JPS60234800A - Overload protector - Google Patents

Abstract

PURPOSE:To actuate simultaneously a relief valve and switch with simple construction and to eliminate the influence on the liquid pressure of a press machine in an overload protector for the press machine, etc. by incorporating integrally the relief valve, sensor and switch into said protector. CONSTITUTION:A hydraulic cylinder chamber 4 of a press machine, etc. is connected to a discharge port 7 of an overload protector 6 and an oil tank 10 is connected to the discharge port 12 of the protector 6. The pressure oil is discharged to the tank 10 by the effect of the 1st relief valve 19 of the protector 6 when the pressure in the cylinder chamber 4 increases. The pressure increase acts on the 2nd relief valve 22 and the fluid is discharged when the pressure exceeds the prescribed pressure. The fluid flows into a sensor chamber 24 where the fluid pushes and moves the sensor 23 against the fluid pressure in a branch 25 to open the switch 26, thereby stopping the machine. The timing of the sensor 23 and the 2nd relief valve 22 is surely set by the above-mentioned device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an accidental load protection device for a machine operated by hydraulic pressure, such as a press machine.

Conventional overload protection devices for press machines include a relief valve, bypass path, and pressure switch notch in the circuit of the booster pump device that operates the machine, and when an overload occurs, the relief valve operates to prevent the circuit from overpressure. A device has been proposed that protects the machine and at the same time stops the machine by operating a pressure switch to prevent damage. Such overload protection devices have the disadvantage that each device must be prepared individually and assembled into a circuit, which is time consuming and costly. Furthermore,
The drawback was that the operating timing of the relief valve and pressure switch could not be easily adjusted.

The present invention solves the above-mentioned drawbacks of conventional overload protection devices constructed by assembling individual devices, and provides an overload protection device constructed as a single unit with a simple structure, and a relief valve and a relief valve. The object is to provide a device that allows switches to be activated almost simultaneously.

The invention has achieved this object by creating a device which can be connected to a pump, for example a booster pump, and which integrates a relief valve, a sensor and a switch.

The details of the present invention will be explained based on embodiments shown in the drawings.

In Figure 1, 51 and 1
A slide 3 spherically connected to the connecting rod 1 is slidably provided on a press plate 2 that is reciprocated downward and presses a workpiece, and further a hydraulic cylinder chamber 4 that applies pressure to the slide 3 is formed. . The hydraulic cylinder chamber 4 is connected to the discharge lower of the overload protection device 6 by a flow path 5 . The hydraulic cylinder chamber 4 can be connected to a liquid storage tank 10, for example an oil tank, by a flow path 9 with a pressure valve 8.

The oil tank 10 is connected to the outlet 12 of the overload protection device 6 by a flow path 11 .

The overload protection device 6 has a suction port 15 which is connected via a check valve 13 to a pump 14, for example a booster pump.

The inlet of the pump 14 is connected to the oil tank 10 via a check valve 16, and in the case of a booster pump, it is also connected to a driving fluid source 1.
Connected to 7. The suction port 15 of the overload protection device 6 is connected to the discharge lower by a flow path 18, and the flow path 18 is connected to the discharge port 12 via a first relief valve 19. In the first relief valve 19, the pressure of the flow path 18 acts directly on one side of the valve body, and the pressure of the flow path 18 acts on the other side through the throttle 20, and at the same time, the force of the spring 21 acts on the other side of the valve body. The first relief valve 19 discharges fluid from the flow path 18 to the oil tank 10 when the pressure in the oil tank 18 suddenly increases.

The flow path 18 is further connected to the second relief valve 2 via the throttle 20.
The outflow side of the second relief valve 22 is connected to the vicinity of one end of the sensor chamber 24 that slidingly guides the sensor 23, and the vicinity of the opposite end of the sensor chamber 24 is connected to the inflow side of the second relief valve 22. It is connected to the branch path 25 of the flow path 18 .

