Abstract: A low profile weight sensor for a weight sensing system for monitoring article input and removal from article storage apparatus comprises a plate or I-shaped bar support member having first and second sections, an integrally formed linkage system for connecting the first and second sections such that the sections are substantially coplanar in an unloaded state, and are relatively displaceable with respect to each other in response to a weight load applied to one of the sections; and a magnetic transducer mounted on surfaces extending in the thickness direction of the plate/bar member for producing an electrical output signal responsive to relative displacement of the first and second sections.

Abstract: A low power consumption controller for weight based article input and removal monitoring apparatus comprises a continuously active weight monitoring section responsive to the weight sensor output(s) for producing a first control signal in response to predetermined changes in the sensed weight; and a signal analysis section switchable from an inactive mode to an active mode in response to the first control signal for analyzing the sensor output(s), and for controlling the operation of the weight monitoring section.

Abstract: The feeding system comprises one or more material storage devices and a discharge device associated with each storage device. Each discharge device comprises a conveyor channel tilted upwardly and away from its inlet arranged to be connected with the outlet of the storage device. A chute is adapted to be loosenably suspended, rapidly and simply, on the lower longitudinal side of the conveyor channel in a working position, a sampling position or in an emptying position, as required. In its working position the chute is positioned parallel to the conveyor channel, while the upper outlet of the conveyor channel opens into the chute at the upper end of the latter. In its sampling position the chute is tilted downward and away from the upper end of the conveyor channel at a right angle to the latter. In its emptying position the chute is tilted downward and away from the lower end, i.e. from the start of the conveyor channel and at a right angle to the latter.

Abstract: A weigh feeding system using a stochastic controller wherein the weight of material and the position of a material discharge actuator are sensed, and an estimate of the mass flow state of the material being discharged is created by use of a Kalman filter process. Plant noise processes and measurement noise processes, which affect the measured weight and actuator position signal, are modeled as stochastic processes and are used, in combination with the sensed weight and actuator position signals, to calculate the estimated mass flow state. The noise models are modified to account for disturbances. The estimated mass flow state signal is used to calculate a motor feedback signal which, in turn, is used to control the speed of the discharge apparatus. In this manner, the mass flow of the material actually being discharged is driven to a desired mass flow with minimum error variance in the presence of unavoidable plant and measurement noise.

Abstract: An actuator for a vibratory material feeder comprises a base, a tray support, at least one spring for mechanically coupling the base and tray support, and a spring mount for mounting the spring to an actuator mounting surface on one of the base and tray support. The spring mount comprises first and second bearings each having a spring-abutting surface for supporting the spring therebetween, an arcuate surface and at least one hole therethrough; first and second bearing blocks each having an arcuate surface for mating with the arcuate surface of a corresponding one of the first and second bearings, and at least one hole therethrough. One of the bearing blocks abuts the actuator mounting surface. The spring mount further comprises at least one fastener having a shaft extending through the at least one hole of each of the first and second bearings and bearing blocks and a corresponding at least one hole in the spring.

Abstract: A weigh feeding system using a stochastic controller wherein the weight of material is sensed, and an estimate of the mass flow state of the material being discharged is created by use of a Kalman filter process. Plant noise processes and measurement noise processes, which affect the measured weight signal, are modeled as stochastic processes and are used, in combination with the sensed weight signal, to calculate the estimated mass flow state. The noise model is modified to account for disturbances. The estimated mass flow state signal is used to calculate a motor feedback signal which, in turn, is used to control the speed of the discharge apparatus. In this manner, the mass flow of the material actually being discharged is driven to a desired mass flow with minimum error variance in the presence of unavoidable plant and measurement noise.

Abstract: The anti-theft product rack continuously monitors the weight of the rack including individual product units. When a weight deviation is detected, it is characterized as either a disturbance or as the removal of one or more product units. An alarm is sounded if the rack is continuously disturbed for a programmable number of continuous weight sensing cycles, or if a programmable number of disturbances occur during a programmable period of time. In addition, an alarm is sounded if the number of product units detected as being removed at one time exceeds a programmable limit. Finally, if the number of detected product units removed exceeds a programmable number during a programmable period of time, an alarm is sounded. The product display rack presents no physical barriers to product removal and requires no intervention of sales personnel for product removal.

Abstract: Mechanical resonance of the vibratory feeder is maintained by minimizing a phase angle difference between substantially sinusoidal drive voltage and current wave forms. The mass flow rate of material being fed is controlled by controlling the electrical power applied to the vibratory feeder compared with a desired electrical power computed from a desired flow rate. The preferred embodiment includes synthesized drive wave forms which are variable in frequency and amplitude in order to maintain the vibratory feeder in mechanical resonance at the desired flow rate. Resonant operation and accurate material flow are accomplished without use of electromechanical vibration sensors and control is accomplished using the magnitude and phase relationships between the applied voltage and current drive wave forms.

Abstract: A weigh feeding system using a stochastic controller wherein the weight of material is sensed, and an estimate of the mass flow state of the material being discharged is created by use of a Kalman filter process. Plant noise processes and measurement noise processes, which affect the measured weight signal, are modeled as stochastic processes and are used, in combination with the sensed weight signal, to calculate the estimated mass flow state. The noise model is modified to account for severe disturbances. The estimated mass flow state signal is used to calculate a motor feedback signal which, in turn, is used to control the speed of the discharge apparatus. In this manner, the mass flow of the material actually being discharged is driven to a desired mass flow with minimum error variance in the presence of unavoidable plant and measurement noise.

