Abstract: A levered scale for weighing human beings is disclosed in which weight measurement is produced by direct tensile loading of at least one stress-dependent transducer that is bonded to the central member of an improved tension link plate which is pivotally supported at one end by a U-shaped bracket and pivotally coupled at the opposite end to lever arms. The thin tension link plate, which is made of elastically deformable sheet metal, is received between the sides of the U-shaped bracket. The tension link plate is connected directly to the U-shaped bracket by a first cross pin and to the lever arms by a second cross pin. The resultant force produced by the weight of the load applied to the scale produces vertically downward movement of the lever arms thereby providing tensile loading of the tension link plate and the stress-dependent transducers bonded or deposited thereto.

Abstract: A large-load gauging device comprising a load converter having strain gauges attached thereto at suitable locations on the inner and outer peripheries thereof, a load concentrating ring mounted on the load converter, a load dispersing plate mounted on the ring, and a load concentrating seat mounted on the dispersing plate.With its setup as such, the gauging device provides an advantage of reduced height and weight as well as reduced cost and is able to perform accurate measurement of large loads.

Abstract: A weight detection circuit for a load cell scale which connects an operational amplifier directly to an-output of a bridge circuit of a load cell so as to simplify a conventional differential amplifier, thereby enabling simplification of the overall weight detection circuit to result in a reduction in manufacturing cost. Furthermore, a bias resistance is connected directly to the bridge circuit for the load cell thereby also to simplify the bias circuit to lead to a further reduction in manufacturing cost.

Abstract: An electronic scale in particular intended to be used as a platform scale. The scale comprises a sensor device having six supporting points which in a plan view form the corners of two triangles. The supporting points situated at the corners of one of the triangles are connected to a base whereas the scale pan is supported at the supporting points at the corners of the second triangle. The sensor device comprises a body which is so connected to the different supporting points that it is subject to a bending moment when the scale pan is loaded. The sensor device is also provided with electrical means for indicating the bending moment.

Abstract: In a liquid quantity detecting apparatus, a torsion bar is mounted on a stationary structure to support a container thereon in such a manner that the torsion bar is twisted at a torsional angle in dependence upon the weight of liquid stored within the container. An electric detector is provided to electrically detect the torsional angle of the torsion bar so as to generate an output signal indicative of the quantity of the stored liquid based on the detected torsional angle.

Abstract: A shear beam load cell comprising a cantilevered beam member having a free end weigh section for receiving a load force to be measured, a mounting section for securing the beam member, and recesses formed in opposing sides of the cantilevered beam free end weigh section for defining an unsymmetrical I-shaped cross-section. The recesses have dimensions such that one of the recesses has its bottom wall surface insensitive to torsion. In one embodiment, the recess with the bottom surface insensitive to torsion has a depth longer than the other recess. In another embodiment, the recess with the bottom surface insensitive to torsion has a height shorter than the other recess. A strain gage sensing device is positioned in that one recess on that bottom wall surface insensitive to torsion for measuring the shear strain corresponding to the load force applied to the free end weigh section of the beam member.

Abstract: An apparatus for separating and collecting plasma from whole blood includes a volume monitoring system which provides a continuous display of the volume of plasma collected. A transducer circuit within the system develops an electrical signal frequency-dependent on the weight of the collected plasma. The frequency of this signal over a present measurement interval is periodically compared with the frequency of the signal over a preceding measurement interval to develop a difference signal. If the difference is determined to be positive and less than a predetermined maximum collection rate so as to constitute a valid collection increment, the difference is cumulatively added to previous collection increments in a cumulative display counter to provide a collected volume display, and the frequency of the present measurement interval is taken as a frequency of the preceding measurement interval for the next comparison.

Abstract: A platform type weighing scale having four platform suspensions mounting a scale platform on a base, a bendable load sensing beam supported by a pair of spaced beam suspensions on the base, first and second transfer means respectively interconnecting first and second pairs of said platform suspensions to each other and to sensing beam at first and second points spaced along the beam to preselected distance from the first and second beam suspensions respectively to apply first and second forces to the sensing beam in a direction transverse thereto that are respectively correlative with the sum of the loads applied to the first and second pairs of platform suspensions, and electrical transducer means for sensing the sum of the moments produced in the sensing beam by the first and second forces.

