Improvements in Pistons.
Year: 1898

page_text: Improvements in Pistons.
I, JOHN GEORGE AULSEBROOK KITCHEN, of 44, Albert Road, Alexandra Park,
Manchester, in the County of Lancaster, Mechanician, do hereby declare the
nature of this invention to be as follows:-
-
This invention relates to improvements in pistons and has for its object the
more perfect fitting in and adjustment of the piston in the cylinder.
The improvements are embodied in the construction hereinafter set forth. A
disc or block made to fit the cylinder and slide therein is formed with a central
boss of suitable length and diameter. Upon this boss are placed close together
a number of dished plates of suitable thin metal nested into one another with
the concave faces to the disc or block aforesaid. The plates have a number of
radial slits therein extending to some short distance from their central holes, and
the slits are so arranged that those in one plate do not come opposite those in the
next. The plates are prevented from turning round on the boss by a feather
or key or by other suitable means. Upon the end of the boss is fixed a rigid
cap having a concave face towards the plates aforesaid, and having its edge in
contact with the end plate. The peripherial surface of the plates is turned to
fit the cylinder and as the surface wears the central part of the flexible dished
plates is pressed towards the rigid disc aforesaid by suitable means, tending to
The expan
Hatten the plates which being radially slit expand in circumference.
For instance three or
sion of the plates may be effected by any suitable means.
more set screws bearing against a flat disc next to the end plate, screwed into the
cap at a suitable distance from the centre thereof may be used for this purpose,
or a nut screwed upon the boss and bearing against the end flexible plate may be
screwed against the plates by turning the cap aforesaid.
The disc or block aforesaid is suitably formed to receive the piston rod or con-
necting rod.

page_text: 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:-
The invention relates to improvements in pistons and has for its object the
more perfect fitting and adjustment of the piston in the cylinder.
In order that my invention may be more readily understood, I have attached
hereunto a sheet of drawings to which I will now refer. In the said drawings
Fig. 1 represents a part sectional elevation and Figure 2 an end elevation of a
piston suitable for a single action cylinder lying in a horizontal position with
respect to its axis, constructed in accordance with my invention. Figures 3
and 4 are similar views of a modified arrangement of the parts of the piston.
Figure 5 illustrates also similar sectional views of my improved piston adapted
for a double action cylinder. Figures 6 and 7 represent two views of one of the
plates of which my improved piston is chiefly built up.
In carrying out my invention I form a disc or block a to fit the cylinder so as
to slide therein, and, of sufficient length to provide an effective wearing surface.
In the case of a piston as illustrated in Figures 1,to 4 which is applicable for
single action cylinders, a comparatively long boss a¹ is provided preferably
having a screwed part a² and a reduced screwed end a³. Upon this boss is mounted
a series of dished plates 6 lying close together, the edge of the first one resting
against the disc or block a. Figures 6 and 7 illustrate one of the dished plates 7.
Each plate has a central hole of similar diameter to that of the boss a¹, and is
provided with a number of radial or approximately radial slits 62 extending from
the periphery to some little distance from the central hole 61. These plates are
sufficiently dished to enable their periphery to expand in circumference under
pressure about their centre, so as to provide for a limited amount of circum-
ferential wear. The plates are so disposed upon the boss a¹ that the slits. in one
plate do not come opposite those in the plate next to it. In order to ensure this,
a feather 63 is fixed upon the boss and a slot 64 is formed in each plate to engage
with the feather, the positions of the slots with respect to the slits being varied
in some or all of the plates. In order to enable the plates b to be pressed up
against the disc a a nut c is fitted upon the screwed part a² which by being screwed
towards the disc tends to flatten the plates 6 and increase their circumferential
measurement. A shield or cap d having a concave faced the edges of which
press against the end plate of the series b, and a central hole formed to fit the
reduced end a³ of the boss a¹ is freely mounted upon the boss and is secured
thereon by a nut a In order to enable the nut c to be turned round without
first removing the cap d, the cap is formed with a box to loosely fit the nut, or
an equivalent device, so that by turning the cap round upon the end a³ the nut c
will be also turned round while being free to move axially independently of the
cap.
In the modification illustrated in Figures 3 and 4, the position of the concave
faces of the plates b with respect to the disc a is reversed. The said disc is
formed with a concave face a³ the edge of which bears against the series of
plates b. The boss a¹ is also furnished with a cap d which is secured at the end
of the boss by the nut a'. In order to expand the plates, preferably, in the case
of trunk pistons I mount a collar c¹ upon the boss a¹ between the disc a and the
series of plates 6, and I arrange three or more set screws in the disc to bear
against the collar c and press it towards the plates b. In other cases the collar d
forms a nut which is screwed upon the boss and which can be adjusted to the
degree required by first removing the cap d and plates b. Or I may use any
other suitable known device for expanding the circumferential surface of the
plates by reducing the convexity thereof.
Referring now to Figures 5 and 6 which illustrate the application of my
improvements in the case of a piston for a double action cylinder, one example
only corresponding with that illustrated by Figures 1 and 2 is shewn, but the
arrangement of plates, illustrated in Figures 3 and 4 is equally applicable. In
this case the disc or block a is centrally disposed; the piston rod p passes through

page_text: the disc and has the plates b mounted thereon with their concave side to the disc.
The adjustment of the plates b upon each side of the disc a is effected by the
nuts c in a similar manner to that illustrated in Figures 1 and 2.
Figures 6 and 7 illustrate in two views the plates b. These are preferably
stamped from sheet steel, but any other metal of good wearing quality and having
some elasticity is suitable. The plates after being assembled are turned upon a
mandrel, or when attached to the disc, to fit the cylinder.
In the several views the plates bare shewn of conical form, but they may
equally well be made with a spherical or other suitably curved surface. The
thickness of the plates 6 will vary with their diameter, and in the larger sizes
more slits than are shewn may be made in each plate. The flexibility of the
plates may also be increased by piercing them with holes in the path of the slits
or between the slits.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:-
First: The improved construction of pistons which consists in arranging a
suitable number of dished plates each having a central hole and radial or approxi-
mately radial slits extending from the edge to some distance from the central
hole, upon a boss or shaft carried by a disc or block forming the body or trunk of
the piston, a terminal plate or terminal plates for securing the dished plates
against the disc and a screw adjustment for pressing upon the convex side of the
plates in order to increase their circumferential measurement substantially as
and for the purpose herein before described and illustrated in the several figures
of the drawings.
Second: The improvements in pistons substantially as herein before described
and illustrated with reference to Figures 1, 2, 6 and 7 of the drawings.
Third: The improvements in pistons substantially as herein before described
and illustrated with reference to Figures 3, 4, 6 and 7 of the drawings.
Fourth: The improvements in pistons substantially as hereinbefore described
and illustrated with reference to Figures 5, 6 and 7 of the drawings.
Dated this 22nd day of November 1898
R. J. URQUHART,
57, Barton Arcade, Manchester,
Harrington Chambers, 24, North John Street, Liverpool,
Consulting Engineer and Patent Agent.