Locking fastener
First Claim
Patent Images
1. In a prevailing-torque fastener combination:
- a first element having a helical thread form with leading and trailing flanks which lie at respective first angles to the thread axis and which, before threaded engagement with another element, intersect to define a crest of substantially constant diameter over the working length of said element;
a second element having a helical thread form with leading and trailing flanks which lie at respective second angles relative to the thread axis and which are truncated to define a root surface;
the first and second elements being conjugally threadable with one another;
at least a portion of the second element having a thread depth of lesser dimension than the thread depth of the first element thereby to cause firm radial engagement between the crest of the first element and the root surface when said elements are at least substantially fully threaded together;
the threads of said elements being configured to create longitudinal clearance between the flanks adjacent the engaging crest and truncated root sufficient to receive deformed material from said engaging crest when threaded together.
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Abstract
A vibration-resistant prevailing torque fastener combination comprising a conventional first element having a standard thread form with first flank angles and a modified second element having a thread form characterized by second steeper flank angles over the entire length thereof, and a truncated root caused by foreshortening of the flanks over a portion of the thread length to produce a helical flat which firmly engages and typically deforms the crest of the first element when threadedly engaged therewith. A difference in flank angles provides longitudinal clearance to receive the deformed material during the threaded engagement. Tapping tools are disclosed.
112 Citations
10 Claims
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1. In a prevailing-torque fastener combination:
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a first element having a helical thread form with leading and trailing flanks which lie at respective first angles to the thread axis and which, before threaded engagement with another element, intersect to define a crest of substantially constant diameter over the working length of said element; a second element having a helical thread form with leading and trailing flanks which lie at respective second angles relative to the thread axis and which are truncated to define a root surface; the first and second elements being conjugally threadable with one another; at least a portion of the second element having a thread depth of lesser dimension than the thread depth of the first element thereby to cause firm radial engagement between the crest of the first element and the root surface when said elements are at least substantially fully threaded together; the threads of said elements being configured to create longitudinal clearance between the flanks adjacent the engaging crest and truncated root sufficient to receive deformed material from said engaging crest when threaded together. - View Dependent Claims (2, 7)
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3. In a prevailing torque-fastener combination:
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a male element having a helical thread form with leading and trailing flanks which lie at respective first angles to the thread axis and which intersect to define a crest of substantially constant diameter over the working length of said element; a female element having a helical thread form with leading and trailing flanks which lie at respective second angles relative to the thread axis and which intersect to define a root; the first and second elements being conjugally threadable with one another; at least a portion of the female thread form root being of lesser diameter than the male crest to cause firm radial engagement therebetween when said elements are at least substantially fully threaded together; the second angles being greater than the corresponding first angles to create longitudinal clearance between the flanks adjacent the male crest and female root sufficient to receive deformed material from one of said elements when threaded together. - View Dependent Claims (4, 5, 6)
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8. For use in combination with a male threaded element having angled flanks and a constant thread diameter:
a female threaded element, the flanks of which lie at a greater angle relative to the thread axis than the corresponding flanks of the male element to provide longitudinal clearance between the flanks adjacent the crest of the male element and the root of the female element when the two elements are engaged, and a helical surface of truncation formed over at least a portion of the female root and which is of lesser diameter than the diameter of the male crown so as to produce firm radial engagement between said elements when substantially fully threadedly engaged. - View Dependent Claims (9, 10)
Specification