US 1653385 A
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3 2 ew m T aw E 11 BM w W G I E l Dec. 20, 1927.
. INVENTOR EUGENE W- BEGGS ATTORNEY Patented Dec. 20, 1927.
UNITED STATES PATENT OFFICE,
EUGENE WILLIAM BEGGS, OF GLEN RIDGE NEW JERSEY, ASSIGNOR TO WESTING- HOUSE LAMP COMPANY, A. CORPORATION OF PENNSYLVANIA.
Application filed November 16, 1923. Serial No. 675,063.
This invention relates to incandescent electric lamps and particularly lamps operated at a high temperature and utilized as light sources for projection apparatus.
An object of the invention is to guide a filament longitudinally and to prevent lateral movement thereof.
Another object of the invention is to provide a lamp filament with a guide memher, so arranged and associated with the filament, as to prevent rotation thereof during an operation of the filament as a light source.
Another object of the invention is to pro vide a lamp filament with a guide member adapted to permit movement of the filament longitudinally of the bulb and to prevent rotary movement of the filament within the bulb.
Other objects and advantages will be apparent as the description proceeds.
The present invention is particularly advantageous when embodied in a lamp of the high vattage type, as for example, lamps for use in motion picture projection machines.
Lamps tor the above purpose must obv' nisly provide a steady intense source of light. It is. therefore, essential that the filament or light source be properly maintained in a given relative position with respect to the other elements of the lamp.
Lamps tor the above purpose are usually provided with one or more coils ot suitable high resistance material, such as tungsten wire. and are suspended from rigid supporting members. During operation, the eX- tremely high temperature ot the coils results in an appreciable elongation thereof. The coils are usually arranged in pairs and in addition to the substantially longitudinal movement of the coils with respect tothe bulb, they also have a tendency to rotate about an external axis and it such rotation is permitted, the coils may make Contact, thus slrorhcircuiting and resulting in a burnout and a consequent termination of the life of the lamp. i
Inasmuch as it is necessary to permit a free movement of the filament. tor expansion and contraction, the present invention provides means for permitting such movement and for guiding the filament during the expansion action. The present'invention also prevents lateral movement of the filament during operation. Further ad vantage is attained inasmuch as the present invention provides a resilient support for the filament during transportation or other handling of the lamps, at which time they are subjected to jars and impacts which tend to disarrange the coils or cause them to break loose from their supports.
Although the present invention provides a means for guiding the filament in a given path, in addition to directing the longitudinal movement of the filament, the filament is maintained from rotary movement, thus the possibility of contacting coils is greatly reduced.
The invention may. comprise a lamp mount including a guide-member having one end securely fastened to a rigid portion of the mount or bulb with which the mount is incorporated. The opposite end of the said member may be looselyv connected to,
a portion of the filament wire. connecting one or more. coils. The said member may be of such construction as to provide a resilient portion at a suitable pointin its length and a lengthor section of the member between the resilient portion and the filament may move "freely with the filament in a substantially rectilinear path and may be so disposed that the longitudinal axis of the said section is parallel with the longitudinal axis of the bulb,
For example, the guide-member may be so connected to the filament, that under normal conditions, no tensional force is exerted upon the filament; that is, the resilient portion of the guide may be without internal tension until actuated by amovement of the filament when heated to ahigh temperature and by reason of the peculiar construction of the guide-member, the tendency of the filament to sag is greatly reduced. This is important, inasmuch as a constant pull in some types of lamps would impart av stress to the filament and add to the sagging action. which often destroys the usefulness of the filament. In other types of lamps, however, the guide may be disposed with an initial internal tension to compensate for opposing stress set up in a filament.
The present invention provides means to maintain the filament from rotation since one end of theguide-membermay be securely fastened to the lamp, a rotation of the filament, therefore, will tend to set up a torsional stress in the member. This stress, however, requires a force ot a inaguitude high enough to oppose a rotary movement of the filament and thus the filament is maintained in its proper position as a light source. 1
The present guide-member is particularly adapted tolamps in which the filament is burned at an extremelyhightemperature.
