IMPROVEMENTS IN HYDRAULIC CRANES OR APPARATUS FOR RAISING, HAULING, and LowERING WEIGHTS
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Bryan Johnson and Edward
Bayzand Ellington at the Office of the Commissioners of Patents,
with their Petition, on the 2nd March 1870.
We, BRYAN JOHNSON and EDWARD BAYZAND ELLINGTON, both of
the City of Chester, Engineers, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN HYDRAULIC CRANES OR APPARATUS FOR
RAISING, HAULING, and LowERING WEIGHTS," to be as follows:-
In the Provisional Specification of a Patent granted to us on the
25th Nov. 1869 (No. 3409) was described a manner of constructing
hydraulic cranes and apparatus for moving weights whereby variable
powers might be obtained without employing rams or pistons of varying
diameter.
According to our present Invention we effect this by means of
arrangements of apparatus such as are shown in the Drawings hereunto
annexed. In each of these Figures x represents a hydraulic cylinder,
and y a ram working in the same; the ram in each case has mounted
upon it a pulley marked a.

page_text: In the arrangement shewn at Diagram 1 a single chain is used; it is
passed over the pulley a, and one of its ends has attached to it the
pulley c; the other end of the chain is led over a guide pulley, then
over the sheave of the pulley c, and back again to another guide pulley
before it is led to the arm of the crane. In this arrangement the stroke
of the ram can either be multiplied twice or four times by locking the
pulley c or the chain at the point b; a third power can be obtained by
locking the chain and pulley at a, whilst b and c are both free.
In the arrangement shewn at Diagram 2 the chain which passes over
the pulley a is fixed at one end to the hydraulic cylinder, whilst the
-other-end-can-be-attached either to a pulley bor c, or to both at once.
If the chain be attached to c the pulley 6 will be locked in position by a
pin, upon which it can turn if the chain be attached to b; then c is
locked.
In the arrangement shown at Diagram 3 one end of the chain which
is passed over the pulley a is wound around a drum A, whilst the other
end of the chain is wound around a drum C of smaller diameter. Either
one or other of the drums A and C can be locked to prevent its turning,
whilst the other is made fast by a clutch with the drum B on which the
lifting rope or chain is wound.
In the arrangement shown at Diagram 4 the movement given to one
or other end of the chain may be several times greater than the stroke
of the ram.
In the arrangement shown at Diagram 5 the movement given to one
or other of the chains coiled around the drums A or C may be varied by
fixing or releasing either one or other of the pulleys 6 or c, or by locking
the pulley a whilst b and c are both free.
In order to turn the pillars of hydraulic cranes we employ a cylinder
in which works a piston fitted on each side with a piston rod which
passes out through a gland at one or other end of the cylinder. At the
end of each rod is carried a pulley, over which is led a chain, one end
of which is fixed to the cylinder, whilst the other end is first led around
the crane pillar, then over the pulley carried by the other piston rod,
and finally is also attached to the cylinder or other fixed point, and the
attachment is made so that the chain may be tightened when required.
By this means when the piston is moved in the cylinder the crane pillar
is turned.

page_text: An arrangement by which the movement given to the chain which is
wound upon the pillar or drum may be more than twice as great as that
given to each piston rod is shewn at Diagram 6. This arrangement is
also applicable for working drums around which a lifting rope or chain L
is wound or led, as is indicated by the Diagram. In this Diagram E
represents either the the pillar of a crane or a drum fast on the axis
of the larger drum F, around which the lifting chain L is passed. If
B and H are locked the highest power is obtained, if A and H are
locked the second power, and if B and C are locked the lowest power.
In the above arrangement two locking pins are required, but in the
arrangement shown at Diagram 7 but one locking pin is requisite to
lock the chain either at the point A or B by passing the locking pin
through suitable links provided for the purpose. When the chain is
locked at A the motion of the piston is doubled, but when the chain is
locked at B the chain D receives only the same motion as the piston, so
that the same pressure on the piston will lift twice the weight. By
varying the diameters E and F the lifting chain L can be worked at any
desired speed. To control the descent of the weights water from one end
of the hydraulic cylinder may be allowed to pass to the other end through
a suitable valve, the passage through which can be adjusted so that the
water is not allowed to run to waste as is usual.