Weighing scale with low susceptibility to vibration

• US 4,379,495 A
• Filed: 04/27/1981
• Issued: 04/12/1983
• Est. Priority Date: 04/27/1981
• Status: Expired due to Fees

• Current Assignee: Premark FEG LLC (Illinois Tool Works Inc.)
• Original Assignee: Hobart Corporation (Illinois Tool Works Inc.)
• Inventors: Evans, Gary A., Cocks, Michael H.
• Primary Examiner(s): Hartary, Joseph W.
• Application Number:
  US06/258,212
• Time in Patent Office: 715 Days
• Field of Search: 177/25, 177/50, 177/185, 177/DIG. 3, 177/1, 364/466, 364/567, 364/734, 364/811, 364/575
• US Class Current: 177/1
• CPC Class Codes: G01G 23/3707 using a microprocessor

Abstract

A method and apparatus for determining a representative average weight reading is disclosed, based on a series of weight readings from a scale subject to vibrations. Signals are generated at regular intervals, representative of the weight readings from said scale. Each new weight signal is compared with the previous weight signal, and one of two alternative labels is assigned to each new weight signal according to whether it is greater or less than the previous weight signal, and the opposite of the previous label is assigned if the signals are equal. The weight signals occurring in a weight averaging interval, which extends from a label change in one direction to the next label change in the same direction, are then averaged.

Claims

1. A method for determining a representative average weight reading based on a series of weight readings from a scale subject to vibrations comprising the steps of

generating signals at regular intervals representative of the weight readings from said scale, and

averaging the weight signals occurring during one complete vibrational cycle, or integral multiple thereof.

2. A method for determining a representative average weight reading based on a series of weight readings from a scale subject to vibrations comprising the steps of

generating signals at regular intervals representative of the weight readings from said scale,

comparing each new weight signal with the previous weight signal, assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signal, and assigning the opposite of the previous label if the signals are equal, and

averaging the weight signals occurring in a weight averaging interval which extends from a label change in one direction to the next label change in the same direction.

3. A method for determining a representative average weight reading based on a series of weight readings from a scale subject to vibrations comprising the steps of

generating at regular intervals signals representative of the weight readings from said scale,

comparing each new weight signal with the previous weight signal, assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signal, and assigning the opposite of the previous label if the signals are equal, and

counting the number of weight signals occurring in a weight averaging interval which extends from a label change in one direction to the next label change in the same direction, and includes one intervening label change in the opposite direction, and

accumulating a total of the magnitudes of the weight signals generated during said weight averaging interval, and dividing the accumulated total of the weight signals by the number of weight signals occurring during said weight averaging interval thereby to provide an average weight reading.

4. Apparatus for determining a representative average weight reading from a series of weight readings from a scale subject to vibrations comprising

means for generating signals at regular intervals representative of the weight readings from said scale, and

means for comparing each new weight signal with the previous weight signal and for assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signal, and for assigning the opposite of the previous label if the signals are equal, and

means for averaging the weight signals occurring in a weight averaging interval extending from a label change in one direction to the next label change in the same direction.

5. The apparatus of claim 4 wherein said means for averaging the weight signals includes

counter means responsive to said comparing means for counting the number of weight signals occurring in said weight averaging interval,

means for accumulating the total of the magnitudes of the weight signals occurring during the weight averaging interval, and

means for dividing the accumulated total of the weight signals by the number of weight signals occurring during the weight averaging interval thereby to provide an average weight reading.

6. An apparatus for providing a representative digital average weight reading from a series of weight readings from a scale subject to vibrations comprising

means for generating an analog voltage signal representative of the weight reading from said scale, and

converter means for repeatedly generating digital weight signals in response to said analog voltage signal,

means for comparing each new digital weight signal with the previous digital weight signal and for assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signals, and for assigning the opposite of the previous label if the signals are equal, and

means for determining a digital average weight reading including

counter means responsive to said comparing means for counting the number of digital weight signals occurring in a weight averaging interval extending from a label change in one direction to the next label change in the same direction, and including one intervening label change in the opposite direction,

means responsive to the output of said counter means for accumulating a total of the magnitudes of the weight signals generated during the weight averaging interval, and

means for dividing the accumulated total of the weight signals by the number of weight signals occurring during the weight averaging interval thereby to provide a digital average weight reading.

7. An apparatus for determining motion in a weighing scale comprising

means for generating signals at regular intervals representative of weight readings from said scale, and

means for comparing each new weight signal with the previous weight signal and for assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signal, and for assigning the opposite of the previous label if the signals are equal,

means for averaging the weight signals occurring in a weight averaging interval extending from a label change in one direction to the next label change in the same direction,

means for comparing the most recent average weight signal with a previous average weight signal, and

means for indicating scale-in-motion when the difference in average weight signals exceeds a predetermined amount.

8. Apparatus for determining motion in a weighing scale comprising

means for generating an analog voltage signal representative of the weight on said scale,

means responsive to said analog voltage signal for generating digital weight signals at regular intervals,

means for comparing each new weight signal with the previous weight signal and for assigning one of two alternative labels to each new weight signal according to whether it is greater or less than the previous weight signal, and for assigning the opposite of the previous label if the signals are equal,

counter means for recording the number of successive weight signals of the same label, and means for indicating scale-in-motion when the number in said counter means exceeds a predetermined number,

means for averaging the weight signals occurring in a weight averaging interval extending from a label change in one direction to the next label change in the same direction when the number in said counter means does not exceed said predetermined number, and

means for comparing the most recent digital average weight signal with a previous digital average weight signal, and further means for indicating scale-in-motion when the difference in average weight signals exceeds a predetermined amount.