Field of the Invention

The present invention relates to furniture for sitting, and more particularly to a seat module that can be used in a chair or where several modules can be assembled to form a seating row, as well as a tilting mechanism that is particularly suitable for use in such a seat module.

Backg round

So-called recltners are usually fitted with a control mechanism so that the angle of the backrest can be varied. The seat and backrest are usually hinged together while the backrest is pivotally attached to the armrests on each side. The user can then vary the angle of the backrest by pushing the body back and forth.

From Norwegian Patent 335401 it is known furniture for sitting where the position of the backrest and seat can be set in the same manner as in the recliners mentioned above. Here, however, the entire mechanism is hidden under the seat. A virtual turning point is established for the backrest so that the backrest does not have to be fixed to the armrests. The solution can therefore also be used in chairs without armrests, such as dining chairs.

There are also known office chairs where the backrest angle can be varied by turning a wheel or by operating a lever that unlock the backrest. With this solution, however, the backrest cannot be adjusted continuously as in the previous examples, as the backrest will return to the locked position when the user has finished the regulation. Such chairs may also have a tilt function that allows the backrest and seat to be tilted as a unit. This feature can also be locked.

Summary of the Invention It is an object of the present invention to provide a seat module for use in furniture for sitting that provides improved comfort for the user, is designed for rational production and can be used in several different items of furniture such as chairs and sofas or for interconnecting multiple seats in a row. Another object is to provide a tilting mechanism that is particularly suitable for use in the said seat module. This is achieved with a seat module and a tilting mechanism as set forth in the appended claims.

According to a first aspect of the invention there is provided a seat module for use in furniture for sitting, the seat module comprising a backrest, seat and coupling element, the coupling element comprising two side walls held together by transverse elements and further comprising rear grooves arranged at a rear end of the coupling element and front grooves disposed at a forward end of the coupling element, the rear and front grooves being disposed in respective sidewalls of the coupling element, the backrest being adapted to run along said rear groove, wherein a rear portion of the seat is connected to the backrest and wherein a front portion of the seat is adapted to run along said front groove. The seat module further comprises a tilting mechanism that connects the coupling element with a support member or base.

The background of this invention is that it is possible to use a backrest and seat adjustment mechanism where no locking mechanism is required, i.e., where the user can sit relaxed in any position of the seat module and at the same time be possible for the user to tilt the seat module, still without having to lock its position.

This provides a seat module where the user can immediately use the seat module and easily find an optimal seat position without having to figure out a system of levers etc. Another advantage of this construction is that both the setting function and the tilt function are handled by the coupling element underneath the seat, without the need for attachment to armrests or similar.

According to an embodiment of the invention, the backrest comprises brackets adapted to engage and run in said rear groove, the front portion of the seat being connected to a sliding unit running in said front groove, the rear grooves being provided as arcuate or radial incisions, wherein said brackets comprise

corresponding arcuate or radial projections adapted to engage the grooves on the coupling element and wherein the front grooves are provided as radial or arcuate or linear through grooves with a pitch toward the front of the seat module. This embodiment simplifies the mounting of the backrest on the coupling element.

According to a preferred embodiment, the coupling element comprises through openings located in the rear grooves and the seat module may comprise a locking rod adapted to pass through holes in the brackets and through said openings so that the backrest is locked to the coupling element.

Again, this is a solution that greatly simplifies the mounting of the backrest.

According to a further embodiment, said sliding unit includes sliding sleeves or lugs mounted at each end of a slide rod, the sliding sleeves or lugs being adapted to engage in said front groove.

Further, there may be arranged a spring between a transverse element in the coupling element and said slide rod.

According to an embodiment, the seat comprises rear recesses adapted to engage the locking rod and front recesses arranged to grip the slide bar.

This construction will greatly simplify the assembly of the seat module as the seat merely snaps into place on the coupling element. The spring has two functions as it ensures optimal balance in the sliding function and straightens the backrest when the user leaves the seat module. In case the seat module is used in a number of chairs that stand around a table or as elements in a sofa, the automatic

rearrangement of the backrest will ensure that the furniture always gives a clean impression. This solution for mounting the seat may also be used in other seat modules.

According to another aspect, the invention comprises a tilting mechanism comprising a central beam, which is multilateral in cross-section, elastic means surrounding the central beam and an outer housing surrounding the central beam and elastic means.

This tilting mechanism has a very simple construction, is very durable and can be easily maintained. The tilt mechanism may also be used in other seat modules, recliners, etc.

According to one embodiment, the outer housing comprises a U-shaped profile and a cover plate.

This solution provides a profile that can be included as a supporting element in a coupling element, and where the tilting mechanism is easy to mount. According to an alternative embodiment, the central beam comprises a conical hole for fastening a support frame and wherein an opening is provided in the outer housing for access to said conical hole.

Brief Description of the Drawings The invention will now be described in detail with reference to the accompanying drawings, in which :

Figures la and b are a side view of a chair incorporating a seat module according to the invention,

Figure 2 shows the individual elements included in the chair, in side view, Figure 3 is a perspective view showing the construction of the chair in more detail, and

Fig. 4 is a perspective view showing details of a tilting joint included in the invention.

Detailed Description In the following, directional indications such as "front", "rear", "upward",

"downward", "forward", "backward", "front", "downward projecting" etc., relate to a seat module in its natural position of use shown in the drawings.

