IMPROVEMENTS IN ANTI-MAGNETIC SHIELDS FOR WATCHES
Year: 1884

page_text: I, CHARLES KNAPP GILES, of the City of Chicago in the County of Cook, and
State of Illinois, United States of America, Jeweller do hereby declare the nature
of my Invention for "IMPROVEMENTS IN ANTI-MAGNETIC SHIELDS FOR WATCHES "
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 means for preventing watches from becoming
magnetized.
It is well known that when watches are brought near to powerful magnets
their utility is affected as the many parts of the movement become magnetized.
At the present time when powerful dynamo electric machines are in general
use for various purposes the liability to this injurious disturbance in watches is
greatly increased, for the magnets of these machines are frequently so powerful
that persons coming very near them will find the watches they carry affected as
described, by the magnets. It is a somewhat difficult and expensive operation to
demagnetize a watch thus affected, and until this is done the watch is practically
worthless.
It is also well known that the time-keeping qualities of a watch are very
materially and deleteriously affected by the so-called "electric" belts, pads, soles,
and other electric devices now so commonly worn. The persons and clothing of
individuals wearing these belts are so charged with magnetism that they find it is
impossible to wear a watch and have it keep accurate time, as it will with another
person not so affected with magnetism.
The object of this Invention is to overcome this difficulty and completely protect
the watch from the deleterious influence of magnets so that it may be carried into
the presence of dynamo machines or into the presence of magnets elsewhere with
perfect security against injury; and to shield the watch from the magnetism and
magnetic currents of the body.
This result I accomplish by surrounding the works of the watch with a complete
shield of highly magnetic metal, or an alloy or combination of metals, which, in
common language, may be said to absorb or turn aside the magnetic currents
thereby preventing their reaching the watch movement.
I will now proceed to describe in detail various modes in which I have carried
this Invention into practice.
In the accompanying Drawing
Figure 1 is a side elevation of the improved shield in the form of a box adapted
to receive and enclose a watch movement.
Figure 2 is a vertical section of the same on the line xx Figure 1.

page_text: Figure 3 is a back view of a watch case with the box shield applied thereto, the
dome at the back being open and a portion of the shield broken away.
Figure 4 is a vertical section of the same closed, on the line y y Figure 3.
Figures 5, 6 and 7 are vertical sections of cases and box shields showing
modifications in the construction and application of the Invention, and
Figure is a vertical section of a case in which my improvement is applied to
the case itself, the Figure showing the front and back plates partly thrown open.
Referring to Figures 1 to 4, A. indicates a box of size and form adapted to
receive a watch movement B and to be mounted in a dust proof box or any ordinary
case without increasing the size or bulk of the watch.
This box is made, preferably of a thin sheet of iron, which, as is well known is a
highly magnetic metal. Any other highly magnetic metal or compound may,
however, be used instead of iron. A thin sheet C of the same metal is fastened to
the top of the plate b of the watch movement. This sheet extends entirely over
the movement plate and projects beyond it all round so that the edge may turn
over and down to form a flange c, thus making a cover for the box A as shown in
Figure 2 of the Drawing. The relative diameters of the box and cover may be
such as to admit the box within the cover, or vice versa as may be desired, the
former arrangement being preferred, however. The dial D is placed above the
sheet of metal C, and fastened to the movement plate in the usual manner or the
same result or effect can be accomplished by enamelling the dial on a thin sheet of
iron instead of copper as usually done.
In applying this device the thin plate which makes the cover is attached to the
movement before the latter is mounted in the box and then the movement is placed
in the box the cover fitting over or into the latter, and the movement being
secured within the box in any suitable manner. It will be seen that the movement
will then be entirely encased by a thin sheet of iron or other highly magnetic
metal, and will present the appearance shown in Figure 1.
The box is constructed so that it is adapted. to be received and mounted in an
ordinary watch case. This casing operates as a perfect shield to the works within
whenever the watch is brought near to a magnet. It is not necessary to enter
upon a scientific statement of the reason but, using common words it may be said
that the shield of highly magnetic metal absorbs or turns aside the magnetic
influence proceeding. from the magnets, so that the watch-works within remain
unaffected. Electricians will readily understand that this must be so; and I have
found the effect to be as stated above, by practical experiments by holding a watch
enclosed in one of these shields close to a powerful dynamo-machine, and all round
it, without magnetizing the works in the least.
The box shield may be made practically dust proof though provided, when
necessary, with the usual small openings for winding, regulating etc. These small
openings I have found do not destroy the practical utility of the shield.
In Figures 3 and 4 I have shown the box-shield mounted in a case which, in
this instance, is an ordinary open face case E consisting of a centre e, a ring
bezel e hinged thereto and adapted to receive and hold the crystal F, and a back
plate or dome e also hinged to the centre. The watch movement and the shield
attached to and surrounding it are placed within the centre and fastened there in
the same way in which the movement is applied and fastened in the ordinary
construction without the shield, which will be understood without further
description.
I have thus described one way in which my Invention may be carried out
practically; but I do not limit my improvement to this particular mode of
embodiment. The shield may be of any suitable form and construction provided
only that it so nearly encloses the watch as to accomplish the object set forth above
and it may be made of any metal or compound which is adapted to secure the
result described. It will also be understood that my improvement is a device
applied permanently to the watch, being in fact a part of it and carried with it.-

