Improvements in Pulley Blocks and other Lifting Machinery.
Year: 1894

page_text: Date of Application, 8th Oct., 1894-Accepted, 10th Nov., 1884
COMPLETE SPECIFICATION.
Improvements in Pulley Blocks and other Lifting Machinery.
I, WILLIAM THOMAS EADES, of 7 Claremont Road, Sparkbrook, in the City of
Birmingham, Engineer, do hereby declare the nature of this invention and in
what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
This invention relates to improvements in pulley blocks and other lifting
machinery, my object being to provide a simple and offective method of sustaining
the load on the release of the hand or other force, without increasing the
frictional or other resistance to motion during the lifting or raising operations,
and in such a manner as to enable the load to be readily lowered when required.
In order that my invention and the method of carrying the same into effect
may be the more readily understood, I append hereunto one sheet of explanatory
drawings to be hereinafter referred to.
Figure is a front elevation, partly in section, showing the application of my
invention to a pulley block having double purchase gearing.
Figure 2 is a front elevation, and Figure 3 a side elevation, representing a
like pulley block but with single purchase gearing.
Figure 4 is an enlarged view illustrating the self-sustaining action of my
improved gearing.
Referring to Figure 1, the lifting wheel A and internally toothed wheel B,
preferably cast together, are mounted loosely upon the shaft or pin C to the outer
end of which is keyed or secured the hand chain or rope wheel D. Near to the
inner end of the shaft or pin C I form or secure the two toothed pinion E suitable
for gearing into the ordinary spur or tooth wheel F. The pinion G, which is
preferably cast with the wheel F, gears into the internally toothed wheel B. The
wheel F and pinion G are mounted upon the shaft or pin H, which is fixed to the
side plate J or works in a bearing attached thereto. The extremity of the shaft C
beyond the two toothed pinion E is also supported by the side plate J. In this
manner arrange within a small compass a train of double purchase gearing,
enabling a heavy load to be raised at a moderate speed with the lifting chain
working around the chain wheel' A, by means of a small force acting at a greater
speed and applied to the hand chain or rope wheel D.
The side plates JJ' are secured together at the upper end by the crosspiece.or
hook bar K, and at the lower end by the distance piece L, as in the ordinary
manner, and the entire block with its load is suspended from a suitable support, by
the hook M.
In the single geared block as illustrated at Figures 2 and 3, the two toothed
pinion E is in like manner formed upon or secured near to the end of the hand
chain wheel spindle C, and gears into the ordinary externally toothed wheel F
preferably cast with the lifting chain wheel A. This form of block can be
employed either as a single or double lifting appliance, that is to say, the load may
be raised or lowered by the chain N on either side of the lifting chain wheel A, or
one load may be lowered during the raising of another load. A suitable hook,
shackle or other connecting piece is provided upon the ends of the chain N.
The sustaining of the load in its suspended position from the block on the
release of the lifting force is effected by the locking action of the two toothed
pinion wheel in the manner illustrated by the enlarged view Figure 4. Imme-
diately on the release of the hand or other lifting force, the suspended load tends
to run down and thus drive the wheel F in the reverse direction to the lifting
motion. If this lowering or reverse direction be represented by the arrow (), then

page_text: whatever may be the position of the teeth of the two toothed pinion E, the load
will turn the pinion in the direction indicated by the arrow O¹ until the teeth are
in the position shown at Figure 4. Further motion will then be prevented by the
contact of the point of the wheel tooth upon the extreinity e of the pinion tooth,
and the contact of the extremity of the adjacent wheel tooth upon the inner
extremity e¹ of its corresponding pinion tooth. The load will thus be effectually
sustained in its suspended position from the block. The lowering of the load is
readily effected by pulling the hand chain or rope wheel in tho. reverse direction to
that required for lifting. This will cause the pinion to turn in the direction
indicated by the arrow O¹, Figure 4, which will turn the wheel F very slightly in
"the opposite direction to that indicated by the arrow 0, sufficient to 'enable the
extremities e e¹ of the pinion teeth to pass the points of the wheel teeth. The
load will then descend freely during one half a revolution of the pinion E when
the teeth will be again brought to the locking position indicated at Figure 4. By
the continued pulling of the band chain or rope in the reverse direction to that
required for lifting the load will be steadily lowered as far as desired!
14
F
preferably form the teeth of the two toothed pinion E with a small flat
face on their inner sides in order to secure a more effectual locking or self
sustaining action.
I do not limit the application of my invention to pulley block and like appliances,
but employ it with band power and other crabs or winches, and with cranes, hoists,
and other machinery for raising and lowering heavy bodies.
Having now particularly described and ascertained the nature of any said
invention, and in what manner the same is to be performed, I declare that what
I claim is
1. In pulley blocks and other lifting machinery, the improved method of auto-
matically sustaining the load in its suspended position on the release of the lifting
force, by means of a two toothed pinion engaging with a spur or toothed wheel; in
the manner substantially as hereinbefore described:
2. The use, in pulley blocks and other lifting machinery, of a two toothed pinion
forming part of the lifting gearing, and arranged to automatically sustain the load'
in its suspended position on the release of the lifting force, substantially as
herein before described.
3. The construction of a two toothed pinion to form part of the lifting gearing
of a pulley block or other lifting machine or appliance, having a fat face on 'the
inner side of each tooth enabling the pinion to effectually sustain the load on the
release of the lifting force, substantially as herein before described and as illustrated
in the accompanying drawings.
Dated this 10th day of S104