Strain Gauge Patents (Class 177/211)
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Patent number: 5780777Abstract: In order, in a weighing device, in particular for use in high-resolution scales, comprising an elastically deformable force transducer, a sensor arrangement for converting the deformation of the force transducer caused on account of a force F acting on the force input section of the force transducer into an electrical weighing signal and a processing unit for calculating a weighing signal corrected by the hysteresis error of the force transducer, to be able to realize a correction of the hysteresis error even with the short-term load variations occurring in practice in high-resolution scales at an acceptable cost, it is suggested that the sensor arrangement comprise a first testing unit for the high-resolution determination of the weighing signal "S" and a second testing unit for the determination of the elastic deformation of the force transducer in small time increments (high time resolution), wherein the processing unit corrects the high-resolution weighing signal of the first testing unit by the hysteresiType: GrantFiled: March 6, 1997Date of Patent: July 14, 1998Assignee: Bizerba GmbH & Co. KGInventor: Klaus Peter Selig
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Patent number: 5756943Abstract: A load cell for use in detecting a load imposed thereon which includes a body (30) in which strain is induced in proportion to the imposed load, and a strain sensor (40) for detecting the strain induced in the body (30). The body (30) is a plate member having a longitudinal axis (X) and the strain sensor (40) is mounted on the body (30). The body (30) has an opening (31) defined therein at a location intermediate of the length of the body (30) so as to define a fixed rigid body forming region (70) at one end thereof, a movable rigid body forming region (71) at the opposite end thereof opposite to the fixed rigid body forming region (70) in the longitudinal direction (X), and side connecting strips (30b, 30b) spaced by the opening (31) from each other in a widthwise direction (Y) of the opening (31) and connecting the fixed rigid body forming region (70) and the movable rigid body forming region (71) together.Type: GrantFiled: May 31, 1996Date of Patent: May 26, 1998Assignee: Ishida Co., Ltd.Inventors: Kazufumi Naito, Michito Utsunomiya, Hiroyuki Konishi, Shotaro Tamai
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Patent number: 5752498Abstract: A humidifier for use with a hot air furnace has an upper and lower housing removably connected to one another. The upper housing has a heating element and sensor, water refill inlet, and a control circuit connected to the heat sensor and inlet. The lower housing contains a water vessel and a water level sensor secured the lower housing to receive the water vessel. The water sensor registers the minimum and maximum water weight and is connected to the control circuit. A bacteria resistant, semi-flexible removable liner fits within the vessel for the removal of built up mineral residue. Preferably the water sensor is an elliptical beam load cell with an open center surrounded by a rim and a pair of tab ends opposite one another. At least one bridge is machined within the rim to increase sensitivity. A strain gage registers strain changes and an electronic connector transfers the changes to the control circuit where they are converted to the current weight.Type: GrantFiled: January 24, 1996Date of Patent: May 19, 1998Inventors: Jared L. Lake, Brad C. Koelblinger
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Patent number: 5742011Abstract: Two thin walled strain generating areas are provided in each of upper and lower two beams provided between a fixed rigid body and a movable rigid body. The strain generating area of the upper beam is adapted to have a convex-shaped cross section such that the neutral plane which develops no strain in response to a bending moment acting on the strain generating area is spaced from the top surface by a distance unequal to that from the bottom surface. In addition, a strain detecting element is provided on the top surface which is more remote from the neutral plane than the bottom surface.Type: GrantFiled: October 26, 1995Date of Patent: April 21, 1998Assignee: Ishida Co., Ltd.Inventors: Kenji Imai, Yoshinobu Shimomae, Yoshiaki Shinada
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Patent number: 5734110Abstract: A bolt-on strain sensor includes an L-shaped sensor body having a mounting hole formed at the end of each leg of the L-shaped body and a mounting hole formed at the intersection of the legs. A first strain sensing structure is formed in the sensor body between two of the mounting holes and a second strain sensing structure is formed in the sensor body between the other two mounting holes. The strain sensing structure is preferably a strain gauge instrumented measurement beam connected to the sensor body on opposite sides of the strain sensing region by spaced apart interconnecting members. A printed circuit board on which a plurality of electrical components are mounted is secured to the sensor body with a suitable fastener. A cover is then placed over the sensor body and printed circuit board.Type: GrantFiled: October 11, 1996Date of Patent: March 31, 1998Assignee: Kistler-Morse CorporationInventor: Alfred J. Kosmal
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Patent number: 5723826Abstract: A load cell unit in accordance with the present invention comprises a load cell and a wiring board. The load cell comprises a flexible member provided with a through hole formed between the fixed end and the moving end thereof so as to form four flexible portions, and strain gages attached to the flexible portions, respectively. The wiring board is provided with a circuit connected to the strain gages of the load cell so as to form a bridge circuit including the strain gages, and a processing circuit connected to the bridge circuit. The wiring board has a first major surface mounted with at least film capacitors among the circuit elements of the processing circuit, and a second major surface.Type: GrantFiled: July 3, 1995Date of Patent: March 3, 1998Assignee: Kabushiki Kaisha TECInventors: Tohru Kitagawa, Yoshihisa Nishiyama, Shuji Takabayashi
