Backpedal Brake: Post 3: "Deadman Release" and Bumper

[From Graham Butler March 15, 2011 Input from Bill Warner and a mechanical engineer in at a Cambridge rotary compressor company who suggested the "deadman switch" idea like on a chain saw.]

I just got back from Brazil at the end of last week, things got hectic the last couple of weeks before leaving.

I think that the last we left the design, we had talked about a 'deadman's switch' for the brake release.  It makes sense.  Check out the attached screen shots of my first hash.  It is very simple.

Talked to Seth today.  We are getting material ordered so that he can build front forks.  I figured that while some aspects of seating might change, it is very unlikely that the front fork geometry would change substantially.

Backpedal Brake: Post 1: Arms and Pins

[From Graham Butler January 31, 2011]

(Editor's note: We began a series of designs aimed at allowing the backpedal-activated brake to be released so you you can ...for example... back out of an elevator without having the brake come on. This was the first of many designs, which we document for posterity...on Posterous.)

OK, so I have been going backwards and forwards all day with the rollback brake system.

I started with a counter cam to relieve the cable tension.  I think I have a system that would work.  It will engage when pedaling forward only and disengage manually.  I have attached screen shots.  My problem was that it seems very cumbersome and hard to fabricate with tough angles and lots of small parts.  It seemed to me that a simple pin system would be much more reliable, and easier to fabricate.  Screen shots are attached.

Goal is to have foward pedaling re-engage the brake.