EP0385946B1 - Safety ski binding - Google Patents

Abstract

Binding intended for the fastening of the front of the boot or of the heel, comprising a body (13), pivoting (14) or fixed, equipped with a jaw (15) articulated on the body about a horizontal spindle (16). The body and the jaw are held in a closed position by at least one spring (18) acting by means of a piston (17) on a transmission device comprising two moving parts (21, 24) articulated on each other. One of these moving parts (21) permanently bears on the jaw and the other moving part (24) permanently bears against lateral retention means consisting, for example, of two fixed stops (10) on which bear levers (33a) acting on a transmission member (26). In particular, a lateral displacement of the body or of the boot, respectively, results in a reduction in the vertical pressure of the jaw on the boot. <IMAGE>

Description

The present invention relates to a safety ski binding intended to hold the heel or the end of the foot, comprising a body, a jaw articulated on this body around a horizontal axis, means for lateral retention of the boot, means elastic, at least partly common, for returning the lateral retaining means and the jaw to the closed position of the fastening, these return means comprising at least one spring acting by means of at least one piston on a mechanism transmission, mobile in rotation or in translation, interposed between, on the one hand, the piston and, on the other hand, the jaw and the lateral retaining means.

A binding of this type is known from European document EP-A-0 202 440. In this binding, the transmission mechanism consists of a lever articulated on the body of the binding and pressing by a flat face against the face flat front of the piston. The purpose of this lever is to reduce the resistance of the attachment to torsion when the spring is already compressed by the vertical movement of the jaw, this in order to facilitate the release of the attachment in the event of a forward fall accompanied by a torsion. However, this lever does not make it possible to control the forces in a precise manner and a torsional stress does not have the effect of reducing the resistance in the vertical direction as would be desirable.

Document DE-A-28 12 149 also discloses a fastening with a pivoting body in which the pressure on the heel disappears completely when the body is driven in rotation. This attachment includes a stop fixed formed by a vertical flat of the pivot against which is held in abutment a lever in the form of a rocker articulated at the end of the piston. The articulated jaw is supported on the upper part of this lever by a transverse bar moving in a lumen of the body. According to another embodiment described in this document, a lever is articulated by its lower end between the piston and the spring, the flat end of the piston coming to bear against the flat part of the stop. In this case also the articulated jaw rests on the upper end of the lever by a transverse bar. In both cases, as soon as the body of the binding is rotated following a twist on the leg, a clearance appears between the transverse bar of the jaw and the lever, so that the foot begins to float in the binding, such a float that can cause a feeling of insecurity, especially in the case of the heel, and reactions likely to cause a fall, while the simple twist would not have resulted in the fall.

The object of the present invention is to provide a transmission mechanism such that it makes it possible to continuously control the interdependence of the forces and reactions exerted vertically and horizontally by the binding to the shoe and, in particular, to ensure a reduction progressive vertical pressure of the jaw on the shoe during a torsional stress and vice versa, and this without appearing a harmful play, at any time, in the binding.

The binding according to the invention is defined in claim 1.

The transmission mechanism according to the invention makes it possible to control the forces necessary to trigger the binding at all times, in all directions and in all the intermediate positions of the binding. It is thus possible to produce a binding offering optimal triggering characteristics.

Preferably, the mobiles are permanently in linear contact respectively with the piston, the jaw and the stop, so that the wear of the parts in contact is negligible and does not affect the proper functioning of the fixing.

The accompanying drawing shows, by way of example, seven embodiments of the invention.

Figure 1 is an axial vertical sectional view along I-I of Figure 2 of a front stop according to a first embodiment.

Figure 2 is a sectional view along IIa-IIa and IIb-IIb of Figure 1.

Figure 3 partially shows the same fixation during triggering in rear fall.

Figure 4 partially shows the same attachment during torsional triggering.

FIG. 5 partially shows the same fastening biased diagonally, that is to say when falling back and in torsion.

Figures 6 to 9 show an alternative embodiment of the first embodiment and correspond respectively to Figures 1, 2, 3 and 5.

Figure 10 is a vertical axial sectional view of a front stop according to a third embodiment.

Figure 11 is a sectional view along XI-XI of Figure 10.

Figure 12 partially shows the same attachment during triggering in rear fall.

Figure 13 partially shows the same attachment during torsional triggering.

