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(11) | EP 3 199 047 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | SKI BOOT |
| (57) A ski boot 1 comprising a release element 2 for releasable attachment of the ski
boot 1 to a ski 7, the release element 2 being moveable from a first engaged position
in which the release element 2 is capable of retaining the ski 7 on the ski boot 1,
and a second released position in which the ski 7 is released from the ski boot 1,
in response to a load exceeding a threshold load applied between the ski boot 1 and
a ski 7. Control means 5 is provided for adjusting the threshold load at which the
release element 2 moves from the first position to the second position, the control
means 5 adjusting the threshold load to release the ski boot 1 from the ski 7 dependent
on the speed of the ski boot 1. A speed detector 10 is used to determine the speed
of the ski boot 1.
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[0001] This invention relates to a ski boot and particularly, but not exclusively, relates to a ski boot with a speed dependent release system that releases the ski boot from ski bindings when a predetermined release force is applied between the ski boot and the ski binding.
BACKGROUND
[0002] Conventional systems for releasing ski boots from skis provide release from ski bindings when either a large twisting force, or a large forward moment, is applied between the ski boot and the ski binding.
[0003] Conventional bindings on skis are adjustable so that the force required to release the bindings is set to be proportional to the size and weight of the skier. However, the release of the skis is only achieved reliably when the skis are travelling at high speed. This is because at high speed, if a ski is twisted or stopped abruptly, the dynamic load imparted to the binding is sufficient to release the boots from their respective bindings. By contrast at low speed, the dynamic loading may not be sufficient to fully release a ski from the boot, but the momentum of the skier can still impart severe loading to the skier's legs. The most common low speed injury to the leg results from twisting of the leg and can involve severe injury to the knee or hip and spiral fractures to one or more bones of the leg.
[0004] Other release systems are able to determine the speed of the skier, and adjust the preload on the bindings dependent on the speed of the skier or the inclination of the skis. However, these release systems require skis with a specialised binding.
[0005] It is therefore desirable to provide an improved ski release system that addresses these above described shortcomings of conventional ski release systems.
STATEMENT OF INVENTION
[0006] According to the present invention, there is provided a ski boot comprising a release element for releasable attachment of the boot to a ski, the release element being moveable from a first engaged position in which the release element is capable of retaining the ski on the boot, to a second released position in which the ski is released from the boot, in response to a load exceeding a threshold load applied between the ski boot and a ski.
[0007] The ski boot may comprise a controller which may adjust the threshold load at which the release element can move from the said first position to the said second position. The controller may adjust the threshold load to release the boot from the ski dependent on the speed of the boot, as determined by a speed detector.
[0008] The release element may be adapted to engage a binding fixed to the ski. The binding may be a conventional ski binding.
[0009] One or more release elements may be attached to the boot at any point. For example, a first release element may be attached at a heel of the boot and a second release element may be attached at a toe of the boot.
[0010] The release element may be connected to the boot by any means which allows relative movement between the release element and the rest of the boot. For example, the release element may be attached by a sliding joint, a pivot joint or ball joint.
[0011] Control over the release element may be governed by a mechanical and/or electrical system. For example, a mechanical system may comprise a modified ski binding mechanism, where the weight and size of the skier is used to set the threshold release load, and the electrical system may determine the force required to release a ski boot from its binding dependent on the speed of the skier, and then adjust the mechanical system accordingly.
[0012] The ski boot may comprise a locking mechanism for holding the release element in the first position. The locking mechanism may be switched from a locked to an unlocked condition by the controller when the threshold load is applied between the boot and the ski.
[0013] The controller may comprise an actuator to adjust the preload on the release element. The actuator may, for example, be electric, hydraulic and/or pneumatic.
[0014] The speed detector may comprise an accelerometer or speedometer and may be located in the ski boot. The speed detector may use GPS tracking to determine the motion of the skier. The speed detector may be provided in a mobile phone or other hand held device.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example to the accompanying drawings, in which:
Figure 1 is a ski boot attached to conventional ski bindings, the ski boot having a release mechanism in accordance with the present invention;
Figure 2a is a schematic view of one embodiment of the release mechanism of Figure 1;
Figure 2b is a schematic view of an actuator of the release mechanism of Figure 2a.
Figure 3a is a schematic view of another embodiment of the release mechanism, illustrating the locked position of the release element.
Figure 3b shows the release mechanism of Figure 3a with the mechanism triggered to release.
DETAILED DESCRIPTION
[0016] With reference to Figures 1 and 2, a ski boot 1 with a ski release system comprises a release element 2, a locking mechanism 4, a controller 5, a battery power supply 9, and a speed detector 10 which are all fitted within a sole of the boot 1. The power supply 9 provides DC electrical power to the locking mechanism 4, controller 5 and speed detector 10.
[0017] The release element 2 is capable of moving from a first position in which the boot is secured to a ski, to a second position in which the boot is released from the ski. In the illustrated embodiment, the release element 2 is pivotally connected to the boot at the heel of the boot, but in alternative embodiments one or more release elements (not shown) may be provided at any other position on the boot. For example, a release element may be provided at the toe of the boot in addition to, or instead of, providing a release mechanism at the heel. The release element 2 engages a binding 3 fixed to a ski 7 by means of a conventional ski boot lug 6, so that the boot can engage a conventional ski binding without requiring modification of the ski binding or the ski 7.
