US2163673A - Lighting device - Google Patents

Description

June 27, 1939. L. F 'GARLOCK LIGHTING DEVICE Filed March 12, 1937 2 Sheets-Sheet l NVENTOR A 5W 5 F 43/?! 0g,

ATTORNEY June 27, 1939. GARLOCK 2,163,673

LIGHTING DEVICE Fi led March 12, 1937 2 Sheets-Sheet 2 M M -c148 ATTORNEY Patented June 27, 1939 UNITED STATES PATENT OFFICE LIGHTING DEVICE Application March 12, 1937, Serial No. 130,489

4 Claims.

' This invention relates generally to electric lighting apparatus and is more particularly directed to improvements in so-called electric safety lamps of the stationary or portable types. 5 While my invention, as will become manifest from the. following description, may be embodied in various forms of safety lamps of the stationary or so-called permanent types, for the purposes of this disclosure, I have elected to present it as it may be utilized in conjunction with lamps of the hand or portable types, designed to be employed in various locations and connectable at will to a suitable source of supply of electrical energy, through the medium of an appropriate 1 flexible electrical conductor. However, it will be understood that this is merely illustrative and is not to be construed in any sense as a limitation of the scope of use of my invention.

As is well known, safety lamps of existing designs are of a construction which render their use hazardous in many locations, even where great care is exercised in their handling. This is especially true, if the operation in which they are being employed is performed in an atmosphere in which volatile gases or gas fumes are present, either from seepage or otherwise. Obviously, the breakage of a light bulb or the production of a spark in the manipulation of the switching media of the device, or from faulty wir- 0 ing or loose terminal connections may have serious results. In fact, it is common knowledge that serious accidents and property losses have been caused by the ignition of explosive gases or gaseous fumes, by a spark produced in a portable lamp structure.

The failure of existing lamps may be attributed to the fact that either the light source, or the terminals therefor, are not hermetically sealed and explosive gases have more or less ready access thereto, with the result that explosions frequently occur at the point in the circuit where the make and break of the current is effected. This may be due to a loose connection, poor make and break of the switch parts or other causes.

Again, a spark may also be produced because of the character of the materials that enter into the construction of the lamp parts. They may not be of non-sparking or non-corroding forms, or if initially satisfactory in this regard, they may be so-constituted that rapid deterioration occurs.

Therefore, it is the primary object of this invention to provide a method and means of eliminating the potential hazards that are concomitant to the use of so-called safety lamps of the stationary and portable types that are now available in the market.

More specifically, it is an object of this invention to provide an electric safety lamp, wherein all elements thereof, designed to function in an electrical circuit are protected from the external atmosphere and volatile gases or gaseous fumes with which it may be surcharged or laden, thereby materially increasing the field of utility of such apparatus, and, at the same time, adding to its efficiency and all around serviceability.

It is also an object of this invention to provide a safety lamp of the hand or portable type, which is sturdy in construction, light in weight and foolproof in operation. 15,-

Another object is the provision of a safety lamp, so designed that any explosive gas must pass through at least two sealed compartments before arriving at the point of electrical circuit where the make and break of the current occurs 20 or is effected.

Other important objectives of this invention are; to prevent the use of the lamp Without a protective globe or guard being in place; to prevent loose globes and also reduce globe breakage 25 by supporting the globe at both ends; to dissipate heat through contact of the guard and globe; to make the globe holder and handle of material which is a non-conductor, unbreakable and unaffected by oil, grease, solvents, acids or alkalies.

Further objects of the invention will become manifest asv the description proceeds and I would have it understood that I reserve unto myself all rights to the full range of equivalents, both in structure and in avenues of use to which I may be 5 entitled under my invention in its broadest aspect.

In the accompanying drawings, I have illustrated a preferred embodiment of my invention.

However, it may take other forms within the purview of the appended claims.

In the drawings:

Figure l. is an elevational view of a portable lamp conforming to my invention.

Figure 2 is a sectional view, taken on the line 45. 1-1 of the preceding figure.

Figure 3 is a cross-section of the handle, showing the strain relief clamp, and taken on the line IIII]I[ of Figure 2.

Figure 4 is a top plan view, partly in section, 5 of the globe holder and handle.

Figure 5 is a vertical section, on the line IVIV of Figure 4.

Figure 6 is a transverse section taken on the line V-V of Figure 5; and

Figure '7 is an exploded View of the lamp socket and associated parts shown in Figure 5.

