US1279807A - Swing-joint for lighting-fixtures. - Google Patents

Description

E. 0. WHITE.

SWING JOINT FOR LIGHTING FIXTURES.

APPLICATION FILED JUNE 3.1915.

1,279,807. Patented Sept. 24,1918.

Attest: Inventor: wq i/ by M Q I 1M Attys.

RS m. Pnomumm. WAsnmcmn. 01 k;

UNITED sT TEs TENT oEEIoE.

ERNEST 0. WHITE, or WEsTMoUNT, CANADA, AssIeNon, BY MESNE .AssIeNMENTs, To v DUPLEXALITE CORPORATION, OF NEW YORK, N. Y., A CORPORATION or NEW YORK.

Application filed June 3, 1915.

To all whom it may concern: I

Be it known that I, ERNEsT O. VVi-IITE, a citizen of the United States, residing at VVestmount, Canada, have invented certain new and useful Improvements in Swing- Joints for Lighting-FiXtures, of which the following is a specification, reference being had to the accompanying drawings, forming a part hereof.

In an application filed by the present ap-' plicant on March 31, 1915, Ser. No. 18,221, there is shown and described a lighting fixture in which there is provided a fixed source of lightand an invertible reflector, whereby the fixture may be converted from one in which the rays of light are thrown to the ceiling, as in the indirect lighting system, to one in which the rays of light are permitted to fall directly 011 the object, as in the direct lighting system. The present invention is concerned broadly with a fixture of this general type but seeks particularly to provide a convertible fixture which shall be peculiarly adapted for use under conditions where the other fixture, for some reason, is not desirable. In the present invention, the source of light is not fixed as before but is movable bodily with the invertible reflector during the conversionof the fixture for use in accordance with one or the other of the above named systems. The mere inversion of a reflector with its source of light is now well known and accordingly no claim is made broadly thereto. Known fixtures of this character, however, are maintained in normal position or in inverted position by means'of positive retaining devices which require especial manipulation by the user. Further, therelectrical wiring in such known fixtures as these has been subjected to abnormal twisting and bending strains or has required separate manipulation by the user to avoid such strains. These old structures are unsatisfactory principally inthe respects noted and the broad objects of the present invention, accordingly, are, first, to provide an invertible fixture in which the source of light is movable with the reflector and in whiehthe source of. light and the reflector are swung from normal position to inverted position about anaxis' coincident with the centerof gravity of the fixture and are, therefore, maintainedautomatically in the two extreme positions Without the aid of positive retaining devices; and second, to

Specification of Letters Patent.

. Patented Sept. 24,1918,

SeriaINo. 31,820. I I

incorporate in theswing joint of the fixture means whereby the wiring may be readily led to the source of light, will be readily accessible for purposes of inspection or repair andv will not besubjected to objection able twisting or bending strains during the rotation of the wires about the joint. These and other objects will be elaborated hereinafter in connection with the detailed description of the preferred embodiments of the invention appearing in the accompanying. drawings. In these drawings Figure 1 is a conventional view in elevation ofa fixtureconstructed in accordance with the invention, the reflector and source of light being indicated in inverted position bydotted lines. I

Fig. 2 1s a fragmentary detail view on a somewhat larger scale of the swing joint taken on the plane indicated by the lines 2-2 of Figs. 1 and 3 and looking in the direction of the arrows.

i Fig. 3 is a further detail view of the swing joint, partly in section, taken on the plane: indicated by the line 3-3 of Fig. 2 and looking in the direction of the arrows.

Fig. 4is a detail view in perspectiveof the sleeve into which the arms of the fixture extend;

1 Fig. 5 is a detail view in perspective of one of the collars which rest within the sleeve shown in Fig; 4.. i

Fig. 6 is a fragmentary detail View, partly in section, of a somewhat modified form of swing joint.

Referring particularly to Fig. 1, it will be seen that there are provided support/mg arms a on whichare carried swmg oints,

indicated generally at h, by which is formed a lunged connect1on between the arms a and the fixture arms 0 which carry the lamp socket 61, source of light 6 (illustrated as an incandescent bulb) and a, suitablev reflector the last named elements, of course, being movable together and as a' unitary structure about the swing joints Z) with 'the'fixt'ure corms. -It will be evident that when the parts are in what may be termed normal position,

that is, with the reflector as illustrated in full lines, the rays of light from the lamp 6 will be thrown upward to the ceiling or equivalent reflector from which they will be thrown on the objects to be lighted. .When the fixture armsc-swing about the swinging joint I) untilthe reflector 7 takes the position indicated in dotted lines in Fig. l, the fixture will become one of the direct lighting type and the rays of light from the source 6 will be thrown directly upon the object to be lighted. In accordance with the present invention, it is proposed to bring about the inversion of the reflector with the source of light by a construction which requires no special manipulation by the user, but which will facilitate the inversion by insuring that the fixture will be maintained automatically in its desired position. To this end, the axis 01' rotation of the fixture is coincident with the center of gravity of the swinging parts, so that no matter whether the fixture be in the position indicated in full lines in Fig. 1 or that indicated in dotted lines, the tendency will be to remain in that position and not move therefrom without the application of some little pressure. So far as concerns this first broad object of the invention, then, it is seen to reside in the provision of a balanced invertible lighting fixture. Of course, itwill be appreciated that in practice the tendency for the fixture to remain in any given position by reason of the coincidence of the center of gravity with the axis of swinging will be increased by the friction necessarily present in the joint. The presence of such friction, however, is merely incidental to the positioning secured by the balanced construction described.

