US3919563A

US3919563A - Controllably self-releasable safety fastener and method of unlocking same

Info

Publication number: US3919563A
Authority: US
Inventors: Dominique Jean Lautier; Lucien Louis Maeder; Pierre Edmund Mayer
Original assignee: Agence National de Valorisation de la Recherche ANVAR
Current assignee: Bpifrance Financement SA
Priority date: 1973-04-10
Filing date: 1974-04-08
Publication date: 1975-11-11
Anticipated expiration: 1992-11-11
Also published as: DE2416424A1; DE2416424C3; CH600907A5; FR2266527A2; FR2225185B1; ATA287574A; FR2225185A1; AT337058B; FR2266527B2; DE2416424B2

Abstract

A safety fastener with controlled automatic release upon occurrence of given critical outside influences, with means for sensing and transducing at least one force applied to at least one fastening element, comprising means for integrating with respect to time the signal from the sensing and transducing means, means for comparing this signal with a given least reset value for the integrating means when the signal is below this least value, means for comparing the signal integral to a given maximum value and fastener-unlocking means operated when the integral is above said given maximum value.

Description

United States Patent Lautier et a1.

1 1 Nov. 11, 1975 CONTROLLABLY SELF-RELEASABLE SAFETY FASTENER AND METHOD OF UNLOCKING SAME Inventors: Dominique Jean Lautier. Jouy en Josas'. Lucien Louis Maeder', Pierre Edmond Mayer, both of Paris, all of France Agence Nationale de Valorisation de la Recherche (ANVAR), Neuilly sur Seine. France Filed: Apr. 8, 1974 Appl. No: 458.590

Assignee:

Foreign Application Priority Data Apr. 10. 1973 France 7312931 US. Cl....... 307/119; 280/1135 M. 340/248 A Int. Cl.'- A63C 9/00 Field of Search 307/119. 324/130. 76 A; 340/248 A; 280/1135 M. 11.35 T. 11.35 A. 11.35 D

156] References Cited UNlTED STATES PATENTS 3.105.231) 9/1963 Maclnqre 324/130 UX 3.559.788 1/1971 Jensen 307/119 X 3.587.078 6/1971 Eichmann 340/248 A 3.671.054 6/1972 Mittelstadt 2811/1135 M Primary Examiner-Herman Hohauser [5 71 ABSTRACT A safety fastener with controlled automatic release upon occurrence of given critical outside influences. with means for sensing and transducing at least one force applied to at least one fastening element. comprising means for integrating with respect to time the signal from the sensing and transducing means. means for comparing this signal with a given least reset value for the integrating means when the signal is below this least value. means for comparing the signal integral to a given maximum value and fastener-unlocking means operated when the integral is above said given maximum value.

27 Claims, 18 Drawing Figures U.S. Patent Nov. 11,1975 Sheet 1 of6 3,919,563

Sheet 3 of 6 Nov. 11, 1975 US. Patent U.S. Patent Nov. 11, 1975 Sheet 4 016 3,919,563

U.S. Patent Nov. 11,1975 Sheet5of6 3,919,563

w W R gm tfa Sheet 6 of 6 3,919,563

US. Patent Nov. 11, 1975 LEM.

CONTROLLABLY SELF-RELEASABLE SAFETY FASTENER AND METHOD OF UNLOCKING SAME The present invention relates generally to a controllably self-releasable safety fastener device or like latch contrivancc with automatic controlled or controlresponsive release or like self-acting actuationresponsive or operated opening comprising means for locking a member to be released upon the occurrence or under the action of predetermined critical outside or extraneous influences as well as to a method or process of unlocking such a fastener or latch.

This kind of fastener and this method of unlocking may be used in many fields such as automative engineering, automobile vehicles and cars, aviation and aircraft every time securing devices are used for locking a member adapted to be automatically and controllably or operatively opened or released by the occurrence or under the action of predetermined critical extraneous influences. In particular the fastener according to the invention may be a safety binding appliance or like safety attachment means mounted on a ski and normally enabling to lock or secure the boot or shoe of a ski-runner and to release, free or disengage same upon the occurrence or under the influence of critical extraneous influences such as the force exerted upon the foot or leg of the ski-runner when a fall happens.

Already known safety bindings for skis work unsatisfactorily as on the one hand they are opened or released too slowly in case of very heavy and short shocks and on the other hand they are not very faithful or they show little fidelity, i.e. they are not caused to be released in every case for the same magnitude or strength of force.

The principle of operation of these prior art fasteners consists generally in measuring a force or torque exerted upon an element of the fastener and comparing the value of the measurement with a predetermined maximum value for triggering or not the release or opening of the fastener. This principle is wrong since it necessarily assumes that it is the forces applied on the foot or leg of a ski-runner which are the cause of the fractures of bones. On the contrary, it has become apparent that the fractures of the bones are brought about by the integral with respect to time of the forces applied, i.e. by the momentum or impulse applied to the foot or leg of the ski-runner,

Another inconvenience of the known prior art fasteners is the fact that in general the release devices are mechanical tripping or disengaging devices exhibiting little fidelity and high inertia the power source of which is the inertia of the skirunner himself.

In order to avoid all these disadvantages the invention provides a safety fastener with controlled automatic release or opening operated upon the occurrence or under the action of predetermined critical extraneous influences, including means for sensing or detecting and transducing at least one force applied to at least one element of the fastener and characterized in that it comprises means for integrating with respect to time the signal output from the sensing and transducing means, means for comparing the magnitude of this signal to a predetermined minimum valve and for resetting the integration means when the signal is below this minimum valve, means for comparing the signal integral to a predetermined maximum value and fastener unlocking means actuated when the integral is above said maximum value.

Thus the fastener according to the invention actually uses the momentum that the foot or leg of the skirunner has undergone directly or indirectly and the magnitude of the momentum sustained is compared with a predetermined maximum value beyond which the fastener has to be opened or released to avoid a fracture, wound or like injury or hurt.

