Monogram Aerospace Fasteners, Inc.

Northrop Corporation

Mag Aerospace Industries, Inc.

Monogram Aerospace Industries, Inc.

Edgar L Stencel

Paul P Krawiec

A blind fastener for clamping sheet components and including a mechanical lock to prevent loosening of the fastener. The fastener is self-expanding following insertion and engagement of the threaded stem. The fastener includes an internally threaded nut body, an externally threaded stem threadably received within the nut body, and a lock sleeve matingly receiving the nut body. Carried on the stem is an expandable sleeve which expands to engage the underside of the material. Rotation of the stem following insertion of the assembly into the aperture will draw the stem head and expandable sleeve against the backside for the material causing the sleeve to expand outwardly. In addition, the locking sleeve is pushed beneath the expansion sleeve wedging between the threaded stem and expansion sleeve. This mechanical lock is resistant to vibration locking the fastener against loosening.

Self-expanding blind fastener with mechanical lock

A blind fastener having a body, a core bolt, a nut and a sleeve. The core bolt passes through an axial bore of the body and includes an externally threaded portion at an inner end thereof. The nut has an enlarged head, a reduced diameter stem and a threaded bore for engaging the threaded portion of the core bolt. The sleeve is located between the enlarged head of the core bolt and a conically shaped inner portion of the body. An inner end portion of the sleeve is fixed to the stem of the nut. In a preferred embodiment, the inner end portion of the sleeve is crimped to the nut and has a thickness sufficient to engage the nut across the full width of an annular shoulder of the nut during setting of the fastener.

Blind fastener with deformable sleeve

A threaded fastener that self locks as it is tightened to a fastened object. The thread includes one or more portions that are shifted, resulting in one or more discontinuities in the thread. Each shifted portion of thread is fully formed at the discontinuity. The shifted portions will deform a relatively softer female thread, causing the deformed thread to move up and over the end faces of the shifted portions and to pack up in front of the end faces to prevent any significant loosening of the connection.

Die set for forming a fastener with thread lock

An insert assembly for installation in a workpiece having a threaded hole. When the inner insert is axially received within the outer insert, the mating surfaces of these members are configured such that the inner insert applies a radial outward force to the outer insert to securely install the insert assembly in the workpiece. A stud assembly also is provided for installation in the workpiece hole. The stud assembly comprises a stud body and a stud. When the stud is axially received within the stud body, the mating surfaces of these members, like the insert assembly, are configured such that the stud applies a radial outward force to the stud body to securely install the stud assembly in the workpiece. Both the insert assembly and stud assembly are particularly adapted for use with workpieces made of relatively soft or lightweight materials.

Insert assembly for connecting fasteners to lightweight materials

A blind fastener for fastening panels, especially panels made of composite materials, comprises a fastener body received within aligned openings in the panels and a cylindrical stem passing through the fastener body. The stem has an enlarged stem head spaced from an inner end of the fastener body which projects inwardly beyond the inner surface of the inner panel. A deformable sleeve mounted on the stem between the stem head and the inner end of the fastener body is a two-piece sleeve comprising a forming sleeve and a containment sleeve. The forming sleeve is made of a relatively soft, deformable material, whereas the containment sleeve is made of a relatively hard, nondeformable material. When the stem moves outwardly through the fastener body during setting of the fastener, the forming sleeve deforms to a fully set condition in overlying contact with the inner surface of the inner panel, forming a large bearing area that does not damage the composite material of the panels. However, the containment sleeve remains substantially undeformed, allowing the fastener to apply and maintain high clamping loads.

Blind fastener with reinforced containment sleeve

Fastener with thread lock

A fastener having an internally threaded nut body, an externally threaded stem and a lock collar keyed to the nut body. The lock collar has a plurality of spring arms extending radially at an angle into the internally threaded bore of the nut body. During setting of the fastener, the stem is rotated in a tightening direction relative to the nut body. However, when the fastener is fully set, the spring arms will engage axial grooves in the stem to prevent relative rotation in a loosening direction between the nut body and the stem. This configuration forms a positive mechanical lock between the stem and the nut body and prevents the fastener from loosening and losing its clamping force, even when the fastener is subjected to high levels of stress and vibration.

Blind fastener with mechanical thread lock

A fastener and method for fastening panels is disclosed. The fastener comprises a bolt and a nut with a locking feature to prevent loosening of the fastener from vibration after it has been set. The locking feature comprises a frustoconical tip on the inserted end of the bolt that engages a retainer ring in the nut. When setting the fastener, the retainer ring deforms around the outer end of the tip and slides down the narrowing frustoconical surface of the tip until the fastener is fully set. Unthreading of the bolt from the nut is prevented since the retainer ring will resist deformation along the increasingly larger diameter portions of the frustoconical tip. In another aspect of the invention, the nut is provided with shear tabs which engage a wrenching tool. These tabs are designed to shear when the fastener is fully set to prevent further application of torque by the tool.

Fastener with locking retainer ring

A sleeve bolt for coupling together workpieces including a cylindrical sleeve having a cylindrical outer surface and an axial bore with a radially interior surface of polygonal configuration at one end and internal threads at the other end. An inner slide member with a polygonally shaped cross-sectional configuration positioned within the bore at the polygonally configured end for movement between a retracted orientation totally within the cylindrical sleeve and a protruding orientation partially withdrawn from the cylindrical sleeve. A coupling connects the inner slide member for sliding movement along the longitudinal axis of the sleeve between the retracted and protruding orientation and includes stop means connected to the sleeve for defining the limits of movement of the slide member between retracted and protruding orientations.

Sleeve bolt

A method of forming a lightweight threaded fastener element of bimaterial construction to high tolerance requirements, the element formed by the steps of shaping a metal shell to a preliminary configuration blank by extrusion, filling the extruded shell with a less dense material such as a curable epoxy-graphite material or an aluminum-lithium alloy, further shaping the filled blank by forging both the core material and shell to an intermediate configuration which is finished by warm rolling to form a strong lightweight fastener element configured with the metal shell thereof which may be engageable with a cooperating metal fastener assembly member.

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Alta Loma, CA, United States of America

Edgar L Stencel