JPS60177876A - Clutch type clamping tool - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a clutch disengagement detection device for a clutch-type tightening tool.

In the conventional clutch-type tightening tool, when the clutch is disengaged, a stop signal generation switch is turned on to stop the electric motor, and after disengagement, the clutch is pressed and engaged again by the pressing force of the tightening force adjustment spring. At the same time, the suppressing force was used to cut off the stop signal generating switch.

However, in the case of the prior art, at least one of the switching on and off of the stop signal generating switch' is determined by the disengagement speed of the clutch or the pressing force of the tightening force adjustment spring, and the switching on or off at this high speed is determined by the disengaging speed of the clutch or the pressing force of the tightening force adjustment spring. This caused problems such as chattering and high-speed movement of the movable piece inside the switch, resulting in damage to the contacts and breakage of the movable piece. In particular, when the closing or shutting speed is determined by the pressing force of the clamping force adjustment spring, the reliability of the stop signal generation switch decreases as the required clamping force increases. Ta.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the drawbacks of the prior art, increase the reliability of a stop signal generating switch, and provide a latch type tightening tool that is reliable and has a long life.

The present invention releases the pressing force of the tightening force adjustment spring in conjunction with the disengagement of the clutch, turns on the stop signal generation switch,
After the clutch is disengaged, the relationship between the clutch, the tightening force adjustment spring, the stop signal generation switch, and the return spring is designed so that the clutch is disconnected by the return spring with a sufficiently small pressing force compared to the pressing force of the tightening force adjustment spring. It was devised.

An embodiment of the present invention is shown in FIGS. 1 to 4 below.

In FIGS. 1 to 3, 1 is an electric motor, and 2 is a speed reduction device using a planetary gear mechanism. A fixed clutch 3 supports the planetary gear 2a of the speed reduction device 2. Two rollers 4 are provided protruding from the fixed clutch 3 to form a cam. 5
is a shaft, at one end of which a socket 7 for holding a driver bit 6 is connected and supported by a pin 8 and a set screw 9;
A movable clutch 12 consisting of a rotary plate 10 and a steel ball 11 is attached to the other end so as to rotate together with a key 13. The steel balls 11 are housed so as to be freely protrusive and retractable from both end faces of the rotary plate 109, and are pressed into engagement with the fixed clutch 3 through the sleeves 15, '17, and push pins 16 by the pressing force of the tightening force adjustment spring 14. ing. 18 is a gear cover that houses each component. Reference numeral 20 denotes a push button switch as a stop signal generating switch, which is held by a pin 19 on the gear cover 18 and is shut off via a shear actuator 22 by the pressing force of a return spring 21. (In this embodiment, the normally closed contact of the pushbutton switch is used, and the pushbutton 20
When a is pushed in, it becomes a shut-off state. ) The actuator 22 is disposed so as to be freely slidable on the sleeve 16 in the axial direction.

In FIG. 4, 25 indicates a DC power supply. 26 is electric motor 1
The starting switch 27 is a forward/reverse changeover switch that selects whether the motor should be rotated in the forward or reverse direction, that is, whether it should be tightened or loosened.

29 is an NPN transistor. When the start switch 26 is turned on, the base is energized by the resistor 28, so it becomes conductive and rotates the motor 1. 31 is a thyristor which resistor 30 when the push button switch 20 is turned on.
The gate of the thyristor 35 is energized through the resistor 33 and becomes conductive, thereby energizing the base of the NPN transistor 32 through the resistor 33 and 34, and the gate of the thyristor 35 through the resistor 36.

When the NPN) transistor 32 becomes conductive, the base and emitter of the NPN) transistor 29 are short-circuited and are cut off, so that the supply of τ power to the motor 1 is cut off.

On the other hand, the thyristor 35 conducts and short-circuits the motor 1 through the resistor 38, so that dynamic braking is applied to the motor 1 to immediately stop its rotation.

