Hi,


I'm an undergraduate industrial design student.
I'm working on an (I think) incredibly interesting project.


I want to design a flexible/twistable/bendable torque wrench.
The concept is to make a the body completely flexible (like a snake) to get into difficult spaces. I have been working tirelessly on this for the past month, but have yet to come up with a mechanism that works.


The problem is quite obvious. The wrench needs a sort of locking mechanism where the body and head connects. The mechanism has to lock the body in position so that the user can use it to turn the object.


Any suggestions would be greatly appreciated.


Thanks

 

This is not what I'd do in a real-life setting, but it's a school project, so go crazy

How about filling the connecting channel between the handle and head with coffee grounds. Then, when you're ready to turn the handle, activate a pump to suck all the air out. That will make the connection rigid in whatever position it's in. When you're done, allow air back in.
There are a few companies that make universal robot grippers with this kind of scheme.

 

A bunch of short cylindrical segments.
They have a hole down the axis.
One end has a spherical end.
The other has a concave spherical recess.
string a bunch of these nesting segments onto a steel cable.
Attach cable to the head and handle.
Handle end needs an over center cam action lever to pull the cable REALLY tight.
That will lock the segments in place with friction.
Modifying the shape of the sphere to have small ribs that run longitudinally around the spheres would allow the joint to articulate but transmit torque.

 

You also might want to explore universal joints. They allow you to rotate around either minor axis, but transmit torque around the major axis of your joint.