Improvements in or Applicable to Pistons, Pump Buckets, and the like.
Year: 1889

page_text: Date of Application, 19th July, 1889-Accepted, 24th Aug., 1889
Improvements in or Applicable to Pistons, Pump Buckets, and the
like.
I, WILLIAM LOCKWOOD, of Ocean Works, St. Mary's Road, Sheffield, in the County
of York, Engineer, do hereby declare the nature of my said Invention and in
what manner the same is to be performed to be particularly described and ascertained
in and by the following statement :-
This Invention relates to certain improvements in or applicable to pistons, pump-
buckets and the like.
In pistons and the like as hitherto constructed the metallic packing rings employed
have been devised and constructed to act hoth as the means of guiding the piston
relatively to and within the cylinder wall and as the means of effecting the desired
steam tight joint or closure therewith and having necessarily to be made of an area
sufficiently large to present an efficient guiding surface have presented a more than
sufficient area to effect the desired steam tight joint or closure with the cylinder wall,
all such superfluous extent for the latter purpose having been detrimental in
unnecessarily increasing the frictional surface between the piston and cylinder wall,
resulting in a corresponding waste of motive power.
It has been proposed to remedy this defect by lessoning the width of the packing
rings in a manner which in my opinion will not provide for the efficient guiding
of the piston, in consequence of which after a comparatively short wear the piston
will be of but little or no utility for its intended purpose.
The especial object of the present Invention is to render the guiding surface of
the piston distinct from the steam tight surface thereof, and to construct the former
in such a manner as that it may be from time to time set out or adjusted in
accordance with the wear of the parts and for the time being secured as thus set
out, conjointly with the reduction of the area of the steam tight frictional surface to
that which is amply sufficient for the purpose.
In carrying out the present Invention, I prefer to use as the aforesaid guiding
surface of the piston, rings of the character described in the specification of former
Letters Patent granted to me, No. 17764, dated December 24, 1887, either as con-
structed according to such Specification or as constructed according to the
description hereinafter contained for the purpose of distending the same, and
applying thereto the further improvements hereinafter described for the purpose of
effecting the desired steam tight closure. The Invention also comprises the further
application to such guiding rings in pistons of large size or where required of means
(other than those described in such Specification and herein for effecting the radial
distension thereof, and in the former for effecting the interlocking and tendency
to separation thereof where two such rings are used adjacently,) of means for
adjusting and setting the same and the piston block in concentric relation as any
variation of wear may necessitate.
On the accompanying drawings Fig. 1. represents a sectional elevation of sufficient
of a piston to illustrate an embodiment of my present improvements. Figs. 2, to, 4,
represent like views of other modifications of the Invention. Fig. 5, represents a
face view of the modifications illustrated in Fig. 4. in which but one guiding ring
s shown. Figs. 6. and, 7. respectively represent a plan view and inside elevation
of part of a guiding ring of large diameter, representing the same as adapted with
he improved means hereinafter described of distending and setting out the same.
Fig. 8, represents a partial plan view illustrating an embodiment of the means
herein before referred to for setting the guiding rings and piston block in concentric
elation, and Fig. 9. represents a perspective view broken at a part of the improved
guiding and packing rings.

