RotationStopper

This is an entry for the Bike Motor Rotation Stopper Challenge. Having examined several bicycles, I noticed that the bottom edge of the bottom frame tube is normally tangential to the bottom bracket. Thus, the simplest solution to a universal rotation stopper is to utilise this observation. By extending the contact point with the frame away from the bottom bracket vertex, the forces incident on the bike frame are reduced, instead being taken by the rotation stopper bracket. If the motor produces a torque of 44Nm, with the arms at 260mm long, the force incident on the frame with the motor driving is about 170N. In your original design, and most of the other entries this increases to, up to 850N - which is more likely to damage or fatigue the frame. Unfortunately, the assembly model provided for the challenge caused Solidworks to crash! The original anti rotation bracket however did load - so this was used to determine centres for the fixing holes etc. Any of the dimensions, for example the width of the bottom bracket tube can easily be changed in the Solidworks model if not accurate. The new bracket itself is intended to be folded from 3mm mild or stainless steel. It incorporated two folded edges, which should be welded at the join as well as a 17mm cylindrical spacer to pick up the second attachment point on the motor. The bracket is intended to be fixed to the frame with a plastic clip known as a 'Herbie Clip' available as a standard part. See: http://www.zeroclips.com/products/HCL/HERBIE-CLIP-The-double-grip-hose-clip.html . It incorporates a slot for this to pass through and should be isolated from the frame with a rubber pad (shown in the renders). The force pushing the bracket on the frame will be greater than that pulling against the clip as this is only due to the drag in the motor (which I would hope is low otherwise you wouldn't be able to pedal it!). Thus, the clip is only to hold it in position rather than restrain any significant force. As I said above,