On Sunday 21 November 2021 03:24:24 John Dammeyer wrote: > Actually that is along the lines of what I've asked. Some sort of > brake that could limit the speed. > > If you go back to steam engines the two weights swung out and shut off > the pressure to the engine to keep it from running away. I'm not sure > I could fit something like that in that space but I had an idea like > that. > > Occasionally, until I solve that problem the socket goes flying off > too. The square shaft of the wrench is hardened and I've used a > Dremel to create a dimple but it's not deep enough yet. Adding a > guard around the socket for safety is a good idea then. And if > centrifugal force causes two arms with brake pads to fly out and run > against the guard to slow it down that would work. But seems overly > complex. > > Using that same guard idea but with pads that apply load to the socket > to keep it from spinning away might be easier. If you think about the > sound of an impact wrench it spins up and only when it hits a load do > you get the hammering sound. > > I've been considering this as a solution instead. > https://www.aliexpress.com/item/4000220757109.html > > John > Even at 10/1, I doubt it could generate enough closing torque. The air wrench is probably too much anyway. It can probably strip the drawbolt
I use a 20 volt battery powered Porter Cable impact screwdriver which has plenty of closing torque due to its impact, and my reflexes are fast enough to prevent the overspin and r8 collet drop. I don't see why that idea couldn't be timed to turn it off when the magnet comes by the second time. An H bridge such as the $7 ebay thing I used to drive that BS-1 clone can switch 25 volts at 43 amps, shouldn't have a problem replacing the trigger switch and would also serve as the reversing switch without having to punch the direction button. Total electric conrol by a pair of signals from the bob, crowbarring the motor to stop it quick. Controls for that are a 30 minute edit and test in linuxcnc. Unless busier than that cat on that famous tin roof, charge/swap the battery about monthly. On my g0704, about a seconds hammering and theres no tool slippage, 10 seconds would likely strip or break the drawbolt. Put the H bridge right on the tool so 10 gauge leads are short for low loss. Since you have the air rigged to drop/lift it, keep that but I'd tally the down position and interlock the logic so the only thing you could do when its up, is position it to put the magnet in the correct position for the next unlock cycle. Your pix gives me an idea to make the engagement slider out of an old plunge router base, printing a collar to adapt the impact tool to the router base. All I'd need is the giddyup to get off my duff and do it. But first, straighten the crooked post on that BBLB POS. Until I do that, its looking to be replaced and used for salvage. > > -----Original Message----- > > From: Roland Jollivet [mailto:roland.jolli...@gmail.com] > > Sent: November-21-21 12:14 AM > > To: Enhanced Machine Controller (EMC) > > Subject: [Emc-users] Closed loop control of air motors. > > > > It's not what you asked, but what about a centrifugal > > clutch/limiter? Above say 200RPM it could swing outwards and lock, > > only releasing again once the torque is removed. > > > > On Sun, 21 Nov 2021 at 09:45, John Dammeyer <jo...@autoartisans.com> wrote: > > > Has anyone ever tried any sort of closed loop control of an air > > > motor similar the one on this butterfly impact wrench. > > > https://www.penntoolco.com/52-424-9/ > > > In order to not have both the TTS and R8 collet drop out of the > > > spindle I'd like to be able to limit the number of turns to 2. > > > > > > What I've found however, is that 10mS pulses to the valve > > > supplying air for CCW rotation barely move it until it's unloaded > > > and then it immediately spins up very fast and does at least 4 to > > > 8 turns. That's way too many. > > > > > > I've only got a one pulse per rev hall sensor detecting a magnet > > > on the socket. But I suspect between reaction time of the valve, > > > the compressibility of air and the rotary inertia of the motor > > > that unless there is some sort of constant load that control is > > > pretty well impossible. > > > > > > With servos, if the motor is loaded and then suddenly totally > > > unloaded, it too might turn a number of revolutions before the > > > control system could bring it back down to the original speed. > > > > > > Short of adding some sort of mechanical brake am I trying to do > > > the impossible? Oh and to avoid another 1000 words to explain > > > I've added a picture. > > > John > > > > > > _______________________________________________ > > > Emc-users mailing list > > > Emc-users@lists.sourceforge.net > > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > _______________________________________________ > 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
