JPH0144415B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive safety device for a transfer clamp unit used in a transfer press.

Conventionally, in transfer presses, a lever with a cam follower is pivoted to the front of the machine and corresponds to a plate cam provided on the slide, and a vertical rod connected to the other end of the lever reciprocates through a rack-and-pinion mechanism. A structure in which the clamp unit is driven by the clamp unit is often used. In this structure, there are various types of clamp units that have a safety device installed in the middle of the vertical rod that activates due to overload to prevent damage to the clamp unit. Safety that does not cause unreasonableness,
There was much room for improvement in ease of recovery after operation.

An object of the present invention is to make these improvements and provide a drive safety device for a transfer clamp unit that is excellent in responsiveness, safety, and ease of restoration. Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a plate cam 3 is fixed to a slide 2 provided on a transfer press 1 so as to be movable up and down. A lever 5 having at one end a cam follower 4 facing the plate cam 3 is pivotally attached to the body of the press 1. A vertical rod 6 is connected to the other end of the lever 5. The lower end of the vertical rod 6 is connected to a rack 8 provided on the drive unit 7 so that it can be raised freely. One end of the lower end of the rack 8 is connected to a piston rod of an air cylinder 9 pivotally mounted to the fuselage, and is biased downward. A hydraulic cylinder device 10 is installed in the middle of the vertical rod 6. A proximity switch 14 is fixed to the cylinder side of the hydraulic cylinder device 10, and a plate 15 is fixed to the piston rod side. Proximity switch 1
4 and plate 15 are provided to face each other, and detect when oil is drained from the hydraulic cylinder device 10 and transmit a signal to switch electromagnetic valves 19 and 31, which will be described later. The upper vertical rod 6 is a hydraulic cylinder device 10
The lower vertical rods 6 are respectively fixed to the piston rods of the cylinders. A clamp unit 11 is fixed between the columns 1a before and after the press 1. The drive shaft 12 of the clamp unit 11 is given horizontal movement and reciprocating rotation by the vertical movement of the rack 8 of the drive unit 7 through a rack and pinion mechanism and a planetary mechanism, and the feed bars 13 and 13 are given clamp/unclamp movements (mutual clamp/unclamp movements). (approaching and separating) and lift-down movements. The above-mentioned mechanisms of the plate cam 3 to the clamp unit 11 are provided in each set on the left and right columns 1a of the press 1, and are interlocked with each other.

In FIG. 2, the left and right columns 1a of the press 1
Two sets of hydraulic cylinder devices 10, 1 provided in the section
0 and air cylinders 9, 9, and a circuit for supplying oil and air thereto. A pressure oil supply device that supplies pressure oil to the cylinder chamber on the side that pushes up the piston of the hydraulic cylinder device 10 is provided. The pressure oil supply device includes a booster pump 16 that pumps up oil from a tank when compressed air is supplied, applies pressure to it, and sends it out, and a booster pump 16 that pumps compressed air from a compressed air source 17 to a constant pressure with a pressure regulating valve 18. It has a solenoid valve 19 for supplying and discharging water to and from the air. A hydraulic circuit connecting the hydraulic cylinder device 10 and the booster pump 16 is provided with relief valves 20, 20 corresponding to the hydraulic cylinder devices 10, 10.
The relief valve 20 is of a balanced type and has a structure that discharges pressure oil when the balance between the pressure oil in the hydraulic circuit and the constant pressure air is lost. relief valve 2
An air cylinder is provided in the lower part of the frame of 0, and the piston 21 that the piston 21 fits in is forced upward by constant pressure air supplied through the solenoid valve 19 and pressure regulating valve 22 and by a return spring 23. is energized by The cylinder inner diameter of the portion housing the return spring 23 is slightly larger than the outer diameter of the piston 21, so that when the piston 21 comes to this portion, compressed air escapes upward.
The upper cylinder of the piston 21 has a vent and is open to the atmosphere. A cylindrical check valve 24 has a shelf plate portion 24a that fits the piston rod of the piston 21 on the upper part of the frame of the relief valve 20.
is accommodated. A valve seat 25 is provided on the frame corresponding to the upper outer periphery of the check valve 24. The lower outer periphery of the check valve 24 is guided by a frame, and a passage for pressure oil is provided in the shelf section 24a. A step portion 21a is provided at the upper end of the piston rod of the piston 21 and is engaged with a shelf portion 24a. A balance collar 26 is provided which fits the partition of the frame of the relief valve 20 and the piston rod of the piston 21 in an oil-tight manner.

A return spring 27 for the check valve 24 is provided between the shelf plate 24a of the check valve 24 and the piston 21 via the balance collar 26. The housing chamber of the check valve 24 is connected to an oil tank 28. A cam 29 is provided on the lower piston rod of the piston 21 and corresponds to a limit switch 30 fixed to the frame of the relief valve 20.
The limit switch 30 is switched by a cam 29 and sends a signal to switch the solenoid valve 19 which controls the operation of the booster pump 16.

Air cylinders 9, 9 that urge the vertical rod 6 downward are connected to solenoid valves 31, 31 from a compressed air source 17.
Compressed air is supplied to the upper cylinder chamber of the piston through the piston. The electromagnetic valves 31, 31 supply air in response to an electric signal while the press 1 is in operation, and when an overload is detected by the proximity switch 14, they are switched in response to the signal and the compressed air in the air cylinder 9 is exhausted.