Abstract: A load cell having a parallelogram configuration formed by a pair of spaced-apart, generally parallel force-receiving members interconnected by a cantilever beam and a parallel spacer beam. The cantilever beam projects perpendicularly from one of the force-receiving members, and its end is secured to the other beam by a flexure hinge. The ends of the spacer beam are secured to the force-receiving members by respective flexure hinges. In order to maintain the parallelogram configuration of the load cell, the length of the spacer beam is equal to the length of the cantilever beam from the beam's virtual pivot point to its end. Rotational moments imparted to the force-receiving members apply forces to the beams along their longitudinal axes without deflecting the cantilever beam, thus making the load cell insensitive to such moments. A reduced thickness portion instrumented with semiconductor strain gauges is formed in the cantilever beam near its point of attachment with the force-receiving member.

Abstract: This invention relates to new and improved single beam load cells which are compensated for both longitudinal and lateral displacement of the load; to new and improved scale arrangements incorporating such load cells; and to methods of compensating such single beam load cells. In one embodiment of the invention strain gages are attached to only one side of the beam and the beam is honed or filed to compensate for both longitudinal and lateral displacement of the load. In another embodiment of the invention strain gages are placed on both sides of the single beam and the strain gages are placed on the beam at a slight angle from the longitudinal axis of the beam. In this embodiment the beam may be honed to compensate for both lateral and longitudinal displacement of the load.

Abstract: The base of a weigh scale includes openings in the bottom thereof at each corner. The base is raised above a supporting surface by way of rigid foot members aligned with the openings in the corners of the base. Load cells in the form of deflection beams each having one of their ends fixed to the base while their other end contacts upper surfaces of their respective foot members. Damage to the load cells by side shock loads is eliminated by way of resilient coupling members connected between the foot members and the base.

Abstract: A force sensing apparatus comprising a parallelepipedic block (1) having an application area (2) and a reception area (8) for the force to be measured thereby, upper transverse openings (10,11) connected by a slot (14) and lower transverse openings (12,13) connected by a slot (15). The transverse openings (10,11,12,13) determine zones of lesser strength (20,21) and vertical slots (25,26) determine a zone of lesser strength (35) therebetween, the minimum thickness of which is located on the axis X--X of the zones of lesser strength (20,21) determined by the openings (10,11,12,13).

Abstract: The transducing apparatus for a dynamometer includes a band shaped measuring element which is subjected to a load-dependent tensile force. The measuring element is made of an amorphous metal. It is band-shaped and may have one or two necked-down portions whose resistance varies as a function of applied force. Such measuring element has particularly desirable mechanical characteristics such as high limits of permissible applied force, resistance to creep, low hysteresis, and stability with respect to temperature variations.

Abstract: A weighing apparatus of the type which weighs articles through use of a load cell having strain gauges attached thereto, the apparatus including a sealed vessel filled with a liquid of a specific gravity greater than unity for housing the load cell which is immersed in the liquid, a diaphragm provided on the sealed vessel so as to close an opening formed in a portion of the vessel, a supporting member for supporting a container carrying the articles to be weighed, and a connecting member for mechanically connecting the supporting member with a load-receiving portion of the load cell through the intermediary of the diaphragm.

Abstract: In a strain gage weighing scale with a load platform, a plurality of foot structures support the platform. The invention is an improvement in each foot structure of a sandwich with a bottom support plate, a pair of spaced first cylindrical roller fulcrums on the plate, a floating beam plate on the first fulcrums and spaced above and coextensive with the bottom plate. A pair of differently spaced and equally offset second cylindrical roller fulcrums on the beam plate support the platform. Suitable strain gages are secured to the beam any place between the closer pair of fulcrums. The entire sandwich is held together by a deformable plastic housing that secures the plates and fulcrums together and is barb-connected to the platform. The strain gages are connected to conventional converting structure measuring the change in resistance under load and calibrated to read weight. The deformable plastic housing holding the sandwich is an integral molding with structural details reducing friction between the parts.

Abstract: A platform scale with a low overall height primarily for use as a bathroom scale. A platform receives the load to be weighed and transfers a force to a lever arrangement that converts strains due to load into an electrical signal which is then converted to a weight indication.

Abstract: A load cell of integral unitary construction wherein strain gages are mounted on the peripheral surface of a solid disc-shaped measuring body and are responsive to shear strain induced in the solid measuring body by an applied load. The load receiving and load cell supporting ends are incorporated into the integral unitary structure.