When the pressure in the hydraulic cylinder chamber 4 suddenly increases due to overload, pressure oil is released into the oil tank 10 by the action of the first relief valve 19.
On the other hand, the pressure increase acts on the second relief valve 22 through the throttle 20, and when the pressure is higher than a predetermined pressure, the fluid is discharged from the second relief valve 22. This discharged fluid, i.e.
The leakage fluid from the relief valve 22 flows into the sensor chamber 24 and pushes the switch 26, e.g. the sensor 23 which closes the proximity switch, against the fluid pressure in the branch 25, causing the switch 26 to open. The press machine is stopped by closing the switch 26.

In a normal state, the sensor 23 is only affected by the pressure of the branch passage 25, the force opposing the pressure of the branch passage 25 within the sensor chamber 24, and the force of the spring 27 acting on the sensor 23, and the pressure of the branch passage 25 is is set to be greater than the force of spring 27, so sensor 23 is pushed to the left in the figure and switch 2
Hold 6 open.

If the machine is operated without any hydraulic pressure, excessive force will be applied and there is a risk of damage. This danger can be avoided by the following method: When no hydraulic pressure is applied, no hydraulic pressure acts on the flow path 1B and the branch path 25, so the sensor 23 is pushed by the spring 27 and is located at the right end position in the figure.
Sensor 23 is bypassed in this position by closing switch 26 and stopping the machine.

An embodiment that implements the principle of the present invention shown in FIG. 1 will be described below.

In FIGS. 2 and 3, the casing 28 of the overload protection device 6 has an outlet 12 connected to a storage tank (not shown) and an outlet connected to an operating machine, such as a press machine. A lower portion and an inlet 15 connected to an outlet of a booster pump (not shown) are formed. Said casing 2
A slide cylinder device 29 that acts as the first relief valve 19, a relief valve device 30 that acts as the second relief valve 22, and a sensor device 31 are integrally inserted into the device 8. The slide cylinder device 29 and the relief valve device 30 form a balanced piston type relief valve.

The slide cylinder device 29 has a valve body part 32, and the valve body part 32 has a passage 3 communicating with the discharge port 12 of the casing 28.
3 and a fluid chamber 34 that communicates with the discharge lower.

The valve body 32 is fixed to or integrally formed with a hollow cylindrical sliding body 36, and the sliding body 36 is slidably inserted into a cylinder hole 37 of the casing 28. The hollow hole of the sliding body 36 opens into the fluid chamber 34 through a throttle hole 38 .

A spring 40 is installed between the sliding body 36 and a spring seat 39 of the casing 28 to press the sliding body 36 against the valve seat 35.

A relief valve device 30 is provided in the cylinder hole 37 of the slide cylinder device 29 so as to open and close a flow path 41 communicating with the sliding body 36 near the end on the opposite side from the valve body portion 32 . The relief valve device 30 includes a relief valve body 43 that opens and closes between the flow path 41 and the valve chamber 42, an adjustment piece 44 that is slidably provided on the casing 28, and a relief valve body 43 that opens and closes between the flow path 41 and the valve chamber 42, an adjustment piece 44 that is slidably provided on the casing 28, and a relief valve body 43 that opens and closes between the flow path 41 and the valve chamber 42. 44 and presses the relief valve body 43 against the valve seat 45 between the flow path /II and the valve chamber 42.

By adjusting the position of the adjusting piece 44 using an adjusting screw 47 screwed into the casing 28, the relief pressure is adjusted.

Connection f? communicating with the valve chamber 42 of the relief valve device 30? 8
A part of the fluid in the valve chamber 42 is guided to the sensor chamber 24 of the sensor device 1. A sensor 23 (formed in the shape of a piston and made of a magnetic material) is slidably housed in the sensor 24.

