Cranks spin forward without catching and chain not moving
I have an Autobike that I have ridden for about 18 years with no problems. It has helped me recover mobility after knee replacement, and am now riding it back and forth to work - the high school where I teach. This last week I began having a problem with my cranks and the local bike shop says They cannot fix or get the parts for it. I am looking for an autobike I can use for parts, or someone who can tell me where to go to get parts.
The crank spin forward and won't catch. The chain is not moving. This is intermittent. I go about a couple of miles toward school and then all of a sudden, I can pedal like crazy, but not get any thing to the sprocket. I walk the rest of the way to school, lock the bike up and do my job. Come out after school and ride like normal a mile or two and then it happens again.
How about it? Anyone help this old (61) Vet out? Anybody got any ideas?