Closed-Chamber Weighing Pan Transfer for Precise Automated Weighing
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Solution Overview
Problem
Existing weighing systems face challenges in automating the transfer of objects to and from a weighing pan within a closed chamber, particularly in high-precision balances, while ensuring reproducibility and minimizing interference from external factors.
Innovation Solution
A weighing device with a weight preparation table and weighing pan that are displaceable relative to each other along two linear axes, allowing automated and reproducible placement and removal of objects within a closed chamber, without external access, and capable of handling multiple objects simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the weighing chamber is opened for transferring weights, then access to the weighing pan is enabled, but measurement accuracy deteriorates due to air movements and temperature fluctuations
Solution Approach 1:
The transfer process is segmented into two distinct locations: a preparation area outside the weighing chamber and a weighing area inside the chamber. The robotic device transports weights between these segmented zones, allowing preparation operations without chamber opening while maintaining measurement integrity inside the closed chamber.
Solution Approach 2:
The robotic device serves as an intermediary mechanism that bridges the external preparation area and the internal weighing area. It transfers weights through the chamber opening only when necessary, then maintains closure, thus mediating between the need for weight access and the need for measurement stability.
2Productivity
If manual transfer of weights is used, then operation simplicity is maintained, but productivity decreases due to time-consuming repeated placement and removal
Solution Approach 1:
The robotic device performs the transfer operations autonomously without requiring manual intervention. It automatically picks up weights from the preparation area, transports them to the weighing pan, and returns them after measurement, enabling the system to serve itself in the weight transfer process.
Solution Approach 2:
The robotic device is designed with multi-functionality to perform multiple operations: picking up weights, transporting them horizontally and vertically, positioning them on the weighing pan, and retrieving them after measurement. This universal transfer mechanism handles all weight transfer tasks within the system.
3Productivity
If rapid weight transfer is performed, then productivity is improved, but measurement precision deteriorates due to induced oscillations and vibrations
Solution Approach 1:
The robotic device applies preliminary anti-action by carefully controlling its movement speed and acceleration during weight transfer. It moves slowly and smoothly when approaching the weighing pan and during placement, preventing vibrations that would interfere with measurements, while maintaining efficient transfer cycles overall.
Solution Approach 2:
The transfer process uses periodic action with distinct phases: rapid transport phases for efficiency, followed by slow, controlled placement phases for precision. The robotic device alternates between these speed regimes, performing quick movements during transport and deliberately slow movements during weight placement and removal.
4Productivity
If single weight transfer is used, then placement precision is maintained, but productivity decreases due to sequential transfer of multiple weights
Solution Approach 1:
The robotic device merges multiple weight transfer operations into a single integrated process. It can pick up multiple weights from the preparation area, transport them together, and place them on the weighing pan in sequence without returning to the preparation area between each weight, combining multiple transfers into one continuous operation.
Data Source
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AI summary
Disclosed is a weighing device (1) which comprises at least one weight preparation table (16, 17) and a weighing pan (14) functionally connected to a load cell. The at least one weight preparation table (16, 17) and the weighing pan (14) are displaceable relative to each other along at least two linear axes (x, z), wherein a first one of the at least two linear axes is a horizontal axis (x) and a second one of the at least two linear axes is a vertical axis (z), and wherein displaceability is restricted to purely linear translational displacement along the at least two linear axes. A horizontal displacement is such that the at least one weight preparation table is positionable at at least two different positions relative to the weighing pan (14). In a first one of the at least two different positions, the at least one weight preparation table is laterally offset from a centre (18) of the weighing pan in a vertical view. In a second one of the at least two different positions, the at least one weight preparation table is overlapping the centre of the weighing pan in the vertical view. The weighing pan and the at least one preparation table are enclosed within a weighing chamber (11) of the weighing device, wherein the weighing device is configured to restrict any motion of the at least one weight preparation table, if any, and of the weighing pan, if any, to within the weighing chamber. Further disclosed are a system comprising the weighing device and a method for weight determination.