A NEW MECHANISM TO REVERSE THE MOTION OF STEAM ENGINES, FARTICULARLY OF LOCOMOTIVES
Year: 1852

page_text: PROVISIONAL SPECIFICATION left by Auguste Edouard Loradoux
Bellford at the Office of the Commissioners of Patents, with his
Petition, on the 20th October 1852.-A communication.
(Void by reason of notice to proceed not having been given within the
time prescribed by the. Act.)
I, AUGUSTE EDOUARD LORADOUX BELLFORD, of 16, Castle St., IIol-
born, in the City of London, (Patent Agent,) do hereby declare the
nature of the said Invention for "A NEW MECHANISM TO REVERSE THE
MOTION OF STEAM ENGINES, FARTICULARLY OF LOCOMOTIVES," to be as
follows:-
The ordinary process employed to reverse the motion of a locomotive
(that is to say, to obtain the backward motion when the machine is
moving forward, or the forward motion when the machine is moving
backwards, consists in moving, by the aid of levers, the slides of the
machine, & to put them in communication with the eccentrics of the
backward motion, or with the eccentrics of the forward motion, accord-
ing as is required the forward or the backward motion. This new
process to reverse the motion of locomotives consists in transforming
at will, & simultaneously, the portion of steam pipe near the slides
into a blast pipe, and the lower portion of the blast pipe into a steam

page_text: pipe, without touching the slides, which remain in communication with
the same eccentrics. Steam is thus introduced into the cylinders by
the slides by passing externally or internally, according as the machine
is going backward or forward. At the moment of transformation of
the blast pipe and steam pipe the steam, which begins to escape from
one side of the piston, suddenly returns and repulses the piston, and
imparts the retrograde movement to the driving wheels of the machine
precisely as in ordinary machines when the motion of tlic slide is re-
versed. Only in this new system a special arrangement prevents the
rising of the slides when the steam at the moment of reversing the
motion is introduced to the interior of the slides. The transformation
of the extreme portion of the steam pipe into a blast pipe, and, simul-
taneously, of the lower portion of the blast pipe into the steam pipe, is
obtained either by the aid of a two way cock, or by the aid of a straight
action slide, or by the aid of a circular action slide, or by the assistance
of any other mechanisin to take the place of a two way cock.
First, the circular slide:-Fig. 1, is a side view of this contrivance;
Figures 2, & 3, are front views of the same; & Fig. 4, is a plan of the
slide. The pipe G, Fig. 1, is not shown in Figures 2, & 3, in order to
make the description clearer. A, is the steam pipe; it communicates
at its upper end with the boiler of the machine. D, is a circular motion
slide, placed on a metallic table, into which are soldered below the
pipes B, and C; it turns round the lower extremity of the pipe A, and
also round a spindle X, fixed in the table; its course is limited to
about a sixth of circumference, and it receives its movement by the aid
of a handle K, Figure 4, placed within reach of the engine driver. This
slide presents internally an opening h, which communicates above
permanently with the pipe A, & which below is put at will in com-
munication with one or other of the pipes B, & C. This slide
presents besides two openings e, & f, which permit to be put in com-
munication with the escape pipe G, either of the pipes B, & C. These
two openings, & f, discharge into the escape pipe G, serving to
carry into the chimney to accelerate the draught, the steam going out
by the pipes B, & C. The escape pipe G, is enlarged at the base, so
as to enclose at once the openings e, & h, Fig. 4; its base scarcely

page_text: touches the circular motion slide D. The pipe B, communicates by
its lower extremity with the exterior of the slides of the locomotive,
and the lower part of the pipe C, communicates with the interior of
these same slide. Figs. 2, & 3, show the two positions which the
slide D, occupies according as the machine goes backwards or for-
wards. In Figure 2, the pipe C, is in communication with the pipe A,
and it serves as a passage for the steam; at the samne moment the
pipe B, communicates with the opening e, and serves as an escape-
of steam
ment coming from the cylinders of the machine. In Figure 3, on the
contrary, the pipe C, serves as an escapement for the steam coming
whilst
from the cylinders as soon as the pipe B, is in communication with
the pipe A, & serves as a passage for the steam. Thus, when the
engine driver wishes to move the machine forward he has only to
bring the opening, above the pipe B, and when he wishes to produce
a backward motion he must bring the opening h, above the pipe C.
The mechanism which has just been described is much less complicated
than that usually adopted in locomotives. There needs only one
eccentric for each slide in place of two, & it allows to apply in a
simple manner, as will be shown. the variable expansion of the steam,
and this expansion may be measured with precision. Stephenson's
slide produces variable expansion, because it allows the diminution, at
will, the length of the run of the slidles of the machine. In this system
the expansion of the steam is so much the more prolonged as the
length of the run of the slides is diminished. Thus, any apparatus
which will allow to diminish at will the length of tho run of the slides
to be diminished at will, will produce expansion of the steam as effected
by Stephenson's slide. The expansion apparatus applicable to the
changing of the motion is described and represented in Fig. 5. A, is
one of the slides of the machine; it is set in motion by the eccentric
B, by means of the rod C, D; the run of the slide, when there is no
expansion, is equal to the distance C, E. The rod C, D, is furnished at
its extremity C, with a button placed in the interior of the suspending
groove C, F, and in which it can slide with a gentle friction from C, to
F; to this button is attached a chain C, F, G, H, passing over two

page_text: pulleys placed at the points F, and G, and hooking on the point H,
situated within reach of the engine driver. When the engine driver
wishes to produce expansion he moves the disk H', by drawing the
handle H, L, towards him, up to the point K, for instance. The chain
then rolls itself up upon the disk up to the point H, and raises the
extremity C, of the rod C, D. The rod C, D, then takes the position
C', D', and the run of the slide, which was equal to C, E, is reduced to
C, E. The disk is furnished with a catch or pressing screw, which
serves to maintain it in the position from which it was brought. One
of the end side edges of the handle H, L, marks on a dial m, n, o,
with triple graduation the length of the run of the slide, the length
of the expansion and of the compression. These indications can be
given with great exactitude, as the run of the slide is small, com-
paratively to the developement of the dial m, n, o. Each of the two
slides of the machine must be furnished with an apparatus for expan-
sion similar to the one just described.