Year: 1886

page_text: I, WILLIAM ROBERT GREEN of the Newington Iron Works Falmouth Rd. S.E.
Engineer, do hereby declare the nature of my said invention to be as follows:-
My Invention relates to improvements in that class of lifts hoists and like
apparatus called self-sustaining in which the load is automatically held when the
operating force is withdrawn. The special object of my invention is to overcome.
the drawback of the self-sustaining hoists generally used in which the load descends
by jerks and cannot be steadily lowered without very great care.
In the manner in which preferably construct my apparatus the shaft which
operates the lifting or hauling drum or corresponding mechanism has keyed on to
it a crosshead having two cama. These cams may be of any suitable shape for the
purpose of holding the load when the hauling rope or driving wheel is released one
operating when the load tends to revolve the shaft in one direction and the other
in the other direction. These cams act against a break sheave and are each
operated by a lever and rubbing piece which also bears against the break sheave.
This break sheave is prevented from rotating by a break and loaded lever and is
mounted loosely on a sleeve which runs freely on the shaft but is connected to the
driving wheel. The driving wheel is not keyed tightly to the shaft but attached
in such a manner that it can move a little way independantly of the shaft and is
provided with projections which engage with the cam levers.
The mode of operation of a hoist constructed after this principle is as follows.
When the load is being lifted the projection on driving wheel keeps free the cam
that would otherwise act and the driving wheel operates the shaft direct. The
rubbing piece on the lever of the other cam causes it to be moved clear of the
break sheave and kept there. On releasing the driving wheel the load revolves
the shaft a little in the reverse direction carrying with it the driving wheel and
crosshead. The break sheave is held stationary by the break and loaded lever so
that the rubbing piece causes the cam to be pressed against the break sheave and
by the friction thereby set up stops further motion of the shaft. The pressure of
the cam on the break sheave also causes the latter to press on the sleeve connected
to the driving wheel so that this is checked at the same time that the load is,
checked. This friction is however less than the friction of the cams allowing the
driving wheel to be moved independantly in either direction as far as its freedom
of connection with the shaft will allow. For a little way it is under the influence
[ Price S17

page_text: of this break but when it has moved far enough in either direction to release the
cams it is itself released entirely. When the pressure on cams is released the shaft
again can revolve in the same direction as the driving wheel. Should, however,
the load gain on the driving wheel the rubbing piece again presses the cam against
the break sheave thus checking the load until the driving wheel overtakes it. The
cams and break act so quickly that the checking and releasing of the load are
almost imperceptible when the driving wheel is kept revolving. The load may
also be lowered as in an ordinary hoist by releasing the break lever so that the
break sheave crosshead etc all can revolve together.
It is obvious that when the load acts always in one direction only one cam is
necessary and that the apparatus in its simple or compound form is equally
applicable to hauling, hoisting, and like machinery whether operated by ropes
chains or any other medium. The cams also may be duplicated to any extent.
Improvements in Lifts and Hoists and the like.
I, WILLIAM ROBERT GREEN of Newington Iron Works Falmouth Road
London S.E. Engineer, do hereby declare. the nature of my said invention
and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement, reference being had to the
accompanying drawings:-
My Invention relates to improvements in that class of lifts, hoists and like
apparatus called selfsustaining in which the load is automatically held when the
operating force is withdrawn.
The special object of my invention is to overcome the drawback of the self-
sustaining hoists generally used in which the load descends by jerks and cannot
be steadily lowered without very great care.
In the accompanying drawings the same letters indicate the same parts and the
different figures shew different views of the same arrangement of hoist. I have
selected this arrangement for description and illustration as being a simple one,
although my invention is equally applicable to all forms of lifting, hoisting and like
machinery.
Fig. 1 is a general view of the complete hoist. Figs. 2. 3. 4 & 5. are different
views of the selfsustaining gear. Fig. 2 is a plan view half sectional. Fig. 3 is a
cross sectional elevation along line xx, fig. 2. Fig. 4 is a longitudinal sectional
elevation of part of fig. 2 along line y. y. Fig. 5 is a cross sectional elevation
along line 3. z. fig. 2.

