JPH06182672A - Electric thread fastener - Google Patents

Abstract

PURPOSE:To prevent the malfunction of the thread fastening depth adjusting mechanism of an electric thread fastener constituted of a thread hold section reciprocated in the thrust direction and a stopper restricting the retreat of the preset quantity or above of the thread hold section and capable of being moved in the thrust direction. CONSTITUTION:A spring 42 and a steel ball 41 are buried in the hole 40b of the side face of the stopper ring 40a of a stopper 40 adjusting the fastening depth, a stop plate 43 having a notch section 43a coupled with the steel ball 41 is hooked by a washer 44, the thread section of a coupling 30 is not scraped by the steel ball 41, and the malfunction of the stopper 40 due to the scraped powder is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric screw tightener having a stopper for adjusting the screw tightening depth.

[0002]

2. Description of the Related Art FIG. 3 shows the overall construction of an electric screw tightener according to the present invention. A screw holding portion 4 for holding a screw (not shown) to be tightened is slidably supported in a casing 5 and is pushed forward by a spring 6. A screw tightener main body 1 including a motor, a speed reducer, a clutch portion, and the like is provided with a bit 2 via a coupling 10 having a threaded outer periphery.
Is held and the screw is fastened to a gypsum board or the like (not shown) through the bit 2.

As the tightening of the screws progresses, the screw holding portion 4
Is retracted against the spring 6 and its rear end hits the stopper pin 8 when the tightening further progresses, and the stopper pin 8 hits the stopper 20 screwed into the coupling 10 at this point. The screw tightening is completed.

Therefore, the tightening depth of the screw can be adjusted by moving the stopper 20 forward and backward along the axial direction of the coupling 10. Reference numeral 3 is a screw tightening attachment composed of the screw holding portion 4, the casing 5, the spring 6, and the like, and 7 is a screw feeding member for feeding the screw held by a coupling band (not shown).

4 to 6 show the stopper 20 and the coupling 10. The stopper 20 includes a stopper ring 20a that is screw-fitted to the threaded portion 10a of the coupling 10, a steel ball 21 that engages with a groove 11 provided in the threaded portion 10a from an inner wall of the stopper ring 20a, and a steel ball 21. It is composed of an elastic body 22 made of, for example, an O-ring or the like pushed inward, a ring 20b fitted to the outer circumference of the stopper ring 20a, and the like. By rotating the stopper ring 20a via the ring 20b, the stopper 20 moves forward and backward in the axial direction.

[0006]

In the conventional tightening depth adjusting mechanism, when the stopper 20 is rotated, the steel ball 21 moves while sliding on the screw thread 10a of the coupling 10, so that the screw portion is 10a is scraped, and the scraped powder is accumulated in the steel ball hole of the stopper ring 20a, and the dust generated when the screw is tightened adheres to the screw portion 10a, so that the stopper ring 20a does not rotate smoothly. . An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and improve the reliability and operability of this type of electric screw tightener.

[0007]

The above-mentioned object is achieved by mounting a stop plate for suppressing rotation of the stopper on the side surface of the stopper ring via a spring and a steel ball.

[0008]

The tightening depth adjusting mechanism constructed as described above has a recess into which a steel ball is inserted to some extent by rotating a stopper ring by applying a certain load in the radial direction, and the main body of the electric screw tightener. The steel ball, which was fitted with the flat part of the coupling screw part with a certain gap, was locked by the spring bias in the recess of the plate that moves in the thrust direction, rides on the recess and rotates and moves in the radial direction together with the stopper. Rotation is suppressed at the next recess.

[0009]

The present invention will be described below with reference to the illustrated embodiments. FIG. 3 shows an embodiment of the essential parts of the electric screw tightener of the present invention. As shown in FIGS. 1 and 2, the stopper 40 according to the present invention includes a stopper ring 40a, a spring 42, a steel ball 41, a stop plate 43, and a washer 4.
4 and the like, a hole 40b having a specific depth is provided on the side surface of the stopper ring 40a, and the spring 4 is formed in the hole 40b.
2 and the steel ball 41 are inserted, and a stop plate 43 having a notch portion 43a at a position where the steel ball 41 is engaged is locked by a washer 44. It should be noted that the coupling 30 includes two flat portions 30.
a is provided, and the stop plate 43 is provided with a flat portion 40b corresponding to the flat portion 30a to prevent the stop plate 43 from rotating together with the stopper ring 40a.

When adjusting the tightening depth of the screw, the stopper ring 40a screwed to the outer peripheral thread portion of the coupling 10 is rotated against the urging force of the spring 42 acting on the stop plate 43. Steel ball 41 engaged with notch 43a of stop plate 43
Riding on the notch 43a and rotating together with the stopper ring 40a, the stopper 40 moves in the thrust direction. When the stopper ring 40a is further rotated, the steel ball 41 is engaged with the next cutout portion 43a of the stop plate 43 to prevent the stopper 40 from rotating.

[0011]

According to the present invention, since a steel ball or the like for suppressing the rotation of the stopper for adjusting the tightening depth of the screw is provided on the side surface of the stopper ring, the threaded portion of the coupling is scraped. , The disadvantage that the stopper does not rotate smoothly due to the scraped powder is eliminated. Also, by providing the steel ball on the rear side of the main body on the side opposite to the screw holding part, the dust generated during screw tightening is not directly applied between the steel ball and the stop plate, and the reliability and operability of the screw tightener are improved. Is greatly improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the essential parts of an electric screw tightener of the present invention.

FIG. 2 is an exploded perspective view showing a stopper and a coupling.

FIG. 3 is a sectional view showing an embodiment of the electric screw tightener of the present invention.

FIG. 4 is a perspective view showing a conventional screw tightening attachment.

5 is a cross-sectional view showing the stopper portion of FIG.

6 is an exploded perspective view showing the stopper of FIG.

[Explanation of symbols]

1 is an electric screw tightener, 2 is a bit, 4 is a screw holder, 5
Is a casing, 6 is a spring, 30 is a coupling, 30a
Is a flat surface portion, 40 is a stopper, 40a is a stopper ring,
40b is a hole, 41 is a steel ball, 42 is a spring, 43
Is a stop plate, 43a is a notch, and 24 is a washer.

Claims (2)

[Claims] 1. A screw holding part for holding a screw to be tightened and retreating as the tightening of the screw advances, and a screw part provided on the outer periphery of the main body is screw-fitted to a screw holding part having a predetermined amount or more. An electric screw tightening machine, comprising a stopper for preventing retreat, and adjusting the screw fastening depth by advancing and retracting the stopper along the outer circumference of the main body, wherein the stopper is screw-fitted on the outer circumference of the main body. Stopper ring, a steel ball inserted into a hole extending in the axial direction provided in the stopper ring, a spring for pushing the steel ball outward, and a stop plate having a notch with which the steel ball engages on the outer periphery, An electric screw tightening machine comprising a washer or the like that extends to a position that prevents the steel ball from falling off and pushes the stop plate toward the stopper ring. 2. The washer side of the stopper is provided on the rear side of the main body opposite to the screw holding portion.
The described electric screw tightener.