Courtesy of Tim Sexton, here's some pics and commentary from Paul at Paul Components, concerning the history of brake design at Paul, and some of the prototypes he's produced over the years...
Glad you like the Crosstops. Thanks. Those who mastered the setup procedure say the same thing.
The brake with the plate and roller [bottom left corner] was my mechanical engineering senior project in college. I guess it was predetermined I would wind up making bike brakes.
The funny looking black one [2nd from top left corner] was the precursor to the Crosstop. housing ended at the top of the arm and the cable continued on down and into a hole in the bottom of that cam thing. There was a cable clamp that fit in the round recess. Then there was a short cable that went from the top of that cam thing to the other arm, round cable clamps on both ends. It worked ok but when I saw the IRD version I knew it was better. I called them up (Rod and Ray) and asked if they would pissed if I did a similar version. We've been friends ever since. (A side note-Syncros toured their shop and then promptly ripped off their seat post design-without asking the same question-they are not friends.)
The silver canti [2nd from bottom left corner] was my second attempt at canti's. The first was in high school, and it was a true hack job.All through high school and college I worked in bike shops on the early mtb bikes. Those brakes all had the concave/convex system using an eye bolt. They all sucked, mostly because they were so cheaply made. I knew there was a better way, and it involved something round.
With my brakes I put the pad in split sphere. You set the pad and tighten the screws on the top and bottom which squeezed the two brake plates (like Mafacs) to squeeze the ball which squeezed the pad post. Worked ok but the threads stripped and I could not make them on a production basis. This was before I had cnc's and it was all done on an old mill in my garage when I got home from working at Mountain Goat. I also made a u-brake version-and now I am doing one again! the Racer.
I also want to say something about the v-brake on top left [top left corner]. I made it [circa 1989!] for Mtn Goat - they wanted to get into the hot market of purple components. It required a new long pull lever, which was out of my means. I designed one and it was wild. It had a cam that pushed on the housing, as well as pulled the cable. Ha! Crazy.
It was way before Shimano's. Then suspension came along and the need to get rid of the housing stop so I did the Crosstop. Then Ben (who is now a big wig at Specialized) did the Cheap Trick and the rest is history.
Have a good ride,
Paul