WO2006018488A1 - Frictionless, mechanical variable-speed drive unit comprising a linear velocity curve starting at zero - Google Patents

Abstract

The invention relates to a frictionless, mechanical variable-speed drive unit comprising a linear velocity curve starting at zero. More specifically, the invention relates to a system for the transmission and variation of a mechanical rotational movement. The inventive system comprises a drive shaft (1) which rotates a planet gear (7a) around the axis thereof. According to the invention, the planet gear (7a) meshes with two circle-forming chains (5a and 5'a), the resultant movement of which is transmitted to the output shaft (8) by means of a double gimbal arrangement (21).The diameter of rotation of the planet gear (7a) and the circle formed by the two chains changes as a function of the desired output velocity. The movement is transmitted in a continuous, frictionless, slip-free manner as is usual in said type of variable-speed drive unit having a linear output velocity starting at zero.The inventive device is particularly suitable for systems that require the transmission of a high torque, engine braking and slow-speed start-up starting from zero.

Description

MECHANICAL SPEED VARIATOR WITHOUT FRICTION, WITH A LINEAR SPEED CURVE AND STARTING FROM ZERO

The present invention relates to a mechanical device for transmitting a rotational movement and varying the output speed with respect to the input speed.

The current mechanical variable speed drives do not allow to have an output speed starting from zero (at zero speed they are disconnected) which makes it necessary to resort to starting systems (clutch, ....) especially for the machines with high inertia. These drives operate by sliding or friction of different parts (belts, cones, chains of special shapes, V-shaped pulleys ...). The load, especially as it is high, makes more or less skate these different parts, which causes an unstable output speed, a nonlinear acceleration, poor performance and therefore strongly limits the maximum torque that can be transmitted .

The goal is to find a system that works without friction, can transmit a large torque, and has an output speed curve from zero.

The mechanical device according to this invention achieves this goal.

According to a first characteristic, this device is remarkable in that the principle for varying the speed of rotation transmitted by any motor (see FIGS. 1, 2 and 3) is to make a satellite gear (7a) evolve around a driving shaft (1), which pinion (7a) meshes with two chains (5a and 5 'a) forming a gear with internal teeth of variable diameter, the resulting movement being transmitted to the output shaft (8) by means of a double gimbal (21), the variation of speed s Obtaining by the variation of the revolution diameter of said satellite pinion and the diameter of the gear with internal teeth formed by the two chains (5a and 5 ' at).

Presentation of the different figures:

Fig.l: perspective view of the assembly, which illustrates the maintenance of the chains, the two power and control circuits, and the revolution of the satellite gear with Vs = Ve (D = d)

Fig.2: Perspective view from another angle.

Fig.3: perspective view of the assembly, which illustrates the maintenance of the chains, the two circuits, the revolution of the satellite gear with Vs = 0 (D = 0)

Fig.4A: Plan view of the gear with variable diameter formed by the two chains with Vs = Ve Fig.4B: Next view A of the gear with variable diameter formed by the two chains

Fig.4C: Next view B of the gear with variable diameter formed by the two chains

Fig.4D: Axial view of the gear with variable diameter formed by the two chains

Fig.5A: Plan view of the gear with variable diameter formed by the two chains with Vs = 0

Fig.5B: Next view A of the variable diameter gear formed by the two chains Fig.5C: Next view B of the variable diameter gear formed by the two chains

Fig.5D: Axial view of the gear with variable diameter formed by the two chains

Fig.6A and 6B: Smooth washer details.

Fig.7A and 7B: Washer details with oblong holes.

Fig.8A and 8B: Snail screw details. Fig.9A and 9B: Details of a single jaw.

Fig.lOA: Satellite pinion details, cam-shaped shaft and spring ring sectional view Fig.lOB: Next view B of Fig. 10A of the planet wheel, cam-shaped shaft and spring ring

Fig.1OC: C following view of Fig.1OA of the cam-only axis

Fig.lOD: Next view A of FIG. 10A of the planet pinion, teeth, cam-shaped shaft and spring ring FIG. 1A: sectional view of the system of variation of the diameter of revolution of the planet wheel with

Vs = O

Fig.l IB: sectional view of the system of variation of the diameter of revolution of the planet wheel with

Vs = Ve

Fig.12: Sectional view of the tensioner / inverter system (4). The system (4 ') is identical. Fig.13 A: plan view of the copy room

Fig.l3B: following view A of FIG. 13A of the copy room

Fig.14A: plan view of the connecting rod and the freewheel

Fig.l4B: next view B of fig.l4A of the connecting rod and the freewheel

FIG. 15: exemplary embodiment, sectional view of the following assembly A of FIG. 16 FIG. 16: exemplary embodiment, sectional view of the assembly B of FIG.

