IMPROVEMENTS IN GRABS BUCKETS OR SKEPS
Year: 1885

page_text: I NATHAN GOLD KIMBERLEY of Tottenham in the County of Middlesex Engineer
do hereby declare the nature of my Invention for IMPROVEMENTS IN GRABS
BUCKETS OR SKEPS to be as follows:-
My Invention relates to Improvements in Grabs Buckets or Skeps for raising
or discharging grain or other cargoes for excavating or dredging and for other
purposes.
The grab bucket or skep of my invention hereinafter indiscriminately called the
grab is made to open and close by the mere operation of raising or lowering it and
is constructed in a compact form without the frames and guides commonly used
which get out of order and make the apparatus liable to turn over when dropped
on uneven ground.
The grab proper may be of any form to suit the requirements of the work and is
made in two parts each pivotted at their outer sides to the suspending rods and at
their inner ends to plates fixed to the end of spindle on which are placed the barrels
to which the lifting and closing trains are attached.
The suspending rods are pivotted at upper ends to the corners of the crosshead
and provided with suitable stops to limit their radial movement.
To the underside of the crosshead are attached the closing chains and to the
upperside is connected a means of suspending the grab independently of lifting
chain. In apparatus controlled by two chains this is accomplished by a chain
leading away parallel to the lifting chain and in those operated by a single chain it
is accomplished by a suitable detaching and retaining gear.
I construct my grab with automatic detaching and retaining gear as follows.
The Crosshead is provided with a headed hollow spindle through which passes
the lifting chain and upon which slides a sleeve. This sleeve is connected to the
sliding blocks in the crosshead which are caused to move vertically by the radial
movement of suspending rods Detents are provided to keep the grab open by
locking the sliding blocks in their highest position. These detents are controlled
by springs which tend to keep them away from blocks except when grab is in its
highest position.

page_text: A frame or other arrangement hereinafter indiscriminately called the frame is
suspended from the jib head or other structure to temporarily support the grab
independently of the lifting chain.
Inside the frame proper I place one or more sliding frames with two sets of
catches one set to suspend the spindle of grab within the sliding frame and the
other to suspend the sliding frame within the frame proper.
The mode of operation is as follows. Suppose the grab to be closed and to be
ascending. The sliding frame is in its lowest position and the catches are free. As
the spindle of grab enters sliding frame the head engages with a projection on
sliding frame carrying it with it. One set of catches come in contact with frame
proper which moves them until they project under the head of the spindle and
locks them there, the other catches now engage with the frame proper and are there
locked by the motion of the sliding sleeve. The springs of detents have come in
contact with frame and press the detents against sliding blocks.
On the chain being lowered the catches which suspend the sliding frame will rest
on frame proper and so cause the crosshead to which are connected the outer sides
of halves of grab proper to remain stationary whilst the inner ends of grab proper
descend with the chain opening the grab and so discharging the contents.
The radial motion of suspending rods due to the opening of grab causes the
sliding sleeve to rise to its fullest position liberating the catches which suspend the
sliding frame and being itself retained by the detents falling into notches in sliding
blocks. These catches now being free the weight will again be taken by chain and
grab and sliding frame will descend together until the catches which suspend the
hood of spindle are clear of frame proper when they will allow the head of spindle
to pass them and will remain in that position ready for the return of the grab. As
long as the weight of grab is on lifting chain it causes the sliding blocks to grip the
detents sufficiently to prevent their withdrawal by their springs but as soon as
the weight is taken by the ground or other medium the springs will withdraw
the detents and as soon as the chain is drawn up the grab will close and then
ascend.
The foregoing arrangement provides for the whole of the operations being
performed by simply lifting the grab to its full height and lowering it again but as
a modification of this I propose to perform them by lifting the grab onto the catchies
allowing it to remain there until it has discharged its contents then lifting it clear
and lowering it. This requires more time to carry out the operation but will admit
of the mechanism being simplified. In this arrangement I dispense with the
sliding frame and use only one set of catches which may be on either frame or grab
I do not attach the sliding sleeve direct to the sliding blocks as before but arrange
it so that the latter communicates an upward motion to the former through springs
but a downward motion direct arrange the detents as before or provide an arrange-
ment by which the sliding sleeve withdraws them when the weight is taken off the
chain.
The mode of operation of this modification is as follows.
Suppose the grab to be closed. It is liſted until the head of spindle passes the
catches. On lowering the chain these catches hold back the spindle and the grab
opens as before and the upward motion of sliding blocks due to the radial movement
of suspending rods compresses the springs causing the sleeve to press against
underside of catches. On the chain being lifted the hold of sliding blocks on
detents is tightened so keeping the grab open and any further lifting causes the
catches to be pushed out by the sliding sleeve which under the action of the springs
follows them up and by partially closing the space between it and head of spindle
prevents their return when grab is lowered. When the weight of grab is taken by
sufficiently resisting medium the grip on detents is relieved and they are freed by
the further travel upward of sleeve under the influence of springs and on the chain
being lifted the grab will close and then ascend.

