EP0035613A1

EP0035613A1 - A ski binding as well as a ski and a ski boot provided with such a ski binding

Info

Publication number: EP0035613A1
Application number: EP80300715A
Authority: EP
Inventors: Howard Ford
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-03-07
Filing date: 1980-03-07
Publication date: 1981-09-16

Abstract

A ski-binding for all modes of ski-ing is provided whereby, when the skier's weight is on the ski, relative lateral movement, both angular and translational, between boot and ski is prevented by means of the coupling underfoot of:-
One or more central longitudinal downward projections from the underface of the boot engaging within a matching longitudinal groove in the top surface of the ski parallel to the longitudinal axis of the ski.
or, conversely, A central longitudinal upward projection from the ski top engaging within a matching longitudinal groove in the underface of a thickened sole and heel of the boot.

The boot may be attached to the ski by a hinge connected at or near the toe of the boot, which locates the boot fore and aft, permits the boot to pivot up through about 90° and affords the means to provide pull and push for traction and propulsion and the means for lifting the ski in jump and kickturns.

For Downhill Racing a simple heel latch can be added to ensure that during airborne spells, when aerodynamic forces tend to lift the ski tip, the rear of the ski does not consequently drop and thereby relay the lateral constraint.

Description

The present invention relates to ski-bindings.
A versatile ski-binding must allow the heel to lift from the ski when climbing or pole-ing along on the flat, and for running downhill and slaloming must enable the boot to transmit to the ski all forces necessary for manoeuvre. Also, it should guard against caking of snow underfoot after heel lifting in soft snow, and should preferably function efficiently with a ski-boot that is flexible enough for comfortable walking as well as with the stiffer conventional plastics boot which provides stronger control, albeit at the cost of some discomfort. Moreover, a paramount requirement is that the binding should be safe.
In seeking to devise a ski-binding to take advantage of the greatly reduced control forces required for the convex-bottom ski described in British Patent Specification No. 1,505,092, U.S. Patent Specification No. 4,083,577 and others, I have found that, contrary to past and present teaching, it is not necessary for the binding to exert a strong diagonal down-pull on the heel, as given, for example, by the very popular Kandahar binding, one of the most successful evolutions of the original Huitfeldt binding: rather it is only necessary to locate the boot effectively which the old toe-irons failed to do.
Also, it is unnecessary, having located the boot effectively, as do modern bindings, to anchor it down rigidly, relying on release mechanisms to avoid bone-breaking stresses, and on auxiliary devices to prevent a ski absconding downhill when the safety release works and also to permit the heel to lift when touring.
It is simply necessary for the location of the boot to be such that the skier's weight on the ski can itself ensure locating naturally with no resort to complicated mechanisms.
According to the present invention there is provided a ski-binding comprising means for coupling a ski-boot to a ski at a boot position for the transmission of control forces for turning and other manoeuvre while allowing the heel to lift, the coupling means comprising in or on the underface of the boot and in or on the top surface of the ski at the boot position opposable surfaces which, when the boot is held resting on the ski at the boot position as by the distribution of the skier's weight between the ball and heel of the skier's foot, are in contact such that they thereby couple the boot to the ski to prevent relative movement, both angular and translational, between the boot and ski to either side of the longitudinal axis of the ski.
The ski-binding according to the invention may comprise one or more components projecting downwards from the underface of the boot which provide at least-one pair of outward facing, parallel surfaces running along the boot inwards from the sides of the underface and parallel to its longitudinal axis, and a housing in or at the top surface of the ski having side surfaces which face inwards towards and are parallel to the longitudinal axis of the ski to accomodate the one or more boot components when the boot is held resting on the ski with the respective component and housing surfaces in contact. With such a binding the housing may be provided between components attached to the ski at each side of the top surface of the ski or by raised sides integral with the ski. Alternatively, the housing may be provided within the opposite sides of a hollow body shell of a convex-bottom ski.
Conversely, the ski-binding according to the invention may comprise one or more components projecting from the top surface of the ski to provide on each side of the longitudinal axis of the ski at least one pair of surfaces facing outwards from and parallel to said axis and a housing underneath the boot having inward facing side surfaces parallel to the longitudinal axis of the boot underface to accomodate the one or more ski components when the boot is held resting on the ski with the respective said component and housing surfaces in contact.
Preferably, the boot is attached to the ski by a hinged connection at or near the toe of the boot which locates the boot fore and aft, permits the heel of the boot to lift from the ski and the boot to pivot up, and affords the means to provide pull and push for traction and propulsion and the means for lifting the ski in jump and kick turns.
The present ski-binding, devised in the first instance for the convex-bottom ski of British Specification No. 1,505,092, is fully adequate for the transmission of the much larger control forces required for skis of conventional rectangular cross-section, giving the invention wide application. It is therefore described in terms applicable to both these types of ski.
With the convex-bottom ski of British Specification No. 1,505,092 a longitudinal groove in the top surface of the ski can readily be made available between the . opposite sides of its hollow convex shell and such a groove can provide the necessary coupling surfaces in the ski. With the conventional ski of rectangular section, however, a longitudinal groove has to be created by building up side boot platforms high enough to expose inner faces of sufficient depth for effective engagement.
