US3432180A - Heel engaging unit for a safety ski binding - Google Patents

Description

March 11, i969 w, SUHNER 3,432,180

HEEL ENGAGING UNIT FOR A SAFETY SKI BINDING Original Filed Nov. 8, 1966 Sheet of 5 INVENTOR. bg {t} fuer' W. SUHNER HEEL ENGAGING UNIT FOR A SAFETY SKI BINDING Sheet Original Filed Nov. 8, 1966 INVENTOR.

(u A u W. SUHNER March ll, 1969 3,432,180 HEEL ENGAGING UNIT FOR A SAFETY. sx1 BINDING Sheet Original Filed Nov. 8, 1966 INVENTOR. 4/,2 r 7 fu er March 11, 1969 w. SUHNER 3,432,180 HEEL ENGAGING UNIT FOR `A SAFETY SKI BINDING Original Filed Nov. 8, 1966 Sheet 4 of INVENTOR.

March 11, 1969 w. SUHNER 3,432,180

HEEL ENGAGING UNIT FOR A SAFETY sx1 BINDING Original Filed Nov. 8, 1966 Sheet 5 of 5 United States Patent Office Claims priority, application Switzerland, Nov. 11, 1965, 15,587/ 65 U.S. Cl. 28011.3S 31 Claims Int. Cl. A63c 9/00 ABSTRACT OF THE DISCLOSURE The present invention relates to a heel engaging unit for a safety ski binding, and more specifically to a strapless heel engaging unit provided with heel engaging means which automatically secure the heel of a ski boot to the unit Iwhen the user steps with the heel into the heel engaging means while the latter are in a step-in position and which subsequently holds the ski engaging means in a downhill run position in which the bottom surface of the heel will be maintained closely adjacent to the top surface of the ski or in a walking or cross-country skiing position in which the heel of the ski boot may move within Certin limits upwardly and downwardly with respect to the top surface of the ski.

This is a continuation of application Ser. No. 592,866, filed Nov. 8, 1966.

Heel engaging units for safety ski bindings are known in the art in which the heel engaging unit cooperates with a front engaging unit for automatically securing the heel engaging unit to the heel of a ski boot when the user steps with the ski boot into the binding, however these known safety ski bindings have the disadvantage that they are adapted only for use during downhill run since in these bindings the heel of the ski boot cannot be lifted from the top surface of the ski.

Other strapless Iski bindings are known in the art which are suitable for downhill run as well as for cross-country skiing, These ski bindings are usually provided for crosscountry skiing with additional members, for instance a plate extending beneath the sole of the ski boot. Such plates are liable to twist or break, and in addition these ski bindings use for cross-country skiing mechanical linkage systems which have to be closed by means yof a tightening member. The changeover of these known ski bindings for downhill run use or for cross-country skiing use is usually diicult and time-consuming, and these known ski bindings are also very often dependent on a specific shape of the heel of the ski boot for their proper function. ln addition these known ski bindings have usually a poorly functioning release mechanism for releasing the heel engaging means from the heel of a `ski boot during a fall of the skier to thus prevent injury to the skier during such fall.

It is an object of the present invention to provide a heel engaging unit for a safety lski binding which avoids the above-mentioned disadvantages of such units known in the art.

It is a further object of the present invention to provide a heel engaging unit for a safety ski binding suitable for downhill run use as well as for cross-country skiing which not only permits a faultless and quick engagement and disengagement with the heel of a ski boot, but which will also permit, even during skiing, a quick change-over from one to the other use.

It is also an object of the present invention to provide a heel engaging unit for a safety ski binding of the aforementioned kind which not only permits a perfect guiding of the ski during cross-country skiing, but which also per- Patented Mar. 11, 1969 mits to limit the up-and-down movement of the heel of the ski -boot relative to the ski during cross-country skiing so that the user will tire less than with other ski bindings known in the art.

It is an additional object of the present invention to provide a heel engaging unit for a safety ski binding with exactly adjustable means for instantaneously releasing the heel engaging means of the unit from the heel of the ski boot during excessive upward pressure on the heel engaging means, as will occur during a forward fall of the skier.

The heel engaging unit according to the present invention is strapless and does not require any connecting elements which protrude laterally to` opposite sides of the ski boot or which are arranged beneath the sole of the ski boot. It is further adapted for use with most of the ski boots presently available without requiring any additional elements or metal fittings mounted on the ski boot. The heel engaging Iunit is also usable in combination with Various front units or front jaws presently available on the market. The pressure at which the front portion of a ski boot is pressed against the front jaws by the heel engaging unit of the present invention is steplessly adjustable and so is the releasing moment for releasing the heel engaging means of the heel engaging Iunit from the heel of a ski boot during forward fall. of the skier. The aforementioned pressures are readable on the heel engaging unit after the skier has stepped into the safety ski binding and the means for indicating the pressure will not indicate the adjusted pressure but the actually acting pressure.