According to another characterizing feature of the invention said unlocking means comprise a pyrotechnical charge and ignition means for firing said charge when the integral is higher than said maximum value.

Thus is obtained a release or opening of the fastener much quicker than by means of a mechanical opening system for instance of the spring-loaded or resiliently biased type.

The invention relates further to a method of automatically unlocking a safety fastener upon the occurrence or under the action of predetermined critical extraneous influences, comprising the steps of sensing or detecting and measuring at least one force applied to at least one element of the fastener and comparing this measured force to a predetermined least or minimum value, said method being characterized in that it also consists in integrating the force with respect to time, comparing the magnitude of the integral with a predetermined maximum value, automatically resetting the integral when said force is lower than a predetermined minimum value and automatically unlocking said fas tener when the integral in case of a force higher than that minimum value is above said predetermined maximum value.

Owing to the invention a safety fastener is thus unlocked only when the integral of a force, i.e. the momentum, is higher than a predetermined maximum value for a force above a predetermined minimum value, i.e. the fastener will be unlocked automatically for a constant or steady magnitude of momentum, whether a very violent, strong or heavy or a very fierce effort is involved or an effort of average, mean or medium strength extending in time as for instance in the case ofa slow twist of large amplitude, i.e. a torsion of large extent proceeding slowly in time.

According to a further characterizing feature of the method of the invention the fastener is unlocked by firing or igniting a pyrotechnical charge. Thereby is available a power source enabling to unlock the fastener almost instantaneously and which delivers or supplies a very significant amount of energy for a device of very small bulk and weight.

The invention will be better understood and further objects, characterizing features, details and advantages thereof will appear more clearly as the following ex planatory description proceeds with reference to the accompanying drawings given by way of non-limiting example only illustrating various forms of embodiment of the invention and wherein:

FIG. 1 diagrammatically shows an electric circuit of a system for releasing a safety fastener according to the invention;

FIG. 2 diagrammatically shows an alternative embodiment or modification of the system depicted in FIG. 1;

FIGS. 3 and 4 show in more detail parts of the circuit depicted in FIG. 2;

FIG. 5 diagrammatically shows a graphical chart with curves illustrating the variations of the force and momcntum sensed by a release system according to the invention and plotted against or as a function of time;

FIGS. 6 and 7 diagrammatically show as block diagrams alternative embodiments of the electrical circuits of the release arrangements according to the invention;

FIG. 8 is a fragmentary perspective view of a safety fastener according to the invention fitted as a binding on a ski;

FIG. 9 is a top view of the rear part or back portion of the binding shown in FIG. 8',

FIG. I is a view in longitudinal section of the portion of the binding shown in FIG. 9',

FIG. 11 is a top view of the front portion of the binding shown in FIG. 8;

FIG. I2 is a view in longitudinal section of the portion of binding shown in FIG. II;

FIG. 13 is a top view of an alternative embodiment of the rear portion of a ski-binding according to the invention;

FIG. 14 is a view in longitudinal section of the portion of binding shown in FIG. 13',

FIG. 15 is a top view of another alternative embodiment of a rear portion of a ski-binding according to the invention;

FIG. 16 is a view in longitudinal section of the portion of binding shown in FIG. 15;

FIG. 17 is a top view of still another modification of a rear portion of a ski-binding according to the invention; and

FIG. 18 is a view in longitudinal section of the back part of the binding shown in FIG. 17.

There has thus been shown in the drawings and more particularly in FIG. I an electrical circuit of the means for releasing a safety fastener such as a ski-binding which embodies the process according to the invention.

As already stated this process consists in sensing or detecting and measuring at least one force applied onto at least one element of the fastener and then integrating this force with respect to time. comparing the magnitude or strength of the force to a predetermined mini mum value, automatically resetting the integral when the force is lower than the predetermined minimum value, comparing the magnitude of the integral to a predetermined maximum value and unlocking the fastener when the integral is higher than the predetermined maximum value for a force above the predetermined minimum value.

The circuit embodying this method therefore comprises means for sensing or detecting and measuring at least one force applied to one element of the fastener. these sensing and measuring means including for instance strain gauges l adhesively glued or stuck onto a deformable element of the fastener and for example connected in bridging relationship between the ground 2 and a supply voltage a. The output of these sensing and measuring means is connected to the input of am plifying means A comprising for instance a pair of series connected

operational amplifiers

3 and 4 the output of which is connected through an absolute value setting circuit ABS to integrating means I.

The absolute value setting circuit ABS comprises an operational amplifier 5 the negative input of which is connected to the output of the amplifying means A and the positive input of which is connected to the ground 2. The output of the operational amplifier 5 is connected to the anode of a diode 7 and to the cathode of a diode 8. The negative input of the operational ampli fier S is connected through a resistor R, to the anode of the diode 8 and through a resistor R to the cathode of the diode 7. A resistor R connects the cathode of the diode 7 to the negative input of a second operational amplifier 6 the positive input of which is connected to the anode of the diode 8. A capacitor and a resistor are connected in parallel between the negative input of the operational amplifier 6 and the output of the latter.

The integrating means I comprise an operational amplifier 9 the negative input of which is connected to the output of the operational amplifier 6, and a resistor R and a capacitor C. are connected in parallel between the negative input and the output of the operational amplifier 9. The positive input of the latter is connected to the ground 2 through a resistor. The drain b and the source a of a field effect transistor T, are mounted across a capacitor C, as shown. The gate of this field effect transistor T is connected through a diode I0 to the output of an operational amplifier II the positive input of which is connected to the output of said operational amplifier 6 and the negative input of which is connected through a resistor to the intermediate point of a variable resistor R mounted between the ground 2 and a negative voltage supply Va. The intermediate point of the variable resistor R defines together with the ground 2 a reference voltage Vrn which corresponds to the predetermined minimum threshold value of the force.