Tn lamps of the above character the first action of the filament, when broughtto incandescence is to expand longitudinally a distance which may bewlesignated as A. The heat generated by the filamentphowever, gradually raises the ten'iperaturc of i the supports upon which the filament is suspended' This heating results in an expansion of the supports :a distance-Which may be designated as i B. Anmlongatiou of the supports is, therefore, QlTGCiiflSlIlF sequent to the elongation of the filament.
It Will be understood that si ce the'guidemember is secured to the filament and to the mount independent of the supports, the dis tances A and B are in opposite directions With respectto the guide-member, therefore, in order to avoid stress Within the filament when in its most plastic state, the guidemember may be so arranged as to provide a force to move in the direction of either A. or 13 depending upon the lamp structure, i. e., thetype of lamp" to which the invention is applied.
The invention Will'be more fullyundeu stood by reference 'to' the accompanying drawings in Which i Fig. 1 is an elevational view or a mount for supporting a pluralityoii filaments in a pendent. position and illustrating an emhodiment er the invention;
Fig. 2 is a fragmentary view of a mount for supporting another form otfilament and. shows an application (it the present invention;
3 is a view takenon lineIII-III of Fig. 2;
Fig. 4C is a fragmentary view of a mount showing a multiplicity of'filaments and anapplication of the present invention therewith;
Fig. 5 shows the present invention applied to a pendant ribbon type of filament;
6 is a view taken on lineVL-VI of 5, and
7 is a perspective view of a guidemember.
A; mount of the type to which my invention' may be applied may comprise a flare tube '10 having the usual exhaust tube 11 and a pedestal or arbor l3 consolidated "portion 1.4a of the flare tube.
therewith. The several last mentioned parts may be of any electrically non-conductive material, such as.glass, and fused to gether at a compressed portion 14;. The mount may be sealed in any desired envelope or bulb 15, which is indicated in dotted lines in Fig. 1.
comparatively rigid lateral support men1- here 16 and 17 may be provided, the ends thereof being embedded in the compressed Leading-in conductors 18 and 19 may be connected to the embedded ends of the supports 16 and 17 respectively. The upper ends ol the sup port may be connected with a bridging member 20 of any suitable non-conductive material such as glass As illustrated in Fig. 1, a light source may comprise a filament 21 consisting of Wire Wound to provide a plurality of helicallengths or sections, four of such sections being employed in the type of mount shown in Fi l. The coiled sections are connected by relatively short lengths of non-coiled filament Wire bent to form loops 22, 23 and 242. The mount shown being of the pendant type, the coils of filament may be hung by means of their terminals 25 and 26 Which are welded or otherwise secured to the upper ends of the support members 16 and 17 respectively.
Additional suspension means may consist of a member 27 having a hook formed at one end and engaged With the loop 2 1: of the filament, the opposite end of the member 27 being secured to the non-conductive bridging member 20.
A filament suspended by the means just described may maintain a normal position if no forces are applied to move it from a given plane. It will be understood, however, that When electrical energy is passed through the filament and it becomes heated to the essential high temperature required to produce a light source, ccrtaii'i internal.
: t'orces due to expansion, contraction, elongation and crystal slip tend to move the filament from alignment Within the bulb 15. Also when lamps are tilted in operation, the force of gravity tends to distort the'filae ment.
For the purpose of maintaininn the lilament in proper relative position in opposition to the stresses set up during operation, the present invention provides guide-me1nbers 29 and 31. An end of each Of the guide-members may be embedded in the non-conductive pedestal 13 and thus firmly secured to a rigid portion of the mount. The opposite ends of the guide-members 29 and 31 may be provided with closed loops 32 and 33 respectively, attached to the loops 22 and: 23 ot the filan'ient. It will thus be evident that the guide-members 29 and 81 constitute anchors'or moorings to maintain ill) the filament in its proper relative position.
