IMPROVEMENTS IN WATCHES, CLOCKS, AND CHRONOMETERS
Year: 1876

page_text: LETTERS PATENT to Giuseppe Zaffira, of Pentonville Road, in the County of
Middlesex, Engineer, for the Invention of "IMPROVEMENTS IN WATCHES,
CLOCKS, AND CHRONOMETERS."
aled the 1st August 1876, and dated the 9th February 1876.
PROVISIONAL SPECIFICATION left by the said Giuseppe Zaffira at the Office
of the Commissioners of Patents on the 9th February 1876.
GIUSEPPE ZAFFIRA, of Pentonville Road, in the County of Middlesex, Engineer.
"IMPROVEMENTS IN WATCHES, CLOCKS, AND CHRONOMETERS."
This Invention has for its object the cheapening and simplifying the construction
of watches, spring clocks, and chronometers by dispensing entirely with the fusee
mechanism, and substituting therefor a more simple and effective arrangement..
This arrangement consists of a spiral groove or spiral projection formed in or ou
either end of the barrel containing the spring. Upon the square part of the axis of
the spring there is fitted so as to turn therewith.on winding a cross arm, and
underneath this arm and at right angles thereto there is fitted a slide, which is
slotted to fit the square end of the axis, and free to traverse across the same. A
small roller is carried in one end of this slide, which roller works in the spiral groove
or upon the spiral projection in the end of the barrel. Two springs are attached to
the cross arm, their inner or contiguous ends bearing against the opposite end of
the slide to that which carries the roller, and tend to keep the said roller pressed
with a certain amount of friction against the side of the spiral groove or projection.
When the spring is wound up the roller will be in the outer portion of the spiral,
and will gradually approach the centre of the barrel as it rotates. The convolutions
of the spiral should be so formed that the roller will at the commencement of the
rotation of the barrel exert a greater friction thereon, which friction should gradually
diminish as the strength of the spring decreases. This may be accomplished by
gradually increasing the depth of the groove, or decreasing the height of the pro-
jecting spiral rib or rail as it approaches the centre of the barrel.
The usual arrangements hitherto employed for preventing overwinding are also
dispensed with, as the roller and the spiral groove or projection answer the saine
purpose, without the inconveniences of the former arrangements.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Giuseppe Zafira in the Great Seal Patent Office on the 9th August
1876.
GIUSEPPE ZAFFIRA, of Pentonville Road, in the County of Middlesex, Engineer.
"IMPROVEMENTS IN WATCHES, CLOCKS, AND CHRONOMETERS."
'
My said Invention has for its object the cheapening and simplifying the con-
struction of watches, chronometers, and spring clocks by dispensing with the fusee
mechanism, and substituting therefor a more simple and efficient compensating
arrangement applied directly to the "going barrel" itself.
And in order that my said Invention may be fully understood I shall now
proceed more particularly to describe the same, and for that purpose shall refer to
the Figures on the annexed Sheet of Drawings, the same letters of reference indi-
cating corresponding parts in all the Figures.
Figure 1 of my Drawings represents an enlarged plan view of my peculiar com-
pensating arrangement applied to the going barrel of a watch, and showing the
centre wheel and the centre wheel pinion. In this Figure the mainspring is supposed
to be fully wound up; Figure 2 is a corresponding side elevation of the same; and
Figure 3 is a view similar to Figure 1, but showing the position of the parts when
the mainspring has run down. The rest of the Figures are enlarged details of parts
of my arrangement, which will be herein-after fully described and referred to.
