A CERTAIN INSTRUMENT, MACHINE, OR MANUFACTURE APPLICABLE IN MECHANICS AS A BALANCE OR EQUIPOISE
Year: 1809

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
ISAAC HAWKINS, of Great Titchfield Street, in the County of Middlesex,
Machinist, 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 West-
minster, the Second day of November, in the fiftieth year of His reign, did,
for Himself, His heirs and successors, give and grant unto me, the said John
Isaac Hawkins, His especial licence, that I, the said John Isaac Hawkins,
my executors, administrators, and assigns, or such others as I, the said
John Isaac Hawkins, my executors, administrators, or assigns, should at any
time agree with, and no others, from time to time and at all times 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 "A CERTAIN INSTRUMENT, MACHINE, OR MANUFACTURE
APPLICABLE IN MECHANICS AS A BALANCE OR EQUIPOISE;" in which said Letters
Patent there is contained a proviso obliging me, the said John Isaac Hawkins,
by an instrument in writing under my hand and seal, particularly to describe
and ascertain the nature of my said Invention, and in what manner the same
is to be performed, and to cause the same to be inrolled in His Majesty's
High Court of Chancery within two calendar months next and immediately
after the date of the said recited Letters Patent, as in and by the same,
reference being thereunto had, will niore fully and at large appear.

page_text: NOW KNOW YE, that in complianco with the said proviso, I, the said
John Isaac Hawkins, do hereby declare that the nature of my said Inven-
tion, and the manner in which the same is to be performed, is described and
ascertained by and in the, Drawings in the margin of these Presents, and by
and in the following explanation thereof, that is to say :-
Instead of a weight commonly used to counterbalance or equipoise a lamp,
chandelier, lustre, window sash, window shutter, window blind, sliding mantle,
or blower of a stove, or any other weight requiring a counterbalance or equi-
poise, I employ a steel spring, such as in a spring clock is called the mainspring
(see Figure 1, a, a). I attach one end of the said spring to a fixed axis (6),
and after coiling this spring around the axis fusten it by the other end to a
barrel (c, c, c) which has rotation on the said axis after the manner the same
is done in a spring clock. Now it is well known, that if a small weight (d)
be suspended by a line or chain (e) to the circumference of this barrel, the
barrel will be turned a certain small distance, but to make it turn farther a
larger weight is necessary. This spring and barrel is therefore not an equi-
poise or balance, but requires an addition to constitute it such, for which
purpose I fasten to one end of the said barrel a fusce (see Figure 2. wherein
A is a view in a line with the axis; B is a view perpendicular to the axis;
(a, a) the axis; (b,b,) the barrel; (c, c,) the fuzee). This fuzee is so formed,
that when the spring is slack or nearly slack, and consequently very weak, the
line or chain (d), which supports the weight to be counterpoised (e), shall
hang near the axis; but as by the rotation of the barrel the spring is wound
up, and thus becomes stronger, the said line or chain shall recede upon the
fusee from the axis, and thereby procure a greater power of purchase upon
the spring, and this in such proportion as that the spring shall support any
given weight when hung to the line or chain in all situations. The same
effect may be produced by fixing the barrel instead of the axis, and letting
the fuzee with the axis be turned, instead of the barrel being turned. This
machine may be made of iron, brass, steel, or any kind of hard metal, or some
part or parts of metal, and others of wood or other bard substance; and in
order to bring it into action it must of course be fixed in some situation
capable of supporting its own weight, and the weight of the thing to be
balanced, and the whole machine may be concealed by any covering or
ornament which fancy may suggest. In certain confined situations it may be
convenient to put two or more machines on one fixed axis, for the purpose of
counterbalancing two or more windows, blinds, or weights of any description.
For some purposes it will be requisite to have two or more lines or chains,
and consequently to make the fuzce with double or multiple grooves (Figure 3),

