Gripper Springs

[slazbob]

I was wondering if anyone with some expertise with springs could shed some light on my thoughts about this?

i was thinking that a gripper spring with full-length arms mounted all the way down inside the handles (to the bottom) would make the gripper easier, than say an inch or two down?

my thinking...it would 

meaning: two springs of the same size; one with regular arms and the other with the long arms.

Edited September 1, 2019 by slazbob

[Daveyboy]

If the force is applied further away from the spring you'll get more leverage. My Spectrum 280N and 300N grippers have the same diameter spring, but the 300N spring is mounted deeper. It's rated at 144 pounds, whereas the 280N is 131 pounds. Silvis adjustable grippers work on the same principle.

[Fist of Fury]

17 hours ago, Daveyboy said:

If the force is applied further away from the spring you'll get more leverage. My Spectrum 280N and 300N grippers have the same diameter spring, but the 300N spring is mounted deeper. It's rated at 144 pounds, whereas the 280N is 131 pounds. Silvis adjustable grippers work on the same principle.

I don't think that's what he's asking.

He's asking about the spring itself, inside the handles. Good question by the way, I never even thought about it.

[Daveyboy]

OK, so it's two grippers that look identical from the outside but one has a spring with full length arms mounted really deep? I'm no spring expert, but I think they'd be the same. The force should only affect the visible section of the spring as the rest is inserted securely into the gripper handle. I'd put money on it, just not very much 🙄

It is a good question, I'd like to see what an expert said.

[Fist of Fury]

I actually think it would matter. But just like you I really don't know.

[Raymond]

It would depend on how the the spring is fitted into the handle, I've never seen how they're made or pulled one apart so I'm speculating mostly.

If the spring is a shrink fit then the only real difference would be the bend/flexural modulus of the aluminum handle. If the the bend modulus of the spring exceeds that of the handle (which it would only do with a MOFO spring) then a shorter spring insertion would produce a gripper that is slightly easier gripper to close. 

If it's a clearance fit and assembled with loctite or something similar you could get a few weird things happen on the first few closes but I think that would probably stop after a few reps and then become fairly predictable and settle in with similar characteristics as one with a longer spring.  In the end it's a basic moments equation where torque = force x distance and they are the same length of lever, so I don't think it would make a great deal of difference unless you had a really short insertion length or were using a spring that could overcome the bending modulus of the aluminum handle.

That being said without actually doing a side by side comparison, I couldn't say for sure.

Edited September 3, 2019 by Raymond

[wobbler]

With a rigid connection to the handle it would be 99.99% the same.

[slazbob]

Someone mentioned to me that the exposed part of the spring is all that matters. Like Davey Boy mentioned.

[Alawadhi]

@acorn is the man to ask.