Electronic balance for measuring masses or forces

• US 3,885,427 A
• Filed: 08/22/1972
• Issued: 05/27/1975
• Est. Priority Date: 05/16/1972
• Status: Expired due to Term

• Current Assignee: K-Tron Patent AG
• Original Assignee: Domenic Melcher, Mario Gallo
• Inventors: Melcher, Domenic, Gallo, Mario
• Primary Examiner(s): Ruehl, Charles A.
• Application Number:
  US05/282,867
• Time in Patent Office: 1,008 Days
• Field of Search: 73/DIG.1,517AV,141R 324/79D,14D 235/92WT,92FQ,150.3,151.33 177/210
• US Class Current: 73/862.59
• CPC Class Codes: G01G 3/16 measuring variations of frequency of oscillations of the body
• CPC Class Codes: G01L 1/10 by measuring variations of frequency of stressed vibrating elements, e.g. of stressed strings using resistance strain gauges G01L1/22
• CPC Class Codes: Y10S 73/01 Vibration

Abstract

A balance for measuring masses and forces comprising a phaselocked frequency multiplier which multiplies the string frequency F1 that is raised by the process of measurement with a predetermined fixed factor in such manner that the multiplied frequency retains a constant phase relationship with the original frequency and wherein the number of full cycles of the multiplied frequency F1 is counted for a period of time corresponding to a given number of full cycles of the frequency F2, which frequency is reduced by the measuring process.

Claims

1. An electronic balance, comprising:

a frame;

a weighing platform;

first and second pretensioned electronically excited transversely vibrating strings;

means coupling said strings between said frame and said weighing platform such that the frequency of said first string is increased and the frequency of said second string is decreased as a function of a force exerted on said weighing platform;

means for detecting the frequency generated by said first string;

phase-locked frequency multiplying means coupled to said detecting means for multiplying the frequency generated by said first string with a predetermined fixed factor in such a manner that the multiplied frequency retains a constant phase relationship with the original frequency generated by said first string;

first counting means for detecting and counting a given number of full cycles of the frequency generated by said second string;

second counting means for counting the number of full cycles of the multiplied first string frequency during the period of time said given number of full cycles of the second string frequency is counted; and

means for displaying the output of said second counting means.