JPH0542261Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention can be used for adjusting the inclination of various devices such as word processors, personal computer display devices, seat headrest devices, reclining seats, etc. The present invention also relates to a shaft locking device applied to various types of lids, for example, to prevent toilet lids from falling.

[Prior Art] A shaft locking device is used, for example, to steplessly adjust the inclination angle of various devices such as those mentioned above. FIG. 4 shows a conventional example of this shaft locking device.
A movable bracket 31 that can be attached directly or indirectly to equipment (not shown) that requires tilt angle adjustment.
a fixed bracket 32 that is attached directly or indirectly to a support member (not shown) such as a base that supports the equipment; a fixed shaft 33 that is integrally attached to the fixed bracket 32; and the movable bracket 31. and a movable shaft 34 that rotates integrally with the movable shaft 34. The fixed shaft 33 is a stepped shaft, and a movable shaft 34 is rotatably inserted into the small diameter portion of the stepped shaft. In addition, the outer diameter of the large diameter portion of the fixed shaft 33 and the movable shaft 34
have the same outer diameter, and these fixed shafts 33
A coil spring 35 is fitted onto the movable shaft 34. The spring 35 is wound so that it has a diameter slightly smaller than the outer diameter of the shafts 33 and 34 in a free state, and when it is inserted onto the shafts 33 and 34, it is wound in close contact with these shafts. There is. In this case, both ends 35a and 35b of the spring 35 are free ends, and the end 35
It is inserted so that the end portion a is located on the movable shaft 34 side and the end portion 35b is located on the fixed shaft 33 side. In the shaft locking device having such a structure, the movable shaft 34 is moved by the frictional force of the spring 35.
is locked and the device is held at a predetermined angle. The angle adjustment is performed by applying an external force greater than this frictional force to cause a slip between the spring 35 and the movable shaft 34, and rotating the movable shaft 34. Rotation of this movable shaft 34 in the T _L direction (spring 3
5 rotation in the winding direction), locking torque is generated,
Rotation in the T _s direction (rotation in the unwinding direction of the spring 35)
In this case, slip torque is generated, but since the locking torque is larger than the slipping torque, the device is held at a constant angle using the locking torque.

[Problem to be solved by the invention] In such a shaft locking device, the rotating movable shaft 3
The winding of the spring 35 around the spring 4 is not uniform over the entire range. This is because the spring 35 is assembled to the movable shaft 34 with a predetermined tightening margin. This tendency is most noticeable at the end 35a of the spring 35 on the movable shaft 34 side, and as shown in FIG. As a reaction, the movable shaft 34 is not contacted on the side closer to the coil than the contact point P. In such an extrapolated state of the spring 35, the locking torque of the spring 35 cannot be kept constant, resulting in an unstable lock.

For this reason, the applicant previously proposed a shaft locking device capable of stabilizing the locking torque (Utility Application No. 63-28202). FIGS. 6 and 7 show examples of this shaft locking device. In the device shown in FIG. 6, a movable shaft 1 is rotatably fitted onto a fixed shaft 2, and a coil spring 3 is fitted onto these shafts 1 and 2. The fixed shaft 2 is a stepped shaft, and the movable shaft 1 is fitted onto the small diameter portion of the shaft. Spring 3
is extrapolated so as to span the large diameter portions of the movable shaft 1 and the fixed shaft 2.

In the free state, the spring 3 is connected to the movable shaft 1 and the fixed shaft 2.
It is wound so that the outer diameter is somewhat smaller than the outer diameter of the large diameter portion of the shaft, and after being fitted onto these, it comes into close contact with the movable shaft 1 and the fixed shaft 2. This locks the rotation of the movable shaft 1, and the equipment (not shown) to which the movable bracket is attached is locked at a predetermined angle of inclination. In such a shaft locking device, the end 3a of the spring 3 on the movable shaft 1 side extends in the tangential direction of the outer circumference of the movable shaft 1, as shown in FIG. That is, the end 3a of the spring 3
A portion 3b slightly closer to the coil contacts the outer circumferential surface of the movable shaft 1, and the end portion 3a extends in a tangential direction from this contact point 3b. As a result, the end 3a of the spring 3 on the movable shaft 1 side is separated from the outer circumferential surface of the movable shaft 1, and the end 3a does not come into contact with the outer circumferential surface of the movable shaft 1. Therefore, the other coil portions of the spring 3 except for the end portion 3a are uniformly brought into close contact with the outer circumferential surface of the movable shaft 1 regardless of the operation, so that a stable locking torque can be obtained.