page_text: 11, represents the piston block, and 12, the junk ring both of which may be
of any usual formation and may be bolted together, as at, 13, or in any other
usual or suitable manner. 14, represents the adjustable guiding rings which in
pistons of small diameter (say under 30 inches) are preferably adapted in the
manner described in the Specification of my aforesaid Patent, and shown in one
modification thereof in Fig. 9. of the drawings annexed hereto, for the purpose of
radially distending same; but in pistons over such diameter, wherein rings of very
considerable strength are required, I prefer to use the distending arrangement repre-
sented in Figs. 6, and, 7, in which, 15, represents lugs projecting inwards from the
opposite ends of the rings, 14; and, 16, represents a connecting bolt (acting also as
a stay to the joint of the ring) threaded at its ends and adapted with lock nuts, 17,
and spring-washers, 18, by means of which the rings when in position can be dis-
tended to snugly fit against the cylinder wall (the tongue piece, 19, covering the
joint of the ring ends) and when in such position the distended rings are nipped
tightly between the flanges of the piston and junk ring, and subsequently act (until
adjustment thereof is again required) as a dead ring for the purpose of guiding the
piston as aforesaid.
In order to provide for the required steam tight closure of the piston with the
cylinder wall, which the aforesaid adjustment is not intended to effect, I apply
circumferentially of such guiding rings one or more independently acting packing-
rings, 20, of relatively narrow depth to that of ordinary packing rings, making the
same of a sufficient width and thickness to serve their intended purpose, and
inserting them in circumferential grooves, 21, formed in the guiding rings. In
pistons of small diameter it is sufficient to make such packing rings, 20, of a
somewhat larger diameter than that of the cylinder in which it is to work, and to
cut a piece therefrom of such a size as that when such ring is compressed between
the guiding ring groove and the cylinder wall the ends of such spring will abut, as
in such modification the ring, 20, being made sufficiently strong its constant endeavour
to recover its normal diameter will be operative in effecting the desired steam
tight closure. In pistons of comparatively larger diameter it is of advantage to
supplement this resilient tendency of the packing ring, 20, by that of an inner flat
ribbon spring, 27, circularly curved and compressed within the said groove, 21,
behind the ring, 20, vide Fig. 2, or by that of a similarly arranged spring, 27, made
of a curvilinear formation, vide Figs. 4, and, 8, the latter form of spring being very
effective, its action being augmented by its confinement between the packing ring
and the unyielding guiding ring.
One or more of such guiding rings may be used in the construction of a piston
or the like, and each such ring may be fitted with one or more of such packing
rings. Figs. 1. and, 2. illustrate modifications in which two guiding rings are used,
each being adapted with a packing ring arranged about centrally of its width. Fig. 3.
illustrates an arrangement in which the guiding rings are fitted with adjacent
packing rings, 20. When the packing rings are thus juxtaposed it is of advantage
to annularly recess their opposite faces and to fit between such opposite recesses a
coiled spring, 22, of a circular form in plan view of a somewhat larger diameter
than that of the annular recess from side to side of the piston, and of an undulating
or curvilinear forun in side elevation, as when compressed into and between the
grooved faces of the packing rings such spring will have a constant tendency to
separate the rings, 20, and also to distend them against the cylinder walls.
The guiding rings may be made in segments, in which event the means of dis-
tending them would require to be correspondingly duplicated; the said packing
rings may also be made in disconnected segments in which event the adjacent ends
thereof may be recessed as at, 23, and fitted with coiled springs, 24, vide Fig. 5, the
joints being closed from the inside of the rings by filling up pieces, 25.
I also in accordance with the present improvements apply to such aforesaid adjust-
able guiding rings, inner projecting parts, 28, and ineans of adjusting the same
relatively to the piston block, 11, so that the guiding and packing rings and piston-
block shall be arranged in concentric relation, these means preferably consist of

page_text: adjustable screws, 26, the adjustment being effected by screwing the same against the
piston block as may be required, vide Fig. 8.
Thus, when, in pistons constructed according to the present improvements, there is
any appreciable wear of the guiding rings or of the parts against which they work,
such rings may be readjusted by loosening the junk ring, in the modification
represented in Fig. 9. or by removing the junk ring and adjusting the nuts, 17, in the
modification illustrated in Figs. 6, and, 7, and secured in the re-adjusted position by
screwing up the junk ring.
Having now particularly described and ascertained the nature of my said Inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is.
1. The herein before described improvements in or applicable to pistons pump
buckets and the like.
2. Constructing the guiding surface of pistons and the like distinct from the steam
tight surface thereof and in such a manner as that it may be from time to time set out
or adjusted in accordance with the wear of the parts and for the time being secured
as thus set out substantially as hereinbefore described.
3. Constructing pistons and the like with a guiding surface distinct from the steam
tight surface thereof and in such a manner as that it may be from time to time set
out or adjusted in accordance with the wear of the parts and for the time being
secured as thus set out in combination with packing rings of relatively narrow
formation and circumferentially applied thereto substantially in the manner herein-
before described.
4. The use in combination with the subject matter of the preceding claim of flat or
curvilinear springs for aiding in distending the packing rings, substantially as
herein before described.
5. The use in combination with the subject matter of claim, 3, and with the subject
matter of claim, 4, of means for adjusting and setting the guiding rings, the
packing rings and the piston block in concentric relation as any variation in wear
may necessitate, substantially as hereinbefore described.
Dated this 15th day of July 1889.
DAY, DAVIES & HUNT,
321, High Holborn, London, W.C., Agents for the Applicant.