CERTAIN IMPROVEMENTS IN OR ON THE ESCAPEMENT FOR WATCHES
Year: 1817

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
LITHERLAND, of Liverpool, in the County of Lancaster, Watch Maker, do
send greeting.
WHEREAS His most Excellent Majesty King George the Third, by
His Letters Patent under the Great Seal of Great Britain, bearing date at
Westminster, the Twentieth day of February, in the fifty-seventh year of His
reign, did give and grant unto me, the said Richard Litherland, my exors,
aduiors, and assigns, His special license, full power, sole priviledge and
authority, that I, the said Richard Litherland, my exors, admors, and
assigns, during the term of years therein expressed, should and lawfully might
make, use, exercise, and vend, within England, Wales, and the Town of
Berwick-upon-Tweed, my Invention of "CERTAIN IMPROVEMENTS IN OR ON THE
ESCAPEMENT FOR WATCHES;" in which Letters Patent there is contained a
proviso obliging me, the said Richard Litherland, under my hand and seal,
to cause a particular description of the nature of my said Invention, and in
what manner the same is to be performed, by writing under my hand and
seal, to be inrolled in His Majesty's High Court of Chancery within six
calendar months next and immediately after the date of the said recited
Letters Patent, as in and by the same, relation being thereto had, may more
fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, I, the said
Richard Litherland, do hereby declare that my said Invention is an escape-
ment for the more correctly measuring and keeping of time, to be attached
to chronometers or marine timekeepers and pocket watches, and which is
described in the annexed Drawing, and set forth as follows, namely:-
A, the pallat wheel; B, the impelled pallat; C, the verge; D, the lifting
pallat (under the impelled pallat); E, the lifting pin on the impelled pallat
(when a lifting pallat is not used); F, the detent pallat, made with or without
a slender spring, longer than the detent pallat, so that the lifting pallat or
lifting pin may force open the spring instead of detent pallat when the balance
is moved in the direction of the dart
; G, the directing pallat being
fixed upon the same pivot or axis with the detent pallat; H, the detent; J, the
detent spring, made of balance spring wire; and K, the stud of the detent
spring. By a reference to the Drawing, supposing the balance to be at rest,
it will be observed that the tooth of the pallat wheel A locks a little upon the
detent II, and by the detent spring J gently pressing upon the directing
pallat G, keeps both the detent H and the detent pallat F (which are upon
the same pivot or axis) in the place or situation they appear in the Drawing,
the detent pallat lying or leaning a little from or off the centre of the verge
C of the impelled pallat. Now, as the balance, the impelled pallat, and the
lifting pallat or lifting pin are all upon the same pivot or axis, consequently they
will move all together; then let the balance be moved in the direction of the
by which the lifting pallat D or the lifting pin E, forcing upon
the detent pallat F, brings the detent H deeper into the space L of the pallat
wheel A; or when a spring is attached to the detent pallat, then the lifting
pallat D, or lifting pin E, forcing or pressing upon the spring instead of the
detent pallat, as before set forth, the detent H is not thereby moved any
deeper into the space L of the pallat wheel A, but the tooth of the pallat
wheel A is kept locked upon the detent EI, as is scen; when the balanco is
supposed at rest, [and the lifting pallat D or the lifting pin E having passed
and left the spring of the detent pallat F (and when a spring is not used then
having passed the detent pallat itself), the detent spring J, pressing or forcing
immediately upon the directing pallat G (as before described), brings the
detent II into its original place or situation, and whilst the returning motion
of the balance, by the reaction of the balance spring, brings back the lifting
pallat D or the lifting pin E against the spring of the detent pallat H (or when
a spring is not used against the detent pallat), and unlocks the pallat wheel A,
which before was held by the detent H, and gives it impulse to the balance,
durt A

page_text: and, so on in every succeeding vibration. And for chronometers or marine
timekeepers, instead of the directing pallat G, and detent pallat with its
spring F moving upon pivots or axis, I have contrived the detent pallat and
the detent to be both attached and fixed upon a straight elastic steel, made
fast at both ends vertically, S, S, by which there is no pivots, and consequently
no friction, except from the pallat wheel tooth A pressing upon the detent H;
and the clastic steel being made or worked flat, causes, when fastened at cach
end, a circular elasticity), so that when the lifting pallat D, or the lifting pin
E, as forced upon the detent pallat spring F, and having passed and left the
same, the detent H, by the circular elasticity of the straight steel, is brought
back into its original place or situation, there being a banking stud screw
to regulate the depth of the detent into the space L of the pallat wheel
A; and whilst the returning motion of the balance, by the reaction of the
balance spring, brings back the lifting pin E against the detent pallat spring
F, and unlocks the pallat wheel A and gives its impulse to the balance, and
so on in every succceding vibration, as before set forth. To adjust and
regulate the motion of the balance in heat and cold, I have contrived to fix
an elastic power or rod (curved or otherwise) to act upon the balance spring,
which clastic rod is composed of a limina of brass and steel, which gives it
the property of contracting or expanding, according to the degree of tempera-
ture. It is fastened to a stud on the potence plate, and has a moving slide
raised as a stud or head, and slit so as to admit of the elastic rod. The slide
is made with a groove to admit a pin to regulate its direction, and a screw to.
stay or hold it within any part of the space of the groove it may be moved in;
and as the slide either shortens or lengthens the elastic rod or power, and
corrects its contraction or expansion, so the regulation is adjusted and corrected
by its acting upon the balance spring accordingly, and is described as follows:-
See the Drawing M. The stud holds the elastic rod fast; N, the elastic rod;
O, the moving slide, slit at the top to admit the elastic rod through; R, the
screw to hold the rod in the slit or any part of the groove the slide may be
moved in; P, the pin that directs the slide; and Q, the screw to fasten the
slide.
In witness whereof, I have hereunto set my hand and seal, the Sixth
One thousand night hundred
RICHARD (L.s.) LITHERLAND.

page_text: AND BE IT REMEMBERED, that on the Sixth day of August, in the
year of our Lord 1817, the aforesaid Richard Litherland came before our
said Lord the King in His Chancery, and acknowledged the Specification
aforesaid, and all and every thing therein contained and specified, in form
above written. And also the Specification aforesaid was stampt according
to the tenor of the Statute made for that purpose: