WO1996008983A1

WO1996008983A1 - A piece of furniture having an adjustable seat

Info

Publication number: WO1996008983A1
Application number: PCT/DK1995/000379
Authority: WO
Inventors: Steen ØSTERGAARD
Original assignee: Oestergaard Steen
Priority date: 1994-09-23
Filing date: 1995-09-22
Publication date: 1996-03-28
Also published as: DK109494A; EP0789523A1

Abstract

A chair or a sofa has seating members, each of which comprises a back (4) and a foot rest (6) hinged to the rear edge (13) and the front edge (15), respectively, of a seat (5). The seating members are adjustable between a sitting position and a lying position, the back (4) and the foot rest (6) being so connected with the frame (7) of the article of furniture that the position of the foot rest (6) follows the back through displacement of the seat (5) and the frame (7) with respect to each other. In addition to said hinge connection (15) with the seat (5), the foot rest (6) is connected with the frame (7) of the article of furniture through a rigid push/pull connection (27) hinged at a distance from the hinge connection (15).

Description

A piece of furniture having an adjustable seat

The invention concerns an article of furniture, such as e.g. a chair, having a back and a foot rest hinged to the rear edge and the front edge, respectively, of a seat, said chair being adjustable between a sitting position and a lying position, said back and said foot rest being connected with the frame of the chair such that the posi- tion of the foot rest follows the back through displace¬ ment of the seat with respect to the frame.

Chairs of this type are known e.g. from US Patent Speci¬ fication No. 5 246 266. This patent discloses how the foot rest is caused to follow the position of the seat. For this purpose, the foot rest is provided with a pro¬ truding arm which extends along the side frame part of the foot rest, but forms an angle with the plane formed by the frame. The telescopic arm ensures that the pivot point of the telescopic arm on the frame of the chair is always positioned at a predetermined distance from the said plane of the foot rest, and the displacement of the hinge point of the foot rest thus pivots the foot rest plane about the pivot point on the chair frame. This technique has the drawback that the pivot point on the chair frame is located above the seat level, for which reason the telescopic arm is located externally on the seat and is thus visible. The principle of this US patent cannot be applied to a sofa either, where the individual seats are adjustable, if there are more than two seats. The reason is that it is just possible to establish a pivot point above the seat level when the seat concerned is not terminated by an arm rest or a dividing wall.

The object of the invention is therefore to provide an article of furniture having a connecting mechanism en- abling the foot rest to be moved in that the seat and the frame of the article of furniture are displaceable with respect to each other, which takes place in such a manner that the mechanism as a whole may be contained below the level of the chair seat.

This object is achieved by an article of furniture which is provided with a mechanism as defined in the character¬ izing portion of claim 1, there being provided between the foot rest and the frame of said article a rigid push/pull connection exerting a pull between the frame of said article and the foot rest, which results in a change in the position of the foot rest when the hinge point with the seat is displaced through displacement of the seat.

It is considerably more simple to provide a push/pull connection than a connection of the type disclosed by US Patent No. 5 246 266, as no great torsional forces will be applied to the frame of the foot rest in the area where the telescopic arm is secured.

Claim 2 states how the back may be hinged to the frame of the article of furniture, and since this hinging takes place at a distance from the hinge connection between the seat and the back, the latter hinge axis describes a movement along a circular arc when the position of the back is changed. It is hereby possible to construct the chair so that the rear edge of the seat rises when the back is lowered.

Claim 3 defines a special embodiment where the seat, at its front edge, is displaceable along a track in the frame of the article of furniture, whereby the front edge of the seat describes a linear movement when the seat is displaced. As the protruding pins of the seat are asymmetrical, pivoting of these pins by a suitable oper¬ ating mechanism ensures that the position of the chair is locked by the establishment of a frictional engagement. This embodiment involves a manually operated braking mechanism, which is deactivated and activated by operat¬ ing an operating knob.

Claim 4 also defines a braking mechanism, but this is provided at the rear end of the seat, and it is an auto- matic braking mechanism.

Claims 5 and 6 define special features of such an auto¬ matic braking mechanism, it being noted that this mecha¬ nism locks the position of the chair by retaining the po- sition of the hinge axis between the seat and the back. This locked state is released by moving the back in the opposite direction.

