IMPROVEMENTS IN THE MODE OF PRODUCING MECHANICAL MOTION
Year: 1866

page_text: LETTERS PATENT to William Brookes, of 62, Chancery Lane, in the
County of Middlesex, Civil Engineer and Patent Agent, for the Inven-
tion of "IMPROVEMENTS IN THE MODE OF PRODUCING MECHANICAL MOTION."
-A communication from abroad by Henry Smith, of Salem, in the
County of Essex and State of Massachusetts, in the United States of
America.
Sealed the 20th July 1866, and dated the 23rd January 1866.
PROVISIONAL SPECIFICATION left by the said William Brookes at the
Office of the Commissioners of Patents, with his Petition, on the
23rd January 1866.
I, WILLIAM BROOKES, of 62, Chancery Lane, in the County of Middlesex,
Civil Engineer and Patent Agent, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MODE OF PRODUCING MECHANICAL MOTION,"
(communicated to me from abroad by Henry Smith, of Salem, in the County
of Essex and State of Massachusetts, in the United States of America,) to
be as follows:-
The Invention relates to a mode of producing a regularly increasing or
decreasing intermittent or other rotary motion. To the periphery or outer
edge of a wheel are applied teeth which take into the teeth of a pinion. On
the face or other surface of this wheel are applied other teeth progressing
spirally from towards the centre to the outer diameter thereof, thus forming

page_text: a scroll or volute of teeth, which is taken into by the teeth of another pinion
which is capable of a sliding motion to and from the axis of the scroll of
teeth to enable it to follow the course of the teeth of the scroll. The teeth
of the scroll or volute may be formed either upon a plain or conical surface,
and either a bevil or a spur pinion may be employed to gear with them.
A series of volutes, racks, and pinions may be so combined as to make
the rotary motion continuous or varied in any desired manner, as well as
intermittent, by causing the travelling pinion to be thrown out of gear at
certain times and changed for another.
One application of the Invention is to raising and lowering window blinds
or shades. For this purpose one end of the blind or shade roller receives a
stud or axis, upon which is applied a pinion, the teeth of which take into
those on the periphery of the wheel having the scroll or volute of teeth,
whilst the teeth of the volute or scroll are taken into by the teeth of a
pinion, the axis of which is acted upon by a coiled spring and is capable of
a sliding motion, in order that the teeth of the pinion may follow the course
of the volute, and thereby equalize the power of the spring. The volute
gear is arranged in relation to the spring that the force exerted by the weight
of the blind or shade balances that of the spring, and the blind or shade
thereby remains in any position in which it may be placed.
Another application of the improvements is to operating window sashies
and doors. In this case the teeth at the periphery of the scroll wheel take
into the teeth of a rack on the side or edge of the sash or door. The axis
of the scroll or volute may be supported in a frame or lever, so as to be
capable of disengagement at pleasure with the teeth of the rack when
adjustment of the sash or door has been effected. The gear may be set
fast when desired by a sliding bolt. Amongst many other devices this volute
gear is also applicable to clocks, watches, musical instruments, and automatical
sewing machines.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Brookes in the Great Seal Patent Office on the
23rd July 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
BROOKES, of 62, Chancery Lane, in the County of Middlesex, Civil Engineer
and Patent Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by. Her Letters.

page_text: .
Patent, bearing date the Twenty-third day of January, in the year of our
Lord One thousand eight hundred and sixty-six, in the twenty-ninth year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said William Brookes, Her special licence that I, the said William
Brookes, my executors, administrators, and assigns, or such others ns 1, the
said William Brookes, 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
"IMPROVEMENTS IN THE MODE OF PRODUCING MECHANICAL MOTION," a communi-
cation to me from abroad by Henry Smith, of Salem, in the County of Essex
and State of Massachusetts, in the United States of America, upon the con-
dition (amongst others) that I, the said William Brookes, 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 same 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 Brookes, do hereby declare
the nature of the said Invention, and in what manner the same is to Le
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say:-
The first part of the Invention, and that which I consider of the greatest
importance, as it is applicable to so many varied purposes and is also the
foundation of the subsequent parts of the improvements to be berein-after
explained, consists in a new method of producing a regularly increasing or
decreasing intermittent or other rotary motion. Such a motion has long been
sought for in machinery, but has never previously been successfully attained,
except by very complicated arrangements.
To explain the Invention more in detail I will proceed as follows:-In lieu
of an ordinary gear wheel there is used one the teeth of which are formed or
wound in the form of a spiral or volute. With this volute or scroll gear a
pinion is made to engage, and power can be applied either to teeth formed
on the periphery of the volute gear or to the spirally arranged teeth of the
volute gear itself, the pinion that engages with the teeth of the latter being
necessarily susceptible of such a motion as will allow the said pinion to both
approach to and recede from the centre of the scroll rack. It will be. obvious

