EP2409122A1 - Sealed sensor with strain gauges - Google Patents

Sealed sensor with strain gauges

Info

Publication number
EP2409122A1
EP2409122A1 EP09824254A EP09824254A EP2409122A1 EP 2409122 A1 EP2409122 A1 EP 2409122A1 EP 09824254 A EP09824254 A EP 09824254A EP 09824254 A EP09824254 A EP 09824254A EP 2409122 A1 EP2409122 A1 EP 2409122A1
Authority
EP
European Patent Office
Prior art keywords
test body
hinges
recess
measuring
hinge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09824254A
Other languages
German (de)
French (fr)
Inventor
Jean-Pierre Aumard
Vincent Bourdarel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
S C A I M E SA
Original Assignee
S C A I M E SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by S C A I M E SA filed Critical S C A I M E SA
Publication of EP2409122A1 publication Critical patent/EP2409122A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G3/00—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances
    • G01G3/12—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing
    • G01G3/14—Weighing apparatus characterised by the use of elastically-deformable members, e.g. spring balances wherein the weighing element is in the form of a solid body stressed by pressure or tension during weighing measuring variations of electrical resistance
    • G01G3/1402—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01G3/1412—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being parallelogram shaped
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01G—WEIGHING
    • G01G21/00—Details of weighing apparatus
    • G01G21/30—Means for preventing contamination by dust
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
    • G01L1/00—Measuring force or stress, in general
    • G01L1/20—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
    • G01L1/22—Measuring force or stress, in general by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress using resistance strain gauges
    • G01L1/2206—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports
    • G01L1/2243—Special supports with preselected places to mount the resistance strain gauges; Mounting of supports the supports being parallelogram-shaped

Definitions

  • the present invention relates to a measuring sensor of the type comprising a monolithic test body provided with strain gauges fixed on this test body in at least one of its zones of elastic deformation under the effect of an applied force. audit body.
  • test body is formed of a monolithic deformable bar which can have the form of a deformable parallelogram whose one end is fixed on a fixed frame and the other is arranged to receive a plate on which is placed the load to measure.
  • a monolithic deformable bar which can have the form of a deformable parallelogram whose one end is fixed on a fixed frame and the other is arranged to receive a plate on which is placed the load to measure.
  • sensors are described for example in US 4,150,729, US 4,546,838 or US 4,107,985.
  • the present invention aims at the realization of such a sensor that can be used in a hostile or corrosive environment, salt water, chlorine or acid, etc., which requires to protect the strain gauges to prevent their deterioration.
  • strain gauges are protected by a coating or film of a material resistant to corrosive agents.
  • experience shows that it is always this protection that degrades in the first place, requiring the replacement of the sensor although its mechanical part, the test body, is still intact.
  • the licensee has developed a leakproof sensor described in EP-1319931 in which the strain gauges and their associated electrical circuit are placed in a cavity of the test body whose edges to be closed by a welded plate are located in a zone of the test body not participating in the measurement, these edges being decoupled in particular from the measuring beam.
  • the test body comprises a main beam, connected to the measuring beam, distinct from the sides of the deformable parallelogram and through the central cavity of the test body whose machining remains complex and expensive.
  • the object of the present invention is the production of a strain-gage-proof sensor in which, on the one hand, the cavities receiving the strain gauges and their associated electrical circuit are arranged in such a way that their edges intended to be connected by welding to a metal cover are remote and mechanically decoupled from the deformation zones used for the measurement and, secondly, whose test body in the form of deformable parallelogram has a simple machining and in particular does not include a beam passing through the cavity central of this test body, so that we obtain a precise and cheaper sensor.
  • the purpose of the present invention is to provide a sensor comprising a monolithic proof body and encapsulated strain gauges, thus protected from the environment, which obviates the aforementioned drawbacks, that is to say which is resistant, the protection of gauges does not influence the measurement characteristics and is a lower cost of manufacture.