The variable resistor R the operational amplifier II and the field effect transistor T thus define means for comparing the sensed signal with a predetermined least or minimum value for resetting the integrating means when the sensed signal is lower than the predetermined minimum value as will be set forth hereinafter more in detail.

The output of the operational amplifier 9 is connected to the positive input of an operational amlifier 12 the negative input of which is connected through a resistor to the intermediate point of a variable resistor R mounted between the ground 2 and the positive voltage supply +Va. The output of the operational amplifier I2 is connected to the trigger-gate of a thyristor T the anode of which is connected to the positive voltage supply +Va and the cathode of which is connected through a pyrotechnical device 15 to the negative voltage supply Va. A capacitor C, is connected in parallel between the negative voltage supply Va and the anode of thyristor T Thus the operational amplifier 12 and the variable resistor R form the means for comparing the signal integral to a predermined maximum value V which is defined between the ground and the intermediate point of the variable resistor R and the thyristor T the pyrotechnical device 15 and the capacitor C form the means for unlocking the fastener which are operated when the signal integral exceeds the predetermined maximum value as will be explained hereinafter more in detail.

This release system operates in the following manner:

The strain gauges I will be assumed to be adhesively glued or stuck on either side of a thin strip or lamination deformable through bending or flexure in either direction. The signal obtained at the output of the bridge-like connection arrangement of the strain gauges I is highly amplified by the operational amplificrs 3 and 4 and then processed by the absolute value setting circuit ABS which enables to obtain from the output of the operational amplifier 6 a signal having always the same sign whatever the positive or negative polarity of the output signal from the operational amplifier 4 may be. This output signal V from the operational amplifier 6 is fed or applied on the one hand to the negative input of the operational amplifier 9 of the integrating means I and on the other hand to the positive input of the operational amplifier 11 wherein it is compared with the reference voltage Vm corresponding to the predetermined minimum value of the effort. When the voltage V which has the same sign as the voltage Vm is lower than that voltage Vm the output of the operational amplifier 11 has a potential substantially equal to +Va so that the field effect transistor T is turned on or becomes conducting and the integration capacitor C is discharging steadily. There is thus provided in this case an automatic resetting of the integration means I.

On the contrary when the voltage V is higher than Vm, the potential at the output of the operation amplifier 1] becomes equal to Va thereby resulting in turning off the field effect transistor T so that the integration capacitor C can no longer discharge. There is then integration ofthe signal V within the integrating means I. The signal VI appearing at the output of the operational amplifier 9 is then fed to the positive input of the operational amplifier 12 where it is compared to the reference voltage V When the signal VI is lower than the voltage V the voltage of the operational amplifier 12 is substantially equal to Va, so that the thyristor T is turned off or non-conducting. When on the contrary the voltage VI becomes higher than V the potential at the output of the operational amplifier 12 is substantially equal to +Va and the thyristor T is turned on or becomes conductive thereby causing at the same time the capacitor C to discharge into the pyrotechnical device l5 and the unlocking of the fastener to take place.

an illustrative example of the shapes of the curves V and VI plotted against the time I has been shown in FIG. 5. It may be seen that at the time t,. the voltage V is below the threshold Vm so that the voltage VI is zero; between t, and t the voltage V is higher than Vm and there is an integration but VI remains below V Between t and t the voltage V is below Vm thereby annulling VI and then between and t the voltage V is higher than Vm and an integration takes place until the time t, at which VI reaches the value V thereby causing the fastener to be unlocked. It is assumed that the fastener has been locked again some time after release thereof and that the voltage V then varies while remaining lower than Vm until the time After a time later than i V is higher Vm and varies slowly. There is integration from and the voltage Vl increases regularly up to V which it reaches at the time thereby causing the fastener to be unlocked.

In the first embodiment of the release system shown in FIG. I, operational amplifiers have been used which offer the advantage of being perfectly symmetrical so that the different causes of drift of the components as a function of temperature for example are compensating or balancing by themselves.

An alternative embodiment of this circuit is shown in FIGS. 2 to 4.

In these Figures the means for sensing and transducing the effort applied to the leg or foot of the ski-runner comprise a strain gauge I connected between the ground 2 and a dc. voltage source 20 through a resistor. An operational amplifier A amplifies the measure signal corresponding to the sensed effort and feeds same to a high pass filter F consisting of a capacitor C coupled to the output of the operational amplifier A and a pair of resistors connecting the terminals of the capacitor C to the ground. The output of the filter F is connected to an integrating circuit comprising an operational amplifier A, the input of which is connected to the output of filter F and the other input of which is connected to the ground 2 as well as a capacitor C connected between the first input and the output of the operational amplifier A A circuit I3 for comparing the value of the integral to a predetermined maximum value and for firing or igniting the pyrotechnical device 21 is connected between the ground 2 and the output of the operational amplifier A A circuit B for comparing the magnitude of the signal obtained at the output of the operational amplifier A with a predetermined critical minimum value is also connected between the output of the operational amplifier A and the ground 2 and receives the signal from the output of the amplifier A These circuits B and B are shown more in detail in FIGS. 3 and 4, respectively.

The circuit B consists essentially ofa Schmitt trigger circuit consisting of NPN-type transistors T and T respectively, the interconnected emitters of which are biased to a predetermined value by dividing means constituted by two resistors P and P this predetermined value corresponding to the maximum value set for the magnitude of the integral of the measured effort. The capacitor C, has been shown connected in broken lines between the input of this circuit B and the ground 2 as the first aforesaid input of the operational amplifier A corresponds to a fictive ground since in operation the operational amplifier A has a nearly infinite voltage gain. The capacitor C, may therefore be considered as connected between the ground and the input of circuit B The input of the circuit B is connected to the base of the transistor T the collector of which is connected through a resistor to the base of the transistor T Between the collector of the latter and the source of direct current 20 is connected a relay 22 comprising a normally open contact 23. The making or closing of this contact 23 results in the closing or completing of a supply circuit feeding a winding 24 connected between the direct current source 20 and the ground and which forms the primary winding of a transformer the secondary winding of which consists for instance of another winding 25 fully embedded in a blasting cap or primer 26 made from detonating material such as explosive powder forming together with the winding 25 said pyrotechnical device 21. The winding 25 may be closed on itself or comprise a spark gap 27 allowing the firing or igniting of the charge 26 by priming or flashover through field effect.