With the above objects in View, the heel engaging unit according to the present invention adapted to cooperate with a front unit of a safety ski binding for pressing the front portion of a ski boot into said front unit of the ski binding mainly comprises support means adapted to be mounted on a ski rearwardly of the front unit thereon, heel engaging means constructed and arranged to automatically egage the heel of a ski boot when the user steps with the heel onto the heel engaging means, and linkage means connecting the heel engaging means to the support means and guiding the heel engaging means movable relative to the ski along a predetermined portion of a substantially circular path having its turning axis in the region of the top surface of the ski and adjacent the front unit of the ski binding so that during the use of the ski binding for walking the heel engaging means remain substantially non-shiftably connected to the heel of the ski boot.

The linkage means preferably comprise a first parallelogram guide including an elongated member having a front portion and a rear portion and a pair of first link means respectively pivotally connected at opposite end-s thereof to said support means and the elongated member in the region of the rear portion of the latter, and a second parallelogram guide including a pair of second link means one of which is pivotally connected at one end thereof to one of the first link means and at the other end thereof to the heel engaging means and the other of which is pivotally connected at one end thereof to the elongated member in the region of the front portion of the latter and at the other end thereof to the heel engaging means.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following `description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a longitudinal section taken along the line I-I of FIG. 5 of a heel engaging unit according to the present invention and `showing this unit in the uppermost position during use of the unit for walking or cross country skiing;

FIG. 2 is a partially cross sectioned side View of the unit illustrated in FIG. l and showing the unit in a stepin position ready to receive the heel of a ski boot;

FIG. 3 is a sectional view similar to FIG. l and showing the unit in downhill run position;

FIG. 4 is a partially sectioned side view of the unit and showing the unit adjusted for walking on steep slopes whereby the position shown in full lines is the lowest and the position shown in dash-dotted lines the highest of the thus adjusted positions;

FIG. 5 is a top View of the unit shown in the position as in FIG. 3;

FIGS. 68 illustrate certain components of the unit respectively in side view, front view and section; and

FIGS. 9-12 illustrate some alternatives of parts of the unit.

Referring now to the drawings and more specically to FIG. 1 of the same, it will be seen that the heel engaging unit according to the present invention for a strapless safety ski binding mainly comprises support means which include a base plate 1 adapted to be connected by screws or the like to the top surface of a ski 2, as indicated in FIG. 3, and a frame 3 mounted on the base plate 1 movable in longitudinal direction of the ski. The frame 3 includes a pair of guide rails 5 which respectively encompass lateral edge portions of the base plate 1 to guide the frame in longitudinal direction of the base plate, and a pair of lateral walls 7 projecting upwardly from the guide rails 5 and being connected at the front end the rear end thereof by a pair of transverse bolts 11 and 13, respectively. The bolts 11 and 13 are formed with bores therethrough aligned along a common axis normal to the axis of the bolts and a rod 15 extends through the aforementioned bores preferably fixed to the bolts 11 and 13 in any convenient manner. A cylindrical member 17 provided on the outer surface thereof with a screw thread engaging in corresponding threads 27 on the Ibase plate 1 is mounted on the rod 15 coaxially therewith and tunably and axially movable with respect thereto. A pair of coil compression springs 19 and 21 are arranged to the left side, as viewed in FIG. l, of the member 17 about the rod 15. An indicator member 23 is slidably arranged on the rod 15 between the left end face, as viewed in FIG. 1, of the member 17 and the right end of the spring 21, and the indicating member 23 extends with at least one lateral portion through a cutout 9 in at least one of the side walls 7 of the frame 3. The indicating member 23 cooperates with marks 25 provided on the guide rails 5. An abutment member 29 is located between opposed ends of the springs 19 and 21 and guided on the rod 15 by means of a sleeve 30 fixedly connected to or integral with the member 29.

The heel engaging unit comprises further heel engaging means including the members 92, 107 and 134 constructed and arranged, as will be described later on in detail, to automatically engage the heel of a ski boot when the user of the ski steps with the bottom face of the heel onto a forwardly projecting engaging portion 110 on the member 107.

The heel engaging unit includes further linkage means connecting the heel engaging means to the frame 3 of the support means for guiding the heel engaging -means relative to the ski along a predetermined portion of a substantially circular path having its turning axis in the region of the top surface of the ski and adjacent to a front unit provided thereon so that during use of the ski binding for walking the heel engaging means remains substantially non-shiftably connected to the heel of the ski boot.

The linkage means comprise a rst parallelogram guide including a pair of rst link means or link arms 35 and 37. The longer arm 3S is pivotally connected at its bottom end to a bearing bolt 31 extending between a front portion of the side walls 7, whereas the lower end of the shorter arm 37 is pivotally connected to a bearing bolt 33 extending between a rear portion of the aforementioned side walls. The first parallelogram guide includes furthe-r an elongated member 39 which is preferably cap-shaped and a pair of upper bearing bolts 43 and 45 extend between and are connected to side walls of the cap-shaped member 39 and the upper ends of the link arms 35 and 37 are respectively pivotally connected to the bearing bolts 43 and 45. A rubber buffer is preferably connected to the rear end of the cap-shaped member 39.

