Reverse compound leverage for increased plier head splay, reduced handle splay

[Raukodur]

One issue with multitools is how wide the plier head opens and how at maximum opening width, the handles are splayed out so far, you'd have to use two hands.

With SOGs compound leverage, this problem is magnified, for the benefit of ?doubling the force exerted

What if there was a MT with reverse compound leverage - to maximise the splay of the plier heads while still being able to use the tool one handed due to minimal splay of the handles? You would be sacrificing the amount of force exerted, but wouldn't this be offset by the increased amount of force you could exert due to the handles being closer together and so the better grip you'd have?

[Syncop8r]

I have wondered about this myself. I wonder how much force you would sacrifice... 

[RF52]

Very interesting

Sent fra min FRD-L09 via Tapatalk

[Raukodur]

Anyone with any engineering know-how got any thoughts about the feasibility and effect on function of something like this?

[Raukodur]

Maybe I should have posted this is the general forum...

[Syncop8r]

Upon further thought I don't think there is any real advantage (for the sacrifice of the gearing required), so long as manufacturers design the handles to not splay so much when the pliers are closed (which many don't).

[gerleatherberman]

Not sure that would have made a difference. 

I think of it in two ways.

1) If I need pliers that open wider than any other MT, then I just need to go get a set of channellocks. Carrying an MT that is only good for applying far less of the hand force won't be very practical compared to an MT that applies as much force as the design is capable of exerting. Most MT related plier tasks need the most force applied transfered to the pliers as possible (or better, like compound leverage).
2) If I have something large I need wide-opening pliers for, then getting significantly less force at the jaws, because of reverse leverage, will defeat the purpose of being able to grip it. I'm likely going to need more force than that on something large.

That's my $0.02 anyway. I may be seeing the idea incorrectly. 

[Syncop8r]

I don't think this is about having pliers that open wider than normal multitools, rather not having the handles splayed so wide when they are at max width.

The OP is suggesting that perhaps the force won't be significantly less because your hand can close around the handles more easily.

[Raukodur]

I don't think this is about having pliers that open wider than normal multitools, rather not having the handles splayed so wide when they are at max width.

The OP is suggesting that perhaps the force won't be significantly less because your hand can close around the handles more easily.

You are correct.

One way some MTs have tackled this is by the shape of the handles curving inwards when in plier mode, e.g. Spirit.

[gerleatherberman]

Minimal splay you say? Get a Gerber MP400/600. 

[Vidar]

If you are willing to sacrifice pliers grip strength for less splay I think the easiest solution would be shorter handles.

As for the hand grip strength it is true that strength varies with grip width. The curve of force as a function of splay has a fairly flat top, so there is a range of splay where maximum force is fairly stable. For pliers an splay of 60-90mm should be around the sweet spot. This will of course vary with the size of the hand though. From there the drop off isn't very dramatic so the hand can grip fairly well over a wide range.

There are other factors too though that are important for effective grip strength and its actual use. Handle shape is one which is well known from sharp edged multi-tool handles. Another one that is often overlooked is twisted wrists.

Twisting the wrist, as needed for straight head pliers, is usually just mentioned with regards to repetitive strain injury as it puts the wrist in a far from neutral position. Ergonomic pliers with a bent head helps reduce that problem, but the max grip force with such pliers is also higher. (Just try gripping something with your wrist neutral as compared to a position pointing down with your pointy finger and then gripping).

[smiller43147]

If I need pliers that open wider than any other MT, then I just need to go get a set of channellocks.

Now there is the solution to both the issues mentioned at the beginning: how wide the pliers open, and how far apart the handles spread.
With an adjustable set of pliers you can greatly increase how wide they open, while keeping the jaws parallel AND minimize the handle spread.
Most pliers of this design have 5 or 6 different jaw widths, too much to add to an MT.  Just adding a second jaw width (like a pair of slip joints) would greatly address this issue.

[gerleatherberman]

You may already know about these, but I'll post them for anyone who isn't familiar.
A couple of MTs have attempted to incorporate slip joint plier heads into an MT. The Schrade ST5E and Sheffield 12020.
The execution could have been better, but these do work. I wish another company would have a go with the slip joint pliers.
(One in the middle is Schrade ST5E).



Sheffield 12020.



Edit: typo.

[Raukodur]

Why don't more MT manufacturers use slip joint plier heads?

[gerleatherberman]

Why don't more MT manufacturers use slip joint plier heads?

I sure wish they would. The Schrade ST5E and Sheffield 12020 were fairly good attempts..IMO The Schrade was the expensive one and the Sheffield was the cheaper tool. Both have their merits and benefits, but they really need improving upon. I think LM, Victorinox, SOG, Bear & Sons, and a myriad of other reputable MT companies could make a proper slip-joint multi-tool if they made it a goal.