The circuit B shown in detail in FIG. 4 essentially comprises a Schmitt trigger circuit consisting of two PNP-type transistors T and T the interconnected emitters of which are biased to a predetermined value for instance by means of dividing means P P this predetermined value corresponding to the minimum lower value set for the measured effort. As previously the connection arrangement of the capacitor C of the integrating circuit has been shown in broken lines between the ground 2 and the collector of transistor T connected to the output of the operational amplifier A The Schmitt trigger circuit consisting of the transistors T and T is used for operating by means of the transistor T the discharge of the integrating capacitor C when the measured effort becomes lower than the predetermined minimum value.

The operation of this circuit shown in FIGS. 2 to 4 is the following:

An effort is sensed and measured by the strain gauge 1 and then amplified by the operational amplifier A The filter F provided at the output of the operational amplifier A, enables to remove the direct current component from the amplified signal. An integration of this signal with respect to time is achieved by means of the amplifier A and the capacitor C The output signal from the amplifier A which corresponds to the integral of the measured effort with respect to time and accordingly to the momentum is applied to the base of the transistor T which is therefore turned off as long as this signal is below the biasing voltage of the transistors T and T Under such conditions the transistor T is conducting, the relay 22 is for instance engerized and the contact 23 is open. When the output signal from A is higher than the biasing voltage of the transistors T and T, the transistor T becomes conducting or is turned on and the transistor T is turned off thereby causing the relay 22 to rest and closing the contact 23. The primary winding 24 is then energized and causes the charge 26 to be fired through induction within the secondary winding 25 and priming through field effect by means of the spark gap 27.

At the same time the circuit B is driven by the signal V from the output of the amplifier A,. As long as this signal V is higher than the biasing voltage of the transistors T and T the transistor T remains turned off and the transistor T, is conducting. As soon as the signal V becomes lower than the bias voltage of these two transistors, the transistor T becomes conducting or is turned on and the transistor T is turned off. Then there appears a voltage step on the resistance of the collector of the transistor T this step being applied to the base of the transistor T and rendering the latter conducting or turning same on. The capacitor C is then discharge into the collector-emitter space of the transistor T and the resetting of the integration circuit is thereby achieved.

At the outputs of the operational amplifiers A and A are therefore obtained the same kind of curves as those shown in FIG. 5.

It should be pointed out that in the circuit shown in FIG. 1, it is very easy to change the values Vm V representing the predetermined minimum value of the effort and the predetermined maximum value of the integral, only be adjusting the variable resistors R and R,,. In the circuit shown in FIGS. 2 to 4, it is also possible to provide circuits or plug-in electronic components for the purpose of adjusting the bias voltages of the transistors T and T, on the one hand and T and T on the other hand and therefore to impart various values to the lower limit of the signal and to the upper limit of the integral.

In FIGS. 6 and 7 there is diagrammatically shown as block diagrams two alternative embodiments of the release systems according to the invention which enable to sense and to measure two efforts applied to the leg or foot of the ski-runne r, such for instance as a twisting effort and a tensile or pulling effort.

In FIG. 6, each effort E F is sensed and measured separately by means 30, 31 respectively, and the output signal from these

means

30, 31 is then fed to the input of amplifying means 32, 33, respectively. The output signal from the amplifying means 32 is fed to means 34 for comparison to a predetermined minimum value and for resetting integrating means 35 the input of which is also connected to the output of the amplifiying means 32. The output of the integrating means 35 is connected tothe input of means 36 for comparing the integral with a predetermined upper value and the output of the means 36 is itself connected to the input of the unlocking means 37.

Likewise the output of the amplifying means 33 is connected to the input of means 38 for comparison of the signal with a predetermined minimum value and for resetting integrating means 39 the input of which is also connected to the output of the amplifying means 33. The output of the integrating means 39 is connected to means 40 for comparing the integral with a predetermined maximum value, the output of the comparator means 40 being connected to the input of the unlocking means 37.

In FIG. 7, both efforts F and F are sensed and amplified separately by the

means

30 and 32, and 31 and 33, respectively. The outputs of the amplifier means 32 and 33 are connected each one to an input of a mixing circuit 41 the output of which is connected to the input of means 42 for comparing the signal to a predetermined minimum value and for resetting integrating means 43 the input of which is also connected to the output of the mixing circuit 41. As previously, the output of the integrating means 43 is connected to unlocking means through the medium of means 44 for comparing the integral with a predetermined maximum value. In this form of embodiment of FIG. 7, the output signal from the mixing circuit 41 corresponds to a combination of the output signals from the amplifying means 32 and 33, and this combination may be linear for instance.

It should be noted that the unlocking

means

37, 45 used in the alternative embodiments of FIGS. 6 and 7 may be py rotechnical devices comprising a blasting cap or primer made from detonating material such as explosive powder, of the kind shown in FIG. 3, of they may be of the magnetic ally operated type and comprise for instance a magnetic or electro-magnetic circuit the magnetic saturation or desaturation of which causes the fastener to be unlocked by exerting a pulling or repelling force upon a fastener locking element.

In FIGS. 8 to 18 there has been shown various forms of embodiment of a skibinding according to the invention.

This ski-binding the general lay-out of which is shown in FIG. 8 is fitted onto a ski and comprises a front stop member or abutment 51 adapted to engage and to hold the toe of the boot of the ski-runner and a rear stop member or back abutment 51 adapted to engage and to hold or grip the heel portion of the boot of the ski-runner.