The longer link arm 35 includes an upper and a lower bearing bushing 47, 51 respectively mounted on the bearing bolts 43 and 31 and connected to each other by parallel walls 49 extending spaced from each other and substantially normal to the axes of the bushing 47 and S1, as best shown in FIG. 6. The upper bushing 47 is provided substantially midway between opposite ends thereof with an annular groove 53, for a purpose as will be described later on. A cam 55 projects from the lower bushing 51, which cam has a stepped portion 56 and which defines together with the ca-m a cam face 58.

The heel engaging unit includes further a second parallelogram guide including two pairs of link members 84 and 130. The upper shorter link members 84 are pivotally mounted at the rear ends thereof on a pivot pin 41, whereas the lower longer link members 130 are pivotally mounted at the rear ends thereof by means of a pivot pin 132 on the link member 37 between the ends of the latter. The front ends of the link members 84 and 130 are pivotally connected to the heel engaging means for movably carrying the same. As best shown in FIG. 8 each of the link members 84 is formed adjacent one end thereof with an opening 89 through which the pivot pin 41 extends, whereas in the region of the opposite end thereof a short cylindrical member or shaft 86 is turnably mounted. The short shafts `86 of the link members 84 respectively extend through bores in upper portions 94 of the member 92 so that the latter may turn about the axes 104 of the two short shafts 86. The member 92 has a front wall 96 which is provided at its front surface thereof with a plurality of teeth 98 and which if formed substantially midway with a longitudinal slot 100. The member 92 is further formed in the side walls thereof with mouth-shaped guide slots 102.

A first heel engaging member 134 is adjustably connected to the member 92 and for this purpose the heel engaging member 134 is provided at its rear face teeth 136 corresponding to the teeth 98 and interengaged with the latter. The heel engaging member 134 is connected by means of a screw 144 extending through the slot 100 and a nut 145 to the member 92. Preferably the nut 145 has projections extending into the slot 100 to prevent turning of the nut during tightening of the screw 144. The heel engaging member 134 has at its upper end a forwardly projecting heel engaging portion 142 adapted to engage the upper surface of a rim portion of a heel 4 of a ski boot as indicated in FIG. 3. The heel engaging portion 142 has an upper downwardly inclined guide surface 140 and this member has also a front guide surface 147 adapted to guide the heel of a ski boot onto a forwardly projecting portion of the second heel engaging member 1'07.

The second heel engaging member 107 has a bottom wall, the front portion 110 of which forms a second heel engaging portion adapted to engage the bottom surface of the heel of a ski boot, as shown in FIG. 3, and a pair of side walls 112, each provided with a pair of bores 114 and 116 as best shown in FIG. 7. The side walls 112 are extended at the upper end thereof into rearwardly projecting noses 118 each having an upper guide surface 120 and a bottom edge 122 adapted to engage onto the bolts 41. A bolt 124 extends through the bores 116 in the `side walls of the member 107, and the bolt 124 extends also through bores 88 in the short shafts 86 carried by the link members 84, which bores 88 are eccentrically arranged with regard to the axis 104 s of the shafts 86. The bottom wall of the member 107 has a rearwardly projecting locking portion 126. A pin 128 extending through the bores 114 in the side walls of the member y1017 pivotally connects the latter to the front ends of the link members 130.

Since ski shoes are manufactured which have so-called walking heels, in which the rear end of the sole is rounded and would therefore not properly engage the portion 110 of the member 107, a bore 110', as shown in FIG. 7 may be provided in which a projecting pin or the like, not shown in the drawings, may be secured.

A lever 60 is pivotally mounted at the front end thereof by means of the bolt 41 on the cap-shaped member 39. The side walls of the lever 60 carry in the region of the front end thereof a pair of rollers 74, as best shown in FIGS. 1 and 5, which are adapted to engage the upper faces 120 of the noses 118 on the member 107. The lever 60 carries further a roller 76 turnably mounted thereon by a pin 78. Spring means in form of a coil spring 71 are operatively con-nected to the lever 60 tending when stressed to turn the latter depending on the position of the lever in counterclockwise or clockwise direction about the pivot pin 41. The coil spring 71 is guided by means of guides 66, 68 respectively connected at the upper ends thereof by short stud pins 62, 64, only one of which is actually illustrated in the drawings, to side walls of the lever 60. Sandwiched between these guide members 66 and 68 is an additional guide member 70 which is connected by means of a fork 72 located in the groove 53 of the bushing 47 to the link member 35. The lever 60 has further two downwardly projecting noses 80, a rearwardly extending handle portion 82 and further between the noses 80 and the roller 76 and further two outwardly extending abutment portions 81.

