Electrical weigher using vibrating strings

Claim 1

A method of measuring forces by digitally computing the square of the ratio Q of a signal frequency to a constant basic frequency fxo using a constant reference frequency fo, the signal frequency lying between the value of the basic frequency and n times the basic frequency, comprising the steps of producing a series of electrical pulses Ix with a frequency Fx proportional to the signal frequency fx, feeding this series of pulses to a first counting means for counting, producing a series of electrical reference pulses Io with a frequency Fo n times greater than the basic frequency Fxo having the same proportional relationship to the frequency fxo, feeding the reference pulses Io for counting to a second counting means, feeding pulses Io in excess of pulses Ix to a third counting means during a first counting phase and during a following phase feeding every mth reference pulse to the third counting means, m and n being at least approximately equal, counting in all three counting means beginning at the same time, switching over the third counting means from the first counting phase to the second phase taking place when the second counting means has received so many reference pulses Io that its count ZZ stands at n X K, K being an arbitrary constant, and the first counting means counting the pulses Ix is switched off when the third counting means has reached a count equal to K(n-1), the count ZM of the first counting means then being at least approximately KQ2, the force to be measured being arranged to influence the tension of a vibrating string, the frequency of the vibration of the string controlling the frequency of the pulses Ix, while a reference string is caused to vibrate and the frequency Fo is proportional to the frequency of vibration of this latter string.

Claim 2

A method of measuring forces by digitally computing the square of the ratio Q of a signal frequency to a constant basic frequency fxo using a constant reference frequency fo, the signal frequency lying between the value of the basic frequency and n times the basic frequency, comprising the steps of producing a series of electrical pulses Ix with a frequency Fx proportional to the signal frequency fx, feeding this series of pulses to a first counting means for counting, producing a series of electrical reference pulses Io with a frequency Fo n times greater than the basic frequency Fxo having the same proportional relationship to the frequency fxo, feeding the reference pulses Io for counting to a second counting means, feeding pulses Io in excess of pulses Ix to a third counting means during a first counting phase and during a following phase feeding every mth reference pulse to the third counting means, m and n being at least approximately equal, counting in all three counting means beginning at the same time, switching over the third counting means from the first counting phase to the second phase taking place when the second counting means has received so many reference pulses Io that its count ZZ stands at n X K, K being an arbitrary constant, and the first counting means counting the pulses Ix is switched off when the third counting means has reached a count equal to K(n-1), the count ZM of the first counting means then being at least approximately KQ2, the force to be measured being arranged to influence the tension of a vibrating string, the frequency of the vibration of the string controlling the frequency of the pulses Ix, while a reference string is caused to vibrate and the frequency Fo is proportional to the frequency of vibration of this latter string.

Claim 10

An apparatus for weighing by digitally computing the square of the ratio Q of a signal frequency to a constant reference frequency, comprising: first, second, and third counting means 16, 11, 15, the first counting means 16 being arranged to be switched off by a switching off pulse; a switching means 12 which is arranged to be actuated by a control pulse from the second counting means 11; a scaling means 14; a mixing gate; a pulse generator 10 for producing signal pulses Ix, the output of this pulse generator being connected with the input of the first counting means 16; a second pulse generator 9 adapted to produce reference pulses Io, the output of the latter generator being connected with the second counting means, the second counting means being adapted to give a control pulse when it has reached a certain preset count, the third counting means passing a switch-off pulse to the first counting means, the input of the third counting means being connected in response to the switching means as controlled by the control pulse of the second counting means 11 successively with the output of the two pulse generators 9, 10 via the mixing gate 13, which is arranged only to allow the passage of pulses Io in excess of signal pulses Ix for counting, and with the output of the reference pulse generator via the scaling means; and a switch-on circuit means which is associated with the counting means and with the switch means, the switch-on circuit means serving to bring the switch means into a starting condition and to initiate operation of all three counting means, two strings being arranged to vibrate and control the frequency of the reference pulses and the signal pulses, the string controlling the frequency of the signal pulses being arranged to be connected with an article to be weighed.

Claim 11

An apparatus for weighing by digitally computing the square of the ratio Q of a signal frequency to a constant reference frequency, comprising: first, second, and third counting means 16, 11, 15, the first counting means 16 being arranged to be switched off by a switching off pulse; a switching means 12 which is arranged to be actuated by a control pulse from the second counting means 11; a scaling means 14; a mixing gate; a pulse generator 10 for producing signal pulses Ix, the output of this pulse generator being connected with the input of the first counting means 16; a second pulse generator 9 adapted to produce reference pulses Io, the output of the latter generator being connected with the second counting means, the second counting means being adapted to give a control pulse when it has reached a certain preset count, the third counting means passing a switch-off pulse to the first counting means, the input of the third counting means being connected in response to the switching means as controlled by the control pulse of the second counting means 11 successively with the output of the two pulse generators 9, 10 via the mixing gate 13, which is arranged only to allow the passage of pulses Io in excess of signal pulses Ix for counting, and with the output of the reference pulse generator via the scaling means; and a switch-on circuit means which is associated with the counting means and with the switch means, the switch-on circuit means serving to bring the switch means into a starting condition and to initiate operation of all three counting means, two strings being arranged to vibrate and control the frequency of the reference pulses and the signal pulses, the string controlling the frequency of the signal pulses being arranged to be connected with an article to be weighed.