EP1776989B1 - Safety binding - Google Patents

Abstract

The device (1) has a holding unit (2) operating a triggering action based on stresses subjected by a boot. A detection unit (3) detects the stresses subjected by the boot when it is held by the holding unit. An electronic circuit controls the triggering action of the holding unit by generating a triggering order based on a detected value of the stresses and an application time of the stresses on the boot, where the triggering action occurs when the value is higher than a real triggering threshold comprised between 50-75 percentages of a theoretical triggering threshold. An independent claim is also included for a method of pre-adjusting a safety binding of a boot on an alpine ski.

Description

The present invention relates to a safety fastening device of a boot on a gliding board, comprising releasable retaining means.

It is known in the prior art, safety fasteners comprising a front stop and a rear heel. The front stop and the rear heel hold the ski boot together, the safety fasteners trigger and release the shoe when the stop and the heel are subjected to efforts exceeding a certain threshold. The trigger threshold can be adjusted by adjusting the preload of the springs which are placed in the stop and the heel. In an essentially mechanical fixation such as that described in this document, the effective triggering of the binding is only very slightly dependent on the time of application of the forces transmitted between the boot and the ski. The lack of dependence of the trigger with respect to the time of application of the efforts can increase the risks taken by the skier. It is known that relatively large efforts that have a very short application time are safe for the skier. On the other hand, if the triggering law of the fixing device does not take into account the time of application of the forces, or in any case in a manner which is not satisfactory, as soon as a major effort is submitted, and this even for a very short time, the binding will trigger and therefore drop the skier. This type of triggering, undesirable for the safety of the skier, or even possibly dangerous, is called a nuisance tripping. This is particularly the case when the skier is traveling at high speed. In practice, to solve this problem, skiers, and especially competitors, adjust the bindings to very high values, for example DIN 15 or DIN 20. Under these conditions, we understand the risks they can take when they ski at lower speeds. On the other hand, it is also known that the human body can suffer serious damage even when subjected to weak forces, provided that these forces are applied to it for relatively long periods of time. For example, during a fall, when it is stopped, the forces to which the skier's leg is subjected may be weak, to the point of not reaching the trigger value set on the binding, but to extend beyond a few seconds. If the skier does not have the possibility of a manual release in such a situation, he risks an injury.

The document US 4,457,532 describes a method of actuating a safety binding for a ski in which the triggering threshold varies as a function of the time of application of the forces. This threshold tends, as and when, the application time increases towards a theoretical value.

The object of the present invention is to provide a safety fastening device for a boot on a gliding board which makes it possible to overcome the limitations posed by the devices known in the prior art.

The object of the invention is obtained by the provision of a safety fastening device of a boot on an alpine ski comprising releasable retaining means of mechanical, hydraulic, viscoelastic type which operate a trigger action according to the efforts to which said shoe is subjected, characterized in that the moment at short of which said triggering action is also a function of the application time, Δt, said efforts on said shoe.

Preferably the safety fastening device according to the invention comprises means for detecting the forces to which said shoe is subjected when it is held by said releasable retaining means and an electronic circuit controlling said triggering action of said releasable retaining means in generating a trip command based on the detected value of said forces and the application time, Δt, of said forces on said shoe.

Preferably, in the fixing device according to the invention, the triggering action takes place as soon as the value of the forces, E, is greater than a real trigger threshold Sr, which depends on the time of application of said forces of such so that if the application time, Δt, is greater than one second, 1 s, the actual triggering threshold, Sr (Δt), is between 50% and 75% of said theoretical triggering threshold, St; that is to say :

le seuil théorique de déclenchement, St, étant déterminé en fonction des paramètres du skieur conformément aux normes ISO.For $$\mathrm{.delta.t}>1\mathrm{s};0,75\times \mathrm{St}\ge \mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 0,5\times \mathrm{St};$$

the theoretical trigger threshold, St, being determined according to the skier's parameters in accordance with ISO standards.

On the other hand, preferably, in the fixing device according to the invention, the tripping action takes place as soon as the value of the forces is greater than a real trigger threshold Sr, which depends on the application time of a given effort such that if the application time is less than or equal to 5 hundredths of a second, 0.05 s, the actual triggering threshold, Sr, is greater than or equal to 150% of the theoretical triggering threshold, St ; that is to say :

le seuil théorique de déclenchement, St, étant déterminé en fonction des paramètres du skieur conformément aux normes ISO.For $$\mathrm{.delta.t}\le 0,05\mathrm{s};\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 1,5\times \mathrm{St};$$

the theoretical trigger threshold, St, being determined according to the skier's parameters in accordance with ISO standards.

