Problem understanding the forces applied to a threaded fastner

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Discussion Overview

The discussion revolves around understanding the forces applied to a threaded fastener, specifically addressing confusion regarding the forces denoted as Pr and PL in relation to a diagram that some participants believe is misidentified as pertaining to a threaded fastener rather than a power screw. The scope includes conceptual clarification and technical explanation.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant expresses confusion about the forces Pr and PL, stating that they only recognize the applied force F.
  • Another participant suggests that the confusion arises from the diagram being for a 'Power Screw' rather than a threaded fastener, indicating that the forces are related to the load being raised or lowered.
  • It is mentioned that Pr and PL correspond to the torque required to turn the screw and lift or lower the load.
  • Several participants share references and resources related to threads, indicating a desire to provide additional context and information.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the identification of the diagram, with some asserting it is a power screw while others seem to accept the clarification regarding the forces involved. The discussion remains somewhat unresolved regarding the initial confusion about the forces.

Contextual Notes

The discussion highlights potential limitations in understanding due to the misidentification of the diagram and the specific definitions of the forces involved. There is an indication that further clarification may be needed regarding the relationship between torque and the forces on the fastener.

Amaelle
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TL;DR
Threaded fastner
Greeting I have a problem understanding the forces applied to a threaded fastner
1636383873013.png

I really don't understand from where they got Pr or PL because for me the only applied force is F
thank you!
 
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The confusion is probably because the diagram isn't for a threaded fastener - it's for a 'Power Screw.' The screw is raising (or lowering) a load - that's where the 'mystery' forces come from.
 
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PR and PL correspond to the torque required to turn the screw (and lift or lower the load).
 
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Dullard said:
The confusion is probably because the diagram isn't for a threaded fastener - it's for a 'Power Screw.' The screw is raising (or lowering) a load - that's where the 'mystery' forces come from.
thank you very much
 
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onatirec said:
PR and PL correspond to the torque required to turn the screw (and lift or lower the load).
thank you I got it now!
 
@Amaelle
I just thought I would provide a good reference on threads. See attached .pdf file
 

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dlgoff said:
@Amaelle
I just thought I would provide a good reference on threads. See attached .pdf file
thanks a million!
 
Amaelle said:
thanks a million!
You're welcome. Hope it will be useful in your future.
 
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