WO2005116374A1

WO2005116374A1 - Door locking device, particularly for sliding or swinging glass doors and the like

Info

Publication number: WO2005116374A1
Application number: PCT/IT2004/000311
Authority: WO
Inventors: Gersam Meroni
Original assignee: Serrature Meroni S.P.A.
Priority date: 2004-05-27
Filing date: 2004-05-27
Publication date: 2005-12-08
Also published as: ATE407279T1; DE602004016399D1; EP1756385A1; EP1756385B1

Abstract

The invention relates to a locking device (100) for doors (101, 102) particularly sliding glass doors and the like, comprising: a lock unit (2) to be controlled by a key (20) such as to lock the doors in a closed position and unlock them to allow the relative motion thereof, fastening removable means (1) to at least one of the doors suitable to support the lock unit (2) and mechanically cooperate with the same to lock the doors in said closing position. The device is characterized in that said fastening means are provided with at least one elastically yielding element (12) intended to act on a surface of said at least one door to reduce the backlash between the surface and the fastening means and avoiding that the surface may be damaged while assembling and removing the fastening means.

Description

DESCRIPTION "Door locking device, particularly for sliding or swinging glass doors and the like." The present invention relates to door locking devices, particularly sliding glass doors (such as, for example, the sliding doors of display windows) or swinging doors and the like. The locking devices for display window sliding doors are known to comprise a lock unit and a serrated bar (i.e. having an edge provided with indents) comprising a U-shaped end to be fastened (by means of screws or glues) to a sliding inner door of the display window. The lock unit includes a mechanism, which can be controlled by a key, suitable to switch between open and closed configurations, and is provided with a through cavity for the serrated bar to be inserted therein, which also acts as a support for the lock unit itself.