• si le temps d'application, Δt, des efforts, E, est supérieur à une seconde, 1 s, le seuil réel de déclenchement, Sr, est compris entre 50% et 75% du seuil théorique de déclenchement, St ; le seuil de déclenchement théorique St étant déterminable pour chaque skieur en fonction de sa masse, de sa taille, de son niveau et du type de ski qu'il pratique ; c'est-à-dire :
  Pour $$\mathrm{\Delta t}>1\mathrm{s};\mathrm{0},75\times \mathrm{St}\mathrm{\ge }\mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 0,5\times \mathrm{St};$$
  
  et que
• si le temps d'application, Δt, des efforts, E, est inférieur ou égal à 5 centièmes de seconde, 0,05 s, le seuil réel de déclenchement, Sr, est supérieur ou égal à 150% du seuil théorique de déclenchement, St ; c'est-à-dire :
  Pour $$\mathrm{\Delta t}\le 0,05\mathrm{s};\mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 1,5\times \mathrm{St}$$
  

The object of the invention is also obtained by setting up a method of presetting a safety fastening of a boot on an alpine ski comprising the step of programming the triggering law of said binding which establishes the real triggering threshold, Sr, as a function of the time of application of the forces in such a way that:

• if the application time, Δt, of the forces, E, is greater than one second, 1 s, the actual tripping threshold, Sr, is between 50% and 75% of the theoretical triggering threshold, St; the theoretical trigger threshold St being determinable for each skier according to its mass, its size, its level and the type of ski that it practices; that is to say :
  For $$\mathrm{.delta.t}>1\mathrm{s};\mathrm{0},75\times \mathrm{St}\mathrm{\ge }\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 0,5\times \mathrm{St};$$
  
  and
• if the application time, Δt, of the forces, E, is less than or equal to 5 hundredths of a second, 0.05 s, the actual tripping threshold, Sr, is greater than or equal to 150% of the theoretical tripping threshold, St; that is to say :
  For $$\mathrm{.delta.t}\le 0,05\mathrm{s};\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 1,5\times \mathrm{St}$$
  

• La figure 1 est un schéma de comparaison des courbes de déclenchement de fixations de sécurité selon l'art antérieur.
• La figure 2 est une vue d'un mode de réalisation de l'invention.
• La figure 3 est une vue du graphique définissant le cadre de loi de déclenchement selon l'invention.

The invention will be better understood on reading the following description to which is appended the drawing in which:

• The figure 1 is a diagram of comparison of the tripping curves of security fasteners according to the prior art.
• The figure 2 is a view of an embodiment of the invention.
• The figure 3 is a view of the graph defining the trigger law frame according to the invention.

The International Organization for Standardization has developed an international standard for mounting, adjusting and controlling a ski / binding / shoe package (ISO 11088). This standard specifies, in particular for the use of sporting goods retailers, procedures for mounting and adjusting ski binding mechanisms.

The ISO 11088 standard defines optimal theoretical torques based on the mass, size and type of the skier. That is to say, for example for a skier whose mass is between 67 and 78 kg, it is recommended that the binding triggers and releases the shoe when the value of the torque of the forces to which the shoe is subjected is such that the component along the z axis (vertical axis) reaches 50 Nm

Manufacturers of fasteners comply with these standards and to facilitate the adjustment work by technicians, put on their products scales graduated between 2 and 20 which correspond to the presetting of the springs of the fasteners. In this case, the value of the indicator on the scale corresponds to 10% of the triggering torque along the z axis. In other words, if a fastener is "set to 5", it must trigger when the shoe is subjected to a torque of 50 N.m along the z axis (vertical axis).

Modifications are made to this adjustment as a function of the length of the sole, and according to the type of ski of the skier and which lead to an upward or downward adjustment of the value of the trigger threshold.

In the rest of this application, we will call, St, the theoretical threshold of trigger the threshold of triggering which one can determine according to the mass of the skier, the length of the sole of the shoe, and its level of practice following the recommendations of the standard.

The figure 1 shows a comparison diagram of the tripping curves of different conventional mechanical fasteners that were on the market in 2002. It contains the tripping curve of Salomon S 914, this is curve 11; that of the Marker M 9.1, curve 12 and that of the Tyrolia PS racing, curve 13. All these fixings include a front stop and a rear heel which trigger against the force of one or more springs. All fixings are set to DIN 9, ie according to ISO 11088 the theoretical tripping threshold St is approximately 90 Nm

On this diagram, are presented in abscissa the time of application of the effort in millisecond and the ordinate the effort in Newton. The results of this scheme are obtained thanks to a test machine which proceeds by applying forces at a distance of 0.9 m from an axis placed at the same position as the skier's leg.

It can be seen from this diagram that as soon as the impact time exceeds 30 ms (0.03 s), the actual tripping threshold is almost at the theoretical tripping threshold, St, which is called "the DIN" in current language.

Given the behavior of conventional mechanical ski bindings, it is well understood that the problems of inadvertent tripping, for example when the forces to which the shoe is subjected are only for a time less than 50 ms (0.05 s) are not not resolved.

The figure 2 describes an embodiment of the invention. The fixing device 1 is fixed on the ski 5 and it comprises retaining means 2 of the boot 8 which take the form of a front stop 6 and a rear heel 7. The fixing device also comprises means for detections of the forces 3. Between the detection means and the retaining means, there are decision means (not shown in the figure) which may take the form of an electronic module. It is within this decision module that the triggering law will be programmed.

Of course, the invention is not limited to a fixing device comprising a decision module of the electronic type. Other embodiments are conceivable, for example hydraulic type in the form of a hydraulic cylinder placed in parallel with the main spring of a front stop or a rear heel. When the forces are applied for a very short time, the damper blocks the movement of the spring thus preventing triggering. The hydraulic cylinder can be advantageously replaced by a viscoelastic material. In such embodiments, the detection of forces, the decision and the tripping order are indissociable because all are carried out by the main spring and the jack or the viscoelastic material.

The figure 3 is a diagram showing the control zones of the tripping law according to the invention. The tripping law Sr (Δt), represented by the curve 10 in this diagram, defines a real triggering threshold Sr as a function of the application time of the forces Δt.

ou bien, en utilisant une autre typographie : $$\mathrm{Sr}\left(\mathrm{\Delta t}\right)\mathrm{=}\mathrm{a}\mathrm{+}\exp \left[\left(\mathrm{b}\mathrm{-}\mathrm{\Delta t}\right)\mathrm{/}\mathrm{c}\right]$$

The triggering law, Sr (Δt), is of exponential decay type which is expressed mathematically in the following form: $$\mathit{Sr}\left(\mathrm{\Delta }\begin{array}{}\end{array}t\right)=\mathrm{at}+e^{\frac{-\mathrm{.delta.t}+b}{\mathrm{vs}}}$$

or, using another typography: $$\mathrm{Sr}\left(\mathrm{.delta.t}\right)\mathrm{=}\mathrm{at}\mathrm{+}\exp \left[\left(\mathrm{b}\mathrm{-}\mathrm{.delta.t}\right)\mathrm{/}\mathrm{vs}\right]$$

The parameters a, b and c are chosen so that in any event, the tripping law remains framed by the zones defined by the present invention.

In particular, if the application time is greater than one second, 1 s, the real triggering threshold, Sr, is between 50% and 75% of said theoretical triggering threshold, St; that is to say :

For $$\mathrm{.delta.t}>1\mathrm{s};\mathrm{0},75\times \mathrm{St}\mathrm{\ge }\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 0,5\times \mathrm{St}$$

On the other hand, if the application time, Δt, of forces is less than or equal to 5 hundredths of a second, 0.05 s, the actual triggering threshold, Sr, is greater than or equal to 150% of the theoretical threshold of tripping, St; that is to say :

For $$\mathrm{.delta.t}\le 0,05\mathrm{s};\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 1,5\times \mathrm{St}$$

