JPH06227473A - Automatically extensible and contractible crank for bicycle - Google Patents

Abstract

PURPOSE:To take out the stronger applied force supplied to a chain ring by manpower equal to that in the conventional, by generating the longest length of a crank when it is nearly horizontal in the advance direction of a bicycle. CONSTITUTION:A crank 1 consists of the combination of a cylinder crank 2 and a piston crank 3, and a sun gear 6 is fixed on a hanger shell 5 form the outer periphery through a BB 4, and an arm 8 is fixed on a planetary gear 7 installed on the cylinder crank 2, and a pin A9 is installed at the top edge part, and a rod 11 is laid between a pin B10 installed on the piston crank 3, and a cylindrical roller receiving plate 13 is installed on the cylinder crank 2, and a cylindrical roller A14 is fed. A cylindrical roller receiving part 15 is formed on the piston crank 3, and a cylindrical roller B16 is feeding-installed, and the planetary gear 7 is meshed with the sun gear 6, and the cylinder crank 2 is fitted with the BB 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic telescopic crank for a bicycle, which comprises a combination of a cylinder crank and a piston crank, and has a planetary gear meshing with a sun gear and a cylindrical roller.

[0002]

2. Description of the Related Art A conventional bicycle crank has a fixed length and is fitted to a bottom bracket (hereinafter abbreviated as BB), and is attached with a pedal and rotated.

[0003]

Since the conventional bicycle crank has a constant length, the pedal only makes a circular movement about BB. The crank boosts human power by leveraging the principle, B
Although the chain ring is rotated by applying B, the range of applying force is between the top of the circular movement of the pedal and the bottom of 180 degrees in the direction of travel of the bicycle, and in the meantime, the position is almost horizontal with BB. Despite being the most strongly applied, the crank length was always the same, which was irrational and problematic as a device powered by weak human power.

According to the present invention, the length of the crank automatically expands and contracts during one rotation of the crank, and becomes the longest at a substantially horizontal position in the advancing direction where the strongest human power is applied and the human power is the same as the conventional one. Therefore, the purpose is to bring out stronger force.

[0005]

In order to achieve the above object, in the automatic telescopic crank for a bicycle according to the present invention, the crank is composed of a cylinder crank and a piston crank.
It consists of a combination of books, and the sun gear is fixed to the hanger shell from the outer periphery by burying BB, and the planetary gear is rotatably attached to the cylinder crank at the position where it meshes with the sun gear at the same time as the sun gear. An arm is fixed and a pin A is provided at the tip, and a rod is inserted between the arm and the pin B provided on the piston crank, and each pin is rotatably connected.

Further, in order to reduce friction in sliding between the cylinder crank and the piston crank, when the crank is in a horizontal position in the traveling direction of the bicycle, a square bottom surface is formed below the inner tip of the cylinder crank. A cylindrical roller receiving tray is provided, and a cylindrical roller A having a diameter of several millimeters larger than the depth of the cylindrical roller receiving tray is inserted thereinto to allow the dislocation.

For the same purpose as described above, a cylindrical roller bearing is provided above the tip of the piston crank near the BB, and a cylindrical roller B having a diameter of several millimeters larger than the depth of the cylindrical roller bearing is rotatably installed.

When the crank is fitted on the BB,
The crank stretches the piston crank to the maximum at the position where the maximum force is required in the traveling direction of the bicycle, the other crank contracts the piston crank to the minimum in the opposite direction of 180 degrees, It is meshed with the sun gear of and fitted into BB.

[0009]

With the automatic telescopic crank of the bicycle constructed as described above, when the crank starts to rotate at the minimum extension when the crank is substantially horizontal in the reverse traveling direction of the bicycle, the BB serves as the base axis and the planetary gears are the sun gear and the roller gear. Since it rotates while making contact, the linear distance between BB and the pin A fixed to the planetary gear gradually increases, reaching the maximum distance at a position of 180 degrees from the start position, and the linear distance again after 180 degrees. The same applies to the piston crank that connects the pin A and the pin B with a rod, and the pedal at the tip of the piston crank draws a trajectory of an irregular ellipse in which the direction of travel of the bicycle is greatly swollen. When the force is added by, it works to draw out stronger force with the same human power as before.

The movement of the cylindrical roller A is such that when the crank is at the vertical apex of the circular orbit in which the force begins to be applied, the cylinder crank and the piston crank have a slight V shape, and the cylindrical roller A moves toward the BB of the cylindrical roller tray. When the crank rotates, the piston crank is placed and it rolls in the pedal direction, and the crank turns 90 degrees from the start, but in the opposite direction it rolls in the BB direction, causing friction in the sliding of the cylinder crank and piston crank. In addition, the cylinder crank and piston crank have a slightly inverted shape when the crank is rotated backward from the vertical bottom point of 180 degrees from the start, and the cylindrical roller A is in the pedal direction of the cylindrical roller tray. Assists rolling and contraction of the piston crank, and between the 270 degree position and the vertical apex, pedal direction and BB direction The Although swings, the start through the normal vertex Loading crank also becomes faint meat shaped, cylindrical roller A is returned to the original motion.