Abstract: The weight of items carried by a fork lift truck may be measured by this fork lift scale. This fork lift scale consists of horizontally disposed load sensors connecting a crossbar frame to the crossbars of the fork lift truck. Forks are supported by the crossbar frame. Strain gages are mounted on the load sensors to sense the weight of items carried on the forks. The strain gages are mounted to sense vertical shear or bending in the load sensors. The strain gages are positioned on the load sensors and are electrically interconnected so that types of loading, other than vertical loading due to the weight of items placed on the forks, are rejected and not measured by this fork lift scale.

Abstract: A constant strain load cell for measuring forces applied to the cell which includes a parallelogram shaped body having fixed and movable end constraints interconnected by upper and lower flexures with flexing areas at the opposite ends of the flexures functioning as sensing beams and on which strain gages are mounted. The flexing areas are formed so that bending stresses caused by applied loads are maintained constant over the flexing areas or regions. The load cell can be easily machined or extruded and the capacity can easily be varied dependent only on the overall size.

Abstract: A weigh section of a railway track consists of two unsupported spans of conventional rail, produced by removing two adjacent supporting ties for example. The span of the unsupported rails is approximately 64 inches, less than the minimum distance between adjacent axles of a railcar. Four strain gauges are mounted on the under surface of the unsupported rail span of each rail, the four gauges consisting of two pairs of outboard and inboard gauges located in respective halves of the unsupported span. The outputs of the four strain gauges for an unsupported span are summed by adding the outputs of the inboard gauges and subtracting the outputs of the outboard gauges. This sum produces a constant value representative of the load supported on the rail as the axle load moves between the two inboard gauges. A limit switch tripped by a wheel of each axle activates a computer.

Abstract: A sheave basket weighing system is disclosed for use in a material handling apparatus. The weighing system comprises a sheave basket with three bending beam load cells fixed on the sheave basket to provide a three-point support system. One of the load cells is preferably positioned intermediate to the other two load cells. A ladle hanger assembly is supported on top of the load cells. The weighing system provides a stable three-point support which can withstand side loading without the necessity of movable load cells and without the use of check rods, which could result in weighing inaccuracies.

Abstract: A plurality of load bar assemblies (14) are connected between a supported structure (10) and a supporting structure (12) for determining an amount of load in the supported structure. Each load bar assembly includes a load bar (20) having a middle portion (22) connected with the supported structure and end portions (24, 26) connected by load bar mounting assemblies (34) with the supported structure. Each load bar mounting assembly includes a fulcrum member (50) which supports the load bar end portion on a fulcrumming surface (54). An elongated connecting structure (60) having an enlarged upper portion (64) extends through a load bar end portion aperture (32) and a fulcrum member aperture (56) and is connected with the supporting structure. An annular washer (72) and a tubular sleeve (74) of resilient material are disposed between the elongated connecting structure and the load bar end portion to allow limited movement therebetween.

Abstract: In a platform scale in which the strain gage transducer beams are preferably formed as an integral part of a platform it is important that any distortions such as horizontal or angular force components that could falsify the reading of the weight, are prevented from affecting the transducers. For this purpose, the vertical load or weight representing force components are transmitted to each strain gage transducer beam through at least two cooperating curved, preferably spherical, surfaces. One curved surface has a larger curvature than the other so that a sufficient motion in any horizontal direction is permitted. The horizontal yielding prevents the transmission of a horizontal or angular force component to the sensing strain gages of the respective transducer beam but does not adversely affect the vertical force transmission to the transducer beams.

Abstract: A member of composite material incorporates at least one strain responsive member within a part at which a strain is induced by a load in use. A signal which is a function of a strain detetected by the strain responsive member is communicated to an indicator or monitoring device which registers the applied load causing the strain.In one embodiment a leaf spring for a vehicle comprises upper and lower elements of one or more superimposed strips of pre-impregnated longitudinally extending carbon fibres and an inner element of one or more strips of pre-impregnated glass fibres. During laying up of the strips two strain gauges (13, 14), which may be on or integral with a carrier strip, and their leads (13a, 13b, 14a, 14b) are introduced into the active length of the spring which experiences a bending moment on the application of a load. The gauges are positioned at a pre-determined distance apart which is maintained when the member is cured, as by hot press moulding.