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Patent number: 5717166Abstract: The invention is a system for combining the outputs of two transducers to provide a continuous reading over the combined ranges of the two transducers. The system applies an A.C. signal to the appropriate transducer; the steering for the excitation is controlled by the system microprocessor. The transducers are connected in series mechanically such that the low-range transducer is mechanically stopped before it is overloaded. The outputs of the transducers are connected in parallel and applied to the pre-amp which amplifies the A.C. error signal. The signal from the pre-amp is then applied to the analog-to-digital converter (ADC) for conversion. The ADC converts the pre-amp signal which is then sent to the system microprocessor over a serial link. The system microprocessor then applies the appropriate weighing algorithms to the data and then conveys that information to the parent system.Type: GrantFiled: October 24, 1994Date of Patent: February 10, 1998Assignee: Pitney Bowes Inc.Inventor: Paul C. Talmadge
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Patent number: 5714695Abstract: A helical load cell is disclosed which is capable of accurately measuring axially applied forces, whether the force is applied axially within the diameter of the helical coil or outside of the coil diameter. A pair of strain gage modules are disposed on diametrically opposed surfaces of the coil. Each module includes a pair of transducer elements disposed orthogonally with respect to each other and at forty-five degrees relative to a neutral axis of the coil. The modules are coupled in an additive bridge circuit arrangement. In one embodiment, the modules are disposed along the outside diameter of the coil. In another embodiment, the modules are disposed along the inside diameter of the coil. In yet another embodiment, the modules are dispose on the upper or lower surface of the coil. In yet another embodiment, a second pair of strain gage modules is provided and coupled in a subtractive bridge circuit. The second pair of modules provides information as to the location of the applied load.Type: GrantFiled: February 4, 1997Date of Patent: February 3, 1998Assignee: Sentek ProductsInventor: Robert W. Bruns
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Patent number: 5708236Abstract: A weighing scale comprising a housing having an upper platform for receiving a load, and a base; a lever assembly comprising a plurality of levers, each of which is in operative contact with the upper platform and supported by a post element mounted on the base. A cantilever beam is mounted on the base and positioned between the lever assembly and the base. A weight-transmitting pin is provided for supporting the lever assembly and acting on the cantilever beam for transmitting the load from the intermediate cover to the cantilever beam through the lever assembly. A strain gauge element is fixed on the cantilever beam for converting a strain developed therein into an electrical signal.Type: GrantFiled: June 28, 1995Date of Patent: January 13, 1998Assignee: Enlight CorporationInventors: Gad Shaanan, Walter Francovich, Derek Hunziker
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Patent number: 5670753Abstract: The invention relates to a disc-shaped transducer (10) for a weighing system, comprising surfaces (14) which extend parallel to one another and in a direction of application of a force (F) to be measured, at least one of said surfaces being provided with a sensing element (13) for converting a force-dependent deformation into a useful signal. Transducers (10) of this kind usually exhibit a material-dependent, significant hysteresis effect which adversely affects their calibration possibilities; therefore, the transducer (10) comprises four sub-faces (21) which are formed by a centre line (17) parallel to the direction of application of the force (F) and a centre line (20) which is orthogonal thereto, at least two of said sub-faces which adjoin one another in only one point comprising a respective area of reduced cross-section or reduced thickness, so that the hysteresis can be compensated for.Type: GrantFiled: October 4, 1993Date of Patent: September 23, 1997Assignee: U.S. Philips CorporationInventor: Matthias Krause
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Patent number: 5663531Abstract: An electronic weighing apparatus includes a base which supports a cantilevered elastic member upon which a load platform is mounted. The free end of the elastic member is provided with a first piezoelectric transducer and a second piezoelectric transducer is supported by the base. Each transducer includes a substantially rectangular piezoelectric substrate and a pair of electrodes imprinted on the substrate at one end thereof. The transducers are arranged with their substrates substantially parallel to each other with a small gap between them and with their respective electrodes in relatively opposite positions. The electrodes of the second transducer are coupled to the input of an amplifier and the output of the amplifier is coupled to the electrodes of the first transducer. The resulting circuit is a positive feedback loop with a "delay line" in which a surface acoustic wave in one substrate is effectively induced into the other.Type: GrantFiled: June 12, 1995Date of Patent: September 2, 1997Assignee: Circuits and SystemsInventor: Vyacheslav D. Kats
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Patent number: 5646376Abstract: A portable aircraft weighing scale, comprising:(a) a base having load cell mounting structures;(b) a plurality of shear beam load cells mounted to the base via the mounting structures;(c) a platform for supporting an aircraft wheel or wheel set; and(d) a mechanism for mounting the platform to the load cells.Type: GrantFiled: June 9, 1994Date of Patent: July 8, 1997Assignee: Intercomp CompanyInventors: William Kroll, Mark Browne, Tom Bartsch, Randie Evenson
