FR2780296A1 - Boot binding for snowboard - Google Patents

Abstract

The boot binding (1) for a snow board (3) has a plate (4) with a pivot (12) on the side of the contact face (6). A spring (27) returns the plate to a centralised position. A second spring (35) exerts a return force on the plate over a small angle from the central position.

Description

Device for retaining a shoe on a sliding device The invention

  relates to the field of devices for retaining a shoe on a sports machine, and more particularly relates to the retention of a shoe on a gliding board. Shoe retaining devices on a gliding board are

  used in particular in the field of skiing on snow.

  For skiing with short skis, that is to say with skis whose length is less than 1.6 meters and preferably close to 1 meter, each shoe of a user is generally retained on the ski by means of a non-triggerable fixing. For example, the binding may include two stirrups for retaining the front and rear of a shoe. this means that in all circumstances during use, the boot remains in a fixed position relative to the ski. The use of a non-triggerable attachment is justified because the length of a

  short skiing, compared to that of a traditional ski, is very reduced.

  It follows that the driving stresses are less than those exerted

with traditional skis.

  It appeared that to allow an aggressive practice, it is useful to allow a relative movement of the boot relative to the ski, while keeping the boot on the ski and ensuring its elastic return in the centered position as soon as the stress ceases. In fact, certain driving styles generate heavy loads on the torsional leg. The centered position should be understood as

  being a position in which the plate is aligned with the ski.

  It is therefore useful to provide that the boot can rotate relative to the ski

  according to a degree of freedom, so as to limit the stresses of the torsional leg.

  Document FR 1 011 091 and the first addition No. 59 385 disclose a retaining device which allows a boot to rotate relative to a ski according to a degree of freedom, without the ski separating from the boot. The device comprises a plate on which a shoe is secured, a pivot secured to the ski which allows the plate to rotate relative to the ski along an axis substantially perpendicular to the ski, and a means for elastic return of the plate in a

fixed position in relation to the ski.

  The device according to document FR 1 011 091 and the first addition No. 59 385 allows the boot to rotate relative to the ski in cases where a significant torsional force is exerted on the leg. However, this device is not completely

  satisfactory in particular for the following reasons.

  The elastic return means of the device comprises several springs, which each act according to the same compression kinematics by offering a large amplitude of movement. The amplitude is large because the effort exerted by

  each spring is weak when the plate is close to the centered position.

  It follows that the device does not ensure a sufficiently stable positioning of the boot relative to the ski during driving, which impairs driving precision. The invention particularly relates to a retaining device which allows a boot to rotate relative to the ski according to a degree of freedom, but the

  behavior is improved compared to known devices.

  A device for retaining a shoe on a sports machine according to the invention comprises a plate which has a boot face and a bearing face opposite to the boot face, means provided for retaining the boot on the face of footwear, a pivot disposed on the side of the bearing face so that its axis is substantially perpendicular to the bearing face, a first elastic return means of the plate to a centered position, the first elastic return means having a large angular movement on either side of the position

  centered, and a means provided for securing the pivot to the machine.

  The device according to the invention is characterized in that it comprises a second elastic return means of the plate towards the centered position, the second elastic return means exerting on the plate an additional return force on

  a small angular amplitude on either side of the centered position.

  The second elastic return means stably positions the plate with respect to the pivot at the centered position. It advantageously follows that the boot is held with precision relative to the ski, which allows a

precise driving.

  The second elastic return means exerts a torque only at the centered position, so that only the first elastic return means acts when the plate has rotated relative to the pivot beyond the centered position. Thus a significant torsional torque is exerted for a very short time at the knee. The torque is the restoring effort that the plate must overcome to pivot relative to the ski, thus releasing the torsional stresses exerted on the leg of the

  skier. As a result, the risk of injury is greatly reduced.

