GB2143430A - Bases - Google Patents

Abstract

A base for a chair, table or display stand comprising a central part (14) and a plurality of separately formed identical legs (15) is made by providing the central part in the form of a tubular boss with a grooved flange (18) at its lower end and each leg having an inner end (24) of complementary formation to the part of the boss with which it is engaged and a groove (28), and a part (21) of the boss being deformed into contact with the associated leg groove (28) to form an upper flange (21a) to connect the legs (15) to the central part (14) rigidly and permanently. <IMAGE>

Description

SPECIFICATION Improvements relating to bases This invention relatestoa base of the kind, hereinafter called the kind specified, comprising a central partto provide a connection to an article to be supported by the base and a plurality of legs extending from the central part and having parts adapted to engagethe ground. The invention also relates to a method of making a base ofthe kind specified.

The invention has been particularly developed in connection with a base for a seat but the invention is not limited to this application and it can, for example, beappliedto basestorsupporting articlessuchasa table or a display stand.

In the case of a base for a seat, a common form of base is made as a pressure die casting as a one-piece article. Consequentlythe dies required are relatively large, having to accommodate the complete base.

These dies are expensive and the manufacture of such bases is inhibited from varying the design of an established base since to do so would require the provision of an expensive new die for each new base design.

An object of the invention is to provide a base of the kind specified, and a method of making a base of the kind specified, wherebythe above mentioned problem is overcome or is reduced.

According to one aspect of the invention, we provide a base of the kind specified comprising a plurality of legs formed separately from each other and rigidly and permanently connected together.

According to another aspect ofthe invention, we provide a method of making a base according to the first aspect ofthe invention comprising the steps of producing by pressure die casting a plurality of separate, identical, legs and then rigidly and per manently connecting said legs together.

The legs may be connected permanently by means of a permanent deforming operation.

The legs may be permanently connected to a central part.

All the legs may be identical orthe base may comprise a plurality of identical legs and one or more further legs which may or may not be identical to each other.

The central part and the legs may have interengaging male and female formations, the central part or each leg may be deformable to complete the rigid connectiontherebetween.

The central part may comprise a tubular boss having an outwardly projecting flange at each end,the surfaces of the flanges which face each other each having a groove which extendstransverselyto a radius ofthe central part, and each leg having an inner end of complementaryformation to the part of the external surface ofthe flanges ofthe central part with which it is engaged, whereby the grooved flanges rigidlyconnectthe leg partstothecentral part.

At least one of the flanges may be produced by deforming the central part into contact with the associated leg after bringing the central part and leg into a predetermined juxtaposition.

The flange may be deformed by hammering, spinning or pressing.

The legs may be finished by being polished or coated, for example, with an expoxy coating.

An embodiment of the invention will now be described by way of example, with reference to the accompanying drawings, wherein FIGURE lisa diagrammatic side elevation of a chair embodying the invention; FIGURE 2 is a fragmentary plan view of the base of the chairof Figure 1; and FIGURE 3 is a section ofthe line 3-3 of Figure 2.

Referring to the Figures, a chair is indicated generally at 10 and comprises a seat part 11 connected bya column 12 to a base 13.Theseat 11 maybe arranged to pivot about a vertical and/or horizontal axis by virtue of its connection and/or construction of the column 12 and may be, if desired, arranged to be raised and lowered relative to the base 13, as is common place in, for example, executive office chairs.

The base 13 comprises a central part 14 and a plurality, in the present example five, of separately formed identical legs 15. The central part 14 is in the form of a tubular boss having a generally cylindrical internal surface 16and a generally cylindrical external surface 17. At its lower end, the boss 14 has a circumferentially extending flange 18 having a gener allysemi-circularexternal surface 19 and a generally semi-circular internal surface 20.

The boss 14 may be made in any convenient manner such as casting, although other methods may be used such as forging or pressing, and is made with its upper end of the configuration shown in dotted line at 21, namely as a continuation ofthe cylindrical surfaces 16 and 17. As hereinafter to be described, the part 21 of the boss is deformed to occupy the full line position shown at 21 a rigidly to connect the legs 15to the central part 14.

Each leg 15 is made a pressure die casting and may be of any desired configuration over the majority of its length to suit aesthetic requirements.

Each leg 15 has a ground-engageable portion 23 and a central part engaging portion 24 having a partcylindrical surface 25 of a complementary configuration to the surface 17 ofthe central part and a part-circumferentially extending flange 26 of a configuration complementary to the internal surface 20 of the flange 18. At the upper end, each portion 24 is formed at its upper end with a part-circumferentially extending rebate 27 having a part-circumferentially extending groove 28.

Except for the configuration of the portion 24, the remainder of each leg 15 may be of any desired configuration thereby enabling a designerofachairto have a wide range of design choices available.

Because each leg is made separately, the size of die required to cast a single leg is considerably smaller than the die required to case a complete base and hence is considerably more economical. Therefore it The claims were filed later than the filing date within the period prescribed by Rule 25(1) of the Patents Rules 1982.

is economically feasible fora manufacturerto produce a range ofdiesfor a wide range of different leg shapes and hence enables the manufacturerto provide a wide range of bases.

Although in the present example, the base has identical legs, and in the example illustrated five legs radiating equi-angularlyfrom the central part 14, if desired, one or more ofthe legs may be of a different configuration to the remaining legs if a designer should require such a facility.

