US 12,266,918 B2
Constant-clutch operation at power tool start-up
Sona R. Mathew, Towson, MD (US); Daniel F. Nace, Towson, MD (US); Jason D. McKillican, Baltimore, MD (US); and Christopher T. King, Catonsville, MD (US)
Assigned to Black & Decker Inc., New Britain, CT (US)
Filed by Black & Decker Inc., New Britain, CT (US)
Filed on Sep. 20, 2022, as Appl. No. 17/948,356.
Prior Publication US 2024/0097431 A1, Mar. 21, 2024
Int. Cl. H02P 6/16 (2016.01); B25F 5/00 (2006.01); H02H 7/08 (2006.01); H02K 7/14 (2006.01); H02P 9/04 (2006.01); H02P 15/00 (2006.01); H02P 21/22 (2016.01)
CPC H02H 7/0822 (2013.01) [B25F 5/001 (2013.01); H02K 7/145 (2013.01); H02P 15/00 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A method of operating a power tool having a motor and a controller, the method comprising:
setting a protection time limit associated with a condition of the motor;
taking protective action to shut down the motor if the condition of the motor persists for a duration of the protection time limit; and
in response to occurrence of the condition during a start-up period of operation of the motor where an output speed of the motor is between zero and a minimum speed threshold, extending the protection time limit by a duration of a constant-clutch time period to allow an output speed of the motor to reach or exceed a normal operating speed threshold that is greater than the minimum speed threshold, and taking protective action to shut down the motor if the output speed of the motor remains below the normal operating speed threshold for the duration of the constant-clutch time period.