Patent Application
20090212534
This application claims priority under 35 U.S.C. §119 of French Patent Application No. 08 01040, filed on Feb. 26, 2008, the disclosure of which is hereby incorporated by reference thereto in its entirety.
1. Field of the Invention
The invention relates to a gliding apparatus equipped with a release device for a device for binding a boot on the gliding apparatus.
The invention relates in particular to a release device for a device for binding a boot on a gliding board comprising a rotatable electromagnetic motor, or the like.
In particular, the present invention relates to a device for binding a boot on a ski comprising a releasable front retaining element and a releasable rear retaining element, and further comprising additional electronically-controlled means for opening the binding, these additional opening means being equipped with a release device.
2. Background Information
The document WO 95/12440 discloses a device that includes a releasable front retaining element, a releasable rear retaining element, and additional opening mechanism. The front and rear retaining elements are conventional mechanical binding elements for a ski boot, namely, a front/toe piece element and a rear/heel piece element, which release the boot from its ski when the boot is subjected to loads beyond a given threshold. The load threshold corresponds to the prestress value to which springs positioned in the toe and the heel pieces are subjected.
The additional opening mechanisms are constituted by an electronically-controlled latch, which releases the boot by allowing the free translation of the heel along a slide rail. The latch is actuated by means of a vertical translational movement. In the normal resting position, the latch is maintained in a low position by the force of a spring, whereas movement to the high position is caused by the pressurizing of an annular chamber surrounding the latch.
When skiing, but also under other conditions, the impacts to which the gliding apparatuses, i.e., the skis and the bindings, are subjected can be very substantial. For example, impacts occur during skiing, i.e., when landing from jumps or passing over bumps, e.g., and they occur when the equipment drops while in storage, or even when laying the equipment on the ground. Given that the mechanism controlling the release, i.e., the latch, is actuated with a translational movement, such movement can be unintended and, in certain cases, such movement can generate an undesirable ill-timed release of the boot.
The invention provides a release device for a device for binding a boot on a gliding board, which operates in a more stable fashion than prior art devices, and in particular a release device which prevents ill-timed releases.
In addition, the invention provides a release device for a device for binding a boot on a gliding board, which is less expensive to manufacture.
Further, the invention provides a release device for a device for binding a boot on a gliding board, which is more compact than existing prior art devices in order to allow for better integration into the ski and into the system of the boot binding device.
Further still, the invention provides a release device for a device for binding a boot on a gliding board comprising a rotatable electromagnetic motor that consumes less electricity.
According to a particular embodiment, the invention encompasses a release device for a device for binding a boot on a gliding board that includes a rotatable electromagnetic motor, having an axis A1, on the output shaft of which a cam is fixed; a lever pivoting about an axis A2, between a closed position and an open position, and having a large crank in contact with the cam and a small crank; a release mechanism (or “trigger”) that includes at least one control tooth, which is in contact with the small crank when the lever is in the closed position, and at least one release tooth; a rod capable of assuming a closed position and an open position, the rod being provided, at one of its ends, with a notch in which the release tooth is engaged when the rod is in the closed position.
In such embodiment, the rod is connected by its other end to the boot retaining element, which is capable of moving away therefrom, thus releasing and freeing the boot.
In a particular arrangement of the invention, there are a pivoting lever and a tripper between the motor which controls the tripper and the rod which does carry it out. This enables a reduction between the force necessary to free the rod and the maximum torque the motor can provide, without the need for gear trains. This contributes considerably to reducing the current consumption.
The invention can employ a motor that can deliver a maximum torque of less than 2 mN·m (milliNewton·meter), or even less than 1 mN·m, on the output shaft.
The use of a motor having a maximum output torque of less than 2 mN·m lowers the manufacturing costs as well as reduces the volume of the complete device, due to a greater ease of integration. This is all the more true when a motor is employed whose maximum torque is less than 1 mN·m.
Advantageously, the electromagnetic motor is in direct engagement, i.e., there is no gear train between the motor and the cam.
