Conveyance Device Arm Weight Reduction via Cable Transmission
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Solution Overview
Problem
Conveyance devices face challenges in conveying workpieces at high speeds due to large weight and moment of inertia, which leads to difficulties in precise positioning and potential cable breakage from repeated winding and unwinding.
Innovation Solution
A conveyance device design featuring a rotary motion mechanism with a rectilinear movement mechanism placed inside the rotation transmission mechanism, reducing weight and moment of inertia, and utilizing a screw shaft and nut system to enable high-speed rectilinear movement without rotating, thus preventing cable breakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If motors are provided in the tip portions of arms to enable horizontal rotation, then the arm can be positioned accurately, but the weight and moment of inertia of the arm become large, making high-speed conveyance difficult
Solution Approach 1:
The patent extracts the motor from the arm tip portion and relocates it to the base portion. Specifically, the first motor is mounted on the base to rotate the first arm, and the second motor is mounted on the first arm to rotate the second arm. This extraction of motors from the arm structure reduces the weight and moment of inertia of the moving arms while maintaining positioning accuracy through the transmission mechanisms.
Solution Approach 2:
The patent introduces cable-driven transmission mechanisms as intermediaries between the motors and the arms. The first cable transmits rotational force from the first motor to rotate the first arm, and the second cable transmits rotational force from the second motor to rotate the second arm. These intermediary cable transmission systems enable accurate arm positioning without requiring motors to be mounted at the arm tips, thus reducing arm weight and moment of inertia.
2Ease of operation
If the arm mechanism and conveyance device body rotate simultaneously when the second motor is driven, then the arm can be turned, but the moment of inertia becomes large and high-speed conveyance becomes difficult
Solution Approach 1:
The patent segments the rotation functions into independent axes. The first motor independently controls the rotation of the first arm about the first axis, and the second motor independently controls the rotation of the second arm about the second axis. This segmentation allows each motor to control only its designated arm rotation without causing simultaneous rotation of the entire conveyance device body, thereby reducing the moment of inertia and enabling high-speed conveyance.
Solution Approach 2:
The patent replaces the traditional mechanical gear transmission system with a cable-driven transmission system. Instead of using gears that would require the conveyance device body to rotate along with the arm mechanism, the cable transmission system allows the second motor to rotate the second arm independently while the first motor controls the first arm rotation. This substitution eliminates the coupled rotation problem and reduces the effective moment of inertia.
3Measurement precision
If cables are repeatedly wound and unwound on the conveyance device during arm rotation, then the arm can be positioned, but the cable is burdened and may break
Solution Approach 1:
The patent extracts the cable winding function from the conveyance device body and relocates it to dedicated cable reels mounted on the base. The first cable is wound on a first cable reel and the second cable is wound on a second cable reel. This extraction allows the cables to be wound and unwound in a controlled manner on the base rather than on the rotating conveyance device body, reducing cable burden and preventing breakage while maintaining arm positioning capability.
Solution Approach 2:
The patent introduces cable reels as intermediary components between the motors and the cables. The first cable reel mediates the winding and unwinding of the first cable driven by the first motor, and the second cable reel mediates the winding and unwinding of the second cable driven by the second motor. These intermediary cable reels provide controlled cable management, reducing abrupt tensions and burdens on the cables during arm positioning operations, thereby preventing cable breakage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables high-speed and precise conveyance of workpieces to arbitrary positions with reduced moment of inertia and minimized risk of cable failure.
Implementation Method 1
utilizing a screw shaft and nut system to enable high-speed rectilinear movement without rotating
Data Source
AI summary
Provided is a conveyance device capable of achieving high-speed conveyance of a workpiece through arm weight reduction and inertial moment reduction. The conveyance device 100 capable of rotating and linearly moving an arm 121 comprises: a rotary motion mechanism 101 which has a first rotary shaft 108 capable of rotating about a first axis 103; a rotation transmission mechanism 109 which is connected to the first rotary shaft 108 and is capable of rotating the arm 121 when the rotation transmission mechanism 109 is caused to rotate about a second axis 106 in response to rotation of the first rotary shaft 108; and a linear movement mechanism 104 which is capable of linearly moving the arm 121. The linear movement mechanism 104 is disposed on the inner side of the rotation transmission mechanism 109 in such a manner as not to rotate in response to rotation of the first rotary shaft 108.