Weight display system and method

Claim 2

In a system for displaying the net weight of a load on a scale from a digital signal representative of the gross weight of the load, bidirectional counting means comprising a counter having an up counting input and a down counting input and gating means for steering the load signal to the counter inputs, means for storing a predetermined count in digital form, means for transferring the stored count to the counting means and conditioning the gating means to apply the load signal to the down counting input at the beginning of a counting period, and means responsive to the count in the counter for conditioning the gating means to apply the load signal to the up counting input when the count reaches a predetermined level.

Claim 3

A system as in claim 1 together with manually operable means for inhibiting the transfer of the stored count to the counting means and applying the load signal to the up counting input at the beginning of the counting period.

Claim 4

A system as in claim 1 further including bistable logic means having first and second outputs for delivering control signals to the gating means.

Claim 5

A system as in claim 1 wherein the means for storing a predetermined count includes a storage register connected to the counter for storing the count registered therein at a predetermined time.

Claim 6

A system as in claim 1 wherein the means for storing a predetermined count includes means for generating a digital signal corresponding to said count.

Claim 7

A system as in claim 1 wherein the means responsive to the count includes a zero detector.

Claim 8

In a system for displaying the net weight of a load on a scale from a digital signal representative of the gross weight of the load, a bidirectional counter having up and down counting inputs, memory means connected to the output of the counter, manually operable switch means for locking the count from the counter in the storage means, gating means having first and second outputs connected respectively to the up and down counting inputs of the counter, said gating means also having a load signal input and a pair of control inputs, a bistable flip-flop having first and second outputs connected to the control inputs of the gating means, a one-shot multivibrator having a trigger input connected to an overflow output on the counter and an output connected to one input of the flip-flop, the output of said multivibrator also being connected to the counter for causing the count stored in the memory to be transferred to said counter, and a zero detector having an input connected to the counter and an output connected to an input of the flip-flop, said flip-flop and gating means being arranged in such manner that the load signal is applied to the down counting input in response to a signal from the multivibrator and to the up counting input in response to a signal from the zero detector.

Claim 9

In a system for displaying the net weight of a load on a scale from a digital signal representative of the gross weight of the load, a bidirectional counter having up and down counting inputs, memory means connected to the output of the counter, manually operable switch means for locking the count from the counter in the storage means, gating means having first and second outputs connected respectively to the up and down counting inputs of the counter, said gating means also having a load signal input and a pair of control inputs, a bistable flip-flop having first and second outputs connected to the control inputs of the gating means, a one-shot multivibrator having a trigger input connected to an overflow output on the counter and an output connected to one input of the flip-flop, the output of said multivibrator also being connected to the counter for causing the count stored in the memory to be transferred to said counter, and a zero detector having an input connected to the counter and an output connected to an input of the flip-flop, said flip-flop and gating means being arranged in such manner that the load signal is applied to the down counting input in response to a signal from the multivibrator and to the up counting input in response to a signal from the zero detector.

Claim 10

A system as in claim 7 wherein said switching means is adapted for inhibiting the operation of the one-shot multivibrator.

Claim 11

In a method for displaying the net weight of a load on a scale from an analog signal corresponding to the gross weight of the load, the steps of: converting the analog signal to a digital signal by operating a clock at a predetermined rate, charging a capacitor at a rate corresponding the magnitude of the analog signal for a predetermined period of time during the first portion of a cycle, discharging the capacitor at a predetermined rate during a second portion of the cycle, and utilizing the pulses produced by the clock while the capacitor is discharging as the load signal; storing in digital form a count representative of tare weight; resetting the counter at the start of the first portion of the cycle to an initial level less than the capacity of the counter by an amount corresponding to the number of pulses generated by the clock during the first portion of the cycle; advancing the counter is an upward direction until an overflow occurs; setting the counter at the start of the second portion of the counting period to a count corresponding to the stored count; and counting the load signal into the counter during the second portion of the cycle by first advancing the counter in a downward direction from the level of the stored count toward zero and thereafter advancing the counter in an upward direction.

