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Патент USA US2059728

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Nov; -3, 1936'. ' A
lÉ». mick¢
PACKING CUP
_ _2,059,728` ’ y
_
FiledI 'May 29. 193s
` Fig@ 79
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Inventor".
¿BURNS DICK;
‘
- 2,059,128
`.Patented Nov. _3, l1936
UNITED STATES PATENT Aori-*ice
rs(,:Zrißlrîï‘:azur'A
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I
Burns Dick, Ferguson, Mo., assigner to Wagner
Electric Corporation, St. Louis, Mo., a corpo
ration of Delaware
Application May 29, 1933, Serial No. 573,367 `
10 Claims. (Cl. 309-34)
My invention relates to packing cups for pis
the compressor piston packing cup being shown
in Figure 4 of Loughead Patent No. 1,847,402 is
tons and more particularly to improvements in sued March 1,1932, and an exampleof the motor
packing cups used in fluid pressure producing s piston packing cup be ing shown in Figure 1 of
systems, as for example, hydraulic braking sys
pliver Patent No. 1,711,206 issued April 30, 1929. 5
tems,
for
preventing
the
escape
of
fluid
under
These rubber cups rely on the resiliency of the
5
'pressure past the piston.
l
rubber to retain the seal between the lip of the
One of the objects of my invention is to pro
cup and the cylinder wall. This resiliency, how
duce a packing cup of iiexible material, the-lip ever, is. destroyed ' if overheatingA occurs, or if
or edge of which will engage the wall of the cyl- _. the rubber is depreciated by the use of a poor 10
throughout its cir liquid, thereby resulting in an ineiiicient seal, »
10 inder with a uniform pressure
cumference.
-
Another object of my invention is to so con- -
struct a flexible packing cup that the radial pres
sure between the lip and the cylinder will be
15 produced by an expansible means carried by the
cup and acting at substantially right angles to the
' especially when the cups areëixli a non-operative
position.
The compressor cups -are also generally held
'against the head of the piston 3 by a retracting
spring I4 bearing on its iiat central portion which
also tends to draw the lip of the cup inwardly
wall of the cup.`
‘
and thus reduce its pressure on the cylinder wall.
Other objects of my invention are to produce
Attempts have been made in the past' to use
a packing cup of flexible material, as for exam
springs to expand the lip of the cup and create
ple, rubber, moulded cellulose compound, or light , -a uniform pressure between the lip of the cup
metal, that will be simple in construction, eco
and the cylinder wall, but these constructions
impracticable because the
nomical to manufacture, and _which will oper
have been found to bedirect
ate eiliciently for a long period of time.>
outwardly radial di
spring operates in a
Still other objects will become apparent from ' rection and a very small increase or decrease> of 25
the following description of three embodiments the diameter in which they act, causes a, very
of my invention takenin connection with the large increase or decrease in the radial pressure
accompanying kdrawing in which Figure l is a of the'spring, thus producing unsatisfactory seal
view, partly in cross section, of" the fluid parts of ing results under diffe rent operating conditions.
a braking system equipped with two forms of
In accordance with one embodiment of my in 30
30
cups embodying my invention; 'Figure 2 is a cross
sectional view of the packing cup in the fluid
compressor; Figure. 3 is a cross sectional view of
` one of the packing cups in the brake actuating
motor; Figure 4 is «a cross sectional view of a
metal packing cup embodying my invention; and
Figure 5 is an enlarged view of a portion of the
cup in Figure 4 showing .its relation to the cylin
der wall.
'
.
vention, the rubber packing cup I2 for the com
pressor is provided at its forward end withv an
integral inwardly extending circumferential
iiange I5 which forms, with the inner wall ofthe
recess or groove I6. An
cup, a circumferential I1 is interposed between
expansible coil spring
.the base of the cup and the groove IB and acts on
the'flange I5 in a direction substantially parallel
to the axis of the cup and at a distance from the
peripheral wall of thel cup. The spring I‘I is of 40
vReferring to the drawing in detail, the nu
meral I indicates the well known compressor of 'such resiliency and dimensions that it has a a hydraulic brake system which is provided with considerable working range, thus producing a
a cylinder 2, a piston 3, and a reservoir t com
substantially uniform axial force over a. con
municating with -the cylinder ahead and at the ' siderable distance in its path of expansion. The
rear of the piston in its retracted position by force produced by the spring upon the ilange I5 45
45 the passages 5 and 6. The cylinder of thecom
the cup to be stretched and the lip thereof
pressor is connected to the brake shoe actuating causes
to be expanded outwardly, as shown by the dotted
‘ motors 1 by- a conduit 8 (one motor only being line of Figure 2. This radial expansion is a re
shown). The motor comprises a cylinder 9 and suit- of the reaction caused by the spring I‘I`
a pair of pistons I0 adapted to actuate the ends acting on the flange at a point spaced fromthe 50
the brake shoes II. Since the braking system line of support of the forward edge of the lip of
'50 of
must be as fluid-tight vas possiblathe pistons 3 the cup. The inner wall of the cup is tapered to
andl >I0 are provided with packing cups .I2 and
cause the 'extreme forward edge ofthe cup to
I3 respectively.
.
,
l'
Y
have the greatest radial expansion. As the ends
In the brake systemsV now in use, the packing of the coiled spring are in contact with the iiange
65 cups are constructed of rubber, an example of
2
9,059,728
IB at all points, the outward expansion of the lip
of the cup will be uniform, thus producing a uni
form pressure between the cup and the cylinder
wall. 'I'he large working range of the spring I1
also insures that pressure between the walls of
the cup and cylinder will be maintained through
out the wearing life of the cup. i
coiled spring expanding in the axial direction of
thecup and producing a force acting on the in
wardly extending part of the cup 'and in a direc
tion substantially parallel to tlîe cup axis.v
3. A packing cup having a flexible cylindrical
wall carrying an inwardly extending part at its
forward end, and a-n axially expansible coiled
The inner surface of the base of the cup I2 is
made convex and has mounted thereon a convex
_spring acting in a direction substantially parallel
10 retainer I8 against which the end of the spring
ing said inwardly extending part at a distance
from the wall of the cup.
