IMPROVEMENTS IN APPARATUS FOR RAISING WEIGHTS
Year: 1871

page_text: LETTERS PATENT to Theodore Grace, of Bristol, in the County of
Gloucester, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
RAISING WEIGHTS."
Sealed the 25th June 1872, and dated the 27th December 1871.
PROVISIONAL SPECIFICATION left by the said Theodore Grace at the
Office of the Commissioners of Patents, with his Petition, on the
27th December 1871.
I, THEODORE GRACE, of Bristol, in the County of Gloucester, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
APPARATUS FOR RAISING WEIGHTS," to be as follows :-
This Invention consists in a combination of mechanism for the
purpose of raising weights, whereby certain disadvantages attendant
upon some of the contrivances hitherto adopted are avoided.
In those arrangements which have been constructed upon the
principle of the well-known "sun and planet" motion, or modifications

page_text: thereof, and which it is unnecessary to describe, the mechanism has to
a certain extent been rendered inoperative and the weight held in
suspension by reason of the pressure of the cogs or teeth of the wheels
employed binding one against another, thereby causing an excessive
amount of friction. The Inventions for which Letters Patent have been
granted to William Eades and William Thomas Eades, bearing date the
22nd day of June, 1866, No. 1672, to Jonathan Pickering, bearing date
the 3rd day of April, 1867, No. 990, to Thomas Moore, bearing date
the 26th day of February, 1869, No. 594, and to Thomas Moore and
Charles Arthur Head, bearing date the 30th day of October, 1869,
No. 3157, may be mentioned as examples.
The present Invention partially or entirely obviates this evil, and
provides a more generally useful apparatus. This is effected by substi-
tuting a differential pulley for the lifting pulley ordinarily employed in
such cases, and using the same in connection with the other portions of the
apparatus. An endless chain or an equivalent therefor is passed over the
differential pulley, the same forming a loop from the two pulleys, into which
loop a sheave wheel provided with a hook is placed. The weight to be
raised is attached to the hook as at present in connection with differential
pulleys, and the apparatus is worked as will be well understood by
persons conversant with mechanical appliances.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-seventh day of December, One
thousand eight hundred and seventy-one, in the thirty-fifth year
of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Theodore Grace, Her special licence that
I, the said Theodore Grace, my executors, administrators, and assigns,
or such others as I, the said Theodore Grace, my executors, adminis-
trators, 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 APPARATUS
FOR RAISING WEIGHTS," upon the condition (amongst others) that I, the
said Theodore Grace, 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

page_text: bearing date the 22nd day of June, 1866, No. 1672, to Jonathan
Pickering, bearing date the 3rd of April, 1867, No. 990, to Thomas
Moore, bearing date the 26th day of February, 1869, No. 594, and to
Thomas Moore and Charles Arthur Head, bearing date the 30th day of
October, 1869, No. 3157, may be mentioned as examples.
My said Invention partially or entirely obviates the evil above
referred to, and provides a more generally useful apparatus. This is
effected by substituting a differential pulley for the lifting pulley
ordinarily employed in such cases, and in using the same in connection
with the other portions of the apparatus. An endless chain or an
equivalent therefor is placed over the differential pulley, the same
forming a loop from the two pulleys into which loop a sheave wheel
provided with a hook is placed. The weight to be raised is attached to
the hook, as at present in connection with differential pulleys, and the
apparatus is worked as will be well understood by persons conversant
with mechanical appliances.
In some cases a rope may be used instead of a chain, and more
especially when this arrangement is used in connection with a windlass.
I
may also observe that the differential pulley may be made with
indentations or recesses therein, or with projections thereon for the
purpose of affording a better holding for the chain employed. Instead
of an endless chain being used an ordinary chain may be passed over the
pulley and arranged in any convenient manner.
The above description shews the general character and nature of my
said Invention, and I will now proceed to refer to the annexed Drawings
from which the manner in which the apparatus is constructed will be
more clearly understood.
Figure 1 is a side elevation, and Figure 2 is an end elevation of the
apparatus, the same letters of reference indicating similar parts in both
Figures.
A is a spur wheel with internal teeth fixed to the frame of the pulley
to prevent its revolving. B is a similar wheel, but with one or more
teeth more or less than the wheel A. The wheel B revolves on the axis
C, and is fixed to the differential pulley D with which it revolves.
Inside the internal wheels A and B is a pinion provided with external
teeth, and free to revolve upon an eccentric or pin, and gearing into the

page_text: two wheels A and B, the eccentric revolving with the axis C. Upon
one end of the axis C is a pinion E; the internal spur wheel F gears
into an intermediate pinion S; H is an ordinary hand chain pulley free
to revolve on the spindle C. In the spindle C are fitted two feathers M
and N. The slot in the eccentric and into which the feather N slides is
made sufficiently long to allow of the feather N moving laterally, but
without coming out of the slot in the eccentric. The feather M fits into
the slot in the wheel E. The action of the block is as follows:- -When
it is desired to raise a comparatively light weight, the feather M is in
the slot in the wheel E, the hand chain wheel H being free to revolve
upon the spindle C. By means of this arrangement supposing the
wheel E to be half the size of the wheel F (which last-mentioned wheel
is fastened to the chain wheel H), and the two wheels F and E being
connected by the intermediate wheel S, the spindle C revolves twice to
each revolution of the hand chain wheel H. Should the weight to be
lifted be heavy, and this extra speed not attainable, the spindle C is
then moved laterally so that the feather M is moved out of the slot in
the pinion E into the slot in the hand wheel H, leaving the pinion E to
revolve freely on the spindle C. By this arrangement the hand wheel
H moves at the same speed as the spindle C or at just one half the speed,
and consequently with double the power as when the feather M was in
the slot in the wheel E. Instead of moving the spindle C clutches may
be used, or the hand wheel H may be moved out of gear with the
intermediate wheel S, or the intermediate gearing may be dispensed
with and the hand wheel H run upon a short spindle, so that a wheel
fastened to the hand wheel H shall gear direct into the pinion E.
Two or more differential pulleys may be used with the same block.
Having thus declared and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I would
observe in conclusion, that I do not claim the several parts of the
apparatus herein-before described separate and apart from each other as
being of my Invention, neither do I limit myself to the precise details
herein set forth, as the same may be varied without departing from the
principles of my said Invention, nor do I claim the arrangements herein-
before described for obtaining increased speed; but what I consider novel
and original, and therefore claim as constituting the Invention secured
to me by the said herein-before in part recited Letters Patent is, the
combination and arrangement of a differential pulley or of differential

page_text: 66
"
pulleys in connection with the "sun and planet" or epicycloidal'
movement substantially as and for the purposes herein-before set forth
and described.
In witness whereof, I, the said Theodore Grace, have hereunto set
my hand and seal, this Twenty-sixth day of June, in the year 5
of our Lord One thousand eight hundred and seventy-two.
THEODORE GRACE. (L.S.)