Fastening device, particularly for sports shoes

Abstract

 A fastening device, particularly for sports shoes including an engagement element (2), which is rigidly coupled to a first flap (3), and a traction element (4), which interacts with the engagement element, and a lever arm (10) that is freely transversely pivoted, at a first end, between the shoulders of a base (18) that is rigidly coupled to the second flap to be joined. In this device, the lever arm actuates the opening and closure operations when it is rotated in the same direction. This allows easier closure and opening operations, with a simplification of the opening-closure operating sequence, providing a lever arm that is free from stresses once closure has occurred.

Description

[0001] The present invention relates to a fastening device particularly for sports shoes and particularly for ski boots or skates.

[0002] Several kinds of lever used in ski boots are currently known. For example, Italian patent no. 1039897 discloses a lever constituted by an arm pivoted, at one end, by means of an appropriate pivot, to two shoulders that are rigidly coupled to a flap of the boot. The arm has a toothed region for interaction with the end of a hook that is associable, at the other end, with the other flap of the boot to be closed.

[0003] Said conventional lever requires surface finishing of good aesthetic quality, because the surface of the boot is obviously visible; accordingly, this requires the use of materials, such as aluminum or plastics, having a pleasant appearance for the skier but do not have high strength characteristics, which are necessary for the levers in order to withstand the stresses and impacts to which they are subjected during sports practice.

[0004] In any case, the protrusion of the levers with respect to the lateral surface of the boot does not give said boot a pleasant aesthetic appearance, and the levers are subject to accidental opening or to breakage in case of collision with the snow surface or with the slalom pole or with the other boot.

[0005] The lever is also subjected to loads once it is closed, and this increases the possibility of breakage.

[0006] As a partial solution to these drawbacks, Italian patent no. 1054289 discloses a closure unit for ski boots having a simplified structure, but also being difficult to close, owing to the limited grip surface for the hand, on which the force to achieve closure is then applied.

[0007] Italian patent no. 1,082,434 discloses a lever device for closing a ski boot and comprising a toothed band, rigidly coupled to a flap of the upper, and a lever rigidly coupled to the other flap of the upper. The lever is provided with an advancement ratchet that cooperates with the toothed band so as to close the boot.

[0008] This solution substantially allows to increase the degree of tension of the toothed band, maintaining the previously achieved degree of fastening, but at the same time has other drawbacks that are substantially due to its structural complexity and to difficulty in its actuation, since it is necessary to position the tip of the lever, designated by the reference numeral 7 and pivoted to the end of the lever designated by the reference numeral 6, at the gap between two adjacent teeth of the band so that jamming does not occur during the closure of the lever designated by the reference numeral 6. In order to solve this drawback, it is necessary to perform several movements with very small takeups.

[0009] The tip of the lever designated by the reference numeral 7 also has a central recess that forms two lateral tabs; only said tabs interact with the teeth of the underlying band, and this configuration, which is necessary to avoid interacting with the lever designated by the reference numeral 10, produces further drawbacks that are due to the possibility of a deformation of said tabs, with consequent impossibility to achieve closure adjustment.

[0010] In any case, the lever designated by the reference numeral 6 still protrudes vertically with respect to the band, and therefore to the flap of the upper; furthermore, the possible formation of ice or the accumulation of snow at the lever designated by the reference numeral 10 can lead, in case of accidental impacts, to the disengagement thereof with respect to the toothed band, thus causing the device to open.

[0011] Italian utility model no. 185645 discloses a lever-operated closure device, particularly for motorcycle boots, in which the arm of the lever, which is again pivoted at one end at an adapted support that is rigidly coupled to a flap, is inserted within adapted slits formed on another flap to be closed.

[0012] This solution has a small number of components but still has some drawbacks, such as the direct interaction of the lever arm with the flap to be closed, which may cause breakages or deformations due to the different strength of the materials that are in mutual contact.

[0013] FR-A-2432280 discloses a closure device composed of a U-shaped lever having wings pivoted at an adapted support that is rigidly coupled to a flap. A pivot is interposed between the wings and interacts with an adapted rack that is formed on, and protrudes from, the other flap to be joined.

[0014] This solution also has drawbacks, since the coupling between the lever arm and the rack is not always reliable, because the rack must be made of plastics, together with the flap of the boot, and must therefore be made of a material that does not withstand the intense stress applied during skiing.

