WO2019150338A1 - Draught-excluder device with delayed actuation - Google Patents

Abstract

An improved draught-excluder device (1) with delayed actuation, adapted to be applied to the bottom edge (B) of a door (P) hinged to a frame (T), the device (1) comprising an enclosure (2) with a seal (3) therein for sealing interaction with a sealingly interact with a sill (S), drive means (6) which act on the seal (3) to move it between a raised inoperative position and a lowered operating position, an actuator (15) associated with the drive means (6) for control actuation thereof by interaction with the frame (T) as the door (P) is being closed and delay means (22) which act on the drive means (6) to delay operation thereof. The drive means (6) comprise a slide (7) which has an appendage (8) with an end edge (9) adapted to interact with the delay means (22) and is operably connected to the seal (3), and the delay means (22) comprise a movable element (23) having a first substantially vertical counteracting surface (24) which is adapted to act against the end edge (9) of the slide (7) when the seal (3) is in the raised inoperative position, and a second slide surface (25) inclined to the first surface (24) for causing snap release of the movable element (23) from the end edge (9) of the slide (7) as well as delayed sliding of the latter and movement of the seal (3) to the operating lowered position. The end edge (9) is substantially flat and vertical and the movable element (23) is a pivoting lever (23') that pivots on the enclosure (2) about a substantially horizontal axis (X) and has a proximal end portion (26) with the first counteracting surface (24) and the second slide surface (25). The actuator (15) comprises a longitudinal elongate element (27) and the lever (23') comprises a substantially vertical stop member (28). The elongate element (27) is adapted to contact the stop member (28) upon actuation of the actuator (15) to cause the end edge (9) to move from the first counteracting surface (24) to the second slide surface (25) when the door (P) is closed.

Description

DRAUGHT-EXCLUDER DEVICE WITH DELAYED ACTUATION

Field of The Invention

[0001] The present invention generally finds application in the field of heat and sound insulating devices, and particularly relates to an improved draught- excluder device with delayed actuation and snap movement.

Background art

[0002] Draught-excluder devices are known to be applied to the bottom edge of a door or window leaf mounted to a frame and to be adapted to at least partially close off any gap occurring between the leaf and the sill.

[0003] Generally, these devices include a seal made of an elastically yielding material, which is adapted to sealingly interact with the sill to prevent air infiltration.

[0004] In addition, these draught-excluder devices comprise drive means for driving the seal between a lifted position above the floor and a lowered position in contact with the floor.

[0005] These devices also comprise an actuator which projects out of the door edge and is adapted to interact with the frame as the door is being closed, to cause the seal to move from the lifted position to the lowered position.

[0006] In some of these draught-excluder devices, delay means are provided which act on the drive means to delay the downward movement of the seal as the door is being closed.

[0007] Nevertheless, one drawback of these known devices is that the delay means are also operated as the door is being opened, thereby causing delayed lifting of the seal and rubbing thereof on the floor for a non-negligible time.

[0008] Such rubbing of the seal on the floor causes deformation and wear, and requires periodic seal replacement after repeated use.

[0009] In addition, such rubbing of the seal on the floor hinders the user in opening and closing the door.

[0010] In an attempt to at least partially obviate these drawbacks draught- excluder devices have been developed which comprise delay means adapted to only act on the drive means as the door is being closed, to allow the seal to be immediately lifted as the door is being opened.

[0011] EP2924224 discloses a draught-excluder device which comprises drive means actuated by the actuator and comprising a longitudinally sliding slide operably associated with the seal.

[0012] In this known device, the slide may interact with the piston of a downstream shock-absorber to delay the movement of the seal from the lifted position to the lowered position that is driven by the drive means as the door is being closed.

[0013] Conversely, as the door is being opened, the slide instantaneously separates from the piston of the shock absorber for the seal to be immediately lifted.

[0014] Nevertheless, this arrangement has the drawback of operating with inadequate response times when the door is partially opened and then closed again before the piston of the shock absorber moves back to its initial rest position.

