Release ski binding

A release ski binding having a sole plate which is pivotal about a vertical axis and about a transverse axis, which sole plate is held on the ski by a resilient holding mechanism in the skiing position. The holding mechanism effects in response to a movement of the sole plate relative to the ski and upon reaching a predetermined angle of traverse, both an upwardly and also a side opening of a locking mechanism. The resilient holding mechanism is formed by a U-shaped spring member having a bearing thereon arranged in the region adjoining the legs of the U. The spring member is adjustable and securable in the longitudinal direction of the ski with respect to the locking mechanism. A sliding member is arranged between the legs of the U, which sliding member is secured to and movable with the sole plate.

FIELD OF THE INVENTION 
This invention relates to a release ski binding having a sole plate which 
is pivotal about a vertical axis and about a transverse axis, which sole 
plate is held on the ski by a resilient holding mechanism in the skiing 
position, which holding mechanism effects, in response to a movement of 
the sole plate relative to the ski and upon reaching a predetermined angle 
of traverse, both an upwardly and also a side opening of a locking 
mechanism. 
BACKGROUND OF THE INVENTION 
Such release ski bindings are described in German Patent No. 2 533 337. In 
these conventional ski bindings the spring of the holding mechanism acts 
through a piston onto an approximately mushroom-shaped follower member, 
which is supported swingably to all sides in the housing of the holding 
mechanism. The stem portion of the mushroom-shaped follower member is 
received in a recess of a ski-fixed fitting. The ski shoe is, in these 
conventional ski bindings, held at its tip or toe by means of a rigid bar 
on the sole plate. The bar, however, prevents during a twisting fall the 
release of the ski shoe to a certain degree. 
This disadvantage is avoided in the ski binding according to German Patent 
No. 2 324 078, however, this ski binding is very complicated in its 
design. In addition, in this ski binding the adjusting of the release 
moment is accomplished by two check nuts housed inside of the binding 
housing and, therefore, are accessible only after removing the housinglike 
front jaw from the ski. Therefore, the adjusting task can be accomplished 
only with difficulties. 
The goal of the invention is to overcome the mentioned disadvantages of the 
conventional designs and to provide a release ski binding of the 
above-mentioned type, which is simple in its design and which can be 
adjusted easily externally of the ski binding to the desired release 
moment. 
This goal is inventively attained primarily by providing a resilient 
holding mechanism being in the form of a U-shaped spring member having a 
bearing arranged in the region whereat the legs of the U are joined 
together. The spring member is securable as well as being adjustable in 
the longitudinal direction of the ski and with respect to the locking 
mechanism. The slide member is located between the legs of the spring 
member and is fastened to the sole plate at its upper end. Of course, the 
adjustment of the bearing could also occur against the action of a spring 
through a wedge or the like adjustable in the transverse direction of the 
ski as for example by a screw. However, it has been proven to be 
particularly advantageous to construct the bearing as a pin arranged on a 
travelling nut arranged on a screw which extends in the longitudinal 
direction of the ski. This enables it to be possible to adjust the desired 
release moment particularly sensitively. 
Furthermore, the invention provides for the spring member to be arranged 
within a housing. The screw has at its end remote from the nut a part 
which is rotatably supported in a narrow sidewall of the housing, however, 
is secured against axial movement. The housing is secured below the sole 
plate on the ski. This measure ensures, on the one hand, a protected 
housing and an external accessibility of the screw located inside the 
housing and, on the other hand, preventing an undesired rotating of the 
screw under the influence of external forces. The further inventive 
characteristics lead also in this direction, namely, that for supporting 
the screw in the narrow sidewall of the housing the screw is provided with 
a flange and with a groove, whereby a snap ring is received in the groove, 
or that the screw is provided on its end projecting from the housing with 
a noncircular end, to facilitate engagement with a tool, such as a wrench. 