  Other characteristics and advantages of the invention will be better understood from

  using the description which follows, with reference to the accompanying drawing illustrating, by

  nonlimiting examples, how the invention can be implemented and in which: - Figure 1 is a side view in section of a retaining device according to a first embodiment of the invention, - Figure 2 is a section along II-II of Figure 1, - Figure 3 is a stiffness curve of a return spring used in the invention, - Figure 4 is a stiffness curve of another return spring used in the invention , - Figure 5 is a curve representing the torque exerted on a knee with a retaining device according to the invention, - Figure 6 is an external side view of a retaining device according to a

  second embodiment of the invention.

  The first embodiment of the invention will be described using the figures

1 to 5.

  According to FIG. 1, a retaining device 1 retains a boot 2 on a ski 3.

  In known manner, the device 1 comprises a plate 4 which has a boot face 5 and a bearing face 6 opposite to the boot face 5. The device 1 also comprises means provided for retaining the boot 2 on the face 5 , the means being represented in the form of a stirrup 7 towards the front of the device 1 and of a stirrup 8 associated with a handle 9 towards the rear of the device 1. The position of the stirrup 7 is adjustable longitudinally on the plate 4 by means of orifices 10, and the position of the stirrup 8 is adjustable longitudinally on the plate 4 by means of orifices 11. The handle 9 allows manual attachment or detachment

  of shoe 2 relative to plate 4.

  The device 1 also includes a pivot 12 whose axis 13 is oriented

  substantially perpendicular to the bearing face 6.

  The pivot 12 is located on the side of the bearing face 6 of the device 1. The device 1 comprises a means for securing the pivot 12 to the ski 3, represented in the form of a shoulder 14 of the pivot 12 and of the screw 15 serving to screw the shoulder 14 onto the ski 3.

  The connection of the pivot 12 to the plate 4 is done as explained below.

  The pivot 12 has successively, in a direction away from the shoulder 14, a cylindrical portion 16, an intermediate portion 17, and a cylindrical portion 18. The portions 16 and 18 have the same diameter and serve as

  guide in rotation of the plate 4, cooperating with a bore 19 of the plate 4.

  A cap 20, held on the pivot 12 by a means such as a pin screw 21,

  maintains the plate 4 on the pivot 12 to prevent translation along the axis 13.

  Antifriction rings 22, 23 facilitate rotation of the plate 4 with respect to the pivot 12, by reducing friction on the one hand between the shoulder 14 and the plate 4,

  and on the other hand between the cap 20 and the plate 4.

  Thus, the plate 4 is guided in rotation relative to the pivot 12, which amounts to saying that the boot 2 is guided in rotation relative to the ski 3 in a plane

substantially parallel to the ski 3.

  The pivot 12 is located in a central region of the plate 4, substantially halfway

  path between a front end 24 and a rear end 25 of the plate 4. The axis of the leg of a user, symbolized by a line 26, is located near the axis 13

pivot 12.

  The device 1 also comprises a first elastic return means, the

  structure and operation are explained using figure 2.

  The device 1 is shown in a centered position which it occupies during use in a case where the torsional forces along the axis 13 are included in

below a reference threshold.

  The first elastic return means comprises a return spring 27 which biases a return finger 28 in a direction substantially perpendicular to the axis 13 of the pivot 12. An adjustment means, represented in the form of a screw 29, makes it possible to adjust the force that the spring 27 exerts on the finger 28 by resting on the screw 29. The spring 27 is a helical spring guided by a pin 30. The finger 28, the pin 30, the spring 27 and the screw 29 are arranged in a housing 31 of the

plate 4.

  1 5 The pivot 12 has, at the intermediate portion 17, a groove 32 with a flat bottom 33. The bottom 33 is substantially parallel to the axis 13, and the groove 32 is positioned on the pivot 12 so that the finger recall 28 tends to lean

on the merits 33.

  The finger 28 has a flat end 34, and cooperates with the pivot 12 in the following manner. The spring 27 biases the finger 28 towards the pivot 12 so that the end 34, which is

  substantially perpendicular to the axis of the spring 27, comes to bear on the bottom 33.

  When the tip 34 is fully in contact with the bottom 33, the device 1 is in the centered position which allows the ski 3 to be driven. The plate 4 along its length is then oriented in the direction of the length of the ski 3. It s follows that shoe 2, not

  shown in FIG. 2, is also oriented along the length of the ski 3.

