car for Working the same.
Year: 1887

page_text: Date of Application, 4th Mar., 1887
Complete Left, 3rd Dec., 1887
Complete Accepted, 2nd Mar., 1888
car
for Working the same.
1, GEORGE TIPPING PETERS of 3 Sunny Bank, Lyncombe Vale, Bath, in the County
of Somerset, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to improvements in the construction of grabs and grab
diggers and also to improved gear or means whereby I am enabled to lift, suspend,
open and lower the said grabs or grab diggers withoutr eversing the engine or requiring
to lift to disengage the grab or grab digger from the suspending medium; also to
close and re-open the grab or digger at the bottom of its descent, if required, without
having to return it to the jib head or suspender.
I construct my improved grab digger in four segments or blades, which, when
closed, fit together and form a square-topped grab digger. Each segment is provided
with two arms and the arms of opposite segments are pivotted on the same centre. To
the outer side of one, two or more of the said segments I secure tines or picks so
arranged as to dig and prepare the ground for the next descent of the grab.
The closing gear of smaller and large barrels is fixed in an annular or other suitably
shaped frame. The barrel-shaft passes through the said frame and forms the centre
on which the arms of two opposite segments are pivotted. The arms of the other two
segments are pivotted to the said frame at right angles to the barrel-shaft but in the
same horizontal plane.
Two main connecting rods are pivottally connected to the top edge of each of the
two blades which are pivotted on the barrel-shaft. The said connecting rods extend
ΓΗ

page_text: upward and converge towards a central joint, as described in the specification of Letters
Patent granted to me on January 9th 1885 No. 302. Two connecting rods are
connected to each of the other two blades in the same manner as the main connecting
rods, and these connecting rods also converge upward and may be connected to the
connecting pins of the main connecting rods by an intermediate joint piece or other
suitable connection, or they may be jointed to the main connecting rods.
The chains from the small barrels are connected to the joint pins of the main
connecting rods, so that the act of closing, draws the centres of the connecting rods
and barrel together, the closing strain being down the four sets of connecting rods.
My improved grab may be used with the suspending loops or forked lever herein-
after described or it may be suspended from a loose hanging chain from the crane jib
or other support or from a self-centreing ring as described in my former specification
or it may be used without any suspending medium, or with a double instead of a
single chain by dispensing with the mechanism and suitably fastening the opening
chain to the tops of the connecting rods.
When the grab is suspended from the suspending loops or ring I use compound
catches pivotted between the main pair of connecting rods, each of the said compound
catches consisting of a suspending or hook catch and a chain gripper similar to those
described in the specification of my former patent above referred to, but, instead of
each pair of suspending catches and chain grippers being pivotted on one centre I
introduce an intermediate link-piece as hereinafter described between the said catches
and grippers. I also use the pulley chain-guide described and shown in the said
specification, or other suitable form of chain-guide. For the purpose of effecting the
opening of the grab at the bottom of its descent independently of the suspending
medium dispense with the sliding movement of the connecting rods and their springs
(as described in the above-mentioned specification) and substitute therefor the above-
mentioned intermediate link-piece between the suspending and gripping catches, the
said intermediate link-piece being keyed to the shatt on which the said chain-
gripping catches work freely, and the suspending catches being jointed freely to the
intermediate link-pieces. The said intermediate pieces are so arranged as to admit of
each of the suspendling or hook catches operating independently of the chain-grippers.
The suspending catches are controlled by push-rods connected at their lower ends
to the sides of the grab-bucket and the said push-rods are either spring ended at
their upper extremities or arranged to govern the said catches by a suitable balance
weight or spring connection. The said push-rods are so arranged that when the grab
is open they will push in the suspending catches and the said catches so act upon
the chain-grippers as to force the said chain-grippers away from the lifting chain
until the said chain gets a start to close the grab. The suspending rods of the
chain-guide have a crank or eccentric connection with the pivot shafts of the
gripping-catches. When the chain is lifted the strain on the guide, due to the angle
of pull, acting upon the eccentric connection of the rods by which the chain-guide i
suspended from the pivots of the intermediate link-pieces, will so act upon the sai
link-pieces as to keep the grippers from engaging with the chain until the chain i
slackened. When the lifting chain is slackened and the guide released from strai
the weight of the guide causes the rods by which it is suspended, by their cran
connection with the pivot shafts of the gripping-catches, so to act upon the inter
mediate pieces keyed to the said shafts as to permit the chain-grippers to engage th
chain when it is relifted.
