Closure device particularly for ski boots

This invention relates to a closure device particularly for ski boots of the kind defined in the pre-characterising clause of claim 1.

It is a well known fact that the closure or latching devices currently mounted on ski boots generally comprise a number of hooks, which may have a variety of configurations and operate in practice on the lever principle.

This type of closure, even though universally accepted, is in many cases difficult to use by the skier, especially in the light of the environment wherein such hooks or latches are to be operated, and moreover, fails to provide a quick, easy and accurate adjustment capability of the clamping force which it is desired to apply.

According to other approaches, the closure is effected by actuating a Maltese cross mechanism, which has, however, the disadvantage of a rather high pitch, which results in the impossibility of achieving a fine adjustment of the closure.

Another drawback to be attributed to this type of mechanism is that it has been ascertained experimentally that vibrations or other incidental factors tend to release the closure, so that the latter is actually unreliable. DE-C-365 414 discloses a closure device of the kind defined in the pre-characterising clause of claim 1, in which, however, a separate push button is provided for releasing the device. The user is therefore compelled to exert spontaneous actions for operating the device.

Thus the task of the invention is that of eliminating such prior drawbacks by providing a closure device, specially designed for use on ski boots, which in addition to affording the possibility of achieving the closed or latched state in a quick manner, also enables a very accurate adjustment of the closing effort to be exerted.

Within this task it is an object of the invention to provide a device which can be easily operated even with gloves on one's hands, without requiring any special effort by the user.

A further object of the invention is to provide a device, which while being perfectly lockable in any desired position, is also readily releasable when the closure device is to be opened.

Yet another object of the invention is to provide a closure device which is highly reliable in use, and which can ensure the utmost accuracy in operation.

The invention is defined by the characterising clauses of claim 1.

The features and advantages of the invention will be more clearly understood from the following description of a preferred, but not limitative, embodiment of a closure device particularly for ski boots, with reference to the accompanying illustrative drawings, given herein by way of example only, and where: <ul id="ul0001" list-style="none"><li>Figure 1 is an exploded perspective view of the device in diagrammatic form;</li><li>Figure 2 shows, in elevation and plan view respectively, a ring nut arranged to cooperate with ratchet gear means;</li><li>Figure 3 is a cross-sectional view of this device;</li><li>Figure 4 is a schematical sectional view taken along the line IV-IV of Figure 3;</li><li>Figure 5 shows schematically a sectional view taken along the line V-V of Figure 3; and</li><li>Figure 6 is a diagram showing a possible application of this closure device to the cuff portion of a boot.</li></ul>

With reference to the drawing figures, the closure device particularly for ski boots, according to the invention, comprises a box-like body, which includes a lower half-shell 1, associable with one of the flaps to be brought together, and an upper half-shell 2, adapted for engagement with the lower half-shell 1 and attachable by means of screws or similar fastening means.

The box-like body as outlined above defines on its interior a cylindrical cavity 3, wherein a spool 4 is accommodated rotatably, said spool having a pivot pin 5 which is carried at its ends in holes 6, respectively defined in the lower half-shell 1 and upper half-shell 2.

On said spool 4, there is defined a groove 7 for winding a pair of small cable lengths 8 thereon, which have their ends associated with diametrically located points on the spool 4.

More specifically, each small cable length 8 is provided at one end with an enlarged portion 9 adapted for insertion into seats 10 defined on the spool to thus secure the cable end.

The other ends of the small cables 8 are provided, in this embodiment of the invention, with an enlarged body 11 which can be inserted into an engagement seat 12 defined by the half- shells 1 and 2, thereby the small cable lengths have in practice a closed loop configuration.

The cables are run through the interior of a tubular elbow 15 which is associated with, or in any way secured to, the other of the boot flaps to be brought together, so that, by winding the cable 8 onto the spool 4, the tubular elbows 15 are brought together to produce the closure sought.

The provision of two small cable lengths 8 in a closed loop configuration is only dictated by manufacturing convenience considerations, since it would also be possible in theory to utilize but one cable to bring the flaps together, and to secure, for example, the ends of the cable respectively to the spool and to the other flap to be united without requiring the provision of the cable deflecting tubular elbows.

The spool 4 is formed, at the upper portion thereof, with a recess 20 having on its periphery an inside serration 21 in mesh engagement with a small pinion gear 22, which can be rotated through a knob 30 located externally to the cited box-like body.

More specifically, the pinion 22 has at its upper end a bevelled cylindrical shank 23 which can be inserted into a shaped hole 24 correspondingly defined on the interior of a ring nut 25.

The ring nut 25 has a body 31, defining internally said hole 24, which is provided with a long pitch external left-handed quick-thread formations 32 and, at its lower axial end, with a flange 33 having a serration 34 on its bottom face.

