WO1995026900A1

WO1995026900A1 - Ratio selection device for muscle-powered vehicles, particularly bicycles

Info

Publication number: WO1995026900A1
Application number: PCT/IB1995/000237
Authority: WO
Inventors: Willem Dieperink
Original assignee: Edco Engineering S.A.
Priority date: 1994-04-05
Filing date: 1995-04-05
Publication date: 1995-10-12

Abstract

A device comprising a front changer (5) and a rear changer (6), both of which are parallelogram-type changers. Said changers (5, 6) are electro-mechanically controlled for translation of the chain (36), and electronically power-assisted for the selection of an ideal ratio depending on the relevant parameters. For this purpose, the device comprises a data read-out unit and a computing unit, said units being arranged to maintain an ideal crankset rotation speed, and particularly to optimise the steps required to maintain a constant pre-programmed crankset rotation speed.

Description

Gear selection device for machines powered by muscular force, in particular for bicycles

The present invention relates to a gear selection device for gear driven by muscular force, in particular for a bicycle.

The optimal efficiency of the actuation of the pedal unit of a machine driven by muscular force is obtained for a certain number of revolutions P of pedals per minute, generally between 70 and 120 revolutions / minute. In the case of a bicycle, for each cyclist this cadence P is different, but it should preferably remain constant under all circumstances.

In order to allow the cyclist to maintain his optimal pace, current bicycles (city bikes, mountain bikes, racing bikes) are equipped with a pinion derailleur and often with a chain derailleur which can offer by their combination up to '' with 24 reports.

The well-known problem for every cyclist is to choose the right gear at all times, so that the cadence of the crankset allows him to make the most of the power he is able to deliver at all times.

Thus, assuming that the power developed by the cyclist is constant and that the cadence of the crankset is maintained at the optimal constant, the speed V (in km / h) of the bicycle varies according to the circumstances, in particular gradient, wind direction , road condition, etc.

In fact, the cyclist in full effort is left to himself and his feelings to make the choice of the report and to think of doing it. It often happens that a cyclist, failing to have started the report corresponding to his optimal pace, struggles with great energy and willpower to a return lower than that which it could ideally obtain for the same effort.

In order to free the cyclist from the constant concern of finding the right gear, automatic servo derailleurs have been proposed. These derailleurs are however based on a fully electronic servo acting on a linear chain guide system, in particular worm guide, which replaces the conventional parallelogram guide system. These devices often use low electrical voltages which make them easily disturbable, for example near high voltage lines. They are therefore unreliable. On the other hand, these derailleurs pose wear problems due to the linear guide of the chain.

The aim of the present invention is to propose a device for selecting ratios for machines driven by muscular force, in particular for bicycles, making it possible to remedy the drawbacks of known devices and in particular to maintain an optimal rate of rotation of the pedal of the bicycle. .

To this end, the invention relates to a gear selection device for machines powered by muscular force, in particular for a bicycle, comprising at least one crankset provided with at least one chainring and at least one derailleur as well as control means for the selection of the ratios, as defined in claim 1. The invention also relates to a derailleur as part of the device as defined in claim 9.

According to a preferred embodiment, the device comprises a front plate derailleur and a rear pinion derailleur, the two derailleurs being of the parallelogram type. These derailleurs are electro-mechanically controlled with regard to the chain translation. They are assisted electronically with regard to the management of the selection of the optimal ratio according to the parameters taken into account.

The device according to the invention makes it possible to automatically carry out the reading of the data allowing the optimization of the operations necessary for maintaining a rate of rotation of the crankset as constant as possible, so as to optimize and facilitate the effort of the cyclist.

The description which follows, given by way of example, refers to the drawing in which:

FIG. 1 is an elevation view of a bicycle provided with an example of a device according to the invention,

FIG. 2 illustrates a detail of a coded disc mounted on the front wheel,

FIG. 3 is a block diagram illustrating a mode of actuation of the device according to the invention,

FIG. 4 is a side view of an example of a front derailleur group according to the invention,

FIGS. 5 and 6 are rear views of the derailleur group of FIG. 4 illustrating the mobility of the elements of the derailleur group,

FIG. 7 is a section of a detail of the angular localization system,

FIG. 8 is a rear view of a second example of a front derailleur group,

FIG. 9 is a rear view of a first example of a rear derailleur group, FIG. 10 is a side view, partially in section, illustrating the mechanism of the rear derailleur group,

FIG. 11 is a rear view of a second example of a rear derailleur group,

FIG. 12 is a side view of the derailleur unit of FIG. 11,

FIG. 13 is an example of an operating truth table of the device according to the invention,

FIGS. 14 and 15 are electrical diagrams illustrating a variant of the mode of actuation of the device according to the invention, and

FIG. 16 is an example of an electrical diagram of the comparator and of the amplifier of the motors of the front and rear derailleurs.

