US3406981A - Toe iron for safety ski bindings - Google Patents

Description

Oct. 22, 1968 H. SCHEIB 3,406,981

TOE IRON FOR SAFETY SKI BINDINGS Filed Aug. 10, 1966 3 Sheets-Sheet 1 s 5 2 \\&mA-&m

INVENTOR HERMANN SOHEIB ATTORNEYS Oct. 22, 1968 H. SCHEIB TOE IRON FOR SAFETY SKI BINDINGS 5 Sheets-Sheet 2 Filed Aug. 10, 1966 INVENTOR s m %m E w S m A .2 M R p E. H

Oct. 22, 1968 H. SCHEIB TOE IRON FOR SAFETY SKI BINDINGS 3 Sheets-Sheet 5 Filed Aug. 10, 1966 INVENTOR HERMANN SOHEIB a H v I ,Qam M;

ATTORNEYS 3,406,981 TOE IRON FOR SAFETY SKI BINDINGS Hermann Scheib, Garmisch-Partenkirchen, Germany, as-

signor to Hannes Marker, Garmisch-Partenkirchen, Germany Filed Aug. 10, 1966, Ser. No. 571,534 Claims priority, application Germany, Aug. 28, 1965, M 66,484 7 Claims. (Cl. 280-1135) ABSTRACT OF THE DISCLOSURE A toe iron for safety ski bindings, comprising a pivot pin which is secured to the ski, a pivoted member mounted on said pivot pin and extending at right angles to the ski surface, a spring element controlling the pivotal movement of said pivoted member about said pivot pin, said spring element consisting of a torsional wire spring having crossing free spring arms which are substantially parallel and spaced apart behind the crossing, said pivoted member having a stop which is disposed between the spring arms and engaged by said spring arms under initial stress when the pivoted member is in its central position.

Various toe irons for safety ski bindings are known, in which a pivoted member is mounted on a pivot pin which is secured to the ski and extends at right angles to the ski surface and said pivoted member is pivotally movable about said pivot pin against the action of a spring element, which is designed and arranged so that the foot bears with a forward edge portion of the sole on an abutment surface of the toe iron and is released under the action of a torsional force which is dangerous for the foot, whereas the foot is restored to its central position after small pivotal movements, which are caused by minor lateral jolts.

"In a known safety toe iron of the kind just described, the resistance to the release is generated by a pin which is provided with a collar and under spring pressure and which is accommodated in a horizontal bore of the toe iron and under the pressure of a coil spring is forced against an axial flat of the pivot pin. When the toe iron is deflected from its central position, the collar pin is urged back against the spring pressure by the leading edge of the flat of the pivot pin and its spring pressure tends to restore the collar pin to its initial position so that the restoring torque is applied by the edge of the flat. The effective lever arm which is then available at the pivot pin is les than one half of the diameter of this pin so that a very strong spring is required to ensure an adequate restoring force. Besides, this very strong spring must be horizontally disposed so that the overall length is very large. Furthermore, in this known safety binding the toe iron has a very low stability in its central position because in this position the resistance of the spring to a deflection of the toe iron is very small and progressively increases only as the deflection proceeds. The manufacture of this toe iron is highly expensive owing to the need for a strong coil spring, the large overall length and the high-grade material which must be used for the pivot pin provided with the flat.

In another toe iron of the type under consideration, the means for holding the pivoted member in its central position and for returning this member to said position after a deflection comprises surfaces which are oblique with respect to the axis of the pivot pin and formed on one of the members which are pivotally movable relative to each other, and a pressure element of the other member, which pressure element may also consist of an oblique surface, or of a ball, a roller or the like, and

nited States Patent is urged by axial spring pressure against the first-mentioned surface. This arrangement always involves large frictional surfaces so that the releasing forces cannot be exactly defined. This toe iron is also fairly expensive. Its satisfactory function cannot be ensured because the frictional forces can be reliably overcome only if the oblique surfaces are very steep. With less steep oblique surfaces, such as would be required to enable a restoring within a relatively large range before the foot is released, the toe iron and the gripped boot may be seized in a partly deflected position between the normal position and the release and this seizing of the toe iron and boot may cause a fall of the skier. Such a seizing in a partly deflected position may also occur in the known safety binding described first hereinbefore because the tightener which acts on the heel to produce the forward clamping pressure moves the foot forwardly when the toe iron is being deflected and the restoring force of the spring is not suflicient, owing to the small lever arm described hereinbefore, to reliably overcome the pressure of the tightener and restore the foot to its original position.