The grab can be discharged or re-opened without a suspending medium by simpl
lowering the said grab on to its bed and running through sufficient of the lifting chair
Instead of the suspending loops or ring I may use a hanging fork or hoo
suspender, suspended by two chains. The one chain may be considered as fixed an
to release the grab it will be sufficient to release only one of the chains and th
weight of the grab will immediately swing the said fork out of the way, so that I ca
treat the releasing of this arrangement in the same way as from the suspending loo
or suspending chain hereinafter mentioned. Or a single chain hanging forked leve
either automatic, as hereinafter described, or otherwise, may be used. In either ca

page_text: the forked lever takes under a flanged connection on the tops of the connecting rods,
the said flanged connection having levers linked thereto arranged to act upon the
intermediate link-pieces above described so as to put the gripping-catches into
position to engage the chain. The hooked suspending catches are dispensed with and
5 the push-rods connected to the intermediate link-pieces.
proper
Or the grab may be suspended from a simple, loose, hanging chain or notched rod
by suspending grippers which will automatically engage with the suspended chain or
notched rod and the said suspended chain or notched rod when not in the
position to engage with the suspending grippers will be made to do so by a suitably-
shaped guide fixed to the tops of the connecting rods of the grab or digger. The
releasing grippers may work freely upon the same
suspending grippers and they will have suitable projections upon them so that they
or separate centres as the
will so govern one another that when the lifting chain is gripped by its gripper the
suspending chain or rod is released from its grippers and vice versa.
re-opening gear already described with this arrangement, the push-rod from bucket
I can use the
being connected to an intermediate link-piece in a similar manner to that described for
the forked lever suspender.
The automatic single chain hanging forkod lever above-mentioned consists of a
weighted forked lever having a tail-piece. The said forked lever is suspended from
one end of a chain which passes over a pulley carried at the end of the jib or other
support and the other end of which chain carries a ring weight through which the
portion of the chain to which the hook is attached passes and works. When the
weight is resting on the top (tail piece) of the hook the said hook is in the engaging
position. When the grab has engaged with the hook and its weight is upon the said
hook, the ring weight is hauled up the required height against a stop fixed on the
suspending chain. The grab then opens out and discharges its contents, it is then
relifted and the weight being taken off the hook, the said hook (being properly
weighted) hangs so as to clear the flanged connection on the grab and allows the grab
to descend. The ring weight immediately comes down upon the tail-piece of the hook
by its own gravity and resets the said hook.
The suspending loops hereinbefore mentioned for use with the hook suspending
catches, consists of two loops, projecting from the lower end of a block which has a
central passage for the lifting chain. The said loops are spread out in a suitable
manner to allow the chain-guide on the upper end of the connecting rods of the grab
to enter between them and so that the hook catches of the grab will take into the said
loops. The said loops and block may be cast in one piece or formed separately and
suitably connected together. The above-mentioned chain-guide is in this case so
formed as to automatically twist round the suspending loops should they not be in
proper position to engage with the suspending catches; otherwise the engaging and
eleasing from the loops is the same as from the suspending ring.
My improved automatic releasing gear for releasing the grab from the suspending
nedium is as follows:-
The chain or chains from the suspender are passed over a
b head and are then led down under a pulley fixed at a convenient position to the
pulley or pulleys in the
nderside of jib. The chain or chains are then connected to a rod which extends to
he upper side of the jib through a suitable guide in the said jib. In the head of
e said rod is a small pulley under which the main lifting chain runs.
od is. also provided with an indent into which fits a catch. The said catch may
The said
connected to a treadle on the main brake treadle or it may be connected to a.
parate treadle, if preferred, so that when the foot is placed upon the upper or
cond treadle the indent is withdrawn from the suspending rod and the suspending
edium pulling down the rod through its guide, also pulls down the lifting chain
hich runs under the pulley at the top of the said rod and, the barrel being
aked the said rod consequently pulls up the lifting chain through the suspender.
e catch gear is thus caused to release the suspender and the grab is ready to
scend. The releasing from suspender and lowering of grab is practically one
ntinuous lowering of the main lifting chain.

