Air- and Water-tight Telegraph Transmitter Keys for Use in Mines and other Exposed Places.
Year: 1899

page_text: Date of Application, 13th Oct., 1899
Complete Specification Left, 12th July, 1900-Accepted, 22nd Sept., 1900
[Communicated from abroad by ACTIEN-GESELLSCHAFT, MIX & GENEST, Electrical
Engineers, 67, Bulow Strasse, Berlin, W., in the German Empire.]
Air- and Water-tight Telegraph Transmitter Keys for Use in Mines
and other Exposed Places.
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:-
Tapper keys or plunger Morse contacts used in mines and railways are sub-
jected to very rough usage, and consequently their construction must be of the
most solid and substantial character in order to withstand such unceremonial
handling. It is further essential that they should be protected against the influ-
ences of dampness or water generally, and as far as mines are concerned, also
being made air and gas proof.
The invention described hereafter aims at fulfilling these requirements. The
plunger Morse contact consists of a circular cast iron base which on its surface
has a circular groove sufficiently large to accomodate half the thickness of a
paratin cord. The cover fitting to the top of the base has a rim corresponding
with the groove in the base and accomodating the other half of the paraffinned.
cord so that when the cover is screwed home to the base, the rim presses against
the cord, making the joint between cover and base impermeable. The centre
of the cover is more heavily cast, both inside and outside, and a hole being drilled
through allows the plunger to be inserted. Such plunger is insulated on its
lower part, and touches the arm of a lever. A flange surrounds the plunger inside
the cover, and a hood-shaped handle is fixed to that part of the plunger which
projects beyond the cover. The hood-shaped handle also serves as a protection
against moisture.
That part of the plunger which moves within the centre opening of the cover
is partly grooved out, the groove being filled with paraffinned threads, thus
making the aperture water-tight.
Insulated from the base, but fixed to same, are the bearings for the axis,
over which is pushed a tube, and to such tube is fixed the lever arm, which on its
free end carries the contact spring. A spiral spring encircling the tube and fixed
with one end to same, and with the other end to the lever arm, holds the lever
arm and spring in a slanting position. A terminal is also fixed to the insulated
part of the bearings, and serves to accomodate one pole of the battery.
The tendency of the spiral spring to pull the lever upwards is counteracted
by an angle-piece fixed opposite the bearings, and facing with a contact screw
the free end of the contact spring on the lever, so that in its normal position the
contact spring touches against the contact screw of the angle piece referred to.
Such angle piece which is fixed to the cast iron base and insulated therefrom,
carries also a terminal for the second pole of the battery.

page_text: Underneath the arm of the angle piece is fixed to the base and insulated
therefrom, a second contact screw and plate, which latter carries another ter-
minal to accomodate a second circuit. If the plunger is now pressed down-
wards, it moves the lever arm, and with it the contact spring from its normal
position, and the spring is thereby pressed towards the second contact point, thus
interrupting the first and closing the second circuit.
Dated this 12th day of October 1899.
2
COMPLETE SPECIFICATION.
.19.
is
Air and Water-tight Telegraph Transmitter Keys for Use in Mines
and other Exposed Places.
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 and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
-
Tapper keys or plunger Morse contacts used in mines and railways are sub-
jected to very rough usage, and consequently their construction must be of the
most solid and substantial character in order to withstand such unceremonious
handling. It is further essential that they should be protected against the influ-
ences of dampness or water generally, and as far as mines are concerned, also
being made air and gas proof.
The invention described hereafter aims at fulfilling these requirements. On
accompanying drawing I shew in Fig. 1 a Morse contact in plan with the top of
the cover removed. In Fig. 2 a section with cover on, as indicated by the
lines w, z, and x, y, respectively of the Fig. 1.
The plunger Morse contact consists of a circular cast iron base b which on its
surface has a circular groove & sufficiently large to accomodate half the thick-
ness of paraffinned cord e. The cover a fitting to the top of the base has a rim c
corresponding with the groove d in the base and accomodating the other half
of the paraffin cord e so that when the cover a is screwed home to the base, the
rim c presses against the cord e making the joint between cover and base imper-
meable. The centre of the cover a is more heavily cast at f both inside and
outside, and a hole being drilled through, allows the plunger g to be inserted.
Such plunger g is insulated on its lower part h, and touches the arm of a lever i.
A flange surrounds the plunger inside the cover, and a hood-shaped handle ¹
is fixed to that part of the plunger which projects beyond the cover.
The hood-
shaped handle also serves as a protection against moisture from above.
That part of the plunger g which moves within the centre opening of the
cover is partly grooved out at 7, the groove being filled with paraffinned threads,
thus making the aperture water-tight.
Insulated from the base but fixed to same, are the bearings for the axis p
over which is pushed a tube n, and to such tube is fixed the lever arm i which
on its free end carries the contact spring m. The circuit both for open and
closed batteries is closed by means of a spring m which is, as already explained,
fixed to the free end of the lever i.
A spiral spring'q encircling the tube and fixed with one end to same, and with
the other end to the lever arm, holds the lever arm and spring in a slanting
position. A terminal is also fixed to the insulated part of the bearings, and
serves to accomodate one pole of the battery.
The tendency of the spiral spring to pull the lever upwards is counteracted by

page_text: an angle-piece r fixed opposite the bearings and facing with a contact screw r¹ the
free end of the contact spring m on the lever i so that in its normal position
the contact spring m touches against the contact screw of the angle piece
referred to. Such angle piece which is fixed to the cast iron base and insulated
therefrom, carries also a terminals for the second pole of the battery.
Underneath the arm of the angle piece is fixed to the base and insulated there-
from a second contact screws and plate, which latter carries another terminal s
to accomodate a second circuit. If the plunger is now pressed downwards, it
moves the lever arm, and with it the contact spring from its normal position,
and the spring is thereby pressed towards the second contact point s¹, thus inter-
rupting the first and closing the second circuit.
As the plunger g is constructed like a stuffing box, neither fumes, gases, or
dampness, have access to same, and consequently both when at rest or when
pushed down it is practically impermeable.
The construction as described above could easily be converted into a pull by
elongating the tube n, allowing same to penetrate through the cover a and
arranging the opening through which it penetrates as a stuffing box in a similar
manner to what the plunger is arranged. To the free end that is protruding
from the cover, a chain may then be attached, thus making it a pull instead of
a push.
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 water, air, and gas proof contact in which the contact making parts are
mounted within an air and water proof cover, while the plunger or elongated
axis acting upon the contact making parts are arranged in a stuffing box manner,
fully as described and for the purpose set forth.
2. A construction and arrangement of the flange k and the hood of the
plunger which latter is subject to the pressure of a spiral spring, fully as
described and for the purpose set forth.