Torque Wrenches - my answer...

[Huw Powell]

>>> ... The 2079 tool does in fact act as a force multiplier
>>
>> How does it do that?
>>
> Good question.  By lengthening the lever arm.

But there is no lever arm lengthening going on.  If the business end of 
the torque wrench were fixed solid to the 2079, there would be.  But 
it's not, it is a pivot point, with its axis fixed relative to each 
tool, upon which the torque wrench is acting.

Picture the microcosm of the meeting point between the two tools, if you 
  will.  At that junction, there is a square hunk of metal, the driving 
nub thing of the torque wrench, that is imparting a twisting action to 
the 2079.  Each of the four faces of the "nub" are pushing in different 
directions, 90 degrees to each other, but all perpendicular to a radius 
drawn from the center of the nub.

In terms of its internal stresses, the 2079 is more like a chain drive 
with a pair of equal diameter gears at each end, moving the torque from 
its source to the fixed point at its other end.

Another mental picture that is useful, to realize that even though 
"torque" is described as a force on a lever in terms of its units, it is 
not always translatable back to that concept, is to think of a typical 
air driven impact wrench.  There is no lever arm, and certainly no huge 
operator effort, and yet the tool can deliver up to 600 ft lbs of torque 
at its little output nub.  A twisting force, or torque, not a weight 
applied to a lever.

So, does anyone up here in snowy (!) New England have a 2079 kicking 
around so I can play at some experiments and prove myself right or 
wrong? (at least to my satisfaction...)

-- 
Huw Powell

http://www.humanspeakers.com/audi

http://www.humanthoughts.org/