Pipe joints or couplings – Essential catch – Leaf spring
Reexamination Certificate
1999-07-16
2001-01-16
Arola, Dave W. (Department: 3627)
Pipe joints or couplings
Essential catch
Leaf spring
C285S423000, C285S906000, C285S921000
Reexamination Certificate
active
06173998
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a plug-in coupling for connecting two fluid conduits.
More specifically, the present invention relates to a plug-in coupling for connecting a first fluid conduit to a second fluid conduit, where the first fluid conduit has at least one retaining rib. The plug-in coupling includes a sleeve, which has radial openings. A cylindrical arresting device is axially guided for displacement within the sleeve. The arresting device has axially extending and elastically flexible retaining arms with a hook formed at the free end of the arms for engaging behind the retaining rib of the first fluid conduit when the first fluid conduit is axially introduced into the arresting device. The arms have at their free ends a radially outwardly inclined face, which, when the sleeve and the arresting device are moved axially apart into a locking position, presses against a front edge of one of the radial openings in the sleeve. Thus, the hook more firmly engages with the retaining rib when the arresting device and sleeve move axially away from each other. The arms also have at their free ends a radially inwardly facing inclined face that contacts the retaining rib when the arresting device and sleeve move axially away from each other. In an unlocking position, the arresting device is axially retracted into the sleeve such that the radially outer inclined face is sufficiently spaced from the front edge of the respective one of the radial openings in the sleeve to permit the retaining arms to spread radially apart due to the withdrawal movement of the retaining rib of the first fluid conduit. The arresting device has an unlocking arm disposed between each of the retaining arms. The unlocking arm has a radial outer part that projects radially outwardly, in an axially displaceable manner, through one of the radial openings in the sleeve. At least one sealing ring is disposed between an inner shoulder of the sleeve and the arresting device.
2. Discussion of the Related Art
A plug-in coupling is disclosed by German Reference DE 44 13 346 C1. The sleeve and the arresting or snapping device in the German '346 reference have to be moved axially relatively to one another by hand until the rear contact face of the unlocking arms lies against the rear edge of the respective hole through which the radially outer part of the respective unlocking arm projects outwardly. Without a more detailed explanation, the manner in which the unlocking arms have to be actuated to be moved into this unlocking position is not clear. Therefore, those unfamiliar with these unlocking arms, when attempting to release the coupling (e.g., for the purpose of repairing the device, or devices, connected to the fluid conduits), often only try to press the radially outwardly projecting parts of the unlocking arms radially inwardly, in a futile attempt to decouple the connection.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a plug-in coupling that easily permits an intentional decoupling of the connection.
According to a preferred embodiment of the present invention, this and other objects are achieved by using an arresting device that has unlocking arms. The unlocking arms have radially outer parts that a user will intuitively try to press together to decouple the connection. Because of engaging inclined faces between the unlocking arms and the sleeve, axial displacement of the arresting device into an unlocking position is effected by this pressing action.
Thus, in accordance with this solution, only the outer parts of the unlocking arms need to be pressed radially inwardly to achieve decoupling. After the unlocking arms are pressed inwardly, the user simply axially pulls apart the first fluid conduit, which has the retaining rib, from the plug-in coupling. This manner of decoupling the plug-in coupling is intuitive to most users, even those unfamiliar with the structural features of the present invention unlocking arms.
The unlocking arms preferably extend axially and are elastically flexible. Like the retaining arms, the unlocking arms have free ends that are hook-shaped. The unlocking arms, therefore, additionally serve as retaining arms. Thus, the unlocking arms increase the contact surface with the retaining rib via their hook-shaped free ends, thereby resulting in a firmer hold on the connection to prevent accidental or unintentional decoupling.
The unlocking arms each project radially outwardly through a radial opening in the sleeve. The unlocking arms also have a spring arm that extends axially away from the insertion opening of the sleeve. The spring arm has a first projection that projects radially inwardly. In an unlocking position, the arresting device is moved axially away from the insertion opening in the sleeve. To move the arresting device from the locking position to the unlocking position (i.e., by moving the retaining and unlocking arms back towards the rear edge of the radial openings), the spring arms are pressed radially inwardly causing first projection to engage a rear inclined face of a second projection on the outside of the sleeve. The inclined face is remote from the insertion opening of the sleeve.
To release or decouple the first fluid conduit from the arresting device, the spring arms are pressed against the sleeve to move the arresting device from the locking position to the unlocking position and so that the arresting device is fixed with respect to the sleeve. The arresting device is now in the unlocking position and is fixed with respect to the sleeve. The first fluid conduit can be pulled axially apart from the plug-in coupling, thereby causing the retaining arms to spread apart radially to separate the two fluid conduits.
In accordance with a further advantageous embodiment of the present invention, a radial outer part of each unlocking arm extends axially and has at the front end thereof a radially inner inclined face. In the locking position, the radially inner inclined face abuts against a radially outer inclined face of the sleeve. The radially outer inclined face is adjacent to a front edge of the opening that receives the outer part of the unlocking arm.
In this solution, the outer part of the unlocking arms only needs to be pressed radially inwardly to axially displace the retaining arms of the arresting device relative to the sleeve, into the unlocking position. If a radially inwardly directed pressure is applied by hand to the radial outer part of the unlocking arms, the radially inner inclined face of the unlocking arms slides along the radially outer inclined face of the sleeve, thereby causing the axial movement of the arresting device from the locking position into the unlocking position.
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patent: 5112086 (1992-05-01), Gruber et al.
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patent: 5167431 (1992-12-01), Maifredi
patent: 5284369 (1994-02-01), Kitamura
patent: 5320390 (1994-06-01), Kodama
patent: 5992895 (1999-11-01), Steinkamp
Arola Dave W.
Darby & Darby
Rasmussen GmbH
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