An Improved Valve for Controlling the Inflow and Discharge of Hydraulic Pressure to and from Lift and other Cylinders.
Year: 1891

page_text: COMPLETE SPECIFICATION.
An Improved Valve for Controlling the Inflow and Discharge of
Hydraulic Pressure to and from Lift and other Cylinders.
We, HUGH JAMES GWYNNE of Moray Street, South Melbourne, in the Colony
of Victoria, Engineer, and GEORGE EMSLIE FOWLER of 325 Collins Street,
Melbourne in Victoria, as aforesaid. Engineer, 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:-
Our invention is constructed of two main parts; first a cylindrical slide rod or
valve having two distinct ports or passages in it and each port having perforations
at both its ends and second a casing or valve box for such slide rod having three
branches on it one for receiving the hydraulic pressure supply from main, another
for connection to the lift cylinder and the other for leading off the discharge from
cylinder. The casing is also furnished with three leathers and with end stuffing
boxes and glands through which the valve works, each end of the valve being
exposed to the atmosphere and connected to the rope or medium that is operated
from cage.
Our valve rod is practically held in equilibrium by its being so
constructed that the hydraulic supply at all times exerts an uniform pressure over
all parts to which it is admitted.
The invention will be best understood by describing it by reference to the
accompanying sheet of drawings in which,
Fig. 1 is a side view of it with the valve rod in its lowermost position and
Figs. 2 and 3 are longitudinal sections through centre of valve the former
shewing the valve rod in position for passing a full supply to cylinder and the latter
with the valve rod in position to cut off the supply thereto.
Fig. 4 is a section on line x, x, Fig. 2.
A is the valve rod having a long narrow passage or exhaust port A' formed in
it that communicates with exterior by small holes or perforations a at each of its
ends. A is a shorter passage or supply port also cominunicating with exterior by
small holes or perforations a' at each end, these ports are separated from each
other by the central metal division A*. B, B1, B2 and B are the four parts
forming the casing or valve box, B has a branch C on it leading to lift or other
cylinders, B has a branch C₁ for connection to hydraulic pressure supply main and
B³ has the discharge branch C on it. D, D are screw glands at top and bottom
of valve box for adjusting the packing around the valve rod.
In the joint
between B' and B, and B' and B', are suitable recesses for packing leathers E, E,
that fit closely upon valve rod A and it will be observed that these leathers are
arranged to be pressed close upon the valve rod by the pressure entering branch
pipe Č¹ from main, F are bolts securing parts B, B', B', and B' together. E' is a
leather arranged as shewn in a suitable recess in joint between B' and B'.
The mode of operation of the valve will be understood by the sectional drawings
Fig. 2 shewing the valve in position to allow of the hydraulic pressure passing to
lift cylinder, the supply entering branch C¹ passes to chamber of casing B₁ and
from thence through lower perforations a¹ to port or passage A² in valve rod and
out through upper perforations a' to chamber of casing B from whence it passes to
lift cylinder through branch C. It must also be observed that the pressure within
casing B has access also to casing B2 by way of exhaust port A¹ and perforations a
consequently as before stated the valve is held in a state of equilibrium by the
pressure being equal on both its ends. Now to cut off the supply to lift cylinder,
valve rod A is pulled down low enough for the perforations a¹ of port A' to be
below bottom of chamber B or within chamber B as shewu in Fig. 3 again to
place the valve rod in position to allow the hydraulic pressure to discharge from

page_text: lift cylinder the valve rod is lowered still further or until the lower perforations
of port A' are within the casing B' when the liquid pressure will flow thereinto
from chamber B through exhaust port A' and perforations a.
By constructing the valve rod with two distinct ports or passage ways com-
municated with by small perforations the number of holes or total area of the
latter can be adjusted to a nicety while the area at each end of both ports may be
varied to suit requirements also by having small perforations the leathers are not
so liable to be injured by the passage of the valve rod through them. Again
should the pressure in cylinder at any time become momentarily greater than the
pressure in main by our construction of valve and arrangement of leathers it
immediately exerts its force direct upon pressure in main and equalizes the pressure
from cylinder passing from chambers at top and bottom of leathers E, E, through
them and into the main.
Our invention may be used for hydraulic cranes or hoists as well as lift
cylinders.
Having now particularly described and ascertained the nature of said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
1. A cylindrical slide rod or valve having ports or passages such as A', A' in
it each with small perforations at their ends as herein described and as illustrated
in our drawings.
2. A valve casing or box made up in four parts furnished with three branches
and three leathers and top and bottom stuffing boxes as herein described and as
illustrated in our drawings.
3. The combination of above claimed slide rod and valve box together forming
our improved valve for controlling the inflow and discharge of hydraulic pressure
to and from lift and other cylinders as herein described and as illustrated in our
drawings.
Dated this 21st day of September 1891.
TT T CWVNND
H. J. GWYNNE,
By L. W., per F. B.
G. E. FOWLER,
By L. W., per F. B.