Impact tool with control mode

Patent metadata

Field	Value
Publication number	US-11904441-B2
Application number	US-201916523734-A
Country	US
Kind code	B2
Filing date	Jul 26, 2019
Priority date	Feb 27, 2015
Publication date	Feb 20, 2024
Grant date	Feb 20, 2024

Abstract

An impact tool includes a controller configured to control power being delivered to the and operable in one of: (a) a normal mode where the controller allows power to be delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a normal transition torque; and (b) a control mode where the controller controls power being delivered to the motor so that the impact mechanism transitions from operation in the rotary mode to operation in the impacting mode when an output torque exceeds a control transition torque that is greater than the normal transition torque.

First claim

What is claimed is:

1. 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 transmit continuous rotary motion without impacts from the motor to the output spindle when a torque on the output spindle does not exceed a transition torque, and to transmit rotational impacts from the motor to the output spindle when a torque on the output spindle exceeds the transition torque while the motor rotates in a single direction; and
a controller electrically coupled to the motor and configured to electrically control power being delivered to the motor wherein the controller is selectively operable in: (a) a normal mode where the controller controls power being delivered to the motor so that the impact mechanism transitions from transmitting continuous rotary motion to transmitting rotational impacts when the transition torque is a first threshold torque; and (b) a control mode where the controller temporarily holds power being delivered to the motor at or below a first power limit, and then allows power delivered to the motor to increase beyond the first power limit, so that the impact mechanism transitions from transmitting continuous rotary motion to transmitting rotational impacts when the transition torque is a second threshold torque that is greater than the first threshold torque.

2. The impact tool of claim 1 , wherein the controller temporarily limits power being delivered to the motor by limiting a parameter or analogue of power.

3. The impact tool of claim 1 , wherein, the first power limit corresponds to a first output torque that is lower than the first threshold torque.

4. The impact tool of claim 3 , wherein, in the control mode, the controller limits power delivered to the motor to not exceed the first power limit until a first predetermined time period after the controller determines that a tool parameter has reached a first threshold.

5. The impact tool of claim 4 , wherein the tool parameter reaching the first threshold corresponds to at least one of an output torque reaching a first torque limit, a motor speed decreasing to reach a speed threshold, and a current reaching a first current threshold.

6. The impact tool of claim 4 , wherein, in the control mode, the controller subsequently limits power being delivered to the motor to not exceed a second power limit until a second predetermined time period after the controller determines that the tool parameter has reached a second threshold.

7. The impact tool of claim 6 , wherein the second power limit corresponds to a second output torque that is higher than the first output torque.

8. The impact tool of claim 7 , wherein the second output torque is greater than the first threshold torque.

9. The impact tool of claim 6 , wherein, in the control mode, the controller subsequently allows power being delivered to the motor to exceed a control transition power that is higher than a power that corresponds to the first threshold torque, the control transition power corresponding to the second threshold torque.

10. The impact tool of claim 1 , wherein, in the control mode, the controller: (a) sets a plurality of intermediate power limits, each corresponding to a torque that is less than the control transition torque, for a plurality of time periods; and (b) limits the power delivered to the motor not to exceed the power limit when that power limit is set, wherein at least one of the plurality of power limits corresponds to an output torque that is lower than the first threshold torque.

11. The impact tool of claim 10 , wherein the plurality of intermediate power limits sequentially increase.

12. The impact tool of claim 1 , wherein, in the control mode, after the impact mechanism transitions to transmitting rotational impacts to the output spindle, the controller sets an impacting power limit that is lower than the power at which the impact mechanism transitions to transmitting rotational impacts to the output spindle.

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.

14. The impact tool of claim 13 , wherein, at each at least one intermediate power limit, the controller is configured to limit power delivered to the motor not to exceed that intermediate power limit for a time period.

15. The impact tool of claim 14 , wherein each time period is a predetermined time period after a tool parameter has been reached.

16. The impact tool of claim 15 , wherein the tool parameter comprises at least one of a motor speed, an output torque, a power delivered to the motor, a current delivered to the motor, a voltage delivered to the motor, and a duty cycle of a signal applied to the motor.

17. The impact tool of claim 14 , wherein the at least one intermediate power limit comprises a plurality of intermediate power limits, with each intermediate time limit corresponding to a predetermined time period, wherein the predetermined time period that corresponds to a highest intermediate power limit of the intermediate power limits is a longest time period of the predetermined time periods.

18. The impact tool of claim 17 , wherein after the predetermined time period corresponding to the highest intermediate power limit has expired, the controller is configured to allow an amount of power delivered to the motor to exceed a transition power that corresponds to the second transition torque.

19. The impact tool of claim 17 , wherein at least the highest intermediate power limit corresponds to an output torque that is greater than the first transition torque.

Assignees

• Black & Decker Inc

Inventors

• Leh Jason K
• NAJJAR Karim
• Rudolph Scott M
• White Daniel

Classifications

• B25B23/1475 Primary

  for impact wrenches or screwdrivers · CPC title

• B25B21/02

  with means for imparting impact to screwdriver blade or nut socket · CPC title