An Improved Cover for Electric Push Knobs and the like.
Year: 1892

page_text: Date of Application, 4th June, 1892
Complete Specification Left, 2nd Mar., 1893-Accepted, 2nd June, 1893
PROVISIONAL SPECIFICATION.
An Improved Cover for Electric Push Knobs and the like.
I, ALEXANDER SHIELS of 190 Bath Street Glasgow, M.B., C.M., B.Sc. do
hereby declare the nature of this invention to be as follows:-
-
This invention relates to a detector cover for electric push knobs and the like
and it has for its object to enable the top of the cover to be easily taken off and
the glass or mica window to be easily replaced or changed.
At present, when it is desired to replace the glass window the whole cover has
to be unscrewed and taken off. With my invention this is avoided.
The improved detector cover is made in two parts, the base part being made
with a bayonet joint or joints and with a spring catch or stop. The top part, in
which the window may be secured, has suitable projections which fit into the joint
or joints of the base part. The projections, or only one of them, may have a flat
side to catch against the spring stop.
The parts of the cover are taken asunder by first pressing down the spring stop
and then twisting or turning the projections out of the bayonet grooves. The
parts are fitted together by merely pressing down the top and then giving it a turn.
Instead of having bayonet joints other equivalent joints may be used.
Dated this 3rd June 1892.
H. D. FITZPATRICK,
Glasgow and London, Agent.
COMPLETE SPECIFICATION.
An Improved Cover for Electric Push Knobs and the like.
I, ALEXANDER SHIELS, of 190 Bath Street, Glasgow, M.B., C.M., B.Sc., 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 detector cover for electric push knobs and the like
and it has for its object to enable the top of the cover to be easily taken off and
the glass or mica window to be easily replaced or changed.
At present, when it is desired to replace the glass window the whole cover has
to be unscrewed and taken off. With my invention this is avoided.
The improved detector cover is made in two parts, the base part being made
with a bayonet joint or joints and with a spring catch or stop. The top part, in
which the window may be secured, has suitable projections which fit into the joint
or joints of the base part. The projections, or only one of them, may have a flat
side to catch against the spring stop.
The parts of the cover are taken asunder by first pressing down the spring stop
and then twisting or turning the projections out of the bayonet grooves. The
parts are fitted together by merely pressing down the top and then giving it a turn.
Instead of having bayonet joints other equivalent joints may be used.
And in order that my said invention may be properly understood, I have hereunto
appended an explanatory sheet of drawings, whereon :-
Fig. 1 is a plan view of the detector cover.
Fig. 2 is a view, looking at the cover from below.
Fig. 3 is
cross section, on the line -x, Fig. 1.
Fig. 4 is a cross section, on the line y-y, Fig. 1, and looking in the opposite
isation to bio 2

page_text: Fig. 5 is a view of the upper part of the cover, looking from below.
Fig. 6 is a view of the base part.looking from below.
Fig. 7 is an enlarged detail view.
Referring to the drawings, whereon the same reference letters, wherever repeated,
indicate similar parts:-
a is the base part; b the cover and c the glass or mica window.
As will be seen the base a which has two bayonet slots d, d', is also provided
with a spring catch or stop e. This stop e may consist, as shown at Fig. 7, of a
flat spring el at the end of which is a small block e. The spring e' is pinned to a
lug on the base a. The cover has two projections f, g, one at each side, as
shown at Fig. 5. The projection may be flat at one side.
To fit the cover in place all that is necessary is to insert the projection or pin/
in the slot and the pin g in the slot d, then press the cover down firmly and turn
it round slightly until the pins move into, and are prevented from vertical move-
ment by, the horizontal parts of the bayonet slots. When the cover is secured in
place the block of the spring e bears against the flat side of the pin f and locks
the pin and cover in position. If it is desired to take off the cover, the window
must first be broken and then the spring pressed down sufficiently to permit the
pin to override the block when the cover is turned. When the spring is so
pressed down the cover can be turned, until the pins clear the horizontal parts of
the slots d, d, when it can be easily taken off.
It is obvious that joints of a similar character to bayonet joints may be used in
lieu thereof.
My invention is applicable for use with press buttons, push knobs, and like
similar devices.
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 cover for electric push knobs and the like, made substantially as herein-
before described with reference to the drawings annexed.
Dated this 1st day of March 1893.
H. D. FITZPATRICK,
Glasgow and London, Agent.