SEAT RECLINER NECKANISX This invention relates to seat recliner mechanisms and reclining seats.
Various mechanisms have been proposed for seats, for example armchairs, in which the back support is movable between a relatively upright position and a reclined attitude.
Some of the proposed mechanisms have also included means for extending a leg rest as the back support is reclined.
The recliner mechanisms used up to now have been relatively complicated arrangements in an attempt to make the movement as effortless and smooth as possible.
Increasing complexity leads to increasing manufacturing costs.
When a seat is reclined there is a tendency for the user to feel he or she is going to slide off the front of the seat. To address this it is desirable to be able to lift the front of the seat relative to the rear to reassure the user that there is no danger of sliding off the front whether this is in fact the case or not.
It is an object of the present invention to provide a seat recliner mechanism that is relatively simple and yet easy to recline by a seat user.
According to the present invention there is provided a reclining seat mechanism comprising a base member, a back member arranged toward the rear of the base member, and a frame on which the base and back members are mounted, the back member being swingable between a substantially upright position and a relatively reclined position about a pivot point which is fixed relative to the frame, the rear of the base member being linked with the back member such that the back member, swinging about its pivot point, raises the front of the base member relative to the rear thereof as the back member is reclined.
The pivot about which the mechanism is swingable may be offset with respect to the centre of gravity of the back member, preferably forward of the back member when the back member is in the upright position. The pivot is preferably above and over the base member, the back member being connected with the pivot by a projecting arm projecting from one or both of the back and base members.
Preferably, the mechanism includes seat link means pivotably connected between, at one end, a point fixed relative to the frame and beneath the base member and, at the other end, with the base member, the seat link means being in an attitude inclined towards the rear of the base member when the seat is in the upright position, movement of the back member from the upright position moving the base member forwardly to raise it as the seat link means are moved toward an upright position.
The mechanism may include a leg rest member pivotably connected toward the front of the base portion or the frame. The leg rest member may be automatically extendable as the back member is reclined by means of leg rest link means connected, at one end, with a pivot on the back member below the pivotable connection with the base member and, at the other end, with the leg rest member.
A chair may comprise one mechanism according to the invention or one on either side. Arms for such a chair may be included in the mechanism by attaching them to the frame or to the base member.
The frame may include the chair legs or other structure supporting the chair.
The present invention can be put into practice in various ways, one of which will now be described by way of example with reference to the accompanying drawings in which :Fig. 1 is a side view of a reclining armchair mechanism according to the invention in an upright position;Fig. 2 is a side view of the mechanism of Fig.l in a semi-reclined attitude;Fig. 3 is a side view of the mechanism of Fig.l in a fully reclined position; andFigs. 4, 5 and 6 illustrate detail of a leg rest mechanism for use in the armchair of Fig.1.
Referring to Figures 1 to 3, a reclining armchair mechanism is illustrated side-on. It will be appreciated by the person skilled in the art that this embodiment of the mechanism constitutes the basic structure of the chair itself, requiring only suitable upholstery and covering to turn it into a usable armchair. The chair would usually have one of the mechanisms shown on either side. These would be mounted on a common box-like frame of which the side frame to be described below is one side. Similarly, the seat support and back panel are common to both mechanisms as is the leg rest and heel rest all of which will be described below.
The mechanism comprises a side frame 10 which has upper and lower spars 12 and 14 extending between forward and rear legs 16 and 18. A back panel 20 has a web 22 fixed to it by which the back panel is suspended from a pivot point 24 at the upper end of a web 26 mounted on and projecting above the upper spar 12. In the upright position of the back panel (Fig. 1) the web 22 projects forwardly.
The back panel 20 is pivotably connected, towards its base, with the rear of a seat support 28 to which is fixed a movable arm 30. Alternatively, the arm may be fixed to the upper spar so that the seat support moves relative to it.
A leg rest 32 is pivotably connected with the front of the seat support 28. There are two points about which the reclining mechanism acts which are fixed relative to the frame. The first is the pivot point 24 in the web 26 mentioned above. The second is a point 34 toward the forward end of the lower spar 14. A seat link 36 is pivotably connected to this second pivot point 34 which link is also pivotably connected with the seat support 28 at a point intermediate the front and rear seat support ends. In this embodiment the point is about 28% of the length of the seat support from the front of it, i.e. in the range between 20% and 40%, for example between 25% and 30% of the length.
