SCARA Robot Cross Arm Mechanism for Heavy Workpiece Conveyance
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Solution Overview
Problem
Existing workpiece conveying apparatuses face challenges in efficiently replacing attachment parts due to manual intervention, leading to reduced production efficiency and increased downtime, and they struggle with high-speed and stable conveyance of heavy workpieces due to structural limitations in arm movement and weight distribution.
Innovation Solution
A workpiece conveying apparatus with two SCARA robots and a cross arm mechanism that allows for independent movement in the Z-axis and Y-axis directions, featuring a shifting device and sliding device configuration to enable flexible conveyance posture changes, reducing the need for manual part replacement and minimizing weight and size while maintaining high-speed operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the servomotor is removed from the conveying apparatus for attachment part replacement, then the attachment part can be automatically removed, but the position information of the shift driving mechanism is lost requiring original point setting work
Solution Approach 1:
The encoder is positioned on the attachment part rather than on the conveying apparatus, so that when the attachment part is removed and reinstalled, the encoder automatically restores the position information without requiring original point setting work. This preliminary positioning arrangement eliminates the time-consuming recalibration process.
2Reliability
If manual work is used for attachment part replacement, then position information is maintained, but the replacement process takes a very long time and production is stopped
Solution Approach 1:
The encoder mounted on the attachment part serves itself by automatically maintaining position information through its own position during removal and reinstallation, eliminating the need for manual intervention and original point setting work, thus both maintaining reliability and improving productivity.
3Force
If a linear guide is used to support heavy workpieces, then the workpiece can be supported, but micromovement caused by vibration occurs and the linear guide receives large bending moment and torsional moment
Solution Approach 1:
The support function is divided between the linear guide (which handles the heavy workpiece weight) and the ball screw mechanism (which provides precise positioning and stability). This segmentation allows each component to optimize its function without being overloaded.
Solution Approach 2:
The linear guide and ball screw mechanism are combined in the same assembly, with the ball screw rod passing through the linear guide. This merging allows the system to simultaneously achieve heavy load support from the linear guide and vibration resistance from the rigid ball screw structure.
Data Source
AI summary
A workpiece conveying apparatus includes: two SCARA robots each including a first arm supported on a raising and lowering frame through intermediation of a first joint, a second arm supported through intermediation of a second joint, a first arm driving mechanism configured to drive the first arm to rotate, and a second arm driving mechanism configured to drive the second arm to rotate; a raising and lowering mechanism for the two SCARA robots; a cross arm configured to couple distal ends of the second arms; a workpiece holding unit configured to releasably hold the workpiece; shifting devices provided to the cross arm and configured to shift a drive-side shifting member; and sliding devices provided to the workpiece holding unit and configured to shift the tool holder by an operation of causing the driven-side shifting member to be driven by the drive-side shifting member.