Screw length determination system, screw-tightening system and storage medium

Patent metadata

Field	Value
Publication number	US-11512949-B2
Application number	US-201917278667-A
Country	US
Kind code	B2
Filing date	Sep 25, 2019
Priority date	Oct 29, 2018
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A screw length determination system capable of quickly determining the length of a screw is obtained. A PLC (10) is equipped with a determination part for measuring the moving speed of a driver for tightening screws in the axial direction of the driver from an initial position until a screw contacts and is screwed into a workpiece, and determining the length of the screw on the basis of the time from the start of movement from the initial position until the moving speed changes.

First claim

What is claimed is:

1. A screw length determination system comprising:
a controller configured to
measure a moving speed of a driver in an axial direction from a predetermined position before a screw comes into contact with a fastening target until the screw comes into contact with and is screwed to the fastening target, in a case in which the driver performing a rotational movement around an axis and a reciprocating movement in the axial direction in accordance with motor control mounts the screw to the fastening target, and
determine a length of the screw on the basis of a time from a movement start of the driver from the predetermined position until the moving speed measured by the controller changes before and after contact of the screw with the fastening target.

2. The screw length determination system according to claim 1 , wherein the controller determines the length of the screw with reference to a table showing a relationship between the length of the screw and a range of the time.

3. A screw-tightening system comprising:
a rotation servo that causes a rotational movement of a driver around an axis;
a reciprocating servo that causes a reciprocating movement of the driver in an axial direction;
an optical sensor that detects a position of the driver in the axial direction; and
the screw length determination system according to claim 1 .

4. A non-transitory computer readable storage medium, storing a program for operating a computer as the screw length determination system according to claim 1 .

Assignees

• Omron Tateisi Electronics Co

Inventors

• Nishigaki Koji
• Sasaki Tatsuya
• Shibutani Takanori

Classifications

• B23P19/06 Primary

  Screw or nut setting or loosening machines · CPC title

• G01B21/02

  for measuring length, width, or thickness (G01B21/10 takes precedence) · 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

• G05B19/401

  characterised by control arrangements for measuring, e.g. calibration and initialisation, measuring workpiece for machining purposes (G05B19/19 takes precedence) · CPC title

• G05B2219/45203

  Screwing · CPC title