[0015] Another solution uses a single lever arm that has a toothed region that interacts with an adapted pivot that is associated transversely to the wings of a U-shaped bar, which is pivoted about one edge, at one end, to the other flap to be joined.

[0016] This solution, too, therefore has the drawbacks mentioned above, with the addition of a closing operation that is difficult for the skier, who must practically turn the lever arm through 180^o.

[0017] As a partial solution to this drawback, German patent No. P 31 32 042.2 discloses a closure device, particularly for ski boots, in which there is a lever arm pivoted at one of the flaps to be closed. The end of a traction element is articulated to a median portion of the lever element, and the traction element is provided, at the opposite end, with a hook element that can be coupled in an engagement seat formed at the other flap to be fastened. The traction element has means for adjusting its working length and at least one substantially flexible portion.

[0018] Even this solution, however, constructively comprises a large number of components and protrudes beyond the contour of the boot; the closure device also has a considerable elongation on its longitudinal axis, which affects a very large area of the boot.

[0019] As a partial solution to these drawbacks, European patent No. 0 484 846 discloses a lever for sports shoes, particularly for fastening two flaps of a ski boot, comprising a lever arm that is fully or partially associated at at least one adapted seat that is formed on one of said flaps. A grip element for engagement means provided on the lever arm is associated with the other one of said flaps.

[0020] Although it is undoubtedly valid, this solution too has drawbacks, since the mutual connection between the lever arm and the seat formed on the flaps is not optimum; moreover, the need has been observed to modify the adjustment of the degree of tensioning that can be applied with the lever.

[0021] In the mentioned prior art, therefore, the various observed drawbacks include that of having levers that are subjected to loads, once fastening has occurred and therefore said lever has been closed, and of having levers that occupy considerable space, especially in a vertical direction, as well as of having levers that have non-optimum ergonomics in use.

[0022] The aim of the present invention is therefore to solve the described technical problems, eliminating the drawbacks described above in the prior art by providing a fastening device that is optimally associable with the flaps of a sports shoe, such as a boot or a skate, and has a simple operating sequence for activation and deactivation.

[0023] Within the scope of this aim, an object is to provide a device that reduces the load to be applied to the lever arm, particularly during release.

[0024] Another important object is to provide a device that despite comprising a lever arm that can be operated by the user, allows to protect said arm from stresses caused by the loads required to keep the flaps of the shoe fastened, and therefore to reduce the risk of possible breakages caused by the loads applied throughout the use of the boot on the feet.

[0025] Another object is to provide a device that allows to ensure optimum adjustment of the mutual fastening of the two flaps to be joined, while occupying a small vertical space with respect to the outer contour of the shoe.

[0026] Another object is to provide a device that allows to release the flaps rapidly and easily.

[0027] Another object is to provide a device that is not subject to accidental openings caused by pressures or impacts affecting it.

[0028] Another object is to provide a device that is reliable and safe in use.

[0029] This aim, these objects, and others which will become apparent hereinafter are achieved by a fastening device, particularly for sports shoes, comprising an engagement element rigidly coupled to a first flap and a traction element cooperating with said engagement element, said traction element being operatively connected to a lever arm that is freely transversely pivoted, at a first end, between the shoulders of a base, said base being rigidly coupled to a second flap, characterized in that said lever arm actuates the opening and closure operations of said device upon a rotation applied to it in the same direction.

[0030] Further characteristics and advantages of the invention will become apparent from the detailed description of two particular but not exclusive embodiments, illustrated only by way of non-limitative example in the accompanying drawings, wherein:

figure 1 is a partially sectional side view of the device, in the condition in which said device is closed and the lever arm is inactive;

figure 2 is a view, similar to the preceding one, of the arrangement of the lever arm when it is turned so as to place the device at the starting point of the stroke for mutually disengaging the traction element and the engagement element;

figure 3 is a view, similar to figure 2, of the position of the lever arm in which the release step begins;

figure 4 is a lateral perspective view of the condition of the preceding figure;

figure 5 is a view, similar to figure 3, of an intermediate release position;

figure 6 is a view, similar to figure 5, of the final release position;

figure 7 is a view, similar to figure 6, of the initial position of the lever arm to mutually engage the traction element and the engagement element;

figure 8 is a lateral perspective view of the device in the condition of figure 7, with the covering element omitted for the sake of clarity;