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Patent number: 5623128Abstract: A digital load cell includes an EEPROM that is permanently attached to the counterforce along with a temperature sensor and a plurality of strain gages. The strain gages are mounted on the counterforce in the electrical configuration of a full wheatstone bridge. The EEPROM and bridge are connected to a flexible circuit that is detachably connectable in electrical communication with circuits including a processor and an analog-to-digital converter, which can be mounted permanently on a local circuit board physically separated from the EEPROM. The local circuit board operates in a manner so that the EEPROM can be programmed to store the calibration/correction factors that are to be applied by the processor to the digital weight signals from the analog-to-digital converter. The local circuit board is associated with, and alternatively can be removably attachable to, the counterforce.Type: GrantFiled: March 1, 1994Date of Patent: April 22, 1997Assignee: Mettler-Toledo, Inc.Inventors: Steven R. Grimm, Richard C. Loshbough
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Patent number: 5606516Abstract: A pressure transducer module includes a plurality of cavities, each cavity in fluid communication with a hydraulic load cell. Each cavity deforms with variations in the pressure of the hydraulic fluid in the cavity. Sensors generate output signals representative of the deformation of the cavities. The sensor output signals are digitized and multiplexed, whereby the transducer module generates a digital output data stream. The pressure transducer module is pre-calibrated for creep, hysteresis, non-linearity and temperature related errors. A computer controller stores the calibration data for the module. The pressure transducer module also includes a temperature sensor. A weighing system includes a weighing platform or structure; at least one pressure transducer module; and hydraulic transducers for measuring the load applied to the weighing platform or structure. A controller receives the outputs of the sensors and applies the calibration data to calculate the weight of the load on the platform.Type: GrantFiled: August 7, 1995Date of Patent: February 25, 1997Assignee: Fairbanks Scales Inc.Inventors: Alec T. Douglas, Harry J. Keen
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Patent number: 5539158Abstract: A load cell for detecting a load imposed thereon and for improving the productivity thereof. The load cell includes a strain inducing device (1) made of metal and including a strain generating area (6) for generating a strain as a function of the load, and a strain sensor (40) including a metal substrate (41) having a strain detecting element (43) formed thereon for detecting the strain generated at the strain generating area (6) of the strain inducing means (1). The strain sensor (40) is mounted on the strain inducing device (1) with the metal substrate (41) welded thereto.Type: GrantFiled: November 15, 1994Date of Patent: July 23, 1996Assignee: Ishida Co., Ltd.Inventors: Michito Utsunomiya, Kazufumi Naito, Hiroyuki Konishi, Shotaro Tamai
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Patent number: 5526702Abstract: The present invention relates to an arrangement of measurement devices on a semitrailer motor vehicle having a tractive unit, a semitrailer unit, and a fifth wheel fastened to the tractive unit. The measuring arrangement includes a support structure for the fifth wheel and measurement devices for measuring forces arising between the semitrailer and the tractive unit attached to the support structure. The measurement devices preferably measure acceleration, tractive or braking forces and/or the weight of the semitrailer.Type: GrantFiled: February 16, 1994Date of Patent: June 18, 1996Assignee: Georg Fischer Verkehrstechnik GmbHInventors: Kurt Schedrat, Lothar Jakob, Dirk Engels
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Patent number: 5515737Abstract: To facilitate the adjustment of the accuracy and servicing maintenance of the electronic weighing apparatus, the weighing apparatus comprises a load cell and a signal processing circuit for processing a load signal from the load cell to provide a weight signal indicative of the load. The load cell includes a strain inducing element capable of producing strains in proportion to the load imposed thereon, and a bridge circuit, having a pair of strain gauges fixed on the stain inducing element and a plurality of resistors. A load signal is taken from a junction between the strain gauges and reference voltage signals are taken from junctions between the resistors. The load signal and the reference voltage signals are supplied to the signal processing circuit.Type: GrantFiled: May 8, 1995Date of Patent: May 14, 1996Assignee: Ishida Co., Ltd.Inventors: Kenji Imai, Kazufumi Naito
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Patent number: 5512713Abstract: A load cell for use in detecting a load imposed thereon which includes a strain inducing unit (1) having a longitudinal axis and including a strain generating area (6) for generating a strain as a function of the load, and a strain sensor (40) including a substrate (41) having a strain detecting element (43) formed thereon for detecting the strain generated at the strain generating area (6) of the strain inducing unit (1). The strain inducing unit (1) includes a fixed rigid body (2), a movable rigid body (3), first and second beams (4) connecting the fixed rigid body (2) and the movable rigid body (3) together, and an intermediate plate structure (30) fixed to and positioned between the fixed and movable rigid bodies (2 and 3). The intermediate plate structure (30) has a cut space (P) defined therein at a location intermediate between the fixed rigid body (2) and the movable rigid body (3).Type: GrantFiled: June 27, 1994Date of Patent: April 30, 1996Assignee: Ishida Co., Ltd.Inventors: Kazufumi Naito, Michito Utsunomiya, Hiroyuki Konishi, Shotaro Tamai