And, I must apologize to you, Raukodur.
My original reply was made with the presumption that you knew about the existing slip-joint multi tools. I assumed you were eluding to a multi-tool that was geared in reverse to the compound leverage SOGs(something that doesn't exist). A tool that would open wider in ratio to the handle movement. I apologize for the presumption about that. I hope we are on the same page now.

[Syncop8r]

I assumed you were eluding to a multi-tool that was geared in reverse to the compound leverage SOGs(something that doesn't exist). A tool that would open wider in ratio to the handle movement. I apologize for the presumption about that. I hope we are on the same page now.

I thought that was exactly what we were talking about.    But not having the jaws open wider, just the handles opening less.

[gerleatherberman]

I assumed you were eluding to a multi-tool that was geared in reverse to the compound leverage SOGs(something that doesn't exist). A tool that would open wider in ratio to the handle movement. I apologize for the presumption about that. I hope we are on the same page now.

I thought that was exactly what we were talking about.    But not having the jaws open wider, just the handles opening less.

My first post:

Not sure that would have made a difference. 

I think of it in two ways.

1) If I need pliers that open wider than any other MT, then I just need to go get a set of channellocks. Carrying an MT that is only good for applying far less of the hand force won't be very practical compared to an MT that applies as much force as the design is capable of exerting. Most MT related plier tasks need the most force applied transfered to the pliers as possible (or better, like compound leverage).
2) If I have something large I need wide-opening pliers for, then getting significantly less force at the jaws, because of reverse leverage, will defeat the purpose of being able to grip it. I'm likely going to need more force than that on something large.

That's my $0.02 anyway. I may be seeing the idea incorrectly. 

Your reply:

I don't think this is about having pliers that open wider than normal multitools, rather not having the handles splayed so wide when they are at max width.

The OP is suggesting that perhaps the force won't be significantly less because your hand can close around the handles more easily.

OP''s response:

I don't think this is about having pliers that open wider than normal multitools, rather not having the handles splayed so wide when they are at max width.

The OP is suggesting that perhaps the force won't be significantly less because your hand can close around the handles more easily.

You are correct.

One way some MTs have tackled this is by the shape of the handles curving inwards when in plier mode, e.g. Spirit.

Does it make sense that I was approaching this from a different angle than you and OP were? In my mind, I was thinking about the size of object to be gripped and you/OP were talking about minimizing handle splay.
Even though, both of us were saying something similar, just from different ends of the MTs. The quick correction/OP's agreement of my post made me wonder what the heck was going on. I am apologizing for instilling confusion, although it was inadvertent.

[Vidar]

Even though, both of us were saying something similar, just from different ends of the MTs. The quick correction/OP's agreement of my post made me wonder what the heck was going on. I am apologizing for instilling confusion, although it was inadvertent.

I might be confused or confusing too? I thought this was about shifting the relation between the pliers jaw opening and pliers handle splay towards more jaw opening and less splay.

Maybe I'm looking at the wrong problem but the easiest way to do the above is either longer pliers jaws (ie more spread jaw opening further out) and or shorter pliers handles (less splay). Longer pliers jaws will maintain the previous maximum leverage at the root and add some wider gripping opportunity at the cost of lower leverage at the tips. Shorter pliers handles will reduce leverage all around.

That said I've seen multi-tools with reverse compound action (ie the angle of the pliers jaws closes faster than the handle angle). Some of those flip out pliers head multi-tools where springs return half the pliers head to open if I remember correctly.

[smiller43147]

You may already know about these

I didn't.  Thanks for the post.

[gerleatherberman]

You may already know about these

I didn't.  Thanks for the post.

Of the two. The Sheffield is slightly better on the pliers side. The tools are good, but the extraction is stiff and antithetical to smooth. A little needle-file work would get it up to snuff though. Keep in mind. The ST5E and 12020 are bulky and unwieldy. The 12020 is a bit more streamlined, but at 10.5oz, it is beastly.

Even though, both of us were saying something similar, just from different ends of the MTs. The quick correction/OP's agreement of my post made me wonder what the heck was going on. I am apologizing for instilling confusion, although it was inadvertent.

I might be confused or confusing too? I thought this was about shifting the relation between the pliers jaw opening and pliers handle splay towards more jaw opening and less splay.

Maybe I'm looking at the wrong problem but the easiest way to do the above is either longer pliers jaws (ie more spread jaw opening further out) and or shorter pliers handles (less splay). Longer pliers jaws will maintain the previous maximum leverage at the root and add some wider gripping opportunity at the cost of lower leverage at the tips. Shorter pliers handles will reduce leverage all around.

That said I've seen multi-tools with reverse compound action (ie the angle of the pliers jaws closes faster than the handle angle). Some of those flip out pliers head multi-tools where springs return half the pliers head to open if I remember correctly.

Well said, sir! I think we're on the same page now.

[Vidar]

Well said, sir! I think we're on the same page now.

It happens that I stumble upon expressing something that makes sense to someone Even blind hens are right two times per day!

