Abstract: An apparatus for measuring the weight of items on a conveyor includes a scale that generates a first signal corresponding to the weight of the items. A movable platform transports the items to the scale and generates a second signal corresponding to position of the items in relation to the scale. A dimensioner examines the items and generates a third signal representative of whether the items are singulated or nonsingulated. A processor receives the second and third signals and determines whether to associate the first signal with information stored in memory about a particular item based upon whether the particular item is singulated or nonsingulated.

Abstract: There is disclosed an apparatus and method which is capable of dispensing very small (typically less than 5 mg) quantities of particles to a high accuracy in a repeatable way and without undue wastage. Also, the need for advanced particle formulation is reduced. The apparatus comprises a closed loop control system which uses an electro-mechanical actuator to deliver impact energy to a supply of particles initially held on a sieve in a hopper. The impact energy causes a small number of particles to fall through the sieve and onto a weight measuring balance. The weight obtained is scrutinised by a processor to see if further actuations are required. In preferred embodiments, the energy of actuation is varied in accordance with the rate of dispensation calculated by the processor. Also, a correction amount can be obtained to take account of the fact that the balance can take a considerable amount of time to settle to its final value.

Abstract: A square baler has a baling chamber and a bale chute arranged at the discharge end of the baling chamber. The bale chute comprises a rear portion that is pivotable about a horizontal axis to allow each bale to be lowered onto the ground without the bale toppling onto its end as it leaves the chute. The invention weighs each bale while the whole of its weight is supported by the rear portion of the bale chute.

Abstract: To provide a medicine weighing device which includes not only a weighing function but also an inspection function, which has a compact structure capable of displaying a weighed value and an inspection result on the same screen, and which can execute inspection according to the input state of weighing conditions.

Abstract: A scale and associated methods automatically identify when a food product pricing scale is in an offline condition and changes a color condition on the scale display to alert scale operators of the offline condition.

Abstract: A method for checking capsules comprises in sequence the phases of weighing each empty capsule and associating the related empty weight value with said capsule by applying a related identification code to the capsule; filling the capsules with doses of filling material, preferably pharmaceutical material; weighing each capsule filled with said material to obtain a related weight value of the filled closed capsule and interpreting the identification code carried by said capsule and relating to its empty weight value; and comparing the weight value of the filled capsule with the empty weight value carried by the aforementioned code in order to detect and check the correctness of the dosage of the material inside each capsule.

Abstract: A method for determining the quantity of items in a container is described, where each item has the same nominal weight located between upper and lower weight limits. The method comprises the following steps: (a) attempting to pack a pre-determined quantity, n, of the items to the container, the predetermined quantity, n, being selected such that the product of (n+1) and the lower weight limit exceeds the product of n and the upper weight limit and such that the product of n and the lower weight limit exceeds the product of (n?1) and the upper weight limit; (b) measuring the weight of the actual quantity of items packed in the container in step (a); and, (c) dividing the value of the weight ascertained in step (b) by the nominal weight to determine the actual quantity of items packed in the container in step (a).

Abstract: A device to weigh objects of like nature has at least a first weighing module and a second weighing module. Each weighing module includes a load receiver and a weighing cell connected to each other through a force-transmitting rod. Each weighing cell is arranged in a design space whose dimensions in a plane that extends orthogonal to the direction of the load is delimited by the design spaces of adjacent weighing cells.

Abstract: A system and method of calculating chemical usage during a refilling of a supply tank, which includes the steps of providing a chemical system having a first supply tank of known capacity, wherein the tank is mounted upon an electronic scale. The scale is capable of generating a series of signals related to the weight of the tank when empty and at various levels of fill. A system controller receives a series of signals from the scale relating to the weight of the tank when empty and at various levels of fill. The first supply tank is filled from a source of chemical feed and the fill time for the filling of the first supply tank is obtained. The system controller inputs the series of signals from the scale relating to the weight of the tank when empty and at various levels of fill and calculates a usage during refilling based on a feed rate times the fill time.

Abstract: Load-bearing devices, each including an overload indicator of the present invention interconnecting load bearing connectors, preferably elongated load bearing connectors are provided. In preferred embodiments, the load bearing connectors are chains, ropes, wire ropes, cables, straps and the like, preferably chain. The wire form overload indicator preferably includes a modified wire form link, preferably either a modified welded link or a modified quick link, generally having a first thickness and first and second elongated sides. The modified link preferably includes two elongated sides, one of which preferably has a portion having a diminished thickness narrower than the first thickness. The diminished thickness preferably has a generally predetermined load bearing capacity or capability and is calibrated to reduce the load bearing capacity or capability of the overload indicator.

