Discharging, Re-opening, and Lowering Gear
Year: 1885

page_text: Discharging, Re-opening, and Lowering Gear.
GEORGE TIPPING PETERS, Engineer, 3 Sunny Bank, Lyncombe Vale, Bath, do
hereby declare the nature of said invention for IMPROVED SELF ACTING SINGLE
CHAIN GRAB WITH AUTOMATIC DISCHARGING, RE-OPENING & LOWERING GEAR, to be
as follows:-
This invention relates to an arrangement of Grab, by which I am enabled to lift,
suspend, open & lower, without Reversing the Engines, or requiring to lift to
disengage it from the Suspending ring. Close and re-open at bottom if required
without having to return to the Jib head or Sus, ending ring.
The Bucket or Digger is of the well known form, but with the two halves, con-
nected together by the "Windlass barrel shaft" passing through each half and
secured by washers & cotters or other approved means, & thus making them work
from one centre, which is an essential feature, as I dispense with all framing, used
in the construction of some of the Grabs that are made.
The usual closing gear is used, the main Lifting chain being secured to the large
central Barrel, and the two short side chains from the smaller barrels are connected
to the pins in the tops of the Connecting rods.
To the top edge of the Bucket or Digger are secured the Connecting rods, two on
each side, working on pins, and the centres of rods spread out at bottom to give
lateral stiffness.
The Connecting rods of one half of the Bucket or Digger merge into a Jaw at the
top. In each side of this jaw are riveted the connecting pins. The rods of the
other half are brought up to meet these rods, and a plate slipped over each pin
and outside the other jaw, & secured to the rods, thus making a thoroughly firm
central jointed connection. I do not bind myself to the precise detail of the rods,
but to the principle of the central connection.
Centered in these jaws, are the compound spring catches, one on each side of the
centre line, free to move in and out controlled by their springs.
The vertical part of the catch is arranged to lay hold of the externally flanged
self centreing suspended ring, The lower part having in it an horizontal spring
catch arranged to catch hold of the links of the lifting chain.

page_text: To the underside of the Connecting rod jaws are fixed a swivel chain guide which
will adapt itself to the angle of the rods, being connected to them by rods
uniting in one centre on the chain guide.
In the top of one of the connecting rod jaws, is fixed another chain guide so that
the lifting chain from windlass barrel is kept in the centre by these guides.
Connected to the Bucket or Digger or to their Connecting rods are small push
rods one on each side, leading up to the underside of the Horizontal catches, and
which are arranged so that when the Bucket reaches a certain closing position, the
catches are ready to engage the lifting chain when lowered out again, and when
re-lifted will open out the Grab.
The suspending ring which has an external flange and central hole just large
enough to allow the lifting chain to pass through, so that it cannot swing about
and fail to engage the spring catches of the Grab when it comes up with its load.
To this ring are fastened two chains which lead over a pulley on each side of the
jib, and afterwards connected to a single chain, is carried down to the bottom of
the Jib, (or whatever structure the Grab is worked from,) & coupled to either a
lever, right and left hand screw, or small Hydraulic ram, or any mechanisin that
will lower the suspending ring sufficient to liberate Grab, and governed either by
hand lever or foot treadle, and which can be worked instantaneously with the
releasing of the Main Brake, if need be, occasioning no loss of time.
The modus operandi is as follows:-Suppose the Bucket or Grab with its load is
just being lifted; as soon as the Vertical spring catches touch the outside coned
edge of the suspending ring, they open and allow the ring to enter and then
close on top.
The upper spring catches being thrust open by the ring, the lower horizontal
spring catches are thrust in to the lifting chain and the catches are so arranged,
that the chain can be lowered out, slipping through the catches which yield to its
descent, but engage the chain when re-lifted or the Grab lowered.
The lifting pinion is then thrown out of gear & the chain lowered out by the
Brake. The whole of the weight being now transmitted to the suspending ring,
and the Grab hanging by the top of the connecting rods, open out and the contents
are discharged.