The seat support 28 is thus suspended between the pivot toward the base of the back panel 20 and the upwardly projecting forward seat link 36. Starting from the upright position, as the back panel swings about its offset pivot 24 in the web 22, in the manner of a cradle, it describes an arc which causes it to lower the back of the seat. At the same time the movement of the reclining back panel pushes the seat support 28 forwardly. Because the seat is also suspended from the rearwardly inclined forward seat link 36, the front of the seat support 28 is raised relative to the frame as the forward seat link 36 rotates about its pivot point, which is fixed relative to the frame, towards an upright position. The arm of the chair on each side is directly connected with the seat support 28 and so moves with it during movement of the back panel 20.
A rear leg rest link 38 extends forwardly and beneath the seat support 28 and is pivotably connected with the back panel 20 below the pivotal attachment of the back panel with the rear of the seat support 28. This rear leg rest link 38 is also pivotably connected with a rear seat link 40 which is pivotably connected with a point on the seat support 28 about 30% of the length thereof from its rear end. One end of a forward leg rest link 42 is pivotably connected with a point on the rear seat link 40 below the rear leg rest link 36. The opposite end of the forward leg rest link 42 is pivotably connected with the leg rest 32 at a point about halfway between its pivotal connection with the seat support 28 and its free end.
Unlike the forward seat link 36 the rear seat link 40 is floating. In the upright position of the chair the rear seat link 40 is substantially upright. As the back panel 20 is reclined the lower end of the rear seat link is projected further forward than the upper end connected with the seat. Thus, when the back panel 20 is in an upright position, the leg rest 32 is also drawn into an upright attitude fully retracted next to the front of the frame 10. As the back panel 20 is reclined, the leg rest 36 rises with the forward end of the seat support 28 though the forward movement of the leg rest links 38 and 42 relative to the seat support 28. The movement of the lower part of the back panel 20 as it swings about its pivot also pushes the rising leg rest 32 outwardly so that it also rotates about its pivotal connection relative to the seat support 28.This movement caused by the forwardly moving lower part of the back panel 20 is relatively greater than the forward movement of the seat support 28 because of the changing attitude of the back panel 20.
Because the back panel 20 is arranged to swing about its pivot point which is offset forward of the back panel, it is able to extend the leg rest with the same movement that reclines the seat and raises the front of the seat relative to the rear. The ease of operation of the chair when it is being reclined is assisted by the tendency of the offset pivoted back panel to swing to an attitude closer to horizontal through the influence of gravity.
Figs. 4, 5 and 6 illustrate side sections of the leg rest mechanism. The end of the forward leg rest link 42 has a pivotal connection with a heel rest 48 which is slidably mounted within the hollow leg rest 32. The heel rest 48 is held retracted within the leg rest by a retaining spring (not shown). The forward leg rest link 42 also has a roller 52 which projects out of the side of the link 42 and is free when the mechanism is in the upright position. The radiused surface of a stop 50 is ridden over by the roller during intermediate movement of forward leg rest link 42. As the chair is reclined the advancing link 42 pushes the whole leg rest outwardly and upwardly because the heel rest 48 is initially retained in the retracted position by the retaining spring.As the leg rest rotates about its pivotal connection with the link 42 the roller 52 engages the radiused surface before the roller 52. This engagement prevents the heel rest 48 extending as the force against the spring becomes irresistible. The heel rest 48 is then released as the roller 52 move further into a detent 54 in the heel rest so that the heel rest is extended as the link 42 projects further with the reclining of the back panel. The connection of the heel rest with the pivot moves along a slot in the leg rest 32 as does the projection of the link 42 bearing the roller.
It will be appreciated by the skilled person that it is possible to provide spring or other biassing means to counter the gravity induced swing of the back panel about its pivot point. In this case, only a small effort on the part of the user will be required to recline the seat while allowing the biassing to return it to the upright position when the weight of the user's upper body is removed from the back panel. The biassing may for example be by means of a spring acting between the seat support and the back panel in the vicinity of the pivotable connection between them. Alternatively, or in addition, it is possible to attach a lever to, for example, the rear seat link that extends upwardly alongside the arm rest. This can be used by the sitter to alter the attitude of the back panel.
Similarly, the seat may have locking means so that it can be held in positions intermediate the upright and fully reclined. These are well known in the art and can easily be adapted for the present invention.
The invention has particular application to domestic armchairs, but is also equally applicable to other reclining seats, such as office chairs and aircraft seats.