Abstract: A method of determining the mass of a mail piece using a load cell. A mail piece whose mass is to be determined is transported across a platform without stopping or slowing the mail piece. A load cell measures the horizontal force applied to the load cell by the transported mail piece. This horizontal force, along with the acceleration of the mail piece, allows a determination of the mass of the mail piece.

Abstract: Method of measuring the weight of bulk liquid material within a container of a tractor-trailer combination in which air bag pressure of a pneumatic suspension system is sensed and correlated with the weight of the bulk liquid material within the container. In accordance with the method, the tractor engine is turned off and supplemental pressurized air is introduced into a pneumatic circuit feeding compressed air to the air bags and while not applying the brakes of the trailer.

Abstract: A device to weigh substantially uniform weighing objects has a plurality of weighing modules and an equal number of load carriers that have central lengthwise axes extending in the direction of the load. Each of the load carriers is connected, respectively, to one of the weighing modules through a force-transmitting rod, and the load carriers are disposed in a given spatial or two-dimensional arrangement in which the distances between neighboring central lengthwise axes are smaller than the largest lengthwise extension of the respective weighing modules.

Abstract: A system and method for fast weighing of items such as mailpieces. The system includes a scale system having a platform connected to a load cell that provides an output signal to an analog-to-digital converter. The resulting digital output signal is processed by a low pass filter and analyzed by a microprocessor to determine weights of items on the platform. The microprocessor also determines postage amounts of items on the platform. The microprocessor also determines postage amounts as functions of the weights and outputs these postage amounts to a postage meter. The microprocessor determines the weights as the median of the peak to valley difference of the digital output signal when the digital output signal peak to valley difference is less than a predetermined value. The microprocessor identifies peaks and valleys of the digital output signal by determining when the derivative of the signal changes sign.

Abstract: A method for weighing a crop is disclosed. The method includes (a) loading a crop into a container using a crop transport apparatus, (b) temporarily stopping the crop transport apparatus from loading the crop into the container, (c) weighing the crop using the container, (d) unloading the weighed crop from the container by automatically manipulating the container, and (e) repeating steps (a)–(d).

Abstract: The present invention is directed to an apparatus and method for measuring the weight of material such as rock, earth, wood, pulp, grain, gravel, sand, ore, cement etc. being processed or moved by an apparatus such as a conveyor, apron conveyor or bucket elevator driven by an electrical motor. The apparatus measures the electrical energy consumed by the motor powering the apparatus during operation of the apparatus and uses a calibration formula derived from an average of no-load readings plus up to 2.0 standard deviations for converting the power consumption of the motor to tonnage per hour of raw material processed by the apparatus. A continual record is kept of all “No-load” and “start-up load” time during the recording process and these figures are totalized along with tonnage for the recording period.

Abstract: An apparatus is provided for measuring the weight force of a bale in a baler wherein the bale moves between a first position, within the baling chamber, and a second position, within a wrapping apparatus carried by the baler chassis. A measurement device, which is connected to a data processing device, is provided, for measuring a measurement parameter influenced by the weight force of said bale in each of said first and second positions and developing a signal representative of the weight of the bale at those positions. The processing device is set up to calculate the weight force of the bale taking into account a first signal output from the measurement device when the bale is in the first position and a second signal output from the measurement device when the bale is in the second position.

Abstract: The mass measurement system includes a linear acceleration motion unit that is a linear motion driving source, a first load cell fastened to the linear acceleration motion unit to measure an inertial force of a sample caused by linearly accelerated motion of the 10 linear acceleration motion unit, a second load cell fastened to the linear acceleration motion unit while being spaced apart from the first load cell by a predetermined distance, the second load cell measuring an inertial force of a standard sample having a known standard mass caused by the linearly accelerated motion of the linear acceleration motion unit, and a main control unit for calculating and outputting mass of the sample through an arithmetic operation based on the inertial forces, measured by the first and second load cells, and the standard mass, and controlling an entire operation of the system.