The above-described heel engaging unit will operate as follows:

In FIG. 2 the unit is illustrated in a step-in position ready to receive a heel of a ski boot. In this position the cap-shaped member 39 is in its lowest position just above the two guide rails 5 and covers the adjusting screw 17 and the coil springs 19 and 21. Only the indicator slide 23 projects with later-al portions thereof through the cutouts 9 of the side walls 7. The lever 60 is in slightly lifted position in which the roller 76 carried thereby abuts against the portion 56 of the cam 55 as well as against the rearwardly projecting locking portion 126 of the member 107. The two rollers 74 are located beneath the noses 118 of the member 107 so that the latter is freely turnable about the bolt 128.

The member 92, which is turnable about the short shafts 86 of the links 84, is through the guide slots 102 and the bolt 128 in operative connection with the member 107. The locking portion 126 of the member 107 engages 4the roller 76 in this position at a point which is above the Iturning axis of the roller 76. In this position of the unit the heel 4 of a ski boot is pushed against the heel engaging portion 1110 of the member 107 by moving the heel along the guide faces 147 of the member 134 and if the heel i-s then pressed downwardly onto the portion 110, the members 107 and the links 84 will be turned about the bearing bolt 41 while the guide slots 102 move along the pin 128 downwardly and rearwardly. At the same time the whole movable upper part of the unit is pushed rearwardly whereby the bearing bolts 31, respectively 33 `senve at fixed points, whereas the link members 132 swing downwardly and rearwardly. During this movementof the members 107 and 92 the short shafts 86 are also turned so that the bolts 124 will move from the position `shown in FIG. 2 to the position shown in FIG. 3, whereby the spacing between the members 134 and 107 respectively bet'ween the heel engaging portions 142 and `110 of these members will be changed corresponding to the eccentricity of the axes of the bolts 124 and the short shafts 86.

In this way a proper securing of the heel between the members 107 and 134, which in the step-in position as shown in FIG. 2 are spread apart to facilitate easy insertion of the heel, is assured. The link members 84 will turn about the bearing bolt 41 until the heel engaging portion 142 of the member 134 will engage the upper rim surface of the heel. lIf the heel is now further pressed downwardly, then the movable parts of the unit are pushed rearwardly since the shoe engages with a front portion thereof a front unit of the ski binding, no-t shown in the drawing, Thereby the two springs 19 and 21 are compressed. This pressure acts in longitudinal direction of the shoe sole and will obtain a predetermined value depending on the adjustment of the adjusting screw 17. The thus obtained pressure is readable on the lateral marks 25.

During lifting of the ski boot the member 92 has the tendency to turn about the axis of the short shaft 86 whereby the lower part of the member 134 is pressed against the heel 4 while the upper part tends to move away from the latter. This ltendency is partly counteracted by the pressure exerted by the springs 19 and 21. This tendency can be completely eliminated by the following provisions:

(a) The member 92 is guided on the member 107 in such a manner that these members are movable relative to each other in direction of a line connecting the centers of the bores 114 and 116 in the member -107 or slightly inclined to this line and so that the member 92 may also turn about the axis of the shafts 86 within narrow limits. This guiding is obtained by means of the guide slots 102 which are cooperating with the bolt 128 xed to the member 107. lThe thus obtained limited turning movement assures that the ski boo-t in the downhill run position shown in FIG. 3 is not pressed too hard against the top surface of the ski.

(b) Another possible solution consists in providing the member 92 with two noses 92 similar to the noses on the member 107, which extend over the bearing bolt 41 and which during lifting of the heel 4 abut against this bolt. The shoe releasing effect occurs in this case only shortly before displacement of the roller 76. The force acting thereby on this roller is, due to the lever action produced by the turnable mounting of the member 107 between the member 134 and the mentioned abutment on the bearing bolt 41, greater than th-e force produced during lifting of the heel (FIG. l2).

During movement of the various engaging unit from the position as shown in FIG. 2 to the position as shown in FIG. 3, the locking portion 126 will glide downwardly along the surface of the roller 76 and when the locking portion 126 passes downwardly beyond the critical point (FIG. 3), the lever 60 tends under the influence of the spring 71 to turn in clockwise direction so that the roller 76 is moved on the cam surface 58 of the cam portion 55 against the point of the cam portion to thereby exert on the members 92, 107 and 134 a closing moment and to hold these members in locked position. Since the locking portion 126 slides on the turnable roller 76, the wear on these two components will be very small.

During downward movement of the heel 4 the springs 19 and 21 will be compressed, since the front portion of the ski boot is held by a front unit of the ski binding, not shown in the drawing. The forward pressure produced by the springs 19 and 22 will depend on the adjustment of the screw member 17 on the base plate 1 and the forward pressure exerted by the springs is indicated by the indicator slide 23 and the marks 25. The compression of the spring 19 can, due to the length of the sleeve 30, not `surpass a predetermined magnitude. The adjusting screw 17 may be adjusted in such a manner that when a desired compression of the springs 19 and 21 is obtained in the downhill run position, the lever 60 abuts against the cap-shaped member 39 and prevents: that the roller 76 is moved further forwardly along the locking portion elements of the heel 7 126 so that the whole system would be locked and could be opened only -by turning the lever 60 by means of extraneous forces in counterclockwise direction, that is, the heel engaging members would not open during a forward fall of the skier, and the ski binding would not act as safety ski binding any longer.

