JPS601152B2 - Electric bolt tightening machine for shear bolts - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric bolt connecting machine that can efficiently temporarily straighten shear bolts.

A shear bolt is a bolt with a threaded part (tip), and if the mounting torque exceeds a specified value, the tip will twist and the parts will be attached together by the specified torque. Management can be performed accurately.

FIG. 1 is a cross-sectional view showing how this shear bolt is vertically attached, in which reference numeral 1 indicates an object to be fastened, 2 indicates a shear bolt, and 3 indicates a nut.

The shear bolt 2 has a tip 4 at its tip. 5
is an outer socket that engages with the nut 3.

Reference numeral 6 denotes an inner socket, which is located within the outer socket 5 and engages with the chip 4.

Reference numeral 7 designates a pin for ejecting the chip 4, which functions to eject the chip 4 remaining in the inner socket 6 after the main vertical operation is completed.

Such a shear bolt 2 vertical setting machine is made so that the tightening reaction force of the outer socket 5 is applied to the inner socket 6, and when a predetermined vertical setting torque is reached during final tightening, the chip 4 is sheared from its root.

As a result, the tightening torque during final tightening becomes constant. However, when temporarily tightening this shear bolt 2,
In other words, if you stop the motor before tip 4 is twisted,
Between outer socket 5 and nut 3 and inner socket 6
Because of the strong bond between the tip 4 and the tip 4, it becomes difficult to remove the vertical attachment machine.

As a result, temporary tightening work was not possible. Temporary tightening of bolts is essential for adjusting the looseness between each member, especially in construction-related work and bridge-related work. Conventionally, temporary tightening of bolts was performed using a temporary tightening machine (for example, an impact wrench, etc.). was going on.

This invention was made in view of these circumstances,
The first object of the present invention is to provide an electric bolt tightening machine for shear bolts whose main body can be removed from bolts and nuts extremely easily after temporary tightening, and the present vertical means. The second object is to provide a bolt tightening machine that can easily switch between temporary tightening and main tightening by adding the following.

In order to achieve such an object, the present invention provides an electric bolt attaching machine for shear bolts using a series-wound commutator motor, and a torque detecting means for detecting when the motor current exceeds a temporary vertical setting value. , voltage control means for lowering the voltage applied to the motor based on the output of the torque detection means; forward/reverse switching means for switching the current direction of one of the field and the armature of the motor; A forward/reverse control means outputs an output to the forward/reverse switching means to cause the electric motor to rotate in the forward or reverse direction at predetermined time intervals, and is configured to cause the electric motor to rotate in the forward or reverse direction at a low speed after the pre-tightening set torque. The present invention will be explained in detail below based on the drawings. FIG. 2 is a control circuit diagram showing one embodiment of the present invention.

This embodiment is equipped with a permanent tightening means and a temporary tightening means, and the two means can be switched. In the figure, reference numeral 10 is an AC power supply, 11 is a trigger switch, and 12 and 13 are a field and an armature forming a series-wound commutator motor. First, the temporary vertical means will be explained. 20 is a torque detection circuit that detects that the motor current has reached the tentative setting value; 30 is a voltage control circuit that lowers the voltage applied to the motor based on the output of this torque detection circuit 20; A forward/reverse switching circuit for switching the direction; 50 is a forward/reverse switching circuit that outputs an output from the torque detection circuit 20 to the forward/reverse switching circuit 401 through the delay circuit 34 to forward/reverse the motor at predetermined time intervals; It is a control circuit.

The torque detection circuit 20 includes a shunt resistor 21 connected in series to the armature 13, an amplifier 22 that amplifies a voltage change corresponding to the armature current of the shunt resistor 21, a timer 23, a comparator 24, and a torque detector 21. A setting device 25 is provided.

The timer 23 sends the output of the amplifier 22 to the comparator 24 after a certain period of time after the trigger switch 11 is turned on. This has the effect of preventing malfunction due to The torque setting device 25 sends to the comparator 24 a voltage corresponding to the temporary cotton setting torque at the end of temporary tightening. The comparator 24 is connected to the output voltage of the timer 23 and the torque setting device 2.
5 and outputs an on signal when the former is greater than the latter. Note that once the output voltage of the timer 23 exceeds the voltage of the torque setter, the comparator 24 continues to output an on signal until the trigger switch 11 is turned off. In addition, in a series-wound commutator motor, the armature current is approximately proportional to the tightening torque, so as the tightening of the nut progresses, the armature current gradually increases, and the output voltage of the timer 23, which is input to the comparator 24, also increases. It is gradually increasing. The voltage control circuit 30 includes a phase control thyristor circuit 31 interposed between the trigger switch 11 and the forward/reverse switching circuit 40, a low speed phase control circuit 32, and a switching circuit 33.
, a delay circuit 34 , and a gate cutoff circuit 35 .

