Improvements in Hydraulic Hoisting Apparatus.
Year: 1891

page_text: Date of Application, 8th Dec., 1891-Accepted, 5th Mar., 1892
COMPLETE SPECIFICATION.
Improvements in Hydraulic Hoisting Apparatus.
We, FREDERICK JAMES EASTMEAD, of Chatsworth, Church Place South,
Penarth, Engineer, and DAVID (CYNRIG) THOMAS, of Bronwydd, Llanishen,
near Cardiff, Hoisting Engineer, in the County of Glamorgan, 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:
This invention consists of the improvements in hydraulic hoisting apparatus
hereinafter set forth :-
Fig. 1. is a section through the apparatus on the line a b.
Fig. 2. is a sectional elevation.
Figs. 3, 4, and 5 represent varying positions of the ports in a three-way valve,
which is used to control the apparatus.
Inside a round cylinder A, which is closed at both ends by covers B and C, is a
smaller round cylinder D.
This inner cylinder D is fixed upon a shaft E, which is free to rotate in stuffing-
boxes in the covers B and C of the outer cylinder A. A winding drum F is fixed
upon that portion of the shaft E, which is outside of the cylinder A. In the
periphery of the inner cylinder D is a series of four radial grooves in each of
which is fitted a sliding piston blade G. The piston blades G each have_pro-
jections H, which fit into grooves J in the covers B and C. The grooves Jare
concentric with the cylinder A. The inner cylinder D and its shaft E are
concentric with each other, but are not concentric with the outer cylinder A. The
peripheries of the cylinders A and D meet at the point K. L is a pressure relief
valve communicating with the space between the cylinders A and D on each side of
the point K..
M is the supply pipe, N the exhaust, and O a pipe communicating with the
port P of the cylinder A. The port Q is also in communication with the supply
pipe M, and is always open to the supply. R is a three-way valve. S is a pipe,
which admits pressure from the supply into the interior of the cylinder D.
The action of the apparatus is as follows:-
:―
When the valve R is in the position shown in Fig. 3, the pipe O being open to
the exhaust N, the pressure acting through the port Q upon the piston blades G
one after the other forces them and the cylinder D to revolve around their respective
axes. Rotary notion is thus given to the shaft E and the winding drum F'in the
proper direction and the load is raised.
When the valve R is in the position shown in Fig. 4, the pressure acts through
the ports P and Q in opposite directions. The load, acting through the winding
drum F and shaft E, now causes the cylinder D and its piston blades G to revolve
in the direction opposite to that while raising the load, and accordingly descends
by its own weight.
In Fig. 5, the pipe O is cut off from both the supply and exhaust, and the load
is sustained by the pressure always acting through the open port Q on one, or other,
of the piston blades G.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. Hydraulic rotary hoisting apparatus in which radial piston blades G revolve
eccentrically around the axis of the winding shaft substantially as described.

page_text: 2. In hydraulic rotary hoisting apparatus as hereinbefore set forth the arrange-
ment of a three-way valve for controlling the supply and exhaust substantially as
described.
3. Hydraulic rotary hoisting apparatus substantially as described in the
drawings.
Dated this Fifth day of Decen ber 1891.
ber 1891.
FREDERICK JAMES EASTMEAD.
DAVID (CYNRIG) THOMAS.