AN IMPROVED CONSTRUCTION OP LEVER WATCH MOVEMENTS
Year: 1867

page_text: LETTERS PATENT to William Borthwick Smith, of the City of Coventry,
Watch Manufacturer, for the Invention of "AN IMPROVED CONSTRUCTION
OP LEVER WATCH MOVEMENTS."
Sealed the 8th February 1868, and dated the 28th August 1867.
PROVISIONAL SPECIFICATION left by the said William Borthwick Smith
at the Office of the Commissioners of Patents, with bis Petition, on the
28th August 1867.
1, WILLIAM BORTHWICK SMITH, of the City of Coventry, Watch Manufacturer..
do hereby declare the nature of the said Invention for "AN IMPROVED.
CONSTRUCTION OF LEVER WATCH MOVEMENTS," to be as follows:-
The Invention relates to improvements in the construction of the frame-or
supporting parts of lever watches and the application thereto of a T-lever
escapement (detached or otherwise) working in a straight line or. at. a slightly.
divergent angle, and having the same action as in the ordinary construction.
The frame is similar to a 2-plate frame, except that the cock. below the
balance to carry the escapement is dispensed with (or in an alternative plan
it is only used to carry the pallets); the bar or pillar plate into which the
balance staff is pivotted is also dispensed with, and the balance staff is pivotted
into the pillar plate. The barrel is made-deeper-by-the-thickness-of-the-top-
plate, and is carried by a bar on the top plate the same as in-full-plate-move-
ments. A bar is also fixed at the extremity of and beyond the top plate-

page_text: (opposite the balance) to which at the one end it is screwed and held in place
by two steady pins, and at the other end is screwed to an extra pillar. This
bar is intended to receive the pallets and pallet wheel or the pallet wheel
only, and to allow of their detachment from the watch either together or
separately without displacing the roller or balance staff or any of the train of
wheels. The train of wheels, detent works, maintaining power, and other
parts are, with certain slight modifications, like those in the ordinary lever
movement. The
The pallets are also constructed upon the same principles as the
pallets of the ordinary detached' lever escapement, but with. the arrangement
for a lengthened lever, and the size of the roller is increased proportionately
to the increased. length of the lever, except so far as this is obviated by the
pivotting of the pallet staff. The roller is to be collected with the ruby pin
on the under side working into the lever, which will also be pinned on the
under side of the pallets, but in an alternative plan the pallet wheel will be
mounted below the pinion into which the fourth wheel works.
The advantages to be obtained by the use of this Invention are, the simpler
construction and lower cost of movement; the greater freedom for the works
(especially the escapement), allowing it to be finished at much less cost; the
facility given for detaching the escapement (wholly or in part) for repairs or
cleaning without displacing any other part of the works; the greater length
of the arbors of the escapement, giving a steadier action and less liability to
errors arising from side shake of the pivots in holes; the facility given for
detaching the barrel in case of a broken mainspring requiring to be removed
and replaced; the facility for removing the bar over the barrel in order to
engrave thereon the name of the vendor or owner of the watch at small cost,
lastly, with the flatness of a 3-plate frame the watch will take as deep and
strong a spring as, a full plate frame, and with hollow pinion will allow of the
hands being set from the back.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Borthwick Smith in the Great Seal Patent Office on $
the 28th February 1868.
. TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BORTHWICK SMITH, of the City of Coventry, Watch Manufacturer,' send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters S
Patent, bearing date the Twenty-eighth day of August, in the year of our Lord

page_text: One thousand eight hundred and sixty-seven, in the thirty-first year of Her reign;
did, for Herself, Her heirs and successors, give and grant unto me, the said
William Borthwick Smith, Her special licence that I, the said William Borth-
wick Sniith, iny executors, administrators, and assigns, or such others as I, the
said William Borthwick Smith, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter 'during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"AN IMPROVED CONSTRUCTION OF LEVER WATCH MOVEMENTS," upon the condition
(amongst others) that I, the said William Borthwick Smith, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, should particularly describe and ascertain the nature of the
said Invention, and in what manner the same was to be performed, and
cause the saine to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.
NOW KNOW YE, that I, the said William Borthwick Smith, do hereby
declare the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawing hereunto annexed,
and to the letters and figures marked thereon (that is to say) :-
:-
This Invention relates to improvements in the construction of the frames of
lever watches, and to the application thereto of a T-lever escapement.
In the accompanying Drawing I have shewn the improved frame in various
forms, the same main idea being however retained in all, viz., giving increased
facility for removing the escapement, either wholly or in part, for repairs or
cleaning without displacing any other part of the works.
.
Figures I., II, and III. show the application of the first part of the Invention
to three forms of frame, affording facility for the detachinent of the escape-
ment complete; Fig. IV. shews the arrangement for the separate detachment
of the parts of the escapement; and Fig: V. shows on an enlarged scale the
detached lever escapement specially adapted for watch movements arranged
as herein-after described. The figures and letters of reference refer to like
parts in all the Figures.
1 is the top plate; 2 is a bar set over the barrel and connected securely by
Come to the ton plate: 3 (Figures 1., H., and III.) is the bar for supporting