Claims 7 and 8 define features of an alternative embodi- ment of an automatic braking mechanism on an article of furniture of the invention, and the construction is sim¬ pler per se here, as the curved braking rod passes through an opening in the frame of said article having a cross-section corresponding to that of the braking rod, so that this opening serves both as a guide and as a stop for the braking mechanism.

Claim 9 states how toggle links may expediently be pro¬ vided between the foot rest and the seat so that these components together form a parallelogram. The push/pull connection is thus secured to the central portion on one of the sides of the parallelogram and thus determines the position of the parallelogram and thereby the position of the foot rest. Variation of the side lengths of the par- allelogram with respect to each other permits the trans¬ mission for the push/pull rod "travel" to be varied with respect to the foot rest. It should be noted for the sake of good order that the parallelogram is therefore not a mathematical parallelogram, as its sides are just ap¬ proximately of substantially the same length, so that more correctly the actual shape may be called trapezoi¬ dal.

The other end of the push/pull connection is preferably secured to the rear end of the frame of the article of furniture, i.e. in the vicinity of the hinge point of the back, so that the push/pull connection end hinged to the parallelogram follows a movement along a circular arc having a radius corresponding to the length of the push/pull connection. At the same time, at its front edge, the seat may be connected with the frame of the article of furniture through a swing arm, so that the front edge of the seat likewise describes a circular movement. As stated in claim 10, the length of the swing arm may advantageously be small with respect to the length of the push/pull connection, which in practice means less than half its length. Usually, the length of the swing arm constitutes between 10 and 30 % of the to¬ tal length of the push/pull connection, it being hereby ensured that the parallelogram connection has the desired effect.

The invention will be explained more fully below in con¬ nection with preferred embodiments and with reference to the drawing.

Fig. 1 is a lateral view of a preferred embodiment of a chair of the invention.

Fig. 2 is a sectional view of part of the frame structure of the chair shown in fig. 1. Fig. 3 is a section of the frame structure shown in fig. 1 for a chair of the invention in a sitting position.

Fig. 4 shows the parts shown in fig. 3 in the lying posi¬ tion of the chair.

Fig. 5 is a sectional view of part of the frame struc¬ ture, the chair of the invention being provided with a braking mechanism.

Fig. 6 is a cross-sectional view of the structure shown in fig. 5.

Fig. 7 is a sectional view of an alternative embodiment of a braking mechanism used in the chair of the inven¬ tion.

Fig. 8 is a cross-sectional view of the structure shown in fig. 7.

Fig. 9 is lateral sectional view of a third embodiment of a braking mechanism used in a chair of the invention.

The mechanism for moving the foot rest of the article of furniture is contained completely below the seat of the article, so that the mechanism may be used partly for one-seat chairs, partly for sofas having seats for two or more persons. Owing to the understanding of the inven¬ tion, it will be described below in connection with an armchair, but the described principle may also be applied in connection with multi-seat sofas and the like.

A chair of the invention is shown in fig. 1 and is gener¬ ally designated 1. The chair has a frame 2 which carries a seat 5, a back 4 and a foot rest 6. The term frame 2 is taken to mean the part of the chair which is in contact with the support and with respect to which the seat 5 is slidable. The frame 2 may optionally have an armrest 3.

It is shown in fig. 2 how the framework of the chair may be constructed, and it will be seen that there is a curved carrying rail 7 which is L-shaped or U-shaped in cross-section, i.e. the carrying rail has a longitudinal flange 7a, which essentially follows the shape of the seat 5 and is thus approximately horizontal, and a longi- tudinal flange 7b, which is essentially vertical. The carrying rail 7 is mounted on the frame 2 of the chair in a manner known per se, the mounting being selected in de¬ pendence on the structure of the frame or base part of the chair. Selectively, a central carrying rail 7 may be arranged below the centre of the chair, or a carrying rail may be provided at each side of the seat along its edge.

The back 4 has a rectangular framework in the form of a profiled tube frame 9 having welded thereto protruding arms 10 which form a pivotal connection with a corresponding, welded arm 8 on the rear edge of the carrying rail 7. The arms 8 and 10 are hinged by a through shaft 11 or stub shafts to provide the pivotal connection. Also the seat 5 has a profiled tube frame 12. The profiled tube frames 9 and 12 are hinged to each other through pivotal hinge links, the hinge arms being adapted to be received in hollow tube ends on the profiled tube frames 9 and 12. The hinge link 13 is preferably made of a plastics material of a suitable strength. Hollow, open tube ends 14 are provided at the front edge of the profiled tube frame 12 of the seat, receiving hinge links 15 corresponding to the hinge links 13. The other ends of the hinge links are received in corresponding hollow, open tube ends on a profiled tube frame which forms the framework of the foot rest. The transverse elements in the frames on the back, the seat and the foot rest are provided either by bending of the profiled tubes or by welding of transverse elements.

