JPH031608Y2 - - Google Patents

Description

[Detailed explanation of the idea] [Industrial application field]

The present invention relates to a multi-stage telescopic tube, and more particularly to a multi-stage telescopic tube used in rod antennas for radio and television sets.

[Conventional technology]

In the multistage telescopic tube as described above, generally, a cylindrical inner tube and an outer tube are fitted concentrically to each other,
Two approximately semi-cylindrical plate spring members are interposed in the gap between the outer circumferential surface of the inner tube and the inner circumferential surface of the outer tube to elastically hold the outer tube and the outer tube in any desired expansion and contraction state. What has been done is known. This approximately semi-cylindrical leaf spring member has a radius of curvature larger than the inner radius of the outer tube, and when the inner tube is inserted into the outer tube, it elastically deforms both sides of the inner tube and moves inside the outer tube. By placing it along the circumferential surface, spring back is exerted there. By the way, since such a leaf spring member is manufactured by punching, so-called edges are formed on both sides that contact the inner surface of the outer tube, and when the above-mentioned spring bag acts, this can damage the inner circumferential surface of the outer tube. Therefore, it cannot withstand long-term use. Therefore, the applicant of the present invention proposed in Utility Model Application Publication No. 44366/1983 a substantially semi-cylindrical plate spring member which is configured to come into elastic contact with the inner circumferential surface of the outer tube at the portion where no edges occur. This has support parts that touch the outer circumferential surface of the inner tube formed at both ends, one of which is fixed to the inner tube, and a quadratic curved surface that extends outward from the outer circumferential surface of the inner tube in the longitudinal direction and the circumferential direction. It has a bulging portion formed therein, and is formed into a so-called tortoise shape during punching. The curvature of this bulge in the circumferential direction across the top of the Kamenoko shape is set to be smaller than the inner radius of the outer tube, and the elastic contact with the inner peripheral surface of the outer tube is made at the top of the Kamenoko shape. It will be done. Therefore, when moving the inner tube in and out of the outer tube,
There was an advantage that the edge of the leaf spring member did not hit the inner circumferential surface of the outer tube and would not damage the inner circumferential surface of the outer tube.

[Problem that the idea aims to solve]

By the way, when the above plate spring member is punched,
Since the bulging part is formed by plastic working, the amount of elastic deformation against the inner circumferential surface of the outer tube is smaller than that of conventional leaf spring members, and unless manufacturing accuracy is improved, the sliding force for expansion and contraction will vary. Also, since the contact with the inner circumferential surface of the outer tube is a relatively wide surface contact, unlike the conventional linear contact, it is difficult to remove dust mixed into the outer tube and fatigue scum from the injected grease. Biting at the contact area, internally,
There were problems such as changes in the delicate sliding force of the outer tube and shortened lifespan.

[Means to solve the problem]

This invention was made in view of the above circumstances,
A cylindrical inner tube and an outer tube are fitted concentrically to each other, and two approximately semi-cylindrical leaf spring members are interposed in the gap between the outer circumferential surface of the inner tube and the inner circumferential surface of the outer tube. The leaf spring member is provided with support portions in contact with the outer circumferential surface of the inner tube at both ends in the tube length direction, and a bulge portion that bulges outward in a quadratic curved surface in the tube length direction and circumferential direction. , the bulging portion is in elastic contact with the inner peripheral surface of the outer tube, and one of the supporting portions is fixed to the inner tube, wherein the bulging portion is in contact with the inner periphery of the outer tube in the circumferential direction. A slit window having a predetermined width is formed, which has a curved surface with a radius of curvature smaller than the surface, is located at the center in the width direction, and extends between the support parts.

