Improvements in Grabs, Excavator-buckets, or Dredge-buckets.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Grabs, Excavator-buckets, or Dredge-buckets.
SIDNEY MANTHORP COCKBURN Engineer 66 Victoria Street Westminster S.W.
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:
My invention relates to grabs excavator-buckets or dredge-buckets hereinafter
for convenience of description called buckets which are used for raising or dredging
various materials and which are so arranged that they may be allowed to fall open
on the mud or other material to be removed and may be closed and raised together
with a load of the said material.
Extreme difficulty has heretofore been experienced in arranging a simple and
efficient multiple purchase closing gear in circular buckets on account of the limited
space into which it has to be put and so far as I am aware no arrangement exists at
present that can compare with the simplicity and efficiency of the arrangements
found in square or clam shell buckets especially that in which an ordinary windlass
barrel is used running on a shaft.
Now one part of my invention has reference to circular buckets having three or
more pivoted jaws and consists in an improved arrangement wherein the force
applied for closing the jaws of the bucket acts through a multiple purchase.
For this purpose I provide a roller or barrel of convenient diameter and width
formed with a spindle or axle extending from each side of it or fixed upon a spindle
or axle midway between the ends thereof.
The roller and axles together forming what I will hereinafter refer to as the
multiple purchase barrel.
A crane chain is attached to the roller, and chains for causing the jaws of the
bucket to close are attached to the said axles or spindles, which are of smaller
diameter than the roller. I thus obtain a multiple purchase barrel and dispense
with the shaft heretofore used which extends through the multiple purchase barrel
and on which the latter revolves.
The multiple purchase barrel works in a case which consists of two castings,
viz. An upper casting and a lower one.
The lower one has half bearings cast in it to receive the axles of the multiple.
purchase barrel and sockets to receive the pivoted arms of the jaws of the bucket.
Immediately above the arm sockets a substantial flange is formed which serves as
a stop for the bucket arms to strike against when the bucket is dropped open into
mud or other material.
The upper casting is bolted on to the top of the lower one and also has half
bearings cast in it, and a place for a guide roller for the crane chain and also a
socket for the vertical hollow guide on which works a sliding collar. hereinafter
described.
The two castings above described together with the vertical hollow guide I
hereinafter refer to as "the frame" for circular buckets.
The axles of the multiple purchase barrel project through the bearings in the
frame and the chains for closing the jaws of the bucket are attached to the
projecting portions of the said axles.
It is obvious that the case in which the inultiple purchase barrel works, may, if
desired, be made in one piece and provided with a side door for inserting the
multiple purchase barrel and guide roller.
In another modification of my invention I dispense with the multiple purchase barrel
and use two guide rollers or sheaves only. The crane chain in this case is branched
into two and each of the ends taken round one of the sheaves and out through holes
Price 8d1

page_text: in the case attached to lugs on the sliding collar. The case-the socket for the
vertical hollow guide and the sockets for the pivoted arms of the jaws are preferably
cast in one piece. Openings are provided in the case having separate covers
through which the sheaves are introduced. The holes through which the chains
pass to the sliding collar are in the covers.
The application and use of two rollers or sheaves as above described is not new
and forms no part of my present invention but the arrangement and mode of con-
struction of the case with covers and the socket for the vertical hollow guide and
sockets for the arms of 'the jaws together with the vertical hollow guide is new and
is a part of my said. invention.
In buckets of circular form I use cast steel for the pivoted arms of the jaws to
which the plates are riveted. In place of letting the plates extend to the points of
arms as heretofore I cut off the points of the plates and cast a piece on the arm to
fill up its place thus forming a solid steel point to the arm or blade.
Another part of my said invention has reference to buckets of square or clam shell
pattern having two pivotted jaws, and comprises an improyed arrangement of the
inultiple purchase which causes the jaws to be closed and a frame of improved
construction.for carrying the multiple purchase.
For this purpose I provide a multiple purchase barrel as above described for
circular buckets and place it in the frame with its axis at right angles to the axis of
the pivots at the jaws. This frame consists of two broad channels rolled or built up
of plates and angles and of such a width as will take the two pivots of the jaws and
allow sufficient room between the side plates hereinafter described for the width of
the large roller of the multiple purchase barrel.
1 Connecting and riveted to the channels are two flat side plates having at the
lower part cast checks bolted on to them to receive the axles of the multiple
purchase barrel. At the upper part a socket is bolted between the side plates to
receive the vertical hollow guide. Between the side plates, about the centre, are
placed two guide rollers or sheaves. Two plates are riveted to the outside of the
channels to act as stops for the jaws when they are fully open.
