US 12,240,085 B2
Systems and methods for detecting anvil position using an inductive sensor
Jacob P. Schneider, Cedarburg, WI (US); Douglas R. Fieldbinder, Greendale, WI (US); and Maxwell L. Merget, Milwaukee, WI (US)
Assigned to Milwaukee Electric Tool Corporation, Brookfield, WI (US)
Filed by MILWAUKEE ELECTRIC TOOL CORPORATION, Brookfield, WI (US)
Filed on Jun. 4, 2021, as Appl. No. 17/339,820.
Claims priority of provisional application 63/125,705, filed on Dec. 15, 2020.
Claims priority of provisional application 63/034,727, filed on Jun. 4, 2020.
Prior Publication US 2021/0379743 A1, Dec. 9, 2021
Int. Cl. B25B 21/02 (2006.01); B25B 23/147 (2006.01); G01D 5/20 (2006.01); H02K 7/14 (2006.01); H02K 11/21 (2016.01); H02K 11/33 (2016.01); H02P 6/16 (2016.01)
CPC B25B 23/1475 (2013.01) [B25B 21/02 (2013.01); G01D 5/204 (2013.01); H02K 7/145 (2013.01); H02K 11/21 (2016.01); H02K 11/33 (2016.01); H02P 6/16 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A power tool comprising:
a housing;
a brushless direct current (DC) motor within the housing, wherein the brushless DC motor includes a rotor and a stator, wherein the rotor is coupled to a motor shaft to produce a rotational output;
an impact mechanism including:
a hammer coupled to the motor shaft, and
an anvil including anvil lugs configured to receive impacts from the hammer;
an output drive device including a shaft coupled to the anvil and configured to rotate to perform a task;
a target positioned on the shaft;
a magnetic shield positioned on the shaft between the target and the anvil, and configured to magnetically isolate the anvil lugs from the target; and
a position sensor including:
an inductive sensor positioned proximate the target,
a first transmitting circuit trace, and
a first receiving circuit trace, wherein the inductive sensor is configured to inject a signal on the first transmitting circuit trace and detect a first output signal on the first receiving circuit trace to determine a position of the anvil; and
a controller coupled to the position sensor and configured to:
calculate a drive angle of the anvil caused by the impact based on the determined position of the anvil, and
control the brushless DC motor based on the drive angle of the anvil.