Improved Means of Fixing Glasses and Bezels in the Cases or Covers of Clocks, Measuring Instruments, and other Apparatus.
Year: 1895

page_text: Date of Application, 2nd Sept., 1895
Complete Specification Left, 1st June, 1896-Accepted, 4th July, 1896
PROVISIONAL SPECIFICATION.
Improved Means of Fixing Glasses and Bezels in the Cases or Covers
of Clocks, Measuring Instruments, and other Apparatus.
I, SYDNEY EVERSHED of Woodfield Works Harrow Road in the County of
London, Electrical Engineer do hereby declare the nature of this invention to be
as follows:-
--
In fixing the circular glass fronts into clock cases and the like, difficulties are
frequently experienced in providing for the irregular thickness of the sheet or
plate glasses usually employed. The object of my invention is to provide an
elastic support for the glass so that a glass of irregular thickness and glasses
differing in thickness amongst themselves may be easily and firmly fixed within
the case of an instrument without any. adjustment or alteration in the clamping
devices.
According to my invention the circular cover or case of an instrument may have
a groove of semi-circular section cast or spun round near the top of the case just
below the level of the glass front and concave to the inside of the case.
The top
edge of the case is bent over inwards to form a lip against which the glass can be
pressed from below. The glass having been put in place against the lip, a split
ring, of suitably elastic metal and of a diameter equal to the internal diameter of
the case, is pushed up into the case until it snaps into the aforementioned groove
by expanding to a larger diameter. The ring herein called the clamping-ring.--
must be made of a circular section having a radius nearly equal to that of the
semi-circular groove in the case. When thus snapped into place the clamping-ring
presses tightly, but with an elastic pressure against the under surface of the glass
and holds it firmly up against the internal lip. The clamping-ring may be bent
up out of a metal wire of circular section but I prefer to use a ring of hollow
section split throughout its whole length. Such a ring is readily made by drawing
a metal strip into a nearly closed tube leaving a little space between the edges
of the strip. The tube being bent into a circular shape forms a clamping-ring
which, being elastic both as regards its principal diameter and its section, adapts
itself very perfectly to its position under the glass and in the groove so that a glass
of irregular thickness is firmly held without shake. Moreover the use of the
hollow flexible clamping-ring allows the thickness of the glass used to be varied
within comparatively wide limits without any risk of either a loose fit or a broken
glass.
When in addition to the glass a bezel ring is to be employed to give a finished
appearance to the face of the instrument the clamping-ring serves to hold both
glass and bezel ring, the latter being made with a small external flange which
when in place is caught and firmly held between the clamping-ring and the under
surface of the glass.
My invention is applicable to the cases or covers of clocks, aneroid barometers,
tachometers, steam gauges, ammeters, voltmeters, electric and other meters and in
general wherever a circular glass plate, front or cover has to be fixed to the case
or cover of any apparatus.
Dated this 30th day of August. 1895

page_text: Improved Means of Fixing Glasses and Bezels in the Cases or Covers
of Clocks, Measuring Instruments, and other Apparatus.
I, SYDNEY EVERSHED, of Woodfield Works Harrow Road in the County of
London, Electrical Engineer, 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:-
In fixing the glass fronts into clock cases and the like, difficulties are frequently
experienced in providing for the irregular thickness of the sheet or plate glasses
usually employed. The object of my invention is to provide an elastic support for
the glass so that a glass of irregular thickness and glasses differing in thickness
amongst themselves may be easily and firmly fixed within the case of an instrument
without any adjustment or alteration in the clamping devices.
the case.
According to my invention the cover or case of an instrument has a groove of
semi-circular section formed near the top of the case just below the level of the
glass front and concave to the inside of the case. The top edge of the case is bent
over inwards to form a lip against which the glass can be pressed from below.
The glass having been put in place against the lip a divided ring herein called the
clamping ring, of suitably elastic metal and of a diameter equal to the internal
diameter of the case, is pushed up into the case until it snaps into the afore-
mentioned groove by expanding to a larger diameter. The clamping ring is of a
circular section having a radius nearly equal to that of the semi-circular groove in
When thus snapped into place the clamping ring presses tightly but
with an elastic pressure against the under surface of the glass and holds it firmly
up against the internal lip. Almost any elastic material may be used for the
clamping ring but I prefer to use a hollow metal ring not only divided at one place
on its perimeter to enable it to spring outwards into the groove, but also split along
the perimeter so as to give it an elastic section. Such a ring is readily made by
drawing a metal strip into a nearly closed tube leaving a little space between the
edges of the strip. The tube being bent into a circular or other shape forms a
clamping ring which being elastic both as regards its principal diameter and its
section, adapts itself very perfectly to its position under the glass and in the
groove so that a glass of irregular thickness is firmly held without shake.
Moreover the use of the hollow flexible clamping ring allows the thickness of the
glass used to be varied within comparatively wide limits without any risk of either
a loose fit or a broken glass.
c
When in addition to the glass a bezel ring is to be employed to give a finished
appearance to the face of the instrument the clamping ring serves to hold both
glass and bezel ring, the latter being made with a small external flange which
when in place is caught and firmly held between the clamping ring and the under
surface of the glass.
The drawings accompanying this specification illustrate the application of my
invention to a metal case such as is commonly employed as the cover of an
electrical measuring instrument.
In Fig. 1 the top part of the case C. is shown in section and has a semi-circular
groove A. formed near its upper edge, the edge itself being turned over so as to
form the lip L. The glass plate G. is pressed against the lip by means of the
clamping ring R.
Fig. 2 in which similar letters refer to similar parts shows the manner in which
a bezel ring B. is clamped between the glass and the clamping ring R.
In the drawings the clamping ring where seen in section is shaded black for the
sake of clearness; the other parts where seen in section are shaded with section

page_text: lines in the ordinary manner. It will be noticed that the slit in the hollow
clamping ring is shown on its inside diameter; this, although the best position for
the slit, is not essential to my invention. Clamping rings in which the slit is on
the outside diameter may be used, and as already stated the clamping ring may be
made of almost any elastic material so long as it has sufficient elasticity outwards
to spring tightly in the groove A, and in addition a certain amount of elasticity
is desirable in its section so that it may adapt itself to glasses of varying
thickness.
.
In my Provisional Specification I have described this invention as though it
were only applicable to circular cases. It may however be employed whenever
the case is of such a shape as will allow of a groove being turned, spun, or rolled
within it. For example:-In an oval case the necessary groove may readily be
formed by rolling with the tools in common use, it being understood that the
clamping ring, glass and bezel are of the same shape as the case.
My invention is applicable to the cases or covers of clocks, aneroid barometers,
tachometers, steam gauges, ammeters, voltmeters, electric and other meters, and in
general wherever a glass plate, front or cover has to be fixed to the case or cover
of any apparatus.
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) Means for fixing glasses and bezels into cases or covers comprising an
internal groove and lip within the cover and a divided elastic clamping ring
adapted to fit within the groove and hold the glass against the lip substantially as
described.
(2) Means for fixing glasses and bezels into cases or covers substantially as
described with reference to Figs. 1 & 2.
Dated this 1st day of June 1896.