Year: 1886

page_text: Date of Application, 19th Nov., 1886.
Complete Left, 8th Jan., 1887.
Complete Accepted, 8th Feb., 1887.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of the said Invention to be as follows:-
The object of this invention is to provide for steam engines, a device in which
the reversing of the valve motion is effected by shifting the eccentric transverely on
a shaft.
To the engine shaft is secured a hub having collars, between which is placed the
eccentric which is preferably formed of two parts secured together by bolts.
The eccentric has a central aperture with parallel sides, and slides on guides formed
on the parallel edges of the collars and the adjustment of the eccentric relative to the
crank of the engine is effected by turning the hub upon the shaft.
Oppositely directed wedges are fitted to mortises formed in diametrically opposite
sides of the hub and flanges attached thereto, and are provided with stems which are
connected with a circumferentially grooved sliding collar placed loosely on the shaft.
The inclined surfaces of the wedges engage the inner surface of the eccentric in the
ends of the slot formed in the eccentric, so that by moving the sliding collar length-
wise upon the shaft, one of the wedges will be drawn into the eccentric, and the other
will be removed therefrom, so that the eccentric will be moved transversely with
reference to the shaft. The proportion of the wedges is such as to admit of moving
the eccentric in the manner already described, sufficiently to reverse the engine, and
to give its valve as much stroke as may be required.

page_text: When the eccentric is in a central position, its periphery will be concentric with the
shaft, and the eccentric strap and rod connected therewith, will not be moved.
By moving the sliding collar in one direction or the other, any desired amount of
throw may be given to the eccentric rod.
For convenience in moving the sliding collar I provide a forked arm of the usual
description, and arrange in connection therewith, any of the well known devices for
retaining the arm in the position in which it may be placed.
The advantage obtained by this improvement is, that the joints and rods required
where links are used are entirely avoided, and a correct movement of the valve is
always ensured,
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.

page_text: COMPLETE SPECIFICATION.
Improved Reversing Mechanism for Steam-engines.
I, ALEXANDER MELVILLE CLARK, of the firm of A. M. and Wm. Clark, of
53, Chancery Lane, in the County of Middlesex, Fellow of the Institute of Patent
Agents, do hereby declare the nature of this Invention (a communication to me from
abroad by William Elwood Tally of Shipman in the County of Macoupin and State of
Illinois United States of America Farmer) and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement:
The object of this Invention is to provide for steam engines a device in which
the reversing of the valve motion is effected by shifting the eccentric transversely
on a shaft.
The Invention consists in the construction and arrangement of parts, as will be
hereinafter fully described and claimed.
Reference is to be had to the annexed drawing forming part of this specification in
which figure
is a side elevation; figures 2 and 3 are sectional views shewing the
working parts of the reversing mechanism; and figure 4 is an end view of the hub
which carries the eccentric. Similar letters of reference indicate corresponding parts
in the different figures.
To the shaft. A of the engine is secured a hub B having collars EE between which
is placed the eccentric F which is preferably formed of two parts a a¹ secured together
by bolts. The eccentric has a central aperture with parallel sides, and slides on
guides formed on the parallel edges of the collars E E, and the adjustment of the
eccentric relative to the crank of the engine is effected by turning the hub B upon
the shaft A. Oppositely directed wedges G G are fitted to mortises formed in
diametrically opposite sides of the hub Band flanges attached thereto and are pro-
vided with steinse which are connected with a circumferentially grooved sliding
collar H placed loosely on the shaft. The inclined surfaces of the wedges G G
engage the inner surface of the eccentric F in the ends of the slot formed in the
eccentric, so that by moving the sliding collar H. lengthwise upon the shaft A one of
the wedges will be drawn into the eccentric and the other will be removed therefrom
so that the eccentric will be moved transversely with reference to the shaft A. The
proportion of the wedges is such as to admit of moving the eccentric, in the manner
already described, sufficiently to reverse the engine and to give its valve as much
stroke as may be required.
When the eccentric F is in a central position, its periphery will be concentric with
the shaft, and the eccentric strap and rod connected therewith will not be moved.
By moving the sliding collar H in one direction or the other, any desired amount of
throw may be given to the eccentric rod. For convenience in moving the sliding
collar H, I provide a forked arm of the usual description, and arrange in connection
therewith any of the well-known devices for retaining the arm in the position in which
it may be placed.

page_text: The advantage obtained by this improvement is, that the joints and rods required
where links are used are entirely avoided, and a correct movement of the valve is
always ensured.
Having now particularly described and ascertained the nature of the said Invention,
and in what manner the same is to be performed, I declare that what I claim is ;-
1. The tubular lub B, having diametrically opposite slots parallel with its axis and
collars E E provided with parallel guiding edges, in combination with the eccentric F
between the collars and guided by the said edges, the wedges G.G¹ oppositely
arranged with respect to each other and working in the slots in the hub against the
inner edges of the eccentric, and the sliding collar H to which the wedges are joined,
substantially as set forth.
2. The combination with the shaft A and the tubular hub B secured thereon so as
to revolve therewith and having the diametrically opposite slots parallel with the axis,
and the collars E E' having parallel guiding edges 6, of the eccentric F formed in two
parts a a secured together between the collars E E¹ and with an opening having
parallel sides sliding on the guides bb, the oppositely arranged wedges G G₁ working
in the slots in the hub against the inner edges of the eccentric opposite those
engaging the edges b and having stems c c and a collar H, substantially as set forth.
A. MELVILLE CLARK.
By A. M. & Wm. Clark,
53, Chancery Lane, London,
Patent Agents.