IMPROVEMENTS IN BALANCED SLIDE VALVES
Year: 1880

page_text: LETTERS PATENT to Edgar Robinson, of Columbus, in the County of Franklyn,
and State of Ohio, United States of North America, for the Invention
of "IMPROVEMENTS IN BALANCED SLIDE VALVES."
COMPLETE SPECIFICATION filed by the said Edgar Robinson at the Office
of the Commissioners of Patents on the 22nd January 1880.
EDGAR ROBINSON, of Columbus, State of Ohio, and United States of North
America. "IMPROVEMENTS IN BALANCED SLIDE VALVES."
My Invention consists in the construction and novel arrangement in connection
with a slide valve and lifting stem or stems indirectly connected therewith of a
piston operated by the steam in the valve chest, and adjustable lever connections
located outside the valve chest and arranged to operate in connection with the
outer ends of the piston rod, and lifting stem or stems as hereinafter fully described.
In the accompanying Drawings A represents the body or casing of any steam
chest located in any suitable manner in connection with its cylinder A', and B is
the slide valve, B¹ the ports of the cylinder and their construction and arrangement
may be in accordance with any plan as my Invention is not limited in the precise
form shown. Attached firmly in any manner to the valve B is a metallic surface C
which may or may not be made in rack-form as will hereinafter more fully appear.
This surface C is designed to act as a bearing for two or more anti-fricton rollers D
which are adapted to move in the space between the surface C and a stationary
surface E, the form of which corresponds to that of the valve surface C. These
rollers serve to facilitate the movement of the latter surface and if the surfaces C
and E be made in rack form the rollers should be ribbed or fluted to correspond
therewith. When thus constructed the rollers D may be more readily secured in
proper position and relation with each other and the adjacent parts, than if made
smooth and operating against smooth surfaces.
Either form however may be adopted, as my Invention is not confined in this
respect, but the rack form is preferable. In this construction the fluted rollers are
provided with smooth cylindrical ends which engage or bear on smooth side surfaces
arranged on the ends of the ribs of the racks, and corresponding in superficial
position with the pitch-line of the respective racks, the object being to effect the
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page_text: bearing of these smooth roller surfaces on said side surfaces, while the rack arrange-
ment serves to keep said parts in proper relative position.
The stationary surface or plate E supports a stem E' which passes up through
a slot a in the moving surface or plate C, and through the case A, its upper
end being connected to its lever E, as shown in the Drawings or in any other
suitable manner. It is apparent that if the stem E¹ be lifted it will tend to raise
the valve B from its seat and relieve the pressure of said valve thereon, while at
the same time the valve is allowed free movement of reciprocation through the
agency of the surfaces C, E, and the anti-friction rollers above referred to. In order
to effect and govern the lifting of the valve B the steam in the valve chest is
utilized to raise the piston F in the auxiliary cylinder F, which may be raised
from the valve-chest cover as shown and which has steam connection with the
valve chest. Attached to the piston stem F' of the piston F, or resting upon the
upper end thereof, is an arm or bar G or its equivalent which is pivoted at its
outer end to a suitable post or lug on the steam-chest while its inner end is under
the lever E of the stem E¹. On this arm or lever is arranged a movable and ad-
justable block G¹ which is connected with said arm or lever by dove tail side
flanges or otherwise, and is provided with two anti-friction rollers a¹ whereof_the
lower resta on said lever G while the upper roller bears on the lower one and at
the same time supports the lever E³. By means of a small lug or other fastening
a wire or rod connected to this block C serves to enable the engineer to adjust its
position when necessary. As the block or bearing G' is moved towards or from
the fulcrum L of the lever E³, so will the lifting power of the steam on the
piston F be diminshed or increased. The point of adjustment of the block or rest
G should be such that the lifting power of the steam against the piston F will be
sufficient to almost lift the valve B from its seat against the pressure of the steam
within the chest. Sometimes two lifting stems for the valve may be employed
and two adjustable rests used in connection therewith, the piston being placed
between the lifting stems, and generally the mechanical construction of the levers
and bearing G¹ may be varied without departing from my Invention, which consists
broadly in any device employing the auxiliary cylinder and piston F, and any ad-
justable connection between said cylinder and piston and the valve B, whereby the
pressure of steam acting through said cylinder and piston will be sufficient to lift
the valve or nearly lift the same against the pressure, of steam above it.
When adapted for use on locomotives I prefer that the adjusting apparatus which
regulates the leverage between the piston F and valve B should be susceptible of
manipulation and control from the engineer's cab by means of any suitable rod
connection therewith, so that the slide valve will be at all times and under any
circumstances under the ready control of the engineer. The principal advantages
attained through this Invention are first a practical avoidance of wearing friction
between the slide valve and its seat, and consequently a greater ease and facility
of movement, and a saving of strain and wear upon the valve-rod and all joints and
parts therewith connected. which can therefore be made of lighter material with a
corresponding enconomy of weight and expense; and secondly, owing to the great
diminution of friction and strain that the power of the engine is enabled to be
more fully and directly applied in motive force. I have found by practical ex-
periment with this Invention in use upon locomotives that with the same expenditure
of steam and fuel more cars could be pulled than could be done with the same
engine without my appliances.
H is a spring or its equivalent which exerts an upward pressure upon the stem
F when the steam is shut off as in the case of a locomotive on a down grade. By
means of this spring at such a time the valve B is not permitted to rest injuriously
upon its seat, and the grinding and wearing action which would otherwise occur is
avoided. This spring if desired may be made adjustable so that any desired lifting
force may be exerted thereby.
Having now described my Invention and the manner in which the same may be
carried into effect what I claim and desire to secure by Letters Patent is, -

page_text: 1st. The method and means herein before described and shown in the accompanying
Drawings, or their equivalent, for balancing slide valves, which consists essentially
in devices adapted to raise the slide valve on its seat against the pressure of the
steam in the valve chest.
2d. The construction and arrangement of mechanism employed to balance slide
valves or its equivalent substantially as hereinbefore described and shown by the
accompanying Drawings.
3d. The means employed and the arrangement of mechanism as described or their
equivalent for adjusting the hight to which the slide valve shall be lifted on its seat
as set forth.
4th. The devices or means employed or their equivalent for lifting the slide valve
on its seat when the steam is cut off from the valve chest substantially as shown
and described.
In witness whereof, I, the said Edgar Robinson, have hereunto set my hand
and affixed my seal, this Twenty second day of January, in the year of our
Lord One thousand eight hundred and eighty.
EDGAR ROBINSON. (L.S.)