Advantageously, a drive finger is arranged at the end of the large crank, this drive finger being in contact with the cam surface.
Advantageously, in the embodiment being described here, the cam includes a plate on which a cam groove is provided, and this cam groove includes at least two distinct and contiguous portions, i.e., referred to as the initial ramp and the release ramp, the initial ramp being in the form of an arc whose variation in radius at the axis A1 is less than 20%, as small as zero in a particular embodiment, and occupying an angular sector greater than 90°.
Advantageously, the initial ramp corresponds to a path of the drive finger between a point C1 and a point C2, the points C1 and C2 being positioned, or substantially positioned, at the same distance from the axis A1.
Advantageously, the initial ramp corresponds to a path of the drive finger substantially forming an angular arc having an angle α1, centered on the axis A1, and having a radius Rmin.
As long as the drive finger is in the initial ramp of the cam groove, and given that this initial ramp has a quasi-constant radius, or even a constant radius, the finger exerts on the cam only a torque that is close to zero. Consequently, during the entire time the motor carries out the rotation through angle α1, the torque delivered by the motor is used only to overcome its own inertia.
The motor selected is miniaturized, and its electricity consumption is reduced as much as possible. It has a high rotation speed and only delivers a very low torque, on the order of 1 mN·m. This is not a limiting characteristic of the invention, and motors capable of delivering a torque greater than 2 mN·m can be used.
In the release device according to the invention, the torque required from the motor is directly proportional to the force of the drive finger on the cam, but also to the radius to which the latter is applied. Therefore, an initial ramp with a very small radius is advantageous in order to have a low torque at the start.
The torque C that the motor must exert in order to move the cam, which is subjected to the force exerted by the drive finger, is given by the following formula:
C=F
finger
×tgφ×R
ramp
where Ffinger is the force exerted by the drive finger on the cam, φ is the coefficient of friction, and Rramp is the radius of the ramp at the location considered. Advantageously, the initial ramp, which corresponds to the start of the motor, is the smallest possible. In practice, the radius of the initial ramp is equal to the sum of the radius of the drive finger and of the functional clearance.
Advantageously, the release ramp corresponds to a path of the drive finger between the point C2, positioned at a distance Rmin from the axis A1, and a point C3, positioned at a distance Rmax from the axis A1 and occupying, in relation to the axis A1, an angular sector having an angle α2.
Advantageously, the plate includes a third portion, referred to as the final ramp, which is in the form of an arc whose variation in radius at the axis A1 is less than 20%, as small as zero in a particular embodiment, this final ramp being contiguous with the release ramp.
Advantageously, the final ramp corresponds to a path of the drive finger substantially forming an angular arc having an angle α3, centered on the axis A1, and having a radius Rmax.
Similar to what occurs when the finger is in contact with the initial ramp, when the latter is in contact with the final ramp, it does not exert any force on the cam. The motor then no longer has any torque to exert, and its consumption, which is proportional to the electric current that runs through it, is reduced. It is possible to determine the operational limit of the motor, without installing a sensor, but by monitoring the electricity consumption.
Advantageously, the length L1 of the large crank is greater than 2 times the length L2 of the small crank; in a particular embodiment of the invention, the length L1 is greater than 2.7 times the length L2.
Advantageously, the distance D1 separating the control tooth from the axis A3 is greater than three times the distance D2 separating the release tooth from the axis A3, and 3.7 times greater in a particular embodiment.
Because a high reduction ratio is desired, and in view of the space available, the ratios alone between the lever arms are not sufficient. This is why the particular arrangement of the lever and of the retaining rocker provides judiciously selected slopes for the contact surfaces between the lever, the tripper, and the rod.
Advantageously, the tripper pivot connection having an axis A3 is ensured by two pins received in connecting bearings that have a radius R52, and the slope of the tripper contact surface that comes in contact with the rod is determined such that the direction of the rod contact force on the tripper, which is determined in relation to the normal at the “rod/tripper” contact point by taking into account the coefficient of friction φ2, is outside of the circle K1, having an axis A3 and a radius R1, R1=R52×Sin φ1, where φ1 is the coefficient of friction existing between the pins and the connecting bearings.