The ring is then lowered sufficient for the Horizontal catches to grip between the
links of the lifting cbain, and the whole weight of the empty grab being then
transmitted to the lifting chain, causing the lower parts of spring catches to rise
sufficiently to thrust off the upper or Vertical catches from the ring & the Grab
then descends by the Brake.
On touching the ground or bottom and the chain slacked an inch or two,
the catches fly off from the chain and allow of its being lifted and the Grab
closed.
In the closing operation the push rods which are connected to the Bucket or
Connecting rods (as the case may be), push up and in the lower spring catches
ready to engage the lifting chain, so that if it is required to re-open the Grab for
another trial, or in case of its having caught in any thing that it cannot pull up
the lifting chain has only to be lowered out enough to open the Grab, and slipping
down through the Spring catches which yield to it in its descent, grip the chain
when re-lifted, and .the connection being then at the tops of the rods, the Grab
opens & frees itself, or is ready for another trial, and so the whole cycle of opera-
tions can be done automatically.
1002

page_text: return the Grab to the Jib-head or to the suspending ring.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 represents the Grab closed, and hanging by the lifting chain from the
windlass barrel, on its way up to the discharging ring, the strain being down the
connecting rods, and Fig. 2 shows the Grab hanging on to the ring fully open and
ready to descend for its next load.
Fig. 3 is an enlarged view of Fig. 1 showing Details of catches and other parts,
and their positions when the Grab is closed and hanging by the lifting chain from
the Windlass Barrel, or with strain down the connecting rods.
Fig. 4 shows Details of the catches, and other parts, when the Grab is hanging on
to the suspending ring, by the upper catches, and it is opened out ready for next
descent.
Fig. 5 shows Details of catches with Horizontal catch or chain grippers having
hold of the lifting chain, and the vertical catches free from the suspending ring,
the Grab being ready to descend for the next load.
Fig. 6 is a Plan of the central joint of the Connecting rods, and the chain guide.
Fig. 7 is an end view of Grab."
Fig. 8. Shows Details of parts of my improved Grab on an enlarged Scale.
Fig. 9. Plan of one of the chain grippers and catches on an enlarged Scale.
Like letters indicate like parts in all the Figures.
The Bucket or Digger is made up of two segments in the usual way, but with
the two halves A. A connected together by the windlass barrel shaft B. The said
shaft passes through each half A. A. of the Bucket, and is secured by washers and
cotters or other approved means.
The balves A. A of the Bucket thus work from the barrel shaft as a centre, and
I dispense with all framing used in the construction of other Grabs to carry the
Barrels and their shaft.

page_text: The usual closing gear is used, the main lifting and winding chain C. being
secured to the large central Barrel and the two short side chains D. D. from the
smaller barrels are connected to the pins E. E. which form the joint in the top of
the connecting rods F. F.
To the top edge of each half of the Bucket or Digger are secured the connecting
rods F. F. two on each half of the bucket. The said rods work on the pins fand
the centres of the said rods are spread out a bottom to give lateral stiffness. The
holes f¹ in the lower ends of the said rods are elongated to permit of the vertical
movement of the said rods.
The connecting rods of one half of the Bucket extend upward and converge
towards a central joint or connection and are formed into jaws at their upper
extremities by plates F' F' rivetted to said rods F. F.
In this jaw are rivetted the connecting pins or pivots E. E. The connecting rods
of the other half of the Bucket also extend upward and converge towards the
central joint; are also formed into a jaw at their upper extremities by plates G. G.
which are slipped over pins or pivots E. E. and then rivetted to the rods F. F. thus
making a thoroughly firm central jointed connection between the two pairs of con-
necting rods, which thus pivot on the pins E. E. Or this central jointed connection,
may be formed in any other suitable manner as I do not bind myself to these
details but to the principle of central connection.
Between these jaws are two compound catches, one on each side of the central
joint, the said catches being pivotted in the said jaws upon the pins H².
