Jackbolts for multi jackbolt tensioners
First Claim
1. A method for establishing a clamping force between bolted parts, said method including the steps of:
- selecting an elongated fastener having a stress generator and a connector at opposite ends of a shank portion;
selecting jackbolts having threaded shanks between torque receiving ends and opposite compressively stressable ends, said compressively stressable ends each having a protruding central area along a longitudinal axis of each jackbolt for reducing bearing friction and preventing fretting under compressive stress, said jackbolts having a preselected elastic characteristics to allow elastic flattening of the protruding central area at said compressively stressable ends; and
torquing said jackbolts in threaded openings spaced about an outer peripheral part of said stress generator sufficient to produce elastic flattening of said compressively stressable ends and stress said shank portion for establishing a clamping force between such bolted parts.
2 Assignments
0 Petitions
Accused Products
Abstract
Jackbolts for multi jackbolt tensioner embody a thread construction which taper from a maximum diameter adjacent to torque receiving end of the jackbolt when threadedly engaged with a threaded opening in the outer peripheral part of a jackbolt body. The threads of the jackbolt have a different thread pitch than the threads in the jackbolt body and the tooth flank of the jackbolt threads for an angle with the tooth flanks of the thread in the jackbolt body. By this thread construction, there is formed a helical volume of ever increasing size along the jackbolts commencing at a metal to metal relation at the torque receiving end. Stressing of the jackbolt closes the helical volume bringing the threads to a metal to metal load transfer relation. The end of the jackbolts has a protruding central end portion that elastically flattens under stress to reduce torque requirements.
35 Citations
12 Claims
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1. A method for establishing a clamping force between bolted parts, said method including the steps of:
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selecting an elongated fastener having a stress generator and a connector at opposite ends of a shank portion; selecting jackbolts having threaded shanks between torque receiving ends and opposite compressively stressable ends, said compressively stressable ends each having a protruding central area along a longitudinal axis of each jackbolt for reducing bearing friction and preventing fretting under compressive stress, said jackbolts having a preselected elastic characteristics to allow elastic flattening of the protruding central area at said compressively stressable ends; and torquing said jackbolts in threaded openings spaced about an outer peripheral part of said stress generator sufficient to produce elastic flattening of said compressively stressable ends and stress said shank portion for establishing a clamping force between such bolted parts. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification
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- Resources
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Current AssigneeNord-Lock Switzerland GmbH (Investment AB Latour)
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Original AssigneeSteinbock Machinery Corp.
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InventorsSteinbock, Rolf H.
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Primary Examiner(s)Bryant, David P.
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Assistant Examiner(s)Cozart, Jermie E.
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Application NumberUS09/290,795Time in Patent Office511 DaysField of Search29/452, 411/432, 411/14.5, 411/917, 411/916, 411/393, 403/362, 81/57.38US Class Current29/452CPC Class CodesB23P 19/067 Bolt tensioners for hand to...B25B 29/02 Bolt tensionersF16B 31/04 for maintaining a tensile loadF16B 33/02 Shape of thread; Special th...Y10S 411/916 Bolt having tension featureY10S 411/917 Nut having tension featureY10T 29/49874 Prestressing rod, filament ...
