Combination weighing machine

A combination weighing machine comprising:

• a plurality of weighing units for weighing respective quantities of product to provide corresponding weight signals, each of said weighing units including a plurality of product containers, a single weight sensor for measuring the total weight of product in said containers, and a plurality of weight memories corresponding respectively to said containers;
• weight calculating means for calculating the weights of product in the respective containers from the contents of said weight memories and the total weight from said weight sensor and storing the calculated weights in said corresponding weight memories;
• combination arithmetic means for combining said weight signals to select a combination having a sum weight satisfying a predetermined weight condition, said combination arithmetic means being operable to select a combination based upon the contents of said weight memories;
• and
• a plurality of chutes for collecting product discharged from said weighing units, said chutes corresponding respectively to said product containers of each weighing unit, said combination arithmetic means being operable to select a combination based only upon the contents of said memories belonging to the product containers corresponding to each chute.

A combination weighing machine comprising a plurality of weighing units, each including a plurality of product containers adapted to hold separate quantities of product, a single weight sensor associated with each weighing unit for measuring the total weight of product in the containers of the weighing unit, memory means for storing first weight values corresponding to the weight of product in a first product container of at least some of the weighing units as sensed by the respective weight sensors and second weight values corresponding to the weight of product in a second product container of at least some of the weighing units, means for calculating each of said second weight values by computing the difference between said first weight value and a third weight value corresponding to the total weight of product in said first and second product containers of a respective weighing unit as sensed by the respective weight sensor, a first chute for collecting product discharged from certain of said containers of the weighing units, a second chute for collecting product discharged from other of said containers of the weighing units, and combination arithmetic means for combining said first and/or second weight values of at least some of the weighing units as stored in said memory means to select a combination of weight values having a sum weight value satisfying a predetermined weight condition, said combination arithmetic means being operable to select a first combination from the weights of product in said certain containers and a second combination from the weights of product in said other containers.

A method of combination weighing utilizing a plurality of weighing units, each unit comprising a plurality of product containers and a single weight sensor for measuring the total weight of product in the containers, and further utilizing memory means for storing weight values corresponding to the weights of product in the containers of the weighing units, said method comprising:

• (a) storing in said memory means first weight values corresponding to the weight of product in a first product container of at least some of the weighing units as sensed by the respective weight sensors;
• (b) storing in said memory means second weight values corresponding to the weight of product in a second product container of at least some of the weighing units, each second weight value being determined by computing the difference between said first weight value and a third weight value corresponding to the total weight of product in said first and second product containers of a respective weighing unit as sensed by the respective weight sensor;
• (c) effecting a combination arithmethic operation using said first and/or second weight values of at least some of the weighing units as stored in said memory means to select a combination of values having a sum weight value satisfying a predetermined weight condition;
• (d) combining said first and/or second weight values of certain product containers of at least some of the weighing units to select a first combination of values having a sum weight value satisfying a predetermined weight condition;
• (e) combining said first and/or second weight values of other product containers of at least some of the weighing units to select a combination of values having a sum weight value satisfying a predetermined weight condition;
• (f) unloading the product containers corresponding to said first selected combination into a first product delivery system;
• and
• (g) unloading the product containers corresponding to said second selected combination into a second product delivery system.

A combination weighing apparatus for producing a weight of product closely approximating a target weight comprising:

• a plurality of weigh scales, each scale having multiple bins for receiving and discharging multiple quantities of product respectively and a sensor detecting the aggregate weight of product in the bins of the scale at any given time and generating a corresponding weight signal;
• at least two discharge chutes for receiving product from the plurality of weighing scales;
• feeder means for delivering a quantity of product to each bin of the scales;
• reading and storing means connected with the plurality of scales and responsive to the generated weight signals for determining and storing separately the weight of product in each bin of the scales;
• combination searching means connected with the reading and storing means for selecting from the stored weights an acceptable combination of bins that yields a total weight of product closely approximating a target weight;
• and
• control means, responsive to the combination searching means, for discharging product in the bins associated with one acceptable combination into the same discharge chute.

A method of obtaining a weight of product closely approximating a target weight by combining selected weights of product from a plurality of weighing scales, comprising the steps of:

• providing on each weight scale of the plurality a number of at least two bins for receiving and discharging weights of product, each weigh scale generating a weight signal representative of the aggregate weight of product in all of the bins of the scale at any given time;
• delivering a quantity of product to each bin of the scale in the plurality, each bin receiving the delivered product at a time different from the other bins of the same scale;
• reading the weight signals from the scales after each delivery, and determining the weight of product in each bin from the read weight signals;
• searching the determined weights of product in the bins for selection of an acceptable combination of bins that yields a combined weight of product closely approximating a target weight;
• providing a plurality of discharge paths and receivers equal in number to the number of bins on each scale for discharging to the receivers combined weights of product from a corresponding plurality of acceptable combinations of bins without refilling the bins;
• and
• discharging the combined weight of product into the receivers from the acceptable combination of bins.