page_text: I wish it also understood that I do not limit my Invention to its application to
any particular kind of case, as the device may be applied to various styles of cases.
In Figures 5, 6 and 7, I have shown some variations which may be made in the
case and shield. In Figure 5, the box or shield G is made so as also to form
the case to which an independent ring centre G¹ is applied. The front g is
constructed to receive and hold the crystal and the dome g' is secured to the front
directly by screw threads g³ and each portion is provided with flanges g³ projecting
beyond the central portion between which the ring centre is received and held
by turning down the dome upon the centre. If desired, the centre may be secured
to the box case for additional security. In this instance, the box which becomes
the case must be made of some material which will constitute a shield, as described
above, or an additional shield like that first described may be applied to the works
inside of the case. In the former construction it may be found necessary to apply
the thin plate mentioned above under the dial for the more complete protection of
the works within.
In Figure 6, there is a band or ring H of suitable shape and size to receive the
movement and provided at both edges with outside screw threads h. The front H¹
which holds the crystal is threaded so as to be turned on one edge of this band
and the back or dome H is also similarly threaded so as to be turned upon the
other edge thereof. Both front and dome are flanged so as to project somewhat
beyond the ring and so clamp and hold an independent centre I, which is applied
between them whenever the box is to be converted into a case. The box alone
may be used for keeping and transporting the movement. As an additional
protection, there may also be a back plate h' which is fastened to the central ring
or band by an internal screw thread h* in the latter. In this construction, the box
may be used the same as in that last described as shown in Figure 5, that is it
may be either itself the shield or may receive and hold the latter within it.
In Figure 7 the construction shown is similar to that last described, except that
the box, formed by the parts H, H³, H* and I is applied to the ordinary case,
either a hunting case or open faced. In the Drawing a hunting case J is shown
consisting of a centre f to which is hinged in the usual way a front plate ¹ and a
back plate, the centre being applied to the box in the same way as last described.
If an open face watch is desired in this construction, it is simply necessary to
modify the front plate, making it a simple ring to close down around the bezel; or
the crystal may be mounted in this ring as a bezel and then the front part H¹ is
made a plain ring. In this construction, I prefer always to make the box itself
the shield.
In Figure 8 I have shown the application of my Invention to that particular
kind of watch case generally known as a "filled" case. This particular kind of
case, as is well known, is composed of a central plate of baser material with a plate
of gold or silver on each side thereof. In the application of my improvement to
this kind of case, the middle or filling plate is made of such material as that above
described for the anti-magnetic shield as first set forth. In the Drawing, K indicates
a watch-case; in this instance of hunting style, and the several parts of the case
are made by the filling process just mentioned above, being composed of three
plates k, k¹ and the first and last of which are of gold or other precious metal,
while the middle plate ¹ is of some highly magnetic metal or metal alloy such as
already mentioned above. The watch movement is mounted, in this case, in the
usual way and it will be seen that it is then completely enclosed by an anti-
magnetic protector or shield formed by the case itself. As an additional protection
in this direction, the back cap L may also be filled in the same way, if desired.
It is obvious, too, that the case may be made wholly of some highly magnetic metal
or metal alloy which may then be plated with gold or silver. An anti-magnetic
shield will thus be obtained for the movement within.
These are some of the ways in which my Invention may be practically applied.
I have not attempted to show all modes of its application, and as heretofore stated,
do not limit my Invention to any particular construction of box or case or to any

page_text: particular manner of obtaining the shield, provided only that the construction and
arrangement of the parts is such that the watch movement is substantially enclosed
within a shield which prevents the deleterious effect of magnets and magnetic
currents.
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
First. A watch movement, in combination with a shield of highly magnetic
metal or material, wholly or in part surrounding and enclosing the movement
when mounted within the case, substantially as, and for the purposes, set forth.
Second. A watch movement, in combination with a box of highly magnetic
metal or material within which the movement is held, and a case centre within
which the box is mounted and held, whereby the movement is substantially
enclosed within an anti-magnetic shield when set up to complete the watch,
substantially as, and for the purposes, set forth.
Third. A watch movement, in combination with a box of highly magnetic metal
or other suitable material adapted to receive the movement, and a cover of like
material supported from the dial and extending over the plate of the movement,
substantially as, and for the purposes, set forth.
HASELTINE, LAKE & Co.,
For the Applicant.