METHOD OF WORKING SELF-ACTING GRAPPLE BUCKETS AND FORKS
Year: 1877

page_text: LETTERS PATENT to William Dent Priestman, of Kingston-upon-Hull, in the
"IMPROVEMENTS IN THE
County of York, Engineer, for the Invention of
METHOD OF WORKING SELF-ACTING GRAPPLE BUCKETS AND FORKS."
Sealed the 18th December 1877, and dated the 13th October 1877.
PROVISIONAL SPECIFICATION left by the said William Dent Priestman at
the Office of the Commissioners of Patents on the 13th October 1877.
WILLIAM DENT PRIESTMAN, of Kingston-upon-Hull, in the County of York,
Engineer. "IMPROVEMENTS IN THE METHOD OF WORKING SELF-ACTING GRAPPLE
BUCKETS AND FORKS."
The object of this Invention is to facilitate the working of self-acting grapple
buckets or forks, whether such grapple buckets or forks be used with cranes,
winches, or crabs of the ordinary type, and hydraulic types as at present in use, or
in connection with a certain double-barrelled crane or winch, for which we obtained
Letters Patent on the 29 March 1877, No. 1243.
Self-acting grapple buckets or forks are used for automatically grappling material,
and then elevating it to certain heights, and afterwards depositing the material
directly from the dipper to the right or left, or any other position that may be
required.
În carrying out this operation, two chains or their equivalent are used, one being
the lifting chain, and the other the opening or discharging chain, which latter when
bauled upon causes the bucket or fork to open and discharge its contents.
This Invention consists in the application of sheaves or pulleys in the inverted order
of the ordinary block and pulley connected directly or indirectly with the piston or
piston rod of hydraulic, steam, or other motive-power cylinders, for the purpose of
multiplying the stroke of such pistons, and so increasing the length of chain or its
equivalent, which can be gathered in by a single stroke of a piston or piston rod,
and the use of such multiplied stroke to the working of automatic lifting
grapple buckets or forks.

page_text: In application two motive cylinders may be used, placed side by side, or in other
convenient manner.
The chain from the sheaves of the piston rods of one cylinder being the lifting
chain, and the chain from the sheaves of the other cylinder being the discharging
chain, the number and size of sheaves I arrange in accordance with the length of
stroke of the motive piston, and with the depth to which the grapple bucket or
fork is required to travel.
The working of my Invention may be thus described :-Upon the raising of the
grapple bucket or fork by the lifting cylinder and chain, the discharging cylinder
takes in the slack of the discharging chain. To empty the bucket or fork, the
discharging cylinder piston is stopped by shutting off the water supply in case of it
being a hydraulic motor, or by a break in case of it being a steam motor, and by
lowering or slacking the lifting chain, the discharging chain takes the weight of the
bucket or fork and its contents, causing the same to open and empty. Both chains
are then slacked, and the bucket or fork lowers down for another lift.
I would state that I am aware that the use of sheaves or pulleys for the purpose
of multiplying the extent of motion of a piston and piston rod is not new, such
having been patented by W. G. Armstrong in 1846, Patent No. 11319;
but my
Invention consists in the peculiar application of this arrangement in duplicate
working independently for actuating the lifting and discharging chains of automatic
grapple buckets or forks, or the single application for working the discharging chain
of self-acting grapple buckets or forks, in combination with any known description
of crane, winch, or crab, or other hoisting mechanism for working the lifting chain of
self-acting grapple buckets or forks.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Dent Priestman in the Great Seal Patent Office on the
28th March 1878.
WILLIAM DENT PRIESTMAN, of Kingston-upon-Hull, in the County of York,
Engineer. "IMPROVEMENTS IN THE METHOD OF WORKING SELF-ACTING GRAPPLE
BUCKETS AND FORKS."
The object of this Invention is to facilitate the working of self-acting grapple
buckets or forks, whether such grapple buckets or forks be used with cranes,
winches, or crabs of the ordinary type, and hydraulic types, as at present in use, or
in connection with a certain double-barrel crane or winch, for which Letters Patent
have been obtained on 29th March 1877, No. 1243.
Self-acting grapple buckets or forks are used for automatically grappling material,
and then elevating it to certain heights, and afterwards depositing the material
directly from the dipper to the right or to the left, or to any other position that may
be required.
In carrying out this operation, two chains or their equivalent are used, one being
the lifting chain and the other the opening or discharging chain, which latter, when.
hauled upon, causes the bucket or fork to open and discharge its contents.
This Invention consists in the application of sheaves or pulleys in the inverted order
of the ordinary block and pulley connected directly or indirectly with the piston or
piston rods of hydraulic, steam, or other motive-power cylinders for the purpose of
multiplying the stroke of such pistons, and so increasing the length of chain or its
equivalent, which can be gathered in by a single stroke of a piston or piston rod,
and the use of such multiplied stroke to the working of automatic lifting grapple
buckets or forks.
In operation, two motive cylinders may be used, placed side by side, or in other
convenient manner.
The chain from the sheaves of the piston rod of one cylinder being the lifting
chain, and the chain from the sheaves of the piston rod of the other cylinder being
the discharging chain, the number and size of sheaves are arranged in accordance
with the length of stroke of the motive pistons, and with the depth to which the
grapple bucket or fork is required to travel.
The working of this Invention may be thus described:-Upon raising of the
grapple bucket or fork by the lifting cylinder and chain, the discharging cylinder
takes in the slack of the discharging chain. To empty the bucket or fork, the
discharging cylinder piston is stopped by shutting off the water supply in case of
it being a hydraulic motor, or by a break in case of it being a steam motor, and
by lowering or slacking the lifting chain, the discharging chain takes the weight of
the bucket or fork and its contents, causing the same to open and empty. Both
chains are then slacked, and the bucket or fork lowers down for another lift.
I would state that I am aware that the use of sheaves or pulleys, for the purpose
of multiplying the extent of motion of a piston and piston rod, is not new, such
having been patented by W. G. Armstrong in 1846, Patent No. 11319; but my
Invention consists in the peculiar application of this arrangement in duplicate,
working independently for actuating the lifting and discharging chains of automatic
buckets or forks, or the single application for working the discharging chain of self-
acting grapple buckets or forks, in combination with any known description of
crane, winch, or crab, or other hoisting mechanism for working the lifting chain of
self-acting grapple buckets, or forks, or skips, or by whatever other name they may
be designated.
That my Invention may be clearly understood, I have hereunto annexed a Sheet
of Drawings illustrative thereof marked with letters and figures of reference
corresponding with those in the following explanation.
•
In all the Figures the same letters of reference, so far as they are applicable to
the Figures, indicate the same or corresponding parts.

page_text: Figure 1 is a side elevation of a hydraulic crane with my improvements applied
thereto; Figure 2 is an end view of Figure 1.
Figure 3 is a front view of a self-acting grapple bucket; Figure 4 is an end view
of same.
Upon reference to the Drawings, it will be seen that A is the pillar of a hydraulic
crane; B, the jib of the crane, which is provided with two sheaves C, D; E is the
hydraulic cylinder and ram for working the lifting chain S. The hydraulic
cylinder and ram E are provided with sheaves F, F', to elongate the lift of the
chain S, and with an auxiliary ram G, which acts as a guide, and also by
which a small pressure is brought to bear, as an assistance to the ram E, during the
return stroke. This arrangement of crane is of ordinary description and arrange-
ment of parts, with the exception of the additional sheave D.
My Invention consists in the addition and application of the hydraulic cylinder
and ram H, which is fastened to the pillar A, and is provided with the multiplying
sheaves I, J, for elongating the lift and gathering in the chain T, which is led over
the sheeves K, K¹, and D, the gathering in of the chain T by the hydraulic ram H
corresponding with the gathering in of the chain S by the hydraulic ram E; the
chain S running over the sheaves L and C; the duplicate ram M and the pulleys N
are for turning the pillar of the crane.
That the working of my Invention may be thoroughly understood, I have shown
a self-acting grapple bucket at Figures 3 and 4, to the working of which, or its
equivalent, my Invention is particularly applicable.
The bucket is constructed of the scoops a, a³, which are pivoted at c, c², to the
bottom of the guides X. The bucket, when open, assumes the position shown in
dotted lines in Figure 3. This is effected by the links b and the cross head e being
pulled up by the guide X, as also shown in dotted lines Figure 3.
To perform the
necessary operation, two chains are used, namely, the main or lifting chain S, which
is attached to the fixed barrel d, and the discharging or opening chain T, which is
attached to the cross head e. The cross head e is connected by chains to the fixed
barrels f, f¹, on the same shaft as the barrel d:
In operation, as the chain S is wound or gathered in by the hydraulic ram E, so
the bucket closes by the cross head e being brought down the slide. After closing
the bucket, the further gathering in of the chain S lifts the bucket. The gathering
in of the chain T is effected by the cylinder and ram H. When the bucket, with
its load, is in the required position for discharging, the gathering in of the chains S
and T is stopped, and upon lowering the chain S, or further gathering in of the chain
T, the bucket opens and discharges its contents.
The arrangements of the chains S and T equally applies to grapple forks of like
construction to the bucket shown in the Drawings, also to the working of other
lifting forks, buckets, skips, or their equivalent.
3
Having now set forth the nature of my said Invention for improvements in the
method of working grapple buckets and forks, or skips, or their equivalent, and
shown a system, mode, or manner in or under which the same is or may be used or
practically carried into effect, I would have it understood that my Invention is
capable of various modifications with regard to the class of motive-power cylinders
and pistons used; also in the number of sheaves for gathering in the chain and
elongating the lift; I would also have it understood that my Invention is applicable
to other classes of cranes and winches than that shown in the Drawings, such as
steam cranes, or hand cranes, or other hoisting mechanism of any type; I would
also have it understood that my Invention is applicable to the working of all
buckets, forks, skips, diggers, or by whatever name they may be known that are
self-acting, or require to be opened, discharged, or kecked; but what I claim as
my Invention and secured to me by the herein-before in part recited Letters
Patent is,
First. The use and particular application of sheaves or pulleys connected directly
or indirectly with the piston or piston rods of hydraulic, steam, or other motive-
power cylinders (for the purpose of multiplying the stroke of such pistons, and so

page_text: increasing the length of chain or its equivalent, which can be gathered in by a single
stroke of the piston or piston rod) in duplicate working independently for actuating
the lifting and discharging chains of automatic grapple buckets, or their equivalent,
in manner such as shown at Figures 1 and 2 of the accompanying Drawings, or any
modification thereof.
-
Second. The use and application of a hydraulic or other motive-power cylinder,
the piston of which is provided directly or indirectly with sheaves or pulleys
for the purpose of multiplying the stroke of such piston, and so increasing the
length of chain or its equivalent, which can be gathered in by a single stroke of
the piston for working the discharging chain of automatic lifting buckets or their
equivalent, in combination with any known description of crane, winch, crab, or
other hoisting mechanism for working the lifting chain of automatic grapple
buckets or their equivalent.
In witness whereof, I, the said William Dent Priestman, have hereunto set
my hand and seal, this Sixteenth day of March, in the year of our Lord
One thousand eight hundred and seventy-eight.
WILLIAM DENT (Ls.) PRIESTMAN.