Although the description which follows refers more particularly to a gear selection device for the derailleurs of a bicycle, the characteristics which will be described can also refer without major modifications to the derailleurs of any other machine.

The bicycle represented in FIG. 1 comprises a front plate derailleur 5 and a rear pinion derailleur 6, both electronically controlled, each derailleur being provided with an electronic device for reading a digital or analog electrical signal, indicating the derailleur position. It also includes a set of standard rear sprockets 7, as well as a set of front chainrings 8. Production of electrical energy can be ensured by means of a mini-generator 9 mounted on the lower wheel of the chain tensioner of the derailleur. rear, so as to supply a static aggregate for storing the electrical energy of the system and to confirm that the pedalboard is in rotation. Said aggregate can be arranged inside an electronic unit 10 mounted for example inside the vertical tube of the bicycle. A general indicator board 16 can be arranged on the handlebars.

As shown in FIG. 3, the servo system 11 of the front derailleur and the servo system 12 of the rear derailleur are equipped with positioning sensors, providing digital or analog information identifying the pinion or the chainring concerned. These data are transmitted to an electronic card, fitted with a processor, capable of processing the data. This electronic card, which can also be mounted inside the housing 10, is capable of managing the system for regulating the supply voltage of the engine and performing the conjunction-disjunction of the generator-accumulator assembly.

A coding disc 1 - (Figure 2) is mounted on the axis of the front wheel, integral in rotation. The disc 1 comprises for example a coding distributed around its periphery. A sensor 2 is mounted on the front fork so as to read the data of the coded points of the disc and to transmit them to an electronic processing circuit 3. The mounting of the coded disc on the axis of the rear wheel, in cooperation with a sensor placed on the rear fork is also possible.

The parameters processed by the electronic card can for example be the following:

fixed input parameters to be programmed when mounting the pinions and chainrings:

- wheel diameter

- number of teeth Tl, T2 and T3 of the chainwheels

- numbers of teeth tl to t8 of the rear sprockets

programmable parameters: - ideal rate of rotation P of the crankset in revolutions / minute

- dead zone O (overlap)

- type of program to be chosen by the cyclist (walking, training, running)

parameters analyzed by the electronic card for the management of an optimal cadence:

- instantaneous speed V of the bicycle in km / h

- T plate engaged at the front

- pinion t engaged at 1 • rear

- rate of rotation p of the crankset in revolutions / minute

- indication of the inclination of the drive chain

- indication of the slope / gradient of the road

- position on or off of the full automation

any additional parameters:

- temperature

- applied torque

- cyclist's heart rate

calculated parameters:

- average cruising speed in km / h

- counter totalizing the total distance of the introduced program traveled in km

- daily distance counter in km

- total journey time in hours, minutes and seconds

- daily journey time in hours, minutes and seconds

- travel proportions in flat, upward, downward configuration, according to data from an inclination sensor.

Two levers 4 and 4 'can be arranged on the handlebars near the handles. These levers are arranged so that their actuation deactivates the automation and allows manual gear selection, useful for example during races, to adapt the cadence of the crankset in the event of starting, or during ascents in extreme circumstances. We will now describe the operation of the automatic derailleur.

A high number of coded points on disk 1, for example 10, can be chosen. In this case, the capture unit 2 gives a signal every tenth of a turn of the wheel. Thus, even at very low speed, for example on a steep hill, the number of pulses is sufficient to give a valid account of the speed.

The processor is arranged to calculate the speed V of the bicycle in km / h, the ratio i and the cadence of the crankset p in revolutions / minute according to the following formulas:

V = (I x D x π x 3.6) / n

where I = number of pulses per second,

D = wheel diameter in meters and n = number of pulses per wheel revolution

i = T / t

where T is the number of teeth of the engaged front plate and t the number of teeth of the engaged rear sprocket

p = (1x6) / i / n

The ideal cadence P of the crankset having been memorized in the computer, when the instantaneous speed p of the crankset is lower or higher than the ideal speed P programmed, the gear ratio i changes automatically when the computer determines that a neighboring gear would give a bottom bracket speed closer to the ideal speed P than the current gear. An overlap must be programmed to create a dead zone to avoid gear changes for too small differences in pedal speed. When a gear change must be made, the processor (Figure 3) gives a signal (SCI or SC2) to the comparator of the front derailleur or the rear derailleur, which in turn controls the amplifier 11 or 12 of the front engine 22 or rear 52. The amplifier 11 or 12 of the engine transmits the power from the accumulator to the engine. A digital or analog feedback position sensor 19, 19 ′ then emits a signal (SE1 or SE2) to inform the comparator of the position of the front derailleur, respectively of the rear derailleur.

