GB2081079A

GB2081079A - Stacking armless chairs

Info

Publication number: GB2081079A
Application number: GB8025826A
Authority: GB
Original assignee: LEE CHAIN LONG
Current assignee: LEE CHAIN LONG
Priority date: 1980-08-07
Filing date: 1980-08-07
Publication date: 1982-02-17
Also published as: GB2081079B

Abstract

The chair has side frame members (1) each comprising a rear section bent and recessed inwardly, to allow stacking, with its rear end extending obliquely outwards, each rear end having a tenon fitting in a mortise in the rear leg 2, the rear legs being connected by a straight back member 3, the angle between each rear end of side member 1 and back member 3 ranging from 35-55 DEG so that a backward force on the backrest by the sitter does not tend to disconnect the mortise and tenon joints. <IMAGE>

Description

SPECIFICATION Improved structure of stacking armless chairs Notwithstanding the innumerable varieties of the chairs found on market, arm back-rest chairs with uncollapsible structure are by far the most popular of all due to their simple layout, cheap price, and adaptivity to various places. However, currently available back-rest chairs, particularly those wooden ones, suffer from several disadvantages and are thus not altogether satisfactory. Firstly, unlike the collapsible folding chairs, they are structurally unchangeable. When unused, they cannot be folded to reduce their size so as to save the space they occupy. Next, wooden chairs are generally assembled by fitting two mating parts together to make a joint. For chairs, the members are mostly joined together by mortise & enon joint.Yet when people lean against the back-rest of such chairs, their weight yields a backward component force, the direction of which just coincides with the orientation of the joints, thus resulting in the tendency of the withdrawal of the tenon from the mortise which, unless remedied by reposition the tenon back, always leads to the fracture of the tenon and hence disables the whole chair.

Accordingly, it is an important object of this invention to provide a space-saving armless chair.

It is another object of this invention to provide an improved armless chairs free of the trouble of disjointing between the side frame members and hindlegs thereof.

The objects of this invention will be accompanied by embodiments as referred to in relation with the annexed drawing of this invention wherein: Fig. lisa perspective view of the joint joining the side frame members and hindlegs of conventional armless chairs together; Fig. 2 is a top view of the framework of an armless chair according to this invention; Fig. 3 is a frontal view of the chair as illustrate in Fig.2; Fig. 4 is a side view of the chair as illustrated in Fig.

2; Fig. 5 and Fig. 6 are respectively the top view and side view showing a number of armless chairs according to this invention superposed in a stack; Fig. 7 is a top view revealing the joining of the side frame member and hindleg according to this invention; Fig. 8 is a preferred modification of Fig. 7.

Referring first to Fig. 1, there is shown a mortise and tenon joint found in conventional arm chairs, wherein the end of rail (i.e. side frame member) is shaped into a tenon (M) so as to fit into the mortise (N) cut into the hindleg. The arrow indicates the direction of the backward component force yielded by the weight of a person sitting on the chair and leaning againstthe back-restthereot It can be obvi ously seen that the backward component is adverse to the security of the joint, and this explains why the damages of such chairs always occurs in this portion.

With reference now to Fig. 2, the main feature of this invention resides in that its side frame members (1) are bent and shaped just like a stretched "5" or more preferably, a side view of a frying pan, with both of its rear ends outwardly splaying and fitting snuggly into the hind legs (2), thus forming two rear recessed sides the purpose of which will be later described. Instead of inserting straight into the mating mortise as do the tenoned-side frame members of conventional armless chairs, the rear end side frame member of this invention meet the hindleg (2) in a manner that it intersects the rear frame member (3) at an acute angle ranging from 35 to 55 degrees, and more preferably about 45 degrees, ratherthan at right angle.Rear frame member (3), on the other hand, joining two hindlegs (2) together in a manner similar two that of conventional armless chairs. To reinforce the structure, there is provided another rear frame member (4), which unlike rear frame member (3), bridges the two side frame members instead of the two hindlegs, in similar ways. This device has advantages over conventional armless chairs, since the orientation of the tenoned end of its side frame member does not coincide with the backward component yielded by the weight of the sitters, therefore effectively eliminating the liability of disjointing. Also, the recessed rear sides allow another chair of the same span to straddle on it, thus enabling a number of such chairs to be stacked one on another to save the space when they are not in use (see Fig. 5, Fig. 6).To achieve this purpose, the depth of the recesses must be no less than half of the width of the hindleg, in other words, the width of the rear portion of the seat should not exceed the distance between two hindlegs. Preferably, the legs are cylindrical ratherthan tetragonal prism so as to cope with the joining of this invention. Thus it is fair to say that the depth of the recessed side must exceed the radius of the hindleg. Please refer to Fig. 7, in which there is shown a graphical representation of the characteristic manner of joining according to this invention.

A modification with double tenon as shown in Fig.

8, was found to give even more satisfactory. It is apprehensible that pulling the tenons out of their mating mortises in this device by merely applying a backward force at the back-rest thereof is rather difficult since this involves sideway displacement which is only yielded when two opposite powerful pulling forces are applied to both sides of the chair.

Forthis reason, so long as the tenons are not frame tured, there is no hazard of collapse of the chair due to the disjoining of the rear portion when the chair is loaded with the weight of the sitter, thereby both increasing the safety and prolonging the life of the chair. Heavy load does not increase the hazard of disjoining of this invention provided the structure can withstand its weight, because the friction between the contact surface of tenon and mortise increases with the normal reaction. In contrast, conventional armless chairs fail to offer the sitters plenty of safety and are less durable and space-occupying due to their structural drawbacks. In view of the aforementioned, the novelty and the practicality of the present invention is unquestionable.

