More particularly, the present invention relates to a flame effect assembly primarily for use in a space heater such as an electric fire for use in, for example, a private dwelling to provide heat as and when required, with the added realism of a real fire by virtue of the flame effect assembly.

Many known electric fires incorporate an effect to replicate a flame effect.

An extensive range of flame effect concepts have been used, and these have been often quite complex and thus expensive. Further, these known flame effect concepts can require the electric fire to have a considerable depth, this being considered undesirable for aesthetic reasons, ease of installation especially in fire surrounds, and as regards cost due to the amount of material eg. metal, required for the construction.

A slim construction is considered desirable so that the fire can fit snugly and cleanly into a shallow rebated fire surround, against a wall or in a shallow recess, to improve the aesthetic appearance of the installation, and to make the construction cost effective.

For many years flame effects have been used involving a reflecting means of one form or another, which is slowly rotated to give an effect as the reflected light falls onto a screen which is viewed either directly or through a front glass panel.

Such arrangements are disclosed in British Patent Specification Nos. 450941, 164143,1272644 and US Patent Specification No. 5642580. These involve the use of coloured bulbs or other means of producing yellow/red colours associated with flames.

An aim of the present invention is to provide a flame effect assembly which is realistic and which, when used in, for example, an electric fire, enables the fire to have a slim and cost effective construction.

According to the present invention there is provided a flame effect assembly comprising a drum having a longitudinal axis about which the drum is arranged to, in use, be rotated, the drum being capable of at least partially transmitting light therethrough from a light source, transverse to said longitudinal axis, with means being incorporated in the drum for producing shadows in the light which is transmitted through the drum generally transverse to said longitudinal axis, and onto a screen.

In one embodiment of the present invention the drum is arranged with said longitudinal axis horizontal, with one end region of the drum being connected to motor means eg. an electric motor, for rotating the drum at a constant speed about the longitudinal axis, and the other end mounted for free rotation by virtue of a spring mounting which facilitates withdrawal. Alternatively the motor means may be arranged to rotate the drum at a varying rotational speed to further enhance the flame effect produced by the present invention.

Further, the longitudinal axis of the drum is preferably, though not essentially, the central axis of the drum. By having the drum rotatable about an eccentrically positioned longitudinal axis, whilst bearings can be undesirably loaded, the flame effect may be further varied to advantage.

The drum itself is preferably transparent, and preferably made from a transparent plastics material, eg. a polycarbonate material, the said means for producing shadows being preferably formed by a predetermined random pattern carried by the drum, the pattern comprising apertures defined by a closed network which can be provided by paint of any desired colour. Said network may be totally opaque so that no light passes therethrough or translucent to allow an amount of light therethrough. Further the apertures in the pattern may, if desired have a coloured hue eg. beige or amber, which can, if required, vary in density gradually over the drum eg. diagonally, to soften and enhance the flame effect.

To produce the required pattern and the coloured hue the outside surface of the drum which may be solid or hollow, may be painted, or appropriately etched, and also painted to produce the hue, if required. Alternatively, the drum which is preferably hollow, may be painted and/or etched on its inside and/or outside surface to produce the required pattern. Further, the pattern and hue if required, may be alternatively produced on a flexible transparent sheet eg. acetate, and folded into a generally cylindrical form to be then inserted into the hollow drum, the inherent resilience of the normally planar sheet biassing the sheet against the inner wall of the drum. Preferably the sheet is approximately of dimensions which fit the length and internal configuration of the drum To further enhance the flame effect produced by the pattern described here above, a spiral strip of translucent material eg. red in colour, may be provided on the drum again, for example, by painting the outside or inside surface of the drum with a suitable paint or ink, or formed actually in the material of the drum, such as when the drum is made of a polycarbonate or other plastics material. Alternatively a spiral of translucent coloured eg. red, material eg. a plastics material, may be located on the inside surface of the drum and either secured in position by a suitable adhesive, drum end caps, or by its inherent flexibility due to its spiral configuration, or located between the inside surface of the drum and the said transparent sheet comprising the said pattern, the transparent sheet holding the said spiral in position against the inside wall of the drum Further the drum may alternatively be hollow and made of an opaque material eg. metal with holes formed therein in a desired pattern, to allow for the transmission of light and the production of shadows as the drum is rotated. If required an acetate, coloured or clear, with or without a coloured spiral can be included in this latter embodiment.

The drum is preferably cylindrical in shape, though the transverse cross section may alternatively have a desired polygonal shape. To explain, with a hollow drum having a polygonal cross-section, both the internal and external transverse cross section may have the same polygonal configuration, different polygonal configurations, or only one cross section could be polygonal with the other cylindrical, the latter two possibilities distorting light and enhancing the images produced.

