Improvements in Electric Bells.
Year: 1892

page_text: Date of Application, 18th May, 1892
Complete Specification Left, 13th Feb., 1893-Accepted, 29th Apr., 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by RICHARD VARLEY, of Passaic, New Jersey,
Electrician.]
Improvements in Electric Bells.
WOODHOUSE AND RAWSON UNITED LIMITED of 88 Queen Victoria Street,
London, E.C. in the County of Middlesex, Electrical Engineers, do hereby declare
the nature of this invention to be as follows:-
Our invention relates more especially to an improved method for locking the
adjustable contact screw and protecting the point of "make and break"
ordinary electric trembling bell.
in an
In carrying out the first part of our invention, we make use of a bush of india-
rubber or other similar material suitably mounted on the framework of the bell,
through which the contact screw passes, the elasticity of the material used grips
the screw, and takes up the vibration when the armature is in motion, thus
obviating any chance of the screw changing the position to which it has been
adjusted to obtain the best results.
In carrying out the second part of our invention, over that part of the contact
spring, which comes in contact with the contact screw, we stretch a thin mem-
brane of india-rubber sheet or other suitable elastic material, which will fit tightly
round the spring excluding dust and damp, in that portion of the rubber which is
opposite the point of the contact screw, we make a small hole through which a
portion of the screw passes, the screw having a suitable slot on its circumference
into which the rubber contracts, and forms a dust and damp-proof joint, the rubber
is sufficiently thin so as not to retard the make and break action.
To obtain the necessary means for connecting the conductor to the screw, we
may make use of a suitably shaped metal washer, which passes over the screw or
it may be tapped if preferable, having points bent over for forcing into the rubber
and a lug to which the conductor may be attached by any suitable means.
Dated this 18th day of May 1892.
WOODHOUSE & RAWSON UNITED, LIMITED,
A. L. Foley, Secretary.
COMPLETE SPECIFICATION.
Improvements in Electric Bells.
We, WOODHOUSE AND RAWSON UNITED LIMITED of 88 Queen Victoria
Street, London, E.C. in the County of Middlesex, Electrical Engineers, do hereby
declare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:—
Our invention relates more especially to an improved method for locking the
adjustable contact screw and protecting the point of make and break in an ordinary
electric trembling bell.
Referring to the accompanying drawings in which like letters refer to like parts.
Fig. is an electric bell showing the method of mounting the contact screw.
A is a bush made of india rubber or other suitable material, B is the adjustable
contact screw, C is a nut or washer having specially shaped lugs or tangs for
forcing into the rubber. A and C are shown in detail in Fig. 2. A has a recess D
Fig. 2 on its circumference and is forced into a hole in the framework of the bell,
[Price 8d1

page_text: and firmly gripped by the expansion of the rubber, which however is still further
increased by the passage of the screw B through its centre, which in its turn is also
very tightly gripped and prevented from moving. To the washer C is fastened
one end of the coils of the electro magnets, the other end being fastened to the
terminal E which is insulated from the framework of the bell, the washer C ruakes
electrical connection with the adjustable contact screw B and allows the current to
pass through the point of make and break to the framework of the bell and thus to
the terminal F..
In carrying out the second portion of our invention we stretch a thin membrane
of india rubber sheet or other suitable elastic material G Fig. 3 over that portion
of the spring H which comes in contact with the contact screw B, in order to
exclude dust and damp, in that portion of the rubber which is opposite the point
of the contact screw we make a small hole J, through which a portion of the
Ecrew B passes, the screw having a suitable slot K Fig. 3 on its circumference into
which the rubber contracts and forms a dust and damp proof joint, the rubber is
sufficiently thin so as not to retard the make and break action.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is :-
1. The contact screw of an electric bell fixed in an elastic bushing, and locked
there by the elastic pressure of the bushing.
2. The contact screw of an electric bell fixed in an elastic bushing and a nut
engaging with the screw, said nut being held from turning relatively to the
bushing.
3. In an electric bell a membrane of india rubber or other suitable elastic
material fitting closely round the contact spring, having a hole through which the
contact screw passes for the purpose of excluding foreign material from the point
of contact.
Dated this 11th day of February 1893.
WOODHOUSE & RAWSON UNITED, LIMITED,
A. L. Foley, Secretary.