A fastener (2) for securing a workpiece comprising a plurality of workpiece members, said fastener comprising a shank (4) and a radially enlarged head (6) wherein the fastener further comprises axial voids (40) and splines (18), such that when the fastener is installed into a workpiece by a mandrel,
A fastener (2) for securing a workpiece comprising a plurality of workpiece members, said fastener comprising a shank (4) and a radially enlarged head (6) wherein the fastener further comprises axial voids (40) and splines (18), such that when the fastener is installed into a workpiece by a mandrel, breakstem or pin, the shank of the fastener is expanded such that the crests of the splines are caused to mechanically engage with the internal walls of the fastener apertures.
대표청구항▼
1. A fastener, for securing a workpiece comprising a plurality of workpiece members, said fastener comprising a shank with a head end and a tail end remote from the head end, and a radially enlarged head at the head end of the shank, and a fastener bore extending throughout the fastener,wherein an e
1. A fastener, for securing a workpiece comprising a plurality of workpiece members, said fastener comprising a shank with a head end and a tail end remote from the head end, and a radially enlarged head at the head end of the shank, and a fastener bore extending throughout the fastener,wherein an external wall of the shank comprises a voided section comprising a plurality of voids separated by a plurality of splines each of which culminates in a crest, the voids and splines being elongated in an axial direction with respect to a longitudinal axis of the fastener bore; wherein the splines are of an approximate trapezoidal cross-section, wherein the voids have a cross-sectional area which is constant along the length of the voided section of the fastener shank, andwherein the shank includes an unvoided solid tail ring between the voided section and the tail end of the shank, the unvoided solid tail ring having an external diameter approximately equal to the external diameter of the shank in the voided section. 2. A fastener as claimed in claim 1 wherein the axial voids are equidistant from one another. 3. A fastener as claimed in claim 1 wherein the axial voids extend from immediately underneath the fastener head. 4. A fastener as claimed in claim 1 wherein the fastener head comprises a countersink provided in a top surface of the head remote from the fastener shank, the countersink having an average diameter which is greater than the diameter of the fastener bore. 5. A fastener as claimed in claim 4 wherein, the countersink comprises a flat annular tapered wall. 6. A fastener as claimed in claim 4 wherein the countersink comprises a curved tapered annular wall. 7. A fastener as claimed in claim 4 wherein the countersink comprises a flat annular wall which is parallel to the longitudinal axis of the fastener bore. 8. A fastener as claimed in claim 4 wherein a tapered neck portion is provided between the countersink and the fastener bore. 9. A fastener as claimed in claim 1 further comprising a tapered point at the tail end of the fastener shank. 10. A fastener as claimed in claim 9 further comprising an end section at the tail end of the fastener beyond the tapered point, the end section having a straight annular wall which is parallel to a longitudinal axis of the fastener. 11. A fastener as claimed in claim 10, wherein the diameter of the end section is less than the diameter of a countersink provided in a top surface of the head remote from the fastener shank, the countersink having an average diameter which is greater than the diameter of the fastener bore. 12. A fastener as claimed in claim 1 further comprising a solid tail ring at the tail end of the fastener shank, between the voided section and the tapered point. 13. A method of installing a fastener according to claim 1, thereby to secure a workpiece comprising a first a pertured workpiece member and a second apertured workpiece member, the method comprising the steps of; a) placing a mandrel having a radially enlarged head through a fastener bore such that the radially enlarged head of the mandrel is adjacent a tail end of a fastener shank;b) inserting the fastener and mandrel into the apertures in the first and second workpiece members such that the fastener head contacts the first workpiece member;c) supporting the fastener at a head end whilst drawing the mandrel entirely through the fastener bore, thereby expanding the fastener shank into the apertures of the workpiece members, and causing the crests of the splines to be deformed against the apertures, and causing the tail end of the fastener shank to radially enlarge adjacent to the second workpiece member. 14. A method as claimed in claim 13 wherein step c) is undertaken by a tool comprising a conical concave end face which bears on an upper surface of the fastener head. 15. A method of installing a fastener according to claim 1, thereby to secure a workpiece comprising a first apertured workpiece member and a second apertured workpiece member, the method comprising the steps of; a) inserting a stem comprising a radially enlarged head, a breakneck point, and a plugging portion, into the fastener through the fastener bore such that the radially enlarged head of the stem is adjacent the tail end of the fastener shank;b) inserting the fastener and the stem into the apertures in the first and second workpiece members such that the fastener head contacts the first workpiece member;c) supporting the fastener at the head end whilst pulling the stem with respect to the fastener head, thereby causing the plugging portion to radially expand the fastener shank into the apertures of the workpiece members and deform the crests of the splines against the apertures, and also thereby causing the radially enlarged head of the stem to contract, and then compress, the tail end of the fastener shank, thereby causing the tail end of the fastener shank to radially enlarge adjacent to the second workpiece member; wherein the stem is pulled with respect to the fastener head through the fastener bore until the stem fractures at the breakneck point. 16. A method of installing a fastener according to claim 15, wherein the stem further comprises a parallel portion between the breakneck point and the plugging portion, and wherein, during step c), a locking skirt is created by the parallel portion, thereby providing a mechanical lock of the installed stein in the fastener shank. 17. A method of installing a fastener according to claim 1, thereby to secure a workpiece comprising a first apertured workpiece member and a second apertured workpiece member, the method comprising the steps of; a) inserting the fastener into the apertures in the first and second workpiece members such that the fastener head contacts the first workpiece member;b) inserting a breakstem comprising a plugging portion with a hollow core, an elongate shank, and a breakneck point between the plugging portion and the elongate shank, into the bore of the fastener, such that the plugging portion of the breakstem contacts the tail end of the fastener shank;c) pulling the elongate shank of the breakstem pulled relative to the fastener, thereby causing the breakstem plugging portion to enter the fastener shank, causing the fastener shank to expand into the workpiece apertures, and causing the crests of the splines to be deformed against the apertures, and simultaneously causing the plugging portion to collapse inwardly; wherein the elongate shank is pulled relative to the fastener until the breakstem fails at the breakneck point. 18. A method of installing a fastener according to claim 1, thereby to secure workpiece comprising a first apertured workpiece member and a second apertured workpiece member, the method comprising the steps of; a) inserting the fastener into the apertures in the first and second workpiece members such that the fastener head contacts the first workpiece member;b) driving a solid pin, having a maximum diameter larger than that of the fastener bore, into the bore of the fastener via the head thereby to radially enlarge the fastener shank into mechanical engagement with the workpiece apertures, and causing the crests of the splines to be deformed against the apertures. 19. A method of installing a fastener according to claim 18 further comprising a subsequent step of bearing on the fastener head by a support sleeve, and removing the pin From the fastener bore. 20. Fastening apparatus, for securing a workpiece comprising a plurality of workpiece members, said apparatus comprising a fastener and a mandrel; said fastener comprising a shank with a head end and a tail end remote from the head end, and a radially enlarged head at the head end of the shank, and a bore extending throughout the fastener;wherein an external wan of the shank comprises a voided section comprising a plurality of voids separated by a plurality of splines each of which culminates in a crest, the voids and splines being elongated in an axial direction with respect to a longitudinal axis of the fastener bore; wherein the splines are of an approximate trapezoidal cross-section;wherein the voids have a cross-sectional area which is constant along the length of the voided section of the fastener shank; andwherein the shank includes an unvoided solid tail ring between the voided section and the tail end of the shank, the unvoided solid tail ring having an external diameter approximately equal to the external diameter of the shank in the voided section. 21. Fastening apparatus as claimed in claim 20 wherein said mandrel comprises a radially enlarged head of a maximum diameter which is greater than a diameter of the fastener bore, and less than a maximum external diameter of the fastener shank.
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이 특허에 인용된 특허 (10)
Williamson Herman L. (Seal Beach CA) Schuster Michael M. (Santa Monica CA), Blind fastener.
Aurtoi Jean-Marc (Flourens FRX) Bornes Philippe (Flourens FRX), Process for distribution of pieces such as rivets, and apparatus for carrying out the process.
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