A CHAIR

Technical field

The present invention relates to chair seat mounts for providing attachment between seat and chair base. Specifically, the present invention relates to such mounts configured to providing for tilting movement of the seat relative to the seat base.

Background

Some chairs are designed to allow the seat to tilt relative to the base, to allow varying seating position. Some chairs are configured to be tiltable and locked in a number of discrete positions at different tilt angle. Discrete positioning gives a static seating position and requires cumbersome unlocking and locking operations to adjust the angle of tilting.

Thus, a tiltable chair allowing easy adjustment of tilting angle by movement of your own body mass, would be advantageous.

Some chairs are configured to be freely tiltable from a normal position to a back and/or a front position, with biasing means configured to force the seat towards its normal position. Typically, such chairs have a complex design with many moving parts, making them complex, heavy and expensive to produce. Further, the many moving parts often emit unwanted noise during rocking motion.

Summary

It is an object of the present invention to provide a joint for tiltably joining seat and base of a chair, wherein said joint contains few parts, is easy to manufacture, operates quietly and is continuously tiltable.

An aspect of the invention relates to an assembly for tiltably joining seat and base of a chair, wherein the assembly comprises a top member for attachment to the seat, and a bottom member for attachment to the base. The top member is arranged tiltably relative to the bottom member by means of at least two spacing means interposed between the top and bottom members. The spacing means are configured to define at least one axis of relative rotation between the top and bottom members. Further, the assembly comprises a resilient elastic means interposed between the top and bottom members and configured to be increasingly stressed when the top and bottom members are increasingly tilted relative to each other away from a normal position. The two spacing means act as a fulcrum or bearing enabling controlled and silent tilt movement. The resilient elastic means provides for dampened tilt movement, and the inner stress of the compressed or stretched resilient elastic means forces the joint back towards its normal position

The spacing means may comprise balls, wherein each ball is provided in respective recesses of the top and bottom members, and wherein each one of said at least one axis is defined by a respective linear arrangement of a plurality of said balls. The recesses control the position of the top and bottom members respectively, relative to the balls. Thereby, the position of the top and bottom members relative to each other is well defined.

A plurality of said balls may have substantially different elasticity modulus. The different elasticity modulus makes it possible to make an axis, around which the top and bottom plates tilt, movable in response to varying force on the balls along that axis. It is thus possible to easily change a ball to a ball with different elasticity, and thus affect the flexibility of the joint in several directions.

There may be provided a larger number of recesses for receiving the balls, than number of balls. The larger number of recesses makes it possible to move balls around, thus affecting movement

characteristics of the joint. For example, an axis of relative rotation may be moved relative to the top and bottom members by moving the balls between different recesses. Also, the number of axes may be increased or decreased by moving the balls between recesses. For three balls may be linearly arranged to define one axis, or they may be arranged in an L or triangle, thereby defining three alternative axes. Four balls may be linearly arranged to define one axis, or they may be arranged to form a square thereby defining parallel front and a back axes, each requiring different body position in front and back of seat to tilt around the respective axis, and together defining a more stable normal position. If one of the balls is elastic, it may be moved away from an axis to affect resistance of movement and dampening during tilt.

A connection means may be provided between the top and bottom members, wherein the connection means is attached to the top and bottom members such that the top and bottom members are tiltable relative to each other and prevented from moving away from each other more than a predetermined distance. The means thus allows tilt movement. It also prevents the top and bottom members from moving too far away from each other, thereby preventing the balls to move away from the recesses, and preventing the seat from falling off the base during tilting.

The connection means may be a member fixedly attached to either one of the top and bottom members, and having an end portion extending through a recess in the other one of the top and bottom members. The end portion is provided with a stop means large enough to prevent the stop means from passing though the recess, such as to prevent the top and bottom members from moving away from each other more than a predetermined distance. Such a connection means has a well-defined position on one of the top and bottom members, and thereby provides for easy assembly of the joint and reduces the number of separate components. The stop means ensures that the seat will not fall off the base.

