JP2017206218A - Bicycle straight pedaling crank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bicycle drive device by straight pedaling that has a simple structure, lightweight and high reliability.SOLUTION: In a bicycle straight pedaling crank, a main crank (1) and a sub-crank (2) have the same length and are connected by a rotation shaft (7); a sprocket B (4) is attached to the sub-crank (2) by the rotation shaft (7); a sprocket A (3) having twice as many teeth as the sprocket B (4) is fixed to a hanger pipe (11) of a bicycle frame; and both sprockets are connected by a chain (5). In this mechanism, a pedal (15) reciprocates along a straight line that passes through a crankshaft.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a bicycle drive device that moves a foot up and down without rotating it.

Many pedals are used for pedaling, and rotating like a bicycle pedal seems to have a heavy burden on the structure of the human body. Since the invention of the crank / pedal mechanism, it has been a variety of straight pedaling for over 100 years. Attempts have been made. But none of them ended.
The primary cause was that it was too complex, too heavy, or lacked in reliability, not fit for the simplicity of a bicycle that only runs on human power.

  Special table 2009-531220 gazette

  The problem to be solved is the realization of straight pedaling suitable for bicycles, with a simple structure, light weight and high reliability.

The working principle of the present invention is shown in FIG.
There are a main crank (1) and a sub crank (2) of the same length connected by a rotating shaft. The main crank (1) is attached to the crank shaft, and the main crank (2) is attached to the sub crank (2) by the rotating shaft. 1) Set scissors B (4) with scissors. The sprocket A (3) having the same center as the crankshaft is fixed to the frame and does not move. The sprocket A (3) and sprocket B (4) have a gear ratio of 2: 1 and are connected by a chain.

  With the above configuration, when the main crank (1) is moved 45 degrees clockwise, the sub-crank (2) moves 90 degrees counterclockwise due to the difference in the number of teeth of the two sprockets. The pedal then moves on a straight line from P1 to P2.

When the main crank (1) is moved by 45 degrees, the sub crank (2) rotates in the opposite direction by 90 degrees, but the pedal is cranked to P1-P5-P1 due to the influence of the rotation of the main crank (1). Repeated reciprocating motion on a straight line passing through the axis.
In other words, if the sub crank (2) rotates twice while the main crank (1) rotates once, the pedal moves linearly. Even if it looks like the sub-crank (2) is moving and seems to have only made one rotation, the sub-crank (2) is actually making two rotations, and one rotation around the opposite of the main crank (1) has been subtracted. This is the result.

  When the pedal position is moved closer to the rotation axis by S, the pedal moves as Q1-Q5-Q1, and a long ellipse having a swell of S is drawn with respect to a straight line passing through the crankshaft.

FIG. 2 exemplifies the above-described operating principle. The main crank (1) and the sub-crank (2) have the same length, and the gear ratio between the sprocket A (3) and the sprocket B (4) is 2. Pair one.
With this configuration, the pedal reciprocates on a straight line passing through the crankshaft.
The above is the operation principle of the present invention, and the problem can be solved by realizing this as a bicycle drive device.

  Compared to rotational pedaling, the distance of the movement of the foot by straight pedaling is as short as two-thirds, and the improvement of the kinetic energy efficiency by simplification by simply stepping on the foot is great.

  Modern bicycles are used for short-distance driving (shopping bicycles), medium-distance (commuting / commuting bicycles), long-distance (sports cars), and racing. Aligned frame is designed. Unlike rotary pedaling, which requires complex movements at each leg, the adoption of a straight pedaling crank with simplified operation clarifies the riding posture suitable for each purpose, which is reflected in the frame design. Expects that bicycle users will be able to run more easily and develop more satisfying bicycles.

  It is explanatory drawing which showed the operating principle of the straight pedaling crank.   It is the perspective view which actualized the operation principle of the straight pedaling crank.   It is a perspective view of the Example of a straight pedaling crank unit.   It is sectional drawing of the right crank of a straight pedaling crank unit.

A unit that can be handled with conventional maintenance technology without losing the simplicity of a bicycle.
FIG. 3 is a perspective view of an embodiment of the present invention. In the main crank (1), a sprocket A (3), a sprocket B (4), and a chain (5) for connecting two sprockets are incorporated. A right crank with a ring attached and unitized is shown. The main crank of the left crank unit is transparent and shows the internal structure.

  FIG. 4 is a cross-sectional view of the right crank unit. In order to unitize, a sprocket A (3) is provided with a pipe-like support, and is fixed to the hanger pipe with a bottom bracket. Therefore, the right bottom bracket is also built in the crank unit before installation. Further, a bearing (13) is provided on the pipe-shaped support portion of the sprocket A (3), and the main crank (1) is supported at two locations including the crankshaft. The rotating shaft (7) that supports the sprocket B (4) is also supported and strengthened by two bearings (13) inside the main crank (1).

Since the unit-type crank can be handled in substantially the same manner as the conventional crank, the attachment process to the frame will be described.
The main difference between the straight pedaling and the crank is that the sub-crank (2), main crank (1) and crankshaft (6) on both sides are aligned in only one place. While the bicycle is running, the pedals on both sides reciprocate on the straight line. If the angle formed by the straight line and the horizontal line at that time is called the pedaling angle, setting the pedaling angle accurately is the first step in the mounting operation.