It is an object of the invention to overcome the abovedescribed disadvantages in a safety toe iron for ski bindings with means which are as simple as possible. In a toe iron of the type described initially hereinbefore, this object is accomplished in that the spring element consists of a torsional wire spring having crossing free spring arms, which are substantially parallel and spaced apart behind the crossing, each of the members which are pivotally movable relative to each other has a stop, which is disposed between the spring arms and engaged by said spring arms under initial stress when the toe iron is in its central position. When the toe iron is deflected from its normal position, the leading spring arm is deflected by the stop of the pivoted member and the trailing spring arm bears on the stationary stop. Thus, a movement of the toe iron from its normal position will always increase the stress of the torsion spring. The initial stress of the spring is selected so that a movement of the toe iron from its central position is opposed by a sufliciently strong force. Owing to the design of the torsion spring and the utilization of the resiliency of the spring arms, the force is only slightly increased throughout the pivotal movement to the release position. As the torsion spring exerts a direct action, the boot can never be seized between the toe iron and the heel tightener when the boot has been released. The relatively strong spring force of the torsion spring will always return the toe iron and the boot to their central position after harmless lateral jolts. When the foot has been released during a fall, the torsion spring will immediately return the toe iron to its operative position so that no manipulation is required before the skier can step into the binding. The spring arms are only in point contact with the stops on the members which are pivotally movable relative to each other so that the frictional forces are so small that they can be virtually neglected in a consideration of the function of the toe iron according to the invention. There is no deflection of forces and no mechanical advantage so that the release moment is always approximately as large as the restoring torque acting on the toe iron and a seizing of the boot during the releasing operation is prevented. Another important advantage of the toe iron according to the invention resides in that any trouble due to icing is avoided because there are no large surfaces which can be joined by ice, and the torsional spring acting directly in the direction of the pivotal movement would immediately break any resistance due to ice.

In a particularly preferred embodiment of the invention, the toe iron may comprise in a manner known per se a sole holder, which is pivoted to the pivoted member on a pivot pin which is parallel to the pivot pin for the pivoted member, and which sole holder extends over the pivoted member and has at its forward end a depending stop nose, which just as the stop of the pivoted member extends between the spring arms of the torsion spring. In this embodiment, the stop provided on the baseplate serves only for holding the toe iron in is central position and for ensuring a return of the deflected toe iron to this central position. As the two spring arms of the torsion spring are respectively acted upon during the release movement by a stop of the pivoted member and a stop of the sole holder while the pivoted member and the sole holder are performing a shear movement, the stress of the torsion spring and the utilization of said spring is doubled. In this embodiment, a weaker spring may be used than in an embodiment in which one spring arm bears on a stop which is secured to the ski. Thus, the advantage which resides in that a single spring is sufficient for restoring the pivoted member and the sole holder to their central position is supplemented by the further advantage that this spring may even be less expensive than in a toe iron having a single pivot or a separate restoring device for the sole holder.

As has already been mentioned, the increase in force during the outward pivotal movement may be very small. This increase in force depends on the nature of the torsion spring employed, the wire material, the number of convolutions etc. The increase in force is generally only about Owing to this relatively small increase in force, it is not necessary in general to provide for an adjustment of the releasing torque, although such adjustment may be provided for, if desired, by a dislocation of the points where the movable stops engage the spring arms. In a further development of the invention, this may be accomplished in that the torsion spring is mounted on an adjusting member, which is displaceable in the direction of the spring arms relative to the baseplate, which is secured to the ski, which adjusting member can be fixed in position and has a slot for the passage of the pivot pin. The adjusting element may have a resilient detent device for automatically locking the adjusting element in two or more selectable positions relative to the pivot pin or baseplate. This arrangement enables a particularly simple adjustment because it is sufficient to push the adjusting element by hand to the desired position and the adjusting element will automatically be locked in said position. Owing to the described characteristics of the torsion spring, a large number of adjusted positions are by no means required and two adjusted positions will be suflicient if an adjustment is provided for.

