GB2317442A

GB2317442A - Pleated conical lampshade

Info

Publication number: GB2317442A
Application number: GB9619485A
Authority: GB
Inventors: Brian Cecil Sharp
Original assignee: HELIX LIGHTING Ltd
Current assignee: HELIX LIGHTING Ltd
Priority date: 1996-09-18
Filing date: 1996-09-18
Publication date: 1998-03-25
Also published as: GB9619485D0

Abstract

A generally conical uplighter lampshade is formed from a single flat circular or octagonal sheet 1 of a PVC-paper laminate having a plurality of circumferentially spaced creases 6 extending radially outwardly from the centre 5 to the periphery 3. The creases are formed by pressing. A clamp 2 having a similarly profiled surface may attach the shade to a lamp whilst assisting to maintain its shape.

Description

LAMPSHADES The invention relates to lampshades formed in a generally conical shape and in particular relates to a lampshade for uplights.

A prior lampshade for uplights having a scalloped generally conical shape is formed from a plurality of separate pieces of material, each of roughly triangular shape. The pieces are bent into a part-conical shape and are seamed together by the stitching and/or gluing of their adjacent edge areas to one another in a face to face manner. At the centre of the lampshade, the pieces are held together and in shape by a clamp. In another prior lampshade, an elongate arcuate strip of material is folded several times and the ends of the strip are seamed together to form a roughly conical lampshade which is then mounted on a ring or other frame support.

The manufacture of such lampshades is complicated and time consuming because of the need for seaming.

The present invention improves on the prior art by making a lampshade of generally conical shape from a single flat sheet of material without the use of seams and which is substantially self-supporting.

Accordingly the invention provides a seamless lampshade formed from a single flat sheet of material having a periphery and a general centre and provided with a plurality of circumferentially spaced creases extending generally outwardly from the general centre towards ths periphery of the sheet; whereby the sheet is formed into a generally conical shape.

Embodiments of the invention are described below with reference to the accompanying drawings in which: Figure 1 is a side view of a lampshade on a reduced scale; Figure 2 is a plan view of the lampshade without the clamp; Figure 3 is a cross-section through part of the clamp for the lampshade shown approximately life size; Figure 4 is a plan view of another part of the clamp, also shown approximately life size; Figure 5 is a part section through the valley formed between two adjacent panels of the lampshade taken on the line 5-5 in Figure 2; and Figure 6 is a corresponding part section through a part of a prior art lampshade.

Referring to Figures 1 and 2, it can be seen that the lampshade consists of a single sheet of material 1 and a clamp 2. The sheet 1 has a periphery 3 and a hole 4 at its centre 5. Eight circumferentially equally spaced creases 6 extend radially outwardly from the centre of the sheet to the periphery. Each crease forms a V-shaped valley 7; each valley opening in the same direction (upwardly in Figure 1). Each adjacent pair of creases defines a panel 8 and as can be seen in Figure 1, each panel 8 has a substantially part-conical shape. The overall shape of the lampshade is also generally conical but with a scalloping effect brought about by the curvature of the panels.

The sheet is made from a single layer of relatively stiff material or from a flat laminate sheet having at least one plastic layer and is preferably made as a laminate of PVC and paper or cloth. The creases are formed in the sheet in a pressing operation under great pressure which deforms the sheet beyond its elastic limit so that it will not return to its original flat shape and will maintain its formed shape substantially without support. The outline 30 of the flat blank sheet prior to forming s shown in dotted lines in Figure 2. As shown, the flat blank sheet has an octagonal shape but it could equally be circular.

The clamp 2 provides a means of attaching the lampshade to a lamp and also serves to assist in holding the lampshade in shape. As can be best seen in Figures 3 and 4, the clamp includes a relatively stiff outer member 20 having a skirt 21 and a head 22. The skirt is shaped to lie around the centre of the lampshade on its outer surface and has scalloped panels 19 which conform to the shape of the sheet 1. A threaded shaft 23 carried on the outer member 20 extends through the hole 4 in the sheet 1.

