Thread: shafts, gears and wheels....
View Single Post
  #10   Spotlight this post!  
Unread 24-06-2002, 04:09
archiver archiver is offline
Forum Archival System
#0047 (ChiefDelphi)
  
Join Date: May 2001
Location: Pontiac, MI
Posts: 21,214
archiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond reputearchiver has a reputation beyond repute
Spiral Definition
Posted by Dodd Stacy at 05/12/2001 10:44 AM EST


Engineer on team #95, Lebanon Robotics Team, from Lebanon High School and CRREL/CREARE.


In Reply to: Re: Well Said, Joe
Posted by ChrisH on 05/11/2001 3:51 PM EST:




: Would you care to elaborate on the spirals? A name or better yet an equation would be helpful. I've been playing with involutes lately for gears, is this what you mean?

: ChrisH

The spiral is defined in polar coordinates by:

THETA = [(R/Ri)^2 - 1]^1/2 + Arcsin (Ri/R) - (pi/2),

where Ri is some initial non-zero radius and serves to scale the curve. I don't know whether this family has a name - I couldn't find one.

The attribute of the curve is that when it is rotated and repeated, the local perpendicular distance between the two curves is constant along their full length. If "male" and "female" surfaces are used in a spline arrangement to transmit torque, the elastic compressive strain perpendicular to the surface is also constant along the length of the curve, so the stress is likewise uniformly distributed. No part of the stressed interface yields early.

If you have access to the patent office database, US # 5,957,645 describes application of this shape to the driving of recess head threaded fasteners. We found we could apply more than twice as much torque to aircraft threaded fasteners w/o damaging the screw head or tool as was possible without destroying the best existing commercial drive system (Torq Set tm). This has positive impact in MRO of aircraft.

Dodd



__________________
This message was archived from an earlier forum system. Some information may have been left out. Start new discussion in the current forums, and refer back to these threads when necessary.