The direction of the rod contact force on the tripper does not intersect with the circle K1.
Advantageously, the lever pivot connection having an axis A2 is ensured by a first pin received in a bearing that has a radius R50, and the slope of the tripper contact surface that comes in contact with the lever is determined such that the direction of the lever contact force on the tripper, which is determined in relation to the normal at the “lever/tripper” contact point by taking into account the coefficient of friction φ4, is outside of the circle K2, having an axis A2 and a radius R2, where R2=R52×Sin φ3, and where φ3 is the coefficient of friction existing between the pin and the bearing that receives it.
Due to this arrangement of the lever and of the rocker, a reduction is obtained such that the rod, while in the closed position, is subjected to a force of approximately 120 daN; the tripper being controlled by a motor delivering a torque of about 1 mN·m.
The device according to the invention enables a reduction ratio higher than 50 and, in a particular embodiment, as much as higher than 100.
In one embodiment of the invention, the axis A2 and the axis A3 are perpendicular.
In another embodiment of the invention, the axis A2 and the axis A3 are substantially parallel.
In a particular embodiment of the invention, the release device further includes a locking mechanism, which prevents the release tooth from disengaging from the notch, the locking mechanism being capable of being alternatively in the unlocked position or the locked position.
Advantageously, the locking mechanism includes a pawl on which is arranged a first stop which, when the locking mechanism is in the locked position, comes in contact with a locking tooth arranged on the tripper in order to prevent the rotation thereof in the release direction.
Advantageously, the pawl is rotationally mounted about an axis A4, and it includes a second stop, which is maintained in contact with a bolt by means of a latch spring.
The invention can be better understood upon reading the description that follows, with reference to the annexed drawings, and in which:
The toe piece 2 is a conventional front binding with mechanical release, i.e., it releases when the loads to which it is subjected are greater than the prestress value of a first spring positioned in the toe piece 2.
The heel piece 3 is a conventional rear binding with mechanical release, i.e., it releases when the loads to which it is subjected are greater than the prestress value of a second spring positioned in the heel piece.
The front interface 5 and/or rear interface 6 can be integrated into the toe piece 2 and/or the heel piece 3, respectively, or even integrated into the ski 1. However, as is the case in the embodiment shown, the front interface 5 and rear interface 6 are independent parts that are fixed on the ski, and on which the toe piece 2 and the heel piece 3 are fixed.
In the configuration described here, when the skier's leg is subjected to forces directed in the horizontal plane of the ski, including torsional forces around a vertical axis, it is the toe piece 2 that releases and frees the boot. When the skier's leg is subjected to forces directed in a vertical plane, it is the heel piece that releases.
This configuration is not limiting, and any configuration of retaining element with mechanical release is encompassed by the invention.
The front retaining element, namely the toe piece 2, includes a slide rail in which the body of the front retaining element can slide. It is the sliding motion of the toe piece 2 in the slide rail that constitutes the supplemental release. The supplemental release is controlled by the release device 4 according to the invention.
Reference is made here to a supplemental release insofar as this release is added to the two conventional releases known in the field of alpine skiing, i.e., the release of the toe piece 2 and the release of the heel piece 3.
Whereas the release of the toe piece 2 and the release of the heel piece 3 are strictly mechanical, the supplemental release, controlled by the release device according to the invention, is an electronically-controlled release. The control of the supplemental device by electronic means offers a number of advantages over the mechanical release. For example, a release can be provided, which is dependent upon the duration of the forces being applied to the user's leg. See, for example, U.S. Pat. No. 7,438,307 and U.S. Patent Application Publication No. 2008/0197607, the disclosures of which are hereby incorporated by reference thereto in their entireties. A release can also be provided that is controlled directly by the user, such as, for example, by means of a button positioned on the handle of the ski pole, or on the ski itself.
