Conveyor system

A carrying device comprising:

• a support member;
• first and second shafts coaxially supported on the support member;
• a frog leg type arm having a base end part connected to the first and the second shaft;
• and
• a holding member for holding a workpiece, connected to a front end part of the frog leg type arm;
• wherein the frog leg type arm comprises:
• a rotatable first drive arm having a base end part mounted on the first shaft,
• a rotatable second drive arm having a base end part mounted on the second shaft,
• a front arm having a base end part pivotally connected by a first joint to a front end part of the first drive arm and
• two links extended in parallel to the first drive arm and having opposite end parts connected to the front arm and the second drive arm;
• the first and the second drive arm, the front arm and the two links have the same length, and the first and the second drive arm, the front arm and the two links form two parallel linkages;
• the two parallel linkages have different uncontrollable and unstable points, respectively, and the first and the second drive arm and the front arm form three sides of a rhombus;
• the holding member is pivotally connected to a front end part of the front arm by a second joint;
• and
• the front arm, a front end part of the second drive arm and the holding member are linked by a posture maintaining linkage having two similar antiparallel linkages, and the posture maintaining linkage controls the turning of the holding member relative to the front arm.

A carrying device comprising:

• a support member;
• a parallel linkage type arm having a base end part supported on the support member;
• and
• a holding member for holding a workpiece, connected to a front end part of the parallel linkage type arm;
• wherein the parallel linkage type arm comprises:
• a first link fixed to the support member,
• a rotatable drive arm having a base end part mounted on a drive shaft penetrating an end part of the first link,
• a driven arm having a base end part pivotally connected to the other end of the first link by a first joint,
• a second link pivotally connected to front end parts of the drive arm and the driven arm by second and third joints, respectively, and
• first and second front arms having base end parts pivotally connected to the second link;
• the holding member is connected pivotally to front end parts of the first and the second front arm by fourth and fifth joints;
• and
• the drive arm or the driven arm, the second link, and the first or the second front arm are linked by a posture maintaining linkage having two similar antiparallel linkages, and the posture maintaining linkage makes the holding member move along a straight line.