1 PHN. 9187.
The invention relates to a capless elec-
tric incandescent lamp having a glass lamp envelope in
which a filament is accommodated and which is sealed by
means of a flat pinch in which current conductors are
incorporated, which conductors extend to the filament
and emanate from the lamp envelope at the end of the
pinch remote from the filament, said pinch having first
and second parallel major faces and two narrow side
faces, the current conductors being bent back along the
first major face and the second major face being connec-
ted to the narrow side faces vla respective inclined
side faces, the surface of the pinch having means to
cooperate with a fixing member of a lamp holder.
Such a lamp is disclosed in our Canadian
Patent 1,088,996 which issued orl November ~, 1980.
This known lamp may be used in an optical system in
which it is of importance tha-t, each time the lamp is
placed in a lamp holder, the filament should assume
substantially the same position with respect to a refer-
ence point. This is desired, for example, when the lampis used in a reflector, for example in a vehicle head-
light, in which case the reference point is the focus of
the reflector.
It has been found that the known lamp re-
quires a lamp holder having a fixing member which exerts
a comparatively large pressure on the pinch of the lamp. -
.~ ~
,L~ 'L
17 3 1979 z PHN. 9187
If this pressure is too low, -the lamp may assume an in-
clined posi-tion in the lamp ho:Lder by rotation about an
axis perpendicular to the major faces. In cases in which
the lamp envelope provides lit-tle grip, it may be cumber~
some to remove a spent lamp from the holder if the large
pressure required for ensuri.ng correct positioning is
exerted by the fixing member.
It is the objec-t of the invention to
provide a lamp by means of wh:ich an adequately accurate
locat:ion of -the f:ilament wi-th respec-t to a reference point
is read:ily and repeateclly obtainable on insertion of the
lamp i.n a larnp holder and which can also be easily placed
in and removed frorn the holder.
In ag:reement herewith the invention re].a-
tes to an elect:ric :incandescent larl1p of the kind ment:ioned:in tlle openi.ng paragraph ~ :ich :is character:ized :in tllat the
mealls to coopQrate with a fix:i.llg lllembe:r Or a lamp holcler
are provi.ded OIL the incl.:ined sicle faces of the p-inch.
~17 one embod:irtlent t]-lese means COlLs:ist of
a groove i.n eacll of the inc:l.ined s:icle :races provicled tralls-
vorse:ly l;o t]lC :I.orlg:it-llc1:ina:l. axiC; O:e t11e :Lall1p.
Irl <another embc)dirnent the inclined s:ide
- f`aces each have a respective rib thereon extending transver-
se]y to the longitl1dinal axis. However, it is alternati~rely
possib:Le to provide one inclined side face with a rib and
the other ~ith a groove, or providillg each of them, ~or
example, with a rib and a ~roove. The advantage O e grooves
is tha-t -they are less vulnerable to damage.
It has.been found that the lamp according
to the :invention combines the advantages of the l~n.own lamp,
an accurate defini-tion of the locat:ion of` the filament after
placing the lamp in a holder, with the advantag~e of a smal.1.
pressure exerted on the pinch by the fi~ing member and hen-
ce an easy exchangeability. .
Since the fix-ing members of the lamp.hol-
der for the lamp according to the inven-tion engage the in~
clined side faces of the pinch, they fu~fil a mu:l-tiple
fullcti.on:
(1) they exe:rt a p:ressure parallel to the major faccs of
'
..... ....... ,.. , .. . . . . , I
~,
28~
16.3.1979 3 PHN. 9187
the pinch so that the larnp is centred in the holder;
(2) they exert a pressure perpendicu:Lar to the major faces
so that the curren-t conductors o~ the larnp are pressed
against the electric contact of the lamp holder, and (3)
-they fix the height of the lamp in the lamp holder. As a
result of` this combinati.on of :iunctions, an extra member in
the lan1p holde:r :L`or press:ing the current conductors of the
lamp aga;.nst the electric contacts of the lamp holde:r may
in many cases be omitted.
