JP2000027886A - Torque limiting type rotary fastening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To limit the fastening torque to a desired magnitude and add a large torque without limitation in loosening by providing a locking pawl to be engaged with a ratchet and a pressing spring for pressing a terrace part to a frictional engagement surface within a spring housing part. SOLUTION: When a torque adding part 1A is rotated clockwise seen from the side, a locking pawl 4 is released from a ratchet 23, and idled to the ratchet, while a screw cylinder 2 is rotated only by the friction force between frictional engagement surfaces 13 and 21 and advanced along a screw shaft 5. Thus, the frictional force between both the frictional surfaces 13, 21 can be preliminarily regulated by a pressing spring 3. When the torque adding part 1A is rotated reversely (arrowed direction) with the intension of loosening, the locking pawl 4 is regularly engaged with the ratchet 23, and the screw cylinder 2 can be surely loosened without being slipped even if any large force is added thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque limiting type rotary tightening device, and more specifically, a tightening torque is limited to a substantially desired value at the time of tightening, and a torque is reduced at the time of reverse rotation to loosen the tightening state. The present invention relates to an unrestricted torque-limiting rotary tightening device.

[0002]

2. Description of the Related Art Although a torque limiting type rotary tightening device having a content similar to the purpose or the purpose of the description is not completely in the past, it is generally hollow cylindrical and has the same usability as a long nut. I haven't had anything before.

[0003]

For this reason, in the present invention, the shape of the nut is generally hollow cylindrical and has the same usability as a long nut, and the tightening torque can be limited to a desired value. Is aimed at developing a device that can apply a large torque without limitation.

[0004]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the solution according to the first aspect of the present invention has a generally hollow cylindrical shape having a torque applying portion at one end. A body having a spring housing portion and a locking claw portion coaxially formed in the hollow portion thereof; a frictional engagement surface formed on a step portion of the spring housing portion; An internal thread portion is coaxially mounted on the inside, and an internal thread portion is formed on the inner peripheral portion to be screwed to the screw shaft, and another frictional engagement surface is formed on the end surface of the outer peripheral step portion to face-to-face engage with the frictional engagement surface. And a ratchet formed at a position corresponding to the locking claw on the outer periphery of the screw cylinder, and rotatably attached to the main body to engage with the ratchet in the locking claw. A locking claw and the step portion within the spring storage portion A torque limiting rotary clamping device having a pressing spring for pressing the Kosugakarigo surface.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. Reference numeral 1 denotes a generally hollow cylindrical main body, one end of which is, for example, a hexagonal head-shaped torque applying portion 1A. A spring storage portion 11 is coaxially formed radially outwardly near the other end of the inner peripheral portion opposite to the torque applying portion 1A, and is located at a position axially separated from the spring storage portion 11 by a wall surface. A stop claw 12 is likewise drilled coaxially.

[0006] Torque applying part 1 in the axial direction of spring storage part 11
The ring-shaped end surface 13 near A is a friction engagement surface in which a ridge for friction engagement protrudes from a wall surface just like a friction engagement surface 21 described later with reference to FIG.

In the hollow portion of the main body 1, a generally cylindrical screw cylinder 2 is rotatably disposed coaxially. This screw cylinder 2
In the middle, a step portion 24 extends radially outward, and on the inner peripheral portion, a female screw portion 22 is formed which is screwed to the screw shaft 5 to which the device is to be mounted.

The end face of the step portion 24 facing the friction engagement surface 13 is a friction engagement surface 21 in which a ridge 21A is formed in a protruding manner. Further, a ratchet 23 is formed on an outer peripheral portion corresponding to the locking claw portion 12 of the main body 1 as clearly shown in FIG.

A coil-shaped pressing spring 3 is fitted in the spring housing 11 of the main body 1 so as to press the step portion 24 of the screw cylinder 2 against the frictional engagement surface 13 of the main body. As a result, the frictional engagement surface 13 of the main body 1 and the frictional engagement surface 21 of the screw cylinder 2 are pressed against each other. Naturally, the frictional resistance to the relative rotation of the two is proportional to the magnitude of the pressing force. Is increased or decreased.

In the locking claw portion 12, the locking claw 4 is rotatably mounted on the main body 1 side, for example, at approximately two equally circumferential positions, and is always in the direction of engagement with the ratchet 23 by the wire spring 41. Powered times. For this reason, as is obvious from FIG. 2, the locking claw 4 is engaged with the ratchet 23 and rotates the screw cylinder 2 in the same direction only when the torque applying section 1A is rotated in the direction of the arrow.

Next, the use of the apparatus of the present invention will be described. The present invention can be applied to a case where the screw shaft itself is broken when excessive tightening torque is applied, for example, when it is used as a stopper for preventing the object inserted into the screw shaft 5 from coming out.

It is sufficient to turn the torque applying portion 1A clockwise as viewed from the side in the same manner as tightening a normal nut. In this case, the locking claw 4 is disengaged from the ratchet 23 and idles with respect to the ratchet, and the screw cylinder 2 is rotated only by the frictional force between the friction engagement surfaces 13 and 21.
(To the right with respect to FIG. 1).

When the screw cylinder 2 hits the object and pushes it, and when this pushing force is too large than a desired set value, the frictional engagement surfaces 13 and 21 start slipping, and the object is pressed too much and broken. There is no fear. For this purpose, both friction surfaces 1
The frictional force between 3 and 21 may be adjusted to a predetermined value in advance. For this purpose, the spring force of the pressing spring 3 may be adjusted. Of course, if the spring force is increased, the frictional engagement force is increased, which is in a direct proportional relationship.

However, when the torque applying portion 1A of the apparatus is rotated in the reverse direction (the direction of the arrow in FIG. 2) for the purpose of loosening, the locking claw 4 always engages with the ratchet 23,
No matter how much force is applied, the screw cylinder 2 can be securely loosened without slipping.

[0015]

According to the present invention, the nut has the shape of a long axis, so that it can be used as easily as a nut, and when tightening, the tightening torque can be limited to a desired value. There is no danger of breaking, and when loosening, no matter how much force is applied, there is no risk that it will not come off even if the tightened part becomes old and rusted. Can be applied.

[Brief description of the drawings]

FIG. 1 is a simplified side sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line AA in FIG.

3 is an end view of the friction engagement surface 21. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 1A Torque addition part 11 Spring accommodating part 12 Locking claw part 13 Friction engagement surface 2 Screw cylinder 21 Friction engagement surface 21A Ridge 22 Female thread part 23 Ratchet 24 Terrace part 3 Press spring 4 Locking claw 41 Wire spring 5 Male screw shaft

Claims (1)

[Claims] A body (1) having a generally hollow cylindrical shape having one end serving as a torque applying portion (1A) and having a spring accommodating portion (11) and a locking claw portion (12) coaxially formed in the hollow portion. ), And a friction engagement surface (13) formed on a step portion of the spring storage portion (11), which is generally hollow cylindrical and attached coaxially to the inside of the main body (1). A female thread portion (22) is formed to be screwed to the male screw shaft (5), and another frictional engagement surface (21) that faces the frictional engagement surface (13) on the end surface of the outer step portion (24). ) Is formed, and a ratchet (2) formed at a position corresponding to the locking claw portion (12) on the outer periphery of the screw cylinder (2).
3), a locking claw (4) rotatably mounted on the main body (1) and engaging with the ratchet (23) in the locking claw (12); and the spring accommodating portion (11). A torque limiting rotary tightening device having a pressing spring (3) for pressing the step portion (24) against the friction engagement surface (13) within the parentheses.