Figure 14 is a vertical axial sectional view of a front stop according to a fourth embodiment.

Figure 15 is a vertical axial sectional view of a front stop according to a fifth embodiment.

Figure 16 is a vertical axial sectional view of a front stop according to a sixth embodiment.

Figure 17 is a sectional view along XVII-XVII of Figure 16.

Figure 18 partially shows the binding according to Figures 16 and 17 during tripping before falling.

Figure 19 partially shows the same attachment during torsional triggering.

FIG. 20 partially represents a seventh embodiment, derived from the third embodiment, being triggered in torsion.

Figure 21 shows schematically a front stop with fixed body.

FIG. 21a represents the forces acting on the part 24 of FIG. 21.

FIG. 22 is a plan view of the lateral retaining means of the stop represented in FIG. 21.

Figure 23 schematically shows another front stop with fixed body.

The front stop shown in Figures 1 and 2 comprises a body 13 pivotally mounted on a ski 2 by means of a pivot 14. On the body 13 is articulated a jaw 15 about an axis 16. The position of the jaw 15 shown in Figure 1 is the position in which it presses the front of a shoe 1 against a plate 3 of material with a low coefficient of friction. The body 13 has a horizontal bore 46 in which slides a piston 17 pushed forward by a spring 18 working in compression and whose compression can be adjusted by means of a threaded plug 19 screwed into the bore 46. The part front of the body 13 has a vertical slot 20 limited by two cheeks 13a and 13b of the body 13 (Figure 2) and in which is mounted a first lever 21 extending approximately vertically and articulated at its lower end about an axis 22 on the body 13. This first lever 21 is provided with a spout 21a ending in a rounded rectilinear edge resting linearly on a ramp 15a of the jaw 15 under the thrust of the spring 18. On the lever 21, near its end upper, is articulated around an axis 23 a second lever 24 extending downward and applied against the first lever 21 by the piston 17. The lever 24 bears against the piston 17 by a convex cylindrical surface risk of generators parallel to the axes 22 and 23. At its lower end, the second lever 24 has a vertical central slot 25 in which is engaged a horizontal axial transmission rod 26 having at one of its ends a widening 28 extending between the split end of the second lever 24 and the first lever 21, and at its other end a head 39 on the rear of which the ends of two levers 33 and 34 are pivoted respectively, at an intermediate point, around two vertical axes 35 and 36 in the body 13. These two levers 33 and 34 are identical and mounted identically symmetrically to the vertical plane of symmetry 12 of the binding. However, they appear different in FIG. 2 due to the different cutting levels IIa and IIb shown respectively below and above the axis 12 in FIG. 2. The levers 33 and 34 bear against the head 39 by a split end such as 33a. The other end of the lever 33 is pressed against a fixed stop 10, while the other end of the lever 34 is pressed against a second fixed stop 11, the stops 10 and 11 being arranged symmetrically to the axis 12.

In the position shown in Figures 1 and 2, that is to say the carriageway position without dangerous stress, the spring 18 maintains the jaw 15 in the folded position and it further pulls the rod 26 forward of the second lever 24. By its range 39, the rod 26 supports the levers 33 and 34 on their stops 10 and 11, which has the effect of keeping the binding aligned on the axis of the ski, due to the symmetry of the construction. If the binding is used as a heel piece, it will also comprise a lever known per se, not shown for manually opening and closing the jaw for shoeing and putting on the shoes respectively, and the jaw will be provided with a spur for closing it with the heel. The axis 23 crosses the cheeks 13a and 13b through two slots 28 in an arc centered on the axis 22.

The operation of the binding, both as a front stop and as a heel piece will be described in relation to FIGS. 3 to 5.

Let us first examine the case of a front stop. If the stop is biased in torsion, the shoe tends to drive the jaw 15, and consequently the body 13 in rotation around the pivot 14. Depending on the direction of rotation, one or the other of the levers 33 and 34 pivots around its axis by resting on its stop 10, respectively 11, which has the effect of causing the second lever 24 which pivots on the first lever 21, the latter remaining stationary. The piston 17 is pushed back by compressing the spring 18, as shown in FIG. 4. Beyond a certain angle of rotation of the body 13, the shoe laterally escapes from the binding. If the torsional stress is insufficient to cause tripping, the reduction in the pressure of the lever 21 on the jaw 15 allows only a slight pivoting of this jaw. The spout 21a moves very little on the ramp 15a of the jaw. By reducing the vertical pressure we reduce friction. After triggering the binding is returned to its initial position by the spring and the action of the levers and ramps.

