The present invention relates to a ski boot closure device.
Several devices for ski boots are currently known which allow for example to close the quarters and lock one or more pressers arranged inside the shell.
A U.S. Pat. No. 4,571,855, is known, for example, to disclose a lever for the closure of the quarters which uses two cables and has a system for the differentiated tensioning thereof.
This differentiation is intrinsically necessary, since when the quarters are opened the working length of the cables must be different, and this has made necessary to provide a guide member for said cables above said lever at the rear quarter.
This undoubtedly produces a disadvantage, because too much space is taken up on the rear quarter and, besides the undesirable aesthetic aspect, no other devices can be placed at the rear quarter.
A French patent, No. 84.16966 filed on Oct. 30, 1984, is also known which describes a rear-entry ski boot comprising a lever provided with two coaxial winders for two separate cables.
A first cable closes the quarters and the other cable operates a foot instep presser.
Said two separate cables can be actuated by means of a single knob, and means are provided in said knob adapted to provide different transmission ratios; the different transmission ratios are required both to obtain the different take-up of the cables and to balance the efforts for the tightening thereof.
Said known device, however, is relatively complicated structurally, because it requires a different degree of take-up of the cables for an equal number of turns imparted to the single knob.
Closure and adjustment devices are also known which are constituted by traction elements associated with a vertical lever so that an increase in the tension of said traction elements is followed by a shift of the point of application of the resisting force, and thus the effort on the lever is variable.
Other known devices comprise a vertical lever associated for example with the rear quarter of the boot and sliders axially movable on a threaded stem associated with a lever for the take-up of the cables. When the lever is closed, the slider and stem are subjected to a moment that, after some time, eventually leads to the stripping of the thread of the threaded stem or of the complementary thread of the sliders.