Improvements in Apparatus for Raising and Lowering Weights.
Year: 1894

page_text: Date of Application, 23rd Aug., 1894
Complete Specification Left, 22nd May, 1895-Accepted, 6th July, 1895
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Raising and Lowering Weights.
I, HENRY CLARK, of the Teesdale Iron Works, Thornaby-on-Tees, in the
County of York, Draughtsman, do hereby declare the nature of this invention to
be as follows:-
This invention relates to apparatus for raising and lowering weights and has
especial reference to such apparatus when constructed in the form of pulley blocks
operated on the differential principle, the object in view being to reduce the cost
of the construction of such apparatus mainly by simplifying and reducing the
number of parts, such as by substituting a stationary axis to carry the rotating
parts instead of the axis itself rotating, by which accurately finished bearings are
dispensed with in the side cheeks, and by dispensing with internal gearing and
with it the consequent necessity for internal lubrication.
The essential features of my invention consist as follows: The burden chain
sprocket wheels are cast in one piece with a hand chain wheel so that instead of
one burden chain wheel being used to operate the other, both are operated by the
hand chain wheel; this arrangement enables the burden wheels to be so reduced
in diameter as to materially reduce the speed or travel of the burden chains, and
thus the apparatus becomes a handier lifting appliance with less wear and tear and
loss of power in friction than when the larger burden wheels are used to operate
one another. But as this combination of parts which embodies my invention in
its simplest form is not conveniently applicable for raising heavy weights, mainly
on account of the increase of diameter required in the hand chain wheel, I mount
the hand chain wheel in some cases on a separate axis, and gear the burden wheels
to it by means of a spur wheel and pinion preferably furnished with helical teeth,
and in this way obtain the required mechanical advantage without resorting to the
use of a hand wheel of an inconveniently large diameter. In some instances the
burden wheels are cast in a piece with the spur wheel, the differential principle
being applied through the burden wheels themselves, but in other cases the spur
wheel is divided into halves, the plane of division being at right angles to the
axis and the two halves are differentially geared so that the burden. wheels which
in this case may be equal and similar are rotated in opposite directions or at
different speeds.
Dated this 92nd der of Angust 1901
COMPLETE SPECIFICATION.
Improvements in Apparatus for Raising and Lowering Weights.
I, HENRY CLARK, of the Teesdale Iron Works, Thornaby-on-Tees, in the
County of York, Draughtsman, do hereby declare the nature of this invention
and in what manner the same is to be performed, to be particularly described and
Fascertained in and by the following statement :-
This invention relates to apparatus for raising and lowering weights and has
CD 025

page_text: especial reference to such apparatus when constructed in the form of pulley blocks
operated on the differential principle, the object in view being to reduce the cost
of construction of such apparatus mainly by simplifying and reducing the number
of parts such as by substituting a stationary axis to carry the rotating parts where
a rotating axis has hitherto been used and by which accurately finished bearings
in the side cheeks and elsewhere of the block are dispensed with and furthermore
by substituting external for internal gearing I avoid a complicated interlocking
of parts thus enabling the block to be readily fitted together and taken to pieces
and if preferred enclosed in a frame cast in one piece.
One of the advantages incident to the use of external gearing is that burden
wheels can be made large enough in diameter to be operated by their own chains
when dealing with light weights without unduly increasing the dimensions of the
other parts of the pulley block to accommodate them.
But in order that the essential features of my invention may be clearly
ascertained and readily carried into effect I will now proceed to describe the
same with reference to the accompanying drawing in which
บ
Figure 1 is a sectional view of a pulley block constructed according to my
invention and taken on line xx of Figure 2, which is a sectional view taken on
line y.y of Figure 1; and
Figure 3 illustrates to a smaller scale my improved pulley block fitted up in
readiness for use.
In the figures, a is the hand chain or operating wheel mounted on the spindle b
as its axis and having attached thereto the pinion c either in one casting as shown
or otherwise, which pinion gears externally into the spur wheel & secured to and
shown as forming one casting with the burden chain sprocket wheels el e³ mounted
on the spindle as their axis. As the hand chain wheel a with the pinión c
attached thereto is free to rotate as one body on the spindle b, and the burden
chain sprocket wheels e¹ e with the spur wheel d are similarly free to rotate as
one body on the spindle f, it is obvious that the moving parts of the block can be
operated without rotating either of the said spindles 6 and which accordingly
extend as fixtures from side to side of the pulley block frame in the manner shown
more particularly in Figure 1 where the boss or nave of the hand wheel a may
extend across the frame of the apparatus. Bosses or enlargements g' 9³ of the
form shown in Figure 1 are preferably provided as retaining guides to the burden
chains whereby the said burden chains are restrained from jumping out of
their places and in some cases the cross bar k of the frame is brought close to
the rim of the hand chain wheel a to similarly retain the hand chain in the groove
thereof.
STP
It will also be observed that by gearing the pinion c and spur wheel d externally
instead of internally the spindle 6 can not only be a fixture extending
nding across from
side to side of the frame but that the two spindles b and fare, or can be set
further apart and so afford accomodation for an increase in the diameter of the
burden wheels ¹e to the extent required to enable them to be operated direct
from the burden chain when dealing with light weights.
The object of my invention is achieved by the above described arrangement of
parts, which nevertheless can be modified to a certain extent, so long as the moving
parts rotate independently of the spindles and do not interlock so as to complicate
the fitting up and taking of them to pieces that is to say that the burden chain
sprocket wheels ele can be placed together instead of having the spur wheel d
between them, the tubular extension from, the hand or chain wheel being modified
to correspond thereto. But in so far as the invention described in my Provisional
Specification relates to the simpler form of construction of parts as adapted for light
weights only in which burden chain sprocket wheels are cast in a piece with a hand
chain wheel as an improvement on the construction of parts in which one burden
wheel is used to operate the other, or the said invention relates to the construction
of parts in which a spur wheel is divided into halves differentially geared with
each half driving a burden wheel attached thereto; I have since found that in the

page_text: former case there is reason to doubt the novelty of the precise arrangement of
parts described, and in the latter arrangement the results in practice are not
satisfactory, and I therefore discard the two modifications in question and confine
my invention to the arrangement and construction of parts by which a chain or
hand wheel mounted on one axis operates burden wheels mounted on another axis
geared together to lift heavy weights or if required I adapt my improved pulley
block for dealing with lighter weights as well by providing burden wheels of
suitable diameter to be operated direct from the burden chains; and in conclusion
I would remark that I do not attach special importance to the use of helical teeth
as suggested in my Provisional Specification.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
A pulley block for raising and lowering weights in which the hand or operating
wheel mounted on a spindle has a pinion attached thereto and gearing externally
into a spur wheel mounted on another spindle, and having the lifting or burden
and for the purposes
wheels attached thereto, constructed and combined as
specified, substantially as hereinbefore described with reference to the accompanying
drawing.
1002
G. J. CLARKSON,
Chartered Patent Agent, Stockton-on-Tees,
Agent for the Applicant.
G. J. CLARKSON,
Chartered Patent Agent, Stockton-on-Tees,
Agent for the Applicant.