The parts above described, that is, the channels stop plates, cast cheeks,-socket
for vertical hollow guide and the guide itself together constitute and form what I
hereinafter refer to as "the frame in square or clam shell buckets.
The axles of the multiple purchase barrel projects through the cheeks and the
chains for closing the jaws are attached to the projecting portions of the said axles a
as above described.
When the multiple purchase barrel is used, one guide roller only is required as a
guide for the crane chain fastened to the large roller of the multiple purchase barrel
but if the multiple purchase barrel is not used the two guide rollers or sheaves may
be used for closing the jaws of the bucket in a manner now commonly in use..
The size of the 'vertical hollow guide, in both my circular bucket and my square
or clam shell bucket, is such as to allow sufficient room laterally for the crane chain
to wind in one lap. two and a half or three times round the large roller of the
multiple purchase barrel without using guide rollers, to prevent surging..
Thus for yard yard and 1 yard buckets I make the vertical hollow.guides of
tubes 4 inches 5 inches and 6 inches in diameter respectively which is much larger
than is necessary except for the purpose above specified.
Another part of my said invention has reference to both circular and square
buckets and comprises the use of a sliding collar, in combination with the other
portions of the buckets as hereinafter described, with catches for engaging with the
vertical hollow guide, for the purpose of retaining the bucket open until it strikes
the ground when the catches disengage from the vertical hollow guide and remain
disengaged that is to say: I provide a sleeve to slide on the vertical hollow guide.
On the lower part of the sleeve a substantial flange is formed on which lugs are
cast to receive the links connecting the collar to the jaws of the bucket, and lugs
to receive the chains for closing the jaws of the bucket. Two hooks with

page_text: A loose
projecting heels are pivoted to the upper portion of the sleeve.
ring, having keys that correspond with key ways on the sleeve, is placed
The said loose ring is put
round the upper portion of the sleeve.
on to the sleeve from the top, the keys on the ring passing down the
key ways in the sleeve the said ring is then turned through a part of a revolution
the keys on the ring passing under projections on the sleeve thus enabling the
sleeve to be lifted by the ring. The two hooks are put into position after the
ring is in place the projecting heels pass through the ring and thus key it in
position. The pins or pivots for the hooks are inserted through holes in the ring.
The ring has two sockets to receive springs and pins which act on the underside
of the projecting heels of the hooks, and causes them to engage with the top of the
vertical hollow guide, so long as the ring is supported in hooks or by some other
When the ring is in its normal
arrangement such as is hereinafter described.
position it rests on the top of the projecting heels and causes the hooks to remain
disengaged from the top of the vertical hollow guide.
The arrangement described above, that is to say-The sleeve, the loose ring,
hooks with projecting heels and the pins and springs &c. I term and hereinafter
refer to as the sliding collar."
The object of my improved arrangement is to provide a sliding collar of simple
and cheap construction having few parts and no minute or expensive details. Each
part is of easy access in case of repair and no fine adjustments are required. The
whole arrangement of sliding collar is applicable to and can be used for either.
square or circular buckets by simply altering the form and position of the lugs cast
on the substantial flange on the sleeve.
A shoulder or flange is formed on the top of the loose ring, which shoulder is
supported in looks suspended from, say; the jib head of a crane to cause the bucket
to. open, when fully open the hooks pivoted to the sleeve engage with the top of the
vertical hollow guide. The bucket can then be lifted open off the suspended hooks
in the usual way.
To render more clear the foregoing description provide the accompanying
drawings in which like letters indicate corresponding parts throughout.
Fig. 1. is a sectional elevation of a circular bucket with 3 jaws and.fitted with
iny improved arrangement of multiple purchase barrel.
Fig. 2. is a cross sectional elevation through the case showing the multiple
purchase barrel and guide roller in elevation.
Fig. 3. is a sectional plan.
Fig. 4. is a sectional elevation of the case cast in one piece.
Fig. 5. is an elevation of the case with the multiple purchase barrel and door or
cover removed.
Figs. 6 and 7 shew in sectional elevation and in plan the solid steel point of
one of the jaws.
The remaining figures of the drawings are hereinafter referred to.
A. is the roller having the axles or spindles B. B. extending one from each side
thereof and forming therewith the multiple purchase barrel. C. is the guide roller
for the crane chain L. which is secured to the roller A. D. and E. are the two
castings forming the case, the upper one D. having a socket F. at the top, for the
vertical hollow guide M. and the lower one having the stop flange G. for the arms !.
of the jaws to strike against, and the sockets H. for the pivoted ends of the said
arms ... are links connecting the sliding collar by the sleeve O. to the arms 1.
K. K. are the plates of the jaws which are riveted to the arms 1. N. N. are the
chains secured to the axles or spindles B. B. and to the lugs on the flange S. of the
sleeve O. The length of the chains N should be such that when they are unwound,
that is, when the sliding collar is at its highest position, the length is only just
sufficient to reach from the lugs on the sliding collar to the axles B. B. of the
multiple purchase barrel so that there is no slack and the chains cannot slip off the axles.
Fig. S. is an elevation and Fig. 9 a sectional plan shewing the modification of my
invention in which I dispense with the multiple purchase barrel.

page_text: 1. I. are, the covers having openings for the passage of the chains Q. Q. which
are passed round the sheaves R. R. in the ordinary way and are attached to the lugs
on the flange S. on the sleeve O.
Fig. 10. is an end elevation of a square or clam shell bucket having two jaws the
sliding collar being shewn in section.
Fig. 11. is a side elevation of the same bucket.
Fig. 12. is a sectional plan of the sliding collar.
Fig. 13. shews part sections of the sliding collar drawn to an enlarged scale.
Fig. 14. is a section through the frame shewing the multiple purchase barrel and
guide roller in elevation.
O. is the sleeve of the sliding collar with the substantial flange S on the lower
part on which lugs Tare cast to receive the links J. U. U. are the hooks or
catches provided with projecting heels V and pivoted to the upper part of the
sleeve O. so that they may engage with the top of the vertical hollow guide M.
W is the loose ring with the sockets X for the springs Y and pins Z and with the
flange or shoulder A' on the upper part. A small plate secured with a stud
holt keeps the springs Y in the sockets X. C' Care the keys on the loose ring W.
D D are the key ways on the sleeve O and E¹ E are the projections under
which the keys pass to prevent the loose ring coming up again. FF are the
openings in the ring W. through which the heels of the hooks project thus
keeping the said ring in position. G Gare the holes in the ring W. to permit the
insertion of the pivot pins of the looks U.
HH are the channels having stiffening plates Priveted to the lower end to
receive the pivot pins of the jaws K L are the side plates riveted to and
connecting the channels H H and having bolted between them the stop M. At
the lower part are bolted the cheeks N' N which receive the axles of the multiple
purchase barrel. These checks are brought low down to prevent the crane chain L
from slipping off the roller A. O'O' are the stop or striking plates for the jaws K¹
to strike against when fully open. Small plates P P of equal thickness to the
stiffening plates are riveted on to the inside of the jaws to meet the stop
plates O
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I wish it understood that I
claim :-
1st. Circular excavator or bucket or dredge-bucket provided with a multiple
purchase barrel consisting of a roller for the crane chain and a spindle extending
from each side of the said roller through bearings in the frame and having
attached to it the chains for closing the bucket, substantially as herein before
described.
2nd. In a circular dredge-bucket the combination of the multiple purchase
barrel the guide roller and the frame substantially as described and as illustrated in
Figures 1 to 3 or in Figures 4 and 5 of the accompanying drawings.
3rd. The modification of the circular dredge-bucket wherein I employ two guide-
rollers or sheaves, in place of the multiple purchase barrel, enclosed in a case
substantially as described and as illustrated in Figures 8 and 9 of the accompanying
drawings.
4th. In a circular dredge-bucket the employment of jaws the arms of which have
solid steel points formed thereon substantially as and for the purpose above
specified.
5th. In a dredge-bucket of square or clam shell pattern a multiple purchase
barrel of the kind above described placed in the frame with its axles at right
angles to the axles of the pivots of the jaws substantially as described.
6th. In a dredge-bucket of square or claim shell pattern the combination of the
multiple purchase barrel, the guide rollers and the frame substantially as described
and as illustrated in Figures 10, 11 & 14, of the accompanying drawing.
7th. In a dredge-bucket of either the circular or the square pattern, the com-

page_text: bination of the parts forming the sliding collar, substantially as described and as
illustrated in Figures 11 to 13 of the accompanying drawings for the purposes
above specified.
Dated this 22nd day of November 1890.
S. MANTHORP COCKBURN.