GB2524156A

GB2524156A - Lighting device

Info

Publication number: GB2524156A
Application number: GB1501702.3A
Authority: GB
Inventors: Cressida Grainger
Original assignee: Mathmos Ltd
Current assignee: Mathmos Ltd
Priority date: 2014-01-31
Filing date: 2015-02-02
Publication date: 2015-09-16
Anticipated expiration: 2035-02-02
Also published as: GB201501702D0; GB201401683D0; GB2524156B

Abstract

A lava lamp 10 has a bottle 12 that contains water and a wax. The bottle 12 is supported on a stand 14 with a large and stable base 16 which includes a bulb which heats and lights the bottle and its contents. A cover 22 encloses the bottle, light and most of the stand thereby protecting the bottle 12 from being knocked off, protecting it from damage and retaining heat within the device.

Description

Lighting device The present invention relates to a lighting device and relates particniarly, but not exclusively, to a domestic lighting device in which two immiscible liquids move within an illuminated vessel.

Lighting devices that use the movement of immiscible liquids to create an aesthetically pleasing display, known as Lava Lamps, are well known with the basic technology being disclosed in various patent documents including GB1034255 and US3387396. These lighting devices typically include a vessel containing a transparent, or nearly transparent, liquid such as water and a translucent or opaque wax. Traditionally the glass vessel sits above an Incandescent or halogen bulb which provides light and heat.

The radiant heat from the bulb warms the wax and water causing the wax to melt. Because the wax is immiscible with water, the warmed vesse contents are two immiscible liquids. The wax used is denser than water at, or around, room temperature and less dense than water when heated to between 40 and 50°C. As a result, when the wax is warmed by the radiant heat of the incandescent bulb and is in a molten form, It will rise through the water in the glass vessel as it is heated and then as it cools it will fall within the vessel, thereby creating the interesting and familiar display of the Lava Lamp.

The combination of light and movement of these devices is appealing to both adults and to children. however, it is necessary for the vessel to be removable from its base to allow the bulb to be changed. This leaves the quite heavy vessel, which is formed from glass, potentially vulnerable to being accidentally knocked from the base on which it sits which in turn could lead to breakage of the glass. The removable vessel also leaves the full mains voltage bulb exposed together with associated electrical components which is undesirable for products sold to children. Furthermore, the heat of the bulb, which is necessary to raise the temperature of the contents of the vessel to between 40 and 50°C, also result in the heating of the vessel and the base on which the vessel sits and the temperature of these parts, particularly those close to the bulb and exposed when the vessel is removed, can significantly exceed 50°C. As a result, such lighting devices are regarded as unsuitable for use by children under 14 years.

Preferred embodiments of the present invention seek to overcome the above described disadvantages of the prior art.

According to the present invention there is provided lighting device comprising:-a vessel containing a least one first liquid and at least one material that in liquid form is immiscible with said first liquid; a support body including a base portion for engaging a surface on which the device stands and a vessel engaging portion for supporting the vessel; heat and light producing means for heating and lighting the vessel and located between said support body and said vessel; and a cover member, removably mounted to said support body, for at least partially covering said vessel, said support body and said heat and light producing means, said cover member having at least one partially transparent portion adjacent said vessel.

By providing a cover member that is removably mounted to the support body and covers the vessel, the heat and light producing means and at least part of the support body a series of problems are solved at one time. In particular, the cover stabilises the vessel on the support body and prevents it from being accidentally knocked from the support body and therefore damaged. Furthermore, the cover acts to cushion any impact on the vessel including for example, the impact of the extremely unlikely event of the whole lighting device being knocked over. As a result, in the event that the lighting device is knocked over it is less likely that there is damage to the vessel and even if there is damage to the vessel the liquid and broken pieces of glass are contained within the cover decreasing the likelihood of injury. Furthermore, with the cover in place the vessel cannot be removed from engagement with the support body and therefore a child is unable to access the portion of the device where the heat and light producing means, typically a halogen or incandescent bulb, his located. This therefore protects against accidental burning and accidental electric shock. There is also a decreased risk of sensitive skin being burnt on the outside of the support body.