The front stop member or abutment grip 51 as shown more in detail in FIGS. 11 and 12 is rotatably mounted about a vertical pivot 53 integral with the ski 50. The front end of this stop member 51 is made integral or fast with one end 50 of a bending strip or flexing blade 55 which is arranged lengthwise in a vertical plane at right angles to the plane of the ski 50. The end 54 of the bending strip 55 is for instance force fitted and held in a vertical slot ofthe front end ofthe stop member 51. The opposite end 56 of the bending strip 55 is guided in a vertical longitudinal slot 57 ofa part 58 while being kept bearing against a pair of vertical projections 59 of the inner walls of the slot 57. The part 58 is movable longitudinally on the ski 50 with respect to the strip 55 by means of a pivot 60 the bottom end of which carries an eccentric snug, pin or stub 61 which extends into a hole of a supporting plate 62 made fast with the ski 50. The member 58 is guided when travelling lengthwise between two raised or upturned flanges 63 of the plate 62. Thus through rotation of the pivot 60 it is possible to displace the member 58 longitudinally with respect to the bending strip 55 and therefore to increase or decrease that portion of the strip 55 which lies between the projections 59 and the front stop member 51. The deformation of the strip 55 through bending which is caused by the swinging of the front stop member 51 about the pivot pin 53, is sensed or detected by means of strain gauges 64 adhesively bonded onto both major faces or large sides of the strip 55. These strain gauges 64 are connected by conductors or like lead wires 65 to the electrical release system diagrammatically shown as a block 66 behind or at the rear of the binding.

Likewise the rear portion of the binding which is shown in greater detail in FIGS. 9 and 10 comprises a bending strip or flexing blade 70 on both faces or large sides of which are adhesively bonded strain gauges 71 connected to the electric release system 66. The rear end of the strip 70 is bearing upon an abutment 72 adjustable in position with respect to the end of the strip 70 the other end of which is integral with a clevis-like or yoke-shaped portion 73 comprising a pair of upstanding side cheeks between which the rear stop member 52 is pivotally connected about a horizontal transverse pin 74. The yoke-shaped part 73 is in turn pivotally connected about a horizontal transvers pin 75 located ahead of the pin 74 between two legs or tabs of a stationary part 76 secured to the ski 50 and carrying for instance the abutment 72.

The yoke-shaped part 73 also carries at its upper portion a horizontal transverse pin 77 about which is pivotally fitted an arm 78 the upper portion of which may co-operate with a lever 79 also pivotally connected about the pin 77 and the lower portion of which is pivotally connected onto one end of an arm 80 the other end of which is pivotally connected to the rear stop member 52.

The yoke-shaped part 73 also carries a pyrotechnicai actuating device 81 which is mounted in screw threaded engaging relationship into a screw threaded portion of the part 73 and which is connected through a conductor or like lead wire 82 to the electric release system 66. This pyroteehnical actuating device 81 is of a type known per se and it comprises a charge of detonating material such as explosive powder accommodated or housed inside of a cylinder which also contains a piston the rod 82 of which extends forward and out of the device 81. In inoperative position the rod 82 assumes the position shown in FIG. 10 and also forms a rest or bearing for the arms 78 and 80 in the locked position of the binding.

It should be noted that the part 73 extends forward with a plate 83 adapted to lie under the heel of the boot of the ski-runner which when the binding is locked is held against motion between the plate 83 and a jaw 84 secured to the rear stop member 52. The position in height of the jaw 84 in relation to the stop member 52 is adjustable so that it may be adapted to boots of various sizes.

The operation of this rear portion of the binding is the following:

It should at first be assumed that the binding is locked on the boot of the ski'runner as shown in FIG. 10. When the ski-runner is for instance falling forward a pulling effort T is exerted upon the rear stop member 52 as shown in FIG. 10. This rear stop member 52 is locked in position with respect to the part 73 by means of the arms 78 and 80 which also serve to transmit the effort T to the part 73. The latter is therefore swung clockwise as seen in FIG. 10 about its pivot pin and it causes the flexing strip 70 to be bent downwards The strain gauges 71 record a deformation or distorsion which is processed by the electrical system 66 in the manner previously described. When the integral of the detected signal becomes higher than a predetermined maximum value for a signal higher than a predetermined minimum value, the electrical system 66 initiates the firing of the actuating device 81 so that the piston rod 82 is moved forward and carries along or drives the arms and 78 during its motion. The rear stop member 52 is then raised or lifted upwards and is disengaged from or releases the boot of the ski-runner.

Advantageously, the piston rod 82 may be kept in its forward or front end position as long as the charge of detonating material of the actuating device 81 has not been replaced. It is thus impossible to lock again the binding onto the boot of the ski-runner as long as the actuating device 81 has not been reset or brought back to operating condition. When this has been effected it suffices to pull the end of the lever 70 upwards for moving the arms 78 and 80 back to an aligned registering condition in the position shown in FIG. 10 hence for clamping the rear stop member 52 onto the heel of the boot of the ski-runner.

It should likewise be noted that the unlocking of the binding by means of the actuating device 81 may also be operated from an effort exerted upon the front stop member 51, said effort being sensed by the strain gauges 64 and transmitted to the electric system 66. The latter may advantageously be of the type shown in FIG. 6 or in FIG. 7.

An alternative embodiment of the rear portion of the binding as shown in FIGS. 13 and 14 and differs from the embodiment shown in FIGS. 9 and 10 by the shape of the locking lever and of the rear stop member. in FIGS. 13 and 14, the rear stop member 85 is as before pivotally connected about a pivot shaft 86 secured to a yoke-shaped or clevis-like part 87 comprising a backward extension 88 forming a bending strip provided with strain gauges 89 and a forward extension 90 on which rests the heel of the boot of the ski-runner. A locking lever 91 is pivotally connected at 92 onto the yoke-shaped part 87 and carries at its lower end a roller 93 riding on a slanting ramp or track provided by the rear stop or grip member 85. The pyrotechnical actuating device 81 is as before carried by the yoke-shaped part 87 and the piston rod 82 forms in normal position thereof an abutment or rest for the locking lever 91. When the device 91 is operated the piston rod 82 moves the lever 91 forward thereby freeing the rear stop or grip member 85 and therefore unlocking the binding. When the device 81 is again in operative con dition or working order it is possible by means of the lever 91 to lock the rear stop or grip member 85 onto the heel of the boot of the ski-runner as shown in FIG.

FIGS. and 16 illustrated another alternative embodiment of the rear portion of the binding which enables a selfacting locking of the binding when the skirunner is inserting his boot into the binding. This alternative embodiment comprises as the preceding ones a yoke-shaped part 95 formed with a backward extension 96 constituting a bending strip on which are mounted strain gauges 97 and with a forward extension 98 adapted to be located under the heel of the boot of the ski-runner. The rear stop member or grip 99 is pivotally connected about a horizontal transverse shaft 100 of a second yoke-shaped or clevis-like part 101 pivotally connected into the first yoke-shaped part 95 about a horizontal transverse pin 102. This part 101 supports a pyrotechnical actuating device 81 like those described in the preceding forms of embodiment. The piston rod 82 of the device 81 forms a rest or bearing for a part 103 mounted for rotation about a pin 104 secured to the part 101 and which is provided with a drawback or return spring 105 urging it back towards the actuating device 81. This part 103 forms a cam for locking the rear stop member or grip 99 onto the heel of the boot of the ski-runner by hearing with its upper end against a backward extension 106 of the rear stop member or grip 99. A locking lever 107 is pivotally connected at its end portion to the yokeshaped part 85 and extends with its front end underneath the heel of the boot of the ski-runner as shown in FIG. 16. In its middle portion this lever 107 comprises an elongated hole 108 forming a guide slot for a horizontal transverse pin 109 secured to the yoke-shaped part 101. The

yokeshapcd part

95 and 101 are connected at their upper portions by a knuckle-joint or toggle-lever 110 consisting of a pair of pivotally

interconnected lever arms

111 and 112 which are pivotally connected at their opposite ends. respectively, to the part 101 and to the part 95. It should also be noted that the rear stop member or grip 99 is provided with a drawback or return spring 113 urging it to swing back in the counterclockwise direction as seen in FIG. 16.

The operation of this alternative embodiment of the rear portion of the binding is the following:

When the binding is unlocked, the yoke-shaped portion 101 has swung in the clockwise direction in relation to the part 95 about its shaft 102, the locking part 103 has rocked or tilted about its shaft 104 in the direction opposite or away from the device 81 and the rear stop member or grip 99 has slightly rotated in the clockwise direction under the action of the drawback spring 113. Owing to the swinging ofthe part 101 about the shaft 102, the front portion of the lever 107 has been slightly lifted or raised. When the ski-runner inserts his boot into the binding. he presses with the heel onto the front end of the lever 107 thereby swinging the part 101 in the counterclockwise direction about the shaft 102 and causing the rear stop member or grip 99 to be locked onto the heel of the boot. The rear stop member or grip 99 is kept in position by the locking part 103. The lever arms 11] and 112 are then in aligned or substantially registering position as shown in FIG. 16 and are fully locking the binding.

In case of release through the electrical system 66, the piston rod 82 is caused to push the locking part 103 against the action of the drawback spring thereby disengaging the rear stop member or grip 99 and allowing same to swing about the shaft 100 under the action of the drawback spring 113. The boot ofthc ski-runner is then frccd.

Another alternative embodiment of the rear stop member or grip of the binding is shown in FIGS.17 and 18, the difference consisting essentially in using a pyrotechnical actuating devicee 115 which acts no longer for driving the piston rod towards the forawrd portion of the binding but on the contrary for pulling backwards the piston rod 116 which is pivoted through a ball-and-socket joint 117 onto a lever 118 for locking the rear stop member 119. This rear stop member or grip 119 is pivotally connected about a horizontal transverse shaft 120 onto a yoke-shaped part 121 also pivotally connected about the pin 120 onto a part 122 secured to the ski 50. The part 122 supports the pyrotechnical device 115 as well as a pin 123 for pivotal connection of the locking lever 118. A drawback spring 124 tends to swing the lever 118 about the shaft 123 in the clockwise direction in FIG. 18. The rear stop member on grip 119 extends backwards of a locking lever 125 and is urged to swing back in the counterclockwise direction about the shaft 120 by a biasing spring 126.

Advantageously the lever 118 comprises a shoulder 127 which in the locked position of the binding bears or presses onto the upper edge of the rear stop member or grip 119 for keeping same locked onto the heel of the boot of the ski-runner.

The operation of this alternative embodiment is the following:

When the electrical release system aetuates the device 115, the piston rod 116 is pulled backwards of the binding and carries along in its motion the lever 118 in rotation about the shaft 123 in the counterclockwise direction. The rear stop member or grip 119 is then disengaged from the shoulder 127 and under the action of the drawback spring 126 it swings about the shaft 120 in the counter-clockwise direction for freeing the heel of the boot of the ski-runner. After putting the actuation device 115 again into working order, the rear stop member or grip 119 may be caused to bear upon the heel of the boot of the ski-runner as shown in FIG. 18 while exerting an upward pull upon the end of the lever 125. Under the action of its return spring 124 the lever 118 is then pushed against the rear stop member or grip 119 and when the latter moves down below the level of the shoulder 127 this shoulder is locking same in a position holding the boot against motion.

It should be noted that many proximity sensors or displacement detectors may be used for sensing and measuring the efforts applied to an element of the binding instead of the strain gauges previously described. it is possible indeed to use for instance strain gauges with round wire or pellicular weft or grating, vacuumdeposited strain gauges. semi-conductive strain gauges, strain gauges with stretched wire. capacitive sensors or gauges, inductive proximity displacement gauges or with plunger cores and differential transformer gauges or sensors.