The problem of providing an invertible lighting fixture which can be readily moved from one extreme position to another cannot be considered as completely solved in the absence of a suitable swinging joint to permit the rotative IHOVGIHODt of the fixture without injuriously affecting the electrical wiring. Accordingly, the second broad object of the invention. is to provide a swinging joint for fixture of the type referred to which shall permit the wiring to be led to the lamp with utmost facility, shall permit its inspection and repair, and shall guard against injury of the wire through undue twisting or bending strains imposed thereon during adjustment of the fixture. While the specific embodiment of the improved devices for attaining these purposes may vary, there has been illustrated in the drawings two practical embodiments of swing joints which have proved successful in use. In the first of these, shown in detail in Figs. 2 and 3, the arms a and c of the lighting fixture are disposed substantially parallel with respect to each other, respectively. A description of one of the joints will sufiice for both, it being understood that the axes of rotation of the two joints for any single fixture are coin cident. The ends of the arms a, c, extend through peripheral slots 9, g, respectively,

,formed in asleeve g and are threaded into scparatel bushings h which are preferably slotted, as 21th, to insure a frictional engagementbetween the outer wall thereof and. the inner wall of the sleeve gi -against which the bushings bear, as appears clearly in Fig. 3. It is not necessary that the bushings h be slotted, although this will usually be-desirable to hold the fixture against slight accidental movement from its desired balanced position. The insertion of the bushings it into the sleeve g can be effected readily by slightly compressing the bushings so that their tendency is to expand after they are in their positions. The sleeve g may have mounted therein a threaded stud i which may extend through the sleeve and maintain the coils of wire in substantially co-axial relationship with the axis of rotation and be retained co-axially in position with respect thereto by means of a nut 2". threaded thereon and further by means of cylindrical bosses i and 2' formed on the reverse faces of the head of the stud i and of the nut 2'', respectively. The head of the stud and the nut z" closethe open ends of the sleeve and so coverthe wires and form a sightly joint. The combined length ofthe two bushings h, when positioned within the sleeve. 5 is preferably less than the length of this sleeve so that the nut a" may be set up without engaging the bushings. The disposition and manner of securing the electrical wiring 7c in place in the swing joint so as to permit free rotation of the fixture thereabout can now be understood readily. This wiring is brought down through the hollow arm a and 1s coiled about the shank of the stud 2', the number of such coils depending somewhat upon the conditions of use and the character of the wire. After being thus coiled the wire is led down through the hollow arm a to the lamp socket (Z and afiixed to the electrode in a manner well. known. The important feature of this method ofwiring resides in the formation-of several coilstherein along the axis of rotation of the fixture, the result secured being that the total twisting or bending to which each coil is subjected is equal only to the normal bending to which a single 'coil would be subjected divided by the inunstandards the underwriters will not permit 'a conductor to be subjectedto abnormal 125 recurring strains which would have a haturaltendency to break down the insulation. Accordingly, if, a balanced invertible fixture of the type described is to be a practicalsuccess, a practical means for mounting the 0 wiring therein and permitting this rotative movement without in uring the WlI'lIlg must be employed.

In Fig. 6 there has been illustrated a somewhat modified form of a swing joint which will serve to emphasize the fact that the invention is not tobe limited to the specific constructions illustrated herein, but that the two broad objects stated in the preamble may be attained by modified constructions which are well within the scope of the axial relationship with respect to the axis of rotation, so that the electrical wiring is which leads down through the supporting arm a is, after being coiled around the shank of the stud I, led through the head of the tud and into the fixture arm C in a direction which is parallel to the axis of rotation. This construction, while bein somewhat simpler than that previously describedin that some of the parts are eliminated, has

the same advantages as those hereinbefore' pointed out in that it prevents undue twisting or bending strains being imposed on the electrical wiring, permits this wire to be led down through the arms of the fixture with great facility and permits the swing joint and the wire to be inspected readily and repaired through removal of the nut I.

In use, after assembling, the improved fixture may be supposed to be in some such position as illustrated in full lines in Fig. 1, in which the arms 0 form virtually extensions of the supporting arms a. The rays of light from the lamp 6 are thrown upward entirely by the inverted reflector If it is desired to convert the fixture into one of direct lighting, the user may, by exerting slight pressure on the fixture, cause the re- Hector 0 with the light 6 to rotate about the axes of the joints 5, the center of gravity of the swinging fixture being coincident with the axis of rotation, thereby insuring that the fixture shall remain in balanced position at all times and its rotation be opposed only by the friction in the joints 5. When the reflector f has been moved to its inverted position, as indicated in dotted lines in Fig. l, the rays of light are thrown downward entirely. The light and the reflector tend to remain in this inverted position by reason of the balanced condition of the fixture. During the swinging of the fixture from one extreme position to the other, the coils of the electric wire 70 which are disposed along the axis of rotation are not subjected to undue bending or twisting strains but are deflected to an unappreciable degree.

Permissible departures from the constructions illustrated have been indicated hereinbefore but the, scope of the invention will rial and tending to assume a larger diameter than the internal diameter of said case for frictional engagement therewith.

2. In combination with relatively swinging arms, a swing joint for lighting fixtures comprising a tubular case having a plurality of circumferential slots and a plurality of split tubes within the said case and connected through said slots with said arms respectively, the said split tubes being of resilient material and tending to assume a larger diameter than the internal diameter of said case for frictional engagement therewith, and a stud supported within the split tubes and adapted to support the electric wires for the fixture in coiled position.

3. A swing joint for lighting fixtures comprising a sleeve having slots formed in its periphery to receive the supporting arms 7 ERNEST ownrrn.

Copies of this patent may be'obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. i

Images