Patent ID: 12187380

With reference to the drawings, they serve solely to illustrate embodiments of the invention with the aim of better clarifying, in combination with the description, the inventive principles on which the invention is based.

DETAILED DESCRIPTION OF AT LEAST ONE PREFERRED EMBODIMENT

The present invention relates to a transmission apparatus for gear reversal for means of transport, preferably pedal means of transport.

With reference to the figures, a transmission apparatus for gear reversal has been generically indicated with the number 1.

The other numerical references refer to technical features of the invention which, barring indications otherwise or evident structural incompatibilities, the person skilled in the art will know how to apply to all the variant embodiments described.

Any modifications or variants which, in the light of the description, are evident to the person skilled in the art, must be considered to fall within the scope of protection established by the present invention, according to considerations of technical equivalence.

FIG.1illustrates a transmission apparatus1comprising gear reversal for means of transport, preferably pedal means of transport.

In particular, the apparatus1comprises a shaft of the pedal cranks10(better seen at least inFIG.2), a second transmission shaft20, a third transmission shaft30, an activation device40and a motorisation means60(better seen at least inFIG.2).

The third transmission shaft30is configured to rotate about a third longitudinal axis Z and a plurality of third transmission members31,32arranged in sequence along the third longitudinal axis Z. Each third transmission member31,32is advantageously configurable between a non-selected condition, in which it is able to rotate freely about the third longitudinal axis Z, and a selected condition, in which it is able to rotate about the third longitudinal axis Z in a manner solidly constrained with the third transmission shaft30.

The second transmission shaft20is configured to rotate about a second longitudinal axis Y parallel and spaced apart from the third longitudinal axis Z, and a plurality of second transmission members21,22arranged in sequence along the second longitudinal axis Y and axially arranged at a respective third transmission member31,32of the third transmission shaft30. In detail, the second transmission members21,22are integral in rotation with the second transmission shaft20about the second longitudinal axis Y.

Additionally, at least one of the third transmission members31and at least one of the second transmission members21are engaged with each other to establish a predetermined transmission ratio between the third transmission shaft30and the second transmission shaft20. Preferably, each of the third transmission members31,32is engaged with a respective second transmission member21,22.

The shaft of the pedal cranks10is configured to rotate about an axis of the pedal cranks X parallel to the third longitudinal axis Z and the second longitudinal axis Y. Furthermore, the shaft of the pedal cranks10comprises a main gear wheel14(better visible inFIG.3) configured to transfer the rotary motion of the same shaft of the pedal cranks10to the second transmission shaft20by an inlet pinion24arranged on said second transmission shaft20and engaged with the main gear wheel14.

Advantageously, the main gear wheel14and the inlet pinion24are splined on the respective shaft so as to directly transfer a torque (for example deriving from pedalling) from the shaft of the pedal cranks10to the second transmission shaft20.

Preferably, the inlet pinion24splined on the second transmission shaft20has dimensional and mechanical features which can be the same as or different from the second transmission members21adjacent thereto. According to an aspect of the invention, the main gear wheel14or the inlet pinion24comprises a free wheel configured to rotate the amin gear wheel14or the inlet pinion24in a manner solidly constrained to the shaft of the pedal cranks10when the latter rotates about the axis of the pedal cranks X according to a main rotation direction corresponding to the main travel direction opposite the reverse travel direction.

Preferably, the main gear wheel14comprises a free wheel configured to rotate the same main gear wheel14in a solidly constrained manner to said shaft of the pedal cranks10when the latter rotates about the axis of the pedal cranks X according to a main rotation direction corresponding to the main travel direction opposite the reverse travel direction.

Alternatively, the inlet pinion24(and not the main gear wheel14) comprises the free wheel configured to allow the transmission of motion only if the shaft of the pedal cranks10is rotated according to a predetermined rotation direction and not according to an opposite counter-rotation direction.

In general, the free wheel is advantageously associated with the pair of gears formed by the main gear wheel14and the inlet pinion24to allow the shaft of the pedal cranks10to transmit motion only when it rotates according to a preferred rotation direction and not according to an opposite direction. Thus, the free wheel is indistinctly directly associated with the main gear wheel14or the inlet pinion24.

In other words, for example referring to the preferred application of the apparatus1, the free wheel associated with the main gear wheel14allows the latter to transfer the torque generated by the cyclist's pedalling only if the pedalling is carried out according to a rotation direction which causes the advancement of the vehicle (regardless of the travel direction). If the cyclist's pedalling occurred in an opposite rotation direction, no force would be transferred to the second transmission shaft20.

The activation device40is operationally associated with the third transmission members31,32to configure in the selected condition at most only one of such third transmission members31,32to select the relative transmission ratio, for example forwards or in reverse if applied to a pedal vehicle100.

Advantageously, the motorisation means is associated with at least one second transmission member21,22or with a tertiary gear wheel25mounted on the second transmission shaft20and integral in rotation therewith. Furthermore, the motorisation means is configured to achieve a movement in a main travel direction and in a reverse travel direction of the means of transport defined when the activation device40has selected one of the second transmission members used for gear reversal22, which is engaged with a corresponding third transmission member also used for gear reversal32, so as to rotate the third transmission shaft30in the opposite direction and not the shaft of the pedal cranks10due to the presence of the free wheel associated with the main gear wheel14or the inlet pinion24.

FIGS.2,3,4illustrate a first embodiment of the apparatus1, in which the motorisation means comprises a gear reversal member2, preferably an idler wheel, interposed and engaged between the second transmission member used for gear reversal22and the corresponding third transmission member used for gear reversal32so that the third and the second transmission shaft30,20have the same rotation direction when the third transmission member used for gear reversal32is configured in the selected condition.

In other words, the third transmission members31,32are rotatably arranged along the third transmission shaft30independently of each other, so as to be able to rotate with different rotational speeds directly dependent on the respective transmission ratio defined by the coupling between the third and the second transmission member31,21,32,22. In addition, if they are configured in the non-selected condition, the third transmission members31,32are able to rotate independently of the rotation of the same third transmission shaft30.

Thereby, although the third and the second transmission members31,21,32,22are always engaged with each other (directly or, in the case of gear reversal members, indirectly), and therefore in rotation about the respective third or second transmission shaft30,20, the rotation of the third transmission shaft30is delegated to only the third transmission member31,32configured in the selected condition and, therefore, made integral with the same third transmission shaft30.

Advantageously, therefore, the apparatus1comprises at least one pair of transmission members31,21such as to define a transmission ratio whereby the third transmission shaft30and the second transmission shaft20rotate according to two opposite rotation directions and at least one pair of transmission members used for gear reversal32,22such as to define a transmission ratio whereby the third transmission shaft30and the second transmission shaft20, through the interposition of the gear reversal member2, rotate according to the same rotation direction so as to reverse the advancement direction of the vehicle.

In still other words, with particular reference to the preferred application of the apparatus1on a pedal vehicle, the pedalling of a cyclist rotates the second transmission shaft20and the relative second transmission members21,22according to a main rotation direction, while the third transmission shaft30is rotated as a function of the third transmission member31,32configured in the selected condition. Thus, in the case of configuration in the selected condition of a third transmission member31engaged directly to the corresponding second transmission member21, the third transmission shaft30will rotate in a rotation direction opposite the preceding main rotation direction.

Otherwise, in the case of configuration in the selected condition of a third transmission member used for gear reversal32engaged to the corresponding second transmission member used for gear reversal22by the gear reversal member2, the third transmission shaft30will rotate according to the same main rotation direction as the second transmission shaft20.

Thereby, the travel direction of the pedal vehicle100provided with the apparatus1depends exclusively on which third transmission member31,32is selected by the activation device40, regardless of the rotation direction of the second transmission shaft20, the latter generally always rotated by the shaft of the pedal cranks10. In other words, in the example of a pedal vehicle100such as a bicycle or a cargo-bike, the cyclist's pedalling and the consequent rotation of the second transmission shaft20will always occur in the same rotation direction regardless of the travel direction of the vehicle, while the selection or not of the third transmission member used for gear reversal32is able to determine the rotation of the third transmission shaft30in the forward or reverse direction of the pedal vehicle100.

Preferably, the gear reversal member2comprises an idler wheel interposed and engaged between the third member used for gear reversal32and the second member used for gear reversal22.

The idler wheel which defines the gear reversal member2is engaged interposed between the third member used for gear reversal32and the second member used for gear reversal22.

Such engagement is constantly engaged as it is able to compensate for the reduced radial dimensions of the third and the second member used for gear reversal32,22. Thus, during the rotation of the third transmission shaft30, the third member used for gear reversal32rotates opposite the third transmission members31as they are all rotatably independent of each other.

Advantageously, when the activation device40configures the third member used for gear reversal32in the selected condition, the other third transmission members31are configured in the non-selected condition.

According to an aspect of the invention, as illustrated inFIGS.2,3,4, the first embodiment of the apparatus1can also comprise an electric assist motor60which is constantly engaged with the second transmission shaft20by a tertiary gear wheel25mounted on the same second transmission shaft20. Consequently, the electric assist motor60and/or at least one of the second transmission members21,22comprise at least one free wheel of the motor64configured to allow the transmission of the rotational motion from the electric assist motor60to the second transmission shaft20and, simultaneously, prevent the transmission of the motion from the second transmission shaft20to the electric assist motor60. In other words, the free wheel of the motor64is configured to transmit a rotational motion from the electric assist motor60to the second transmission shaft20in accordance with a single rotation direction of the gears which form the electric assist motor60.

Since the electric assist motor60is always engaged on the second transmission shaft20, the free wheel of the motor64between the gears connecting them is advantageously arranged to prevent the cyclist from having to impart a force such as to rotate both the transmission shafts30,20of the apparatus1and the gears of the electric assist motor60when the latter is deactivated.

In other words, if the electric assist motor60is deactivated or if it provides less power than the cyclist, the rotation of the second transmission shaft20is not transmitted to the electric assist motor60, but entirely to the third transmission shaft30.

Otherwise, when the electric assist motor60is active and provides an auxiliary torque to the cyclist's pedalling, the rotation of the tertiary gear wheel25transmits such auxiliary torque to the second transmission shaft20whether or not the cyclist is pedalling.

In other words, the electric assist motor60is advantageously configured to rotate at least the transmission shafts30,20independently or to assist the pedalling of a cyclist.

Thus, upon configuration in the selected condition of a third transmission member31,32, the motor is able to activate the apparatus1and, therefore, move the vehicle in both travel directions as a function of the selected transmission ratio.

FIGS.5and6illustrate a second embodiment of the apparatus1, in which the motorisation means comprises an electric assist motor60engaged with a tertiary gear wheel25mounted on the second transmission shaft20and a control unit connected to the aforesaid electric assist motor60. More specifically, the motorisation means lacks a gear reversal member, for example an idler wheel, interposed between the third member used for gear reversal32and the second member used for gear reversal22.

The control unit is advantageously programmed to configure the electric assist motor60between a forward condition, in which it transmits to the shaft of the pedal cranks10and the third transmission shaft30a rotation in accordance with the main rotation direction, and a reverse condition, in which it transmits to the third transmission shaft30a rotation opposite the main rotation direction and, at the same time, does not transmit any rotation to the shaft of the pedal cranks10.

Preferably, in accordance with such an embodiment, the electric assist motor60is kept active by the control unit both during advancement according to the main travel direction of the means of transport, and during advancement according to the reverse travel direction.

In fact, the electric assist motor60does not have any free wheel and, at the same time, is engaged directly with at least a second transmission member21,22or with the tertiary gear wheel25.

Thus when a user pedals, inducing the rotation of the shaft of the pedal cranks10, the electric assist motor60is activated to prevent the staticity thereof from providing a motor-brake to the user's pedalling. Preferably, the greater the torque produced by the user during pedalling, the greater the current supplied to the electric assist motor60.

When it is desired to set the backward movement of the means of transport (i.e. the reverse movement according to the reverse travel direction), the control unit is programmed to reverse the movement of the electric assist motor60which, in turn, will reverse the rotation direction imparted to the second transmission shaft20, inducing the reverse movement of the means of transport.

Advantageously, the pedal cranks4will remain stationary by virtue of the presence of the free wheel on the main gear wheel14or on the inlet pinion24.

In other words, in order to be able to alternate the travel direction of the means of transport between the main travel direction and the inverse travel direction (i.e., reverse), the control unit is configured to reverse the movement of the internal gears of the electric assist motor60so that the latter is able to alternate the rotation direction transmitted to the third transmission shaft30, i.e., the shaft to which the drive wheel5(generally the rear wheel) of the means of transport is connected with a fixed snap connection by a transmission chain7.

Preferably, the electric assist motor60(for example in the case of a pedal-assisted bicycle) is powered by an external electrical source to contribute at least partially to the movement of the transmission members31,21, in an operating condition of the apparatus1.

With reference to the preferred application of the apparatus1on a pedal vehicle, the electric assist motor60is able to operate both as an assistance and autonomously without the cyclist applying any torque on the pedal cranks4, both during forward and during reverse motion depending on the second transmission member selected by the activation device40.

Preferably, the electric assist motor60is configured to pursue a constant value of driving torque on the second transmission shaft20, so that a user always exerts the same effort on the pedal cranks4, regardless of the load (required power) which the drive wheel5of a bicycle sends to the cogged crown34during a use configuration of the bicycle.

Even more preferably, the electric assist motor60is of the “brushless” type so that by means of an electronic management system, the torque delivered and the motor rotation speed can be controlled instantaneously. In order to establish a single and predetermined transmission ratio between the third and the second transmission shaft30,20, the transmission carried out by each pair of gear wheels33,23is selectively insertable by the activation device40(which, as better described below, comprises an activation disc42and a relative drum47) in order to establish a reversible connection, rotatably integral with the respective transmission shaft30,20and, therefore, to select one of the possible transmission ratios.

According to an aspect of the invention illustrated in the attached figures, the activation device40comprises a plurality of activation discs42, each of which is operatively connected to a respective third transmission member31,32. Each activation disc42is rotatably movable with respect to the corresponding third transmission member31,32about the third transmission shaft30between a first non-operating position and a second operating position. In particular, passing from the first non-operating position to the second operating position, each activation disc42is configured so as to selectively rotate integrally with the third transmission shaft30the respective third transmission member31,32from the non-selected condition to the selected condition by generating a transitory difference in rotation speed between the same selected third transmission member31,32and the relative activation disc42.

In still other words, each third transmission member31,32is associated with a respective activation disc42. Specifically, an activation disc42is associated with the third transmission member used for gear reversal32, while the remaining third transmission members31are associated with as many activation discs42.

FIG.7illustrates a possible, but not exclusive, embodiment of an activation disc42associated with the third transmission shaft30.

InFIG.7it is also possible to see a support ring39of the activation disc42and a meshing system44a-44doperatively interposed between the activation disc42and the third transmission shaft30.

In particular, the support ring39is shaped so as to support the rotation of the activation disc42about the third longitudinal axis Z. In other words, the support ring39is shaped to freely rotate about the third longitudinal axis Z with respect to the third transmission shaft30, while the activation disc42is shaped to rotate independently, as if it were sliding around the support ring39which acts as a support and guide.

Preferably, each activation disc42has a portion made of a deformable material along a perimeter edge42athereof. In a possible aspect of the invention, the deformable material is represented by an annular element42bmade of plastic material and having, for example, a circular section. More precisely, the annular element42bcan be made of a rubber-based material or of a material having mechanical and physical features similar to rubber (silicone, polyurethane, etc.).

Advantageously, the presence of the annular element42bmade of deformable material allows to avoid the use of friction braking members acting on the activation disc42and, therefore, to significantly reduce the generation of dust and the consumption of the braking member itself. In the present invention, as better described below, a rotating element48deforms the annular element42b, decelerating the activation disc42and, at the same time, such a rotating element48continues to rotate about a rotation axis T thereof.

According to a possible aspect of the invention shown inFIG.7, the meshing system comprises a meshing element44a, a lever44b, a piston44cand an elastic element44d.

Advantageously, the lever44bis integral with the activation disc42, while the meshing element44a, the piston44cand the elastic element44dare integral with the gear wheel33.

Thereby, the activation disc42and the lever44bare alternately movable to define the first non-operating position and the second operating position of the activation disc42in which, respectively, it releases and integrally connects the respective gear wheel33to the third transmission shaft30through the consequent alternating movement of the piston44cand the meshing element44a.

More precisely, when an external force slows the rotation of the activation disc42with respect to the third transmission shaft30and the selected pair of gear wheels33,23, the reversible interlocking system arranges a meshing element44athereof in contact with the third transmission shaft30to rigidly connect the gear wheel33with the third transmission shaft30. Even more precisely, a deceleration force acting on the annular element42bof the activation disc42induces, by rotating the lever44b, the movement of the piston44cwhich, in turn, moves the meshing element44aso that its shape correctly meshes in the respective seat obtained on the third transmission shaft30(better visible inFIG.10).

Preferably, the elastic element44dis a return elastic element configured to restore the non-selected configuration (i.e., the first non-operating position of the activation disc42) according to which the third transmission shaft30and the gear wheel33are rotatably disconnected.

Therefore, if the application of a deceleration between the activation disc42and the relative gear wheel33is such as to overcome the action of the elastic element44d, the meshing element44acorrectly couples with the seats of the third transmission shaft30so as to render the gear wheel33rotatably integral.

According to one aspect of the invention (also visible inFIG.8), the activation device40comprises at least one rotating element48normally spaced apart from the activation discs42. In particular, said rotating element48is operatively movable towards or away from a respective activation disc42configured to deform the portion of deformable material42bso as to generate the aforementioned transitory speed difference.

In other words, the selection of the transmission ratio occurs with the activation of the interaction between the rotating element48and the corresponding activation disc42associated with the third transmission member31,32. In the case of gear reversal, the rotating element48of the activation device40acts on the reverse activation disc42to make the third transmission member used for gear reversal32integral with the third transmission shaft30.

Thus, the activation disc42associated with the reverse transmission is installed on the third transmission shaft30in a specular manner to the other activation discs42because the rotation thereof is opposite and, consequently, the meshing system must also be driven in a specular manner.

In other words, the activation disc42associated with the reverse gear has a meshing system configured opposite that of the other activation discs42so as to be able to be activated with a reverse rotation of the third transmission shaft30with respect to the other transmission ratios.

To this end,FIG.10illustrates a possible embodiment of the third transmission shaft30.

According to a first aspect of the invention, the third transmission shaft30comprises at least a first zone36shaped to accommodate each meshing element44awhen the respective activation disc42is configured in the second operating position. In particular, the first zone36comprises a plurality of recesses70obtained radially around the third transmission shaft30, each of which has an asymmetrical shape with respect to an axis radial to the same third transmission shaft30passing through the same recess so as to assist the alternating insertion and extraction movement of the meshing element44awithin the same recess.

Preferably, the shape of each recess of the first zone36comprises a slide71adapted to assist the alternating insertion/extraction movement of the meshing element44afrom/into the recess70, and a step72adapted to act as an end-stroke during the insertion movement of the meshing element44a.

Even more preferably, the slide71and the step72are arranged consecutively along the main rotation direction of the third transmission shaft30.

According to another aspect of the invention, the third transmission shaft30comprises a second zone37also shaped to accommodate the meshing element44aof the third transmission member used for gear reversal32when the respective activation disc42is configured in the second operating position. In particular, the second zone37has a conformation specular to the first zone36with respect to the third longitudinal axis Z of the third transmission shaft30.

Preferably, the shape of each recess of the second zone37comprises a slide71adapted to assist the alternating insertion/extraction movement of the meshing element44afrom/into the recess70, and a step72adapted to act as an end-stroke during the insertion movement of the meshing element44a.

Even more preferably, the slide71and the step72are arranged consecutively along the reverse rotation direction.

In other words, the transmission shaft30has a first zone36adapted to accommodate each third transmission member31, when configured by the activation device40in the selected condition, a second zone37adapted to accommodate the third transmission member used for gear reversal32, when configured in the selected condition, and a third zone38splined to accommodate the cogged crown34.

As can be seen inFIG.10, the first zone36and the second zone37are advantageously modelled in the opposite manner since, as explained above, the third transmission members31and the third transmission member used for gear reversal32become integral with the third transmission shaft30when the latter rotates about the third longitudinal axis Z thereof according to two different and opposite rotation directions.

According to another aspect of the invention illustrated inFIG.1and in more detail inFIG.8, the activation device40comprises a drum47rotating about an extension axis B thereof. The drum47comprises on the external surface thereof a plurality of the rotating elements48each in a position such as to interact with a respective activation disc42to generate the deformation of the portion of deformable material42b.

Preferably, the drum47is cylindrical in shape and extends along the rotation axis B thereof for at least a length equal to the length of the series of gear wheels33arranged on the third transmission shaft30.

According to a further aspect of the invention, the rotating elements48are angularly divided preferably symmetrically around the extension axis B and spaced apart along the same extension axis B according to a distance equal to the mutual distance of the activation discs42.

According to an aspect of the invention, each rotating element48is structurally distinct from the drum47, which has slots in which the rotating elements distributed along the external surface are housed.

Preferably, the rotating members48consist of sensors (also numbered48) housed in slots49distributed along the external surface of the drum47according to a predetermined order.

Preferably, the slots49are obtained by mechanical machining from a full piece of material and subsequently constrained on the drum47by threaded fastening systems.

Alternatively, the slots49may be made by a printing process, for example three-dimensional additive printing.

According to one aspect of the invention, the rotating elements48are cylindrical and rotatable about the respective rotation axis T, each of which is parallel to the extension axis B of the drum47. Each rotating element48is also arranged at a radial distance from the extension axis B such that it is protruding with respect to the external surface of the drum.

In other words, the sensors48are cylindrical and the rotation axis T thereof is parallel to the rotation axis Z of the third transmission shaft30and to the extension axis B of the drum47.

Preferably, the rotation axes T of the sensors48are positioned at a radial distance with respect to the rotation axis B of the drum47so that the sensors48protrude from the external surface of the rotating drum47by a percentage with respect to the diameter thereof.

According to another aspect of the invention, the sensors48are arranged on the external surface of the drum47along a helical trajectory such as to wrap along the external surface of the same drum47in the direction of the extension axis B.

Preferably the sensors48are angularly symmetrically divided around the rotation axis B of the drum47. Even more preferably, the sensors48are spaced apart along the rotation axis B according to a distance equal to the mutual distance of the gear wheels33present on the third transmission shaft30.

In other words, the sensors48of the drum47are housed thereon so as to be positioned at the gear wheels33, during an operating configuration of the apparatus1. In particular, each sensor48of the drum47is positioned at a respective activation disc42.

According to one aspect of the invention, the drum47comprises a movement element50configured to rotate the same drum47about the axis B thereof. In turn, the movement element50has along the perimeter edge a cylindrical portion provided with a plurality of depressions51numerically equal to the number of rotating elements48housed on the drum47and such as to allow the angular position assumed by the drum47itself to be identified.

Alternatively, the latter operation can be implemented using an optical sensor configured to detect specific reference points and the movement thereof, such as notches arranged in place of the aforementioned depressions.

Preferably, the movement element50comprises a gear wheel configured to be engaged with another gear wheel, for example, connected to the shaft of an electric movement motor arranged to correctly move and position the drum47. Such an electric motor can be of the brushless or DC or stepper type.

According to one aspect of the invention (visible inFIG.9), the apparatus1comprises a micro-switch61(or a similar component in operation) such as to perceive information on the angular position of the drum47, for example following the selection of a particular transmission ratio, by the interaction of a portion of the micro-switch61in a depression51of the movement element50of the drum47.

Preferably the micro-switch61is connected and interacting with an electric motor and/or with the electric movement motor of the drum47.

Even more preferably, the depressions51of the movement element50are adapted to interact with a position sensor, for example, made with a lever having an end provided with a roller and an arm connected to an electronic micro-switch61, or other types of optical positioning sensors, so as to switch it based on a certain operating condition.

Preferably, the micro-switch61is connected by electrical wiring to a small electronic display, positioned in view of a bicycle user, to provide the information related to the transmission ratio inserted in that moment.

According to an aspect of the invention, the apparatus1comprises a torque sensor62interposed between the shaft of the pedal cranks10and the second transmission shaft20and is configured to detect the pedal torque applied by the cyclist while pedalling.

Advantageously, the torque sensor62is connected to the electric assist motor60, for example by a control unit (not shown), so as to activate the same electric assist motor60as a function of the detected pedal torque value applied by the cyclist.

In other words, according to a possible aspect of the invention, the activation and adjustment of the assist motor torque value provided occurs when the torque sensor62detects that the pedal torque of the cyclist exceeds a predetermined value. Therefore, beyond such a predetermined value, the electric assist motor60is activated to assist the rider, while below such a value it is deactivated.

According to an aspect of the invention, the torque sensor62comprises a rigid portion connected to the cover casing of the device for changing the transmission ratio and a deformable portion connected to the second transmission shaft20. Both portions comprise sensors, for example strain gauges, associated with each other and configured to constantly detect the mutual distance thereof. The pedalling of the cyclist is such as to induce a distancing movement between the main gear wheel14and the inlet pinion24. Such a distancing causes a geometric deformation of the deformable portion of the torque sensor62such that the distance between the sensors changes. Thus, the torque sensor62is configured to detect such deformation and, by the control unit, convert it to a torque value applied by the cyclist on the pedals. Such a value is subsequently used to determine the activation and adjustment of the operation of the electric assist motor60.

According to a preferred aspect of the invention, the control unit is configured to allow the activation of the reverse gear only if the vehicle is detected as stationary.

According to another aspect of the invention, the control unit is connected to a control panel (not shown) configured to allow the cyclist to select the preferred transmission ratio, including the reverse gear ratio. The control unit is therefore connected to the micro-switch61to activate it and determine, by the movement element50, the correct positioning of the drum47in order to select the correct transmission ratio.

Advantageously, the control panel comprises a selector element, for example a button, configured to activate the electric assist motor60so as to move the transmission shafts30,20of the apparatus1and, therefore, impose the movement of the pedal vehicle100, subsequent to the configuration in the selected condition of one of the third transmission members31,32, i.e., both the transmission ratios for the forward movement of the vehicle and the reverse transmission ratio.

According to an aspect of the invention, the apparatus1is connectable to a control panel (not shown) configured to allow an operator to select the preferred transmission ratio to be used, whether to activate or deactivate the electric assist motor60. Such a control panel can comprise a lever useful for selecting the gear ratio or a simple electrical connection connected to the activation device40. Furthermore, the control panel can comprise an on or off button of the electric assist motor60and a display for displaying the selected transmission ratio.

According to a preferred aspect of the invention, the third and the second transmission members31,32,21,22comprise gear wheels engaged with each other to define the transmission ratios.

Even more preferably, the third and the second transmission member used for gear reversal32,22, between which the gear reversal member2is interposed, are arranged along the respective transmission shaft30,20and to the side with respect to the other transmission members31,21.

According to one aspect of the invention, each third and second transmission member31,32,21,22has a different radial dimension from the others. In particular, each pair formed by a third transmission member31,32engaged with a corresponding second transmission member21,22defines a different transmission ratio from the others so as to define different possible vehicle advancement speeds.

Preferably, each transmission shaft30,20comprises a plurality of respective transmission members31,21, in particular a series of gear wheels33,23arranged according to an ordered sequence along the respective longitudinal axis Z, Y.

According to a possible illustrated embodiment, the sequence of the gear wheels33,23can be ordered in ascending or descending order in terms of radial dimensions and/or number of teeth of each gear wheel.

Alternatively, the sequence of the gear wheels33,23can be ordered along the respective longitudinal axis Z, Y so as to define a double cone or similar geometric figures or other figures still not expressly identified herein.

According to a preferred aspect of the invention, the plurality of third transmission members31and second transmission members21comprise the same number of transmission members so as to determine an equal number of transmission ratios.

In other words, the number of gear wheels33of the series of the third transmission shaft30is equal to the number of gear wheels23of the series of the second transmission shaft20.

Preferably, the number of gear wheels33,23of each series is between a minimum of two wheels and a maximum of twenty wheels, even more preferably, the number of gear wheels33,23of each series is equal to ten gear wheels.

Thus, the number of achievable transmission ratios is equal to the number of gear wheels33,23of the respective series.

Preferably, the ordered sequence of gear wheels33of the third transmission shaft30is subordinate to the ordered sequence of gear wheels23of the second transmission shaft20, or vice versa. In particular, the ordered sequence of gear wheels33is achieved in a decreasing or increasing manner in terms of the size and/or number of teeth of each gear wheel23, or vice versa.

In other words, with reference to respective ends of the same side of the third transmission shaft30and of the second transmission shaft20, if the series of gear wheels33of the third is of increasing type, the series of gear wheels23of the second associated therewith is of decreasing type.

Alternatively, the sequence of gear wheels33may not be counter-shaped to the sequence of gear wheels23and have its own shape, but at least part of the gear wheels33are engaged with the gear wheels23.

According to a preferred aspect of the invention, the shaft of the pedal cranks10and the third transmission shaft30are coaxial with each other and, consequently, the shaft of the pedal cranks X and the third longitudinal axis Z coincide with each other.

Preferably, the shaft of the pedal cranks10is inserted within the third transmission shaft30as the latter has a greater cross-section than that of the shaft of the pedal cranks10. Thus, at least the third transmission shaft30is made hollow. Thereby, the third transmission members31,32are arranged along the side surface of the third transmission shaft30, while the main gear wheel14and the pedal cranks4are connected to the side ends11of the shaft of the pedal cranks10, which are protruding with respect to the third transmission shaft30. Accordingly, the main gear wheel14and the inlet pinion24are arranged to the side of the first and the second transmission members31,32,21,22, respectively.

According to one aspect of the invention, the third transmission shaft30comprises a cogged crown34splined to rotate integrally with the same third transmission shaft30. In particular, the cogged crown34is arranged to the side of the first transmission members, preferably opposite the main gear wheel14of the shaft of the pedal cranks10.

Preferably, the cogged crown34can be a gear wheel adapted to engage with a toothed belt or a transmission chain7, in particular a bicycle transmission chain7, as seen inFIG.11, directed to the drive wheel5of the bicycle.

According to an aspect of the invention, the tertiary gear wheel25coincides with one of the second transmission members21,22of the second transmission shaft20.

Advantageously, each second transmission member21,22is integral with the second transmission shaft20and, therefore, the action of the electric assist motor60on any of such second transmission members21,22is such as to rotate the entire second transmission shaft20and the third transmission members31,32, but not the third transmission shaft30and the shaft of the pedal cranks10, unless one of the third transmission members is configured in the selected condition. When one of the third transmission members31,32is in the selected condition, only the third transmission shaft30is integral therewith and, consequently rotating, while the shaft of the pedal cranks10, given the presence of a free wheel at the main gear wheel14, is independent in movement with respect to the action induced by the electric assist motor60.

As illustrated inFIG.11, the invention also relates to a pedal vehicle100comprising the apparatus1for gear reversal described above.

According to an aspect of the invention, the pedal vehicle100may be a bicycle or a cargo-bike comprising a pair of pedal cranks4each of which is connected to a respective end of the shaft of the pedal cranks10and a drive wheel5having an outlet pinion6splined and associated by a fixed snap connection with the third transmission shaft30so as to rotate integrally with the same third transmission shaft30both according to a main travel direction and according to an inverted travel direction.

In other words, there is no free wheel on the drive wheel5of the pedal vehicle100, since one or more free wheels are arranged inside the apparatus1to allow a free counter-pedalling movement by the cyclist without this generating a blocking of the transmission and, therefore, of the rotation of the drive wheel5.

InFIG.11, the outlet pinion6is directly connected to the cogged crown34of the third transmission shaft30by a transmission chain7.

If the pedal vehicle100is a cargo-bike, it has a pair of rear drive wheels5and also a loading area, front or rear, in which the objects to be transported are housable.

Therefore, the cargo-bike is a bulky vehicle with more difficult maneuverability than a normal bicycle.

Therefore, the arrangement of an apparatus1for gear reversal is advantageously able to allow the cyclist to move the cargo-bike with considerably less effort if, for example, it has a heavy load, it is on a sloping road or it is blocked in a narrow road in which it is impossible to use steering to reverse directions.