The device of the invention is not limited to being used as a release device, which generates a supplemental release added to the releases of the front and rear retaining elements. Indeed, the device according to the invention can be used as a single release, which can be associated, for example, with non-releasable front and rear retaining elements such as stirrups or clamps. See, e.g., the aforementioned U.S. Patent Application Publication No. 2008/0197607.
The release device 4 according to the invention includes a housing 8 positioned on the ski, between the front interface 5 and the rear interface 6.
As shown in
The release device 4 according to the invention also includes two bars 13 fixed on the housing by means of plates 14, and on which the force sensors 43 (see
For reasons of simplification in explaining the operation of the release device 4,
The motor 9 is not shown in
The lever 12 is pivotally mounted about an axis A2, shown in the drawing by a fine dotted line, and is embodied by a first pin 50. The lever 12 includes a large crank 20, at the end of which the drive finger 35 is located, as well as a small crank 21, at the end of which the retaining finger 22 is located. The drive finger 35 is made from a wire which is forcibly inserted, i.e., frictionally maintained, in a cylindrical cavity of the lever, and which projects from the lever by a distance such that it can penetrate in the groove 19 of the cam 11. The retaining finger 22, which is subjected to greater forces than the drive finger 35, also comprises a wire forcibly inserted in a circular cavity of the lever 12, but it also includes a protuberance 57 of the lever which is used to support the wire. The wires used are spring strands, for example. They allow for very high local support pressures.
The lever can also be made as a unitary element.
The lever 12 is shown in
The tripper 10 is pivotally mounted about an axis A3, which is perpendicular to the axes A1 and A2. It includes a release tooth 25 provided to be fitted in a notch 28 arranged at one of the ends of the rod 27.
The other end of the rod 27 is not shown in this drawing figure. The other end is connected to the retaining element of the boot, which is capable of moving away in order to release and free the boot. In the example shown here, the retaining element adapted to move away is the toe piece 2. The release device also includes a locking mechanism 53. The locking mechanism 53 has the function of maintaining the release device 4 in the closed state. Thus, irrespective of the conditions measured by the sensor, the tripper 10 cannot pivot and, consequently, cannot release the rod 27. Reference is here made to U.S. Patent Application Publication Nos. 2007/0170695 and 2007/0170696, the disclosures of which are hereby incorporated by reference thereto in their entireties.
Such a locking mechanism is particularly advantageous because if the electrical energy feeding the control electronic circuit were to be lacking, or if the electronic circuit were to fail, there would be a risk of ill-timed release. Thus, the locking mechanism 53 makes it possible to re-engage the release device 4 if the power supply were to be lacking while the device is in the open position. Furthermore, when carrying out the procedures for testing the functioning of the mechanical releases of the binding device, i.e., of the heel and toe pieces, in order to verify compliance with the standards, or during long term storage, it is important to switch off the supplemental release, in order not to disturb the verification of standards compliance.
The locking mechanism 53 includes a bolt 32 on which a cam bolt 33 is arranged; this bolt is actuated by a handle 33 and acts on the tripper 10 by means of a pawl 16. The pawl 16 is pivotally mounted about an axis A4 defined by the second pin 51. The pawl 16 includes a first stop 29 adapted to come in contact with a locking tooth 25 arranged on the tripper 10. It also includes a second stop 30, an anchoring structure 55 intended for connecting a latch spring 31, and arranged on the opposite pawl 16, in relation to the axis A4 of the second stop 30. Thus, the spring which works in compression maintains the second stop 30 in contact against the cam bolt 34 of the bolt 32.
The cam bolt 34 mainly includes two portions, namely a “locking” portion and an “unlocking” portion.
A user's action on the handle 33, causing it to make a half-turn, causes the bolt 32 to rotate by a half-turn. It is then the “unlocking” portion of the cam bolt 34 which is opposite the second stop 30. The latch spring 31 ensures that the contact between the second stop 30 and the cam portion is properly maintained. In this position of the pawl 16, the first stop 29 is no longer opposite the locking tooth 26. Thus, the pawl does not prevent the rotation of the tripper 10 in the direction S, referred to as the release direction.