The case of a combined fall in torsion and rear fall is shown in Figure 5. This position results from the combination of displacements shown in Figures 3 and 4.

The triggering of the stop in rear fall is shown in Figure 3. Under the effect of the fall back, the jaw 15 is lifted by the end of the foot by pushing the spout 21a of the lever 21 which compresses the spring 18 by pushing the piston 17. The shoe is released when the spout 21a reaches the end 22a of the ramp 15a of the jaw 15. This end 22a is not exceeded, so that the jaw 15 is returned to its initial position under the thrust of the spring and by the cam effect of the ramp 15a. Note that in this case the second lever 24 does not intervene and the rod 26 remains stationary; the levers 21 and 24 behave like a single lever.

In the case where the binding is used as a heel piece, the behavior only differs in one point: when falling before the end 22a of the ramp 15a is exceeded and the jaw remains open after release, the beak 21a of the lever 21 s pressing against the surface 22b of the jaw.

These considerations are applicable to all of the embodiments described.

If we examine the fulcrum, more precisely the fulcrum, of the piston 17 against the second lever 24, we see that in Figure 1 this fulcrum is approximately halfway between the axis 23, point of action of the reaction force of the jaw and the lower end of the lever 24, point of action of the reaction force of the stops 10 and 11. In FIG. 3, it can be seen that this point d action has moved in the direction of axis 23, at point A, while in figure 4 this action point has moved downwards, at point B. There is therefore a variation in the lever arm of the reaction forces relative to the fulcrum of the piston. This variation is particularly favorable, as will be explained with the aid of FIGS. 1a, 3a and 4a, which schematically represent three states of equilibrium for three characteristic states of the binding. P1 is the force exerted by the jaw 15 on the axis 23 of the lever 24. P2 is the force exerted on the end 25 of the lever 24 by the reaction of the stops 10 and 11. P3 is the force exerted by the piston 17 on lever 24. The system being in equilibrium P3 = P1 + P2. The lever arms of forces P1 and P2 are designated by a and b.

En divisant par P2 . a on obtient $$\frac{\text{P1}}{\text{P2}}\text{=}\frac{\text{b}}{\text{a}}$$

The system being in equilibrium, we have, relatively to the point of application of the force P3 $$\text{P1. a = P2. b}$$

Dividing by P2. a we get $$\frac{\text{P1}}{\text{P2}}\text{=}\frac{\text{b}}{\text{at}}$$

The ratio of forces P1 and P2 is therefore equal to the inverse ratio of their lever arms. The length of these lever arms therefore plays a very important role in determining the triggering forces of the binding. It also appears from FIGS. 3a and 4a that these lever arms a and b vary thanks to the convex shape of the lever 24. By means of this convex shape and the progressive characteristic of the spring, it is possible to obtain a behavior determined in diagonal release, that is to say in the case of a fall forward accompanied by a twist.

Diagonal behavior is favorable if the torsional energy required for tripping is less than the torsional energy required for tripping in pure torsion. However, if we compare Figures 4 and 5, we see that this is indeed the case, since the lever arm b is significantly shorter in the position according to Figure 4 than in the position according to Figure 5, hence it follows that P2 is significantly higher in the case of FIG. 4.

Conversely, the energy required for triggering a fall from the front or back, respectively, should decrease if the leg is simultaneously subjected to a torsion. However this is indeed the case since the lever arm has force P1 is larger in the position according to Figures 4 and 4a than in the position according to Figures 3 and 3a, which means that, conversely, P1 is smaller in diagonal triggering than in triggering in pure forward fall. In all cases the diagonal tripping does not result from the addition of the forces necessary for the tripping in forward fall and in torsion, respectively, but the forces required are on the contrary reduced, which is in accordance with the teaching concerning the resistance of the leg in the event of superposition of bending and torsional forces.