I 10 The lan1p according to the invention may
: advan-tageously be constructed as a halogen incandescent
lamp in a hard gl.ass lamp envelope, for e~ample, of al]~ali
al.u1r1illoborosil:i.cclte g:lass havirlg a composi.-t:i.on of substan-
tlai.ly 77-81/~ by ~e:igllt S:iO2, 12-15~/o b~r weight B~03, 3-5.5
by weight Na?0 alld 1.5-2.5// by weight ~120~. Such a g].ass
has a coeffi.c:ient. of expens:ion o* 31-37 x 10 7 C
Embodi111erlts of the lamp according to the
invent:ioll are shown in the accompanyinf, d:rawi:ngs, of which:
.~:i.g. 1 :is a f:l"Oll'ii e:LevQt:i.o]l of a lalllp;
~i.g. 2 :is a si.de elevation of the same
lamp;
~ig. 3 is a cross-sec-t;ional view taken on
the line III-III of the lamp sllown in ~igs. 1 and 2;
Fig. l1 is a corresponding sectional view ;~
of a modif`ied embodiment of` tl~e lan1p of ~igs. 1 and 2 pla-
ced in a lamp ho:Lder which :i.s shown di.agrammatically;
~ ig. 5 is a front elevation of another
modified e1nbodi.ment of` a pi.nch; and
~ ig. 6 is a sectional view taken on the
line VI-VI of the p:i.nch shown in ~ig. 5.
In -these ~igu-res corresponding parts are
referred to by the san1e reference numerals.
In ~'igs. 1 and 2, referellce numeral 1 de-
notes a glass lamp enve:lope in which a fii.ament 2 is stret
35 ched and whicll i.s sealed by means of a`fla-t pinch 3 through
which cnrrent conductors 1~ and 5 extend to the filamcnt.
Tlle c1lrrent conduct;ors emanate at the en.d ~) of the plncll
remote f.ro1n l-he fi:Larme1ll 2. The current conduc-t;ors are bent ~:
I
c
~ 8~
16.3.1979 4 PHN. 9`187
bac~ along a first major face 7 (Ei.g. 2) of the pinch. The
curren-t conductors are each surrourlded there by a squeezed-
on nickel sleeve 18, 19 so as to ensure good corrosion-re--
sisten-t con-tacts.
Parallel to the first major face 7 the
pinch 3 has a second major face 8 and two Inutua:lly parallel
narrow si.de faces 9 and 10. Inclinecl side faces 11 and 12
connect the second major face 8 to the respective narrow
side faces 9 and 10. In the larnp shown. in l~igures 1 and 2,
the first major face 7 is also connec-ted to the narrow side
faces 9 and 10 via inclined side faces 13 and 14 (Eig. 3).
In each of the inclined side faces '1'1 and
12 grooves 15 and 16, respect:ively, are present, with which
a f:ixi.ng nlelnber o:E` a :lanlp holder Call cooperate. 17 denotes
t:hc :longitucl:inal ax:is of tlle :I.amp.
In ~:ig.3,~derlol:es the acllte angle wh:ich
the :inclined s:icle faces 'I 1 and 12 enclose w:i.th thc narrow
side :~aces 9 and 10, respe~c-tive:l.y, alld~derlotes t:he acute
allg:l.e wll-i.ch th~y enc.1.ose w:Ltll -the secol-ld nlcljor :~ace S.
2n ln E:i.~,~. 'I l;.ll~ llcl~.nlrOW ~S i.~ ;E`a.ces 9 ancl 10
i.rnlnecliaLely aclJo:in t}~e f:irst nlajor ~ace 7. I~o denotes the
housing of a lamp holder which has mutually insula-ted elec-
tric contacts 41 and 42. Eixillg members 43 and 44 wl~ich are
movable against resilient forces engage in grooves -l5 and
16, respec-tively~ fi.x the heigh-t of the .Lamp in the :lamp
ho:lder, hold the current conductors 18 and 1~ pressed
against the contacts 4l and 42, ànd centre the lamp in the
holder.
In Ejgs. 5 and 6 the pincll 3 comprises
30 ribs 20 and 21, respective:Ly, on its inclined side faces 11
and 12 for cooperation wi-tll a fixing Inelllber of a :larnp hol-
der.
EX~IPLE
A lamp having -the shape as sllowll in Eigs.
1 to 3 had a hard glass lalnp en~relope conslsting of 80. 5%
b~ wei.ght SiO2, 13% by weight B203 ~ 3 5% by ~e:~gllt Na~O~
2.3qO by weiglll ~1~03 and 0. 7qO by ~e;.gllt I20. Ou.-tside the
lamp enveloE~e the n~o:lybdenllln cur:rent. condnctors were
16.3.1979 5 ` PHN. 9187
enveloped by Q niclcel -tube and squeezed. The lamp envelope
was fi:l:Led Wi.t}l 7 bar kryp-ton to which 0 . 1% by volume
CH2Br2 had been added. The lamp consumed a power of 12 W at
6.75 V.
The inc:lined side faces of the pinch in
this lalnp enc]osed an angle~ of 30 wi-th the narro-w side
faces and an ang:le~ of 60 with the second major face 8.
.
.
.
.