It is also the case that the cover means retains some of the heat produced by the heat and light producing means which has the advantage that the heat is retained in close proximity to the vessel. This has two advantages, firstly the heat that escapes from the sides of the support body will be directed up the sides of the cover member and the vessel which is adjacent thereto. As a result the vessel will heat up quicker than if all of this heat were allowed to escape by not being consnrained by the cover member.

Furthermore, because this heat is absorbed by the vessel along its whole length the total amount of heat energy being put into the vessel is increased. This therefore allows a longer vessel to be provided that can fulfil the requirements of the Lava Lamp because the cooler liquid, which allows the molten wax to increase its density and begin to fall back to the bottom of the vessel, needs to be further away from the heat source in order to be sufficiently cool for the wax is density to increase. This therefore allows a longer, and therefore more spectacular, lighting device to be created without an increase in energy costs.

The apparatus may further comprise secondary lighting means contained within said cover member.

In a preferred embodiment the secondary lighting means comprises a plurality of lighting devices that are not located between said support body and said vessel.

In another preferred embodiment the plurality of lighting devices comprise a plurality of LEDs.

By including a secondary lighting source the advantage is provided that the lighting device can be made more interesting compared to similar lighting devices of the prior art. In particular, the whole device, the majority of the external surfaces of which are defined by the cover member, can be illuminated with the use of multiple fEDs providing interesting lighting variations. Reflection and refraction within the cover of these secondary light sources will also impact on the light within the vessel.

In a preferred embodiment a gap between a substantially vertical wall of said vessel and a substantially vertical wall of said cover member is less than the largest dimension of horizontal cross-section of said vessel.

In another preferred embodiment a gap between a substantially vertical wall of said vessel and a substantially vertical wall of said cover member is less than 20mm.

By limiting the gap between the cover member and the vessel, the advantage is provided that the vessel is stabilised in its engagement with the support body. With a gap of less than the width of the vessel, the vessel is unable to fall between the cover member and the support body.

In a preferred embodiment the cover member is mounted to said support body via mutually engaging internal and external threads.

By providing a pair of mutually engaging screw threads, the advantage is provided that the cover member is securely fixed to the support body and is extremely unlikely to be accidentally removed. Furthermore, it will be difficult for a child to be able to remove the cover member where a tightly fitting screw thread is employed.

However, the screw thread still allows access to the inside of the cover member allowing the vessel to be removed and the bulb replaced when necessary.

In a preferred embodiment the heat and light producing means comprises a bulb.

In another preferred errhodiment the heat and light producing means further comprises a heater.

In a further preferred embodiment the first liquid comprises water and said material comprises at least one wax immiscible with water when molten.

One of the light producing means and secondary lighting means may comprise a plurality of lighting devices located adjacent a top of said vessel and provided with an electrical supply via an electrical conductor from said base portion.

By providing the main and/or the secondary lighting means adjacent the top of the vessel the advantage is provided that additional aesthetically pleasing lighting effects can be provided within the device. A fine wire can also be used to supply power from the base without spoiling the aesthetics of the device. Furthermore, by locating lighting above the vessel the advantage is provided that more of the space adjacent the base of the vessel can be used for heating the vessel and the liguids contained therein. This speeds up the time required to heat the vessel and to melt the wax component. This also increases the expected working life of the lighting means which are often shortened when working at raised temperatures.

Preferred embodiments of the present invention will now be described, by way of example only, and not in any limitative sense, with reference to the accompanying drawings in which:-Figure 1 is a view from above of the device of the present invention; Figure 2 is a side view of the device of figure 1; Figure 3 is a sectional side view, along the line A-A of the device of figure 1; and Figure 4 is a perspective view of the device of figure 1 showing some internal detail.

Referring to all of the figures, a lighting device 10 has a vessel, in the form of bottle 12, that contains a first liguid, which is typically water being either fully transparent or containing a small quantity of colouring.

The bottle 12 also contains a material, generally a wax, which is solid at room temperature and when it melts, typically at a temperature of 40 to 50°C, is immiscible with the water that forms the first liquid.