The sensor chamber 24 has a branch passage 25 connected to the inlet 15 on the opposite side of the connection passage 48 with the sensor 23 in between.
is opened, and the branch passage 25 is connected to the booster pump and introduces the pressure oil of the booster pump. A spring 27 is provided in the sensor chamber 24 between the casing 28 on the side facing the connection path 48 and the sensor 23, and the spring 27
presses the sensor 23 against the fluid pressure flowing through the branch 25.

A switch, for example, a proximity switch 26, is attached to the casing 28, and the sensor 23 is located in the operating area A shown by the dotted line in the figure of the proximity switch 26 (when the proximity switch 26 is in the position shown in the figure, the 7-point proximity switch 26 is closed). When the sensor 23 moves away from the operating area A, the proximity switch 26 opens. That is, the switch 26 is opened or closed according to the position of the sensor 23.

A pin portion 52 is formed on the sensor 23 of the sensor device 31 on the side facing the branch path 25 , and the pin portion 52 projects into a guide hole 53 of the casing 28 . The guide hole 53 communicates with the branch passage 25, and the fluid pressure of the booster pump acts on the pin portion 524.

The sensor chamber 24 is connected to the exhaust "112" by a flow path 54.
It has an opening 55 communicating with. The opening 55 opens when the sensor 23 is pushed 11 by the force of the spring 27, and opens when the sensor 23 is moved by the fluid pressure of the booster pump against the force 6j of the spring 27. , be closed tH11.

The operation of this device will be explained below.

11v, a liquid (for example, pressure oil) that operates a machine, such as a press machine, is sucked into the overload protection device 6 from the booster pump through the suction port 15, and is supplied to the machine via the discharge lower (U). Ru.

When the hydraulic pressure of the machine increases, that is, the hydraulic pressure of the fluid chamber 34, the fluid chamber 34 and the sliding body 36 are closed by the throttle hole 38 of the sliding body 36.
A pressure difference is generated between the valve body 32 and the hollow part, and the valve body 32 is pushed against the force of the spring 40 as shown in FIG. The liquid flows out into the liquid storage tank 10 through the discharge port 12 in a short time, reducing the fluid pressure inside the machine in a short time. At the same time, when the liquid pressure in the flow path 41 increases due to the movement of the sliding body 36 and exceeds the set value of the relief valve device 30, the relief valve 43 opens the valve PH45, and the liquid flows into the sensor chamber 27I via the connection path 48. , the sensor 23 is moved to the right in the figure and the switch 26 is opened to stop the operation of the machine.

Due to the action of the sliding body 36 and spring 40, the
Close the valve seat 35. Furthermore, the movement of sensor 23 J f&
When the opening 55 opens, a part of the fluid in the center chamber 24 leaks into the flow path 54, and the fluid pressure in the valve chamber 42 decreases, causing the sensor 2
3 is restored by the hydraulic pressure on the branch path 25 side.

If the machine is operated without any hydraulic pressure, excessive force will be applied and there is a risk of damage. In order to avoid this, the pin portion 52 acts. That is, when no hydraulic pressure is applied, no hydraulic pressure is applied to the branch passage 25 leading to the guide hole 53, so that the pin portion 52 of the sensor 23 and the spring 51 of the sensor 4j--23 are pressed as shown in FIG. is,
Sensor 23 is IP! The sensor +-23 is in the right position 1''lR) at this position to open the switch 26 and stop the machine.

u (j When hydraulic pressure is acting on the machine, the hydraulic pressure acts on the branch path 25 passing through the guide hole 53, pushing the pin part 52,
Therefore, by pushing the sensor 23 and moving it to the left in the figure, the sensor 23 closes the switch 26 and the machine can be operated.

