Human-powered driving mechanism

Abstract

A human powered drive units each including a pair of a rotatable member having a sprocket and a supporting member having a sprocket, which are arranged up and down, and including a chain extended around the rotatable member and the supporting member, are disposed at left and right sides, respectively. The left and right rotatable members 1, 100 are fixed on a driving shaft 15. A chain ring 6 on which the load is applied is mounted on the driving shaft between upper rotatable member 1 and rotatable member 100. In each of the units, constraining means including a free crank (10 for the right-hand unit, and 1000 for the left-hand unit) and arm (11 for the right-hand unit, and 1100 for the left-hand unit), is provided so as to maintain perpendicularity of a shaft of the pedal relative to the plane in which the chain moves. By the rider kicking the pedal along the closed orbit including a linear orbit portion, the force transmitted to the pedal from the foot of the rider is efficiently converted to a rotational force in a longer period of time, thus increasing the power input.

Description

[0001]This application is a National Stage under 35 U.S.C. § 371 of International Application No. PCT / JP99 / 05147, filed Sep. 21, 1999, published in Japanese (not English) as International Publication No. WO 00 / 17039 on Mar. 30, 2000, which claims the benefit of Japanese Patent Application Nos. 268476 / 1998, filed Sep. 22, 1998, and 266391 / 1999, filed Sep. 20, 1999.TECHNICAL FIELD[0002]The present invention primarily relates to a driving mechanism for a human-powered vehicle such as a bicycle, a wheelchair, a boat, or a human-powered airplane, or a human-powered machine comparable to a human-powered vehicle, for example, a muscle training machine.BACKGROUND ART[0003]The driving mechanism for a bicycle and the driving mechanism for a leisure recreational pedal boot are identical in principle. Both driving mechanisms comprise a rotational axle, two cranks, or the left and right cranks, and a pair of pedals. More specifically, the two cranks are rendered different in rotational phase by ...

AI Technical Summary

Benefits of technology

"The present invention provides a human powered drive mechanism for a vehicle that includes a rotatable member, a supporting member, an endless driving member extended around the rotatable member and the supporting member, and a human powered drive receiving portion mounted to the endless driving member. The invention also provides various methods for constraining the rotation of the drive receiving portion and for varying the inclination angle of the endless driving member. The technical effects of the invention include improved efficiency, reduced weight, and improved control and stability of the vehicle's movement."

Problems solved by technology

However, the driving mechanism for a human-powered vehicle has not changed at all in principle.

In principle, a speed changing mechanism does not improve energy conversion efficiency, regardless of its configuration.

However, reducing the speed increasing ratio below a certain level is meaningless.

That is, as the speed increasing ratio is reduced in order to keep the bicycle running, the rider must pedal faster to rotate the driving axle faster in reverse proportion to the decrease in the speed increasing ratio, which in turn causes the rider to reach his or her limit in physical capacity, and also increases the friction and / or vibrations for which the bearings and chain of the driving mechanism are responsible.

Eventually, it becomes impossible for the rider to keep the bicycle balanced to continue riding.

Thus, it is obvious that there is a limit in the improvement in slope climbing performance.

Actually, however, the ankle joints, knee joints, and hip joints, are limited in their ranges of movement, and therefore, the force applied to the pedal always acts downward in the virtually vertical direction regardless of rotational angle of the crank.

Thus, as far as a single rotational cycle of the crank is concerned, this structural arrangement for a human-powered vehicle driving mechanism has not increased power output in practical terms.

Thus, as far as the entirety of a single pedaling cycle is concerned, increase in power output cannot be expected even in the case of the structural arrangement disclosed in the cited patent.

As a result, the energy of the rider is consumed to stretch the crank which could not be stretched.

However, within the body of the rider, blood rapidly circulates, and chemical reactions rapidly occurs, while consuming the energy of the rider.

Thus, in terms of the entirety of each pedaling cycle, a significant amount of increase in output cannot be expected from the driving mechanism in accordance with any of the aforementioned inventions.

However, this invention also has a problem in that unless the pedaling motion is not synchronized with the free spring movement, increase in the output cannot be expected (if the pedal is stepped on before it fully returns, a sufficient distance is not available for pedal acceleration to have positive work even in the case of this invention, the initial pedal speed, or the pedal speed at the very moment the pedal begins to be stepped on, is considered to be 0 m / s), and therefore, a significant amount of increase in bicycle speed cannot be expected.

However, this method has also a problem in that if the aforementioned relationship in the rotational phase between the chain ring and crank is fixed, the usage of the bicycle is limited.

For example, a certain phase difference, which may be suitable for riding a long distance at a constant speed, may not be suitable for riding up a slope or riding at full speed.

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