Improvements in Watch Movement Bridges.
Year: 1899

page_text: Date of Application, 30th Oct., 1899-Accepted, 9th Dec., 1899
COMPLETE SPECIFICATION.
Improvements in Watch Movement Bridges.
I, JOSEPH LAWRENCE KURTZ, Watch and Chronometer Maker, of 14, Maiden
Lane, in the City of New York, Borough of Manhattan and State of New York,
U.S.A., 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 bridges for watch-movements, and more especially
to an improved bridge for watch-balances and escapements; and the invention
consists of a bridge for watch-movements, in which the rear end of the bridge is
attached by a screw post to the bottom plate of the movement, and supported
on three regulating screws arranged near the fastening screw post, each regulating
screw being formed of two sections, a shorter section passing through the bottom
plate of the watch movement, and a longer section passing through the rear end
of the bridge, said sections abutting near the base of the bridge so as to permit
the accurate adjustment of the front end of the bridge to the staff of the balance-
wheel, and the expansion and contraction of the attaching screw-post and regu-
lating uniformly with the staff, so as to prevent a binding action of the bridge
on the staff as will be fully described hereinafter and finally pointed out in the
claims.
In the accompanying drawings.
Fig. 1 is a top-view of a watch-movement with my improved bridge applied
thereto, and
Fig. 2 is a vertical longitudinal section through the bridge, on line 2-2,
Fig. 1, drawn on a larger scale.
Similar letters of reference indicate corresponding parts.
Referring to the drawings, A represents a balance wheel, B the bridge of the
same, and C is the bottom plate of the movement. The staff D of the balance
wheel A is centered in the usual manner in suitable jewels jj of the bottom
plate and bridge respectively, and the bridge B, instead of being made with a
shouldered rear end, is preferably made with a solid or "full" rear end, as shown
in Fig. 2. This shape is made for the purpose of arranging a number of regu-
lating screws dd by means of which the accurate adjustment of the bridge B to
the staff D of the balance-wheel can be obtained. The rear end of the bridge B
is attached to the bottom plate C by a fastening screw e and adjusted preferably
by means of three regulating-screws dd which are arranged near the fastening
Screw c. The rearmost regulating-screw d is located in line with the fastening
screw e and the staff D) of the balance, while two additional regulating-screws d
are preferably located in front of the fastening-screw e, one at each side thereof,
as shown clearly in plan view in Fig. 1.
The regulating screws dd are each formed of two sections namely of a longer
section which passes through the rear end of the bridge B; and of a shorter
section or stud that passes through the bottom plate C. The sections

page_text: and abut one against the other by means of flat faces formed at their adjacent
ends, as shown in Fig. 2, so that the regulating screws d can be readily adjusted
to the staff after the fastening screw is placed in position in the rear end of the
bridge. By adjusting the regulating screws dd, the bridge can be set in the
most accurate manner to the staff D of the balance wheel. As the bottom of the
rear end of the bridge B does not form contact with the bottom plate C, it can
expand or contract independently of the regulating screws, which latter, being
preferably of steel like the staff, expand or contract uniformly with the latter,
and keep up the proper distance between the jewels of the staff, so that the so-
called end-shake" of the staff is equalised in all temperatures. When the
screws are once properly adjusted, the bridge will always retain its proper position
towards the staff, owing to the independent expansion of the staff, fastening screw,
and regulating screws. My improvement is also adapted for the escapement-
bridges of watches.
"
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what
I claim is:
-
1. The combination, with the bridge of a watch-movement and its staff, of a
fastening-screw for attaching the rear end of the bridge to the bottom plate of the
movement, and regulating-screws arranged adjacent to said fastening-screw and
formed of two sections each, one section being attached to the bottom plate and
the other to the rear end of the bridge so as to retain the bridge in accurate
position relatively to the staff in all températures substantially as set forth.
2. The combination, with the bridge of a watch-movement and its staff, of a
fastening-screw for attaching the rear end of the bridge to the bottom plate of the
movement, and regulating-screws arranged in proximity to said fastening-screw,
said regulating-screws being formed each of two sections, a shorter section
located in the bottom plate of the movement and a large section located in the
rear end of the bridge, said sections abutting against each other below the
bottom of the rear end of the bridge, substantially as set forth.
Datad this 10th lore of October 1800
TONGUE & BIRKBECK,
31, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.