[0018] Referring to Figure 2A, the release element 2 is pivotally connected to the boot 1 by means of a pivot pin 8, comprising a bolt screwed into a threaded blind bore formed in the boot. The bolt is countersunk into the release element 2 so that it does not contact the ski 7 in use. In alternative embodiments, the release element 2 may be connected to the boot 1 by a sliding joint, or it may rotate around a ball and socket joint (not shown).
[0019] The controller 5 is configured to receive data indicative of the speed of the ski boot 1. In the embodiment illustrated in Figure 1, this data is generated by a speed detector 10 located within the boot 1. In alternative embodiments, the speed detector 10 may be located remotely from the boot 1, for example on the skier.
[0020] Additionally, the controller 5 may make use of existing appliances that possess the capability to calculate speed, such as a mobile phone or other hand held device capable of detecting the motion of the skier.
[0021] The speed detector 10 may comprise an accelerometer and/or a speedometer and/or a gyro speed sensor. The controller 5 may be capable of determining whether motion is due to skiing, and may make use of the speed detector 10 in order to determine this. For example, the controller 5 may be able to detect a cyclic motion of a ski boot indicative of side stepping a slope or a reciprocating motion indicative of cross country skiing.
[0022] The controller 5 varies the force at which the boot will be released from the skis in relation to the speed data that has been received by the controller 5 from the speed detector 10. The relationship between boot speed and release force is that the lower the speed, the lower the release force that is set by the controller 5. However, in alternative arrangements there may be a plurality of levels of release force, the changeover between force levels being triggered by changes in the speed of the skier. For example, when the boot is travelling at less than five miles an hour the release element may be set at a first release load. From five to twenty miles an hour it may be set at a second release load, which may be higher than the first release load, and over twenty miles an hour it may be set at a third release load, which may be greater than the second release load.
[0023] In the embodiment of Figure 2A, the controller 5 regulates the force at which the boot will be released from the skis using at least one actuator 12. The mechanism of the actuator 12 may, for example, be electric, pneumatic or hydraulic. In the embodiment of Figure 2A, actuators 12 are located on either side of an inner flange 14 of the release element 2. Plungers 13 of the actuators 12 engage the release element directly.
[0024] Referring to Figure 2B, the force at which each of the plungers 13 can be driven into the main body 15 of the respective actuator 12 is adjusted by a respective stepper motor 17 which, when energised, rotates a threaded shaft 19 engaged in a thread formed in a spring guide 21 of the main body 15. As the threaded spring guide 21 travels towards the plunger 13 it compresses a spring 23 and thereby increases the force on the plunger 13. The tension in the spring may be adjusted in this way to change the resistance to rotation of the release element 2.
[0025] At lower speeds, the tension in each spring 23 is set by the respective stepper motor 17 such that the plunger 13 can be driven into the main body 15 if a force exceeding a threshold twisting force is applied between the ski boot and the ski. The plunger 13 is only able to move a predetermined distance defined by an end stop 25 formed by the free end of the threaded shaft 19. The end stop 25 limits the amount of rotation of the release element 2. At high speeds, the tension in each spring 23 is set so that the plungers 13 are substantially fixed and the release element 2 cannot rotate. This substantially fixed state of the plungers 13 may be the default setting when the controller determines that the motion of the boot is not due to skiing, or the control system fails, for example when a battery powering the controller becomes depleted. Under these conditions, the boot 1 would behave as a regular ski boot and release of the boot 1 from a ski 7 would be dependent on the preload set on the conventional bindings 3.
[0026] In order to customize the boot to an individual skier, means may be provided to reprogram the controller 5, 105 in the boot 1, so that the threshold force at which the release element can move to the released position is changed relative to the speed of the boot. For example, if the boot is worn by an inexperienced skier, the threshold force may be set lower for a given speed, than if the boot is worn by an experienced skier. Reprogramming may be carried out remotely, for example by using an app on a mobile phone.
[0027] It is beneficial to prevent substantially all rotation of the release element 2 until a force greater than a threshold force has been applied to the ski boot. To this end, in the embodiment of Figures 3A and 3B, a solenoid 112 operates to set a lock pin 128 in a locked position in an opening 132 formed in the release element 102. In this locked position, the release element 102 is unable to rotate. Upon detection of a force applied to the ski boot 1 above a threshold force, the lock pin 128 is moved to an unlocked position, and the release element 102 is able to rotate.
[0028] As depicted in Figure 3A, the lock pin 128 is attached to a plunger 113 of the solenoid 112. In the locked position, the solenoid 112 is deactivated and the pin 128 is forced into the opening 132 in the release element 102 by the spring 123, so that the release element 102 is unable to rotate.
