Robot arm mechanism

A robot arm mechanism comprising:

• a first arm link mechanism consisting of a first quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link;
• a second arm link mechanism consisting of a second quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link, said third arm link of said second arm link mechanism being fixedly connected with said third arm link of said first arm link mechanism, said second arm link mechanism is pivotably connected with said first arm link mechanism;
• a link retaining mechanism having a reference line, said link retaining mechanism pivotably retaining said first arm link mechanism and said second arm link mechanism respectively and keeping a first angle substantially equal to a second angle, said first angle being an angle formed by a line passing through said second arm link of said first arm link mechanism with said reference line, said second angle being an angle formed by a line passing through said first arm link of said second arm link mechanism with said reference line;
• a handling member for supporting and handling an object, connected with said second arm link mechanism;
• and
• a robot arm driving mechanism comprising:
• a first driving shaft operative to rotate said first arm link of said first arm link mechanism around a rotation axis in any one of two rotation directions consisting of a first rotation direction in which said first arm link of said second arm link mechanism rotates in a rotation direction opposite to said first rotation direction, and said first arm link mechanism and said second arm link mechanism are extended, and a second rotation direction in which said first arm link of said second arm link mechanism rotates in a rotation direction opposite to said second rotation direction, and said first arm link mechanism and said second arm link mechanism are contracted, whereby
• said robot arm driving mechanism is operative to rotate said first arm link of said first arm link mechanism around said rotation axis in said first rotation direction, and said fourth arm link of said first arm link mechanism around said rotation axis in any one of two directions consisting of said first rotation direction and said second rotation direction while maintaining said second angle formed to be less than 180 degrees by a line passing through said first arm link of said second arm link mechanism with said reference line less than a third angle formed by a line passing through said fourth arm link of said second arm link mechanism with said reference line in said rotation direction opposite to said first rotation direction.

A robot arm mechanism comprising:

• a first arm link mechanism consisting of a first quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link;
• a second arm link mechanism consisting of a second quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link, said second arm link mechanism is pivotably connected with said first arm link mechanism;
• and
• a link retaining mechanism having a reference line, said link retaining mechanism pivotably retaining said first arm link mechanism and said second arm link mechanism respectively and keeping a first angle substantially equal to a second angle, said first angle being an angle formed by a line passing through said second arm link of said first arm link mechanism with said reference line, said second angle being an angle formed by a line passing through said first arm link of said second arm link mechanism with said reference line;
• said link retaining mechanism comprising:
• a first joint cross linkage consisting of a third quadric crank chain including:
• a first short link, a first long link longer than said first short link of said first joint cross linkage of said link retaining mechanism, a second short link substantially equal in length to said first short link of said first joint cross linkage of said link retaining mechanism, and a second long link substantially equal in length to said first long link of said first joint cross linkage of said link retaining mechanism, and crossed with said first long link of said first joint cross linkage of said link retaining mechanism, one of said first short link and said second short link of said first joint cross linkage of said link retaining mechanism fixedly connected with one of said first arm link and said second arm link of said first arm link mechanism and said first arm link and said second arm link of said second arm link mechanism and one of said first long link and said second long link of said first joint cross linkage of said link retaining mechanism fixedly connected with one of said third arm link and said fourth arm link of said first arm link mechanism,
• a second joint cross linkage consisting of a fourth quadric crank chain including:
• a first short link, a first long link longer than said first short link of said second joint cross linkage of said link retaining mechanism, a second short link substantially equal in length to said first short link of said second joint cross linkage of said link retaining mechanism, and a second long link substantially equal in length to said first long link of said second joint cross linkage of said link retaining mechanism, and crossed with said first long link of said second joint cross linkage of said link retaining mechanism, one of said first short link and said second short link of said second joint cross linkage of said link retaining mechanism fixedly connected with one of said first long link and said second long link of said first joint cross linkage of said link retaining mechanism, one of said first long link and said second long link of said second joint cross linkage of said link retaining mechanism fixedly connected with one of the remaining ones of said first arm link and said second arm link of said first arm link mechanism and said first arm link and said second arm link of said second arm link mechanism, and the other one of said first long link and said second long link of said second joint cross linkage of said link retaining mechanism fixedly connected with one of the remaining ones of said first short link and said second short link of said first joint cross linkage of said link retaining mechanism,
• a handling member for supporting and handling an object, connected with said second arm link mechanism, and
• a robot arm driving mechanism comprising:
• a first driving shaft operative to rotate said first arm link of said first arm link mechanism around a rotation axis in any one of two rotation directions consisting of a first rotation direction in which said first arm link of said second arm link mechanism rotates in a rotation direction opposite to said first rotation direction, and said first arm link mechanism and said second arm link mechanism are extended, and a second rotation direction in which said first arm link of said second arm link mechanism rotates in a rotation direction opposite to said second rotation direction, and said first arm link mechanism and said second arm link mechanism are contracted, whereby
• said link retaining mechanism is operative to keep a line passing through said one of said first short link and said second short link of said first joint cross linkage of said link retaining mechanism forward in a rotation direction, in which said first arm link mechanism and said second arm link mechanism are contracted, with respect to a line passing through said one of said first long link and said second long link of said first joint cross linkage of said link retaining mechanism in comparison with a line passing through said one of said first short link and said second short link of said first joint cross linkage of said link retaining mechanism expected to be placed with respect to a line passing through said one of said first long link and said second long link of said first joint cross linkage of said link retaining mechanism when said one of said first short link and said second short link of said first joint cross linkage of said link retaining mechanism and said one of said first long link and said second long link of said second joint cross linkage of said link retaining mechanism are respectively placed in substantially collinear relationship with said one of said first arm link and said second arm link of said first arm link mechanism and said first arm link and said second arm link of said second arm link mechanism and said one of the remaining ones of said first arm link and said second arm link of said first arm link mechanism and said first arm link and said second arm link of said second arm link mechanism.

