JPS5831642Y2 - Screw tightening alarm device - Google Patents

Description

[Detailed description of the invention] This invention relates to a screw tightening failure detection device for a device that stops the rotation of the screwdriver when the rotational torque of the screwdriver reaches a certain value. In this case, if the rotational torque of the screwdriver becomes large at an early stage, this is displayed to indicate that the screw is not completely tightened.

When tightening a screw to a base material with a screwdriver, there is a known device that detects when the rotational torque of the screwdriver reaches a certain value and stops the rotation of the screwdriver.

In this device, the driver control circuit that controls the drive of the screwdriver may malfunction and issue a signal to stop the screwdriver even though the screw has not been sufficiently tightened by the screwdriver, or the base material may be partially hard. If the rotational torque increases early, the screwdriver will stop rotating even though the screws are not completely tightened.

Therefore, the present invention aims to prevent screw tightening failure by issuing a warning in such a case.

An embodiment of the present invention will be described below with reference to the drawings.

As shown in the figure, a series circuit consisting of a relay 3 and a switch 4 is connected between AC power supply terminals 1 and 2.

A timer 5 is connected in parallel to this relay, which starts operating a certain period of time after the switch 40 is turned on.

A first contact 5a is provided which becomes open when the timer 5 starts operating.

On the other hand, when the rotation of the driver 6 reaches a certain value, a driver control circuit 7 is provided to detect this and stop the rotation of the driver 6.

This driver control circuit 7 starts operating when current flows through the relay 3 and the contact 3a is closed.

When the driver control circuit 7 detects that the rotational torque of the driver 6 has reached a certain value, the second contact 7a closes.

This contact 7a, the contact 5a, and the relay 8 are connected in series and connected in parallel to the relay 3.

Contact 8 of relay 8 is connected in parallel to the series circuit of contacts 5a and 7a.
a is connected.

An alarm element 9 such as an indicator lamp or a buzzer is connected in series to this contact 8a.

When switch 4 is turned on, current flows through relay 3 and contact 3
a b5 The same circuit 7 starts operation □ and the driver 6 starts rotating.

After a certain period of time, the timer 5 starts operating, which opens the contact 5a.

Until the contact 5a opens, the contact 7a remains open, so no current flows through the relay 8.

The screw is tightened by the screwdriver 6, and when the rotational torque reaches a certain value, a signal is output and the rotation of the screwdriver 6 is stopped.

At this time, contact 7a is closed, but since contact 5a is open, no current flows through relay 8.

This completes one operation. Now, let us consider a case where the base material is partially stiff and the rotational torque reaches a certain value early, or a malfunction causes the driver control circuit 7 to issue a driver stop signal early.

The above-mentioned early period means until the timer 5 starts operating.

In this case, when contact 7a closes, since contact 5a is also closed, current flows to relay 8, closing contact 8a, and '
) V-8 is self-holding.

As a result, the alarm element 9 is activated to notify that the screw tightening is incomplete.

As described above, according to the present invention, if the rotation of the screwdriver is stopped prematurely by mistake, this can be notified by the alarm element.

[Brief explanation of drawings]

The figure is a circuit diagram of a screw tightening failure alarm device according to an embodiment of the present invention. 1.2...Power terminal, 3.8...Relay, 5...Timer 5a...First contact, 7a... Second contacts, 3a, 8a...
...Contact, 9...Alarm element, 6...
Driver 7...Driver control circuit, 4.
·····switch.

Claims (1)

[Scope of utility model registration request] A driver control circuit is provided that detects when the rotational torque of the screwdriver reaches a certain value and stops the driver from pivoting.After the switch is turned on, the driver control circuit is driven to start rotating the screwdriver, and the switch is activated. A timer is provided that starts operating at -m intervals after the timer is turned on, and when this timer is activated, the first contact that opens and the driver control circuit detect that the rotational torque of the screwdriver has reached a certain value. 2nd state which becomes closed state when
and a relay are connected in series, the contact of the relay is connected in parallel to the series circuit of the first contact and the second contact, and an alarm element is connected in series to the contact of the relay. Screw tightening failure detection device.