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Exploring the attribution of crane (hanging) scales(III)

Looking at the current International Recommendations on Weighing issued by the International Organization of Legal Metrology, I believe that International Recommendation R51, Automatic Subtesting of Weighing Instruments, called a “truck-mounted scale”.

Vehicle-mounted scales: This is a complete set of inspection scales designed for this particular purpose and mounted on a vehicle. In the case of crane scales, the crane (truck crane, overhead crane, gantry, bridge, gantry crane, etc.) can be referred to as the “vehicle”, while the crane scale (hook scale, hook scale, etc.) can be referred to as the weighing section.

Automatic catch weighing instrument (automatic catch weighing instrument), where the word “catch” can be translated as: seize, hold; catch, capture, capture. Crane scales can also be referred to as “catching” or “holding”.

R51 Scales can be categorized into two basic categories according to their purpose: X or Y.

Category X applies only to sub-screening scales, which are used to inspect pre-packaged products in accordance with the international recommendations of OIML R87, Net Content of Packaged Goods. Category Y is used for all other automatic sorting scales, such as price labeling and labeling equipment. Scales, postal scales, and shipping scales, as well as many scales that are used to weigh bulk single loads.

In terms of the types of scales presented in this definition, if “price labeling scales” and “postal scales” can be classified as automatic scales, then “mobile scales” can hardly be considered as “a scale that weighs automatically according to a predetermined process without the intervention of an operator”, e.g. vehiclemounted scales (garbage scales), vehicle combination scales (forklift scales, loader scales, etc.) do not fit into this concept.

The R51 has Class X and Class Y accuracy levels, so if the crane scale under inspection can be tested to a level that is achievable, it will be used in accordance with that level. Since the maximum allowable error levels for nonautomatic operation of the R51, X Class III and Y(a) Class levels are basically on the same level as the R76′s Class III, both Tables 1 and 2 are acceptable.

How to judge the properties of a scale, not just look at its surface phenomenon, but should look at its situation in actual use. Now some domestic measurement technology institutions have crane scale testing equipment, but the accuracy of these devices is on the crane scale test static performance, is no practical use of value.

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