FR2462331A1 - PEDAL - Google Patents

Abstract

A.PEDALIER. B. PEDAL BRACKET CHARACTERIZED IN THAT EACH ARM INCLUDES A CONNECTING MEANS CONNECTING ITS END TO THE PEDAL CRANKSHAFT, TO MODIFY THE LENGTH OF THE PEDAL ARM LEVER BETWEEN THE CRANKSHAFT SHAFT AROUND WHICH TURN THE ARM AND THE GEOMETRIC AXLE OF THE PEDAL CRANK.

Description

The present invention relates to a pedal bicycle with two arms

  integral in rotation with an axis carrying one or more toothed plates cooperating with a chain or transmission means acting on the driving wheel of the bicycle, the end of each pedal arm carrying a pedal, free to rotate about an axis parallel to the axis

of the pedalboard.

  On a crankset, the length of the lever arms,

  that is to say the distance separating the geometric axis from the man-

  The net of a pedal and the geometric axis around which the pedals turn corresponds to a length depending on the physical characteristics of the cyclist. The length of the arms

  Leverage currently used is an average.

  In general, it is difficult or impossible to

  sible to mathematically analyze the motor energy provided by the cyclist at each pedal stroke, that is to say during each pedal revolution. This study depends on the variation of the force exerted during a pedal revolution. Now, this strength

  depends on the physiological characteristics of the cyclist.

  However, and surprisingly, when the tests of bikes are made by different cyclists on identical and relatively long courses, there is a general trend that clearly emerges from the opinion of users (more or less rapid fatigue, difficulties ...) Starting from such large-scale trials, over a large population, the position could be determined

  ideal lever arm of the pedal.

  Contrary to what might seem obvious, it is not possible to increase the length of the lever arms to increase the torque that a cyclist can provide by exerting the same force as with a shorter lever arm. Indeed, it would result in a very important fatigue

  without, finally, the energy supplied being increased.

  Indeed, the power gain resulting from the increase of the lever arm results in a faster fatigue of the

  cyclist, since each foot travels a circular trajectory

  which is increased in the same proportion as the length

lever arms.

  For example, an increase in the length of the lever arms of only of the order of 10%, (which corresponds to a length of 15 to 20 mm), is not possible,

  without considerable increase in fatigue.

  The present invention aims to overcome these disadvantages and proposes to create a device to increase the energy provided by the cyclist without

increase his fatigue.

  To this end, the invention relates to a pedal characterized in that each arm comprises a connecting means connecting its end to the crank pin of the pedal, to change the length of the arm lever of the pedal between the pedal axis around which turns the arm and the geometric axis of the

crankpin pedal.

  According to an advantageous characteristic of

  tion, the connecting means is a parallel two-axis organ

  offset, one of the axes being rotatably mounted at the end

  mité pedal arm and the other axis constituting the crank pin of the pedal, these two axes being themselves parallel to the axis of the pedal, and in particular, the axis of the pedal is a disk mounted free to rotate in a unit corresponding to the end of each arm of the pedal, and bearing off-center, the second axis constituting the crankpin of the pedal. Thus, thanks to the invention, the torque is increased

  provided by the cyclist, without increasing the trajectories

  the foot of the cyclist.

  As stated above, the mathematical analysis of the work provided by the cyclist is virtually impossible to make. Nevertheless, secret tests carried out in the context of the present invention have shown that it is much less tiring to perform a certain cycling route (flat, slope length, steep slope) with a bicycle equipped with a pedal, according to the invention, compared to a conventional bike, or conversely that for the same fatigue you could move much faster with a bike

according to the invention.

  The gain in speed (or fatigue) represents in

  the experimental conditions defined above, an improvement

-ration of the order of 5 to 10%.

  It is particularly interesting to climb the axis

  pedal on a circular plate with possibly

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  a ball bearing, or with needles. This results in a very rigid structure, without increasing the frictional forces. A simpler device is to show, as indicated above, free rotation, one of the axes of the connecting means at the end of the pedal and connect

  by a connecting part to the axis receiving the pedal.

  The present invention will be described in more detail with the aid of the accompanying drawings, in which: - Figure 1 is a schematic side view of a pedal with two arms, according to the invention, - Figure 2 FIGS. 3 - 6 show a side view and a plan view of another embodiment of the invention, FIGS. 3 and 4 show the arm of FIG. pedal in the active position, - Figures 5 and 6 show the pedal arm in the inactive position, - Figure 7 shows an alternative embodiment

of the pedal of Figures 1 and 2.

  According to FIGS. 1 and 2, the crankset consists of two arms 1, 1 'integral with an axis 3 carrying the toothed plate or plates co-operating with the chain or more generally

  gears, etc ... depending on the transmission mode of the bike.

  The known parts do not require a description of

  detail. The arms 1, 1 'are for example fixed to the axis 2 by wedge-shaped wedges introduced into the

housing 3.

  The rest of the description will be mainly limited

  description of arm 1 and the organs that carry it

  since the arm i 'has identical members.

  For these identical organs, the references will be used

  arm 1, equipped with a "", without repeating the description.

  The front end 4 of the arm 1 carries, freely rotatable an axis 5, integral with an axis 6. The pins 5, 6 are parallel, but not coaxial. The axis 6 constitutes the crankpin

  carrying the pedal 7, possibly equipped with a footrest 8.