In order to assure a reliable support of the spring member in all operating 
positions, it is inventively provided that the spring member is supported 
in the area of the free ends of its legs on a cross brace which extends 
transversely with respect to the longitudinal direction of the ski and 
parallel with respect to the upper surface of the ski, or that the spring 
member is centered in the skiing position of the ski binding relative to 
the vertical longitudinal center plane of the ski by a stop secured to the 
housing and extending between the ends of the two legs. 
Actually it would by all means be possible to provide an enlarged head on 
the sliding member with semispherical projections, which engage 
correspondingly formed recesses in the legs of the spring member. However, 
it has proven to be particularly advantageous, if according to a further 
development of the invention the head of the sliding member has two 
upwardly converging surfaces with which are associated correspondingly 
formed surfaces on the underside of the two legs of the spring member. 
In order to couple the spring member with the locking mechanism for the ski 
shoe, two plate-shaped control members for the control mechanism are 
arranged between the underside of the sole plate and the upper side of the 
housing, which control members are constructed as two-arm levers and are 
pivotal about a pin which is secured on the upper side of the housing and 
are coupled with the two legs of the spring member. Actually it would be 
possible to equip the control members with downwardly projecting pins 
extending through slotted holes in the upper side of the housing and being 
received in slotted holes, which extend in the transverse direction of the 
ski, in the two legs of the spring member. However, it has been proven as 
being particularly advantageous for the control members to have downwardly 
extending bent sections in the region of their arms adjacent the legs of 
the spring member, which bent sections extend through arc-shaped recesses 
in the upper side of the housing and rest on the outwardly facing sides of 
the two legs of the spring member. It is thereby preferable if the two 
control members are under the influence of a spring which urges the bent 
sections on the legs of the spring member together. 
In order to assure a synchronous movement in opposite directions of the two 
control members during twisting falls, the invention includes the 
provision of link members hingedly connected to the arms of the control 
members having the bent sections thereon, which link members are connected 
by a pin guided in a slotted hole in the upper side of the housing and in 
a slot in a shoulder on the housing. 
In order to hold the ski shoe on the sole plate, two pairs of bearing 
blocks are arranged on the end of the sole plate closest to the tip of the 
ski, on which bearing blocks are secured axles on which are supported 
angular or two-arm clamping jaws with slotted holes therein. According to 
another characteristic of the invention, a control plate is guided in the 
vertical direction for movement between each pair of bearing blocks, which 
control plate has in its lower half a groove which opens toward the 
vertical longitudinal center plane of the ski and which is approximately 
trapezoidal in cross section. At least one projection is arranged on each 
control member, which projection extends into the groove in the skiing 
position of the ski binding. This characteristic of the invention 
contributes to a reliable locking of the clamping jaws in the skiing 
position. A further characteristic of the invention leads also in this 
direction, namely, that each clamping jaw has two recesses in the lower 
lever arm which lies opposite the clamping arm, of which recesses the one 
serves, in the skiing position of the ski binding, to receive a projection 
of the sole plate and the other one for receiving the upper end of the 
control plate. It is thereby preferable if each control plate is under the 
influence of a spring which urges it upwardly or if each clamping jaw has 
an outer surface which extends approximately parallel with respect to the 
longitudinal axis of the slotted hole, which outer surface serves as 
bearing surface for the upper end of the associated control plate in the 
stepping-in position of the ski binding. 
Of course it would be possible to bring about the opening of the ski 
binding by a cam disk pivotal about an axis which is vertical on the upper 
side of the ski and which during manual rotation spreads apart the two 
control members. However, it has been proven as being preferable to 
provide an enlargement through which extends a bolt in the transverse 
direction of the ski, and to provide an axle arranged on the shoulder in a 
bearing block, on which axle is supported a two-arm release lever having a 
lower, U-shaped constructed arm resting on the ends of the bolt. This 
construction permits an opening of the ski binding by means of the ski 
pole, whereby the force which is needed for the opening is kept within the 
usual limits. 
