Bolt tightening method, bolt tightening device, bolt supplying method, and bolt supplying device

A device of tightening bolts comprising:

• a tightening head on which a nut runner is mounted;
• an attaching and detaching mechanism for detachably connecting a socket portion with an output shaft of the nut runner;
• a posture changing mechanism for changing a posture of the socket portion, which has been disconnected from the output shaft of the nut runner, between an upward posture in which a bolt holding portion provided at a forward end of the socket portion directs upward and a tightening posture in which the socket portion is laid along an axis of the output shaft of the nut runner;
• and
• a bolt supplying mechanism having a bolt magazine for holding a plurality of bolts and also having a bolt grasping mechanism for grasping one bolt held by the bolt magazine and for inserting the bolt from an upper side into the bolt holding portion of the socket portion at the upward posture.

A method of tightening bolts for tightening a plurality of bolts to a work by using at least two sockets which are alternatively connected to an output shaft of a nut runner, the method comprising:

• a bolt supplying preparing step including:
• releasing a socket connected to the output shaft of the nut runner from the output shaft of the nut runner;
• moving the socket to a waiting position apart from an axis of the output shaft of the nut runner and
• changing a posture of the socket to an upward posture in which a bolt holding portion of a forward end of the socket directs upward;
• a bolt tightening preparing step including:
• moving the socket to a using position agreeing with the axis of the output shaft of the nut runner;
• changing the posture of the socket to a tightening posture in which the socket is laid along the axis;
• and
• connecting the socket to the output shaft of the nut runner;
• and
• simultaneously executing the bolt supplying preparing step for one socket and the bolt tightening preparing step for another socket.

A device of tightening bolts comprising:

• a nut runner;
• a least two sockets alternatively connected to an output shaft of the nut runner;
• a socket replacing mechanism for moving each socket to a using position at which the socket agrees with an axis of the output shaft of the nut runner, and for moving each socket to a waiting position which is apart from the axis, for changing a posture of each socket to an upward posture in which a bolt holding portion of a forward end of the socket directs upward when the socket is moved to the waiting position, and for changing a posture of each socket to a tightening posture in which the socket is laid along the axis of the output shaft of the nut runner when the socket is moved to the using position;
• and
• an attaching and detaching mechanism for detachably connecting the socket at the using position with the output shaft of the nut runner,
• wherein the socket replacing mechanism simultaneously moves one socket to the waiting position and the other socket to the using position.

A method of supplying a bolt to a socket provided in a bolt tightening device, the method comprising:

• a bolt supplying preparing step of changing a posture of the socket from a predetermined tightening posture to an upward posture in which a bolt holding portion provided at a forward end of the socket directs upward;
• and
• a bolt supplying step of grasping one of a plurality of bolts held by a bolt magazine arranged at a position higher than the bolt holding portion of the socket in the upward posture, and inserting the bolt into the bolt holding portion of the socket,
• wherein the bolt supplying step includes:
• a bolt holding preparing step of moving the bolt magazine to a bolt delivering position where one of the plurality of bolts held by the magazine can be grasped by the bolt grasping mechanism;
• a bolt grasping step of grasping the bolt by the bolt grasping mechanism;
• a magazine withdrawal step of moving the bolt magazine to a withdrawal position apart from a downward moving locus of the bolt grasping mechanism;
• and
• a bolt insertion step of moving the bolt grasping mechanism downward and inserting the bolt from an upper side into the bolt holding portion of the socket in the upward posture, after a completion of the bolt supplying preparing step.

A bolt supplying device for supplying a bolt to a socket provided in a bolt tightening device in which a posture of the socket is changeable from a predetermined tightening posture to an upward posture in which a bolt holding portion on a forward end of the socket is directs, the device comprising:

• a bolt magazine configured to hold a plurality of bolts therein and arranged at a position higher than the bolt holding portion of the socket in the upward posture;
• and
• a bolt grasping mechanism for grasping one of the bolts held by the bolt magazine and inserting the bolt from an upper side into the bolt holding portion of the socket in the upward posture,
• wherein the bolt grasping mechanism is linearly movable in a vertical direction on an axis of the socket in the upward posture, and
• wherein the bolt magazine is movable between a bolt delivering position at which one of the bolts held by the magazine is grasped by the bolt grasping mechanism and a withdrawal position which is apart from a downward moving locus of the bolt grasping mechanism.