As indicated above, conversely for both such types of ski, a central longitudinal upward projection may be built up on the top surface of the ski at the boot position, which can be received within a housing underneath the boot.
During manufacture raised platforms can be made integral parts of the ski but they can also be incorporated by modification after manufacture. It is such retrospective modification that is mainly used in examples in the specific description herein, which refers to the convex-bottom ski only to the extent necessary to pin-point certain differences of detail.
In the preferred ski-binding according to the invention the rigid and precise underfoot coupling of boot and ski, which provides the means for transmitting the major control forces for turning and other manoeuvring, is in conjunction with a transverse hinged connection of boot to ski near the toe of the boot, the pivot of which provides the fore and aft location of the boot and permits the boot to pivot up, preferably through a full 90°, and also affords the means to provide pull and push for traction and propulsion and the means to lift the ski in jump and kick turns; and, provided that it is positioned behind the centre of gravity of the ski, will give rise to a "front-heavy" gravity couple to maintain the engagement of the underfoot coupling when the ski is unweighted by lifting, e.g. in jump turns.
For Downhill Racing, however, when the contours often launch the skier willy-nilly into the air and strong aerodynamic forces will tend to lift.the ski tips, the addition of a simple attachment to prevent the rear of the ski from dropping will be advisable. One such device to be described later is a spring-loaded heel latch fitted to the ski immediately behind the boot. It gives the necessary lift to the rear of the ski and also provides a useful aid to fore and aft balance when the skier is crouching low to minimise wind resistance.
If it is desired to avoid stiffening the boot under the instep, so as to make it more comfortable, the boot projections can be provided in separate front and rear sections rather than continuous as that provides the same maximum leverage. Comfort of the boot for walking will also benefit from all the width that can be accorded to the inter-platform groove, but this must not exceed the capacity of the boot to bridge it without sagging and must of course leave sufficient width for the platforms themselves to provide a comfortable ski-ing stance.
It will be advantageous, logistically, to standardise the widths of the inter-platform groove and the corresponding boot projection.
Making each of the side boot platforms in one piece, instead of sometimes in sections as with the boot projections, has the advantage of simplifying fixing and alignment when modifying a conventional ski, while when incorporated during production of a ski their strength in bending will permit part of the depth of the inter-platform gap to be provided by longitudinal grooving of the top face of the ski: and for both these versions it also has the advantage of preventing ingress of snow from the sides.
Although a transverse hinge pivot near the toe of the boot is now customary for bindings catering for the touring mode, the method of attachment here may differ in that cne of the hinge components, male or female, may be incorporated in the boot itself appreciably behind the toe and either under or above it.
Exactly where the pivot should be positioned along the boot depends on several considerations. On the . one hand the further it is behind the toe of the boot the less the offset load on foot and leg muscles when lifting the ski in jump and kick-turns: but on the other hand the further it is in front of the ball of the foot the better (as explained later) for the skier's fore and aft balance. Furthermore, if the pivot is too close to the ball of the foot the under-foot boot/ski coupling would sometimes be lifted out of engagement - a welcome enough safety feature when a forward fall is actually in process but most unwelcome if occurring prematurely. In addition the method of attachment of the boot to the pivot must of course be strong and durable.
Overall, these considerations suggest that the best compromise position for the pivot will probably be approximately level with the ball of the big toe within the boot.
The boot alterations entailed by the invention such as the under-foot projections and the under- or above-toe hinge components, are of course best incorporated during the manufacture of the boot. Like those for the conventional ski, however, they can'also be applied after manufacture and so modification kits for both boot and ski can be provided.
LANGLAUF ski-ing constitutes a special case in that it takes place across gently undulating country mostly in prepared tracks which involve no abrupt changes in direction or of contour. Its ski-binding requirements therefore differ in some respects from those for downhill ski-ing.
The control forces needed are smaller but more accurate control is.required throughout the heel-up phase of a stride. Considerations of safety hardly arise: rather the paramount requirement is for economy of effort in every one of the thousands of strides entailed in a LANGLAUF race. This demands from the ski lightness andlow snow resistance; and from the boot and binding lightness too and unrestricted lifting of the heel to provide the fullest possible stride with minimal losses due to friction or other causes.
Most modern LANGLAUF bindings locate the toe of a light and comfortable boot in toe-irons and a flexible extension of the sole in front of the toe serves as a hinge allowing the heel to lift some 60° or so, beyond which angle, however, the rear of the ski tends to lift in an ungainly and wasteful manner.
The ski-binding according to the invention for LANGLAUF skis allows unrestricted pivoting of the boot, preferably through at least 90°, with.adequate lateral control, which when the foot is down becomes rigid control by virtue of the underfoot coupling of boot and ski according to the invention.
The invention also provides a ski-boot including in or on its underface part of the coupling means defined above and a ski including in or on its top surface part of the coupling means defined above. _The invention further provides a kit of parts to provide means for coupling a ski-boot to a ski in accordance with the invention.
The invention will now be described by way of example with reference to the accompanying drawings in which:-

