Yes, I know, how boring - but if you don't clean out the lint from your sewing machine from time to time, it can jam up and cause problems. Check your sewing machine manual from instructions on how to remove the bobbin holder and shuttle race. I have only had my new machine for a year and decided to clean these two places out, as I have done a lot of quilting this year. I found a very solid piece of lint inside!
Here is an interesting web site with free sewing patterns including a bag to hang from a walker or wheelchair.