Patent Publication Number: US-3875443-A

Title: Incandescent lamp

Description:
United States Patent 1 in] 3,8 Nakamura [45] Apr. 1, 1975 [5 INCANDESCENT LAMP 3.244.926 4/1966 Eyer et al. 313/252 x 3.440.473 4/1969 Smith et al 3l3/273 X [75] Takes Japan 3.496.403 2/1970 Palermo et al 313/273 x Assignee: Matsushita Electronics Corporaion, PctcrSOn X Kadoma. Osaka Prefecture. FOREIGN PATENTS OR APPLICATIONS 35.4rs 1/1953 Poland 313/252 [22] Filed: Nov. 13, 1973 P b Alf d E S h v rimary &#39;xaminerre mit [211 App! 5 Assistant Examiner-Saxfleld Chatmon. .lr.  
 &#39; Attorney. Agent, or Firm-Craig &amp; Antonelli [52] US. Cl 3l3/274. 3l3/273. 3l3/275.  
  3 3 277 [57] ABSTRACT [51] int. Cl HOij l/96, HOij 19/50 in an incandescent lamp. particularly projection lamps [58] Field of Search 313/273, 274, 275, 276. of large luminosity, both ends of an upper glass bar for -3l3/277, 278 holding down supporting hooks, which hangingiy support segmented coils of an incandescent filament, are [56] References Cited welded to specified positions on the inner face of the UMTED STATES PATENTS bulb, so as to secure the filament rigidly and durably. 960.962 6/1910 Kuzel 313/277 X 4 Claims, 4 Drawing Figures INCANDESCENT LAMB BACKGROUND OF THE INVENTION This invention relates to an incandescent lamp, in particular to the supporting (propping) construction of its filament. Among such incandescent lamps. this invention concerns those for spot lighting or narrow beam projecting. especiallylamps of large luminosity.  
  For the incandescent lamp. it is very important. needless to say. that its incandescent filament must be rigidly and securely supported in its bulb. Sucha requirement is especially keen fora lamp which is designed for t a spotlighting. i.e.. for narrow beam projecting purposes.  
 lating bars bridging said leadin wires at their top ends and stem parts. respectively. Also. a specified number of supporting hooks are provided. each having one end embedded and fixed in said upper insulatingbar and the other hooked endhangingly holding the filament coils, in such a construction. however. for lamps of larger output and higher power. the filament must have an increasingly greater size and weight. and hence. it is necessary to proportionatelyenlarge the diameter of the two lead-in wires in order to prop the filament rigidly in the right position. Such enlarging of the diameter consequently invites mechanical and thermal weakening of the parts where said lead-in wires contact the inner glass face of the bulb. thereby hampering the manufacturing process. t  
 SUMMARY OF THE INVENTION struction wherein emission from the filament is not interrupted by the lead-in wires. i  
  A further object of this invention is to provide incandescent lamps of the above-described kinds embodying greater freedom&#39;in designing as small a means as possible for propping the filament inside the bulb. thereby making it possible to reduce the size of the bulbs.  
  In order to attain such objects as mentioned above. the present invention is characterized by fixing the upper insulating bar to the inner face of a bulb by welding. namely by heating. melting and thenconnecting. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a halogen projection lamp embodying the present invention; a  
  FIG. 2a is a front view partially in section of a halogen projection lamp embodying the present invention;  
  FIG. 2b is a side view partially in section of the lamp in H6. 2a; and  
  FIG. 3 is an exploded perspective view showing com ponent parts of ahalogen projection lamp embodying the present invention. for the purpose of explaining one method of theprocess of assembling the same. i  
 DETAILED DESCRlPTlON OF THE lNVENTlON FIG. 1 shows a halogen projection lamp. embodying the present invention. In FIG. 1 an enclosure 1 made of quartz glass encloses an incandescent filament 2. a  
  Moreover..the lead-in wires 3can be short and their. a upper ends need only hold the lower ends of the segf mented coils propped by the upper glass bar 7. Therepair of lead-in wires 3, and a filament supporting means 4.The enclosure 1 has a cylindrically shaped trunk portion which extends through a tapered part 21 and ends in a pair of tubes 6. The enclosure 1 further encloses amixture of argon gas and a specified quantity ofmethylene bromide and hydrogen bromide.  
 The filament 2 is made of a tungsten wire and formed into six segmented coils 5 which are arranged in a zigzag row on a level plane in such a manner&#39;that the axes of the coils are disposed substantially in parallel. The  
 pair of |ead-in wires 3. which feedsthe current in the quartz glass bar 7 disposed at right angles to the axis of the bulb and three supporting hooks 8 made of tungsten wires. one end of eachbeing embedded in and fixed to said upper glass bar 7. Both ends 9 and 9 of said upper glass bar 7 are welded on the inner face of the enclosure 1. The other ends of said supporting hooks 8 are bent up to hang&#39;down and engage upper spacers 10 which are the noncoiled parts formed between the segmented coils 5. The coils are also secured underneath at lower spacers by lower supporting hooks 15. The ends 11 and 11&#39; of the filament 2 are windingly connected to respective ends of linking wires 13 which 1.  
 are in turn wound on the respective lead-in wires 3 near their upper ends 12. The other ends of thelinking wires 13 are respectively fastened to a lower quartz glass bar 14, into which said lower supporting hooks l5 of tungsten wires are fixed. The lower supporting hookslS A pull down the lower spacers of the filament 2. The pair, of lead-in wires 3 need not be extended all the way along the filament assembly up to the upper glass bar as in the conventional projection lamp. but the lead-in wires 3 terminate slightly below the lower ends of the segmented coils 5.  
 As describedabove.the upward propping of the fila- L ment 2 is accomplished by the upper glass bar 7 firmly fixed to the upper portion of the inner face of the enclosure 1. Hence. the construction is very rigid and se cure. as well as strong against vibrations and shocks.  
 fore. the lead-in wires 3 dispense with the need of the conventional construction to rigidly support the heavy weight of filament. etc.. by long wires passing beside the filament. Accordingly. the lead-inwires can be much finer and shorter. and hence. the work required plified. FIG. 2 shows a for passing the lead-in wires 3 into the bulb can be simsecond example of the invention. In  
 FIG. 2 most of the parts are constructed in a similar 3 segmented coils 16 at both sides. namely. both ends of the filament coils 2 are formed as connecting coils l7 wound around and connected to the upper ends of the lead-in wires 3. A lower glass bar 14 is fixed to the mid dle part of the lead-in wires 3 which penetrate the glass bar 14. Theglass bar 14 has supporting books 15 supporting lower spacers 10&#39; of the filament 2. The parts of the lead-in wires 3 embedded in the lower glass bar 14 are slightly bent or have rugged surfaces in order to be firmly fixed. A base 18 is fixed to the stem part.  
 An actual example of the embodiment of FIG. 2, a.  
 halogen lamp of BKW/ 100V performance is as follows:  
 the diameter of the enclosure is 45 mm. and the length from the top to the bottom face of the base is 200 mm. The filament consists of six coil segments. each being wound for 26.5 turns of [.6 mm inner diameter and 1 mm pitch with 0.665 mm tungsten wire. The spacers length. The segments of the coilsare so arranged that.  
 the distance between the axes of the segments on both extreme sides (i.e.. the? axes of both outermost segments) is 25 mm. The upper and lower glass bars 7 and 14 are of roughly 6mm diameter and the supporting hooks 8 and 15 are of 0.7 mm diameter tungsten wire. The end spacers 111. may be connected to the upper ends of the lead-in wires 3 by placing their ends to ends contacting each other and continuously covered by connecting coils.  
  As a result of the above-mentioned construction. the lamp of the second examplehas the following advantages besides the advantages of the first example.  