In some cases. the ski-binding which has been described maybe simplified by having a locking brittle element which is broken by the actuation of the pyrotechnical device and then unlocks this ski-binding.

The invention is not at all limited to the forms of embodiment described and shown which have been given by way of example only. In particular it comprises all the technical equivalents of the means described and shown as well as their combinations if the latter are carried out according to its gist and used within the scope of the appended claims.

What is claimed is:

1. An automatically operable safety fastener operated under control of extraneous influences, comprising means for sensing and transducing into an electrical signal at least one force applied to at least one element of the fastener, first comparison means for comparing the electrical signal so derived with a predetermined minimal value, means connected to said first comparison means for integrating with respect to time said transduced signal to provide an integrated signal output only when the magnitude of the transduced signal is larger than said predetermined minimal value, second comparison means for comparing said integrated signal with a predetermined maximum value, and fastener unlocking means actuated only when the magnitude of said integrated signal is greater than the magnitude of said predetermined maximum value.

2. A fastener according to claim 1, wherein said integrated signal is equal to zero when the magnitude of the transduced signal is less than said predetermined minimum value, and wherein said unlocking means comprise a pyrotechnical charge, and means for firing said charge when said integrated signal is higher than said maximum value.

3. A fastener according to claim 2, wherein said charge comprises a blasting cap with detonating material such as explosive powder in which is embedded an electrically conducting winding forming the secondary of a transformer the primary winding of which consists of another electrically conducting winding of said firing means, an electric current being adapted to flow through said primary winding under control of said extraneous influence to fire said charge through induction.

4. A fastener according to claim 3, wherein said winding embedded in said blasting cap with detonating material comprises a spark gap enabling to fire said charge by priming through field effect.

5. A fastener according to claim 3, wherein said winding is closed on itself and enables to tire said charge through heating by Joule effect.

6. A fastener according to claim 1, wherein said unlocking means comprise a circuit including a pyrotechnical charge, a capacitor and means for completing said circuit such as a thyristor enabling said capacitor to discharge into said circuit when said signal integral exceeds said predeten'nined maximum value.

7. A fastener according to claim 1, wherein said unlocking means comprise magnetic or electromagnetic locking circuits and means for saturating or desaturating said circuits when said integral is higher than said predetermined maximum value.

8. A fastener according to claim 1, comprising at least two assemblies each consisting of said sensing and transducing, integrating, first signal comparing and second comparing means, said unlocking means being connected to each assembly actuated when at least one of said integrated signals is higher than the corresponding maximum value.

9. A fastener according to claim 1, wherein said sensing and transducing means provide at least two different signals each corresponding to a force applied to an element of said fastener, said signals being processed by a mixing circuit before being fed to said integrating and first comparing means.

10. A fastener according to claim 1, wherein said sensing and transducing means comprise displacement sensors selected from the group including inductive gauges, capacitive gauges, strain gauges, connected to amplifying means such as operational amplifiers.

11. A fastener according to claim 1, wherein said sensing and transducing means comprise strain gauge sensors mounted in bridge connection and connected to operational amplifiers the output signal of which is transmitted to said integrating and comparing means through an absolute value setting circuit.

12. A fastener according to claim 11, wherein said integrator means comprise an operational amplifier the input of which is connected to the output of said absolute value setting circuit and a capacitor connected in parallel between said input and said output of the operational amplifier.

13. A fastener according to claim 12, wherein said first comparison means comprise a field efiect transistor the drain and the source of which are connected across said integrating capacitor and the trigger gate of which is connected to the output of an operational amplifier the input of which is connected to the output of said absolute value setting circuit and the other input of which is fed with a reference voltage corresponding to said minimum value.

14. A fastener according to claim 11, wherein said second comparison means comprise an operational amplifier the input of which is fed with the output signal from said integrator means and the other input of which is fed with a reference voltage corresponding to said predetermined maximum value whereas the output of which is connected to said unlocking means.

15. A fastener according to claim 1, wherein said integrator means comprise a high pass filter for removing the direct current component of said signal delivered from said transducing means and an operational amplifier including an input resistor and a capacitor connected in parallel across said operational amplifier.

16. A fastener according to claim 1, wherein said second comparison means comprise a first Schmitt trigger circuit with two transistors the interconnected emitters of which are biased to a voltage of predetermined magnitude corresponding to said predetermined maximum value and a relay operating a contact for actuating said unlocking means, said contact closing as soon as said integral exceeds said predetermined maximum value.

17. A fastener according to claim 16, wherein said first comparison means comprise a second Schmitt trigger circuit with two transistors the interconnected emitters of which are biased to a voltage of predetermined magnitude corresponding to said minimum value and a third transistor controlled by said Schmitt trigger circuit and enabling to discharge the capacitor of said integrating means to the ground when said signal is lower than said minimum value and to reset said integrating means.

18. A fastener according to claim 1, forming a safety ski-binding comprising a front stop member movable about a pivot extending at right angles to the plane of said ski and a rear stop member which is mounted for being movable about a transverse pivot extending in parallel relation to said plane of said ski and which is adapted to lock the boot of the ski-runner within said binding. wherein said sensing and transdueing means cooperate with at least one bending strip one end of which, at least in the binding locking position, is made rigidly fast with at least one of said front and rear stop members and the other end of which rests on at least one bearing pointv 19. A fastener according to claim [8, wherein said sensing and transducing means comprise strain gauges adhesively bonded or secured onto at least one side face of said bending strip.

20. A fastener according to claim [8, wherein one of said bending strips is arranged in lengthwise vertical position with respect to said ski while being constantly fast through one end with said front stop member and having its other end guided in a longitudinal slot of a part adjustable in longitudinal position on said ski and which is hearing against a pair of opposite projections integral with the inner walls of said slot.