Fig.l7A: exemplary embodiment view of the transmission system of the control movement and synchronism.

FIG. 17B: view O of FIG. 17B of the transmission system of the control and synchronism movement.

Perspective views represent the system as a whole, where only the innovative and understanding parts are represented.

The transmission of the movement is carried out continuously, without friction or slippage, being able to support a large torque, with a linear output speed curve starting from 0 and a maximum speed equal to the input speed or more (function of mechanical realization). This system makes it possible to have a motor brake at any speed and a total brake when the output speed is equal to 0, the main advantages being a linear speed curve starting from zero, a good efficiency and the possibility of transmit a significant couple.

The system includes a main housing which encloses two distinct circuits: a power circuit and a control circuit.

The power circuit that transforms torque and speed while keeping the power constant. It breaks down as follows:

- An input shaft (1) which receives the movement of the motor at one end and the other holding and makes evolve about its axis a pinion satellite (7a). D also transmits the necessary movement to the control circuit. - A subset (see fig.lOA, 10B, 10C, 10D) pinion satellite (7a) plus cam (7b), the heart of the system. This planet pinion (7a) has two rows of teeth (7c) retractable, a cam-shaped axis (7b) which holds and evolves around the input shaft (1). The planet gear (7a) transmits the resulting motion to the output shaft (8) via a double gimbal (21).

Two symmetrical subassemblies (5 and 5 ') (see FIGS. 4A, 4B, 4C, 4D and FIGS. 5A, 5B, 5C, 5D), each comprising a chain (5a and 5'a) against which engages the satellite pinion (7a), the

jaws (5b and 5TJ) which hold and guide the chain, a washer (6) common to the two subassembly against which the jaws lean, a washer with oblong holes (5d and 5'd) which guide the jaws and a tensioner (4 and 4 ') which repositions the chain.

The control circuit (see flg: 16, 17A, 17B) which allows the adjustment of the speed while ensuring the proper positioning and synchronism of the various power elements. H comprises in main elements:

- A pinion (14) which meshes with the input shaft (1) and which transmits the movement and the necessary synchronism to the control circuit.

- A control handle (10) that adjusts the speed, this handle acts on power subsets by positioning them at the desired speed.

- A part (26) with a groove whose shape is the copy of the value necessary for the proper positioning of the chains (5a and 5'a).

- A set of different elements such as inverter (3 and 3 '), rods (28 and 28') freewheel (30 and 30 '), rods (42 and 42'), cleat (48), bistable (46). .. which transmit this value and actuate inverter (3 and 3 ').

It is therefore necessary to describe the characteristics of the satellite gear revolution system and the speed variation.

See fïg. 4, 5 and 15: The planet pinion (7a) meshes with a kind of gear with internal teeth of variable diameter. This gear is made by two identical subsets (5 and 5 ') forming 180 ° each, juxtaposed so as to have in a axial view a circle. Each subset comprises a chain (5a and 5'a), jaws (5b and 5 * b), a snail screw (5c and 5'c) and a washer with oblong holes (5d and 5'd). The chain (5a) is held and guided by the jaw group (5b). To do this each jaw has at its end a special shaped recess in which the chain (5a) slides. This group of jaws (5b) is sandwiched between two washers (5d and 6) which hold and guide them. On one side, the group of jaws (5b) bears on the smooth washer (6), common to both sets (5 and 5 ') while the other side which has two pins per jaw takes support on the washer (5d ) which has oblong holes. These tenons have a dual role: a guide role through the oblong holes of the washer (5d) and a role of moving the jaws via the snail screw (5 c) which is pressed against the washer (5d) and which turns in one direction or the other depending on whether one is in an acceleration or deceleration phase. This screw (5c) is actuated by the adjusting handle (10) via a gear assembly (9e, 16, 17 ').