1. An improved frame structure of armless,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Improved structure of stacking armless chairs Notwithstanding the innumerable varieties of the chairs found on market, arm back-rest chairs with uncollapsible structure are by far the most popular of all due to their simple layout, cheap price, and adaptivity to various places. However, currently available back-rest chairs, particularly those wooden ones, suffer from several disadvantages and are thus not altogether satisfactory. Firstly, unlike the collapsible folding chairs, they are structurally unchangeable. When unused, they cannot be folded to reduce their size so as to save the space they occupy. Next, wooden chairs are generally assembled by fitting two mating parts together to make a joint. For chairs, the members are mostly joined together by mortise & enon joint.Yet when people lean against the back-rest of such chairs, their weight yields a backward component force, the direction of which just coincides with the orientation of the joints, thus resulting in the tendency of the withdrawal of the tenon from the mortise which, unless remedied by reposition the tenon back, always leads to the fracture of the tenon and hence disables the whole chair. Accordingly, it is an important object of this invention to provide a space-saving armless chair. It is another object of this invention to provide an improved armless chairs free of the trouble of disjointing between the side frame members and hindlegs thereof. The objects of this invention will be accompanied by embodiments as referred to in relation with the annexed drawing of this invention wherein: Fig. lisa perspective view of the joint joining the side frame members and hindlegs of conventional armless chairs together; Fig. 2 is a top view of the framework of an armless chair according to this invention; Fig. 3 is a frontal view of the chair as illustrate in Fig.2; Fig. 4 is a side view of the chair as illustrated in Fig. 2; Fig. 5 and Fig. 6 are respectively the top view and side view showing a number of armless chairs according to this invention superposed in a stack; Fig. 7 is a top view revealing the joining of the side frame member and hindleg according to this invention; Fig. 8 is a preferred modification of Fig. 7. Referring first to Fig. 1, there is shown a mortise and tenon joint found in conventional arm chairs, wherein the end of rail (i.e. side frame member) is shaped into a tenon (M) so as to fit into the mortise (N) cut into the hindleg. The arrow indicates the direction of the backward component force yielded by the weight of a person sitting on the chair and leaning againstthe back-restthereot It can be obvi ously seen that the backward component is adverse to the security of the joint, and this explains why the damages of such chairs always occurs in this portion. With reference now to Fig. 2, the main feature of this invention resides in that its side frame members (1) are bent and shaped just like a stretched "5" or more preferably, a side view of a frying pan, with both of its rear ends outwardly splaying and fitting snuggly into the hind legs (2), thus forming two rear recessed sides the purpose of which will be later described. Instead of inserting straight into the mating mortise as do the tenoned-side frame members of conventional armless chairs, the rear end side frame member of this invention meet the hindleg (2) in a manner that it intersects the rear frame member (3) at an acute angle ranging from 35 to 55 degrees, and more preferably about 45 degrees, ratherthan at right angle.Rear frame member (3), on the other hand, joining two hindlegs (2) together in a manner similar two that of conventional armless chairs. To reinforce the structure, there is provided another rear frame member (4), which unlike rear frame member (3), bridges the two side frame members instead of the two hindlegs, in similar ways. This device has advantages over conventional armless chairs, since the orientation of the tenoned end of its side frame member does not coincide with the backward component yielded by the weight of the sitters, therefore effectively eliminating the liability of disjointing. Also, the recessed rear sides allow another chair of the same span to straddle on it, thus enabling a number of such chairs to be stacked one on another to save the space when they are not in use (see Fig. 5, Fig. 6).To achieve this purpose, the depth of the recesses must be no less than half of the width of the hindleg, in other words, the width of the rear portion of the seat should not exceed the distance between two hindlegs. Preferably, the legs are cylindrical ratherthan tetragonal prism so as to cope with the joining of this invention. Thus it is fair to say that the depth of the recessed side must exceed the radius of the hindleg. Please refer to Fig. 7, in which there is shown a graphical representation of the characteristic manner of joining according to this invention. A modification with double tenon as shown in Fig. 8, was found to give even more satisfactory. It is apprehensible that pulling the tenons out of their mating mortises in this device by merely applying a backward force at the back-rest thereof is rather difficult since this involves sideway displacement which is only yielded when two opposite powerful pulling forces are applied to both sides of the chair. Forthis reason, so long as the tenons are not frame tured, there is no hazard of collapse of the chair due to the disjoining of the rear portion when the chair is loaded with the weight of the sitter, thereby both increasing the safety and prolonging the life of the chair. Heavy load does not increase the hazard of disjoining of this invention provided the structure can withstand its weight, because the friction between the contact surface of tenon and mortise increases with the normal reaction. In contrast, conventional armless chairs fail to offer the sitters plenty of safety and are less durable and space-occupying due to their structural drawbacks. In view of the aforementioned, the novelty and the practicality of the present invention is unquestionable. CLAIMS

1. An improved frame structure of armless, back-rest chairs, characterised by having a pair of side frame members, each having a rear section bent and recessed inwardly, and its end extending obliquely outwards, forming a terminal tenon and fitting into a hindleg of the chair; a pair of hindlegs, each having a mortise in proper position to receive said tenon, and a straight back frame member with its ends joining both said hindlegs, the corresponding pairs of ends of said side frame member and said back frame member forming an acute intersecting angle ranging from 35 to 55 degrees, and preferably about 45 degrees.

2. The frame structure according to claim 1, wherein the legs of the chair are cylindrical.

3. The frame structure according to claim 1, in which the depth of said inwardly recessed rear section of the side frame members is no less than the radius of said hindlegs.

4. A frame structure of armless, back-rest chairs substantially as herein before described with reference to and as illustrated in Figs. 2 to 8 of the accompanying drawings.