Finally it is preferable for the head of the sliding member to have on both 
sides thereof a groove which is wedge-shaped in cross section, into which, 
in the skiing position, is received a correspondingly formed leg of the 
spring member, which is approximately trapezoidal in cross section. This 
measure permits an opening of the ski binding during a backward fall of 
the skier.

DETAILED DESCRIPTION 
A downwardly open, rectangularly shaped housing 2 is secured to the upper 
surface of a ski 1 for example by plural screws which extend through holes 
in a flange 2a encircling the housing. The screws are only schematically 
illustrated as at 2g in FIG. 2. A hole is provided in the narrow sidewall 
2b of the housing 2 and rotatably supports a screw 3 therein, which screw 
is secured against axial movement. The screw 3 has for this purpose an 
annular flange or collar 3a thereon and an annular groove 3b axially 
spaced from the flange and into which is received a snap ring 4. The 
narrow sidewall 2b is received between the flange 3a and the snap ring 4. 
The axial end of the screw 3, which projects outwardly from the housing 2 
has a square end 3c onto which a wrench, for example, a socket wrench 
(neither of which is illustrated), can be placed to facilitate rotating of 
the screw. The end of the screw 3 inside the housing has an externally 
threaded end thereon. 
A nut 5 is threadedly arranged on the externally threaded portion of the 
screw 3 and has an upwardly projecting pin 5a thereon. An approximately 
U-shaped or hairpin shaped spring member 6 is attached to the pin 5a. The 
two legs 6a, 6b of the spring member 6 extend parallel with respect to the 
upper surface of the ski 1 and are supported on the bottom sides thereof 
by a cross brace 7 extending laterally across the housing 2 and being 
fastened to the opposide sidewalls thereof. In addition, the other side or 
top of the legs are engaged by a stop 8 to effectively hold them in a 
centered position, which stop is secured on the housing 2. The stop 8 is 
received between the legs of the spring 6. By rotating the screw 3 it is 
possible to adjust the lengthwise position of the spring member 6 relative 
to the housing 2. The stop 8 remains stationary and the legs of the spring 
6 move therepast. 
A sliding member 9 extends through a hole in the upper side 2c of the 
housing 2 and between the legs 6a, 6b of the spring member 6, an enlarged 
head 9a at the lower end of the sliding member being located below the two 
legs 6a, 6b. The spring member 6 is manufactured of a low friction 
material or, if desired, spring steel coated with plastic. The downwardly 
facing surfaces of the two legs 6a, 6b are inclined converging upwardly 
and serve as a bearing surface for the upwardly inclined surfaces 9b on 
the enlarged head 9a of the sliding member 9. The upper end of the sliding 
member 9 projects beyond the upper surface 2c of the housing 2, is 
threadedly secured in a hole in a sole plate 10. There is provided between 
the sole plate 10 and the upper side 2c of the housing 2 two plate-shaped 
control members 11a, 11b, one stacked on the other, and which function as 
two-arm levers (see FIG. 3). Each control member is pivotal about a common 
and centrally positioned, vertically upright pin 12 secured to the upper 
side 2c of the housing 2. The upper end of the pin 12 has a spherical 
bearing member 12c thereon receiving the sole plate 10 therethrough. Thus, 
the sole plate can, due to the bearing 12c, pivot about both vertical and 
horizontal axes. Also combined movements of the sole plate 10 about the 
aforementioned axes are possible. The two control members support, in the 
region of their ends closest to the tail end of the ski, two downwardly 
extending bent sections 12a , 12b, each of which is guided in arc-shaped 
recesses 2e, 2f in the upper side 2c of the housing. The bent sections 12a 
and 12b bear or rest on the laterally outwardly facing side surfaces of 
the legs 6a, 6b of the spring member 6. Link members 13a, 13b are hingedly 
interconnected by a hinge pin 14 and to the control members 11a, 11b. The 
hinge pin 14 is guided in a longitudinally extending slotted hole 2d in 
the upper side 2c of the housing 2 and in a correspondingly shaped slot 
15a in a shoulder 15 thereon. This assures that during a deflection of 
only one of the two legs 6a, 6b, the other leg will carry out a mirror 
image movement in the opposite direction. 
