JPS6130537Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a locking device capable of preventing relative rotation between an outer pipe and an inner pipe inserted into the outer pipe.

As illustrated in FIG. 1, in a reclining seat 1 using a pipe, a headrest 2,
The backrest 3, seat part 4, footrest 5, etc. are connected via pivot parts 6, respectively, and each pivot part 6 has a lock mechanism (not shown) for setting a relative rotation angle. Each is provided. Conventional locking mechanisms of this type generally have a complicated structure, have a large number of parts, require a lot of labor to manufacture, and are expensive.

The present invention has been made in view of the above circumstances, and its object is to provide a locking device which is simple in structure, easy to manufacture, small and lightweight, and particularly suitable for pipe chairs and the like.

Hereinafter, the present invention will be explained based on an illustrated embodiment. In Figures 2 to 4, the outer pipe 1
0 has a hollow hole 11. In addition, the inner pipe 12
has an outer diameter smaller than the inner diameter of the outer pipe 10, and is rotatably inserted into the hollow hole 11. The inner pipe 12 has a threaded portion 1 provided at its outer end.
It has 3. A nut-shaped operating knob 15 is screwed into this threaded portion 13 via a washer 14 whose outer diameter is larger than the inner diameter of the outer pipe 10 .

Inside the outer pipe 10, the inner pipe 1
A cam member 17 is secured to the outer peripheral portion of 2 by a pin 16. The cam member 17 has a cylindrical portion 18;
A convex portion 19 is provided that extends in the axial direction continuously from the cylindrical portion 18 . The convex portion 19 is tapered with tapered cam portions 20 provided on both circumferential side edges.

A friction plate 21 is provided in the hollow hole 11 of the outer pipe 10 in a gap between it and the inner pipe 12 so as to be movable in the axial direction. The friction plate 21 has an axial sliding portion 22 and is formed to be expandable and retractable in the radial direction, and has a recess 2 located at the end facing the cam member 17 and communicating with the sliding portion 22.
It has 3. Cam followers 24, 24 are formed on both circumferential side walls of the recess 23 and are removably engaged with the cam portions 20, 20, respectively. In the illustrated example, the cam followers 24, 24 have a tapered shape with substantially the same slope as the cam portions 20, 20.

In the lock device configured as described above, when the operating knob 15 is screwed into the threaded portion 13,
Since the end surface of the operating knob 15 comes into contact with the end surface of the outer pipe 10 via the washer 14, the operating knob 15 is prevented from moving to the left (FIG. 2). Therefore, the inner pipe 12 is moved to the right (in the axial direction). Then, the cam member 17 is also moved to the right via the pin 16, so that the convex portion 19 is moved to the right side by the friction plate 2.
1, and the cam parts 20, 20 engage with the cam followers 24, 24. As a result, the friction plate 21 is pressed to the right, but the washer 14
Since movement to the right is prevented by the operating knob 15 via the cam followers 24, 24,
A force acts in a direction that separates them from each other with the sliding portion 22 as a boundary.

Since the friction plate 21 has a sliding portion 22 and is formed to be expandable and contractible in the diametrical direction, the diameter is increased by the above force and the outer peripheral surface of the friction plate 21 is pressed against the inner surface of the outer pipe 10. Therefore, the friction plate 21 and the outer pipe 10 are prevented from rotating relative to each other due to their frictional resistance, and the friction plate 21 is prevented from rotating relative to the cam followers 24, 24 and the cam portions 20, 2.
0 prevents relative displacement with the cam member 17, and since the cam member 17 is engaged with the inner pipe 12 via the pin 16, the outer pipe 10 and the inner pipe 12 are relative to each other. Rotation is prevented and the device is locked. Furthermore, if the operating knob 15 is rotated in the opposite direction to that described above, the pressing force of the friction plate 21 against the outer pipe 10 is reduced and the two can be relatively displaced, so that the outer pipe 10 and the inner pipe 12 are is in an unlocked state allowing relative rotation.

When applying the device configured as described above to a pipe chair, the outer pipe 10 and the inner pipe 1
For example, either one of 2 can be used as a seat frame,
By connecting the other to the backrest frame, a reclining seat can be constructed in which the inclination angle of the backrest can be adjusted steplessly.

Note that the present invention is not limited to the above-mentioned embodiment, and for example, as shown in FIG.
22. In this case, recesses 23 . . . that communicate with each of the sliding portions, and protrusions 19 that respectively oppose these recesses 23 . . . may be provided. All or part of the sliding portions 22 do not need to span the entire length of the friction plate 21. Further, the tapered cam portion 20 and the cam follower 24 may be provided only on one circumferential side of the convex portion 19 and the concave portion 23, and the cam follower 24 does not have to be tapered.

The locking device of the present invention consists of an outer pipe, an inner pipe that is rotatably inserted into the outer pipe and has a threaded portion at its outer end, and the inner pipe is screwed into the threaded portion to pivot the inner pipe relative to the outer pipe. an operating knob that can be moved in the axial direction; a cam member that is fixed to the outer periphery of the inner pipe inside the outer pipe; It is provided with a friction plate that is provided in a gap with the pipe and is expandable and retractable in the radial direction. The cam member is provided with a tapered cam portion that protrudes toward the friction plate, and when the cam portion enters the friction plate and is engaged with the cam portion, the friction plate is pushed apart to spread its outer peripheral surface. It is equipped with a cam follower that is brought into pressure contact with the inner surface of the outer pipe. Therefore, the cam member and the friction plate can be housed between the outer pipe and the inner pipe, resulting in a small and lightweight structure with a small number of parts. Since the structure is simple, it can be easily manufactured, and a locking device particularly suitable for pipe chairs and the like can be provided.

[Brief explanation of the drawing]

Fig. 1 is a schematic side view showing an example of a reclining seat, Fig. 2 is a sectional view showing an embodiment of the present invention, and Figs. 5 is a sectional view showing a modification of the friction plate. 10...outer pipe, 12...inner pipe, 13...
...Screw part, 15...Operation knob, 16...Pin,
17...Cam member, 20...Tapered cam portion, 2
1...Friction plate, 22...Sliding portion, 24...
Came follower.

Claims (1)

[Scope of utility model registration request] An outer pipe, an inner pipe that is rotatably inserted into the outer pipe and has a threaded portion at its outer end, and is threaded onto the threaded portion so that the inner pipe can be moved in the axial direction relative to the outer pipe. a cam member fixed to the outer periphery of the inner pipe inside the outer pipe, and a gap between the inner pipe and the outer pipe that faces the cam member in the axial direction and is movable in the axial direction. and a friction plate that is provided in the cam member and is extendable and retractable in the radial direction, and the cam member is provided with a tapered cam portion that protrudes toward the friction plate, and the cam portion fits into the friction plate and the cam A locking device characterized by being provided with a cam follower that pushes apart a friction plate when engaged with a cam follower and brings its outer circumferential surface into pressure contact with the inner surface of an outer pipe.