page_text: It is evident that when the automatic action is not required the automatic gear
previously described might be replaced by other arrangements for suspending the
grab independently of lifting chain such as a frame which may be placed under
the head of spindle and removed by hand or other means.
Dated this tenth day of March One thousand eight hundred and eighty five.
NATHAN GOLD KIMBERLEY of Tottenham in the County of Middlesex, Engineer
do hereby declare the nature of said invention and in what manner the same
is to be performed, to be particularly described and ascertained in and by the
following statement :-
My Invention relates to "Improvements in grabs buckets or skeps, for raising
or discharging grain or other cargoes for excavating or dredging and for other
purposes.
The grab bucket or skep of my invention hereinafter indiscriminately called
"the grab" is made to open and close by the mere operation of raising and
lowering it and is constructed in a compact form without the frames and guides
commonly used which get out of order and make the apparatus liable to turn
over when dropped on uneven ground.
The grab proper which may be of any form to suit the requirements of the work
is made in two parts each pivotted at its inner corners to the ends of spindle
carrying the barrels to which are attached the lifting and closing chains and at its
outer sides to suspending rods pivotted to the crosshead to which are attached the
closing chains and an arrangement for suspending the grab whilst the lifting chain
is being lowered to discharge its contents. In "double chain grabs" this arrange-
ment consists of a chain leading away parallel to lifting chain and in "single chain
grabs it consists of a suitable detaching and retaining gear. This gear may
consist of a frame or rest which can be placed under the head of crosshead spindle
and removed by hand or otherwise or an automatic apparatus comprising a frame
suspended from a jib head or other structure and suitable appliances on grab. Two
kinds of these frames are used, one hereinafter called the "automatic frame'
provides for the performance of the whole of the operations by simply lifting the
grab to its full height and lowering it again but the other hereinafter called the
simple frame" requires the grab to be lifted on to its catches and allowed to
"

page_text: remain there until it has discharged its contents then lifted clear of catches and
lowered.
"
In the accompanying drawings the same letters indicate the same parts.
Figures 1, 2 and 3 shew the grab with "automatic frame."
Figures 4 and 5 shew the grab with "simple frame."
Figures 6, 7 and 8 show alternative methods of constructing the catches of
'simple frames."
Figures 9, 10 and 11 shew the grab with extra chain in place of frame and
catches.
The grab as constructed for use with "automatic frame" is shewn in Figures 1, 2
and 3. Figure 1 shews the grab closed clear of frame. Figure 3 shews the upper
part of closed grab raised to its highest position and resting on frame. Figure 2
shews the lower part of grab open. A is the grab proper made in two parts each
pivotted at a to plates B and at a¹ to the suspending rods D. These rods are
pivotted at e to the crosshead E and provided with arms D¹ engaging with the
pins p on sliding blocks P. These blocks form part of the sleeve H which slides on
the spindle F and have a notch p¹ to fit the detent G which is pivotted to the cross-
head and controlled by springs g and g¹. The spindle F is hollow and has a head f
by which the grab is suspended The lifting chain K passes through spindle F and
is fastened at one end to drum c¹ to which are connected two smaller drums c²
having two chains L attached to them the other ends of these chains L are fastened.
to links L connected to the crosshead E. These drums can revolve freely upon
spindle C which is provided with distance pieces c³ and carries the plates B to
which are pivotted the inner corners a of grab proper.
The "automatic frame is shewn in Figures 1 and 3. Figure 1 shews the sliding
frame in its lowest and Figure 3 in its highest position. The frame proper I is
suspended by chains M and contains a sliding frame J which can move vertically
within certain limits. This sliding frame has two sets of catches N and O pivotted
to it. The upper catches N are of a shape suitable for engaging with frame proper
at and head of spindle f. The lower catches O are of a shape suitable for
engaging with frame proper at ² and sliding sleeve H and are provided with
springs 01.
The grab as constructed for use with "simple frames" Figures 4, 7 and 8 is shewn
in Figures 4 and 5. This grab is essentially the same as shewn in Figures 1, 2
and 3 with the exception of the methods of operating sliding sleeve and detent.
In this case the sliding blocks P are separate from the sliding sleeve and transmit
their motion through spiral springs Q and rods q. The detent G is controlled by a
rod g connected to sliding sleeve and acting through spring g.
The simple frame may be constructed in the form of a plain ring as in Figures 7
and 8 with the catches on spindle head.
The simple frame as shewn in Figure 4 consisting of a frame X with a set of
catches x pivotted to it is suitable for grabs arranged as in Figure 4, and the one
shewn in Figure 6 consisting of a frame K with a set of catches provided with
springs y, is suitable for grabs arranged as in Figures 1, 2 and 3.
The grab as constructed in its simplest form is shewn in Figures 9, 10 and 11.
The grab proper A, the drums c¹, c' and spindle C are similar to those already shewn
and described as applicable both to "automatic" and "simple frames" but the
upper part of grab is much simplified. The suspending rods D are pivotted at e to
the crosshead as before but have no extensions. The sliding sleeve etc are
replaced by a separate chain R by which the grab is suspended independently of
lifting chain. The stop pieces d limit the radial movement of suspending rods D.
The mode of operation of grab with "automatic frame" as shewn in Figures 1, 2
and 3 is as follows. Suppose the grab to be closed and to be ascending, the sliding
frame J being in its lowest position and the catches NO therefore free.
spindle of grab enters sliding frame and the head f pushes back the catches O,
which allow it to pass and then return to their normal position under the influence
The

