IMPROVEMENTS IN SELF-ACTING GRABS, AND IN THE CRANES OR APPARATUS FOR WORKING SAME
Year: 1882

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for an Invention of "IMPROVEMENTS IN
SELF-ACTING GRABS, AND IN THE CRANES OR APPARATUS FOR WORKING
SAME."
A communication from abroad by Charles William Maclean, of
the City of Melbourne, in the Colony of Victoria, Engineer.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 19th January 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN SELF-ACTING GRABS AND IN THE CRANES OR
APPARATUS FOR WORKING SAME." A communication from abroad by Charles
William Maclean of the City of Melbourne in the Colony of Victoria, Engineer.
The said Improvements in grabs relate to the contrivances through which the
grappling portion receives its necessary motions of opening closing hoisting and
lowering; and the said improvements in the contrivances used for working same
consist first in the substitution of a counterbalance barrel supported on pinions
running in racks at the back of the crane, for the ordinary counterbalance weight
and in so arranging such counterbalance barrel that it assists, instead of retards,
the engine in all the operations of working the grabs; and second in a modified
construction of crane for working the grabs, in which it is made a portable
machine.
The grab has pivotted jaws with half buckets or forks attached. Four links
connect the jaws with a rotating shaft capable of travelling vertically in guides in
the framing of the grab which carries a main pulley and two smaller warping
pulleys provided with stops and having warping chains each secured at one end to
their respective pulleys and at the other end to the fixed jaw pivots. The grab is
fitted with a frame for keeping the centres in position and with guide pulleys.
The hoisting chains are secured to the beforementioned main pulley and led to the
crane round the jib pulleys to the hoisting pulleys which are secured to a shaft
supplied with a driving wheel and brake. The engine shaft has a loose spur

page_text: pinion gearing into the driving wheel and is driven at will by a friction cone
clutch. The ends of the hoisting chain are led over pulleys to the counterbalance
barrels which are secured to a shaft provided with pinions gearing into inclined
racks at the hinder part of the crane. The said pinions and the racks are shrouded
to the pitch line to form a rolling surface and guides keep the pinions into gear.
The opening and lowering chain is secured to the main pulley of the grab and
wound round it in a contrary direction to the hoisting chains thence led to crane
round pulley to chain pulley or barrel which runs free on the shaft a barrel on the
hoisting pulley shaft is supplied and fitted with a carrier with a pin projecting
into a friction driving wheel running free on a loose eccentric on the said shaft.
This eccentric is actuated by a handle by which the said friction wheel can be
pressed against the friction driving pinion or against the brake thus driving or
stopping the opening and lowering chain pulley. The said friction driving pinion
is secured to the engine shaft. The table of the crane is provided with a roller
path upon which turns the upper part of the crane and the water tank supporting
the boiler the whole being supported by a Smeaton's ring of rollers kept in position
by a centre wrought iron pin (which is bored out to allow the boiler feed pipe to
pass down below the carriage) and rolling on the lower roller path which is on a
fixed spur wheel secured to the sole plate which sole plate is provided with bearings
wheels and axles as required. Traversing is performed by the gearing provided
for the purpose and easily accessible for repairs.