page_text: In a crane with derrick motion the grab may be released from its suspender by
simply lowering the jib slightly and in cases where the same height of discharge is
required with a varying derricked height of jib this can be automatically done by
leading the suspending chains over pulleys in the jib head and led down and secured
to a suitable position on the crane bed or frame, the travel of the suspending chains
being taken up by a suitable arrangement of pulleys, if required. I may also use
this suspender arrangement in conjunction with the automatic releasing gear by
leading the chain from suspender over a pulley fixed to the end of the vertical rod
instead of the said suspending chain being fixed to it as described above.
My improved grab may be constructed with or without the means herein described
for re-opening at bottom of descent and either form may be used with or without
the automatic gear above described for releasing from the suspender.
The whole of the automatic apparatus and also gear for releasing from suspender
may also be used with any other type of grab bucket.
T. N. PALMER & Co.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Automatic Grabs and Grab-diggers and in Gear
for Working the same.
I, GEORGE TIPPING PETERS of 3 Sunny. Bank, Lyncombe Vale, Bath, in the
County of Somerset, 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 reference being had to the accompanying
5 drawings forming a part of this specification
My invention relates to improvements in the construction of grabs and grab-diggers
and also to improved gear or means whereby I am enabled to lift, suspend, open and
lower the said grabs or grab-diggers without reversing the engine or requiring to lift
to disengage the grab or grab-digger from the suspending medium; also to close and
re-open the grab or digger at the bottom of its descent, if required, without having to
return it to the jib-head or suspender.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a side elevation of my improved grab with the gear in position to
engage with the suspender, the position of the gear when the grab is at the bottom of
its descent and ready for re-opening being shown in dotted lines.
Figure 2 is a similar view of my improved grab hanging from the suspender, the
position of the gear, when released from the suspender, being shown in dotted lines.
Figure 3 is a side elevation of my improved grab at the bottom of its descent with
gear ready for closing the said grab.
Figure 4 is an end view of my improved grab.
Figure 5 is a plan of the grab-bucket.
Figures 6 and 7 show an arrangement of connecting rods and connections for using
the grab with a double chain.
Figures 8 and 9 are side elevation and plan of my improved grab bucket with
additional blades on two opposite segments thereof.
Figures 10, 11, 12 and 13 are enlarged views of the gear with top chain-guide and
suspender, figure 12 being a plan of the top chain-guide and figure 13 a side elevation
of the suspender.
Figures 14, 15 and 16 illustrate the method of adapting the gear to suspend the
grab from a loose hanging chain or notched rod or any suitable projection on the
said rod, figure 14 being a section on the line of figure 16. Figure 16 is
the notched rod.
Figure 17 shows my improved automatic gear for releasing the grab from the
suspending medium.
Figure 18 shows the automatic levelling gear of the suspender.
Figure 19 shows the automatic releasing gear in combination with the automatic
levelling gear of the suspender.
Like letters indicate like parts in all the figures.
My improved grab-bucket or digger is constructed of four segments or blades A,
which, when closed, fit together and form a square-topped grab-digger, as shown in
figures 1 to 5. Or I form upon two opposite segments of the said grab-bucket or

page_text: digger additional blades A¹, one at each side of the main blade or segment A, as
shown in figures 8 and 9, these segments having thus three points, and the other
segments A being suitably formed to fit between them and close to the positions shown
in dotted lines, figure 8. The blades or segments A and the blades A' all enter the
ground simultaneously, the additional blades A penetrating the corners of ground
between the blades A. They thus help to fill the grab and at the same time partially
break up and level the ground for the next descent of the grab. The segments of my
improved grab may be formed of cast steel or built up with plates and suitable forged
or rolled stiffeners. Each segment A of both forms of grab-bucket or digger is pro-
vided with two arms A and the arms of opposite segments are pivotted on the same
centre. The closing gear of smaller and large barrels is fixed in an annular or other
suitably shaped frame B. The barrel-shaft passes through the said frame and forms
the centre on which the arms of two opposite segments of the bucket or digger are
pivotted as shown at a. The arms of the other two segments are pivotted to the said
frame Bat b, being at right angles to the barrel-shaft but in the same horizontal
plane, see figure 5.