Abstract: A weighing module comprising a weighing platform incorporating a weighing cell and a motorized drive belt for transporting a mail item from one side to the other of the weighing platform, means for sensing the format of said mail item and processing means for calculating the weight of said mail item within a particular range of weights obtained beforehand from said format.

Abstract: An apparatus for weighing materials online is disclosed, which belongs to an art of online weighing of material. The apparatus comprises: a light-emitting unit, emitting light beams irradiating on the surface of materials transported on a belt to form a bright projection which has the same shape as that of a upper contour of a cross-section of the material; and a CCD camera for continuously picking up images of the bright projection on the upper contour of the cross-section of the material; and an image capture unit, connected to the CCD camera for continuously capturing the images; and a central processing unit, connected to the image capture unit for processing the images captured by the image capture unit to compute a weight of the material. The present invention has many advantages, such as, high precision, good reliability and stability, which applies to the belt without a constant speed and a condition that a bulk shape and the bulk density of the material change largely.

Abstract: A method (10) for reducing or eliminating the effects of proximate samples on the NMR measurement of the mass of a test sample in a NMR check weighing system (24) for samples on a production line. The test sample is in a container (22) on a production line with the plurality of proximate samples each also in a container (22) on the production line. Method (10) includes determining cross coupling weighing factors for a plurality of samples in proximity to the test sample, magnetic resonance measuring of the test sample and proximate samples, the step of magnetic resonance measuring of the test sample and proximate samples providing data representative of each measurement; and applying weighing factors to the data representative of each measurement compensating for the proximate sample effects.

Abstract: A load-bearing device including an overload indicator and a wire form overload indicator are provided for interconnection of load bearing connectors, preferably elongated load bearing connectors, for bearing a load. In preferred embodiments, the load bearing connectors are chains, ropes, wire ropes, cables, straps and the like, preferably chain. The wire form overload indicator preferably includes a wire form quick-link having a first thickness, and first and second elongated sides. The first elongated side preferably includes an interconnectable gap through which connection loops of the load bearing connectors can pass when the interconnectable gap is unconnected. The interconnectable gap includes a connection end and a connectable end, the connecting end having a connector capable of connecting the connecting end to the connectable end to close the gap. The second elongated side preferably has a portion having a diminished thickness as compared to the first thickness.

Abstract: Arrangement and method for determining weight of an occupying item in a seat including one or more weight sensors arranged to obtain a measurement of the force applied to the seat, a forcing function determination arrangement for measuring a forcing function of the seat and a processor coupled to the weight sensor(s) and forcing function determination arrangement for receiving the measurement of the force applied to the weight sensor(s) and the measurement of the forcing function from the forcing function measurement system and determining the weight of the occupying item based thereon. The forcing function determination arrangement may include an accelerometer and measures effects on the seat caused by load of a seatbelt associated with the seat and/or effects on the seat of road roughness, steering maneuvers, and a vehicle suspension system.

Abstract: A scale including an event data discrimination and collection system for continuously monitoring a weight of an infant placed on the scale platen, which may be configured as a bed. Load cells are used to continuously monitor infant weight from time placed on the scale platen, so that sudden apparent weight spikes sensed by the load cells but attributable to events involved in patient care may be discarded as artifact, while gradual weight changes reflective of infant physiology are accumulated by the scale controller and used to provide a current weight for the infant.

Abstract: A substance mass measuring system is applied to a microgravitational rotating apparatus vibration control system to easily measure the mass of an object placed in an experimental box. Recess portions (10a, 10b) are provided in a casing (10). Both ends of a rotary shaft (30) are supported by bearings (11, 12) in the recess portions (10a, 10b). A lower end of the rotary shaft (30) is connected to a motor (13). Four arms (24 to 27) arranged horizontally in the direction of X and Y axes, are at their one ends fixed to the rotary shaft (30) and at the other ends fitted with experimental boxes (20 to 23). Experimental objects are placed in the boxes (20 to 23) and rotated for experiments in space. Vibration of the rotary shaft (30) and the boxes (20 to 23) is absorbed by the bearings (11, 12). Side plates (1a to 1d), acceleration sensors (2a to 2d) and distance sensors (3a to 3d) are arranged in the boxes (20 to 23).