The various operations of closing and digging hoisting opening lowering and
counterbalancing the grab jaws are effected in a novel and improved manner by
the mechanical contrivances herein described as follows:-
Assuming that the grab is resting in the open position on the material to be
lifted; the grab is then closed by putting the chain hoisting pulleys into gear
with the engines when in motion in the proper direction, thus pulling the hoisting
chains which being wound round the main pulley causes the warping pulleys of the
grab to revolve drag down the shaft (carrying the pulleys of the grab) by the
warping chains winding round their respective pulleys and closes the jaws of the
grab with their attached balf buckets or forks. During the operation of digging
above described, the counterbalance barrels take in the slack of the two hoisting
chains and assist instead of retard as in other machines, the engine while performing
the operation of digging. The opening chain being left free, winds round the main
pulley of the grab and thus gets ready for the opening process during the operation
of digging. The pulling of the hoisting chains being continued after the jaws are
closed, the grab with its load is raised the counterbalance barrel still taking in the
slack of the hoisting chains and assisting the operations of hoisting. When the
grab has attained the required height the foot brake is applied to stop the chain
or hoisting pulleys and the engine is thrown out of gear by the mechanical con-
trivances provided for the purpose. The eccentric handle is next used to put the
opening chain pulley into gear with the engine to pull the opening chain which
being wound round the main pulley of the grab causes it to revolve until stopped
by the stops thus unwinding the warping chains of the gear from their respective
pulleys and dragging up and opening the jaws of the grab with their attached
half buckets or forks. When the grab is open the eccentric handle is used to brake
the opening pulley by the gearing herein described and the grab remains suspended
half by the opening chain and half by the hoisting chains and as the latter chains
are always acted on by the counterbalance barrels with a force equal to half the
weight of the grab the foot brake can now be left free and the grab will remain
open, ready to be lowered by the opening chain checked by the eccentric handle.
While the grab is being lowered the counterbalance barrels let out sufficient hoisting
chain from their circumferences to allow the grab to fall to any required depth,
and at the same time roll up the shrouding of the before mentioned inclined racks
ready for rolling down when the grab is again raised, wrapping the hoisting
chains again on their circumferences and acting as a counterbalance to the grab
and crane.

page_text: The weight of the eccentric handle acting sufficiently on the friction wheels
when the load is being raised takes in the slack opening chain along with and at
the same speed as the hoisting chains.
It will be observed that unlike other machines for effecting a similar purpose
the digging in any material of the jaws of the grab is not interfered with by the
counterbalance, which assists instead of retards the engine in performing this
operation while the whole weight of the grab bears on the points entering the
material to be lifted. In other machines the counterbalance acts on the opening
chain, and therefore counteracts the process of closing the grab and digging the
material to be lifted. In other machines the grab cannot be raised open, but in
the machine herein described the grab jaws can be opened by the opening chain
when the grab is in any position whatever and the grab can be raised while open
to any required height, which is often useful in dredging operations where the
grab is frequently closed by accident or immovable objects below water, in which
case other machines are troublesome to open. Again in other machines when
opening the grab the load is suddenly transferred from the hoisting chain to the
opening chain, which is a severe strain on the chains and other parts of the crane
causing frequent breakages.
It will be seen that in the machine herein described the load is discharged while
all the chains are taking part of the strain and there is no sudden or great strain
at any time on either of them.
In order to make the crane in a portable form the boiler engine and counter-
balance may be left out and the various operations of digging hoisting. opening
traversing and lowering the grab without these may be performed by a modified
form of crane. In this modification arrangement is made for driving by a belt
from either the fly wheel of a separate portable engine or other motive power
working a pulley keyed to a horizontal shaft which by bevel wheels drives a
vertical shaft passing up through the centre pin of the turn table and driving by
bevel wheels the barrel shaft which has a friction disc keyed to it. The hoisting
chain pulley and the opening chain pulley (each with special friction face plates)
are loose on the barrel shaft except when pressed against the friction disc which
gives them motion, or against brake discs which stop them, the said brake discs
being secured to the cheeks of the crane. Hand wheels are secured to nuts
working on a screwed shaft carrying forked levers with fulcrums on a shaft in
such a manner that by turning one or other of these hand wheels either the hoisting
chain pulley, or the opening chain pulley can be moved endways along the shaft
sufficiently to gear into the driving friction disc or the brake discs thus starting or
stopping them at will when the barrel shaft is in motion. A hand wheel is
provided for actuating an eccentric which by a rod and lever connection gives a
cone clutch sliding on a feathered shaft sufficient up and down motion to gear into
and drive either of the two cone clutches. These cone clutches are respectively
cast or secured to bevel wheels and when driven traverse the crane either by gearing
in the usual manner. Hand driving gear is also provided by which all the
operations required for working the grab can be performed by hand power. The
whole is mounted on a Smeaton's ring on a carriage having two large wheels on a
fixed axle and two smaller ones on a swivel axle with drag poles. One hoisting
chain led over pulleys to the chain pulley does the work of closing and hoisting
the grab in a similar manner as in the first arrangement. The opening chain led
over pulleys to the chain pulley also acts in a similar manner to the one in the
first arrangement.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John Henry Johnson in the Great Seal Patent Office on the
18th July 1882.
