GB2304279A - Folding chair - Google Patents

Abstract

A folding chair having a concertinaing seat portion 10 and a concertinaing backrest portion 11 mounted upon a framework consisting of two collapsible side frames connected by collapsible X-brace mechanisms 38,42,70. Each side frame comprises a collapsible lattice portion 16 and a rear leg 17 pivotally mounted near the upper end thereof to the lattice portion. On each side frame a centrally hinged bracing device 30 is pivotally connected at the ends 31,32 thereof to the seat support 19 and rear leg 17 respectively. A tie-rod 33 actuates the bracing device when the backrest is moved relative to the rear leg. The seat portion 10 and backrest portion 11 have included in their construction spring devices which compel them to a folded status. The X-brace mechanisms connect the side frames via pivotal joints which enable the side frames and X-brace mechanisms to collapse in unison.

Description

FOLDING CHAIR.

This invention relates to a folding chair.

The directors chair is a well known type of folding chair typically comprising a canvas seat and backrest mounted upon a robust wooden framework. The seat and backrest are mounted between supporting members at the sides of the framework; a configuration which results in the high level of comfort for which the directors chair is noted. The design and construction of the framework does, however, make the directors chair significantly larger when folded and heavier than many other types of folding chair.

The present invention seeks to provide a folding chair in which it is possible to combine the comfort characteristic of a directors chair with a more lightweight and compact folding framework.

According to the present invention there is provided a folding chair having a concertinaing seat portion, a concertinaing backrest portion and means for releasably securing the chair in a deployed status mounted upon a framework comprising two similar side frames connected by a collapsible X-brace arrangement, each side frame having a foreleg, seat support, backrest support and armrest formed by constituent members of a collapsible lattice portion which is supported by a rear leg pivotally mounted at the upper end thereof to the lattice portion at the juncture of the seat support and backrest support, the lattice portion being collapsible in unison with the X-brace arrangement.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawing in which: Figure 1 is an isometric front view of the chair in a deployed status.

Figure 2 is an isometric scrap view of the rear of the chair showing the upper rear X-brace mechanism and concertinaing backrest portion in a deployed status.

Figure 3 is a rear view of the rear legs and lower rear X-brace mechanism in a deployed status.

Figures 4, 5 & 6 show the framework in side elevation and combine in series to show the action of the side frames as the chair is deployed.

Figure 7 is a perspective scrap view on an enlarged scale and shows the slidable connection of the lower rear X-brace mechanism to a rear leg.

Figure 8 is a perspective scrap view on an enlarged scale showing the connection of one constituent member of the front X-brace mechanism to a lattice portion via a U-shaped bracket.

Figure 9 is an isometric view of the rubber spring device.

Figure 10 is an isometric scrap view showing part of the seat portion in a semi-deployed status.

Figures 11 & 12 show in plan view the front X-brace mechanism in folded and expanded positions respectively and combine to illustrate the expanding action of the brace as the chair is deployed.

Referring to the drawing, the chair has a folding seat portion 10 and a folding backrest portion 11 mounted upon a framework consisting of two folding side frames connected by three collapsible X-brace mechanisms. Each side frame is constructed in mirror symmetry to the other, each comprising a collapsible lattice portion 16 and a supporting rear leg 17 which is adapted to act as a partial cover when the chair is in a folded status. A foreleg 18, seat support 19, backrest support 20 and armrest 21 are formed by constituent members of the collapsible lattice portion wherein each constituent member is reinforced by a duplicate member connected in parallel spacedapart relation to its twin. The rear leg is pivotally mounted at the upper end thereof to the lattice portion at the juncture of the seat support and backrest support.

A centrally hinged bracing device 30 is pivotally mounted at the ends 31,32 thereof to the seat support and rear leg respectively. A tie rod 33 is pivotally connected at the lower and upper ends thereof to the bracing device 30 at the lowest centrally hinged point thereof and the backrest support respectively.

Each collapsible X-brace mechanism has four elongate members pivotally connected to form a double X pattern.

Each lattice portion has pivotally mounted on the inner side thereof a first U-shaped bracket 34 at the juncture of the seat support and foreleg, and a second U-shaped bracket 35 at the juncture of the armrest support 36 and lower connecting member 37. The front X-brace mechanism 38 has the outermost end of each elongate member pivotally connected to a U-shaped bracket as shown in figure 8, the elongate member being able to move angularly in the direction of the arrow 40 while the U-shaped bracket rotates in the direction indicated by the arrow 41.

The front X-brace mechanism 38 and upper rear X-brace mechanism 70 are substantially similar in construction.

The lower rear X-brace mechanism 42 has each of its two upper outermost ends 60,61 pivotally connected to a respective rear leg near the upper end thereof. Each rear leg has near its lower end a vertical slot 45, the rear brace 42 having each of its two lower outermost ends 43,44 slidably connected to a respective rear leg by means of a pivotal connection made through the slot, as illustrated in figure 7.

