On 14 May 2012 06:00, charles green <xxzzb...@yahoo.com> wrote: > i wonder, in the ball worm mechanism, why not make the worm engagement happen > over more like a quarter of the diameter of the gear.
This can be done, to an extent, with conventional worms, but it gets a bit difficult as eventually you have to teleport the parts into mesh, or lose the advantage of increased engagement. (ie, assembly becomes impossible). They are called "enveloping" or "hourglass" worms. I think David Brown hold the patents, and market as "Cone Drive" http://www.directindustry.com/prod/cone-drive-gearing-solutions/worm-gears-16379-491012.html I believe that there are drives which use half of the hourglass to make assembly easier. The ball-worm has an advantage there, as you can put the balls in second, and so there isn't the same shape-locking problem. Where I do see an issue is in the required tooth profile in the wheel, which needs to be correct both at the large ends and small middle of the hourglass. My feeling is that the helix angle varies, which might make things difficult. (Maybe the angle doesn't change, as the track becomes tangential) -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
