Improvements in Gear for Working Slide-valves.
Year: 1890

page_text: Date of Application, 7th Mar., 1890-Accepted, 12th Apr., 1890
COMPLETE SPECIFICATION.
Improvements in Gear for Working Slide-valves.
We, EDWARD NAPIER GALLOWAY, and JOHN HENRY BECKWITH, both of Knott
Mill Iron Works, Manchester, in the County of Lancaster, Engineers, do bereby
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 relates to gear for working the slide valve of a fluid pressure engine
or pump from a reciprocating part such as the crosshead or other part moving in
correspondence with the piston as we shall explain referring to the accompanying
drawings which shew diagrammatically the arrangement and operation of gear according
to our invention.
Let A Figs. 1 and 1" represent the cylinder, B the piston rod and the slide rod of
an engine or pump, we link the slide rod C to one arm D of a bell crank lever, another
arm E of which carries a roller e engaged in a cam groove F formed in a piece G
attached to the cross head or piston rod and moving to and fro with it. Each end of
the groove F is inclined so that as the pisten approaches each extreme of its stroke the
incline acting on the roller e causes the arm E to move from the one side of the
groove to the other, and consequently tho arm D to move the slide rod C. In order
to ensure the completo movement of the movement of the roller e at each end of the
piston stroke we provide a third arm H to the lever D E and connect this arm by a
spring K to the reciprocating part G. As this part approaches each ends of its stroke
the spring K becomes strained, and by its strain on the arm H it causes the roller e to
pass along the incline at the end of the groove which has reached it as shown.in
Fig. 1. Instead of employing a spring K as shown in Fig. 1 pressure on a piston
may be applied as shown in Figs. 2 and 2ª to cause the roller e to complete its stroke
along the incline at each end of the groove F. For this purpose the piston rod M of
an oscillating cylinder N is linked to the reciprocating piece G and carries a roller m
which travels along two curved arms L L of the lever D E.
The piston rod M being always pressed upwards the roller m as it travels along the
arms LL' presses these arms alternately upwards thus causing the roller e to make
its full stroke from the one side of the groove F to the other.
Instead of applying the oscillating cylinder N with pressure always acting on the
one side of its piston as shewn in Figs. 2 and 2ª a separate fixed cylinder N may be
arranged as shewn in Figs. 3 and 3ª with its slide valve moved by a reducing lever P
from the reciprocating part G. In this case, the pressure on the piston of N being
alternated by the movement of the slide valve of N, acts in conjunction with the
lever DẸ in moving tho slide of A, or if the pressure on the piston of N is sufficient
of itself to move the slide of A, the groove F serves merely as a guide controlling the
movement of the lever D E. The grooved reciprocating part G, instead of making
the full stroke of the piston rod B, may be pivotted at R as shewn in Figs. 4 and 4*
and linked to the piston rod B so as to have a reduced stroke, its groove F being
shaped to suit the movement in a circular path.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what wo
claim is :-
1. For working the slide valve of an engine or pump, the combination of a part
reciprocating along with the piston and having a cam groove acting on a roller
mounted on the arm of a lever linked to the slide rod, substantially as herein described.
2. In combination with the slide rod lever and cam groove referred to in the
preceding claim, a spring or a roller pressed by the piston of a subsidiary cylinder and
acting on the lever as the cam groove approaches each end of its stroke, so as to

page_text: ensure the complete movement of the lever as determined by the cam groove,
substantially as described.
3. In combination with the slide rod lever and cam groove above referred to, a
subsidiary cylinder having its piston connected to the slide valve of the main cylinder
and having its own slide valve worked by the reciprocating part, substantially as
described.
Dated this 711 1
ABEL & IMRAY,
Agents for the Applicants.