Further, the cylindrical roller B is a piston crank B.
It is put into a cylindrical roller receiver near B and is freely rotatable. It is at a position on a variable diagonal line with cylindrical roller A, and serves to reduce sliding friction of the piston crank in the cylinder crank.

[0012]

EXAMPLES Examples will be described with reference to the drawings.
1 and 2, the left and right cranks 1 are paired
The sun gear 6 having a drum-shaped support is hidden in the BB 4 and fitted on the hanger shell 5 from the outer periphery and fixed by the screw 17. Crank 1 is cylinder crank 2 and piston crank 3
The cylinder crank 2 has BB at the end.
4, a planetary gear 7 having the same diameter as the sun gear 6 is rotatably mounted at a position closer to BB4 at a position closer to the sun gear 6, and a pin A9 is provided at the tip of the planetary gear 7. The fixed arm 8 is fixed. When inserting the piston crank 3 having the hole for mounting the pedal at the end into the cylinder crank 2, as shown in FIG. 3, the cylindrical roller A is put into the cylindrical roller tray 13 and the cylindrical roller receiver 15 of the piston crank 3 is inserted into the cylindrical roller receiver 15. Install B16. Insert the piston crank 3 into the cylinder crank 2 and attach the captive screw 20 to the piston crank 3. Pin B10 to pinhole 1
8 and is inserted through the pin groove 19 so as to project and fixed to the piston crank 3, and the pin A provided at the tip of the arm 8
The rod 11 is passed between 9 and 9, and each pin is rotatably connected with a pin.

In the embodiment shown in FIGS. 1 and 2, when the crank 1 is fitted on the BB 4 and the sun gear 6, the crank 1 is located at a position where a maximum force is required in the traveling direction of the bicycle. 3 is stretched to the maximum, and the other crank 1 is the piston crank 3 in the opposite direction of 180 degrees.
Shrink to a minimum.

[0014]

Since the present invention is constructed as described above, it has the following effects.

When the planetary gear attached to the cylinder crank rotates around the sun gear together with the crank around BB of the basic shaft, the pin A at the outer peripheral position of the planetary gear has a linear distance from BB. According to this, the piston crank in which the length of the crank is short and the pin A and the pin B are connected by a rod also has a short length. Since the crank is set to be the longest at a substantially horizontal position in the traveling direction of the bicycle, it is possible to draw out a stronger force with the same human power as in the conventional art by the lever principle.

Further, although the cylindrical roller A has a simple structure, it is suitable for use in the cylindrical roller tray by changing the combination of the cylinder crank and the piston crank, moving the fulcrum, and automatically moving by gravity while the crank makes one revolution. The setting is done,
It is possible to reduce friction when the piston crank expands and contracts.

Further, the cylindrical roller B is located at a position on the variable diagonal with the cylindrical roller A in the cylinder crank, so that the piston crank can smoothly extend and contract.

Further, the circumference distance of the irregular ellipse drawn by the pedal is longer within 180 degrees in the traveling direction of the bicycle to which it is applied than within 180 degrees behind the non-application range, which leads to effective utilization of weighted human power. .

The automatic telescopic crank for a bicycle, which is composed of a combination of a small number of parts, can be used in a conventional bicycle, and because of its simple structure, the cost is low and the bicycle can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a side view of an automatic telescopic crank of a bicycle.

FIG. 2 is a plan view of an automatic telescopic crank for a bicycle.

FIG. 3 is a vertical sectional view taken along the line AA of the automatic telescopic crank of the bicycle.

[Explanation of symbols]

 1 Crank 2 Cylinder Crank 3 Piston Crank 6 Sun Gear 7 Planetary Gear 8 Arm 9 Pin A 10 Pin B 11 Rod 13 Cylindrical Roller Plate 14 Cylindrical Roller A 15 Cylindrical Roller B 16 Cylindrical Roller B 19 Pin Groove

Claims (2)

[Claims] 1. The crank (1) is composed of a combination of two cylinder cranks (2) and piston cranks (3), and the sun gear (6) is hidden in the bottom bracket (4) from the outer periphery to the hanger shell (5). ) Is fixed, and the planetary gear (7) is rotatably attached to the cylinder crank (2) at a position where the planetary gear (7) meshes with the sun gear (6) and meshes with the sun gear (6). ) Is fixed and a pin A (9) is provided at the tip end, and a rod (11) is inserted between the pin A (9) provided on the piston crank (3) and rotatably connected with each pin. Automatic telescopic crank for bicycles. 2. When the crank (1) is in a horizontal position in the traveling direction of the bicycle, a cylindrical roller tray (13) is provided below the inner tip of the cylinder crank (2) to allow the cylindrical roller A (14) to be displaceable. ) And then the piston crank (3)
The automatic telescopic crank for a bicycle according to claim 1, wherein a cylindrical roller bearing (15) is provided above a tip end portion of the bicycle near the bottom bracket (4), and the cylindrical roller B (16) is rotatably installed.