figure 9 is a view, similar to figure 7, of the position for maximum stress during engagement;

figure 10 is a view, similar to figure 9, of the final engagement position;

figure 11 is an exploded perspective view of the device;

figure 12 is a top view of the device;

figure 13 is a lateral perspective view of a further embodiment of the device in a condition similar to that of figure 1;

figure 14 is a view, similar to figure 13, of the device in the position for beginning the release step;

figure 15 is a view, similar to the preceding one, of the condition during the release of the device;

figure 16 is a view, similar to figure 13, of the device in the condition in which it is open, with the lever arm in the inactive condition;

figure 17 is a partially sectional view, taken along a longitudinal axis, of the device in the condition shown in figure 14;

figure 18 is a view, similar to figure 17, of the device in the condition shown in figure 15;

figure 19 is a view, similar to figure 15, of the step of the initial position of the lever arm to achieve mutual engagement of the traction element and of the engagement element;

figure 20 is a view, similar to figure 19, of the final step of the engagement that leads to the closure of the device;

figure 21 is a view, similar to figure 13, of the device in closed condition, with the lever arm inactive.

[0031] With reference to the above figures, the reference numeral 1 designates the fastening device, particularly usable for a sports shoe, such as for example a ski boot, a roller skate, or an ice skate.

[0032] Device 1 comprises an engagement element 2, such as a rack or one or more teeth, rigidly coupled to a first flap 3 of the shoe.

[0033] The fastening device is constituted also by a traction element 4 that is preferably constituted by a pawl. A first transverse pivot 5 is provided at one end of the pawl that is adjacent to the base, and interacts with engagement element 2. A connecting element 7 is associated with the other end of said traction element by means of a second pivot 6; in turn, connecting element 7 is associated, by means of an adapted third pivot 8, at the free ends of a traction element 9.

[0034] The fastening device 1 is constituted also by a lever arm 10 having, at a first end 11, two first wings 12a and 12b between which a first pair of holes 13a and 13b, a second pair of holes 14a and 14b, and a third pair of holes 15a and 15b are formed transversely and respectively starting from the free end.

[0035] The lever arm 10 is transversely pivoted freely, by means of a fourth pivot 16, between two first shoulders 17a and 17b that protrude from a base 18 that is rigidly coupled to the second flap 19 of the sports shoe. Fourth pivot 16 passes at the first pair of holes 13a and 13b.

[0036] A tensioner 20 is pivoted at fourth pivot 16 between the first wings 12a and 12b of lever arm 10, and is constituted by a body that can be accommodated between the second wings 21a and 21b of traction element 9, so as to be substantially shaped like a parallelepiped that has, at its ends, a fourth hole 22, which acts as seat for fourth pivot 16, and a fifth hole 23, which acts as seat for a fifth pivot 24 for the pivoting of tensioner 20 at a sixth pair of holes 25a and 25b formed at the base 26 of traction element 9.

[0037] Tensioner 20 has a through axial seat 27 for a tension release element constituted by a cam 28 that is rotatably associated at the lower surface 29 of tensioner 20 that faces base 18.

[0038] Rotary coupling between cam 28 and tensioner 20 can occur by means of, at the lower surface 29 of the tensioner, adapted seats 30a and 30b for adapted sixth pivots 31 that protrude laterally with respect to cam 28.

[0039] The cam is schematically S-shaped in a side view, so as to form a first tooth 32, which is adapted to abut at the overlying base 26 of traction element 9, and a second tooth 33, which interacts with a release actuator 34 constituted by a lever that is pivoted, at the other end, between the first wings 12a and 12b of lever arm 10 at the second pair of holes 14a and 14b by means of a seventh pivot 35.

[0040] The release actuator 34 can thus swing with respect to lever arm 10, its tip 36 interacting with the facing curved surface of second tooth 33.

[0041] Release actuator 34 therefore lies above the underlying end of tensioner 20 on which the fourth hole 22 is formed. Release actuator 34 rests on said end in the closure condition shown in figure 1.

[0042] Release actuator 34 also interacts with a flexible element 37 constituted by an adapted spring, which is rotatably associated with seventh pivot 35 at its ends and acts in contrast with release actuator 34 so as to force it towards the underlying end of tensioner 20.