The release device 4 of
The main plate 36 supports the electronic components of the release device 4. These include a printed circuit, an input/output device, which is connected to the acquisition/visualization module.
The main plate 36 is connected to the motor 9 by means of a motor cable 39. The main plate 36 is also connected to the sensor 43 arranged on the bar 13. The main plate 36 is also connected to a limit plate 37 located in the vicinity of the locking mechanism 53 and the tripper 10.
The limit plate 37 includes a limit sensor 59 of the tripper 10, positioned in correspondence with the fin 40 of the tripper, and a limit sensor 60 of the pawl, positioned in correspondence with the fin 41 of the pawl. The limit sensors enable the electronic device to constantly know the position of the tripper 10 and pawl 16. The sensor 43 positioned on the bar 13 informs the electronic components of the release device 4 about the forces to which the boot and the user's leg, are subjected.
The initial ramp 44 corresponds to the path followed by the drive finger 35, from its resting position, defined by the point C1 in
This arc of circle C1-C2 defines an angular sector having an angle α1 that is substantially equal to 130°.
Due to this configuration of the initial ramp 44 in the first rotational phase of the motor 9, the drive finger 35 exerts a torque close to zero on the motor axis. Indeed, this first rotational phase of the motor is carried out with a constant radius for the position of the drive finger 35 on the cam. Consequently, during this phase, the torque delivered by the motor is used only to overcome its own inertia.
Advantageously, the radius Rmin of the initial ramp is very small, in particular smaller than 2 mm (millimeters).
The invention also encompasses the initial ramp 44 not being made with a constant radius, but rather with a radius that varies very slightly, for example a radius whose variation between C1 and C2 does not exceed 20%.
The second portion of the cam pathway 18 is the ramp 45. This release ramp corresponds to a path of the drive finger 35 between the point C2, positioned at a distance Rmin from the axis A1, and a point C3, positioned at a distance Rmax from the axis A1. The release ramp 45 occupies, in relation to the axis A1, an angular sector having an angle α2.
When the drive finger 35 goes from the point C2 to the point C3, the lever 12 rocks from the closed position (as shown in
In the first, the locking mechanism is in the “locking” position (as shown in
The second possibility corresponds to the normal functioning of the release device. The unlocking device is in the unlocking position, and the pawl 16 does not prevent the tripper from turning in the release direction S. When there is no more contact between the retaining finger 22 and the control tooth 24, the tripper 10, pushed by the spring leaf 23, is driven in the release direction S, the release tooth 25 exits from the notch 28 and the rod 27 is released. The sliding of the rod 27 causes that of the toe piece 2, which results in freeing the boot.
The third portion of the cam groove 18 is referred to as the final ramp 46. It corresponds to a path of the drive finger 35 between the point C3 and the point C4. This is an arc of circle or a straight line having a constant or quasi-constant radius with respect to the axis A1. It occupies an angular sector having an angle α3 substantially equal to 10°. When the drive finger 35 is in the final ramp, it no longer exerts any force on the cam 11, so that the motor no longer has to deliver a substantial torque. Given that the torque delivered by an electromagnetic motor is proportional to the current which it consumes, monitoring its electricity consumption makes it possible to know at which moment the drive finger 35 reaches its final position and, consequently, at which moment it is necessary to stop supplying the motor 9.
The motor 9 is a rotatable electromagnetic motor, or the like, which outputs a low torque of about 1 mN·m. The release device does not comprise any gear train on the output shaft of the motor, but it is known that gear trains consume energy. The reduction in the forces is obtained by a particular arrangement of the lever 12 and of the tripper 10.
The particular arrangement of the lever 12 and of the tripper 10 includes in particular the shape of each of these two parts, the distances which separate the contact points and the axes of rotation A2 and A3, and the slopes of the contact surfaces between the various parts.
