Ski binding incorporating both electronic and mechanical release systems

A ski binding release mechanism that includes both an electronic and a mechanical release mechanism. The mechanical release mechanism incorporates a delay feature that allows it to function only if the electronic mechanism experiences a failure. The delay feature is provided by a cylinder movable with respect to a stationary piston positioned therein, the piston dividing the cylinder into two chambers. Movement of the cylinder, required to release the soleholder of a ski boot, is retarded by the time required to pass liquid in the cylinder from a first of the chambers to a second of the chambers through a choke passage in the piston as the cylinder moves. Movement of the cylinder is caused by a plunger connected to the soleholder of the ski binding that urges against the cylinder under the influence of a sustained, predetermined, potentially hazardous force acting on the binding. A spring may be located within the cylinder to absorb intermittent forces imposed on the cylinder not strong enough to pose a hazard. Resetting of the device may be accelerated through provision of a check valve in the piston that allows the fluid to move back into the second chamber through the valve, as well as through the choke passage.

TECHNICAL FIELD 
This invention relates to safety ski binding release systems. More 
particularly, this invention relates to the provision of redundant 
mechanical release mechanisms that operate to release a skier's boot from 
a ski binding when the primary electronic release mechanism fails to 
operate. Specifically, this invention relates to compound safety ski 
bindings that include both mechanical and electronic release mechanisms, 
and in which the mechanical mechanism includes a delay feature that allows 
the electronic mechanism to assume release priority, but which becomes 
operative in the event that the electronic mechanism fails to operate. 
BACKGROUND OF THE INVENTION 
Safety ski bindings have long been a feature of quality ski equipment since 
they function to release a skier's boot when forces dangerous to the skier 
are applied thereto. Such forces are commonly experienced, for example, in 
the case of a fall where the leverage of an attached ski could cause the 
skier's lower limbs to experience potentially damaging forces. Release of 
the boot from the binding in such instances minimizes the forces 
experienced during the fall, thus helping to prevent injuries, including 
bone trauma to the skier's ankles and legs. 
In the past, bindings have typically featured mechanical release 
mechanisms; however, considerable effort has been devoted to the 
development of release bindings that rely upon electronic circuitry since 
bindings incorporating such circuitry offer the possibility of more 
precise and consistent response to whatever threshold release force is 
selected to activate the binding release. 
One form of such electronic binding comprises electronic circuitry that 
includes at least one transducer positioned to detect forces acting on the 
bindings in a particular direction. The transducers produce a 
release-triggering current when subjected to a threshold force value, 
resulting in operation of the mechanism and release of the skier's boot. 
The current, for example, is operative to energize or de-energize an 
electromagnet, depending upon the circuitry, the components of the 
mechanism then acting to produce the desired release. 
While electronic bindings have much to commend them, they have the 
disadvantage of being susceptible to inoperativeness caused by the 
occasional failure of a component in the circuit, the electromagnet, or in 
the battery energizing it. Such failures are sometimes difficult to detect 
beforehand, and so can result in failure of the binding to release when 
necessary with the injurious consequences which that can entail. 
In view of the potential advantages that electronic bindings offer, a 
number of efforts have been made to overcome the drawbacks described, and 
remedial designs have been utilized to compensate for such drawbacks. 
German Patent No. 2,737,535 A-1, for instance, employs shear pins to 
support the sole holder portion of the binding. When the binding is 
subjected to unacceptable stresses, the shear pins fail, releasing the 
sole holder and freeing the boot from the ski binding. Unfortunately, the 
holder thus released must be re-attached to the ski, an operation not 
readily performed on a ski slope. Consequently, the necessity of 
reattachment can seriously interrupt skiing activity for the day on which 
the accident occurs, interfering with the pleasure of skiing. 
Another approach to the problem is that envisioned by German Patent No. 
2,938,756 A-1 which employs an electronic logic system that depends upon 
electronic monitoring of the release system'state of operativeness. The 
device incorporates switching means that shifts the release function from 
one activated by electronics to a mechanical release system when a fault 
develops. The drawback of such an approach, however, is that additional 
circuitry is required, an expedient that is both expensive and also 
vulnerable to malfunctioning. 
German Patent No. 3,017,841 C-2 provides dual release functionality 
including both mechanical and electronic release mechanisms. In this 
device also, however, it is necessary that an error be detected and a 
signal generated for subsequent transmission to an operating mode switch 
capable of changing the release system from an electronic to a mechanical 
release mode. 
BRIEF DESCRIPTION OF THE INVENTION 
In view of the foregoing, therefore, it is a first aspect of this invention 
to provide a ski binding with dual binding release functionality. 
