IMPROVEMENTS IN GRAB-BUCKETS FOR DREDGING, EXCAVATING AND ELEVATING to be as follows:
Year: 1884

page_text: I HENRY JAMES COLES of 89 Sumner Street in the Borough of Southwark,
Engineer, do hereby declare the nature of my invention for "IMPROVEMENTS IN
GRAB-BUCKETS FOR DREDGING, EXCAVATING AND ELEVATING to be as follows:-
"
My Invention relates to improvements in the construction of grab-buckets for
dredging and excavating and for raising grain and other matters and the Inven-
tion relates particularly to automatic discharging gear so constructed that the
operations of hooking up the grab, in order to cause it to open and of subsequently
releasing it for the purpose of lowering it again, are performed automatically, and
without any special movement or operation of the hoisting chain being required;
that is to say the bucket can be charged, discharged, and again lowered for
charging, by once raising and lowering the hoisting chain.
The bucket proper is constructed of two similar parts or segments closing
together and working on joints in a frame. This frame is preferably of 1 shape,
to the bottom or cross member of which the segments of the bucket are pivoted,
and the vertical member forms a guide for a sliding crosshead which is coupled to
the segments by pairs of links jointed to the segments at a suitable distance from
their pivoted centres. The vertical member of the frame is of tubular or hollow
construction to give passage to the hoisting chain which passes down through it.
The horizontal member is also of hollow construction and in it are mounted
sheaves, other sheaves being mounted in the sliding crosshead. Branches of the
hoisting chain pass round series of these sheaves in such a way as to form a
multiple purchase whereby the act of hoisting the chain tends to draw the sliding
crosshead down on to the horizontal member of the frame and thereby to close the
segments of the bucket together.
The sliding crosshead is furnished with automatic retaining catches which engage
in slots in the vertical guide tube, for the purpose of holding the bucket in the
open position whilst it is being lowered. To enable the bucket to close on reaching
the ground these catches are released by the weight coming on the lip of the bucket
and acting through the coupling links by which the bucket is opened and closed.
For this purpose the catches are provided with tail pieces in position to be acted
on by the coupling rods, and the latter have a sufficient amount of play at their
Prine d

page_text: joint with the sliding crosshead, to permit of such motion independently of the
crosshead as to cause the catches to be released, and leave the bucket in readiness
to be closed by drawing up the hoisting chain.
The guide tube or vertical member of the frame is preferably made of rectangular
section and is terminated at its upper end by a circular head or crown for a purpose
hereafter described.
The automatic discharging gear consists of a ring of pendent catches adapted to
engage with a circular flange on the sliding crosshead and to retain said crosshead
whilst the main frame is lowered, and thereby cause the bucket to be opened for
the purpose of discharging its contents.
These catches are supported by vertical rods hung from a support on the jib-head
said rods being assembled together at the lower part by a ring.
The catches are automatically pressed inwards for the purpose of engaging
with the flange of the crosshead and their motion in either direction is limited
by stops.
In order to release these catches (for the purpose of lowering the bucket in the
open position) by the mere act of lowering the hoisting chain without performing
any special motion for the purpose of releasing them, the head or crown (before
mentioned as being provided on the upper end of the guide tube) is caused to act
on inclined projections on the catches and to force them outwards thus releasing
the sliding crosshead.
The hoisting chain passes down between the rods pendent from the jib head as
above described, and the said rods are maintained equidistant from the chain by
means of a loose disc or its equivalent, forming a distance piece, through the centre
of which the chain passes freely, and which is adapted at the circumference to
embrace and slide upon the pendent rods.
The disc serves to keep the lower ends of the pendent rods parallel to the chain
so as to ensure the head or crown of the vertical member or guide tube of the bucket,
entering between the catches; whilst being free to slide up within the rods it forms
no obstacle to the continued ascent of the said head or crown.
