Year: 1888

page_text: Date of Application, 5th Jan., 1888
Complete Specification Left, 19th Sept., 1888
Complete Specification Accepted, 19th Oct., 1888
I FRANÇOIS FERNAND BOURDIL, of 24 Rue de Téhéran, Paris, France Engineer,
do hereby declare the nature of this invention to be as follows:-
My invention relates to an improved self-regulating piston and it consists essentially
in the employment of one or more springs for automatically regulating the pressure
of the packing against the sides of the cylinder or pump barrel, whereby the objections
consequent upon the excessive tightness or looseness of the packing are entirely
avoided, at the same time that a perfectly steam or water tight fit is obtained with
but little friction, this being absolutely dependent upon the force of the springs
employed.
It has been before attempted to apply springs to piston packings by placing them
between the packing and the piston rod, but in this arrangement the spring directly
presses the packing radially against the cylinder which presents certain objections and
necessitates the construction of the packing in segments of which the joints although
not opposite each other are a cause of loss of pressure.
The distinctive feature of my invention consists in disposing the packing between
a pair of discs forming the piston heads which are constantly pressed towards each
other in a longitudinal direction by the action of springs, so as to force the packing
against the sides of the cylinder. In this manner the springs act upon the movable
discs and not directly upon the packing which may be of any desired length.
Reference is to be bad to the accompanying drawings which illustrate my invention
as applied to two different kinds of pistons. Figure 1 shows an ordinary solid piston
provided with my improved packing and figure 2, a piston similarly provided having
a hollow rod for the passage of the liquid through the piston.
a figure 1 is the piston rod upon which slide freely the discs 6 having the packing c
placed between them. The discs b b are pressed towards each other by springs d
(which may be of flat, spiral, or other kind) held against the discs by nuts e, or
shoulders, pins, or other fixed points on rod a.

page_text: In figure 2, spiral springs d are employed surrounding the piston rod a which is
hollow and terminates in a cage containing a ball valve the springs being confined
between shoulders c on the piston rod and the heads of the piston.
It will be seen that in both cases, it is the thrust of the springs which regulates the
pressure of the packing upon the sides of the cylinder or pump barrel, the distance
between the discs depending upon the volume of the packing, and the elasticity of
the springs compensating for wear of said packing and ensuring constant uniformity
in the working of the piston.
The form, dimensions, and arrangement of the several parts of this improved
packing may be varied without departing from the invention. For example, instead
of making both discs b movable and compressible by springs one only of said discs
may be movable and the other be fixed. The packing etc., may be made of any
suitable material, and the improvements are applicable to all kinds of pistons.
Dated this 5th day of January 1888.

page_text: COMPLETE SPECIFICATION.
Improvements in Pistons.
I, FRANÇOIS FERNAND BOURDIL, of 24, Rue de Téhéran, Paris, France, 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:-
My Invention relates to an improved self-regulating piston; and it consists
essentially in the employment of one or more springs for automatically regulating
the pressure of the packing against the sides of the cylinder or pump barrel, whereby
the objections consequent upon the excessive tightness or looseness of the packing
are entirely avoided at the same time that a perfectly steam, or water tight fit is
obtained with but little friction, this being absolutely dependent upon the force of
the springs employed. It has been before attempted to apply springs to piston
packings by placing them between the packing and the piston rod, but in this arrange-
ment the spring directly presses the packing radially against the cylinder which
presents certain objections and necessitates the construction of the packing in
seginents of which the joints, although not opposite each other, are a cause of loss of
pressure.
The distinctive feature of my invention consists in disposing the packing between
a pair of discs forming the piston heads which are constantly pressed towards each
other in a longitudinal direction by the action of springs, so as to force the packing
against the sides of the cylinder. In this manner, the springs act upon the inovable
discs and not directly upon the packing, which may be of any desired length.
Reference is to be had to the drawings left with my Provisional Specification,
which illustrate my invention as applied to two different kinds of pistons. Figure 1
shews an ordinary solid piston provided with my improved packing, and figure 2 a
piston similarly provided having a hollow rod for the passage of the liquid through
the piston.
a, figure 1, is the piston rod and the piston heads or discs sliding freely thereon
and having the packing c placed between them. The discs bbare pressed towards
each other by springs d (which may be of flat, spiral, or other kind) held against the
discs by nuts e, or shoulders, pins, or other fixed points, on rod a. In figure 2, spiral
springs d are employed surrounding the piston rod a which is hollow and terminates
in a cage containing a ball valve f, the springs being confined between shoulders e on
the piston rod and the heads 6 of the piston having the packing c between them.
It will be seen that in both cases, it is the thrust of the springs which regulates the
pressure of the packing upon the sides of the cylinder or pump barrel, the distance
between the discs depending upon the volume of the packing and the elasticity of the
springs compensating for wear of said packing and ensuring constant uniformity in
the working of the piston.
The form, dimensions, and arrangement of the several parts of this improved
packing may be varied without departing from the invention. For example, instead

page_text: of making both discs 6 movable and compressible by springs one only of said discs
may be movable and the other be fixed.
The packing, etc., may be made of any suitable material, and the improvements are
applicable to all kinds of pistons.
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 :-
The herein described construction of self-regulating piston which consists essentially
of a pair of discs with a packing between them, one or both discs being movable on
the piston rod and being pressed together by one or more springs, as and for the
purpose specified.