Patent ID: 11904441
Assignee: BLACK & DECKER, INC.
Field: Machine tools (Mechanical engineering)
Classification: CPC B | IPC B

Claim 12:
13. An impact tool comprising:
a housing;
a motor disposed in the housing;
an output spindle;
an impact mechanism coupled to the output spindle and configured to be driven by the motor, the impact mechanism configured to operate in one of a rotary mode in which the impact mechanism transmits rotational motion to the output spindle without impacts and an impacting mode in which the impact mechanism transmits rotational impacts to the output spindle, wherein, absent any limit on power delivered to the motor, the impact mechanism is configured to transition from operating in the rotary mode to operating in the impacting mode when a torque on the output spindle exceeds a first transition torque; and
a controller electrically coupled to the motor and configured to electrically control power being delivered to the motor so that the impact mechanism transitions from operating in the rotary mode to operating in the impacting mode when a torque on the output spindle exceeds a second transition torque that is higher than the first transition torque by: (a) setting at least one intermediate power limit corresponding to a torque that is less than the control transition torque for at least one time period; and (b) temporarily holding power delivered to the motor at or below each of the at least one intermediate power limit when that intermediate power limit is set and then allowing power delivered to the motor to exceed each of the at least one intermediate power limit, wherein each of the at least one intermediate power limits corresponds to an output torque that is lower than the first transition torque.