Pipe joints or couplings – With means blocking release of holding means
Reexamination Certificate
2001-04-19
2002-09-10
Nicholson, Eric K. (Department: 3679)
Pipe joints or couplings
With means blocking release of holding means
C285S312000, C285S085000, C285S087000
Reexamination Certificate
active
06447016
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
Not Applicable
BACKGROUND OF THE INVENTION
This invention relates to the general field of quick disconnect couplings known as Cam & Groove couplings for hose and pipe. Cam & Groove couplings have been in common use for many years as quick disconnect coupling joints for hose and pipe involved in fluid transfer. Cam & Groove couplings consist of a male and a female type coupling. Both male and female couplings are tubular in nature and attach to the ends of hose or pipe for the purpose of connecting and disconnecting the lengths of hose or pipe. Together the two couplings comprise a quick disconnect coupling joint.
The male coupling is constructed with a radial groove around its exterior perimeter. The female coupling is constructed with an interior diameter large enough to accept the insertion of the male coupling into the female coupling's interior. An integral aspect of the female coupling is pivoting cam arms mounted onto the female coupling.
The cam arms are located between two lugs, known as ears. There are two sets of ears on each female coupling; each set is on opposite sides of the coupling body, 180° apart. Each set of ears contains one cam arm assembly. The cam arms pivot on a steel pin between the ears and retain the male coupling inside the female coupling when the cam arms are in the closed position.
Since the integrity of the coupling joint is dependent upon the movement of the cam arms, considerable effort has been employed to devise methods of retaining the cam arms in a closed position to prevent unintentional opening and allowing the coupling joint to become uncoupled. Wire safety clips are used for this purpose and are standard on all major brand couplings. The wire safety clips are inserted by the operator through holes in the female coupling in such a manner so that the wire clip is positioned on the outside of the cam arms where they become an obstruction to the opening arc of the cam arm and prevent the cam arm from opening. This method of retaining the cam arm in the closed position is an active action, requiring the operator to perform the additional task of inserting the clips. A passive method of cam arm retention is preferred, which does not require the operator to take any additional action to ensure that the cam arms can not be unintentionally opened.
U.S. Pat. Nos. 6,015,168 and 5,435,604 and 5,295,717 address the issue of passive cam arm retention in Cam & Groove couplings. These inventions utilize a locking member housed by various methods, inside the cam arm. The locking member in the cam arm interacts with a mating member on the female coupling to accomplish the task of locking the cam arms in the closed position. The locking member located inside the cam arm is attached to the cam arm finger ring. The finger ring is used to release the lock so that the cam arm can be opened. While these inventions work effectively, they have a number of shortcomings.
The most significant shortcoming is that the releasing of the locking mechanism and the opening of the cam arm are both accomplished by a pulling force applied to the finger ring. The same pulling force applied to the finger ring releases the locking mechanism and opens the cam arm. This arrangement can lead to accidental openings of the cam arm. Cam & Groove couplings are widely used in industrial applications with a large percentage of use as hose quick disconnects. The hose assemblies are subject to severe conditions from handling, moving, dropping and otherwise hard service. In situations where hose assemblies are used on the ground, an object can snag the finger ring and hold it firm while the hose assembly is moved thus releasing the locking mechanism and possibly opening the cam arm.
Another shortcoming of the fore mentioned inventions is the dependence on the cam arm finger ring to perform the task of releasing the locking mechanism. The cam arm finger ring is subject to possible impairment, due to the harsh environments to which this type of coupling may be subjected. The finger ring can become damaged, lost or removed, making it difficult to release the locking mechanism.
Still another shortcoming of the fore mentioned inventions is that they have a mating member on the female coupling that the locking mechanism inside the cam arm engages with to retain the cam arm in the closed position. This mating member is cast as an integral part of the female coupling and extends out from the body to protrude into the space normally occupied by a standard cam arm handle. While this arrangement is satisfactory when the specialized locking cam arm designed for that particular brand coupling is used, it is not functional with a standard generic cam arm. The protruding mating member on the female coupling will obstruct and block the rotation needed to complete the closing cycle of a standard generic type cam arm. Should the specifically designed locking cam arm become damaged, jammed or otherwise nonfunctional, a replacement cam arm of the same specialized design must be obtained to restore the coupling to service. Therefore, a standard generic cam arm readily available from numerous sources, will not return the hose assembly to temporary use until a suitable replacement cam arm can be obtained from a specific manufacturer.
SUMMARY OF THE INVENTION
It is the object of this invention to provide a passive locking mechanism for the cam arms on a Cam & Groove coupling without utilizing the finger ring as an integral aspect of operation.
It is another object of this invention to provide a passive locking mechanism for the cam arms on a Cam & Groove coupling that would allow for the removal of said locking mechanism and the substitution of a standard generic cam arm assembly, in the case of emergency field repair.
The present invention is a female Cam & Groove coupling with self locking cam arm assemblies. Each cam arm assembly contains a pivotal locking latch mounted onto the exterior of the cam arm. During the closing cycle of the cam arm, the latch interlocks with the female coupling body in such a manner as to prevent the unintentional opening of the cam arm. The locking latch is self-locking on the closing cycle of the cam arm and manually released by an intentional and secondary action applied by the operator on the opening cycle of the cam arms.
An additional feature of this invention is that in the event the locking cam arm assembly becomes damaged beyond functionality, the entire locking cam arm assembly can be completely removed from the coupling body and replaced with a standard generic cam arm assembly. The female coupling will continue to be operational as a standard Cam & Groove coupling without the passive locking features. As there are no obstructing members on the female coupling body to interfere with the operation of a standard generic cam arm assembly, the female coupling can be emergency field repaired and continue to be of service.
Still another feature of this invention is the optional use of a wire safety clip. Even though the use of a wire safety clip is in common use in today's market as a device for cam arm retention, the combination of a wire safety clip and a passive locking cam arm assembly is not common and further enhances this invention.
REFERENCES:
patent: 3124374 (1964-03-01), Krapp
patent: 4295670 (1981-10-01), Goodall et al.
patent: 4647075 (1987-03-01), Vargo
patent: 4802694 (1989-02-01), Vargo
patent: 5295717 (1994-03-01), Chen
patent: 5435604 (1995-07-01), Chen
patent: 5816623 (1998-10-01), Chang
patent: 5911445 (1999-06-01), Lee
patent: 6015168 (2000-01-01), Fahl
patent: 6047995 (2000-04-01), Kotake
patent: 6053540 (2000-04-01), Meyer
patent: 6224133 (2001-05-01), Abramoski et al.
National Equipment Corp.
Nicholson Eric K.
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