JP2587758B2 - Torque wrench tightening control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tightening control device for a torque wrench such as an impact wrench or a hydraulic wrench.

[0002]

2. Description of the Related Art In an impact wrench, it is necessary to detect a striking state in order to accurately control a tightening torque or to accurately grasp the number of members who have completed a tightening operation. Conventionally, the impact state is detected by a method in which a sensor is attached to the main shaft of the air motor to detect reversal of the main shaft. However, in this method, it is necessary to dispose a sensor for detecting the normal rotation and the reverse rotation inside the impact wrench, so that there is a disadvantage that the size of the device is increased and the cost is increased.

For this reason, it is conceivable to adopt a method in which the supply pressure is detected, and the impact state is detected when the impact wrench is activated when the supply pressure falls below a reference value. However, this method has a disadvantage that it is impossible to distinguish whether the impact wrench is in a no-load rotation state or a hit state. This is because the pressure difference generated between the no-load rotation state and the impact state is smaller than the pressure fluctuation inevitably generated in the air supply source, and it is impossible to identify the difference.

Accordingly, a main object of the present invention is to provide a torque wrench tightening control device capable of accurately controlling a tightening torque in a torque wrench.

A further object of the present invention is to provide a torque wrench tightening control device capable of accurately grasping the number of members whose tightening work has been completed under accurate torque control as described above. Is to do.

[0006]

According to a first aspect of the present invention, there is provided a torque wrench tightening control device, comprising: a pressure change rate grasping means for grasping a change rate of an air supply pressure supplied to the torque wrench; A hitting signal output means for outputting a hitting signal longer than the hitting interval when the hitting value is reached, and measuring the hitting signal output continuation time, and when the timing value reaches the set time, a fastening completion signal is output. The present invention is characterized in that a timer for outputting the output signal and an air supply stopping means for closing an air supply passage to the torque wrench by outputting the tightening completion signal are provided.

According to a second aspect of the present invention, there is provided a torque wrench tightening control device which counts the tightening completion signal and outputs a predetermined number of tightening completion signals when the count value reaches a set number. It is characterized by that.

[0008]

In the torque wrench tightening control device according to the first aspect, the supply pressure is maintained at a specific pressure during the no-load rotation.
Since the supply pressure does not change with time, no striking signal is output. On the other hand, in the striking state, the supply pressure changes by a certain degree or more each time a striking occurs, and a striking signal is output based on this change. And at this time, between the blows
Outputs the impact signal for a longer time than the interval
Therefore, this impact signal is output as a continuous signal from the first shot.
Is forced. The output continuation time of the output striking signal is measured, and when these reach a set value, the air supply is stopped, so that accurate tightening torque control can be performed.

In the torque wrench tightening control device according to the second aspect of the present invention, the number of tightened members to be tightened can be counted, and it can be recognized that the number of tightened members has reached the set number. The number of members can be managed.

[0010]

Next, a specific embodiment of a torque wrench tightening control device according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram of the entire structure. In FIG. 1, reference numeral 1 denotes an air supply source, 2 denotes an air hose, and 3 denotes an impact wrench. An electromagnetic valve 4, a check valve 5, and a pressure transducer 6 are provided in this order. The check valve 5 is for preventing a trouble caused by a pressure drop on the air supply source 1 side. Also, in the figure, reference numeral 7 denotes a control device. The control device 7 includes an input port 8 connected to the pressure transducer 6, an output port 9 connected to the solenoid valve 4, and a plurality of input members for setting the number of members. , And output ports 11 and 12 for outputting a predetermined number of members tightening completion signal and an NG signal.

