JP4516763B2 - Telescopic shaft for foldable umbrella - Google Patents

Description

  The present invention relates to an expandable and retractable multi-stage shaft used for a portable folding umbrella whose appearance does not show a slide guide.

In order to prevent free rotation of the pipes that make up the shaft, the retractable multi-stage shaft used in a conventional folding umbrella whose appearance does not show a sliding guide is used to prevent the inner diameter of each outer pipe. A ridge line is provided in the part, and a peripheral step and a groove are provided in the outer periphery of the inner pipe (see, for example, Patent Document 1).
JP 2001-353012 A (2 pages, FIG. 5)

A structure in which a protruding ridge line is provided on the inner side of the pipe and a peripheral step and a groove are provided on the outer periphery of the inner pipe requires high accuracy. If there is an error in the accuracy of the ridgeline, the sliding operation in the expansion / contraction direction of the shaft cannot be performed smoothly. For this reason, there is a problem that the manufacturing cost is increased because the accuracy of the manufacturing of the shaft is required.
An object of the present invention is to provide a shaft that can smoothly extend and contract without providing a protruding ridgeline over almost the entire length of a pipe.
Another object of the present invention is to provide a shaft having a round outer peripheral surface that looks good in appearance.

In order to achieve the above object, the present invention is a multistage telescopic shaft composed of a plurality of pipes used in a foldable western umbrella whose appearance does not show a sliding guide, and the plurality of pipes are nested. A slidably inserted and a concave groove is formed in the inner diameter portion of each of the plurality of pipes excluding the innermost pipe of the shaft along the longitudinal direction thereof along the longitudinal direction. A protrusion is provided on the outer diameter of the rear end of each pipe except for the outermost pipe of the shaft, and the protrusion of each pipe is axially inserted into a groove in the inner diameter of the outer pipe of each pipe. Is slidably fitted to the pipe to prevent relative rotation of the outer and inner pipes.
Moreover, this invention makes the cross-sectional shape of the said ditch | groove and the protruding item | line fitted to this circular arc shape.
In the present invention, a plurality of the concave grooves are provided at predetermined intervals in the circumferential direction of the pipe.
Moreover, this invention forms the outer peripheral surface visible from the outer side of each said pipe roundly.

  Since the present invention is configured as described above, the shaft can be expanded and contracted reliably and smoothly in a state in which the rotation of the inner pipe with respect to the outer pipe is prevented.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
Reference numeral 2 denotes a telescopic shaft for a folding western umbrella, which is configured in a multistage manner in which a plurality of pipes having different diameters and substantially the same length are slidably fitted in a telescopic manner. The second pipe 6 is slidably fitted to the inner diameter portion of the thickest first pipe 4, and the thinnest third pipe 8 is slidably fitted to the inner diameter portion of the second pipe 6. Yes.

  A skeletal component (not shown) and other parts for constituting a folding western umbrella are attached to the telescopic shaft 2 via a rocker (not shown). Each of the pipes 4 and 6 constituting the shaft 2 is made of a metal material such as aluminum, iron, brass or the like. As shown in FIG. 1 to FIG. 3, the inner diameter portions of the pipes 4 and 6 have three recesses parallel to each other in the longitudinal direction and at an interval of approximately 120 degrees from each other over the entire length in the longitudinal direction. Grooves 10 and 12 are formed. The cross-sectional shape of each of the concave grooves 10 and 12 is formed in an arc shape and has a smooth curved surface. The outer peripheral surface of the first pipe 4 is round over the entire length, that is, the outer cross section is formed in a circular shape.

  The outer peripheral surfaces of the second and third pipes 6 and 8 are formed with round portions K that are visible from the outside, except for the rear ends hidden by the outer pipes, and the pipes 6 and 8 correspond to each other. The outer pipes 4 and 6 are slidably fitted. As shown in FIG. 1 to FIG. 3, the pipes 6 and 8 are arranged in the direction parallel to the longitudinal direction of the pipes 4 and 6 on the rear end side of the outer peripheral surface of the pipes 6 and 8, that is, the base side of the pipes. Three ridges 14 and 16 having a predetermined length are projected from each other at an interval of approximately 120 degrees.