[0015] Furthermore, a minor interaction of the actuator with the fixed frame will overcome the counteracting force of the delay means. Therefore, the delayed downward movement of the seal may start before the door is completely closed.

[0016] Rubbing of the seal on the floor during movement of the door is reduced to a limited extent due to the aforementioned drawbacks.

[0017] An additional drawback of this arrangement is that this draught- excluder device does not ensure an optimal sealing effect of the seal when it contacts the sill.

[0018] A further drawback of this arrangement is that certain parts of the aforementioned draught-excluder device are highly sensitive to temperature changes and are expensive.

Technical Problem

[0019] In view of the prior art, the technical problem addressed by the present invention consists in causing delayed lowering of the seal only when the leaf is completely closed, to thereby completely prevent the seal from rubbing on the floor. Disclosure of the invention

[0020] The object of the present invention is to obviate the above drawbacks, by providing an improved draught-excluder device with delayed actuation that is highly efficient and relatively cost-effective.

[0021] A particular object of the present invention is to provide a draught- excluder device as described hereinbefore that can ensure delayed lowering of the seal when the door is completely closed.

[0022] Another object of the present invention is to provide a draught- excluder device as described hereinbefore that completely prevents the seal from rubbing on the floor.

[0023] A further particular object of the present invention is to provide a draught-excluder device as described hereinbefore that ensures an optimal sealing effect of the seal on the sill.

[0024] Another object of the present invention is to provide to provide a draught-excluder device as described hereinbefore in which the thrust of the actuator is entirely designed to maintain a constant pressure of the seal on the floor when the door is closed.

[0025] Another object of the present invention is to provide a controllably movable draught-excluder device that has simple maintenance.

[0026] Yet another object of the present invention is to provide a controllably movable draught-excluder device that affords very simple adjustment of the delay with which the flexible strip is lowered, such delay being constant with time.

[0027] Another object of the present invention is to provide a draught- excluder device having parts with reduced sensitivity to temperature changes and lower costs.

[0028] These and other objects, as more clearly explained hereinafter, are fulfilled by a draught-excluder device with delayed actuation, designed to be attached to the bottom edge of a door hinged to a frame, as defined in claim 1 , the device comprising an enclosure with a seal therein for sealing interaction with a sill, drive means which act on the seal to move it between a raised inoperative position and a lowered operating position and an actuator associated with the drive means to control actuation thereof by interaction with the frame as the door is being closed.

[0029] In addition, the draught-excluder device comprises delay means acting on the drive means to delay operation thereof, which comprise a slide having an appendage with an end edge adapted to interact with the delay means and operably connected to the seal.

[0030] The delay means comprise a movable element having a first substantially vertical counteracting surface which is adapted to act against the end edge of the slide when the seal is in the idle lifted position, and a second slide surface inclined to the first surface for causing snap release of the movable element from the end edge of the slide as well as delayed sliding of the latter and movement of the seal toward the operating lowered position.

[0031] In a peculiar aspect of the invention, the end edge is substantially flat and vertical and the movable element is a pivoting lever that pivots on the enclosure about a substantially horizontal axis and has a proximal end portion with the first counteracting surface and the second slide surface. The actuator comprises a longitudinal elongate element and the lever comprises a substantially vertical stop member. Furthermore, the elongate element is adapted to contact the stop member upon actuation of the actuator to cause the end edge to move from the first counteracting surface to the second slide surface when the door is closed.

[0032] As a result of these features, delayed lowering of the seal only occurs when the door is completely closed and increases the sealing effect of the seal in the operating position.

[0033] Furthermore, delayed lowering of the seal is caused by a shock- absorber that is located downstream from the movable element and is adapted to interact with the distal end of the latter to delay its movement.

[0034] As the door is being opened, the movable element is reset both by the shock-absorber, which overcomes the thrust of the drive means when the actuator does not interact with the frame of the door, and by an elastic return member attached to the enclosure.