In the downhill run position, as shown in FIG. 3, the roller 76 is moved forwardly by the lever 60 until the two noses 80 on the side walls of the lever abut with front faces thereof against the abutment member 29 which is arranged axially movable between the opposed ends of the springs 19 and 21.

The compression of the springs 19 and 21 determines therefore the position of the member 29 and therewith the position of the roller 76 with regard to the locking portion 126. The greater the compression of the springs 19 and 21 is, the further will the roller 76 move over the lock-ing portion 126 and the greater will be the necessary force to open the binding during overloads, that is, during a forward fall of the skier. The release moment is therefore dependent on the adjustment of the adjusting screw 17 and the thus produced compression of the springs 19 and 21. This simplifies proper adjustment of the safety ski binding.

To adjust the moment at which the binding opens during a forward fall of the user it is also possible to provide the following means:

The maximum forward movement of the roller 76 over the locking portion 126 may be adjusted by providing an adjusting screw 153 as shown in dash-dotted lines in FIG. 3 which abuts with its upper end against the bottom surface of the handle portion of the lever 60 to prevent thereby further turning of the lever in clockwise direction and resulting forward movement of the roller 76.

Furthermore, the elements cooperating with the spring 71 may be designed in such a manner that the closure pressure acting on the roller 76 and produced by the spring 71 is provided with a characteristic which is desirable for the opening of the binding during a fall of the skier.

When during a fall of the skier the roller 76 is pressed upwardly, due to upward forces exerted on the heel engaging member 134, then the spring 71 will be cornpressed during a first part of this movement. The counterpressure of the spring 71 increases therefore. Since, however, the lever 60 is turnable mounted on the bolt 41 and the guide rod 70 of the spring 71 is turnably mounted by means of the fork 72 on the bearing sleeve 47 of the link member 35, there will result during turning of the two bolts 62 and 46, against which the spring 71 abuts, about the bearing bolt 41, a reduction of the acting lever arm for the force of the spring 71, which in the position shown in FIG. 3 tends to turn the lever 60 in clockwise direction about the bearing bolt 41. The system may be designed in such a manner that during upward movement of the roll 76 the acting lever arm of the spring 71 decreases more than the spring pressure increases so that the closing moment decreases with increasing upward movement of the roller to thereby assure a sudden release of the heel during a fall.

In order to bring the heel engaging unit from the downhill run position, as shown in FIG. 3, to a walking or cross-country skiing position, the lever `60 is lifted by hand or by the plate of the ski pole to the position shown in FIG. l. The roller 76 is thereby disengaged from the locking portion 126 of the member 107 and the spring 71 is released. The outwardly bent portions 81 on the lever 60 will engage with the top portion of the cap-shaped member 39 to limit the turning movement of the lever 60. The two rollers 74 are moved over the noses 181 of the member 107 so that the latter may turn about the axis of the bearing `bolt 41 and so that the members 92 and 134 are also turned about the bearing bolt 41, while the turning movement is produced by the link members 130. Due to the disengagement of the roller 76 from the locking portion 126, the upper part of the unit may swing about the link arms 35 and 37 so that the cap-shaped member 39 with the elements connected thereto may be swung upwardly to the position as shown in FIG. l and again downwardly to the position as shown in FIG. 3. This position of the lever permits therefore during walking to tilt or roll the sole of the ski boot on the top surface of the ski 2. Thereby the members 92 and 134 will move substantially on a circular arc, the turning axis of which is located between the front unit of the ski binding and the heel engaging unit, preferably in the region of the toes of the skier, so that the distance between the portion of the member 107 and the portion 142 of the member 134 will remain substantially constant and so that during this movement there will practically be no relative movement between the heel and the heel engaging portions which would result in damage to the ski boot.

The members which engage the heel of the ski boot will, due to the circular movement of the heel engaging means not change the position relative to the heel. This result is obtained in the following manner:

During movement of the lever 60 from the position shown in FIG. 3 to the position shown in FIG. 1, the two rollers 74 which are mounted on the lever are moved over the two noses 118 of the member 107. The noses 118 are therefore held onto the bearing bolt 41, which prevents an upward tilting of the link members 84 since the pin 124, extending through the bores `88 and lixed at the outer ends thereof to the member 107, will prevent such movement. The two noses 11S of the member 107 are formed in such a manner that during movement of the lever 60 to the position shown in FIG. 1 the bottom edge faces 122 of the noses 118 are tightly pressed against the bearing bolt 41 even if such a tight engagement should initially be prevented by snow accumulations or the like.

The above-described substantially circular movement of the heel engaging means, that is the members 92, 107 and 134, is obtained in the construction shown in the drawing by connecting the mem-ber 107 to the shorter link member 37 by means of the link members 130'.