  The cross-sectional shape of each said protruding item | line 14 and 16 is comprised by the substantially same circular arc shape as the cross-sectional shape of the said concave groove 10 and 12. The dimension of the cross-sectional shape of the concave grooves 10 and 12 and the dimension of the cross-sectional shape of the corresponding ridges 14 and 16 are set to be substantially the same. 12 is configured so as to be slidably fitted. The pipes 4, 6 other than the third pipe 8 are squeezed at the tip to form a locking portion S. When the shaft 2 is extended, the pipes 4, 6 are connected to the locking portion S of the outer pipes 4, 6. The stoppers 18 fixed to the rear end portions 6 and 8 collide with each other so that the inner pipes 6 and 8 do not come off the outer pipes.

A pair of index holes 20 are formed in the vicinity of the tips of the outer pipes 4 and 6 with an interval of 180 degrees. In addition, a pair of through holes 22 are formed in the vicinity of the rear ends of the inner pipes 6 and 8 with an interval of 180 degrees. A spring (not shown) is bent at the rear ends of the inner diameter portions of the inner pipes 6 and 8, and protrusions (not shown) having convex curved surfaces are fixed to both ends thereof. The protrusion is fitted and disposed in the through-hole 22, and its tip convex curved surface is repelled in a direction protruding a predetermined amount from the through-hole 22.

  In the above-described configuration, the first pipe 4 and the second pipe 6 are slidably fitted into the groove 10 in the inner diameter portion of the first pipe 4 so that the ridges 14 of the second pipe 6 are slidable. The first pipe 4 and the second pipe 6 can be slid relative to each other only in the longitudinal direction, and the movement of the second pipe 6 relative to the first pipe 4 is prevented by the fitting structure of the ridges 14 and the grooves 10. The relationship between the second pipe 6 and the third pipe 8 is the same as the relationship between the first pipe 4 and the second pipe 6, and the sliding movement in the longitudinal direction of each other is possible. Is prevented by the outer pipe groove 12 and the inner pipe ridge 16 fitted thereto.

  When the shaft 2 is extended and the stoppers 18 of the inner pipes 6 and 8 are locked to the locking portions S of the outer pipes 4 and 6, the protrusions of the inner pipes 6 and 8 are just outside. The pipes 4 and 6 are fitted into the index holes 20, and the inner and outer pipes are locked so that the relative longitudinal movement and circumferential rotation can be released by a spring-biased protrusion. The pipes 6 and 8 are not easily detached from the corresponding outer pipes 4 and 6 and do not rotate.

The pipe used for the shaft which concerns on this invention is shown, (A) is a front view, (B) is a longitudinal cross-sectional view, (C) is an AA sectional view. It is an explanatory front view of the shaft concerning the present invention. It is a BB line sectional view of the shaft concerning the present invention.

Explanation of symbols

2 Shaft 4 Pipe 6 Pipe 8 Pipe 10 Concave groove 12 Concave groove 14 Convex strip 16 Convex strip 18 Stopper 20 Index hole 22 Through hole

Claims (3)

A multi-stage telescopic shaft composed of a plurality of pipes used in a foldable western umbrella whose outer appearance does not show a slide guide, wherein the plurality of pipes are slidably fitted in a nested manner, and the plurality of pipes A concave groove is formed in the inner diameter portion of each pipe excluding the innermost pipe of the shaft along the entire length thereof, and the outermost pipe of the shaft is excluded from the plurality of pipes. A protruding line is provided on the outer diameter part of the rear end of each pipe, and the protruding line of each pipe is slidably fitted in an axially slidable groove in the inner diameter part of the outer pipe of each pipe. A collapsible shaft for a foldable western umbrella characterized in that a relative rotation of an inner pipe is prevented , and a cross-sectional shape of the concave groove and a convex line fitted to the concave groove is an arc shape . 2. The collapsible shaft for a foldable umbrella according to claim 1, wherein a plurality of the concave grooves are provided at predetermined intervals in the circumferential direction of the pipe. 2. The collapsible shaft for a foldable umbrella according to claim 1, wherein a cross section of an outer peripheral surface visible from the outside of each pipe is circular .

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