Improved Means for Operating Grabs, Boxes, Buckets, or other Receptacles in Grab Cranes and similar Machines.
Year: 1892

page_text: Date of Application, 17th Nov., 1892
Complete Specification Left, 17th Aug., 1893-Accepted, 7th Oct., 1893
Improved Means for Operating Grabs, Boxes, Buckets, or other
Receptacles in Grab Cranes and similar Machines.
I, CHARLES WILLIAM MACLEAN, of 276, Walsh Street, South Yarra, near
Melbourne, in the Colony of Victoria, Engineer, do hereby declare the nature of
this invention to be as follows:-
This invention relates to grab cranes and similar machines; its object being to
dispense with the usual counterbalance weight, pitch chain, chain-pulley or drum
and brake employed in taking up the slack of the opening chain pertaining to the
grab or other receptacle.
My invention consists in certain hereinafter-described means whereby either
chains or ropes may be employed for operating the grab, while the course of the
hoisting chain or rope between the grab and the hoisting barrel (as regulated by the
guide-pulleys) may be automatically lengthened and shortened at will in order to
close or open the grab. The invention is equally applicable for hoisting or lowering
and tipping boxes, trucks, buckets or other receptacles for the conveyance of
material to be deposited either at a higher or lower level than that from which the
crane transports it.
In carrying out my invention, I employ a third pulley at the jib head of the crane
and a travelling pulley provided with two rollers, between which, on the common
axle, the travelling pulley is loosely mounted. These two rollers have inclined
paths arranged on the crane jib to allow of the required travel upward and down-
ward along the jib for the purpose of lengthening and shortening a bight or coil of
the hoisting chain or rope wound round the pulleys; such lengthening and
shortening being sufficient to close or open the grab. A pivoted catch is situated
at the lowest part of the roller-paths in order to engage with two small antifriction
rollers on the axle of the travelling pulley. These small rollers facilitate the
engaging and disengaging of the catch. A hand-lever for disengaging the catch
and a brake connected to the hand-lever for retarding the upward progress of the
two rollers and travelling pulley after their release from the said catch are also
provided.
Other devices beside the heavy rollers above described can be used for causing
the travelling pulley to shorten the hoisting rope. For instance, a hydraulic
cylinder fitted with a ram descending by its own weight and having a non-return
valve at its upper end and a convenient arrangement of counterbalanced levers and
rods for opening the valve may be employed. These rods can be used when it is
required to release the hoisting rope so as to open the grab. The lower end of the
ram has the travelling pulley above referred to secured upon it in any convenient
manner.
I prefer to carry the hoisting chain or rope round a pulley upon the two
halves of the grab and over another pulley above, and thence down to the grab, as
by that means I obtain sufficient purchase to close the grab without having to use
purchase-cams.
In order that the two grab chains or ropes may be wound evenly upon the
hoisting drum or barrel, I mount a heavy roller in slots or openings in the frame of
the crane, so that, although it is free to rise and fall to correspond with the
inequalities of the hoisting ropes or chains, it prevents them from riding over each
other. This heavy roller is provided at about its centre with a collar of

