BE1008253A6 - DEVICE FOR ADJUSTING AND LOCKING THE HEAD AND FOOT PARTS OF SLEEPING FURNITURE. - Google Patents

Abstract

Device for adjusting and blocking the head or foot parts of sleeping furniture using scissors formed by two elements crossing at a pivot pin, these elements each consisting of an upper arm and d '' a lower arm, among which the two upper arms are pivotally or pivotally and slidingly connected to the spar of the head or foot part and the two lower arms are pivotally or pivoting and slidingly connected to the opposite spar of the chassis and the upper arm of one of the elements and the lower arm of the other element are connected by a strut and a movable attachment piece on the lower arm, characterized in that the lower arm cooperating with the piece of hooking is a sliding rail (22) and the hooking part is produced in the form of a pinching part (41) sliding on the rail and capable of locking in any position tion.

Description

"Device for adjusting and blocking the head and foot parts of sleeping furniture"

The present invention relates to a device for adjusting and locking the head or foot parts of sleeping furniture using scissors formed by two elements crossing at a pivot pin, these elements consisting each time of an upper arm and a lower arm, among which the two upper arms are pivotally or pivotally and slidingly connected to the spar of the head or foot part and the two lower arms are pivotally or pivotally and slidingly connected to the opposite side member of the chassis and the upper arm of one of the elements and the lower arm of the other element are connected by a strut and a movable attachment piece on the lower arm.

Such a device is already known according to document DE-OS 1 654 383 which relates in particular to an adjustable support for adjusting the headboard part.

A special feature of this adjustable support is that the lower arm on which the attachment piece for the strut moves is a rack and the attachment piece is in the form of an adjustment slide. This adjustment slide cooperates with a switching pin fixed to the support blade, in particular with a star-shaped switching member inside a curve segment of the adjustment slide. The operation is such that at the first lifting of the head part, the support blade leaves the support position and passes into an idle position and during the second consecutive lifting, the support blade returns from the idle position to the desired support position. The head part must therefore be able to be lowered completely and no longer be placed in its highest position as in other systems.

The downside is the complicated and fragile construction. In addition, there is only one hooking per step. In addition, the bed dust gradually deteriorates the operation of the adjustment slide.

Unlike this, the object of the present invention is to simplify the device for adjusting and blocking the head and foot parts of sleeping furniture, bed-berths, or the like and for making this device to allow blocking in any which position.

To this end, the invention relates to a device corresponding to the type defined above, characterized in that the lower arm cooperating with the attachment part is a sliding rail and the attachment part is produced in the form of a pinch piece that slides on the rail and can be locked in any position.

This device avoids having to make teeth in the lower arms of the scissors. According to the invention, the pinching piece is simple and reliable.

A slide is certainly already known which allows the continuous locking of a rocking lever relative to a base rail, · it is applicable to tilting positioning devices used to tilt the head and foot parts of box springs and of office trays. The known slide is characterized in that on a base rail, with a pivoting, articulated lever, it is possible to move in both directions and to lock continuously by pressing on the tilting lever, by two opposite studs.

According to a first example of an embodiment of the known slide, this is made functional by a switching element which switches the pulling movement with the tilting lever articulated on the drawer from its exit position and thus puts the drawer in the position of pinching; upon encountering a predetermined stop, the slider and the resulting tilting movement straighten out and thus allow withdrawal of the slider and the tilting lever.

According to a second exemplary embodiment, the switching lever is made able to operate by a switching stud passed through a cavity of the side plates. A pulling movement with a tilting lever articulated on the drawer moves the rolling dowel on the base rail by rolling it back into the cavity. It then moves the slide from the basic position to the pinch position. When the slide is pulled against an intended stop, it tips forward. In this position, the switch stud moves by rolling back into the cavity forwards. This operation is reinforced by a weak branch spring, mounted. When the switch stud is in the front part of the cavity, it lets the slide back to its exit position with the rocking lever (DE-GM 77 04 457).

The two embodiments of the known drawer are very sensitive to dust and dirt. Their correct operation depends on a relatively low pivoting weight or on a switching stud. The two functional elements are exposed over time to bed dust. But in addition, the base rail must be mounted horizontally on the bed frame. The known drawer is therefore not suitable for devices using lifting scissors whose arms are placed in different inclined positions during their adjustment.

Contrary to this, the attachment piece according to the present invention is extremely simple and not very sensitive to incidents.