When the calculated programmed signal and the feedback signal are equal, the comparator signal is zero and the amplifier stops the motor.

The electronic card is programmed to avoid chain positions such as Tl - t7 or t8, and T3 - t2 or tl, so as to avoid energy losses or chain wear. He will also be assisted in this function by an electro-mechanical chain controller.

As shown in FIGS. 4 to 12, the front and rear derailleurs can be derailleurs of the standard parallelogram type, in which the control of the parallelogram, conventional ent with cable (bowden cable connected to the handlebars or to the frame tube), is advantageously replaced by a servo device comprising an electric motor disposed at the level of the derailleur and actuating a reduction gear, the output of the reduction gear comprising an eccentric which controls the parallelogram by means of a connecting rod arranged in the plane constituted by the parallelogram.

The parallelogram motor control device is particularly advantageous compared to the control devices proposed so far, because it eliminates the bowden cable. On the other hand, as the spring usually provided on the devices which have been proposed so far is not no longer necessary, the force required for the offset is very low and a low power motor can perform the lateral translational movement of the chain.

An example of a front derailleur group is shown in FIGS. 4 to 6. The motor-reduction unit 22 is mounted on a support element 21 fixed to the frame (not shown) of the bicycle, for example by means of a screw 20 The motor-reducer assembly drives a crankshaft 24 acting on a driving rod 25 which controls the translation of the guide element 31 of the chain by means of an elbow arm 26 and an intermediate rod 29, the arm 26 and the connecting rod 29 being the constituent elements of the parallelogram. To this end, the arm 26 is mounted in rotation about a fixed axis 27 integral with the engine support 21, one of its ends being mounted in articulation at the end 28 of the driving rod 25, its other end being mounted in articulation 33 on the guide element 31. The intermediate connecting rod 29 is mounted at one of its ends in articulation around a fixed axis 30 secured to the motor support 21 and at its other end in articulation 32 on the element of guide 31.

The electro-mechanical application principle described above is susceptible to various modifications.

According to another embodiment of the front derailleur group, shown in FIG. 8, the motor 22 'actuates a reduction gear acting on an eccentric 24' which controls a driving rod 25 * arranged outside the parallelogram 26 *, 29 ' and which acts at one of the lower axes of rotation of the parallelogram. Also shown in FIG. 8 is the chain 36 and the chain guide, the seat tube 37 and the front plate 38.

An example angular localization device is shown in detail in FIG. 7, in which the support 21 of the motor-reduction unit 22 is shown, as well as the crankshaft 24 and the driving rod 25. This device comprises a Reed sensor element 43 (known per se) controlled by the passage of a magnetic activator element 42 mounted at the end of the axis 40 of the engine assembly - reducer.

It can be noted that the indication of the position of the motor shaft can also be obtained by reading an analog signal emitted by a potentiometer with a track integral with the motor shaft.

An example of a rear derailleur group is shown in FIGS. 9 and 10. It comprises on the one hand an upper element 50 fixed to the rear element of the frame, for example by means of a screw, this element 50 constituting the only part fixed derailleur, and on the other hand a lower element 61 (of the type known per se). The displacement of the lower element is ensured by the deformation of a parallelogram constituted by two connecting rods 56 and 57 actuated by a driving rod 55 itself actuated by an engine-reduction unit 52 via a crankshaft 54. The driving rod 55 is articulated at one of its ends around an axis 58 secured to the upper element 50 and at its other end around an axis 65 secured to the crankshaft 54. The axis 58, which constitutes one of the two fixed points of the parallelogram, is also the axis of articulation of the connecting rod 57.

The rear derailleur group can include an angular localization device identical to that illustrated in FIG. 7.

A second example of a rear derailleur group is shown in FIGS. 11 and 12. This group includes a motor 82 which actuates a reduction gear 83 acting on an eccentric 84 which controls the parallelogram 86, 87 by means of a diagonal connecting rod 85, eventually adjustable. A position sensor 89 is also visible in FIG. 11.

The electrical diagrams illustrating a mode of actuation of a device according to the invention shown in Figures 14 and 15 refer more particularly to a device comprising a front derailleur group as described in relation to Figure 8 and a rear derailleur group as described in relation to FIGS. 11 and 12.

An example of an electrical diagram of the comparator and the amplifier of the front and rear derailleur motors is illustrated in Figure 16.