 Since the upperends of the lead+in wires 3 are situ- 7 I ated coaxially with the segment coils 16 of the extreme sides of filament 2. thedistance between the two leadin wires 3 can be made very short. and consequently. the diameter of the enclosurecanbe made small. This ends of which are airtightly secured to the leading-in wires 3. The tapered part 21 is a short glass cylinder having an upper open end to be connected to the lower open end of the bulb 19. the upper open &#39;end of the tapered tube having a diameter just to fit inside the lower open end of the tube. The tapered part has two lower openings to be connected to the upper ends of the tubes 6, the lower openings having a diameter to fit out:  
 side the upper ends of the tubes 6.  
 The first step of assembling the lamp is to secure the upper glass bar 7 at a suitable location in the upper part ofthe bulb 19. The securing is made by holding the glass bar 7by ajig at a suitable position and heating the surface of the bulb at the position to be welded (melted and secured) by gas flames. and then by pressing the half-melted part of the bulb wall toward the ends of the glass bar 7.  
 The second step is to insert the filament assembly 20 it into the bulb and hang the spacers between segmented coils 5 of the filament 2 on the supporting books 8. Y  
  The third step is to cover the tubes 6 and filament assembly with the tapered part 21, and. to-seal the lower opening of the bulb l9 and the upper opening of the tapered part 21. and to seal the lower openings of the tapered part 21 and the upper part of the tubes 6. The sealings are made by heating and welding the parts to unite them to each other. i  
 The fourth step is to evacuatethe sealed bulb. injecting argon gas containing a specified small amount of methylene bromide, and sealingthe evacuation tube 22 by heating and pinching.  
 When desired, a base 18 is secured at the lower end i While I have shown and described several embodiments in accordancewith the present invention. it is understood that the same is not limited thereto but is susceptible of numerous changesand modifications as known to a person skilled in the art.&#39;and l therefore do i not wish to be limited to the detailsshow n and deis very advantageous as the halogen lamp in which the shielded or absorbedby the lead-in wires supporting the filament.-and can enjoy the resultant advantage of high efficiency of conversion.  
 electric power to luminous output The process of assembling or making the abovementioned lamps will be explained below with reference to FIG. 3. As shown in FIG. 3. which isan exploded perspective view of the lamp of FIG. 2. abulb 19. a glass bar I having several supporting hooks 8, a filament assembly 20 and a tapered part 21 are provided. The bulb 19 in a glass cylinder with an evacuation tube 22 at the top and with a broad lower opening. The upper glass bar7 is made by the process of at first, holding the fixed ends of the supporting hooks 8 between a pair of glass bars. and then heating and pressing the glass bar so that the two glass bars are united into one glass bar with the ends of the supporting hooks 8 embedded therein. The filament assembly comprises the filament 2, a pair of the lead-in wires 3, the glass bar 14 supported by the lead-in wires 3, the lower supporting hooks l5 fixed to the glass bar 14. and a pair of glass tubes 6, the lower scribed herein but intend to cover all such changes and modifications as are obvious to one of ordinary skill in What isclaimedis; t p 1. An incandesce&#39;nt lampcomprising a glassenclosure, i an incandescent filament enclosed in said glass enclosure. a pair of leadin wires extending through said glass enclosurefor feeding electricalcurrent to said filament. an upperglass bar having its ends welded to the innerface of said glass enclosure at one end thereof. a L  
 lower glass bar being secured in position within said &#34;glass enclosure at the other end thereof while having its.  
 ends left free from said glass enclosure. and supporting hooks extending between said upper glass bar and said filament and between said lower glass bar and said filamentfor supporting said filament in a desired position. 2.. An incandescent lamp as defined in claim 1 wherein the upper ends of said lead-in wires terminate below said filament.  
 3. An incandescent lamp defined inclaim. 2w  
 wherein said filament is formed into several segmented coils having their axes substantially parallel to the lamp axis. and the upperends of saidlead-in wires being situated coaxially with the outermost segmented coils of the filament.  
  4. An incandescent lamp as definedflin claim 3 wherein said lower glass bar is fixed by saidpair of leadin wires penetrating therethrough. 7  
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