Working device using parallel link mechanism

1. A working device using a parallel link mechanism, the working device being configured to perform a work on a workpiece with use of end effectors,

the working device comprising:

a parallel link mechanism by which the end effectors are supported so as to be changeable in posture; and

posture-controlling actuators configured to actuate the parallel link mechanism, wherein

the parallel link mechanism includes:

a proximal-end-side link hub;

a distal-end-side link hub; and

three or more link mechanisms which are disposed between the proximal-end-side link hub and the distal-end-side link hub, and by which the distal-end-side link hub is connected to the proximal-end-side link hub so that the posture of the distal-end-side link hub relative to the proximal-end-side link hub can be changed,

each link mechanism includes:

a proximal-side end link member having one end rotatably connected to the proximal-end-side link hub;

a distal-side end link member having one end rotatably connected to the distal-end-side link hub; and

a center link member having opposite ends rotatably connected to other ends of the proximal-side and distal-side end link members, respectively,

the posture-controlling actuators are provided to two or more link mechanisms among the three or more link mechanisms, the posture-controlling actuators being configured to arbitrarily change the posture of the distal-end-side link hub relative to the proximal-end-side link hub,

the end effectors are mounted to the distal-end-side link hub and include one main end effector configured to perform a main work on the workpiece and one or a plurality of sub end effectors configured to perform an auxiliary work on the workpiece, and

switching between a state where a work is performed by the main end effector and a state where a work is performed by the one or a plurality of sub end effectors,

wherein when the main end effector performs the work on the workpiece, an axis of a distal end of the main end effector is located at a non-perpendicular angle to a central vertical axis of the workpiece and at a non-perpendicular angle to an axis of a distal end of the one or a plurality of sub end effectors.

2. The working device using the parallel link mechanism as claimed in claim 1 , wherein

the main end effector and each sub end effector are mounted to the distal-end-side link hub, such that the axis of the distal end of the main end effector intersects with an axis of a distal end of each sub end effector at an arbitrary degree angle.

3. The working device using the parallel link mechanism as claimed in claim 1 , wherein

in a case where:

a point, at which an axis of a revolute pair between the proximal-end-side link hub and each proximal-side end link member intersects with an axis of a revolute pair between the proximal-side end link member and the corresponding center link member, is referred to as a proximal-end-side spherical link center; and

a straight line that passes the proximal-end-side spherical link center and that intersects, at a right angle, with the axis of the revolute pair between the proximal-end-side link hub and the proximal-side end link member, is referred to as an axis of the proximal-end-side link hub,

each of the main end effector and the sub end effector is mounted to the distal-end-side link hub, such that an axis of a distal end of the each end effector coincides with the axis of the proximal-end-side link hub in a state where the distal-end-side link hub has a predetermined posture relative to the proximal-end-side link hub.

4. The working device using the parallel link mechanism as claimed in claim 1 , wherein

in a case where:

a point, at which an axis of a revolute pair between the distal-end-side link hub and each distal-side end link member intersects with an axis of a revolute pair between the distal-side end link member and the corresponding center link member, is referred to as a distal-end-side spherical link center; and

a straight line that passes the distal-end-side spherical link center and that intersects, at the right angle, with the axis of the revolute pair between the distal-end-side link hub and the distal-side end link member, is referred to as an axis of the distal-end-side link hub,

the axis of the distal end of the main end effector coincides with the axis of the distal-end-side link hub.

5. The working device using the parallel link mechanism as claimed in claim 1 , wherein

in a case where:

the point, at which an axis of a revolute pair between the proximal-end-side link hub and each proximal-side end link member intersects with an axis of a revolute pair between the proximal-side end link member and the corresponding center link member, is referred to as the proximal-end-side spherical link center;

a straight line that passes the proximal-end-side spherical link center and that intersects, at the right angle, with the axis of the revolute pair between the proximal-end-side link hub and the proximal-side end link member, is referred to as the axis of the proximal-end-side link hub,

a point, at which the axis of the revolute pair between the distal-end-side link hub and each distal-side end link member intersects with an axis of a revolute pair between the distal-side end link member and the corresponding center link member, is referred to as the distal-end-side spherical link center; and

the straight line that passes the distal-end-side spherical link center and that intersects, at the right angle, with the axis of the revolute pair between the distal-end-side link hub and the distal-side end link member, is referred to as an axis of the distal-end-side link hub,

a distance from the proximal-end-side spherical link center to the distal end of the sub end effector, in a state where the axis of the distal end of the sub end effector and the axis of the proximal-end-side link hub coincide with each other, is equal to or shorter than a distance from the proximal-end-side spherical link center to the distal end of the main end effector in a state where the axis of the proximal-end-side link hub and the axis of the distal-end-side link hub coincide with each other.

6. The working device using the parallel link mechanism as claimed in claim 1 , wherein

the proximal-end-side link hub is mounted to a linear motion mechanism including a linear motion actuator with one or more axes.

7. The working device using the parallel link mechanism as claimed in claim 1 , wherein

the main end effector is a welding torch, and the sub end effector is a heating device.