The profiled tube frame 12 of the seat is provided with downwardly extending, welded arms or pins 17 in the area around a welded cross brace at the front edge of the seat. The front edge of the seat is secured to the front edge of the carrying rail 7 through a pivotal link con- nection 18 by means of a through shaft 19 or stub shafts. This attachment takes place by means of a bolt 29.

Further, one end of a toggle link, generally designated 20, is mounted on the protruding arms or pins 17 by means of the through shaft 19. The toggle link consists of two links 21, 22 which are mutually pivotally connected by means of a hinge connection 23, e.g. in the form of a nut or tubular rivet. The other end of the link 22 is piv¬ otally connected with a protruding arm or pin 24 on the profiled tube frame 16 of the foot rest 6. This pivotal connection is likewise provided by means of a nut or tu¬ bular rivets 25.

A rigid push/pull connecting rod 27, whose one end is pivotally secured to a pivot 28 at the rear edge of the carrying rail 7, forms a pivotal connection with the link 21 approximately half-way between the two other pivots of this link.

The toggle link 20 will hereby assume a position which is positively controlled by the push/pull connecting rod 27, which will in turn adjust the foot rest to the de¬ sired position.

It is noted that when varying the length of the individ¬ ual link connections of the toggle link and the position of hinge points for the toggle link with respect to the seat and the foot rest, it is possible to vary the trans¬ mission of the mechanism which lifts the foot rest when the seat is displaced. It should be mentioned that the closer the push/pull rod hinge axis with the link 21 is to the hinge axis 19, the greater the transmission will be. To limit the size of the forces acting on the toggle link, the push/pull rod is usually secured to the centre of the link 21.

When the seat 5 and thus the profiled tube frame 12 of the seat are affected by a force in the direction indi¬ cated by the arrow A, the hinge link 13 will move about the shaft 11 in the direction indicated by the arrow B. This means that the back 4 and thus the profiled tube frame 9 swing in the direction indicated by the arrow C. As the front edge of the seat moves along a circular arc because of the link connection formed with the pivotal link 18, the shaft 19 moves along a circular arc about the bolt 29 in the direction indicated by the arrow B. The hinge axis between the link 21 and the connecting rod 27 moves about the attachment of the connecting rod 27 at the rear end of the profile rail and thus performs the movement indicated by the arrow E. This causes the axis of the hinge connection 23 to move in the direction indi¬ cated by the arrow F, which in turn moves the profiled tube frame 16 and thus the foot rest 6 in the direction indicated by the arrow G.

This is shown in detail in figs. 3 and 4. When the toggle link has been pivoted to the position shown in fig. 4, the foot rest can no longer be lowered by applying a force to the foot rest, as the toggle link 20 then forms a stretched connection in parallel with the hinge formed with the profiled tube frames 12 and 16. The toggle link 20 is provided with means (not shown) ensuring that the toggle link cannot be opened beyond a stretched connec¬ tion. When the chair is to be returned to the sitting po¬ sition, movement of the seat in a direction opposite to the force A causes a pull to be applied to the connecting rod 27, so that the toggle connection is again bent about the hinge connection 23.

Figs. 5 and 6 show a first embodiment of a braking mecha¬ nism for use in a chair or a similar article of furni- ture. Only the relevant part of the chair structure is shown in figs. 5 and 6, but it will be appreciated by a skilled person that such a braking mechanism can readily be incorporated in the structure shown in fig. 2. The braking mechanism comprises a braking rod 30 which is welded to a transverse element in the profiled tube frame 12 of the seat 5. The braking rod 30 hereby follows the movement of the seat when this is displaced. The braking rod 30 is received in a longitudinal slot 37 in the car¬ rying rail 7. The braking rod 30 is provided with two laterally protruding pins 31 which limit the travel of the braking rod. An inclined wall 34 is provided on the carrying wall 7 along the longitudinal slot 37, said wall defining, together with the braking rod 30, a wedge- shaped space between these parts. This wedge-shaped space accommodates a tube member 33 which is hinged at its one end about a shaft 35. A plate spring 32 biases this tube member toward the bottom of the wedge-shaped space. When, during the movement of the chair, the braking rod is moved toward the bottom of the wedge-shaped space, the tube member 33 ensures that frictional locking is estab¬ lished between the braking rod and the inclined wall, so that, when this movement is stopped, the chair will be retained in this position until the braking rod 30 is moved in the opposite direction. In one extreme position, the upper one of the pins 31 moreover ensures that this coupling is intensified, thereby maintaining the posi- tion. However, the braking rod is released by a reverse movement of the braking rod 30. The brake is an automatic brake which is controlled by the user by affecting the movable parts of the chair through displacement of his mass centre.

