Harmonic drive vs Ferguson's Mechanical paradox
Harmonic drive vs Ferguson's Mechanical paradox
(OP)
Is/was the harmonic drive a descendant of Fergusons idea?
Harmonic drive>http://en.wikipedia.org/wiki/Harmonic_drive
Skip to 6.50 in the video below for what I think is Fergusons doing, but Im not sure if Ferguson ever had an outer gear ring in his plans. But, looking at the drawing below, gears f + h could be the outer rings but just in a different form.
Video,
ht tp://www.y outube.com /watch?v=t tfPo773HEU &featu re=related
Original plans/idea
http://c hestofbook s.com/craf ts/popular -mechanics /Amateur-W ork-4/Ferg uson-s-Mec hanical-Pa radox.html
Both the above are 'similar', in that they use 1 or more teeth less for operation.
Could the harmonic drive invention have been a copy of Ferguson's idea?
Another example of Fergusons idea
ht tp://www.y outube.com /watch?v=v WNLDgU6Xl4 &featu re=related
The reason I ask all this is because Im currently designing a servo powered 4th rotary axis for a cnc machine table and Im getting confused as to where one design starts, and the other stops.
Granted, the harmonic drive due to its design is '0' backlash, but with Fergusons example in the last video posted above, you could fit heavy springs between both gears similar to a scissor gear?
With that In mind, Im thinking torque losses would be similar for both designs, since the harmonic drive 'basket' has to deform while rotated.
Harmonic drives fetch around 3keuro which is why I ask all this.
Perhaps I should just scrap all my thinking, and go with a worm.
That has its downfalls too though.
Interesting stuff for sure,
Thanks in advance for any pointers,
Brian,
Harmonic drive>http://en.wikipedia.org/wiki/Harmonic_drive
Skip to 6.50 in the video below for what I think is Fergusons doing, but Im not sure if Ferguson ever had an outer gear ring in his plans. But, looking at the drawing below, gears f + h could be the outer rings but just in a different form.
Video,
ht
Original plans/idea
http://c
Both the above are 'similar', in that they use 1 or more teeth less for operation.
Could the harmonic drive invention have been a copy of Ferguson's idea?
Another example of Fergusons idea
ht
The reason I ask all this is because Im currently designing a servo powered 4th rotary axis for a cnc machine table and Im getting confused as to where one design starts, and the other stops.
Granted, the harmonic drive due to its design is '0' backlash, but with Fergusons example in the last video posted above, you could fit heavy springs between both gears similar to a scissor gear?
With that In mind, Im thinking torque losses would be similar for both designs, since the harmonic drive 'basket' has to deform while rotated.
Harmonic drives fetch around 3keuro which is why I ask all this.
Perhaps I should just scrap all my thinking, and go with a worm.
That has its downfalls too though.
Interesting stuff for sure,
Thanks in advance for any pointers,
Brian,





RE: Harmonic drive vs Ferguson's Mechanical paradox
Mike Halloran
Pembroke Pines, FL, USA
RE: Harmonic drive vs Ferguson's Mechanical paradox
Do you mean just a 'basic' stepped down pulley drive setup, or is there a way to use the timing belt as a form of ring gear around the planets that Im not seeing?
Thanks,
Brian,
RE: Harmonic drive vs Ferguson's Mechanical paradox
Harmonic drives are efficient, at least when transmitting maximum power, and worm gears are cheap, and they mostly are self locking at harmonic drive ratios. Which do you want?
The harmonic drives are zero backlash because the wave generators are springy. There are harmonic drive like systems that do have backlash. There is elastic wind-up in a harmonic drive. When I asked them, they told me they could ship their system with a chart showing gear tooth error on that particular one.
On the system I designed, I did not order a gear reducer. I ordered a gear-set, and I integrated this with bearings and a motor to get a very compact drive. Overall, I may even have saved the company money, by eliminating extra bearings, stub shafts and couplings and structure to mount them. Harmonic drive sets are now available integrated with crossed roller bearings.
Again, what do you want to accomplish?
RE: Harmonic drive vs Ferguson's Mechanical paradox
Mike Halloran
Pembroke Pines, FL, USA