The portion of the hinge pin 14 has in the region which is provided 
immediately above the two link mmebers 13a, 13b an enlarged cylindrical or 
square area, through which a bolt 22 extends, the ends of which project 
laterally outwardly therefrom. The shoulder 15 of the housing 2 supports 
an upwardly extending block arrangement thereon on which a two-arm release 
lever 23 is pivotally supported for movement about an axle 23a. The 
uppermost arm of the release lever 23 is to operatively cooperate with the 
tip of the ski pole or the hand of the skier. The lower arm of the release 
lever 23 is constructed fork-shaped, and the two fork prongs rest on the 
ends of the bolt 22. 
The sole plate 10 has on its end adjacent to the tip of the ski, and on 
both lateral sides thereof a pair of upwardly extending bearing blocks 
10a, 10b, longitudinally spaced thereon, and which support a swivel axle 
16 therebetween. Each swivel axle extends through a slotted hole 17a in an 
angular clamping jaw 17, the upper lever arm 17b of which, in the skiing 
position, rests on a support surface of the ski shoe 18. The lower lever 
arm 17c has two recesses 17d and 17e therein, of which the one recess 17e 
is associated with a projection on the sole plate 10. A control plate 19 
is guided for movement in the vertical direction between each pair of 
bearing blocks. The control plate has, on approximately the lower half 
thereof, a groove 19a therein which is open toward the vertical 
longitudinal center plane of the ski and is approximately trapezoidally 
shaped in cross section. Projections 20 on the associated control member 
11a or 11b are received in the groove 19a when in the skiing position. The 
control plates 19 are under the influence of springs, which are not 
illustrated in the drawings, which urge the control plates continually 
upwardly. 
Before the ski binding is put into use, the releasing moment, for example 
during a frontal fall, must first be adjusted. The nut 5 is, for this 
purpose, adjusted in the longitudinal direction of the ski by means of the 
screw 3. This causes, however, the spring member 6 to also be moved, so 
that the sliding member 9 now engages the leg 6a, 6b of the spring member 
at a different point. The effective lever arm of each of the two legs 6a, 
6b is therefore adjusted to correspond to the physical attributes and the 
skiing capability of the user. 
The two clamping jaws 17 are, in the stepping-in position of the ski 
binding, in the position which is illustrated in FIG. 5. They are held in 
this position because the upper ends of the control plates 19 are urged 
against the outer side of the angular clamping jaws 17 by springs (not 
illustrated). If now the ski shoe 18 is introduced through a movement in 
vertical direction between the clamping jaws 17, then the two control 
plates 19 are first moved downwardly against the force of the not 
illustrated springs, and thereafter the upper ends of the control plates 
are received in the recesses 17d of the clamping jaws 17. Due to the 
slotted holes 17a two clamping jaws 17 slide downwardly, whereby they are 
held between the sole plate 10, which engages the recesses 17e, and the 
control plates 19, which engage the recesses 17d. The two projections 20 
on the control members 11a, 11b are at the same time urged into the 
grooves 19a of the control plates 19 under the influence of an expanding 
spring 21. This assures that the ski shoe 19 will be clamped tightly, and 
that the sliding member 9 will be in the position illustrated in FIG. 6. 
If a frontal fall of the skier occurs during skiing, then the sliding 
member 9 moves into the position illustrated in FIG. 7, in which the two 
legs 6a, 6b of the spring member 6 are already urged to the outside. The 
legs 6a, 6b, however, have effected during their outward movement an 
outward movement of the two control members 11a and 11b, which causes the 
projections 20 on the control members to be pulled out of the grooves 19a 
in the control plates 19. Now the clamping jaws 17 can be swung to enable 
the ski shoe 18 to leave the ski binding. 