Figs. 7 and 8 show an alternative embodiment of an auto¬ matic braking mechanism. It will be seen that a braking rod 30 is likewise secured to a transverse element on the profiled tube frame 12 of the seat 5, but here this at¬ tachment takes place by means of a hinge connection 46 with a protruding pin 48 on this transverse element. Here, the braking rod has a curvature which corresponds to the hinge connection movement about the hinge axis 11 of the chair. The braking rod 40 is formed with two pins 41 and extends through an opening 47 in the carrying rail 7. By means of a stub shaft 45, a locking pin 43 is piv¬ otally mounted for engagement with the braking rod. The movability of the locking pin is limited by a leaf spring 42, which presses the locking pin down to engage the braking rod 40. When the braking rod 40 moves in a down¬ ward direction, the locking pin 43 acts as a wedge, the friction with the braking rod 40 trying to carry it along in the downward direction. However, the length of the braking pin 43 is adjusted such that the distance from the stub shaft 45 to the braking rod 40 is shorter than the locking pin length. The locking pin 43 will hereby be wedged against the braking rod 40, whereby friction be¬ tween the braking rod 40 and one side of the hole 47 pre- vents further movement of the braking rod. It will be seen that the upper one of the protruding pins 41 carries the locking pin 43 along in the downward movemen . When the locking pin 43 wedges the braking rod firmly against one wall in the hole 47, it takes a considerable force on the braking rod 40 in an upward direction to release the frictional coupling. This force is applied by the user by displacing his mass centre when he wishes to change his position in the chair.

Fig. 9 shows still another alternative embodiment of a braking mechanism for use in a chair of the invention, and in contrast to the two previous embodiments, the braking mechanism is manually operated here. In contrast to the two others, this braking mechanism is located at the front edge of the seat, the pivotal link connection 18 being here replaced by a guide track 51 positioned in the armrest of the chair frame. In contrast to the em¬ bodiment shown in fig. 2 where the front edge of the seat moves along a circular arc, the embodiment shown in fig. 9 means that the front edge of the seat moves along the linear track 51. The connecting link 18 is moreover re¬ placed by a downwardly extending arm 50 which is rigidly integrated with the profiled tube frame 12 by welding or the like, said arm being connected with an operating knob 54 via a rigid connection 55, which terminates in a pin 52 via an angled part extending through a hole in the arm 50. This pin is received in the guide track 51 and is asymmetrical, it being seen that one of the sides of the pin is ground plane. This ensures that the pin 52, when the operating knob 54 is pivoted away from the central position, is wedged in the guide track 51, thereby main¬ taining the position of the pin until the pin is released again by pivoting the operating knob to its central posi¬ tion. The chair structure shown in fig. 2 will hereby maintain its position as long as the brake is activated through the operating knob 54, and will be released only when the brake is deactivated through central positioning of the operating knob 54.

It is noted that the principle of guide tracks 51 with engaging pins 52 is useful as a substitute for the swing arm 18, even though the pins 52 do not form part of a braking mechanism.

The invention has been explained above in connection with a chair or the like, whose seat is displaceable with re¬ spect to the frame, but, clearly, the seat may be mounted stationarily with respect to the legs or the base of the chair. The frame will here be a part which connects back and foot rest, which requires a frame part extending sub- stantially in parallel with the seat.

