JPH0436914B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement of a pipe assembly type bicycle frame.

(Prior Art) Conventional pipe assembly type bicycle frames have shapes as shown in a to u in FIG. 5. The frames shown in FIGS. 3 and 4 are
This is a conventional frame close to c or n in the figure. In the figure, 1 is a head pipe, 2 is a main pipe, 3 is a hanger pipe, 4 is a vertical pipe, 5 is a back hawk,
6 is the chain stay, 7 is the rear stop, 8 is the drive gear,
9 is a driven gear, and 10 is a chain.

(Problems to be Solved by the Invention) In the conventional frame shown in FIGS. 3 and 4, the driven gear 9 on the rear wheel side is provided inside the chain stay 6 and backhawk 5. When connecting the drive gear 8 and the driven gear 9, the chain 10 will be passed through the almost triangular interior formed by the back hawk 5, chain stay 6, and vertical pipe 4. In addition to having to be separated, the chain 10 must be passed through a complicated chain case to be described later, and then the chain 10 must be connected.Therefore, there were problems in that the work required skill and the efficiency of the assembly work was poor.

In addition, when installing a chain case with all case types, in order to prevent the chain stay 6 on the right side from interfering with the chain case, the structure of the chain case itself becomes complicated, which not only reduces productivity. This is one of the reasons for the weight increase.

Furthermore, by reducing the pitch of the roller chain 10, the diameters of the driving gear 8 and the driven gear 9 can be reduced, and their weight can be reduced. However, in this conventional bicycle frame, as described above, the chain 10 Since the roller chain 10 and the chain stay 6 intersect with each other, there is a risk that the two may come into contact with each other, and this poses a problem in that it is not possible to easily reduce the pitch of the roller chain 10 to make it smaller and lighter.

(Means for Solving the Problems) In order to solve the above-mentioned problems, in the present invention, the front part of the main pipe connected almost horizontally to the hanger pipe is bent diagonally forward and upward, and a stand which stands up diagonally rearward is formed. A pipe is joined to the hanger pipe, and the ends of the short sides corresponding to the back hawks of the two pipes bent in an approximately V shape are respectively joined to the upper part of the vertical pipe, and the long sides corresponding to the chain stays are made almost horizontal. Then, the middle part thereof is joined to both sides of the vertical pipe above the hanger pipe, and the upper part of the vertical pipe and the rear part of the back hawk and chain stay form a rear triangle, and the tip of the chain stay is connected to the main pipe. The front part of the chain stay, the rear part of the main pipe, and the lower part of the vertical pipe are connected to the middle part of the pipe to form a front triangle, and a rear pawl is provided below the rear part of the chain stay to form a bicycle. Configure the frame.

(Function) As described above, the present invention has the tips of the chain stays connected to both sides of the vertical pipe above the hanger pipe joined to the middle of the main pipe in front, so that
The front part of the chain stay, the main pipe, and the vertical pipe form a front triangle, and the upper part of the vertical pipe, the back hawk, and the rear part of the chain stay form a rear triangle. If the strength is given, V
The back hawk and chain stay, which are shaped like letters, are small and lightweight, yet can provide sufficient strength for the frame. Further, since the chain between the driving gear and the driven gear and its entire case do not intersect with the chain stay, the above-mentioned problem can be solved.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. In the figure, the same reference numerals as the above-mentioned reference numerals indicate equivalent parts.

In this embodiment, the front part of the main pipe 2, which is joined to the hanger pipe 3 almost horizontally, is bent diagonally forward and upward, and the vertical pipe 4, which stands up diagonally rearward, is joined to the hanger pipe 3, forming a roughly V-shape. The ends 5a of the short sides of the two bent pipes 11 corresponding to the back hawks 5 are respectively joined to the upper part of the vertical pipe 4, the long sides corresponding to the chain stays 6 are made almost horizontal, and the intermediate parts 6a are It is joined to both sides of the vertical pipe 4 above the hanger pipe 3, and the upper part of the vertical pipe 4, the back hawk 5, and the rear part of the chain stay 6 form a rear triangle, and the tip of the chain stay 6 is connected to the main pipe. The front part of the chain stay 6, the rear part of the main pipe 2, and the lower part of the vertical pipe 4 form a front triangle.
A rear pawl 7 is provided projecting below the rear part of the chain stay 6 to constitute a bicycle frame.