^• When the locking device is in the closed configuration, the mechanism of the lock unit cooperates with an indent of the serrated bar thus preventing the unit from sliding which may cause the latter to slip off the serrated bar. In this configuration, and by properly adjusting the lock unit positioning, the other door (i.e. the one which is not secured to the bar) is caused to abut against the envelope of the lock unit such that both doors as a whole are prevented from sliding in both directions and thus the display window cannot be opened. In the open configuration (the lock mechanism does not cooperate with the indents on the serrated bar) , the lock unit can be caused to slide on the bar until slipping off the same, thus allowing both doors. to slide freely and the display window to be opened. Furthermore, locking devices of the padlock-type are known (typically used for sliding and/or swinging wings of gates or truck hatches) consisting of a lock unit (which can be controlled by means of a key) and two separate U-shaped portions each being secured to facing edges of a respective wing. In greater detail, the wing edges intended to be facing when the same are closed, are arranged in the inner cavity of the U-shaped portions, which are secured to the wings by means of through screws through each wing. Furthermore, to the U- shaped portions there are anchored respective support bases for knobs intended to be engaged with the mechanism of the lock unit. When the locking device is in the closed position, the lock unit is anchored to the knobs associated to both U-shaped elements such as to extend from one wing to the other thus preventing that they may move away from each another. In order to open the wings, act on the key, remove the lock unit from the knobs and then from the U-shaped portions, thereby releasing both wings. Both locking devices mentioned above have drawbacks concerning the fastening methods of the U-shaped portions to the respective door or wing, particularly in the case where the latter is made of glass or other fragile material. In fact, it has been noted that the U- shaped portion of the serrated bar of the locking devices for sliding display windows is such to damage the edge of the glass door fitted in the inner region thereof. This damage is made much more considerable due to the fact that the locking device requires to be frequently removed (for example, to clean the display window thoroughly) and subsequently mounted to the door, either in the same door region or a region other than that previously occupied. In the case of padlocks for wings, wherein the U- shaped portions are secured by means of screws, besides the consequent damaging of the wings, another drawback arises from the fact that this type of padlock cannot be easily removed and applied to other regions of the wing (for example, lower or higher on the wing) . Due to these reasons, the conventional locking devices of the "padlock" type cannot be applied to glass doors. The object of the present invention is to provide a locking device allowing to overcome the drawbacks of the above mentioned conventional devices . This object is achieved by a locking device such as defined in the annexed claim 1. Preferred embodiments of the invention are as defined in the dependent claims. The characteristics and the advantages of the present invention will be understood from the description below of one exemplary and non-limiting embodiment thereof in connection with the annexed figures, wherein: figure 1 is a perspective view of a first embodiment of a locking device in accordance with the present invention and in a non-assembled configuration; figures 2A and 2B are more perspective views of a lock unit and a rack bar of said device; figure 3 shows said locking device as being mounted to a pair of sliding doors; figure 4 is an exploded view of the lock unit of said device; figure 5 shows an example of a sprocket to be used in the lock unit of said device; figures 6A and 6B show two views of an exemplary stake used in the lock unit of said device; figure 7 is a perspective view of a second embodiment of a locking device of the invention in the disassembled configuration; figure 8 is a top view of said second embodiment in the assembled configuration; figure 9 shows the locking device in accordance with said second embodiment as being applied to two wings ; figure 10 is a perspective exploded view of the locking device in accordance with said second embodiment . With reference to figures 1, 2A, 2B, 3 and 4 a first preferred embodiment of a locking device 100 for doors in accordance with the present invention will be now described. Identical or similar elements and components will be referred to by the same numerals throughout the figures. Preferably, the locking device 100 of the invention is applied to the locking of sliding doors or sliding panels in the closed position. More preferably, the locking device 100 can be applied to glass doors used in display windows, glass showcases and similar. Particularly, for such first embodiment reference will be made to a display window including an inner door 101 and an outer door 102 (schematically shown in figure 3) sliding on each other along guides (not shown) . The locking device 100 comprises a bar 1 to be releasably fastened to the inner door 101 of the display window and a lock unit 2, which can be controlled by a key 20. In greater detail, the bar 1 comprises a portion 3, referred to as the elongate plate 3 in the following, i.e. a plate-shaped portion mainly extending lengthwise, having a substantially U-shaped fastening portion 4 at one of both ends thereof to fit engage with an edge 104 of the inner door 101. This elongated plate 3 comprises a major face 6 facing and parallel to a secondary face (not shown in the figures) and a side edge 5' joining the major face 6 with the secondary face. Furthermore, the elongate plate 3 can include guide ribs 5 projecting from the major face 6 to define a sliding region 7 on this face. The elongate plate 3 comprises a plurality of notches or recesses 8 arranged in the sliding region 7, such as to form a rack. Preferably, these notches 8 are equally spaced apart and the sliding region 7 is median relative to the guide ribs 5. Advantageously, the notches 8 are spaced apart from said side edge 5' i.e. in other words, they are formed only in the major face 6 and not in the side edge 5' . Preferably, the notches 8 are of the non-through type, and accordingly they do not form an aperture from the major 6 to the secondary faces. According to a particular embodiment, each notch 8 has a substantially semicircular plan and is internally shaped such as to comprise a stop wall 9 and an ascent wall 10, tilted relative to said stop wall 9. As will be made apparent below, each notch 8 is intended to house a suitable stake part of the lock unit 2. The fastening portion 4 of bar 1 comprises a wall 11 substantially parallel to the elongate plate 3 (though shorter than the latter) . It should be observed that this wall 11 is joined to plate 3 thus resulting one-piece with the latter. It should be observed that the bar 1 of the invention can be manufactured employing metal (for example iron) or plastic materials. Advantageously, this bar 1 is manufactured in a plastic material using