Thus: - the pinch piece consists of two pinch plates joined by an upper pinch pin and a lower pinch pin and an articulation pin, lower for the strut leaving an interval remaining.

- the pinch plates are triangular, the upper pinch stud is located above the slide rail and the lower pinch pin is located under the slide rail, and the lower hinge pin for the struts below the sliding rail is provided on the side of the nip facing the pivot pin of the lifting scissors.

- the upper pivot pin and the lower pivot pin, between the pinch plates, there is an upper and lower slide and pinch pad, these pads operating in the same way with respect to the upper and lower pinch edges of the rail sliding so that for a strut in traction, they are raised from the nip edges and that in the case of struts put under pressure, they are blocked with the nip edges.

The simple return of the gripping part to the rest position is ensured by an inverting slide.

Thus: - the sliding rail, between the clamping piece and the scissor hinge pin, there is an easily sliding reversing slider, with an attack arm directed towards the lower hinge pin of the strut on the nip for the lower hinge pin.

- one side of the sliding rail there are projecting stops for the reversing slide, among which, the upper stop located on the side of the scissor pivot pin, is located for the high position of the spar of the head part or foot, ensures the mounting of the lower stud of the strut on the attack surface of the arm and the lower stop which projects at the opposite end of the sliding rail ensures the separation between the lower articulation stud and the attack surface.

The reversing slide is of an extremely simple construction and therefore not very sensitive to incidents.

According to another advantageous characteristic of the invention, the arms or the arm and the sliding rail of the scissor elements pass equidistant from the center lines through the pivoting openings of the pivoting studs and are connected by an intermediate piece in at an angle to the midlines so that when the upper spar of the head or foot part is lowered there remains a safety gap between the scissor elements.

Thus, when the spar of the head or foot part is lowered, there remains a safety gap between the elements of the scissors.

According to another advantageous characteristic of the invention, at the free ends of the scissor elements, pivot pins have been fixed by means of which the lifting scissors are fixed to the fixing plates to the spar of the head part and of the part. chassis foot.

Thus, the free ends of the scissor elements are connected to the side members of the head part or of the foot part of the chassis.

According to another advantageous characteristic, each pivoting stud comprises a rivet end, a spacer ring and between these and an end cap, an intermediate zone of spherical shape, set back from the periphery of the spacer ring and end cap.

1 This embodiment of the pivot pins allows an articulated connection of the lifting scissors with the chassis or the head and foot parts.

According to another advantageous characteristic of the invention ·.

- each fixing plate consists of a screwing surface with, in an adjacent manner, a U-shaped zone, the free guide edge of which rests against the front face of the beam and the base surface of which is located a certain distance from the front face 1 has a slot whose width corresponds to the diameter of the spherical intermediate zone of the pivot pin.

- at least at one end of each slot there is a keyhole for passing the end cap of the pivot pin.

- one of the fixing plates is a small fixing plate with a short slot for fixing the pivot pin to the free only pivoting ends of the scissor elements.

- a safety clip provided behind the short slot of 1 the small fixing plate with a receiving housing for the end cap of the pivot pin.

These characteristics allow a simple assembly of the chassis and the head and foot part with the lifting scissors; they also allow easy attachment to the side members.

The invention thus creates a device for safe operation formed of simple elements for adjusting and blocking the head and foot parts of beds, sleeping furniture, berths, or the like and offers very high reliability.

An example of the invention will be described below in more detail with the aid of the appended drawings in which: - Figure 1 is an overall drawing of the device in the rest position and with the head or foot part raised, - Figure 2 is a view of the device of Figure 1 in the direction of arrow II, - Figure 3 is a side view of a pinch piece, - Figure 4 is a view along arrow IV of Figure 3 of the clamping piece - Figure 5 is a side view of a pinch pad, - Figure 6 is a view of the pinch pad in the direction of arrow VI according to Figure 5, - the Figure 7 is a side view of a reversing slide, - Figure 8 shows the reversing slide of Figure 7 seen in the direction of arrow VIII, - Figure 9 shows a small mounting plate.

- Figure 10 shows a large fixing plate, - Figure 11 shows a pivot pin, - Figure 12 shows a safety clip.

The device 1 is used to adjust and block the head or foot part of a sleeping unit using lifting scissors 9 composed of two elements 11, 19 which intersect at the level of a hinge pin 10.