The length L1 of the large crank is greater than 2 times the length L2 of the small crank, and greater than 2.7 times in a particular embodiment. In the example described, the L1/L2 ratio is equal to 3.
The distance D1 separating the control tooth from the axis A3 is greater than three times the distance D2 separating the release tooth from the axis A3, and greater than 3.7 times in a particular embodiment. In the example described, the D1/D2 ratio is equal to 5.
Furthermore, the orientation of the contact surfaces between the parts contributes to the reduction in the forces. This is particularly the case in the area of the rod/tripper and tripper/lever connections.
To determine this slope, the friction in the pivot connection of the tripper with respect to the housing 8 and to the lid 7 is taken into account. This pivot connection is ensured by two pins 52 that are received in connecting bearings arranged in the housing and the lid. These bearings have a radius R52.
The friction in the pivot connection is graphically represented by a circle K1 having a radius R1=R52×Sin φ1, where φ1 is the coefficient of friction in the pivot connection between the tripper 10 and the connecting bearings 61.
The slope of the rod/tripper contact is then determined by taking into account the coefficient of friction φ2 between these two parts. The direction of the contact force of the rod on the tripper is determined in relation to the normal at the “rod/tripper” contact point 65. In order not to create a jamming of the system and a blocking thereof, one must ensure that the direction of the contact force 65 remains above the circle K1.
Similarly, the lever 12 must tend to rock when the tripper wants to turn.
The lever 12 is pivotally mounted by means of a first pin 50 having a radius R50. Taking into account the friction in the pivot connection created by this first pin 50, it is represented by a circle K2 having a radius R2=R50×Sin φ3, where φ3 is the coefficient of friction in the pivot connection.
The direction of the contact force 66 between the tripper 10 and the lever 12 is determined with respect to the normal at the “tripper/lever” contact point 67 by taking into account the coefficient of friction φ4 of the tripper 10 on the lever 12.
The slope of the second contact surface 63 is then determined so that the direction of the contact force 66 remains out of the circle K2.
In view of the size of the system, the available energy, and the release speed, a small and low torque motor is used. Therefore, the force required for unlocking the system must be very low.
Consequently, it is imperative to know the coefficients of friction for each connection as well as possible in order to optimize the geometries of the friction surfaces between the various parts; a compromise between jamming and the transmitted force.
Due to this particular arrangement of the lever and of the rocker, a reduction is obtained such that the rod, while in the closed position, is subjected to a force of approximately 120 daN; the release is controlled by a motor delivering a torque of 0.5 mN·m.
The use and the operation of the release device according to the invention will now be explained.
Initially, the user, or the technician if the user does not have adequate technical skills to adjust the bindings, takes his/her pair of skis and verifies that all of the elements necessary for his/her safety are indeed present. The first verification relates to the conventional front and rear retaining elements. To this end, the user ensures that the handle 33 of the locking mechanism 53 is indeed in the “locking” position. When the locking mechanism is in the locking position, the release device 4 is inoperative, and the user, or the technician, can adjust the heel piece 3 or the toe piece 2. These adjustments are not be described in detail as they are widely known in the prior art. It is simply noted that these adjustments include both a length adjustment and the calibration of the springs housed in the toe piece 2 and the heel piece 3.
Next, the user resets the handle 33 in the “unlocking” position by rotating it 180° about its axis. The user then uses the acquisition/visualization module 58 (see
These preliminary verifications are not always necessary if the same user uses his/her skis on several occasions.
Once the verifications have been performed, the user can put on his/her skis and can begin skiing. A plurality of exemplary cases may arise when skiing; for reasons of simplification, only three of such cases will be described.
In the first case, the user makes a quick forward fall in the direction of the skis. In this case, it is the heel piece 3 that releases and frees the boot.
In the second case, the user is subjected to a quick leg twisting. In this case, it is the toe piece 2 that releases and frees the boot.
The first two cases are conventional release situations. In any case, the release situations are resolved by the binding devices such as are currently known on the market.