[0043] The fastening device is also constituted by a covering element 38 that is constituted by a plate that has, at one end, a seventh hole 39 that acts as seat for an eighth pivot 40 for the pivoting of the covering element between the first wings 12a and 12b of lever arm 10 at the third pair of holes 15a and 15b.

[0044] The first wings 12a and 12b of lever arm 10 can also be arranged adjacent at a facing pair of second lateral shoulders 41a and 41b that are formed on tensioner 20 at the end for pivoting to fourth pivot 16.

[0045] The use of the device is as follows: starting from figure 1 which shows the device in the fastening condition, and therefore in closed condition, traction element 4 is engaged with engagement element 2.

[0046] In the condition shown in figure 1, therefore, the axis of fifth pivot 24 for pivoting tensioner 20 to traction element 9 is arranged, with respect to base 18, at a lower level than said base, relative to the axis of fourth pivot 16 for pivoting tensioner 20 to lever arm 10.

[0047] This arrangement allows the stable equilibrium of the device when closed, and lever arm 10 is therefore free from any stress.

[0048] In order to open the device, the user grips the free end of lever arm 10, performing a first lifting action, as shown in figure 2, in which the force applied by lever arm 10 is practically nil, except for the own weight of the lever arm and for any flexible elements optionally provided to keep the lever arm in lowered position.

[0049] Starting from the position shown in figure 2, the free end of release actuator 34 starts to interact with tooth 33 of cam 28, making the cam turn in the same direction about its sixth pivots 31.

[0050] The additional rotation imparted to the lever arm, as shown in figure 3, entails, by means of release actuator 34, the further rotation of cam 28, which in turn forces the lifting, with respect to base 18, of tensioner 20 until traction element 4 is loosened and therefore, until fastening is achieved.

[0051] Once traction element 4 has been loosened, lever arm 10 can be turned in the opposite direction, that is to say, clockwise: however, this rotation is passive, in that it does not affect the closure step or the opening step of the device.

[0052] The clockwise rotation of lever arm 10 therefore has the only function of repositioning the lever arm adjacent to first flap 3.

[0053] Simultaneously, the release of the tension applied to traction element 4 allows, also by means of the pressure that can be applied by the user's foot, the disengagement of first pivot 5 from engagement element 2, as shown for example in figure 6.

[0054] Said figure therefore shows the static open position of the device.

[0055] As regards the closure step, and therefore the dynamic step of the beginning of the active engagement stroke, starting from the condition of figure 6, it is necessary to turn lever arm 10 counterclockwise until traction element 4 is moved so that first pivot 5 interacts with engagement element 2, as shown in figure 7.

[0056] In this manner, first wings 12a and 12b, of lever arm 10, which are adjacent to the facing pair of second lateral shoulders 41a and 41b of tensioner 20, push lever arm 10 to assume a stable closure condition, shown in figure 10, in which, as in figure 1, the axis of fifth pivot 24 of tensioner 20 is arranged, with respect to base 18, at a lower level than the axis of fourth pivot 16 for pivoting tensioner 20 to lever arm 10.

[0057] In this step, both release actuator 34 and cam 28 are inactive, in that the cam is turned so that it is again located inside the axial through seat 27 of tensioner 20.

[0058] In this case, the subsequent clockwise rotation of lever arm 10 merely serves to reposition it adjacent to first flap 3. In this manner, release actuator 34 is automatically repositioned so that its tip is arranged proximate to the curved surface of second tooth 33 of cam 28, as shown in figure 1.

[0059] It is thus evident that the invention has achieved the above aim and objects, a device having been obtained in which the element that is adapted to actuate closure and opening is constituted by lever arm 10, which is moved in a single direction to achieve these steps, said direction being counterclockwise in the particular illustrated embodiment.

[0060] A rotation in the opposite direction applied to the lever arm has no function for actuating the closure and opening steps, as this rotation is passive because it allows only to reposition the lever arm, which is not affected by any tension, in the inactive position adjacent to first flap 3.

[0061] In this manner, the fastening and opening operations are easier, both because the force is always applied to the lever arm at the same direction and because the load begins to be applied when the lever arm is already raised with respect to first flap 3 and is therefore in a position that is more favorable for being gripped firmly by the user.

[0062] Furthermore, during the opening step, the force to be overcome is not that of traction element 9, but a force that is reduced by means of the servomechanisms constituted by cam 28 and by release actuator 34.