Abstract: This invention relates to a method and apparatus for mass and/or volume measurements of manufactured articles. More particularly, this invention relates to a method and apparatus for mass and/or volume measurements that can be performed on-line in a part manufacturing process. On-line measurement of the mass or volume of material contained in a specific region of interest of the manufactured items is performed 100% on-line. Real-time process control information is based on real-time measurement of the mass or volume of material contained in a specific region of interest of a manufactured item. Automated quality control inspection for manufactured articles is based on real-time measurement of the mass or volume of material contained in a specific region of interest of manufactured items.

Abstract: A method is provided for weighing a series of mail pieces such as letters, flats or a mixture thereof, that are being conveyed through a weighing module. Each mail piece has a length which falls within a range bounded by a maximum length and a minimum length. The mail pieces are conveyed through the weighing module at a substantially constant speed while maintaining a minimum gap between successive mail pieces as the mail pieces pass through the weighing module. The weight of each mail piece is measured during a measurement time when that mail piece is the only mail piece moving on the scale. The scale is sized so that measurement times for mail pieces between the maximum and minimum lengths will vary.

Abstract: A system and method for weighing of items such as mailpieces in the presence of external vibration such as ground noise. The system includes a scale system having a platform connected to a load cell, which provides an output signal to an analog-to-digital converter. The resulting digital output signal is processed by a low pass filter and analyzed by a microprocessor to determine weights of items on the platform. The microprocessor also determines postage amounts as functions of the weights and outputs these postage amounts to a postage meter. The microprocessor determines the weights as the median of the peak to valley difference of the digital output signal when the digital output signal peak to valley difference is less than a predetermined value. The microprocessor identifies peaks and valleys of the digital output signal by determining when the derivative of the signal changes sign.

Abstract: A load-bearing device including an overload indicator and a wire form overload indicator are provided for interconnection of load bearing connectors, preferably elongated load bearing connectors, for bearing a load. In preferred embodiments, the load bearing connectors are chains, ropes, wire ropes, cables, straps and the like, preferably chain. The wire form overload indicator preferably includes a wire form quick-link having a first thickness, and first and second elongated sides. The first elongated side preferably includes an interconnectable gap through which connection loops of the load bearing connectors can pass when the interconnectable gap is unconnected. The interconnectable gap includes a connection end and a connectable end, the connecting end having a connector capable of connecting the connecting end to the connectable end to close the gap. The second elongated side preferably has a portion having a diminished thickness as compared to the first thickness.

Abstract: A weighing system and a postage metering system including such a weighing system. The weighing system includes a transport assembly having a transport for receiving and outputting mail pieces to be weighed and for supporting mail pieces while they are weighed, and a feeder for successively feeding the mail pieces to the transport. A transducer supports the transport and generates and output representative of the load presented by pairs of mail pieces on the transport. After a current item and a previous item are weighed together on the transport, the transport is energized to output the previous item and replace the previous item with the current item, and the feeder is energized to input a next item to the transport as a new current item.

Abstract: A method and an apparatus for estimating the weight of horses. To estimate the weight of a horse, a girth, a length, and a height of the horse are measured. The measurements can be taken with commercially available measurement tapes, for example. The weight of the horse is then estimated based on the girth, the length and the height of the horse. The present invention will be utilized in the care and management of horses thereby resulting in advanced equine health and nutrition, better training results, and improved overall health monitoring.

Abstract: A system for check weighing the content of a blister strip which includes a guide adapted to receive a blister strip comprised of at least one blister, a punch aligned with the guide for receiving the at least one blister, an actuator engaged with the punch for driving the punch toward the blister strip, whereby the blister is punched from the blister strip, and a balance adapted to receive the punched blister for weighing the punched blister and generating a weight signal after subtracting a predetermined value representing the weight of an empty blister. An alternative method of determining the content of a blister strip comprises reflecting a beam of energy off of a blister strip and determining the height of the blister from the reflected energy. The measured height is compared to a predetermined height to derive the amount of powder contained therein.

Abstract: A vibrating tray scale capable of detecting small amounts of loose particulate matter contained within a mail piece is disclosed. The scale is provided with a clamping device having a plurality of clamping positions. Utilizing different clamping positions, the mass of a mail piece is determined two times, one not including the mass of any loose particulate matter within the mail piece and one including the mass of any loose particulate matter within the mail piece. A determination of whether or not the mail piece contains any loose particulate matter can be made based on a comparison of the results for the two mass determinations.