Two main connecting rods Care pivottally connected to the top edge of each of the
two blades which are pivoited on the barrel-shaft. The said connecting rods extend
upward and converge to a central joint C as described in the specification of Letters
Patent granted to me on January 9th 188, No. 302. Two connecting rods D are
connected to each of the other two blades or segments in the same manner as the
main connecting rods Care connected to their segments, and these connecting rods D
also converge upwards and may be connected to the connecting pins of the main
connecting rods C by an intermediate joint-piece or other suitable connection, or they
may be jointed to the main connecting rods C.
The chains from the small barrels may be connected to the joint-pins of the main
connecting rods C or connected to the top chain-guide E (see figures 1 to 4) so that
the act of closing draws the centres of the connecting rods and barrel together, the
closing strain being down the four sets of connecting rods.
My improved grab may be used with the suspending loops hereinafter described,
or it may be suspended from a loose hanging chain from the crane jib or other support,
or it may be used without any suspending medium, or with a double instead of a
single chain by dispensing with the mechanism and suitably fastening the opening
chain to the tops of the connecting rods, as shown in figures 6 and 7, though I do not
limit myself to the preciso arrangement therein shown.
When the grab is suspended from the suspender shown in figure 13, I use two
compound catches pivotted between the main pair of connecting rods, one on each
side of the central joint of the said rods, each of the said compound catches consisting
of a hook catch F and a chain-gripper G similar to those described in the specification
of my former patent above referred to, the grippers having weighted tail-pieces G2,
but provide the said chain-grippers with teeth g or lever equivalent to compel both
to act together. Instead, however, of each pair of suspending catches F and chain-
grippers G. being pivotted on one centre, I introduce an intermediate link-piece H as
hereinafter described, between the said catches and grippers. 1 also use the pulley
chain-guide 1 as described and shown in the before-mentioned specification, or other
suitable form of chain-guide.
For the purpose of effecting the opening of the grab at the bottom of its descent
independently of the suspending medium, 1 dispense with the sliding movement of
the connecting rods and their springs (as described in the above-mentioned specifica
tion) and substitute therefor the intermediate link-piece H between each suspending
hook F and chain-gripping catch G. The said intermediate link-piece H fits withi
a groove in the chain-gripper G and is keyed or suitably fixed to the shaft on which
the said chain-gripping catch G works freely and the suspending catch or hook Fi
jointed freely to the intermediate link-pieces H at f. The said intermediate link
pieces H are so arranged as to admit of each of the suspending or hook catches
operating independently of the chain-grippers G. The suspending catches Far
controlled by the push-rods J connected at their lower ends to the sides of the grab

page_text: bucket, and the said push-rods are either spring ended at their upper extremities or
arranged to govern the said catches F by a suitable balance-weight or spring
connection. In the accompanying drawings, I have shown the push-rods J with
their lower ends pivotted to suitable points J on the bucket and their upper ends
pivotted to levers J2, the said levers being pivotted on pins J³ in the connecting
rods C. The upper portion J of the push rod is jointed to the main portion J at J
so as to have free play outwardly, a stop J being provided on the inner side of the
top of the main rod J. The upper extremities of the rods are connected to pins J'
working in vertical slots F in the hooked catches F. The rods J are governed by
sliding weights J, that is to say, the said weights give the necessary pull inwards to
keep each jointed rod J up against its stop Je during the closing operation, and yet
they allow the suspending catches F and jointed rods J to be thrust out for the
suspending catches F to engage with the suspending loops n as shown in
figure 2, the links or chains being strained out horizontally thereby raising
the sliding balance weights J. When the lifting chain is raised and engaging
with and raising the chain-grippers G the said grippers push off or out the
suspending catches F from the suspending loops n, as shown in dotted lines,
figure 2. The governing gear of push-rods J and J and levers is so arranged
by suitably fixing the centres J and J³ that in the opening out operation (when
suspended by the hanging loops n) the stop Je on top of rod J shall move upwards
and inwards sufficiently, so that when the grab is released from its suspender and
lowered down to the bottom of its descent and the chain slackened, the sliding