Figures la and lb show a chair incorporating a seat module according to the invention comprising a backrest 1, a seat 2 and a coupling element 3 that holds the backrest and seat together, and further is attaching the backrest and the seat to a support member 4. Multiple seat modules, including backrests, seats and coupling elements, can be put together to form a sofa or a row of seat modules, instead of a chair as shown in the figure. Multiple seat modules can also be attached to a corner element so that they form a corner sofa and the like. Fig. la shows the chair with its back in upright position, while Fig. lb shows the chair when the back is angled backwards. The seat is also pushed slightly forward and the front of the seat is raised slightly in relation to the situation in Figure la. Fig. 2 shows the seat from the side, as the backrest and seat are loosened from the coupling element to show details of the structure. The coupling element comprises on its two respective sides rear grooves 7 and front grooves 9, the rear grooves being provided as arcuate or radial incisions. The backrest, in turn, comprises brackets 5 with arcuate or radial protrusions 6 adapted to engage the grooves 7 of the coupling element so that the protrusions can slide back and forth in the grooves 7. Thus, the grooves 7 define a turning point and an imaginary hinge point for the backrest 1.

The front grooves 9 are provided as correspondingly directed radial or arcuate through grooves, alternatively linear grooves with pitch toward the front of the seat module. Sliding sleeves or lugs 23 mounted on a slide rod 21 (Fig. 3) run in the grooves 9. The seat is secured to the slide rod by means of first notch 11 in the front lower part of the seat. The sliding sleeves or lugs 23 are mounted on each end of the slide rod 21, the sliding sleeves or lugs engaging respective front grooves 9 on either side of the coupling element 3.

Fig. 3 shows how the backrest is attached to the coupling element. The brackets 5 at the bottom of the backrest 1 are provided with arcuate projections 6, with the projections of the two brackets facing inwards and towards each other. The protrusions engage the rear grooves 7 and the backrest is locked to the coupling element by means of a locking rod 12 which passes through holes 22 at the end of each bracket and through longitudinal and through-openings 8 in the bottom of the grooves 7. The length of the openings 8 defines the rotational range of the backrest.

When assembling the seat, it is pressed down so that the front notches 11 grip around the slide rod 21. The slide rod 21 is secured with a spring 13 to a cross beam 14 which passes between the side walls of the coupling element 3. Similarly, at the rear end of the seat 2, rear notches 10 are arranged to grip the locking rod 12 (Fig. 2). By pushing the backrest 1 forward into the rear groove 7, the locking rod 12 will be pressed into and locked in the rear notches 10. The spring 13 serves to straighten the chair back when the user rises from the seat module. If there are more modules in a row, this will ensure a tidy impression when the modules are not in use. The spring has a strength adapted to balance the sliding function of the seat module, and also to ensure proper straightening of the backrest. When the seat is mounted, the spring will also have a bias. The coupling element 3 is preferably moulded as a single piece of fibre-reinforced plastic composite, although it can of course be manufactured in other suitable polymeric materials or metal, or partly of polymer and partly of metal. Likewise, both the backrest and seat can contain a core of composite or plastic covered with foam, fibre and fabric or skin. Alternatively, the said brackets may consist of metal cast in the backrest.

Figure 4 is an exploded view showing details of the tilt mechanism used in each seat module. The tilt mechanism comprises a central beam 15 which is polygonal in cross section. The central beam is terminated at each end by fixing plates 20. In this case the fixing plates are bolted to legs which form a support member or base 4. Around the central beam 15, there are elastic means 16. In the illustrated case, the beam with the elastic means is raised into a recess in the coupling element 3, the recess forming an opening in the U-shaped cross beam 14 (shown in Figure 3). The central beam is kept in place by closing the opening of the U-beam with a cover plate 17. The U-shaped cross beam and the cover plate thus form a housing around the central beam and the elastic means. The elastic means allow a rotational movement of the outer housing relative to the central beam. The central beam and cover plate preferably consist of metal, while the elastic means consists of parts manufactured in a suitable resilient material such as rubber or other type of polymer.

As mentioned above, the central beam is polygonal in cross section. From a production viewpoint, it is preferred that the beam be square or rectangular in cross section, but in principle it may have any polygonal shape. In the simplest case, it may be triangular in cross section, but it is also possible to use other shapes such as hexagonal, octagonal, etc.

In the case shown, the cover plate is attached with bolts (machine screws) 18 and nuts 19. Alternatively, the nuts can be replaced by a fixing plate located on top of the central beam, with threaded holes being provided in the fixing plate for the bolts 18. In yet another alternative embodiment, instead of through bolts, screws that engage holes in the coupling element are used.

In an alternative embodiment of the tilting mechanism (not shown) an opening is provided in the cover plate and a conical hole in the central beam. The opening is aligned facing the conical hole so that the tilt mechanism can easily be mounted on a chair base of the gas lift type. The tilting mechanism can in principle also be arranged in the opposite way, i.e. the central beam is attached or included in the coupling element and passes between the longitudinal walls thereof while the housing is attached to the base.

The tilting mechanism shown in Figure 4 is preferred for use in the shown seat module because it can easily be included as part of the coupling element. However, other types of tilting mechanisms may be used, for example a torsion spring tilting mechanism. Such tilting mechanisms are commonly used in office chairs. However, such a solution will readily comprise several components which must be bolted to the coupling element and a corresponding base complicating the mechanism. In use, the user can lean backwards and slide the seat forward. The backrest will then slide forward in the grooves arranged in the coupling element so that the back is angled backwards, Fig. lb, while the seat (which is coupled to the backrest) will be pushed forward along the front grooves of the coupling element. As the front tracks are arranged, the seat will also be raised slightly at the leading edge. Once the user has found his preferred position, the seat module setting is stable, even if the user should choose to flip back and forth via the tilting link between seat module and base.