US2713630A

US2713630A - Floodlight with emergency quencher for incandescent lamp filament

Info

Publication number: US2713630A
Application number: US153218A
Authority: US
Inventors: Earl M Becker; John J Bridge
Original assignee: Mine Safety Appliances Co
Current assignee: MSA Safety Inc
Priority date: 1950-03-31
Filing date: 1950-03-31
Publication date: 1955-07-19
Anticipated expiration: 1972-07-19

Description

Ju y 1955 E. M. BECKER ET AL 2,713,630

F LIGHT WITH EMERGENCY QUENCHER INCANDESCENT LAMP FILAMENT Filed March 31, 1950 2 Sheets-Sheet l July 1955 E M. BECKER ET AL- 2,713,630

FLOODLIGi-IT WITH EMERGENCY QUENCHER FOR INCANDESCENT LAMP FILAMENT Filed March 31. 1950 2 Sheets-Sheet 2 I x J T I 3:33 x a? 12 2? 5 J5 IN V EN TORS bad FLQODLTGHT WITH EMERQEN CY QUENHER FUR El IQANDESQEr T lLAltiP FHLAR-QENT Earl M. Becker, Fittshnrgh, and .lohn .17. Bridge, Turtle Creek, Pa., assignors to Mine Safety Appliances Company, Pittsburgh, Pa., a corporation of Pennsylvania Application March 31, 195i), Serial No. 153,218 3 Claims. (Cl. 24t'l11.3)

This invention relates to the removal of heat from the filament of a broken incandescent lamp so that the filament will not ignite surroundnig explosive gas.

Occasionally, incandescent fioodlights and the like which are used in explosive atmospheres, such as found in coal mines, are broken accidentally. The filament of a piece or splinter of the bulb remaining attached to the stem of the lamp prevents the quencher from engaging the hot filament eifectively.

It is an object of this invention to provide in such a light a device of simple construction which insures that Most suitably, bulb. The side of the tially spaced points in by a bulb crusher that loop. The quencher and crusher are constantly urged toward the socket by spring means. Consequently, if the bulb is broken accidentally, the crusher will be redriving the lamp ahead the in stantthe bulb is broken, so that the circuit to the lamp will be broken and the time that it takes the quencher and filament to come together will be shortened.

The preferred embodiment of the invention is illus Fig. 3 is a fragmentary section, similar to Fig. 2, showing the quencher pressed against the filament of a broken lamp.

Referring to Figs. 1 and 2 of the drawings, a floodlight or spotlight case 1, adjustably mounted on the cover 2 of a battery box (not shown), contains a reflector 3 and has a lens 4 closing its front end. The lens and a sealing gasket 5 between it and the reflector are held in place by a retaining ring 6. The center of the reflector is provided with an opening, from which a rigid sleeve 7 projects backward into the case. Slidably mounted in this sleeve is the tubular liner 8 of an electric lamp socket 9 which is provided around the liner With an annular recess 1 that receives the sleeve. inside the back part of the socket liner is a pair of electric contacts 12, from which wires 13 tery box cover. The rear end of the socket has a rearwardly projecting bracket 14, in which a focusing screw 15, rotatably mounted in the back of the case, is threaded for adjusting the socket lengthwise of sleeve 7.

Rigidly mounted on top of the lamp socket is a tube 17 that extends loosely through an opening 18 in the reflector. The passage through this tube has an interior shoulder 19 which spaces a rod 20, that extends slidably through the tube, from the side wall of the passage. The rod projects from both ends of the tube. The rear end of the rod is round and carries a nut 22. The nut is urged away from an integral collar 23, which encircles the tube, by means of a coil spring 24 compressed between Most of the rod is rectangular in cross section so that it can not turn in shoulder 1'9, but for a short distance in front of nut 22 the rod has a cylindrical portion 25 for a purpose that will appear presently. The front The wire extends down below the rod in a vertical loop 26, which is substantially coaxial with the lamp socket behind it. This loop encircles and portion of the glass bulb 27 of an incandescent lamp, whose stem 23 is slidably mounted in socket liner 3. As the loop engages the bulb at a plurality of circumferentially spaced points in front of its greatest diameter or circumference, the coil spring 24, through the medium of the loop, presses the lamp back in the socket so that the usual electric contacts on the lamp will firmly engage socket T he Wire extends upward and forward from the rod and then down in front of the lamp. The wire is coiled around and supports a of suflicient mass to quickly remove brought into intimate engagement With each other. button is coaxial with the lamp socket, and preferably is spaced a short distance from the front of the lamp bulb. This spacing is maintained by engagement of the loop with the lamp bulb.

