Reversing-gear for Steam and other Engines.
Year: 1890

page_text: Date of Application, 27th Nov., 1890-Accepted, 21st Feb., 1891
COMPLETE SPECIFICATION.
Reversing-gear for Steam and other Engines.
I, WILLIAM THOMSON, of Elm Villa, Cloudshill, Saint George, near Bristol,
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 :-
This invention consists in mechanism, for substitution for the usual link motion,
for reversing steam and other engines and is specially applicable to horizontal and
vertical engines of the smaller class, actuated either by steam, compressed air or
water.
Under one arrangement, comprised in this invention, the eccentric whereby the
slide valve is reciprocated is loose on the driving shaft and has fixed to one side, or
cast in one piece with it, a bevel toothed-wheel also loosely centred on the driving
shaft and gearing with a bevel wheel loosely carried on a reversing lever.
Gearing with this latter bevel wheel and rigidly secured to the driving shaft is a
third bevel wheel. The reversing lever is connected, at the driving shaft end, to an
eye or socket loosely encircling the shaft between the two bevel wheels centred
thereon. The eccentric is moved round the driving shaft, and the direction of
driving controlled, by operating the lever accordingly about the shaft as a fulcrum,
the lever acting on the eccentric through the bevel gearing.
Under a second arrangement, in which the eccentric is still loose on the driving
shaft, spur gearing is substituted for bevel gearing, there being four toothed-wheels,
one of which is fixed to or cast in one piece with the eccentric, and gears with a
second which is rigidly centred at one end of a pin passed through the reversing
lever and free to turn therein. A third toothed-wheel is rigidly centred at the
other end of the said pin and gears with a fourth wheel having internal teeth. This
latter wheel is keyed or otherwise fixed on the driving shaft.
As in the arrangement first above described, the eccentric is moved around the
shaft to any desired position by operating the reversing lever accordingly. In both
arrangements the direction of driving is capable of being reversed either while the
engine is in motion or stationary.
Referring to the accompanying sheets of illustrative drawings,
Fig. 1 represents a part side elevation and part section of a horizontal steam-engine
fitted with reversing mechanism arranged in accordance with one method comprised
in this invention.
Fig. 2 represents a plan, partly sectional, of the same with the difference that; in
Fig. 1 the reversing lever a is shown in the position occupied by it when the
direction of the driving motion is forward as indicated in the drawing by an
arrow.
In Fig. 2 the lever occupies the position at which it stands when the engine is
reversed.
Fig. 3 is a side elevation, partly sectional, of Fig. 2.
Fixed to one side of the eccentric b is a bevel wheel c loose on the driving shafts
and gearing with a second bevel wheel d loosely centred on the reversing lever a
which is screwed into or otherwise fixed to an eye or socket f loosely encircling the
driving shaft s.
A third bevel wheel g fixed on the shaft s also gears with the wheel d. When
the reversing lever a, which works in a notched quadrant h, is moved about the
driving shafts, whether the engine be stationary or in motion, the eccentric ↳ is
moved round on the shaft through the train of bevel gearing c, d, g and the direction
of motion of the crank i determined accordingly.
At Figs. 4, 5 and 6 is illustrated a modification in which spur gearing is

page_text: m
substituted for bevel gearing. In this arrangement a spur-wheel k is fixed to or
cast in one piece with the eccentric b, both being loose on the driving shaft s.
Gearing with the wheel k is a pinion keyed or otherwise fixed on the spindle
passed through the lever a and free to rotate therein. At the opposite end of the
spindle m is a third toothed-wheel n keyed or otherwise fixed and gearing with the
internally-toothed wheel o keyed on the driving shaft s.
when the
At
As the lever a is raised or lowered about the shaft s, which it loosely encircles
at f, the eccentric b is moved round on the shaft through the train of toothed
gearing k, l, n, o, and the direction of rotation of the crank i is altered accordingly.
At Fig. 4 the reversing lever a is shewn in the position occupied by
motion of the engine is forward as indicated in the drawing by an arrow.
Figs. 5 and 6 the lever is shewn in the position it occupies when the engine is
reversed. The action is the same if the wheel o be fixed to the eccentric instead
of the wheel and the latter substituted for the wheel o, the spindle m being turned
so that the pinion is kept in gear with the spur wheel k and the pinion n with the
spur wheel o.
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
1. The means hereinbefore described for reversing steam, hydraulic or compressed
air engines, consisting of a train of bevel toothed-wheels such as c, d and g of
which e, loosely centred on the driving shaft, is fixed to an eccentric (also loose on
the shaft); d is loosely centred on the reversing lever, which latter works about
the driving shaft as a fulcrum; and g is keyed on the driving shaft and gears with d
at the opposite side to c, substantially as set forth with reference to Figs. 1, 2 and 3
of the accompanying drawings.
2. The modification hereinbefore described with reference to Figs. 4, 5 and 6 of
the accompanying drawings, in which the direction of motion of the engine is
altered by means of a train of spur wheels such as k, l, n, o, of which k loosely
centred on the driving shaft, is fixed to an eccentric (also loose on the shaft);
1, gearing with k, is fixed at one end of a spindle passed loosely through the
reversing lever (which latter works about the driving shaft as a fulcrum); n is
keyed at the other end of said spindle and gears with o which has internally pro-
jecting teeth and is keyed to the driving shaft, substantially as set forth.
3. The alternative arrangement in which the internally-toothed spur wheel o is
fixed to the eccentric, and the spur wheel k is substituted for o, the pinion on the
spindle m continuing to gear with the spur wheel and the pinion n with the spur
wheel o, as above set forth with reference to Figs. 4, 5 and 6 of the accompanying
drawings.
Dated this 26th day of November 1890
NICHOLAS WATTS,
Bristol Bank Buildings, Bristol, Agent.