Referring now to the drawings in detail, in which like characters of reference are employed to designate similar parts in the several views, the three main assembly parts are a globe I, a holder or mounting 2 therefor and a handle or grip 3. A feature of the globe I is that it is not formed with threads but is held firmly in place by and between a metal pad 4 carried at the top of the metallic guard 5 and a relatively thick resilient gasket 6 positioned in the base of a circumferential groove or recess 2a formed in the holder 2. The guard 5 may be of the conventional basket type having intersecting ribs 1' some of which emanate from a flanged base I provided with internally formed threads Illa adapted to mesh with complemental external threads on the holder 2. The retaining pressure on the globe I is obtained by screwing the guard into the holder 2, the metal pad 4 thus being urged into contact with the upper part of the globe and causing the lower end of said globe to firmly engage and seat upon the gasket 6. The mounting of the pad may beeifected by countersinking a screw 8 into the inverted surface of the pad, the screw being adapted to engage suitable threads formed in a depending lug 9 formed integral with the guard. For convenience, in using the lamp, a hook II is provided, the latter being attached to the guard by threads formed on the shank of the hook engaging a threaded recess in the top of said lug 9.

This method of supporting the globe I at both ends, obviously, greatly lessens the liability of lamp and globe breakage, thus making for greater safety and reduced maintenance costs. Further, the metallic pad 4 in contact with the top of the globe, also functions to conduct the heat from the globe to the ribs of the guard for dissipation into the atmosphere. The absence of threads on the globe, of course, eliminates starting points for cracks and breaks.

The globe gasket 6 is of the so-called split cup type and is resiliently held in place within the aforesaid groove or recess 2a by the inverted metallic cup or bridge piece I3, the flange I30,

of which is entered therein, as shown in Figure 2, the said bridge, which is provided with a central opening, being fastened by screws I4 to a nonconducting socket member I5, with which said opening is alined.

The said socket I is formed with an external projection or key I5a, which is adapted to register with a groove I50 in the inner wall of the mounting or holder 2, to restrain said socket from rotative movement relatively to the mounting, the socket and the opposed wall of the mounting being complementally tapered to obtain a snug fit when the guard 5 is screwed home with the globe I in place, for the reasons, which, hereinafter, will become apparent. As will be seen, the socket also embodies the conventional threaded metallic shell I2 for the reception of the lamp Ia, which is connected to the customary outer terminal I6, overlapping the base thereof and held in place by the screw Il engaged in a threaded aperture in the washer I8, the latter being fixed to the socket base by a second screw Ila. To appreciate more clearly the mounting of the socket I5, reference should be had to Figure 7.

The washer I8 is seated in one end of a flexible metallic bushing of the socalled bellows type, as indicated at 20, the terminal sections thereof being cupped to receive the washer I8, as aforesaid, and a correspondingbottom washer I9.

A center contact-making pin 2| is reciprocally mounted in telescoping sleeves 22 and 23. Compression springs 24 and 25, housed within said sleeves respectively, normally maintain the pin 2| in position to contact with a center contact plate 26 secured by screws 29 centrally of the base of the socket I5. A coil spring 4|, contained within the bushing 20, with one of its ends abutting against the washer I8 and the other against the washer I9, normally maintains said bushing in an expanded condition, as shown in Figure 5, with the pin 2! out of engagement with the con tact plate 26. However, by placing the coil spring 4i under sufficient compression, as more fully described hereinafter, the bushing is compressed in opposition to the spring 4! to a point where the contact pin engages, in a yielding manner, the contact plate 26, thereby completing the circuit through the socket terminals.

As will be observed, the spring 24 is interposed between the sleeves 22 and 23, while the upper end of the spring 25 bears against the head of the pin 2I with its lower end disposed within the cup-like member 21 threaded into the lower end of the sleeve 23, a screw 27a, adapted to contact with said member 27, is supported from the insulator piece 42, in juxtaposition to the lower end of the sleeve 23, carrying a contact finger 28-, the said piece G2, rectangular in configuration, being mounted transversely of the base 30 and functioning as a spacer for the lead-in wires. base 39 is of non-conductive material and embodies threaded metallic sleeves 3I-3Ia. which accommodate the usual terminal screws 323Za, to which the lead-in Wires, indicated at a and b, are fastened, the aforesaid contact finger 28 being connected to the terminal screw 32, as shown in Figure 2.

From the structure thus far described, it will be evident that when the globe I is removed, or the guard partly unscrewed, the expansion of the spring M and of the bushing 20, under the influence of said spring, produces a switching action which interrupts the fiow ofcurrent through the socket I5, by breaking the contact between the pin 2! and the plate 26, the switching action occurring within an hermetically sealed enclosure or chamber, thus eliminating the possibility of a spark, which may result from the make and break of contact, causing an explosion, as often occurs where portable lamps of existing types, with their unprotected switch mechanisms, are used in locations where explosive gases are present. As will be apparent, the gasket 6, in conjunction with the bridge IS, the socket I5 and the associated flexible bushing 20, cooperate in the formation of the sealed. enclosure, within which the switch elements function solely in response to the rotative movement of the guard in one direction or the other, the globe, as engaged with the gasket 6, when the lamp is in circuit, forming an hermetically sealed chamber therefor.

