper surface 10a pushes up the force point portion 4a of the clamp arm 4 by this, and the working point portion 4b attaches the mold W to the mounting board. It works as if it were pressed against 2.

The operation of the above embodiment will be described below. FIG. 2 is a view showing a state in which the hydraulic clamp device body 1 with a lock function of the present invention clamps the mold W by hydraulic pressure. First, when pressure oil is applied from the hydraulic pipe connection port 12 into the piston drive chamber 11, the piston upper surface 10a pushes up the force point portion 4a of the clamp arm 4, and the action point portion 4b of the clamp arm 4 described above is leveraged by the lever principle. Then, the mold W is pressed against the mounting plate 2 and fixed.

At this time, when the clamping force of the action point portion 4b is 10t, the lever ratio of the clamp arm 4 of the present invention is 1: 1.3, so that the piston 10 is about 7.7t. It means that the force point portion 4a of the clamp arm 4 is pushed up by the force of.

In FIG. 2, the point of action 4b acts downward with a force of 10t, and the point of action 4a acts upward with a force of 7.7t. Further, as a result of the support shaft 6 being pushed down by the reaction force of both, the clamp arm 4 is elastically deformed in a bow shape and a large clamp force is obtained.

3 and 4 show a state in which the clamp arm 4 is elastically deformed in a bow shape with some emphasis. Further, when a mechanical clamping force is required, as shown in FIG. 3, the lock bolt 8 is rotated in the tightening direction with a torque wrench, and the tip 8a of the lock bolt 8 is brought into contact with the cylinder head upper surface 13a. Then, the lock bolt 8 is rotated until a more appropriate tightening torque is obtained.

As a result, the lock bolt 8 serves as a restraining support that functions as a support rod between the clamp arm 4 and the cylinder head upper surface 13a, and thus the clamp arm 4 is in a mechanically clamped state. As a result, even if the piston 10 in the hydraulic cylinder 9 descends due to a decrease in hydraulic pressure and the lock bolt 8 alone restrains and supports the elastic deformation of the clamp arm 4 in a bow shape. As a result, the clamping force required to hold the mold W is maintained.

At this time, the load applied to the lock bolt 8 is a lever ratio of 1: 1.8 because the position of the lock bolt 8 is farther from the support shaft 6 than the force point portion 4a. When the clamping force at the point of action 4b is 10t, it becomes 5.5t. Therefore, it can be seen that the load of the hydraulic cylinder 9 is lower than 7.7 t.

FIG. 5 shows the hydraulic clamping force and the clamping force of the lock bolt 8 in the hydraulic clamping device of the present invention that generates a clamping force of approximately 120,000 N (approximately 12.2 t) when a hydraulic pressure of 180 kgf / cm ² is applied. It shows the measured value. In FIG. 5, the set pressure of the hydraulic pump is shown on the X axis and the clamping force is shown on the Y axis. As a method of measuring the clamping force, first, the hydraulic pressure was applied to increase the hydraulic pressure to a predetermined level to put it in a clamped state, and the clamping force at that time was measured while changing the set pressure of the hydraulic pump. The change is shown by a broken line.

Next, after tightening the lock bolt 8 until a torque of 20 kgf · cm was obtained, the hydraulic pressure was released to clamp only the lock bolt 8 and the clamping force at that time was measured. The clamping force of the lock bolt 8 at this time is shown by a solid line. As can be seen from FIG. 5, the clamp force when the hydraulic pressure is 180 kgf / cm ² is 12.2 t, but the clamp force of only the lock bolt 8 is 11.2 t, and the clamp force of each measurement value is about 9%. Only the decrease of

In addition, the measurement was performed while changing the tightening torque to 10 kgf · cm and 15 kgf · cm, and the decrease in the clamping force was about 9% in both cases. The lock bolt 8 used in this hydraulic clamp device has the following specifications. Since the clamping force at the point of action is 12.2t, the load applied to the lock bolt 8 is 6.7t due to the lever ratio of 1: 1.8. If the nominal M20 strength classification 12.9 (using SCM435) is used as a bolt to support this load, the guaranteed tensile load is 30.5t, which is a safety factor 4.5 times that of 6.7t.

As described above, according to the lock mechanism of the present invention, in the case of the drawing, the mold is displaced or dropped even if the hydraulic pressure is lowered by the clamping force of only the lock bolt. It is possible to securely hold it without doing so. According to the present invention, the clamp arm is provided with the lock bolt at a position farther from the support shaft than the force point portion, so that the conventional clamp force of 90% is reduced to about 9% with a simple structure. Can be done.

In the case of the embodiment, the hydraulic clamp device main body 1 is a split type of the clamp arm pedestal 5 and the hydraulic cylinder 9, but the effect of the present invention is the same even if it is an integrated clamp device. can get. Further, it goes without saying that the present invention can be applied not only to a hydraulic clamp device that uses an inverted T-shaped groove of a mounting board but also to a clamp device that uses a hydraulic cylinder in general.

[0026]

[Effect of device]

 The present invention has the following effects due to the above-described configurations and operations. 1. Normally, it can be used as a hydraulic clamp, and when it becomes necessary to mechanically fix the clamp arm, tightening the lock bolt does not reduce the clamping force. The mold will not drop or slip due to the clamping force generated by. 2. The lock mechanism is inexpensive because the screw holes are machined in the clamp arm and the lock bolts are simply attached here. 3. Since a screw hole is formed in the clamp arm and the lock bolt is simply attached thereto, an inexpensive hydraulic clamp device can be obtained without significantly changing the shape of the conventional hydraulic clamp device.

[Brief description of drawings]

FIG. 1 is a side view of a hydraulic clamp device according to the present invention.

FIG. 2 is a side view showing a state where a hydraulic clamp device clamps a mold.

FIG. 3 is a side view showing a state in which a clamp arm of the hydraulic clamp device is elastically deformed and a state in which a lock bolt is tightened.

FIG. 4 is a plan view of the hydraulic clamp device in a clamped state.

FIG. 5 is an explanatory diagram of actual measured values of clamping force.

[Explanation of symbols]

 1 Hydraulic Clamping Device Main Body 2 Mounting Board 4 Clamp Arm 4a Force Point 4b Action Point 8 Lock Bolt 9 Hydraulic Cylinder 10a Piston Top 13a Cylinder Head Top W Mold

Claims (1)

[Scope of utility model registration request] 1. A hydraulic clamp device comprising a hydraulic cylinder, a clamp arm, and a clamp arm pedestal, wherein a lock bolt is attached at a position farther from a force point portion when viewed from a support shaft of the clamp arm, and the hydraulic clamp device is clamped. After the mold is clamped at the action point of the arm, the lock bolt is tightened to restrain and support the force point side of the clamp arm, which maintains the clamping force and causes the hydraulic pressure to drop for some reason. Hydraulic clamp device with a lock function that prevents the mold from slipping or falling when