Actuator with ball screw drive

A kit for installation in a door latch system including a latch device configured for motion between a latched position and an unlatched position when installed in a door having a first side and a second side, and a mechanical apparatus coupled to the latch device and configured to move the latch device to the unlatched position in response to force manually applied by a user to a component of the mechanical apparatus, the kit comprising:

• an electromechanical actuator system configured for coupling to the latch device to move the latch device to an actuator unlatched position in response to an electrical signal from an access control device, the electromechanical actuator system including a control module, a motor with a motor shaft, and a mechanism to translate the rotational output force of the motor to a force to actuate the latch device;
• wherein the mechanism comprises a ball screw drive comprising a ball screw and a threaded nut, and wherein one of the ball screw or threaded nut is configured for coupling to the latch device or mechanical apparatus and constrained from rotation, and the other of the ball screw or threaded nut is coupled to the motor shaft, and at least one recirculating ball circuits including ball bearings for transferring torque from the motor to drive the one of the ball screw and nut along an axis of the ball screw.

18-22. (canceled)