  • the present invention relates to a sealed measuring sensor comprising a monolithic proof body provided with strain gauges which is distinguished by the characteristics listed in the independent claim 1.
  • strain gauges which is distinguished by the characteristics listed in the independent claim 1.
  • Figure 1 is a perspective view of the sensor without its closure cap.
  • Figure 2 is a top plan view of the sensor shown in Figure 1.
  • Figure 3 is a bottom plan view of the sensor shown in Figure 1.
  • FIG. 4 is a side view of the sensor illustrated in FIG. 1.
  • FIG. 5 is a section along the line A-A of FIG. 4.
  • Figure 6 is an enlarged detail of Figure 5.
  • Figure 7 is a perspective view of the sensor shown in Figure 1, its closure cap being welded in place on the test body.
  • Figure 8 is a top view of a second embodiment of the sensor.
  • Figure 9 is a side view of the sensor shown in Figure 8.
  • Figure 10 is a bottom view of the sensor shown in Figure 8.
  • Figure 11 is a perspective representation of the sensor according to the second embodiment.
  • the subject of the present invention is a strain-gage-type weighing sensor of the single parallelogram type.
  • a deformable parallelogram proof body is used to accept the load eccentricities.
  • This sensor does not have, as is generally the case, a third complementary beam passing through the opening of the parallelogram, in order to simplify as much as possible the machining of the test body and thus reduce the cost price thereof.
  • This test body is formed of a parallelogram consisting of four hinges of which at least one but preferably two have a particular shape characterized by a narrow central portion connected on both sides by a very thin veil (0.1 to 0.4mm ) to the two outer parts sufficiently thick to support the welding of the metal closure sheet and thus form a sealed cavity accommodating the gauges and thus providing protection vis-à-vis the aggressive outdoor environment.
  • the narrow central parts (4 to 8mm) called hinges consist of a section of material between the flat part where the strain gauges are bonded and the concave face (radius of 6mm) so that the deformations are limited to these only thinned zones thus constituting a parallelogram having a fairly high stiffness.
  • connecting webs of the hinges to the outer parts are designed so as to present, thanks to their shape and their small thickness, the maximum possible flexibility in order to perfectly decouple the parallelogram of measurement of the external parts which ensure in association with the closing plate sealing the assembly.
  • the measuring sensor comprises a monolithic proof body 1 constituting a deformable parallelogram made of steel, stainless steel or alloy thereof, aluminum or other elastic material.
  • one end 1a is intended to be fixed on a frame while the other end 1b is equipped to receive a tray on which is placed a load to be weighed or applied a force to be measured.
  • This test body (see FIG. 4) is traversed transversely by a central recess 2 having the general shape of an H defining the four hinges a, b, c, d of the deformable parallelogram of which at least one (a) is a hinge measurement (see Figure 6).
  • Each end of the vertical branches of the H that forms the central recess 2 has a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1.
  • the two lower hinges c, d serving to deform the test body but not to the measurement are thin and can be further weakened by openings 3, 4 made in the lower wall of the test body 1. This is more particularly useful in the case of test bodies for low nominal loads.
  • the lower hinges c and d have a thickness of the order of 0.5mm to 1mm for example, depending on the nominal load of the sensor.
  • the upper hinges a, b are those parts of the proof body which not only will ensure the deformability of the test body but are used to measure the bending stresses that will be measured using strain gauges. These measurement hinges a, b, in some variants only one of these hinges is used for measurement, have a greater thickness, of the order of 1 mm to 2 mm for example, also depending on the nominal load of the sensor.
  • the figures given above are valid for sensors rated for a nominal load of 5 to 10 kilograms and as indicated above may vary depending on the rated load of the intended sensor. The higher the rated load, up to a few hundred kilograms, the heavier the hinges.