In another embodiment of the invention, the pivoted member is mounted on the pivot pin with the aid of a slot so as to be forwardly displaceable. Even with a single-pivot toe iron, this arrangement eliminates the need for a rearward movement of the foot during the outward pivotal movement. Owing to the tightener pressure from the rear, such rearward movement could cause a seizing of the foot so that the release would be prevented. The pivoted member must be guided so that it returns to its initial position also in the longitudinal direction of the ski when the pivoted member is being restored by the torsion spring. For this purpose, the pivoted member may be provided at its forward end with a roller, which bears on a forwardly curved cam wall, which is formed on the baseplate and disposed laterally of the longitudinal center line of the ski.

The tests carried out by the applicant have shown that an optimum value of the initial stress of the torsion spring engaging the stops in the normal position of the toe iron is 30-40 kg. and a torsional wire spring is suitably selected which causes an increase in force by no more than 20% until the release position has been reached.

The Australian patent specification No. 223,091 discloses a safety toe iron in which soleholder wings are mounted on the pivoted member and by the two arms of a torsional wire spring are held in their central position and restored to the same after a deflection. In this toe iron, the resistance of a conventional ball detent device must be overcome by an excessive torque. The torsion spring is under no initial stress or under no substantial initial stress and its free spring arms do not cross. Aboveall, it has not been recognized how torsion springs can be used for controlling the release torque of a safety toe iron, for eflecting a return of the toe iron to its normal position after slight lateral jolts, and for returning the toe iron also after the foot has been released, and what advantages are obtained by such an arrangement.

The invention will be described more fully with reference to the drawings, which show several embodiments by way of example.

In the drawings FIG. 1 is a longitudinal sectional view showing a first embodiment of a toe iron according to the invention,

FIG. 2 is a top plan view showing the embodiment of FIG. 1,

FIG. 3 is sectional view taken on line 33 of FIG. 1 and showing the toe iron in a deflected position,

FIG. 4 is a side elevation, partly in section, showing another embodiment which enables an additional adjust ment,

FIG. 5 a top plan view, partly in section, showing the embodiment of FIG. 4,

FIG. 6 a longitudinal sectional view showing a third embodiment,

FIG. 7 a top plan view showing the embodiment of FIG. 6,

FIG. 8 a sectional view of the embodiment of FIGS. 6 and 7 without sole holder, in a deflected position, taken along line 88 of FIG. 6,

FIG. 9 a longitudinal sectional view showing a fourth embodiment,

FIG. 10 a top plan view showing the embodiment of FIG. 9 in a deflected position, and

FIG. 11 a view of the embodiment of FIGS. 9 and 10 without sole holder, and in a non-deflected position.

The embodiment shown in FIGS. 1-3 is a double-pivot safety toe iron, which is secured to a ski, not shown, by a baseplate 1 and two screws. A pivot pin 2 and a stop 3 are non-detachably secured to the baseplate 1. A pivoted member 4 is pivoted on the pivot pin 2 and carries a threaded stud 5, on which the sole holder 6 is pivoted. By means of the stud 5, the sole holder 6 is vertically adjustable.

The pivot pin 2 is surrounded by a pre-stressed torsional wire spring 7, which has two arms 8 and 9. These arms cross each other and extend parallel to each other in the longitudinal direction of the ski behind the crossing. The arms 8 and 9 embrace the fixed stop 3 and the stop 10 provided on the pivoted member 4 and engage said two stops under an initial stress of 30-40 kg.-cm. During normal skiing, the spring arms 8 and 9 hold the pivoted member 4 in its central position. A compression spring 11 is seated in the pivoted member 4 and acts on a centering pin 12, which tends to hold the sole holder 6 in its central position. To ensure an automatic return of the sole holder 6 to its central position after any deflection, the sole holder is provided with a recess 13, which is shaped so that a deflection of the sole holder causes the centering pin 12 to be progressively depressed against the action of the spring 11. It will be understood that different means may be employed to hold the sole holder in its central position and a torsion spring may also be used for this purpose. Essential for the invention is only the torsional wire spring 7, which holds the pivoted member in its central position and determines the releasing torque. The threaded stud 5 is mounted in two ears 14 and 15 of the pivoted member 4. A retaining collar 17 is provided on the pivot pin 2 for a captive connection of the toe iron to the ski.

