Fail safe throttle positioning system

Abstract

A fail-safe throttle positioning device is disclosed for an engine induction system. A throttle body is provided having a fluid passage. A movable throttle valve is disposed within the fluid passage for at least idle speed control. An actuator mechanism is connected to the throttle valve for operably moving the throttle valve between a minimum fluid flow position and a maximum fluid flow position. A fail-safe mechanism urges the throttle valve toward an intermediate position between the minimum and maximum fluid flow positions to prevent inoperability of the engine during failure of the actuator mechanism.

1. A fail safe throttle positioning device for an engine induction system comprising:
 a throttle body having a fluid passage passing therethrough;    a movable throttle valve for controlling at least idle speed, said throttle valve mounted for movement with respect to said throttle body and disposed in said fluid passage for controlling fluid flow in response to movement of said throttle valve;    actuator means connected to said throttle valve for operably moving said throttle valve between a minimum fluid flow position and a maximum fluid flow position; and    fail safe means for urging said throttle valve toward an intermediate position between said minimum and maximum fluid flow positions to prevent inoperability of said engine during actuator means failure.    
     
     
       2. The device of  claim 1  wherein said actuator means further comprises:
 a rotatable shaft supporting said throttle valve within said fluid passage for rotational movement;    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; and    throttle spring means for normally urging said throttle lever toward said minimum fluid flow position.    
     
     
       3. The device of  claim 2  wherein said fail safe means further comprises:
 a fail safe lever mounted on said shaft for rotation independent of said shaft, said fail safe lever having a first surface engageable with said throttle lever and a second surface engageable with a fail safe stop; and    fail safe spring means for urging said fail safe lever toward said fail safe stop such that said throttle lever is held in said intermediate position until driven by said actuator means toward one of said minimum and maximum fluid flow positions.    
     
     
       4. The device of  claim 3  further comprising:
 a spacer sleeve mounted on said shaft external of said throttle body;    said fail safe spring means including a helical spring extending longitudinally over said spacer sleeve and having a first end connected to said throttle body and a second end connected to said fail safe lever;    spring bushings disposed at longitudinal ends of said fail safe spring and overlaying longitudinally at least a portion of said fail safe spring; and    said throttle spring means including a helical spring extending longitudinally over said spring bushings and having a first end connected to said throttle body and a second end connected to said throttle lever.    
     
     
       5. The device of  claim 1  wherein said actuator means further comprises:
 mechanically operated actuator means connected to said throttle lever and responsive to driver input.    
     
     
       6. The device of  claim 1  wherein said actuator means further comprises:
 electrically operated actuator means connected to said throttle lever and responsive to driver input.    
     
     
       7. 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.  
 
     
     
       8. The device of  claim 7  wherein said fail safe means further comprises:
 a fail safe lever rotatably mounted on said shaft, said fail safe lever having a first surface engageable with said throttle lever and a second surface engageable with a fail safe stop; and  
 fail safe spring means for urging said fail safe lever toward said fail safe stop such that said throttle lever is held in said intermediate position until driven by said actuator means toward one of said minimum and maximum fluid flow positions.  
 
     
     
       9. The device of  claim 8  further comprising:
 a spacer sleeve mounted on said shaft external of said throttle body;  
 said fail safe spring means including a helical spring extending longitudinally over said spacer sleeve and having a first end connected to said throttle body and a second end connected to said fail safe lever;  
 spring bushings disposed at longitudinal ends of said fail safe spring and overlaying longitudinally at least a portion of said fail safe spring; and  
 said throttle spring means including a helical spring extending longitudinally over said spring bushings and having a first end connected to said throttle body and a second end connected to said throttle lever.  
 
     
     
       10. The device of  claim 7  wherein said actuator means further comprises:
 mechanically operated actuator means connected to said throttle lever and responsive to driver input.  
 
     
     
       11. The device of  claim 7  wherein said actuator means further comprises:
 electrically operated actuator means connected to said throttle lever and responsive to driver input.  
 
     
     
       12. 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.  
 
     
     
       13. The device of  claim 12  wherein said fail safe means further comprises:
 a fail safe lever connected to said throttle valve means, said fail safe lever having a first surface engageable with said throttle valve means and a second surface engageable with a fail safe stop; and  
 said second helical spring means for urging said fail safe lever toward said fail safe stop such that said throttle valve means is held in said intermediate position until driven by said actuator means toward one of said minimum and maximum fluid flow positions.  
 