  • the upper face of the test body 1 comprises on the one hand a shallow recess 5 intended to receive strain gauges 6.7 fixed on the bottom of this recess 5 to the right of the measurement hinges a, b and, d on the other hand, a deeper housing 8 intended to house the electrical circuits 9 associated with the strain gauges 6, 7.
  • This recess 5 and this housing 8 have a flange 10 located in the same plane, parallel to the upper face of the test body 1. This flange 10 allows to position a closure plate or cover 11 covering and closing the recess 5 and the housing 8 which will be welded for example laser on said flange 10 to ensure perfect sealing of the recess 5 and the housing 8.
  • pairs of cavities 12 are machined on both sides of the test body delimiting a width of the hinges a, b used for the measurement, of the order of 4 to 8mm for test bodies of nominal capacity of 5 to 10 kilograms .
  • These pairs of lateral cavities also define the thickness of the webs 13 connecting the hinges a, b to the corresponding edges of the test body 1.
  • the material of the test body 1 which is used for the measurement of the stresses is limited to the measuring hinges a and b having a specific thickness and width.
  • the sails 13 of material connecting the hinge has, respectively b, to the upper lateral edges of the test body 1 are thin, of the order of 0.1mm to 0.4mm, and ensure a total decoupling between the hinges a , b and the upper edge 10 of the test body 1 to be welded to the lid 11.
  • the stresses measured in the material hinges a and b are not influenced by the deformations of these sails 13 during the loading of the test body 1.
  • the machining of the test body 1 is made much simpler because of the shape of the central opening 2 and the lateral cavities 12 and the absence of a central beam passing through this central opening 2.
  • the lateral cavities 12 made in the test body 1 can encompass only the area surrounding this single hinge measurement.
  • a bore 14 connects the recess 5 to the housing 8 to pass the son connecting the strain gauges 6, 8 to the electrical circuit 9.
  • Such drilling 14 may be omitted in the case of the embodiment described so far since she does not comprises a cover 11 and the housing 8 communicates with the recess 5. This drilling is essential only in the embodiments where the recess 5 and the housing 8 do not communicate and are each closed by a separate cover as 8.
  • a hole 15 connects the housing 8 to the outside of the test body 1 which can be equipped with a sealed cable passage for connecting the electrical circuit 9 to the apparatus located outside the body. test 1.
  • the principle of this sensor is to produce a central recess 2 in the test body 1 whose shape defines four hinges or deformation zones of the parallelogram thus produced.
  • This central recess 2 also determines the thickness of the measurement hinge (s) a, b.
  • the width of these measuring hinges a, b is then determined by the lateral cavities 12 which also determine the thickness of the webs 13 connecting the measuring hinges a, b to the edge of the test body 1 intended to receive a cover 11 welded.
  • a perfect decoupling is thus achieved between the measurement hinge (s) a, b and the zones of the test body intended to be welded to the cover, which makes it possible to produce a sensor. waterproof precise and inexpensive.
  • the second embodiment of the sensor according to the invention illustrated in Figures 9 to 11 comprises a monolithic test body 1 having a central recess 2 having the general shape of an X whose end of each branch has a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1.
  • the two upper ends of the central recess 2 define the position and the thickness of the measuring hinges a, b while the two lower ends of this central recess define the position and the thickness of the measuring hinges c and d.
  • Pairs of cavities 12 are machined on either side of the test body to the right of each hinge a, b, c, d determining the width of these hinges, all of which are measuring hinges, as well as the thickness of the sails 13 connecting these hinges to the adjacent edge of the test body 1, as is the case in the first embodiment for the measuring hinges a, b .
  • the four hinges a, b, c and d are measuring hinges and each of them is surrounded by a pair of lateral cavities 12.
  • test body 1 it comprises on a first face, the upper face here, a recess 5a for accommodating the strain gauges as in the first embodiment and the drilling 14a allows connecting these strain gauges to their associated circuits housed in the housing 8a also opening on the upper face of the test body and having a shoulder 10b.