Abstract: A platform scale has at least three transducers carrying the platform. The transducers are mounted upon a base and are tangentially oriented with respect to a centerpoint. Thus, deformation of the transducers upon application of a force is translated into rotary movement of the platform, and stresses which cause inaccuracies are reduced or eliminated.

Abstract: Laundry treatment machine including a housing, a carrier disposed in the housing, a laundry drum rotatably supported by the carrier, the carrier having parts thereof being exposed to loads affected by the weight of the drum, electro-mechanical transducers being disposed on the parts of the carrier and producing output signals representing a measure of the weight and the weight change of the drum, and a signal processing device receiving the output signals.

Abstract: A weighing device for fluent materials, for example grain, enables a flow of the material to be weighed.The device includes a sensor member with an inclined surface over which the flow passes. The member is supported in cantilever and the force on the member due to the flow of material is sensed by sensing means.The sensing means senses the bending forces, or other physical characteristic of the member at two positions along the member and the resulting signals are compared to give an output signal corresponding to the weight of material passing over the member.The sensing means may be strain gauges arranged in a Wheatstone bridge circuit the output from which is passed to integrating means.

Abstract: Device for determining the quantity of the contents of a tank (1) mounted in a frame (3,4) which rests on a base with four points of support disposed in the corner points of a rectangle, two adjacent points of support being constituted by force measuring elements (6) each consisting of a generally block-shaped body (7) of metal, in which an opening (8) is cut out such that at the lower and upper sides of the body two relatively thin elongated and substantially horizontally extending portions (9,10) are formed which are connected to each other at both ends by thicker material portions disposed at the vertical sides of the body, whereas at the lower side of the body a foot (11) is formed which protrudes from one vertical side towards the vertical axis of the body, and with which the body rests on the base, and the supporting frame (3,4) of the tank is affixed on the upper side of the body near its other vertical side, and two strain gauges (T1,T2) aligned in spaced apart relation with each other in the directio

Abstract: An electronic balance includes a pan, a first means for measuring a load normally applied to the pan, a second means for detecting a possible deviation of the load acting point from the required point on the pan, a third means for correcting an error in the measured value due to the deviation, and a fourth means for outputting the corrected value.

Abstract: A low profile scale utilizes four strain gage-based sensing beams which are isolated from mechanically or thermally-induced distortions on the weighing platform by means of interposed elastic elements. The platform is capable of moving upwardly relative to the sensing elements without transmitting any load thereto. The platform cooperates with a floating lower enclosure system to essentially seal the mechanism so that it is splash proof and washable as required for use in the food industry. Adjustable overload stops channel excess forces around the sensing beams to protect them from damage.

Abstract: A single unit made of a light metal or alloy preferably in a diecast process is shaped to constitute the frame, the levers, and hinged bearings of a platform scale. Even the measuring element can be integrated into this one-piece unit. The resultant scale has a very low profile and is particularly suitable for mass manufacture for applications not requiring excessive resolution as, for example, post office scales or scales for home use.

Abstract: A force measuring device comprising a load receiving platform supported by a multiple bending parallelogram beam type load cell is provided with a plurality of electrical strain gages. Strain gage elements mounted on one of the beams are displaced toward one side of the beam and strain gage elements mounted on the other beam are displaced toward the other side of the other beam. An appropriate resistor network is connected to at least one strain gage on one or both of the beams to correct for either longitudinal or transverse displacement of the load on the platform. To correct for both transverse and longitudinal displacement of the load a resistor network is connected to each of three of the strain gages. Suitable procedures for determining the values of the resistor networks in combination with the above structure are included.

Abstract: An electronic scale is provided with two or more load cells in which the first load cell covers a low load range, and each successive cell covers a greater load range than the preceding cell. The cells are connected mechanically in tandem such that a load on the scales is applied to each cell simultaneously. Electrical signals from each load cell when performing a weighing operation are processed by a microcomputer to digitize the signals and to select the signal coming from the first load cell in the tandem connection which is not overloaded. The microprocessor scales the measurement signal and displays the weight on an alphanumeric readout. Memory circuits are included for storing tare weights and for storing unit weights during counting operations. When a number of units in a group is to be counted, the microprocessor divides a measured weight by the unit weight and outputs the count to the alphanumeric readout display.

