Roberval Weighing Apparatus Limit Adjustment Mechanism
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Solution Overview
Problem
Conventional load cell-type weighing apparatuses face challenges in supporting moment loads, leading to damage and requiring delicate adjustments, which are costly and ineffective for large loads, especially in combination weighing applications.
Innovation Solution
A weighing apparatus utilizing a Roberval mechanism with a limit adjustment portion comprising a long first member and a long second member, where the second member's rotation changes the vertical space between the first member and a hole, allowing for easy adjustment and high resistance to moment loads, thereby preventing load cell deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a screw mechanism is used for adjustment, then delicate adjustment is achieved, but the adjustment process becomes complex and time-consuming
Solution Approach 1:
The patent extracts the adjustment function from a complex screw mechanism and implements it through a simple rotational operation of the limit mechanism body. The limiting member is integrated into the rotating body, allowing the limiting position to be adjusted by rotation alone, eliminating the need for separate screw adjustment components.
Solution Approach 2:
Instead of using a screw mechanism to move the limiting member along an axis, the patent inverts the approach by rotating the entire limit mechanism body to change the limiting position. This rotational adjustment simplifies the mechanism while achieving the same precision adjustment goal.
2Manufacturing precision
If sheet metal parts are used for the limit mechanism, then delicate adjustment is enabled, but the mechanism cannot bear large loads
Solution Approach 1:
The patent employs a composite structure combining a rigid rod-like limiting member with a rotatable limit mechanism body. The limiting member provides high strength for load bearing, while the rotatable body enables precise adjustment. This composite approach integrates both strength and adjustability in a single mechanism.
3Device complexity
If the limit mechanism is supported at a single point, then the structure is simplified, but moment loads cause damage to the load cell
Solution Approach 1:
The patent positions the limit mechanism laterally adjacent to the load cell rather than directly supporting it vertically. This lateral positioning allows the mechanism to restrict movement in the vertical direction through rotation, while moment loads are directed to the lateral support structure, preventing damage to the load cell.
Data Source
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AI summary
A weighing apparatus (1) configured to weigh a mass value of an article, using a Roberval mechanism, the weighing apparatus including: a load cell (2); a limit adjustment portion (3) including a long first member (31) and a long second member(32) ; a first support portion (4) that is a member connected to a free end side of the load cell and through which the second member passes; and a second support portion (5) that is a member connected to a fixed end side of the load cell and a main body of the weighing apparatus, and includes a hole into which the first member is fit. The second member is rotated, a space (S) formed between the first member and the hole is changed in conjunction with the rotation.