It is the out of balance trip lever. When the load is too heavy on one side it will bang around until it knocks the out of balance lever and stops the machine. The machine will still work without it but will not stop if out of balance. That machine is over 20 years old and F&P no longer supply parts for it. I have some of those levers left & can send you one if you are here in NZ
Lincoln Appliance NZ
April 2013