Method and system for quickly and efficiently transferring a workpiece from a first station to a second station

A method for quickly and efficiently transferring a workpiece from a first work station to a second work station having a distance therebetween, the method comprising the steps of:

• providing a support structure;
• providing a robot including an arm assembly rotatable about first, second and third axes, the second axis being substantially orthogonal to the first axis and the third axis being substantially orthogonal to the second axis, the robot being supported on the support structure so that the arm assembly is located at a position above and between the first and second work stations, and so that the arm assembly is capable of swinging between the first work station and the second work station about and below the first axis;
• providing an end effector on the arm assembly;
• swinging the arm assembly about the first axis to the first work station;
• utilizing the end effector to pick up the workpiece at the first work station;
• swinging the arm assembly from the first work station to the second work station such that the force of gravity accelerates the arm assembly within a first half of the distance between the first and second work stations and decelerates the arm assembly within a second half of the distance, thereby allowing a quick and efficient transfer of the workpiece between the first and second work stations;
• rotating the arm assembly about the second and third axes during the step of swinging the arm assembly from the first work station to the second work station to allow a center of gravity of the workpiece to follow a substantially straight line path between the first and second work stations wherein the second axis intersects the first axis when the arm assembly is located substantially one-half of the distance between the first and second work stations;
• and
• utilizing the end effector to place the workpiece at the second work station.

A system for quickly and efficiently transferring a workpiece from a first work station to a second work station along a straight line flow path, the system comprising:

• a support structure;
• a robot supported on the support structure and including an arm assembly having a first and second linkages, the first linkage being pivotally supported proximal the first end of the arm assembly to swing about and below a first axis adapted to be located above and between the first and second work stations, and the second linkage being supported on the first linkage to rotate about second and third axes, the arm assembly being capable of swinging between the first work station and the second work station about the first axis wherein gravitational force is utilized to at least partially drive the first linkage between the first work station and the second work station in a plane that is offset from and parallel to the flow path wherein the second axis intersects the first axis when the first linkage is substantially midway along the flow path;
• and
• an end effector supported on a second end of the arm assembly distal the first axis and adapted to pick up the workpiece at the first work station and adapted to place the workpiece at the second work station.

A system for quickly and efficiently transferring a workpiece from a first work station to a second work station, the system comprising:

• a support structure;
• a robot supported on the support structure and including an arm assembly pivotally supported proximal the first end of the arm assembly to swing about and below a first axis adapted to be located above and between the first and second work stations, the arm assembly including two independently actuated linkages which are relatively rotatable about second and third axes and which are adapted to swing between the first work station and the second work station about the first axis wherein gravitational force is utilized to at least partially drive the workpiece between the first work station and the second work station wherein movement of one of the linkages relative to the other linkage about the third axis is adapted to compensate for any height difference between the first and second work stations so that the workpiece follows a path that approximates a straight line between the first and second work stations and wherein the second axis intersects the first axis when the arm assembly is substantially midway along the path;
• and
• an end effector supported on a second end of the arm assembly distal the first axis and adapted to pick up the workpiece at the first work station and adapted to place the workpiece at the second work station.

A system for quickly and efficiently transferring a workpiece from a first work station to a second work station along a substantially horizontal flow path, the system comprising:

• an elevated support structure offset horizontally from the flow path;
• a robot including a first four bar linkage having a base link mounted on the support structure in a substantially vertical position, said vertical position being locatable above and between the first and second work stations, a first transport link substantially equal in length to the length of the base link, and two control links of substantially equal lengths pivotally connected to the base link and the first transport link to swing below the base link about a set of substantially horizontal axes including a first axis located at the base link in a vertical plane locatable so as to intersect the flow path proximal a middle point between the first and second work stations, a platform link pivotally connected to the first transport link to rotate about a substantially vertical second axis, a second transport link, and two height compensating links pivotally connected to both the platform link and the second transport link to form a second four bar linkage having a set of parallel pivotal axes including a third axis which lies in a plane which is substantially horizontal and orthogonal to the second axis;
• and
• an end effector mounted on the second transport link and adapted to pick up the workpiece at the first work station and adapted to place the workpiece at the second work station.

A system for quickly and efficiently transferring a workpiece from a first work station to a second work station along a substantially horizontal flow path intersecting a median plane orthogonally proximal a middle point of the flow path, the system comprising:

• an elevated support structure offset horizontally in the medial plane from the flow path;
• a robot including a base link mounted on the support structure in a substantially vertical position, said vertical position being locatable above and between the first and second work stations, a first transport link connected to the base link by means of two first control links to form a first parallel four bar mechanism having a first set of substantially horizontal pivotal axes adapted to be located between the first and second work stations, a second transport link, a platform link pivotally connected to the first transport link about a substantially vertical second axis and connected to the second transport link by means of two second control links to form a second parallel four bar mechanism having a second set of substantially horizontal pivotal axes, said base link being substantially parallel to the flow path;
• and
• an end effector mounted on the second transport link and adapted to pick up the workpiece at the first work station and adapted to place the workpiece at the second work station.

A method for quickly and efficiently transferring a workpiece from a first work station to a second work station having a generally horizontal transfer path therebetween, the method comprising the steps of:

• providing an elevated support structure at a location offset perpendicularly and horizontally from the transfer path and between the first and second work stations;
• providing a robot having links independently rotatable about first, second, and third axes by means of first, second, and third axis actuators, respectively;
• the first axis being substantially horizontal and substantially perpendicular to the transfer path, and adapted to be located above and between the first and second work stations;
• the second axis being substantially vertical and rotatable about the first axis;
• and the third axis being substantially horizontal and rotatable about the second axis, hence, providing the robot with three generally independent degrees of freedom;
• the robot being pivotally supported on the elevated support structure to swing about and below the first axis so as to reciprocate between the first and the second work stations;
• providing the robot with an end effector;
• rotating the robot about the first axis under power of the first axis actuator to move the robot to the first work station thereby initiating a workpiece transfer cycle;
• stopping the robot momentarily at the first work station;
• utilizing the end effector to pick up the workpiece at the first work station;
• and
• swinging the robot from the first work station to the second work station so that the force of gravity accelerates the robot within a first half of the distance between the first and second work stations and decelerates the robot within a second half of the distance, thereby minimizing the energy spent by the first axis actuator and allowing quick and efficient transfer of the workpiece between the first and second work stations;
• stopping the robot momentarily at the second work station;
• utilizing the end effector to place the workpiece at the second work station;
• swinging the robot from the second work station to the first work station thus allowing the robot to begin a new transfer cycle.