Figure 1 is a cross-section near the ball of the foot of a boot of the conventional type and a modified ski of conventional rectangular cross-section showing the coupling arrangement of a ski-binding according to the invention,
Figure 2 is a cross-section near the tall of the foot of the boot and a convex-bottom ski according to British Specification No. 1,505,092 showing a coupling arrangement similar to Figure 1,
.Figure 3 is a cross-section near the ball of the foot of a boot and a modified conventional ski showing an alternative coupling arrangement,
Figure 4 is a top plan view of the boot position of a ski according to Figure 1 (but to approximately half the scale) which has a behind- and under-toe hinge bracket,
Figure 5 is a side elevation of the part ski of Figure 4 showing the boot in two positions, fully down and ball of foot down/heel slightly up,
Figure 6 is an under-view of the sole and heel of the boot when pivoted 90° above a cross-section of the part ski of Figures 4 and 5 at the hinge position,
Figure 7 is a top-plan view similar to Figure 4 except that it has a behind- and above-toe hinge bracket,
Figure 8 is a side elevation of the part ski of Figure 7 showing the front part of the boot pivoted up about 45°, .
Figure 9 is an enlarged part section of the top of the boot toe in Figure 8 showing a cross-section of the above-toe hinge,
Figure 10 is an under-view of the sole and heel of the boot when pivoted 90° above a cross-section of the part ski of Figures 7 and 8 at the hinge position,
Figure 11 is a top plan view of the boot position of a convex-bottom ski according to Figure 2 (but to approximately half the scale) and embodying the behind-and above-toe hinge bracket of Figures 7 and 8, .
Figure 12 is a top plan view of the boot position of a ski according to Figure 3 (but to approximately half the scale),
Figure 13 is a top plan view of a heel latch bracket for Downhill Racing fitted to a convex ski, and
Figure 14 is a central longitudinal section of the bracket of Figure 13 with the associated parts of boot heel and ski.

