JP2012157411A - Telescopic shaft for folding umbrella - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove backlash of joint parts in an extended state of a shaft used for a folding umbrella.SOLUTION: A telescopic shaft for folding an umbrella is a shaft in which a plurality of pipes are fitted and inserted slidably in a nesting shape with existence of predetermined clearance, each other, and can be extended and contracted. At the inner diameter parts of the respective pipes excluding the pipe on the innermost side of the shaft among the plurality of pipes, recessed grooves are formed over the entire length in a longitudinal direction. At the outer diameter parts of the rear parts of the respective pipes excluding the pipe on the outermost side of the shaft among the plurality of pipes, projecting lines are provided. The projecting lines of the pipes are fitted slidably in an axial direction to the recessed grooves at the inner diameter parts of the pipes on the outer side of the respective pipes, and the relative rotation of the pipes on the outer side and on the inner side is prevented. At the rear parts of the respective pipes excluding the pipe on the outermost side, a diameter expansion tube part is formed. On the outer peripheral surface of the diameter expansion tube part, the projecting lines are formed. The outer peripheral surface of the diameter expansion tube part is fit tightly to be slidable to the pipe on the outside.

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). The structure in which a protruding ridge line is provided on the inner side of the pipe and the peripheral step and the groove are provided on the outer periphery of the inner pipe has a problem in that the appearance of the pipe deteriorates because the groove appears on the surface of the pipe. In addition, a structure in which a protruding ridge line is formed over the entire length inside the pipe is required to have high accuracy and is expensive.
Therefore, the applicant has developed a retractable shaft for a umbrella that solves the above problems by providing a concave groove instead of a protruding ridge line on the inside of the pipe and preventing the groove from being seen on the surface of the pipe. (See Patent Document 2).

JP 2001-353012 A Japanese Patent No. 4516763

The telescopic shaft composed of a plurality of nested pipes of Patent Document 2 is provided with a locking portion by squeezing the tip of the outer pipe in order to prevent the pipe from being pulled out during extension. A stopper projection provided on the inner pipe is brought into contact. If a stop throttle is formed on the outer pipe, the diameter of the opening of the throttle is smaller than the inner diameter of the pipe, so the outer diameter of the inner pipe that is inserted into the outer pipe via the throttle Naturally, the diameter of the pipe is considerably smaller than the inner diameter of the outer pipe, and inevitably a considerably large clearance is formed between the two pipes. Because of this clearance, the pipes cannot be fitted closely together, and when the shaft is extended, there is a problem that the joint portion of the shaft is loose and the joint portion is blurred.
The present invention aims to solve the above problems.

  In order to achieve the above object, the present invention provides a telescopic shaft in which a plurality of pipes are slidably fitted in a slidable manner with a predetermined clearance between each other. A concave groove formed over the entire length along the longitudinal direction in the inner diameter portion of each pipe excluding the innermost pipe, and the rear of each of the plurality of pipes excluding the outermost pipe of the shaft Provided on the outer diameter portion of the portion, and a ridge that slidably fits in a groove in the inner diameter portion of the outer pipe of each pipe in an axial direction, and a rear portion of each pipe excluding the outermost pipe The formed expanded pipe portion extending in the axial direction of each pipe and having an outer diameter larger than the outer diameter of each pipe, and the tip end of each pipe excluding the innermost pipe Locking part formed by narrowing the part A stopper surface provided at a position for engaging the engaging portion with the enlarged diameter pipe portion, and forming the ridges on the outer circumferential surface of the enlarged diameter pipe portion, and the outer circumferential surface of the enlarged diameter pipe portion Is tightly slidably fitted to the outer pipe.

  Since the present invention is configured as described above, it is possible to remove the backlash of the shaft joint portion in a state where the telescopic shaft is extended, and to prevent the shaft from becoming uneven.

It is a section explanatory view of the shaft concerning the present invention. It is a front view of the pipe used for the shaft which concerns on this invention. It is AA sectional view taken on the line of a pipe. It is explanatory front view of a shaft. FIG. 3 is a sectional view taken along line B-B in FIG. 2.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 4 is an explanatory front view of a telescopic shaft 2 for a foldable umbrella according to the present invention. The shaft 2 is configured to slidably fit a plurality of pipes having different diameters and substantially the same length in a telescopic manner. It is configured in a multistage 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.

The telescopic shaft 2 is attached via a skeleton component (not shown) for constituting a foldable western umbrella. The pipes 4, 6, and 8 constituting the shaft 2 are made of stainless steel, aluminum, iron, brass, or other metal material. As shown in FIGS. 3 and 5, the inner diameter portions of the pipes 4 and 6 are parallel to each other along the longitudinal direction and have a length of about 120 degrees in the circumferential direction over the entire length in the longitudinal direction. Three concave 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 its entire length, that is, the outer cross-sectional shape is circular. The outer peripheral surfaces of the second and third pipes 6 and 8 are formed with rounded portions K that are visible from the outside, except for each rear portion of a predetermined length that is hidden by the outer pipe when the shaft 2 extends. The pipes 6 and 8 are slidably inserted into the corresponding outer pipes 6 and 8 with a predetermined clearance.

