GB2296558A

GB2296558A - A lamp stand

Info

Publication number: GB2296558A
Application number: GB9426459A
Authority: GB
Inventors: Richard Martin Glover
Original assignee: Individual
Current assignee: Individual
Priority date: 1994-12-31
Filing date: 1994-12-31
Publication date: 1996-07-03
Anticipated expiration: 2014-12-31
Also published as: GB9426459D0; GB2296558B

Abstract

A free standing electrical lamp (10) with light bulb holder (21) mounted on a base (11) with a friction clutch means (23) allowing the height of the bulb holder to be adjusted relative to the base (11). The bulb holder (21) is connected to a power source by an electrical cable (36) passing through the base and sufficient cable is stored as resiliently retractable coils (37) within the base to allow for a full range of height adjustment without feeding cable into or removing cable from the base. <IMAGE>

Description

A Lamp Stand This invention relates to free standing lamps, and in particular but not exclusively to standard lamps.

Standard lamps in which the height of the bulb holder relative to the ground or to the base of the lamp are known. A problem associated with adjustable height lamps is that the electrical power connection to the bulb holder must be able to accommodate the range of height adjustment.

If the holder has a power cable that is external of the lamp base then it is both unsightly and dangerous since the lamp may be pulled over if a passer by catches the loose cable. Alternatively if the power cable passes through the lamp base to the bulb holder, as is known in the prior art, the cable must be fed into the base as the height of the bulb holder is increased, and must be pulled out of the base as the height of the bulb holder is lowered. This is awkward and unsatisfactory and makes the adjustment a difficult and time-consuming business.

The present invention seeks to overcome the above problem.

According to the present invention there is provided a free standing electrical lamp with light bulb holder mounted on a base such that the height of bulb holder relative to the base, or the surface on which the lamp stands, is adjustable, and the bulb holder is connected to a power source by an electrical cable passing through the base, characterised in that sufficient cable is stored within the base to allow for a full range of height adjustment without feeding external cable into or removing internal cable from the base.

Preferably a portion of the cable within the base is in the form of a retractable store of cable, for example in the form of resiliently retractable coils. These coils of cable may be housed in a hollow support located within the base.

Conveniently the bulb holder is attached to a tube telescopically mounted within the hollow support; the hollow support is also tubular, and preferably the telescopic tube is releasably held at its selected height, by a friction clutch device which comprises a coaxial split sleeve located concentrically between the hollow support and the telescopic tube and which is compressed to grip the tube.

Preferably the tube is prevented from rotating through 360 degrees relative to the base.

Also according to the invention there is provided a method of making a free standing lamp with a bulb holder which is mounted on a base such that the height of the bulb holder is adjustable relative to the base, characterised in that the lamp is provided with a reservoir of cable located within the base for adjustment of the bulb holder to its maximum height, and which is resiliently retractable for storage of the cable when at intermediate height or minimum height.

The invention will be described by way of example and with reference to the accompanying drawings in which: Fig. 1 is a lamp according to the present invention, and Fig. 2 is a section in the line II-II of Fig. 1.

Now with reference to Figures 1 and 2 there is illustrated a free standing standard lamp (10) which comprises a lamp base (11) which has a circular foot (12).

The circular foot has the form of an inverted dish with a central hole (20). A coaxial elongate hollow support tube (13) has an externally screw threaded end portion (14, 15) at each end thereof. One end (15) is inserted through the hole (20) in the foot (12) and receives a nut (16), and the other end (14) has a circular collar (17) thereon which may be screwed thereon. Alternatively, the collar (17) may have radial ribs that engage the threaded portion (14) and is held in place by a sleeve (24) to be described later The collar (17) has a peripheral downturned rim (18) to receive the upper end margin of a coaxial hollow shell (19), the lower end of which is located in a coaxial annular boss (21) on the upper surface of the foot (12).

The foot (12) is clamped against the shell (19) by screwing the nut (16) onto the threaded end portion (15). The shell (19) in this case is cylindrical but could be any desired hollow configuration such as spindle shaped.

An electrical bulb holder (21) is attached to the upper end of a coaxial tube (22) which is telescopically mounted coaxially within the support tube (13). The telescopic tube (22) passes through a cylindrical friction clutch device (23) which is screwed onto the upper thread end portion (14) of the support tube (13).

The clutch device (23) comprises the cylindrical sleeve (24) which has internal screw threaded portions (25, 26) at each end. The upper screw threaded portion (25) receives a flanged externally threaded nut (27) having a centre hole through which the tube (22) passes. The outer peripheral surface (28) of the flange may be knurled to provide for improved grip and has a frustoconical surface 30 at its lower end. The lower screw threaded portion (26) cooperates with the upper screw threaded portion (14) of the support tube (13). An internal annular frustoconical shoulder (29) is provided within the cylindrical sleeve (24) adjacent the lower internal screw threaded portion (26).