  When a torque causes a rotation of the plate 4 with respect to the ski 3 along the axis 13 of the pivot 12, the flat bottom 33 and the flat end 34 form an angle which is the same as the angle of rotation of the plate 4 with respect to the ski 3. This case is not shown. However, looking at FIG. 2, it appears that during a rotation of the plate 4 relative to the ski 3, the spring 27 is compressed and

  that, by reaction, it tends to return the plate 4 to the centered position.

  We can summarize the function of the first elastic return means by saying that the latter recalls the plate 4 in the centered position when the latter rotates by

  relative to pivot 12 at a large angle of travel.

  The foregoing has not been described in more detail as it is known

of a person skilled in the art.

  Now, according to the invention, the device 1 is also provided with a second elastic return means which opposes a rotation of the plate 4 relative to the

  pivot 12 at the centered position.

  Looking at Figure 2, we see that the second elastic return means comprises a stop spring 35 which biases a stop finger 36 in a direction substantially perpendicular to the axis 13 of the pivot 12. An adjustment means, shown in the form of a screw 37, adjusts the force that the spring 35 exerts on the finger 36 by resting on the screw 37. The spring 35 is a helical spring. The

  finger 36, the spring 35 and the screw 37 are arranged in a housing 38 of the plate 4.

  The pivot 12 has, at the intermediate portion 17, a notch 39 with a concave bottom. The notch 39 is positioned on the pivot 12 so that the stop finger 36 enters the notch 39 when the plate 4 is in the centered position which

allows the device 1 to be driven.

  The stop finger 36 has a convex end 40 whose shape is

  substantially complementary to that of the notch 39 of the pivot 12.

  The operation of the second elastic return means is as follows.

  In the centered position, the finger 36 is in abutment in the notch 39 because the spring 35 biases the finger 36 towards the pivot 12. When the plate 4 is biased in relation to the pivot 12, the finger 36 is opposed when the plate 4 rotates relative to the pivot 12 under the thrust of the spring 35 as long as a limit threshold L is not reached. Beyond a limit torque, the finger 36 is pushed back towards the screw 37

  by action of the notch 39 on the end 40.

  This phenomenon occurs for a low angular amplitude of the plate 4 relative to the pivot 12. During the rotation of the plate 4 according to the low angular amplitude around the centered position, the finger 36 exerts on the pivot 12 a force

important to overcome.

  These are the shapes of the notch 39 and the end 40 which allow the pivot 12 to push the finger 36 when the limit torque is reached. After rotation of the plate 4 with respect to the pivot 12, the end 40 of the finger 36 presses on a peripheral surface 41 of the portion 17 of the pivot 12 without causing the spring 35 to vary in tension. As a result, the second means of recall no longer opposes the rotation of

  the plate 4 relative to the pivot 12.

  Of course, it should be understood that the first and second return means each act in proportion to the rotation of the plate 4 to obtain a

  effect explained using Figures 3 to 5.

  The first elastic return means urges the plate 4 towards the centered position, so that the finger 36 enters the notch 39 when the plate 4 is in

the centered position.

  FIG. 3 represents the stiffness of the return spring 27. The abscissa axis corresponds to a compression deformation of the spring 27, and the ordinate axis

  corresponds to the force exerted by the spring in proportion to its compression.

  FIG. 4 is similar to FIG. 3, but it corresponds to the stop spring 35.

  The value scales are identical in FIGS. 3 and 4. By comparison, it appears that the stiffness of the stop spring 35 is greater than the stiffness of the spring.

reminder 27.

  FIG. 5 shows the variation of the torque exerted by the device 1 on a knee, as a function of time or of the angle of rotation of the plate 4 relative to the pivot 12. The abscissa axis can represent both time and the angle of rotation, because the angle of rotation varies substantially in proportion to the duration of application of a torsional stress. The ordinate axis represents the

  torque exerted in the device 1 by the return means taken in combination.