JOHN HENRY JOHNSON of 47 Lincoln's Inn Fields in the County of Middlesex
Gentleman "IMPROVEMENTS IN SELF ACTING GRABS AND IN THE CRANES OR
APPARATUS FOR WORKING SAME." A communication from abroad by Charles
William Maclean of the City of Melbourne in the Colony of Victoria Engineer.
The said improvements in grabs relate to the contrivances through which the
grappling portion receives its necessary motions of opening, closing, hoisting, and
lowering and the said improvements in the contrivances used for working same
consist first in the substitution of a counterbalance barrel supported on pinions,
running in racks at the back of the crane for the ordinary counterbalance weight
and in so arranging such counterbalance barrel that it assists instead of retards
the engine in all the operations of working the grabs and second in a modified
construction of crane for working the grabs in which it is made a portable
machine.
And in order that the said Invention may be fully understood I shall now
proceed more particularly to describe the same and for that purpose shall refer to
the several Figures on the annexed Sheets of Drawings the same letters of reference
indicating corresponding parts in all the Figures.
Figure 1 is a side view of a crane with the improved grab and counterbalance
barrel attached. Figure 2 is a front view of the grab and Figure 3 is a side view
of the forks when they are substituted for the buckets. Figure 4 is a front view
of crane alone.
The grab A shewn on Sheet 1 of the drawings has pivotted jaws a a¹ with
half buckets b b¹ or forks c c¹ attached. Four links d d d d connect the jaws
with a travelling or rotating shaft e capable of travelling vertically in guides in
the framing of the grab which carries a main pulley and two smaller warping
pulleys g g provided with stops 31 and having warping chains g g each
secured at one end to their respective pulleys and at the other end to the fixed
jaw pivots 30. The grab is fitted with a frame h for keeping the centres in
position, and with guide pulleys kl. The hoisting chains m m' are secured to the
pulley and led to the crane round the jib pulleys n n¹ to the hoisting pulleys
oo which are secured to the shaft p provided with a driving wheel q and brake r.
The engine shaft has a loose spur pinion 8 gearing into the wheel q and is driven
at will by the friction cone clutch t put into gear by the clutch lever u, working on
a fulcrum and screwed shaft w supplied with a nut and hand wheel x. The
ends of hoisting chain are led over pulleys y y¹ y¹¹ yll to the counterbalance barrels
221, which are secured to the shaft 1 provided with pinions 2, 21 gearing into
inclined racks at 3, 31. The said pinions 2, 21 and the racks 3, 3' are shrouded to
the pitch line to form a rolling surface and the guides 4, 4' keep the pinions in
gear. The opening and lowering chain 5 is secured to the pulley f, and wound
round it in a contrary direction to the hoisting chains, thence is led to the
crane round the pulley 6, to the chain pulley or barrel 7, which runs free on the
shaft p; the barrel 7 is fitted with a carrier 8, with a pin 9, projecting into a
friction driving wheel 10 running free on a loose eccentric 11 on the said shaft p.
This eccentric is actuated by a handle 12, by which the friction wheel 10 can be
pressed against the friction driving pinion 13 or against the brake 14, thus
driving or stopping the opening and lowering chain pulley 7. The said friction
driving pinion 13 is secured to the engine shaft 15. The jib 16 is tied by the rods

page_text: 17, 17¹ secured to the wrought iron cheeks 18, 18' connected by the tie rods' shewn:
The table of the crane is provided with a roller path 19 upon which turns the
upper part of the crane and. the water tank 20 formed to support the boiler 21
supplying steam to the engines 22, 22¹. The whole is supported by the Smeaton's
ring of rollers 23, kept in position by a centre wrought iron pin 24, (which is bored
out to allow the boiler feed pipe to pass down below the carriage) and rolling on
the lower roller path which is on the fixed spur wheel 25 secured to the sole
plate 26, which sole plate is provided with bearings wheels and axles 27 if
required. Traversing is performed by the gearing shewn at 28 which is all easily.
accessible for repairs. The cheeks with a roof 29 afford ample protection from
weather.
