Powered fastener driver

A powered fastener driver comprising:

• a housing;
• a cylinder within the housing, the cylinder containing a pressurized gas;
• a piston within the cylinder and moveable from a top-dead-center position to a bottom-dead-center position;
• a driver blade moveably coupled to the piston for driving a fastener into a workpiece, the driver blade having a plurality of teeth;
• a lifter configured to sequentially engage the teeth for returning the driver blade from the bottom-dead-center position toward the top-dead-center position;
• a drive unit configured to provide torque to the lifter, causing it to rotate;
• a lifter sensor configured to detect an angular position of the lifter;
• a driver blade sensor configured to detect one or more of the plurality of teeth;
• and
• a controller in communication with the drive unit, the lifter sensor, and the driver blade sensor, the controller configured to:
• count a number of teeth detected by the driver blade sensor once the lifter sensor detects that the lifter moves through a nominal driver blade drop position,
• compare the number of detected teeth to a predetermined number of teeth, and
• stop the drive unit when the number of detected teeth is less than the predetermined number of teeth.

A powered fastener driver comprising:

• a housing;
• a cylinder within the housing, the cylinder containing a pressurized gas;
• a piston within the cylinder and moveable from a top-dead-center position to a bottom-dead-center position;
• a driver blade moveably coupled to the piston for driving a fastener into a workpiece, the driver blade having a plurality of teeth;
• a frame supported within the housing;
• a lifter supported within the housing by the frame and configured to sequentially engage the teeth for returning the driver blade from the bottom-dead-center position toward the top-dead-center position;
• a drive unit configured to provide torque to the lifter, causing it to rotate;
• a lifter position sensing assembly configured to detect an angular position of the lifter at an end of a fastener driving cycle, the lifter position sensing assembly including an inductive sensor coupled to the frame and a sensor target coupled for co-rotation with the lifter;
• and
• a controller in communication with the drive unit and the lifter position sensing assembly, the controller configured to stop the drive unit in response to the lifter position sensing assembly not detecting the angular position of the lifter at the end of the fastener driving cycle.