page_text: approximately the same depth as the diameter of the two chains or ropes; thus
keeping them separate from each other upon the winding drum or barrel.
Dated this 17th day of November 1892.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.
COMPLETE SPECIFICATION.
Improved Means for Operating Grabs, Boxes, Buckets, or other
Receptacles in Grab Cranes and similar Machines.
1, CHARLES WILLIAM MACLEAN, of 276, Walsh Street, South Yarra, near
Melbourne, in the Colony of Victoria, 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 grab cranes and similar machines; its object being to
dispense with the usual counterbalance weight, pitch chain, chain-pulley or drum
and brake employed in taking up the slack of the opening chain pertaining to the
grab or other receptacle.
My invention consists in certain hereinafter-described means whereby either
chains or ropes may be employed for operating the grab, while the course of the
hoisting chain or rope between the grab and the hoisting barrel (as regulated by
guide-pulleys) may be automatically lengthened and shortened at will in order to
open and close the grab. The invention is equally applicable for hoisting or
lowering and tipping boxes, trucks, buckets or other receptacles for the conveyance
of material to be deposited either at a higher or lower level than that from which
the crane transports it.
In the accompanying drawings,
Fig. 14 is a side elevation of the lower part of a crane constructed in accordance
with my invention; Fig. 1B being a fragmentary side elevation of the upper part.
, is the line of division between the two figures.
Fig. 2 is a plan corresponding with Fig. 1A; the platform being, however,
omitted.
Fig. 3 is a plan corresponding with Fig. 1B.
Fig. 4 is a cross section on the line y, y (Fig. 2).
Fig. 5 is a plan of part of the platform, showing the drums and the hand-lever
for actuating the catch mechanism and the brake.
A
I employ a third pulley A at the jib head of the crane and a travelling pulley B
provided with two rollers C, C₁, between which, on the common axle C³, the
travelling pulley B is loosely mounted. These two rollers have inclined paths
formed by rails D, D' arranged on the crane jib to allow of the required travel
upward and downward along the jib for the purpose of lengthening and shortening
bight or coil E of the hoisting chain or rope E wound round a pulley F mounted
on a shaft F, and round the pulley B. The shortening of the bight or coil allows
the loaded grab to open. The position of the pulley B when the grab is open is
shown in dotted lines in Fig. 1ª. When the grab is empty, the heavy rollers C, C'
and pulley B return into their normal position under the influence of gravity; thus
lengthening the coil E' and closing the grab. A pivoted catch H H is situated at
the lower end of the rails D, D₁ in order to engage with two small antifriction
rollers
c' on the axle C of the travelling pulley B. These small rollers facilitate
the engaging and disengaging of the catch. A hand-lever J for disengaging the
catch H H and a brake K K connected to the hand-lever for retarding the upward
progress of the two rollers C, C' and travelling pulley B after their release from
the said catch are also provided. The catch H H is keyed on a rocking shaft H'
connected by an arm H³ with a rod J' coupled to the lever J. The brake K K¹
is mounted on arms keyed to the shaft H2 and also on arms adapted to turn on the
shaft F. One of the arms keyed on the shaft H' is visible in Fig. 1ª, and.is
0,

page_text: marked H. One of the arms on the shaft F1 can be seen in Fig. 18, and is
marked F.
Other devices beside the heavy rollers above described can be used for causing
the travelling pulley to shorten the hoisting rope. For instance, a hydraulic
cylinder fitted with a ram descending by its own weight and having a non-return
valve at its upper end and a convenient arrangement of counterbalanced levers and
rods for opening the valve may be employed.. These rods can be used when it is
required to release the hoisting rope so as to open the grab. The lower end of the
ram has a travelling pulley such as that above referred to secured upon it in any
convenient manner.
I prefer to carry the hoisting chain or rope round a pulley upon the two halves
of the grab and over another pulley above, and thence down to the grab, as by
that means sufficient purchase is obtained to close the grab without the use of
purchase-cams.
In order that the two grab chains or ropes may be wound evenly upon the hoisting
drum or barrel, a heavy roller may be mounted in slots or openings in the frame of
the crane, so that, although it is free to rise and fall to correspond with the
inequalities of the hoisting ropes or chains, it prevents them from riding over each
other. This heavy roller would be provided at about its centre with a collar of
approximately the same depth as the diameter of the two chains or ropes, thus
keeping them separate from each other upon the winding drum or barrel.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, I claim :-
1. The improved means for operating grabs or other receptacles in grab cranes
and similar machines arranged or operating substantially as described with
reference to the accompanying drawings.
2. The improved means for operating grabs or other receptacles in grab cranes
and similar machines, substantially as herein described, the same comprising two
pulleys round which a bight or coil of the hoisting rope is passed, one of these
pulleys being mounted on a shaft held in its normal position by a catch, so that,
when the catch is released, one pulley can approach the other in order to shorten
the bight or coil and thus lengthen the hoisting rope to open the grab, the first or
travelling pulley receding into its normal position under the influence of gravity
when the contents of the grab have been released.
3. In means for operating grabs or other receptacles in grab cranes and similar
machines, the same comprising two pulleys round which a bight or coil of the
hoisting rope is passed, one of these pulleys being adapted when released to
approach the other so as to shorten the bight or coil and thus lengthen the hoisting
rope to open the grab and afterwards when the contents of the grab have been
released to return into its normal position under the influence of gravity in order to
lengthen the coil and thus shorten the hoisting rope and close the grab, the
employment of a brake for regulating the movements of the first or travelling
pulley, substantially as herein described.
Dated the 12th day of August 1893.
G. G. M. HARDINGHAM,
191, Fleet Street, London, E.C., Chartered Patent Agent.