摘要:
A collar threads onto a shear pin. When the collar engages a surface of a workpiece, resistance to further threading increases. When sufficient resistance to threading occurs, a setting driver upsets lobes of the collar and forces these lobes radially inward toward the axis of the collar. Material of the collar inside the lobes responds to deformation of the lobes and flows radially inward against the shear pin to lock the collar, shear pin and workpiece together. The driver then rotates freely and a joint has been made with a predetermined clamp-up load and its component parts locked together.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A mechanically locking fastener has external threads for installation in the threaded bore of a workpiece. A lock ring has internal radial serrations locked in serrations of the fastener proper, and external radial teeth of a form for gripping the wall of the workpiece bore when turning moments tend to loosen the fastener and to pass over the bore wall upon rotation in the opposite direction. The lock ring has a slip plane to permit contraction of the ring to a diameter no greater than the major diameter of the fastener and expansion of the ring when the fastener undergoes moments tending to loosen it. The fastener proper may be a stud or an insert. An external chamfer of the ring bears against a cooperating internal surface of the workpiece to positively determine the axial location of the insert with respect to the workpiece.
摘要:
A blind fastener system comprising a ductile sleeve having an expansion portion of small inner diameter in a thin workpiece and having a bulbing portion of larger inner diameter extending on the blind side of the workpiece, and a threaded expander member having an expander portion for expanding the sleeve expansion portion and a head portion for bulbously deforming the sleeve bulbing portion, both actions occurring on axially pulling the expander member. The expander portion has a tapered, radiused leading end followed by a configured (splined, knurled, etc.) portion for the remainder of the active length. The protrusions of the configured portion leave a void volume between them and between the minor and major diameters of the protrusions, and the volume of the sleeve expansion portion between the small inner diameter and the projection of the large inner diameter is approximately 0.5 to 0.8 of the void volume of the configured portion. The protrusions have blunt outer surfaces. The expander member may be a nut, in which case the minor diameter of the protrusion is at least 1.23 times the major diameter of the internal threads of the expander member, which threads are inwardly of at least a portion of said protrusions. The length of the bulbing portion is approximately one-half the outer diameter thereof, while the large inner diameter is approximately nine-tenths of the outer diameter of the sleeve bulbing portion. The axial length of the sleeve expansion portion is at least equal to the thickness of the workpiece, and the expansion section of the expander member is at least equal to the axial length of the expansion portion of the sleeve.The expander member may have internal threads, to serve as a nut, or may have a stem with external threads, to serve as a bolt or stud. The stud may receive an electrical connector, the fastener system being of suitable electrically conductive materials.
摘要:
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.
摘要:
A driver has a deltoid wrenching and deforming socket in the form of an equilateral triangle with rounded corners. Flats of the socket between the apexes of the triangle bear on lobes of a collar to thread the collar onto a pin in the making of a joint. At a predetermined clamp-up load on the joint, the flats of the deltoid socket crush the lobes plastically and force material of the collar radially inward of the lobes into locking engagement with the pin. Thereafter the socket can rotate freely on the collar. A pilot section of the deltoid socket cooperates with a corresponding section of the collar to keep the driver from canting off axis. Reliefs with cylindrical surfaces in the sides of extensions of the flats define piloting surfaces of the pilot section.
摘要:
A blind fastener has a nut with a threaded bore, a core bolt having external threads for receipt by the nut, and a sleeve for expansion by the head of the core bolt and a shoulder of the nut to form a blind side folded bulb against the backside sheet of a joint. A thin-walled, tapered section of the sleeve fits over a relieved section of the nut and bears against the shoulder of the nut. The taper is such that the thin wall increases in thickness away from the shoulder. An axially adjacent thick-walled section of the sleeve bears on the core bolt head and resists sleeve tuck-out over the core bolt head, concentrically aligns the sleeve on the core bolt, and assures that the thin-walled section of the sleeve is the section that bulbs. During setting, the sleeve expands by compression exerted on it by the core bolt head and the shoulder. The thin wall section folds against the backside sheet with an ever-increasing area as tightening continues. The fold always develops against the backside sheet because the portion of the sleeve free of the sheet is weakest in compression there. Axial clamp-up force is spread over a large area of the sheet but unit loading is low.