A centrally hinged brace 48 with over-centre locking capability is mounted at the centre of the rear bracing mechanism 42, each end of the hinged brace 48 being pivotally mounted at the centre of an X, as shown in figure 3.

The folding seat 10 is constructed from a flexible material such as canvas and has bonded to the underside thereof a spring device 53. Shown in figure 9, the spring device 53 is moulded in the form of a tight zig-zag from a resilient elastic material such as rubber or polyurethane and is therefore compelled to return to its original moulded form when stretched, twisted or otherwise deformed.

The seat 10 and backrest 11 are of similar construction.

In order to deploy the folding chair for use each backrest support 20 is drawn away from its respective rear leg 17 as shown in figure 4 in the direction of the arrow 23.

The X-brace mechanisms 38,70,42 ensure that the two side frames act in unison during deployment.

Referring to figures 4,5 & 6, each side frame acts as follows: As the backrest support is drawn away from the rear leg the tie rod 33 draws the extended centrally hinged bracing device 30 inward in the direction of the arrow 54, causing the two ends 31,32 of the bracing device 30 to move apart and thus the seat support to move away from the rear leg in the direction of the arrow 56. The geometry of the bracing device 30 and tie rod 33 arrangement ensures that the foreleg 18 and rear leg 17 do not clash as the chair is deployed. When the side frame reaches a fully deployed status a stop 27 mounted on the upper end of the rear leg 17 contacts the backrest support preventing further angular movement thereof.

As can be seen in figures 4,5 & 6 the distance between the two U-shaped brackets 34,35 decreases as the side frame is deployed. The two outer ends 57,58 on each side of the front bracing mechanism 38 are therefore brought closer together causing the X-brace mechanism to expand laterally as illustrated in figures 11 & 12. The upper rear X-brace mechanism 70 operates in a similar manner.

Thus, when the chair is in a folded status the two side frames lie relatively close to one another but are moved apart as the chair is deployed due to the lateral expansion of the front X-brace mechanism 38 and rear X-brace mechanism 70.

The lower rear X-brace mechanism 42, seat 10 and backrest 11 extend to a deployed status as the side frames move apart.

When the chair is fully deployed the lower rear X-brace mechanism is releasably secured in position by placing the hinged brace 48 into an over-centre locked position.

In order to fold the chair the steps described above are carried out in reverse sequence.

Claims (12)

1. A folding chair having a concertinaing seat portion, a concertinaing backrest portion and means for releasably securing the chair in a deployed status mounted upon a framework comprising two similar collapsible side frames connected by a collapsible X-brace arrangement, the side frames and X-brace arrangement being collapsible in unison so that when the chair is in a folded status the two side frames lie relatively close to one another, each side frame comprising a collapsible lattice portion and a supporting rear leg, the lattice portion having constituent members which form a foreleg, seat support, backrest support and armrest, the rear leg being pivotally connected at the upper end thereof to the lattice portion at the juncture of the seat support and backrest support.

2. A folding chair as claimed in claim 1 wherein the chair is releasably secured in a deployed status by weight actuated means, i.e. downward acting pressure applied to the deployed chair acts via the securing means to constrain the chair to a deployed status.

3. A folding chair as claimed in claim 1 or claim 2 wherein each collapsible X-brace comprises four elongate members pivotally connected to form a double-X pattern.

4. A folding chair as claimed in any preceding claim wherein each constituent member of a collapsible lattice portion is reinforced by a duplicate member connected in parallel spaced-apart relation to its twin.

5. A folding chair as claimed in any preceding claim wherein each rear leg is adapted to partially cover the remainder of the chair when the chair is in a folded status.

6. A folding chair as claimed in any preceding claim wherein a centrally hinged bracing device having first and second ends thereof pivotally connected to the seat support and rear leg respectively, is provided on each side frame for arresting the angular movement of the seat support relative to the rear leg.

7. A folding chair as claimed in claim 6 wherein the hinged bracing device is composed of several members pivotally connected to form an expansible linkage which extends toward the lower end of the rear leg when the chair is folded.

8. A folding chair as claimed in claim 6 or claim 7 wherein angular movement of the backrest support relative to the rear leg actuates the hinged bracing device by means of a tie-rod pivotally connected at the upper and lower ends thereof to the backrest support and hinged bracing device respectively.

9. A folding chair as claimed in any preceding claim wherein a concertinaing seat portion constructed mainly from a flexible material such as canvas, has attached thereto a spring device which compels the seat portion to a collapsed status.

10. A folding chair as claimed in claim 9 wherein the spring device is moulded in the form of a zig-zag from a resilient elastic material such as rubber or polyurethane.

11. A folding chair as claimed in claim 9 or claim 10 wherein the seat portion and backrest portion are of similar construction.

12. A folding chair substantially as described herein with reference to figures 1-12 of the accompanying drawing.