Improvements in Self Sustaining Machinery for Lifting and Lowering Weights.
Year: 1893

page_text: Date of Application, 24th Jan., 1893-Accepted, 4th Mar., 1893
COMPLETE SPECIFICATION.
Improvements in Self Sustaining Machinery for Lifting and
Lowering Weights.
I, EDWARD WILLIAM SANT of the Globe Elevator Works, Stockton-on-Tees
in the County of Durham, 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 self-sustaining machinery for lifting
and lowering weights the apparatus being so designed or arranged that the weight
may remain suspended at any point where the motive power ceased to be applied,
either in lifting or lowering and in the latter case by a simple lever action, the
weight can be automatically lowered without the use of applied power.
To effect these results I make use of a differential fulcrum obtained by the
adaptation of a cranked or straight shaft in combination with certain movable centres
or rocking levers, whereby the hanging weight shall so act on the shaft through
the medium of the rockers as to keep the hand or power pulley on the shaft in
contact with a suitable brake surface.
I will describe my invention with reference to the accompanying drawings in
which Figure 1 shows a side elevation and Figure 2 a sectional plan of self-
sustaining hoist or lifting machinery and in the following description like marks
of reference designate like parts.
Referring to the drawings, a is a hand chain pulley round which the chain a¹
passes. Cast on the boss of this pulley is a pinion 2. This pulley and pinion are
mounted on or towards one end of the cranked shaft 3 and the spur wheel 4 with
the lifting pulley 5 cast on it are mounted as shown on or towards the other end
of the said shaft. The ends of the cranked shaft are mounted in rocking levers 6
fitted, as shown most clearly in side view in Fig. 3, sufficiently loosely within
recesses formed in the pulley framing 7 to allow of their rocking or tilting slightly
when a weight is suspended from the lifting and lowering chain 8. The rocking
levers rock or tilt on centres coincident with lines (see Fig. 3) as fulcrums the
projections 9 formed on their under surfaces serving to prevent their grazing against
the insides of the slot in the frame. s is an adjustable segmental brake block
shown secured to the crosshead of hook. 1 is a lever mounted on shaft 3 and
having its short arm gibbed into one of the rocking levers at so that by pulling
down the long arm, the rocker can be operated by the lever or the short end of
this lever may work in a recess cast on the rocker to effect a similar result. The
machinery described is mounted in a strong frame 7 as shown.
The action of the apparatus is as follows:-
When a weight is hung on chain 8 for the purpose of being lifted by chain a' in
the usual way, the effect of the weight is to cause the rocking levers to tilt over
somewhat on their variable fulcrums which will fall approximately within the
lines as above described. Thus the end of the shaft on which the lifting or
power pulley 5 is mounted will be somewhat depressed in its frame recess and the
effect of this depression acting through the cranked shaft will be to slightly elevate
the opposite end of the shaft on which pulley a is mounted and in this manner to
push up pulley a against the brake slipper s."
The pulley a is thus forced by the suspended weight on chain 8 into contact with
the brake slipper so that the suspended weight is self-sustaining as regards any
position in which it may be hanging.
To lower the weight, by simply depressing the long arm of lever 1, the end of the
rocker 6, where the short end of the lever is secured or fitted to or in it, is raised,
the opposite end of this rocker being of course depressed in its recess, precisely as

page_text: described with reference to the rocker on the other end of the shaft. By this
action of the lever and rocker, the pulley a is depressed sufficiently to keep it clear
of the brake slipper, when the suspended weight can descend without the necessity
for applied power.
Instead of a crankshaft, I may obviously use a straight shaft arranged with
rockers as described. The action is the same in both cases, but the cranked shaft
of course gives a greater purchase.
Instead of the rockers as shown, other forms of variable centering might
obviously be employed, such as eccentrics or discs.
The gearing shown by spur 4 and pinion 2 need not necessarily be employed:
direct acting machinery acts in the same way as regards the automatic self-
sustaining gear above described.
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 :
1. The combination or arrangement of parts constituting improved self-sustaining
machinery for lifting and lowering weights consisting in the provision in combination
with the shaft whether cranked or straight of rocking bearings or levers adapted to
vary the shaft centerings for the purpose of causing the weight to keep the brake
or hand wheel in gear with the brake segment block substantially as herein set
forth.
2. In self-sustaining machinery for lifting and lowering weights, the combination
with a shaft whether cranked or straight of rocking bearings or levers adapted to
vary their centres and to be operated by a hand lever for the purpose of lowering
the weight the several parts being arranged with respect to one another substantially
as herein set forth.
Dated this 10th 1 of T 1002
A. CRAWHALL CHAPMAN,
3, St. Nicholas Buildings, Newcastle-on-Tyne, Patent Agent.