When providing a guide-member which will accommodate the expanding and contracting action of the filament, I have found that it is an advantage to provide, under certain conditions, a guide-member, which, although arranged to move with the filament and prevent lateral or other movement thereof, will be of such a character as to be adapted to normally impart a tensional stress to the coils which constitute the filament or normally retain the filament in a given path without imparting any initial stress thereto.
The guide-members may be of similar construction, and as'provided by my invention, each member may consist of a relatively stiff wire of rectilinear form throughout the greater portion or section 30 of its length. At a point in its length, however, preferably adjacent to its connection with the filament, I form the wire constituting the guide of V-shape so as to provide a pair of resilient members or arms 34". and 35 having their junction 36 off the axial line of the rectilinear section or sections of the guide. The section 30 of the guide is, however, preferably disposed with its longitudinal axis coincident with the longitudinal axis of a section'30of the guide between the resilient member 34; and the end of the guide attached to the filament 21.
The guide-members 29 and 31 are so disposed with relation to the filament, that when the ends of the guide-members are secured to the pedestal 13 and the other ends are secured to the filament, the resilient arms 34 and 35 may be disposed apart with a predetermined amount of gap or space 37 therebetween. It will be appreciated, therefore, that under normal conditions, the guide-members may connect the filament with the pedestal 13 without exertingauy tensional stress on the filament or a. slight tensional stress may be provided if desired. The guide members are self-supporting and the action of gravity does not become a factor in determining the amount of pull upon the filament when such pull is desirable. The construction of the guide-members, however, prevents lateral and rotational movement'of the filamentand maintains the filament in a given rectilinear path during expansion thereof when serving a light source and contraction when such service is terminated.
hen the filament is brought to incandescence during operation, the vertical expansive action thereof may, under certain conditions, tend to compress the resilient members or arms 34 and 35 together, which in turn, offer a certain amount ofopposition by reason of their resilient property. For example, as the coils elongate because of sag, there is a tendency to compress the arms 34 and 35 which oppose this sag; that is, the arms carry the weight to an increasing degree as the elongation progresses. Thus with a weak saggy filament, the support or guide will tend to reduce the sag.
It has been found, that a pair of coils, for instance those in Fig. 1, tend to twist or rotate about a vertical axis which may, as an example, be considered as disposed substantially between them. The guidemember, however, as provided by the present invention, opposes such rotary movement by reason of the torsional stress that would be set up in the relatively long straight portions or sections 30 of the guidemembers 29 and 31.
It has been found preferable to flatten the resilient members 34 and 35 in order to increase their resiliency in the direction desired and to provide for a distribution of material to oppose forces which tend to throw the filament out of alignment. It has been found preferable to flatten the arms 34; and 35 to a thickness less than the diameter or thickness of the sections 30 of the guidemembers.
The invention may be practiced with various other types of lamp mounts, for example, the type shown in Figs. 2 and 3 which employs only two coils for the filament 40, may be provided with a-single guide-member secured at one end in the upper portion of a stem press and the other end may be attached to a loop +11 which connects the coils.
The invention is also applicable to a lamp mountemnloying a multiplicity of coils 42 as shown in Fig. 4. This type of mount as used for stereopticon may be provided with three or more guide-n'iembers 29, 31 and 31 having their ends embedded in a pedestal and the upper ends attached to loops a l, l5 and 46. Figs. 5 and 6 of two light source elements con'iprising strips 47 and 48 bent to Zig-zag form. The strips may be suspended from support members 49 and 51 and provided with a cross-bar 52 welded on or otherwise secured to the lower ends of the filaments to span the space therebetween.
When the invention is applied to a mount having the ribbon type of filament, the guide-member may be secured by means of a loop 52 to a portion of the cross-bar intermediate the filaments.
By reason of the present construction, a mount is provided for effectively maintaining a filament in a given path, and an important advantage of my invention lies in its simplicity and the relatively low cost of construction.