nylon 6-6. Particularly, the slurry of the selected plastic material includes a percentage of glass fibre having the function of hardening and make the plastic material solid. For example, this percentage is 30%. The selected plastic material provides a lighter bar, and at the same time, prevents that the glass inner door 101 may be damaged while setting up the locking device 100. In addition, the fastening portion 4 presents a elastically yielding insert or locking element 12 at the wall 11 inner face. Particularly, this locking element 12 is arch-shaped with the ends thereof being fixed to the wall 11. Preferably, this element 12 is made of an elastic material, such as natural or synthetic rubber. Advantageously, the arch-shaped element 12 allows to lock the bar 1 by fastening it to the display window inner wall 101 and at the same time by adjusting it to glass doors of different thicknesses (for example, 4 to 8 mm thicknesses) without damaging them. Alternatively to the arch-shaped element 12 other suitable locking elastic means can be used (for example, hemispheric or cylindrical elements) . The lock unit 2 comprises a housing 13 containing the lock mechanisms 13 therein (shown in detail in figure 4) which can be operated by the key 20 between a closed position and an opened position. The housing 13 (having substantially the shape of a truncated cone in the example) comprises first 15 and second 16 inlet apertures. These apertures 15 and 16 are formed near a base edge 14 of housing 13 resulting in positions diametrally opposite to each other such as to be crossed by the bar 1. Particularly, it should be observed that the apertures 15 and 16 comprise a respective projection 17 (figure 2A) such as to be fitted to a complementary template of a cross-section of the elongate plate 3. Furthermore, at the first aperture 15, the housing 13 comprises a plane region 18 to receive in abutment a further edge 103 of the glass outer door 102 in the display window closed position. The outer surface of housing 13 advantageously includes two ergonomic notches 19 to facilitate a installer to grip the lock unit 2 and cause this unit to slide along bar 1. With reference to figure 4, there is depicted the mechanism 300 enclosed in the housing 13 of the lock unit 2. This mechanism 300 comprises a support unit 21, a sprocket 28 and a rotatable stake 31. The support unit 21 comprises a cylindrical body 22 orthogonal to a closing element 23 of the bottom of the housing 13 and connected as one-piece thereto. This closing element 23 comprises a passage or inserting and sliding duct 24 for the bar 1 to be inserted and slid therein. It should be observed that an inlet aperture (not seen in figure 4) and an outlet aperture 26 of duct 24 are shaped like the first 15 and second 16 through apertures of housing 13, respectively. Particularly, when the support element is inserted in the housing 13, the inlet and outlet apertures 26 are placed in front of the apertures 15 and 16, respectively. The cylindrical body 22 comprises an axial cavity 27 to house the cylindrical rotatable sprocket 28. This cavity extends all along the length of cylindrical body 22 thus resulting in communication with duct 24. The cylindrical body 22 comprises a first series of radial holes 29 opening inside the axial cavity 27. A second series of radial holes 30 is formed on the sprocket 28 such as to be aligned with the holes of the first series when the sprocket is in a first device-locking angular position. The lock unit is provided with a set of key lock components including: springs 40, pin or small upper stakes 41 (such as to house springs 40) and lower pins 42, intended to be suitably inserted in the radial holes 29 and 30 closed by respective caps 39. These components are known to those skilled in the art and are such to cooperate with the key talons 20 (appropriate for the lock) such as to translate vertically inside the radial holes 29 thus disengaging the holes 30 and allowing the sprocket 28 to rotate. The locks using this kind of opening and closing mechanism are known by those skilled in the art as the Yale-type locks. The sprocket 28 is shown in greater detail in figure 5 and the stake 31 is also shown in figures 6A and 6B. The sprocket 28 comprises a keyhole 32 for the key 20, provided in a head 55 of a substantially cylindrical body 56. At one end facing the head 55, the cylindrical body 56 is provided with tabs 35 suitable to transmit the rotary motion imparted by the key 20 to the stake 31. The stake 31 is provided with side seats 36 for the tabs 35 to be housed therein and a "sliced" end 50 intended to cooperate with the notches 8 of bar 1. A spring 34 of the helical type partially housed in a first cavity 37 formed in the sprocket 28 and partially in a second cavity 38 formed in the body of stake 31 is interposed between the sprocket 28 and the stake 31. The helical spring 34 is preloaded such as to affect the stake 31 and force it towards the active direction (such as indicated with an arrow F, in figure 4), i.e. in the direction of the notches 8 of bar 1. Furthermore, there is provided a stop tab 25 to be inserted in a suitable slot 43 of the cylindrical body 22 such as to lock the sprocket 28 to prevent the axial translation of the same . As may be better seen in figure 6A, the sliced end 50 of stake 31 has an outer surface 45, a first abutment or stop face 44, and a second face 33 tilted relative to axis A-A (rotation axis) of the stake (for example, about 30°) . By being controlled through the key 20, the stake 31 can be rotated by sprocket 28 between a closing position and an opening position. In the closing position, the stop face 44 of stake 31 is in abutment against the stop wall 9 of one of notches 8 of bar 1. In the opening position, the stake 31 is rotated such that the stop face 44 thereof does not face the stop wall 9 of notch 8 but is outside the notch and has a lower (and thinner) edge thereof 46 arranged laterally and externally to notches 8. In order to assemble the closing device 100, the U- shaped portion 4 of bar 1 is fastened to the edge 104 of the inner door 101. The elastically yielding locking element 12 allows to reduce the backlash between the edge of inner door 101 and the inner region of the fastening portion 4 in which the edge is inserted, thus ensuring a proper anchorage of bar 1 to the door 101. Furthermore, due to the characteristic of elastic yielding of the element 12 , it does not damage the door 101 but smoothly fits to the shape thereof. The lock unit 2 is fit on the bar 1 inserted in the sliding passage 24. In the open configuration, the lock unit 2 is free to slide along the elongate plate 3 of bar 1 in both directions such as to allow for a proper locking position to be selected. By acting on the key 20 to bring the device to the closed configuration, the stake 31 is rotated such that the stop face 44 thereof is in abutment against a stop wall 9 of a notch 8. In this condition, at least the lock unit 2 is prevented from sliding in the release direction to prevent that it may slip off the bar 1. It should be observed that the conformation of the ascent wall 10 of notches 8 allows the lock unit 2 to slide in the opposite direction to that of release (insertion direction) even when being in the closed configuration. In