Improvements in and connected with Electric Bells.
Year: 1892

page_text: Date of Application, 20th Apr., 1892
Complete Specification Left, 18th Jan., 1893-Accepted, 1st Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in and connected with Electric Bells.
HERMANN OPPENHEIMER 34 Aldermanbury London E.C. Manager to the
International Electric Company sole depot of Mix & Genest Limited, do hereby
declare the nature of this invention to be as follows:-
The most important mechanical part in an electric trembling bell is the
armature A with the hammer stem S and the contact spring arrangement as shewn
in Figure 2 of the accompanying drawing.
On completing a circuit the electro-magnet attracts the armature and the current
is automatically interrupted by the contact spring which with its bottom part
causes the armature to recoil, an operation which is repeated as often as the circuit
is completed. This attracting and repelling of the armature causes the hammer to
strike against the gong producing the ringing. In order to effect a full and
effective sound it is essential that the hammer should have a stroke as abrupt as
possible so that it should not touch the gong when the armature is attracted but
the stem must be of such springy structure so as to bring up the hammer against
the gong.
Generally the stem S of the hammer is screwed into the armature A, but the
rapid vibrations causing the hammer to strike are conducive to loosening the
connection between hammer and armature. Even stems which have been fixed by
means of pressing them into the armature readily loosen and this drawback I am
avoiding and remedying by the following method.
I punch from an iron sheet a piece in the form of the armature and being on its
extension of a smaller shape. This latter portion of the stamping 1 am drilling and
after this has been done I am using a draw claw bringing the thinner part between
this twofold cutter and thus attaining the result of giving the stem the necessary
flexibility.
In mines, damp places, or where exposed to the open air ordinary bells mounted
on wood soon get out of order in consequence of the change of moisture in the
atmosphere. For the aforesaid purpose I have constructed a bell as shewn in
Fig. 3 which is pre-eminently qualified to resist all climatic influences both through
the material I use and the construction of the essential parts.
The cast iron bell board on which I mount the bell has a small projecting
square rim R round which I lay a cord C or other similar material of suitable
thickness soaked in paraffin or tallow (Fig. 3). The cover also made of cast iron
has a groove or recess F on its bottom part in which the cord fits Fig. 4. By
screwing down the cover I press the groove F so tightly against the cord C and
the projecting rim so that the movement and terminals which latter I also mount
under cover contrary to the customary manner (allowing an aperture to fix the
wires to same) are absolutely impermeable & waterproof.
Dated the 5th day of April 1892.
COMPLETE SPECIFICATION.
Improvements in and connected with Electric Bells.
I HERMANN (Oppenheimer, 34 Aldermanbury, London E.C. Manager to the
International Electric Co. do hereby declare the nature of this invention and in
5 what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The most important mechanical part in an electric trembling bell is the armature A

page_text: with the hammer stem S and the contact spring arrangement as shewn in Figure 2
of the drawing filed with Provisional Specification.
On completing a circuit the electro magnet attracts the armature and the current
is automatically interrupted by the contact spring which with its bottom part
causes the armature to recoil, an operation which is repeated as often as the circuit
is completed.
This attracting and repelling of the armature causes the hammer to strike
against the gong producing the ringing.
In order to effect a full and effective sound it is essential that the hammer
should have a stroke as abrupt as possible so that it should not touch the gong when
the armature is attracted but the stem must be of such springy structure so as to
bring up the hammer against the gong.
Generally the stem S of the hammer is screwed into the armature A, but the
rapid vibrations causing the hammer to strike are conducive to loosening the
connections between hammer and armature.
Even stems which have been fixed by means of pressing them into the armature
readily loosen and this drawback I am avoiding and remedying by the following
method :
I punch from an iron sheet a piece in the form of the armature (Fig. 2) and with
an extension S of a smaller size. This latter portion of the stamping I turn and
after this has been done I use a draw-plate similar in construction to those used by
wire-drawers, bringing the thinner part between this twofold cutter and thus
attaining the result of giving the stem the necessary flexibility..
In mines, damp places, or where exposed to the open air ordinary bells mounted
on wood soon get out of order in consequence of the change of moisture in the
atmosphere.
For the aforesaid purpose I have constructed a bell as shewn in Fig. 3 of
drawing, which is pre-eminently qualified to resist all climatic influences both
through the material I use and the construction of the essential parts.
The cast iron bell board on which I mount the bell has a small projecting
square rim R round which I lay a cord C or other similar material of suitable
thickness soaked in paraffin or tallow (Fig. 3.). The cover also made of cast iron
has a groove or recess F on its bottom part in which the cord fits. (Fig. 4.) By
screwing down the cover I press the groove F so tightly againt the cord C and the
projecting rim so that the movement and terminals which latter I also mount under
cover contrary to the customary manner, (allowing an aperture to fix the wires to
same) are absolutely impermeable and waterproof.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :
1. The manufacture and use of armature and hammer stem for electric bells in
one piece, substantially as described and in the manner set forth.
2. The manufacture and use of a watertight cover on iron bells, substantially as
described and for the purpose set forth.
Dated this 17th day of January 1893.
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