The substantially circular movement of the heel engaging means can, however, also be obtained in the following manner:

(a) The link members may also be connected at the rear ends thereof to the longer link member 35 instead to the shorter link member 37 (FIG. 9).

(b) Instead of the link members 130, a roller or a slide member may be connected to the lower portion of the member 107 and this roll or slide member may be guided along a path which preferably is in the form of an upwardly extending circular .arc 107 (FIG. 10).

(c) The members 130 may be lixedly connected or 'be integrally formed with the member 107 and provided at the rear ends thereof with slots in which rollers or guide members are arranged which are mounted on a rearwardly extended portion of the link arm 35 or on an elongated portion of the link arm 37 (FIG. ll).

During lifting of the lever `60 to the position shown in FIG. 1 the link members 84 are maintained in a stable locking position in which the common axis of the short shafts 86 is located below a horizontal line `passing through the axis of the bearing bolt 41, and therefore the heel of the ski boot will not be released during movement of the elements of the unit to the position shown in FIG. l. The forces of the heel of the ski boot which are transmitted to the link members 84 tend to turn the latter to an even further stable position.

The longitudinal pressure produced by the compression springs 19 and 21 hardly changes due to the substantially circular lifting movement of the heel 4 so that any wear on the rails S will `be relatively small. By means of spacer discs, which may be inserted between the top surface in the ski and the base plate 1, it is possible to vary the position of the mentioned circular movement to obtain, during use of ski boots of different size, the same relationship 4with regard to the longitudinal pressure produced by the springs 19 and 21.

Since the longitudinal pressure during lifting of the heel remains substantially constant, the resistance against lifting of the heel will be very small, since only frictional forces will have to be overcome. This is especially advantageous during use of the ski binding for cross-country skiing. The change-over from the position shown in FIG. 1 for cross-country skiing to the downhill run position shown in FIG. 3 is produced by downward pressure on the handle portion 82 of the lever 60.

Rubber buffers 40 connected to the inner surface of the cup-shaped member 39 at the rear end of the latter by bent-over flaps integral with the member 39 form resilient abutments for the link member 37 during crosscountry skiing.

In order to bring the heel engaging unit into the step-in position as shown in FIG. 2, the lever `60 is lifted from the position shown in FIG. 3 until the roller 76 abuts against the portion 56 of the cam S5 on the lower bearing bushing 51 of the longer link arm 35, and thereafter pulling on the yoke 138 on the member 92 so that the latter, together with the member 134, is lifted and tilted backwardly to the position shown in FIG. 2.

By moving the lever `60 to an intermediate position as shown in FIG. 4, the outwardly bent portions or limiting means 81 on the lever 60 will abut against the lower bearing bushing 51 limiting thereby downward movement of the heel engaging means so that the latter may not move to the position shown in FIG. 3, which is especially desirable during use of the ski for upward walking on steep slopes.

The mova-ble upper part of the heel engaging unit can be removed from the ski 2 while leaving the base plate 1 connected thereto. In order to remove the upper part of the unit from the ski it is only necessary to disengage the adjusting screw 17 from the base plate by screwing the screw 17 rearwardly and afterwards the whole upper part of the unit may be slid rearwardly along the guide rails 5 and removed from the -base plate 1. If the skier has several pairs of skis, it is only necessary to obtain base plates 1 vfor each pair of -skis and to mount then the upper part of the unit on the respective base plate. For skis to be rented, it is preferred to obtain longer base plates 1 to provide for a greater adjustability so that the unit may be used for ski boots of different size. In the downhill run position the adjusting screw 17 is protected by the cap-shaped member 39 and an adjustment of the screw 17 is possible only when the unit is in the walking position. Furthermore, due to the specific configuration of the lever and the cap-shaped member 39 as shown in the drawing, the whole unit has a closed and pleasing appearance. Due to the pressure of the springs 19 and 21, the threads of the adjusting screw 17 are in tight frictional engagement with the threads 27 on the base plate so that an inadvertent turning of the adjusting screw is prevented.

It will 4be understood that each of the elements described above, or two or more together, may also find a `useful application in other types of heel engaging units for a safety ski binding differing from the types described above.

While the invention has been illustrated and described as embodied in a heel engaging unit for a safety ski binding adjustable between a downhill run position and a cross-country skiing position, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

What is claimed as new and desired to tbe secured by Letters Patent is:

1. A heel engaging unit for a safety ski binding adapted to cooperate with a front unit of the ski binding for pressing a front portion of a ski boot into the front unit of the ski binding, said heel engaging unit comprising support means adapted to be mounted on a ski rearwardly of the front unit thereon; heel engaging means constructed and arranged to automatically engage the heel of a ski boot when the user steps with the heel into said heel engaging means; and linkage means connecting said heel engaging means to the support means, said linkage means extending rearwardly of said heel engaging means and guiding said heel engaging means movably relative to the ski along a predetermined portion of a substantially circular path having its turning axis in the region of the top surface of the ski and adjacent the front unit of the ski binding so that during use of the ski binding for walking said heel engaging means remains substantially non-shiftably connected to the heel of the ski boot.

