Look up the Snap 'n Cut. Home Page
Okay...been a while since I was last here (Welcome back, jgramlich, there have been 146,333 posts and 20,236 threads since your last visit at 11:24 PM, 12-10-2010). I need some help reinventing the wheel.
A customer has a Farley plasma table. Slats too far apart for small parts, table not deep enough, parts stick up into the air, etc. For all intents and purposes, the torch is mounted on the gantry frame. There is no breakaway...in fact, the torch holder is encased in a steel frame of its own (on a 45 deg pivot for bevels). Effectively, when the torch crashes into something, it breaks...badly.
Perhaps it's original, perhaps its rigged, but there's a cage about 16" x 30" that hangs around the torch protecting a rectangular area around it....the idea being that if a part tips up, it hits the cage before the torch comes in range...the cage is on springs so moves easily. When it moves, it triggers a momentary contact switch...limit switch of sorts, triggering a stop.
This does not prevent a part right next to the torch and inside the cage (it's really just a single bar of steel bent into a rectangle) from causing major issues.
There is a place on the outside of the torch holder frame where I *could* mount a breakaway torch holder...do such things exist? There's going to have to be some custom fitting it, but no rocket science...torch hangs from above, cable suspended....lots and lots of beautiful slack to play with.
They've ruined two torch bodies this month due to this problem. Any and all thoughts or suggestions would be most welcome. Cost is a constraint (i.e. replacing the THC is not an option). It's a hypertherm 260 btw. There is a switch that can be actuated by motion...to trigger shutdown. That switch can also be replaced.
seconded what Carl said. The snap 'n cut is clean simple and repeatable.
The SnapnCut design is nice...but it is designed to handle an air plasma torch....which is lightweight and has a diameter of 1-3/8". The Farley machine, which uses Hypertherm's high definition class industrial torch....which is a liquid cooled 2" diameter torch will need a heavy duty solution for a torch breakaway.
Many industrial cnc plasma's use a pneumatic breakaway like the ones offered from a company called Applied Robotics Applied Robotics: Solutions in reach | Collision Sensors
This device uses adjustable air pressure to control the breakaway force and also has a built in switch that is wired into the machine so that when it breaks away it will do a quick motion stop of all machine axis. Hypertherm used this breakaway on its height control systems for years.
On Hypertherms newer technology height controls/torch mount systems....a magnetic breakaway of a heavier design (as compared to the SnapnCut) is utilized...and it also has a breakaway switch that is used to freeze motion on the machine.
Hope this helps.
Jim Colt Hypertherm
You may also want to check out plasmatorchprotectionsystem.com
This company offers a non brake away plasma/oxy-fuel torch holder, check out there video, when the torch comes into contact with a obstruction it simply swings back out of the line of travel.
It has a built in micro switch that can be wired to stop gantry movement and arc.
or shut off an oxy-fuel torch as well.
It has a built in torch bevel system that allows you to bevel line cut at 15,30 and 45 degrees.
We installed one on our Plasma cam and love it.