page_text: or to have two or more fusees (sec Figure 4, which represents two fusees
having a barrel within shewn by dotted lines). For other purposes it may be
convenient (as in Figure 5) to put the spring and barrel (a) on one axis and
the fusce (6) on another, and to employ a line or chain (c) to connect them
together, as well as one (d, d.) going round a cylinder fixed to the fusee to
support the weight to be counterbalanced (e). This line is represented as
broken, to save room in the Drawing. (f, f) is a frame in which the whole
acts. For the blower of a stove, several plates of iron or brass are to be
hinged together and wound on a roller, within which roller is a spring of the
kind before mentioned. In this case, since the blower is a variable weight,
decreasing as it winds up, and increasing as it is pulled down, the thickness of the
blower itself, or of a rim on each edge of it, may form an equivalent to the
action of the fusee, by causing the blower to be suspended nearer to or farther
from the center of the roller, in such proportion as to be counterbalanced by
the spring at all heights. (Figure 6 represents a front, view of the blower.
(a, a, a, a,) the blower; (b, b, b, b,) the hinges; (c, c,) nobs to move it by.)
(Figure 7 is a profile view of the same blower, partly wound on the roller
which forms the axis. (a, a,) the jointed blower; (b), the roller; (c), the
nob.) The shape of the fusee must in all cases be determined by the varying
power of the spring and thickness of the line or chain. A simple rule to find
this shape is, to take account of the actual weight which the spring will support
at every half or quarter turn of the barrel, the weight being suspended from
the circumference of the barrel; multiply this weight by the radius of tho
barrel, and divide the sum by the weight designed to be suspended from the
fusco; the quotient will shew the distance at which the line or chain ought to
hang from the axis, and, consequently, will determine the shape of the fusee.
In the case of lamps were the quantity of oil will be greater at some times
than at others, and consequently the weight which is to be supported will
vary,
I introduce a small spring, Figure 8, g, pressing against the barrel or
fusee, or any other convenient part, to create a degree of friction, to prevent
the lamp or other weight preponderating when full of oil, and to hinder tho
counterbalancing spring from being too powerful when the oil is burnt out, or
the burner removed, or the weight decreased by any other means. I use the
spring to create friction in any case where the counterbalanced weight is
liable to encrease or diminution.
The chief advantage as well as novelty of my Invention consists in com-
bining a spring with a snail or fusee, for the purpose of counterbalancing a
weight; and as this has not heretofore been done, I claim the right of doing it
in all the various forms which fancy or convenience may dictate, a number of

page_text: which are shown in the Drawings in the margin of these Presents, and which
are in part before referred to. Figure 9 shews the machine with single fusec,
in a convenient form for suspending a lamp, lustre, or other weight. Figure 8,
before referred to, is a view in a line with the axis of the same machine as
that shewn in Figure 9, shewing the end of the barrel and so much of the
fusee as exceeds the diameter of the barrel; the letters refer to the same parts
in both Figures. (a, a,) the barrel; (b, b,) the fusee; (c) the line or chain
to which the lamp, lustre, or weight is to be suspended; (d, d,) the axis;
(e, e, e, c,) the frame into which the axis is fixed; (f) a screw for fixing the
whole machine to a ceiling or other place. Figuro 10 shews the application
of the machine to suspend a window sash. (a), the machine fixed, and to be
concealed in the top of the window frame; (b, b,) the lines coming from two
fusees attached to one spring and barrel, which lines go over pullies (c. c); these
pullies are fixed to the two extremities of a piece forming the under sides of
the top of the window frame. The lines pass down through holes at the end
of this piece, and fix to the sash (d) on each side. (e, e, e, e, represent the
window frame.) In a similar manner I apply the machine to counterbalance
a coach window, or other similar weight or weights.
In witness whereof, I, the said John Isaac Hawkins, have hereunto set
my hand and seal, this Second day of January, in the year of our
Lord One thousand eight hundred and ten.