IMPROVE- MENTS IN LIFTING MACHINES AND APPLIANCES FOR RAISING WEIGHTS
Year: 1884

page_text: GEORGE CROYDON MARKS 8 Richmond Road Handsworth Staffordshire
Mechanical Engineer, do hereby declare the nature of my invention for IMPROVE-
MENTS IN LIFTING MACHINES AND APPLIANCES FOR RAISING WEIGHTS, to be as
follows:-
My Invention for improvements in lifting machines and appliances for raising
weights refers principally to the manner in which I cause the load or weight to be
automatically sustained in any position when the lifting or motive power is
removed. I attach or apply to the machine for raising weights a brake so arranged
that it shall not be brought into action when the load is being lifted, but only
come into action as a retarding or opposing force when the weight or body tends to
descend. Thus in one part of my invention I employ one or more friction wheels
or discs keyed on to a spindle or spindles of the machine, but the hole upon which
such spindle or spindle is keyed not being concentric with the periphery of the:
wheels or discs. This friction wheel or wheels I cause to come in contact with a
second wheel or wheels attached to or secured to the shaft upon which I prefer to
have keyed the pulley for raising the weight. The friction wheels will not be in.
contact one with the other at one point, on account of the eccentricity of the hole
with the periphery, and the position when only just in contact I prefer when the
load is to be lifted. But when the load is to be sustained the position will be that
brought about by the eccentric wheel being moved into very close contact by
reason of the contrary motion of the driving friction wheel. The motion being
derived from the machine itself to apply this brake and not by any levers etc.
I also employ a lever or system of levers with a hand cord attached to same to
remove the eccentric wheel from contact with the driving friction wheel, when it is
desired to allow the weight to descend by gravity alone.
Another part of my invention relates to the arrangement of wheels for friction
as before described, working in conjunction with a lever or system of levers to
apply a band or ordinary brake upon some other part of the machine. This being
accomplished preferably by attaching to the eccentric wheel or wheels a connecting.
link secured at its other end to the lever anchored to the brake strap in such
a manner that when the eccentric wheel is deeply in contact with the driving
friction wheel, the lever is acted upon and the brake applied.
In this case also I remove the wheel from contact and thus release the brake by
the before described lever and cords.

page_text: Improvements in Lifting Machines and Appliances for Raising
Weights.
GEORGE CROYDON MARKS 8 Richmond Road Haudsworth, Staffordshire
Mechanical Engineer do hereby declare the nature of my invention for IMPROVE-
MENTS IN LIFTING MACHINES AND APPLIANCES FOR RAISING WEIGHTS and in what
manner the same is to be performed, to be particularly described and ascertained in
and by the following statement :-
My invention of improvements in Lifting Machines and appliances for raising
weights, refers principally to the manner in which I cause the load or weight to be
automatically sustained in any position when the lifting or motive power is
removed. I attach or apply to the machine for raising weights, a brake so arranged
that it shall not be brought into action when the load is being lifted, but only
come into action as a retarding or opposing force when the weight or body tends
to descend.
Thus in one part of my invention I employ one or more friction wheels or discs
keyed on to a spindle or spindles of the machine; but the hole upon which such
spindle or spindles is keyed not being concentric with the periphery of the wheels
or discs. This friction wheel or wheels I cause to come in contact with a second
wheel or wheels attached to or secured to the shaft upon which I prefer to have
keyed the pulley for raising the weight. The friction wheels will not be in contact
one with the other at one point on account of the eccentricity of the hole with the
periphery and the position when only just in contact I prefer when the load is to
be lifted. But when the load is to be sustained, the position will be that brought
about by the eccentric wheel being moved into very close contact, by reason of the
contrary notion of the driving friction wheel. The motion being derived from
the machine itself to apply this brake, and not by any levers etc. I also employ a
lever or system of levers, with a hand cord attached to same, to remove the
eccentric wheel from contact with the driving friction wheel, when it is desired to
allow the weight to descend by gravity alone.
;
Another part of my invention relates to the arrangement of wheels for friction
as before described, working in conjunction with a lever or system of levers to
apply a band or ordinary brake upon some other part of the machine. This being
accomplished preferably by attaching to the eccentric wheel or wheels a connecting
link secured at its other end to the lever anchored to the brake strap, in such a
manner that when the eccentric wheel is deeply in contact with the driving
friction wheel, the lever is acted upon and the brake applied. In this case also I
remove the wheel from contact and thus release the brake by the before described
lever and cord.
Figure 1 of the accompanying Drawing represents in side elevation, and Figure 2
in end elevation a portion of a hoist to which my improvements are applied.
Figures 3 and 4 represent respectively in side elevation and plan, the brake or self
sustaining parts of a larger hoist or lifting machine, detached The same letters of
reference indicate the same parts in Figures 1. 2. 3 and 4.

