Improvements in Holders for Electric Incandescent Lamps.
Year: 1899

page_text: [Communicated from abroad by ACTIENGESELLSCHAFT MIX & GENEST, Electrical
Engineers, of 67, Bulow Strasse, Berlin, W., in the Empire of Germany.]
Improvements in Holders for Electric Incandescent Lamps.
I, HERMANN OPPENHEIMER, Electrical Engineer, of 55, Redcross Street, Bar-
bican, London, E.C., in the County of Middlesex, do hereby declare the nature
of this invention to be as follows:-
The present invention relates to bayonet holders for high voltage, in which
the contact plates are arranged in such a manner that a secure connection between
the contact plates of the lamp and the plungers of the socket, is attained. A
further improvement is to be found in the fact that the distance between the two
poles is considerably increased whereby arcing is prevented.
By means of screws deeply sunk into a cylindrical china piece, there are fixed
two terminal plates. Immediately under same, two tubes with spiral springs and
plungers are fixed, the latter penetrating through the cylindrical hole in the
china insulating piece. The springy nature of the contact between the tube and
the plunger, is attained by making the tubes with small rims or lugs, which face
the contact plates, and which when the latter are screwed home, are pressing such
rims inwardly, thereby establishing intimate connection between tube and ter-
minal plate In each of the tubes there is a plunger which by means of a spiral
spring, is pressed against the collar of the insulating piece, and through such
plunger, contact with the lamp is established.
The spiral springs press furthermore the outer tube towards the contact plates,
and thereby increase the security of contact between the latter and the former.
The rim or lugs of the outer tube further serves the purpose to equalise certain
discrepancies in the height of the tube, or in the depth of the countersunk por-
tion of the insulating piece. The contact pieces are drilled cylindrically to allow
of the insertion of the flexible cords, and these latter are fixed by means of
terminal screws horizontally tapped into such contact piece.
In order to increase the distance between positive and negative poles, the china
insulating piece has got an S-shaped bridge encircling the contact plates, and
insulating same from the brass tube forming the socket for the lamp, and at the
same time separating both contact plates from each other.
To prevent arcing between the two plungers, the china insulating piece is deeply
grooved out in that part which lies between the two plungers. The holder itself
is finished in the usual style by having a brass top with nipple, or cord grip fixed
by means of a ring to the bayonet holder, in which latter the insulating piece
as described above is resting.
In order to guide the plungers it is advisable to insert between the tube and
the collar of the insulating piece a washer, only sufficiently large to allow the
plunger to pass through. Instead of tubes, with rims or lugs, it is also possible

page_text: to use a tube sealed at one end, which is pushed over the spiral spring and the
plunger, and which with the latter is by means of a contact plate, pressed down-
wards towards the collar in the china insulating piece.
Dated this Third day of August 1899.
Improvements in Holders for Electric Incandescent Lamps.
1, HERMANN OPPENHEIMER, Electrical Engineer, of 55, Redcross Street, Bar-
bican, London, E.C., in the County of Middlesex, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be par-
ticularly described and ascertained in and by the following statement:-
The present invention relates to.a bayonet holder for high voltage in which the
contact plates are arranged in such a manner that a secure connection between
the contact plates of the lamp and the plungers of the socket, is attained. A
further improvement is to be found in the fact that the distance between the two
poles is considerably increased, whereby arcing is prevented.
On the accompanying drawing, I shew in Fig. 1 the perpendicular section, in
Fig. 2 and 4 I shew the cylindrical china piece with its metal parts in front
and back view respectively, and in Fig. 3 a general view. Fig. 5 however shews a
sectional view of the china part alone, and Fig. 6 the china part without metal
piece, looking upon it downwardly, Fig. 7, 8, and 9 represent parts used in con-
nection therewith.
By means of screws bdeeply sunk into the cylindrical china piece a there are
fixed two terminal plates c (Fig. 2—4). Immediately under same 2 tubes f with
spiral springs and plungers g are fixed, the latter penetrating through the
cylindrical holes in the china insulating piece. The springy nature of the contact
between the tube, and the terminal plate is attained by making the tubes f with
small rims or lugs f which latter face the contact plates c. The contact plates
when screwed home are pressing against the tube, and their inwardly bent lugs
thereby establishing intimate connection betwen tube and terminal plate (Fig.
and 8).
C
In each of the tubes there is a plunger g (Fig. 9) which by means of a spiral
spring his pressed against the collar of the insulating piece, and through such
plunger contact with the lamp is established.
The spiral springs furthermore press the tube f towards the contact plates c
and thereby increase the security of contact between the latter and the former.
The inwardly bent lug f¹ of the tube f further serves the purpose to equalise
certain discrepancies in the length of the tube or in the depth of the counter-
sunk portion of the insulating piece.
The contact plates have cylindrically drilled holes 1 to allow of the insertion
of the flexible cord; and this latter is fixed by means of set screws laterally
tapped into such contact plates.
In order to increase the distance between positive and negative poles, the china
insulating piece has an S-shaped bridge m encircling the contact plates and
insulating same from the brass tube e, forming the socket for the lamp, and at
the same time separating both contact plates from each other.
To prevent arcing between the two plungers g, the china insulating piece has in
that part which faces the lamp, a deep groove n, and which lies between the 2
plungers. The holder itself is finished in the usual style by having a brass top d

page_text: with nipple or cord grip fixed by means of a ring o to the brass tube or socket e,
thus uniting all parts including the china piece .
In order to prevent the china piece from being shifted, the latter is provided on
opposite sides with 2 grooves into which fit the nicks of the top d, and the
indentations of the socket e respectively. As the plungers are situated on
that part of the insulating piece which faces the lamp, whereas the contact plates
are placed on the opposite side of such insulating piece, and furthermore as all
metal parts of opposite polarity are separated from each other by large insulating
surfaces, the whole bayonet socket is specially adapted for high voltage circuits.
In order to guide the plungers it is advisable to insert between the tube f
and the collar of the insulating piece i, a washer only sufficiently large to allow
the plunger to pass through. Instead of tubes with rims, or inwardly bent lugs f¹
it is also possible to use a tube sealed at one end, which is pushed over the spiral
spring hand the plunger g, and which with the latter is by means of the contact
plates c pressed downwardly towards the collar i of the china insulating piece.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is:-
1. A bayonet socket in which the plungers only are projecting on that part of
the insulating piece which faces the lamp. Such plungers and their contact
plates being constructed in accordance with and for the purpose as described.
2. A bayonet socket in which the insulating piece is provided with a cavity on
that part of it which faces the lamp, whereby the distance between the current-
carrying plungers is increased, thus preventing arcing, in accordance with and for
the purpose as specified.
3. A bayonet socket with an S-shaped bridge on the insulating piece in order
to increase the distance between the contact plates, and to prevent the possibility
of arcing, in accordance with and for the purpose as specified.
Dated this 4th day of May 1900.
HERMANN OPPENHEIMER.