Machine Analysis -- gripping pliers

  • Engineering
  • Thread starter mingyz0403
  • Start date
  • #1

Homework Statement:

the pliers shown are used to grip a 0.3-in.-diameter rod. knowing that two 60-lb forces are applied to the handles, determine (a) the magnitude of the forces exerted on the rod, (b) the force exerted by the pin at a on portion ab of the pliers.

Relevant Equations:

3 reaction equation
I know that moment is distance vector x force vector x the degree between them. I understand it uses the moment about A to solve for the unknown force R. I don’t understand why it use Rx1.2m and why the perpendicular distance between A and R is 1.2m.

could anyone please explain why?
Many thanks for your time answering
 

Attachments

Answers and Replies

  • #2
722
423
The angle is irrelevant in this case; you would have the same forces for 90° misalignment among the levers.
The reason is that moment around a fulcrum is the same for any angle contained in the plane of the force(s).

Imagine that you have two disks that share a central pivot and tangetial opposite forces creating a relative circular movement.
At any point that have same radius you can reproduce those forces.

The rivets or bolts that connect a brake disk and a wheel all are expossed to similar shear load when the caliper clamps the rotating disk.

se-Pliers-f33f8de7-2063-4a83-ae86-c05e7edf384d_600.jpg
 

Related Threads on Machine Analysis -- gripping pliers

  • Last Post
Replies
4
Views
2K
Replies
5
Views
5K
Replies
37
Views
1K
  • Last Post
Replies
6
Views
961
  • Last Post
Replies
3
Views
658
Replies
5
Views
1K
  • Last Post
Replies
16
Views
5K
  • Last Post
Replies
0
Views
1K
  • Last Post
Replies
1
Views
654
  • Last Post
Replies
5
Views
471
Top