JPH043757Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to a safety device for preventing falling of an elevating body and unauthorized elevating and lowering operations in a press machine or the like.

(Prior Art) In conventional press machines, the elevating body is suspended by a chain or the like in order to prevent the elevating body from falling when the drive mechanism that drives the elevating body is damaged or malfunctions.

(Problems to be solved by the invention) In the case of the above-mentioned safety mechanism, there was a problem that the mechanism was complicated and the installation space increased.

An object of the present invention is to provide a compact safety device that prevents an elevating object from falling or unauthorized lifting/lowering operations in the event of damage to the drive mechanism for moving the elevating object up and down.

(Means for Solving the Problem) The safety device for an elevating object of the present invention extends between a fixed base that is installed so that it cannot be moved up and down, and an elevating object that is installed above this fixed base so that it can be moved up and down. At least one pair of safety cylinders are installed in parallel, and when the piston rod of a sub-cylinder installed across the upper fixed base installed above the elevating object so as not to be able to move up and down and the elevating object is damaged, A sensor for transmitting a detection signal is provided in a parallel flow path connecting both of the safety cylinders in parallel, and is actuated by the detection signal of the sensor to control the flow of pressure oil in the parallel flow path. It has a configuration in which a switching valve is provided for switching from a state in which pressure oil can flow to a state in which flow of pressure oil in the parallel flow path is disabled.

(Function) If the piston rod of the sub-cylinder installed between the elevating body installed above the fixed base so as to be movable up and down and the upper fixed base installed above the elevating body so as not to be movable up and down, is damaged, A detection signal from a sensor indicating that a switching valve provided in a parallel flow path that connects in parallel at least one pair of safety cylinders installed across the fixed base and the elevating body detects damage to the piston rod of the elevating cylinder. operated by
The elevating body is brought to an emergency stop by switching from a state in which pressure oil can flow in the parallel flow path to a state in which pressure oil cannot flow in the parallel flow path.

(Effects of the invention) According to the present invention, when an abnormality occurs in the elevating body drive mechanism, the flow of pressure oil between both safety cylinders is blocked and the elevating body is brought to an emergency stop, thereby preventing the elevating body from falling or incorrectly lifting or lowering the body. This has the effect of increasing work safety by preventing

(Example) Next, an example of the present invention will be described with reference to the drawings.

In the press P, a fixed base 2 for attaching a lower mold (not shown) is installed horizontally on a base 1, and four tie bars 3 are installed on each of the fixed bases 2 on the four corners of the base 1. They are arranged vertically, passing through each corner 2a.

The four corners of the upper fixed base 4 installed above the fixed base 2 are fixed to the upper end of each tie bar 3, and the main cylinder 5 is attached to the center of the upper fixed base 4. A pair of sub-cylinders 6, 6 are attached to both ends facing downward, and a ram 7 connected to the main cylinder 5 is attached to the center of the upper fixed base 4 so as to be movable up and down.

An elevating body 8, which has a substantially rectangular planar shape and is installed horizontally between the fixed base 2 and the upper fixed base 4 in order to attach the upper mold, is formed at each of its four corners 8a, and the tie bars 3 are respectively slid. It is held movably up and down with respect to each tie bar 3 via a slide member 8b that is inserted through the slide member 8b, and its left and right ends are respectively connected to threaded portions formed at the lower ends of the piston shafts 6a of both sub-cylinders 6. ing. The elevating body 8 is lowered by the lowering movement of the ram 7 and the piston shafts 6a of both sub-cylinders 6, and raised by the rising movement of both piston shafts 6a.

A pair of limit switches (sensors) 20 each provided to detect the presence or absence of an abnormality in both sub-cylinders 6 and issue an emergency stop signal when an abnormality occurs.
20 is attached near the lower ends of the piston rods 6a of both sub-cylinders 6 so that the detection pieces 20a come into contact with the upper surface of the elevating body 8 and are pushed up, and the piston rods 6a of the sub-cylinders 6 are located at the position where the limit switch 20 is attached. When the piston rod 6a is damaged at a lower position, the portion of the piston rod 6a other than the lower end connected to the elevating body 8 separates from the elevating body 8, and the limit switch 2
0 detection piece 20a is released from the upper surface of the elevating body 8, the contact point of the limit switch 20 is switched, and the limit switch 20 sends a detection signal to emergency stop the elevating body 8.

A pair of first and second safety cylinders 9A and 9B of the same standard are installed in parallel across the fixed base 2 and the elevating body 8, and are located at both left and right ends of the front end of the elevating body 8 and at the rear end. Each safety cylinder 9A,
The lower end portions of piston rods 10, 10, which are vertically slidably inserted into the cylinder tubes 11A, 11B of 9B, are respectively connected to the corner portions of the fixed base 2. Cylinder tube 11A of the first and second safety cylinders 9A and 9B,
The interior of the piston rod 11B is divided into two upper and lower chambers by pistons 10a, 10a which protrude near the center of the piston rod 10 and are tightly fitted into the cylinder tubes 11A, 11B so as to be able to slide up and down, respectively. Inside the cylinder tube 11A of 9A, there is an upper oil chamber 12A and a lower oil chamber 13.
An upper oil chamber 12B and a lower oil chamber 13B are respectively formed in the cylinder tube 11B of the second safety cylinder 9B.

