Electrical solenoid actuator power increased to 50W continuous duty (from 10W), and the 1" stroke limit was removed. (from R501)
I haven’t worked much with solenoids beyond their application with pneumatics. My question is… Could a solenoid (itself, without pnematic) now be strong enough to provide the force for a climber brake? When power’s cut, does (can) a solenoid stay in position? I’ve read some stuff and watched some videos, and it’s still not clear to me whether the application is possible… I assume someone with experience can explain. Thanks!
Really depends where it is on the system: acting as a disk brake on a 2’ diameter disk? Sure. Acting on a neo vortex outrunner (with pad) on a 100:1 reduction? Sure. Trying to press against a climber in a box drum? No.
Spring load it so the spring provides the force (friction pad style) or to push a locking pin in somewhere. Then all you need to do in energize it while you climb, so it will only be powered for a few seconds.
We’re planning to use the brake mode of 2 motors (@25:1 or 20:1) with our elevator-based climbing solution. This is contingency planning because we haven’t had a chance to test yet.
I was thinking about using a solenoid to actuate the caliper of a mechanical disc brake set up on the lower shaft of an elevator, but I’m not sure about fitting a disc with large enough diameter for it to work well.
I did also think about the locking pin approach, but it seems like there’s a risk of the pin not lining up with a hole if the holes are in a disc on the shaft, though with motors in brake mode, the disc would be slowly rotating so the pin would slide into place within a moment’s time.
I’m pretty sure there’s a little battery-powered solenoid in the num-key lock on my house’s front door, come to think of it. I think using a solenoid like this could work.
If anyone’s done it, would love to see how you put it together. Thanks.
Yup, If it is spring loaded (most solenoids are by default ) so it is nominally pushing towards the face of the material with the slot in it it should snap into place. You only power the solution when you run the climb motors .
Another solution is use the solenoid (or servo) to release a plastic (polycarbonate ) hook that flips up and over the chain. The base of the hook is on a stationary part of the elevator so when the hook bears weight it reduces the load on the motors back driving until you reach equilibrium.
Definitely, going from10W to 50W opens up a lot of possibilities. Some solenoids are sprung to be bistable, though by default no force is applied when the current is off.
A big thing to remember about a solenoid is that other than the [usually fraction of a second] that the magnet or iron rod is moving, the solenoid is much like a motor in stall state - every bit of current you put into it is turned to heat, so for both heat management and battery management purposes, you want to keep the actuation time brief.
While most solenoids just have an iron rod, allowing force to be applied in one direction, some have a permanent magnet inside, meaning that by reversing the current (you’ll need a Spike or Motor Controller to legally do this), you can intentionally switch a bistable solenoid similar in effect to how you use a double solenoid pneumatic valve.