[0035] Advantageous embodiments of the invention are obtained in accordance with the dependent claims.

Brief Description of The Drawings

[0036] Further characteristics and advantages of the invention will become more apparent upon reading of the detailed description of a few preferred, non exclusive embodiments of a draught-excluder device with delayed actuation according to the invention, which is described as non-limiting examples with the help of the accompanying drawings in which:

FIG. 1 is a broken-away side view of the draught-excluder device of the invention;

FIG. 2 is an enlarged broken-away side view of a first detail of the device of Fig. 1 ;

FIG. 3 is an enlarged broken-away side view of a second detail of the device of Fig. 1 ;

FIG. 4 is an enlarged broken-away side view of a detail of Fig. 3 in a first operating position;

FIG. 5 is an enlarged view of a detail of Fig. 4;

FIG. 6 is an enlarged broken-away side view of a detail of Fig. 3 in a second operating position;

FIG. 7 is a broken-away side view of the second detail of the device of FIG. 1 according to an alternative embodiment;

FIG. 8 is a side view of a detail of the device of the invention according to an alternative embodiment;

FIGS. 9 to 1 1 are broken-away side views of the draught-excluder device in different operating configurations.

Detailed description of a preferred exemplary embodiment

[0037] The above figures show a draught-excluder device with delayed actuation, generally designated by numeral 1 , which is designed to be attached to the bottom edge B of a door P hinged to a frame T secured to an opening formed in a wall.

[0038] As is known per se, the frame T comprises a pair of vertical posts M, M', which are joined by a horizontal cross member and the door P may be hinged to one of the posts M to rotate about a substantially vertical axis of rotation.

[0039] In its basic embodiment, as best shown in FIG. 1 , the draught- excluder device 1 of the invention comprises a box-like enclosure 2 that is designed to be inserted into a groove formed in the bottom edge B of the door P and that defines a longitudinal axis L.

[0040] The box-like enclosure 2 comprises a seal 3 therein for interaction with a sill or floor S to sealingly block the passage of air.

[0041] The seal 3 may be made of an elastically yielding material preferably selected from the group comprising elastomers or polymeric materials and may have an upper portion 4 with at least one lower appendage 5 extending therefrom to interact with the sill S.

[0042] Drive means 6 are accommodated in the box-like enclosure 2 and act on the seal 3 to move it from a raised inoperative position, spaced apart from the sill S to an operating lowered position in contact with the sill S and vice versa.

[0043] As explained below, the movement of the seal 3 from the raised position to the lowered position, caused by the drive means 6, is a snap movement.

[0044] The drive means 6 comprise at least one slide 7, which is adapted to translationally move along a predetermined longitudinal stroke, is operably connected to the seal 3 and has an appendage 8 with a substantially flat and vertical end edge 9.

[0045] In addition, the drive means 6 may comprise a pair of connecting rods 10A, 10B, one of which 10a is adapted to connect the slide 7 to the seal 3.

[0046] In particular, in the embodiment of the figures, the device 1 may comprise a pair of connecting rods 1 1 , 1 1 ' with one end 20, 20' hinged to corresponding first and second anchor elements 21 , 21 ', which are designed to be removably coupled to the upper portion 4 of the seal 3.

[0047] The other end 13A of the connecting rod 10A is hinged to the slide 7, whereas the end 13B of the other connecting rod 10B is hinged to a fixed support 14. [0048] This connecting arrangement will provide a four-bar linkage, whose sides are formed by the slide 7, the connecting rod 10A, the seal 3 and the other connecting rod 10B respectively.

[0049] An actuator 15 is also provided, which is associated with the drive means 6 to control actuation thereof when it contacts the post M of the frame T as the door P is being closed. Therefore, the drive means 6 are used to transfer motion from the actuator 15 to the seal 3 once the door P has been closed.

[0050] As shown in FIG.1 , the actuator 1 may comprise a tubular element 16 having a flat end portion 17 projecting out of the enclosure 2 and adapted to interact with the post M of the frame T.