Referring to Figures 1, 4, 5 and 6, boot- platform components 1 and 2 are screwed onto the top surface of a conventional rectangular cross-section ski. These components afford built-up side boot platforms and provide a housing to accommodate downward under-foot projections. A sole projection 6 and a heel projection 13 are shown in Figures 5 and 6, while the enlarged cross-section of Figure 1 shows in more detail how projection 6 engages and couples within the gap between the projecting boot- platforms 1 and 2.
It will be seen that the projections 6, 13 and the platforms 1,2 have rounded corners 4 and 3, which in conjunction provide progressive relaxation of lateral constraint as the boot lifts and also facilitate re-engagement. Since this chamfering results in the effective depth of coupling being comparatively shallow, it is important that the boot projections should have tough sides to engage with the boot platforms. Without encroaching on their rounded outerfaces the underface of the projections can with advantage be recessed upwards as at 5 leaving a series of transverse "rungs" of suitable shape to assist grip when walking.
Below the boot under-faces is -eft a clearance 7 to guard against the caking underfoot of any snow that may have gained ingress from the sides. This clearance can be increased, if desired, or alternatively the height of the boot-platform reduced, by embodying in the course of manufacture a longitudinal underfoot groove in the top surface of the ski, the longitudinal stiffness of the platforms 1 and 2 compensating for the loss of bending strength resulting from the groove. Also, as shown at 8 there may be small lateral scoop-outs that will assist the process of dislodgement by components 1 and 2 of any snow or ice that may have caked underfoot..
Any tendency for snow to cake on the boot platforms themselves could be eradicated by a series of lateral corrugations along the length of their top faces which in side. elevation would have approximately sinusoidal form with crests about 1 cm apart and troughs about 2 mm deep, the crests constituting high pressure areas for crushing the snow and the troughs providing escape routes for extruding it (not shown).
Ingress of snow from the front can be prevented by a tongue of resilient material e.g. canvas (not shown), similar in shape to the bottom half of the hinge bracket described below with reference to Figures 7 to 10.
In front of platforms 1 and 2 is a U-shaped under-toe hinge bracket 9. Each of the arms of bracket 9 have a portion 9a as shown in Figure 5 defining a hole through which a bolt 10 can engage, providing the pivot for the boot. A packing piece 11 with shims for fine adjustment is provided to match the height of the boot holes of the arms of bracket 9 with the height of a corresponding bolt hole in the nose of the sole projection 6, the criterion being that the hole centre, in the arms should be slightly higher - say 1 to 2 mm - than the centre of the bolt hole through the sole projection 6, when the boot is resting on boot- platforms 1 and 2 so that when connected by bolt 10 the toe of the boot is just hanging from its pivot, thus providing a heel-down couple that is especially valuable when the skier's weight has come forward to the ball of the foot, making his fore and aft balance precarious.
Although a flexible boot cannot fully transmit this heel-down couple nevertheless the lift of the-pivot usefully prevents the boot from rolling forward.
The bolt 10, whose easy-to-grip handle 10(a) is permanently secured to the ski by a tie (not shown), has a tapered extremity 10(d) to facilitate insertion, and an annular groove 10(b) in which one end of a straight wire spring 10(c) engages and presses so as to retain the bolt when pushed in the other end of the spring being soldered or otherwise fixed to the outer bracket arm. A duplicate spring 10(c) if fitted on the other bracket arm, as shown in Figure 5, although redundant has the minor merit of making skis interchangeable left and right.
Figures 6 and 5 show how the-front of the -sole projection 6 as well as some of the sole above it, is cut back to form shoulders 6(a) and 6 (b). These, contacting with the upstanding portion of the arms of bracket 9, can provide a useful stop for positioning the boot prior to inserting bolt 10. If desired, the "snout" of the projection 6 (i.e. 6(a), (b) and (c))can be encased in a metal strengthening cover: furthermore, if necessary, to ensure that the bolt turns in its bearings in the bracket arms rather than within the boot the bolt holes through such a cover together with the central part of bolt 10 could be splined.
The second boot portion shown dot-dashed in Figure 5 indicates how, with a boot sufficiently flexible for comfortable walking, the sole projection 6 can remain almost completely coupled after the heel has lifted out of engagement and so on its own can transmit a large turning couple.
Figures 7 to 10 show a similarly modified conventional ski except that it embodies an alternative behind- and above-toe hinge bracket 18 and is a right ski because the bolt 19 which constitutes the hinge pivot has its handle 20 on the righthand side.
The goose-neck shape and height of the bracket 18 allows the bolt 19 to be slightly further to the rear, if desired, than the bolt 10 in Figures 4 to 6, in which case the fronts of the platforms 1 and 2 are similarly set back slightly to the rear and have well rounded corners 21 as shown in Figures 7 and 8 to avoid any catching there of the boot sole when t_Ile toe retracts as the heel lifts.
