Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Threaded fastener locked to a discreet structure – Member or portion thereof located between substructure and...
Reexamination Certificate
2001-07-10
2003-02-11
Wilson, Neill (Department: 3679)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Threaded fastener locked to a discreet structure
Member or portion thereof located between substructure and...
C411S368000, C411S432000, C411S533000
Reexamination Certificate
active
06517301
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of co-pending German Patent Application No. 100 34 748.7 entitled “Lösbares Verbindungselement für ein Fahrzeug, mit einem Schraubteil und einem Stützring”, filed on Jul. 7, 2000.
FIELD OF THE INVENTION
The present invention generally relates to a detachable fastener assembly for a wheel of a vehicle. More particularly, the present invention relates to a fastener assembly which includes a screw element including a threaded portion and a supporting ring being rotatably connected to the screw element.
BACKGROUND OF THE INVENTION
Fastener assemblies including a screw element and a supporting ring are used to mount wheels to a hub of an axle of a vehicle. The screw element usually is a wheel bolt. However, it may also be a wheel nut also being associates with a supporting ring. In most cases, the supporting ring is captively connected to the screw element to facilitate assembly. The assembly is designed in a way that the supporting ring may not only be rotated with respect to the screw element, but the axes may also be dislocated with respect to one another in a radial direction within a predetermined play. However, this dislocation only takes place within a small region, as it, for example, makes sense to compensate dividing errors of the opening of the wheel rim and/or of the hub.
A detachable fastener assembly in the form of a wheel bolt is known from European patent application No. 0 836 016 A2. The wheel bolt includes a head and a shank including a threaded portion. The head of the wheel bolt at its side facing a supporting ring includes a supporting surface to transmit an axial force to the supporting ring. The supporting surface is designed as a plane surface. The supporting ring also includes a plane counter supporting surface being associated therewith. At its other side facing the vehicle, the supporting ring includes a non-planar bearing surface to transmit the axial force to the wheel of the vehicle. The bearing surface has a truncated cone design or a spherical design. The supporting ring is rotatably and captively connected to the wheel bolt by a calked surface. Usually, four calked surfaces are spaced apart over the circumference. The supporting ring is to be connected to the wheel bolt by the calked surface, and in a way that it may be turned with respect to the shank of the wheel bolt and that there is few friction between the supporting ring and the head of the screw when the wheels is affixed. The supporting ring may be made of a light metal alloy, whereas the wheel bolt is made of steel. In combination with the wheel of the vehicle being made of magnesium, an occurrence of contact corrosion between the supporting ring and the wheel of the vehicle is prevented. It may make sense to design the fastener assembly in a way that there only is few friction between the supporting ring and the screw head when the wheel is affixed. However, this low friction is disadvantageous with respect to unintentional loosening of the wheel bolts. With such known fastener assemblies, there is the special danger of unintentional loosening in case of transverse loads. This danger is especially important if one takes into account increasing engine power and vehicle weight. Consequently, the fastener assembly is subjected to substantial transverse loads during acceleration and braking. Additionally, there is the danger of such known fastener assemblies setting, especially due to unpreventable vibrations and oscillations prevailing at the vehicle. Thus, the axial force is reduced. In case of respective transverse loads, this leads to an evermore increased tendency of the known faster assembly to unintentionally loosen.
On the other hand, screws in which the supporting surface below the head has a special design to reduce the danger of unintentional loosening in case of loads are known. The supporting surface below the head includes a tooth arrangement including wedge shaped teeth. The tooth arrangement has a design in a way that the screw may be tightened comparatively easily due to slightly inclined surfaces of the tooth arrangement sliding over a component, while the teeth dig in the material of the component to be affixed after the tightening process has been finished and under prevailing load conditions. Consequently, this causes increased resistance which has to be overcome during loosening and unscrewing of the screw. The tooth arrangement desires a sliding movement of the supporting surface on the component when the screw is being tightened. On the other hand, during loosening and unscrewing, conditions requiring an increased loosening moment are desired to overcome a form-fit. The combination of the material of the screw and of the component has to be coordinated. It is to be understood that only the known screw includes a tooth arrangement, whereas the component has a plane or a flat supporting surface. In this way, unintentional loosening of the screw is usually prevented due to an increase of the friction between the supporting surface of the head of the screw and the respective counter surface of the component. On the other hand, intentional loosening of the screw by applying a respectively increased loosening moment is possible. A multiple use of such a known screw is limited.
Lock washer assemblies which are used in combination with a screw are known from German patent document No. 24 13 760, U.S. Pat. No. 3,263,727 and European patent document No. 0 131 556. The lock washer assemblies include two superposing washers which may have an identical design and which are supported on one another in a point-symmetric way. The two washers are located between the plane supporting surface being located at the head of the screw and the plane supporting surface being located at the component. The two washers at their outwardly facing surfaces, meaning the supporting surface facing the head, on the one hand, and the supporting surface facing the component, and the other hand, include a tooth arrangement which increases friction. The tooth arrangement includes a number of radial ribs or the like. The two washers at their sides facing one another each include a tooth arrangement including wedge shaped teeth. The tooth arrangements include inclined plane surface portions and possibly additional surface portions which are directed perpendicular with respect to the axis of the washer assembly and of the screw, respectively. The inclined surface portions are arranged at different inclination angles in the direction of the circumference to realize form-fit between the two washers when the screw is being tightened. When the screw is being rotated in the loosening direction, the respective wedge surfaces slide on one another in a way of an inclined plane to increase the axial force. During loosening or untightening of the connection, the increased axial force has to be overcome. The manufacture of such known washer assemblies is expensive, and the number of elements used for the connection is increased. In addition to the screw, the two washers have to be handled and, more importantly, they have to be mounted in the correct orientation. The washers are separate components which are not captive. The use of separate washers in combination with detachable screws has the further disadvantage of the number of parting lines and setting lines between the respective elements of the connection being increased. The greater the number of these lines is, the higher is the setting value of the connection caused thereby which results in a dangerous reduction of the axial force. This is especially the case when the elements used for the connection have a certain surface design, for example a coating reducing corrosion or the like, and when these elements are subjected to increased temperatures during operation. It is to be understood that such known separate washer assemblies are not suitable as detachable fastener assemblies for the attachment of the wheel of a vehicle since the respective bearing surface at the wheel rim has a conic
Hartmann Gunther
Sommer Wolfgang
Wagner Frank
Kamax-Werke Rudolf Kellermann GmbH & Co. KG
Thomas Kayden Horstemeyer & Risley
Wilson Neill
LandOfFree
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