The action of this automatic discharging gear is as follows:-On the ascent of
the loaded bucket the crown of the vertical guide tube is at its maximum distance
above the sliding crosshead and enters between, and rises completely above, the
catches in advance of the flange of the sliding crosshead, leaving these catches in
their normal position. The said flanges then enters between the catches and
becomes automatically engaged thereby. The hoisting chain is now slackened,
and the bucket is thereby caused to open by the guide tube descending whilst
the sliding crosshead is held by the catches, in which position it is retained, until
by the continued descent of the said guide tube, its head or crown strikes the
inclined projections on the catches, and forces them outwards thus causing them
to release the sliding crosshead. The bucket is thus entirely freed from the catches
by simply continuing without interruption the lowering motion, necessary for
opening it. At the moment that the crown is about to act upon the catches in
the manner above described the retaining catches on the sliding crosshead fall
into position to prevent the closing of the bucket, whilst being further lowered
for re-loading.
Dated thin 19th date of Annunt AD 1001

page_text: I HENRY JAMES COLES of 89 Sumner Street in the Borough of Southwark,
Engineer, do hereby declare the nature of my invention for "IMPROVEMENTS IN
GRAB-BUCKETS FOR DREDGING, EXCAVATING AND ELEVATING" 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 the construction of grab-buckets for
dredging, and excavating, and for raising grain and other matters, and the invention
relates particularly to automatic discharging gear so constructed that the operations
of hooking up the grab (in order to cause it to open) and of subsequently releasing
it (for the purpose of lowering it again) are performed automatically and without
any special movement or operation of the hoisting chain being required; that is to
say the bucket can be charged, discharged and again lowered for charging, by once
raising and lowering the hoisting chain.
In order that the invention may be more readily understood I have illustrated it
in the accompanying drawings forming part of this Specification and will proceed
to describe it with reference thereto.
Figure 1 is an end elevation of the bucket closed, the position of the links and
sliding cross-head when the bucket is held open being represented in dotted lines.
Figure 2 is a side elevation of the bucket, closed. Figure 3 is a vertical section on
the line 1-1 figure 2 showing the sliding crosshead and catches in the position
they occupy when the bucket is held open. Figure 4 is a plan of the sliding
crosshead. Figure 5 is a plan of the horizontal member of the frame, the vertical
member being in section. Figure 6 is a plan of the conical head or crown of the
frame. Figure 7 is a plan of the flange of the sliding crosshead. Figure 8 is a
side elevation of the automatic discharging gear, the flange of the sliding crosshead
being shown as engaged with the pendent catches. Figures 9 and 10 are respectively
a front elevation, and plan, of the same. Figure 11 is a plan of the pendent catches.
Figures 12 and 13 are horizontal sections showing details hereafter referred to.
Figure 14 is a general view of the bucket as held open by the automatic discharging
gear. Figure 15 is an end, and Figure 16 a side elevation of a bucket provided
with a modified form of multiple purchase. Figure 17 is a plan of the conical
head.
The same letters of reference indicate the same or similar parts in all the
figures.
The bucket proper is constructed of two similar parts or segments A, A, closing
together and working on joints in a frame B. The segments A are shown as
constructed partly of plates and partly of tines forming serrated jaws, but they
may be of any other construction suitable for the nature of the material to be
operated on. The frame B is preferably of 1 shape, to the bottom or cross
member B¹ of which the segments A, of the bucket, are pivoted at a, and the
vertical member B forms a guide for a sliding crosshead C which is coupled to the
segments A by pairs of links D jointed to the segments at a suitable distance from
their pivotal centres a. The vertical member B of the frame is of tubular or
hollow construction, to give passage to the chains which pass down through it. It
is preferably of rectangular section formed of a pair of 1 shaped plates rivetted to
a pair of channelled irons as shown in the section figure 4, but it may be of any
other suitable form and made in any other way. The horizontal member B' is also
of hollow construction, being formed of a pair of channelled irons with distance
pieces between them at the ends to which they are rivetted as well as to the cross

page_text: end of the plates of the vertical member B as shown in figure 5, the said distance
pieces also forming eyes for the pivot pins a. In the horizontal member B¹ are
mounted sheaves E, and in the sliding crosshead C are mounted other sheaves F
round which branches G¹, G¹, of the hoisting chain G pass in such a way as to form
a multiple purchase as shown in figure 2, whereby the act of hoisting the chain
tends to draw the sliding crosshead C down onto the horizontal member B¹ of the
frame and thereby to close the segments A A of the bucket. The branches G¹ of
the hoisting chain must be of sufficient length to pass round their respective sets of
sheaves when the crosshead C and the frame B' are at their maximum distance
apart, but they may be of any greater length and might even be continued as two
separate chains to the crane barrel, although they would always, virtually, constitute
but a single chain.