  • the housing 8a and the recess 5a are closed by separate covers welded to the shoulders 10a, 10b respectively.
  • the underside of the test body comprises a recess 5b housing the strain gauges associated with measurement hinges c and d and a second hole 14b for connecting them to their associated circuits housed in the housing 8a.
  • This housing 8a is connected to the outside of the test body by a passage 15a for receiving a sealed cable passage.
  • the test body can be tested once the recess (s) 5 are closed by their welded lids, then make the necessary adjustments to the corresponding electrical circuits if necessary before closing the housing 8 by its welded cover.
  • the present sensor always comprises a test body in the form of a single deformable parallelogram comprising a central recess 2 traversing transversely the test body and having the general shape of an H or a X.
  • the ends of the branches of the H-shaped or X-shaped central recess 2 have a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1 and parallel to the upper and lower faces of this test body.
  • This form of the central recess 2 makes it possible to form the four hinges of the test body 1, the flexural deformations of at least some of them will be used to act on the strain gauges.
  • the sensor may have one, two, three or four measuring hinges. When it has one or two, these measurement hinges are preferably located on the same side of the test body 1.
  • the central recess 2 determines the position and the thickness of the measuring hinges.
  • the test body also has pairs of lateral cavities 12, the cavities 12 of each pair being located on either side of each measurement hinge and determining the width of said measurement hinges and the thickness of the sails 13 connecting each measurement hinge to one side of the test body.
  • These thin sails 13 allow a decoupling of the edges of the test body 1 with respect to hinges of measurement, so that these edges of the test body do not participate in the deformations of the hinges during bending of the test body.
  • the cover (s) sealingly closing the recesses 5, 5a this has no influence on the stresses measured at the measuring hinges.
  • the housing 8, 8a is located in an area of the test body not undergoing deformation, so that the welding of the cover closing this housing does not influence the measurement either. It is also noted that the machining of the test body is simple, consisting for the most part of milling, which reduces the manufacturing cost of this sensor.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Measurement Of Force In General (AREA)

Abstract

The invention relates to a sealed sensor comprising a test body in the form of a deformable simple parallelogram, characterised in that it includes a one-piece test body (1) having a generally H- or X-shaped central opening (2) that extends through the body (1), the shape of which determines the position of the four hinges (a, b, c, d) of the deformable parallelogram, between the end of each arm of the opening (2) and one face of the test body (1), and the thickness thereof. At least one of the hinges is a measuring hinge located on one side of the test body, the outer face of said body being provided with a recess (5) and a housing (8) in which the strain gauges and the associated electric circuit are disposed respectively. At least one pair of side cavities (12) define therebetween the width of the measuring hinge(s) and the thickness of the sheets of material (13) connecting the side edges of this measuring hinge to the side edges of the test body corresponding to said hinge, such as to prevent strains generated in the measuring hinges from being affected by strains originating from the side edges of the test body (1). At least one metal cover is welded to the test body in order to seal the recess (5) and the housing (8), the latter including a passage to the exterior of the test body intended to receive a sealed raceway.

Description

Capteur étanche à jauges de contrainte Watertight strain gauge sensor
La présente invention a pour objet un capteur de mesure du type comportant un corps d'épreuve monolithique muni de jauges de contrainte fixées sur ce corps d'épreuve dans au moins une de ses zones de déformation élastique sous l'effet d'un effort appliqué audit corps d'épreuve.The present invention relates to a measuring sensor of the type comprising a monolithic test body provided with strain gauges fixed on this test body in at least one of its zones of elastic deformation under the effect of an applied force. audit body.