The said Compound catches are made up of two separate parts; the vertical
catch H. and the Horizontal catch I. The Horizontal catch I works within a
groove in the lower portion of the said catch H and both of the said catches H
and I work on the pivot pins H2 as shown more clearly in Figs. 8 and 9.
The upper end of the vertical part H of each catch is formed and arranged to
take over the external flange of the self centering suspending ring P. The tail h
of the said catch has in it a pin or pivot H' to which is connected the spring end M'
of push rod M, and said spring end is stiff enough to form the fulcrum or pivot of
catch H when rods F. F. are pressed down when in the act of closing the Grab as
seen in Fig. 3 also when said rods F. F. are pushed up by spring N. the catches
then taking the same position as shown in Fig. 8. The Horizontal catch or chain
gripper I works in the lower part of catch H as aforesaid. The heads of the said
catches I are so recessed as shown at i so as to grasp between them one or more
links of the lifting chain C as shown in Figures 4 and 5 and more clearly in the
enlarged views Figs. 8 and 9.
The gripping catches I are sustained in proper position to engage with the
lifting chain C by springs G¹ as shown.
To the underside of the jaws F1 and G of the connecting rods, a chain guide J
is fixed. The one shown in accompanying drawing, consists of grooved or plain
pulleys, which are kept the proper distance apart by side rods, and which are
properly secured together by bolts or pins passing through pulleys J. These side
rods are pivottally connected to rods K. K., and said rods K. K., are connected to
the pins H2 passing through jaws F¹ and G, thus permitting of the free movement
of the rods F. F.
Instead of grooved or plain pulleys a single hawse pipe may be pivottally con-
nected to rods K. K.
Between the tops of the inner pair of Connecting rod jaws is fixed another
chain guide L. The lifting chain from the windlass barrel is thus kept in the
centre by these guides J and L.
Connected to the Bucket or Digger are push rods M. M. one on each side, the
upper ends of the said rods being connected to the "pins H₁ on catches H. H.
The upper parts of the rods M. M are spring ended as shown at M' to allow of
the free movement of the catches H. H. at their fulcra or pivots in the jaws of the
rods F. F., when in the act of engaging with the suspending ring P.

page_text: The
On each push rod M. a spring N is slipped the lower seat of which fits up against
a collar or stop on said push rod, the upper part of spring N fitting up against the
cross-bar O which is secured to each of the rods F. F as shown in Fig. 7.
said spring exerts an upward pressure on the said cross-bar O and rods F. F.
the said push rods M working through the spring N and cross-bar O and being
connected to catch H as aforesaid.
The push rods M so govern the catches I. I. that at a certain closing point (from
very nearly full open) they will engage the chain when lowered out again, and on
being re-lifted will open the Grab.
The suspending ring P. has an external flange P¹ and a central hole P² just large
enough to allow the lifting chain C to pass through, but preventing it from
swinging about and failing to engage the spring catches H of the Grab when it
comes up with its load. The ring P is of such a diameter that it will so fix the
catches H. H that they will allow the Horizontal catches I. I. to rise sufficiently to
automatically engage the chain C when the said chain is raised or the Grab
lowered.
To this ring P are fastened two chains P³ P each of which leads over a pulley
on each side of the jib or whatever the Grab is worked from and the said chains
are connected to a single chain which is coupled to either a lever, right and left
handed screw, small Hydraulic ram, ratchet or pulley gear, or any other mechanism
governed either by the hand or by foot treadle and by which the Grab is lowered
on to the main lifting chain, and it can be worked so that the lowering process
shall be one continuous movement, occasioning no loss of time by putting the
lifting pinion into gear again to give the necessary lift to free from the ring.
