JPH05124564A - Bracket lug of bicycle frame - Google Patents

Abstract

PURPOSE:To enable formation of the respective pipes in widened toward-the-end shape by dividing a bracket lug whose connection parts to a vertical pipe, a lower pipe and a chain stay is formed integratedly into an upper and a lower part, and holding and welding the lower pipe and the chain stay by means of the upper and the lower lugs. CONSTITUTION:A bracket lug 4 whose connection parts 4a-4c to a lower pipe 1, a vertical pipe 2 and a chain stay 3 is divided into the upper and the lower parts by means of planes L1, L2 containing the center line of the lower pipe 1 and the center line of the chain stay 3 at the mounting position of the lower pipe and the mounting position of the chain stay, forming an upper molded lug 4A and a lower molded lug 4B. The vertical pipe 2 is inserted from the inside of this upper molded lug 4A, and at the same time, the lower pipe 1, the chain stay 3 and an inner cylinder for a bearing 5 are held to the upper molded lug 4A from the underside, then, the lower molded lug 4B is set over the upper molded lug to hold the lower pipe 1 and the chain stay 3 by means of the respective lugs 4A, 4B. A bracket lug is constituted by welding the respective connection parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a hanger lug portion of a bicycle frame.

[0002]

2. Description of the Related Art FIG. 4 shows a hanger portion of a bicycle. In the figure, 1 is a lower pipe of a bicycle frame, 2 is a standing pipe, 3 is a chain stay, 4 is a lower pipe 1, a standing pipe 2 and a chain stay 3. Hanger rug connected to each
Reference numeral 5 denotes a bearing inner cylinder fitted in the hanger lug 4, 6 denotes a crankshaft rotatably provided through the bearing inner cylinder 5, 7 denotes a crank arm, 8 denotes a crank pedal,
Reference numeral 9 is a crank gear, 10 is a chain, and 11 is a rear wheel.

FIG. 5 shows a state before assembly of a joint portion between a hanger lug of a conventional bicycle frame and each frame pipe, and the same reference numerals as those in the drawing denote the same parts. Reference numeral 4a is a connecting portion with the lower pipe 1, 4b is a connecting portion with the standing pipe 2, and 4c is a connecting portion with the chain stay 3.

[0004]

As shown in FIG. 4, the pedaling force applied to the pedal 8 of the bicycle acts as a moment on the hanger lug 4 through the crank arm 7 and the crankshaft 6, and as a result, the standing pipe 2 and the lower pipe. Large stress is applied to the vicinity of the connecting portion between 1 and the hanger lug 4. If this rigidity strength is insufficient, bending A due to the pedaling force occurs, and the transmission loss also increases.

In order to eliminate the above-mentioned inconvenience, the standing pipe 2 and the lower pipe 1 may be formed in a divergent tubular shape whose diameter gradually expands toward the connecting portion with the hanger lug 4, but the standing pipe 2 and When the lower pipe 1 is formed in a divergent tubular shape, as shown in FIG. 5, there is a problem that the lower pipe 1 and the vertical pipe 2 cannot be inserted from the outside of the connecting portions 4a and 4b of the hanger lug 4. there were.

[0006]

In order to solve the above-mentioned problems, in the present invention, a hanger lug integrally formed with a connecting portion of a standing pipe, a lower pipe and a chain stay is attached to a lower pipe mounting position and a chain stay mounting position. At the position, an upper mold lug and a lower mold lug are formed by vertically dividing each by a plane including the center line of the lower pipe and the center line of the chain stay, and the vertical pipe is inserted from the inside of the upper mold lug, and A hanger lug of a bicycle frame is formed by sandwiching and welding a pipe, a chain stay, and a bearing inner cylinder with the upper mold lug and the lower mold lug.

[0007]

As described above, in the present invention, since the hanger lug is divided into the upper mold lug and the lower mold lug, a vertical pipe formed in a divergent tubular shape can be inserted from the inside of the upper mold lug. Further, the lower pipe formed in a divergent tubular shape, together with the chain stay and the inner cylinder for the bearing, is sandwiched by the upper mold lug and the lower mold lug and welded, whereby the hanger lug portion of the bicycle frame can be integrally formed. ..