Généralement le corps d'épreuve est formé d'un barreau déformable monolithique pouvant présenter la forme d'un parallélogramme déformable dont l'une des extrémités est fixée sur un bâti fixe et dont l'autre est agencée de manière à recevoir un plateau sur lequel est placée la charge à mesurer. De tels capteurs sont décrits par exemple dans les documents US 4.150.729, US 4.546.838 ou US 4.107.985.Generally the test body is formed of a monolithic deformable bar which can have the form of a deformable parallelogram whose one end is fixed on a fixed frame and the other is arranged to receive a plate on which is placed the load to measure. Such sensors are described for example in US 4,150,729, US 4,546,838 or US 4,107,985.
La présente invention vise à la réalisation d'un tel capteur qui puisse être utilisé dans un environnement hostile ou corrosif, eau salée, chlorée ou acide, etc., ce qui oblige à protéger les jauges de contrainte pour éviter leur détérioration.The present invention aims at the realization of such a sensor that can be used in a hostile or corrosive environment, salt water, chlorine or acid, etc., which requires to protect the strain gauges to prevent their deterioration.
Généralement les jauges de contrainte sont protégées par un enduit ou film d'une matière résistante aux agents corrosifs. L'expérience montre néanmoins que c'est toujours cette protection qui se dégrade en premier lieu, nécessitant le remplacement du capteur bien que sa partie mécanique, le corps d'épreuve, soit encore intact.Generally the strain gauges are protected by a coating or film of a material resistant to corrosive agents. However, experience shows that it is always this protection that degrades in the first place, requiring the replacement of the sensor although its mechanical part, the test body, is still intact.
On a proposé des capteurs dans lesquels les jauges de contrainte sont enfermées dans des cavités étanches comme cela est décrit par exemple dans le document US 4.488.611. Cette réalisation nécessite toutefois la soudure de couvercles ou d'éléments de protection métalliques sur le corps d'épreuve à proximité immédiate des zones de déformation de celui-ci, pour encapsuler de façon étanche les jauges de contrainte. Cette façon de faire permet une protection durable des jauges de contrainte mais détériore la précision et la fiabilité de la mesure. En effet, le fait de souder ces couvercles ou protections à proximité immédiate des zones de déformation du corps d'épreuve induit des modifications structurelles du matériau constitutif du corps d'épreuve dans ces zones modifiant notamment ses caractéristiques élastiques qui sont la source d'imprécisions ou d'erreurs de mesure ne pouvant pas être aisément corrigées électriquement.Sensors have been proposed in which the strain gauges are enclosed in sealed cavities as described, for example, in US Pat. No. 4,488,611. This embodiment, however, requires the welding of covers or metal protective elements on the test body in the immediate vicinity of the deformation zones thereof, to encapsulate sealingly the strain gauges. This way of doing things allows long-term protection of the strain gauges but deteriorates the accuracy and reliability of the measurement. Indeed, the fact of welding these covers or protections in the immediate vicinity of the deformation zones of the test body induces modifications structural elements of the material constituting the test body in these areas including changing its elastic characteristics which are the source of inaccuracies or measurement errors that can not be easily corrected electrically.
En outre ces capteurs étanches nécessitent une poutre de mesure distincte des deux bras du parallélogramme déformable du corps d'épreuve, généralement placée dans l'évidement central de ce corps d'épreuve, ce qui complique son usinage et renchérit donc fortement le capteur étanche.In addition these sealed sensors require a measurement beam separate from the two arms of the deformable parallelogram of the test body, generally placed in the central recess of this test body, which complicates its machining and thus greatly increases the sealed sensor.
La titulaire a développé un capteur étanche décrit dans le document EP- 1319931 dans lequel les jauges de contrainte et leur circuit électrique associé sont placés dans une cavité du corps d'épreuve dont les bords devant être obturés par une plaque soudée sont situés dans une zone du corps d'épreuve ne participant pas à la mesure, ces bords étant découplés notamment de la poutre de mesure. Toutefois ici également le corps d'épreuve comporte une poutre principale, reliée à la poutre de mesure, distincte des côtés du parallélogramme déformable et traversant la cavité centrale du corps d'épreuve dont l'usinage reste complexe et onéreux.The licensee has developed a leakproof sensor described in EP-1319931 in which the strain gauges and their associated electrical circuit are placed in a cavity of the test body whose edges to be closed by a welded plate are located in a zone of the test body not participating in the measurement, these edges being decoupled in particular from the measuring beam. However here also the test body comprises a main beam, connected to the measuring beam, distinct from the sides of the deformable parallelogram and through the central cavity of the test body whose machining remains complex and expensive.