page_text: that the teeth of the volute gear may be formed either upon a plane or conical
surface, and that either a bevel or spur pinion may be used.
In Sheet 1, Figure 1 represents an elevation of the improvements; Figure
2 is a central horizontal section of the same; Figure 3 is a plan or top view.
c, c, in the Drawings represent a gear wheel, upon the face of which are
formed apertures or teeth d, d, arranged in the shape of a volute. Upon the
periphery or circumference of the wheel c, c, are teeth b; b, with which a
pinion q, q, engages. With the volute gear c, c, engages a pinion h, h
'
attached to a shaft i, i, that turns in bearings m, m, and is free to travel
longitudinally to and from the centre of the volute gear c, c. From this
description it will be seen that on applying power to the pinion q, q, for
instance, the shaft i, i, will revolve with a constantly increasing velocity as its
pinion h, h, travels from the centre to the outer circumference of the volutė
wheel c, c, and with a constantly decreasing speed while the pinion h, h,
moves towards the centre of the said volute wheel c, c, because in the first
case the leverage or diameter of the volute gear c, c, in its action upon the
said pinion h, h, is constantly increasing, and in the latter case constantly
diminishing.
It will be apparent that when power is applied to the shaft i, i,
instead of to the shaft r, r, of the pinion q, q, that the effect upon the latter
will be precisely the reverse, because the volute wheel c, c, will receive its
slowest velocity while the pinion h, h, is engaged with its outermost teeth,
which velocity will of course increase as the pinion h, h, approaches the centre
of the volute gear c, c.
It will be evident that by any suitable arrangement of devices such
as are well known to machinists a series of volutes, racks, and pinions
may be so combined as to make the rotary motions continuous or varied in
any desired manner, as well as intermittent, that is, by causing the travelling
pinion to be thrown out of gear at any stated point of contact with the volute
wheel, and another pinion being made to engage therewith. It will also be
obvious that in case the teeth of the volute wheel are arranged upon, a conical
periphery that the shaft of the travelling pinion must be so arranged and allowed
to play in such a manner as to always keep the teeth of its pinion engaged
with those of the volute gear.
The second part of the Invention relates to the application of the foregoing
described apparatus to window shades for the purpose of operating them, and
is represented in Sheet 2 of the accompanying Drawings; Figure 1 being 'a
vertical longitudinal section, and Figure 2 a horizontal longitudinal section
of my improved apparatus.

page_text: a, a, a, in the Drawings represent the box or framework of a window in.
which is inserted the apparatus, which consists of a gear b, b, with which is
formed a volute rack or gear c, c, the teeth being placed in the form of a
scroll or volute, as represented by the holes d, d, d; e, e, is a shaft attached to.
the volute gear c,
and which turns in standards f. f. formed by the front.
and rear plates of the frame g, g, of the apparatus. A pinion h, h, with circular
pointed teeth engages with the volute gear c, c, and operates the same by
means of the power given to a shaft i, i, to which it is attached by a coiled
spring k, k, contained in a case 1, 1, one end of the spring k, k, being fastened
to the end of the shaft i, i, which passes through the case l, l. Formed to
the case 1, 1, and attached to the shaft i, i, by standards m, m, which form
a bearing for the shaft i, i, is a slide n, n, formed with a slot o, o, which
works on a pivot p, for the purpose of moving backwards and forwards the
shaft i, i, and case 1, l, to suit the position of the pinion h, h, which works in
the volute gear c, c. Engaging with the gear b, b, on the periphery of the
volute gear c, c, is a pinion 9, q, attached to a shaft r, r, the outer end of
which shaft is formed square to receive one end of a shade roller s, s. The
sbaft r, r, turns in a bearing t, t, formed by the end of the plate or frame g, J.
A pivot u is formed on the other end of the shade roller s, s, and turns in
a standard v, v, attached to the opposite side of the window frame a, a.
The operation of the improvements as applied to window shades is as
follows The pinion g, q, is turned by drawing down the shade w, w, which
is fastened to the roller s, s, fitted on the square end of the shaft r, r, thereby
revolving the volute gear c, c, with whose outer gear b, b, the pinion q, q,
engages; the volute gear c, c, in turn operates the pinion h, h, and shaft i, i, to
which it is attached, thereby coiling up the spring k, k, attached to one end of
the shaft i, i, and enclosed in the case 1, 1. As the volute gear c, c, revolves
it draws laterally the pinion h, h, and slide n, n, towards its centre, thus
giving the pinion h, h, more and more leverage in its relation to the
pinion q, q, and thereby equalizing the increasing power of the spring k, k,
as it is coiled up. The volute gear c, c, and its pinion h, h, are arranged in
such a manner with regard to the spring k, k, that the force exerted by the
weight of the shade w, w, just balances the spring k, k, and consequently the
shade w, w, remains in any position in which it is placed. When the
shade w, w, is lifted up or its weight relieved, the action of the spring k, k,
upon the shaft i, i, causes the pinion h, h, to revolve the volute gear c,.c,
which turns the shaft r, r, connected with the roller s, s, and thereby winds
up the shade w, w, attached to the rollers, 8.
The third part of the Invention relates to an apparatus similar to the above