21. A fastener according to claim 18, wherein said pivot of said rear stop member is secured to a part movable about a transverse pin extending in parallel relation to the plane of said ski. said part comprising at one end a plate adapted to lie underneath the heel of the boot of the ski-runner and at its other end an extension forming one of said bending strips, which extends in longitudinal parallel relation to the plane of said ski whereas its free end is bearing upon a projection integral with said ski.

22. A fastener according to claim 21, wherein said movable part carries said pyrotechnical device actuated by said fastener unlocking means and including a pyrotechnical charge housed in a cylinder also containing a piston the free end of which outside said piston is adapted to act upon means for locking said rear stop member so as to release same and therefore to disen gage the boot of said ski-runner from said ski-binding.

23. A method of automatically unlocking a safety fastener upon the occurrence or under the action of predetermined critical extraneous influences, comprising the steps of sensing and measuring at least one force applied to at least one element of said fastener and comparing said measured force with a predetermined minimum value, wherein the improvement consists in that said method also comprises the steps of integrating said force with respect to time to provide an integrated force greater than zero only when the measured force exceeds said predetermined minimum value. said integrated force being equal to zero for all values of the measures force less than the minimum value. compar ing the magnitude of said integrated force with a predetermined maximum value, and automatically unlocking said fastener when said integrated force, for a measured force higher than said minimum value, becomes higher than said predetermined maximum value.

24. A method according to claim 23, comprising the step of unlocking said fastener by firing a pyrotechnical charge.

25. A method according to claim 23, consisting in unlocking said fastener by magnctical saturation or desaturation of a fastener locking magnetic or electromagnetic circuit.

26. A method according to claim 23, comprising the steps of measuring at least two forces acting upon elements of said fasteners, processing said forces by comparing each one of them with a predetermined minimum value, by integrating and comparing each integral with a predetermined maximum value, and unlocking said fastener when at least one of said integrals becomes higher than the corresponding maximum value for a corresponding force above the corresponding minimum value.

27. A method according to claim 23, comprising the step of measuring at least two forces acting upon elements of said fastener, combining said forces into a resulting force, processing said resulting force by comparing it with a predetermined minimum value, by integrating it, by comparing said integral with a predetermined maximum value and unlocking said fastener when said integral of the resulting force becomes higher than said maximum value for a resulting force above said minimum value, the integral of said resulting force being zero for all values of said resulting force below said predetermined minimum value.

i t t Notice of Adverse Decision in Interference In Interference No. 99,759, involving Patent No. 3,919,563, D. J. Lautier, L. L. Maeder and P. E. Mayer, CONTROLLABLY SELF-RELEASABLE SAFETY FASTENER AND METHOD OF UNLOCKING SAME, final judgment adverse to the petentees was rendered Apr. 10, 1980, as to

claims

7, 9, 11-14, 25 and 27.

[Oflicial Gazette July 92, 1.980.]

Claims

5. A fastener according to claim 3, wherein said winding is closed on itself and enables to fire said charge through heating by Joule effect.

6. A fastener according to claim 1, wherein said unlocking means comprise a circuit including a pyrotechnical charge, a capacitor and means for completing said circuit such as a thyristor enabling said capacitor to discharge into said circuit when said signal integral exceeds said predetermined maximum value.

13. A fastener according to claim 12, wherein said first comparison means comprise a field effect transistor the drain and the source of which are connected across said integrating capacitor and the trigger gate of which is connected to the output of an operational amplifier the input of which is connected to the output of said absolute value setting circuit and the other input of which is fed with a reference voltage corresponding to said minimum value.

18. A fastener according to claim 1, forming a safety ski-binding comprising a front stop member movable about a pivot extending at right angles to the plane of said ski and a rear stop member which is mounted for being movable about a transverse pivot extending in parallel relation to said plane of said ski and which is adapted to lock the boot of the ski-runner within said binding, wherein said sensing and transducing means cooperate with at least one bending strip one end of which, at least in the binding locking position, is made rigidly fast with at least one of said front and rear stop members and the other end of which rests on at least one bearing point.

19. A fastener according to claim 18, wherein said sensing and transducing means comprise strain gauges adhesively bonded or secured onto at least one side face of said bending strip.

20. A fastener according to claim 18, wherein one of said bending strips is arranged in lengthwise vertical position with respect to said ski while being constantly fast through one end with said front stop member and having its other end guided in a longitudinal slot of a part adjustable in longitudinal position on said ski and which is bearing against a pair of opposite projections integral with the inner walls of said slot.

21. A fastener according to claim 18, wherein said pivot of said rear stop member is secured to a part movable about a transverse pin extending in parallel relation to the plane of said ski, said part comprising at one end a plate adapted to lie underneath the heel of the boot of the ski-runner and at its other end an extension forming one of said bending strips, which extends in longitudinal parallel relation to the plane of said ski whereas its free end is bearing upon a prOjection integral with said ski.

22. A fastener according to claim 21, wherein said movable part carries said pyrotechnical device actuated by said fastener unlocking means and including a pyrotechnical charge housed in a cylinder also containing a piston the free end of which outside said piston is adapted to act upon means for locking said rear stop member so as to release same and therefore to disengage the boot of said ski-runner from said ski-binding.

23. A method of automatically unlocking a safety fastener upon the occurrence or under the action of predetermined critical extraneous influences, comprising the steps of sensing and measuring at least one force applied to at least one element of said fastener and comparing said measured force with a predetermined minimum value, wherein the improvement consists in that said method also comprises the steps of integrating said force with respect to time to provide an integrated force greater than zero only when the measured force exceeds said predetermined minimum value, said integrated force being equal to zero for all values of the measures force less than the minimum value, comparing the magnitude of said integrated force with a predetermined maximum value, and automatically unlocking said fastener when said integrated force, for a measured force higher than said minimum value, becomes higher than said predetermined maximum value.

25. A method according to claim 23, consisting in unlocking said fastener by magnetical saturation or desaturation of a fastener locking magnetic or electro-magnetic circuit.