In the third exemplary case, the leg twisting/or the leg forward tilting are not as fast; or yet these forces do not reach the release threshold of the toe piece 2 or of the heel piece 3, but they are applied for a period of time such that they can endanger the user. This last case often occurs during falls while at a stop.
It is in this third case in particular that the release device comes into play. The sensor 43 (see
When the release must be initiated, the signal is sent to the motor 9. The rotation of the motor and of the cam causes the lever 12 to rock until it reaches the open position. When the lever 12 has reached its open position, it no longer imposes any obstruction on the tripper 10, which can pivot in the release direction S. The rod 27 is released and, given that it is translationally connected to the toe piece 2, the forces exerted on the toe piece drive the rod 27. The toe piece 2 moves away from the heel piece and the boot is released.
In order to resume the practice, the user must reset the binding device. In the case in which the release device 4 performed a release, the reset is done by pushing the toe piece 2 in the direction of the heel piece 3. This movement also drives the rod 27 translationally towards the tripper 10, the latter still being in the open position. As soon as the end of the rod comes in contact with the tripper 10, the latter rotates in the direction opposite the release direction S. This rotation brings the release tooth 25 in the notch 28 of the rod. The electronic circuit positioned on the main plate 36 is informed of the return of the tripper 10 to its closed position, due to the limit sensor positioned on the limit plate, which cooperates with the fin 40 of the tripper. The electronic circuit can then supply the motor 9 so that it turns in the opposite direction, bringing the cam 11 back into its initial position. The cam 11 returns the lever 12 into the closed position, and the retaining finger 22 gets in contact with the control tooth 24. The release device then has returned to the closed position and reset, and the user can safely put his/her skis back on.
The initial ramp 44 corresponds to the path followed by the drive finger 35′, from its resting position, defined by the point C1 in
This arc of circle C1-C2 defines an angular sector having an angle α1 substantially equal to 130°.
Due to this configuration of the initial ramp 44 in the first rotational phase of the motor 9, the drive finger 35′ does not exert any force on the cam 11′. Indeed, this first rotational phase of the motor is done with a constant radius for the position of the drive finger 35′ on the cam. Consequently, during this phase, the torque delivered by the motor is used only to overcome its own inertia.
Advantageously, the radius Rmin of the initial ramp is very small, in particular smaller than 2 mm.
The second portion of the cam pathway 18 is the ramp 45. This release ramp corresponds to a path of the drive finger 35′ between the point C2, positioned at a distance Rmin from the axis A1, and a point C3, positioned at a distance Rmax from the axis A1. The release ramp 45 occupies, in relation to the axis A1, an angular sector having an angle α2.
When the drive finger 35′ travels from the point C2 to the point C3, the lever 12′ rocks from the closed position towards the open position. In this position, the small crank 21′ is no longer in contact with the control tooth 24′. The tripper 10′ is then free to turn in the release direction, the release tooth 25′ exits from the notch 28′, and the rod 27 is released. The sliding of the rod 27 causes that of the toe piece 2, which results in the boot being released.
The third portion of the cam pathway 18 is referred to as the final ramp 46. It corresponds to a path of the drive finger 35′ between the point C3 and the point C4. This is an arc of circle or a straight line which has a constant or almost constant radius in relation to the axis A1. It occupies an angular sector having an angle α3 substantially equal to 10°. When the drive finger 35′ is in the final ramp, it no longer exerts any force on the cam 11′, so that the motor no longer has to deliver a substantial torque. Given that the torque delivered by an electromagnetic motor 9 is proportional to the current which it consumes, monitoring its electricity consumption makes it possible to know at which moment the drive finger 35′ reaches its final position and, consequently, at which moment it is necessary to stop supplying the motor 9.
The invention is not limited to the various details and embodiments described and shown, which are presented herein by way of example, but covers all variations and equivalent embodiments.
| Number | Date | Country | Kind |
|---|---|---|---|
| 08 01040 | Feb 2008 | FR | national |