fact, the ascent wall is such as to be of no hindrance to the stake 31, which due to the action of the helical stake 34, moves axially by going in and out of the notches 8. Due to this sliding in' the insertion direction, the plane region 18 of lock unit 2 can be brought to abutment against the edge 103 of outer door 102 until locking the sliding of the same as well as the inner door 101, by closing and locking the display window. It should be observed that the particular conformation of the notches 8 (not provided as indents on the edge of bar 1 and, preferably, being non-through notches ) allows to prevent the stake 31 from coming in direct contact with the door 101 and damage it. Figures 7 to 10 refer to a locking device 200 made according to another embodiment of the present invention. Particularly, the locking device 200 is of the "padlock-type" and can be used to close wings or sliding or swinging doors 203 and 203', preferably made of glass. The padlock 200 comprises a respective lock unit or, more briefly, a lock 202 including, within an envelope, a corresponding (conventional per se and therefore not described) mechanism which can be operated by a key 220 to be inserted in the keyhole 220' . Furthermore, the padlock 200 comprises two respective portions or support frames of lock 202 having a substantially U-shaped transversal section such as frames 201 and 201' intended to mechanically cooperate with lock 202 and be fit engaged with outer edges of the doors 203 and 203', such as shown in figure 9. The support frames with U-shaped section 201 and 201' are identical to each other and, accordingly, only one of them will be described in detail below. The U-shaped section frame 201 has a semicircular plan, i.e. such as to be mechanically coupled with one half of lock 202 having a circular plan. Particularly, as shown in figure 10, the frame with U-shaped section 201' comprises an inner portion 270 and an outer portion 280. The inner portion 270 comprises two parallel facing walls 250 and 250' having a semicircular plan. These facing walls 250 and 250' are connected to each other at a respective rectilinear edge 262 by means of two joining walls 260 and 261 which result orthogonal to the facing walls. Furthermore, the facing walls 250 and 250' comprise at a semicircular edge, concentric ribs 271 and 272 defining a groove 273 housing a corresponding edge of lock 202. Each facing wall 250 and 250' comprises at least a through hole 215. Particularly, these walls 250 and 250' comprise a plurality of through holes 215 made at concave portions 232 of outer faces 231' and 231 (the latter not seen in figure 10) of walls 250' and 250, respectively. In greater detail, these concave portions 232 are shaped such as to house a complementary elastic insert 233. This insert 233 comprises a plurality of elastically yielding elements 212 (one for each hole 215) joined to one another. Preferably, the insert 233 and the elements 212 are made of an elastic material such as for example natural or synthetic rubber. Particularly, the elements 212 are shaped like spherical cap and are made of rubber. The outer portion 280 of the U-shaped section frame 201' comprises two covering walls 281 and 281' parallel to each other and orthogonal to a further joining wall 282. In accordance with figure 10, the outer portion 280 is shaped such as to be inserted, during an assembly step, on the inner portion 270 thus being fit coupled therewith. At least one of the covering walls 281 and 281' is provided of fastening elements 208 on an outer face thereof, which according to the example of the figures, are embodied in substantially mushroom-shaped knobs. The knobs 208 are intended to be engaged with the mechanism of lock 202 such as to allow the lock to be fixed to both U-shaped frames 201 and 201' . In an assembly configuration of the U-shaped frame 201' , at first, each insert 233 is positioned in the respective concave portion 232 such that each elastically yielding element 212 is inserted in the corresponding hole 215 and projects from inner faces 230 and 230' of walls 250 and 250'. Subsequently, the covering walls 281 and 281' of outer portion 280 are fit engaged between the concentric rib 272 and projecting portions of the joining walls 260 and 261 by covering in this manner the outer faces 231 and 231' of walls 250 and 250' and the respective inserts. Advantageously, the inner portion 270 of U-shaped frames 201 and 201' is made of plastic material such as 6-6 nylon. Furthermore, preferably, a percentage of glass fibre is added to the slurry of such material in order to harden and make this material solid. Advantageously, the outer portion 280 is manufactured from metal, for example, iron. Similarly to the locking elements 12 of the first embodiment, the elastically yielding elements 212 also allow to reduce the backlash between the frames with U- shaped section (201 and 201') and the corresponding wing (thus ensuring a good grip) and in the meantime, due to their relative softness they do not damage the wing. The provision of elastically yielding elements 212 allows to avoid the use of through holes in the wing and accordingly makes the locking device 200 suitable to be used for glass doors. To assemble the locking device 200 to the wings 203 and 203' of a glass door, the frames with U-shaped section 201 and 201' are fastened to a respective edge of each wing. This fastening (of the fit type) can be provided at different heights on the wing because the prearrangement of holes on the wings for the U-shaped frames to be univocally associated thereto is not required. When both doors 203 and 203' are being closed the substantially U-shaped frames 201 and 201' are placed in front of each other (particularly, their transversal walls 260, 261 face each other) . In order to lock the doors in the closed position, the lock 200 is coupled to the corresponding knobs 208 such that by extending from one door to another, it will hold the doors fixed in the closed position. It should be noted that, advantageously, the mushroom-shaped knobs 208 are arranged on both outer faces of the covering walls 281 and 281' of each U- shaped frame, thus allowing the lock 202 to be applied on both sides of the double-wing door to be closed. Advantageously, the padlock 200 can be applied to wings of glass doors having different thicknesses. For example, the glass wings can have thicknesses ranging between 8 and 12 mm. As already stated above, the teachings of the present invention allow to apply the locking device to glass doors (or made of a different material with fragile characteristics) preventing the doors to be damaged during the removal and subsequent assembly steps. Furthermore, the U-shaped portions provided with the elastically yielding locking elements (12 or 212) facilitate and speed up the assembly and the removal of the inventive device compared to the conventional devices using glues or screws, without compromising the efficiency of the lock. Obviously, to the locking device according to the present invention, those skilled in the art, aiming at satisfying contingent and specific requirements, will be able to carry out further modifications and variants, all being contemplated within the scope of protection of the invention, such as defined by the following claims.

