Triple spring torque motor

A video display unit for being attached to a structure, said display unit being constructed to stow and expose a video display device to a viewer, said display unit comprising:

• a frame;
• a monitor operatively connected to said frame such that said monitor can move from a first position to a second position relative to said frame, wherein said monitor is stowed within said frame in said first position and said monitor is exposed to a viewer in said second position such that the viewer can view said monitor;
• an actuator operatively connected to said frame and said monitor, said actuator having a ball screw that rotates in a first direction such that said monitor moves from said first position to said second position;
• a spring motor operatively connected to said frame having at least two parallel torsional springs attached to an output shaft such that said torsional springs turn in a first direction when said output shaft is turned in said first direction;
• coupling means operatively connected to said ball screw and said output shaft, such that said torsional springs turn a predetermined number of turns in said first direction when said ball screw rotates in said first direction moving said monitor from said first position to said second position;
• and,
• drive means operatively connected to said actuator adapted to apply a first torque to said actuator to rotate said ball screw in said first direction to move said monitor from said first position to said second position;
• whereby when said monitor is in said second position and said drive means does not apply a torque to said ball screw, said torsional springs turn said predetermined number of turns in a second opposite direction rotating said output shaft and said ball screw in said second opposite direction moving said monitor from said second position to said first position,

A video display unit for being attached to a passenger compartment of an airplane such that the display unit stows and exposes a video display device to a viewer, comprising:

• a frame;
• a monitor pivotally attached to said frame such that said monitor can rotate from a first position to a second position relative to said frame, wherein said monitor is stowed within said frame in said first position and said monitor is exposed to a viewer in said second position such that the viewer can view said monitor;
• an actuator pivotally attached to said frame and said monitor, said actuator having a ball screw that rotates in a first direction such that said monitor moves from said first position to said second position;
• a spring motor pivotally attached to said frame and said monitor having at least two parallel torsional springs attached to an output shaft such that said torsional springs turn in a first direction when said output shaft is turned in said first direction;
• coupling means operatively connected to said ball screw and said output shaft, such that said torsional springs turn a predetermined number of turns in said first direction when said ball screw rotates in said first direction moving said monitor from said first position to said second position;
• and,
• an electric motor operatively connected to said actuator adapted to apply a first torque to said actuator to rotate said ball screw in said first direction to move said monitor from said first position to said second position;
• whereby when said monitor is in said second position and said electric motor does not apply a torque to said ball screw, said torsional springs turn said predetermined number of turns in a second opposite direction rotating said output shaft and said ball screw in said second opposite direction moving said monitor from said second position to said first position.

A method of retracting a video display device into a stowed position of a display unit when electrical power to the display unit is terminated, comprising the steps of:

• providing a frame;
• pivotally attaching a monitor to said frame such that said monitor can rotate from a first position to a second position relative to said frame, wherein said monitor is stowed within said frame in said first position and said monitor is exposed to a viewer in said second position such that the viewer can view said monitor;
• pivotally attaching an actuator to said frame and said monitor, said actuator having a ball screw that rotates in a first direction such that said monitor moves from said first position to said second position;
• and,
• pivotally attaching a spring motor to said frame and said monitor having at least two parallel torsional springs attached to an output shaft such that said torsional springs turn in a first direction when said output shaft is turned in said first direction;
• operatively connecting a coupling means to said ball screw and said output shaft, such that said torsional springs turn a predetermined number of turns in said first direction when said ball screw rotates in said first direction moving said monitor from said first position to said second position;
• operatively connecting an electric motor to said actuator adapted to apply a first torque to said actuator to rotate said ball screw in said first direction to move said monitor from said first position to said second position, said electric motor being adapted to apply a second torque to said ball screw in a second opposite direction to move said monitor from said second position to said first position;
• energizing said electric motor such that said electric motor applies said first torque to said ball screw, wherein said monitor is moved from said first position to said second position;
• and,
• de energizing said electric motor such that there is no torque applied to said ball screw;
• whereby said torsional spring turns said predetermined number of turns in said second opposite direction rotating said output shaft and said ball screw in said second direction such that said monitor moves from said second position to said first position.