[0063] The operating sequence for opening and closure is therefore also simplified, since the user acts always and only on the lever arm, which is free from stresses once closure has occurred.

[0064] The device is of course susceptible of numerous modifications and variations, without departing from the scope of the same inventive concept.

[0065] Thus, for example, figures 13 to 21 illustrate another embodiment for a fastening device 101.

[0066] The device is constituted by an engagement element 102, such as a rack or one or more teeth, rigidly coupled to a first flap of the shoe.

[0067] The fastening device is also constituted by a traction element 104, which is preferably constituted by a pawl at one end of which, adjacent to the base, there is a first transverse pivot 105 that interacts with engagement element 102. A connecting element 109 is associated with the opposite end of said pawl by means of a second pivot 106.

[0068] The fastening device 101 is also constituted by a lever arm 110 having, at a first end 111, two first wings 112a and 112b, between which a first pair of holes is provided transversely and respectively, starting from the free end, for the pivoting of said lever arm, by means of a fourth pivot 116, between two first shoulders 117a and 117b that protrude from a base 118 that is rigidly coupled to the second flap of the sports shoe.

[0069] The end of a tensioner is associated at a third pivot 108 that is located at connecting element 109. The tensioner is constituted by two linkages 120a and 120b, and a longitudinal slot 142 is formed on the linkages thereat.

[0070] At the opposite end, the two linkages 120a and 120b are articulated, by means of an eighth pivot 143, outside the first wings 112a and 112b of lever arm 110.

[0071] A release actuator 134 is articulated at said eighth pivot 143 proximate to first end 111 and in the gap between the first wings 112a and 112b of lever arm 110. The length of release actuator 134 is such as to arrange tip 136 above the fourth pivot 116.

[0072] The device is also constituted by a tension release element 144 constituted by a detent that is freely pivoted, at one end, by means of a ninth pivot 145, to a slider 146 whose annular shape allows to arrange it slidingly adjacent to base 118 in the space below fourth pivot 116.

[0073] The free end of said detent is shaped complementarily to fourth pivot 116, and the detent cooperates with a flexible element, such as spring 147, that is interposed between the lower surface that faces base 118 and the base itself, so as to force said detent upward.

[0074] Slider 146 protrudes beyond fourth pivot 116 towards the second flap to be joined. The other end is pivoted, by means of a tenth pivot 148, to the end of connecting element 109 that does not interact with third pivot 108.

[0075] A third tooth 149 protrudes upward from the edge of slider 146 that is adjacent to ninth pivot 145. The third tooth is adapted to block any extraction of the slider beyond fourth pivot 116 towards the first flap to be joined.

[0076] The use of this second embodiment is as follows: starting from the closed condition, shown in figure 13, traction element 104 is engaged with engagement element 102, whereas release element 144 constituted by the detent is arranged in abutment, by means of spring 147, against fourth pivot 116, as shown in figure 17.

[0077] The sliding of slider 146 with respect to base 118 is thus blocked, keeping the device in a stable closure position with the lever arm free from stresses.

[0078] The dynamic step for starting the active release stroke occurs after a first rotation applied to the lever arm and therefore starting, for example, from the angular position shown in figure 14.

[0079] Starting from this position, release actuator 134 starts to interact with release element 144, applying thereon a pressure in contrast with spring 147 to force it to disengage from fourth pivot 116.

[0080] By then continuing a counterclockwise rotation of lever arm 110, the pressure applied by release actuator 134 on release element 144 causes the release element to disengage from fourth pivot 116, thus allowing slider 146 to slide freely towards the first flap to be joined, as shown in figures 15 and 18.

[0081] The stroke of slider 146 is determined by the length of slots 142, whereas third tooth 149 prevents any accidental extractions of the slider with respect to base 118, since said third tooth would abut against fourth pivot 116.

[0082] Starting from the disengagement of the detent from fourth tooth 116, fastening is loosened; once traction element 104 has been loosened, the passive step of the clockwise rotation of the lever arm begins, thus allowing to reposition it, inactive, adjacent to the first flap.

[0083] One thus achieves the open position of the device as shown in figure 16.

[0084] The dynamic step for starting the active stroke of the device to close it occurs by moving first pivot 105 so that it interacts with engagement element 102.

[0085] In this manner, as shown in figure 19, when a counterclockwise rotation is applied to lever arm 110, the linkages that constitute the tensioner push slider 146 until the free end of release element 144 engages fourth pivot 116.