Abstract: A check weighing system is provided which can check weigh samples (1) on a production line. The check weighing system comprises a magnet (13) for creating a static magnetic field over an interrogation zone for creating a net magnetisation within a sample (1) located within the interrogation zone and an RF coil for applying an alternating magnetic field over the interrogation zone for causing excitation of the sample (1) within the interrogation zone according to the principles of NMR. The check weighing system also comprises a sensor for sensing the energy emitted as the sample relaxes back to an equilibrium state after excitation as the samples pass through the interrogation zone on a conveyor belt (9) forming part of the production line.

Abstract: A method for weighing mailpieces while in motion in a mailpiece weighing system. The weigh pan in the mailpiece horizontal transport path generates a signal corresponding to a weight of the moving mailpiece, and the system controller compares the weight of the moving mailpiece to a postal weight break to determine if the postal weight break is within the margin of error of the weighing mechanism. If the postal weight break is within the margin of error of the weighing mechanism, the system controller stops transport of the moving mailpiece and reweighs the mailpiece.

Abstract: A system for accepting and storing items for subsequent pickup by a commercial carrier includes a storage area which is defined by an outer housing, and a customer interface area that includes a weighing unit and a unit, such as a magnetic card reader, for accepting payment from a customer. The system may also include a control system that accepts address information from the customer through a key pad, and then instructs a printer to print an address label for the item. The system includes safeguards which prevent unauthorized access to the storage area, and will not provide a receipt to the customer until internal sensors verify deposit of the item. A manifest printer may also be provided for the benefit of the commercial carriers who service the system, to print out a summary of the transactions that pertain to each carrier. Alternatively, no storage area is provided.

Abstract: A method of controlling the evaporation of liquid in samples in an evaporating centrifuge, by monitoring the centrifugal force exerted on a sample holder containing a liquid sample having solid material dissolved or otherwise mixed therein. The centrifugal force is determined using a load cell, a strain gauge or, where relative movement between sample holder and rotor is permitted albeit with resilient restraint, the centrifugal force signal may be generated by a position sensing transducer. The speed of rotation is sensed by a further transducer and both force and speed signals are conveyed to a computer programmed to generate a process control signal for controlling the evaporation process therefrom. A preferred method of control involves determining the rate of change of weight with time and terminating the evaporation process when the rate of change drops to zero.

Abstract: A method is provided for weighing a series of mail pieces such as letters, flats or a mixture thereof, that are being conveyed through a weighing module. Each mail piece has a length which falls within a range bounded by a maximum length and a minimum length. The mail pieces are conveyed through the weighing module at a substantially constant speed while maintaining a minimum gap between successive mail pieces as the mail pieces pass through the weighing module. The weight of each mail piece is measured during a measurement time when that mail piece is the only mail piece moving on the scale. The scale is sized so that measurement times for mail pieces between the maximum and minimum lengths will vary.

Abstract: The invention relates to an instrument and method for measuring minute quantities of weight, including a pan for holding a sample to be weighed, a chamber for forming an enclosure about the pan, and a hang-down wire coupled to the pan for suspending the pan within the chamber. The pan has a volume less than 0.020 cm3 and the hang-down wire has a volume less than 0.01 cm3. The invention may also include a carrier gas, placed within the chamber, having a generally consistent density over changes in temperature.

Abstract: Arrangement and method for determining weight of an occupying item in a seat including one or more weight sensors arranged to obtain a measurement of the force applied to the seat, a forcing function determination arrangement for measuring a forcing function of the seat and a processor coupled to the weight sensor(s) and forcing function determination arrangement for receiving the measurement of the force applied to the weight sensor(s) and the measurement of the forcing function from the forcing function measurement system and determining the weight of the occupying item based thereon. The forcing function determination arrangement may include an accelerometer and measures effects on the seat caused by load of a seatbelt associated with the seat and/or effects on the seat of road roughness, steering maneuvers, and a vehicle suspension system.

Abstract: A body weigh scale that displays a user's weight in a gravity system other than where the scale is being used, such as a planet, the sun, the moon, or another celestial body. The body weigh scale includes a conversion component that converts the user's weight to the other gravity system. In one embodiment, the scale utilizes a mechanical weighing mechanism, having an analog display, and also has a digital display, where weight information is generated, for example, by a pulse counter. The user's weight may be simultaneously displayed both in the “home” gravity system where the scale is used (e.g., the earth), and another, “away” gravity system (e.g., the sun). The display of the home weight may be via an analog dial, and the display of the away weight may be via a digital display such as an LCD.