See Figs. 10A, 10B, 10C, 10D: The planet pinion (7a) has two identical and retractable parallel tooth tracks (7c). These teeth sliding in their housing (7c) are retractable so that, in the case where the speed range is close to 0, so in the case where the diameter of the circle formed by the two chains (5a and 5'a) is near the pitch diameter of the satellite pinion, the satellite pinion can move from one chain to another within this circle. This function is provided by the axis (7b) of the cam-shaped planet gear, by teeth (7c) which are slidably mounted on the body of the planet gear (7a) and by a spring ring (7d). The top of the cam (7b) is oriented to push the teeth (7c) which meshes and only these against the chain. All the teeth of each row being linked together by a spring ring, the pushed teeth pull the others through the ring and retract them. The planet gear has two rows of teeth, mechanically linked by the body of the planet gear, to be continuously driven by the internal gearing formed by the two chains by passing alternately from one to the other.

See fig.HA and HB: The diameter of revolution of the planet gear (7a) at the end of the motor shaft (1) is variable. This evolution of the diameter of revolution of the planet pinion which is done by the axis (7b) which supports it (axis in the form of cam) and which slides at the end of the motor shaft (1) is ensured by the screw (11) fixed at the end of the motor shaft (1) and a set of gears (9). At a constant speed (9a) rotates at the same speed as the motor shaft (1). An action on the speed adjustment handle (10) turns (9e). The movement of (9e) is either add to or subtract from the speed of rotation (9a) through (9d) then (9c) then (9b), which causes a rotation of the screw (11). ) which pushes or pulls on the cam-shaped axis (7b), support of the planet gear.

On a rotation turn of the input shaft (1) is 360 °, the chains (5a and 5'a) have two alternative operating phases of 180 ° each:

Phase A chain drives in rotation about the cam-shaped axis (7b) the satellite pinion

(7a) which meshes with her.

Phase B the chain is repositioned. When one channel is in phase A, the other is in phase B and vice versa.

During phase A, the tensioning systems (4 and 4 ') respectively block the chains (5a and 5'a) so that they can not be driven by the planet pinion (7a).

- During phase B, so that the satellite pinion (7a) can pass from one chain to another while meshing properly, it is necessary to reposition these chains so that the links of a chain to another are aligned and form a continuity.

Repositioning strings is done in the following ways:

- The chain is advanced by a value y from 0 to b / 2, then moved back by a value y 'from b / 2 to b. Where we have: - a = no of the string x = number of links inscribed in the circle formed by the two chains, b = the index b corresponds to the cases where the 0 formed by the two chains comprises an integer of links. y = a (x - integer part of x) and 0 <y <a / 2 - y '= -a (x- integer part of x) + a and a / 2> y'> 0

Chart 1

b/2 bO bl b2 0 formé par les deux chaînes - L'évolution du diamètre et la bonne tension des chaînes se font sur les deux phases de fonctionnement par la poignée de réglage (10) qui agit directement sur les vis escargots (5c et 5'c)et sur les tendeurs (4 et 4').

b / 2 bO bl b2 0 formed by the two chains - The evolution of the diameter and the good tension of the chains are done on both phases of operation by the handle of adjustment (10) which acts directly on the snail screws (5c and 5'c) and on the tensioners (4 and 4 ').

All the synchronism required for proper operation is given by the reciprocating control motion generated by the motor shaft (1).

See Figs.12, 13A, 13B, 14A, 14B: The chain repositioning function is provided by the tensioners (4 and 4 '), the inverters (3 and 3') and the copy part (26). The value necessary for the repositioning of the chains is measured by (26) and transmitted to the inverters (3 and 3 ') respectively by two connecting rods (28 and 28') on which are mounted two freewheels (30 and 30 '), then the inverters (4 and 4 ') transmit it to the tensioners (3 and 3'). The inverters are controlled via a bistable (46) by the speed control handle (10).

See fïg: 15. The functions of blocking, tension and rotation of the chains are provided by the tensioning systems (4 and 4 '). Each system comprises a casing (4) actuated by two screws (13) themselves actuated by (17) then (16) then (9e) then (10). The housing serves as a tensioner. This casing surrounds a wheel assembly (4b) and worm (4c) with a ratio such that the driven wheel can not become a driver, which ensures the locking of the chains, while the output gear (4a) holds the chain and transmits the rotational movement.

