Year: 1892

page_text: Date of Application, 24th Nov., 1892
Complete Specification Left, 23rd Aug., 1893-Accepted, 30th Sept., 1893

page_text: The exhaust can be arranged in such a way that while one ram is pressing, the
other is exhausting, and vice versa. Thus it is not necessary to have a constant
pressure on the return ram as is usually done, the exhaust being open to the
return ram when the main ram is being acted upon by the pressure.
The advantages of this valve are
I. The valve is absolutely tight, and does not permit cranes and hoists to cree
when not in use, as most valves usually do.
II. The pressure being constant on the back of the valve, the packing is not
disturbed as is the case in plug cocks, where the pressure acts when open on
the nose of the plug, pressing the plug back against the packing, and being
alternately open and shut many times daily, causing a leakage, and requiring
attention at short intervals. In the case of the disc valve, re-packing is required
only at very long intervals.
III. The valve can be arranged to work with a very small travel of the handle-
less than a quarter turn of the disc between exhaust and pressure, being sufficient
to ensure a perfectly tight neutral position, between these two points.
IV. Being worked by a lever handle, and the valve perfectly balanced and easily
worked, the load can be started without jerks.
The same principle can be applied to relief valves, and safety. valves for
accumulators &c.
121 02nd dow of November 1892
COSSAR MACKENZIE.
COMPLETE
SPECIFICATION.
Improvements in Hydraulic Valves for Hydraulic Cranes, Hoists, and
all kinds of Hydraulic Machinery.
1, COSSAR MACKENZIE of Edinburgh Foundry Edinburgh, in the County of
Midlothian, North Britain, Ironfounder, 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 relates to a "disc" valve or cock for hydraulic cranes, hoists and
other hydraulic machinery, and has for its object to provide an hydraulic disc valve
with admission port or ports and exhaust port or ports which work in a more
efficient manner, and last longer than those at present in use, without requiring to
be re-packed, ground or faced.
My invention may be applied to either a three or four way valve, and consists of
a shallow cylinder the inside end of which is faced and provided with holes or ports
connecting with the pipes to the operating ram and exhaust. Inside the cylinder
is a flat disc mounted on the inner end of a spindle the front end of which passes
out through a suitably packed stuffing gland and is provided with an operating
handle or lever. As the disc is not so thick or deep as the cylinder, there is an
annular chamber or space between the back of the disc and the gland, into which 1
lead the pressure pipe, so as always to keep, the pressure on the back of the disc
constant, and so ensure of the valve being close and tight..
But in order that my said invention may be more readily understood, I will
describe a three way valve or cock, reference being made to the accompanying
drawings.
Figure 1 is a longitudinal section.
Figure 2 is an end view taken on line a. a. of Figure 1, showing the bottom of
the cylinder and valve seat.
Figures 3 and 4, are front and end views of the disc, and Figure 5 is a
longitudinal view of same, on line b. b. Figures 3 and 4.
Keterring to the said drawings, I employ a shallow cylinder A, which is provided
with the necessary means for connecting it with the pressure pipes, which operate
the ram, and with the exhaust pipes a¹, a², and a³. Inside the said cylinder A

page_text: I mount a disc B, which is provided or formed in one piece with a spindle C, the
front end of which passes through a tight fitting stuffing box and gland arrange--
ment D, (more particularly shown in Figure 1.) in front of which it is provided
with an operating handle or lever E. The back or inner end of said cylinder A is
ground so as to form the valve seat or face against which the ground face of the
disc B works; said disc B being formed of a less depth than the cylinder A so as
to: form or provide an annular chamber or space a around the back of the disc,.
and between the said disc and stuffing box, so as to permit of the pressure pipe a
being led therein and so cause a constant pressure to be exerted on the disc B and
thereby tend to keep the valve tight and so prevent it from leaking, or allowing
cranes, hoists or like machinery from creeping when not in use, also owing to the
pressure being constant on the back of the disc B, the packing of the stuffing box.
is not in any way disturbed, as is the case in plug cocks where the pressure acts.
when open on the nose of the plug and presses it back against the packing, so that.
every time the said plug valve is opened or shut the packing is disturbed and
thereby the frequent re-packing is required, whereas with my disc valve, re-packing
seldom requires to be done.
The action of the said valve is such that on the disc B being partially revolved,.
so as to take the position shown in Figure 1; the fluid under pressure passes from
the pressure pipe a³ and annular space a', through the port or opening 6 of the disc
to the supply pipe a² of the cylinder of the ram. After the ram has been actuated
sufficiently and the lever E partially revolved the port of the disc will be taken
away from the supply pipe a² and the one end of the exhaust port or passage F
will take its place, so as to permit of the fluid being exhausted from the ram's
cylinder, owing to the said port or passage F being preferably formed of a shape as.
shown in Figure 5, the end of which is formed in the centre of the disc B so as
always to be opposite the end of the exhaust pipe or opening a³ of the valve. Or
when desired to retain the ram in any particular position, the lever E is actuated
so as to bring a blank portion of the disc B opposite the mouth of the supply
pipe a² where it is retained owing to the constant pressure acting on the back of
said disc B. The said supply and exhaust ports baud F of the disc B may be so.
proportioned and arranged as to leave a tight neutral portion or blank between
them without necesitating the disc being revolved more than a quarter of a circle
from the pressure inlet to the exhaust outlet.
When applying my invention to four way valve or cock as used for a double
acting ram or for two alternate rams, I provide or form the cylinder and the disc
with two supply ports or passages, in lieu of one, preferably arranged one on either
side of the exhaust port and connected to the cylinders of the rams or to each end
of the cylinder in the case of a double acting ram. The exhaust may be arranged
in such a manner that while the one ram is pressing the other would be exhausting
and vice versa, thus obviating the necesity of having a constant pressure on the
return ram, as is usually the case, owing to the exhaust being open to the return
ram when the main ram is being acted upon by the pressure.
The exhaust ports or passages in the disc may if desired be simply grooves or
slots in lieu of passages as shown in Figure 5, and my invention may be applied
to relief and safety valves for accumulators and the like. In some cases when
desired I may provide means whereby the disc may be slightly withdrawn from
the valve seat so as to permit of the faces being washed or scoured by the
pressure water passing between them, that is to say I form the end of stuffing
gland with an external screwed projection d, and on which is screwed a uut d²;
said nut acting against a shoulder c formed on the spindle C, in such a manner that
on the nut being unscrewed, the spindle and disc may be slightly withdrawo.
The whole arrangement thus forming an effective and simple hydraulic valve
which is perfectly balanced and easily worked, owing to the motion of the valve
being rotary; and the pressure being on the back, the water does not require to be
displaced when operating the valve. Also the ram or rams may be started or
stopped without any jerky effects.

page_text: Having now particularly described, and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1st. The arrangement and construction of the circular disc and cylinder valve,
having admission and exhaust ports, for hydraulic machinery, whereby the pressure
is constant behind the disc for the purpose of keeping the valve tight, and enabling
the disc to grind its own seat so as to save repair, substantially as hereinbefore
described and shown in the accompanying drawings.
2nd. In hydraulic valves, the circular revolving disc B, mounted within the
cylinder A and provided with ports or openings b, F, for both pressure and exhaust,
substantially as and for the purposes hereinbefore described, and shown in the
accompanying drawings.
3rd. The general arrangement, construction and combination of the various
parts constituting my improved hydraulic valve for all kinds of hydraulic
machinery, substantially as hereinbefore described and shown in the accompanying
drawings.
Dated this 21st day of August 1893.
JOHNSONS,
115, St. Vincent Street, Glasgow, Applicant's Agents.