The elements of the scissors each consist of an arm 14, 22, lower and an arm 12, 20 upper. The two upper arms 12, 20 are pivotally or pivotally and slidingly connected to the side member 2 of the foot or head portion. The two lower arms 14, 22 are pivotally or pivotally and tiltably connected to the opposite side member 6 of the chassis. In addition, the scissor arm 12 of one of the elements 11 and the lower scissor arm 22 of the other scissor element 19 cooperate by a strut 37 and by a hooking piece 41 movable on the arm of lower scissors 22.

The upper spar 2 of the head or foot part has a front face 3 and a lateral surface 4; correspondingly, the frame member 6 has a front face 7 and a side face 8.

The device 1 is shown in FIG. 1 with the scissors 9 in the lowered position and in the deployed position, - in this latter position, the beam 2 of the head or foot part is upright. The parts of the scissors 9, in the lowered position, are shown in solid lines while the parts of the lifting scissors 9 in the deployed position are shown in broken lines.

A scissor element 11 comprises an upper arm 12 and a lower lever 14. The free end 13 of the upper arm 12 is hingedly mounted in a manner described later on a small plate 56 for attachment to the upper spar 2 of the part head or foot. The free end 15 of the lower arm 14 cooperates in a manner described later with a large fixing plate 64, with the side member 6 of the chassis.

Correspondingly, the scissors element 19 consists of an upper arm 20 and a lower arm produced in the form of sliding rails 22.

The free end 21 of the upper arm 20 is hingedly connected to the large fixing plate 64 of the upper spar 2 of the head or foot part. The sliding rail 22 has a free end 27 which is hingedly connected by means of a small fixing plate 56 to the side member 6 of the chassis.

The element of the scissors 11 comprises an intermediate piece 16 which connects the upper arm 12 and the lower arm 14.

The element of the scissors 19 comprises an intermediate piece 2 8 connecting the upper arm 20 to the lower arm in the form of a sliding rail 22. Holes are provided for the hinge pin 10 in the intermediate parts 16 and 28. The dowel pin tilting 10 is crossed by the axis line 17 of the element 11 as well as by the axis line 29 of the scissors element 19.

The sliding rail 22 is provided with an upper gripping edge 23 as well as with a lower gripping edge 24, it comprises an upper stop 25 as well as a lower stop 26 whose function will be explained.

FIG. 1 clearly shows that when the scissors 9 are in the grouped state, there remains a pinch protection interval 31 between the arms of the scissors.

Between the upper arm 12 of the scissor element II and the sliding rail 22 is a strut 37. This is articulated to the upper arm 12 by an upper hinge pin 39 and by a deflection stud 38 lower than the pinch piece 41. The pinch piece 41 slides in a manner described later on the slide rail 22. In addition, an inversion slide 52 is slidably mounted on the slide rail 22; this slide 52 can slide between the stops 25 and 26 on the sliding rail 22.

Hinge connecting studs 32 are provided at the free ends 13, 21 and 27. According to FIG. 11, these studs consist of a rivet end 33 for fixing to the free ends, a spacer ring 34 and a spherical intermediate zone 35 as well as an end cap 36. The rivet end 33 of the connecting hinge pin 32 is engaged in a corresponding hole in the free end of the scissor arms to be shore. The fixing of the hinge pin 32 on the small fixing plate 56 or on the large fixing plate 64 on the side members 2 or 6 will be described later.

The pinch piece 41 which cooperates with the sliding rail 22 is shown in Figures 3 and 4. The pinch piece 41 consists of two pinch plates 42, 44 joined by a pinch pin 46 upper and a pinch pin 47 lower as well as by a lower hinge pin 38 for the strut 37. The distance between the pinching plates 41 and 42 is given the reference 45. This spacing is maintained by the sliding or pinching pads 48, 50, upper and lower provided on the upper and lower pinching studs 46, 47. The upper sliding or pinching pad 48 has a sliding or pinching surface 51 and the lower sliding or pinching pad 50 has a sliding or pinching surface pinch 49 upper. The gripping surfaces 49 and 51 are located opposite the upper or lower gripping edge 23, 24 of the sliding rails. When the support leg 37 is in traction, the gripping surfaces 49 and 51 are located a short distance from the gripping edges 23, 24 of the sliding rails. The pinching or attachment piece 41 can then move freely along the sliding rail 22.

When under pressure, the strut slightly rocks the pinching piece 41 so that the pinching surfaces 49, 51 of the pinching pads 48, 50 pinch the pinching edges 23, 24 of the sliding rails 22 securely.