[0086] During this step, release actuator 134 is inactive.

[0087] Then the final engagement step is achieved; during this step, lever arm 110 is again free from stresses and can therefore be repositioned adjacent to the first flap to be joined, in the inactive position, as shown in figures 20 and 21.

[0088] Therefore, this solution, too, like the previous one, allows to achieve the intended aim and objects.

[0089] The materials and the dimensions that constitute the individual components of the device may of course also be the most pertinent according to the specific requirements.

[0090] Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. Fastening device, particularly for sports shoes, comprising an engagement element (2,102) rigidly coupled to a first flap (3,103) and a traction element (4,104) cooperating with said engagement element, said traction element being operatively connected to a lever arm (10,110) that is freely transversely pivoted, at a first end (11,111), between the shoulders (17a,17b) of a base (18), said base being rigidly coupled to a second flap (19), characterized in that said lever arm (10,110) actuates the opening and closure operations of said device upon a rotation applied to it in the same direction.

2. Device according to claim 1, characterized in that said lever arm (10,110) can alternatively actuate, upon a rotation that can be imparted to said arm in only one direction, the activation of the closure step and of the opening step of the device, whereas for a rotation in the opposite direction said lever arm has no actuating function for said closure and opening steps, said rotation being passive, since it is adapted to allow only to reposition said lever arm, which is free from any tension, in the inactive position adjacent to said first flap.

3. Device according to claim 2, characterized in that said engagement element comprises a rack rigidly coupled to said first flap, and said traction element comprises a pawl at one end of which, adjacent to the base, there is a first transverse pivot (5) that interacts with said engagement element; a connecting element (7) being in turn associated with the other end of said pawl by means of a second pivot (6), said connecting element being in turn associated, by means of an adapted third pivot (8), at the free ends of said traction element, characterized in that said lever arm has, at a first end, two first wings (12a,12b), between which a first pair of holes (13a,13b), a second pair of holes (14a,14b), and optionally a third pair of holes (15a,15b) are formed transversely and respectively starting from the free end.

4. Device according to claim 3, characterized in that said lever arm is transversely freely pivoted, by means of a fourth pivot (16), between said two first shoulders (17a,17b) that protrude from said base (18) that is rigidly coupled to the second flap (19) to be joined of said sports shoe, characterized in that said fourth pivot (16) passes at said first pair of holes (13a,13b), a tensioner (20) being pivoted to said fourth pivot between said first wings.

5. Device according to claim 4, characterized in that said tensioner (20) is constituted by a body that can be accommodated between second wings (21a,21b) of said traction element, said body being substantially shaped like a parallelepiped that has, at its ends, a fourth hole (22) that acts as seat for said fourth pivot (16) and a fifth hole (23) that acts as seat for a fifth pivot (24) for pivoting said actuator at a sixth pair of holes (25a,25b) formed at said base of said traction element.

6. Device according to claim 5, characterized in that said tensioner (20) has an axial through seat (27) for a tension release element (28), said tension release element being constituted by a cam (28) that is rotatably associated at the lower surface (29) of said tensioner (20), which faces said base, said cam having adapted sixth pivots (31) that protrude laterally therefrom and are adapted to be arranged rotatably at adapted and complementarily shaped seats formed on the lower surface of said tensioner.

7. Device according to claim 6, characterized in that said cam (28) is substantially S-shaped in a lateral view, so as to form a first tooth (32), which is adapted to abut at said overlying base (26) of said traction element, and a second tooth (33), which interacts with a release actuator (34), said release actuator being constituted by lever (34) that is pivoted, at the other end, between said first wings (12a,12b) of said lever arm (10) at said second pair of holes (14a,14b) by means of a seventh pivot (35), said release actuator (34) swinging with respect to said lever arm, its tip (36) interacting with the facing curved surface of said second tooth (33) of said cam.

8. Device according to claim 7, characterized in that said release actuator (34) lies above the underlying end of said tensioner (20) on which said fourth hole (22) is formed, said release actuator resting on said end in the condition for closing said device.

9. Device according to claim 8, characterized in that said release actuator (34) interacts with a flexible element (37) constituted by an appropriate spring that is adapted to force said release actuator towards the underlying end of said tensioner (20).

