Gear unit for a manipulator

#My present invention relates to a gear unit for a manipulator, e.g. an arm of an industrial robot.

#A gear unit for a manipulator can comprise three segments mounted following each other and pivotable together with respect to each other about first and second inclined pivot axes with three drive shafts mounted concentric to each other, of which intermediate drive shafts are journaled along the first and second inclined pivot axes and which can have reduction gears associated with their output or driven side. The first and second inclined pivot axes form acute angles with the longitudinal axis of the manipulator arm, being inclined in opposite directions in the extended configuration of the arm.

#German printed patent application DE-AS No. 27 45 932 described a gear unit for a manipulator having two segments mounted following each other which are pivotally mounted in planes inclined to each other. The tool holder on the rear gear segment is rotatably mounted on a pivot axis coaxial with the main drive shaft axis of the manipulator.

#The above and other objects, features and advantages of my invention will become more readily apparent from the following specific description, reference being made to the accompanying highly diagrammatic drawing in which:

#FIG. 1 is a diagrammatic side view of the gear-head unit for a manipulator showing the relationship of the various components of the gear-head unit and their axes of rotation in its extended position;

#FIG. 2 is a diagrammatic side view of the apparatus according to FIG. 1 with a power take off inclined to the main drive shaft axis;

#The gear-head unit illustrated in FIG. 1 here corresponds to that of FIG. 1 of German Open Patent Application No. 34 28 748 and shows that an ambiguity for automatic control exists when a front plate 38 and/or tool holder in the rear segment 3 of the gear-head unit is mounted so that it is pivotable about an output shaft axis 46 coaxial to main drive shaft axis 4 and is rotated. Then the rotation of the tool about the output shaft axis 46 could also be possible by rotation of the front segment 1 of the gear-head unit about the main drive shaft axis 4. This ambiguity could be avoided only in cases where the front segment 1 can be nonrotatably mounted about the main drive shaft axis 4.

#Intermediate segment 2 of the gear-head unit can rotate about inclined pivot axis 5 with respect to front segment 1 and about inclined pivot axis 6 with respect to rear segment 3.

#FIG. 2 shows one way to avoid the abovementioned ambiguity. The output shaft axis 46 is inclined at an acute angle to the main drive shaft axis 4. Advantageously the output shaft axis 46 intersects both inclined axes 5 and 6 at the point of intersection 9 in order to make easy the computer control of the motion process. A pair of rear bevel gears 33 and 34 drive the front plate 38. Should a rotation of the front plate 38 or tool holder about the output shaft axis 46 occur, the drive for the front segment is not enabled. Thus ambiguity is avoided.