Claim 12

In a method for displaying the net weight of a load on a scale from an analog signal corresponding to the gross weight of the load, the steps of: converting the analog signal to a digital signal by operating a clock at a predetermined rate, charging a capacitor at a rate corresponding the magnitude of the analog signal for a predetermined period of time during the first portion of a cycle, discharging the capacitor at a predetermined rate during a second portion of the cycle, and utilizing the pulses produced by the clock while the capacitor is discharging as the load signal; storing in digital form a count representative of tare weight; resetting the counter at the start of the first portion of the cycle to an initial level less than the capacity of the counter by an amount corresponding to the number of pulses generated by the clock during the first portion of the cycle; advancing the counter is an upward direction until an overflow occurs; setting the counter at the start of the second portion of the counting period to a count corresponding to the stored count; and counting the load signal into the counter during the second portion of the cycle by first advancing the counter in a downward direction from the level of the stored count toward zero and thereafter advancing the counter in an upward direction.

Claim 13

In a system for displaying the net weight of a load on a scale from a digital signal representative of the gross weight of the load, bidirectional counting means for counting the load signal, said counting means having an up counting mode and a down counting mode, means for storing a predetermined count in digital form, means including a one-shot multivibrator having a trigger input connected to the overflow output of the counting means for transferring the stored count to the counting means and setting the counting means in its down counting mode, and means responsive to the count in the counting means for switching the counting means to its up counting mode when the count reaches a predetermined level.

Claim 14

In a system for displaying the net weight of a load on a scale from a digital signal representative of the gross weight of the load, bidirectional counting means for counting the load signal, said counting means having an up counting mode and a down counting mode, means for storing a predetermined count in digital form, means including a one-shot multivibrator having a trigger input connected to the overflow output of the counting means for transferring the stored count to the counting means and setting the counting means in its down counting mode, and means responsive to the count in the counting means for switching the counting means to its up counting mode when the count reaches a predetermined level.

Claim 15

In a system for determining changes in the weight of a load on a scale from a digital signal representative of the gross weight of the load, bidirectional counting means having an up counting mode in which the count in the counting means advances in an upward direction in response to an input signal and a down counting mode in which the count advances in a downward direction in response to an input signal, means for applying the load signal to the counting means as an input signal, memory means for storing the count registered by the counting means at a desired time, means for transferring the stored count from the memory means to the counting means and setting the counting means in its down counting mode at the beginning of a counting period, means responsive to the count in the counting means for switching the counting means to its up counting mode when it has counted down to zero, and manually operable switch means for conditioning the memory means to store the count registered by the counting means at the time the switch means is actuated whereby the count registered by the counting means at the end of the counting period corresponds to the net change in the weight of the load from the time the switch means is actuated.

Claim 16

In a system for determining changes in the weight of a load on a scale from a digital signal representative of the gross weight of the load, bidirectional counting means having an up counting mode in which the count in the counting means advances in an upward direction in response to an input signal and a down counting mode in which the count advances in a downward direction in response to an input signal, means for applying the load signal to the counting means as an input signal, memory means for storing the count registered by the counting means at a desired time, means for transferring the stored count from the memory means to the counting means and setting the counting means in its down counting mode at the beginning of a counting period, means responsive to the count in the counting means for switching the counting means to its up counting mode when it has counted down to zero, and manually operable switch means for conditioning the memory means to store the count registered by the counting means at the time the switch means is actuated whereby the count registered by the counting means at the end of the counting period corresponds to the net change in the weight of the load from the time the switch means is actuated.

Claim 17

A system as in claim 11 further including means for displaying the count in the counting means at the end of a counting period and means for displaying a minus sign with the count in the event that the counting means is still in its down counting mode at the end of the counting period.

Claim 18

A system as in claim 11 wherein the switch means comprises a pushbutton switch which when depressed inhibits the transfer of the stored count to the counting means and inhibits the setting of the counting means in its down counting mode whereby the counting means registers a count corresponding to the gross weight of the load as long as the switch is depressed, the count being stored in the memory means when the depressed switch is released.