The invention also aims to protect a method of presetting a safety binding of a boot on an alpine ski. This method consists in the programming of a triggering law, Sr (Δt), of said fixation which institutes the real triggering threshold, Sr, as a function of the application time, At of the forces E, this law being of the decay type exponential: Sr (Δt) = a + exp [(b - Δt) / c]; where the parameters a, b and c are set according to its mass, its size and the type of ski it practices and chooses, in any case in such a way that

etFor $$\mathrm{.delta.t}>1\mathrm{s};\mathrm{0},75\times \mathrm{St}\mathrm{\ge }\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 0,5\times \mathrm{St};$$

and

For $$\mathrm{.delta.t}\le 0,05\mathrm{s};\mathrm{Sr}\left(\mathrm{.delta.t}\right)\ge 1,5\times \mathrm{St}$$

Of course, the invention is not limited to a programming law that is exactly of the exponential type, since approximations of such a law will also be covered by the present invention insofar as the triggering law remains framed in the zones. defined by the present invention.

NOMENCLATURE

• 1- fixing device
• 2- retaining means
• 3- detection means
• 4- calculation module
• 5- ski
• 6- stop before
• 7- back heel
• 10- trigger law Sr (Δt)
• 11-law trigger Solomon S 914
• 12- trigger law Marker M 9.1
• 13- trigger law Tyrolia PS racing

Claims (6)

1. Safety binding device (1) for binding a boot on an alpine ski comprising releasable retaining means (2) of the mechanical, hydraulic, viscoelastic type, which actuate a release as a function of the forces to which said boot is subjected and comprise means for detecting the forces to which said boot is subjected when it is retained by said releasable retaining means (2), characterized in that it further comprises an electronic circuit controlling said release action of said releasable retaining means (2) by generating a release command as a function of the detected value of said forces and of the time of application Δt of said forces to said boot, and in that the release action occurs as soon as the force value is greater than an actual release threshold Sr, which is dependent upon the time of application Δt of a given force, such that the time of application is greater than one second 1 s, the actual release threshold Sr ranges between 50% and 75% of said theoretical release threshold, St, whereby: $$\mathrm{\Delta t}>1s;0.75\mathrm{x\; St}\ge \mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 0.5\mathrm{x\; St};$$

   

   
   the theoretical release threshold St being determined as a function of the skier's parameters in conformance with the ISO 11088 standards.
2. Binding device according to claim 1, characterized in that the release action occurs as soon as the force value is greater than an actual release threshold Sr, which is dependent upon the time of application of a given force, such that the time of application is less than or equal to 5 hundredths of a second 0.05 s, the actual release threshold Sr is greater than or equal to 150% of the theoretical release threshold St, whereby: $$\mathrm{\Delta t}\le 0.05s;\mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 1.5\mathrm{x\; St};$$

   

   
   the theoretical release threshold St being determined as a function of the skier's parameters in conformance with the ISO standards.
3. Binding device according to one of claims 1 to 2, characterized in that the release principle, which defines the actual release threshold as a function of the time Sr (Δt), is of the exponential decrease type: Sr(Δt) = a + exp [(b - Δt) / c ]; where a, b, and c are parameters.
4. Method for pre-adjusting a boot safety binding on an alpine ski comprising the step of programming the release principle of said binding, which establishes the actual release threshold Sr as a function of the time of application of the forces, such that if the time of application Δt of the forces is greater than one second 1 s, the actual release threshold Sr, ranges between 50% and 75% of the theoretical release threshold St; the theoretical release threshold St can be determined for each skier as a function of the skier's weight, height, and skiing type, whereby: $$\mathrm{\Delta t}>1s;0.75x\mathrm{St}\ge \mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 0.5\mathrm{x\; St}$$

   
5. Method for pre-adjusting a boot safety binding on an alpine ski according to claim 4, characterized in that said release principle is programmed such that if the time of application Δt of the forces is less than or equal to 5 hundredths of a second 0.05 s, the actual release threshold Sr is greater than or equal to 150% of the theoretical release threshold St, whereby: $$\mathrm{\Delta t}\le 0.05s;\mathrm{Sr}\left(\mathrm{\Delta t}\right)\ge 1.5\mathrm{x\; St};$$

   
6. Method for pre-adjusting a boot safety binding on an alpine ski according to one of claims 4 or 5, characterized in that said release principle, which defines the actual release threshold as a function of the time Sr (Δt), is of the exponential decrease type: Sr(Δt) = a + exp [(b-Δt) / c]; where a, b, and c are parameters set as a function of the skier's weight, height, and skiing type.

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