A clearance of about 0.2 mm is formed between the outer peripheral surface of the perfect circular portion K of the pipes 6 and 8 and the corresponding inner peripheral surface of the outer pipes 6 and 8. Outer pipes 4 and 6 other than the third pipe 8 are formed with locking portions S formed by narrowing the tips, and when the shaft 2 is extended, the inner pipes are connected to the locking portions S of the outer pipes 4 and 6. The stopper surfaces T formed on the rear portions 6 and 8 collide so that the inner pipes 6 and 8 do not come off the corresponding outer pipes 4 and 6, respectively.

Diameter expansion pipe portions 6a and 8a are formed in the rear portions of the inner pipes 6 and 8 over a length of about 2 cm. A step formed at the boundary between the expanded diameter pipe portions 6a, 8a and the perfect circular outer peripheral portion K forms a stopper surface T. The outer peripheral surfaces of the expanded diameter pipe portions 6a and 8a and the inner peripheral surface of the outer pipe are such that a smooth relative sliding movement in the axial direction between the expanded diameter pipe portions 6a and 8a and the outer pipe is possible. It has a slight clearance and is set to have substantially the same diameter.

The axial lengths of the expanded diameter pipe portions 6a and 8a are set to 2 cm in the present embodiment, but an optimum value is experimentally set so that the connecting portion of the shaft 2 does not get blurred when the shaft 2 is extended. Can be sought. As shown in FIGS. 3 and 5, three ridges 14 and 16 having a predetermined length arranged in parallel to the longitudinal direction of the pipes 4 and 6 are provided on the outer peripheral surfaces of the expanded diameter pipe portions 6a and 8a. Are spaced from each other at an interval of approximately 120 degrees in the circumferential direction and projecting over the entire length of the diameter-expanded tube portions 6a, 8a in the axial direction.

Each of the protrusions 14 and 16 has a cross-sectional shape that is substantially the same arc shape as the cross-sectional shape of the concave grooves 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, and each of the ridges 14 and 16 corresponds to the corresponding outer concave groove 10 and 16. 12 is configured to be slidably fitted. A pair of index holes 20 are formed in the vicinity of the ends of the outer pipes 4 and 6 at intervals of 180 degrees in the circumferential direction.

In addition, a pair of through holes 22 are formed in the pipe walls of the enlarged diameter pipe portions 6a and 8a of the inner pipes 6 and 8, respectively, with an interval of 180 degrees in the circumferential direction. A spring (not shown) is bent behind 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 stopper surface T of the inner pipes 6 and 8 is locked to the locking portions S (see FIG. 4) of the outer pipes 4 and 6, the inner pipes 6 and 8 are exactly the same. The projections of the outer pipes 4 and 6 fit into the index holes 20 of the outer pipes 4 and 6, and the relative longitudinal movement and circumferential rotation of the inner and outer pipes are released by the spring-biased projections. Locked so that the inner pipes 6, 8 do not easily disengage or rotate from the corresponding outer pipes 4, 6.

In this state, the outer peripheral surfaces of the expanded pipe portions 6a and 8a of the inner pipes 6 and 8 are fitted to the inner peripheral surfaces near the tips of the corresponding outer pipes 4 and 6 without any backlash. The shaft 2 is not glazed at the pipe joint, and the shaft 2 is firmly held in its extended state.

2 Shaft 4 Pipe 6 Pipe 6a Diameter expansion pipe part 8 Pipe 8a Diameter expansion pipe part 10 Concave groove 12 Concave groove 14 Convex line 16 Convex line 20 Index hole 22 Through hole

Claims (1)

A telescopic shaft in which a plurality of pipes are slidably fitted in a slidable manner with a predetermined clearance from each other, and an inner diameter of each of the plurality of pipes excluding an innermost pipe of the shaft A concave groove formed over substantially the entire length along the longitudinal direction of each of the plurality of pipes, and the outer diameter portion of each of the plurality of pipes excluding the outermost pipe of the shaft. A protruding strip that is slidably fitted in a groove in an inner diameter portion of an outer pipe of the pipe in an axial direction, and a rear portion of each pipe except for the outermost pipe. A diameter-expanded pipe portion extending and having an outer diameter larger than the outer diameter of each pipe; and a locking portion formed by constricting the tip to the tip of each pipe excluding the innermost pipe , Engage with the locking portion on the diameter expansion tube portion A stopper surface provided at a position where the protruding portion is formed on the outer peripheral surface of the expanded diameter pipe portion, and the outer peripheral surface of the expanded diameter tube portion is slidably closely fitted to an outer pipe. A retractable shaft for foldable western umbrellas.

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