The stop means may be axially adjustabe along the connection means. connection meansconnection means The axial adjustability makes it possible to adjust the amount of tilt by controlling how far from each other the top and bottom members may move.

The stop means may comprise a nut and corresponding thread on the connection means. This configuration provides for easy assembly of the joint by attachment of the nut to the connection means.

An end portion of the connection means may be provided with an axiosymmetric recess for receiving a matching axiosymmetric member of the base. The axiosymmetric recess thus enables the joint to rotate around an axiosymmetric member of the base, such as a vertical support axis. Another aspect of the invention relates to a chair comprising a seat, a base and an assembly according to any one of the preceding claims for joining the seat and the base. Such a chair contains few parts, is easy to manufacture and assemble, operates quietly and is

continuously tiltable.

The present invention will now be described in more detail, with reference to the appended drawings showing an embodiment of the invention.

Description of figures

Fig. l is an exploded view in top perspective of an assembly

according to an embodiment of the invention.

Fig. 2 is an exploded view in bottom perspective of the assembly also shown in Fig. 1.

Fig. 3 is a top perspective view of the assembly also shown in Fig. 1. Fig. 4 is a bottom perspective view of the assembly also shown in Fig. 1.

Fig. 5 is a top perspective view of the assembly also shown in Fig. 1 but with a resilient elastic material molded around the top and bottom plates.

Fig. 6 is a bottom perspective view of the assembly also shown in Fig. 5.

Detailed description

An assembly 1 according to a first embodiment of the invention is shown in Figs 1-4. The assembly 1 comprises a top plate 2 and a bottom plate 3. The top plate 2 comprises a central through circular recess 6 and is arranged tiltably relative to the bottom plate 3 by means of two balls 4 interposed between the top and bottom plates 2, 3. The balls 4 define an axis 9 of relative rotation between the top and bottom plates 2, 3. Each ball 4 is provided in a respective recess 5 of the top and bottom members 2, 3. The balls 4 act as fulcrums or bearings, depending on if the plates 2, 3 glide on the balls 4, which in turn depends on the diameter, materials and presence of lubricant. As shown in Figs 5-6, the assembly comprises resilient elastic composite material or rubber means 12 interposed between the top and bottom plates 2, 3, for example by injection molding as separate components, or injection molding directly over and into the assembly. When the top and bottom plates 2, 3 tilt, opposite end portions of the plates are brought closer to each other at one end of the assembly 1, and are brought away from each other at the other end of the assembly 1. A portion of the resilient elastic means 12 is compressed between the top and bottom plates 2, 3 as portions of the plates 2, 3 move closer to each other. Accordingly, a portion of the resilient elastic means 12 is stretched as portions of the plates 2, 3 are moved away from each other, since the resilient elastic means 12 is attached to the plates 2, 3. In other words, the resilient elastic means 12 is configured to be increasingly stressed when the members are increasingly tilted relative to each other away from a normal position. A substantially cylindrical connection means 7 is fixed centrally on the bottom plate 3. The connection means 7 extends through the central through recess 6 of the top plate 2. A locking member 8 is attached to a top end portion of the connection means 7 by means of a matching thread on the connection means 7 and the locking member 8. As shown in Figs 2 and 4, a bottom end portion of the connection means 7 is provided with an cylindrical recess 10 for receiving a matching cylindrical member of the base (not shown). The top and bottom plates 2, 3 are curved away from each other in order to provide for increased freedom of movement for tilting around the axis 9. Also, corners of the top plate 2 are provided with through holes 13 for enabling screws to secure the top plate 2 to the chair seat (not shown). The plates 2, 3 are preferably made of steel, and the balls 4 are preferably made of composite material. The resilient elastic member is preferably made of vulcanized rubber or composite material. The mentioned materials are examples, and other suitable materials may be used, without departing from the spirit of the invention.