If, however, the skier undergoes during skiing a twisting fall, then the 
condition illustrated in FIG. 8 occurs. That is, the sliding member 9 is 
thereby moved laterally toward the side and carries along with its 
enlarged head 9a one leg 6a of the spring member 6. The other leg 6b of 
the spring member 6 remains in the rest position, whereat its inner side 
surface rests on the stop 8 on the upper side 2c of the housing 2. The two 
control members 11a, 11b behave differently, however. They are, as has 
already been described, connected with one another through the link 
members 13a and 13b and through the hinge pin 14. Thus, if one control 
member, for example the control member 11a, is swung then this results 
automatically in an analogue swinging of the other control member 11b in 
the opposite direction. However, this assures, in the case of a twisting 
fall and during which only one of the two legs 6a or 6b of the spring 
member is swung, that the projections 20 are pulled out of the grooves 19a 
of the control plates 19 on both sides of the longitudinal center plane of 
the ski to effect an opening of the clamping jaws 17. 
Of course, the releasing moment is substantially smaller during a twisting 
fall than during a frontal fall. This, on the one hand, is due to the fact 
that during a twisting fall only one of the two legs 6a, 6b of the spring 
member 6 are swung and, on the other hand, is due to the fact that during 
a twisting fall the full force is transmitted onto the leg, whereas during 
a frontal fall only the horizontal components of the force, which in the 
normal plane acts onto the upper side of the ski, is utilized for swinging 
the two legs 6a, 6b of the spring member 6, which components operate 
through the two inclined surfaces 9b on the head 9a of the sliding member 
9. 
In order to voluntarily open the inventive release binding, the release 
lever 23 is swung clockwise for example with the tip of the ski pole. This 
causes the hinge pin 14 to be moved in the slotted hole 2d in the upper 
side 2c of the housing and in the slot 15a in the shoulder 15 of the 
housing 2 in a direction toward the tip of the ski. This results in a 
swinging apart of the link members 13a and 13b and of the control members 
11a and 11b. This causes, however, the projections 20 of the control 
members 11a and 11b to be pulled out of the grooves 19a in the control 
plates 19 so that the clamping jaws 17 can be swung outwardly and the ski 
shoe 18 can leave the ski binding. 
FIG. 9 illustrates one embodiment which can be opened also during a fall 
backward. The enlarged head 9'a of the sliding member 9' has for this 
purpose, and on both sides thereof, a laterally outwardly facing groove 
9'c, which in cross section is wedge-shaped and which is defined on one 
side by an inclined surface 9'b. In the engaged or skiing position, the 
correspondingly formed legs 6'a, 6'b of a spring member 6' are received 
therein. Bent sections 12a and 12b of the control members 11a, 11b again 
rest on the outer sides of the leg 6'a and 6'b. 
The operation of this ski binding corresponds during frontal and twisting 
falls with the operation of the first discussed embodiment. However, if a 
fall to the rear takes place, then the downwardly facing wedge surfaces on 
the head 9'a of the sliding member 9' starts to function. The downwardly 
facing wedge surfaces effect a moving of the ends of the two legs 6'a, 6'b 
of the spring member 6' laterally outwardly away from the longitudinal 
center plane of the ski which, as stated above, results in an opening of 
the clamping jaws 17 and thus effects a release of the ski shoe 18. 
Of course the invention is by no means to be limited to the exemplary 
embodiments which are illustrated in the drawings and which are described 
above. Rather, various modifications of the same are possible without 
departing from the scope of the invention. For example, it would also be 
possible to provide in place of a pressure spring, which urges the arms of 
the control members to the outside and are adjacent to the clamping jaws, 
a torsion spring serving the same purpose. Furthermore, it is not 
absolutely necessary to support the sole plate in a toggle joint on the 
ski-fixed housing. Rather, embodiments are also possible, in which the 
vertical and the horizontal swivel axis are offset with respect to one 
another in the longitudinal direction of the ski-fixed housing.