JPS5835100A - Overload safety device of press machine - Google Patents

Abstract

PURPOSE:To obtain a safety device which operates securely and stably by providing a coupling screw which break by an overload and a fuse to projection parts of the bracket of a rotating shaft on a machine frame where power is transmitted and an arm for power transmission rotatable on said shaft respectively. CONSTITUTION:Power is transmitted from the eccentric pin 2 of an eccentric plate 1 on the rotating shaft of a press machine equipped with an overload safety device through a coupling rod 3, an arm 8, a coupling screw 10, a bracket 9, a knock-out shaft 5, and a roll 6. When an overload operates upon a knock- out pin 7 in elevation, the screw 10 breaks. Then, a fuse 12 fixed at one end to a projection part 8a and also fixed at the other end to a projection part 9a through an insulating plate 11 is broken by a positive and a negative connection power source for the machine frame 13 and bracket 9 because both the projection parts increase in their interval. Therefore, the current flowed through the relay 16 of a constant voltage device 15 is cut off and the relay 16 is switched to connect with an output terminal 18; and a press operating circuit is turned off to stop press work.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overload safety device in a press machine.

Conventionally, in a press machine, a device for detecting when an overload is applied to a knockout device, etc. has a part in the mechanism that causes displacement due to overload, and the displacement is detected by a proximity switch, optical switch, or limit switch. was detected. However, both detectors have the drawback of being prone to malfunction. For example, a proximity switch detects the movement of another ferromagnetic material and generates a false signal, an optical switch detects the optical path blocked by a foreign object and does not output a signal, and a limit switch detects a contact failure. This often caused the detector itself to malfunction.

An object of the present invention is to eliminate these drawbacks and provide an overload safety device for a press machine that operates reliably and is highly stable. Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, a press machine equipped with an overload safety device (4) is shown. An eccentric plate (1) is fixed to the rotating shaft of the press, and an eccentric pin (2) installed upright on the eccentric plate (1) and an overload safety device (4) installed on the knockout shaft (5) are connected to a connecting rod ( 3) is connected. Eccentric pin (2
) rotates with the rotating shaft, connecting rod (3)
is rotatably installed in the aircraft OJ through the overload safety gear (4).
6) is fixedly attached to the arm that rotatably holds it. The roll (6) is in contact with the lower end surface of the knockout pin (7) which is provided on the hubless bolster so that it can move up and down. Low 1 due to the reciprocating rotational movement of the knockout shaft (5)
The knockout pin (7) moves up and down via the lever (6). The slide of the press and the rotation axis are synchronized, and when the slide moves down and up, the knockout pin (
7) begins to rise. In Figure 2, details of the overload safety device (4) are shown.

An arm (8) to which a connecting rod (3) is connected is rotatably provided on the knockout shaft (5). Moreover, the bracket (9) is fixed with a key.

The protrusion (8a) of the arm (8) and the protrusion (9a) of the bracket (9) face each other in a plane perpendicular to the direction of torque action. A connecting screw α is provided passing through these protrusions (8a) (9a), and the protrusions (8a) (
9a) and are fixed with nuts etc.

A small diameter portion is provided in the center of the connecting screw OI, which breaks when a load exceeding a predetermined torque is applied to the knockout shaft (5), thereby transmitting torque from the team (8) to the bracket (9). It is designed to cut off the Hughes (12)
I has one end fixed to the protrusion (8a) of the arm (8),
Connect the other end to the protrusion (9) of the bracket (9) through the insulating wall.
a) is fixed. Heath Q21 insulation plate α1)
One end fixed through is connected to a positive power source, and the press body 031 is connected to a negative power source. When an overload acts between the arm (8) and the bracket (9), the connecting screw OQ breaks and the distance between the protrusions (8a) and (9a) increases, causing the fuse a3 to break. The fuse (12) is protected by a vinyl tube (not shown), etc. Opposing surfaces of the projections (8a) and (9a) may be in contact with each other.

In FIG. 3, an electric circuit attached to the overload safety device (4) is shown. The constant voltage device α9 is an earth leakage breaker (
It is connected to an AC 100V power source via a plug 141 (a7). Positive 12 for constant voltage device a51
There are output terminals for V and zero V. The aforementioned heater O3 and relay a0 are connected in series between these two terminals. Relay αe has output terminal 0 when its coil is energized.
81 is disconnected, and when the coil is not energized, the output terminal a
Switch from polite to intimate. The output terminal α8) is connected to a circuit that stops the operation of the press.Next, the operation will be described. In Figures 1 to 3,
Connecting rod (3), arm (8), connecting screw Ql, bracket (9) from eccentric pin (2) of eccentric plate (1)
), when power is transmitted through the knockout shaft (5) and roll (6) and an overload is applied to the knockout pin (7) while the knockout pin (7) is rising, the connecting screw a breaks and at the same time heats up. az is broken O Heat from the positive 12V terminal of the constant voltage device α9, <aa
, the direct current flowing to the zero V terminal via relay αe is cut off, the relay mark A is switched and output terminals 08 are connected, and the press operation circuit is cut off to stop the press. Since the current that is constantly flowing is a low voltage of 12 V DC, there is no risk of an accident even if an electric shock occurs, and furthermore, the earth leakage breaker α operates, so it is safe.

Although the above description has been made regarding an example in which the present device is provided on the knockout shaft, it can also be applied to other rotational torque transmission parts.

As is clear from the above description, the present invention has a simple structure, is easy to install and handle, moves quickly and reliably, and does not have the detector itself malfunctioning like other detectors. ,
It has great practical effects and advantages, such as high vibration resistance and fewer failures.

[Brief explanation of drawings]

Fig. 1 is a side view of a greaseless machine equipped with the device of the embodiment, Fig. 2 is a diagram showing the structure of the embodiment, (a3 is a side view, (
1)) is a front view, and Figure 3 is an electrical circuit diagram. 1 is an eccentric plate, 2 is an eccentric pin, 3 is a connecting rod,
4 is an overload safety device, 5 is a knocker'1 door shaft, 6 is a roll, 7 is a knockout pin, 8 is an arm, 8a is a protrusion, 9 is a bracket, 9a is a protrusion, 1o is a connecting screw,
11 is an insulating plate, 12 is a heater, 13 is a fuselage body, 14 is an earth leakage breaker, 15 is a constant voltage device, 16 is a relay, 17 is a plug, and 18 is an output terminal. Patent Applicant AIDA Eng-Alling Co., Ltd. Representative Association 1) Keinosuke

Claims (1)

[Claims] In a press machine, a bracket is fixed to a shaft that is rotatably provided on a machine body and that transmits power, an arm that is rotatably connected to a side that transmits power is provided on the shaft, and the arm and the bracket are rotatably provided. The two protrusions are each provided with protrusions facing each other in a plane perpendicular to the direction of torque action, and both protrusions are connected to a connecting screw having a portion that ruptures with a predetermined torque, one end of which is directly attached, and the other end of which is provided with an insulating plate. An overload safety device for a press machine, characterized in that the device is connected to a fuse attached via a fuse.