The section according to FIG. 4 shows that the pinch plate 43 has an outwardly curved part 43 allowing the pinch piece 21 to pass the stops 25 and 26 at a lateral surface of the sliding rail 22 without being embarrassed.

The pinch plates 42 and 44 are fixed to the pinch pins 46 and 47 by means of fixing washers 40.

As shown above in Figure 3, the pinch plates 41 and 44 have a triangular shape. The upper pinch pin 46 is located above the slide rail and the lower pinch pin 47 is below the rail. The hinge pin 38, lower for the strut 37, is provided below the sliding rail 22 on the side of the nip 41 facing the hinge pin 10 of the lifting scissors 9.

Figure 1 shows that on the sliding rail 22, between the clamping piece 41 and the pivot pin 10 of the lifting scissors 9, there is an reversing slide 52 easy to slide. It has a leading arm 54 directed on the gripping piece 41 towards the lower hinge pin 38 of the strut 37. In the upper position, the lower hinge pin 38 for the strut 37 arrives on this attack arm.

In detail, FIG. 1 shows that when the upper spar 2 of the head or foot part occupies the lower position, the reversing slide 52 is applied by its inclined, straight edge, shown in FIG. 1, against the lower stop 26 on the sliding rail 22. When the upper spar 2 of the upper head or foot part is raised, the strut 37 pulls the clamping piece 41 to the left and the reversing slide 52 is driven to the left. At the end of the upward movement of the upper spar 2, the traction exerted on the pinch piece 41 ends and due to the weight of the foot or head part, which is transmitted to the pinch piece 41 by the leg force 37, the latter locks slightly so that the gripping surfaces 49 and 51 of the gripping pads 48 and 50 are applied firmly against the gripping edges 23, 24 of the sliding rails 22. The head or foot locks in the desired position.

At the first raising of the beam 2 and for the rest of the movement of the head or foot part towards the upper position, the reversing slide 52 arrives with its diagonal edge, left shown in FIG. 1, against the upper stop 25 then the articulation pin 30, lower, arrives on the attack surface 55 of the attack arm 54 on the reversing slide 52. The pinching piece 41 thus swings, which allows it to return to the rest position because in each position, the sliding or gripping pads 48, 50 cannot make their sliding or gripping surface 49, 51 cooperate with the gripping edges 23, 24 of the sliding rails 22. As in the lower position, the inclined edge, shown at right in FIG. 1 for the reversing slide 52, meets the lower stop 26, the stop stud 38, lower, separates again from the attack surface 55 of the attack arm 54 on the reversing slide 52. Cn canthen raise the side member 2 again as indicated above.

Figures 7 and 8 show that the reversing slide 52 is formed of a sliding frame 53 preferably made of a suitable plastic.

To articulate the pivot studs 32 on the side members 2 and 6 of the head part and of the foot part or of the chassis or frame, fixing plates 56, 64 shown in FIGS. 9 and 10 are provided. attachment 56 or 64 is formed by a screwing surface 57, 65 to which a U-shaped area 58, 66 is connected. The U-shaped areas 58, 66 have free longitudinal edges 59, 68 which are supported against the front faces 3, 7 of the side members 2, 6. Each fixing plate 56, 64 has, at a certain distance, front faces 3, 7 of the side members 2, 6, base surfaces 60, 67 each provided with a slot 61, 69. The width 62, 70 of the slots corresponds to the diameter of the spherical intermediate zone 35 of the hinge pin 32.

At at least one end of each slot 61, 69 there is a keyhole 63, 71 for passing the end cap 36 over a tilting stud 32.

As shown in Figures 9 and 10, there is a small fixing plate 56 and a large fixing plate 64. Figure 9 shows the small fixing plate 56 with the short slot 61 for fixing the pivot pin 32 only at the ends free in pivoting 13, 27 of the scissor element 11, 19. Behind the short slot 61 of the small fixing plate 56 there is a safety clip 72 shown in FIG. 12 with an opening 75 to receive the cap. end 36 of the pivoting connecting stud 32. In detail, the safety clip consists of a rectangular frame 73 with a covering surface 74, lowered, with in the middle zone, the receiving opening 75 surrounded for the end cap 36 of the tilting stud 32. The safety clip 72 is introduced between the front face 3, 7 of the side members 2, 6 and the base surface 60 of the U-shaped area 58 of the small fixing plate 56. The small plate ue of attachment 56 is guided using screws (not shown) which pass through the screwing surface 57, to the spar 2, 6. The longitudinal edge 59, free, then applies against the front face 3, 7 of the spar 2, 6.

