Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F21—LIGHTING
  • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
  • F21V17/00—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages
  • F21V17/04—Fastening of component parts of lighting devices, e.g. shades, globes, refractors, reflectors, filters, screens, grids or protective cages the fastening being onto or by the light source
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J61/00—Gas-discharge or vapour-discharge lamps
  • H01J61/02—Details
  • H01J61/30—Vessels; Containers
  • H01J61/35—Vessels; Containers provided with coatings on the walls thereof; Selection of materials for the coatings
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01K—ELECTRIC INCANDESCENT LAMPS
  • H01K1/00—Details
  • H01K1/28—Envelopes; Vessels
  • H01K1/32—Envelopes; Vessels provided with coatings on the walls; Vessels or coatings thereon characterised by the material thereof

Definitions

• This invention relates to electric light devices both of incandescent type, normally known as “light bulbs” or lamps, and of discharge type, normally known as “fluorescent tubes”.
• incandescent type normally known as “light bulbs” or lamps
• fluorescent tubes normally known as “fluorescent tubes”.
• coloured lamps are, of course, well known having standard clear or pearl glass enclosures as made, but later coated, typically lacquered, to give the desired or required colours.
• One alternative by way of using self-coloured glass is presumably yet more expensive, or it would be done by bulb manufacturers.
• Such cover product requires a material capable of withstanding temperatures generated at light device enclosures, typically up to 300 degrees Centigrade for incandescent bulbs (though rather less for fluorescent tubes), and of suitable stretch and recovery, i.e. elastic, properties in order to form a cover product that will be close-fitting, possibly require significant stretch properties at least for standard bulbs.
• Suitable materials were found to be silicone rubbers, such as cross linked with peroxide or addition cured say by means of a platinum based curing system, which further have the advantage of being non-toxic to human skin, are non-stick to glass, and have good colour-fastness.
• silicone rubbers such as cross linked with peroxide or addition cured say by means of a platinum based curing system
• one aspect of this invention is an elastic form-sustaining material in a shape and structure constituting a light-transmitting cover product capable of closely fitting, preferably with some degree of stretch, over the normal enclosure of a light device, and of a desired colour (though it may be uncoloured transparent or translucent where protection against shattering or weakening of the envelope is the prime interest).
• the preferred stretch can be very small in percentage terms but may be differential for some- bulb shapes. The only limitations for said stretching are, in fact, mechanical in terms of capability to fit the cover products to desired bulbs etc and in not imposing higher compressive forces than can be withstood by the bulb or tube enclosures.
• Typical products range from simple tubular sleeves for fluorescent tubes through tubes closed at one end for incandescent bulbs of so-called pigmy or candle type and dished covers for flared lamps such as reflective spot lamps etc to necked down balloon-like shapes for GLS lamps.
• Manufacture of such products by controlled laying of material onto suitable forms is doubtless- feasible, whether by an injection moulding process .or otherwise, but" any suitable process may be used.
• a 1 preferred manufacturing process uses injection moulding techniques modified to suit requirements of the product. Maintaining wall thickness for the covers of the invention is important particularly if differential wall thicknesses are to be achieved. Variations from derived thicknesses upto 0.1mm may be tolerated but above that are undesirable, as localised weakness or localised strong coloration may result.
• the preferred moulding machine uses an injection screw for forcing uncured material into the mould. A cold runner block is preferred so as to avoid curing of material that has not entered the mould. That with a slight vaccuum on the injection screw after ; introduction of a desired amount of material to the mould will inhibit curing of material that is just prior to the mould and hence reduce risks of blockage.