Interesting collection of slip joint pliers by the way. From the more elaborate head construction I assume these were on the expensive side compared to other similar styled normal head multi-tools?

[gerleatherberman]

Thank you, Vidar!

The Schrade (mine is rebranded a Craftsman) was pretty expensive when new. About $79.99 in 1999 and the Schrade version, released in 2003 was still $79.99.
They were about the same price as the needle nose Tough Tool, which was surprising, when I did the research.
I have no idea on the Sheffield, but those were generally half of their competition's price back in "the day".
I paid $90 for my ST5E(Craftsman rebrand barely used), but I've seen them unused for $200 at times.
I paid $20 for the unused Sheffield on Ebay last week.
As far as I know, those two are the only production slip-joint MTs made. Maybe I'm wrong?

[Vidar]

As far as I know, those two are the only production slip-joint MTs made. Maybe I'm wrong?

I had only heard of them until I saw your pictures, so for me you are the authoritative expert on the subject! 

I guess one can make the argument that the SAK pliers are slip joints?

[gerleatherberman]

As far as I know, those two are the only production slip-joint MTs made. Maybe I'm wrong?

I had only heard of them until I saw your pictures, so for me you are the authoritative expert on the subject! 

I guess one can make the argument that the SAK pliers are slip joints?

Hmmm. I guess you could make that point about SAK "pliers", but I don't know if slip-joint tweezers count.

Tweezers compared to the ST5E and 12020 slip-joint pliers.

[Vidar]

Hmmm. I guess you could make that point about SAK "pliers", but I don't know if slip-joint tweezers count.

I think of them as "pinchers".

[gregozedobe]

Thank you, Vidar!

The Schrade (mine is rebranded a Craftsman) was pretty expensive when new. About $79.99 in 1999 and the Schrade version, released in 2003 was still $79.99.
They were about the same price as the needle nose Tough Tool, which was surprising, when I did the research.
I have no idea on the Sheffield, but those were generally half of their competition's price back in "the day".
I paid $90 for my ST5E(Craftsman rebrand barely used), but I've seen them unused for $200 at times.
I paid $20 for the unused Sheffield on Ebay last week.
As far as I know, those two are the only production slip-joint MTs made. Maybe I'm wrong?

The only others I can think of made in recent decades are a couple of French MTs with slip joint pliers:  Wichard and Le Depanneur.  These have non-folding pliers and are significantly smaller and less robust than the Schrade Craftsman and Sheffield slip-joint pliers.  But I am reluctant to say that there are no others, inventors can be pretty imaginative and inventive, especially in the "old-iron" days.

[gerleatherberman]

Thanks, gregozedobe!

I hope there are more, but I've read hundreds of things about the ST5E and 12020, never seeing mention of any other folding slip-joint MT.
Most sites say the ST5E was the only one, but there is the Sheffield, so maybe there are others "under the radar".

[Raukodur]

To clarify any confusion, my point was about having a system on a MT to minimise handle splay, especially when gripping 'larger' things.

The suggestion I had was reverse compound leverage, but the downside of this is reduced pressure exerted by the pliers. I was wondering though whether this would be countered by the better grip you could have on the less-splayed handles, allowing you to squeeze more.

However, the slip-joint plier heads presented here would potentially give you the benefit of reduced handle splay without reduced plier pressure.

Given the way the LM crunch is designed, couldn't it also be possible for the plier head to be at an angle?

I think MTO need to make their own multitool...

[Vidar]

The suggestion I had was reverse compound leverage, but the downside of this is reduced pressure exerted by the pliers. I was wondering though whether this would be countered by the better grip you could have on the less-splayed handles, allowing you to squeeze more.

If the pliers start off from a somewhat normal splay, and the reduced leverage is enough to be of some effect, then I'll go ahead and guess it will not compensate. If the needed splay is such that you can hardly reach across with your fingers then likely yes.

My point above was that the issue at its core is the leverage ratio and range of movement. Compound leverage is just one way to manipulate that, and varying the length of the handles will achieve the same. A Leatherman with say twice as long handles would have the same leverage and splay to jaw opening ratio as a SOG with a 2:1 compound leverage. Equally would half as long handles do the same as a 1:2 reduced compound leverage - but in a simpler and more compact way I think? (It is possible to make a plier with adjustable leverage and thus splay to opening ratio, but I'm not sure who would be interested in that? One could even argue that you have that in normal pliers as you can manipulate where the jaw grips and where you hold the handles?).

However, the slip-joint plier heads presented here would potentially give you the benefit of reduced handle splay without reduced plier pressure.

The trade off is the lacking ability to close fully from all positions. Depending on the application that might be important?

Given the way the LM crunch is designed, couldn't it also be possible for the plier head to be at an angle?

Some multi-tools already have them at an angle (SOG Switchplier for instance), while other designs like say most Leatherman styles could easily do that if they wanted to.