A cylindrical plastic split bush (31) is located concentrically within the sleeve (24) to surround the telescopic tube (22). The bush (31) has frustoconical ends that match the surfaces (29 & 30) and has a length such that it is compressible between the nut (27) and the annular shoulder (29). When the bush (31) is compressed the split (32) therein allows the bush to shrink circumferentially and grip the external surface of the tube (22). To release the friction grip clutch (23) the nut (27) is undone so as to release the compressive load on the bush (31).

The bush (31) may be made from any suitable plastics material such as nylon 6, nylon 66, polypropylene, high density polyethylene.

The tube (22) is held rotationally fast relative to the lamp base (11) by an abutment in the form of a grub screw (35) which passes through an aperture (33) in the bush (31) to engage in an elongated axial groove (34) in the external surface of the tube (22). The grub screw (35) also serves to hold the bush (31) in place and prevent 360 degrees rotation of the tube (22) if the nut (27) is completely removed.

The power cable (36) connected to the bulb holder (21) passes through the telescopic tube (22) into the hollow support tube (13) through a cable restraint (39) mounted in the end portion of the tube (22) . The cable (36) is stored in coils (37) in the lower portion of the hollow support tube and the coils (37) are retained in the support tube (13) by a closure (40), preferably a resilient removable closure which may be formed from moulded plastics material. The cable (36) then passes into the hollow of the foot (12) and out through a sleeved hole (38)for connection to a power source.

The cable coils (37) are resilient and contain sufficient spare cable to allow the telescopic tube (22) to be adjustable over a height range of about 0.6 metres. When the bulb holder (21) is lifted the cable unwinds to provide for the necessary increase in length of cable within the base. When the bulb holder (21) is lowered from an elevated position, the resilience in the coils of cable causes the coils to reform to take up the now excessive cable length. The coils of cable may be resilient in themselves, or may have a resilient cord passing through the coils.

It will be appreciated that in some standard lamp designs it will be possible to remove the shell (19) so that the lamp stand consists essentially of only the support tube (13) with the coiled cable therein.

In other designs it may be possible to house the excess cable in the spacing between the shell (19) and the tube (13), or even within the underside hollow of the foot (12).

It will also be appreciated that the telescopic tube may form only a portion of a radially extending arm, which may be curved, with the bulb holder on the outer end of the arm. By radial is meant radial with respect to the longditudinal axis of the support sleeve tube (13).

Claims

1. A free standing electrical lamp with light bulb holder mounted on a base such that the height of bulb holder relative to the base is adjustable, and the bulb holder is connected to a power source by an electrical cable passing through the base, characterised in that sufficient cable is stored within the base to allow for a full range of height adjustment without feeding external cable into or removing internal cable from the base.

2. A lamp as claimed in Claim 1 wherein a portion of the cable within the base is resiliently retractable, preferably in the form of resiliently retractable coils.

3. A lamp as claimed in Claim 1 or Claim 2 wherein the cable is stored within an elongated hollow support housed within the base.

4. A lamp as claimed in any one of Claims 1 to 3 wherein the bulb holder is attached to a sliding tube telescopically mounted within the support.

5. A lamp as claimed in Claim 4, wherein the telescopic tube is releasably held at its selected height, by a friction clutch device which comprises a coaxial split bush located concentrically between the telescopic tube and a sleeve fixed to the support, and which is compressed to grip the tube.

6. A lamp as claimed in any one of Claims 1 to 5, wherein rotational movement of the bulb holder relative to the base is restricted such that the bulb holder cannot rotate through 360 degrees when the bulb holder is assembled to the base.

7. A lamp as claimed in Claim 6, when dependant upon Claim 4, wherein the rotation of the bulb holder is limited by an abutment fixed relative to the base engaging in a longitudinally elongated groove in the tube.

8. A lamp as claimed in Claim 7, wherein the tube is held rotationally fast by a screw means fixed relative to the base which passes through a co-operating aperture in the split bush to engage in said groove.

9. A lamp according to any one of Claims 1 to 8, wherein the lamp is a standard lamp and the cable enters the base adjacent the foot of the base.

10. A lamp according to Claim 4, or Claim 5, or any one of Claims 6 to 9 when dependant upon Claim 4, wherein the bulb holder is fixed to the tube coaxially of the lamp base.

11. A lamp as described herein and as illustrated in the accompanying drawings.

12. A method of making a free standing lamp with a bulb holder which is mounted on a base such that the height of the bulb holder is adjustable relative to the base, characterised in that the lamp is provided with a reservoir of cable located within the base for adjustment of the bulb holder to its maximum height, and which is resiliently retractable for storage of the cable when at intermediate height or minimum height.