To allow both tilting and translation of the free ends 13, 21 of the lower arms 14 and of the upper arms 20 relative to the side members 2, 6, the other fixing plate is a large fixing plate 64 with a longitudinal slot 69 for guiding the pivot pin 32. According to FIG. 10, the large fixing plate 64 also has a screwing surface 65 as well as a U-shaped zone 66 whose free longitudinal edge 68 is applied against the front surface of the respective spar. The long slot 69 is formed in the base surface 67 of the large fixing plate 64. The long slot 69 is also provided with at least one keyhole 71 at its end. The width 70 of the long slot 69 corresponds to the diameter of the spherical intermediate zone 35 on the pivot pin 32. The long slot 69 has a length such that when adjusting the head or foot part, it can receive the pin pivoting 32 without the latter escaping from one of the keyholes 71.

The reversing slide 52 shown in FIGS. 7 and 8 consists of a sliding frame 53 made of plastic to receive the sliding rail 22. The lateral edges of the sliding frame 53 are inclined at an angle of 25 ° relative to the sliding rail 22. The attack arm 54 has a slightly rising attack surface 55 for the lower hinge pin 38 of the strut 37 on the clamping piece 41.

LIST OF REFERENCES

1. device 26. lower stop 2. upper spar of 27. free end of the head part or of 28. center line foot 30.

3. front face 31. protective distance 4. lateral surface against pinching 5. ment 6. chassis beam 32. articulation stud 7. front face 33. rivet end 8. lateral surface 34. ring 'spacing 9. lifting scissors 35. intermediate zone 10. spherical hinge pin 11. scissor element 36. end cap 12. upper arm 37. strut 13. free end 38. hinge pin 14. lower lower arm 15. free end 39. hinge pin 16. upper intermediate piece 17. center line 40. washer or ring for 18. fixing 19. scissor element 41. pinch piece 20. upper branch of 42. scissor pinch plate 43. curved part 21. free end 44. pinch plate 22. slide rail 45. spacing 23. pinch edge su- 46. upper pinch pin stud 24. pinch edge in- 47. lower pinch pin stud 25. upper stopper 48. upper slide or pinch pad 49 sliding pad 74. upper covering or pinching surface 75. Housing 50. lower sliding or pinching pad 51. lower sliding or pinching surface 52. reversing slide 53. sliding frame 54. d arm 55. attack surface 56. small fixing plate 57. screwing surface

58. U-shaped area

59. free longitudinal edge 60. base surface 61. short slot 62. width 63. keyhole 64. large fixing plate 65. screwing surface

66. U-shaped area

67. base surface 68. free longitudinal edge 69. long slot 70. width 71. keyhole 72. security clip 73. rectangular frame

Claims (5)