a is the "going barrel"; b, the centre wheel, and c the centre wheel pinion; d is
a spiral groove or spiral projection, which according to my Invention I form in or
upon the end of the "going barrel" a, as shown clearly in Figures 1 and 3. Upon
the square end e of the barrel arbour there is fitted so as to turn therewith when
winding up the mainspring a cross arm (shown in plau and side elevation detached
at Figures 4 and 5), and beneath this arm and at right angles thereto there is
fitted a slide g (shown in detail, plan, and side view detached at Figures 6 and 7),
which has a slot he made longitudinally therein, the said slot fitting the square end e
of the barrel arbour, whilst the slide is free to traverse across the barrel in the
direction of its diameter. A small roller is carried in one end of the slide which
roller travels in the spiral groove d, and is drawn forcibly towards the centre of the
going barrel," so as to press against one side of the groove or against the side of
the spiral projection, as the case may be, by the action of two blade springs h, k,
made by preference in one piece with the cross arm f, or secured to the opposite ends
of the said cross arm by screws or otherwise. The inner or contiguous ends of the
said springs h, k, are caused to press against a projection (Figures 6 and 7) on that
end of the slide which is opposite to the roller i, thereby tending to draw the said
roller inwards, and consequently to exert more or less friction against one side of
the spiral groove or projection.
61
When the mainspring is in the act of being wound up the cross arm fand slide g
will be carried round along with the barrel arbour (the barrel remaining stationary),
and the roller i will travel along the spiral groove d until it arrives at the end of
the outer convolution thereof, as shown clearly in Figure 1. The opposite end of
the slide g is at the same time caused to approach the centre of the barrel, thereby
deflecting or compressing the two blade springs h, k, and bringing them into a state
of tension. The revolution of the barrel with its spiral groove or projection d during
the time the mainspring is gradually running down permits of the roller i gradually
approaching the centre of the barrel, as shown in Figure 3.
The action of this arrangement is as follows:-When the mainspring is fully
wound up, and is consequently exerting its greatest power, the blade springs h, k,
will be exerting their greatest strain upon the slide g, causing the roller i to act
upon the barrel at a point farthest removed from the centre thereof. As the barrel
revolves the power of the mainspring becomes weaker, and at the same time the
roller i, by gradually approaching the centre of the barrel, offers a gradually
diminishing resistance, the force of the blade springs k, k, also decreasing in pro- i

page_text: portion as the end of the slide g recedes from the centre of the barrel, and con-.
sequently a compensating action is obtained, which ensures an isochronous vibratory
motion of the balance. It is found in practice that the springs h, k, (the strength of
which should of course be proportioned to that of the mainspring) need only act
upon the slide g during the passage of the roller i along the two outer convolutions
of the spiral. The number of convolutions in the spiral & should correspond to the
number of revolutions made by the "going barrel" after the spring has been fully
wound up, allowing about one extra revolution for the purpose of straining the
With a view to obtaining a
spring sufficiently at starting, as is well understood.
further compensating action the spiral groove may, if desired, be made gradually
deeper towards the centre of the barrel, so that the farther the roller is from the
centre the greater will be the pressure exerted upon the bottom of the groove, the
said pressure diminishing in proportion as the roller approaches the centre of the
going barrel."
"
The herein-before described compensating arrangement is specially applicable to
what are known as " keyless watches," to which the ordinary fusee cannot be con-
veniently adapted.
The fact of the end of the slot in the slide g being brought to a stop by coming
in contact with the square end of the barrel arbour effectually prevents over-
winding, and consequently the usual contrivance known as the "
hitherto required for that purpose is also dispensed with.
stop work"
Having now described and particularly ascertained the nature of my said In-
vention, and the manner in which the same is er may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is, the combination with the "going bariel" of a watch, chro-
nometer, or spring clock of the spiral groove or projection d, the cross arm, with its
springs h, k, the slotted slide g, and roller i, when arranged to operate together
substantially in the manner and for the purpose herein-before described and illus-
trated by my Drawings.
In witness whereof I, the said Giuseppe Zaffira, have hereunto set my hand
and seal, this Fourth day of August, in the year of our Lord One thousand
cight hundred and seventy-six.
Witness,
EDWIN P. ALEXANDER,
Consulting Engineer and Patent Agent,
14, Southampton Buildings,
Chancery Lane,
W.C.
GIUSEPPE ZAFFIRA. (L.S.)