• Mouldable material is preferably forced into the mould at around 1000 psi. That, is low by comparison 0 with conventional injection moulding techniques that use around 20,000 psi but facilitates holding together of mould parts and hence keeps wall thicknesses within desired tolerances.
• Hardness preferably in the range of 30 to 50 international rubber hardness degrees (IRH).
• IRH international rubber hardness degrees
• High elongation at break such as 750+50% at 30 IRH or 400+50% at 50 IRH.
• High tear strength for example 75 + ION at 50 IRH or 25 IRH or 25 + ION at 30 IRH per standard test piece (BS Test 903).
• Minimum wall thickness for at least part of the covers of the invention may be 0.35 mm and preferably upto 0.60 mm-, especially upto 0.50 mm and more especially upto 0.45mm.
• Another aspect of this invention comprehends a light device- with a cover product of the irst aspect fitted over its normal enclosure in close contact therewith.
• a further aspect of this invention comprises the method or process of producing a coloured light device by fitting a stretchable cover product of the first aspect over the normal enclosure of a light device.
• Weather protection can be enhanced, particularly if the cover products hereof extend onto the metal lamp cap, say of an incandescent bulb, so as to seal against the rim of an entry to a festoon or other • type of lampholder.
• An alternative which is preferred at least for lamp enclosures that have much greater diameters than their caps, is for a subsidiary elastic sleeve-like product to butt up to, overlap onto, or be overlapped by, -the first-mentioned- cover product.
• a further alternative is for the basic cover product to extend or be capable of extension onto a lampholder, typically an entry neck of such a lampholder, or for a subsidiary sleeve-like- product to extend from over such a neck to over (or under) the basic cover.
• Figure 1 shows rough sketches of variant covers
• Figure 2 shows sketches of one cover and fitting to two small bulbs
• Figure 3 shows sketches of another cover and fitting to another lamp
• Figure 4 shows sketches of a further cover fitting to a further lamp and a related mould
• Figure 5 shows sketches of a standard lamp with cover and a mould
• Figure 6 shows sketches of a cap-like cover indicating fitting to a lamp
• Figure 7 shows sketches of tubular covers for fluorescent tubes
• Figures 8 and 9 show variants with extension to covering a festoon lampholder entry neck
• Figure 10 shows a lamp with an extended cover
• Figure 11 shows alternatives for a lamp and holder.
• incandescent lamp several types are shown specifically two designs of flared reflector type bulbs 10R, 10RS (also designated PAR 38 and DECOR SPOT as available commercially), a standard type of bulb 10L with a substantial globular part to its enclosure (designated
• GLS LAMP GLS LAMP
• IOC IOC
• the flared reflector type bulbs will usually be relatively large and are shown at 12R,
• FIG. 1 versatility of a single generally tubular cover product 12A is indicated in terms of fitting both to a small lamp 10PS of the type used for signs and known as pigmy sign, and to a small round enclosure lamp 10GR of the type known as golf round.
• the cover product 12A is indicated as being about 51 mm in length and of tapering diameter from about 18 mm just below its closed end to about 25 mm at its open end, and further of varying wall thicknesses along its length.
• the purpose of the latter is to reduce variation of perceived brightness of a covered lit-up bulb, though that is not found to be great for the particular material indicated above, typically being about 2% over a range of thickness of 0.38 mm to 0.75 mm. As shown, however, a closed end thickness of 0.38 mm from 0.45 mm over the next 13 mm, 0.6 mm over a medial 32 mm and 0.45 mm over 13 mm to the open end, is found to be satisfactory, at least for the two lamp types shown.
• Figures 3 and 4 shows variants (12B, 12D) on the cover products of Figure 2, effectively with same extended to about 76 mm and 88 mm length to fit larger candle, etc, type lamps 10CX, 10CY.
• Figure 4 also shows a mould 20D for the cover product 12D and is believed to be self-explanatory in terms of indicated thickness variations, also showing that the mould 20D will have a general slight flare to aid forming by injection moulding and release of its moulded cover product.
• Typical thickness tolerations range from plus 1 to 3 thou to minus 2 to 3 thou, and transitions will generally be smoothed/blended. A polished finish is preferred.
