Improvements in or connected with Reversing Gear for Steam and other Engines.
Year: 1895

page_text: Date of Application, 12th Aug., 1895-Accepted, 14th Sept., 1895
COMPLETE SPECIFICATION.
Improvements in or connected with Reversing Gear for Steam
and other Engines.
We, WILLIAM FOSTER AND COMPANY, LIMITED, and SAM STARKEY,
Engineers, all of Wellington Foundry, in the City of Lincoln, 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 relates to improvements in or connected with reversing gear for
steam and other engines.
The form of reversing gear generally employed is the well known link motion
but this mechanism is exceedingly complex and the wear and tear thereof is very
considerable necessitating frequent repairs.
Now, the object of the present invention is to obtain a simple means whereby
the direction of motion of the engine may he readily reversed.
In carrying the invention into effect, a single eccentric is employed but in lieu
of being directly fixed upon the crank shaft as heretofore it is mounted loosely
thereon and indirectly fixed therewith in the following manner.
The loose eccentric is formed with a central oblong aperture therein to receive
the crank shaft and at one side of the eccentric and fixed upon the crank shaft is
a concentric driving disc provided in its inner face with a groove which extends
completely across the same and upon the adjacent face of the eccentric are
provided co-acting feathers or projections which fit the groove of the driving disc
and are arranged parallel with the oblong aperture of the eccentric.
The eccentric which actuates the slide valve by means of the usual strap and
rod is by the means above described caused to rotate with the crank shaft
whilst at the same time it is adapted to be moved across the axis of the shaft in
either direction in order to reverse the engine.
In order to move the eccentric in this manner across the axis of the shaft a
concentric reversing disc is loosely mounted upon the crank shaft at the side of
the eccentric farthest from the driving disc and this reversing disc is held up
to its work by any suitable means such as a collar fixed upon the crank shaft.
In the inner face of the reversing disc is formed an annular groove arranged
eccentrically to the axis of the crank shaft whilst in the adjacent face of the
eccentric is fixed a pin upon which loosely engages a hole in a block shaped to an
are and fitting with nicety the eccentric groove of the reversing disc and thus by
turning the reversing disc upon the crank shaft the eccentric will through the
eccentric groove and block and pin be caused to move across the axis of the crank
shaft in order to reverse the direction of motion of the engine.
The reversing disc may be rotated by means of levers worked by hand or by
other suitable means whilst a stop is provided in the eccentric groove thereof to
limit the motion of the parts.
It will be obvious that the arrangement of parts connecting the driving disc
and the eccentric may be reversed, that is to say, the groove may be formed in
the eccentric and the ribs or projections upon the driving disc.
And, in order that the said invention may be more clearly understood and
readily carried into effect, we will proceed aided by the accompanying drawings
more fully to describe the same.

page_text: Figure 1. is a front elevation of a portion of a crank shaft having the present
invention applied thereto.
Figure 2, is an end view thereof but. with the reversing disc removed.
Figure 3, is a similar view but with the reversing disc and eccentric removed.
Figure 4, is an inside face view of the reversing disc and showing the sliding
block in mid-position in the eccentric groove.
Figure 5. is an inside face view of the eccentric showing more particularly the
arrangement of the feathers or projections.
In the several figures, in which like parts are indicated by similar letters of
reference, the eccentric strap is omitted for the sake of clearness.
a represents the crank shaft, 6 represents the eccentric, c represents the driving
disc and d represents the reversing disc.
The eccentric b. which is loosely mounted upon the crank shaft a. is formed with
an oblong aperture therein to receive the same as shown at Figures 2, and 5,
and at one side of the eccentric b. and fixed upon the crank shaft a. is the con-
centric driving disc c. provided in its inner face with a groove c¹ which extends
completely across the same and upon the adjacent face of the eccentric b. are
provided co-acting feathers or projections as shown at Figures 1. and 5, which
fit the groove c¹ of the driving disc c. and are arranged parallel with the oblong
aperture of the eccentric b.
The eccentric b. which actuates the slide valve by means of the usual strap and
rod (not shown) is by the device above described caused to rotate with the crank
shaft a. whilst at the same time it is adapted to be moved across the axis of the
shaft a. in either direction as indicated by the dotted lines in Figure 2. in order to
reverse the direction of motion of the engine.
In order to move the eccentric b. in this manner across the axis of the shaft a.
the concentric reversing disc d. is employed which is loosely mounted upon the
crank shaft a. at the side of the eccentric . farthest from the driving disc c. and
this reversing disc d. is held up to its work by means of a toothed wheel e. fixed
upon the crank shaft a. and the object of which wheel is hereinafter explained.
In the inner face of the reversing disc d is formed an annular groove d' arranged
eccentrically to the axis of the crank shaft a. as shown at Figure 4. whilst in the
adjacent face of the eccentric b. is fixed a pin which loosely engages a hole d³ in
a block & shaped to an arc so as to fit with nicety the eccentric groove d¹ of the
reversing disc d.
By turning the reversing disc d. upon the crank shaft a. the eccentric b. will
through the eccentric groove d' and block d³ of the reversing disc d. and pin of
the eccentric b. be caused to move across the axis of the crank shaft a. and within
the limits of the oblong aperture and thereby reverse the direction of motion
of the engine.
The eccentric groove d' of the reversing disc d. is filled in for part of its circum-
ference with a plate d the ends of which form stops to engage the block d' as
indicated by the dotted lines in Figure 4, and thus limit the rotary motion of the
disc d. with relation to the eccentric b.
The reversing disc d. may be rotated to move the eccentric b. by any suitable
means, but it is preferred to employ for that purpose the turning mechanism shown
and described in the Specification of Letters Patent granted to Sam Starkey dated
the 26th day of May 1879 No. 2092 and for this purpose the boss of the reversing
disc d. is formed with a toothed wheel d' and this and the toothed wheel e.
correspond with the wheels "L. B." shown and described in Starkey's said
Specification.
It will be evident that the arrangement of parts connecting the driving disc c.
and the eccentric b. may be reversed, that is to say, the groove c' may be formed
in the cccentric b. and the feathers or projections may be formed on the driving
disc c.

page_text: It will also be understood that although the invention is hereinbefore shown an
described in connection with a crank shaft it can usefully be applied to any other
revolving shaft of the engine.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. In combination with revolving shaft of an engine, an eccentric mounted
loosely with relation to the shaft and with capability of movement across the axis
thereof, means for communicating the rotary movement of shaft to the eccentric
whilst permitting the cross movement of the latter, means for moving the
eccentric across the axis of the shaft to the desired extent and there retaining
it and means for communicating motion of the eccentric to the slide or other
valve of the engine, substantially as herein shown and described and for the
purpose stated.
2. In combination with a revolving shaft of an engine, an eccentric formed
with a large central aperture to loosely receive the shaft, a driving disc fixed upon
the shaft and provided with a transverse groove or its equivalent across its face
extending across the axis of the shaft, corresponding feathers or projections or their
equivalent upon the eccentric to engage the groove, means for moving the eccentric
along the groove and across the axis of the shaft and there retaining it and means
for communicating the motion of the eccentric to the slide or other valve of the
engine, substantially as herein shown and described and for the purpose stated.
3. In combination with a revolving shaft of an engine, an eccentric formed with
a large central aperture to loosely receive the shaft, a driving disc fixed upon the
shaft and provided with a transverse groove or its equivalent across its face
extending across the axis of the shaft, corresponding feathers or projections or
their equivalent upon the eccentric to engage the groove, a reversing disc loosely
mounted on the shaft and provided with an eccentric groove in its face, a pin upon
the eccentric to engage the eccentric groove so that by turning the reversing disc
it will move the eccentric across the axis of the shaft, means for turning the
reversing disc at the times desired and means for communicating the motion of the
eccentric to the slide or other valve of the engine, substantially as herein shown
and described and for the purpose stated.
Dated this 19th dox of August 1895
VAUGHAN & SON,
Agents for the Applicants.