The lever 24 could be articulated on the rod 26. This variant is shown in FIGS. 6 to 9. The lever 24 ′ corresponding to the lever 24 is articulated on the rod 26 ′ by means of an axis 4. So as to that this articulation 4 does not hinder the movement of the levers 21 and 24 ′, the lever 24 ′ has a slot 5 for the passage of the articulation axis 23 of the two levers. FIGS. 8 and 9 illustrate the displacement of the axis 23 in the lumen 5 for two characteristic positions, namely during triggering in rear fall, respectively in combined fall in torsion and in rear fall.

It can also be seen that, with a relatively very simple construction, it has been possible to keep permanent linear conctates between the spout 21a of the lever 21 and the ramp 15a of the jaw 15, between the piston 17 and the lever 24, and between the stops 10 and 11 and the levers 33 and 34. However, such a linear contact has, on the point contact devices used until now, the advantage of much lower wear and much less sensitivity to soiling. Occasional contacts appearing so far in fasteners, whether by a ball, a spherical cap or an edge on a cylindrical surface, have the effect of causing the formation of a recess due to wear, recess which completely changes the characteristics of the fastener and can make security illusory. The linear contacts also allow the use of less hard metals, or even plastics.

A third embodiment of the invention will now be described in relation to FIGS. 10 to 13. In order to simplify the description and avoid unnecessary repetitions, the parts of the binding identical to the first embodiment or not having undergone only minor modifications are designated by the same references. In this embodiment, the levers 33 and 34 bear directly on the lower end of the second lever 24 by their ends 33a and 34a. In the bore 46 is mounted a piston 45 on which a first spring 47 acts, the precompression of which can be adjusted by means of a threaded plug 48. The piston 45 has, at its lower part, a rib 49 engaged in a guide groove 50 to maintain the piston 45 in a determined angular position in its bore. The front face of the piston 45 bearing against the curved face of the lever 24 is not continuous, but extends only over the lower half of this front surface. The upper part is occupied by a second piston 52 on which acts a second helical spring 53 coaxial with the spring 47, but of smaller diameter so as to rest only on the piston 52. The precompression of the spring 53 can be adjusted individually by means of a threaded plug 54 screwed into the threaded plug 48. The piston 52 is also integral with a guide rod 55 sliding in a bore 56 provided in the threaded plug 54.

When falling backwards (for a front stop) without significant torsion, the jaw 15 pushes the first lever 21 and with it the second lever 24 which simultaneously pushes the pistons 45 and 52 by compressing the two springs 47 and 53 (FIG. 12). The effort required is significant and also grows rapidly with the lifting of the jaw 15.

On the other hand, in pure torsion (FIG. 13) one of the levers 33 or 34, for example the lever 33 drives the lower end of the second lever 24 by its arm 33a. In its movement, the lever 24 mainly pushes the piston 45 and slightly only the piston 52, so that it is the external spring 47 which is mainly compressed. It is therefore possible to adjust the elastic resistance to triggering in reverse fall and in torsion differently. In addition, as in the first embodiment, and for the same reasons, the vertical pressure of the jaw on the shoe decreases when the binding is driven in torsion.

A fourth embodiment is shown in Figure 14. As in the previous cases it can be both a stop before a heel. Parts identical or similar to those of the first embodiment have been designated again by the same references. We find in this embodiment practically the same body 13 and the same levers 21 and 24, as well as the piston 17 and a single spring 18. This fourth embodiment differs from the first embodiment by the means of return of the body 13 in torsion: the body 13 carries a lever 71 articulated on a transverse horizontal axis 72 and bearing a roller 73 rotatably mounted on an axis perpendicular to the axis 72. The end 71a of the lever 71 bears against the lower end of the lever 24, while the roller 73 rests against a fixed stop 74 in the form of cam having the shape of a symmetrical undulation whose hollow is located on the axis of the ski. Under the thrust of the spring 18, the roller 73 tends to remain, respectively to return to the bottom of this undulation.

During a torsional stress, the roller 73 is pushed back by the cam 74, which makes the lever 71 pivot anticlockwise, which causes the lever 24 to tilt as in FIG. therefore finds the same conditions as in the first embodiment with the same effects.

A fifth embodiment is shown in Figure 15. The binding shown, which can again be a front stop or a heel piece, comprises a body 13˝ pivotally mounted on a vertical pivot 61 on which it is retained by a pin 22 ˝ engaged in a groove 63 of the pivot 61. The pin 22˝ simultaneously constitutes the pivot axis of a jaw 64 on the body 60. This jaw 64 is provided, in a known manner, with a part 65 adjustable in height by means of a screw 66 and pressing on the shoe 1.