If the lens of the fioodlight is broken and the object that broke it, or a fragment of the lens, also breaks the lamp bulb.

its forward position. loop, however, appears in case some of the glass of the bulb remains projecting forward from the lamp stem and in engagement with the loop. Any such fragment e able to prevent loop 26 from moving rearward, because the rearward pressure of the loop will press the glass, which necessarily bows out behind the loop, inward toward the axis of the loop and thereby will break the glass. In other words, the loop will squeeze towards its center any fragments of glass remaining in engagement with it after the lamp has been broken. The result is that the loop serves to crush any portion of the broken lamp bulb that, otherwise, might prevent the loop from moving toward the socket. For best results, it is preferred that the crusher loop be substantially triangular in form so that it will engage the bulb at only three circumferentially and substantially equally spaced points. If it engages the bulb at more than three points, the pressure it exerts against the bulb at each point is reduced. Due to the fact that the quencher button initially is spaced from the bulb, it has an opportunity to acquire velocity before it reaches the point where any piece of glass could be.

[\t the moment the bulb is broken and the crusher loop is moved toward the socket by means of spring 24,

the quencher 33 is moved rearward simultaneously and 1 strikes and crushes the hot filament 34-, as shown in Fig. 3. The rod 20 moves backward in tube 17 until nut 22 strikes the back of the case 1. The smashing of the filament against the much cooler quencher button assures a considerable area of contact between them, so

that heat is removed from the filament instantly b-- fore explosive gas outside of the fioodlight can enter the lamp through the broken lens and reach the filament.

To further shorten the interval between the moment the glass bulb is broken and the instant the quencher strikes the filament, and also to prevent contact of the quencher with the filament from blowing the lamp fuse, the lamp stem is moved forward in the socket the instant the bulb is broken. This is accomplished by a coil spring 36 inside the socket liner. weaker than spring 24, normally is compressed between the inner end of the lamp and the back part of the socket. However, as soon as the lamp bulb is broken, spring 36 drives the lamp stem ahead at the same time that the quencher is driven back by the other spring. The moment the lamp is moved ahead in the socket, the electrical connection between the lamp and socket contacts 12 is broken, as shown in Fig. 3, so that there will be no short circuit that will blow the fuse. Engagement of nut 22 with the back of the case prevents spring 24 from driving the lamp stem back into the socket.

The broken bulb can be removed and replaced by a good one by pulling rod 20 forward far enough to position cylindrical portion 25 of the rod inside shoulder 19. The rod then can be rotated 180 and released. 7

The rectangular portion of the rod will be drawn back past shoulder 19 so that the rod can not turn back to its original position. While loop 26 and quencher 33 are pointed upward, the lamps can be changed.

It has been found that a floodlight or the like constructed in accordance with this invention always operates as intended when the bulb is broken. Sufficient heat is removed from the filament by means of the quencher This spring, which is to prevent the filament from igniting explosive atmosphere around the lamp. The quencher performs its function almost instantly, before any of the exposive atmosphere can reach the hot filament.

According to the provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. A fioodlight comprising an electric socket, an incandescent lamp mounted therein and provided with a filament enclosed in a glass bulb, a filament quencher disposed in front of the bulb, a bulb crusher engaging the side of the bulb at only three circumferentially spaced points in front of its maximum diameter, and spring means urging the quencher and crusher rearward to ward the socket, whereby if the bulb is broken accidentally the crusher will be moved rearward and the quencher will be driven against the lamp filament to quench it.

2. A floodlight comprising an electric socket, an incandescent lamp mounted therein and provided with a filament enclosed in a glass bulb, a filament quencher disposed in front of the bulb and spaced therefrom, a rigid loop surrounding the bulb and engaging the side of the bulb at only three circumferentially spaced points in front of its maximum diameter, a rod disposed beside the lamp and slidable lengthwise of the socket, the rod being rigidly connected to the quencher and loop, and a. spring urging the rod rearward, whereby if the bulb is broken accidentally the loop will be released and the rod will pull the quencher against the lamp filament to quench it.

3. A fioodlight comprising an electric socket, an in-- candescent lamp removably mounted therein and provided with a filament enclosed in a glass bulb, a filament quencher disposed in front of the bulb and spaced therefrom, a bulb crusher rigidly connected to the quencher and engaging the side of the bulb at only three circumferentially spaced points in front of its maximum diameter, and spring means for effecting relative movement of the quencher and lamp filament toward each other if the bulb is broken accidentally.

References fitted in the filc of this patent UNITED STATES PATENTS Lindbloom et al. June 24, 1941 Ceader May 28, 1946 Mines.