• Typical thickness tolerations range from plus 1 to 3 thou to minus 2 to 3 thou, and transitions will generally be smoothed/blended. A polished finish is preferred.
• a polished finish is preferred.
• cover products 12A, 12B will have different dimensions. .In all cases, those dimensions are to be considered as approximate and subject to alteration as may be required or desired. It is feasible to make witir a. small hole at the otherwise closed end if that assists moulding, and the indicated bead at the open end can. be very small or trimmed off if desired.
• Figure 5 shows a standard light bulb 10L and cover product 12L and corresponding mould 20L from which it will be seen that the cover product 12L is made to a shape quite close to that of the bulb but slightly less in diameter (by about 1/8 inch or 3 mm) to give a good close fit. Absence of any significant bead at the open: end of the cover product may facilitate fitting and removal of this type of cover.
• Figure 5 further shows a short elastic sle " eve 12S butting up to the open end of the cover product 10L and extending over onto the lamp cap 14 to an extent sufficient to make a resilient seal to edges 15 of the mouth of a festoon or other type of lampholder.
• FIG 6 the dished cover product 12R is shown in greater detail,. actually with a reverse-angled wall formation, to assist capture of the cover product 12R on the plain, usually pearled, end of • the reflector , type " bulb 10R.” Whilst the drawing indicates a thickness of only 10 thou (0.25 mm), greater thickness could be used if more convenient.
• Figure 7 shows two fluorescent tubes 10F, 10F' that differ as to their diameters, and related cover sleeves 12F, 12F' that are indicated as having the same nominal ' internal diameter as the external diameter of the fluorescent tubes. Little, if any, stretch is allowed for as friction could become great at fitting the sleeves to the tubes.
• a close fit is preferred, and that can be assured by suitable tolerance on sleeve manufacture being close and only negative from nominal. Whilst a thickness of 0.75 mm is indicated, other thicknesses could be used. Also, sleeving can be made in any convenient length and cut to desired sizes however and whenever required.
• a lamp bulb is shown fitted into a festoon lampholder with an extra long cover 12EL that extends beyond the entry neck of the lampholder.
• the alternative of Figure 9 shows a short cover 12SL on the lamp bulb and a neck cover 12N over the entry neck of the lampholder and under the lampcover 12SL.
• the neck cover 12N could be cut from tube as used for fluorescent tubes. It will be appreciated that other lamp bulb shapes can be similarly dealt with and that the extents of the neck and lamp covers of Figure 9 could be varied, as could overlapping or underlapping, even butting.
• a cover 112 for an ordinary lamp bulb 110 is extra long: in order to cover not only the glass enclosure 113 of the lamp but also a major part of the lamp cap 114.
• the cover 112 has different wall thicknesses in different areas. For example, its top part is approximately 0.5 mm thick its neck is approxi atley 0.6 mm thick, intermediate the top and neck i.e. around the widest part of the lamp is approximately 0.45 mm thick, nearer its open end about 1.00 mm thick but with an internal bead 117 about 1.5 mm thick.
• the different thicknesses allow for differential stretching requirements and the bead 117 reduces the risk of tearing of the cover.
• FIG. 11 two versions a cover 212 for a lamp 210 and lampholder 214 are shown.
• One version 212A of the cover extends onto the holder but the other version 212B extends to enclose a part of the holder.

Priority Applications (4)

Applications Claiming Priority (4)

Publications (1)

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ID=26291478

Family Applications (1)

Country Status (7)

Cited By (13)

Families Citing this family (1)

Citations (3)

• 1987
  • 1987-10-29 EP EP87907116A patent/EP0327570A1/en not_active Withdrawn
  • 1987-10-29 JP JP62506487A patent/JPH02500785A/ja active Pending
  • 1987-10-29 AU AU81552/87A patent/AU8155287A/en not_active Abandoned
  • 1987-10-29 WO PCT/GB1987/000768 patent/WO1988003327A1/en not_active Application Discontinuation
  • 1987-10-30 CA CA000550846A patent/CA1314528C/en not_active Expired - Fee Related
• 1988
  • 1988-06-30 KR KR1019880700765A patent/KR880701963A/ko not_active Application Discontinuation
• 1989
  • 1989-04-28 FI FI892040A patent/FI892040A/fi not_active Application Discontinuation

Patent Citations (3)

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