Le but de la présente invention est la réalisation d'un capteur étanche à jauges de contrainte dans lequel, d'une part, les cavités recevant les jauges de contrainte et leur circuit électrique associé sont disposées de manière que leurs bords destinés à être reliés par soudure à un couvercle métallique soient éloignés et découplés mécaniquement des zones de déformation servant à la mesure et, d'autre part, dont le corps d'épreuve en forme de parallélogramme déformable présente un usinage simple et notamment ne comporte pas de poutre traversant la cavité centrale de ce corps d'épreuve, de telle manière que l'on obtienne un capteur précis et meilleur marché.The object of the present invention is the production of a strain-gage-proof sensor in which, on the one hand, the cavities receiving the strain gauges and their associated electrical circuit are arranged in such a way that their edges intended to be connected by welding to a metal cover are remote and mechanically decoupled from the deformation zones used for the measurement and, secondly, whose test body in the form of deformable parallelogram has a simple machining and in particular does not include a beam passing through the cavity central of this test body, so that we obtain a precise and cheaper sensor.
Ainsi la présente invention a pour but la réalisation d'un capteur comportant un corps d'épreuve monolithique et des jauges de contrainte encapsulées, donc protégées de l'environnement, qui obvie aux inconvénients précités c'est-à-dire qui est résistant, dont la protection des jauges n'influence pas les caractéristiques de mesure et qui soit d'un moindre coût de fabrication.Thus, the purpose of the present invention is to provide a sensor comprising a monolithic proof body and encapsulated strain gauges, thus protected from the environment, which obviates the aforementioned drawbacks, that is to say which is resistant, the protection of gauges does not influence the measurement characteristics and is a lower cost of manufacture.
La présente invention a pour objet un capteur de mesure étanche comportant un corps d'épreuve monolithique muni de jauges de contrainte qui se distingue par les caractéristiques énumérées à la revendication indépendante 1. Les modes particuliers de réalisation de l'invention sont définis dans les revendications dépendantes.The present invention relates to a sealed measuring sensor comprising a monolithic proof body provided with strain gauges which is distinguished by the characteristics listed in the independent claim 1. The particular embodiments of the invention are defined in the claims dependent.
Le dessin annexé illustre schématiquement et à titre d'exemple deux formes d'exécution du capteur selon l'invention. La figure 1 est une vue en perspective du capteur sans son couvercle d'obturation.The accompanying drawing illustrates schematically and by way of example two embodiments of the sensor according to the invention. Figure 1 is a perspective view of the sensor without its closure cap.
La figure 2 est une vue en plan de dessus du capteur illustré à la figure 1.Figure 2 is a top plan view of the sensor shown in Figure 1.
La figure 3 est une vue en plan de dessous du capteur illustré à la figure 1.Figure 3 is a bottom plan view of the sensor shown in Figure 1.
La figure 4 est une vue de côté du capteur illustré à la figure 1. La figure 5 est une coupe suivant la ligne A-A de la figure 4.FIG. 4 is a side view of the sensor illustrated in FIG. 1. FIG. 5 is a section along the line A-A of FIG. 4.
La figure 6 est un détail à plus grande échelle de la figure 5.Figure 6 is an enlarged detail of Figure 5.
La figure 7 est une vue en perspective du capteur illustré à la figure 1 , son couvercle d'obturation étant soudé en place sur le corps d'épreuve.Figure 7 is a perspective view of the sensor shown in Figure 1, its closure cap being welded in place on the test body.