The crosshead C is adapted to slide freely upon the vertical member B of the
frame, and it is furnished with automatic retaining catches c which are pivoted to
it and engage in slots b in the vertical guide tube B for the purpose of holding the
bucket in the open position, whilst it is being lowered as shown in figures 1, 5,
and 14. To enable the bucket to be closed on reaching the ground these catches
are released by the continued descent, together, of the frame and crosshead after
the weight of the bucket has come on the points of the tines or lips of the
segments A. For this purpose the spindles of the catches c, are provided with
levers or tail pieces c¹ in position to be acted on by lugs d on two of the coupling
rods D, and the said coupling rods are slotted at d' where they take on to the
gudgeons of the sliding crosshead, so as to permit of a sufficient amount of play
to allow of such independent motion of the crosshead as to cause the catches to be
released from the slots b and leave the bucket in readiness to be closed on drawing
up the hoisting chain. The levers or tail pieces c' also act as weights to throw the
catches into the engaged position at the proper time. The guide tube or vertical
member B of the frame is terminated, at is upper end, by a circular head or crown H
for a purpose hereafter described.
The automatic discharging gear shown in figures 8 to 13 consists of a set of
pendent catches I (preferably three or more in number) arranged in a circle and
adapted to engage with a circular flange C¹ on the sliding crosshead C when the
said flange is drawn up a sufficient distance within them, and to retain said cross-
head whilst the main frame B, B' is lowered and thereby cause the bucket to be
opened for the purpose of discharging its contents. These catches I are preferably
double, and are pivoted at i to a frame composed of vertical rods K which are
assembled together by a frame L at the upper part and by a ring M at the lower
part. The catches I are automatically pressed inwards by springs i¹, or by weights,
for the purpose of engaging with the flange C of the crosshead.
In order to release these catches (for the purpose of lowering the bucket in the
open position) by the mere act of lowering the hoisting chain G without performing
any special motion for the purpose of releasing them, the head or crown H on the
upper end of the guide tube B is, by the continued descent of the frame B inde-
pendently of the crosshead C, caused to act on inclined projections on the inner
edges of the catches and to force them outwards, thus releasing the sliding cross-
head. To prevent the crown H, itself, from being caught by the catches (after the
flange C has been released) it is preferably made of conical form.
The rods K extend below the pivots i of the catches I a sufficient distance, and
sufficiently close to, the flange of the crosshead, to keep the catches concentric
with the flange of the crosshead at the moment of their release-so as to ensure
simultaneous action of all the catches.
Owing to the concentric circular arrangement of the catches I, and the form of
the flange C' and crown H, the action of the automatic discharging gear is unaffected
by any rotary motion which the bucket may have on the chain as an axis whilst
being raised and lowered.
The hoisting chain G passes down between the rods K pendant from the jib-head
as above described, and the said rods are maintained equidistant from the chain by

page_text: means of a loose distance piece N which is adapted to embrace and slide upon the
pendent rods K and through the centre of which, as well as through the centre of
the top frame L, the double hoisting chain passes freely. This distance piece serves
to keep the lower ends of the pendent rods parallel to the chain so as to ensure the
head or crown H entering between the catches I whilst the distance piece being
free to slide up within the rods forms no obstacle to the continued ascent of the
said head or crown.
