AN IMPROVED CHRONOGRAPH
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at the
Office of the Commissioners of Patents on the 12th September 1882. Com-
municated to him from abroad by Pierre Raphaël Moreau of Geneva,
Switzerland.
"
ALEXANDER MELVILLE CLARK of the firm of A. M. and W. Clark of 53 Chancery
Lane in the County of Middlesex, Patent Agents, "AN IMPROVED CHRONOGRAPH."
[Communicated to him from abroad by Pierre Raphaël Moreau of Geneva,
Switzerland.]
This Invention relates to an improvement in chronographs and consists more
particularly in the arrangement of the bent lever which is the principal part of the
mechanism, and which fulfils a double purpose as hereafter described. The
arrangement of this part of the mechanism permits of the construction of charm
chronographs, but is applicable to chronographs of all dimensions.
In order that the Invention may be more readily understood, I have illustrated
an example of the improved chronograph in the annexed drawings in which
Figure 1 represents a view of the chronograph mechanism beneath the dial, and
also of the dial itself with the hands stationary at zero. Figure 2 shows similar
views, the hands being set going by the turning down of the pendant bow.
Figure 3 shows similar views, the hands being stopped after going a certain
time. The same letters of reference indicate the same parts in all these figures.
The bent lever b and its combination with the stop piece c, constitute the
essential part of the Invention. The bent lever b lies immediately beneath the
dial and is pivoted at o to the plate g. It is furnished at h with a stud moving in
a slot in the plate g which acts on the stop piece c pivoted at the other side of the
plate g. This lever c has a horn q against which the stud h abuts to return the
lever c to its former position after being pressed inwards by the push piece k.
This stud carries a spring r which is caused to come in the path of the balance
wheel of a watch movement (not shown) and arrest it when it is deflected by being
caused to ride up on a bevelled projection p on the stop lever c. The bent lever b
is moved away from the heart wheels and held in that position as shown in
Figures 2 and 3 by pressing inwards the push piece d within the pendant, this
push piece being thus moved by means of an eccentric screw which traverses it as

page_text: well as the pendant bow, so that by folding down the bow, the bent lever b is
moved in the direction of the arrow, figure 1, and in raising the bow, it is moved
in the opposite direction by a spring and so returned to its normal position.
The operation of timing a performance by means of the chronograph is as
follows The chronograph being at zero as in Figure 1, it is set in motion by
turning down the bow thereby pressing in the push piece d and withdrawing the
bent lever 6 from the heart wheels (which are fixed on the arbors of the minute
and second hands respectively) and the spring r at same time slipping off the
bevelled part p of the stop lever c, the balance wheel is free to vibrate and the
chronograph set going as shown in Figure 2. When it is desired to stop the hands
the lever c is pressed inwards by its push piece k and coming again beneath the
spring as in Figure 3, causes it to arrest the balance wheel.
C
b
Finally by turning up the pendant, the parts b and c are returned to their first
or normal positions, and the part 6 pressing against the heart wheels, causes the
hands to fly back to zero as in Figure 1.