2. A heel engaging unit as defined in claim 1, wherein said linkage means comprises a first parallelogram guide including an elongated member having a front portion and a rear portion, and a pair of first link means respectively pivotally connected at opposite ends thereof to said support means and said elongated member in the region of the rear portion of the latter, and a second parallelogram guide including a pair of second link means, one of said second link means being pivotally connected at one end thereof to one of said first link means and at the other end thereof to said heel engaging means, and the other of said second link means lbeing pivotally connected at one end thereof to said elongated member in the region of the front portion of the latter and at the other end thereof to said heel engaging means.

3. A heel engaging unit as defined in claim 2, wherein said heel engaging means includes a first heel engaging member having a first heel engaging portion adapted to engage an upper face of a rim portion on the heel of the ski boot, a second heel engaging member having a second heel engaging portion adapted 'to be engaged by a bottom face of the heel, said first and second heel engaging members being connected to each other movable between a step-in position in which said second heel engaging portion projects forwardly beyond said first heel engaging portion, and an engaging position in which said heel engaging portions are spaced from each other a distance smaller than in said step-in position, said heel enaging portions being brought to said engaged position by pressing the bottom face of the heel against the second heel engaging portion.

4. A heel engaging unit as defined in claim 3, and including locking means cooperating with said heel engaging members for locking the Same in said engaged position.

5. A heel engaging unit as defined in claim 4, wherein sald locking means include lever means pivotally mounted on said elongated member movable between a first position in which said lever means cooperates with said heel engaging means for maintaining the same in a doWnhill run position in which said second heel engaging member is maintained closely adjacent the top surface of the ski, and a walking position in which said heel engaging means may move along said circular path.

6. A heel engaging unit as defined in claim 5, wherein said lever means include a rst engaging portion cooperating with said heel engaging means in said first position of said lever means for maintaining said heel engaging means in said downhill run position, and a second engaging portion cooperating with said heel engaging means in said second position of the lever means for permitting said heel engaging means to move along said circular path while maintaining said heel engaging members in said engaged position.

7. A heel engaging unit as defined in claim 6, wherein said first and second engaging portions are constituted by rollers turnably mounted on said lever means.

8. A heel engaging unit as defined in claim 3, and including eccentric means cooperating with said heel engaging members for moving the same relative to each other to said engaged position during exertion of pressure on said second heel engaging portion.

9. A heel engaging unit as defined in claim 8, wherein said eccentric means includes a first member turnably about a first axis and engaging one of said heel engaging members, and a second member carried by said first member and having an axis arranged eccentrically with respect to said first axis and engaging the other of said heel engaging members, the distance between said axes determining movement of said heel engaging members relative to each other.

10. A heel engaging unit as defined in claim 9, wherein said first member of said eccentric means is carried by said other of said second link means in the region of the other end thereof and turnably about said first axis.

11. A heel engaging unit as defined in claim 3, wherein said second heel engaging member has a rearwardly projecting locking portion, and including locking means cooperating with said locking portion for releasably maintaining said heel engaging means in a downhill run position in which said heel engaging members are in said engaged position and in which said heel engaging portion of said second heel engaging member is located adjacent the top surface of the ski.

12. A heel engaging unit as defined in claim 11, wherein said locking means comprise a lever pivotally mounted on said elongated member turnably between a plurality of positions, and a roller carried by said lever and engaging in one of said positions of said lever said locking portion for releasably maintaining said heel engaging means in said downhill run position.

13. A heel engaging unit as defined in claim 12, and including spring means cooperating with said lever and being biased to yieldalbly maintain the latter in said one position thereof, said lever being movable against the force of said spring means to a releasing position in which said roller is disengaged from said locking portion upon lifting of the bottom face of the heel from said second heel engaging portion and simultaneously exerting a predetermined upward pressure against said first heel engaging portion.

14. A heel engaging unit as defined in claim 13, wherein said spring means are connected at one end thereof to said lever and at the other end thereof to said one of said pair of first link means.

15. A heel engaging unit as defined in claim 13, wherein said roller cooperates with said locking portion of said second heel engaging member in such a manner to cause, upon lifting of the heel from said second heel engaging portion and simultaneously exerting upward pressure against said first heel engaging portion, first an increased stressing of said spring means, and after said locking portion engages a predetermined point of said roller, relaxing of said spring means.

16. A heel engaging unit as defined in claim 1S, wherein said spring means is mounted and connected to said lever in such a manner that during movement of said lever from said one to said releasing position, the lever arm of the force component of the spring means which resists turning of the lever to said releasing position will continuously decrease so that the moment necessary to turn said lever to said releasing position decreases while the stress of said spring means increases during a rst part of the turning movement of the lever from said one to said releasing position.

17. A heel engaging unit as defined in claim 13 and including additional spring means acting substantially in longitudinal direction of the ski and being arranged and constructed to assist, when said lever is in said one position thereof, the action of said first mentioned spring means to maintain said lever in said one position thereof.