On the other hand, in the apparatus shown in FIG. 7, a stepped shaft body consisting of a small diameter portion 1a and a large diameter portion 1b is used as the movable shaft 1. The large diameter portion 1b of the movable shaft 1 is formed to have the same outer diameter as the large diameter portion 2b of the fixed shaft 2, and the spring 3 is in close contact with the large diameter portion 1b. On the other hand, the spring 3 does not come into close contact with the small diameter portion 1a of the movable shaft 1, but the spring 3 is inserted so that the end 3a of the spring 3 is located in the small diameter portion 1a. Therefore, the end 3a of the spring 3 and the movable shaft 1
The other coil portions of the spring 3 are separated from the small diameter portion 1a of the movable shaft 1 without coming into contact with each other, and the other coil portions of the spring 3 are evenly and closely contacted with the large diameter portion 1b of the movable shaft 1, so that the locking torque of the spring 3 is stable.

However, in the shaft locking device shown in FIGS. 6 and 7, if rust forms between the spring and the movable shaft due to long-term use or use in a high temperature and humidity environment, this rust may cause As a result, the locking torque increases extremely, making it impossible to adjust the inclination with a predetermined force. This rust is less likely to occur in the areas where the movable shaft and the spring are in contact, but is more noticeable at the ends of the spring 3 where they are not in contact with each other, causing lock torque fluctuations.

The present invention provides an improved shaft locking system which has the advantages of the shaft locking system shown in FIGS. 6 and 7.

[Means for Solving the Problems] The present invention provides a device in which a spring is closely inserted between a fixed shaft and a movable shaft, in which there is a gap between the end of the spring on the movable shaft side and the movable shaft. This gap is characterized by having grease interposed within the gap.

[Function] In the above structure, the grease is prevented from rusting while maintaining the effect of stabilizing the locking torque.

[Embodiment] FIGS. 1 and 2 show an embodiment of the present invention. A fixed shaft 12 consisting of a small diameter portion 12a and a large diameter portion 12b, a movable shaft 11 rotatably inserted into the small diameter portion 12a of the fixed shaft 12, and these shafts 11, 12.
It is provided with a spring 13 extrapolated so as to be stretched across. The outer surface of the large diameter portion 12b of the fixed shaft 12 and the outer surface of the movable shaft 11 are formed to be on the same surface, and the spring 13 is wound so that the diameter thereof is somewhat smaller than these diameters in the free state. ing. Therefore, when the spring 13 is inserted onto the fixed shaft 12 and the movable shaft 1, the spring 13 comes into close contact with these shafts 11 and 12, and the rotation of the movable shaft 11 is locked. In such a device, the end 1 of the spring 13 on the movable shaft 11 side
3a is formed to have a larger diameter than the other coil parts. In the illustrated example, the end portion 13a is wound so that the coil diameter gradually increases toward the free end, and a gap G is formed between the large-diameter end portion 13a and the movable shaft 11. has been done. This gap G is filled with grease 14 for lubrication.

In such a structure, as in FIGS. 6 and 7, the end 13a of the spring 13 does not come into contact with the movable shaft 11, so a stable locking torque can be obtained, and the connection between the spring end 13a and the movable shaft 11 is Since the grease 14 interposed in the gap G prevents rusting, the locking torque does not fluctuate even in long-term use or in a humid environment.

FIG. 3 shows another embodiment of the invention. In this embodiment, the movable shaft 11 is formed with a tapered surface 11a. The tapered surface 11a is formed to gradually become smaller in diameter toward the end 13a of the spring 13, and a gap G is formed between the spring end 13a and the movable shaft 11 by forming the tapered surface 11a. It is becoming more and more common. And this spring end 13a
Grease 14 for lubrication is interposed in the gap G between the movable shaft 11 and the movable shaft 11 to prevent rust from forming.

[Effects of the invention] As explained above, the invention creates a gap between the end of the spring and the movable shaft to prevent contact between them, so that the distance between the other spring parts and the movable shaft is uniform. In addition to achieving a close contact, the interposition of grease in the gap prevents rust in the area, ensuring stable locking torque over a long period of time without being affected by the usage environment. can get.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of one embodiment of the present invention, FIG. 2 is a partial sectional view thereof, FIG. 3 is a partial sectional view of another embodiment, and FIGS. 4 a and b are partial sectional views of a conventional example. Its BB cross-sectional view, FIG. 5, shows the V in FIG. 4b.
FIG. 6 is a partial sectional view of an intermediate product of the present invention, and FIG. 7 is a partial sectional view of another intermediate product of the present invention. 1, 11... Movable axis, 2, 12, 33... Fixed axis, 3, 13, 35... Spring, 3a, 13a...
Spring end, G...Gap, 14...Grease.

Claims (1)

[Scope of utility model registration request] In a device in which a spring is closely inserted between a fixed shaft and a movable shaft, a gap is formed between the end of the spring on the movable shaft side and the movable shaft, and grease is interposed in this gap. A shaft locking device characterized by: