Safety release mechanism for use with a linear motor turning a ball screw
A safety release mechanism for use with a ball screw type linear motor, featuring a lock lever that can be manually engaged or disengaged. Engaging the lock lever rigidly fixes a telescoping arm, allowing the motor to retract or extend the arm into a cover tube. Disengaging the lock lever allows the telescoping arm to rotate freely in the cover tube. One embodiment of the safety release mechanism is used with a motorized door assist mechanism, however, the release mechanism has many applications beyond a door opener, and can be used in any application requiring a linear motor with a telescoping arm, where in order for the motor to extend or retract the arm, one end of the arm must be fixedly held in place.
1 . A safety release mechanism ( 30 ) for use with a linear motor ( 60 ) having a telescoping arm ( 52 d ) extending into and retracting out of a cover tube ( 52 c ), the telescoping arm being fixedly held at a first end ( 52 a ) of the motor to a fixed member ( 50 ) when the motor is operational, the safety release mechanism comprising:
a non-rotatable interior assembly ( 80 ) comprising a Heim joint coupler assembly ( 20 a ) having a first end ( 22 a ) and a second end ( 22 b ), a Heim joint ( 20 ) nestled inside an opening in the first end ( 22 a ) and an end cap ( 37 ) screwably attached by an end cap screw ( 22 ) to the coupler assembly second end ( 22 b );
a rotatable exterior assembly ( 23 ) comprising a housing ( 24 ) having a proximal end ( 24 b ) and a distal end ( 24 c ), the assembly ( 23 ) screwably attached at the proximal end to the telescoping arm ( 52 d ) at the motor first end ( 52 a ) by an actuator attachment ( 26 );
a plurality of mechanism bearings ( 28 ) disposed inside the housing ( 24 ) and surrounding the coupler assembly ( 20 a ); and
a release lever ( 32 ) attached to the Heim joint coupler assembly ( 20 a ) at the housing distal end ( 24 c );
wherein the exterior and interior assemblies meet at a center gap ( 24 a ) defining an interface within the mechanism ( 30 ) between the rotatable and non-rotatable assemblies; and
wherein the housing ( 24 ) further comprises at least one notch ( 36 ) at the distal end ( 24 c ) of the housing ( 24 );
whereby the lever ( 32 ) engaging the at least one notch ( 36 ) locks the exterior and interior assemblies together, coupling the Heim joint ( 20 ) to the fixed member ( 50 ) and allowing the motor to extend and retract the telescoping arm ( 52 d ) out of and into the cover tube ( 52 c ), and disengaging the lever from the at least one notch decouples the Heim joint ( 20 ) from the fixed member ( 50 ) by allowing the exterior assembly ( 23 ) and telescoping arm ( 52 d ) to freely extend into or retract out of the cover tube ( 52 c ) without the aid of the motor.
2 . The safety release mechanism ( 30 ) of claim 1 , further comprising at least one cable pull ( 34 ) for mechanically engaging or disengaging the lever ( 32 ).
3 . The safety release mechanism ( 30 ) of claim 1 , wherein the mechanism ( 30 ) is a component of a door assist mechanism ( 100 a ).
4 . The safety release mechanism ( 30 ) of claim 1 , wherein the linear motor ( 60 ) extends or retracts the telescoping arm ( 52 d ) by turning a ball screw.