First and second safety cylinders 9A and 9B on the front side and first and second safety cylinders 9A and 9B on the rear side
A parallel flow path 14 connecting these in parallel is provided to allow the steady lifting and lowering movement of the lifting body 8 and to make an emergency stop of the lifting body 8.
A 2-port, 4-position switching valve 15 that is activated by an emergency stop signal from the limit switch 20 is connected in the middle of the switching valve 15 to allow or prevent the flow of pressure oil in the parallel flow path 14. Part 15
A is connected to both limit switches 20 via signal transmission circuits 24, respectively. The upper oil chamber 12A of the first safety cylinder 9A is connected to the P port of the switching valve 15 via a pipe 14a, and the lower oil chamber 13A of the first safety cylinder 9A is connected to the P port of the switching valve 15 via a pipe 14b. Connected to T port. Further, the upper oil chamber 12B of the second safety cylinder 9B is connected to the A port of the switching valve 15 via the pipe 14c, and the lower oil chamber 13B of the second safety cylinder 9B
is connected to the B port of the switching valve 15 via a pipe line 14d. The pipes 14c and 14d are connected to a return oil tank 23 via a relief valve 21 and a check valve 22, respectively.

When the elevating body 8 is repeating the vertical movement normally, the switching valve 15 is connected to the P port, the B port, and
The T port and the A port are held in the normal position where they are communicated with each other, and the cylinder tubes 11A and 1
1B rises together with the elevating body 8, and the piston 10a of the piston rod 10 moves into the cylinder tube 11.
A, 11B, the pressure oil in the lower oil chamber 13A of the first safety cylinder 9A moves to the lower part of the pipe line 1.
4b and 14c into the lower oil chamber 12B of the second safety cylinder 9B, and the pressure oil in the lower oil chamber 13B of the second safety cylinder 9B is transferred to the pipe line 14.
d and 14a into the upper oil chamber 12A of the first safety cylinder 9A, and the pressure oil is allowed to flow in opposite directions within the parallel flow path 14. Additionally, as the piston 10a of the piston rod 10 moves to the upper part of the cylinder tubes 11A and 11B, the pressure oil in the upper oil chamber 12A of the first safety cylinder 9A flows into the lower oil chamber 13B of the second safety cylinder 9B. Upper oil chamber 12B of the second safety cylinder 9B
The pressure oil inside the lower oil chamber 13 of the first safety cylinder 9A
A, the pressure oil is allowed to flow in opposite directions within the parallel flow path 14, and each safety cylinder 9A,
9B operates normally, and the repeated lifting and lowering operations of the lifting platform 8 are performed normally.

Then, the piston rods 6 of both sub-cylinders 6
When one of the valves a is damaged, an emergency stop signal is sent from the limit switch 20 which detects this damage, and the switching valve 15 is activated. When the switching valve 15 operates, the P port and the A port and the T port and the B port are connected to each other, and the first safety cylinder 9A is connected to the first safety cylinder 9A.
The upper oil chamber 12A and the upper oil chamber 12B of the second safety cylinder 9B communicate with each other via pipes 14a and 14c, and the lower oil chamber 1 of the first safety cylinder 9A
3A and the lower oil chamber 13B of the second safety cylinder 9B are communicated via pipes 14b and 14d, and the flow of pressure oil in the parallel flow path 14 is disabled, so that both piston rods 10 immediately move up and down. , and the elevating body 8 comes to an emergency stop. Also, limit switch 20
In response to the emergency stop signal, the hydraulic pump of the main circuit (not shown) in which the main cylinder and sub cylinder 6 are incorporated comes to an emergency stop.

Next, the operation and effects of the embodiment having the above configuration will be explained.

In this example, a fixed base 2 installed so that it cannot be raised or lowered,
Two pairs of safety cylinders 9A, 9 are connected to the elevating body 8 installed above the fixed base 2 so as to be movable up and down.
The piston rod 6 of the sub-cylinder 6 is constructed in parallel to the upper fixed base 4 which is installed above the elevating body 8 so that it cannot move up and down, and the elevating body 8.
A is equipped with a limit switch 20 that sends out a detection signal when the piston rod 6a is damaged, and a limit switch 20 that is activated by the detection signal of the limit switch 20 is installed in the parallel flow path 4 that connects each pair of safety cylinders 9A and 9B in parallel. A switching valve 15 is provided for switching the parallel flow path 14 from a state in which pressure oil can flow in the parallel flow path 14 to a state in which pressure oil cannot flow in the parallel flow path 14.

Therefore, when an abnormality occurs in the sub-cylinder 6, the elevating body 8 is immediately brought to an emergency stop by switching the parallel flow path 14, thereby preventing the elevating body 8 from falling or incorrectly moving up and down, thereby improving the safety of press work. In addition, the mechanism for emergency stopping the elevating body 8 can be simplified and made more compact.

In addition, in the above embodiment, both safety cylinders 9
Attach A and 9B facing upward on the fixed base 2,
Piston rod 10 of both safety cylinders 9A and 9B
may be connected to the elevating body 8, respectively.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a hydraulic circuit diagram of a safety device, FIG. 2 is a front view of the press, and FIG. 3 is a side view. 2...Fixed base, 8...Elevating body, 9A, 9B...
Safety cylinder, 14...Parallel flow path, 15...Switching valve.

Claims (1)

[Scope of utility model registration request] At least one pair of safety cylinders is installed in parallel across a fixed base that is installed so that it cannot move up and down, and an elevating body that is installed above the fixed base so that it can move up and down; A sensor is provided that sends a detection signal when the piston rod of the sub-cylinder installed across the upper fixed base, which is installed so as not to be able to move up and down, and the above-mentioned elevating body is damaged. There is a switch in the parallel flow path which is activated by the detection signal of the sensor to change the parallel flow path from a state where pressure oil can flow in the parallel flow path to a state where pressure oil cannot flow within the parallel flow path. A safety device for an ascending and descending object, characterized by being provided with a switching valve for switching the state.