Expanded – threaded – driven – headed – tool-deformed – or locked-thr – Threaded fastener locked to a discreet structure – Fastener – or coaxial adjunct therefor – having sidewardly...
Reexamination Certificate
1999-11-22
2001-11-27
Saether, Flemming (Department: 3627)
Expanded, threaded, driven, headed, tool-deformed, or locked-thr
Threaded fastener locked to a discreet structure
Fastener, or coaxial adjunct therefor, having sidewardly...
C411S120000, C411S234000, C081S013000
Reexamination Certificate
active
06322306
ABSTRACT:
TECHNICAL FIELD
The invention relates to fastening mechanisms and, in particular, to external secondary locking mechanisms to prevent the relative rotation and loosening of various separable connectors or fasteners, most commonly threaded connectors or fasteners.
BACKGROUND OF THE INVENTION
The secondary locking mechanisms to prevent the relative rotation and loosening of various separable connectors or fasteners have been developed over a long period of time, and different types of mechanisms have been created for various applications. In aerospace applications, anti-rotation features are important and external secondary locking mechanisms are widely used in different structures. In an assembly of rotating equipment such as gas turbine engine fans, for example, there are occasions where blind assembly of bolts would be required. In such situations, the head of the bolt cannot be reached at the time that components to be joined are installed, when applying a nut, or when tightening a nut. Various clips and retaining means are known to retain a bolt at such time. In other situations, external secondary locking mechanisms are used for locking connectors that join tubes, hoses and wiring together or to an accessory unit. The requirements for aerospace applications are particularly stringent, in particular, for use on engines, hydraulic systems, fuel systems and electrical cable connectors. The current and most common means for secondary locking of aerospace connectors or fasteners are lock wires and safety wires which require special features to be incorporated in the connectors or fasteners. Other means comprise crimp nuts, fibre nuts and tab washers. These external locking devices may permit some small relative rotation of the connectors or fasteners, and usually are destroyed or rendered non-reusable in aerospace applications, once unlocked to open the connectors or unfasten the fasteners.
With high speed rotating equipment, high stresses are formed and notches, scratches or plastic deformation forms stress concentrations. Any such stress concentration can cause failure during the operation of the apparatus. It is therefore desirable that any external secondary locking mechanism not require a basic component design having a substantial stress concentration. Lightweight is also important in such high-speed rotating equipment and, accordingly, a lightweight, simply construed secondary locking mechanism is desired. Efforts have been made to improve external secondary locking mechanisms in aerospace applications and one example is shown in U.S. Pat. No. 5,350,201, entitled SEPARABLE CONNECTOR EXTERNAL CAPTURE DEVICE and issued to K. K. Bynum on Sep. 27, 1994. Bynum describes an external capture device having two co-axial spring clips sized to tightly grip the external surfaces of the separable connector to be secured. Each clip is a semi-circular spring band and serrated in form and joined by an axial bar. In another example, Dimmick III et al. describe in U.S. Pat. No. 4,887,949, which is entitled BOLT RETENTION APPARATUS and issued on Dec. 19, 1989, a retention clip co-operating with a bolt and a flange through which the bolt passes to retain the bolt during blind assembly.
SUMMARY OF THE INVENTION
One object of the invention is to provide an anti-rotation clip which is simply constructed and easy for use.
Another object of the invention is to provide an anti-rotation clip which can be used for two or more separable connectors or fasteners in an assembly to prevent the same from rotation relative to one another or to a body which supports the connectors or fasteners.
In accordance with one aspect of the invention, there is provided an anti-rotation clip device which comprises:
at least one clip made of a spring band forming a circular and circumferentially discontinuous annulus having a circumferentially open portion of less than 180°, adapted to radially and forcibly grip a polyhedral element of a first object when the polyhedral element is laterally and forcibly captured therein, through the circumferentially open portion of the clip; and the clip having a first tang member fixed to the clip, the tang member including a laterally and inwardly facing end, the end being flat along substantially its entire face, adapted to abut a flat surface on a body to which the first object is rotatably connected so that relative rotation between the first object and the body is inhibited.
The first tang member preferably extends from the spring band and the flat end of the tang member is adapted to be received in a groove having a flat bottom on the body to prevent the first object from rotation and the device from axial movement relative to the body.
In an embodiment of the invention, it is preferred that the spring band include a second tang member which is similar to the first tang member and diametrically opposed to the first tang member, and adapted to engage a second groove having a flat bottom on the body to ensure the prevention of the object from rotation and the device from axial movement relative to the body.
In another embodiment of the invention, the anti-rotation clip device includes two spaced apart clips co-axial about a common axis. Each of the clips is a circumferentially discontinuous annulus, forming a circular and circumferentially open portion of less than 180°. A polyhedral element of either one of two objects in an assembly can be laterally and forcibly captured through the open portion of a corresponding one of the clips, and each clip is enabled to radially and forcibly grip the polyhedral element. Each clip is made of a spring band with two ends bent outwardly to facilitate the insertion of the polyhedral element of the object. A connection bar formed integrally with the spring bands rigidly interconnects the two clips at their middle portions so that relative rotary and linear movement between the two clips are restrained. Two tang members fixed to and axially spaced apart from one of the open clips are diametrically opposed and symmetrical about the connection bar. Each tang member includes a laterally and inwardly facing end, the end being flat along substantially its entire face, adapted to abut a flat surface on a body to which the respective objects are rotatable connected so that relative rotation between each object and the body is inhibited. Furthermore, two sides of each tang member are adapted to co-operate with two corresponding surfaces on the body to prevent the device from axial movement relative to the body.
In accordance with another aspect of the invention, an anti-rotation clip includes at least two spaced-apart clips co-axial about a common axis, each clip being a circular and circumferentially discontinuous annulus, forming a circumferentially open portion of less than 180°. A polyhedral element on either one of two objects which are threadedly connected to a body respectively can be laterally and forcibly captured through the open portion of a corresponding one of the clips. Each clip therefore is enabled to radially and forcibly grip the polyhedral element. Each clip is made of a spring band with two ends bent outwardly to facilitate the forcible insertion of the polyhedral element on the object. A connection bar formed integrally with the spring bands rigidly interconnects the two clips at their middle portions to restrain relative rotary and linear movements between the two clips so that the two objects which are rotatable relative to each other are prevented from relative rotation when they are forcibly gripped by the respective clips. At least one pair of axially spaced apart tang members are fixed to either side of the connection bar between the two clips and enabled to axially restrain within a space therebetween a flange member on the body so that the device is prevented from axial movement relative to the objects.
No special tools are required for the anti-rotation clip device to be added to or removed from a closed connector, or a fastener assembly. The secure attachment of the clip device is ensured by the resilient force. There is
Astle Jeffrey W.
Pratt & Whitney Canada Corp.
Saether Flemming
LandOfFree
Anti-rotation clips does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Anti-rotation clips, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Anti-rotation clips will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2611617