JPH0344397Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a safety device for a press machine.

Conventional safety devices include a light beam type safety device placed on the front of the machine to stop the ram if a part of the human body blocks the light beam while the ram is descending. In this case, the ram was a mechanism that would stop even if a molded product, jig, etc., other than the human body, blocked the light beam. In the case of press brakes, most of the work is done while holding the molded product by hand, and the molded product itself may block the light, so installing a light beam safety device will greatly impair work efficiency. It is.

The present invention was developed in view of the above circumstances, and its purpose is to set a safety range that cannot be touched by humans, and to disable the safety device when the tip of the punch is within this safety range. The purpose is to enable work to be carried out safely without impairing workability.

Hereinafter, the present invention will be explained with reference to the drawings. In the drawing, 5 is a press brake body, and 4 is a die base. The press brake body 5 is provided with a ram 1 that is raised and lowered by a foot switch or the like.
A punch 2 is attached to the ram 1, and a die 3 is attached to the die base 4. In the drawing, reference numeral 6 denotes a light beam type safety device, and numeral 7 denotes a light receiver. When the light beam emitted from the light emitter 6 to the light receiver 7 is blocked, the ram 1 is stopped. 1 in the drawing
0 is a rotary encoder, which is a ram position detector for detecting the ram position of a synchronizer or the like.

The output side of this ram position detector 10 and the pushbutton 9 are connected to the input side of a counter circuit 11, and the output side of the counter circuit 11 is connected to one input side of a comparison circuit 12, and the comparison circuit 12
The other input side of is connected to the output side of the safety margin setting device 13. The output side of the comparison circuit 12 is connected to the input side of the safety margin signal output circuit 14, and the count set flag output P and the safety margin output Q are outputted from the output side of the safety margin signal output circuit 14. P and Q are input to a safety device circuit 15.

Next, the operation will be explained.

The safety range setting device 13 is set to output when the range from the lower limit of the ram to the tip of the punch is below the safety range L. This safety area L is dimensioned so that it cannot be accessed by human hands. Further, as shown in FIG. 4, at the lower limit position of the ram, that is, when the punch 2 hits the die 3, the counter value of the counter circuit 11 is set to 0 (origin) and a counter set flag is output.
The counter value by which the ram 1 is driven is incremented from the bottom dead center.

When the tip of the punch 2 is within the safety range L, an output is sent to the safety device circuit 15 to disable the safety device, and when the tip of the punch 2 is outside the safety range L, the safety device is enabled. Therefore, when holding the molded product by hand or when the molded product itself blocks light, stop the ram 1 within the safety range L, place the molded product on the die 3, and lower the ram 1 again. It is safe to do the work, and the work efficiency will not be affected.

When the power is turned on, the ram 1 is only capable of inching operation, and any stroke other than inching is not possible unless the operator presses the push button 9 at the bottom dead center and the counter set flag is output.

If the operator accidentally presses the pushbutton 9 before the lower limit, when the ram 1 descends in the next cycle, the counter value will operate beyond the origin, and in this case, the counter set flag will be dropped and a safety range signal will be output. The circuit 14 is dropped to allow the ram 1 to lower.

As described in detail above, the present invention includes a counter means for measuring the upward distance of the punch 2 from the lower limit position of the ram 1 where the tip of the punch 2 attached to the ram 1 contacts the die 3, and a counter means for measuring the upward distance of the punch 2 from the lower limit position of the ram 1. The raised position of the ram 1 from 2 to 2 is set as a safety range L to a point where a human hand cannot enter between the die 3 and the punch 2, and when the tip of the punch 2 is within this safety range L, this is detected and output. Since the configuration includes a safety margin signal output means for outputting a signal and a safety device circuit 15 for disabling the safety device in response to an output signal from the safety margin signal output means, the punch 2 caused by the vertical movement of the ram 1 When the position of the tip of the punch 2 and the die 3 is in the safety range L where the dimension between the punch 2 and the die 3 is such that human hands cannot enter, the output means is output from the safety range signal output means to activate the safety device. Can be disabled. Therefore, when holding the molded product by hand or when the molded product itself blocks the light beam of the safety device, stop the punch 2 within this safety range L, place the molded product on the die 3, and then move the ram 1 again. By lowering it, work can be done safely and without compromising work efficiency.

[Brief explanation of the drawing]

FIG. 1 is a front view of the press brake, FIG. 2 is a view taken from the direction of FIG. It is an explanatory diagram. 1 is the ram, 2 is the punch, and 15 is the safety device circuit.

Claims (1)

[Scope of utility model registration request] A counter means for measuring the upward distance of the punch 2 from the lower limit position of the ram 1 where the tip of the punch 2 attached to the ram 1 contacts the die 3; The safety range L is the raised position of ram 1 to a dimension where it cannot be touched.
and a safety range signal output means that detects when the tip of the punch 2 is in this safety range L and outputs an output signal, and disables the safety device by receiving an output signal from this safety range signal output means. Safety device circuit 1
5. A safety device for a press machine, characterized by comprising: