Technical field

The present description relates to a traction device that can be applied to a touring ski to reduce the user's effort on climbing. The present description also relates to a ski provided with this traction device.

Background of the description

DE202012101242 U1 and IT20181000006186 describe traction devices for touring skis, which comprise a frame that can be mounted on a ski and is equipped with at least one electric motor suitable of rotating a pair of tracks arranged on both sides of the frame, and therefore of the ski, to help the user to climb a mountain with the skis.

Said known devices are provided with sensors for controlling the movement of the tracks. In particular, DE202012101242 U1 describes sensors for detecting the acceleration and inclination of the ski, while IT20181000006186 describes motion and force sensors such as speed sensors, accelerometers or gyroscopes. Said known devices are relatively expensive, bulky and unreliable, above all due to their mechanical structure and the type of sensors used, which only follow the movement of the ski in space to control the electric motor.

DE102015014871 A1 describes a traction device integrated in a ski and provided with force and position sensors arranged under the ski binding. Said sensors are not suitable for detecting a forward movement of the boot applied to this binding.

ES2670353 describes a traction device for snowboards, not for skis, in particular touring skis, which does not comprise sensors suitable for detecting movements of the boots with respect to the snowboard.

Summary of the description Object of the present description is therefore to provide a traction device free from such drawbacks. Said object is achieved with a device and a ski, the main characteristics of which are specified in the attached claims, to be considered an integral part of the present description.

Thanks to the particular mutual arrangement of frame, sensor and track, the traction device is relatively compact and allows to detect the movement of the boot with respect to the ski, in order to control the electric motor that drives the track in a simpler and more precise way, reducing thus the cost of manufacturing the device and increasing its reliability.

Furthermore, the particular structure of the frame allows to arrange the track next to the user's boot, even only on the outer side of the ski, in order to bring the traction of the track closer to the center of gravity of the ski, thus improving its directionality, and avoid the presence of tracks on the inner side of the ski, thus improving its handling.

The sensor is preferably a microswitch, so as to further simplify the device and increase its reliability, especially in extreme situations such as those of ski touring.

The traction device is preferably provided with a particular support to be fixed to the ski, which allows an easy application or separation of the device to the ski.

Brief description of the drawings

Further advantages and characteristics of the traction device according to the present description will become evident to those skilled in the art from the following detailed description of some embodiments, to be considered non-limiting examples of the claims, with reference to the attached drawings wherein: figure 1 shows a side view of a first embodiment of the device applied to a ski; figure 2 shows a top view of the device of figure 1 ; figures 3 and 4 show enlarged sectional views of the support of the device of figure 1 ; figure 5 is an electrical diagram of the device of figure 1 ; figure 6 shows the device of figure 1 during an activation step; figure 7 shows a side view of a second embodiment of the device applied to a ski; figure 8 shows a top view of the device of figure 7.

Exemplary embodiments

Figures 1 to 4 show an embodiment of the traction device, which comprises at least one frame 1 , in particular a substantially rectangular plate with an upper edge bent to form an angle of approximately 90° with the rest of the plate. The frame 1 is adapted to be preferably fixed on the outer side of a ski 2 by means of fastening means, preferably removable, in particular by means of at least one bracket 3, for example an angular plate. The bracket 3 is integral with the frame 1 , for example fixed to the frame 1 by means of a plurality of screws 4, while it is joined to the ski 2 preferably in a removable way, in particular by means of a support 5 fixed to the ski 2, for example by means of a plurality of screws 6 inserted in holes 7 obtained in the support 5, so that the heads of the screws 6 are housed in the support 5, while the stems of the screws 6 are screwed into the ski 2. In an alternative embodiment, the bracket 3 is made in a single piece with the frame 1 , for example by shaping the lower part of the plate.

The support 5 has a seat 8 suitable to contain a portion of the bracket 3 and a block 9 suitable to stop the bracket 3 in the seat 8. Preferably, the support 5 and the seat 8 have substantially parallelepiped shapes with longitudinal axes parallel to each other.

The block 9 can move with respect to the support 5, in particular by rotating around a pin 10 substantially parallel to the longitudinal axis of the support 5, in the direction of figures 3 and 4, between a locked position, shown in the figures, and an unlocked position, shown with dashed lines in the same figures. The block 9 is provided with a tooth 11 suitable to protrude into the seat 8 and to enter an opening 12 in the bracket 3 to prevent movement of the bracket 3 into the seat 8 in the locked position of the support 5. The block 9 can be provided with an external opening 13 adapted to be engaged by the tip 14 of a ski pole to operate the block 9, in particular to move it to the unlocked position of the support 5, preferably by overcoming the action of one or more spring plungers 15 arranged in the block 9 and protruding into the cavity of the support 8, or vice versa, to keep the block 9 in the locked position.

The support 5 is preferably fixed between the toe piece 16 and the heel piece 17 of a ski binding fixed to the ski 2, so that during use the boot 18 applied to the ski binding is arranged above the support 5 and the frame 1 is arranged beside the boot 18, namely beside the space between the toe piece 16 and the heel piece 17. For this purpose, the height of the support 5 is less than the height of the plates which lift the boot 18 from the ski 2.

The frame 1 supports at least one electric motor 19, in particular a 24 V motor with a current absorption of up to 20 A, which is provided with a reducer 20 with worm screw to drive at least one drive wheel 21 with a torque of up to at least 7 Nm and/or with an angular speed up to at least 350 rpm. The electric motor 19 and the reducer 20 are fixed directly to the frame 1 but in alternative embodiments they can be fixed to the frame 1 by means of connecting elements. The drive wheel 21 and one or more driven wheels 22 can be fixed directly or indirectly to the frame 1 in a rotatable manner. In particular, the frame 1 is provided with one or more suspensions 23 which can rotate with respect to the frame 1 and rotatably support one or more driven wheels 22. The drive wheel 21 and/or the driven wheels 22 are preferably provided with suitable ratchets to allow their rotation in one direction and to prevent it in the opposite direction.

At least one track 24 is arranged around the drive wheel 21 and/or the driven wheels 22 to be driven by the drive wheel 21 . One or more protrusions 25, in particular metal fins, are attached to the outside of the track 24.

A sensor 26 suitable to control the electric motor 19 is arranged on the frame 1 on the opposite side of the track 24, namely on the same side as the bracket 3, so that the sensor 26 is arranged in a position adjacent to the position of the boot 18 during the use. The sensor 26 is preferably fixed in an adjustable manner to the frame 1 by means of a bracket 27 which can be moved in at least one direction, in particular in height, with respect to the frame 1 and/or the sensor 26, so that the sensor 26 can be arranged in a suitable position for detecting movements of the boot 18 with respect to the ski 2. In particular, the sensor 26 is a microswitch provided with a lever that can be pressed by the boot 18 to open the circuit of the microswitch when the boot 18 rests on the ski 2 and can be released by elastic means, thus closing the circuit of the microswitch, when the boot 18 rises from the ski 2. Alternative embodiments of the device can comprise different types of sensor, for example a magnetic sensor which detects a magnet placed on the boot 18.

The electric motor 19 is connected through at least one electric line to the sensor 26. The electric motor 19 and/or the sensor 26 are in turn connected to one or more cables 32 through at least one connector 28 fixed to the frame 1 , in particular on the part upper part of the electric motor 19, which is mounted on the frame 1 in a vertical position to project upwards.

Figure 5 shows the electric motor 19, the sensor 26, the cables 32 and the connector 28, which in turn is connected to at least an electronic control unit 29 connected by further electric cables and at least one connector 30 to at least one source of electric energy, in particular a 24 V battery 31 , which can power the electric motor 19. The control unit 29 and the battery 31 can be arranged in a backpack carried by the user. A further electric motor 19 of a further traction device similar or equal to the one described above can be connected to the electronic control unit 29 by means of cables 32, a connector 28 and a further sensor 26, which is arranged near another boot of the user. Said further traction device is fixed on a second ski of the user so that both skis are provided with a traction device arranged on the outer side of each ski.

The electronic control unit 29 is preferably provided with a microprocessor, a potentiometer and/or input/output means, for example lights, displays, buttons and/or a Bluetooth interface for control via smartphone, to turn on or off the traction devices, adjust the speed of the electric motors 19 and/or check the state of charge of the battery 31 . Figure 6 shows the traction device during its activation, when the sensor 26 does not detect the presence of the boot 18 when the heel piece 17 is unlocked, so that the boot 18 can rotate forward with respect to the ski 2. With this rotation forwards, the boot 18 is raised with respect to the ski 2 and is held thereto only by the toe piece 16 during the ascent and thrust phase of the ski. Therefore, with this movement of the boot 18, the sensor 26 activates the electric motor 19, which drives the track 24 through the reducer 20 and the drive wheel 21 , thus thrusting the ski 2 and accompanying the movement of the user's foot.

Figures 7 and 8 show a second embodiment of the traction device, which is similar to the first embodiment in that it comprises at least one frame 1 which supports at least one electric motor 19 suitable to drive at least one drive wheel 21 which is rotatably fixed directly or indirectly to the frame 1 , at least one track 24 adapted to be driven by the drive wheel 21 , and at least one sensor 26 adapted to control the electric motor 19 according to the movements of the boot 18 with respect to the ski 2. The track 24 can comprise one or more protuberances 25 and can be supported by at least one driven wheel and/or by at least one further drive wheel 21 ' connected to the electric motor 19 by means of a mechanical transmission arranged in the frame 1 , or, in an alternative embodiment not shown in the figures, to a further electric motor fixed to the frame 1 close to this further driving wheel 21 '. The control unit 29, a potentiometer 33 for manual adjustment of the electric motor 19 and/or the battery 31 can be fixed to the frame 1 or to the electric motor 19. The battery 31 is preferably arranged in a space surrounded by the track 24. A further battery can be connected to the connector 28. The bracket 3 can be fixed in a removable manner by means of screws 6, preferably between the toe piece 16 and the heel piece 17, directly to the ski 2 or, indirectly, to an element integral with the ski 2, for example a plate. The electric motor 19 is preferably fixed to the frame 1 so that the rotation axis of the electric motor 19 is substantially perpendicular to the rotation axis of the drive wheel 21. As in the first embodiment, the frame 1 is arranged beside and not above the ski 2. The frame 1 can be made in a single piece or comprise several elements joined together.

Variations or additions can be made by those skilled in the art to the embodiments described and illustrated here while remaining within the scope of the following claims. In particular, further embodiments may comprise the technical characteristics of one of the following claims with the addition of one or more technical characteristics described in the text or illustrated in the drawings, taken individually or in any reciprocal combination.