IMPROVE MENTS IN PARTS OF WATCHES AND SUCH LIKE TIMEKEEPERS
Year: 1878

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the County of
Middlesex, Patent and Registration Agent, for the Invention of " IMPROVE
MENTS IN PARTS OF WATCHES AND SUCH LIKE TIMEKEEPERS." A communi-
cation from abroad by Frederic Fitt, of Ottawa, in the Province of Ontario, in
the Dominion of Canada.
led the 16th August 1878, and dated the 21st February 1878.
PROVISIONAL SPECIFICATION left by the said William Brookes at the Office
of the Commissioners of Patents on the 21st February 1878.
WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middlesex, Patent
and Registration Agent. "IMPROVEMENTS IN PARTS OF WATCHES AND SUCH LIKE
TIMEKEEPERS." A communication from abroad by Frederic Fitt, of Ottawa, in the
Province of Ontario, in the Dominion of Canada.
The object of the Invention is to obviate the liability of damage to the movement
arising from the breaking of the mainspring, and the consequent recoil of the great
wheel. This great wheel, as hitherto made, has usually formed a solid portion of
the barrel, and has consequently been liable to serious damage as the result of the
breaking of the mainspring. When such an accident occurred a tooth might be
broken, or a leaf be forced out of the centre wheel pinion, or some injury to the
simpler works be likely to follow.
In the present Invention the barrel is made detachable from the great wheel.
When therefore the mainspring breaks the barrel necessarily separates itself from
the great wheel, leaving the latter stationary and quiescent in the pinion of the
centre wheel. The barrel itself recoils within the great wheel into which it is sunk,
thus instantaneously releasing the entire movement from the effect of the reaction.
The safety of the simpler movements from any possible injury arising from the
breaking of the mainspring is likewise thus secured.
The advantages of the improvements are in the simple and precise action,
effectually preventing all damage to the movement beyond the breaking of the
mainspring. For this purpose the great wheel is connected to the barrel by dogs or

page_text: catches, the ends of which are so spread as to dovetail or slide in and out of the
slots of the openings for them in the great wheel, and yet to allow free back action
or recoil to the barrel when required; the hub or boss shoulder of the great wheel
is high enough to allow the barrel to rise just sufficiently from the great wheel to
free the dogs therefrom. There is a square to the pivot of the barrel arbour on 5
which the great wheel works. There is also an opening fitting on the centre
shoulder or hub of the great wheel, and it is on that centre shoulder or hub the
opening of the barrel fits and recoils, the barrel being sunk into the great wheel.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Brookes in the Great Seal Patent Office on the 20th August
1878.
"
WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middlesex, Patent
and Registration Agent. IMPROVEMENTS IN PARTS OF WATCHES AND SUCH LIKE
TIMEKEEPERS." (A communication from abroad by Frederic Fitt, of Ottawa, in the
Province of Ontario, in the Dominion of Canada.
The object of the Invention is to obviate the liability of damage to the movement
arising from the breaking of the mainspring and the consequent recoil of the great
wheel. This great wheel, as hitherto made, has usually formed a solid portion of the
barrel, and has consequently been liable to serious damage as the result of the
breaking of the mainspring. When such an accident occurred a tooth might be
broken or a leaf be forced out of the centre wheel pinion, or some injury to the
surface works be likely to follow.
In the present Invention the barrel is made detachable from the great wheel.
When therefore the main spring breaks the barrel necessarily separates itself from
the great wheel, leaving the latter stationary and quiescent in the pinion of the
centre wheel. The barrel itself recoils within the great wheel into which it is sunk,
thus instantaneously releasing the entire movement from the effect of the reaction.
The safety of the simpler movements from any possible injury arising from the
breaking of the mainspring is likewise thus secured.
The advantages of the improvements are in the simple and precise action,
effectually preventing all damage to the movement beyond the breaking of the
mainspring.
But that the Invention may be fully understood, I will by the aid of the accom-
panying Drawings proceed to describe means by which the Invention as communi-
cated to me may be fully understood.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a face view of the great wheel attached to the barrel by the dogs or
catches.
Figure 2 is a face view of the barrel with the great wheel detached therefrom;

page_text: Figure 4 is an isometrical view of the great wheel, showing the interior and the
openings.
Figure 5 is an isometrical view of the great wheel.
Figure 6 is a bottom view of the barrel reversed.
a, a, a, Figures 1 and 2, are the dogs or catches, the ends of which are so spread as
to dovetail or slide in and out of the slots of the openings b, b, b, in the great
wheel, and to hold fast as shewn. These dogs or catches a, a, a, are shaped in such
a manner as to allow free back action or recoil to the barrel when required, the hub
or boss shoulder (e, Figure 4) of the great wheel being high enough to allow the
barrel to rise just sufficiently from the great wheel to free the dogs therefrom.
b, b, b, (Figure 4) are the openings in which the dogs (Figures 1 and 2) dovetail,
slide, catch, and hold fast the great wheel to the barrel or release it therefrom, as
described, should the mainspring break.
c (Figure 2) is the square of the pivot of the barrel arbour on which the great
wheel works.
d (Figure 2) is an opening fitting on the centre shoulder or hub of the great
wheel.
c (Figure 4) is the centre shoulder or hub on which the opening (d, Figure 2) of
the barrel fits and recoils, the barrel being sunk into the great wheel.
Having thus described the nature of the said Invention, and the means employed
in carrying the same into effect, as communicated to me, I would have it understood
that what I claim is,―
First. The sinking of the barrel into the bed of the great wheel and its
detachability therefrom, substantially as described.
Second. The centre opening d in the barrel, and its dogs or catches a, and their
action, substantially as described.
Third. In combination with the detached great wheel having its bed sunk, the
boss or shoulder c and the slots of the openings d, substantially as described.
In witness whereof, I, the said William Brookes, have hereunto set my hand
and seal, this Nineteenth day of August, in the year of our Lord One
thousand eight hundred and seventy-eight.
WILLIAM BROOKES