Claims

Claims 1. Locking device (100; 200) of doors (101, 102; 203, 203'), particularly sliding or swinging glass doors and the like, comprising: - a lock unit (2; 202) to be controlled by a key (20; 220) such as to lock the doors in a closed position and unlock them to allow the relative motion thereof, - removable fastening , means (1; 201, 201') to at least one of the doors suitable to support the lock unit (2; 202) and mechanically cooperate with the same to lock the doors in said closed position, characterized in that said fastening means are provided with at least one elastically yielding element (12; 212) intended to act on a surface of said at least one of the doors to reduce a backlash between the surface and the fastening means and avoid damaging the surface during assembly and removal of the fastening means .

2. Device (100; 200) according to claim 1, wherein said at least one elastically yielding element (12; 212) is of an elastic material.

3. Device (100; 200) according to claim 1, wherein said at least one yielding element is of natural or synthetic rubber.

4. Device (100; 200) according to claim 1, wherein said fastening means have a portion (4; 201) having a substantially U-shaped section such as to be fit engaged with an edge of said at least one of the doors .

5. Device (100) according to claim 4, of the type intended to lock sliding doors, preferably for display windows wherein said fastening means comprise a bar (1) including an elongate plate (3) mainly extending in the longitudinal direction and provided at an end of the portion (4) with a substantially U-shaped section.

6. Device (100) according to claim 5, wherein the portion with substantially U-shaped section comprises a wall (11) substantially parallel to the elongate plate (3) , said at least one elastically yielding element (12) being arranged on an inner face of said parallel wall (11) .

7. Device (100) according to claim 6, wherein said at least one elastically yielding element (12) is arch- shaped with ends being fixed to the parallel wall (11) .

