#garfield Logs

Sep 24 2012

09:46 katsmeow-afk trying to find the words to make a better mental image than i can draw
09:46 katsmeow-afk you know what the crankshaft of a weedwhacker looks like
09:46 katsmeow-afk =|_
09:47 katsmeow-afk now suppose you wanted to connect two of those such that _|===|-
09:47 katsmeow-afk on the outer areas of === you put roller bearings rated for the task, on the center one is the gear to a gearbox
09:48 katsmeow-afk how do you mate the two oem shafts in that === area so they act as one?
09:49 katsmeow-afk you can't weld them, you can insert a few bolts and a few locator pins, you can groove the mated surfaces and install keys
10:00 katsmeow-afk this is what i come up with : http://designerthinking.com/images/steam/DSCF2990m.jpg
10:01 katsmeow-afk and then basically anywhere roll pins can be inserted, insert them
10:01 katsmeow-afk the dottted boxes at the ends of === are the bearings
10:04 katsmeow-afk the whole crank i would prefer to be two pieces, no more, just so it can be assembled with roller bearings and a gear between the two throws
10:05 katsmeow-afk while that looks busy for a pair of weedwhacker cranks, scale it up in your head to 3" dia crank and 6" stroke
10:07 katsmeow-afk room for 3 keys in there, and many pins, and at least 3 bolts thru each end (and then slide the bearings over to the throws, covering the bolts)
10:08 katsmeow-afk the design eliminates shaft changes in the stress level in the combined shaft, but i believe it's adequate against a lot of torque
10:08 tsmeow-afk sits down and awaits comm
10:09 katsmeow-afk oh, the throws are at 90 degrees to each other
10:10 katsmeow-afk oh, counterweights not considered at this point, i goto the extreme and think they can be bolted on later, this is a prototype in my head
20:17 katsmeow-afk <poke><poke>
22:14 rue_house oh
22:16 katsmeow-afk oh yeas,, 24 hrs later.....
22:16 rue_house I'll catch up in a bit