US1640867A - Electric incandescent lamp - Google Patents

Description

Aug. 30,1927- H, woRKMAN ELECTRIC INCANDESCENT LAMP I Filed Feb. '7, 1923 Patented Aug. 30, 1927.

HAROLD WORKMAN, F GLASGOW, SCOTLAND.

ELECTRIC INCANDESCENT LAMP.

Application led February?, 1923, Serial No. 617,631, and in Great Britain July 5, 1922.

This invention relates to electric incandescent lamps and to lamp holders therefor. The principal object of the invention is to provide for the correct locating of the fila- 5 ment of an electric incandescent lamp in relation to its lamp holder or to an`optical reflector or lens system by which the light emitted from thelamp is directed and controlled. This invention is particularly apl0 plicable tov lamps used for light projection purposes and more particularly to motor car head lamps.

Electric incandescent filament lamps for signalling purposes are at present made sothat when the lamp is inserted in position in its holder the filament occupies the desired position in relation to the holder and reflector but in this case a special cap fitted with a long stem and a special lamp holder 2 are employed.

- In the case of motor car head lamps it is usually required to locate a closely wound type of filament correctly in relation to a reflector ofrparabolic or other form. It may be required for example to bring the axis of a pillar filament into line with lthe axis of the reflector, while bringing the ends of the filament within a prescribed range either in front or behind a focal point, or between 3o two foci in the case of a lamp having a reunderstood and readily carried into effect',

flector made-up in parts whose foci are at different points on the axis.

The present invention enables lamp bulbs fitted with caps of the usual type and with single, or double pole contacts, to be used in conjunction with lampholders provided ,with spring pressed terminals and at the same time enables the lamps to be adjustedy so that when `fitted in position in the lamp holders their filaments will be in the required position without any subsequent adjustment.

'To this end the invention mainly consists in an electric incandescent filament I 45 lamp bulb having a cap and single or double some examples of incandescent electric lamps furnished with fitting pieces" in accordance with the present invention are illustrated in the accompanying drawings, in which :-e

Figure 1 is an elevation of the lamp showing the fitting piece in section;

Figure 2 is a plan of Figure 1, with. the lamp bulb removed;

Figures 3 and 4 are similar views of a second form oflamp; while y Figure 5 is a view similar to Figure 1, of yet another form.

Referring first to Figures 1 and 2, a lamp a is shown having a cap b with the usual double pole contacts o, d. The fitting piece is in the form of a tubular ferrule e and is secured to the lamp cap b by an adhesive binding materia/l, in the actualv case illustrated, by solder which is seen at f. The ferrule e has its lower end of reduced diameterffor a short length so as to fit rather loosely upon the cap b, so that prior to securing the fer-.rule e to the cap b, the lamp as a whole and consequently the filament can be adjusted relatively to the ferrule in an axial direction and the lamp can be slightly swung relatively to the ferrule to adjust the position of the filament g until` it lies exactly in the axis of the ferrule e. The upper end 'of the ferrule e has lugs h, la, Z, of which the lug h is wider than the other two and these lugs serve for securing the lamp in the bayonet lamp holder. The form of lamp illustrated in Figures 1 and 2 is particularly adapted for use in a lamp holder, such as is illustrated in'Figures 1 to '7 of the drawings accompanying my patent application Serial No. 617,632, filed February 7, 1923. Such a lamp holder enables the advantages of the present invention to be fullyemployed because such alamp holder is arranged to be firmly fixed in its correct position relatively to a parabolic reflector or the like.

The bulb a and the fitting piece e are temporarily Aheld. in a suitable vfixture in which the bulb` can be adjusted along the axis of the fitting piece e and the filament can be swungvrelatively to that axis as already referred to. Then relative adjustment is carried out until the fitting occupies the desired position relatively to the 'lamp filament. The fitting piece e is then secured by n.

cement, solder or the like to the cap b. The lug h is made wider than or of a different shape from the other two lugs to ensure that the lamp shall be placed in the correct angular position in the lamp holder so that the terminals c, d shall register correctly wlth 'the contact studs of the lamp holder, as in.

this case, .double pole contacts are illustrated fitted in the lamp cap.