page_text: A is the hauling or driving wheel with boss a. This boss has projections.a¹ a
for operating cams F F¹ and a³ for engaging with sleeve B. It is provided with a
key way a³ formed wider than the key c so as to allow the wheel. to be moved a
little without operating the shaft. In the hoist here illustrated the driving wheel
is shewn with a plain groove to receive the rope as a³ although it might have
projections to suit a chain or be replaced by a crank hand wheel, toothed wheel or
any convenient mechanism for transmitting power. It might have two or more
keyways in place of the one, or instead of the key and keyways some other
arrangement such as a pin through the shaft which would allow of the same
action.
B is a sleeve mounted loosely on the shaft C and having horns b which engage
with the projections a² on boss of driving wheel A.
C is the shaft connecting. the driving and sustaining gear with the lifting
sheave E. It has a key c.for securing crosshead D and receiving motion from
driving wheel A. The shaft runs loose in bearings c¹ and has collars c³ to keep it
in its place.
D is the crosshead keyed tightly to shaft C. It carries at its outer ends the
cams F, F, and has holes d, d¹ large enough to allow rubbing pieces ƒ³ f' a
definate movement.
E is the lifting sheave in this case shewn with a plain groove to receive the
lifting ropo e, e¹ and keyed to the shaft C. although it might have projections to
suit a chain or be replaced by a drum or other suitable contrivance and might also
be placed on another shaft driven by shaft C by appropriate gearing, chains, etc.
F, F, are the grooved eccentric cams secured to spindles f which are carried by
crosshead D and operated by levers f¹f' having rubbing pieces f³ f* kept against
break sheaf G by springs f5. The cams are here shewn circular and eccentrically
mounted. They are easily constructed in this form but may be of any convenient
shape that will answer the same purpose. The cam F will act when the load is
suspended on rope e, and the cam F' when on rope e'. In single hoists where the
load is lifted always at the same side of sheave or barrel etc; only one cam is
necessary. These cams or cam may however be duplicated when required.
G is the break sheave mounted loosely on sleeve B and prevented from rotating
by break strap H. It is grooved at g to suit cams F, F¹.
H, is the break strap operated by lugs h on break lever h¹ which has a weight h³
for keeping the break on under ordinary conditions. This break is for the purpose
of independant lowering so that when taken off by means of the cord h³ the cross-
head driving wheel, break sheave etc; all revolve together and the load may thus
be lowered readily and quickly. When however it is not necessary or advisable
to lower the load except by means of the driving wheel the break gear may be
dispensed with and the break sheave prevented from rotating by being connected
to the shaft bearing or in some other suitable manner. It is also evident that any
other form of breaking or arresting mechanism may be substituted for the one
illustrated and described.
The mode of operation is as follows supposing the load to be on rope e. The
load if lifted by pulling on rope a this causes the shaft to revolve in the direction
of arrow on fig. 3: The projection a on driving wheel A keeps free the cam F
which would otherwise act and the driving wheel operates shaft through key c,
the rubbing piece f³ on lever f¹ of other cam F causes it to be moved clear of
break sheave as far as groove will allow and keep it there. On releasing rope a³
the load acting on rope e revolves the shaft a little in the reverse direction carrying
with it the driving wheel A and crosshead D. The break sheave G is however held
stationary by the weight h² so that the rubbing piece f³ causes the cam F to be
pressed against break sheave and by the friction thereby set up stops further
motion of the shaft C. The pressure of the cam F on the break sheave also causes
the latter to press on the sheave connected to the driving wheel so that the latter
is checked at the same time. This friction is however less than the friction of the
cams allowing the driving wheel to be moved independantly in either direction as
•

page_text: far as its freedom of connection with the shaft will allow. When the load is to be
lowered the hand wheel is moved in the reverse direction to the arrow.
For &
little way it is under the influence of the break but when it has moved far enough
to cause the projection a¹ to release the cam F. it is itself released and can run
freely. When the pressure on cam is released the shaft again revolves under the
influence of the load. Should however the load gain on the driving wheel the
rubbing piece again presses the cam F against the break sheave thus checking
the load until the driving wheel overtakes it. When the load is on e¹ the cam F¹
holds the load and the above operations are performed in like manner by turning
the driving wheel in the reverse direction in each case.
.
The load may also be lowered as in an ordinary hoist by lifting the break lever
so that the cross head, driving wheel break sheave etc, all revolve together.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed I wish it to be
particularly understood that I do not bind myself to the exact details herein
described and illustrated but I do declare that what I claim is,
1. The general construction of single or double acting selfsustaining gear
substantially as shewn and described, as far as regards the manner of operating
the same with rubbing pieces and projections or corresponding means connected
with or forming part of the driving wheel or corresponding mechanism.
2. A secondary break arrangement for arresting the driving wheel or corre-
sponding mechanism by the same movement that operates the break for arresting
the load.
3. The form of selfsustaining gear complete with sleeve, break, break cams,
rubbing pieces etc, arranged substantially as shewn and described.
Dated this 14th day of Tuli 1000
WILLM ROBT GREEN.