The base is assembled by positioning the legs 15 in juxtaposition to the central part 14 with the flanges 26 engaged within the groove provided by the surface 20 oftheflange 18 ofthe central part, and with the surface 25 ofthe leg 15 in engagement with the surface 17. The portion 21 ofthe central part 14 is then deformed, for example by spinning, to the position shown atria where the part 21 is deformed into contact with the rebate 27 and into the groove 28 thereofthereby rigidly securing each leg 1 5to the central part 14.

The above described meansforconnecting the legs together ensures a rigid inter-connection between the legs and to the column 12 which is rigidly engaged within the central opening provided by the surface 16, the connection is a permanent one and hence the result is a base in which the legs are permanently connected together as if they had been die-cast in one-piece.

Although in the above example a base with five legs has been described as is conventional for chairs, a different number of legs may be provided if desired.

Also, if desired, instead of the external surface ofthe central part 14 being circular, it may be, for example, of polygonal configuration having a number of sides corresponding to the number of legs, so that in the case of a five legged base, the external configuration ofthecentralpartwould beoctagonalandtheflange 18 would be rectilineary extending instead of partcircumferentially extending and, of course, the portions 24 of each leg would be of a configuration complementaryto the adjacent side ofthe polygon.

The central opening could be again cylindrical to receive a cylindrical column or, if desired, could be of a complementary polygonal configuration to the external polygonal configuration of the central part, in which case suitable connection would be provided for a cylindrical column orthe column could be of a complementary polygonal configuration.

Although intheaboveexamplethecentral part 14 has been described as being deformed from the position shown at 21 to the position shown at 21 a by a spinning operation, the deformation could be done by any other operation such as by a riveting operation or a pressing operation.

Of course, the configuration offlange and grooves may be varied from that described above, so long as a rigid connection provided by inter-engaging male and female formations is achieved. For example, forma tionscorrespondingtothe parts 19and 21 could be provided onthe end of each leg 15 and parts corresponding to the portions 27 and 26 on the central part, in which case a deforming operation would be perfomed on each leg part.

Any other permanent connection may be used.

If desired, the legs may be permanently and rigidly connected together without any central part by providing, for example, inter-engageable male and female formations on the legs and permanentlythe legs to complete the rigid and permanent connection.

In this case the legs would be formed to provide, in combination, a means to receivethe column.

Claims (26)

1. A base of the kind specified comprising a plurality of legs formed separately from each other and rigidly and permanently connected together.

2. Abase according to Claim 1 wherein the legs are permanently connected together as a result of a permanent deforming operation.

3. A base according to Claim I or Claim 2 wherein the legs are permanently connected to a central part.

4. A base according to any one of the preceding claims wherein all the legs are identical.

5. A base according to any one of Claims 1 to 3 wherein the base comprises a plurality of identical legs and one or morefurther legs which mayor may not be identical to each other.

6. A base according to Claim 3, or Claim 4 or Claim 5when dependant upon Claim 3, wherein the central part and the legs have inter-engaging male and female formations.

7. A base according to Claim 6 wherein the central part or each leg has been deformed to complete the rigid connection therebetween.

8. A base according to Claim 6 or Claim 7 wherein the central comprises a tubular part having an outwardly projecting flange at each end, the surfaces oftheflange which face each other each having a groove which extends transverselyto a radius ofthe central part, and each leg having an inner end of complementary formation to the part ofthe external surface of the flanges ofthe central part with which it is engaged,wherebythegrooved flange rigidly connects the leg parts to the central part.

9. A base according to Claim 8 when dependant upon Claim 7 wherein at least one ofthe flanges has been produced by deforming the central part into contactwith the associated leg after bringing the central part and leg into predetermined juxtaposition.

10. A base substantially as hereinbefore described with reference to and shown in the accompanying drawings.

11. Aseat having a base according to any one of the preceding claims.

12. A method of making a base according to Claim 1 comprising the steps of producing by pressure die casting a plurality of separate, identical, legs and then rigidly and permanently connecting said legs together.

13. A method according to Claim 12 wherein the legs are connected permanently together byperform- ing a permanent deforming operation

14. A method according to Claim 12 or Claim 13 wherein the legs are permanently connected to a central part.

15. A method according to any one of the preceding claims wherein all the legs are identical.

16. A method accordingto any one of Claims 12to 14 wherein the base comprises a plurality of identical legs and one or more further legs which may or may not be identical to each other.

17. A method according to Claim 14, or Claim 15 or Claim 1 6when dependant upon Claim 14, wherein the central part and the legs have inter-engaging male and female formations.

18. Amethod accordingto Claim 17whereinthe central part or each leg is deformed to complete the rigid connection therebetween.

19. A method according to Claim 17 or Claim 18 wherein the central part comprises a tubular boss having an outwardly projecting flange at each end, the surfaces of the flanges which face each other each having a groove which extendstransverselytoa radius ofthe central part, and each leg having an inner end ofcomplementaryformation to the part ofthe external surface ofthe flanges of the central part with which it is engaged, whereby the grooved flanges rigidly connect the leg parts to the central part.

20. A method according to Claim 19 when depen- dant upon Claim 18 wherein the central part is deformed into contact with the associated leg after bringing the central part and leg into a predetermined juxtaposition, to produce at leastone of the flanges.

21. A method according to Claim 20 wherein the flange is deformed by hammering, spinning or pressing.

22. A method according to any one of Claims 12to 20 wherein the legs are finished by being polished or coated.

23. A method of making a base substantially as hereinbefore described with reference to the accompanying drawings.

24. A base when made by a method according to any one of Claims 12to 23.

25. A method of making a chair including the step of making a base bythe method claimed in any one of Claims 12 to 23.

26. Any novel feature or novel combination of features disclosed herein and/or shown in the accom panying drawings.