     
     
       14. The device of  claim 12  further comprising:
 said throttle valve means including a rotatable shaft;  
 a spacer sleeve mounted on said shaft external of said throttle body;  
 said second helical spring means including a fail safe helical spring extending longitudinally over said spacer sleeve and having a first end connected to said throttle body and a second end connected to said fail safe means;  
 spring bushings disposed at longitudinal ends of said fail safe helical spring and overlaying longitudinally at least a portion of said fail safe helical spring; and  
 said throttle valve means including a throttle return helical spring extending longitudinally over said spring bushings and having a first end connected to said throttle body and a second end connected to said throttle valve means.  
 
     
     
       15. The device of  claim 12  wherein said actuator means further comprises:
 mechanically operated actuator means connected to said throttle lever and responsive to driver input.  
 
     
     
       16. The device of  claim 12  wherein said actuator means further comprises:
 electrically operated actuator means connected to said throttle lever and responsive to driver input.  
 
     
     
       17. A fail safe throttle positioning device for an engine induction system comprising:
   a throttle body having a fluid passage extending through said throttle body;        a shaft extending across said fluid passage;        a throttle valve mounted on said shaft for rotation and 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 engagable with a first stop defining a minimum fluid flow position and a second surface engagable with a second stop for defining a maximum fluid flow position;        a throttle spring for urging said throttle lever toward said minimum fluid flow position;        an actuator connected to said throttle lever for operably moving said throttle lever against said urging of said throttle spring toward said maximum fluid flow position; and        a fail safe spring 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.     
     
     
       18. The device of  claim 17  wherein said actuator further comprises an electrically operated actuator connected to said throttle lever. 
     
     
       19. The device of  claim 17  wherein said actuator further comprises a mechanically operated actuator connected to said throttle lever. 
     
     
       20. The device of  claim 17  wherein said fail safe spring and said throttle spring are nested substantially within each other. 
     
     
       21. The device of  claim 17  wherein said fail safe spring and said throttle spring are nested at least partially within each other. 
     
     
       22. The device of  claim 17  wherein said fail safe spring and said throttle spring are axially juxtaposed to each other. 
     
     
       23. The device of  claim 17  further comprising a fail safe lever rotatably mounted on said shaft to rotate independently of said shaft, wherein said fail safe lever is positioned between said fail safe spring and said throttle lever so that said fail safe lever urges said throttle lever toward said intermediate position. 
     
     
       24. The device of  claim 17  further comprising:
   a fail safe lever rotatably mounted on said shaft, said fail safe lever having a first surface engageable with said throttle lever and a second surface engageable with a fail safe stop; and        wherein said fail safe spring is operably engaged to said fail safe lever and urges said fail safe lever toward said throttle lever such that said throttle lever is held in said intermediate position until driven by said actuator toward one of said minimum and maximum fluid flow positions.     
     
     
       25. The device of  claim 24  wherein said throttle lever and said fail safe lever are axially juxtaposed. 
     
     
       26. A fail safe throttle positioning device for an engine induction system comprising:
   a throttle body defining a fluid passage;        a throttle valve mounted for movement within said fluid passage to control fluid flow through said fluid passage by movement of said throttle valve;        an actuator connected to said throttle valve for moving said throttle valve between a minimum fluid flow position and a maximum fluid flow position in response to input signals;        a fail safe arrangement for urging said throttle valve toward an intermediate position between said minimum and maximum fluid flow positions to prevent inoperability of said engine during failure of said actuator, said fail safe arrangement including coaxial, first and second helical springs, said first helical spring for urging said throttle valve toward said minimum fluid flow position and said second helical spring for urging said throttle valve toward an intermediate position between said minimum and maximum fluid flow positions, said second helical spring applying greater force to said throttle valve than said first helical spring.     
     
     
       27. The device of  claim 26  wherein said actuator further comprises an electrically operated actuator operably connected to said throttle lever. 
     
     
       28. The device of  claim 26  wherein said actuator further comprises a mechanically operated actuator connected to said throttle lever. 
     
     
       29. The device of  claim 26  wherein said fail safe arrangement further comprises a fail safe lever mounted on said shaft to rotate independently of said shaft, wherein said fail safe lever is positioned between said second spring and said throttle lever so that said fail safe lever urges said throttle lever toward said intermediate position. 
     
     
       30. The device of  claim 26  further comprising:
   a fail safe lever rotatably mounted on said shaft, said fail safe lever having a first surface engageable with a throttle lever operably connected to said throttle valve and said actuator and a second surface engageable with a fail safe stop; and        wherein said second spring is operably engaged to said fail safe lever and urges said fail safe lever toward said fail safe stop such that said throttle lever is held in said intermediate position until driven by said actuator toward one of said minimum and maximum fluid flow positions.     
     
     
       31. The device of  claim 30  wherein said throttle lever and said fail safe lever are axially juxtaposed.