Land vehicles – Skates – Runner type
Patent
1980-11-24
1983-05-17
Mitchell, David M.
Land vehicles
Skates
Runner type
A63C 710
Patent
active
043836992
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates in general to ski brakes and notably to ski brakes of the type comprising brake shoes which, when retracted to their inoperative position, are flush with the ski side edges.
DESCRIPTION OF THE PRIOR ART
The most popular ski brakes comprise a pair of pivoting brake arms disposed on either side of the ski and pivotally mounted thereon about a transverse axis. At one end, these two arms are interconnected by a cross member acting as a control pedal, and a return spring constantly urges the two arms to their operative position in which their ends opposite said one end are lowered in relation to the ski bottom surface so as to penetrate into the underlying snow layer. Ski brakes of this character are made as a rule from metal wire and the transverse pivot axis may consist in this case of a pair of elbows formed in the two pivoting brake arms, respectively.
When the ski boot is positioned on the ski it exerts a pressure on the control pedal, thus holding the operative portions of the brake arms in their raised, retracted position. However, the operative portions of these arms project laterally beyond the side edges of the ski, and this may constitute a serious drawback under certain circumstances.
Therefore, certain known ski brakes are so designed that the operative portions of their pivoting arms are moved towards each other above the ski top when they are raised to their retracted position. Various systems have been proposed for retracting the pivoting brake arms to this recessed position.
Thus, in French patent application No. 75 07899, published under No. 2,272,695, the brake arms are retracted by tensioning the metal wire constituting said arms, and by providing tension means in the form of a knee-action or over-center device adapted to be flattened by the boot pressure. However, the operation of this known system is not fully reliable for a relatively great force must be exerted to alter the shape of the metal wire constituting the brake arms. In fact, this wire must on the other hand have a rigidity sufficient to exert an efficient braking action and prevent the brake arms from being distorted when simple shocks are exerted thereon.
In another French patent application, No. 76 11752 published under No. 2,308,389, the brake arms are retracted to their raised position by exerting a pressure on a deformable plate or hinged quadrilateral disposed beneath the boot location so as to be flattened by the ski boot when the latter is fitted in position. The arrangement is such that the flattening of the plate or hinged quadrilateral is attended by the movement of the two brake arms toward each other after said arms have been raised to their retracted position.
However, if the control plate consists of a curved blade, the latter will exert a relatively strong pressure against the boot sole. This is likely to interfere with the boot release conditions when the safety ski binding associated with this boot is actuated, for example in case of a skier's fall. Besides, if the control plate consists of a hinged quadrilateral, the system contemplated is particularly complicated an expensive. Moreover, this system appears to be scarcely reliable inasmuch as its operation is likely to be impaired in case of icing.
In a further French patent application, No. 75 34137 published under No. 2,330,419, the brake arms are retracted by the action of one or a plurality of cam faces possibly carried by an auxiliary pedal. But in this case the solutions contemplated are not fully satisfactory. In fact, since the pivot brake arm retraction is obtained by elastic deformation of the metal wire constituting said arms, a relatively great effort must be exerted thereon for this purpose. Moreover, this system also produces parasitic stress interfering with the ski boot release conditions in case of actuation of the safety ski binding.
On the other hand, to avoid excessive over-all dimensions, the height of the control cam faces or ramps must be kept within reasonable limits, thus l
REFERENCES:
patent: 3989271 (1976-11-01), Riedel
patent: 4101145 (1978-07-01), Korger
patent: 4123083 (1978-10-01), Riedel
patent: 4124223 (1978-11-01), Kubelka
patent: 4194758 (1980-03-01), Svoboda et al.
patent: 4234206 (1980-11-01), Hofbauer et al.
patent: 4294458 (1981-10-01), Sedlmayr
Bierman Jordan B.
Bierman Linda
Mitchell David M.
Smith Milton L.
STE Look
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