US3192767A - Torque measuring device for determining the safety of ski foot fastenings - Google Patents

Description

y 6, 1955 J. o. OUTWATER 3,192,767

TORQUE MEASURING DEVICE FOR DETERMINING" THE SAFETY OF SKI FOOT FASTENINGS' Filed April 30. 1963 INVENT OR. JOHN O. OUTWATER FIG.3

United States Patent O 3,192,767 T GRQUE WEASURKNG DEVICE FOR DETERMIN- ENG THE SAFETY OF SKI FOOT FASTENINGS John 0. ()utwater, 62 Overlake Park, Burlington, Vt. Filed Apr. 30, 1963, Ser. No. 276,822 1 Claim. (Cl. 73-439) This invention relates to a force measuring device for ski boot bindings and, more particularly, to a device for measuring the torque required to cause a boot binding to release.

In attaching a skiers boot onto a ski, it is common practice to utilize a so-called safety binding which releases the toe of the boot from the ski when suflicient force, such as the force caused by accidental turning of a ski, is exerted upon the binding. Safety bindings are usually adjustable so that they may be caused to release upon application of a predetermined amount of force. It is desirable that they be set so that they will not release under the strains encountered during normal skiing, but so that they will release under abnormally high strains so as to avoid snapping of the skiers leg in case of an accident.

Analysis of the large number of legs broken annually during skiing reveals that most of them result from excessive torsional or twisting forces when the bindings failed to release before the legs snapped. However, some accidents are caused by a binding adjusted so that it will release too easily, thereby releasing a ski under non-dangerous strain of normal usage. The skier is thus caught between the Scylla and Charybdis, so to speak, of a binding that may be set to release with the application of either too much or too little force. Up until now, there has been no way, other than by guess, for determining whether the binding has been set so that, on the one hand, it will break his leg before it releases or, on the other hand, a ski will come off during the otherwise perfect execution of a slalom. The object of this invention is to provide a device for testing and indicating the torque required to release a ski boot binding so that the binding may be set to hold a ski boot within known safe limits of tenacity.

These and other objects will be apparent from the following specification and drawings, in which:

FIG. 1 is a perspective view showing the invention in typical position of use;

FIG. 2 is a plan view of the device; and

FIG. 3 is a side elevation of the device.

Referring now to the drawing, in which like reference numerals denote similar elements, there is shown a typical ski 2 on which a ski boot 4 is held at the rear by a heel plate 6 and, at the toe 8, by a binding 10. The details of binding 10 form no part on this invention, and it may be any one of various safety types, the essential characteristics being that the binding will release the toe of the boot if suflicient torque is applied between the boot and the ski. In most such bindings, the tenacity is adjustable.

The torque measuring device 12 with which the invention is concerned operates upon the general principles of torque wrenches, of which those shown in U.S. Patents 1,775,076; 2,256,478; and 2,803,133 are exemplary, this invention consisting in the recognition of the problem and the new combination of structural elements to solve it. Device 12 consists of an arm, hereinafter called a dummy last 14 which engages within a ski boot; a post 16 rigidly affixed to the dummy last; and a torque bar 18 3,192,767 Patented July-6, 1965 aflixed at or near its middle to the top of the post so as to provide two oppositely extending arms 20 and 22; a pointer 24 having one end attached to the torque bar at 26, preferably at or adjacent the middle of the bar; and a scale 28 afixed on one of the arms beneath the free end 30 of the pointer.

Dummy last 14 and post 16 are preferably made of metal, of suificient strength and rigidity to resist bending or substantial deformation under the forces required for testing the holding strength of the boot binding. Dummy last 14 need not be of any particular configuration so long as it fits freely into ski boots of various size, and is of sufficient length so that its front end will engage against one inner side of the boot near the toe of the boot, and its rear end will engage against the opposite inner side of the boot near the heel. Post 16 should be long enough so that torque bar 18 will be disposed freely above the top of the boot. Torque bar 18, also preferably of metal, is a square bar, and may be provided with hand grips 30 at its ends. The necessary deflection characteristics of torque bars of this type are well known in the torque wrench art, it being apparent that when dummy last 14 is inserted into an anchored boot 4 and the free ends of bar arms 20 and 22 are twisted clockwise or counterclockwise, bar arms 20 and 22 will deflect equally and oppositely. If pointer 24 be anchored, as at 26, at or adjacent the middle of bar 18, scale 28 will be shifted laterally with the deflection of bar arm 22 to which it is attached so that the free end 30 of the pointer will overlie a scale reading away from the center of the scale. Scale 28 may be calibrated in terms of foot pounds, or in terms of lashing secure, danger for girls, danger for men, etc. While, obviously, the

torque required to break human legs will vary in accord-.

ance with the size and bone characteristics of individuals, reliable statistics developed by testing on fresh specimens can be used to establish safe averages for various categories of skiers. Whatever be the calibration of the scale, the binding should test so that it will not free the toe of the boot by applying less torque to bar 20 than that encountered during normal skiing, and yet so that it will release the boot Well below the torque required to snap a leg bone. In accordance with usual test procedures, the statistical or theoretical values ascribed for the upper and lower extremes of the safe torque range are subject to empirical modification as more experience with the device is gained.

If it is desired to amplify the swing of scale 28 relative the free end 36 of pointer 24, the pointer may be lengthened and anchored on arm 20 at a desired point further out towards the free end of arm 20 so that the opposite deflections of arms 20 and 22 will deflect both pointer 24 and scale 28.

The invention is not limited to the details illustrated and described herein, but is intended to cover all substitutions, modifications and equivalents within the scope of the following claim.

I claim:

A device for measuring the .tenacity of self-releasing means which holds a ski boot on a ski, comprising a dummy last consisting of a substantially L-shape member having a foot portion and a stem portion integrally connected to one another, the length of said foot portion being considerably longer than the width thereof, said foot portion being adapted to engage lengthwise within the foot of the boot, the free end of the foot portion engaging in the toe portion of the boot on one side of the boot, the juncture of the foot and stem portion engaging in the heel portion of the boot on the opposite side of the boot, and the stern portion extending outwardly through the ankle of the boot, a torque bar non-rotatively affixed intermediate its ends to the top of stem portion and providing two arms extending outwardly in opposite directions from the stem portion, whereby to apply torque to the boot via said L-shape member tending to cause said self-releasing means to free .the boot from the ski, and means for measuring the deflection of at least one arm relative to the stem portion upon application of said torque.

References Cited by the Examiner UNITED STATES PATENTS 2,698,757 1/55 Berlenbach 28011.35

OTHER REFERENCES Torque Manual, 2nd edition, 1957, P. A. Sturtevant Co., Addison, Ill., 27 pages. Pages 8, 10 and 13 relied on.

10 RICHARD C. QUEISSER, Primary Examiner.

ROBERT L. EVANS, Examiner.

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