Abstract: The present automated vehicle regulation compliance enforcing system is comprised of an on-board monitoring system for being installed on a heavy truck, and an interrogation system for being installed in enforcement vehicles and inspection stations. The monitoring system is comprised of a processor connected to speed and weigh sensors installed in the truck and trailers. The processor is arranged to monitor various operating parameters of the truck, such as loading, load distribution, speed, driver maintenance information, driving time, and mileage. The processor is also connected to an interface which enables the truck operator to input driver and vehicle information, and a transceiver for communicating with the interrogation system. The interrogation system is comprised of a processor connected to a transceiver, and arranged to interrogate the monitoring system to download data.

Abstract: This invention relates to a media weight sensor of the type that includes transducers located both above and below the media, whose weight is to be determined. One transducer is driven with an AC signal of a given frequency. The acoustic energy passing through the media reaches the other transducer, thereby generating an AC voltage signal. The level of the signal is proportional to the amount of acoustic energy reaching this transducer. The heavier the media, the more energy is blocked or absorbed and the lower is the level of the signal received by the second transducer.

Abstract: A weight scale having an operational weighing range, comprising an overall response characteristic having at least first, second and third discrete stages over the operational weighing range. The first, second and third stages are defined by first, second and third predetermined response characteristics, respectively. The weight scale further comprises first, second and third scale arrangements or mechanisms which establish the first, second and third response characteristics, respectively, of the three stages.

Abstract: An electronic balance is provided in which influences due to a four-corner error can be eliminated from an indicated value of weighing without strictly conducting mechanical adjustment, so that correct indication can be always performed.

Abstract: A unique method and apparatus for making a load cell provides faster assembly throughput and a manufacturing cost reduction. The method and apparatus includes adhering a sensor to a metal surface and clamping the sensor to the metal surface with heated clamps. Heat is applied directly through the clamps to heat the interface between the sensor and metal surface for a predetermined amount of time to form a secure bond.

Abstract: An apparatus and method for measuring the weight of a moving object is disclosed. In one embodiment, the apparatus includes a platform for supporting the moving object to be weighed, means for permitting the object to move smoothly over the platform, a weight sensor for measuring a force applied to the platform by the moving object and generating a weight sample that reflects the measured force value, a detection sensor that generates a signal upon detecting the moving object on the platform, a processor having a memory, which processor receives samples from the weight sensor and stores weight values based on the samples; and means for calculating the weight of the object using a succession of the stored values when the detection sensor generates its signal.

Abstract: A weight and form sensing apparatus according to the present invention provides weight sensors on a base, in matrix pattern for instance. Each weight sensor has a load receiving portion on a top. Weight and form can be sensed by single weight and form sensing apparatus according to the present invention. That is, output values of the weight sensors are summed, so that an article put on the weight sensors can be detected. Also, the existence of the load on each weight sensor is determined based on output signal of each weight sensor, so that the bottom form and size of the article can be identified. The weight and form sensing apparatus according to the present invention can be preferably arranged into a feeding stream of the article because an arrangement of the sensors for identifying the form and size of the article does not interfere an arrangement of the feeding mechanism for the article.

Abstract: An ultrasonic distance measuring system for monitoring railroad car loads. The system includes an ultrasonic transducer, a pulse generation and detection circuit and a measurement circuit. The transducer produces a transmitted ultrasonic pulse beam to be directed at a load in a railroad car and receives a return pulse beam from the load. The pulse generation and detection circuit is coupled to the transducer and causes the transducer to produce the transmitted pulse beam. A return pulse beam is detected by the pulse generation and detection circuit. The measurement circuit is coupled to the pulse generation and detection circuit and generates a measurement signal representative of the load as a function of the time delay between the transmitted and return pulse beams.

Abstract: The scales include a tray (1) placed on a base (3) and lifted by an air cushion, with no mechanical connection with the base (3). The weight of an object (21) laid on the tray (1) varies the air cushion pressure, and the measurement of this pressure by an external sensor (19) is straightforward and gives the weight of the object (21) once a law of correlation has been determined. Lateral pipes enable gas to be blown against a flange (2) of the tray (1) and thus horizontal displacements of the tray and friction to be avoided. Several vertical pipes are generally provided so as to reduce tray (1) tipping after the object (21) has been thrown off centre, the weight being then given by the sum of the measurements of each vertical pipe.