Referring to Figure 10 the heel projection 13 is the same as before but the sole projection 26 differs from projection 6 in Figure 6 not only in that the pivot 14 is absent, but also in that it has a pointed front 27 which provides a wide-angled lead-in to realign the boot after a lift. Figure 8 shows the front of the boot elevated about 45° with the front 27 of the sole projection 26 below and within the boot- platform components 1 and 2 ready to serve to lead the remainder of the sole projection in to parallel re-engagement on the.way down.
The bracket 18 is adjustable vertically by a packing piece 18c for the reason previously given and in the structure of the boot there may be strengthening re-inforcements such as indicated at 22a and 22b to secure the housing 28 of the bearing 25 discussed below.
Referring now to the enlarged cross-section of the above-toe hinge shown in Figure 9, interchangeable sleeves 23 and 24 screw respectively into side arms 18a and 18b of bracket 18 and provide means of adjustment for the lateral location of the housing 28 of bearing 25, which must conform with, and not fight, the boot location determined by its under-foot coupling.
The sleeves 23 and 24 are long enough to project appreciably beyond the sides of arms 18a and 18b and thus afford projecting external screw threads, on the outer one of which is screwed a simple bolt securing device 29. The device 29 embodies two curved strips 29a, each terminating at end 29b in a rounded knob which bears on the circumference of the bolt 19. On the bolt 19 close to the handle 20 is a smooth annular protuberance 20a which, as the bolt is pushed in, temporarily forces the spring strips 29a outwards until the knobs 29b ride over the protuberance 20a and engage behind it to secure the bolt. Withdrawing the bolt to release the boot entails the reverse process; a pull on the handle 20 forces the knobs 29b to ride up over the protuberance 20a, thus allowing withdrawal of the bolt. The handle 20 of the bolt is permanently tied to the adjacent bracket arm 18a by means not shown.
It will be seen, because shown exaggerated, that appreciable clearance is left between the sleeves 23 and 24 and the bearing 25 between them. This facilitates the engagement of the boot with the bracket and also ensures that the above-toe bearing does not fight the boot location determined by the engagement of the under-boot projections. The latter requirement is applicable.also to the under-toe hinge and it follows that both types of bracket should be fitted with the boot and ski already coupled.
It will be seen that the bearing 25 is shaped like an hour-glass which considerably reduces its effective width, already quite small, and allows the boot (when disengaged from its normal coupling with the boot-. platform) a degree of freedom about the roll and vertical axes much greater than the under-toe hinge bracket 9 could possibly provide.
This-additional angular freedom constitutes a valuable safety feature of the above-toe hinge which is also more conveniently accessible and is less restricted in diameter so that the bearing 25 could be of a replaceable self- lubricating type, such as "oilite", in which graphite is impregnated, giving welcome reduction in friction.
It would be possible, of course, to increase its angular freedom still more by turning bracket 18 into a universal joint but this extreme is not favoured as at least a modicum of angular control about the roll and vertical axes is still required when the under-boot projections are out of engagement e.g. in a kick-turn.
While this above-toe bracket offers these marginal advantages, nevertheless the greater simplicity of the under-toe bracket and its boot modifications may well outweigh them.
Figures 2 and 11 relate to the unorthodox convex-bottom ski of British Specification No. 1,505,092. Figure 2, comparable with Figure 1 shows that upward projecting side boot-platform components do not have to be separately provided. Here the ski body can be a hollow shell 32, the sides of which are supported by and integral with metal edge-blades 31 affixed either side along the centre section of the ski at the boot position. The opposite inner faces of the hollow shell provide the sides of the longitudinal groove within which the downward boot projections couple.
The pairs of corners 4 and 3 are as before and-the sole projection 26 is similar to that of Figure 10 except that it may be slightly wider as is the ski itself. The under-boot clearance is also rather greater than clearance 7 of Figure 1 because of the convexity of the ski-body shell 32.
Figure 11, corresponding to Figure 7, shows a top plan view of the convex-bottom ski fitted with the. above-toe hinge bracket 18. Approximately between the front and rear fixing screws of the bracket 18 is a cross-bracing member (not shown) and this together with another cross-bracing member 36 behind the heel can conveniently provide the two main strong points for the attachment to the body shell of the edge blades 31 and the necessary structural stiffening to withstand the side loads on the inner faces of those blades when resisting skidding.
A third cross-bracing member 35 (shown in dashes) may if desired be added when catering for the flexible boot, but for the stiff-soled plastics boot member 35 is better omitted so that the under-foot projection can be in one continuous piece.
In front of the bracket 18, and also behind the cross-bracing member 36, is shown a foam filling 34 that prevents the accumulation of snow throughout the length of the ski's hollow top, except in this underfoot part of the centre-section to which ingress of snow from the front is prevented by the bracket 18 and for most of the time by the boot above. However, snow is bound to enter sometimes when the heel is lifted in soft snow, so an exit 37 is provided whereby such snow can be ejected by pointing the ski vertically upwards (as if half way through a kick turn) and banging its rear end down.
