On Monday 22 November 2021 07:07:45 Gregg Eshelman via Emc-users wrote: > How about an eddy current brake that uses a thick copper washer, a > disk with some strong magnets, and use a small air cylinder to push > the copper washer away from the magnets and springs to pull or push it > close to the magnets when the air is cut off so the wrench stops fast.
Since eddy currents are speed sensitive, I see no need to disengage. what I do see is a lack of space to build it in since its effect would need a larger diameter copper disk than there is room for in Johns wrench mount. Lurking in the back of my mind is a very short pulse of air in fwd to stop the overspin once its unlocked. The air valve I am using to switch the mister air on the 6040 may be different from the one John is using, this one stops by venting the pressure in the out port to atmosphere with a pop, and I got it from some outfit that specializes in air horns for large cars. It may be that the venting would stop most of the overspin. Its only problem is that I don't think the coil maker figured on CCS operation as it runs way hotter than that famous little red wagon when its been on for 45 minutes. I've no clue if a bidir valve that does that is available. Something else for John to investigate. I think a 2 spool could do it, one to control the air, feeding one to do the reversal. My guess is that the one doing the reversal probably can't switch while the pressure is on. Oneshots in the hal file can fix that so I don't see that as a real problem. But you get that eddy current braking effect for free by using the battery impact screwdriver because the bts-7960 crowbars the motor in the off mode. You can turn it by hand, but not very fast. From wide open to stopped is about 1 turn. > Automatic brake release and fail safe engagement, but zero contact so > there's nothing to wear out or jam up. > > On Sunday, November 21, 2021, 07:57:34 AM MST, Gene Heskett > <ghesk...@shentel.net> wrote: Close to the truth, However there might > be a salvation in a viscous greased disk that would absorb the rapid > spin, trapped between two other disks. It would allow the initial slow > unlocking but seriously impede the following rapid spin. Or an eddy > currant brake but that would take burn it up power so it would need to > be applied only when the air is applied, and possibly for half a > second after the air valve was turned off. I like the suicide braking > idea, but there is limited space and it needs more diameter than you > have room for. A coil spring anchored to the tool that would allow > maybe three turns of the socket before winding tight against the > socket OD might be a softer stop. Or a pile of interlocking disks that > were screw driven like the rear brakes on an old Schwinn bicycle? > That was fairly compact and lasted close to forever. > > Just tossing out ideas to see if one sticks. > > Cheers, Gene Heskett. > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