A robot arm mechanism comprising:

• a first arm link mechanism consisting of a first quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link;
• a second arm link mechanism consisting of a second quadric crank chain comprising a first arm link, a second arm link substantially in parallel relationship with said first arm link, a third arm link, and a fourth arm link substantially in parallel relationship with said third arm link, said third arm link of said second arm link mechanism being fixedly connected with said third arm link of said first arm link mechanism, said second arm link mechanism is pivotably connected with said first arm link mechanism;
• a link retaining mechanism having a reference line, said link retaining mechanism pivotably retaining said first arm link mechanism and said second arm link mechanism respectively and keeping a first angle substantially equal to a second angle, said first angle being an angle formed by a line passing through said first arm link of said first arm link mechanism with said reference line, said second angle being an angle formed by a line passing through said first arm link of said second arm link mechanism with said reference line;
• and
• a robot arm driving mechanism comprising;
• a first driving shaft operative to rotate said first arm link of said first arm link mechanism around a rotation axis in any one of two rotation directions consisting of a first rotation direction in which said first arm link mechanism and said second arm link mechanism are extended, and a second rotation direction in which said first arm link mechanism and said second arm link mechanism are contracted, whereby
• said robot arm driving mechanism is operative to rotate said first arm link of said first arm link mechanism around said rotation axis in said first rotation direction, and said fourth arm link of said first arm link mechanism around said rotation axis in any one of two directions consisting of said first rotation direction and said second rotation direction while maintaining said first angle formed by a line passing through said first arm link of said first arm link mechanism with said reference line less than a third angle formed to be less than 180 degrees by a line passing through said fourth arm link of said first arm link mechanism with said reference line in said first rotation direction as well as maintaining said second angle formed by a line passing through said first arm link of said second arm link mechanism with said reference line less than a fourth angle formed to be less than 180 degrees by a line passing through said fourth arm link of said second arm link mechanism with said reference line in said rotation direction opposite to said first rotation direction.