See Fig. 13A, 13B, 16, 17A and 17B. The function for measuring and transmitting the value necessary for the repositioning of the chains is done by the copy part (26). This piece has a special shaped groove which following the speed instruction measures the value necessary for the proper repositioning of the chains (5a and 5'a). The wheel (14) driven by the shaft (1) reciprocates the workpiece (41) via the connecting rod (40). This reciprocating motion is modulated by the workpiece (26) as follows: The workpiece (26) which is mechanically linked to (9e) is actuated by the adjusting handle (10) .The rotation of (26) causes a linear movement of (44) which is guided by (51). The displacement of (44) positions the connecting rods (40 and 40 ') on the workpiece (41) so that when (44) is on the point A of (26), the connecting rods (42 and 42') being in the axis of rotation of (41) results in no movement, which corresponds to a chain advance = 0. Then as the rotation of (26), the connecting rods (42 and 42 ') move along (41) through (44) following the course of the (26) groove. When (44) reaches the point B of (26), (41) transmits a movement of maximum amplitude to the link (28) via (42). This maximum movement corresponds to an advance of ¹ A step of the chain. A rotation turn of (26) corresponds to the evolution of the revolution diameter of the planet wheel of an integer number of links "n" included in this diameter at "n + 1" or "n-1" depending on the we are in the acceleration or deceleration phase.

See Figs. 14A, 14B, 17A. The function for transmitting and transforming the movement necessary to reposition the chains of the part (26) to the inverters (3 and 3 ') is done by a link assembly (28) plus freewheel (30). The link (28) receives the reciprocating and linear motion generated by the workpiece (26), while the freewheel (30) converts this reciprocating motion into a unidirectional rotary motion and transmits it to the inverter. See fig: 17A, 17B. The function to reverse the repositioning movement of the chains is done by two inverters (3 and 3 '). Each inverter is controlled by the adjustment handle (10) via a bistable assembly (48) and levers (42 and 42 ') all in synchronism with the input speed.

When the planet gear (7a) is aligned with the axis (1) of the motor shaft (see Fig. 3), the output speed is zero, then, depending on the diameter of revolution of the planet gear, the output speed Vs is :

Vs = Ve (D / d)

Or we have: Vs - ^ exit speed Ve -> entry speed D - ^ diameter of revolution of the satellite gear d -> pitch diameter of the satellite gear

Example of realization:

In this embodiment, it is considered that the ratios of screws and other gears are set so as to have a correct displacement of the different elements.

Operation

A-Transmission of movement: see fig.15

The motor rotates the input shaft (1). At the end of the shaft (1) slides the part (7b) which itself holds the pinion (7a). The piece (7b) is held and moved by the screw (11).

The planet pinion (7a) driven in rotation about the axis (1) is alternately mesh with the chains (5a and 5'a) at an offset of 180 °.

This results in a rotation movement of the planet gear (7a) about its axis. This rotational movement is transmitted to the output shaft (8) via the slider gimbal (21).

B-Svstème to change the diameter formed by the two chains: see fig.4, 5, and 15

The system is identical for the two chains (5a and 5'a).

Recall :

- Phase A -> the satellite pinion meshes with the chain. - Phase B - the chain is no longer in contact with the satellite gear. Repositioning the chain. On the portion where the satellite pinion meshes, the chain (5a) is guided and held by the jaws (5b). These jaws are actuated by the snail screw (5c).

Similarly on the part where the pinion meshes the chain (5'a) is guided and maintained by the jaws (5Ta). These jaws are actuated by the snail screw (5'c). The snail screws (5c and 5'c) are actuated by (17 '), actuated by (16) then by (9e) then by (10) which is the adjustment handle.

The linear guidance of the jaws (5b and 5TJ) is provided by the guide plates (5d and 5'd) which have oblong holes.

The washer (6) is used to hold the jaws in good position against the guide washers (5d and 5'd).

C-Systems tensioner / advance chain (4 and 4 '): see fig.12

The two systems (4 and 4 ') are identical and have three distinct roles:

1-A role of tension of the chains, according to the diameter formed by them, the tensioner / advance chain move so as to have the chains always well tensioned. The action on the tensioner (4) is done by means of the screws (13) themselves operated by (17) then (16) then (9e) then (10).

The action on the tensioner (4 ') is done by means of the screws (13) themselves operated by (17') then (16) then (9e) then (10).

2-A role of brake so that the chain is not driven by the pinion satellite during phase A. The assembly (4) being formed by a wheel (4b) and worm (4c), the driven wheel (4b) ) can not become a driver so the chain can not drive the pinion (4a).

3-A role of advance of the chain to reposition the chain in good position during the phase B. The pinion (4a) is driven by the wheel (4b) itself driven by the screw (4c) which is actuated by the double gimbal with slider (12).

D- Repositioning the chain:

Operation: see fig.12, 15, 16, 17 and 17A

The wheel (14) driven by the shaft (1) reciprocates the workpiece (41) via the connecting rod (40).

(41) transmits its movement to (42 and 42 '). These two rods have an identical operation but out of phase by 180 °.

The rod (42) actuates the lever (28) which transmits a rotational movement to the input shaft (3a) of the inverter (3). This rotation movement is only transmitted in one direction thanks to the freewheel

(30).

Then the inverter, according to its position, transmits a movement AV or AR to the worm (4c) of the tensioner / advance chain through the double gimbal slider (12).

Finally the tensioner / advance chain transmits its movement to the chain (5a). Adjustment of the extent of chain resetting: see fig.l3A and 13B.

The workpiece (26) which is mechanically linked to (9e) is actuated by the adjusting handle (10). The rotation of (26) see Fig. 16 causes a linear displacement of (44) which is guided by (51). The movement of (44) positions the connecting rods (40 and 40 ') on the workpiece (41) so that when (44) is on point A (see Fig. 13A) of (26), the connecting rods (42 and 42 ') lying in the axis of rotation of (41) results in no movement, which corresponds to a chain advance = 0.

Then as the rotation of (26), the rods (42 and 42 ') move along (41) through (44) following the trace of the groove (26).

When (44) reaches the point B of (26), (41) transmits a movement of maximum amplitude to the link (28) via (42).

This maximum movement corresponds to an advance = a / 2 or ¹ A step of the chain.

E- Direction reverser (3 and 3 '): see Figs.12 and 16.

Operation:

The inverter is actuated with each passage of (44) at point A or B of the workpiece (26). point A corresponding to an advance of 0 and point B to an advance of a / 2. the action on the inverter must be done during phase A of the chain (pay attention to the direction of freewheeling (30)).

The adjustment handle (10) has a flat disc. This disc is divided into two parts, on 180 ° the edge is folded upwards and on the remaining 180 ° it is folded down. This disk is used to actuate the latch (48) by tilting at each passage points A and B of the part (26) which correspond to the passage from the top edge to the bottom edge and vice versa on the disk.

Each tilting of the cleat corresponds to a reversal of meaning.

An action on the speed adjusting handle (10) causes (48) to move to the transition position. This position allows the tilting of the bistable (46) which, pushed by the spring (45) which is fixed to it on (41) can slip between the hooks of (48) (a support on the beveled face of the hook pushes it back which is fixed on a tongue spring).

Once the bistable (46) has tilted, the hook (48) prevents it from going back. The bistable (46) tilts the two springs (47 and 47 '). The spring (47) guides the rod (50). The rod (50) actuated by (41) (thus in synchronism with the chain advance) changes position and pulls on the inversion mechanism (3g).

The mechanism (3g) tilts, pushes on the thrust ball (3f) which passes the conical clutch (3d) from one position to another. (3g) maintain a sufficient pressure on (3d) to allow it to adhere against (3b or 3e). (3d) has a fluted bore and slides on the shaft (3a). The rotation movement of (3a) is transmitted either by (3d) and then (3e) to the gimbal (12) or by (3d) then (3b) then (3c) which reverses the direction then (3e) to the gimbal (12). F-Satellite Gear:

See fig.HA and HB. The evolution of the diameter of revolution of the planet pinion is done by means of the screw (11). This screw slides the part (7b) which supports the pinion on the input shaft (1).

At a stable speed (without action on the adjustment handle), the input shaft (1) drives in rotation the gears (9d) which drive them (9c). (9c) therefore rotates at the same speed as (1) but in the opposite direction. (9c) drives the gears (9b) which transmit the movement to (9a). (9a) turns in the same direction and at the same speed as (1).

There is no action on the screw (11) following the movement of (1).

As soon as the speed is varied, ie an action on the adjustment handle (10), it causes a rotation movement of (9e). Since the gears (9d) are fixed on (9e), the rotational movement of (9e) comes to be added to or to avoid the rotational movement of (9c) and therefore of (9a). (9a) being geared on (11) results in a rotation of the screw (11).

Detail on the satellite gear:

See fig: 10A. So that the satellite pinion can evolve in the circle formed by the two chains, (especially near zero speed) without the teeth (7c) that are not biased cling against the chain, the unsolicited teeth part must retract.

For this the part (7b) acts as a cam and pushes the teeth (7c) which are biased against the chain (5a or 5'a).

The other teeth are retracted by the spring ring (7d) which holds them pressed against (7b).

Industrial applications:

This device can replace the gearboxes on cars or other vehicles, which will have the advantage of eliminating the different stages of speed, remove the clutch and with electronic management to operate the engine at its optimum speed . Moreover at zero speed the output shaft is automatically blocked. (parking brake).