[Effect]

With the above configuration, the multi-stage telescopic tube of the present invention can be configured such that when the leaf spring member is inserted into the outer tube together with the inner tube,
The bulging portion is elastically deformed, but at this time, the slit window portion curves inward and contacts the inner circumferential surface of the outer tube at the quadratic curved surface between the slit window portion and both side edges of the leaf spring member. The edges of the slit window do not damage the inner circumferential surface of the outer tube, and a sufficient amount of elastic deformation to the inner circumferential surface of the outer tube can be obtained. Even with normal manufacturing precision, a product with little variation in sliding force can be obtained, and it is free from dust. Even if fatigue scum from dirt or grease collects on the sliding contact area, it can be guided through the slit window to the back side of the bulging part during the sliding process, so the dust and scum can be removed between the inner circumferential surface of the outer tube and the inner surface of the outer tube. It can prevent jamming, maintain stable sliding force, and extend service life.

【Example】

Hereinafter, the present invention will be specifically described based on an embodiment shown in the drawings. In FIG. 1, reference numeral 1 indicates an inner tube constituting a multi-stage telescopic tube, and 2 an outer tube. In the gap between the outer tube 2 and the inner tube 1 fitted therein, a substantially semicylindrical plate spring member is provided. 3, 3 are interposed along the inner tube 1 so as to hold it from the left and right sides. In addition, the above outer tube 2
A lead-out hole 2a is formed at one end of the inner tube 1 by reducing its diameter by drawing. The reduced diameter portion surrounding the outlet hole 2a prevents the leaf spring members 3, 3 from slipping out of the outer tube 2. Similarly, one end of the inner tube 1 is also drawn, and an outlet hole 1c is formed therein, into which another telescopic tube (not shown) is inserted. As shown in FIGS. 3 to 5, the plate spring member 3 is formed by punching with a press, and has supporting portions 3a having the same curvature R in contact with the outer circumferential surface 1a of the inner tube 1 at both ends in the tube length direction. , 3a, and between these, a bulge portion 3c is formed outward in the pipe length direction and the circumferential direction as a quadratic curved surface, and the radius of curvature in the circumferential direction at least at the maximum portion of the bulge portion 3c is outward. The radius of curvature in the circumferential direction is set to be smaller than that of the inner circumferential surface of the tube 2 (in this embodiment, the radius of curvature in the circumferential direction is approximately equal to that of the support portion 3a at any part between the support portions 3a). ). In this way, the plate spring member 3 is held in a state in which the supporting parts 3a, 3a are in contact with the inner tube 1, and in a state in which the bulged part 3c is raised. Further, the leaf spring member 3 forms a slit window 3d of a predetermined width, which is located at the center in the width direction and extends between the support parts. In this embodiment, the slit window 3d is formed by punching between the parting lines 4, 4 between the bulging portion 3c and the support portion 3a. In addition, in the figure, the reference numeral 3b is an engagement protrusion formed protruding from one side of the support portion 3a toward the inner tube 1, and an eyelet hole 1b into which the engagement protrusion 3b is inserted.
are formed in the inner tube 1 so as to be diametrically opposed to each other. In the above configuration, the eyelet hole 1b of the inner tube 1
The engagement protrusion 3b of the leaf spring member 3 is fitted into the plate spring member 3, and the pair of leaf spring members 3, 3 are attached so that their longitudinal direction is along the length direction of the inner tube 1, and in this state, the inner tube 1 is removed. Insert into tube 2. In this case, when the bulging portion 3c of the leaf spring member 3 is pushed into the outer tube 2, the bulging portion 3c has sufficient elastic deformation to extend in the longitudinal direction of the tube while increasing the radius of curvature in the circumferential direction. transform. Therefore, even with normal manufacturing precision, a product with less variation in sliding force can be obtained.
At this time, the slit window 3d formed in the bulged portion 3c is deformed to reduce its width, so that the edge of the slit window 3d is separated from the inner circumferential surface of the outer tube 2. It will look like Figure 6. The bulging portion 3c is in surface contact with the inner circumferential surface of the outer tube 2 between the slit window 3d and both side edges. Therefore, when the inner tube 1 is expanded or contracted with respect to the outer tube 2, dust and fatigue residue of lubricating grease mixed in the gap between the two tubes are transferred to the bulge 3c of the leaf spring member 3 and the inside of the outer tube 2. Even if they enter between the peripheral surface 2b and the slit window 3d,
Since it is guided to the space formed between the leaf spring member 3 and the outer circumferential surface of the inner tube 1 through the
The sliding force does not become unstable and the lifespan against wear can be extended. Furthermore, by punching, both sides of the bulging portion 3c of the leaf spring member 3 and the slit window 3 are formed.
Since there is no risk that the edges formed on the side edges of d will come into contact with the outer tube 2, scratch damage caused by the edges will not occur at the sliding portion. Note that the curved surface shape of the bulging portion 3c formed in the leaf spring member 3 in this embodiment is not limited to this. For example, the curvature of the curved surface in the width direction of the leaf spring member 3 is The curvature may be smaller than that of the outer circumferential surface 1a. Furthermore, the amount of elastic deformation of the leaf spring member 3 can be adjusted by appropriately selecting the width dimension of the slit window 3d.