A lateral force causes a deflection of the sole holder 6 and the pivoted member 4. FIG. 3 shows the load on the torsion spring 7 after a deflection of the toe iron. When the stop of the pivoted member 4 turns the spring arm 9 so that the convolutions of the torsion spring 7 are contracted and the stress of the spring is increased, the other arm of the spring bears on the stop 3. When the pivoted member 4 is pivotally moved in the opposite direction, the functions of the spring arms 8 and 9 will be interchanged too. Lateral jolts which are harmless for the leg are taken up in this manner, and the toe iron returns to its central position when the jolt has been terminated. If the lateral jolt or the torsional stress on the leg exceeds the release torque determined by the torsional wire spring 7, the sole holder 6 and the pivoted member 4 yield to such an extent that the boot is released. After the fall, the toe iron returns automatically to its central position and is immediately ready for use again.

In the embodiment shown in FIGS. 4 and 5, the releasing torque of the trosion spring 7 is adjustable. The structure and design of the toe iron are the same as in the embodiment of FIGS. 1 to 3. The embodiment now to be described comprises additionally the adjusting plate 20, which receives the torsion spring 7. A displacement of the torsion spring 7 by the adjusting plate changes the releasing torque because the point of engagement between the stop 10 and the spring arms 8 and 9 is changed, as is shown in FIG. 5. The torsion spring 7 is held on the adjusting plate 20 between the stops 3 and 21 which are integral with plate 20. The adjusting plate 20 is provided with two guide slots 22 and 23 of limited length, which are respectively engaged by a retaining pin 24 and by a set screw 25, which enables any desired adjustment. Plate 20 also defines a slot 46 which slidably engages pivot pins 2 to allow longitudinal movement of plate 20 with respect to base plate 1 and pin 2.

A particularly preferred embodiment is shown in FIGS. 6 to 8. This embodiment comprises only a single torsion spring 7 for restoring the pivoted member 4 and the sole holder 6 to their central position. The sole holder 6 has no teeth for engaging the sole but a wide mouth, which embraces a wide portion of the forward edge of the sole of the boot so that the stepping into the binding is facilitated. The baseplate 1 is provided with a cylindrical extension 19, which threadedly receives the pivot pin 2. This extension 19 is surrounded by the pre-stressed torsion spring 7. The two arms 8 and 9 of this spring embrace the stop 3, which is secured to the ski, the stop 10 of the pivoted member 4 and the stop 16 of the sole holder 6. In this case the stop 3, which is secured to the ski, serves only for centering the toe iron in its central position. In this embodiment, any lateral load results immediately in a shear movement. The stop 16 on the sole holder 6 stresses the spring arm 9 and the stop 10 of the pivoted member 4 stresses the spring arm 8 in the opposite direction. A reversal of the lateral force results in a reversal of the directions of the action of the stops 10 and 16.