balance weights Js shall pull the rods J* in to the stops J and the rods .J* having
pins J7 passing through the slots F in suspending catches F will so control the said
catches that by their bell-crank action with the chain-grippers G, the said grippers
will be thrust away from the lifting chain so that it can be hauled up and the grab
closed. The balance-weights J work between guides secured to the top chain-guide
as shown in figures 10 and 11, the said weights and rods being connected by chains
or links, or the said rods J' may be governed by any other suitable balance arrange-
ment. The action is shown in figures 1 to 3. Or, instead of the above-described
arrangement the upper portions of the push-rods J may be spring ended and connected
to the pins J' working in the slots of the suspending catches F. When the grab
open the said push-rods push the suspending catches F inward, and the said catches
acting upon the link-pieces H at h and through them upon the grippers G at H³ force
the said chain-grippers G away from the lifting chain until the said chain gets a start
to close the grab. The suspending rods of the chain-guide I have a crank or
eccentric connection with the pivot shafts G₁ of the chain-grippers G as shown clearly
in figure 10. These eccentric connections are so arranged that when the chain is
lifted, the strain on the guide due to the angle of pull, acts upon the eccentric
connections of the rods I with the pivot shafts G so as to cause the intermediate
link-pieces H to keep the chain-grippers G from engaging with the chain until the
said chain is slackened. When the lifting chain is slackened and the guide I released
from strain, the weight of the said guide causes the rods I by their crank connections
with the shafts G to release the chain-grippers G from the action of the intermediate
link-pieces H and permit the said chain-grippers to engage the chain when re-lifted.
The tails H of the intermediato link-pieces H may be weighted to assist the action of
the guide I.
The grab can be discharged or re-opened without a suspending medium by simply
lowering the said grab on to its bed and running through sufficient of the lifting
chain.
The action of the gear is as follows:-In figure 1 the grab has just reached the
suspender, closed. On striking against the loops n of suspender n¹ the catches F are
thrust open, (pivotting on the centres, figure 10) but the said catches close on the
said loops by the action of the balance-weights J, which pull the said catches inward.
The grab is now transferred to the suspender, the catches F assume the position
shown in figure 1 dotted lines, the shafts are turned and the chain-grippers G are
thus free to come in to the chain. The said grippers will permit of the chain passing

page_text: .down through them to open out the grab as shown in figure 2, but when the chain is
raised they will engage with the said chain and the bell-crank action of the said
grippers upon the suspending catches F will throw off the said catches as shown in
dotted lines, figure 2, and the grab will be ready to descend. When the grab has
reached the bottom of its descent and the chain has been slackened, the balance-weights
will pull in the jointed rods J* and suspending. catches F and these acting through the
intermediate link-pieces H which are keyed to the pivot shafts G¹, will turn the said
shafts, and the stops on the intermediate link-pieces H will push the chain-grippers G
clear of the chain, so that it can be hauled up and the grab closed by the main chain
being connected to the large barrel which it unwinds whilst the smaller barrels wind
up the chains thereby drawing the centres of the bucket shaft towards the connecting
rod centre. The strain on the roller guide I produced by the closing strain and due
to the angle of pull, so acts upon the cranked or eccentric portion of the shafts Gas
to keep the grippers clear of the chain during the whole of the closing operation. The
grab having closed ascends to the suspender as shown in solid lines, figure 1.
To open the grab at the bottom of its descent, it is only necessary to slack out the
main lifting chain, when the strain on the guide and cranked portion of pivot shafts G¹
being relieved, the weighted tails of the intermediate pieces can now fall and permit
the chain grippers G to engage with the chain, so that when sufficient of the lifting
chain has been run back through the grippers and it is relifted, it will engage with
them, and the connection being now at the tops of the connecting rods C, the grab
will fully open out and the gear will then take the position shown in dotted lines,
figure 2. It is now only necessary to drop the grab again and the whole cycle of
operations can be repeated as often as necessary. By this means the grab can be
worked without any suspending medium by simply resting it on a bed and running
back sufficient chain to open it when it is relifted, the grab can then be opened out,
discharged and lifted, or lowered for its fresh load.