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Patent number: 5510581Abstract: This invention is a mass-produced, flat, multiple-beam load cell for use in weighing devices. This load cell is particularly suited to very low-profile scales incorporating a plurality of load cells. It is made from a flat piece of metal and includes: (1) a load-receiving member having a transverse section integral with a load-receiving tongue symmetrical about a north-south axis of the plate, which reach across an east-west axis of the plate; (2) a clamping member having a transverse section and possibly a pair of clamping tongues which reach across the east-west axis; and (3) two flexure beams connecting the two transverse sections of the metal plate, each beam symmetrical about the east-west axis, and the beams symmetrical about the north-south axis.Type: GrantFiled: May 18, 1994Date of Patent: April 23, 1996Inventor: Shlomo Angel
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Patent number: 5493920Abstract: The present invention relates to an arrangement of measuring devices on a semitrailer motor vehicle having a tractive unit, a semitrailer unit and a fifth wheel fastened to the tractive unit. An intermediate plate is disposed between the fifth wheel, the tractive unit and the semitrailer and is connected to the semitrailer. Measuring devices are disposed on the intermediate plate for measuring acceleration, tractive or braking forces and for measuring the weight of the semitrailer. The measured values are used to influence and improve the driving behavior of the semitrailer motor vehicle.Type: GrantFiled: February 16, 1994Date of Patent: February 27, 1996Assignee: Georg Fischer Verkehrstechnik GmbHInventors: Kurt Schedrat, Lothar Jakob, Dirk Engels
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Patent number: 5440078Abstract: A load cell for scales and the like has an elongated bar having opposite sides, sloped ends and a removable top portion. A pair of load cells are mounted within the housing with each load cell comprising an elongated bar having opposite ends, opposite sides, a center portion, and top and bottom surfaces. The bar has cavity openings extending into the sides thereof adjacent each of the opposite ends. A strain gauge is mounted in each of the cavity openings and is sensitive to deflection of the bar caused by weight exerted on the top surface of the bar. Each of the strain gauges are connected to a visual readout apparatus which collectively reflects the loads imposed upon the bars. A cantilever support element is positioned on the bottom surface of the bars and has a length less than the bars to create a space below the bottom thereof and a support surface upon which the cantilever support bar is positioned to suspend the ends of the bar in cantilever fashion.Type: GrantFiled: July 19, 1993Date of Patent: August 8, 1995Assignee: Schrran Engineering, Inc.Inventor: Daniel D. Schuler
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Patent number: 5425278Abstract: A load cell formed with a single crystal beam and strain gages deposited thereon. The single crystal beam may be advantageously formed from sapphire. The beam is arranged in the load cell with a fixed portion and a free portion to which weight forces may be applied. At least one strain gage is deposited on the beam to provide signals responsive to the applied weight forces. The method for making the load cell includes growing the crystal, depositing a strain sensitive layer on the crystal substrate, foxing the strain sensitive layer into at least one strain sensitive element and attaching a plurality of electrical leads to the strain sensitive elements to form strain gages. A weighing device is formed of a base upon which a plurality of the load beams are arranged for supporting a weigh platform.Type: GrantFiled: September 17, 1993Date of Patent: June 20, 1995Assignee: Pneumatic Scale CorporationInventor: John D. Perkins
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Patent number: 5414225Abstract: A portable weighing device comprising two laterally displaced, electrically connection and rigidly aligned weighing modules is disclosed that permits convenient weighing of the mobility-disabled while occupying a conventional manually-operated wheelchair supported by two front caster wheels and two rear main wheels. The portions of the weight of the wheelchair supported by each wheel is successively summed and the tare is electronically subtracted. The weight of the occupant is then displayed. Accordingly with the weighing device wheelchair users can be conveniently weighted at rehabilitation centers, physician's offices or hospital clinics, or alternatively can weight themselves at their residence. The weighing device can be folded for carriage or storage.Type: GrantFiled: May 7, 1993Date of Patent: May 9, 1995Inventor: Moishe Garfinkle
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Patent number: 5369226Abstract: Load shift compensation of a strain gage load cell is accomplished by connecting a pair of fixed resistors in series across the output of a bridge circuit incorporating the load cell strain gages. The junction point between the series resistors is established at a desired signal level by a digital to analog converter connected thereto or by a voltage divider network so that, in effect, a part of the resistance of the resistors required to achieve load shift compensation is made to shunt a pair of the strain gages in the bridge circuit. The required signal level may be established by positioning weights on the scale platter at different positions parallel to the longitudinal axis of the load cell beam and adjusting the signal level at the junction point between the shunting resistors until a desired degree of compensation is achieved. The digital correction value required at the input of the digital to analog converter to achieve compensation is stored in the memory of the scale computer.Type: GrantFiled: April 29, 1993Date of Patent: November 29, 1994Assignee: Mettler-Toledo, Inc.Inventors: Neil C. Griffen, Richard C. Loshbough
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Patent number: 5338901Abstract: A conveyor belt scale of the weighbridge type is disclosed having a frame mountable above a run of conveyor belt idler, the weighbridge having a pair of weight transfer bars extending from each end of the device to support the entire weight of the weighbridge and conveyor belt, each of the weight transfer bars being cooperatively connected to a load cell apparatus, each pair of load cells at an end of the device is cooperatively connected by a strain gauge disposed to measure deflections of the load cells under the weight and tortional movement of material passing along the conveyor. The apparatus further contains a speed sensor device to measure the speed at which material moves along the conveyor and a programmable computerized integrator apparatus which accepts the information from the strain gauges and from the speed sensor to give a digital readout of an estimated weight and volume of material passing along the weighbridge at any given time.Type: GrantFiled: June 22, 1992Date of Patent: August 16, 1994Assignee: Kaskaskia Valley Scale CompanyInventor: Ron Dietrich
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Patent number: 5327791Abstract: A system for sensing the load on a load supporting beam of a vehicle. The system comprises an elongate sensor beam and means for releasably securing a pair of opposite end sections of the sensor beam to a load supporting beam of a vehicle. The sensor beam is secured to the load supporting beam so that a longitudinal axis of the load sensor beam is aligned with a longitudinal axis of the load supporting beam. A plurality of strain gauges are attached to a central section of the load sensor beam. The strain gauges are connected so that each of them can transmit an output signal processor.Type: GrantFiled: January 16, 1992Date of Patent: July 12, 1994Inventor: Robert R. Walker
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Patent number: 5313022Abstract: A load cell adapted to be positioned between a foundation and each of several support members for a storage vessel. The load cell includes a circular flex plate having a pair of concentric cylindrical members of different diameters secured to opposite surfaces. A mounting pad adapted to be fastened to the foundation is secured to one of the cylindrical members. A mounting plate is secured to the other cylindrical member. The mounting plate has either a single threaded bore or a threaded stud positioned at the common axis of the cylindrical members for securing the mounting plate to a vessel support member. A strain sensor mounted on the flex plate measures the load-induced deflection of the flex plate.Type: GrantFiled: November 12, 1992Date of Patent: May 17, 1994Assignee: Kistler-Morse CorporationInventors: Farid Piroozmandi, Walter P. Kistler
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Patent number: 5294756Abstract: A scale apparatus is provided for weighing material moving on a conveyor belt supported by an idler assembly. The apparatus includes a load cell support and a load cell having a base and a contact portion extending upwardly away from the base. The base of the load cell is configured to bend in response to a vertical force being applied to the contact portion to generate an output signal proportional to the force. The load cell is non-responsive to horizontal forces. The load cell is coupled to the load cell support, and the load cell support is coupled to a conveyor frame to suspend the load cell below the conveyor belt. The apparatus further includes an idler support for supporting the idler assembly. The idler support is coupled to the contact portion of the load cell.Type: GrantFiled: May 5, 1992Date of Patent: March 15, 1994Assignee: Endress+Hauser Inc.Inventors: Jurgen Lauber, Eric Wainwright
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Patent number: 5287757Abstract: A strain-gauge transducer comprises a strain gauge enclosed between pressure members which deform the strain gauge, the strain gauge comprising a plate-shaped substrate provided with strain-detection elements. At least one spring having a flexibility larger than that of the substrate is arranged between the strain gauge and at least one of the pressure members, said substrate and said spring being in contact with one another so as to be jointly subjected to deformations. The spring may be a blade spring, a helical spring, or a cylindrical buffer spring. The excursions of the pressure members can be limited by means of stops. In the case of a blade spring the contact between the substrate and the spring can be controlled by giving the substrate a toothed shape or by providing it with contact elements.Type: GrantFiled: March 5, 1992Date of Patent: February 22, 1994Assignee: U.S. Philips CorporationInventors: Remy Polaert, Jean-Pierre Hazan, Francois Maniguet
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Patent number: 5283395Abstract: The weighing apparatus comprises a base (1) and a receiving platform (2) for the load to be weighed, parallel to said base, a test body (3) extending between the base (1) and the platform (2), the opposite ends (3a, 3b) of which are fixed rigidly to the base (1) and to the platform (2) respectively, one (3c) of the faces of the test body (3) comprising strain gauges associated with an electric circuit.The test body (3), molded in one single piece with the base (1) and the platform (2), is recessed.Used in particular for making bathroom scales.Type: GrantFiled: June 19, 1992Date of Patent: February 1, 1994Assignee: SEB S.A.Inventor: Bernard Pitaud