The body 13˝ has a horizontal bore 67 in which is mounted a piston 17˝ on which acts a spring 18˝ resting on the other hand on a threaded plug 19˝ for adjusting the precompression of the spring 18˝. The piston 17˝ is pressed against a lever 24˝ whose upper part is articulated on the jaw 64 by means of an axis 72 parallel to the axis 22˝ and whose end lower 23˝ is articulated, without auxiliary means, on a sliding part 85 in the form of a square, the vertical part of which rests against a vertical flat 70a formed on an extension of the pivot 61. This flat 70 is close to the axis geometric of the pivot 61. The horizontal part of the sliding part 85 rests on a flat face 76 of the body 13˝ and on a horizontal flat face of the pivot 61. The part of the jaw 64 pivoting on the body 13˝ is made up of 'a folded sheet metal part having two wings extending on each side of the body 13˝. The axis 72 therefore crosses the body 13˝ which has at this location two slots 77 in an arc allowing the jaw to tilt. The lever 24˝ also has a light 60 in the direction of the axis 22˝.

When the body 13˝ is rotated around its pivot 61, one of the vertical edges of the flat 70 pushes the part 85 by rotating the lever 24˝ clockwise around its end 23˝ . As in the first embodiment, the point of contact of the piston 17˝ against the lever 24˝ moves away from the axis 72, which has the effect of reducing the vertical pressure of the jaw 64 on the shoe, this pressure remaining nevertheless sufficient to keep the shoe applied against the ski, unless the torsion is accompanied by a fall, forward for a heel and respectively back for a front stop. In this case the axis 72 is rotated counterclockwise around the axis 22˝ and the lever 24˝ rotates in the same direction by pushing the piston 17˝, the axis 72 bringing the piston 17˝ again, in a position similar to or close to the position shown in the drawings.

A sixth embodiment of the binding according to the invention will now be described in relation to FIGS. 16, 17, 18 and 19. By way of simplification and to avoid repetition, the parts of this binding similar to those of the first or of the third embodiment are designated by the same references, even if these parts have undergone some modifications of form. The parts corresponding to levers 21 and 24 have been designated by 21˝˝ and 24˝˝. We thus find a body 13 pivotally mounted on the ski 2 by means of a pivot 14 and having a bore 46 in which are mounted two coaxial springs 47 and 53 whose precompression can be adjusted separately by means of two threaded plugs 48 and 54 as in the third embodiment. In this case, the hinge pin 16 of the jaw 15 passes through the bore 46. The first lever 21 is replaced here by a slide 21˝˝ sliding in the bore 46 and resting on the rounded rectilinear edge 57 of an anterior spout on the ramp 15a of the jaw 15 under the thrust of the internal spring 53. At the rear of the slide 21˝˝, in the upper part of the latter, is articulated around an axis 23 , a lever 24˝˝ corresponding to the second lever 24 of the previous embodiments. This lever has at the front two transverse wings 60 slightly curved against which abuts a piston 61 sliding in a bore 62 of the slide 21˝˝ and on which acts the external spring 47. This spring 47 therefore acts on the lever 24 ˝˝ whose curved wings 60 are the equivalent of the curved surface of the lever 24 of the previous executions. The lower end of the lever 24˝˝ carries a vertical axis 65 on which a roller 66 is rotatably supported, under the effect of the spring 47, against the bottom of a ramp fixed 67 similar to the ramp 74 in Figure 14. It should also be noted that the axis 16 of the jaw 15 crosses the slide 21˝˝ through a light 68 so as to allow the movement of the slide 21˝˝ and qu 'A clearance 69 is provided between the front end of the piston 61 and the bottom of the bore 62 of the slide 21˝˝ against which the internal spring 53 is supported.

In the event of a front fall without torsion, the slide 21˝˝ is pushed back by the jaw 15 by compressing the two springs 47 and 53, as shown in FIG. 18. The lever 24˝˝ rocks slightly on the ramp 67 of such so that the fulcrum of the piston 61 on the domed wings 60 moves upwards, as in the previous embodiments.

