Improvements in Pulley Blocks, and other like Lifting Tackle.
Year: 1898

page_text: Date of Application, 6th May, 1898--Accepted, 13th Aug.,
1898
COMPLETE SPECIFICATION.
Improvements in Pulley Blocks, and other like Lifting Tackle.
I, WILLIAM LOCKWOOD, of Princess Works, Matilda Street, in the City of
Sheffield, Engineer, do hereby declare the nature of this invention and in what
manner the same has to be performed, to be particularly described and ascertained
in and by the following statement:-
My invention relates to improvements in the construction of chain pulley
blocks, and other like lifting tackle, and as applied to such pulley blocks is
illustrated in the annexed sheet of drawings, in which
Fig. 1, is a side elevation of a chain pulley block,
Fig. 2, is a front elevation of same.
In carrying out my invention as shown in the drawing, I use an endless loop
of chain A, which is passed round the grooves of a double pulley B, having a
central part C, constructed as a worm wheel.
Each groove of the double pulley is provided with recesses or pockets to receive
the links of the chain, and prevent it slipping.
These three integral parts which compose the double pulley and the worm
wheel, may be cast together in one piece, or they may be made separately and be
secured together, as preferred.
One side of the pulley is made rather larger than the other in its diameter, and
has one recess or link pocket more than the other side.
A worm D, gearing with the worm wheel C, is carried by the frame E, which
is arched over the worm to protect it from dirt, and is provided with a suspending
hook F.
The projecting end of the worm shaft carries a wheel G, and a hand chain H,
by which a rotary motion is imparted to the worm D, and transmitted to the
chain pulley B..
The thrust of the worm shaft is borne by a hardened centre or bush I, and I
prefer to carry the opposite end upon roller bearings indicated at J.
In some cases I dispense with the central part C, and form the worm wheel,
or a circle of worm teeth, round the periphery of one of the pulley sides, leaving
sufficient room underneath the worm for the lifting chain to pass freely.
In one of the loops of the lifting chain A, I place a snatch block K, with a
lifting hook and chain guides.
When the worm is rotated in one direction, the larger pulley takes up one link
more than the other at each revolution, and thus raises the block K, with the
weight; when it is rotated in the opposite direction the speed is increased for
lowering.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
:―
1-A pulley block or similar lifting appliance having a combined double chain
pulley of two diameters each provided with chain recesses or pockets, one pulley

page_text: having one recess more than the other, and in combination with a worm wheel
and worm substantially as herein before described and shown.
2 In a lifting block or like lifting tackle, a double chain pulley with a central
worm wheel combined therewith, one of the pulleys having more chain recesses
than the other; in combination with a driving worm situated above the wheel, as
hereinbefore described and shown.
OF 11
11000
ROBT. F. DRURY, C.P.A.,
Agent for Applicant, Bank Buildings, George Street, Sheffield.