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Patent number: 5280141Abstract: A pressure compensating device includes a hermetically encapsulated weighing cell for neutralizing an excess pressure or a negative pressure within the encapsulation relative to a surrounding space. A pressure compensating diaphragm is connected to a protective housing in an essentially sealing manner, but without significant resistance and non-deformable relative to an initial tension. The pressure compensating diaphragm is of an extremely flexible material and the surface area thereof is large relative to the dimensions of the encapsulation. The pressure-compensating device preferably is a structural group mounted on the protective housing in which at least one pressure-compensating diaphragm is arranged so as to be protected against mechanical or chemical damage.Type: GrantFiled: June 1, 1992Date of Patent: January 18, 1994Assignee: Mettler-Toledo AGInventors: Christiaan Neeleman, Jean-Christope Emery
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Patent number: 5264666Abstract: A cargo hook having fore and aft trunnions mounted in fore and aft bearings supported on frame members of a helicopter or the like, is provided with strain gauges secured in a bore in the aft trunnion for measuring shear strain on the trunnion by a load supported by the cargo hook. Additional strain gauges are secured in the aft trunnion bore for measuring axial and Poisson forces on the trunnion as the axis through the fore and aft trunnions varies from horizontal. The strain gauges are included in an electric circuit of a Wheatstone bridge and an indicator which converts the electric signals from the strain gauges to a readout of units of load weight. The strain gauges which measure axial and Poisson forces are connected in the electric circuit to compensate for the deviation from horizontal of the axis through the fore and aft trunnions, to provide an accurate readout of load weight applied to the cargo hook.Type: GrantFiled: November 12, 1992Date of Patent: November 23, 1993Assignee: Measurement Systems InternationalInventors: David C. English, David H. Fish, Ronald A. Wenzel
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Patent number: 5250762Abstract: For measuring tensile force in a continuous strip or web, load cells are arranged between a bearing housing for a deflector roll, over which the web runs, and a fixed base. A load cell comprises a load cell housing and consists of two yokes (1, 2) facing the bearing housing and the base, respectively, and a force transducer which together with membranes (3 . . . 6) are arranged between the yokes to connect these together. At the end plates of the yokes, screw holes (8 . . . 15) are provided to attach the yokes to the bearing housing and the base, respectively. At each screw hole there is provided a gap (16) so that, around each screw hole, a tubular body is formed and that the plane outwardly-facing surfaces (17) of the bodies are plane-parallel and extend outside the otherwise plane outwardly-facing surfaces of the yokes.Type: GrantFiled: January 7, 1992Date of Patent: October 5, 1993Inventors: Par Gustafsson, Ake Persson
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Patent number: 5243146Abstract: A load weighing apparatus for weighing a weight of a load on a vehicle comprises an intervening element provided between a body frame and a suspension for transmitting the weight of the load to the suspension from the body frame. The intervening element is formed of a magnetic material and has a plurality of bore sections. An excitation winding is wound about the intervening element through ones of the bore sections, while a measurement winding is wound about the intervening element through the remaining bore sections. An electric power source for applying voltage is connected to the excitation winding. A measuring unit for measuring voltage across the measurement winding is connected thereto.Type: GrantFiled: January 28, 1992Date of Patent: September 7, 1993Assignee: Yazaki CorporationInventor: Katsuo Nishitani
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Patent number: 5239137Abstract: For the calibration of an electronic measurement system with sensors which are arranged in pairs on structural parts of an airplane undercarriage which are loaded transverse to the lengthwise direction and which give off measurement signals which correspond to the vertical displacement between two sensor attachment points which are staggered from each other in the lengthwise direction of the structural parts, the pair of sensors which form a measurement point in each case being arranged approximately in the horizontal central plane of the structural part at positions opposite each other on the outside, a method is proposed in which a separate scaling factor is determined for each sensor of the pair of sensors. For this purpose, the measurement signals and weights are preferably determined for at least two conditions of loading of the airplane which are as far apart as possible and, furthermore, in connection with at least two different torsional conditions of the loaded structural part.Type: GrantFiled: March 19, 1992Date of Patent: August 24, 1993Assignee: VDO Adolf Schindling AGInventor: Hans N. Patzig
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Patent number: 5232064Abstract: A portable weighing scale assembly which is comprised of a base structure including a double ended shear beam load cell structure. The shear beam load cell structure has top and bottom brace members and a spacer plate located at its center position and to which the load platform is mounted. The ends of the load cell structure are mounted to a support saddle and strap which are fixed to opposing base members of the base structure.Type: GrantFiled: November 27, 1991Date of Patent: August 3, 1993Assignee: Intercomp CompanyInventors: William P. Kroll, Robert E. K. Kroll, Kai K. K. Kroll
