Receptacles – Closures – Magnetic
Reexamination Certificate
1999-12-10
2001-03-27
Castellano, Stephen (Department: 3727)
Receptacles
Closures
Magnetic
C220S304000
Reexamination Certificate
active
06206219
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to an apparatus for monitoring the closed position of a locking gas cap, with a magnet disposed at or in the locking gas cap and a magnetic switch disposed at the tank connection pipe.
An apparatus of this type is described in the DE 44 04 014 A1 and serves to monitor the closed position of the locking gas cap of a motor vehicle so that, when the locking gas cap is not closed or closed incompletely, a warning signal appears on the dashboard of the vehicle.
In the case of the known apparatus, the locking gas cap has a bayonet catch and the magnet is disposed in such a manner, that it is in the vicinity of a reed switch, when the bayonet catch is locked. Depending on the construction, the reed switch is thus either open or closed when the locking gas cap reaches the locked position. Preferably, the reed switch is constructed so that it is closed in the locked position and that an associated evaluating circuit causes a warning signal to be displayed when the circuit of the reed switch is interrupted.
Since the magnetic field of the magnets cannot be localized to a narrow limited space, the position of the locking gas cap can be determined only relatively inaccurately according to this principle. For many tank caps, the locking gas cap is constructed as a screw-in plug. However, even in the case of bayonet-like tank caps, screw pitch surfaces are usually provided, which ensure that the plug, in the closed position, is pressed firmly against an associated seal. The possibility therefore exists that the locking gas cap is not turned completely into the end position, in which the tank opening is sealed reliably and in which a subsequent loosening of the locking gas cap due to vibrations is prevented because of the frictional engagement. However, because of the aforementioned inaccuracy in determining the position, the reed switch would also respond in such a case, so that the correct closing of the locking gas cap cannot be indicated reliably.
SUMMARY OF THE INVENTION
It is an object of the invention to make it possible to monitor the closed position of the locking gas cap with greater reliability.
Pursuant to the invention, this objective is accomplished owing to the fact that the locking gas cap has a torque limiter and the magnet is coupled with the torque limiter in such a manner, that it reaches a position, in which the magnetic switch is triggered, only when the limiting torque is attained.
By these means, it is ensured that the magnetic switch responds only when, while screwing in the locking gas cap, the limiting torque is actually reached and it is thus ensured that the locking gas cap is effectively closed tightly and completely.
A locking gas cap with a screw-in plug and a torque limiter is described already in DE 196 10 471 C2. This locking gas cap has a cap, which is rotatably disposed on the screw-in plug and is provided with a handle. The torque, which is exerted by the user on the cap, is transferred by the torque limiter to the screw-in plug. As soon as the limiting torque is exceeded when the closed position is reached, the cap rotates relative to the screw-in plug. In accordance with an advantageous development of the present invention, this relative movement is used for the purpose of transferring the magnet into the triggering position. Preferably, the magnet is held axially movable in the locking gas cap and, at the cap or at the plug of the locking gas cap, inclined surfaces are provided, which convert the rotation of the cap relative to the plug into an axial motion of the magnet. The magnet is pre-stressed elastically in the position at rest and is converted into the release position only when the limiting torque is reached by the inclined surfaces. At the same time, the inclined surfaces and the associated mating surfaces can be constructed in such a manner, that they can slide off one another when the cap is rotated further after it has reached the limiting torque. In this case, it is possible that the magnet springs back once again after it has exceeded the limiting torque and is removed from the release position. Preferably, this spring-back motion is, however, limited so that the magnetic switch, because of the magnetic remanence of the reed contacts, nevertheless remains closed. Only when the locking gas cap is loosened once again or removed completely, does the distance between the magnets and the magnetic switch become so large that the switch opens up. In this case, therefore, the magnetic switch exhibits some hysteresis behavior. It closes only when the limiting torque is reached or exceeded at least once, but then remains closed when the magnet once again is removed further from the magnetic switch.
Alternatively, an embodiment is also conceivable, for which the magnet, in the release position, is relatively close to a magnetizable body, so that, upon reaching the release position, it is held magnetically in the release position and springs back once again into the position at rest only when it is screwed out of the locking gas cap.
REFERENCES:
patent: 3986634 (1976-10-01), Smith et al.
patent: 4065026 (1977-12-01), Williams et al.
patent: 4223799 (1980-09-01), Eyster et al.
patent: 4957266 (1990-09-01), Ellis
patent: 5110003 (1992-05-01), MacWilliams
patent: 5975328 (1999-11-01), Hagano et al.
patent: 4404014 (1995-08-01), None
patent: 19501797 (1997-03-01), None
patent: 19610471 (1997-10-01), None
patent: 2168961 (1986-07-01), None
Adwest Kohler GmbH
Castellano Stephen
Goldberg Richard M.
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