IMPROVEMENTS IN WATCH CASES AND IN Southampton Buildings, London. SPRING FASTENING AND OPENING DEVICES THEREFOR.
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by William Robert Lake at the Office
of the Commissioners of Patents on the 25th September 1880. A communi-
cation from abroad by Georg Friedrich Mertz, of Mitau, Russia.
WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
IMPROVEMENTS IN WATCH CASES AND IN
Southampton Buildings, London.
SPRING FASTENING AND OPENING DEVICES THEREFOR.' [A communication from
abroad by Georg Friedrich Mertz, of Mitau, Russia.]
39
This Invention relates to improvements in watch cases, and to the springs which
serve for opening and fastening the same, and it has for its object to prevent the
entrance of dust which takes place through the openings in which work the
spring-fastenings of ordinary watch case lids and the spring which causes such lids
to fly open.
My improvements differ from the systems hitherto applied principally in the
fact that I do not place the fastening spring of the watch-lid into the interior
of the watch case which contains the works, but arrange such springs on the
outside thereof, whilst of the springs which cause the lid to fly open one is also
arranged on the outside, whilst the other works through an aperture, which when
the lid is open is perfectly closed by the action of the spring itself, whereby it is
possible to close these cases quite hermetically without leaving any passage
through which dust could penetrato into the watch work.
In the constructions hitherto known this has not been possible, as the springs
aforesaid act outward from the interior of the case, and a certain amount of space
has to be left in the interior for the play of such springs, and dust is liable to get
into this space through openings provided for the heads of the springs to pass
outward; the working of the watch therefore becomes impaired.
In carrying the said Invention into practice I construct and arrange the various
springs of a watch case in the following manner, that is to say:-
Close by the bow or pendant of the watch I place the fastening spring, which I
fix on the outside of the case containing the works, but so arranged that it is
covered by the lid or outer cover when the latter is closed, and this spring has a
hook-shaped head, which is slightly bent so as to economize space as much as
.
11

page_text: possible by making the said spring capable of adapting itself (when pressed
back by the lid being shut) to the form of the recessed ring which serves to
hold the glass; in this ring I provide a small recess or space allowing the spring
to recede.
The pusher is mounted in the bow or pendant in the usual manner. The said
pusher carries on one side a small steel-pin, which when the pusher is depressed
presses against the aforesaid spring and throws the same out of engagement with
the lid or cover, and the latter is released. The fastening spring is fixed outside
the casing containing the works or movement and in line with the centre of the
watch, so that there is no need for an opening in the watch case, but it is covered
by the lid when the same is shut as stated.
The spring for causing the lid or cover to fly open when the fastening spring
releases the same I construct and arrange as follows, that is to say :-
For the purpose of obtaining sufficient resistance or elasticity in the very limited
space between the lid or cover and the case containing the works I use two springs,
which springs are caused to act against each other; one is a flat and the other a
coiled spring. The fat spring is attached by screws to the lid or cover, and its
end, which is hook-shaped, presses upon a pin projecting from the interior of the
case and exactly guided in a hole therein. To prevent the end of the aforesaid
spring slipping off the pin, the front end of the former has a slight indentation
which engages with the slightly rounded end of the pin. This pin is made in one
piece with a small disc or plate which forms its base, and is surrounded by one end
of a coiled spring; the other end of the said coiled spring bears upon a second disc
or plate fixed to the other side of the case by a stud or by other suitable means.
The coiled spring has the tendency to press the pin, with which it is connected by
the disc at its base as aforesaid, outward. The said spring, as well as the flat spring,
is compressed when the lid is shut, and by thus arranging the two springs to press
against each other their effect is increased, so that when the fastening spring is com-
pressed they will cause the lid to fly open with great ease.
As herein before mentioned, the pin is exactly guided in a hole in the case, which
hole is furthermore completely closed by the disc upon the lower end of said
pin, as by the coiled spring this disc is firmly pressed against the edge when the
lid is open; it is therefore impossible for the dust to penetrate.
By reason of these two springs acting against each other both are only half
compressed, which causes the same to last a longer time than would otherwise be
the case.
The chief advantage offered by the constructions above set forth is, as
has been herein before stated, that it is thereby rendered possible entirely to prevent
the entrance of dust into the interior of the watch. It is obvious that this arrange-
ment of the springs may be used for any watch, as slight differences in the shape
of the case do not affect the peculiarity of construction.