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Patent number: 5230252Abstract: A load cell incorporates two identical sensing beams equipped with resistance-type strain gauges. The beam geometry is such that a large constant shear strain is developed at the strain gauge locations. Two different strain gauge arrangements are used to provide linear response to axially applied forces while rendering the transducer insensitive to extraneous forces and couples. The geometry allows a fully redundant set of gauges to be placed on the beams for high reliability applications. Bridge balance and temperature compensation are accomplished by optimizing the direct deposited thin film gauge material which are then laser trimmed.Type: GrantFiled: September 30, 1991Date of Patent: July 27, 1993Assignee: Eastman Kodak CompanyInventors: Michael J. O'Brien, William B. Smith
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Patent number: 5228527Abstract: A double ended shear beam load cell assembly providing a structural weight bearing component for a portable, low profile weighing scale. The load cell has an elongated rectilinear beam structure with a pair of aligned and laterally opposing apertures which define internal, spacially parallel end walls adjacent the ends of the beam. Strain gauges are mounted in a predetermined orientation on the aperture end walls of the beam. Top and bottom brace plate members and a spacer plate are mounted to the central portion of the beam. The load cell beam ends are further provided with structure for mounting in a weighing scale base.Type: GrantFiled: November 27, 1991Date of Patent: July 20, 1993Assignee: Intercomp CompanyInventors: William P. Kroll, Robert E. K. Kroll, Kai K. K. Kroll
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Patent number: 5222398Abstract: A load cell having a loading flexure defining mounting slots for receiving the ends of a strain sensing beam. The strain sensing beam is an I-shaped member having a tapered width along its length and bearing pairs of strain gauges on the top and bottom sides. The strain sensing beam is mounted in the slots of the loading flexure with an amalgam. The thermal coefficients of expansion of the strain sensing beam, the strain gauges, and the amalgam are all matched to within a factor of 2 to provide an inherently thermally compensated load cell that is easily manufactured and free from hysteresis.Type: GrantFiled: November 1, 1990Date of Patent: June 29, 1993Assignee: Eastman Kodak CompanyInventor: Michael J. O'Brien
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Patent number: 5220971Abstract: A shear beam, single-point load cell is provided. The load cell includes a shear beam with a pair of shear strain gauge sensors mounted on opposing sides thereof for measuring strain within a small portion of the shear beam. The strain gauges are isolated within sealed pockets from moisture or harsh chemicals. The use of a shear beam, rather than a bending cantilevered beam of conventional load cells, allows the load cell to be sturdier and more robust than conventional load cells, to thereby measure and detect greater amounts of load. The provision of the strain gauges positioned for measuring strain within a small portion of the shear beam allows the load cell to accurately and precisely measure loads regardless of the mounting position of the load on the load cell. Further, the provision of closely adjacent strain gauges renders the load cells relatively immune to thermal gradients inherent in conventional load cells having widely separated strain gauges.Type: GrantFiled: September 24, 1991Date of Patent: June 22, 1993Assignee: SensortronicsInventor: Emory W. Farr
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Patent number: 5219031Abstract: A dynamic weighing apparatus for determining the mass of a group of particles or single particle while in motion is disclosed. The apparatus comprises a guide for guiding the material to be weighed along a predetermined path and having an entry end and an exit end. A transducer is operatively associated with the exit end of the guide and includes a mechanical column connected between a load cell and the exit end of the guide means. The load cell produces an electrical output signal proportional to the mass of particles on the guide.Type: GrantFiled: February 28, 1991Date of Patent: June 15, 1993Inventor: Robert O. Brandt, Jr.
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Patent number: 5199519Abstract: A strain gauge element in which the compression forces applied by at least one of the pressure members are transmitted to a first surface of the strain gauge by a cross formed by two cylindrical rods, the contact between the strain gauge (or the said pressure member) and the cross being exerted on a generating line of one of the rods (or the other rod) of the cross, permitting the said pressure member to carry out a tilting movement about the said rod (or the other rod).The reactionary compression forces applied to a second surface of the strain gauge are applied either by at least one cross or by rods.Type: GrantFiled: November 5, 1991Date of Patent: April 6, 1993Assignee: U.S. Philips Corp.Inventors: Remy H. F. Polaert, Jean-Pierre Hazan
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Patent number: 5199518Abstract: A load cell includes a deformable member having a chamber therein extending parallel to the direction of force. A plate on the deformable member extends transversely to the direction of force and to the axis of the chamber. The plate is welded to the deformable member such that it covers the chamber. The plate and welding carry the structural loads of the deformable member. Strain gauges are positioned on the interior sides of the chamber.Type: GrantFiled: February 19, 1992Date of Patent: April 6, 1993Inventor: Sheldon Woodle
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Patent number: 5190117Abstract: A load cell supporting member includes a central portion formed to receive a load cell and to protect a load cell from overloading. A plurality of arms extends radially from the central portion. The supporting member is a single, integral piece of said material.A weighing scale includes a first supporting member, a load cell supported by the first supporting member. The scale also includes a second supporting member, that is identical to the first and supported by the load cell and is identical to the first supporting member. The second supporting member supports a scale platform.Another weighing scale includes three identical supporting members and the load cells. A first supporting member supports a first load cell. The first load cell supports a second supporting member, which supports a second load cell. The second load cell supports a third supporting member. The third supporting member supports a scale platform.Type: GrantFiled: August 15, 1991Date of Patent: March 2, 1993Assignee: Pitney Bowes Inc.Inventors: Gerald C. Freeman, Norman Lilly