page_text: of springs O', and engages with a projection j on sliding frame J carrying it with it.
The catches N come in contact with which moves them round until they project
under the head f and locks them there. The catches O slip past the projection i³
on the top side of which they rest and are prevented from returning by the sliding
sleeve H which bears against them. The spring g has come in contact with frame
and presses the detent G against sliding blocks P. On the chain K. being lowered
the head will rest on catches N and so cause the crosshead E to which are
connected the outer sides of halves of grab proper A to remain stationary whilst
the inner corners of grab proper A descend with the chain K opening the grab and
so discharging its contents. The radial motion of suspending rods D due to the
opening of grab causes the sliding sleeve H to rise, liberating the catches O and
being itself retained by the detent falling into notch p¹ in sliding block P thus
keeping the grab open. The catches O now being free the weight will again be
taken by lifting chain K and grab and 'sliding frame J will descend together until
the catches N are clear of projection when they will turn and allow the head f
to pass them and will remain in that position ready for the return of the grab.
As long as the weight of grab is on the lifting chain it causes the sliding blocks P
to grip the detent G sufficiently to prevent its withdrawal by its spring but as soon
as the weight is taken by the ground or other medium the spring g' will withdraw
the detent and as soon as the chain is drawn up the grab will close and then
ascend.
"
The mode of operation of grab with "simple frame as shewn in Figures 4 and 5
is as follows. Suppose the grab to be closed. It is lifted until the head of spindle
passes the catches. On lowering the chain K these catches hold back the head ƒ and
the grab opens as before. The upward motion of sliding blocks P due to the radial
movement of suspending rods D compresses the spring Q causing the sleeve H to
press against under side of catches. On the chain being lifted the hold of sliding.
blocks P on detent G is tightened keeping the grab open and any further lifting
causes the catches to be pushed out by the sleeve H which under the action of
springs follows them up and by partially closing the space between it and head
prevents their return when grab is lowered. When the weight of grab is taken by
any sufficiently resisting medium the grip on detent G is relieved and it is freed
by the further travel upward of sleeve H under the influence of springs Q and on
the chain being lifted the grab will close and then ascend.
The mode of operation of grab with "simple frame" as shewn in Figure 6 is as
follows. Suppose the grab to be closed It is lifted until the head of spindle
passes the catches on lowering the chain K these catches hold back the head 'f and
the grab opens as before. The radial motion of suspending rods D due to opening
of grab causes the sliding sleeve H to rise to its highest position and press against
spring y and being itself retained by the detent falling into notch p¹ in sliding block.
On the chain K being lifted the hold of sliding block P on detent G is tightened
keeping the grab open and the springs y¹ push the catches from under the head
of spindle and retain them until the head of grab has passed them when they fall
back to their normal position ready for the return of the grab. When the weight
is taken by the ground or other medium the spring g' will withdraw the detent
and as soon as the chain is drawn up the grab will close and then ascend.
Having now described my invention and the manner in which it is operated,
I wish it to be particularly understood that I do not confine myself to the exact
detail of the arrangements here shewn and described but I do declare that what.
I claim is
1. The general construction of grab as shewn in Figures 9, 10 and 11 substan-
tially as shewn and described.
2. Utilising the radial movement of suspending rods caused by the opening and
closing of grab for operating and controlling the detaching and retaining gear.
3. The general combination of detaching and retaining gear consisting of sliding
blocks moved by the radial motion of suspending rods together with the detent and

page_text: sliding sleeve operated either directly or through springs and rods substantially as
shewn and described.
4. The general construction of "automatic frame" consisting of two frames one
sliding within the other having one set of catches to suspend sliding frame within
frame proper and another set to suspend head of grab within sliding frame
controlled or operated in the manner shewn and substantially as described.
"
5. The combination of head and sliding sleeve of grab with "simple frame as
shewn in Figure 4 in which the sliding sleeve releases the catches in the manner
substantially as shewn and described.
6. The combination of head and sliding sleeve of grab with "simple frame" as
shown in Figure 6 in which the sliding sleeve releases the catches in the manner
substantially as shewn and described.
NATHAN GOLD KIMBERLEY.