An inner member 24 of the clamp is provided by a flat disc of relatively resilient material with radial lobes 25.

The clamp is attached to the sheet 1 by passing the threaded shaft 23 through the hole 4 from the outside.

The inner member 24 of the clamp is then fed onto the threaded shaft 23. A nut and washer (not shown) are then put onto the shaft 23 and used to push the member 24 towards the member 20. As member 24 approaches member 20, the lobes 25 locate in the panels 8 of the sheet and the panels 19 of member 20. As the member 24 approaches member 20 it deforms resiliently into a part-conical shape such that the central part of the sheet 1 is firmly clamped between the two members 20 and 24.

A part section through one of the valleys 7 is shown in Figure 5. A corresponding part section of a prior art lampshade is shown in Figure 6 where it can be seen that adjacent panels 80 are held together by the stitching 81 of their adjacent edge areas in a face to face manner.

The sheet preferably has from three to twentyfour creases 6 formed in it, more preferably four to sixteen, and most preferably has eight. Although the sheet here is shown as polygonal, it could be circular or have any other suitable shape. The maximum dimension of the sheet is preferably between 20 cm and 100 cm and most preferably is about 60 cm. In the case of an uplight lampshade, the hole 4 preferably has a diameter between 0.5 cm and 3 cm and most preferably has a diameter of about 1 cm. For other lampshades the hole may have a larger diameter of about 10-15 cm. The thickness of the sheet is about 0.05 mm. The cone angle of the creases of the sheet is preferably between 10 and 50 , more preferably is between 250 and 350 and most preferably is about 300.

The hole may not be provided in some designs, in which case the clamp may be replaced by some other means of connecting the lampshade to the lamp fitting.

The scalloped shape described in relation to Figures 1 and 2 is only one of many possible designs. For example, a design in which alternate valleys opened in opposite directions is contemplated. Also, the creases may not be straight and may not extend truly radially.

For example, the creases might extend generally tangentially to the central hole 4.

It should be understood when the lampshade is used as a lampshade for an uplight, for which it is particularly suitable, it will be employed with its outer surface downwards.

Claims

1. A seamless lampshade formed from a single flat sheet of material having a periphery and a general centre and provided with a plurality of circumferentially spaced creases extending generally outwardly from the general centre towards the periphery of the sheet; whereby the sheet is formed into a generally conical shape.

2. A lampshade as claimed in Claim 1, further comprising a clamp mounted around the centre of the lampshade.

3. A lampshade according to any preceding claim, wherein the sheet is formed with a hole at its centre.

4. A lampshade as claimed in Claim 3, wherein a threaded shaft mounted on the clamp passes through the hole to provide a mounting for the lampshade.

5. A lampshade as claimed in Claim 4, wherein the clamp comprises an outer member located around the centre of the lampshade on the outer surface thereof and carrying the threaded shaft, and an inner member located against the inner surface of the lamp shade and having the threaded shaft passing therethrough.

6. A lampshade according to any preceding claim, wherein the sheet is a laminate having at least one plastic layer.

7. A lampshade according to any preceding claim, wherein the sheet is a laminate of PVC and paper.

8. A lampshade according to any preceding claim, wherein the sheet is formed with from three to twenty-four creases.

9. A lampshade as claimed in Claim 8, wherein the sheet is formed with eight creases.

10. A lampshade as claimed in Claim 3, wherein the flat sheet has a maximum dimension of from 20 cm to 100 cm and the hole has a maximum dimension of from 0.5 cm to 3 cm.

11. A lampshade as claimed in any preceding claim wherein each crease forms a substantially V-shaped valley and each valley is open in the same direction; whereby the sheet is formed into a scalloped generally conical shape.

12. A lampshade substantially as described herein with reference to the accompanying drawings.