page_text: the escape or pallet wheel) for taking the staff of the escape or pallet lever;
4 is the cock or its equivalent for supporting the balance arbor or staff.
A is the barrel hole in the bar 2; B, the fusee or great wheel hole in the
plate 1; C is the hollow centre wheel hole; D, the third wheel hole; and E,
the fourth or seconds' wheel hole; F is the pallet wheel hole in the plate 3;
and G is the pallet staff hole; H is the balance staff hole in the cock 4; I is
the barrel; N is the pendulum spring stud; O is the regulator stud (Fig. II.);
P is the pillar plate outline; Q, dog screws for cap; R, pillars; S, screws.
In Fig. V., X, X, are the escapement pallets; Y is the pallet staff, and Z
is the lever. The frame it will be seen resembles a three-quarter plate frame
as to the arrangement of the train of wheels and sinking the balance below
level of the top plate, but the cock below the balance (Plans I., II., and III.)
to carry the escapement is dispensed with, or, as shewn in Plan IV., only used
to carry the pallets. The bar on the pillar plate, into which the balance
staff is pivotted, is also dispensed with, and the balance staff is pivotted into
the pillar plate. The barrel (Figures I., II., and IV.) is made deeper than
usual by the thickness of the top plate, and is carried by the bar 2 on top
plate, the same as in full-plate movements. Fixed to the extremity of the top
plate (opposite the balance) and projecting beyond it is the bar 3, to which
at the one end it is held in place by screw and steady pins, and at the other
end rests upon the shoulder of and is screwed to an extra pillar (R', Figures
I. and III.,); or the bar is fixed over a hollow filed out of the top plate by
screws only (see Figures II. and IV.). The fourth pillar R', in Fig. I. would
be higher than the other pillars by the thickness of the top plate. The bar 3
which receives the pallet and pallet wheel (as in Figures I., II., and III.),
or the pallet wheel only, as in Fig. IV., allows of their detachment without
displacing the balance staff or any of the train of wheels, the top plate being
cut away for that purpose where shewn by black dotted lines beneath the escape
bar, on removal of which these parts are readily detached. Neither con-
struction would add to the thickness of the watch to any extent as compared
with the English three-quarter plate movement. The train of wheels, detent
works, maintaining power, fusee compensation, hollow centre pinion, and
other parts would with slight modifications be similar to the same respective
parts in the ordinary English lever watch movement. In relation to the
specialities in the several arrangements of frame I would remark that Fig. I.
shows the bar 3 fixed at one end to a screw pillar R₁, and at the other end by
a screw S¹ (and two steady pins) to the top plate. The shoulder of the pillar R¹
stands on a level with the top plate.
Fig. III. shows the same mode of fixing and detaching the bar 3, except

page_text: that the top plate is made thicker and the escape bar countersunk into it at
the edge and fixed by two small screws S¹, S', and one or two steady pins.
The barrel bar is also dispensed with, and by this arrangement the top plate
is all made flush on the top and specially adapted for dome-cased work.
Fig. II. shews an arrangement (specially adapted for being capped and
fitted in consular cases) whereby both cocks are dispensed with and two bars
substituted. The top plate is filed away round the holes G and F, into which
the escapement is pivotted to allow of its detachment when the bar 3 is removed
the same as in the other constructions. This construction would be fully capped
round the rim and over space I opposite balance and escapement at small cost,
the cap being fixed by dog screws Q, Q, or with bolt and spring in the ordinary
way, and it will admit of being indexed in two ways, either with bow sunk on
top of bar, where shown by blue circle round balance staff hole, with the
tail cranked under cap, and a nib or stud standing up through the slit in the
cap at O whereby it would be regulated, or by sinking the bow on the under
side of the bar where shown by red dotted circle round the balance staff bole
with the tail passing under cap in the one direction for curb pins to be pinned
in, and in the opposite direction with index sunk on the under side of the bar
and sliding on top plate, as shewn by red marked index, opposite the centre
wheel hole. The pendulum stud would be plugged in at N, so that it might
be knocked out and replaced without altering the regulator or unpinning the
pendulum spring. The black dotted circle round, balance staff hole shows
hollow turned out of the top plate for pendulum spring to work in, the balance
working below the top plate.
In the construction shewn at Figures I., II., and III. the contrivance for
complete separate detachment of the escapement would be the same, and the
escapement pitched in the same manner.
.
Fig. IV. shows a modified arrangement whereby the escapement would be
detached in two parts, the pallet staff being pivotted into a cock below balance,
the same as in three-quarter. plate movements (but the pallets pitched for
acting in straight line), and the pallet wheel only (or pallet wheel and fourth
wheel) pivotted into and detached by means of bar 3, which being required
for one staff only may be firmly fixed to the top plate only by screw S¹ and
two steady pins. This plan shews the click and ratchet on top plate. The
plans shewn at Figures I., III, and IV., would be indexed and regulated by
spring power in the ordinary manner.
Fig. V., shows a pair of pallets and lever of a detached lever escape-
ment, as the same would be constructed and pitched for adaptation to the

page_text: pallets under the pallet wheel in order to balance it on both sides (fore and
aft) of the pallet staff hole. The pallets would be made in like manner, and
upon the same principles as the ordinary lever pallets, but (for adaptation to
Plans I., II, and III.) with rather less draught on the pallets, and rather
larger roller in order to compensate for the increased length of lever. The
roller would be colletted with the ruby pin on the under side working into the
lever, which would also be pinned on the under side of the pallets. This lever
escapement is so mounted that its centre of motion will lie in a line drawn
from the centre of the pallet wheel to the centre of the balance wheel, or very
near thereto.
Having set forth the nature of my Invention of an improved construction
of lever watch movements, and explained the manner of carrying the same
into effect, I wish it to be understood that under the above in part recited
Letters Patent I claim,-
Firstly. The means above described for facilitating the removal of the
pallet wheel and pallet lever together, as in Figures I., II., and III., or
separately as in Fig. IV., in movements constructed on the three-quarter plate
principle with the balance clear of the centre wheel hole, and sunk below
level of the top plate without displacing any other parts of the movement.
Secondly. The application to watch movements so constructed of the detached
lever escapement.
In witness whereof, I, the said William Borthwick Smith, have hereunto
set my hand and seal, the Twenty-sixth day of February, in the year
of our Lord One thousand eight hundred and sixty-eight.
W. BORTHWICK SMITH. (L.S.)