When loads act heavily in only one specific direction, the thread profile most appropriate to employ is______________________?
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Answer: D. buttress thread
Explanation
The buttress thread profile features an almost perpendicular load-bearing flank on one side. This asymmetric design handles exceptionally high mechanical thrust loads acting in one dominant axial direction. The sloping trailing flank allows easy engagement while preventing radial separation under heavy unidirectional force. Thread geometry dictates how mechanical fasteners distribute applied shear and tensile forces. Symmetric threads distribute loads equally in both directions, whereas buttress threads optimize unidirectional strength. Manufacturing asymmetric thread profiles requires specialized tooling and precise lathe setup procedures.
Railway carriage drawbars and heavy-duty mechanical jacks utilize buttress threads for secure load handling. Press machinery applications require thread profiles capable of withstanding immense pressing force safely. Selecting appropriate thread profiles prevents thread stripping and joint failure under extreme service loads. ISO metric threads are general-purpose fasteners designed for bidirectional loading rather than heavy thrust. Acme threads handle bidirectional motion in feed mechanisms, lacking the asymmetric thrust advantage of buttress threads. Square threads offer high efficiency but lack the robust flank angle required for extreme unidirectional loads.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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