It will be apparent from the foregoing, that the invention is applicable to various types of mounts and that the filament may be free to expend and contract through a given path which greatly reduces the warpmeanest ing on twisting 'aotion of I the filament to bring it without the desirable normal plane.
7 A unount embodying the present invention providesa light source which, when: in operation, gives a more uniformalight spot than is attained by the useof mountso'l' the ordinary construction.
oeil'though I have shown preferred embodiments of my invention, ait-isunderstood. that modifications may be made therein without departing fronti the invention as set forth in the. appended claims.
What is claimed is:
. 1. In an incandescent electriclamp mount, a coiled filament supported therefromin a pendent positiom-said filament being composed of several sections connected by sub stantially straightportions, means for conlining the movements ofsaid sections to-a predetermined path, saiduneans comprising guide members L including normally upper and.lowerv' straight-sections, the upper sections beingattached to the straight portions of the filament, the lower sections being secured to a rigid portion of the mount, each ofsaiduguides having flattened V-shuped resilient portions i proj ecting' radially: from the longitudinal axis of the mount to pre vent lateral; movement of said filament.
QQIn an incandescent electric lamp mount, a coiled filament supported therefrom in a pendent position, said filament being composed. of several sections connected by sub stantially straight portions, means for conlining thermovements of said sections to a predetermined path, said means comprising guide members including normally "upper and lowerstraight sections, the upper sections being attached to the straight portions ofthe filament, the lower sections being secured to a rigid portion of the 111OIlI1lZ,*Bt1Cl1 of said guides having fiat integral V-shaped resilient portions projecting: radially from the longitudinal. axis of the mount to pre vent lateral" movement of said filament.
' 3. Inqanincandescent electric lamp mount, a coiled filament supported therefrom in a pendent position, said filament being com posed ofseveral sections connected by sul 'stantially straight portions, means for confining' the movements of said sections to a F4. in an. incandescent electric lamp mount, a lightsource supported therefromin pend.- ent position, said. llgl1hSOllliCf-3 being composed of several filament-sections connected by substantially straight portions, means for confining the movement :of said filament sections to a predetermined path, said means comprising'a guide member having an upper-section and a lower-section, saiduppen section being attachedto a straight portion of said filamennthei lower-section being secured in a rigid portionv of said mount, fiat spring arms associated with said sections and .hav ing a fulcrum point oil the axial line of the guide member, saidiarms being connected at their fulcrum point, one of said arms being associated with the upper-section of said guide-member and the otherarm associated with the lowerrseotion of said guidemember to provide an intermediate resilient portion to compensate for the movement of thefilament when heated,
5. A mount for an incandescent electric lamp comprising a stem, supporting members extendingin an axial directioni therefrom, a filament consisting of a pluralityof coiled sections separated by relatively straight portions,said coiled sections being disposed substantially parallel and provided with terminal portions connected to the support members, guide members connected to straight portions ofvsaid filaments and to said stem, each of said, guide members hav ing portions intermediate their ends flattened and bent to V shape to provide pairs of resilient lever arms to oppose verticaland lateral movement of the sections of said filainent when heated and prevent sagging thereof.
6. Amount foran incandescentielectric lamp comprising a stem, supporting memhers extending,inapproximately anaxial direction. therefrom, a filament consisting-of a plurality of coiled sections separated by relatively straight portions, said coiled sect-ions being disposed substantially parallel and provided with terminal portions connected to the supporting members, guide members having normal upper sections attached to the lower straight portions of said filament and the lower-sections secured in the rigid portion of said mount, each of'said. guide members including a resilient bifurcated portion having the tines thereof flattened and" integral with? the respective upper and lower sections of each of said guides, said bifurcated portion being normally: positioned without internal tension. preparatory to offering opposition to the movement of a filament when heating to prevent sagging thereof.
In testimony whereof, I have hereunto subscribed my name this 14th day of Novemher, 1923.
.EUGENE WVILLIAM BEGGS.