Two-piece check valve assembly

A two-piece check valve device comprising a rubber sealing element and a plastic carrier member. A through bore in the plastic carrier member receives the sealing element, which is formed with an annular groove in which the carrier member is removably secured. The through bore and annular groove may be correspondingly tapered to facilitate assembly and disassembly of the check valve device.

BACKGROUND OF THE INVENTION 
The present invention relates to check valves and particularly to poppet 
type check valves such as are typically employed in pneumatic brake 
control valve devices for railroad vehicles. 
Poppet type check valves generally comprise a valve element that moves 
perpendicularly relative to a seat to open and close a fluid conducting 
passageway in which the valve element and seat are situated. When used as 
a backflow check, the valve element is arranged to disengage its valve 
seat in response to fluid flow in a desired direction and to engage its 
valve seat in response to fluid flow in the opposite direction. 
Alternatively, a piston actuator may be employed to operate the check 
valve element in a direction to engage or disengage its valve seat. 
One such poppet type check valve known in the prior art is shown in FIGS. 1 
and 2 of the drawings and is commonly employed in the aforementioned 
pneumatic brake control valve devices. The valve element A of such poppet 
type check valves is typically made from a rubber compound that is bonded 
during a molding process to a stamped metal insert B to form a unitary 
valve structure. The metal insert gives rigidity to the rubber valve 
element and provides a fluted guide C that is adapted to engage the 
passageway in which the check valve is disposed. The flutes are designed 
to permit fluid to pass around the solid molded structure and to maintain 
proper alignment of the valve element with its seat. 
In the manufacture of these insert-molded, unitary poppet type check 
valves, difficulty is encountered not only in the molding process itself, 
but also in the after-molding process of removing flashing produced during 
the molding operation. In addition, such a unitary valve structure 
requires replacement of the entire check valve, including the metal 
insert, when the rubber valve element becomes worn. 
SUMMARY OF THE INVENTION 
It is therefore an object of the present invention to provide a new, poppet 
type check valve device that is simple to manufacture and low in cost. 
It is an extension of the foregoing to provide a check valve device that 
requires no bonding of the rubber valve element to a metal insert or the 
like. 
Another object of the invention is to provide a two-piece check valve that 
permits replacement of either piece independently of the other. 
Still another object of the invention is to employ a plastic carrier with 
which the rubber valve seal element is arranged in a two-piece assembly. 
These objectives are carried out by means of a two-piece, snap-together 
check valve device that permits individual molding of the separate check 
valve components, which makes a simpler, less costly molding operation, 
such as injection molding, possible. The rubber valve seal element is 
designed to be retained in a separate plastic carrier member so that it 
can be removed therefrom and replaced when worn. The carrier member has a 
through bore in which the rubber seal element is removably secured by 
engagement with an annular groove in the body of the seal element. The 
carrier member has a fluted periphery that guidably positions the check 
valve device in its passageway without cocking, in order to ensure the 
integrity of the check valve seal when engaged with its seat and to permit 
passage of fluid around the periphery of the check valve. The ability to 
individually mold the separate check valve components affords greater 
design latitude and consequently enhances the cost effectiveness of the 
check valve device according to the present invention.