[Effect of the idea]

According to the present invention, as explained above, the leaf spring member has both end support portions in contact with the outer circumferential surface of the inner tube, and is fixed to the inner tube by one of the support portions, and also has a bulge formed on the leaf spring member. is a quadratic curved surface that bulges out from the outer circumferential surface of the inner tube in the lengthwise and circumferential directions of the inner tube, and the radius of curvature in the circumferential direction is set to be smaller than at least the inner circumferential surface of the outer tube; A slit window having a predetermined width is formed in the center portion in the width direction, so that when the inner tube is inserted into the outer tube, the bulge of the leaf spring member that contacts the inner peripheral surface of the outer tube extends in the longitudinal direction of the tube. Since the side edge of the slit window is elastically deformed so as to return to the inner tube side, a sufficient amount of elastic deformation can be ensured. Therefore, even with normal manufacturing precision,
A product with no variation in sliding force can be obtained. Also,
The bulging portion is in surface contact with the inner circumferential surface of the outer tube, and even if there are edges due to punching on both sides of the bulging portion and the side edges of the slit window, the inner circumferential surface of the outer tube is No more scratches on the surface.
Furthermore, due to the presence of the above-mentioned slit window, even if dirt mixed in between the inner and outer tubes or fatigue scum from grease applied as a lubricant enters between the bulge and the inner peripheral surface of the outer tube, these will be prevented. Since it is led out to the back side of the bulging part through the slit window, the sliding force when the inner and outer tubes expand and contract is stably obtained, and the wear life of the expandable tube is greatly improved. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a half-sectional view showing the main parts of a multi-stage telescopic tube according to an embodiment of the present invention, FIG. 2 is a perspective view showing how the leaf spring member is attached to the inner tube, and FIGS. 3 to 5 are plates. The plan view, longitudinal sectional view, front view, and FIG. 6 of the spring member are all sectional views of the main parts taken along the line indicated in FIG. 1. DESCRIPTION OF SYMBOLS 1... Inner tube, 1a... Outer circumferential surface, 1b... Eyelet hole, 1c... Support hole, 2... Outer tube, 2a... Support hole, 2b... Inner circumferential surface, 3... Leaf spring member, 3a...
...Supporting part, 3b...Engaging protrusion, 3c...Bulging part,
3d...Slit window, 3e...Side edge, 4...Parting line.

Claims (1)

[Scope of utility model registration request] A cylindrical inner tube and an outer tube are fitted concentrically to each other, and two approximately semi-cylindrical leaf spring members are interposed in the gap between the outer circumferential surface of the inner tube and the inner circumferential surface of the outer tube. The leaf spring member has support portions in contact with the outer circumferential surface of the inner tube at both ends in the tube length direction, and a bulge portion that bulges outward in a quadratic curved surface in the tube length direction and circumferential direction between them. wherein the bulging portion is in elastic contact with the inner circumferential surface of the outer tube, and one of the supporting portions is fixed to the inner tube, wherein the bulging portion is in elastic contact with the inner circumferential surface of the outer tube in the circumferential direction. 1. A multi-stage telescopic tube, characterized in that it has a curved surface with a smaller radius of curvature, and is formed with a slit window of a predetermined width located at the center in the width direction and extending between the support parts.