H can also adapt to electric motors, whose characteristics are deteriorated by electronic drives, and facilitate the control of machines that require a high torque especially at startup.

It should be noted that the part "repositioning of the chain" can advantageously be replaced in whole or in part by an electronic system.

Claims

 CLAIMS: 1-Mechanical device for varying the speed of rotation transmitted by any motor characterized in that the principle is to develop a pinion satellite (7a) around a motor shaft (1), which pinion (7a) comes s meshing on two chains (5a and 5'a) forming an internally geared gear of variable diameter, the resulting movement being transmitted to the output shaft (8) via a double gimbal (21), the speed variation obtained by varying the diameter of revolution of said planet pinion and the diameter of the gear with internal teeth formed by the two chains (5a and 5'a), the transmission of the movement is effected continuously and allows to have a motor brake at any speed and a total brake when the output speed equals zero. 2- Device according to claim 1 characterized in that it comprises two separate circuits, a power circuit that transforms the torque and speed while keeping the power constant, and a control circuit that allows the adjustment of the speed, the good positioning and synchronism of different power elements. 3- Device according to claim 2 characterized in that for the power circuit it comprises two identical subassemblies (5 and 5 ') for producing an internal gear gear with variable diameter, these subassemblies each comprising a chain (5a and 5a). 5'a) which have two alternative phases of operation a meshing phase and a repositioning phase, jaws (5b and 5 * b), a snail screw (5c and 5'c) and a washer with oblong holes ( 5d and 5'd), the chain (5a) is held and guided by the jaw group (5b), each group of jaws (5b and 5 "b) is sandwiched between two washers (5d, 5'd and 6) which hold and guide, each jaw is moved by means of tenons by a snail screw (5c and 5'c) and each snail screw is actuated by the adjusting handle (10) via a set gears (9e, 16, 17 '). 4- Device according to claim 2 characterized in that for the power circuit, the pinion satellite (7a) comprises two parallel and retractable identical tooth tracks (7c) which slide in their housing to allow the planet pinion (7a) to rotate without hanging and meshing continuously, these retractable teeth are actuated by the axis (7b) of said pinion (7a) which is cam-shaped and by a ring-shaped spring (7d) which links them together. 5- Device according to claim 2 characterized in that for the control circuit, the motor shaft (1) comprises a screw (11) for changing the diameter of revolution of the planet pinion (7a), this screw (11) is fixed at the end of the motor shaft (1), and slides the camshaft axis (7b) of the planet gear (7a), it is actuated via a set of gears (9a, 9b, 9c, 9d, 9e ), by the adjusting handle (10). 6- Device according to claim 2 characterized in that for the control circuit, the system comprises two tensioners (4 and 4 '), two inverters (3 and 3'), two connecting rods (28 and 28 ') with two freewheels (30 and 30 ') and a copy part (26), the whole being slaved to a movement alternating control generated by the motor axis so in synchronism with the input speed, to reposition the chains (5a and 5'a). 7- Device according to claim 2 characterized in that for the control circuit the two tensioner systems (4 and 4 '), each comprise a housing (4) actuated by two screws (13), which serves as a tensioner, this housing casing a wheel assembly (4b) and worm (4c) which receives the repositioning movement and transmits it to the chain (5a or 5'a) corresponding thereto, to tend to block and reposition the chains. 8- Device according to claim 2 characterized in that for the control circuit the copy part (26) comprises a specially shaped groove which following the speed instruction measures the value necessary for the proper repositioning of the chains (5a and 5'a ) and retransmits it in synchronism with the rotation of the motor shaft (1). 9- Device according to claim 2 characterized in that for the control circuit there are two sets of rods (28 and 28 ') plus freewheels (30 and 30'). The connecting rod (28) receives a reciprocating and linear movement, modulated and generated by the workpiece (26), while the freewheel (30) converts this reciprocating and linear movement into a unidirectional rotary motion and transmits it to the inverter (3). ) for the correct repositioning of the strings. 10- Device according to claim 2 characterized in that for the control circuit there are two inverters (3 and 3 '). Each inverter is controlled by the adjustment handle (10) via a bistable assembly (48) and levers (42 and 42 ') all in synchronism with the input speed, to reverse the repositioning movement of the chains. 11- Application of the mechanical device according to any one of claims 1 to 10 to the design of gearbox for vehicles. 12- Application of the mechanical device according to any one of claims 1 to 10 to the design of transmission elements for electric motor.