[0051] The actuator 15 is adapted to longitudinally move between an extended position, in which it does not interact with the post M when the door P is open and a retracted position in which it contacts the post M when the door P is closed.

[0052] In its retracted position, the actuator 15 will be adapted to interact with a longitudinal pin 18 also located in the enclosure 2 and having one end 19 rigidly joined to the slide 7.

[0053] In addition, a compression spring 20 is provided, which is interposed between the actuator 15 and the slide 7 and is fitted on the longitudinal pin 18. In particular, the compression spring 20 has ends 20A, 20b which interact with the actuator 15 in the retracted position and the slide 7 respectively.

[0054] In its retracted position, the actuator 15 may cause compression of the compression spring 20. The latter may have a spring modulus selected to transfer a predetermined longitudinal force to the slide 7.

[0055] The force Fi applied by the compression spring 20 to the four-bar linkage 24 through the slide 7 will cause the seal 3 to move downwards, while remaining substantially parallel to the longitudinal axis L.

[0056] Advantageously, each connecting rod 10A, 10B comprises a respective return spring 21 which can rotate and lift it, with the seal 3, as the door P is being opened, i.e. when the actuator 15 does no longer act upon the slide 7 through the compression spring 20.

[0057] Delay means 22 are further provided, which act on the drive means 6 to delay operation thereof and movement of the seal 3 from the raised position to the lowered position.

[0058] In particular, the drive means 6 interact with the delay means 22 through the end edge 9 of the appendage 8 of the slide 7, as best shown in FIGS. 3 and 4.

[0059] The delay means 22 comprise a movable element 23 having a first substantially vertical counteracting surface 24 adapted to act against the end edge 9 of the appendage 8 of the slide 7 when the seal 3 is in the raised inoperative position, and hence when the actuator 15 does not interact with the frame T of the door P. This operating state is shown in FIGS. 3 to 5.

[0060] Furthermore, the movable element 23 comprises a second slide surface 25 inclined to the first surface 24 for causing snap release of the movable element 23 from the end edge 9 of the slide 7, as shown in FIG. 6.

[0061] The release of the movable element 23 causes a delayed longitudinal sliding movement of the slide, which was previously locked by the movable element, under the thrust of the actuator 15 and the compression spring 20, as well as a delayed movement of the seal 3 to its operating lowered position.

[0062] This arrangement only causes delayed movement of the seal 3 when the door P is completely closed, which will prevent rubbing of the seal 3.

[0063] Moreover, in the operating position, the slide 7 is no longer retained by the movable element 23 and may terminate its longitudinal translation as shown in FIGS. 6 and 1 1 , such that the force exerted by the compression spring 20 will be entirely discharged on the seal 3 through the slide 7, which will improve the sealing effect at the sill S.

[0064] In a peculiar aspect of the invention, the movable element 23 consists of a pivoting lever 23', which pivots on the box-like enclosure 2 about a substantially horizontal and transverse axis X. Therefore, the above described snap release occurs by the pivotal downward movement of the lever 23 about the axis X. [0065] The lever 23' comprises a proximal end portion 26 with the first counteracting surface 24 and the second slide surface 25.

[0066] Advantageously, as shown in FIGS. 3, 6 and 8, the actuator 15 comprises a longitudinal elongate element 27 and the lever 23' comprises a substantially vertical stop member 28.

[0067] The elongate element 27 comprises a fastening base mounted between the actuator 15 and the compression spring 20 and is adapted to contact the stop member 28 upon actuation of the actuator 15.

[0068] The contact of the elongate element 27 with the stop member 28 first causes the end edge 9 of the slide 7 to move from the first counteracting surface 24 to the second slide surface 25 when the door P is closed, as shown in FIG. 9, and then causes snap release of the end edge 9 from the second slide surface 25 by the pivotal movement of the lever 23', as shown in FIG. 10.

[0069] The first counteracting surface 24 may be formed on the proximal end portion 26 below the second slide surface 25 and may be adjacent thereto to form a predetermined inclination angle a, as shown in FIG. 5.