A second aspect of this invention is to provide a ski binding having dual 
binding release functionality that requires no detection means to discern 
failure of the primary release system, nor the generation of a switching 
command to change to the secondary, back-up release system. 
Another aspect of this invention is to provide a ski binding having an 
electronic binding release function, and a mechanical binding release 
function in which the mechanical function is continuously operable, 
activating automatically in the event of failure of the electronic system. 
A further aspect of this invention is to provide a ski binding having an 
electronic binding release function, and a mechanical binding release 
function in which the functioning of the latter is delayed until the 
former has had an opportunity to operate. 
An additional aspect of this invention is to provide a ski binding having 
an electronic binding release mechanism, and a mechanical binding release 
mechanism in which the latter mechanism has force-dampening means 
associated therewith so that the mechanism will not activate in the 
absence of a substantially sustained force of a release threshold 
magnitude acting thereon. 
Still another aspect of this invention is to provide an electronic ski 
binding release system with a redundant mechanical binding release 
mechanism that provides continuing release capability despite the 
incapacity of the electronic release system. 
Yet a further aspect of this invention is to provide a ski binding with 
dual binding release functionality that includes a mechanical binding 
release mechanism that has rapid reset capability. 
The preceding and other aspects of the invention are provided by a ski 
binding release mechanism for a ski having dual release functionality 
comprising: electronic binding release means, and mechanical binding 
release means, said electronic means and said mechanical means both being 
adapted to unlatch the bootsole latch of a ski binding incorporating said 
mechanism when the binding is subjected to a predetermined threshold force 
in a selected direction, wherein said mechanical release means includes a 
mechanical delay means providing sufficient time for said electronic 
release means to function before said mechanical release means can 
function, so that if said electronic release means fails to function, said 
mechanical release means functions. 
The preceding and further aspects of the invention are provided by a ski 
having a ski binding release mechanism according to the preceding 
paragraph. 
The preceding and additional aspects of the invention are provided by a ski 
binding release mechanism for a ski having dual release functionality 
including both electronic and mechanical binding release means, wherein 
said electronic binding release means comprises: transducer means; an 
electromagnet; and a pivotal armature, said pivotal armature being 
associated with, and adjacent to said electromagnet and urged by spring 
means to pivot from said electromagnet in the absence of an operative 
magnetic force emanating therefrom thereby unlatching bootsole latching 
means, said electromagnet permitting and preventing pivoting of said 
pivotal armature depending upon whether said electromagnet receives an 
electrical impulse generated when said transducer means is subjected to a 
predetermined threshold force acting in a selected direction on a ski 
binding provided with said mechanism, and wherein said mechanical binding 
release means includes a delay feature that permits said electronic 
binding release means to operate before said mechanical binding release 
means becomes operational, said mechanical release means comprising: a 
movable, elongate cylinder; a cylinder piston; cylinder fluid; a plunger; 
spring means; and bootsole latch engaging means, said bootsole latch 
engaging means being connected to said cylinder, and said piston being 
located within said cylinder and fixable in position relative to a ski 
associated with said mechanism by a hollow rod extending at right angles 
from the center of said piston through a first end of said cylinder, one 
end of said plunger being connectable to the ski bootsole holder of a ski 
binding, and the other end extending through both ends of said cylinder 
and through said piston and said hollow rod, said plunger including first 
and second flanges as a part thereof, said first flange being located at 
the unconnectable end of said plunger, outside and adjacent said second 
end of said cylinder, and said second flange being located between said 
second end and said piston, while said spring means is located between 
said second end and said second flange, wherein the space between the said 
piston and said first end of said cylinder defines a first chamber, and 
the space between said piston and said second end of said cylinder defines 
a second chamber, both chambers being adapted to hold said fluid therein, 
and said piston being provided with a choke passage therethrough, whereby 
when said ski binding is subjected to said threshold force and said 
electronic binding release means fails to operate, said plunger is urged 
toward said second end, said force being initially restrained by the 
resistance of said spring means against said second flange, and the 
movement of said cylinder toward its second end caused by the force of 
said spring against said second end being delayed by the time required to 
displace said liquid from said first chamber to said second chamber 
through said choke passage, whereby further, when said threshold force 
becomes inoperative, said first flange is caused to urge against said 
second end, moving said cylinder back towards its first end, said movement 
transferring liquid from said second chamber to said first chamber through 
said passageway, resulting in resetting of the mechanism. 
The preceding and still other aspects of the invention are provided by a 
ski having a ski binding release mechanism according to the preceding 
paragraph. 