  The pedaling angle is not always vertical. Different pedaling angles and elliptical pedaling may be used if the purpose is different for short distance, medium distance, sports, and racing. For shopping bicycles, elliptical pedaling that can be used comfortably with the familiar rotating pedaling bicycle is preferred. Although it is an ellipse as a figure, the sense of stepping on the user is straight. In elliptical pedaling, the longer center line is a straight line that defines the pedaling angle. Since the pedaling angle suitable for the purpose of use is selected when designing the frame, it is necessary to accurately keep the determined pedaling angle even when the crank unit is attached. If it is not protected, the left and right pedals will move quickly and will not fully function as a straight pedaling bicycle.

  Since it is a unit type crank that can be easily attached, removed, and replaced, it is necessary to share the pedaling angle mounting information with the mounting frame, and the pedaling angle setting claw (16) plays the role. The frame-side hanger pipe (11) is also provided with a groove (16) in which the nail fits, and the function of setting an accurate pedaling angle is indispensable simply by inserting the nail into the groove during assembly work. This claw also prevents the crank unit that is stepped on with a strong force from rotating carelessly, and also prevents misalignment.

As the first step of installing the crank unit, put the unit into the crankshaft so that the sub crank (2), main crank (1), and crankshaft (6) are straight, and the pedaling angle setting claw (16) of the unit to the frame After fitting into the pedaling angle setting groove (16), the built-in bottom bracket (8) is screwed into the inserted bottom bracket unit (12), and the sprocket A (3) is firmly fixed to the hanger pipe (11). . Then, turn the sub crank (2) lightly and check that the chain in the unit moves smoothly.
Subsequently, the main crank (1) is coupled to the crankshaft (6). The crankshaft coupling cap (9) is pushed into the crankshaft with a strong force and fixed with a lock bolt (10) so as not to come off.
The left crank unit is also attached to the frame in the same manner, and the left and right pedals are screwed into the sub crank (2) to complete the attaching operation.

  The crank unit described so far is composed of two sprockets and a chain, but these can be replaced with a toothed belt, a toothed belt gear, or a general gear. The gear ratio of the gear fixed to the hanger pipe (11) and the gear attached to the sub crank (2) is made the same as 2: 1. In the case of a general gear, a gear unit having the same function can be obtained by adding a gear that transmits power in the middle. However, in order to maintain the rotation of the main crank (1) and the sub crank (2) in the opposite directions, the number of gears to be configured must be an odd number of 3 or more.

  A crank unit with a gear structure that is superior in durability without considering chain elongation is suitable for racing and travel bicycles that are assumed to be used severely.

  The straight pedaling / crank unitization will enable mass production at a bicycle parts company, which will lead to widespread use of straight pedaling bicycles by improving accuracy and function, diversifying types and optimizing prices.

1 Main crank 2 Sub crank 3 Sprocket A
4 Sprocket B
5 (Built-in main crank) Chain 6 Crankshaft 7 (Rotating two cranks) Rotating shaft 8 Bottom bracket 9 Crankshaft coupling cap 10 Lock bolt 11 Hanger pipe 12 Bottom bracket unit 13 Bearing 14 Chain ring 15 Pedal 16 Pedaling angle setting Nail, setting groove

Claims (4)

A double crank structure with two cranks connected by a rotating shaft that can be attached to a bicycle with a crankshaft.
A main crank attached to the crankshaft;
A sub-crank having a pedal mounting hole and coupled by the main crank and the rotating shaft;
Sprocket A fixed to the hanger pipe at the bottom of the frame;
A sprocket B having a half the number of teeth of the sprocket A, which is sandwiched between the main crank and attached to the sub crank by the rotating shaft;
Straight pedaling crank having a chain connecting the sprocket A and the sprocket B in a loop shape The distance between the pedal mounting hole of the sub-crank and the center of the rotating shaft is
The distance between the crankshaft of the main crank and the center of the rotating shaft,
If equal, the pedal attached to the sub-crank performs a linear reciprocating motion,
The straight pedaling crank according to claim 1, wherein the pedal movement changes from straight line to ellipse to ellipse as the length becomes shorter. The configuration of the sprocket A, the sprocket B and the chain is as follows:
Toothed belt and toothed belt gear,
It is possible to replace with an odd number of gears of 3 or more,
3. The straight pedaling crank according to claim 1, wherein the sprocket A and the sprocket B perform the same function by making the gear ratio of the gears replaced with the sprocket B equal to 2: 1 and the gear ratio of the sprocket. In a straight pedaling bicycle, there is only one angle between the straight line and the horizontal line when the sub-crank, main crank, and crankshaft on both sides are aligned.
To unitize straight pedaling cranks,
The angle information needs to be shared between the bicycle frame and the crank unit,
The crank unit and the unit having the structure and function according to claim 1, wherein a claw and a groove having information for setting a pedaling angle are provided on contact surfaces of the frame and the crank unit. Bicycle frame that can be attached.

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