Claims

P a t e n t C l a i m s :

1. An article of furniture having seating members, each comprising a back (4) and a foot rest (6) hinged to the rear edge (13) and the front edge (15), respectively, of a seat (5), the seating members of the article of furni¬ ture being adjustable between a sitting position and a lying position, the back (4) and the foot rest (6) being so connected with the frame (7) of the article of furni¬ ture that the position of the foot rest (6) follows the back (4) through displacement of the seat (5) and the frame (7) with respect to each other, said foot rest (6), in addition to said hinge connection (15) with the seat (5), being connected at the rear edge of the seat with an essentially stationary part of the article of furniture via a hinged, rigid push/pull connecting rod (17), c h a r a c t e r i z e d in that the push/pull connect¬ ing rod (17) is terminated in a toggle link (20, 21) which is arranged between the foot rest (6) and the seat (5) and whose ends are hinged to the frame (12, 16) of the seat (5) and the foot rest (6), respectively, at a distance from the hinge (15), and that the toggle link (20) is pivotally connected with said push/pull connect- ing rod (17) between its central hinge (23) and the hinge (19) on the seat frame (12).

2. An article of furniture according to claim 1, c h a r a c t e r i z e d in that the back (4) is piv- otally hinged to the frame (7) of the article of furni¬ ture, the hinge axis (11) between the back (4) and the frame (7) of the article of furniture being spaced from the hinge axis (13) located between the back (4) and the seat (5), so that the hinge axis (13) between the back (4) and the seat (5) moves along a circular arc upon movement of the back (4) .

3. An article of furniture according to claim 1 or 2, c h a r a c t e r i z e d in that the frame (7) of the article of furniture, at its front edge, is provided with guide tracks (51) facing the seat (5), that the seat (5) has protruding pins (52) to be received in said guide tracks (51) so that the pins are displaced along the tracks (51) when the seat (5) is displaced, that the pins (52) have a cross-section other than circular and a transverse dimension larger in one direction and smaller in another direction than the width of said tracks (51), and that the pins (52) are pivotable through an operating knob (54, 55) so that the displacement along the tracks (51) may be blocked through the frictional engagement es- tablished by the pivotal movement.

4. An article of furniture according to claim 1, c h a r a c t e r i z e d in that a braking rod (30; 40) is provided in the area around the hinge connection (13) between the back (4) and the seat (5), said braking rod being mounted on the seat (5) and being displaceable with respect to a stop on the frame (7) of the article of fur¬ niture, and that said article further includes a wedge element (33; 34) which forms a frictional coupling with the braking rod (30; 40).

5. An article of furniture according to claim 4, c h a r a c t e r i z e d in that the braking rod (30) is substantially rectilinear and has protruding pins (31) which serve as stops in the displacement of the braking rod.

6. An article of furniture according to claim 5, c h a r a c t e r i z e d in that the braking rod (30) is rigidly mounted with respect to the seat (5), that the stop of the article frame (7) comprises a slot (37) in which the braking rod (30) is received and moved by the displacement of the seat, and a stop wall (34) extending along the slot and forming an acute angle with the brak¬ ing rod (30), and that the wedge element (33) consists of a tube "member (33) which extends along the slot (37) and forms a frictional lock between the stop wall (34) and the braking rod (30), said lock being released by a pull in the braking rod (30).

7. An article of furniture according to claim 4, c h a r a c t e r i z e d in that the braking rod (40) is hinged to the rear edge of the seat and is formed with a curvature corresponding to the movement performed by the hinge axis (46) of the braking rod when the seat (5) is displaced as a consequence of the movement of the back (4).

8. An article of furniture according to claim 7, c h a r a c t e r i z e d in that the braking rod is provided with two protruding pins (41) limiting the travel of the braking rod (40) with respect to the ar¬ ticle frame stop, which is in the form of a passage (47) through which the braking¹ rod (40) extends, said opening (47) having a transverse dimension corresponding to the transverse dimension of the braking rod in the plane in which the braking rod (40) is located, and that the wedge element (43) comprises a pin mounted about an axis (45) in parallel with the hinge axis (46) of the braking rod, said pin having such a length that it is carried along by movement of the braking rod (40) in one direction and ex¬ erts a pressure on the braking rod (40) between the brak¬ ing rod hinge axis and engagement area with the stop.

9. An article of furniture according to claim 9, c h a r a c t e r i z e d in that the seat (5), at its front edge, is connected with the chair frame through a swing arm (18), the hinge axis (19) of the swing arm (18) describing a circular arc movement upon displacement of the seat (5), and that the length of the swing arm (18) is small with respect to the length of the rigid push/pull connecting rod (17).