The knob 30 is connected to the ring nut 25, and more precisely engages said quick-thread formations 32. Also provided is a covering cap 40 having a projection 41 the configuration whereof matches the hole 24 and which can be inserted axially through the hole 24 to abut against the end of the shank 23; the cap 40 is secured by means of a screw 43 which engages in a female thread formation 44 defined axially in the shank 23. The cap 40 has a peripheral border 45 which is inserted into a ring-like seat 46 defined on the outer face of the knob 30.

The device further comprises ratchet gear means including a pawl 50 hinged to the upper half-shell 2 for oscillation about an axis extending in a perpendicular plane to the axis of the ring nut 25. The pawl 50 has at the top an engagement tooth 51 adapted for releasable engagement with the serration 34, thereby it behaves as a pawl element as the ring nut is rotated in one direction, and as a locking element as the ring nut is rotated in the opposite direction.

Said pawl 50 is urged from below by a spring 52 acting on the inner bottom of the half-shell 1 and has, on the same side as the tooth 51, a shoulder 53 adapted to engage by contact an actuation border 60 defined on the inner face of the knob 30.

The closure device as shown diagrammatically in Figure 6 can be mounted by attaching the box-like body to the rear portion 70 of the boot cuff and connecting the cables 8, and more specifically the tubular elbow 15, to the edges of the front portion 71 of the cuff.

To produce the closed state of the device, the knob 30 is turned clockwise. Through the coupling system just described, owing to the provision of the left-handed threads 32, the knob will first rotate relatively to the ring nut until it abuts against the cap 40. At this stage, the knob will become rigid with the ring nut 25, and with the pinion 22 which, by meshing with the inside serration 21, causes the spool 4 to rotate and wind around its ring-like groove 7 the cables 8, which results in the flaps being brought together. During this rotation step, the actuation border provided on the inner face of the knob 30 practically does not engage with the shoulder 53 of the pawl 50, so that the pawl is positioned with its tooth 51 elastically urged against the serration 34 and the ring nut is only allowed to rotate in the winding direction since the sloping flanks of the teeth 51 and serration 34 behaves in practice as a ratchet element. Rotation in the opposite direction is instead prevented in that the front portions of the teeth abut together, thereby the pawl 50 practically meshes with the serration 34.

As the clockwise rotation of the knob is continued, the desired clamping action of the closure device is achieved in a very accurate manner, thus providing a fine form of adjustment.

By turning the knob 30 in the opposite direction, that is counterclockwise, the knob, owing to the presence of the left-handed threads 32, practically threads itself onto the ring nut 25 and moves closer to the flange 33.

With this translation of the knob relatively to the ring nut, it occurs that the border 60 acts onto the shoulder 53, thus urging the pawl 50 against the bias of the spring 52 and disengaging the engagement tooth 51 from the serration 34.

As the pawl 50 is disengaged from the ring nut 25, the latter is enabled to freely rotate in a counterclockwise direction together with the knob 30 and spool 4 which is connected by the pinion 22 meshing with the inside serration 21, so that the cables will unwind from the groove 7 and enable the flaps to be moved away from each other in the opening direction.

In order to prevent, after the cables 8 have been fully unwound from the spool 4, the rotational movement from being continued such as to wind the cables in the opposite direction onto the spool, limiter means is provided in the form of an axially protruding tooth 80 in the serration 21, which will engage with a small collar 81 defined at the root of the teeth on the pinion 22 such as to inhibit rotation.

By contrast, to enable rotation in the cable winding direction, on the collar 81 there are provided cutouts, indicated at 82, so positioned as to enable the insertion of the protruding tooth during the cable winding step onto the spool.

The cutouts are provided with such a pitch as to be located at the protruding tooth after the spool has completed one revolution about its own axis in the clockwise direction only.

To enable an accurate positioning during the assembling operation, markings 90 are provided on the lower half-shell 1, both on the serration 21 and spool 22, which markings must be aligned together during the device assembling operation.

It should be further added that, on the lower half-shell 1, guiding troughs 95 are provided which enable the cable to be inserted onto the spool 4 in a practically tangent direction, so as not to create stress on the cable itself.

It will be appreciated from the foregoing that the invention fully achieves its objects, and in particular that the device allows the conversion of a rotary motion, as imparted to the knob 30, into a translatory motion of the cables 8. By way of illustration only, it is to be pointed out that with a prototype actually built it is possible to obtain a travel distance of about 160 mm for the cables, with a fine adjustment pitch of about 2 mm; that is, in practice, the mechanism can be locked automatically at any desired position, thus enabling an extremely fine adjustment capability.

Another advantage of the invention is that to operate the device, the user is only required to manipulate the knob 30, which having a considerable size, can be readily and easily manipulated by the user.

The invention as described in the foregoing is susceptible to many modifications and variations, without departing from the scope of the instant inventive concept.

Furthermore, all of the details may be replaced with other technically equivalent elements. In practicing the invention, the materials employed, as well as the dimensions and contingent shapes may be any suitable ones for the intended applications.