18. A heel engaging unit as defined in claim 17 and including adjusting means for adjusting the force of said additional spring means.

19. A heel engaging unit as defined in claim 17, wherein said support means includes a base plate adapted to be mounted on the ski, a frame mounted on said base plate movable in longitudinal direction of the ski, said additional spring mean-s being connected to said base plate and sa-id frame and being biased to resist rearward movement of said frame relative to said base plate, said pair of first link means being pivotally connected at one of the opposite ends thereof to said frame.

20. A heel engaging unit as defined in claim 19, wherein said additional spring means includes a pair of springs aligned with each other substantially in longitudinal direction of the ski, and an abutment member located between and engaged by opposing ends of said pair of springs and movable in said direction, said lever engaging in said one position thereof said abutment member in such a manner so as to increase the force holding said lever in said one position.

21. A heel engaging unit as defined in claim 12 and including stop means engaging said lever in said one position thereof for determining in said one position of the lever the position of said roller relative to said engaging portion.

22. A heel engaging unit as defined in claim 21, wherein said stop means includes a screw threadingly connected to said elongated member for adjusting said one position of said lever.

23. A heel engaging unit as defined in claim 5 and includ-ing limiting means cooperating with said heel engaging means for limiting downward movement of said heel engaging means so as to maintain said heel engaging means in said walking position above said downhill run position.

24. A heel engaging unit as defined in claim 23, wherein said limiting means are mounted on said lever means and engaging a part on said support means during downward movement of said heel engaging means to limit further downward movement of the latter.

25. A heel engaging unit as defined in claim 3, and including means on said second heel engaging portion for securing there to a member upwardly projecting therefrom for assuring proper engagement of the heel with said second heel engaging portion.

26. A heel engaging unit as defined in claim 3, wherein said first heel engaging member has at least one guide face for guiding a heel onto said second heel engaging portion.

27. A heel engaging unit as defined in claim 3, wherein said first heel engaging member includes a first component provided with said first heel engaging portion, a second component connected to said other one of said second link means, and means for adjustably connecting said first and second component to each other for adjusting the position of said first and second heel engaging portions in said engaged position of said heel engaging members relative to each other.

28. A heel engaging unit as defined in claim 1, wherein said heel engaging means includes a first heel engaging member having a first heel engaging portion adapted to engage an upper face of a rim portion of the heel of a ski boot, a second heel engaging member having a second heel engaging portion adapted to be engaged by a bottom face of the heel, said first and second heel engaging members being connected to each other movable between a step-in position in which said second heel engaging portion projects forwardly beyond said first heel engaging portion and an engaged position in which said heel engaging portions are spaced from each other a distance smaller than in said step-in position, said heel engaging portions being brought to said engaged position by pressing the bottom face of the heel against said second heel engaging portion, and guide means connected to one of said heel engaging 13 members for guiding the same along a substantially circular path.

29. A heel engaging unit for a lsafety ski adapted to cooperate with a front unit of the ski for pressing a front portion of a ski boot into the front unit of the ski binding, said heel engaging unit comprising a lirst quadrangnlar guide linkage including a support member adapted to be mounted on the ski rearwardly of the front unit thereon, a pair of rst link means having lower ends pivotally connected spaced from each other to said support member, and an elongated member having a rear portion to which upper ends of said pair of first link means are pi-Votally connected; heel engaging means constructed and arranged to automatically move to a closed position gripping the heel of a ski boot when the user steps with the heel into the heel engaging means; a pair of second link means, one of said second pair of link means being pivotally connected at one end thereof to one of said rst pair of link means and at the other end thereof to said heel engaging means, and the other of said second pair of link means being pivotally connected at one end thereof to said elongated member in the region of a front portion of the latter and at the other end thereof to said heel engaging means so that said pair of second link means -forrrr with said heel engaging means a second quadrangnlar guide linkage; and releasable locking means cooperating with said heel engaging means for yieldably maintaining the same in said closed position and adjacent said top surface ofthe ski.

binding binding 30. A heel engaging unit as dened in claim 29, Wherein said one of said first link means is longer than the other of said first link means.

31. A heel engaging unit as dened in claim 30, wherein said heel engaging means has a locking portion, and wherein said locking means comprises lever means pivotally connected to said elongated member so as to be movable to and from a lock-ing position, an engaging portion on said lever means and engaging said locking portion of said heel engaging means when saidl lever means is in said locking position so as to maintain said heel engaging means adjacent the top surface of the ski, and spring means cooperating with said lever means and biased to yieldably maintain the latter in said locking position.

References Cited yUNITED STATES PATENTS 2,758,846 8/1956 Swensen 280-11.35 3,244,431 4/1966 Hatlapa 2SC-11.35 3,317,2.17 5/1967 Poiger 280-11.35 3,328,044 6/1967 Klarnt 280--11.35 3,333,859 8/1967 Smolka et al 28011.35

BENJAMIN HERSH, Prim-'ary Examiner. L. DANIEL MORRIS, JR., Assistant Examiner.

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