A preceding and still other aspects of the invention are provided by a 
mechanical ski binding release mechanism for a ski binding comprising: a 
movable, elongate cylinder; a cylinder piston; cylinder fluid; a plunger; 
spring means; and bootsole latch engaging means, said bootsole latch 
engaging means being connected to said cylinder and said piston being 
located within said cylinder and fixable in position relative to a ski 
associated with said mechanism by a hollow rod extending at right angles 
from the center of said piston through a first end of said cylinder, one 
end of said plunger being connectable to the ski bootsole holder of a ski 
binding, and the other end extending through both ends of said cylinder 
and through said piston and said hollow rod, said plunger including first 
and second flanges, said first flange being located at the unconnected end 
of said plunger, outside and adjacent said second end of said cylinder, 
and said second flange being located between said second end and said 
piston, while said spring means is located between said second end and 
said second flange, wherein the space between said piston and said first 
end of said cylinder defines a first chamber, and the space between said 
piston and said second end of said cylinder defines a second chamber, both 
chambers being adapted to hold said fluid therein, said piston being 
provided with a choke passage therethrough and a check valve therein, said 
check valve only allowing said fluid to pass from said second chamber to 
said first chamber, whereby when said ski binding is subjected to a 
threshold force, said plunger is urged toward said second end, said force 
being initially restrained by the resistance of said spring means against 
said second flange, and the movement of said cylinder toward its second 
end caused by the force of said spring means against said second end being 
delayed by the time required to displace said liquid from said first 
chamber to said second chamber through said choke passage, whereby 
further, when said force becomes inoperative, said first flange is caused 
to urge against said second end, moving said cylinder back toward its 
first end, said movement transferring liquid from said second chamber to 
said first chamber through said check valve, as well as through said 
passage way, resulting in rapid resetting of the mechanism. 
The preceding and yet further aspects of the invention are provided by a 
ski having a ski binding release mechanism according to the preceding 
paragraph.

DETAILED DESCRIPTION OF THE INVENTION 
The FIGURE shows a semi-schematic, partial view of a compound ski boot 
release mechanism that includes an electronic release component, a 
mechanical release component, and a ski bootsole holder. As shown, the 
electronic portion of the release mechanism comprises an electromagnet 1 
connected to a base plate 5, and having an armature 2 pivotally positioned 
adjacent the top of the electromagnet. In the absence of 
armatureimmobilizing magnetic attraction from electromagnet 1, the 
armature 2 is urged by a pivot spring 6 connecting the armature to the 
base plate 5 to pivot in a counterclockwise direction. In so pivoting, 
armature 2, guided by abutment 7 extending from the top of the magnet, 
engages an end of bell crank 3 thus causing the crank to pivot about pivot 
pin 4, movement of the bell crank, or structure associated therewith, 
resulting in the release of the sole of a ski boot. The bell crank is 
urged in a clockwise direction by a spring, not shown, being held in the 
position illustrated, in the FIGURE, i.e., resting on abutment 7, until 
the force of said spring is overcome by the force of the armature acting 
upon it, as described. 
Also forming part of the electronic portion of the release mechanism, but 
not illustrated, is appropriate circuitry of the type well known in the 
art, including a battery and one or more transducers. 
Additionally shown in the FIGURE, is the mechanical portion of the binding 
release, generally 8, comprising an engaging member 9, provided with a 
cavity 22 therein, the engaging member being connected to a cylinder 13. 
Cylinder 13 is divided into a first cylinder chamber 14, and a second 
cylinder chamber 15 by a piston 11. Cylinder 13 is movable relative to 
piston 11, the latter being immovable relative to a base plate 10 by 
virtue of the attachment of a hollow piston rod 12 that connects the 
piston 11 to the base plate. As in the case of base plate 5, base plate 10 
is also attachable directly or indirectly to a ski binding connectable to 
a ski. 
As shown, piston 11 includes a choke passage 16 and a check valve 17. A 
plunger 18 includes a larger diameter portion attachable to the sole 
holder of a ski binding, to the right in the FIGURE, and a smaller 
diameter extension 20, to the left in the FIGURE, about which is disposed 
a dampening spring 24. As can be seen, plunger 18 extends through the 
hollow center of piston 11 and piston rod 12, and through both ends of 
cylinder 13, and is provided with a plunger extension flange 23 and a 
spring abutment flange 19. 