10. Device according to one or more of the preceding claims, characterized in that it comprises a covering element (38) constituted by a plate that has, at one end, a seventh transverse hole that acts as seat for an eighth pivot (40) for pivoting between said first wings of said lever arm at said third pair of holes.

11. Device according to one or more of the preceding claims, characterized in that, when an adapted rotation is applied to said lever arm (10), said first wings of said lever arm (10) can be arranged adjacent at two second lateral shoulders (41a,41b) formed on said tensioner at the end for pivoting to said fourth pivot (16).

12. Device according to one or more of the preceding claims, characterized in that said lever arm (10), starting from the closed condition, is not affected by any forces up to a preset angle of rotation that can be applied to it with respect to said first flap.

13. Device according to claim 12, characterized in that beyond said rotation angle, the movement of said lever arm (10) entails the interaction of said free end of said release actuator (34) with said second tooth (33) of said cam (28), so as to force said cam to rotate in the same direction about said sixth pivots; the rotation of said cam (28), applied thereto by said release actuator (34), forces the lifting, with respect to said base, of said tensioner (20) until said traction element is loosened; after the step for loosening said traction element (4), said lever arm (10) can be turned in the opposite direction so as to allow to reposition said lever arm, free from tensions, adjacent to said first flap (3); starting from the previous position, when said lever arm (10) is rotated again, it forces said first pivot (5) to engage at said engagement element (2), said first wings abutting against said pair of second lateral shoulders that are provided on said tensioner, so as to push said tensioner until it is in a stable closure condition, in which the axis of said fifth pivot is arranged, with respect to said base, at a lower level than the axis of said fourth pivot for the pivoting of said tensioner to said lever arm.

14. Device according to one or more of the preceding claims, characterized in that the end of a tensioner, constituted by two linkages (120a,120b) on which a longitudinal slot (142) is formed, is associated at said third pivot that is located at said connecting element.

15. Device according to claim 14, characterized in that said pair of linkages (120a,120b) is articulated, at its opposite end, by means of an eighth pivot (143), outside said first wings (112a,112b) of said lever arm (110) at said third pair of holes.

16. Device according to claim 15, characterized in that a release actuator (134) is articulated at said eighth pivot, proximate to said first end of said lever arm (110) and in the interspace between said first wings (112a,112b), the length of said release actuator being such as to arrange its tip (136) above said fourth pivot (116).

17. Device according to claim 16, characterized in that it comprises a tension release element (144) that is constituted by a detent that is freely pivoted, at one end, by means of a ninth pivot (145), transversely to a slider (146).

18. Device according to claim 17, characterized in that said slider (146) has such an annular shape that it can be slidingly arranged adjacent to said base (118) in the space below said fourth pivot.

19. Device according to claim 18, characterized in that said detent has a free end that is shaped complementarily with respect to said fourth pivot (116), said detent cooperating with a flexible element (147), such as a spring, that is interposed between said base and the lower surface of said detent so as to force it to move away from said base.

20. Device according to claim 19, characterized in that said slider (146) protrudes beyond said pivot (116) towards said second flap to be joined, the end of said connecting element that does not interact with said third pivot being pivoted to the other end of said slider by means of a tenth pivot (148).

21. Device according to claim 20, characterized in that a third tooth (149) protrudes upward from the transverse edge of said slider (146) that is adjacent to said ninth pivot (145), said third tooth being is suitable to block any extraction of said slider beyond said fourth pivot towards said first flap to be joined.

22. Device according to one or more of the preceding claims, characterized in that starting from the closed condition, beyond a given rotation angle of said lever arm (110), said release actuator (134) interacts with said release element (102), applying thereon a pressure that is in contrast with said spring to force its disengagement from said fourth pivot; when said lever arm (110) is rotated further in the same direction, said release actuator (134) causes the disengagement of said release element (102) from said fourth pivot (116), allowing said slider (146) to slide freely towards said first flap to be joined, the stroke of said slider being determined by the length of said longitudinal slots (142); starting from the condition in which said traction element is loosened, a rotation applied to said lever arm (110) in the opposite direction is passive, since said lever arm is not affected by forces and can be repositioned adjacent to said first flap; starting from the preceding position, a new rotation applied to said lever arm (110) leads to the interaction of said first pivot (105) with said engagement element, said linkages moving said slider in the opposite direction with respect to said engagement element until said release element can engage said fourth pivot so as to achieve the stable closure condition and relieve said lever arm of all forces.

Drawing