With the drum arranged horizontally it is especially useful for producing a flame effect in an electric fire. In such an instance the horizontal drum is located in the front lower region of the fire with one or more lamps forming a light source and providing preferably white light, located therebelow so that white light passes through the drum onto the screen which is positioned primarily above the drum and to the rear of the fire, in what could be termed an upper slim portion of the fire.

Preferably the horizontal drum is rotated so that the lower portion of the drum moves towards the rearwardly positioned screen ie. clockwise when viewed from the left hand end of the drum, to thus enhance realism by providing for simulated growing flames.

In one embodiment the screen is preferably straight and virtually planar in its upper region, and curved in a concave manner in its lower region. Further whilst the surface of the screen may be polished and reflective, it is preferably covered with a translucent plastics sheet to soften the ever moving image of flames produced on the screen by the rotating drum. This translucent plastics sheet forms a semi-opaque diffusing screen, and the flame effect on this screen is further enhanced if viewed through a front tinted glass panel which is preferably screen printed with a variable density of different relevant colours eg. yellow and red, this allowing varying colour and light densities to be viewed.

Also a glass screen of varying thickness may, if desired, be placed between the drum and the said screen, to enhance the flame image produced by the pattern and spiral of the rotating drum, by further varying, softening and merging the images and thereby producing a more realistic effect.

In another embodiment the screen has a series of randomly arranged ie. spaced apart, generally vertical ribs profiled therein ie. pressed therein, with the major part of the screen being black and with a simulated reflective, preferably gold coloured, flame region, in the form of a series of peaks or generally shaped flames.

Again the flame effect is enhanced by a front tinted glass panel which may be screen printed in one colour or in different relevant colours eg. yellow and red, possibly of varying density.

The present invention will now be further described, by way of example, with reference to the accompanying drawings, in which:- Fig. 1 is a perspective cutaway view of one embodiment of a fire incorporating the present invention; Fig. 2 is a plan view of the plastics sheet for use in the rotatable drum of the present invention in planar condition; Fig. 3 is a perspective cutaway view of a modified form of the present invention; Fig. 4 is an exploded view of a preferred form of rear screen used in Fig. 3; and Fig. 5 is a perspective cutaway view of another embodiment of a rotatable drum for use in the present invention.

The embodiment of flame effect assembly constructed according to the present invention and shown in Figs. 1 and 2 of the accompanying drawings, is shown as part of an electric fire 1 and comprises a horizontally arranged hollow drum 3 positioned in the lower frontal region of the fire, the drum 3 being rotatable at a constant speed about the central longitudinal axis of the drum 3 by an electric motor 5. Beneath the drum 3 are located a light source in the form of two electric lamp bulbs 7 each producing white light which is transmitted through the rotating drum 3 as discussed herebelow. The light transmitted by the drum 3 then passes in the embodiment of Figs. 1 and 2, through a glass screen 9 of varying thickness which is located above the drum 3, and onto a screen 11 which is viewed through a front tinted glass panel 13. A glass fibre, GRP or plastics material, simulated coal or other fuel bed moulding 15, is located over the front of the lower region of the fire to shield the electric lamp bulbs 7 and the rotating drum 3 from view, the bulbs 7 illuminating the simulated fuel bed 15 which is semi-opaque, from underneath so that the light transmitted by the simulated fuel bed adds, together with the flame effect, to the realism of the simulated solid fuel effect fire.

The hollow drum 3 is a hollow cylinder made of transparent plastics material, with end caps 17 which are rotatably mounted in the fire 1, one end cap 17 being freely rotatably mounted in a spring manner to facilitate withdrawal of the drum, whilst the other end is connected to the electric motor 5. The electric motor 5, in use, rotates the drum at a constant speed. Alternatively the drum speed can be continuously variable. Further, other drive means may be substituted.

Means for producing random shadows or flame images in the form of a rectangular transparent flexible plastics sheet 19 eg. acetate (see Fig. 2), painted or otherwise marked with a closed pattern network which defines a random arrangement of randomly shaped apertures 21, is rolled into a cylinder and dimensioned to fit inside the hollow drum 3, the sheet being biassed against the inside wall of the drum by the inherent resilience of the normally flat flexible sheet. The paint or other marking is opaque and the apertures 21 are also painted or printed with a transparent hue of brown/beige colour. This hue varies in density diagonally across the rectangular sheet as can be seen in Fig. 2, this hue softening the image produced by the rotating drum 3 so that the simulated flame images tend to merge with each other to varying degrees, as in a real fire, thereby enhancing realism.

