FORCES

[johnboy]

Please can anyone help me with a little fundamental.
If you imagine a clamp which has two upright legs pivoted at the bottom and connected firmly to a base and the tops are tied together with a pneumatic cylinder with pivoting clevis's each end.
If half way along the vertical legs is attached some jaws which can pivot. These are the clamp jaws.
If the cylinder exerts 100 newtons say of force then what force does each jaw exert.
If one leg was made fixed and the cylinder end fixed firmly, only one jaw would move and if 100 nwetons was exerted once again what force would the jaw exert.
IS IT HALF WHAT THE TWIN JAW SYSTEM EXERTED.??

 

[svanels]

Send a sketch !

Regards Steven van Els
SAvanEls@cq-link.sr

 

[mark20]

Johnboy,
The answer is a simple bending moment equasion.

Imagine one of the legs is fixed work out the total force and divide by 2.

IE. 100N at ????m (distance from pivot - Take the pivot as being where your clamps jaws are.
basically Force x Distance.

Hope this helps.
Mark.

 

[Gaz]

One fixed leg and one pivoted leg. If your jaws were halfway your force on the movable jaw would be double the rams force. eg.100N*X divided by X/2 = 100N*2 = 200N (Force times the distance to the pivot divided by the distance from the pivot to the jaws.)

Both legs pivoted.
(This is johnboy's problem.) This is like a scissor problem but with the force measured between the handles not the blades!.

My answer.
I think, if both legs were pivoted, the TOTAL force the jaws exerted on something would be the same (200N). Each jaw would then exert half the force on an object.

Would any engineer out there like to clarify this?.