The electric cord or cable 33 is admitted to the bottom of the handle 3 by passing it through a rubber bushing 43, carrying a strain relief clamp 34, said bushing being secured intermediate the cap 35, threaded in the end of the handle, and a stuffing box formed by a, cored tapered plug 36 engaging an adjacent complementary wall section of said handle.

As will be noted, the bushing 43 has longitudinally spaced shoulders, one of which abuts against said plug 36 and the other against the cap. 35. Thus, by screwing in the cap 35, the plug 36 is forced to a tight fit or seat, providing Said a sealed compartment in the handle 3, for housing the exposed ends of the cable 33. Since no gases can enter this sealed compartment, it is obvious that a possible loose connection at one or the other ternn'nal points, or both, can cause no damage.

It will be apparent from the foregoing description, that to remove the globe l and thus break the seal of the enclosure. it is necessary to turn or unscrew the guard 5, the action of the switch elements being such that a complete break of the circuit is effected before the seal of the switching enclosure is broken. Also, as will be noted, since the globe controls the switch mechanism, the lamp cannot be used Without the globe; neither can the fixture be used as an outlet for other electrical apparatus. In case the lamp is broken within the globe, it remains sealed until the switching mechanism is actuated to interrupt the circuit by the removal of the globe. It further will be seen that loss of the globe gasket 6, or its omission in putting on the globe, is prevented by the fact that it is virtually interlocked with the socket l5, through the medium of the bridge I3. The strain relief clamp in the handle, of course, prevents the electric cable from twisting.

By carefully selecting the materials from which the components of the portable are made, the life and general utility of the apparatus may be enlarged. For instance, by making the guard of an aluminum alloy, light weight and nonsparking characteristics are obtained. The globe holder or mounting may be made of any suitable composition. Tufiite which is a non-conductor, light in weight, unbreakable and unaffected by oils, greases, solvents, acids or alkalies, and is non-combustible and a poor conductor of heat, I have found responds admirably to the requirements of my invention.

As will be manifest, the switching mechanism of my invention and the form of enclosure therefor described, may be incorporated in a wall, ceiling or other permanent lighting fixture, utilizing a guard of appropriate design to function in the manner of the guard of the portable apparatus, or the same results may be obtained by employing the globe itself as the switch mechanism actuating medium, the globe in such case being formed with threads for engagement with those of the mounting, which, of course, may be of any preferred or requisite design to attain the objectives of this invention, as hereinbefore set forth.

Various changes in the structural details and in the arrangement of the cooperating elements of my invention may be made and other materials than those specified may be used, without departing from the spirit and scope of disclosure, as will be evident to one skilled in the art to which this invention appertains.

I claim:

1. A portable electric safety lamp having a plurality of separate sealed compartments, one of said compartments being the space enclosed by a globe supported at the top and bottom thereof, a second compartment being a space within the handle provided with terminals for lead-in wires and the third being a flexible bushing of the bellows type intermediate of the other compartments and switching members for making and breaking the electric circuit through a lamp contained within such globe, enclosed within said bushing.

2. In a portable electric safety lamp, a switching mechanism, comprising a socket member supported by a flexible bushing, said bushing housing contact members for establishing a circuitthrough a lamp inserted in said socket, said members including a pin reciprocally mounted in spring-actuated telescoping sleeves, said pin being adapted to engage a central contact of said socket when said springs are under tension and to disengage said contact when said springs are relieved of tension.

3. In an electric safety lamp, a switching mechanism comprising a socket member carrying a resilient flanged metal cup, a cupped gasket mounted thereon, said gasket being supported by a flanged bushing having make'and break members for establishing a circuit through a lamp inserted in said socket, the closure of the circuit being effected by exerting pressure on said bushing and the rupture of the circuit being effected by removing such pressure, said switching operation being accomplished without exposing the switching mechanism to the atmosphere.

4. A lighting device embodying an electric lamp, a socket therefor, an enclosure for said lamp, a mounting for said enclosure, said socket being contained within said mounting, an expansible and contractible chamber within said mounting, switch mechanism wholly contained within said chamber and means for hermetically sealing said chamber, said sealing means being functioned solely by the rotative movement of said enclosure on said mounting.

LEWIS F. GARLOCK.

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