Receptacles – Closures – Removable closure guided in rotary movement
Reexamination Certificate
2000-03-10
2001-04-03
Newhouse, Nathan J. (Department: 3727)
Receptacles
Closures
Removable closure guided in rotary movement
C220S293000, C220S375000, C220SDIG003
Reexamination Certificate
active
06209746
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a tank cap for the fuel tank of a vehicle, which seals the fuel tank from the exterior of the vehicle unless the tank cap is opened for the purpose of, for example, adding fuel. More particularly, the invention relates to a tank cap having features which optimize space requirements and which enhance manufacturability and improve the safety of the finished, installed product.
Conventional tank caps for closing the filler neck of a vehicle fuel tank usually include a closure member for closing the mouth of the filler neck and a handle or cap element which moves relative to the closure member to permit a user to install or remove the tank cap. It is known to provide tank caps that can be inserted and removed without having to rotate the cap for through multiple 360° rotations. It also is known to provide a tank cap that is installed or removed with less than a full 360° rotation. This feature not only is convenient to the user, but a tank cap with an angle of free travel that is something less than 360°, e.g., a angle in the range of between 90° and 270° and preferably 180°, is less likely to become dislodged to expose the fuel tank in the event of an accident when the body of the vehicle is impacted or deformed. Owing to the free travel feature, even when something is forced onto the cap element of the tank cap in a substantially linear movement, the cap element will rotate or give to some degree without the result of dislodging the tank cap from the filler neck of the tank and, thus, a hazard is avoided that otherwise would be presented by escaping fuel. In some countries, automobile manufacturers are required by law to provide tank caps characterized by an angle of free travel.
U.S. Pat. No. 5,794,806 discloses one manner of implementing a free travel feature. This tank cap has a return spring, configured as a torsion spring, between the cap element and the closure element which is attached at its corresponding ends to rotate in unison on the cap element and on the closure element. During assembly of the two components, the untightened return spring initially is inserted into one of the two components and the other component then is positioned on the component into which the spring has been inserted. The spring tension that occurs when the cap element is rotated relative to the closure element is bounded by reason of a first stop, against which the cap element is held, and a second stop, which limits the maximum angle of free travel through which one of the components can rotate with respect to the other.
This implementation of the free travel feature can result in a less than optimum design, however, because in this tank cap the torsion spring is arranged in a plane that is perpendicular to the plane of rotation of the cap element. Thus, the tank cap must be long enough or tall enough to accommodate the length or height of the spring. A tank cap of the type disclosed in U.S. Pat. No. 5,794,806 also can be difficult to assemble and to subsequently inspect. For example, assembly of such tank caps frequently still is accomplished manually, and it is possible for the spring to be incorrectly inserted during assembly, such that the spring force will act in the opposite, and therefore in precisely the wrong, direction.
If an error is made in the assembly of a tank cap of this type, the error can prove to be difficult to detect, because both components nevertheless still are rotatable with respect to each other, albeit in the direction from the second stop to the first stop rather than in the correct direction from the first stop to the second stop. The rapid check that usually is performed in the course of industrial mass production of tank caps is not likely to reveal this sort of error, and the problem is not likely to be discovered until an attempt is made to install the tank cap to seal the filler neck of the fuel tank. Efforts to more thoroughly inspect the tank cap at the time of assembly of the cap element and the closure element would increase the time required for the inspection, as the inspector necessarily not only would have to check whether the cap element is rotatable under a spring load, but also whether the direction of rotation is the proper direction.
What has been needed and heretofore unavailable is a tank cap that is designed to make efficient use of space and can be manufactured cost effectively, that can be installed with the least possible risk of error, and that subsequently can be timely and easily inspected in order to detect any assembly errors which do occur. The present invention satisfies these needs.
SUMMARY OF THE INVENTION
The present invention is directed to a tank cap including a cap element which is free to move through an angle of rotation or an angle of free travel with respect to a closure element by reason of a return spring, which return spring is arranged between the closure element and the cap element such that the longitudinal axis of the return spring lies in a plane that intersects the axis of rotation of the tank cap, and the return spring further is arranged at an angle to the axis of rotation on the cap element.
This return spring, which can be a tension spring or a compression spring, correctly is installed under tension or compression and, as such, it is not feasible to install the spring such that it has an incorrect direction of spring force. Thus, the installation can be checked easily and quickly, because there are only two possible conditions. That is, the assembly either exhibits spring tension (correct assembly) or it exhibits no spring tension (incorrect assembly). Unlike tank caps of the prior art, in which the springs can be assembled such that the spring force will act in the wrong direction, inspection of a tank cap according to the present invention can be restricted to testing whether spring loading actually is present.
The return spring can be arranged at any angle relative to the axis of rotation of the cap element, but is preferably arranged in a plane perpendicular to the axis of rotation, i.e., the return spring is arranged in the plane of rotation of the cap element or a plane that is parallel to it. A perpendicular plane is understood here to mean a plane that is intersected by the axis of rotation at a right angle. The return spring can be any type of spring that can store and release tensile or compressive forces. A simple coil spring or a rubber spring is preferred.
The spring force necessary need not be very great, because the force must only be sufficient to return the unstressed tank cap to its resting position. Thus, the diameter of the spring can be kept small and therefore the space requirements are not excessive in the direction of the axis of rotation of the cap element. The amount of space that the return spring requires in the transverse direction may be greater than the amount of space that is required with torsion springs which are disposed in a plane that is perpendicular to the plane of rotation, however, this is not a design concern because there is sufficient space available in this direction anyway.
The closure element to be used in the filler neck preferably is designed to be rotationally symmetric, however deviations from this design also are contemplated. The cap element can be pivotally attached to the closure element by a pivot pin at the center of the closure element which pivot pin is received by a receiving hole in the center of the cap element. The return spring, which desirably is a tension spring, is guided in at least the tightened state in a more or less circular arc around the pivot pin.
Under some circumstances, disposing a spring about a pivot pin in such manner might result in restricting the number of effective windings of the spring due to friction force. In order to avoid rendering ineffective any of the windings of the spring due to friction force, a deflection sleeve preferably is provided. The deflection sleeve has a center hole through which the pivot pin can extend, and the return spring is guided around the per
Fulwider Patton Lee & Utecht LLP
Gerdes GmbH
Newhouse Nathan J.
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