The device according to the invention makes it possible to manage automatically and with maximum efficiency the energy of the cyclist without the latter having to intervene at the level of the gear change, in all the possible configurations. Carried out according to the preferred embodiment which has been described, the device according to the invention has the significant advantage of being based on a position transfer system by mobility of a parallelogram which is a proven system, probably the best known. The result is a purely mechanical, electro-mechanically controlled system. Electronic processing is not done at the derailleur, but at a higher level, which allows to separate very clearly all electronics from mechanics.

In addition, as described, the cyclist only needs to manually change the speed so that the command previously ordered by the computer is immediately canceled and the manual command is immediately executed. Of course, in this case the cyclist must then reactivate the automation control to again benefit from full electronic assistance.

According to an execution variant, optional external parameters of Kick up (KU) and Kick down (KD) can be introduced, for example by means of an external button control, placed for example near one of the handlebars. In this case, said command comprises a button for controlling the shift of the derailleur to the next higher position (kick up) and a button for switching the derailleur to the previous lower position (kick down) for changing the value of the rate of rotation. ideal P of the crankset in order to adapt it to exceptional circumstances (races, climbs in extreme circumstances), without deactivating the automatic electronic assistance.

Among other advantages, the device according to the invention allows the sportsman to choose an ideal cadence of the pedals with low constraints (fast cadence) at the start of the season and to gradually modify these constraints according to the evolution of his physical form, or determine a particular form of training at any time. Likewise, the choice of a specific constraint program is possible, which makes it possible to orient the workouts with precision.

Claims

claims

1. Gear selection device for machines powered by muscular force, in particular for bicycles, comprising a crankset provided with at least one chainring and at least one derailleur as well as control means for selecting the gears, characterized in that '' it includes a computer (13) programmed to calculate the speed V of the bicycle, the multiplication ratio i and the cadence of the crankset p according to the following formulas:

V = (I x D x π x 3.6) / n

where I = number of pulses per second, D = diameter of the wheel in meters, and n = number of pulses per revolution of the wheel

i = T / t

where T is the number of teeth of the plate concerned and t the number of teeth of the rear sprocket concerned

P = (Ix60) / i / n

and in that it includes data reading means and calculation means, these means being arranged to maintain an optimal rate of rotation of the pedal of the machine and in particular to optimize the operations necessary to maintain a rate of constant and previously programmed pedal rotation.

2. Device according to claim 1, characterized in that the computer is programmed to memorize the ideal speed P of the crankset, compare the instantaneous speed of the crankset with the ideal speed P programmed and, when said instantaneous speed is lower or higher than said ideal speed P programmed, automatically control the gear ratio change i when it determines that a neighboring gear would give a bottom bracket speed closer to the ideal speed P than the current gear.

3. Device according to one of the preceding claims, characterized in that it comprises a front derailleur (5) and / or a rear derailleur (6) of the parallelogram type and in that at least one of the front derailleurs and rear comprises a device for controlling the movement of the parallelogram (26, 29; 56, 57) comprising an electric motor (22; 52) disposed at the level of the derailleur and actuating a reduction gear, the output of the reduction gear comprising an eccentric (24; 54) which controls the movement of the parallelogram via a driving rod (25; 55).

4. Device according to claim 4, characterized in that the device for controlling the movement of the parallelogram of the rear derailleur comprises an adjustable diagonal connecting rod (55) or not (85).

5. Device according to one of claims 3 or 4, characterized in that the device for controlling the movement of the parallelogram of the front derailleur comprises a diagonal drive rod (25; 25 ') disposed outside the parallelogram and acting at the level of one of the lower axes of rotation of said parallelogram.

6. Device according to one of the preceding claims, characterized in that it comprises comparators (14, 15) of signals of the actual position and of the calculated ideal position of the front derailleur and / or the rear derailleur arranged in a box (10) also containing an electronic card and amplifiers (11, 12) of the front and rear derailleur motors.

7. Device according to claim 6, characterized in that the box (10) also contains a source of electrical energy.

8. Device according to one of the preceding claims, characterized in that a mini-generator (9) is mounted on the roller of the lower guide of the rear derailleur, so as to supply the power source, controlled by the system of regulation.

9. Derailleur as part of the device according to one of claims 1 to 8, characterized in that it comprises a front derailleur (5) and / or a rear derailleur (6) of the parallelogram type and in that the at least one of the front and rear derailleurs comprises a device for controlling the movement of the parallelogram (26, 29; 56, 57) comprising an electric motor (22; 52) disposed at the level of the derailleur and actuating a reduction gear, the output of the reduction gear comprising an eccentric (24; 54) which controls the movement of the parallelogram by means of a diagonal driving rod (25; 55).