Fail safe throttle positioning system

A fail safe throttle positioning device for an engine induction system comprising:

• a throttle body having an elongated fluid passage extending therethrough with a longitudinal axis;
• an elongated shaft having a rotational axis generally perpendicular to said longitudinal axis of said fluid passage;
• a throttle valve mounted on said shaft for rotational movement therewith and disposed within said fluid passage for controlling an amount of fluid flow through said fluid passage in response to rotational movement of said shaft;
• a throttle lever connected to said shaft for rotation therewith, said throttle lever having a first surface engageable with a first stop defining a minimum fluid flow position and a second surface engageable with a second stop defining a maximum fluid flow position;
• throttle spring means for normally urging said throttle lever toward said minimum fluid flow position;
• actuator means connected to said throttle lever for operably moving said throttle lever against said urging of said throttle spring means toward said maximum fluid flow position;
• and
• fail safe means for urging said throttle lever toward an intermediate position between said minimum and maximum fluid flow positions to prevent inoperability of said engine during failure of said actuator means.

A fail safe throttle positioning device for an engine induction system comprising:

• a throttle body defining a fluid passage;
• throttle valve means for controlling at least idle speed, said throttle valve means mounted for movement within said fluid passage to control fluid flow through said fluid passage by movement of said throttle valve means;
• actuator means, connected to said throttle valve means, for moving said throttle valve means between a minimum fluid flow position and a maximum fluid flow position in response to input signals;
• fail safe means for urging said throttle valve means toward an intermediate position between said minimum and maximum fluid flow positions to prevent inoperability of said engine during failure of said actuator means, said fail safe means including coaxial, counteracting, first and second helical spring means, said first helical spring means for urging said throttle valve means toward said minimum fluid flow position and said second helical spring means for urging said throttle valve means toward an intermediate position between said minimum and maximum fluid flow positions, said second helical spring means applying greater force to said throttle valve means than said first helical spring means.