Referring now to Figures 13 and 14 which show the heel latch bracket for optional use when racing downhill, it will be seen that a bracket 51, fixed to the ski immediately behind the boot heel 50 by screws 52, embodies two pivots, 54 and 56, carrying respectively a heel latch 53 and its selector lever 55. Fixed to the back of boot heel 50 by screws 59 is a rearward projection 58, the top face of which forms a ledge, sloping downwards some 20° to 30° from the horizontal, with a rounded rear extremity. Connecting latch 53 and selector lever 55 is a tie 57 and a spring 60. The selector lever-55 as shown in its forward position where, as also in its rearward position, it is secured by some form of "click-on" device (not shown). In the forward position the tie 57 is slack and the spring 60 is fully tensioned and is loading the nose of the latch 53 against the heel ledge, thus supporting the rear of the ski when airborne.
When the selector lever 55 is withdrawn (by hand or with a poke by a ski pole) the tie 57 tautens and withdraws latch 53 clear of the heel ledge and holds it back out of use.
The spring tension and the shape of the contacting faces of latch 53 and ledge 58 in conjunction with the downward slope of the latter govern the forces resulting from their engagement. These are chosen to be not large enough to prevent the heel from lifting in a fall but, within this safety limitation, to provide a substantial heel-down pull to assist fore and aft balance when crouching low to minimise wind resistance.
The bottom rear corner 61 of the boot heel, is bevelled to merge smoothly with the curved underface of the heel projection 58, and the top face of latch 53 has complementary curvature, allowing the heel to be stepped back into re-engagement after a heel-lift.
Considering now the LANGLAUF variant of the present ski-binding, it should be borne in mind that when the ski is unweighted it is the transverse hinge that controls direction and is responsible for drawing the rear ski through to the front in accurate alignment with the track. The underfoot boot/ski coupling in its turn has the complementary responsibility for controlling the ski when the skier's weight is down on the ski and for providing any turning torque then required: and it also helps indirectly in that the hinge, relieved of. any major load in this phase of the stride, can employ more delicate low-friction bearings for its pivot.
In the construction of a LANGLAUF binding in accordance with the invention it suffices that the coupling of ski and under-boot should extend only as far back as the ball of the foot as that will provide ample torque for turning, and in that case the gap between the platforms at the heel position would be bridged to provide a comfortable seating for the soft heel of the boot.
Because the boot must be very light its structure cannot easily accomodate either ετ above-toe or an under-toe hinge pivot and this is therefore moved forward to immediately in front of the toe. The bracket is now full-width across the ski and can embody each side for recreational ski-ing a low-friction plain bearing of the "oilite" type already mentioned, and a good quality bolt can provide the pivot, with a simple tie to retain it when undone.
For competitive racing the still lower friction of roller bearings would probably be worthwhile.
. Referring finally to Figures 3 and 12, which relate to the alternative coupling arrangement for a modified conventional ski, it will be seen that the central upward projecting component 40 can be considerably narrower than the corresponding downward projection 6 of Figure 1 which is wide enough for comfortable walking: component 40 can certainly.be narrow enough to constitute a standardised width for all sizes of conventional skis. The chamfered corners 3 and 4 for the lead-in are as before and at 42 there is shown the appreciable clearance that is necessary above the two projecting flanges.31 of component 40 in order to prevent interference with the proper seating of the boot on its platform below. Also shown at 8, but now above rather than below as in Figure 1, are small lateral scoop-outs, that will assist in the process of dislodgement by the two flanges of component 40. of any snow or ice that may have formed in the boot groove while.walking.
Referring to Figure 12, the upward projecting central longitudinal component 40 can be seen screwed onto the ski top with its two side flanges 31 with chamfered top corner 3 on either side of its hollowed out body 43. At the front end of component 40 the flanges 31 become more substantial (and can if desired be curved slightly upwards in side elevation to match the height of the toe of the boot) in order to provide strong bearing arms 44 for the pivot 45 which attaches the boot to the ski behind and under the toe, a tie 46 being provided to retain the pivot when withdrawn. Preferably the pivot keys into the boot so as to rotate with it in bearings within the arms 44 which can as before be of the "oilite" type.
The handle 47 of the pivot must be readily accessible to gloved fingers and easily withdrawable so that in a dire emergency (for example when threatened by an avalanche) the boot can be quickly freed from the ski. This safety requirement is equally applicant to the hinge brackets of Figures 4 to 6 and of Figures 7 to 11.
Not shown, at the ball of the foot and heel positions are the possible lateral corrugations already referred to which might prove desirable to assist the disposal of any snow trapped underfoot after a heel raise. In this case the grooves for the extrusion of such snow would deepen towards the ski sides, increasing in depth from about 1 mm outside flanges 31 to about 3 mm at the ski sides.