According to the invention, the overload protection device can be formed as an integrated and compact device 7, and the slide cylinder device, i.e. the relief valve and the switch, can be operated at the same time, eliminating the need for adjustment. . Further, in the present invention, since the sensor is actuated by leakage liquid from the relief valve, the timing of the sensor and relief valve can be set reliably, and no extra liquid is required to affect the hydraulic pressure of the machine. It became possible to activate the sensor without any problems.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of the device according to the present invention, Fig. 2 is a sectional view of an embodiment of the device according to the present invention, and Fig. 2 is a diagram showing the valve body of the slide cylinder device in an open state. The corresponding figure, FIG. 4, is a partial view showing a state in which no pump operating pressure is applied. 6...Overload protection device 7...Discharge port 10...Liquid storage tank 12...1) 1 outlet 14...Pump]
5... Suction port 18... Channel 19... First relief valve 21...
Throttle 22...Second relief valve 23...Sensor
24...Sensor chamber 25...Branch path 26...Switch 27...Spring 28...Ge sink 29...Slide cylinder device Wf 30...Relief valve device 31...Sensor device 3
2... Valve body part 36... Sliding body 37... Cylinder hole 43... Relief valve body 42
... Valve chamber 46 ... Spring 52 ... Pin part 53 ... Guide hole procedure amendment form) August 3, 1980 Manabu Shiga, Commissioner of the Japan Patent Office 1, Indication of the case 1988 patent Application No. 88506 2, Name of the invention Overload protection device 3, Relationship with the amended case Patent applicant name Konan Denki Co., Ltd. 4 Agent address Kaji Kogyo, 2-32-4 Nishi-Shinbashi, Minato-ku, Tokyo building
105 Expenses (433) 4564 July 11, 1988 A column for a brief explanation of the drawings in the statement. 7. Contents of the amendment Changed “Figure 2” from line 1 of page 14 of the present specification to “Figure 3.”
The figure is corrected. −\

Claims (2)

[Claims] (1) In an overload protection device connected in the middle of a wave path connecting a pump and a machine, an inlet port connected to the outlet of the pump, a discharge port connected to the machine, and a discharge port connected to the liquid storage tank are used. A casing having an outlet is provided, and a flow path connecting the suction port and the discharge port is provided in the casing, and a first relief valve connected to the flow path connecting the suction port and the discharge port. and a first relief valve on one side of the valve body of the first relief valve.
The inlet side flow path of the relief valve is connected and opened, and the inlet side flow path of the first relief valve is connected and opened on the other side through a throttle, and a spring force is applied to the first relief valve. a second relief valve connected to the inlet flow path of the relief valve; an outlet of the second relief valve and the exhaust valve connected near one end; and connected near the other end to the inlet of the casing; An overload protection device characterized in that a sensor chamber is formed in the casing, and a sensor is slidably guided in the sensor chamber, and a switch that is opened and closed by the sensor is attached to the casing. . (2) In an overload protection device connected in the middle of a liquid path connecting a pump and a machine, an inlet connected to the outlet of the pump, a discharge port connected to the machine, and a liquid storage tank are connected to each other. a casing having a discharge port; the casing has a flow path connecting the suction port and the discharge port; and a valve body for opening and closing the flow path connecting the discharge port and the discharge port; a first relief valve having a cylinder hole to be inserted and a throttle hole formed in the sliding body and communicating between the suction port and the cylinder hole;
7 is connected to the valve chamber on the side opposite to the outlet, a relief valve body that is slidably guided in the valve chamber and opens and closes between the valve chamber and the cylinder hole, and a spring that presses the relief valve body.
A sensor device includes a relief valve, a sensor chamber in which one end communicates with the valve chamber of the second relief valve and the discharge port, and a switch attached to the gauging, and the sensor device slides inside the sensor chamber. The sensor has a movable piston-like sensor, a pin part provided on the opposite side of the sensor from the relief valve and slidably guided in a guide hole of the casing, and a spring that presses the sensor from the relief part side to the pin part side, A guide hole that guides the pin part is connected to the suction port, and when the pressure at the discharge port rises to a predetermined pressure or higher, the sliding body moves and the valve body opens the flow path, at which time the sensor detects the pin part. An overload characterized in that the sensor is pressed toward the pin side when the fluid pressure at the suction port decreases, and the switch is switched by the movement of the center point. Protective device.