JPH033368Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a safety device provided in a safety cover of a mortising machine that is automatically raised and lowered.

[Background of the invention] Safety covers have an important function in automated products that are lifted and lowered using the power of a lifting motor, instead of the lifting and lowering operations that were conventionally performed manually. With a manual machine, if you open the safety cover and turn on the power switch, there is a risk that the circular saw will rotate, but it will not descend, so the danger is not that high. However, when it comes to automatic machines, the circular saw rotates and descends, so if two people are working, the person in charge of setting the circular saw may turn on the power switch before the workpiece has been set, causing it to start up. There was a risk that this could happen. Also, it is very dangerous to open the safety cover while driving, and in this situation,
There was a need to stop operation. Furthermore, simply cutting off the power during operation would not cause the machine to stop immediately due to inertia, and it was necessary to stop the lift instantly.

[Purpose of invention]

The purpose of this invention is to eliminate the drawbacks of the conventional method, to prevent the motor from starting when the safety cover is open, and to instantly stop the rotation and cutting head of the circular saw when it is running. The goal is to improve the safety of automatic machines.

[Summary of the idea]

This invention has a detector installed in the part that locks with the rear cover when the front cover is opened, and a control circuit that does not start even if the operation switch is turned on when the detector is activated. If the machine starts, cut off the power to the circular saw and lifting motor,
Furthermore, the lifting motor is equipped with a timer circuit and is a control circuit that performs time control.

[Example of idea]

On the base 1 is a vise device 2 that holds the workpiece.
, and two guide bars 3 are installed vertically at the other end.
The upper end is held by a bridge 4. A lift motor 5 (M ₂ ) is provided on the bridge 4, and the cutting head 6 is moved up and down by means of power transmission means. The cutting head 6 has circular saws 7 and 8 for vertical and horizontal cutting,
It is equipped with a circular saw drive motor 9 (M ₁ ).
The above-mentioned lifting motor 5 and circular saw drive motor 9
is an electric circuit that is started and stopped by an operation switch 10 and a stop switch 11 provided on the bridge 4. A safety cover consisting of front and rear covers 12 and 13 is rotatably supported on the upper end of the cutting head 6, and each cover is pivotally attached by a hinge 14, and when the front cover 12 is rotated upward, Stand upside down on the rear cover 13. A detector 15 is provided at a locking portion of the rear cover 13, and the detector 15 is activated when the front cover 12 is turned upside down.

Next, the control operation will be explained using the block circuit diagram shown in FIG. This block circuit diagram operates based on electric signals from the operation switch and the detector, and includes a circular saw drive motor 9, a lifting motor 5,
This controls the operation and stopping of the system.

A normally open relay contact 24a is connected to the power line of the circular saw drive motor 9, and normally open relay contacts 25a and 26a are connected to the power line of the lifting motor 5. When the normally open relay contact 25a is closed, the lifting motor 5 rotates forward and the cutting head 6 is lowered, and when the normally open relay contact 26a is closed, the lifting motor 5 rotates in the reverse direction and the cutting head 6 is lowered. The electrical connections and mechanical structure are designed to rise.

These normally open relay contacts 24a, 25a, 26
The relay coils a correspond to 24, 25, and 26, respectively.

Operate the operation switch 10,
The output becomes logic "1" from logic "0", and if the detector 15 is not included, the output logic "0" of the detector 15 becomes logic "1" via the inverter 27, so the AND gate Flip-flop 17 is set through 16, and the Q output goes from logic ``0'' to ``1''. In response to this logic "1" signal, relay coils 24 and 25 are excited via amplifiers 18 and 19. Therefore, the normally open relay contacts 24a and 25a are closed, and power is supplied to the circular saw drive motor 9 and the lifting motor 5. That is, the circular saw rotates and the cutting head 6 descends.

The restart prohibition circuit includes detector 15 and inverter 2.
7. Operate the operation switch 10, which is composed of an AND gate 16 and a flip-flop 17, and the output of the operation switch 10 changes from logical "0" to "1", but when the detector 15 is turned on, the output of the detector 15 Since the logic "1" becomes a logic "0" through the inverter 27, the signal is blocked by the AND gate 16, the flip-flop 17 is not set, and the Q output becomes a logic "0". With a logic "0" signal, the relay coils 24 and 25 do not operate, the normally open relay contacts 24a and 25a remain open, and power is not supplied to the circular saw drive motor 9 and the lifting motor 5. In other words, the circular saw and the lifting motor will not start.

When the detector 15 is actuated while the cutting head 6 is lowered, a logic "1" signal is output, and the logic "1" output via the AND gate 20 resets the flip-flop 17, causing its Q output to become a logic "1". ” to logic “0” and amplifier 18,1
9, the relay coils 24 and 25 are demagnetized,
The normally open relay contacts 24a and 25a open, and the power to the circular saw drive motor 9 and lifting motor 5 is cut off. On the other hand, as the flip-flop 17 is reset, the Q output becomes logic "0", so the output of the AND gate 20 to which this signal is input is also inverted from logic "1" to "0", and the falling edge is sensed and the timer is activated. 21 is activated and emits a pulse with a preset time width _T1 . In response to the end signal of the pulse with a time width _T1 , the timer 22 is activated, emits a logic "1" pulse with a preset time width _T2 , and excites the relay coil 26 via the amplifier 23, so that it is normally open. The relay contact 26a is closed for a time _T2 to reverse the lifting motor 5, and the brake is applied to turn the cutting head 6.
to stop.

Here, time T ₁ is the normally open relay contact 25a, 2
It is the time for switching 6a, and the time T ₂ is
Preventing the downward inertia of the cutting head 6,
This is the time required to raise and lower the cutting head 6 slightly.

[Effect of idea]

According to the present invention, by installing a detector in the safety cover part, the motor will not start when the safety cover is open, and will stop if the safety cover is opened during operation. The safety of the tenoning work has been improved, and the cutting head can be stopped instantly by temporarily reversing the rotation of the lifting motor and applying the brakes to stop the lifting motor during the operation described above, making it even safer. I was able to improve my sexuality.

[Brief explanation of the drawing]

Figure 1 is a side view showing one embodiment of the present invention;
The figure is a block circuit diagram. In the figure, 1 is the base, 3 is the guide bar, 5
is a lifting motor, 6 is a cutting head, 7 is a vertical circular saw, 8 is a horizontal circular saw, 10 is an operation switch, 12 is a front cover, 13 is a rear cover, 15
is a detector, 16 and 20 are AND gates, 17 is a flip-flop, 18, 19, and 23 are amplifiers, 2
1 and 22 are timers, 24, 25, and 26 are relay coils, 24a, 25a, and 26a are normally open relay contacts, and 27 is an inverter.

Claims (1)

[Claims for Utility Model Registration] A circular saw and a cutting head having a circular saw drive motor are guided by a guide bar vertically installed from the base, and the lifting motor is driven by a control circuit having a lifting switch to lower the cutting head. In a mortising machine that automatically raises and lowers the saw, a safety cover that protects the circular saw part is installed on the cutting head so that it can be opened and closed freely, and a detection switch is installed on the cutting head to detect when the safety cover is opened or closed. The control circuit is equipped with a timer that cuts off the energization of the circular saw drive motor and the lifting motor in response to the safety cover detection signal of the switch, and operates for a certain period of time after cutting off the energization of the lifting motor. 1. A safety device for a tenon removal machine, characterized in that the control circuit is provided with a restart prohibition circuit that is activated by the control circuit, and prohibits restarting of a stopped circular saw drive motor and a lifting motor.