Improved Electrical Push-button for Signalling Circuits.
Year: 1890

page_text: Date of Application, 3rd Nov., 1890
Complete Specification Left, 21st July, 1891-Accepted, 22nd Aug., 1891
PROVISIONAL SPECIFICATION.
[Communicated from abroad by HEINRICH MESSING, of Offenbach a/Main,
Germany.]
Improved Electrical Push-button for Signalling Circuits.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Patent Agent, do hereby declare
the nature of this invention to be as follows:
This invention relates to an improved construction of electrical push-button for
signalling circuits, wherein the cap carrying the push is secured to the base carrying
the contact pieces in a readily attachable and detachable manner.
For this purpose the base has a cylindrical projection, round the periphery of
which is formed a groove of semicircular section into which is sprung a caoutchouc
ring. The cap carrying the push-button is hollowed so as to fit easily over the
cylindrical projection but has an inward projecting rim at its end, the internal
diameter of which is slightly less than the external diameter of the caoutchouc ring,
so that on pushing the cap over the said projection, its rim will be sprung past the
caoutchouc ring and this will consequently hold the cap in position, while it can be
readily removed by pulling it back over the caoutchouc ring again.
Dated this 3rd day of November 1890.
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improved Electrical Push-button for Signalling Circuits.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Patent Agent, 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:
This invention relates to a construction of electrical push button for signalling
circuits; having the cap which carries the push secured to the base which carries
the contacts in such a manner that it can be readily removed from the base or put
on it, as shewn by the accompanying drawing which is a vertical section.
The base A has a cylindrical part B projecting upwards, in the periphery of
which is formed a groove of semicircular section into which is sprung a caoutchouc
ring C. The cap D has at its lower edge an inwardly projecting lip E having its
internal diameter somewhat less than the external diameter of the caoutchouc ring C.
On pushing the cap D down on the base, the lip E compresses the caoutchouc ring
inwards, and, when it has passed, the ring springs out again so as to overlap the
lip E. Thus the cap is held in position with sufficient firmness to resist ordinary
accidental disturbance, but so that it can be pulled off when desired.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
An electrical push button having its cap held in position by a caoutchouc ring

page_text: occupying a groove of the base and overlapping an inwardly projecting lip of the
cap, substantially as described.
Dated this 21st day of Túl. 1901
ABEL & IMRAY,
Agents for the Applicant.