Claims

1. A ski-binding comprising means for coupling a ski-boot to a ski at a boot position for the transmission of control forces for turning and other manoeuvres while allowing the heel to lift, the coupling means.comprising in or on the underface of the boot and in or on the top surface of the ski at the boot position opposable surfaces which, when the boot is held resting on the ski at the boot position as by the distribution of the skier's weight between the ball and heel of the skier's foot, are in contact such that they thereby couple the boot to the ski to prevent relative movement, both angular and translational, between the boot and ski to either side of the longitudinal axis of the ski.

2. A ski-binding according to claim 1 comprising one or more components projecting downwards from the underface of the boot which provide at least one pair of outward facing, parallel surfaces running along the boot inwards from the sides of the underface and parallel to its longitudinal axis, and a housing in or at the top surface of the ski having side surfaces which face inwards towards and are parallel to the longitudinal axis of the ski to accomodate the one or more boot components when the boot is held resting on the ski with the respective said component and housing surfaces in contact.

3. A ski-binding according to claim 2, wherein the housing is provided between components attached to the ski at each side of the top surface of the ski or by raised sides integral with the ski.

4. A ski-binding according to claim 2, wherein the housing is provided within the opposite sides of a hollow body shell of a convex-bottom ski.

5. A ski-binding according to claim 1 comprising one or more components projecting from the top surface of the ski to provide on each side of the longitudinal axis of the ski at least one pair of surfaces facing outwards from and parallel to said axis and a housing underneath the boot having inward facing side surfaces parallel to the longitudinal axis of the boot underface to accomodate the one or more ski components when the boot is held resting on the ski with the respective said component and housing surfaces in contact.

6. A ski-binding according to any one of the preceding claims, wherein the boot is attached to the ski by a hinged connection at or near the toe of the boot which locates the boot fore and aft, permits the-heel of the boot to lift away from the ski and the boot to pivot up, and affords the means to provide pull and push for traction and propulsion and the means for lifting the ski in jump and kick turns.

7. A ski-binding according to claim 6, wherein the hinged connection is such that the boot can pivot up from the ski through an angle of about 90°.

8. A ski-binding according to claim 6 or claim 7, wherein the hinged connection is positioned behind the centre of gravity of the ski so that when and as the ski is lifted a gravity couple is provided to maintain the engagement of the boot and ski coupling.

9. A ski-binding according to any one of claims 6 to 8, wherein the hinged connection comprises a plurality of inter-connectable components one of which is attached to the boot and another of which is attached to the ski.

10. A ski-binding according to any one of claims 6 to 9, wherein the pivot of the hinged connection is be ind and above the toe of the boot when the boot is coupled to the ski.

11. A ski-binding according to any one of claims 6 to 9, wherein the pivot of the hinged connection is behind and underneath the toe of the boot when the boot is coupled to the ski.

12. A ski-binding according to any one of the preceding claims, wherein the corners of the engaging surfaces which first meet when boot and ski are coupled underfoot are chamfered to facilitate coupling and to provide smoothly . progressive-relaxation of lateral constraint when uncoupling.

13. A ski-binding according to any one of the preceding claims which includes a spring loaded heel latch fixed to the ski behind the boot heel and the boot heel includes'a rearwardly projecting portion engageable with the latch whereby the rear of the ski is prevented from dropping when airborne but the boot is able to lift in a fall.

14. A ski-binding substantially as hereinbefore described with reference to and-as illustrated in Figures 1 to 12 of the accompanying drawings.

15. A ski-binding substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

16. A ski including in or on its surface at the boot position part of the coupling means defined in any one of claims 1 to 12 or 14.

17. A ski-boot including in or on its underface part of the coupling means defined in any one of claims 1 to 12 or 14.

18. A kit of parts to provide means for coupling a ski-boot to a ski according to any one of claims 1 to 12 or 14.