Threaded member tightening tool and drive time setting method for threaded member tightening tool

Patent metadata

Field	Value
Publication number	US-2018281160-A1
Application number	US-201816002484-A
Country	US
Kind code	A1
Filing date	Jun 7, 2018
Priority date	Dec 25, 2015
Publication date	Oct 4, 2018
Grant date	—

Abstract

A threaded member tightening tool for setting the length of drive time to elapse before rotation is switched from high-speed rotation to low-speed rotation. A motor-driven screwdriver system in which a screwdriver bit is first driven at a predetermined high rotational speed only for a high-speed drive time and thereafter driven at a predetermined low rotational speed lower than the high rotational speed. A control unit drive-controls an electric motor so that the screwdriver bit is rotationally driven at a setting rotational speed, measures a tightening time required until a Hall element detects that a threaded member engaged with the screwdriver bit has been tightened completely, calculates an initial setting time by multiplying the tightening time by a predetermined positive value less than 1 and a value obtained by dividing the setting rotational speed by the high rotational speed, and sets the high-speed drive time to the initial setting time.

First claim

1 . A threaded member tightening tool comprising:
an electric motor for rotationally driving a threaded member engaging unit engageable with a threaded member; a control unit drive-controlling the electric motor; and a tightening detecting unit detecting that a threaded member has been tightened to an object to be fastened; the control unit being configured to control the electric motor so that the threaded member engaging unit is first rotationally driven at a predetermined high rotational speed only for a high-speed drive time and thereafter rotationally driven at a predetermined low rotational speed lower than the high rotational speed; wherein the control unit drive-controls the electric motor so that the threaded member engaging unit is rotationally driven at a setting rotational speed, measures a tightening time required until the tightening detecting unit detects that a threaded member engaged with the threaded member engaging unit has been tightened to an object to be fastened, calculates an initial setting time by multiplying the tightening time by a predetermined positive value less than 1 and a value obtained by dividing the setting rotational speed by the high rotational speed, and sets the high-speed drive time to the initial setting time.

2 . The threaded member tightening tool of claim 1 , further comprising:
an operation input device transmitting a setting time changing signal to the control unit; the control unit being configured to calculate, when receiving the setting time changing signal, a first resetting time by adding or subtracting a predetermined adjusting time to or from the high-speed drive time, and to reset the high-speed drive time to the first resetting time.

3 . The threaded member tightening tool of claim 1 , further comprising:
an operation input device transmitting a setting time changing signal to the control unit; the control unit being configured to calculate, when receiving the setting time changing signal, a first resetting time by increasing or decreasing the high-speed drive time by an amount corresponding to a predetermined proportion of the high-speed drive time, and to reset the high-speed drive time to the first resetting time.

4 . The threaded member tightening tool of claim 1 , wherein the control unit measures a low-speed drive time required from when the high-speed drive time has elapsed until the tightening detecting unit detects that a threaded member has been tightened to an object to be fastened, calculates a first resetting time by adding or subtracting an adjusting time to or from the high-speed drive time, the adjusting time being obtained by multiplying the low-speed drive time by a predetermined positive value less than 1 and a value obtained by dividing the low rotational speed by the high rotational speed, and resets the high-speed drive time to the first resetting time.

5 . The threaded member tightening tool of claim 1 , wherein the control unit calculates a second resetting time by subtracting a predetermined adjusting time from the high-speed drive time when the tightening detecting unit detects that a threaded member has been tightened to an object to be fastened before the high-speed drive time has elapsed, and resets the high-speed drive time to the second resetting time.

6 . The threaded member tightening tool of claim 1 , wherein when the tightening detecting unit detects that a threaded member has been tightened to an object to be fastened before the high-speed drive time has elapsed, the control unit calculates a second resetting time by multiplying the high-speed drive time by a predetermined positive value less than 1, and resets the high-speed drive time to the second resetting time.

7 . A drive time setting method of setting a high-speed drive time for a threaded member tightening tool, the threaded member tightening tool having an electric motor for rotationally driving a threaded member engaging unit engageable with a threaded member, and a control unit drive-controlling the electric motor, the control unit being configured to control the electric motor so that the threaded member engaging unit is first rotationally driven at a predetermined high rotational speed only for a high-speed drive time and thereafter rotationally driven at a predetermined low rotational speed lower than the high rotational speed;
the drive time setting method comprising: the step of rotationally driving the threaded member engaging unit at a setting rotational speed and of measuring a tightening time required until a threaded member engaged with the threaded member engaging unit has been tightened to an object to be fastened; the step of calculating an initial setting time by multiplying the tightening time by a predetermined positive value less than 1 and a value obtained by dividing the setting rotational speed by the high rotational speed; and the step of setting the high-speed drive time to the initial setting time.

8 . The drive time setting method of claim 7 , further comprising, following the step of setting the high-speed drive time to the initial setting time:
the step of calculating a first resetting time by adding or subtracting a predetermined adjusting time to or from the high-speed drive time; and the step of resetting the high-speed drive time to the first resetting time.

9 . The drive time setting method of claim 7 , further comprising, following the step of setting the high-speed drive time to the initial setting time:
the step of calculating a first resetting time by increasing or decreasing the high-speed drive time by an amount corresponding to a predetermined proportion of the high-speed drive time; and the step of resetting the high-speed drive time to the first resetting time.

10 . The drive time setting method of claim 7 , further comprising, following the step of setting the high-speed drive time to the initial setting time:
the step of, while performing a threaded member tightening operation with the threaded member tightening tool, measuring a low-speed drive time required from when the high-speed drive time has elapsed until a threaded member has been tightened to an object to be fastened; the step of calculating a first resetting time by adding or subtracting an adjusting time to or from the high-speed drive time, the adjusting time being obtained by multiplying the low-speed drive time by a predetermined positive value less than 1 and a value obtained by dividing the low rotational speed by the high rotational speed; and the step of resetting the high-speed drive time to the first resetting time.

11 . The drive time setting method of claim 7 , further comprising:
the step of, when a threaded member has been tightened to an object to be fastened before the high-speed drive time has elapsed during a threaded member tightening operation performed with the threaded member tightening tool, calculating a second resetting time by subtracting a predetermined adjusting time from the high-speed drive time; and the step of resetting the high-speed drive time to the second resetting time.

12 . The drive time setting method of claim 7 , further comprising:
the step of, when a threaded member has been tightened to an object to be fastened before the high-speed drive time has elapsed during a threaded member tightening operation performed with the threaded member tightening tool, calculating a second resetting time by multiplying the high-speed drive time by a predetermined positive value less than 1; and the step of resetting the high-speed drive time to the second resetting time.

Assignees

• Nitto Kohki Co

Inventors

• Uemura Koya

Classifications

• B25B23/147 Primary

  specially adapted for electrically operated wrenches or screwdrivers · CPC title

• B25B21/008

  with automatic change-over from high speed-low torque mode to low speed-high torque mode · CPC title

• B23P19/06

  Screw or nut setting or loosening machines · CPC title

• B25B23/14

  Arrangement of torque limiters or torque indicators in wrenches or screwdrivers (couplings for transmitting rotation or clutches F16D; devices for measuring torque per se G01L) · CPC title