Note that 60 is a phase control circuit for determining the temporary tightening speed, and this phase control circuit 60 generates a gate signal according to the phase set by the speed setting device 61, and this gate signal is passed through the switching circuit 33 during temporary tightening. and is sent to the siris evening circuit 31.

In addition to the phase control circuit 6, the gate cutoff circuit 35 stops generating the gate signal based on the gate cutoff signal generated by the output of the torque detection circuit 20, that is, the ON signal of the comparator 24. Therefore, at this time, thyristor circuit 3
1 is turned off and the motor stops -1. The low-speed phase control circuit 32 sends a gate signal having a smaller conduction rate than the phase circuit 60 to the switching circuit 33.

The delay circuit 34 sends the ON signal of the comparator 24 to the switching circuit 33 with a slight delay. The conversion circuit 33 is a delay circuit 34
The phase control circuit 6
A temporary vertical gate signal of 0 is sent to the thyristor circuit 31, and when the ON signal of the delay circuit 34 comes, the low speed phase control circuit 32
A low speed gate signal is sent to the thyristor circuit 31. That is, when it is detected that the armature current has reached the pre-tightening set value and the pre-tightening set torque, the temporary-tightening gate signal of the phase control circuit 60 is first stopped by the action of the gate cutoff circuit 35, and the thyristor circuit 31 is turned off. Temporarily cut off the armature current.

Then, after the set time of the delay circuit 34, the low-speed gate signal of the low-speed phase control circuit 32 is transferred to the thyristor circuit 3.
1 and the armature current is limited. Note that delay circuit 3
4 has the function of temporarily interrupting the armature current in consideration of the inertia of the rotating part when the motor rotation speed changes suddenly from the motor rotation speed during temporary tightening to the low rotation speed after the temporary tightening is completed. The forward/reverse switching circuit 40 includes four switching thyristors 41, 42, 43, and 44 forming a bridge circuit, and the forward/reverse thyristors 41 and 42 and the reverse thyristors 43 and 44 located in symmetrical positions are turned on simultaneously. Turn off. Between intermediate points a and b of this bridge circuit, a field winding 12 is connected to a final closing/temporary closing sliding door switch 6, respectively.
5 and 66. The real cotton/temporary tightening changeover switches 65 and 66 are normally returned so as to connect the Kaiji winding 12 to intermediate points a and b. In FIG. 2, when the electric motor rotates in the normal direction, the thyristors 41 and 42 are turned on, and the thyristors 43 and 44 are turned off. Further, when the rotation is reversed, the thyristors 41 and 42 are turned off, and the thyristors 43 and 44 are turned on. Forward/reverse control circuit 5 includes an astable multi-pipelator 51 which passes through a delay circuit 34 and outputs an on-signal at predetermined time intervals based on the on-signal of the comparator 24; A gate control circuit 52 is provided that turns on the reverse rotation side thyristors 43 and 44 and turns off the forward rotation side thyristors 41 and 42.

Note that this gate control circuit 52 is a multipipulator 51.
When the output is an off signal, the forward rotation side thyristors 41 and 42 are turned on, and the reverse rotation side thyristors 43 and 44 are turned off.
The temporary cotton means constructed as described above operates as follows. When the trigger switch 11 is turned on, the phase control circuit 60
A gate signal with a far current rate corresponding to the temporary tightening speed is sent to the thyristor circuit 31, and the forward rotation thyristors 41 and 42 are turned on. Therefore, current flows through the field 12 in the direction of the solid line arrow in the figure, causing the motor to rotate in the normal direction. At the moment when the trigger switch 11 is turned on, the motor is stopped and the back electromotive force of the armature is zero, so a large current flows. However, due to the action of the timer 23, the comparator 24 may
does not output an on signal. When the electric motor is started and temporary tightening progresses, and the armature current corresponds to the temporary tightening setting torque, the comparator 24 outputs an on signal and the phase control circuit 6 stops generating the temporary vertical gate signal. Thereafter, after a set time of the delay circuit 34, a low current is supplied to the field 12 and the armature 13 by the low speed gate signal of the low speed phase control circuit 32.
Further, a forward/reverse switching circuit 40 is activated by a signal from the delay circuit 34.
switches the direction of the current flowing through the field 12 between the forward rotation direction (in the direction of the solid line arrow in the figure) and the reverse direction (in the direction of the broken line arrow in the figure) at predetermined time intervals. Therefore, the electric motor repeats forward and reverse rotation at low speed, and this state is maintained until the trigger switch 11 is turned off. Next, the real cotton means will be explained.

The final tightening means is the aforementioned final tightening/temporary tightening switch 65, 66.
Consisted of. The changeover switches 65 and 66 are connected to disconnect the field 12 and intermediate points a and b, and apply the AC power supply 10 voltage directly to the direct circuit of the field 12 and armature 13. . Note that the changeover switches 65 and 66 are interlocked so that they open and close at the same time. Moreover, it goes without saying that the series commutator motor is an AC/DC motor. By using this cotton means, the motor current is no longer limited by the voltage control circuit 30, so the tightening torque increases, and the tip 4 of the shear port 2 (see Figure 1) is finally sheared, and the tightening is no longer possible. Completely terminate.

In the embodiments described above, the voltage control circuit 30 performs phase control using a thyristor, but the present invention can achieve the desired effect even when using other methods, such as resistance switching.

In addition, the main tightening means is configured to apply the AC power supply voltage 10 directly to the motor using the main tightening/temporary closing switches 65 and 66, but the present invention has a phase control circuit 60 that sets the armature current during temporary vertical tension. It can also be used when closing.

For example, during final tightening, the phase control circuit 60 of the gate cutoff circuit 35
It is also possible to cut off the input to the gate and output a gate signal with a high conduction rate. Note that the timer 23 is omitted, and instead a cushion start circuit is provided between the phase control circuit 60 and the speed setter 61 to keep the current low when the trigger switch 11 is turned on and to prevent the torque detection circuit 20 from malfunctioning. It is clear that it can also be done.

As described above, the present invention is configured such that during temporary tightening, the electric motor is rotated in the forward and reverse directions at low speed and at predetermined time intervals after reaching the temporary tightening set torque. Even if they are strongly engaged, there will be a moment when play will be formed between them during forward and reverse rotation, making it possible to easily remove the tightening machine. Therefore, the efficiency of temporary tightening of shear bolts is significantly improved. In addition, if you add a final tightening means and switch between actual vertical tightening and temporary tightening, you can use one vertical tightening machine to
Temporary vertical alignment can be performed, further improving work efficiency.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing how a shear bolt is tightened, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 12... Field, 13... Armature, 20
... Torque detection circuit, 30 ... Voltage control circuit, 40 ... Forward/reverse switching circuit, 50 ...
...Forward/reverse control circuit, 65, 66...Original...
Temporary closing switch. Purple 1st figure 2nd figure

Claims (1)

[Claims] 1. In an electric bolt tightening machine for shear bolts using a series commutator motor, a torque detection means for detecting that the motor current has reached a pre-tightening set value, and an output of this torque detection means voltage control means for lowering the voltage applied to the motor based on the voltage applied to the motor; forward/reverse switching means for switching the energization direction of one of the field of the motor and the armature; and output to the forward/reverse switching means based on the output of the torque detecting means. an electric bolt tightening machine for a shear bolt, comprising: forward/reverse control means for forward/reverse the motor at predetermined time intervals; and after a pre-tightening set torque, the motor is reversely forward/reverse at a low speed. 2. An electric bolt tightening machine for shear bolts using a series commutator motor, comprising a final tightening means and a temporary tightening means, and the temporary tightening means has a torque that detects that the motor current has reached the temporary tightening setting value. a detection means, a voltage control means for lowering the voltage applied to the motor based on the output of the torque detection means, a forward/reverse switching means for switching the energization direction of one of the field and the armature of the motor, and the output of the torque detection means. forward/reverse control means for outputting an output to the forward/reverse switching means based on the torque to rotate the electric motor in the forward or reverse direction at predetermined time intervals; - An electric bolt tightening machine for shear bolts, comprising a temporary tightening means, wherein the temporary tightening means rotates the electric motor in the forward and reverse directions at low speed after the temporary tightening setting torque is reached.