Next, the operation during tightening work will be explained. In the figure, when the start switch 26 is turned on and the electric motor 1 is rotated, the rotational force is transmitted to the fixed clutch 3 and the movable clutch 1 via the reduction gear 2.
2 and further transmitted to the key 13, shaft 5, socket 7
is transmitted to the driver bit 6 via the screw etc. (not shown)
Tighten.

As the screw continues to be tightened, the predetermined tightening progresses, and when the predetermined tightening force is reached, the steel ball 11 overcomes the pressing force of the tightening force adjustment spring 14 and is pushed toward the axial sleeve 17, causing the fixed clutch 3 and the movable clutch to be pushed out. 12 is in a disengaged state, transmission of rotational force is cut off. (See Fig. 3) On the other hand, the sleeve 17 with 11 steel balls is connected to the sleeve 15 via the push pin 16.
The actuator 22 is simultaneously pushed out in the axial direction, and the push button 20a of the push button switch 20 is opened to be in the closed state and a stop signal is generated. As a result, the rotation of the stain mower 1 is stopped and the screw tightening is completed. Furthermore, when the steel ball 11 crosses the cam surface formed by the rollers 4 of the fixed clutch 3, a tightening force of N8 k is applied to the sleeve 15 again due to the pressing force of the spring 14.
．． 17, and is pressed onto the fixed clutch 3 via a push pin 16. Thereafter, the push button switch 20 is shut off by the pressing force of the return spring 21 of the actuator 22, and the operation waits until the next tightening operation.

FIG. 5 shows a modified example of application of the present invention.

In the figure, the return spring 45 is held on the sleeve 15 by a 17-wheel 44. In this modified application example, after the clutch is disengaged, the restoring acceleration of the tightening force adjustment spring is applied to the actuator via the return spring 21, and the cutoff speed increases. However, if the suppressing force of the return spring 45 is appropriately selected. It functions effectively as a cushion when the actuator 22 is in operation, and can achieve substantially the same effects as the embodiments shown in FIGS. 1 to 4.

According to the present invention, as described above, the stop signal generating switch can be turned on and off regardless of the clutch disengagement speed or the magnitude of the pressing force of the tightening force adjustment spring, so that the pressing force of the return spring can be applied to the stop signal generating switch. It is possible to keep the closing and shutting speeds low by setting appropriate values.

Therefore, it is possible to provide a clutch-type tightening tool with high reliability and long life.

[Brief explanation of drawings]

Fig. 1 is a vertical sectional side view of a clutch-type tightening tool according to an embodiment of the present invention, Fig. 2 is a sectional view taken along the line I-I in Fig. 1, and Fig. 3 shows the clutch engagement in III. ? An explanatory diagram showing the released state, FIG. 4 is an electric circuit diagram. FIG. 5 is a longitudinal sectional side view of a clutch-type tightening tool showing a modified example of application of the present invention. In the figure, 23 is an adjustment ring that adjusts the pressing force of the tightening force adjustment spring, 24 is a top cover that connects and holds the adjustment ring 23, 37.39 is a resistor, 4
0.41 is a capacitor, 42 is a housing, and 43 is a metal. Patent applicant name Hitachi Koki Co., Ltd.

Claims (1)

[Claims] It has a dog clutch that is crimped and engaged with a clamping force adjustment spring that can freely adjust the pressing force, and the dog clutch disengages when a load greater than the pressing force of the clamping force adjustment spring is applied before tool installation. A stop signal generation switch is installed to detect clutch disengagement and operate, and the tightening tool uses the stop signal to cut off the power supply to the mode and completes tightening. An actuator that turns on and off the stop signal generation switch and a return spring that holds the actuator are provided in between, and the stop signal generation switch is turned on in conjunction with disengagement of the dog clutch, and after disengagement, the return spring again shuts off the stop signal generation switch. A clutch type tightening tool characterized by: