A. NEW MECHANISM OF: DISTRIBUTION WITH MOTION FROM THE ROD APPLICABLE TO ANY KIND OF STEAM ENGINES
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Theophile Desgrandschamps at the
Office of the Commissioners of Patents, with his Petition, on the 24th
June 1862.
I, THEOPHILE DESGRANDSCHAMPS, of No. 75, Rue de Charenton, in the
City of Paris, in the Empire of France, Mechanician, do hereby, declare the
nature of the said Invention for "A. NEW MECHANISM OF: DISTRIBUTION WITH
MOTION FROM THE ROD APPLICABLE TO ANY KIND OF STEAM ENGINES," to be as
follows:-
My improvements are applicable to all steam engines, and offer the following
advantages.
each end of the length of the
hole or steam port is nearly
Firstly, the slide valve opens very rapidly at
stroke of the piston, the opening of the inlet
complete about the twentieth of the stroke, which on the one: hand permits the
steam to arrive as it were simultaneously behind the piston at the beginning.
of its stroke; and, to .act immediately with all its. expansive force, and on the
other hand permits the same steam when it has pushed the piston to the end
of its stroke, and thus completed its work, to: escape freely, without producing !
the back pressure, which is the fault of existing, distributors..
- Secondly, this distribution. permits the steam. to act by expansion at all
points of: the stroke of the piston at the will.of the.engineer,. starting from the:.
fourth of the stroke..

page_text: Thirdly, certain pullies, collars, eccentric rods, and other pieces are replaced
by a more simple apparatus, which may be kept in working order at less cost.
The movement which works my distributing apparatus is taken from the
connecting rod.
This means is not new in itself, but in its application, which consists in
transmitting the motion of the connecting rod to a slide, which forms the
principal part of my Invention, and which by its particular arrangement and
combination with the other parts of the mechanism constituting the dis-
tributing apparatus forms a whole, by which novel results are obtained, no
distributor yet constructed permitting the advance of the slide valve to be varied
at will, and this is the principal property of the slide above-mentioned.
This slide receives its motion from the connecting rod by means of a pin
or crank pin fixed on a piece attached to the bolt of the cross bar or
butt of the piston, and which by means of two cranked arms embraces the
connecting rod, forming as it were one piece with it. The pin or crank
pin fixed in the middle of the cranked arms carries a side block in
contact with the interior of the slide, to which it transmits the move-
ment which it has received from the connecting. rod by means of the piece
above-mentioned.
This movement in a revolution of the driving wheel
has followed the contour of a very elongated ellipsis, of which the different
points of the slide must simultaneously follow the contour. The slide
valve will receive a motion governed by the forms of this curve, that is
to say, very rapid at each end of its course, and which will be transmitted to
it as follows:-The slide is united at its upper part by a hinged piece
to another piece T-shaped, which oscillates on a pin which it carries in
the middle of its arms; at each end of these arms is bolted the sector
or slide known as "Stephenson's"; the sector has therefore the same oscil-
lating movement as the two arms of the piece to which it is attached,
and like it oscillates on its centre. It is this sector which transmits the
come-and-go motion to the slide valve by "means of a connecting rod;
this movement of the slide, valve has the more amplitude accordingly as the
extremity of this rod, (which carries a slide block sliding in the sector,)
increases its distance from the centre of rotation, whether in forward or
backward course. The slide carries an extension or projection, which is
attached to a system of levers, with moveable hinge and point of rotation
so that it may také different positions on the quadrant; it will be under-
stood that the slide must also assume different positions, and slide from
bottom to top and top to bottom, in the piece which serves it for guide.

page_text: The slide will turn around the pin, which will serve as point of rotation.
These different positions, more or less inclined, will correspond with the
different movements which it is desired to obtain from the slide valve. In
every position the slide will transmit to the slide valve the movement which it
will have received from the connecting rod by means of the pin or crank
pin.