8. Device (100) according to claim 1, wherein said lock unit (2) comprises: - a lock mechanism (300) arranged in a housing (13) to be operatively associated to said key (20) , a moving stake (31) coupled to said lock mechanism intended to cooperate with the elongate plate (3) , the elongate plate (3) being inserted in through apertures (15, 16) formed in the lock unit such as to allow the lock unit to slide along the elongate plate.

9. Device according to claims 7 and 8, wherein said elongate plate (3) comprises: - a major face (6) and a secondary face opposite and parallel to the major face, - a side edge (5') joining the major face to the secondary face, - a plurality of notches (8) formed in said major face and being spaced apart from said side edge, said notches being intended to house the stake (31) at least partially to prevent the lock unit from sliding along the elongate plate in a disengagement direction of this unit from the elongate plate, and to allow locking the relative sliding of the sliding doors; in the closed position a door being fastened to said portion with a substantially U-shaped section of the bar and the other door being in abutment against a stop region of the housing.

10. Device (100) according to claim 9, wherein said plurality of notches is substantially aligned along a longitudinal direction as being defined by the elongate plate.

11. Device (100) according to claim 10, wherein said notches are of the non-through type.

12. Device (100) according to claim 10, wherein each notch (8) is internally shaped such as to comprise a stop wall (9) suitable to be brought to abutment against said stake (31) .

13. Device (100) according to claim 12, wherein each notch further comprises an ascent wall (10) which is tilted relative to said stop wall (9) and being such as to be of no hindrance to the stake during a sliding of the lock unit along the elongate plate in an opposite direction from that of disengagement.

14. Device (100) according to claim 8, wherein the lock mechanism comprises : a substantially cylindrical and rotatable sprocket (28) having a first end provided with a keyhole (32) for the key (20) and a second end mechanically coupled to said stake (31) to control the rotation thereof.

15. Device (100) according to claim 14, wherein said stake can be rotated by means of the sprocket in order to take: - a first position wherein it is at least partially inserted in a notch (8) of said plurality and has a respective stop face (44) in abutment against said stop wall (9) of the notch (8) , - a second position wherein the stake (31) is disengaged from the notch (8) such as to allow the lock unit (2) to slide along the elongate plate in said two directions.

16. Device (100) according to claim 15, wherein elastic means (34) are interposed between said sprocket

(28) and said stake (31) suitable to affect the stake (31) moving towards the notch (8) .

17. Device (100) according to claim 16, wherein while the lock unit (2) is sliding in said inserting direction, the elastic means (34) allow a translation motion of the stake to favour the engagement and disengagement of the stake in the notches.

18. Device (100) according to claim 9, wherein said elongate plate (3) has at least guide ribs (5) of the lock unit on one of said major (6) and secondary faces during the sliding on the elongate plate.

19. Device (100) according to claim 5, wherein said elongate shape (3) provided at an end of portion (4) with substantially U-shaped section is of a plastic material .

20. Device (200) according to claim 4, wherein said fastening means includes a further portion (201') with such a substantially U-shaped section to be fit engaged with a further edge of the other door.

21. Device (200) according to claim 20, wherein the portion and the further portion are placed in front to each other in the closing position of said doors.

22. Device (200) according to claim 20, wherein said lock unit (202) is intended to be fixed to said portion and to the further portion such as to extend from one door to the other thus holding the doors in the closed position.

23. Device (200) according to claim 20 wherein each of said portions with substantially U-shaped sections are provided with inner faces (230, 230') intended to face surfaces of the doors provided with said at least one elastically yielding element .

24. Device (200) according to claim 23, wherein each face of said portions with substantially U-shaped sections comprises a plurality of elastically yielding elements (212) .

25. Device (200) according to claim 20, wherein said at least one elastically yielding element is cap shaped, preferably made of rubber.

26. Device (200) according to claim 22, wherein said lock unit comprises a further lock mechanism to be operated by a respective key (220) and allows the lock unit to be secured to fixing elements (208) externally provided on said portions with substantially U-shaped sections.

27. Device (200) according to claim 20, wherein each substantially U-shaped portion (201, 201') comprises an inner portion (270) and an outer portion (280) .

28. Device (200) according to claim 27, wherein said inner portion (270) is of a plastic material and said outer portion (280) is of a metal material.