Improvements in Pulley Blocks.
Year: 1896

page_text: Date of Application, 15th Apr., 1896
Complete Specification, Left, 15th Nov; 1896-Accepted, 9th Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in Pulley Blocks.
We, GEORGE THOMAS WINNARD, Washford Road, Engineer, and JoSEPH
BEDFORD, of Haymarket Chambers, Steel Merchant, both in the City of
Sheffield, do hereby declare the nature of our.invention to be as follows:-...
Our invention relates to the construction of pulley blocks or lifting tackle,
having for its object to enable heavy weights to be lifted with comparative ease,
and by a more convenient arrangement than hitherto.
Our invention is applicable to both single and double blocks, and although
hempen rope or chain may be used if desired, they are specially designed for the
use of steel wire rope.
For a double block, we propose that the upper block frame shall be fitted with
two winding drums supported opposite each other and provided with a continuous
Each drum is connected with a worm.
groove to receive and guide the wire rope.
wheel, the teeth of which engage with those of corresponding worms carried by a
shaft, on one end of which is the ordinary wheel and loop chain by which the
blocks are worked.
The worms are made right and left hand, and the shaft upon which they are
fixed is divided in the centre or thereabouts, the end of one part fitting into the
end of the other in such a manner as to permit a short longitudinal play while
transmitting rotary motion.
At the junction of the two parts we form a cone upon each, and between the
cones we place a correspondingly coned brake block in the form of a ratchet wheel,
a suitable pawl being carried by the block frame.
By this arrangement and the action of the right and left hand worms the brake
offers no resistance to the operation of the blocks when lifting, but comes into
action as a brake in lowering, automatically regulating its resistance to the weight
of the load.
We preferably use a single length of wire rope one end of which is secured to
one of the drums, then passed under one of the sheave pulleys of the hanging block
carried up to the fixed block, then down and under the second sheave of the
hanging block, and finally secured to the other drum. The hanging block is thus
hung centrally in a double loop of wire rope.
To guide the wire rope and keep it in the groove when the block is pulling at an
angle, we mount a thimble through which the wire rope is passed, upon a crossbar
upon which it can travel, and a part of the thimble fits into the groove of the drum
and is thereby caused to travel to and fro as the drum revolves.
In the single block there is only one drum, and the hanging block has only one
sheave, therefore there is only one loop of rope.
The perfect equilibrium and vertical action of the block is maintained by the
fall end of the rope being made movable instead of being fixed, and as the rope is
being wound upon the drum the fall end is moved in the opposite direction at the
same speed by means of a screw actuated from the worm wheel connected with the
drum and thus the loop is always kept central with the block.
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ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicants.

page_text: Improvements in Pulley Blocks.
We GEORGE THOMAS WINNARD, Washford Road, Engineer, and JOSEPH
BEDFORD, of Haymarket Chambers, Steel Merchant, both in the City of
Sheffield, 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 :-
The object of the invention is to enable heavy weights to be lifted with
comparative ease, and to retain the equilibrium of the block.
In the annexed drawings we have illustrated both a single and double sheave
block made upon our improved method, like letters of reference indicate like parts
in any of the figures.
Fig. 1, is a side elevation of a double block.
Fig. 2, front elevation of same, with chain wheel omitted.
Fig. 3, longitudinal section and end view of brake.
Fig. 4, side view of guide.
Fig. 5, two views of support for central loop.
Fig. 6, side elevation of single block, partly in section through the line X X in
Fig. 7.
Fig. 7, front elevation of single block.
These blocks are specially designed for, the use of steel wire rope, but hempen
rope or chain may be substituted if desired.
In carrying out our invention in the construction of a double block as shown in
Figs. 1 and 2, we make a frame consisting of two side plates, A, with the necessary
bolts and suspending hook B, and between the side plates we support two winding
drums C, and C2, each drum having a continuous groove to receive the coils of a
wire rope D.
Each drum is provided with a worm wheel E and E2, which may gear into each
cther or not, as preferred, and each worm wheel gears into corresponding worms F
and F2, located underneath upon a two part axle or shaft G, which also carries the
usual wheel H, and loop chain (not shown) by which the block is operated.
A second wheel and loop chain may be applied to the opposite end of the shaft G,
if desired.
One of the worms and its worm wheel is made right hand and the other left
hand, and the two part axle G, is divided between the worms, the end of one axle
being made square (by preference) and fitting into the recessed end of the other
part, in such a manner as to permit a short longitudinal movement while transmitting
rotary motion.
This arrangement is shown in Fig. 3, and as hereafter described it forms an
automatic brake which comes into action when lowering, automatically regulating
its resistance to the weight of the suspended load.
A collar I, and 12, is made upon each part of the shaft, and coned upon their
opposing sides, and between the said cones where the shaft is round is placed a
ratchet wheel J, see Fig. 3, correspondingly coned on each side and engaging with
a pawl carried by the block frame.
When the blocks are lifting, the tendency of the worm wheels is to draw the
worms and the cones together, and the pawl slips over the teeth of the ratchet
wheel as it revolves, but when lowering the ratchet wheel is held by the pawl,
automatically setting up a frictional brake action, in proportion to the weight
being lowered.
A single length of wire rope D, is secured by one end to one of the drums, it is
then passed under one of the sheave pulleys L, of the hanging block M, carried up