1 °) Device for adjusting and blocking the head or foot parts of sleeping furniture using scissors formed by two elements crossing at a pivot pin, these elements consisting each time of a upper arm and a lower arm, of which the two upper arms are pivotally or pivotally and slidingly connected to the spar of the head or foot part and the two lower arms are pivotally or pivotally and slidingly connected to the spar opposite of the chassis and the upper arm of one of the elements and the lower arm of the other element are connected by a strut and a movable attachment piece on the lower arm, characterized in that the lower arm cooperating with the attachment part is a sliding rail (22) and the attachment part is produced in the form of a pinching part (41) sliding on the rail and capable of locking in any position. 2 °) Device according to claim 1, characterized in that the clamping part (41) consists of two clamping plates (42, 44) joined by an upper pinching pin (46) and a lower pinching pin (47 ) and a hinge pin (38), lower for the strut (37) leaving a gap (45). 3 °) Device according to one of claims 1 and 2, characterized in that the pinch plates (41, 44) are triangular, the pinch pin (46) upper is located above the slide rail (22) and the lower pinch pin (47) is located under the slide rail, and the lower articulation pin (38) for the struts (37) below the slide rail (22) is provided on the side of the pinch piece (41) facing the pivot pin (10) of the lifting scissors (9). 4 °) Device according to claim 3, characterized in that on the upper pivot pin and the lower pivot pin (46, 47), between the pinch plates (42, 44), there is a sliding pad and pinch (48, 51) upper and lower, these pads operating in the same way with respect to the upper and lower pinch edges (23, 24) of the sliding rail (22) so that for a strut (37) in traction, they are raised from the nip edges (23, 24) and in the event of struts (37) pressurized, they are blocked with the nip edges (23, 24). 5 °) Device according to one of claims 1 to 4, characterized in that on the sliding rail (22), between the clamping piece (41) and the hinge pin (10) of the lifting scissors (9 ), there is an easily sliding reversing slide (52), with a leading arm (54) directed towards the lower articulation pin (38) of the strut (37) on the clamping piece (41) for the lower hinge pin (38). 6th) Device according to one of claims l to 5, characterized in that on one side of the sliding rail (22) there are stops (25, 26) projecting for the reversing slide (52), from of which, the upper stop (25) located on the side of the pivot pin (10) of the lifting scissors (9), in the high position of the beam (2) of the head or foot part, ensures the raising of the lower pin (38) of the strut (37) on the attack surface (55) of the arm (54) and the lower stop (26) which projects at the opposite end from the sliding rail (22) ensures the separation between the lower hinge pin (38) and the attack surface (55). 7 °) Device according to one of claims 1 to 6, characterized in that the arms (12, 14) or the arm (20) and the sliding rail (22) of the elements (11, 19) of the scissors pass from equidistant from the center lines (17, 29) by the pivoting openings of the pivot pins (10) and are connected by an intermediate piece (16, 28) at an angle to the center lines (17, 29) so that when the upper spar (2) of the head or foot part is lowered there remains a safety gap (31) between the elements (11, 19) of the scissors. 8e) Device according to one of claims 1 to 7, characterized in that at the free ends (13, 15, 21, 27) of the scissor elements (11, 19) pivot pins (32) are fixed to by means of which the lifting scissors (9) are fixed to the fixing plates (56, 64) to the beam (2, 6) of the head part and the foot part of the chassis. 9 °) Device according to claim 8, characterized in that each pivot pin (32) has a rivet end (33), a spacer ring (34) and between these and an end cap (36 ), an intermediate zone of spherical shape, set back, with respect to the periphery of the spacer ring (34) and the end cap (36). 10 °) Device according to one of claims 1 to 9, characterized in that each fixing plate (56, 64) consists of a screwing surface (57, 65) with, adjacent to, a zone (58 , 66) U-shaped, whose free guide edge (59, 68) is applied against the front face (3, 7) of the beam (2, 6) and whose base surface (60, 67) located at a certain distance from the front face (3, 7) has a slot (61, 69) whose width (62, 70) corresponds to the diameter of the spherical intermediate zone (35) of the pivot pin (32). 11 °) Device according to claim 10, characterized in that at least at one end of each slot (61, 69) is a keyhole (63, 71) for passing the end cap (36) of the stud pivot (32). 12 °) Device according to claim 10 and 11, characterized in that one of the fixing plates is a small fixing plate (56) with a slot (61), short, for fixing the pivot pin (32) to free only pivoting ends (13, 27) of the scissor elements (il, 19). 13 °) Device according to claim 12, characterized by a safety clip (72) provided behind the short slot (61) of the small fixing plate (56) with a receiving housing (75) for the end cap ( 36) of the pivot pin (32). 14 °) Device according to claim 13, characterized in that the safety clip (72) consists of a rectangular frame (73) with a lowered upper surface (74) and whose middle zone includes the receiving orifice ( 75) surrounded for the end cap (36) of the pivot pin (32). 15 °) Device according to claim 11, characterized in that the other fixing plate is a large fixing plate (64) with a long slot (69) for guiding the pivot pin (32) at the free ends (15, 21) longitudinally sliding and pivoting elements (11, 19) of the scissors. 16 °) Device according to claim 5, characterized in that the reversing slide (52) consists of a plastic sliding frame (53) for receiving the sliding rail (22), the lateral edges of the frame of the slide made of plastic (53) at an angle of approximately 15 ° relative to the sliding rail (22) and the attack arm (54) and its slightly rising attack surface (55) for the lower articulation pin ( 38) of the strut (37) is provided on the clamping piece (41). 17 °) Device according to one of claims 1 to 16, characterized in that the elements (11, 19) of the scissors (up to the sliding rail (22)) are made of profiled sheet. 18 °) Device according to one of claims 1 to 17, characterized in that the pinching studs (46, 47) receiving the pinching pads (48, 50) are fixed outside the pinching plates (42, 44) of the clamping piece (41) using fixing rings (40). 19 °) Device according to claim 6, characterized in that one of the clamping plates (42) of the clamping piece (41) has a curved portion (43) to pass over the stop (26) projecting on one side of the sliding rail (22) for the reversing slide (52).