The various operations of closing and digging, hoisting, opening, lowering and
counterbalancing the grab jaws a a¹ are effected in a novel and improved manner
by the mechanical contrivances herein described as follows:-
Assuming that the grab A is resting in the open position (shown by dotted
lines in Figure 1) on the material to be lifted; the grab is then closed by
putting the chain pulleys o o¹ into gear with the engines when in motion in
the proper direction thus pulling the hoisting chains m m' which being wound
round the pulley f causes the warping pulleys of the grab g g to revolve
drag down the shafte by the warping chains 9" 9 winding round
their respective pulleys and closes the jaws a a¹ with their attached
half buckets b 61 or forks c c¹. During the operation of digging above
described the counterbalance barrels z z¹ take in the slack of the two hoisting.
chains m m¹ and assist instead of retarding as in other machines the engine while
performing the operation of digging. The opening chain 5 being left free winds
round the pulley t and thus gets ready for the opening process during the operation
of digging. The pulling of the hoisting chains being continued after the jaws are
closed the grab with its load is raised the counterbalance barrel still taking in the
slack of the hoisting chains and assisting the operation of hoisting. When the
grab has attained the required height the foot braker is applied to stop the chain
pulleys o o' and the engine is thrown out of gear by the mechanical contrivances
shown. The lever 12 is next used to put the opening chain pulley 7 into gear
with the engine to pull the opening chain 5 which being wound round the pulley f
causes it to revolve until stopped by the stops 31, thus unwinding the warping
chains gg from their respective pulleys and dragging up and opening the
jaws a a¹ with their attached half-buckets b b' or forks c c'. When the grab is
open the lever 12 is used to brake the opening pulley 7 by the gearing herein
described and the grab remains suspended half by the opening chain 5 and half by
the hoisting chains m m¹ and as the latter chains are always acted on by the
counterbalance barrels z z¹ with a force equal to half the weight of the grab the
foot brake r can now be left free and the grab will remain open ready to be
lowered by the opening chain checked by the brake lever 12. While the grab is
being lowered the counterbalance barrel z let out sufficient hoisting chain from
their circumferences to allow the grab to fall to any required depth and at the
same time roll up the shrouding of the inclined racks 3, 3¹ ready for rolling down
when the grab is again raised wrapping the hoisting chains again on their circum-
ferences and acting as a counterbalance to the grab and crane. The weight of
lever 12 acting sufficiently on the friction wheels when the load is being raised
takes in the slack opening chain 5 along with and at the same speed as the
> hoisting-chains. It will be observed that unlike other machines for effecting a
similar purpose the digging in any material of the jaws of the grab is not interfered
with by the counterbalance which assists instead of retards the engine in performing
this operation while the whole weight of the grab bears on the points entering the
material to be lifted. In other machines the counterbalance acts on the opening
chain and therefore counteracts the process of closing the grab and digging the
material to be lifted. In other machines the grab cannot be raised open, but in
the machine herein described the grab jaws can be opened by the opening chain 5

page_text: when the grab is in any position whatever and the grab can be raised while open
to any required height which is often useful in dredging operations where the grab
is frequently closed by accident on immovable objects below water in which case
other machines are troublesome to open. Again in other machines when opening
the grab the load is suddenly transferred from the hoisting chain to the opening
chain which is a severe strain on the chains and other parts of the crane causing
frequent breakages. It will be seen that in the machine herein described the load
is discharged while all the chains are taking part of the strain and there is no
sudden or great strain at any time on either of them.
In order to make the crane in a portable form the boiler engine and counter-
balance shown on Sheet 1 of the drawings may be left out and the various
operations of digging, hoisting, opening, traversing and lowering the grab without
these may be performed by a modified form of crane shown on Sheets 2 & 3 of the
drawings in which Figure 1 is side a elevation of the improved portable crane.
Figures 2 and 3 are front and back end views of same and Figure 4 is front
view of the grab. In this modification, arrangement is made for driving by a belt
from either the fly wheel of a separate portable engine or other source of
motive power working a pulley a keyed to a horizontal shaft b which, by bevil
wheels d d' drives the vertical shaft e passing up through the centre pin of the
turn table and driving by the bevil wheels f f the barrel shaft g which has a
friction disc h keyed to it. The hoisting chain pulley k and the opening chain
pulley (each with special friction face plates) are loose on the barrel shaft g
except when pressed against the friction disc h which gives them motion or against
the brake discs m n which stop them-the discs m and n being secured to the
cheeks o, p of the crane. The hand wheels q r are secured to nuts working on the
screwed shaft & carrying the forked levers u v with fulcrums on the shaft win such
a manner that by turning one or other of these hand wheels either the hoisting
chain pulley k or the opening chain pulley can be moved end ways along the
shaft sufficiently to gear into the driving friction disc h or the brake discs m n thus
starting or stopping them at will when the barrel shaft g is in motion. The hand
wheel is provided for actuating an eccentric which by the rod y and lever gives
the cone clutch 1 sliding on the feathered shaft 2 sufficient up and down motion
to gear into and drive either of the cone clutches 3 or 4. These cone clutches 3, 4
are respectively cast or secured to the bevel wheels 5, 6 and when driven traverse
the crane either way in the usual manner by the gearing shewn. Hand driving
gear is also shewn at.7 by which all the operations required for working the grab
can be performed by one or two men standing on the platform 8. The platform 9
is for the one operator required when the crane is driven by a separate engine.
The jib 10 is supported by the tie rod 11 attached to the wrought iron cheeks.
A digging grab fork is shewn at 12. The whole is mounted on a Smeaton's
ring 13 on a carriage 14 having two large wheels on a fixed axle 15 and two
smaller ones on a swivel axle 16 with drag poles 17. One hoisting chain 18 led
over pulleys 20 and 21 to the chain pulley e does the work of closing and hoisting
the grab in a similar manner to the two shown in Sheet 1 of the drawings. The
opening chain 19 led over pulleys 22 and 23 to the chain pulley k acts in a similar
manner to the one shewn in Sheet 1 of the Drawings.
Having thus described the nature of the invention and the manner of performing
the same I would have it understood that I do not claim broadly the use of cranes
for working self-acting grabs nor yet the grabbing portion of the buckets and
forks herein described and illustrated in the Drawings but what I consider to be
novel and original and therefore claim as the Invention secured to me by the
herein before in part recited Letters Patent is :-
First: Constructing self acting grabs with a travelling shaft working vertically
in guides in the framing and carrying first a drum or main pulley to which are
attached the closing and hoisting chains as well as the opening and lowering
chain;
and Secondly two warping pulleys for winding and unwinding the chains
which open and close the two halves of the bucket and to which are also attached

page_text: the links or levers d and d¹ all substantially in the manner and for the purposes
described.
Second-Connecting the counterbalance weight or its equivalent to the closing
and hoisting chains so that it assists instead of retards the Engine in this portion
of its work.
Third Constructing the counterbalance of a barrel supported by pinions
running in a rack set preferably on an incline and at the hinder part of the crane
so that it may counterpoise it as well as counterbalance the grab substantially as
berein described and explained.
:-
Fourth The special combination and arrangement of machinery shewn on
Sheet 2 of the Drawings and constituting the improved portable crane.
In witness whereof I the said John Henry Johnson have to this my
Specification set my hand and seal this seventeenth day of July One
thousand eight hundred and eighty two.