The grab may be suspended from a simple, loose, hanging chain or notched rod, by
suspending grippers which will automatically engage with the suspended chain or
notched rod, and the said suspended chain or notched rod, when not in the proper
position to engage with the suspending grippers, will be made to do so by a suitably
shaped guide fixed to the tops of the connecting rods of the grab or digger. One
portion of the said guide is formed the shape of the lifting chain as shown in figure 16,
so as to prevent its twisting, thereby enabling it the better to engage with the
releasing grippers. The top of the guide is also made with an inclined plane leading
down to the suspending grippers. The releasing grippers may work freely upon the
same or separate centres as the suspending grippers, and the releasing and suspending
grippers are coupled together, so that they will so govern one another, that, when the
lifting chain is gripped by its grippers, the suspending chain or rod is released from
its grippers, and vice versa. I can use the re-opening gear, already described, with
this arrangement, the push-rod from bucket governing in the same way as with the
suspending catches and suspending loops. Figures 14, 15 and 16 show the
arrangement for suspending the grab from a loose, hanging chain or notched rod,
figure 14 being a section on the line of figure 16, showing the grab hanging from
the suspending chain or equivalent. The grab is provided with two sets of grippers
and link-pieces as shown in the drawings, one set for the lifting chain and one set
for the suspending chain. In figure 14, G is one of the lifting chain-grippers
and K is one of the suspending chain-grippers both working loosely upon their
pivot shafts G. H is one of the intermediate link-pieces of the lifting chain-
grippers G, the said link-pieces being keyed fast on their shafts. L is one of
the intermediate link-pieces of the suspending chain-grippers K with tail-piece L', the
said pieces being loose on their shafts. Each intermediate piece H carries a slotted
link-piece M hinged thereto and governed by the push-rods J in the same manner as
the hooked links F hereinbefore described. The link-piece M is connected by a rod H³
to the intermediate link-piece L of the suspending gripper K. The action is as
follows When the grab is closed and being raised to the suspender, the grippers G
are kept clear of the lifting chain by the intermediate pieces H acting upon the said

page_text: grippers at H (the said intermediate pieces being actuated by the pulley chain-
guide 1 through its eccentric connections with the shafts G¹) so that the suspending
grippers K are free to engage with the loose, hanging chain N or notched rod N
carried thereby. After the bucket has opened out, the lifting chain N2 is lifted and
engaging with the grippers G the said grippers act through link-pieces H, link-piece M
and rod H3 upon the link-pieces L of the suspending grippers K, the said pieces L
acting at L upon the grippers K so as to force them from the suspending chain N or
notched rod N and the grab is free to descend.
The suspender hereinbefore mentioned is shown on an enlarged scale in figures 10
and 13. This suspender consists of two loops n projecting from the lower end of a
block n' which has a central passage n' for the lifting chain. The said loops are
spread out in a suitable manner to allow the top chain guide E to enter between them
and so that the hook catches F will take into the said loops. The said loops and block
may be cast in one piece or formed separately and suitably connected together. The
above-mentioned top chain-guide E is formed with inclined surfaces E¹ on the top so
as to automatically twist round the suspending loops n bringing them into position to
engage with the suspending catches F should they not be in proper position to engage
with the said suspending catches. The guide has also a central guide E2 for the main
lifting chain and made the same shape as the chain to prevent the said chain from
twisting and getting crosswise in the chain-grippers. The said suspender has a
swivel connection n³ at its top by which it hangs from the suspending chains.
My improved automatic releasing gear for releasing the grab from the suspending
medium, is shown in figure 17.
The chain or chains from the suspender are passed over a pulley or pulleys O in the
jib-head, and are then led down under a pulley P fixed at a convenient position to
the underside of jib. The chain or chains are then connected to a rod Q which
extends to the upper side of the jib through a suitable guide in the said jib. In the
head of the said rod is a small pulley Q under which the main lifting chain runs.