[0070] By changing the spring modulus of the compression spring 20 and the inclination a between the first counteracting surface 24 and the second slide surface 25, the timing of the delay for the downward movement of the seal 3 may be adjusted.

[0071] It will be appreciated that the longitudinal translational travel permitted by the appendage 8 due to the compression spring 20 is smaller than or equal to the longitudinal translation travel of the elongate element 27 due to the action of the actuator 15.

[0072] In an alternative embodiment of the invention, as shown in FIG. 8, the elongate element 27 may be also replaced by an equivalent element which is adapted to contact the stop member 28, without departure from the scope of the present invention.

[0073] In this alternative embodiment, the elongate element 27 may consist of a longitudinal rod 27' having a chamfered end for interaction with the stop member 28.

[0074] As shown in the figures, the delay means 22 may further comprise a well-known oil hydraulic shock absorber 29 having a longitudinally sliding piston 31 accommodated in a support element 30 that is rigidly joined to the enclosure 2 and is located downstream from the lever 23'.

[0075] The piston 31 of the shock absorber 29 is adapted to interact with a distal end portion 32 of the lever 23' to delay the snap release by pivoting it from the end edge 9 of the slide 7.

[0076] Namely, the piston 31 interacts with the distal end portion 32 of the lever 23' via a counteracting element 33 that is hinged to the support 30 of the shock absorber 29 and is interposed between the lever 23 and the shock absorber 29.

[0077] Conveniently, the counteracting element 33 may comprise a first wall 34 that faces the shock absorber 29 and has a seat 35 for receiving the stem 36 of the piston 31 and a second wall 37 that faces the lever 23' and is adapted to interact with its distal end portion 32.

[0078] The second wall 37 comprises a flat outer surface, whereas the distal end 32 of the lever 23' comprises a rounded edge that interacts with the flat surface and rotates thereupon as a result of the pivotal movement of the lever 23' about the axis X.

[0079] In an alternative embodiment, the delay means 22 may comprise a delay spring 22A in lieu of the oil hydraulic shock absorber 29, as best shown in FIG. 7.

[0080] As compared with the shock absorber 29, the delay spring 22A has the advantage of having a lower cost and being less sensitive to temperature changes.

[0081] Preferably, the delay spring 22A has a conical type and may comprise a longitudinally sliding stem 22B, whose movement is similar to that of the piston 31 of the shock absorber 29.

[0082] Furthermore, the delay spring 22a is also accommodated in a support element 30 that is rigidly joined to the enclosure 2 and is located downstream from the lever 23'. In this configuration, the spring 22A may have one end 22c connected to a transverse wall 30A of the support element 30.

[0083] The stem 22B of the spring 22A is adapted to interact with the distal end portion 32 of the lever 23' to delay the snap release by pivoting it from the end edge 9 of the slide 7.

[0084] Namely, the stem 22B interacts with the distal end portion 32 of the lever 23' via the counteracting element 33 as described above, which is interposed between the lever 23 and the spring 22A.

[0085] The device 1 comprises an elastic return member 38 having a first end 38A associated with the enclosure 2 and a second end 38B associated with the proximal end portion 26 of the lever 23'.

[0086] This elastic member 38 acts on the lever 23' to pull it upwards, to thereby maintain the first counteracting surface 24 in contact with the end edge 9 of the slide 7 when the door P is open.

[0087] Furthermore, the elastic return member 38 cooperates with the shock absorber 29 or with the delay spring 22A, to move the lever 23' back to the operating position with the first counteracting surface 24 in contact with the end edge 9 of the appendage 8 when the door P is being opened and the slide 7 moves longitudinally in the opposite direction.

[0088] This configuration allows the seal 3 to move from the lowered position to the raised position, while limiting the rubbing movement thereof on the floor as the door P is being opened.

[0089] An operating sequence of the draught-excluder device as a door P is being closed/opened will be now described, with particular reference to FIGS. 1 and 9 to 1 1 .

