An Improved System of Machinery for Transmitting Motion to the Valves of Reversing Steam Engines, and other Engines.
Year: 1897

page_text: Date of Application, 14th June, 1897-Accepted, 30th Oct.,
1897
An Improved System of Machinery for Transmitting Motion to the
Valves of Reversing Steam Engines, and other Engines.
WILLIAM LOWE 49 Cambridge Street Paddington, Sydney New South Wales
Australia "Mechanical 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 :-
My invention chiefly relates to steam engines that have a forward and backward
motion and consists of a system of connecting machinery, either, from an eccentric
on the crank-shaft, on to the valve-spindle, or, from the connecting-rod,
to the valve-spindle, or from the connecting-rod or coupling-rod of
on
is some
a Locomotive engine, on to the valve spindle, and, although there
difference in the construction of the machinery that takes its motion from an
eccentric, and, that which takes it from the connecting or coupling-rods the design
in each case is the same.
To an eccentric placed on the crank-shaft exactly opposite the crank-and which would
generally give motion equal to the lap and lead of the valve-an eccentric-strap is
connected, to this strap an eccentric-rod is connected which has two holes in it, the
center lines through both of these holes and the center line of the crank-shaft should be
parallel to each other, and the centers of the eccentric-strap and of the two holes in the
eccentric-rod should be in a straight line. The hole in the end of the eccentric-rod
nearest to the eccentric-strap has a pivot made to fit it, the ends of which project
into either a straight guide which would control it to move in a straight line, or into
the end of a radius link, the other end of this link being connected to a stationary pin
fastened to the bedplate, or to any other convenient part of the engine, this
radius link would control the pivot so that it would move in a curved line which
would vary according to the length of the link. To the other end of the eccentric-rod
one end of a radius link is connected by means of a pin which is made to fit firm in
one and movable in the other, this link is taken back alongside the eccentric-rod towards
the crankshaft, to connect to one end of a link, the other end of which is connected
to the valve-spindle. The other ends of the two links-one of which is connected
to the eccentric-rod and the other to the valve-spindle are connected together by a
pin which is inade a working fit in both and firmly fixed in a moving or slide-block,
this block when the eccentric is in motion, moves in a straight guide, this
straight guide is fitted to a bracket with bearings to take the ends of a screw,
screw is fitted to the guide to move it to the required position on either side of the
crank-shaft. When the engine is at rest the reversing-guide would be beside
the crank-shaft, when in motion it would be on either side of the crank-shaft according
to the direction of movement and speed required. If desired the screw could be
dispensed with and a lever could be used to move the reversing-guide, or the screw
and guide could be dispensed with and a lever and link substituted.
the
As it is expedient to keep the action of the valve good, and as the strain comes-
in this invention on the eccentric-strap about equal all round, it is necessary that
while the wear is taken up lengthwise it should also be taken up from side to side, to do
this, two double wedge shaped pieces can be fitted inside of the eccentric-strap one
on each side near to the bolts that hold the two halves of the eccentric-strap together,

page_text: as shown in the drawing, on the closing of the two halves of the strap to take up
the length wear, the wedge shaped pieces will be pressed inwards and thus take up
the width wear.
Reference is to be had to the accompanying drawing forming a part of this
specification, in which similar characters of reference indicate corresponding parts in
all the figures.
Figure 1. is a front elevation of the improvement as applied to a pair of
marine engines, one engine being in section.
Figures 2 and 3 are side elevations of part of the same.
Figure 4 is a plan view of bracket with reversing guide and connections.
Figure 5 is a side elevation of bracket with reversing guide and screw.
Figure 6 is a side elevation of eccentric-strap and rod.
Figure 7 is a side elevation of eccentric strap with wedge pieces.
The improved valve gear as illustrated in Figure 1. is applied to a pair of
marine engines each having the usual slide valve a. operating over the ports in the
cylinder b. Each slide valve a. is provided with the usual valve spindle c. pivotally
connected at its outer end with a pin d. held in the forked end of a link E. pivotally
connected at its lower end with a pin F. secured in a block G. held to slide vertically
in a guideway H. fitted to slide in a bracket I. (see Figures 4 and 5) attached to the
bedplate of the engine or other suitable stationary part. The guideway H. is
engaged by a screw J. having a hand wheel J. mounted to turn in the bearings I'.
so as to move the guideway H. to either side of the main driving shaft according to
the direction in which the engine is to run, or to move the said guideway into an
intermediate or middle position when the engine is at rest. On the pin F. previously
mentioned (Figure 1) is fulcrumed the link K. extending parallel to the link E. and
pivotally connected at its upper end by a pin L. with the free end of a rod N. of
an eccentric O. secured on the main driving shaft P. The rod N. is provided near
its strap with a pin Q. engaging a block R. fitted to slide vertically in a guideway S.
secured to the bedplate or other fixed part of the engine, the guideways H and S
standing parallel one to the other and the guideway S. extending in a plane passing
through the shaft P. and the valve spindle C. (See Figure 2). The eccentric strap N¹.
of the eccentric rod N. is preferably provided with movable side pieces N². (Figure 7)
for taking up wear, to insure the proper working of the eccentric.
The operation is as follows; When the block G. which is held to slide vertically in
the guideway H. is at one side of the shaft P. as shown in Figure 3. and the engine
is running the eccentric O. then imparts an upward and downward motion to the
rod N. which also swings laterally owing to the pivot pin Q. being controlled by the
guideway S. This motion of the rod N. causes the link K. to impart an up and
down sliding motion to the block G. which in turn imparts motion to the link E. and
valve spindle C. to shift the valve a. over the cylinder ports. Now by adjusting the
guideway H. in the bracket I. any desired amount of opening of port can be given
to the valve a. the lead being always equal, and when it is desired to reverse
the engines the operator turns the handle J¹. to cause the screw J. to move the
guideway H. to the other side of the shaft P. and by so doing the motion of
the engines will be reversed.
Having now particularly described and ascertained the nature of my said
Invention, and in what manner the same is to be performed, I declare that what I
claim is:
1. The principle of controlling a point in either an eccentric strap or an
eccentric rod when an eccentric is used to give motion to this machinery, or, of
controlling a point in a connecting rod that would act similar to the eccentric rod,
but would take its motion from a link connected to the connecting, or coupling rods
of engines, this link would have three holes through it, the hole at one end of it
would be connected to the connecting rod that would act similar to the eccentric rod,
the other end hole being connected to the connecting or coupling rods of engines,
and the intermediate hole would be connected to a link, the other end of which

page_text: would be connected to a stationary pin, or, the intermediate hole would be connected
to a block moving in a straight guide.
2. The system of connecting a link to the eccentric-rod and a link to the
valve-spindle and of connecting the other ends of these two links together to a
slide-block, and of connecting said slide-block to a straight reversing-guide, or, of
connecting the other ends of the links connected to the eccentric-rod and to the
valve-spindle, to one end of a radius link, the other end of which would be
connected to a lever on a waybar shaft.
3. The mode as described of taking up the wear the width way of the
eccentric-strap.