Abstract: A load cell is disclosed, which is especially applicable for use with electronic counting and/or weighing scales and the like. The load cell comprises a parallelogram-type flexure frame, and is characterized by four strain gauges, which are located at the upper and lower surfaces of two vertically overlying corner flexure regions of the parallelogram. This arrangement--because of symmetry considerations--is uniquely free of second-order errors generated by offset loading on the weight-receiving platform via which the generally vertically-directed forces to be measured by the cell are applied. At the same time, the arrangement provides two corners completely free of strain gauges, providing sites which can be trimmed by filing or so forth to compensate for small symmetry errors present in the load cell as originally fabricated and assembled.

Abstract: The device includes: a set of four strain-gauges mounted on a cantilevered beam, which gauges are electrically connected among themselves in the form of a bridge (9), in a manner such that said bridge produces an output voltage (.DELTA.V) which is a function of the magnitude of the force applied to the beam, when the bridge (9) is supplied with current; a source of voltage (10), designed to supply the bridge (9); an analog-to-digital converter (16), connected to the output of the amplifier (14), with which there is associated a microprocessor (24); and a display unit (13), connected to an output of the microprocessor (24), which is designed to allow the display of a signal that is representative of the magnitude of the force applied to the beam.

Abstract: A digital scale and circuitry therefor, includes a power supply electrically connected to a control logic circuitry and a bridge supply circuitry. The bridge supply circuitry is electrically attached to a strain gage bridge which is electrically connected to an amplifier circuitry. The amplifier circuitry electronically engages an AD converter which electrically connects to a logic circuit and the control logic circuitry. The logic circuit and the control logic circuitry are electrically interconnected and each electrically attach to a display driver circuitry for displaying digits on a digital screen.

Abstract: A medical patient weighing scale is disclosed which comprises an elongated, flat, rigid pan, a plurality of thin, electronic bending beam load cells mounted in the pan, and a rigid, elongated, flat cover freely supported on the load cells. The cover is of sufficient size to support a patient in a supine position. The weighing scale is extremely thin, and may be conveniently mounted or stored when not in use. Accurate weight measurements are provided almost instantaneously on a digital display on the cover.

Abstract: A track scale weighs a load on a track. The scale comprises a live rail for supporting the load to be weighed. A pair of load cells spaced longitudinally of the live rail support the live rail. The load cells have sensing means for sensing shear stresses and providing a signal indicative of the load supported by said load cells. Each of the load cells have a projecting portion extending transverse to the live rail and supporting the live rail. A bearing is interposed between the projecting portion of each load cell and said live rail. The bearing is constructed to allow for movement of the live rail relative to the load cells.

Abstract: A weigh scale includes a flexure beam disposed between a platform and the base. Load transmitting devices operate to deflect the beam as a function of the load placed on the platform. Overload protection is provided for the beam to restrict the amount of beam deflection to maintain it within its elastic limits to thereby prevent yielding of the beam.

Abstract: A weigh scale includes a flexure beam disposed between a platform and the base. Load transmitting devices operate to deflect the beam as a function of the load placed on the platform. Overload protection is provided for the beam to restrict the amount of beam deflection to maintain it within its elastic limits to thereby prevent yielding of the beam.

Abstract: A cart for weighing small animals with the cart having a torsional undercarriage mechanism that directs the weight of an animal in a weighing pen through a single tension support member wherein the elastic deformation of the single tension support member is measured with an electrical resistance strain gauge mounted on the tension support member and a conventional digital strain gauge read-out device.

Abstract: A mechanical force to electrical signal transducer includes a flexible metal body operable as a beam in which a bending strain is to be measured as a measure of a mechanical force. At least a part of one surface of the metal body includes an electrical insulating material with a resistance element formed from a layer of a thick film resistor ink of the type used for thick film integrated circuits fused upon the electrical insulating material. A plurality of such transducers may be combined in a weighing scale, with the individual transducers electrically interconnected to provide for electrical summing of the transducer signals to provide a total weight measurement.

Abstract: A bathroom scale which uses an electronic circuit for providing a digital output voltage in response to the placing of a weight thereon, the electronic circuit having operational amplifier circuits which use both a positive power supply and a negative power supply, the latter assuring that the op-amps always return to a stabilized ground reference point to assure repeatability of weight measurement. The unit includes means for permitting the digital output voltage to reach a steady state value during a selected time period after a weight is placed on the scale and for preventing such steady state value from changing after such selected time period. The gain of the op-amp circuitry is adjustable to permit scale calibration to be performed.