If desired the lower reduced end of the ferrule e may be made with holes or notches into or through which the solder f can ow |`illustrated is only 4:furnished with one con tact p arranged centrally. the other end of the filament being, of course. asis usual connected to the outer casing of the lamp cap b. A cap having double pole contacts could of course also be used with this form of fitting piece if desired. Further, in these figures, the reduced part of the ferrule e is at the end nearer the lamp bulb, so that the lugscor-V responding to la, lc, Z, are at the end of the i cap remote from the bulb a. v`Also instead of three lu s h, lo, Z, only two lugs m, n, are

rovide giving only a two point contact ut such contact extends over a sector shaped area at each side including an angle of almost .a right angle. Consequently the .form of lamp illustrated in Figures 3 and 4 can be more conveniently used, or example,

' with a lamp holder of the construction illustrated in Figures 14 and 15 of the drawings accom anying the specification of my patent ap ication Serial No. 617,632, filed February gth, l1923.

In Figure 5, another modification of the form of tting piece illustrated in Figure 1 is shown. The fitting piece is again in the form of a tubular ferrule e and has three horizontallugs near its upper endxof much the same shape. as the lugs h, lc, Z, in Figures 1 and 2. However, these lugs are formed by slittingv the ferrule e from its upper edge and turning down the lugs outwardly. The parts of the ferrule between the lugs are allowed to remain 'standing projecting up Wardly as seen at g, 1'. This construction has the advantage that these upstanding portions, part cylindrical in shape, can engage -with the internal interrupted flange of a' lamp holder, as illustrated in Figures 8 to 11 of the drawings accompanying the speciiication of my patent a plication Serial No. 617,632, filed February gth, 1923.

Although the invention has been described as applied to lamp bulbs for use in motor car head lam s, yet it will be obvious thvat it is also app icable to lamp bulbs and lamp holders for an .purpose re uiring accurate locating of a lamentk in re ation to an optical projection system. `A practical advantage of the invention is that the pole pieces as in ordinary lamp bulbs may be used for contact making purposes with ordinary spring terminals in the lamp holder,

ament mounted therein, a lampcap of usual constructions with 4a metallic casing secured to said bulb, a lamp contact carried in said lamp cap and a sleeve shaped tting piece formed to fit Within a lamp holder and having a part making annular contact with the outside of said lamp cap, said part having such narrow axial width that the lamp cap securing said tting piece to said lamp cap yis capable of rocking thereinand means for in a pre-determined position both axially and laterally with respect to said filament.

2. An electric incandescent lamp comprising in combination a bulb, a filament mounted therein, a lamp cap of usual construction secured to said bulb, a lamp contact carried in said lamp cap and a tubular fitting reduced at one end to fit loosely said lamp capand to form a resting place for solder by which said fitting piece is secured to said lamp cap in a pre-determined position both axially and laterally with reference to said filament.

3. An incandescent electric lamp comprising in combination a bulb, a lament mounted therein, a lamp cap of usual construction secured to said bulb, a lampl contact carried in said lamp cap and a tubular ttin l piece encircling said lamp cap formed wit outwardly turned lugs adjacent 'the end of the fitting piece nearest to the lamp bulb and reduced at the opposite' end to lit loosely said lamp cap and to lform a resting place for solder by means of which said fitting l piece, is secured to said lampcap in a predetermined position both axially and laterally with reference to said filament.

4. An electric incandescent lamp comprised therein, a lamp cap of usual constructi n secured in said bulb, a pair of lamp contacts carried in said lamp cap and a metallic tubular fitting piece formed at one end with three outwardly turned flat spaced lugs, one

ving in combination a bulb, a filament mou tbeing of different dimensions from the HAROLD woRKiniN.

and laterally with reierf4

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