During a strong twist on the binding, the body 13 pivots and the roller 66 moves on the ramp 67, on one side or the other of the position shown in FIG. 17, which has the effect of drive the lever 24˝˝ and the piston 61, which compresses the spring 47 as shown in FIG. 19. The fulcrum of the piston 61 on the domed wings 60 moves downwards, as in the previous embodiments. The slide 21˝˝ remains stationary and the spring 47 is not compressed. After lateral escape of the shoe, the ramp 67 returns the body 13 to its initial position. If the binding is stressed both in torsion and by a front or rear drop depending on whether it is a heel piece or a front stop, the displacements shown add up, but not the energies.

In the case of the first and second embodiments, it is also possible to provide two springs acting respectively only on one of the levers 21 and 24. Starting from FIG. 10, such an execution can be obtained by modifying the shape of the levers 21 and 24 and the shape of the pistons 45 and 52. Such a modification is shown in the Figure 20. The relatively narrow lever 24˝ ′ is mounted in a groove 79 of the lever 21˝ ′. The end of the outer piston 45 ′ has two wings 80 which come to bear respectively on the lever 21 "'on each side of the groove 79. The width of the inner piston 52 ′ is equal to the width of the lever 24˝ ′.

The principle according to the invention is also applicable to a fixing with a fixed body. Figures 21 and 22 very schematically represent a first embodiment.

The binding comprises a fixed body 13 on which a jaw 15 is articulated about a horizontal axis 16. The shoe 1 is retained laterally by two levers 33 ′ and 34 ′ pivoting on fixed vertical axes 35 ′ and 36 ′. One of the ends of the levers 33 ′ and 34 ′ rests on the head 81 of a pull-up bar 86 (first mobile), the other end of which is articulated by an axis 23 at the end of a lever 24 (second mobile) whose other end has a spout 24a resting on a ramp of the jaw 15. On the convex face of the lever 24 is supported a piston 17 pulled by a spring 18 which is supported on a part 82 secured to the body 13. We find the same diagram of forces as in FIG. 1a (represented in FIG. 21a) and the same Considerations are applicable with regard to the variation of the lever arms and of the forces P1 and P2 and of the vertical pressure exerted by the jaw 15 on the shoe. Used as a front stop, this construction also has the advantage of automatically adapting the height of the jaw to the shoe.

The variant shown schematically in Figure 23 differs from the previous embodiment only in the mode of application of the force of the lever 24 to the jaw. In this case, the lever 24 is articulated at the end of an arm 83 of the jaw 15 around an axis 84.

In all embodiments, the same effect could be obtained by giving the piston a cylindrical convex shape and a plane bearing face on the levers 24, 24 ′, 24˝.

Claims (18)

1. A ski safety binding able to release horizontally and vertically intended to hold in place the heel or the end of the foot, comprising a body (13; 13′), a grip (15; 64) articulated on this body about a horizontal pin, lateral-retention means (33, 34, 10, 11; 66, 67; 73, 74; 70; 33′, 34′, 35′ 36′), for the boot, elastic means, which work together at least partly, for returning the lateral-retention means and the grip into the closed position of the binding, these return means comprising at least one spring (18; 47, 53; 18˝) acting via at least one piston (17; 45, 52; 17˝; 61) on a transmission mechanism, capable of rotational or translational movement and set between, on the one hand, the piston and, on the other hand, the grip and the lateral-retention means, characterized in that the transmission mechanism comprises essentially a first part constituted of a forces repartition rocking lever (24; 24′; 24˝; 24˝′; 24˝′) capable of rocking in a plane perpendicular to the articulation axis of the grip, said rocking lever bearing permanently against the piston and bearing directly or indirectly on the one hand against the grip and on the other hand against the lateral-retention means in such a way that the position of said rocking lever is determined at each instant by two forces (P1, P2) acting on both opposed ends of the rocking lever, said forces corresponding to different releasing directions, and by a third force (P3) acting between the two first forces via the piston (17) and that the rocking lever and/or the piston have a convex bearing surface in such a way that when the rocking lever is rocking the bearing zone is moving downwards or upwards relatively to the piston modifying thereby gradually the lever arms (a, b) of the forces (P1, P2) acting on the rocker ends.

2. The binding as claimed in claim 1, characterized in that the body (13) is mounted pivotably on a vertical pivot (14, 61) and the lateral-retention means comprise at least one fixed stop (10, 11, 74; 75)

3. The binding as claimed in claim 2, characterized in that the transmission mechanism comprises a second part (21; 21′; 21˝′; 21˝˝) movable relatively to the first part between the first part and the grip and bearing permanently against the first part and the grip.

4. The binding as claimed in claim 2 or 3, characterized in that all the moving parts of the transmission mechanism are in permanent linear contact with the piston, the grip and the stop respectively.

5. The binding as claimed in claim 3, characterized in that the second part consists of a lever (21) articulated about an axis parallel to the axis of articulation of the grip and provided with a nose (21a) bearing against an incline (15a) of the grip and that the rocking lever (24) is articulated in the upper part of said lever about an axis (23) parallel to the axis of articulation of the grip, extending downwards and the end of which bears directly or indirectly against the stop or stops (10, 11; 74) respectively for returning the body under torsion.

6. The binding as claimed in claim 5, characterized in that the articulation of the first lever (21) is secant to the axis of pivoting of the said body and the lower end of the second lever (24) bears against at least one lever (33, 34; 71), one arm of which bears against the fixed stop.

7. The binding as claimed in claim 6, characterized in that the rocking lever (24) bears, via a transmission rod (26), against two levers (33, 34) pivoted about two vertical axes symmetrically on each side of the longitudinal axis of the binding, and one arm of which bears respectively against two fixed stops (10, 11) arranged symmetrically on either side of the said longitudinal axis.

8. The binding as claimed in claim 6, characterized in that the end of the rocking lever (24) bears against a lever (71) which pivots about a horizontal axis perpendicular to the plane of rocking of the rocking lever, this lever (71) being provided with a roller (73) bearing against a stop in form of a cam (74).

9. The binding as claimed in claim 5, characterized in that said binding comprises two coaxial springs (47, 53), one of these springs interacting with a first piston (45) bearing against the curved part of the rocking lever (24) in the closed position of the binding, the second spring (53) acting on a second piston (52) capable of being pushed back by the first piston (45), the rocking lever (24) also bearing against the second piston (52) when the grip is raised.

10. The binding as claimed in claim 3, characterized in that the second part consists of a slide (21˝˝) bearing against the grip (15) and on which a first spring (53) acts and the rocking lever (24) is articulated, at one of its ends, on the said slide, a second spring (47) acting on the rocker via a piston (61).

11. The binding as claimed in claim 5, characterized in that the said binding comprises two coaxial springs (53, 47), one (47) of these springs interacting with a first piston (45′) exclusively against the lever (21˝′), the second spring (53) interacting with a second piston (52′) exclusively against the rocking lever (24˝′).

12. The binding as claimed in claim 11, characterized in that the lever (21˝′) and the first piston (45′) have a U profile shape and said rocking lever (24˝′) and said piston are mounted between the wings of said U.

13. The binding as claimed in claim 12, characterized in that the first piston and the lever are bearing against oneanother with a convex surface.

14. The binding as claimed in claim 1, characterized in that the rocking lever (24) is bearing directly against the grip (Figures 21 to 23) and is bearing with a drawbar against the lateral-retention means (33′, 34′).

15. The binding as claimed in claim 14, characterized in that the body (13′) is fixed and the lateral-retention means consist of two levers (33′, 34′) mounted on fixed vertical pins (35′, 36′), one of the ends of these levers acting on said drawbar (86) on which is articulated the end of said rocking lever (24), the other end of which bears against the grip (15), the said piston (17) bearing against the said rocking lever.

16. The binding as claimed in claim 2, characterized in that said fixed stop consists of a vertical flat surface (70) of said vertical pivot (61), against which flat surface bears directly the transmission mechanism, and in that the rocking lever (24˝) is bearing against said flat surface via a sliding part (85) (Figure 15).

17. The binding as claimed in anyone of the claims 1 to 16, characterized in that the frontal face of the piston is plane and the moving part bearing against the piston has a cylindrical convex surface, with a generatrix parallel to the axis of articulation of the moving parts, in contact with the piston.

18. The binding as claimed in anyone of claims 1 to 16, characterized in that the piston has a cylindrical surface with a generatrix parallel to the axis of articulation of the moving parts and the face of the moving part bearing against the piston is plane.

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