Electric light fixture

Electric light fixture for the illumination of ovens of electric ranges characterized by a pot-shaped metallic mount insertable in a cut-out in an oven wall and holding a lamp socket, lamp and cover glass which can be screwed on to the front side of the fixture into said mounting and the mounting having a stop rim and holding members corresponding to the edge of the cut-out on its rearward side for the lamp socket which is held in position by resilient tabs and the light fixture being particularly characterized in that it can be mounted in position by a single person.

The present invention relates to an electric light fixture for the 
illumination of ovens of electric ranges, which comprises a pot-shaped 
metallic mounting part insertable in a cut-out in a wall of the oven and 
which furthermore holds a lamp socket and lamp and a cover glass which can 
be screwed on the front side of the fixture into said mounting part, the 
mounting part having a stop rim and holding members which correspond with 
the edge of the cut-out and on its rear a central cut-out for the lamp 
socket which is held by resilient tabs forming a part of the mounting 
part, the mounting part being furthermore provided on its wall with an 
internal thread and having over its entire extent a smaller diameter than 
the stop rim. 
This type of known light fixture is completely preassembled by the 
manufacturer and supplied together with an already inserted lamp to the 
consumer who then inserts the fixture into a corresponding cut-out in the 
receiving plate of the oven or the like from the front. Thereupon, the 
holding members, which are constructed as cut-out tabs and have also been 
pushed through the cut-out, are bent over from the rear in order to assure 
the fixture a firm seat in the cut-out. 
This fixture, which has some advantages due to the formation of the 
mounting part and holding members as a single piece, is difficult and 
inconvenient to mount since generally two persons are required for this 
purpose, one of whom inserts the fixture from the front into the cut-out 
which lies way back in the oven while the other bends the holding members 
over. Furthermore, the mounting part is expensive to manufacture since it 
is not possible to produce it in a follow-on tool and at least the thread 
must be applied by a second tool and the grounding connector must be 
separately applied subsequently. 
Based on the foregoing, the object of this invention is to create a light 
fixture of the above-described type which, while retaining the 
single-piece construction of mounting part and holding members, can be 
secured in position in the oven in a simple and easy manner by a single 
person and in connection with which the mounting part can be manufactured 
by a follow-on tool. 
In order to achieve this purpose, the invention proposes that the mounting 
part have, as holding members, a plurality of radially outwardly 
protruding spring tabs cut out towards the stop rim and laterally and 
uniformly distributed over the periphery, said tabs having at least a 
slightly greater curvature than corresponds to the curvature of the 
mounting part; that the spring tabs have noses which protrude laterally 
outwards on their free end towards the stop rim; that the stop rim is bent 
down towards the bottom of the mounting part; that screw threads are 
impressed radially only between the spring tabs, and that a resiliently 
pretensionable sealing ring of metal can be clamped between the stop rim 
and the cover glass, an axially extending, radially outwardly protruding 
rib being furthermore formed on the mounting part and adapted to be 
inserted into a groove in the cut-out as assurance against twisting. 
The manufacture of the mounting part of the light fixture is effected by a 
follow-on tool, the cutting and bending processes taking place in 
succession. 
The short thread is also impressed in this tool. 
The lamp socket is engaged by clamping into the mounting part, screwing in 
the lamp and screwing on the cover glass. The fixture is received 
pre-assembled in this manner by the consumer, who can insert it, solely 
with one person, into the cut-out in the oven, which is adapted to the 
circumference of the pot-shaped mounting part. For this purpose the cover 
glass is loosened, for which purpose a quarter of a revolution is 
sufficient, and pushed from the front into the cut-out in correct 
position. The spring tabs are initially pressed radially inward by the 
edges of the cut-out and then spring outwards under spring action after 
they have passed the edge of the cut-out. 
In order to prevent excessive outward springing and thus a spreading apart 
upon the tightening of the cover glass, noses are cut on the edge of the 
spring tab. The spring tabs can therefore only move out until the noses 
rest against the edge of the cut-out. The cover glass is now tightened 
again, the turning-lock preventing the mounting part from also being 
twisted and the sealing ring assuring an initial spring tension for the 
connection. The fixture is thus completely installed. 
In order that the sealing ring can be actuated without damaging the usually 
enamelled surface of the receiving plate, the sealing ring is provided 
with a radially extending surface, corresponding to a shoulder in the 
cover glass, which surface then passes into a slightly conical surface the 
free edge of which, resting against the clamping surface, is bent over in 
curved manner. 
In order to achieve a particularly good fit to the somewhat uneven 
enamelled surface, it is proposed that the sealing ring consist of 
aluminum. Similarly, other relatively soft or deformable materials can 
also be used. 
Since upon the cutting of the spring tabs and noses in ordinary manufacture 
a minimum free space of 2 mm is produced into which the edge of the 
receiving plate could possibly slide and thus interfere with the effective 
action of the noses, it is provided that the free cut between the stop rim 
and the noses of the spring tab is covered, at least approximately, by the 
curved collar of the stop rim. 
A preferred embodiment provides three spring tabs and between them screw 
threads corresponding approximately to the tab cut-out in their 
longitudinal length. In order to avoid the subsequent attachment of a 
grounding connector it is provided that in the bottom of the mounting part 
three spring tabs and a grounding connector are cut out and bent 
approximately at right angles outwardly in order to form the socket 
passage, the grounding connector, shaped as a flat connector, being bent 
twice at its end. 
Under certain circumstances it may be advantageous for the stop rim itself 
to be formed as a sealing ring.

According to the present invention, the electric light fixture for ovens of 
electric ranges and the like comprises a pot-shaped mounting part 1 made 
of sheet metal, a lamp socket 2 of ceramics, a lamp 3, a cover glass 4, 
and a sealing ring 5. The fixture is inserted into a cut-out in a wall 6 
of an oven in such a manner that the base part lies outside the oven and 
the fixture part extends inside the oven. The mounting part 1 has on its 
front a stop rim 7. Furthermore, there are uniformly distributed on the 
circumference of part 1 three spring tabs 8 which are cut free on their 
sides and towards the stop rim 7, which tabs are more greatly curved than 
corresponds to the curvature of the mounting part, as can clearly be noted 
from FIG. 2. The spring tabs 8 have noses 9 cut in them, which extend 
laterally outward towards the stop rim 7 at the free ends of the tabs. The 
stop rim 7 is bent downwardly towards the bottom 10 of the mounting part 1 
so that the free cut between the noses 9 and the metal plate above them, 
amounting to about 2 mm, is covered. 
Screw threads 11 in the form of short threads are impressed, at a distance 
form the spring tabs 8, in the region of the mounting part lying between 
the spring tabs 8. 
On the mounting part 1, a rib 12 is cut out on the edge of a spring cut-out 
and bent radially outward, and inserted in a corresponding rib of the 
cut-out of the wall 6 as assurance against twisting. 
In the bottom 10 of the mounting part three further spring tabs 8 are cut 
out and bent over as fastening elements for the lamp socket 2. Another 
spring tab is formed as grounding connector 14, its terminal end part 15 
being bent twice to form the flat connector (FIG. 1). 
Between the cover glass 4 and the wall 6 the sealing ring 5 is clamped 
which consists of aluminum and furthermore has a radially extending 
surface 16 which corresponds to the shoulder of the cover glass and passes 
into a slightly conical surface 17 the free edge 18 of which rests against 
the wall 6 and is bent over in a curve.