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United States Patent 5,167,290
Borchard Dec. 1, 1992

Springs for use in a compact self-adjusting weighing system

Inventors: Borchard; John (97A Lowell Ave., Newton, MA 02160).
Appl. No.: 587,109
Filed: Sept. 24, 1990
Intl. Cl.: G01G 3/00; G01G 3/14;
U.S. Cl.: 177/225.; 177/210.C;
Field of Search: 225;210 C

References Cited

U.S. Patent Documents

2,087,354 Jul., 1937 Muffly 177/225
3,565,195 Feb., 1972 Miller et al.
3,831,688 Aug., 1974 Phipps
4,266,263 May, 1981 Haberl et al.
4,295,379 Oct., 1981 Zura
4,463,614 Aug., 1984 Lee
4,482,022 Oct., 1984 Komoto
4,572,006 Feb., 1986 Wolfendale
4,585,082 Apr., 1986 Harrington et al. 177/210 C
4,629,019 Dec., 1986 Harrington et al. 177/210 C
4,738,324 Apr., 1988 Borchard
4,799,558 Jan., 1989 Griffen
4,825,967 May, 1989 Sakamoto et al.
4,828,057 May, 1989 Borchard
4,862,978 Sept., 1989 Borchard
4,862,979 Jul., 1989 Borchard
4,869,331 Sept., 1989 Borchard
4,874,051 Oct., 1989 Borchard
4,913,248 Apr., 1990 Zakai
4,960,177 Oct., 1990 Holm-Kennedy et al.
4,964,478 Nov., 1990 Stadler et al.

Primary Examiner: Miller, Jr.; George H.

Abstract

Springs for use in a weighing system for measuring gems and other very light masses. A pan and sensor assembly is used in which the springs are sandwiched between the plates of the sensor assembly. The springs have a generally conic cross-section and include holes for releasing air pressure when the pan and sensor assembly is compressed. In a preferred embodiment, grooves are provided in the surface of the springs which allow the springs to compress, in a bellows or accordion-like fashion, substantially parallel to a central axis. One large spring or a plurality of springs may be used in a weighing system. The weighing system uses three or more transducers about the pan to measure the weight of the mass, and correlates the values measured by each transducer for a given mass, at given locations, to arrive at a true weight value for the mass in spite of its potentially off-center location on the system's holding pan.

17 Claims, 20 Drawing Figures

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