In performing its release function, the mechanism works in the following 
manner. In the absence of a potentially damaging force acting on the ski 
binding, the electromagnet 1, which preferably is of the remanent or 
permanent magnet type, retains the armature 2 in close association with 
the top thereof due to the magnetic force emanating from the magnet. When 
such a force is experienced, however, at least one transducer positioned 
in a location suited to detect the force produces an electronic signal 
that directly or indirectly, depending upon the circuitry involved, acts 
to disable the magnetic force holding the armature adjacent to the 
electromagnet. With the magnetic force thus inoperative, pivot spring 6 
causes the armature to pivot upwards, engaging the end of the bell crank 
3, in turn forcing the latter to pivot in a counterclockwise direction in 
the FIGURE against a spring which would otherwise hold it in place on 
abutment 7. Pivoting of the bell crank 3 either directly or indirectly 
produces the unlatching of a soleholder, not shown, holding the ski boot 
in the binding. 
In the event of a malfunction, as for example in the event of a circuit 
failure, loss of power from the battery, or because of some other reason 
the electronic release mechanism should fail to function, release of the 
binding is procured through the action of the mechanical release system as 
follows. 
The same force that would otherwise produce release of the ski boot by the 
electronic release mechanism also acts upon the mechanical release system 
8 by virtue of the attachment, either directly or indirectly, of plunger 
18 to the soleholder of the ski binding. Such force is transmitted by the 
plunger and its attached spring abutment flange 19 to dampening spring 24. 
Temporary forces experienced of the type insufficient to cause damage to 
the skier's limbs are transmitted by the spring abutment flange to the 
dampening spring, the plunger extension flange 23 being free to move 
within the bootsole latch engaging member cavity 22 in response to 
intermittent, short-term compression of the spring. Although the spring 24 
bears against the cylinder end wall 21 as the mechanism is subjected to 
such intermittent forces, cylinder 13 is restrained from precipitant 
movement that might otherwise prematurely result in release of the ski 
boot by a delay mechanism described in the following. 
As can be seen from the FIGURE, cylinder 13 is divided by piston 11 into a 
first cylinder chamber 14, and a second cylinder chamber 15, both of which 
are adapted to contain a cylinder fluid, not shown. Consequently, before 
cylinder 13 can move relative to the piston 11, to the left in the FIGURE, 
the fluid in the first cylinder chamber must be transferred to the second 
cylinder chamber. Such transfer is accomplished through a choke passage 16 
that retards passage of the fluid due to its limited cross-sectional area, 
which may be varied, long enough to allow the electronic release to 
operate, but not so long as to allow the force to result in injury to the 
skier. When the mechanism is subjected to intermittent forces of 
relatively short duration, such delay is sufficient to prevent movement of 
the cylinder far enough so that the bootsole latch engaging member 9 
engages the end of bell crank 3 or some other structural feature, for 
example armature 2, to trigger a release. When, however, such force is 
substantially sustained, sufficient of the cylinder liquid is transferred 
to accommodate movement of the cylinder to a bell crank-engaging release 
position. 
The delay thus provided is long enough so that the electronic release 
mechanism has a prior opportunity to release the soleholder before the 
mechanical system becomes operative, assuring operation of the mechanical 
system only as a back-up release for the ski boot held in the binding. 
While the mechanical release system could function without the presence of 
a dampening spring 24, its use is preferred since it helps to absorb minor 
and intermittent forces as previously described. 
Piston 11 may also include a check valve passageway 17 that is designed to 
block the transfer of fluid from the first cylinder chamber to the second 
cylinder chamber, but to allow flow in the opposite direction. Although 
not required, its use is preferred since after the force on the binding 
has become inoperative, plunger 18 re-establishes its original position, 
moving to the right in the FIGURE either as a result of urging from a 
special spring provided for the purpose, not shown, or as a consequence of 
the return motion of the binding, and urging cylinder 13 to move in the 
same direction as a result of the contact of plunger extension flange 23 
against the cylinder end wall 21, re-establishing the cylinder's initial, 
normal position. When the cylinder 13 moves to the right, cylinder fluid 
is transferred through check valve 17, as well as choke passage 16 
allowing a more rapid resetting of the mechanism to its original state 
prior to action of the force then would otherwise be possible in the 
absence of the check valve. 
The advantage of the compound release systems is that the mechanical system 
is independent of the electronic system and is always ready to operate 
under the influence of a potentially dangerous force acting on the 
binding. The mechanical system does not require "cocking", or a 
switch-over operation. Thus, while the consistency and accuracy of an 
electronic release system is retained in the absence of malfunctioning, in 
the event of disability of the electronic system, the mechanical system is 
fully and reliably operable. 
While in accordance with the patent statutes, a preferred embodiment and 
best mode has been presented, the scope of the invention is not limited 
thereto, but rather is measured by the scope of the attached claims.