The device 10 also includes a support body 14 that includes a base portion 16 for engaging a surface on which the device 10 stands. Extending from the base portion 16 is a support column 18 at the top of which is located a vessel engaging portion in the form of bottle support 20.

The device 10 further includes heat and light producing means, in the form of a lighting bulb (not shown) that is contained within the bottle support 20. When turned on the bulb illuminates the bottom of bottle 12 and the heat produced by the bold raises the temperature of the bottle and the water and wax it contains. The bulb is typically an incandescent bulb although other light producing bulbs, for example halogen bulbs, may be used.

If necessary an additional heat source, in the form of a small heater, can be included to heat the bottle 12 and its contents. Furthermore, where a heating device is used the bulb can be replaced with low voltage lighting devices, such as LEts, that do not produce sufficient heat on their own to heat the bottle and its contents.

A cover member 22 also forms part of the device 10.

The cover member 22 has a tubular body portion 24 and a lid 25. As a result, the cover member 22 covers and surrounds the bottle 12, the bulb in the bottle support 20, the support column 18 and part of the base 16. In the embodiment shown the cover member 22 entirely encloses the bottle 12, the bottle support 20 and the support column 18 although the cover member 22 could alternatively include one or more apertures, in particular in the cooler areas away from the bottle support 20. The lid 25 has an annular lip extending down from the lower surface sized so that it extends around the cap of the bottle 12 thereby adding to the stability of the bottle as it sits on the bottle support 20.

The base member 16 can be divided into a circular inner section 26 and an annular outer section 28. The inner section 26 is thicker than the outer section 28 and the edge 30 of the inner section 26 engages the cover member 22 in such a way as to fix the cover member 22 to the base 16. This fixing is by some non-permanent means allowing the cover member 22 to be removed in turn allowing access to the bottle 12 and the bulb contained within the bottle support 20, so that the bulb can be changed. For example, the edge 30 of inner section 26 may be provided with an external thread and the open end of cover member 22 may be provided with an internal thread so that these mutually engaging threads can maintain the cover member 22 in engagement with base 16 whilst still allowing The cover member 22 to be removed if necessary. Although engaging threads have been described, any suitable system for fixing the cover 22 securely but removably to the base:6 may be used in the present invention. For example, a tight interference fit, a bayonet type fitting, locking screws/bolts or a system of locking clips may be used.

The length of the cover member 22 is divided into three sections including a transparent section 32 through which the bottle 12 and its contents can be seen. The remaining sections 34 and 36 of cover member 22 are preferably not transparent so as to at least partially hide the support column 18 and bottle support 20 and the uppermost portion of bottle 12. Most preferably the sections 34 and 36 are semi-transparent or translucent for example using an effect known as "frosted glass" allowing some light to pass through. This is particularly useful where the device 10 includes a secondary lighting means in the in the form of a plurality of lighting devices which -10 -are preferably LEts (not shown) -These tEDs are preferably located in the vicinity of the support column 18 and the neck 38 of bottle 12, both of these features being contained within the non-transparent portions 34 and 36 of the cover 22.

The cover 22 is preferably formed from a thermoplastic material, for example Perspex, and is formed as a tube of circular cross-section. The main portion of bottle 12, that is the section visible through transparent portion 32 of cover 22, also has a circular cross-section having an external diameter P1 that is slightly less than the internal diameter P2 of cover 22. The maximum gap between the bottle 12 and cover 22 (P2 -D1) is less than and preferably significantly less than the external diameter P1 of bottle 12. Typically the (D2 -D1) is less than 20 mm.

As an alternative, or additional, arrangement of the lighting within the device 10, a light source can be provided in the lid 25. This is preferably in the form of low voltage lights such as LEts and these are most preferably formed in a ring that is formed into or attached to the lid 25. Alternatively, a ring with LEts attached to it could be placed over the neck 38 of bottle 12 so that a thicker portion of the neck 38 limits the position of the ring to a location sufficiently far up the neck that the lights remain in the non-transparent sections 34 of the cover 22. This arrangement of a ring of LEDs around the top of the bottle results in a halo of light being shone down onto the bottle 12 and its contents. Because the main power supply is in the lower section 36 of the cover member 22 it is necessary to provide a conductor up through the middle section 32 into the upper section 34. This -11 -conductor is typically in the form of a fine wire which is attached to the inside of cover 22. This fine wire will be visible in the transparent section 32 of cover 22. Because of the low voltage and current reguirements of LED lights the wire can be of a very fine gauge and therefore barely noticeable not interfering with the aesthetics of the device 10, although alternative conductors including thicker wires, metal strips and conductive paints could be used.