Next, we will discuss the effect. In FIGS. 1 and 2, compressed air is supplied from a compressed air source 17 before the press 1 is operated. Turn on the reset button (located on the operation panel) and send a signal to solenoid valves 19 and 31. Air is supplied from the solenoid valve 19 and pressure oil is sent from the booster pump 16 to the hydraulic cylinder device 10. At the same time, compressed air is supplied to the relief valve 20 via the pressure regulating valve 22, and the piston 21 is pushed up. The cam 29 of the piston 21 has moved upward away from the limit switch 30. When the oil pressure gradually increases and the force of the pressure oil pushing down the piston 21 via the upper piston rod and balance collar 26 is balanced with the force of the compressed air pushing up the piston 21, the cam 29 activates the limit switch 30 and outputs a signal. This signal causes the solenoid valve 19 to switch and the booster pump 16 to stop. At this time, pressure oil at a constant pressure is supplied to the hydraulic cylinder device 10. Compressed air is also supplied to the air cylinder 9 via the solenoid valve 31, and the press 1 is ready for operation. Next, while the press 1 is in operation, the vertical rod 6 is pulled upward by the cam 3 provided on the slide 2 via the lever 5, and the feed bar 13 is activated via the rack 8 and the drive shaft 12 to perform an unclamping operation. If the operation is obstructed by obstacles when doing so, an overload will be applied to the hydraulic cylinder device 10. Since the piston of the hydraulic cylinder device 10 tends to move downward with respect to the cylinder, the pressure of the supplied pressure oil is increased. When the relief valve 20 becomes unbalanced and the piston 21 is pushed down, and the piston 21 reaches the large diameter part of the lower cylinder chamber and a gap is created on the outer periphery, the air in the lower cylinder chamber of the piston 21 escapes to the outside air through the vent, and the piston 21 is pushed down. 21 is pushed down, the stepped portion 21a of the piston 21 also pushes down the check valve 24, allowing pressurized oil to escape into the oil tank 28. When the pressure oil in the hydraulic cylinder device 10 escapes and the piston descends, the proximity switch 14 releases the plate 1.
5 sends a signal away. In response to this signal, the electromagnetic valves 19 and 31 are switched to exhaust mode and the air is rapidly exhausted, the booster pump 16 becomes inoperable, and the air cylinder 9 is exhausted to remove the downward biasing force of the vertical rod 6. Therefore, the overload on the vertical rod 6 is eliminated and the biasing force is also removed, so that damage to various parts does not occur. To return, simply press the reset button again.

As is clear from the above description, according to the present invention, (1) overload is detected by a sensitive relief valve and pressure oil is discharged, so responsiveness is excellent. (2) The discharge of pressure oil is detected by a proximity switch, the booster pump is disabled, and the air cylinder is rapidly evacuated to remove the biasing force of the vertical rod, which relieves strain on each part, prevents damage, and provides safety. Improves sex.
(3) You can restore it immediately by pressing the reset button. The practical effects and advantages are extremely large.

[Brief explanation of drawings]

FIG. 1 is a partially sectional side view showing the drive mechanism of the clamp unit, and FIG. 2 is a partially sectional side view showing the structure of the embodiment. 1 is a transfer press, 1a is a column, 2 is a slide, 3 is a plate cam, 4 is a cam follower, 5 is a lever, 6 is a vertical rod, 7 is a drive unit, 8 is a rack, 9 is an air cylinder, 10 is a hydraulic cylinder device, 11 is a clamp unit, 12 is a drive shaft, 1
3 is a feed bar, 14 is a proximity switch, 15 is a plate, 16 is a booster pump, 17 is a compressed air source, 18 is a pressure regulating valve, 19 is a solenoid valve, 20 is a relief valve, 21 is a piston, 21a is a stepped portion, 22 is Pressure regulating valve, 23 is a spring, 24 is a check valve, 24a
25 is the valve seat, 26 is the balance collar,
27 is a spring, 28 is an oil tank, 29 is a cam, 30
is a limit switch, and 31 is a solenoid valve.

Claims (1)

[Claims] 1. A lever whose middle part is pivotally mounted to the body of the press, and whose upper end is connected to the other end of the lever, which is brought into contact with an upwardly rising and inclined plate cam provided on the slide of the press. , the vertical rod whose lower end is connected to the piston of an air cylinder fixed to the lower fuselage via the rack of the drive unit and is urged downward to clamp and unclamp the transfer, the vertical rod is moved up and down. A hydraulic cylinder device connected and provided in a separate intermediate portion, a balanced relief valve provided in a hydraulic circuit that supplies pressure oil in a direction in which a piston rod of the hydraulic cylinder device is retracted, and a cylinder and a piston rod of the hydraulic cylinder device. a detector provided between the hydraulic circuit and an air circuit for supplying pressurized air to the hydraulic circuit of the hydraulic cylinder device and the air cylinder for supplying pressurized air to the air cylinder; A drive safety device for a clamp unit of a transfer, comprising: a valve that operates from supply to exhaust pressure in response to a detection signal from a detector;