Tiggersmom

I have my mothers Old Kenmore, Model 1913/1815 which says to "pull" the wheel out to wind the bobbin then push it in when finished to start sewing.
The problem is the wheel won't pull out. I can unscrew the the small screw on the shiney silver end but I'm afraid to take it all the way out. Is it safe to do so and do I need to oil something inside???
I've done very few mechanical service/repairs so any Help will be appreciated!

Thanks, and have a blessed day, Jennifer