  The initial torque increases very quickly up to the safety limit threshold L.

  Then, the torque drops to a reduced but not zero value.

  In the absence of stress, the torque is zero. If a stress appears until reaching the limit threshold L, it is essentially the second return means which opposes a rotation of the plate 4 relative to the pivot 12. When the second return means ceases to act as it has been explained before, the first return means continues to urge the plate 4 towards the centered position so that the

  device 1 exerts a reduced torque on the user's leg.

  The device 1 exerts on a leg a high torque for an amplitude

  weak angular then, if the stress persists, it exerts a reduced torque.

  The second embodiment of the invention is presented using FIG. 6. A retaining device 70 is provided for retaining a shoe that is not

shown on the ski 3.

  The constituent elements of the device 70 can be those of the first embodiment, with the exception of the means provided for retaining the boot on a shoe face 71. These means comprise a shell 72 which retains the boot using straps 73 , 74, 75. The shell 72 allows the use of a flexible shoe with the

device 70.

  Whatever the embodiment of the invention, the constituent parts of the device can be made with materials and implementation techniques known to those skilled in the art. Metals, metal alloys, materials

  plastics or composites are among the known materials.

  Of course, the invention is not limited to the embodiments described, and includes all the technical equivalents which may fall within the scope of the

claims which will follow.

  In particular, the return means could have different structures, each comprising several springs, or different springs. The

  connection of the pivot to the plate could also have a different structure.

Claims (8)

  1- Device (1, 70) for retaining a shoe (2) on a sports machine (3), the device (1, 70) comprising a plate (4) which has a boot face (5, 71) and a bearing face (6) opposite the boot face (5, 71), the device (1, 70) comprising means provided for retaining the boot (2) on the boot face (5, 71), a pivot (12) disposed on the side of the bearing face (6) so that its axis (13) is substantially perpendicular to the bearing face (6), a first means of elastic return of the plate (4) towards a centered position, the first elastic return means having a large angular clearance on either side of the centered position, and a means provided for securing the pivot (12) to the machine (3), characterized by the fact that it comprises a second elastic return means of the plate (4) towards the centered position, the second elastic return means exerting on the plate (4) an additional return force on a small amount angular fullness on either side of the centered position.   2- retaining device (1, 70) according to claim 1, characterized in that the first elastic return means comprises a return spring (27), in that the second elastic return means comprises a return spring (35), the stiffness of the return spring (35) of the second means being greater than the stiffness of the   return spring (27) of the first means.   3- retainer (1, 70) according to claim 2, characterized in that the return spring (27) of the first means biases a return finger (28) in a direction substantially perpendicular to the axis (13) of the pivot (12), and by the fact that the return spring (35) of the second means biases a return finger (36) in a   direction substantially perpendicular to the axis (13) of the pivot (12).   4- retainer (1, 70) according to claim 3, characterized in that the pivot (12) has a groove (32) with a flat bottom (33), the bottom (33) being substantially parallel to the axis (13), the groove (32) being positioned on the pivot (12) so that the return finger (28) of the first means tends to bear on the bottom (33), and by the fact that the pivot (12 ) has a notch (39) with a concave bottom, the notch (39) being positioned on the pivot (12) so that the return finger (36)   the second means tends to bear on the bottom of the notch (39).   - Retaining device (1, 70) according to any one of claims 2 to 4,   characterized by the fact that the return springs (27, 35) are helical springs   respectively housed in housings (31, 38) of the plate (4).   6- retainer (1, 70) according to any one of claims 2 to 5,   characterized by the fact that adjustment means make it possible to adjust the forces,   exerted by the return springs (27, 35).   7- retainer (1, 70) according to any one of claims 1 to 6,   characterized in that the pivot (12) is located in a central region of the plate (4).   8- retainer (1) according to any one of claims 1 to 7,   characterized in that the means provided for retaining the shoe comprise stirrups (7, 8).   9- retaining device (70) according to any one of claims 1 to 7,   characterized in that the means provided for retaining the shoe comprise a shell (72).