Abstract: A weight transducer including an extruded housing having upper and lower inner surfaces. Affixed to the upper inner surface is a hall effect magnetic field sensor, and affixed to the lower inner surface is a pair of magnetic field generating magnets. The magnets are arranged with magnetic poles of opposite polarity located adjacent one another. The hall effect sensor senses changes in the magnetic field generated by the pair of magnets due to relative movement between the upper and lower inner surfaces with application of weight to the housing. The voltage output of the hall effect sensor is converted to a signal having a frequency which varies in proportion to the weight applied to the housing. The hall effect weight transducer provides a very rugged and relatively inexpensive yet highly accurate weight transducer.

Abstract: A vibratory material feeder including a vibrating gate, particularly suited for feeding fibrous materials. The invention includes a vibrating material feed tray having a section providing a tapered smooth transition from vertical to horizontal for material being fed, and a section including a vibrating gate. The vibrating gate is connected to a vibrating gate support member which is connected, by rotatable supports, to first and second relatively movable portions of the vibratory material feeder. As the material tray vibrates, the vibrating gate support member causes the vibrating gate to move with motion opposite to that of the vibrating tray, and with greater magnitude. The smooth transition from vertical to horizontal, combined with the synchronized motion of the vibrating gate, promotes uniform material flow and prevents material agglomeration, particularly for fibrous materials.

Abstract: A control for loss-in-weight feeders which decreases flow error during refill of the feeder hopper. The weight range (empty to full capacity) of the hopper is divided into weight increments. Samples are taken of the hopper weight during discharge and refill, and each sample is assigned to a weight increment. During discharge, a scale factor related to the density of material in the hopper is computed, assigned to a weight increment and stored in memory; and the hopper feed screw is driven at a speed proportional to the computed scale factor. During refill, the stored scale factors are retrieved from memory and the hopper feed screw is driven at a speed proportional to the stored scale factors; but no additional scale factors are calculated.

Abstract: A loss-in-weight gravimetric feeding system is disclosed which includes a prefeeder for receiving and discharging material and at least first and second feeders for receiving material from the prefeeder and discharging the received material to a common collector. The system includes a device for alternately diverting material discharged from the prefeeder to the first and second feeders, circuits for generating a first and second weight signal representative of the weight of material in the first and second feeders respectively, and structure for generating a reference signal representative of a desired mass flow rate of material from a feeder. The system further includes a circuit for alternately comparing the reference signal to the first and second weight signals in synchronism with the diverting device for controlling each of the feeders based on the comparison between the reference signal and the weight signal associated with the feeder.

Abstract: A control for loss-in-weight feeders which decreases flow error during refill of the feeder hopper. The weight range (empty to full capacity) of the hopper is divided into weight increments. Samples are taken of the hopper weight during discharge and refill, and each sample is assigned to a weight increment. During discharge, a scale factor related to the density of material in the hopper is computed, assigned to a weight increment and stored in memory; and the hopper feed screw is driven at a speed proportional to the computed scale factor. During refill, the stored scale factors are retrieved from memory and the hopper feed screw is driven at a speed proportional to the stored scale factors; but no additional scale factors are calculated.

Abstract: An electronic weighing apparatus and method is disclosed which enables the counting of an unknown quantity of items or samples such as currency, coupons, coins or similar items of a nominally uniform weight. The apparatus includes an electronic scale which provides a signal representative of the weight of an unknown quantity of items, a microprocessor which stores a representative unit weight of the items being counted and calculates an item count, and a display for providing an output representing the running count or other value representative of the items being weighed. An accurate count of the items is obtained by placing items on or removing items from the scale in incremental groups such that the net weight of any incremental group of items must have a stable net weight equal to or below a predetermined threshold weight before the count is made.

Abstract: A volumetric screw feeder is interchangeably convertible from a twin screw feeder to a single screw feeder without modification of the gearing or drive means. The change from twin screw feeder to single screw feeder is made by interchanging the screws and the feeder hopper. Moreover, the drive shafts for all of the screws are brought out through a unitary seal.

Abstract: A digital weigh feeder includes a conveyor belt for transporting material thereon. The conveyor belt has an average tare weight. A digital weight transmitter provides at least first and second outputs having first and second frequencies respectively. The ratio of the first and second frequencies is indicative of the weight of material on the belt. A weight processor digitally computes a scaled ratio of the first and second frequencies. An auto tare circuit digitally computes the average tare weight of the conveyor belt. The computed average tare weight is substracted from the computed scaled ratio of the first and second frequencies to obtain a reading of the actual weight of material on the belt.

Abstract: The throughput of a conveyor belt is controlled by a motor whose speed is established by the instantaneous state of an up/down counter. The counter is incremented upwardly by setpoint pulses representative of the desired mass flow rate, and downwardly by feedback pulses from a rate multiplier representative of the actual mass flow rate. When the actual mass flow rate is equal to the setpoint flow rate, the average number of setpoint pulses will equal the average number of feedback pulses with the result that the state of the counter will be stable with time. Speed control means for the motor maintains the belt speed at a level dependent upon the state of the counter. A variation between the actual and desired mass flow rates is manifested by a change in the average number of feedback pulses which results in a change in the state of the counter.