Inventor
HEFFNER DONALD L
US7 patents
Patents
7 patentsUS4628959ADec 16, 1986
Vacuum check valve
GEN MOTORS CORP24 citations81
US4763689AAug 16, 1988
Vacuum check valve
GEN MOTORS CORP5 citations61
US4750516AJun 14, 1988
Vacuum check valve
GEN MOTORS CORP6 citations61
US4756333AJul 12, 1988
Vacuum check valve
GEN MOTORS CORP2 citations57
US4724867AFeb 16, 1988
Vacuum check valve
GEN MOTORS CORP6 citations57
US4750517AJun 14, 1988
Vacuum check valve
GEN MOTORS CORP1 citations51
US4856554AAug 15, 1989
Vacuum check valve and method of control
GEN MOTORS CORP1 citations45