page_text: a is the hand rope wheel on the shaft e, and b is the lifting chain or rope wheel-
keyed on to the same shaft, the said shaft c has also upon it the brake or friction.
wheel c.
The periphery of the wheel c is in contact with the friction wheel d, the
said friction wheel is carried by a shaft f, the same being either secured to the
shaft or running freely upon the same. The said wheel dis bored out to suit
the cylindrical shaft f, but the hole. is not concentric with the periphery; the
wheel dis balanced and controlled by levers g and h, the lever h being arranged
for cord to be attached to the same, in order that the eccentric wheel d may be.
caused to turn upon the shaft f. The eccentric friction wheel & has a projecting
lug standing out from the side of same, and arranged to come against the side™
frame. In some cases I prefer to employ an adjustable stop for the lug to rest
upon as shown in Figure 3, 4, 5, and 6, or I cause the lug itself to be adjustable
by means of nuts N in Fig. 5 and Fig. 6. The action of the parts of lifting
inachines hoists &c is as follows. On turning the hand rope wheel a in the
direction proper for lifting the load or weight, suspended from the rope or chain-
wheel b, the friction wheel c on the same shaft is also rotated. On liberating the
rope of the hand rope wheel a so as to arrest the lifting motion of the load; the
eccentric friction wheel & bearing upon the surface of the wheel c, by reason of the
weight at end of the lever g, is caused to move by the movement of the friction
wheel c now acted upon by the suspended load. But the movement of the eccentric
wheel d is in effect the movement of a very gradually increasing wedge which is
caused to come into the fixed space between the centres of the shafts é and f, and
thus to exert a pressure upon the surface of the concentric friction wheel c.
the eccentric wheel turns the pressure increases, and there is a tendency to force
apart the two shafts e and f; and to prevent this I prefer to employ the adjustable
stops or the adjustable lug as shown in Fig. 3, Fig. 4, 5 and 6; this arrangement_I
also adopt for taking up the wear upon the surface of the friction wheels-In
order to lower the load or suspended body, it is necessary to depress the lever h,.
by pulling the cord j attached to same, until the surface of the friction wheels are
brought out of contact one with the other; the load will now cause the wheel b to
rotate rapidly, and the weight or load will descend by gravity alone. This descent
may be checked by allowing the brake cord to go slack and thus bring the
eccentric wheel into contact with the friction wheel, and by letting the rope go
free the descent will be arrested and the weight brought to a stand still. Figure 5
represents in side elevation and Figure 6 in plan an arrangement by which I apply
an ordinary brake by means of the friction wheels as before described. In this
part of my invention I prefer to employ a differential brake lever p working upon
a fulcrum r for the purpose of tightening the brake strap circumscribing the
brake o.
As
Thus with the eccentric friction wheel d as before described working in contact
with the friction wheel c, the pressure brought about by the eccentricity is not the
only retarding force when the load is suspended, seeing that I make the adjustable
lug to bear upon the brake lever and thus apply the brake. By this arrangement
the checking or self sustaining force is distributed over two surfaces. Figures 7
and Fig. 8, represent in side elevation and in plan an arrangement of my invention
which I prefer to adopt for careful lifting and lowering purposes.
The projecting lug I employ to put on an ordinary brake as in Figure 6, but
the brake lever I prefer to prolong in order that the end of the cord fastened to
the eccentric wheel lever h may be brought up and fastened to the end of p. By
this plan I control more effectually the speed with which the load can descend
when the friction wheel is out of contact with the eccentric friction wheel.
Figure 9 and Figure 10 represents in side elevation and in part sectional
elevation an arrangement of my invention applied to a pulley block.
I employ a hand rope or chain wheel a working upon a spindle having the end
of same formed into a toothed pinion 8, this said pinion a gears into an internal
tooth wheel c having cast upon its central boss a chain wheel b from which chain
is led to a bottom sheaved block. The outer surface of the internal toothed wheel c.

page_text: forms the friction surface to work in connection with the eccentric friction wheel d
as shown.
I also employ levers and adjustable stop for lug as before described.
The application of my invention to other systems of lifting machines and
appliances for raising weights, differs in no essential respects from its applications
as herein before explained and described.
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
1st The application of the eccentric friction brake to oppose the descent of the
body or weight that is to be lifted, by working in conjunction with another
friction, rotating surface; to machines and appliances for raising weights, sub-
stantially in the several ways herein before described and illustrated in the
accompanying Drawing.
2nd The application of the eccentric brake to work another ordinary brake, 1
upon machines and appliances for raising weights substantially as described and
illustrated in the accompanying Drawing.
3rd The application of the eccentric brakes working in conjunction with other
moveable parts of machines &c, and provided with adjustable stops and projections
for regulating the pressure to be applied by the same, substantially as hereinbefore.
described and illustrated in the accompanying Drawing.
Deted this Fifteenth day of September 1885.