[0090] Namely, when the door P is open, the actuator 15 is in the extended position, and the seal 3 assumes the lifted position, at a distance from the sill S, as shown in FIG. 1 .

[0091] In this operating state, the end edge 9 of the appendage 8 of the slide 7 abuts the first counteracting surface 24 of the lever 23' and the elongate element 27 is spaced apart from the stop member 28.

[0092] In addition, the piston 31 of the shock absorber 29, or the stem 22B of the spring 22A, acts on the counteracting element 33 by pushing it outwards and the elastic member 38 pulls the lever 23’ upwards.

[0093] As the door P is being closed, the end portion 17 of the actuator 15 contacts the post M and this contact will cause a longitudinal translational movement of the actuator 15 to a maximum predetermined extent, to its retracted position.

[0094] The movement of the actuator 15 will cause the compression spring 20 to be compressed and the force Fi to be transferred to the slide 7 and the appendage 8.

[0095] Nevertheless, in this particular state the force Fi is initially counteracted and balanced by a counteracting force F2 exerted by the piston 31 of the shock absorber 29, or by the stem 22B of the spring 22B, which acts on the lever 23' via the counteracting element 33.

[0096] When the thrust force Fi overcomes the counteracting force F2, first the end edge 9 of the slide 7 moves from the first counteracting surface 24 to the second slide surface 25, as shown in FIG. 9.

[0097] Then, the proximal end portion 26 of the lever 23' is snap released from the end edge 9 of the slide 7 and the lever 23' pivots downwards about the axis X.

[0098] As shown in FIG. 10, the downward pivotal movement of the lever 23' causes the rounded edge of the distal end portion 32 to rotate on the second wall 37 of the counteracting element 33.

[0099] This movement urges the counteracting element 33 to rotate upwards and as a result the piston 31 translationally moves into the shock absorber 29, thereby compressing the fluid therein.

[00100] In the alternative embodiment as shown in FIG. 7, the stem 22B longitudinally moves inwards and compresses the delay spring 22A.

[00101] In this state, the slide 7 is no longer locked by the counteracting surface 24 of the lever 23’ and will move longitudinally in the same direction as the force Fi, thereby causing the connecting rod 10A to rotate and the seal 3 to be progressively lowered to contact with the sill S.

[00102] Thus, as shown in FIG. 1 1 , in this operating state, the slide 7 is located above the proximal end portion 26 of the lever 23' and the latter contacts with the bottom face 39 of the appendage 8.

[00103] Therefore, in spite of the action of the elastic return member 38, the complete pivotal movement of the lever 23' in the direction opposite to the one described above is prevented at least as long as the slide 7 remains above the proximal end portion 26 of the lever 23' due to the action of the compression spring 20 and the actuator 15.

[00104] Then, as the door P is being opened, the compression of the compression spring 20 will be relieved on the actuator 15, thereby causing it to move back into its extended position.

[00105] The actuator 15 will move the pin 18 outwards and the latter will cause instantaneous displacement of the slide 7 and the end edge 26 of the appendage 8.

[00106] The backward movement of the slide 7 allows the lever 23' to be pulled upwards by the rotation of the elastic return member 38, such that the end edge 9 of the appendage 8 will abut again the first counteracting surface 24.

[00107] The piston 31 of the shock absorber 29, or the stem 22B of the spring 22B, that was loaded by the upward movement of the counteracting element 33, is also released and causes the counteracting element 33 to rotate downwards and the lever 23’ to pivot upwards by acting on the rounded distal end portion 32.

[00108] All the details hereof may be replaced by other technically equivalent parts, and the materials may vary depending on different needs, without departure from the scope of the invention.

Industrial Applicability

[00109] The present invention may find application in industry, because it can be produced on an industrial scale by factories in the field of heat and sound insulation devices for doors and windows and may be used for various applications, e.g. for commercial, industrial and private purposes.