In an alternative embodiment (not shown) the pattern or means for producing randomly moving shadows can be painted or etched on the inside surface of the drum 3, or more preferably on the outside surface, the latter being of necessity if a solid drum is alternatively used.

To further enhance realism a spiral, translucent strip 23 which is red in colour, is located on the inside wall of the drum 3. In the embodiment illustrated in Figs. 1 and 2, this strip 23 is located between the flexible plastics sheet 19 and the inside wall of the drum 3, with the sheet holding the strip 23 in the desired position. This translucent red strip 23 allows red light to pass therethrough so that a moving red image is achieved on the screen, contrasting with other yellowish flame images, and enhancing realism. In an alternative embodiment where the drum 3 is hollow with the pattern or means for producing shadows, painted or etched on the inside or outside surface of the drum, the spiral, translucent strip 23 is located on the inside wall of the drum 3, and held there by the end caps 17, the natural resilience of the spiral configured strip 23, and if necessary, an adhesive. Still further alternatives provide for the pattern and/or strip 23 to be formed during manufacture, in the material from which the drum is produced.

In order to produce growing flame images, the drum 3 is rotated by the electric motor 5 so that the lower region of the horizontally arranged drum moves towards the screen 11 ie. the drum rotates clockwise when viewed from the left hand end.

The screen 11 consists of a reflector 25 and a front semi-opaque diffusing screen 27 which softens and merges the moving images to enhance realism. The screen 11 is virtually planar in its upper region but concave in its lower region, with the varying thickness glass screen 9 being located in generally horizontal manner ie. with its median plane arranged horizontally, under the concave lower portion so that light passing through the drum 3, passes through the varying thickness glass screen 9 which also softens and merges the randomly moving sharp images produced by the pattern on the drum 3, prior to impinging on the said screen 11.

The front tinted glass panel 13 referred to here above, is located in front of the screen 11 and varying thickness glass screen 9, and is screen printed with a variable density of different regions of colour eg. yellow and red, to allow varying colour and light densities to be viewed, thus enhancing the flame effect achieved and the realism of the flame effect produced.

In another embodiment of the present invention, illustrated in Figs. 3 and 4 of the accompanying drawings, the same reference numerals as used in the embodiment of Figs. 1 and 2 are used to identify like features. To explain the main differences between the respective embodiments, is the inclusion, in the embodiment of Figs. 3 and 4, of a different concept of screen 11, and the omission of the variable thickness glass plate 9.

The screen 11 in the embodiment of Fig. 3, comprises a major portion 29 which is dark in colour, preferably black, and of a matt-type finish, ie. of none or limited reflectivity, with a series of reflective regions 31, preferably gold coloured, of varying elongate, upwardly extending shapes, which, in use, enhance flame simulation as produced by the rotating drum of the present invention. The reflective regions 31 have upwardly extending ribs or ridges 33 formed at spaced apart locations, which further enhance the required flame effect simulation. Such ribs can also be provided in the major part 29.

To manufacture the major part 29 of the screen 11, and the said reflector regions 31, a sheet of metal is stamped out with the desired, generally rectangular, outer periphery, and with the cutout desired shapes 32 for the reflective regions 31.

A sheet 35 of preferably gold coloured reflective material, pressed to form the desired ribs, is then secured over the back of the major part 29 over the cutout shapes in the major part 29, to thus form the desired random ribbed, reflective, growing flame shapes to enhance the flame effect.

Further the major part 29 extends down behind the drum 3, so that its lower edge 37 is level with the horizontal median plane of the drum 3. In this way light passing through the drum is collected by the screen 11 and passed forwards to the front tinted glass panel (not shown in Fig. 3). Alternatively the lower edge 37 can extend below the horizontal median plane of the drum 3, to the same effect.

The drum 3 of the present invention can alternatively be hollow and made of an opaque material e. g. a metal, with holes 39 formed therein in a desired pattern, as shown in Fig. 5 of the accompanying drawings, to thus allow for the transmission of light and the production of shadows as the drum is rotated. If required an acetate, coloured or clear, with or without a red spiral can be included.

Further, whilst reference is made hereabove to a hollow cylindrical drum 3, or a solid drum, the transverse external cross section of the drum can be alternatively polygonal, and the internal cross section of the drum when hollow, can be cylindrical or polygonal, the selection of differing configurations, especially for internal and external transverse cross sections providing for distortion of the images produced, and for added enhancement of realism.

The present invention thus provides a simple, cost effective flame effect assembly which has realism and which can, with advantage, be installed in an electric fire of desired dimensions and aesthetic appeal.