page_text: described applied to window sashes for the purpose of operating them, and is
represented in Sheet 3 of the accompanying Drawings; Figure 1 being a
front elevation of a window sash with my improved device for operating the
same, Figure 2 a detail rear view of said device, and Figure 3 a horizontal
Jongitudinal section.
a, a, a, in the Drawings represent the framework of a window, in which
is fitted a sash 61, 6; on the side of the sash b', 6', is a rack c¹, c', engaging
with which is a gear b, b, formed on the outer circumference of a volute
gear c, c, which turns on a shaft or pivot, e, e, supported by one side of
the frame g, g. Engaging with openings d, d, d, which form the scroll of
the volute gear c, c, is a pinion h, h, attached to a shaft i, i, to the end
of which shaft i, i, is fastened one end of a coiled spring k, k, enclosed in a
case 1, l, through which case the shaft i, i, extends. Formed on the case 1, 1
and attached to the shaft i, i, by .standards m, m, is a slide n, n, formed with
a slot o, o, which works on pivots p, p, for the purpose of moving backwards
and forwards the shaft i, i, and case 1, 1, to suit the position of the pinion h, h,
which works in the volute gear c, c. Attached to the centre of the volute
gear c, c, at the rear, and pivotted to the standard f, f, formed by one side of
the frame g, g, is a curved lever arm a, a, for the purpose of engaging the
gear b, b, with or disengaging it from the rack c', c', after the frame g, g, is
adjusted to the window frame a, a. By sliding in an adjustable bolt y, y, so
made as to engage with the gear b, b, the sash b', 61, is securely fastened in any
desired position.
The operation of the improved device for operating window sashes is as
follows: When the sash b₁, b, is drawn down the rack c', c', fitted in
its side, engages with the gear b, b, formed on the periphery of the volute
gear c, c, thereby revolving the volute gear c, c, the pinion h, h, engaging in
the openings d, d, d, formed in the volute gear c, c, and the shaft i, i, attached
to the pinion h, h, and consequently coiling up the spring k, k, attached to one
end of the shaft i, i, and enclosed in the case 1, 1. As the volute gear c, c,
revolves it draws laterally the pinion h, h, and slide n, n, towards its centre,
thus giving the pinion h, h, more and more leverage in its relation to the
rack c', c, and thereby equalizing the increasing power of the spring k, l, as
it is coiled up. The volute gear .c, c, and its pinion h, h, are arranged in such a
manner with regard to the spring k, k, that the force exerted by the weight of
the sash b', 6', just balances the spring kc, k, and consequently the sash, U,
remains in any position in which it is placed. When the sash b', b, is raised
or its weight relieved, the rack c', c', engages with the gear b, b, and
revolves the volute gear c, c, and consequently turns the pinion h, h, attached

page_text: to the shaft i, i; and the sash is equally balanced and held in any desired
position by the power exerted by the spring k, k, upon the pinion h, h, volute
gear c, c, &c.
In the above-described arrangements of a window shade and a window
sash the most essential feature consists in the functions which the volute gear
and its pinion bear to the coiled spring, the leverage afforded by the said
gear and pinion being an exact counterbalance to the power of the spring, so
that the force exerted by the latter, instead of being as in ordinary cases
variable, is always and uniformly the same.
Among many devices to which the Invention is applicable may be
mentioned the following, viz., producing the desired movements in clocks
and watches, and running melodions and sewing machines automatically.
In witness whereof, J, the said William Brookes, have hereunto set my
hand and seal, this Nineteenth day of July, in the year of our Lord
One thousand eight hundred and sixty-six.
WILLIAM BROOKES.
(L.S.)