The said rod is also provided with an indent, which indent may be provided with a
friction roller, and into the said indent fits a catch R. The said catch may be
connected to a treadle on the main brake treadle or it may be connected to a separate
treadle, if preferred, so that when the foot is placed upon the upper or second treadlo
the indent is withdrawn from the suspending rod, and, the suspending medium,
pulling down the rod Q through its guide, also pulls down the lifting chain which
runs under the pulley Q at the top of the said rod, and, the barrel being braked, the
said rod consequently pulls up the lifting chain through the suspender. The catch
gear is thus caused to release the suspender and the grab is ready to descend. Or I
can effect this by simply checking the lowering out of the lifting chain by the ordinary
brake just before the grab has fully opened and the slight surge of the chain thus
produced is sufficient to quietly transfer the grab from suspender to the lifting chain,
or I may increase the surge power, if desired, by weighting a roller which may work
through a guide, as described above, but without attachment to suspender chains, or
may be suitably hinged to a jib of crane or other support. The releasing from
suspender and lowering of grab is practically one continuous lowering of the main
lifting chain.
In a crane with derrick motion, the grab may be released from its suspender by
simply lowering the jib slightly and, in cases where a nearly uniform height of
discharge is required with a varying derricked height of jib, this can be automatically
accomplished by leading the suspending chains over pulleys in the jib-head, the said
chains being led down and secured to a suitable position on the crane bed or frame, or
passed round a pulley T¹ carried by the fixed rod T and connected to the jib as shown
in figure 18.
I may also use this suspender arrangement in conjunction with the automatic
releasing gear as shown in figure 19, by leading the chain from the suspender under
a pulley P on the underside of jib, thence over a pulley Q on the lower end of the
vertical rod and thence under a pulley S to the crane bed or frame, instead of the
said suspending chain being fixed to the rod Q as described above.

page_text: To lift, suspend, open and lower the grab without reversing the engine, by
arrangements shown in figures 17 and 19 the action is as follows:-The grab being
just lowered for a fresh load, the lifting chain is wound up, and the bucket having
closed is lifted up to the suspender, the lifting gear is now thrown out and the crane
slewed round to point of discharge. The grab is then lowered by the brake on to
the suspender and just sufficient chain is let out to open the grab keeping the lifting
chain taut by the brake. The catch is then, withdrawn from the indent in the rod Q
in the manner above described, and the grab is released from the suspender and ready
to descend. The strain on the lifting chain when re-lifting sets the releasing gear
again.
Either form of my improved grab may be used with or without the automatic gear
above described for releasing from the suspender, and the whole of the automatic
apparatus and also gear for releasing from suspender may also be used with any other
type of grab-bucket.
I may protect the mechanism by any suitable contrivance such as plating up from
the sides of the rods, or fixing a frame round top chain-guide, or fixing a bar frame to
the rods extending upward and high enough to protect the push-rods, levers etc.,
when working in confined spaces.
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: :-
:―
First A grab-bucket or digger composed of four blades A having arms A², the
arms of opposite segments being pivotted on barrel-shaft and to the frame B
respectively, substantially as herein described and illustrated in figures 1 to 5.
Second A four-bladed grab-bucket or digger having additional blades A¹ on two
opposite segments. thereof, substantially as herein described and illustrated in figures 8
and 9.
Third The suspender, with or without swivel connection n³, substantially as
herein described and shown in figures 10 and 13.
Fourth-The top chain-guide E adapted for automatically setting the loops of the
suspender to engage with the catches F, substantially as described and shown in
figures 10 and 12.
Fifth-The combination of the catches F, chain-grippers G, intermediate pieces H
and push-rods, substantially as set forth.
Si th-The combination of the catches F, chain-grippers G and intermediate
pieces H, substantially as herein set forth.
Seventh-Chain-grippers with teeth or equivalent, substantially as and for the
purpose set forth.
:-
Eighth The combination and arrangement of gearing for suspending a grab
or grab-digger from a loose, hanging chain, notched rod or equivalent and for
releasing it therefrom, substantially as described and shown in figures 14, 15 and 16.
Ninth The arrangement of gearing for automatically releasing the grab from
the suspender, substantially as described and shown in figure 17.
Tenth The automatic levelling gear, substantially as set forth and illustrated in
figure 18.
Eleventh-The combination of the automatic releasing gear and automatic
levelling gear, substantially as herein described and shown in figure 19.
Dated this 2nd day of December A.D. 1887
T. N. PALMER & Co.,
Agents for the Applicant.