JPH0635891Y2 - Integrated front fork with reinforced sleeve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention relates to an integrated front fork material provided with a reinforcing sleeve.

BACKGROUND ART Integral front fork is a method in which a shoulder is provided at the center of one pipe material, and the pipe material is bent in the same direction on the same plane from both ends to form two sheaths, that is, legs.
The front fork of the bicycle is molded.

As a method of manufacturing such a front fork, "a hydraulic bulge forming method for a single material of the front fork" (Japanese Patent Publication No. 58-933) has been disclosed.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention provides a crownless integrated fork material having excellent strength of the shoulder portion of the fork.

Means for Solving the Problems A shoulder portion of a bicycle front fork is set at a predetermined central portion of a pipe material, and both ends of the shoulder portion are bent in the same direction on the same plane. 4, the cylindrical sleeve 2 is fitted, the solid elastic body 1 is closely inserted into the cylindrical sleeve, and bulge molding is performed.
2 is bulged and closely attached to the shoulder portion of the integrated front fork to form the reinforced sleeve 2a, which is an integrated front fork material provided with a reinforced sleeve.

Function The present invention provides the drum drums 6-1 and 6-2 by piercing the through hole at the center of the shoulder of the integrated front fork, fitting the cylindrical sleeve, and closely inserting the solid elastic body to form the bulge. Since the cylindrical sleeve and the reinforced sleeve 2a formed by bulging in the shoulder portion of the front fork material are placed in the through hole 4, the crownless fork material having excellent strength of the fork shoulder portion can be obtained.

EXAMPLE FIG. 1 shows the appearance of a shoulder portion of a front fork, and a cylindrical sleeve 2 which can be closely inserted into a hole 4 which penetrates the shoulder central portion.
However, there is a cylindrical elastic body 1 which is inserted into the sleeve 2 in close contact therewith, and this elastic body 1 is solid.

FIG. 2 shows a longitudinal section of an integrated front fork 3 in which the cylindrical sleeve 2 inserted into the central bore of the shoulder is shown only on its side wall, and the solid cylindrical elastic body 1 is installed in the sleeve 2. Is shown.

FIG. 3 shows that the solid cylindrical elastic body 1 is provided with a pressing tool 4a on the upper side, and a lowering device 5 is installed on the lower side to support the elastic body 1 and simultaneously push up the elastic body 1 upward.

As a concrete machine for the pressing tool 4a and the lifting tool 5 shown in FIG. 3, known mechanical devices can be used.

In the bicycle parts manufacturing industry, it is well known that the hanger / lug supporting the bicycle pedal is produced by a method in which an elastic body is inserted into a pipe material and a pressing force is applied to the elastic body to form the elastic body. The reinforced sleeve 2a having the drum drum 6 shown in FIG. 3 is obtained by the rubber bulge molding method from the sleeve which is the devised pipe material.

When the sleeve 2a having the required drum 6 is formed, the upper pressing tool 4a is separated from the elastic body 1 and simultaneously released from the lower supporting and lifting tool 5, so that the reinforced sleeve 2a becomes the front fork. Place in the shoulder through hole. Welding, soldering, brazing, etc. are used as the stationary method.

It is considered that there is some concern about the strength of the shoulder of the front fork material without a cast part called a crown on the shoulder, that is, the strength of the shoulder is somewhat unclear, and various strengthening methods against the crown have been proposed.

Although the material of the integrated front fork used in the present invention is not particularly mentioned, the reinforcing sleeve of the present invention is particularly useful when the integrated front fork material is molded from aluminum or aluminum alloy pipe material.

Effect of the Invention Aluminum metal pipes are being adopted in order to make the bicycle body light and beautiful, and the present invention is effective for strengthening the shoulder portion of the crownless fork material.

[Brief description of drawings]

FIG. 1 is an exploded view showing a positional relationship among a solid elastic body 1, a sleeve 2, and a shoulder central hole 4 of an integrated front fork 3, and FIG. 2 is a sleeve 2 installed in the hole and the inside thereof. It is sectional drawing which shows the solid elastic body 1 which can be combined, and FIG. 3 shows explanatory drawing which the sleeve 2 shapes the drum 6 with a solid elastic body. DESCRIPTION OF SYMBOLS 1 ... Solid elastic body, 2 ... Cylindrical sleeve 2a ... Reinforcement sleeve, 3 ... Integral front fork 4 ... Penetrating hole, 4a ... Upward pressing tool 5 ... Supporting and pushing up tool, 6 ... Drum

Claims (1)

[Scope of utility model registration request] 1. An integral front fork formed by setting a shoulder portion of a bicycle front fork at a predetermined central portion of a pipe and bending both ends of the shoulder portion in the same direction on the same plane. Is fitted to the cylindrical sleeve 2, the solid elastic body 1 is closely inserted into the cylindrical sleeve, and bulge molding is performed to bulge the drum drums 6-1 and 6-2 into the shoulder portion of the integrated front fork. An integrated front fork material provided with a reinforcing sleeve, which is characterized in that the reinforcing sleeve 2a is closely formed.