IMPROVEMENTS IN REVERSING GEAR OF LOCOMOTIVE, MARINE, AND OTHER ENGINES."
Year: 1881

page_text: LETTERS PATENT to George Pearson Renshaw, of the Town and County of
the Town of Nottingham, for an Invention of "IMPROVEMENTS IN REVERSING
GEAR OF LOCOMOTIVE, MARINE, AND OTHER ENGINES."
PROVISIONAL SPECIFICATION left by the said George Pearson Renshaw at
the Office of the Commissioners of Patents on the 27th June 1881.
GEORGE PEARSON RENSHAW, of the Town and County of the Town of
Nottingham. "IMPROVEMENTS IN REVERSING GEAR OF LOCOMOTIVE, MARINE,
AND OTHER ENGINES."
Instead of employing two excentrics I obtain the forward motion in the usual
way, and the backward motion by means of connecting links and levers from the
same excentric sheave to reverse the engine. The one sheave by means of a
connecting link and hand lever is caused to partially revolve on the excentric, the
sheave being connected by other links and levers to the backward and forward
valves, the position of the hand lever thus opening or closing one or other of the
valves.
By such means I not only simplify the valve gearing by using one excentric
instead of two, but within the limits of the gauge I obtain more space for the
crank axle and other bearings.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said George Pearson Renshaw in the Great Seal Patent Office on the
21st December 1881.
GEORGE PEARSON RENSHAW, of the Town and County of the Town of
Nottingham. "IMPROVEMENTS IN REVERSING GEAR OF LOCOMOTIVE, MARINE,
AND OTHER ENGINES."
Instead of employing two excentrics I obtain the forward motion in the usual
way, and the backward motion by means of connecting links and levers from the
same excentric sheave.
The one sheave ring by means of a connecting link and
hand lever is caused to partially revolve on the excentric, the sheave being
connected by other links and levers to the backward and forward valves, the
position of the hand lever thus opening or closing one or other of the valves to
reverse the engine. By such means I not only simplify the valve gearing by using
one excentric instead of two, but within the limits of the gauge I obtain more
space for the crank axle and other bearings.
The object of my Invention, which is more particularly applicable to engines
working in pairs in either direction of revolution, such as locomotives and marine
screw engines, is to simplify and render more compact the valve motion for
actuating the slide valves of such engines by rendering unnecessary the use of the
four excentrics now used in such engines, namely, two for the forward and two
for the backward motion, and in place thereof requiring but one excentric for
each section of the engine, two in all, thus gaining increased surface for frictional
hearings
Figure 1 is a side view of my improved reversing gear applied to a pair of engines
working in concert, say as an ordinary railway locomotive.
Figures 2, 24, 3, and 4 are types of link motions, severally referred to
hereafter.
Referring to Figure 1 A is the cranked axle ; B, the fore excentric, giving motion
forward to, say, the right hand engine; C, the back excentric, giving motion
backwards to, say, the left hand engine; then as the cranks are (as usual) at right
angles it follows that a link F and lever H moved at a suitable angle from the
forward excentric B will serve to actuate the upper end of the link K, and in like
manner a link G deriving its motion at a suitable angle from the excentric C will
serve to actuate through the lower end of the link L the B engine for its back gear
motion through the link G and lever I.
Thus it will be evident that the details may be altered in position or construction
without affecting the general principle of my Invention.
For example, the slide valves may be placed either between the cylinders as
usual, or above, underneath, on the outside, or on the quarters of the said cylinders;
the link motion may be either of the shifting or stationary type, as shewn at
Figure 2, or straight link type, as shewn at Figure 24.
Or the link motion may be so arranged that the excentric rods are in the
downward position for the forward gear, and in the upward for the back gear, as
usual; or the back rod may be arranged to counter-balance the fore rod, as shewn
at Figure 3; or a simple crank pin at each end of the crank axle in locomotives;
or a return crank may be substituted for the excentric sheaves in locomotive
engines, as shewn at Figure 4.
The reversing motion may be under the control of a hand lever worked by the
engine man from the platform of a locomotive, as usual, or a screw motion as
sometimes now used may be substituted for the hand lever.

page_text: Having thus described the nature of my said Invention, and the manner of
performing the same, I declare that I claim for the improved reversing gear
constructed as herein before described and illustrated in the Drawings annexed.
In witness whereof, I, the said George Pearson Renshaw, have hereunto set
my hand and seal, this Twentieth day of December, in the year of our
Lord One thousand eight hundred and eighty one.
Witness,
H. W. GOUGH, C.E.,
Nottingham.