Il abuts. The purpose of this construction is
to prevent the rubber in the base of the cup
from floating radially outwardly by the action
of the spring Il and also to prevent any tension
15 in the inner peripheral wall of the cup which
causes the inward4 deflection of the lip of the cup
previously referred to.
Referring to Figure 3, I have disclosed my in
vention applied to a packing cup made from
20 semi-flexible moulded material, as forexample,
-a cellulose compound. The cup I3 is shown as
screwed to the head of the piston I Il and the lip
portion provided with an inwardly extending `cir
cumferential flange I 9. The intermediate wall
25 of the cup is of less thickness than the base por
tion` to provide flexibility whereby the lip portion
may be expanded outwardly. 'I'he flange I9
is also radially corrugated, as shown, to permit
of this expansion. 'I'heexpansible spring 20 is
30 interposed between _the head of the piston and
the flange I9 as shown.
,\
'
In assembling the structure, the lip of the
cup is normally formed to snugly fit the cylinder
and then the spring released after the cup -is
35 placed in the cylinder. The „radial expansion
caused by the spring, and shown in dotted lines,
need not be great under these circumstances in
order to create sufficient sealing pressure be
tween the lip and the cylinder wall.
40
'
In Figures 4 and 5, I have shown my inven
tion' applied to a cup made from thin, flexible metal, as for example, brass. In this construc- `
to the axis of the cup and having one end engag
4. A packing cup having a flexible cylindrical
wall provided with an inwardly extending cir
cumferential flange at its forward edge, and
means forcing the external forward edge of said 15
wall outwardly, said means comprising an ex
pansible coiled spring engaging the base of the
and the iiange, the force exerted by said
s'pring being in a -direction substantially parallel
to the axis of the cup and acting on the flange at 20
a distance from the wall of the cup.
'
5. A yieldable packing cup having a base por
tion and a yieldable cylindrical wall, the forward
end of said wall being provided with an integral
inwardly extending flange forming a l circum
25
ferential groove, and an axially expansible coiled
spring having one end engaging the base of the
cup and the other end engaging the flange at
said groove.
'
6.
packing member having a flexible' wall
an
inwardly extending circumferential flange
at ts orward end, said flange being so formed
that its' internal diameter may be slightly in
creased to thereby permit slight circumferential
expansion of the forward end of the packing 35
member, anda coiled expansible spring axially
positioned within said cylindrical wall and exert
ing a force upon the flange in a direction sub
stantially parallel to the axis of the cup whereby
the forward edge of the wall will be forced radial 40
ly outwardly.
7. A packing member having a flexible wall
and an inwardly extending circumferential flange
nular flange ring 23 is soldered or otherwise se- ‘
45 cured to the inner wall of the cup near the lip. at its forward end, said ñange vbeing provided 45
with radial corrugations which taper into a
This ñange is corrugated, as shown, to permit smooth surface at its juncture with the wall, and
the lip of the cup to be slightly expanded by the a coiled expansible spring 4lying within the cylin
action of the expansible spring 24. A reinforce
drical wall and exerting a force vupon said flange
ment is provided in the bottom of the cup upon in a direction substantially parallel to the axis
50 which the spring seats. The lip of the cup is
50
_of the cup and at a distance from the wall.
ground to a circumference to snugly fit the cylin
_ 8. A packing member comprising a cup formed
der prior to assembly and release of the spring.
a flexible metal and ‘provided with aV ñared
The cup is then placed in the cylinder and the ' _of
open
end, an inwardly extending flange secured to
spring released, thus producing _a pressure be
55 tween the- edge of the lip and the wall in vthe _ the inner surface .of the open end ofthe cup, and
an expansible spring engaging the bottom of the
tion the lip 2l of the cup >22, is fla'red. An an
manner shown in Figure 5.
Having fully described my invention, vwhat I
claim as new and desire to secure by Letters
Patent of the United States is:
1
60
l. I'n fluid pressure apparatus, `.the combina- '
tion with a piston sealing cup of flexible material
provided with aninwardly extending flange ad
cup and the flange.
,
9. In a fluid compressor provided with a cyl
inder and a piston, a packing cup for the piston
provided with an inwardly extending flange' at its
forward end and araised surface on the bottom of ’o
its interior, a coiled'spring linterposed between
jacent -its lip, of means for increasing the contact
the base of the cup and the flange, and a dished
pressure of the lip of the cup on the cylinder
bottom, -said retainer being provided with a pe
05 wall, said means comprising a coiled spring hav
ing one end engaging the bottom of the cup and
the other end engaging the inwardly extending
flange on the cup adjacent its lip, and applying
pressure to the flange in a direction which is at
retainer engaging the raised surface of the cup '
ripheral groove forming a seat for the end of a 65
coil spring.
10. The combination of a piston and cylinder, a l
packing cup for the piston provided with a convex
70 an 'angle to a plane perpendicular to the cup axis. ' surface on the bottom of its interior, and a con
vex annular disc cooperating with the convex 70
2. In apparatus of the class described, a flexi
cup surface, said disc -being provided with a pe- .
ble packing cup provided with an inwardly ex
ripheral groove for seating the end of a coil
tending part'on its forward edge, and means for
forcing the edge of said cup radially outwardly,
75 said means comprising an axially. expansible
Spring.
v
«
'
BURNS Droz.
76
.
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