Abstract: A device at an electromechanic platform scale with an inherent stable platform (1-3), the supporting points of the platform against the foundation provided with load measuring means in the form of substantially horizontal beams with load sensing cells (4), each of which transduces part of the load of the platform to an electric signal.It is characteristic of the device that one end of each beam is connected to the platform (1-3) so that the connection (7,8,9) is rigid in vertical direction and elastically resilient in horizontal directions, at least in the direction perpendicularly to the longitudinal axis of the beam, and that the other end of the beam is connected to the foundation (19) of the platform so that the connection (10) is elastically resilient in both vertical and horizontal directions as well as to moments about axes in corresponding planes.

Abstract: The equipment according to the invention is suitable for the measurement of very small weight forces by conversion of the forces to be measured to 5-100-fold value. The equipment has two units, each containing at least three measuring arms, where the connection points of the measuring arms are attached to an extension bar, and the free ends of the measuring arms are connected to a single rigid element in such a way, that the connection points of the measuring arms are outside the planes fixed by the ends attached to the rigid element. The measuring arms and extension bar in the equipment are formed as pull rods. The measuring arms are arranged symmetrically or asymmetrically, and their number is optional. Infinite number of measuring arms may be used, in which case they are formed as membranes in the practice. Force-meter sensors, suitably elongation measuring resistors are built into the measuring arms, thus the output signal gives directly the measured value.

Abstract: The present invention relates to a load receiver. This load receiver comprises a fixed upright integral with a frame, a loaded upright integral with a load-carrying plate and two arms hinged on the uprights to form therewith a deformable parallelogram, and two uprights and the two arms together forming an integral structure, provided with constrictions which define the hinges of the deformable parallelogram, and a load transducer provided to detect the deformation of the parallelogram under the effect of a load applied on the plate. The load receiver is of use notably for commercial balances.

Abstract: Mass and force meter with a body, a load support, a load cell, an intermediate body mounted between said body and said load support and supported by said body over a number of supporting points, said load support being supported by said intermediate body over the same number of loading points, whereby said supporting and loading points are mounted pairwise in the same horizontal plane, said intermediate body consisting of two rigid parts linked by two horizontal, flexible parts mounted one below the other, said supporting and loading points being anchored to said rigid parts, said loading points being shifted horizontally by the same amount and in the same direction from said supporting points, whereby at least one spring, the resilience of which is much greater than that of said flexible parts, has one of its ends fitted into one of said rigid parts, its other end being linked with said load cell which is linked to the other rigid part.

Abstract: A position locating system for calculating the coordinates of a localized force applied to a surface (101a) has force sensing devices (101, 501, or 501a) for supporting the surface (101a). The force sensing devices provide force proportional electrical signals to a processing system (512) for calculating the position of the localized force applied to the surface. In order to provide samples of the dynamic alternating current characteristics of the force proportional electrical signals to the processing system, the improvement comprises an alternating coupling circuit (508) associated with each force sensing device. The alternating current coupling circuit accentuates the common dynamic frequency characteristics of the variety of forces presented to the system. The sample collection circuit (511) of processing system (512) sequentially collects samples (401a) of the force proportional electric signal from each AC coupling circuit (508).

Abstract: A measuring plate with at least one strain gauge and upon which a wheel of a vehicle can rest to generate a signal which is used to indicate or register the wheel load or axle load of the road vehicle, is received in a frame and has edges which extend transversely of the direction of vehicle travel. According to the invention, these edges are bevelled or partly cut away so as to be overhung by complementarily shaped sides of the frame. These edges also are provided, along the bottom of the plate, with elastic bars or ribs which rest upon and support the center of the plate above a support plate or body disposed below the measuring plate. The plate can have these edges covered with an elastic material, especially a clear elastomer or the entire measuring plate can be sheathed in the elastomer.

Abstract: A load-cell balance in which strain gauges are mounted on a recess portion of the flexible arms of the balance. The circuitry for the strain gauges is mounted on a printed circuit board which is fixed to the stationary portion of the balance and extends along the length of the flexible beams. An electrically shielding cover may be provided for the load balance, as well as compensating resistances.