  To facilitate the description, especially of the operation of the

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  device, according to the invention, it is interesting to locate the geometric axes X-X, Y-Y, Z-Z respective axes 2, 5 and 6 which are parallel. The Y-Y axis is distant from the X-X axis of the distance R and the Y-Y axis is distant from the Z-Z axis of the distance a. Under these conditions, when the axes XX, YY and ZZ follow each other in this order, in the same plane (right part FIGS. 1, 2), the axis ZZ is distant from the distance (R + a) of the axis XX , whereas if the axes are in the same plane and follow each other in the order XX, ZZ, YY (left part, figures 1, 2), the distance between the axes ZZ and XX is equal to

(R - a).

  In the preferred embodiment of Figures 1 and 2, the stub axle 5 is, in fact, constituted by a disk mounted in a correspondingly shaped housing of the end of the crankset. Thus, each pedal arm has a tennis racket shape. To reduce the frictional forces between the disk 5a forming the axis 5 embryo and the housing 1a of the end of the arm 1, provision can be made for

  a ball bearing or better, a needle bearing.

  The manneton 6 of the pedal is carried by the disc 5a, so that the radius of the disc 5a is slightly

  greater than the distance to Y-Y - Z-Z axes.

  In this case, the connecting member 9, connecting the

  axes 5, 6, is constituted by the disc or the ring 5a.

  It is also interesting to replace the disk

  by a hollow disk or ring to lighten.

  Figures 3 to 6 show a second mode of

  which is simpler and less expensive than the first

  mier. Indeed, in this case, the connecting member 9 is in the form of arms carrying the two axes 5, 6. The stub axle 5 is projecting from one side of the member 9 and the manneton 6 is

  protruding from the other side of the organ 9.

  FIGS. 3 and 4 show respectively, from the side and in plan, a pedal in which the manneton 6 of the pedal 7 is at a distance (R + a) from the geometric axis

X-X rotation of the pedalboard.

  In contrast, Figures 5 and 6, which are respectively

  a side view and a view from above, the axis 6 of the pedal manneton is inside and is at a distance

  (R - a) of the axis X-X rotation of the pedal.

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  On the one hand, Figures 1, 2 and on the other hand, Figures 3, 4 represent the extreme positions that can occupy the axis 6 or the pedal 7 relative to the geometric axis X-X. When the cyclist alternately presses on the pedal (right or left) which at each pedal revolution is at the front in the direction of movement, the axis 6 tends

  naturally to come into the most forward position, that is,

  naturally say, the axis 6 and the pedal 7 occupy a position similar to that shown in Figures 1 and 2. Indeed, as the force exerted on the pedal 7 is directed downwards and forwards, according to the vector A (Figure 1), the angle formed between the arm 1 and the connecting portion 9 between the axes or mannetons 5, 6 tends to open and be close to 1800. Depending on the position of the assembly rotating on the path , this angle opens more or less, but remains

  always close to 1800 on the front half of the trajectory.

  By cons, in the return position or rear position, that is to say substantially on the rear half of the path of the pedal (part of the trajectory located substantially at the rear of a vertical passing through the axis geometric XX), as the foot of the cyclist does not exert any effort, but is recalled, by the movement of the other arm of the pedal that is in its active race, the connecting member formed by the axes 5, 6 and the connecting part 9 occupy a position similar to that shown in Figures 3 and 4, that is to say that the axis 6 or ZZ is between the axes

Geometric X-X and Y-Y.

  As a first approximation, the cyclist's foot occupies a constant position on its trajectory, so that the axis 6 describes a substantially circular trajectory that is deduced from the circular trajectory of the centered axis 5

  on the geometric axis X-X, following a translation correspon-

  at the distance from the Y-Y / Z-Z axes, according to the inclination

foot of the cyclist.

  As there is in practice, however, slight variations in the inclination of the foot, the trajectory is not

  perfectly circular. But these deviations are enough

  low to be negligible in most cases.

  In conclusion, the foot of the cyclist travels a circular path R of the same radius as the radius of the trajectory of the axis 5 around the geometric axis XX, which means that the movement of the foot is similar to that performed with a pedal known, but the lever arm varies significantly, since in the active part of the trajectory (front half of the trajectory), the length of the lever arm is greater than the length R and is equal, in the main part of the trajectory (R + a). In the passive part (back half of the trajectory) of the trajectory, the length is less than the length R and is close to the

length (R - a).

  FIG. 7 schematically shows a possible embodiment of an arm 1, in the form of a racket, lightened by a recess 1b and whose housing receives it a ring 5a provided with a housing 5b for receiving the crankpin

represented by the pedal 7.

  In practice the length "a" is of the order of

at 40 mm.

t

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Claims (1)

A crankset comprising two arms integral in rotation with an axle carrying one or more toothed platens cooperating with a chain or transmission means acting on the driving wheel of the bicycle, the end of each arm of the crankset. carrying a pedal, free to rotate about an axis parallel to the crank axle, crankset characterized in that each arm has a connecting means connecting its end to the crankpin of the pedal, to change the length of the lever of the arm of the pedal between the axis of the pedals around which turns the arm and the geometric axis of the crankpin of the pedal. 2) Crankset according to claim 1, characterized in that the connecting means is a member with two offset parallel axes, one of the axes being rotatably mounted at the end of the pedal arm and the another axis constituting the crank pin of the pedal, these two axes being themselves parallel to the axis of the pedal. ) Crankset according to claim 2, characterized in that the axis of the pedal is a disk mounted free to rotate in a housing corresponding to the end of each arm of the pedal, and carrying, off-center, the second axis constituting the crankpin of the pedal.   4) Crankset according to claim 3, characterized in that the disc is hollow and is in the form of a ring.    Crankset according to claim 2, characterized in that the two-axis offset linkage is a   piece constituted by two axes connected by a connecting member.