page_text: to the suspended block and over the loop support N, then down and under the
other sheave pulley and so up to the opposite drum to which it is secured.
It will thus be seen that the hanging block M, is always suspended centrally in
a double loop of the wire rope D.
To guide the wire ropes and keep them in the spiral grooves upon the drums
especially necessary when the block is pulling at an angle, we use a travelling
guide O, see Fig. 4, the curved edge of which fits into the groove of the drum
next to the rope; it is provided with a sliding groove which fits upon a cross-
bar P, carried between the side plates A, and also with an internally flaring
thimble Q, through which the rope D, passes and which prevents it from being
pulled out of the groove.
The central loop of the chain is carried by a loop support N, see Fig. 5, and its
position is indicated by dotted lines in Fig. 1; it is supported by the side plates A,
and is provided with a semicircular groove to receive the rope, and with guides N'.
In the single block as illustrated in Figs. 6 & 7, there is only one grooved
winding drum C, with its worm wheel E, and worm F, and the hanging block M,.
has only one sheave L.
The perfect equilibrium and vertical action of this block is maintained by the
fall end of the rope D³, being caused to travel in the opposite direction to and at-
the same speed as the rope D, as it is wound on or off the spiral groove of the
drum. To accomplish this, the end of the rope at D', is secured to a travelling-
link R, carried by a wormwheel S, resting upon a bar V. The worm gears into
the threads of the screw T, upon the end of which is a pinion U, gearing into and
driven by the worm-wheel E.
The rounded top edge of the bar V, may be also threaded, or toothed as a.
rack W, to engage with the worm S, if desired, but not of necessity.
It is to be understood that the worm-wheels E, and the pinion U, are completely
toothed, although such teeth are not shown in the drawings.
Having now particularly described and ascertained the nature of our said inven--
tion and in what manner the same is to be performed we declare that what we
claim, is:―
1. A double lifting block constructed and operating substantially as hereinbefore
described and shown.
2. A single lifting block constructed and operating substantially as hereinbefore.
described and shown.
3. In a lifting block the combination of two winding drums having worm-wheels
geared into worms upon a driving shaft, and operated by a loop chain and wheels.
substantially as described and set forth for the purpose specified.
4. In a lifting block having one or more winding drums operated by one or
more worms and worm-wheels, a worm shaft made in two parts, so connected as to-
permit longitudinal action while transmitting rotary motion, provided with a
ratchet wheel fixed loosely upon the shaft between the two parts, and so con-
structed that it is carried round by friction when the block is lifting, and held
stationary when lowering, as hereinbefore described for the purpose specified.
5. In a lifting block, a crossbar having a semicircular grooved support N, for
the centre loop of the rope of the chain, provided with one or more rope guides N',.
as hereinbefore described for the purpose specified.
6. In a lifting block having a single winding drum, a travelling link R, for
supporting one end of the rope or chain having a worm-wheel S, engaging with a
traversing screw T, and supported upon a bar, as herein before described and shown,.
for the purpose specified.
Dated the 2nd day of Narambon 1906
ROBT. F. DRURY, C.P.A.,
Bank Buildings, George Street, Sheffield, Agent for Applicants.