FIG. 2 shows a functional block diagram of the control device 7. The pressure signal from the pressure transducer 6 is input to the pressure signal amplifier 21 and then output to the pressure change rate grasping unit 22 and the impact signal output unit 23. The striking signal output unit 23 includes a detection level setting unit 24, a signal output time changing unit 25, and a reset level setting unit 26, and outputs a striking signal. The function thereof will be described later. This striking signal is transmitted to the timer 28
The output continuation time is measured by, which outputs the tightening completion signal when it reaches a set value in the setting unit 30.
Then, based on the tightening completion signal, the electromagnetic valve shut-off unit 31 closes the electromagnetic valve 4. On the other hand, the control device 7
Is provided with a member number setting unit 32 composed of a digital switch and a member number counting unit 33. The member number counting unit 33 counts the above-described tightening completion signal.
When the set value is reached, a predetermined number of members fastening completion signal is output, and a series of fastening operations can be stopped.
Numeral 34 denotes a remaining number display portion, which is used to display the number of remaining tightenings to be performed by LEDs. The number-of-members setting unit 32 may be singular or plural. Further, the control device 7 is further provided with a timer section 35, which is used when a predetermined number of members tightening completion signal is not output within a predetermined time after being reset by a start signal at the time of starting a series of tightening operations. To
It outputs an NG signal. 36 is a timer adjustment unit, and 37 is a power supply unit.

Next, an operation state of the control device will be described with reference to FIG. First, FIG. 3A shows an output signal from the pressure transducer 6, and from the signal, the pressure change rate grasping unit 22 extracts only the AC component as a pressure fluctuation signal. This pressure fluctuation signal has no fluctuation at the time of stop, a large negative fluctuation level is obtained when the lever is open, a slight fluctuation at the time of free running (no load rotation), and a small fluctuation at the time of impact as shown in FIG. It has the characteristic that large positive fluctuations and small negative fluctuations are repeated for each impact. Therefore, the impact signal output unit 23
Then, the negative fluctuation when the lever is opened is caused by the reset level setting section 26
When the reset level is reached, the timer 28 is reset and the detection of the hit state is started. Now, the above detection
Set detection level or more positive change in the level setting section 24, that is, when striking occurs, from the striking signal output section 23, the striking signal as shown in FIG. 2 (c) is outputted for a predetermined time T ₄ . The signal output time T ₄ is be one that is set by the signal output time changing section 25, the striking
It is set longer than the generation interval T _3. Then, the striking signal is output as a continuous signal from the first stroke. In order timer 28 thereof, the measured output signal duration, when this has reached the set time T _1, closes the electromagnetic valve 4 and outputs a completion signal tightening, then closing the lever (Fig. 3 ( d) (e)). The solenoid valve 4
After closing, automatically opens again after a predetermined time T ₂ has elapsed. Then, the above-described tightening operation is repeated a predetermined number of times, and when the tightening completion signal counted in the number counting section 33 reaches a set value, a predetermined number of tightening completion signal is output. Complete.

[0014]

The embodiment of the torque wrench tightening control device of the present invention has been described above. However, the torque wrench tightening control device of the present invention is not limited to the above-described embodiment, but may be variously modified. Can be implemented. For example detects the striking interval T ₃ in the above, when the striking interval is longer than the reference time is not considered a hit this, if it is a disturbance
However, a measure such as resetting the timer 28 may be taken. Furthermore, in the above, the rate of pressure change is
I got it by extracting only the minute, but this adopted another method
May be taken out.

[0016]

As described above, in the torque wrench tightening control device according to the first aspect, instead of detecting the supply pressure as in the prior art, the impact state is detected based on a change in the supply pressure. Therefore, the tightening torque can be accurately controlled.

Further, according to the torque wrench tightening control device of the second aspect, in addition to the torque control, the number of members can be accurately controlled, which is convenient in use.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an overall configuration of an embodiment of a torque wrench tightening control device of the present invention.

FIG. 2 is a block diagram showing the control configuration.

FIG. 3 is a time chart showing the operation state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Air supply source 3 Impact wrench 4 Solenoid valve 6 Pressure transducer 7 Control device 22 Pressure change rate grasping part 23 Striking signal output part 30 Timer 31 Solenoid valve shutoff part 32 Number setting part 33 Number counting part

Claims (2)

(57) [Claims] 1. A pressure change rate grasping means for grasping a change rate of an air supply pressure supplied to a torque wrench, and outputting a striking signal for a time longer than a striking interval when the rate of change reaches a reference value. A striking signal output means, a timer for measuring the duration of the striking signal output, and outputting a tightening completion signal when the measured time reaches a set time; and supplying air to the torque wrench by outputting the tightening completion signal. A tightening control device for a torque wrench, further comprising an air supply stopping means for closing a passage. 2. A number counting means for counting the fastening completion signal and outputting a predetermined number fastening completion signal when the count value reaches a set number. Luc wrench tightening control device.