[0029] The solenoid 112 is mounted in the ski boot with some play and abuts one or more sensors 130 mounted in the ski boot for detecting a force applied between the ski boot 1 and the ski 7. The force is transmitted to the sensors 130 from the release element 102 via the lock pin 128 and plunger 113 which causes the solenoid 112 to be forced against one of the sensors 130. This sensor 130 outputs a force value to the controller 105. The controller 105 then determines whether the force is excessive (i.e. it is above a speed related threshold force).
[0030] If the force is above the threshold force, the controller 105 causes the solenoid 112 to be energised and the plunger 113 is retracted into the body of the solenoid 112, thereby releasing the lock pin 128 from the opening 132. This allows the release element 102 to rotate, and the ski boot 1 to be released from the ski bindings 3.
[0031] The allowable rotation of the release element is constrained so as to prevent excessive rotation. This may be achieved as depicted in Figures 3A (locked state) and 3B (unlocked state). In the unlocked state of figure 3B, the lock pin 128 has been removed from the opening 132 which allows the release element 102 to rotate. Rotation of the release element 102 is restricted by corresponding tangs (124,125). The tangs 125 are situated either side of the opening 132 on the release element 102 and prevent excessive rotation of the release element 102. When the release element 102 rotates between the lock pin 128 and the tang 124, a side face of the tang 125 comes into contact with a side face of the tang 124, preventing rotation beyond this point.
[0032] The applied force at which the release element is allowed to rotate may be varied dependent on the speed of the skier. At low speeds, the system would adjust so that less force would be required for the release element 102 to be allowed to rotate.
[0033] In the use of ski boots 1, in accordance with the present invention, the ski boots are attached to respective skis 7 by the engagement of outer lugs 6, 106 on each boot, which form part of the respective release elements 2, 102. The lugs 6, 106 on the boots can therefore engage conventional ski bindings 3. Mechanical settings on the conventional bindings 3 will have been set with respect to the weight and size of the skier, to establish the release force at which the binding 3 should release.
[0034] When the ski boot 1 is stationary, this is detected by the speed detector 10, and this information is fed to the controller 5, 105. The controller 5, 105 then adjusts the threshold force at which the release element 2, 102 can release from the ski to a minimum setting which is lower than the release force setting of the bindings. The threshold force at which the release element 2, 102 can release the boot 1 from the binding is varied using the actuator 12, 112 controlled by the controller 5, 105.
[0035] When the skier is in motion, the speed detector 10 detects the speed at which the boot 1 is travelling. The controller 5, 105 uses this information to determine the optimum threshold force at which the skis 7 should be released from the ski boots 1. Thus, if the skier falls over when stationary or when moving slowly, causing a twisting force between the skis and the ski boot, the release element 2, 102 in each boot 1 will move to the release position, and hence the boot 1 will break free from the ski 7. This will prevent the skier being injured in a fall whilst stationary or when moving slowly. Conventional ski bindings used with conventional ski boots may not release in such a fall, potentially causing injury to the skier.
[0036] When the skier is travelling at high speed, the threshold force at which the release element 2 moves from the first engaged position to the second released position is increased, and may even be set to exceed the release force set on the bindings, since at high speed the bindings may work effectively to protect the skier from injury.
1. A ski boot comprising:
a release element for releasable attachment of the ski boot to a ski, the release element being moveable relative to the ski boot from a first engaged position in which the release element is capable of retaining the ski on the ski boot, to a second released position in which the ski is released from the ski boot, in response to a load exceeding a threshold load applied between the ski boot and a ski, and a control means adapted to vary the threshold load dependent on the speed of the ski boot.
2. The ski boot of claim 1, wherein the control means comprises a controller for adjusting
the threshold load at which the release element moves from the said first position
to the said second position.
3. The ski boot of claim 1 or 2 wherein the control means adjusts the threshold load
to release the ski boot from the ski dependent on the speed of the ski boot, as determined
by a speed detector.
4. The ski boot of any of the preceding claims, wherein the release element is adapted
to engage a binding fixed to the ski.
5. The ski boot of any of the preceding claims, wherein the release element is attached
to the ski boot at a heel and/or toe of the ski boot.
6. The ski boot of any of the preceding claims, wherein the release element is connected
to the ski boot by a sliding joint, pivot joint, or ball joint.
7. The ski boot of any of the preceding claims, further comprising a locking mechanism
for locking the release element in the first position.
8. The ski boot of claim 7, wherein the locking mechanism comprises a lock pin mounted
on the plunger of a solenoid.
9. The ski boot of claim 7 or 8, wherein the locking mechanism is switched from a locked
to an unlocked condition by the controller when the threshold load is applied to the
ski boot by a ski.
10. The ski boot of any of the preceding claims, further comprising an actuator to adjust
the preload on the release element.
11. The ski boot of claim 10, wherein the actuator is an electric actuator.
12. The ski boot of claim 10 or 11, wherein the actuator is a hydraulic actuator.
13. The ski boot of claim 2 to 12, wherein the speed detector comprises an accelerometer
or speedometer
14. The ski boot of claim 2 to 13, wherein the speed detector is located in the ski boot.
15. The ski boot of claim 2 to 14, wherein the speed detector is provided in a mobile
phone or other hand held device.