The action of this automatic discharging gear is as follows:-On the ascent
of the loaded bucket the crown H is at its maximum distance above the sliding
crosshead C, and enters between and rises completely above the catches I in advance
of the flange C of the sliding crosshead, leaving these catches in their normal
position. The said flange C¹ then enters between the catches I and becomes auto-
matically engaged thereby, as shown in figures 8, 9 and 14. The hoisting chain is
now slackened and the bucket is thereby caused to open by the frame B B
descending, whilst the sliding crosshead C is held by the catches I, in which
position it is retained until by the continued descent of the frame B B', its head or
crown H strikes the inclined projections on the catches I and forces them outwards
thus causing the release of the sliding crosshead C. The bucket is thus entirely
freed from the catches I by simply continuing without interruption the lowering
motion, necessary for opening it. At the moment that the crown H is about to act
upon the catches I in the manner above described, the retaining catches c on the
sliding crosshead C fall into position in the slots bas shown in figure 3 to prevent
the closing of the bucket whilst it is being further lowered for reloading. On the
bucket striking the ground the catches c become disengaged by the links D
supporting their tail ends, whilst the crosshead continues to fall as before described,
and the bucket is then free to close when the chain is hauled up.
In the modification shown in figures 15, 16 and 17 the sheaves E, F are replaced
by a triple sheave of two diameters mounted in the frame B, the lower member of
which is modified in form to receive it, as shown. The hoisting chain is attached
to, and wound on, the part of larger diameter, and the branch chains are wound
on the parts of smaller diameter and are attached thereto and to the sliding
crosshead C. The main and branch chains being wound in opposite directions the
uncoiling of the one causes the coiling up of the others, and vice versa, in the well
known way. In other respects the construction and operation of the bucket arc
the same as before described.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:-
1. The combination of mechanism constituting the automatic discharging gear
for a grab-bucket and consisting, essentially, of a crosshead sliding on the main
frame of the bucket and adapted to engage with catches carried by an overhead
support, and of a crown or head or its equivalent on the main frame adapted to act
on the catches for the purpose of releasing the crosshead, the said crosshead and
crown respectively acting in conjunction with the other parts of the grab bucket,
substantially in the manner described for the purpose specified.
2nd The particular construction and arrangement of the automatic discharging
gear for a grab-bucket, substantially as described, and consisting of three or more
radial catches arranged in a circle, acting in combination with a circular flange on
the sliding crosshead and with a circular head on the main frame of the bucket,
whereby the engagement and release of the catches is automatic and unaffected by
any rotary motion of the bucket on the chain as an axis.
3rd The combination of mechanism for retaining the grab-bucket in the open
position until it strikes the ground, and consisting, essentially, of the catches on
the sliding crosshead adapted to engage in slots in the frame and their spindles and
tail pieces, acting in conjunction with the coupling rods and their lugs whereby the
catches are released from the slots by the independent motion of the crosshead and
frame, as described,

page_text: 4th The general combination and arrangement of mechanism herein described
applied in connection with a grab-bucket worked by a single chain whereby the
operations of charging, raising, discharging, and lowering the bucket ready for
again charging, are performed automatically by merely once raising and lowering
the chain, as herein described and shown in the drawings.
5th The combination with the sliding crosshead for working the the segments
and with a multiple purchase as herein shown and described, of a frame having a
central guide for the crosshead made tubular to give passage to the chains, sub-
stantially as described.
6th The particular arrangement of multiple purchase shown in figures 24 and 5
and consisting of series of sheaves mounted respectively in the horizontal member
of the frame and the sliding crosshead, and of branch chains passing around the
same as described, the sheaves being contained within the thickness and depth of
the frame and crosshead respectively so as to occupy no space in the bucket, or
require any extra length of frame to accomodate them.
7th The particular construction of the 1 frame shown in figures 24 and 5,
consisting of pairs of plates united to distance pieces, to form a hollow structure
for the passage of the chains and to receive the sheaves, substantially as specified.
Daved ains 180 day of December 1804.
H. J. COLES.
By his Agents, A. M. & Wm Clark,
53, Chancery Lane, W.C.