Kenmore 1347 Instructions Manual page 19

In addition to the obvious controls of your machine, there are other small
regulators and controls to aid you in using your sewing machine
Push down the outer ring of the pressure regulator This will release the
pressure on the presser foot. (See above)
To increase the pressure, push down inner pin until a suitable pressure is
obtained,
Insufficient pressure may cause poor feeding of the fabric, skipped stitches,
or difficulty in guiding the fabric If feed dogs or presser foot marks appear
on the fabric, reduce the pressure
When sewing multiple thickness or heavy fabric, reduce the pressure, Increase
pressure when sewing lighter weight fabrics