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Patent number: 5190116Abstract: A transducer which includes a central portion (12) having two longitudinally extending parallel rigid beam members (14,16) and two transverse parallel flexure members (30,32) which extend between the two rigid beam members (14,16) at right angles thereto. The rigid beam members (14,16) include end element portions (18,20). Flexure joints (58,60) and mounting portions (62,64) are located longitudinally outboard of the flexure joints (58,60). The flexure members (30,32) each include two cutout portions (34,36,40,42) defining flexure points. Strain gauges (46,48,50,52) are placed in the vicinity of the cutout portions (34,36,40,42) and are electrically connected into a bridge to produce an electrical signal output indicative of the load on the vehicle. The transducer is mounted by means of a mounting element (79) which includes two opposing mounting pad portions (82,84) and an intermedicate center portion (86).Type: GrantFiled: October 18, 1991Date of Patent: March 2, 1993Assignee: Stress-Tek, Inc.Inventor: Keith W. Reichow
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Patent number: 5183125Abstract: A load-sensing element for a balance comprises a beam which receives the load at one end, with a horizontal recess. The bending points of two guide rods formed by sections of substantially reduced material cross-section on the upper and lower faces of said recess provide a parallel guide. The measurement signal is derived by means of two wire strain gauges at the bending points on the upper face. The lower guide rod has a shoulder between the bending points at which the external cross-section of the beam widens. As a result, the centrelines of the material cross-section of the bending points formed by this guide rod are mutually offset by a certain distance. In an alternative to the formation of the shoulder, wire strain gauges are provided at the bending points on the upper surface of the upper beam and on the lower surface of the lower beam.Type: GrantFiled: July 11, 1990Date of Patent: February 2, 1993Assignee: Soehnle-Waagen GmbH & Co.Inventor: Michael Schurr
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Patent number: 5183126Abstract: The weighing device has a bending beam (20,31,41) from which bending moment transmission means (35,36,42,43) extend laterally. Relatively rigid members (24,27,30,32) are coupled to the bending moment transmission means (35,36,42,43) by force transmission elements (13,37,38). Loads applied to the rigid members (24,27,30,32) are measured by a strain gauge (33) mounted on the bending beam (20,31,41). Each force transmission element (13,37,38) comprises a rectangular prismatic body of elastomeric material, such as natural rubber, which may have concave sides (15) to reduce shear forces in the body. Fixing studs (17) may be attached to plates (16) bonded to the upper and lower surfaces of the body. The material of the body is chosen to exhibit creep, hystersis and linearity characteristics approximating those of an ideal spring.Type: GrantFiled: September 19, 1991Date of Patent: February 2, 1993Inventor: Arthur Kellenbach
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Patent number: 5154247Abstract: Disclosed herein is a load cell provided with a high-precision load-sensing member of ceramic on which are formed patterns of thin-film resistance for strain gages which are not subject to breakage and variation of resistance. The load cell comprises a bending beam of ceramic material and strain gages of thin-film resistance formed thereon, with the bending beam having a surface coated with amorphous glass on which are formed said strain gages of thin-film resistance. The strain gages are formed from an alloy composed of iron and one or more selected from chromium, cobalt, tungsten, molybdenum, niobium, and tantalum, and a small amount of impurities.Type: GrantFiled: October 30, 1990Date of Patent: October 13, 1992Assignee: Teraoka Seiko Co., LimitedInventors: Yoshinobu Nishimura, Hiroshi Tanaka, Naoji Nakamura
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Patent number: 5135062Abstract: A strain gage transducer system, such as a load cell based weighing system, is protected against moisture related errors by an electrically conducting guard circuit for terminals and other parts subject to wet or humid conditions. The guard circuit is connected to an electrical potential close to a potential of signal terminals in a strain gage bridge, for instance to a center tap in a power supply for the strain gage bridge.Type: GrantFiled: March 15, 1991Date of Patent: August 4, 1992Assignee: Flintab ABInventors: Harry E. Lockery, Rolf P. Haggstrom
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Patent number: RE35301Abstract: A load cell for on-board weighing applications, including an elongated sheer force measuring beam (24) which includes mounting means (52,54,56) for securing the opposing longitudinal ends of the beam (24) to the frame (58) of the vehicle. The load is applied against the upper surface (32) of the beam (24) through a platform (20) or the like. The shear strains caused by the load are concentrated in an area near each end of the beam (24). The strain measuring means (30) are located in holes in the sides of the beam in the shear force areas and measure the shear strains on the beam, which in turn are representative of the weight of the load.Type: GrantFiled: July 5, 1994Date of Patent: July 23, 1996Assignee: Stress-Tek, Inc.Inventor: Keith Reichow