In the figure, 12 is a connecting member between the left and right backhawks 5, and 13 is a connecting member between the left and right chain stays 6. In addition, 14 in Figure 2 is the entire chain case, 15 is the crank arm, 16 is the saddle, and 17
is the front hawk.

As described above, the present invention has the tip part 6b of the chain stay 6 joined to both sides of the vertical pipe 4 above the hanger pipe 3 connected to the middle of the main pipe 2 in front, so that the front part of the chain stay 6 and the main pipe 2 and the vertical pipe 4 form a front triangle, and the upper part of the vertical pipe 4, the back hawk 5, and the rear part of the chain stay 6 form a rear triangle. Therefore, the strength required for the vertical pipe 4 and the main pipe 2 is Given this, the V-shaped backhawk 5 and chain stay 6 can sufficiently secure the necessary strength of the frame even though they are small and lightweight. Further, since the chain 10 between the driving gear 8 and the driven gear 9 (see FIG. 4) and its entire case 14 (see FIG. 2) do not intersect with the chain stay 6, all of the above-mentioned problems can be solved.

(Effects of the Invention) Since the present invention is as described above, the following effects can be obtained.

(a) Since the chain can be hung in an endless state without separating the chain, the chain hanging work becomes easier, and the structure of all cases of the chain can be simplified. Assembly work also becomes easier. Therefore, the efficiency of assembly work is significantly improved.

(b) Both the driving gear and driven gear can be downsized without changing the gear ratio, and the entire case can also be downsized accordingly, reducing the weight of the bicycle as a whole and significantly improving riding performance. can do.

(c) Even when traveling on rough terrain or when the chain is extended, there is no risk that the chain will come into contact with the chain stay, so it is possible to prevent smooth rotation and unpleasant noise.

(d) Since the rear wheel can be easily attached and detached, puncture repairs can be done quickly and easily.

(e) An endless toothed belt can be used instead of a chain.

(f) The frame of the present invention has a front triangle formed by the front part of the chain stay 6, the rear part of the main pipe 2, and the lower part of the vertical pipe 4, and the upper part of the vertical pipe 4, the back fork 5, and the rear part of the chain stay 6. Since the rear triangle is formed by
Although the chain stay 6 is small and lightweight, it can sufficiently secure the necessary strength of the frame. Therefore, according to the present invention, it is possible to obtain a frame that is simple in appearance and excellent in design.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a bicycle frame of the present invention;
Figure 2 is a partial side view of a bicycle assembled using the frame, Figure 3 is a schematic diagram showing an example of a conventional frame of this type, and Figure 4 shows the transmission mechanism attached to the frame. Perspective view, Figure 5 a-u
FIG. 1 is a schematic diagram showing various conventional frame shapes. 1...Head pipe, 2...Main pipe, 3
...hanger pipe, 4...standing pipe, 5...back hawk, 6...chain stay, 7...back Tsume,
11... A pipe bent into a V shape.

Claims (1)

[Claims] 1. The front part of the main pipe, which is connected almost horizontally to the hanger pipe, is bent diagonally forward and upward, and a standing pipe that rises diagonally backward is joined to the hanger pipe, creating a backhawk of two pipes bent in an almost V-shape. The ends of the corresponding short sides are joined to the upper part of the vertical pipe, the long sides corresponding to the chain stays are made almost horizontal, and the middle parts are joined to both sides of the vertical pipe above the hanger pipe. A rear triangle is formed by the upper part of the pipe, the back fork and the rear part of the chain stay, and the tips of the chain stay are respectively joined to the middle part of the main pipe, so that the front part of the chain stay, the rear part of the main pipe, and the vertical pipe are connected. A bicycle frame characterized in that a lower part of the chain stay forms a front triangle, and a rear pawl is provided to protrude below the rear part of the chain stay.