As described above, according to the present invention, it becomes possible to form the standing pipe and the lower pipe in a divergent tube shape, thereby increasing the rigidity of the hanger portion, so that the bending caused by the pedaling force of the crank pedal can be prevented. By suppressing, the transmission loss of the bicycle can be minimized.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the figure, the same reference numerals as those used above denote the same components. That is, in the figure, 1 is a lower pipe, 2 is a standing pipe, 3 is a chain stay, 4 is a hanger lug, 4a is a connecting part with the lower pipe 1, 4b is a connecting part with the standing pipe 2, 4c is a connecting part with the chain stay 3. Reference numeral 5 is an inner cylinder for the bearing.

In the present embodiment, the hanger lug 4 integrally formed with the connecting portions 4a, 4b and 4c of the lower pipe 1, the standing pipe 2 and the chain stay 3 is provided at the lower pipe mounting position and the chain stay mounting position. A plane L ₁ including the center line of the pipe 1 and the center line of the chain stay 3,
The upper mold lug 4A and the lower mold lug 4B are formed by dividing the upper mold lug 4A into upper and lower parts by L ₂ , respectively.
As shown in FIG. 2, the vertical pipe 2 is inserted, and the lower pipe 1, the chain stay 3, and the bearing inner cylinder 5 are attached to the upper mold lug 4.
After applying from below A, the lower mold lug 4B is covered from below as indicated by arrow B, the lower pipe 1 and the chain stay 3 are sandwiched between the upper mold lug 4A and the lower mold lug 4B, and the respective joints are welded. This constitutes the hanger lug of the bicycle frame.

FIG. 3 is a sectional view taken along the center line of the upright pipe 2, and according to the present invention, the lower end of the upright pipe 2 is expanded to form a divergent tubular shape. Pipe 2
Even if the diameter C of the lower end of the vertical pipe is larger than the diameter D of the upper end of the connecting portion 4b, that is, C> D, the standing pipe 2 is inserted from the inside of the upper mold lug 4A, so that the assembly is not hindered. Absent.

[0012]

As described above, in the present invention, since the hanger lug 4 is divided into the upper mold lug 4A and the lower mold lug 4B, even the vertical pipe 2 formed in a divergent tube is inserted from the inside of the upper mold lug 4A. can do. The lower pipe 1 formed in a divergent tubular shape is held together with the chain stay 3 and the bearing inner cylinder 5 by the upper mold lug 4A and the lower mold lug 4B and welded together to integrally form the hanger lug portion of the bicycle frame. Can be formed.

According to the present invention as described above, the vertical pipe 2
Also, the lower pipe 1 can be formed in a divergent tubular shape, which increases the rigidity of the hanger portion, thereby suppressing the bending caused by the pedaling force of the crank pedal and minimizing the transmission loss of the bicycle. The excellent effect of being able to do is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a hanger lug of a bicycle frame assembled according to the present invention.

FIG. 2 is a perspective view showing a state before the lower mold lug of FIG. 1 is joined.

FIG. 3 is a cross-sectional view showing a state in which FIG. 1 is taken along the center of a vertical pipe.

FIG. 4 is a perspective view showing a hanger portion of the bicycle.

FIG. 5 is a perspective view showing a state before assembly of a joint portion between a hanger lug and a frame pipe of a conventional bicycle frame.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower pipe 2 Vertical pipe 3 Chain stay 4 Hanger lug 4A Upper mold lug 4B Lower mold lug 4a, 4b, 4c Connection part L ₁ , L ₂ Plane including the center line 5 Inner cylinder for bearing 6 Crankshaft 7 Crank arm 8 Crank pedal 9 Crank gear 10 Chain 11 Rear wheel

Claims (1)

[Claims] 1. A hanger lug integrally formed with a connecting portion of a standing pipe, a lower pipe, and a chain stay, is provided with a plane including a center line of the lower pipe and a center line of the chain stay at a lower pipe mounting position and a chain stay mounting position. The upper mold lug and the lower mold lug are respectively divided into upper and lower parts, and a vertical pipe is inserted from the inside of the upper mold lug. A hanger lug for a bicycle frame, which is sandwiched and welded with a lug.