Rebar tying tool and electric work machine

Patent metadata

Field	Value
Publication number	US-11554409-B2
Application number	US-202017115023-A
Country	US
Kind code	B2
Filing date	Dec 8, 2020
Priority date	Dec 17, 2019
Publication date	Jan 17, 2023
Grant date	Jan 17, 2023

Abstract

A rebar tying tool ( 2; 302; 402 ) include a feed mechanism ( 24 ), which includes a first motor ( 32; 304 ) and feeds a wire (W), and a twisting mechanism, which includes a second motor ( 76; 306 ) and twists together one or more portions of the wire. A control unit ( 202; 350 ) controls the first motor and the second motor and includes a general-purpose I/O port ( 202 c; 350 c ) and a motor-control-signal output port ( 202 a; 350 a ). A motor-control-signal-output-destination-switching circuit ( 204; 310; 406 ) inputs motor-control signals (UH, VH, WH, UL, VL, WL) from the control unit via the motor-control-signal output port and selectively outputs the inputted motor-control signals to either the first motor or the second motor in response to input of a switching signal (SW).

First claim

We claim:

1. A rebar tying tool comprising:
a feed mechanism configured to feed a wire and including a first motor having a first rotor;
a twisting mechanism configured to twist together ends of the wire and including a second motor having a second rotor;
a control unit configured to control the first motor and the second motor;
a first brake circuit configured to output a short-circuit brake signal to the first motor; and
a motor-control-signal-output-destination-switching circuit;
wherein:
the control unit comprises a motor-control-signal output port;
the motor-control-signal-output-destination-switching circuit is configured to selectively output motor-control signals from the motor-control-signal output port of the control unit to either the first motor or the second motor;
the motor-control-signal-output-destination-switching circuit is configured to select one of the first motor or the second motor to be driven with the motor-control signals in response to input of an output-switching signal; and
the control unit is configured to cause the first brake circuit to output the short-circuit brake signal from the first brake circuit to the first motor either when or before the motor-control-signal-output-destination-switching circuit switches from a first state in which the first motor is selected to be driven with the motor-control signals to a second state in which the second motor is selected to be driven with the motor-control signals.

2. The rebar tying tool according to claim 1 , wherein:
the control unit is configured to output the output-switching signal from a first general-purpose I/O port of the control unit; and
the motor-control-signal output port is configured to perform signal processing faster than the first general-purpose I/O port.

3. The rebar tying tool according to claim 1 , wherein the motor-control-signal-output-destination-switching circuit comprises a demultiplexer.

4. The rebar tying tool according to claim 1 , wherein the control unit is configured to energize the second motor to start rotation of the second rotor (i) in response to the motor-control-signal-output-destination-switching circuit switching from the first state to the second state and (ii) before rotation of the first rotor of the first motor has completely stopped.

5. The rebar tying tool according to claim 1 , wherein the control unit is configured to cause the first brake circuit to output the short-circuit brake signal from the first brake circuit to the first motor before the motor-control-signal-output-destination-switching circuit switches from the first state to the second state.

6. The rebar tying tool according to claim 1 , wherein the control unit is configured to output a short-circuit brake signal to the first motor via the motor-control-signal-output-destination-switching circuit before causing the first brake circuit to output the short-circuit brake signal to the first motor.

7. The rebar tying tool according to claim 1 , further comprising:
a second brake circuit configured to output a short-circuit brake signal to the second motor;
wherein the control unit is configured to cause the second brake circuit to output the short-circuit brake signal from the second brake circuit to the second motor either when or before the motor-control-signal-output-destination-switching circuit switches from the second state to the first state.

8. The rebar tying tool according to claim 7 , wherein the control unit is configured to energize the first motor to start rotation of the first rotor (i) in response to the motor-control-signal-output-destination-switching circuit switching from the second state to the first state and (ii) before rotation of the second rotor of the second motor has completely stopped.

9. The rebar tying tool according to claim 7 , wherein the control unit is configured to cause the second brake circuit to output the short-circuit brake signal from the second brake circuit to the second motor before the motor-control-signal-output-destination-switching circuit switches from the second state to the first state.

10. The rebar tying tool according to claim 7 , wherein the control unit is configured to output a short-circuit brake signal to the second motor via the motor-control-signal-output-destination-switching circuit before causing the second brake circuit to output the short-circuit brake signal to the second motor.

11. The rebar tying tool according to claim 1 , wherein the first motor is a brushless motor.

12. The rebar tying tool according to claim 1 , wherein the second motor is a brushless motor.

13. The rebar tying tool according to claim 10 , wherein:
the control unit is configured to output the output-switching signal from a first general-purpose I/O port of the control unit;
the motor-control-signal output port is configured to perform signal processing faster than the first general-purpose I/O port;
the motor-control-signal-output-destination-switching circuit comprises a demultiplexer; and
the control unit is configured to:
energize the second motor to start rotation of the second rotor (i) in response to the motor-control-signal-output-destination-switching circuit switching from the first state to the second state and (ii) before rotation of the first rotor of the first motor has completely stopped;
cause the first brake circuit to output the short-circuit brake signal from the first brake circuit to the first motor before the motor-control-signal-output-destination-switching circuit switches from the first state to the second state;
output a short-circuit brake signal to the first motor via the motor-control-signal-output-destination-switching circuit before causing the first brake circuit to output the short-circuit brake signal to the first motor;
energize the first motor to start rotation of the first rotor (i) in response to the motor-control-signal-output-destination-switching circuit switching from the second state to the first state and (ii) before rotation of the second rotor of the second motor has completely stopped; and
cause the second brake circuit to output the short-circuit brake signal from the second brake circuit to the second motor before the motor-control-signal-output-destination-switching circuit switches from the second state to the first state.

14. The rebar tying tool according to claim 13 , further comprising:
a motor-rotation-signal-input-source-switching circuit that comprises a multiplexer;
wherein:
the first motor is a first brushless motor;
the second motor is a second brushless motor;
the first brushless motor comprises a first Hall-effect sensor;
the second brushless motor comprises a second Hall-effect sensor;
the control unit further comprises a motor-rotation-signal input port;
the motor-rotation-signal-input-source-switching circuit is configured to input one set of signals selected from first Hall-effect sensor signals from the first Hall-effect sensor and second Hall-effect sensor signals from the second Hall-effect sensor to the motor-rotation-signal input port;
the motor-rotation-signal-input-source-switching circuit is configured to select the one set of signals to be input the motor-rotation-signal input port in response to input of an input-switching signal to the motor-rotation-signal-input-source-switching circuit;
the input-switching signal is output from the first general-purpose I/O port of the control unit;
the first Hall-effect sensor signals are also input to a second general-purpose I/O port of the control unit; and
the second Hall-effect sensor signals are also input to a third general-purpose I/O port of the cont

Assignees

• Makita Corp

Inventors

• Mizuno Shunta
• Watanabe Masahiro
• Kawai Yuki

Classifications

• E04C5/162

  Connectors or means for connecting parts for reinforcements (E04C5/168 takes precedence) · CPC title

• B21F15/04 Primary

  without additional connecting elements or material, e.g. by twisting · CPC title

• E04G21/123

  Wire twisting tools (bundling articles by twisting, e.g. wire B65B13/28; bundling rods, sticks, or like elongated objects with, e.g. wire B65B27/10; tying devices for hops, vines or trees with, e.g. wire A01G17/08) · CPC title

• B21F15/06 Primary

  with additional connecting elements or material · CPC title