The operation of my Improved Grab is as follows:-Suppose the Grab with its
load is just being lifted as shown in Fig. 1. as soon as the points of the vertical
spring catches H. H touch the outside of the coned lower edge of the suspending
ring P. the said catches open and allow the said ring to enter between them and
then close on top of the external flange P' as shown in Fig. 2. The ring P is of
such a diameter as to open the catches H so that the Horizontal catches or chain
grippers I. I. are now in a position to engage with the lifting chain C as shown in
Figs. 2. 4 and 8. The Spring G¹ will permit of the said chain being lowered out
through the catches I but the said catches will engage with the chain when it is
re-lifted or when the Grab is lowered.
The lifting pinion is now thrown out of Gear and the chain lowered out by the
Brake. The whole of the weight being now transmitted to the suspending ring P.
and the Grab hanging by the pin or pivots H2 in the tops of the jaws of rods F. F.
it opens out and the contents are discharged as shown in Fig. 2.
The ring P is then lowered sufficiently for the Horizontal catches I. I. to grip
between the links of the lifting chain C. The whole of the weight of the empty
Grab being then transmitted to the lifting chain, the catches I. I. rise sufficiently
to throw off catches H. H from the ring P. as shown in Fig. 5. and the Grab
descends by the Brake.
Throughout these operations the fulcrum of catch H is at H2. On touching the
ground or bottom and the chain being slackened, the spring ends M of the push
rods M. thrust up catches H by pivot points H'. The said catches thus force the
catches I. I out of contact with the lifting chain C. causing them to take the same
position shown in Fig. 3. and allow of the chain C. being lifted and the Grab
closed.
In the closing operation the push rods M. M. act upon the catches H and
continue to keep catches I. I. clear of the lifting chain C. or as long as sufficient
strain is put upon rods F. F. acting against spring N.
To re-open the Grab at the bottom of its descent the strain on main lifting
chain C. is slacked (and consequently on side chains D. D.) when the spring N
acting against cross bar O will thrust up the rods F. F. upon their pins fand the
push rods M. being fixtures, the fulcrum of the catches H. H will be changed

page_text: from H² to II and consequently catches H. H will pivot on pins H' and thrust in
or allow catches I. I to automatically engage chain C when re-lifted, as shown in
Fig. 8 the dotted lines indicating the position taken by the catches I as the lifting
chain runs through them. Sufficient chain having been run through the catches I. I
to lift Grab fully open the lifting chain C is then lifted and catches H and I
assume the position shown in Fig. 5 and the fulcrum of catch H is again changed
from H to H. The chain C is then further lifted, the grab opens out and the
contents are discharged or the Grab is ready for the next grab by slackening the
chain C when the catches H and I assume the positions shown in Fig. 3. Thus it
is only necessary to run through a sufficient length of chain to lift Grab fully
open; and if wanted it will be ready for another grab, or the same thing can be
done if the Grab gets jammed or caught in anything that the Crane or Hoist
cannot lift.
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
First. A grab bucket or digger, the two halves A. A of which are pivotted
on and connected together by the windlass barrel shaft B. substantially as set
forth.
Second. A grab bucket or digger having connecting rods F. F. adjustably
pivotted to each half or segment, the said rods converging to and being pivotally
connected at a central point over the barrel shaft substantially as set forth.
Third. The combination of the externally flanged self centering ring P. with the
suspending and discharging mechanism, consisting of catches H. H governed by
springs M and push rods M used to automatically engage the said externally
flanged self centering ring P. suspended from a Crane Jib or other support, and
by means of which the Grab may be temporally suspended, and the contents
discharged, substantially as set forth.
Fourth. The gripping catches or chain stoppers I with springs G¹ or equivalents
constructed and arranged to engage automatically with the lifting chain C, and so
that whilst the Grab is suspended from the ring P. the said lifting chain can be
lowered out freely through the said catches, but when the grab is raised or the
suspending ring P is lowered, the said chain will engage the said gripping
catches I and throw off the suspending catches H leaving the Grab free to descend,
substantially as and for the purpose set forth.
Fifth. The Compound catches H H and I. I. with springs G¹ or their equivalents
in combination with means substantially as herein described whereby the fulcrum
can be changed for effecting the re-opening of the Grab at the bottom of its descent
substantially as set forth.