The assembly of the device 10 will now be described.

The support body 14 is placed on a stable surface and bottle 12 is placed into engagement with bottle support 20.

The cover 22 is placed over the bottle, bottle support and support column 18 and its internal thread is engaged with the external thread on edge 30 of inner portion 26 of base 16 so as to hold the cover 22 in place.

The lighting device 10 is now ready for use, is plugged into an electricity supply and switched on. The bulb in bottle support 20 lights up and begins to heat the bottle 12 and its contents. When the bottle and contents reach a temperature of around 40 to 50°C the wax melts and moves within the water in a manner familiar to users of a Lava Lamp. The secondary lighting LEDs may also be switched on and these may be, under the control of a processor, programmed to change colour and provide additional lighting interest in a manner familiar to persons skilled in this art.

In the event that the device 10 is knocked the close proximity of the cover 22 to the bottle 12, including the lid 26 being close to the top of the bottle, means that the -12 -bottle stays in position. In the unlikely event of the device being knocked over, this being unlikely due to the width and weight of the base 16, the bottle will still remain in position making it unlikely to become broken.

Furthermore, the bottle may be supported by cushioning members, for example in the form of foam, which can be placed in the gap between the bottle and the cover 22 in the non-transparent regions 34 and 36. Even in the event of the bottle 12 becoming broken the water and wax contents of the bottle would remain within the cover 22 and cut out circuitry would immediately cut the electricity supply.

It will be appreciated by person skilled in the art that the above embodiments have been described by way of example only and not in any limitative sense, and that variolls alterations and modification are possible without departure from the scope of protection which is define by the appended claims. For example, the embodiment shown in the figures is designed as a floor standing lighting device. As a result, the support column 18 has a length of around 750 imu. However, it should be noted that the length of the support column 18 can be varied and for table-top versions of the lighting device the support column could be entirely removed.

Claims

-13 -Claims 1. A lighting device comprising:-a vessel containing a least one first liquid and at least one material that in liquid form is immiscible with said first liquid; a support body including a base portion for engaging a surface on which the device stands and a vessel engaging portion for supporting the vessel; heat and light producing means for heating and lighting the vessel and located between said support body and said vessel; and a cover member, removably mounted to said support body, for at least partially covering said vessel, said support body and said heat and light producing means, said cover member having at least one partially transparent portion adjacent said vessel.
2. A device according to claim 1, further comprising secondary lighting means contained within said cover member.
3. A device according to claim 2, wherein said secondary lighting means comprises a plurality of lighting devices that are not located between said support body and said vessel.
4. A device according to claim 3, wherein said plurality of lighting devices comprise a plurality of LETs.

-14 -
5. A device according to any of the preceding claims, wherein a gap between a substantially vertical wall of said vessel and a substantially vertical wall of said cover S member is less than the largest dimension of horizontal cross-section of said vessel.
6. A device according to claim 5, wherein a gap between a substantially vertical wall of said vessel and a substantially vertical wall of said cover member is less than 20mm.
7. A device according to any of the preceding claims, wherein said cover member is mounted to said support body via mutually engaging internal and external threads.
8. A device according to any of the preceding claims, wherein said heat and light producing means comprises a bulb.
9. A device according to any of the preceding claims, wherein said heat and light producing means further comprises a heater.
10. A device according to any of the preceding claims, wherein said first liguid comprises water and said material comprises at least one wax immiscible with water when molten.
11. A device according to any of the preceding claims, wherein at least one of said light producing means and said secondary lighting means comprises a plurality of lighting devices located adjacent a top of said vessel and provided -15 -with an electrical supply via an electrical ccnductcr frcm said base portion.
12. A lighting device substantially as hereinbefore described with reference to the accompanying drawings.