FIG. 8 shows the loading of the springs after a deflection. The widely embracing sole holder 26 enables a sudden release of the boot. 'Just :as the embodiments described hereinbefore with reference to FIGS. 1 to 5, this embodiment provides for an elastic range before the release. The use of a single torsion spring for restoring the pivoted member 4 and the sole holder 6 in a double-pivot binding enables a simple and inexpensive manufacture. FIGS. 9 to 11 show an embodiment of a single-pivot toe iron according to the invention. In this case, the pivoted member 4 is pivotally movable and displaceable in the longitudinal direction. The baseplate 1 is provided with a pivot pin 2 and a cam wall 27 for a pressure roller 28, which is mounted on the pivoted member 4. The pressure roller 28 is rotatably mounted on the pin 29. The lower end of the pin 29 serves as a stop 10. In this embodiment the sole holder 30 is secured to the pivoted member 4 in known manner by a screw 31. The torsion spring 7 is seated in the spring retainer 32, which is slidably mounted on the pivot pin 2. The spring retainer 32 comprises depending guide pins 33 and 34, which extend into longitudinal slots 35 and 36 in the baseplate 1. The pin 34 serves also as a stop for the arms 8 and 9 of the torsion spring. The collar screw 37 in the upper end of pin 2 slidably secures the pivoted member 4 and the spring retainer 32 to the base plate 1. A slot 38 in the member 4 slidably engages pin 2. In order to prevent member 4 and sole holder 30 from exerting an increasing force against the heel tightener as they rotate about pin 2 during torsional deflection, member 4 can move forward on pivot 2 because of the cooperation of cam 27, roller 28 and slot 38, as best seen in FIGURE 10. The cam wall 27 engaged by the pressure roller 28 extends on both sides of the longitudinal center line of the ski and presents a convex surface to roller 28.

In this embodiment, the releasing torque is adjustable in two steps. The torsion spring 7 is mounted in the spring retainer 32 which is adjustable longitudinally in two positions. Lateral depressions 39 and 40 are provided in the spring retainer 32 to facilitate its manipulation. A leaf spring 41 secured in a recess in spring retainer 32 bears on the pivot pin 2 and locks the spring retainer in position. There are only two locking positions. The leaf spring 41 has a central elevation 43, which lies before the pivot pin 2 in one locking position and behind the pivot pin 2 in the other locking position. The spring retainer 32 has a slot 42 which slidably engages pivot pin 2. The releasing torque is changed by moving members 4 and 32 so that detent 43 is forward or to the rear of pin 2. This changes the point at which stop 10 contacts arms 8 and 9 of spring 7 and thus changes the force required to deflect them. In this embodiment there is also a shock-absorbing action until the binding is released because a directly acting torsion spring tends to restore the pivoted member together with the sole holder and the boot to their central position unless the lateral or torsional force is so strong that the angle at which the boot is released is exceeded.

What is claimed is:

1. A toe iron for safety ski bindings, comprising a pivot pin which is secured to the ski, a pivoted member mounted on said pivot pin and extending at right angles to the ski surface, a spring element controlling the pivotal movement of said pivoted member about said pivot pin, said spring element consisting of a torsional wire spring having crossing free spring arms which are substantially parallel and spaced apart behind the crossing, said pivoted member having a stop which is disposed between the spring arms and engaged by said spring arms under initial stress when the pivoted member is in its central position.

2. A toe iron according to claim 1, further comprising a sole holder, a second pivot pin pivotally mounting said sole holder on the pivoted member about an axis which is parallel to the pivot pin for the pivoted member, said sole holder extending over the pivoted member and having at its forward end a depending stop nose also extending between the spring arms of the torsion spring.

3. A toe iron according to claim 1, further including an adjusting member upon which the torsion spring is mounted, said adjusting member being displacea-bly mounted on the ski in the direction of the spring arms and having a slot for the passage of the pivot pin.

4. A toe iron according to claim 3, characterized in that the adjusting element has a resilient detent device for automatically locking the adjusting element in one of a plurality of selectable positions relative to the pivot pin.

5. A toe iron according to claim 1, characterized in that the pivoted member is mounted on the pivot pin with the aid of a slot so as to be forwardly displaceable.

6. A toe iron according to claim 5, characterized in that the pivoted member is provided at its forward end with a roller, which bears on a forwardly curved cam wall, which is formed on the baseplate and disposed laterally of the longitudinal centerline of the ski.

7. A toe iron according to claim 1, characterized in that the spring has an initial stress of 30-40 kg. and its 7 8 force is increased by about 20% until the release position FOREIGN PATENTS is reached. 2 43 3 196 References Cited 1 2 France' UNITED STATES PATENTS BENJAMIN HERSH, Primal Examiner.

3,105,696 10/1963 Rehacek 2801l.35 5 L. D. MORRIS, JR., Assistant Examiner.

3,329,438 7/1967 Lusser 280-11.35

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