Claims

1 . An improved draught-excluder device (1 ) with delayed actuation, adapted to be attached to the bottom edge (B) of a door (P) hinged to a frame (T), which device (1 ) comprises an enclosure (2) having therein:

a seal (3) adapted to sealingly interact with a sill (S) and drive means (6) acting on said seal (3) to move it between a raised inoperative position and a lowered inoperative position;

an actuator (15) associated with said drive means (6) to control actuation thereof as a result of the interaction with the frame (T) as the door (P) is being closed;

delay means (22) acting upon said drive means (6) to delay operation thereof;

wherein said drive means (6) comprise a slide (7) having an appendage (8) with an end edge (9) adapted for interaction with said delay means (22) and operably connected to said seal (3);

wherein said delay means (22) comprise a movable element (23) having a first substantially vertical counteracting surface (24) which is adapted to act against the end edge (9) of said slide (7) when said seal (3) is in the raised inoperative position, and a second slide surface (25) inclined with respect to said first surface (24) for causing snap release of said movable element (23) from said end edge (9) of said slide (7) as well as delayed sliding of the latter and movement of said seal (3) toward said operating lowered position;

characterized in that said end edge (9) is substantially flat and vertical and said movable element (23) is a pivoting lever (23') that pivots on said enclosure (2) about a substantially horizontal axis (X) and has a proximal end portion (26) with said first abutment surface (24) and said second slide surface (25), said actuator (15) comprising a longitudinal elongate element (27) and said lever (23') comprising a substantially vertical stop member (28), said elongate element (27) being adapted to contact said stop member (28) upon actuation of said actuator (15) to cause said end edge (9) to move from said first counteracting surface (24) to said second slide surface (25) when the door (P) is closed.

2. A device as claimed in claim 1 , characterized in that it comprises an elastic return member (38) which acts on said lever (23') to pull it upwards, to thereby maintain said first counteracting surface (24) in contact with said end edge (9) of said slide (7) when the door (P) is open.

3. A device as claimed in claim 1 , characterized in that said first counteracting surface (24) is formed on said proximal end portion (26) below said second slide surface (25).

4. A device as claimed in claim 3, characterized in that said first counteracting surface (24) is adjacent to said second slide surface (25) and forms a predetermined inclination angle (a) with respect to the latter.

5. A device as claimed in claim 1 , characterized in that said lever (23') comprises a distal end portion (32) which is adapted to interact with a shock absorber (29) having a longitudinally sliding piston (31 ), said shock absorber (29) being adapted to delay the pivotal snap release of said lever (23') from the end edge (9) of said slide (7).

6. A device as claimed in claim 5, characterized in that it comprises a support element (30) which is rigidly joined to said enclosure (2) and is adapted to accommodate said shock absorber (29), a counteracting element (33) being provided, which is hinged to said support element (30) and is interposed between said piston (31 ) and the distal end (32) of said lever (23').

7. A device as claimed in claim 5, characterized in that said distal end (32) comprises a rounded edge adapted to interact with a substantially flat surface of said counteracting element (33).

8. A device as claimed in claim 1 , characterized in that said delay means (22) comprise a delay spring (22A) coupled to a sliding rod (22B) and accommodated in a support element (30) that is rigidly joined to said enclosure (2), said stem (22B) being adapted to interact with a distal end portion (32) of said lever (23') to delay its pivotal snap release from the end edge (9) of said slide (7).

9. A device as claimed in claim 1 , characterized in that it comprises a compression spring (12) interposed between said actuator (15) and said slide (7).

10. A device as claimed in claim 1 , characterized in that said drive means (6) comprise a pair of connecting rods (10A, 10B), one of said connecting rods (10A) having a first end (1 1 A) hinged to said slide (7) and a corresponding second end (13A) hinged to a first anchor element (12A) which is removably coupled to said seal (3), the other of said connecting rods (10B) having a first end (1 1 B) coupled to a fixed support (14) and a corresponding second end (13B) hinged to a second anchor element (12B) removably coupled to said seal (3) to form a four-bar linkage.