Hi Matt,
recumpence said:
Along with the next run of drives, I may make a mounting plate that the Foot can screw to. That mount plate would have a rounded under side to fit against a frame tube and have four holes along the sides for U-bolts. A rubber pad can be used between the plate/U-bolt assembly and the frame. I think this will tend to twist on the frame. So, I need to figure out a simple rotation brace to eliminate that from occurring. But, overall, this may be the easiest solution without having to throw another hundred bucks at it for CNC frame clamps.
Matt
I like it. Sounds excellent. Very little additional cost or complexity while at the same time making a huge reduction in the difficulty of mounting on many bikes!
Earlier post from another thread:
recumpence said:
I may make the next round of drive mounts wider, like the look of Gary's and Oof's mount with the angled side flanges (but integrated into the mount foot) and mill a rounded recess into the length of the foot mount in the center to rest against the frame or seat tube. Then the customer can just use U-bolts for mounting.
Matt
One thing I like about your earlier idea was the simplicity, no increase in parts count. I agree that rotation prevention is essential. Maybe borrowing a page from your earlier idea and doing something as simple as providing some flat surfaces with bolt holes on the foot, where the owner can easily mount a brace or braces. They can run the brace(s) to any nearby tube or surface and secure them with bolts or u-bolts.
I posted this image on D's thread and thought it might be of interest here, because both the "feet" in contact with the down-tube and the band clamp are possible solutions for non-round and varying sized down-tubes. I think the "feet" he uses in contact with the frame tube provide a good fit on a wider range of tubes than a round surface. Would something similar, maybe using longer pieces of thicker stock for "feet" work, or would they bend the frame?
http://www.bike-elektro-antrieb.ch/home.htm
If they could be made to work it might be possible to design a similar part on which the distances between the "feet" and the lengths of the "feet" could easily be varied to accommodate an even wider range to down-tube shapes and sizes. If the "feet" are made out of bolted on angle stock then both the distance between the "feet" and the height of the "feet" could easily be varied.
GGoodrum said:
recumpence said:
Maybe the U-bolts would not look out of place with purpose built drive foot specifically for them?
I think that would be fine. It's not the U-bolts I have a problem with, it is just my cheezy-looking, unpolished "wings".
When you do this, can you have some extras made? I'd like to get a couple of new "shoes" for my two existing drives.
-- Gary
Gary, your best bet is probably to wait for Matt's solution, but if you want U-bolt mounts that don't look like wings you could:
1. Make your extensions out of square or rectangular stock instead of angle stock so they look less like "wings". Maybe do some grinding to match the contours of the foot and/or bevel the top corner.
2. Start with square or rectangular stock and have the top corner machined off so that you have a sloping side instead of a 90 degree corner at the top.