Balance with a mechanical coupling area for a calibration weight
AssigneeMettler-Toledo AG
InventorsHans-Rudolf Burkhard, Ferdinand Schneider
Life of this patent
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Abstract
In a balance with a parallel-guided load receiver (5) and a force-reduction mechanism using a series of two levers (18, 30), the input arm (17) of the first lever (18) to which the weight force of the load to be weighed is applied is extended into the space outside of the load receiver (5) and past a force transducer (43) arranged in that space, the end of the extension being equipped with a coupling area (58) for a calibration weight (59). This accomplishes a large lever-reduction of the calibration force in combination with a compact configuration, thus allowing a full-load calibration of the balance to be performed with a relatively small calibration weight (59).
Claims14
A balance that is equipped with
- A) a load receiver (5) that serves to introduce a weight force of a load to be weighed and is constrained relative to a stationary part (6) of the balance by two guide links (7, 7′) running in parallel at a distance from each other and each of them being connected by thin flexible portions (10, 11) at one end to the load receiver (5) and by thin flexible portions (9, 12) at an opposite end to a stationary part of the balance for parallel-guided displacement of the load receiver (5) within a plane defined by a parallelogram through the four ends of the guide links (7, 7′);
- B) a force transducer (43) that serves to convert the weight force into an electrical measuring signal, and
- C) a lever mechanism which has a first lever (18) and a second lever (30) as well as a coupling area (58) for the releasable connection with a calibration weight (59) and which serves to transfer the weight force from the load receiver (5) to the force transducer (43), wherein
- the first lever (18) has an input arm (17) extending from a thin flexible coupling portion (14) of a coupling member (16), connected with the load receiver (5) for force-transfer and formed in an area of the load receiver (5) facing towards the stationary part (6), to a first support (23), serving as lever fulcrum and formed on a portion (19) of the stationary part (6) facing towards the load receiver (5);
- and
- the first lever (18) also has an output arm (17′) extending from the support (23) in the direction towards the stationary part (6);
- and
- the second lever (30) is held by a second support (35) that serves as fulcrum and is formed on the portion (19) of the stationary part (6) facing towards the load receiver (5), wherein further the second lever is coupled for force transfer with the output arm (17′) of the first lever (18) and wherein the second lever has a portion (42) extending in the direction towards the load receiver (5) and serving to transfer the weight force to the force transducer (43);
- comprising the improvement that
- the input arm (17) of the first lever (18) has an extension which reaches beyond the thin flexible coupling portion (14) as far as a space adjacent to a side (4′) of the load receiver (5) facing away from the stationary part (6), the extension in said space being equipped with the coupling area (58) for the calibration weight (59) so that a calibration weight acts immediately on the input arm (17) of the first lever (18) via the extension.
Dependencies are inferred from the claim text.