DESCRIPTION AND OPERATION 
In each of the various embodiments herein disclosed, there is provided a 
segmented check valve device 10 comprising a rubber seal element 12 and a 
plastic carrier member 14, for which a glass-filled nylon is the preferred 
material. 
In the preferred embodiment of the invention, as shown in FIGS. 3 and 4, 
seal element 12 is formed by a rubber body portion 16 having a head 18, an 
annular shoulder 20 that extends laterally from head 18, and a bulbous 
shaped bottom end 26. The upper surface 22 of shoulder 20 provides a 
sealing area with which a valve seat (shown in phantom) of a poppet valve 
assembly is engageable. In the case of the tapered style seat represented, 
the sealing area is generally the edge of shoulder 20 between the upper 
surface 22 and its periphery 24. 
Formed in the periphery of body portion 16 between the underside 25 of 
shoulder 20 and bulbous bottom end 26 is an annular groove 23 in which 
carrier member 14 is retained. The base of groove 23 is tapered such that 
the diameter is smaller at bulbous end 26 than at shoulder 20. The bulbous 
end 26 of body portion 16 has an opening 32 that extends inwardly a 
distance at least beyond bulbous end 26 to provide flexure of bulbous end 
26 in order to facilitate insertion of seal element 12 into carrier member 
14 and subsequent removal therefrom. 
Carrier member 14 is formed with a bore 34 and a counterbore 36, bore 34 
having a taper conforming to the taper of groove 23 in body portion 16. 
Seal element 12 is assembled with carrier member 14 by inserting bulbous 
end 26 of body portion 16 into tapered bore 34, at the larger diameter 
thereof, until the bulbous end enters counterbore 36. The diameter of 
bulbous end 26 is greater than the smaller diameter of tapered bore 34, 
such that the bulbous end flexes inwardly during insertion just before 
entering counterbore 36, the diameter of which is greater than the 
diameter of bulbous end 26 to permit the flexed bulbous end to expand to 
its normal unflexed condition. In this manner, the assembly of seal 
element 12 with carrier member 14 is fixed or locked by engagement of the 
underside 25 of shoulder 20 with an upper surface 38 of carrier member 14, 
and by engagement of bulbous end 26 with a lower surface 39 of carrier 
member 14 formed by the base of counterbore 36. 
The relatively large mass of seal element 12 combined with the relatively 
large support area of the tapered through bore of carrier member 14 
provides such rigidity as to prevent distortion of seal element 12 under 
load, without requiring a metal insert, as employed for such purpose in 
the prior art practice. In addition, the taper of through bore 34 
accommodates insertion of bulbous end 26 of seal element 12 into carrier 
member 14 without interference therebetween until the seal element 
approaches final insertion, thus making assembly easy. 
Carrier member 14 is further formed with a fluted periphery 40 that is 
sized in accordance with the diameter of the passageway in which the check 
valve device is disposed, in order to provide a guide for alignment of the 
check valve device with its seat and to permit generally unrestricted flow 
of air past the guide when the check valve device is unseated during 
operation. An annular recess 42 in the bottom surface of carrier member 14 
provides a seat to accommodate a spring when such is employed to bias the 
check valve device toward engagement with its seat. In this preferred 
embodiment of the invention, the shoulder 20 of seal element 12 is absent 
any support at its periphery, since such design is intended for use with a 
tapered type seat, as represented by the dot-dashed lines in the drawing. 
During engagement with seal element 12, the tapered seat tends to 
laterally contain the seal so as to not require any peripheral support. 
In the event seal element 12 becomes worn or damaged, it can be removed 
from its assembly with carrier member 14 by inserting a blunt nosed tool, 
for example, into opening 32 with sufficient force to cause bulbous end 26 
to flex inwardly and thereby release its locking engagement with the base 
39 of counterbore 36. In this manner, the worn or damage seal element may 
be removed from carrier member 14 and replaced with a new seal element, 
without requiring replacement of the carrier member. 
In an alternate embodiment of the invention shown in FIGS. 5 and 6, a check 
valve device 110 is shown, which is intended for installations requiring a 
more compact check valve design than the embodiment of FIGS. 2 and 3; and 
also for such installations in which a vertically disposed valve seat is 
employed instead of a tapered valve seat as in the embodiment of FIGS. 2 
and 3. 
Check valve device 110 differs from check valve device 10 in that tapered 
groove 123 of body portion 112 is shorter in length than groove 23, and 
the periphery of carrier member 114 is arcuate and surrounds the periphery 
124 of shoulder 120. In shortening tapered groove 123 in body portion 112, 
a more compact design is realized for installations where space 
limitations exist. In addition, carrier member 114 is formed with a recess 
115 in its top surface into which tapered bore 134 opens. When seal 
element 112 is inserted into carrier member 114, shoulder 120 of seal 
element 112 is retained within recess 115 such that the periphery of 
carrier member 114 surrounds the periphery 124 of shoulder 120 in order to 
prevent lateral displacement and distortion of the seal element during 
seat engagement. The fluted periphery 140 of carrier member 114 is further 
shaped arcuately to guide the check valve device 110 in its bore without 
binding and cocking, as the carrier member of this design is inclined to 
do because of its relatively thin size and to permit passage of fluid. 
Another alternate embodiment of the invention is shown in FIGS. 7 and 8, in 
which check valve 210 differs from the previous embodiments by reason of 
annular groove 223 being non-tapered and by the absence of a bulbous 
shaped bottom end of seal element 212. In this embodiment, the annular 
groove 223 in body portion 216 is formed between the underside 225 of 
shoulder 220 and a spaced-apart, confronting side 228 that is generally 
parallel to underside 225. As opposed to the tapered annular groove 23, 
123 of body portion 12, 112 in the previous embodiments, the periphery of 
body portion 216 within groove 223 in this embodiment is normal to sides 
225 and 228 and is thus not tapered. Neither, therefore, is the 
correspondingly shaped bore 234 in carrier member 214 tapered. It will be 
appreciated that a tapered retention area of body portion 212 and 
correspondingly tapered bore of carrier member 214 are unnecessary in this 
design, due to the relatively short distance the seal element 212 needs to 
be inserted to realize locking assembly with the relatively thin carrier 
member 214. 
While the annular groove of body portion 216 is non-tapered, the area 
between groove 223 and bottom 226 is tapered. The purpose of this taper, 
in conjunction with the opening 232 in body portion 216 is to ensure 
sufficient flexure of body portion 216 to facilitate insertion of seal 
element 212 into carrier member 214 during assembly therewith and 
subsequent removal therefrom.