La figure 8 est une vue de dessus d'une seconde forme d'exécution du capteur.Figure 8 is a top view of a second embodiment of the sensor.
La figure 9 est une vue de côté du capteur illustré à la figure 8.Figure 9 is a side view of the sensor shown in Figure 8.
La figure 10 est une vue de dessous du capteur illustré à la figure 8.Figure 10 is a bottom view of the sensor shown in Figure 8.
La figure 11 est une représentation en perspective du capteur selon la seconde forme d'exécution. La présente invention a pour objet un capteur de pesage étanche à jauges de contrainte du type à simple parallélogramme. Pour réaliser le but proposé on utilise un corps d'épreuve de type parallélogramme déformable afin d'accepter les excentrations de charge. Ce capteur ne comporte pas, comme il est généralement d'usage, de troisième poutre complémentaire traversant l'ouverture du parallélogramme, ceci afin de simplifier au maximum l'usinage du corps d'épreuve et réduire ainsi le prix de revient de celui-ci. Ce corps d'épreuve est formé d'un parallélogramme constitué de quatre charnières dont au moins une mais de préférence deux ont une forme particulière caractérisée par une partie centrale étroite reliée de part et d'autre par un voile très fin (0.1 à 0.4mm) aux deux parties extérieures suffisamment épaisses pour supporter la soudure de la feuille métallique de fermeture et former ainsi une cavité étanche accueillant les jauges et assurant ainsi leur protection vis-à-vis de l'environnement extérieur agressif. Les parties centrales étroites (4 à 8mm) appelées charnières sont constituées d'une section de matière comprise entre la partie plate où sont collées les jauges de contrainte et la face concave (rayon de 6mm) de telle façon que les déformations soient limitées à ces seules zones amincies constituant ainsi un parallélogramme présentant une assez grande raideur.Figure 11 is a perspective representation of the sensor according to the second embodiment. The subject of the present invention is a strain-gage-type weighing sensor of the single parallelogram type. To achieve the proposed purpose, a deformable parallelogram proof body is used to accept the load eccentricities. This sensor does not have, as is generally the case, a third complementary beam passing through the opening of the parallelogram, in order to simplify as much as possible the machining of the test body and thus reduce the cost price thereof. This test body is formed of a parallelogram consisting of four hinges of which at least one but preferably two have a particular shape characterized by a narrow central portion connected on both sides by a very thin veil (0.1 to 0.4mm ) to the two outer parts sufficiently thick to support the welding of the metal closure sheet and thus form a sealed cavity accommodating the gauges and thus providing protection vis-à-vis the aggressive outdoor environment. The narrow central parts (4 to 8mm) called hinges consist of a section of material between the flat part where the strain gauges are bonded and the concave face (radius of 6mm) so that the deformations are limited to these only thinned zones thus constituting a parallelogram having a fairly high stiffness.
A l'opposé, les voiles de liaison des charnières aux parties extérieures sont conçus de façon à présenter grâce à leur forme et leur faible épaisseur le maximum de souplesse possible afin de découpler parfaitement le parallélogramme de mesure des parties extérieures qui assurent en association avec la plaque de fermeture l'étanchéité de l'ensemble.In contrast, the connecting webs of the hinges to the outer parts are designed so as to present, thanks to their shape and their small thickness, the maximum possible flexibility in order to perfectly decouple the parallelogram of measurement of the external parts which ensure in association with the closing plate sealing the assembly.
En se référant aux figures 1 à 7 du dessin on voit que le capteur de mesure selon la présente invention comporte un corps d'épreuve monolithique 1 constituant un parallélogramme déformable en acier, acier inoxydable ou alliage de ceux-ci, aluminium ou autre matériau élastique, dont une extrémité 1a est destinée à être fixée sur un bâti tandis que l'autre extrémité 1b est équipée pour recevoir un plateau sur lequel est posée une charge à peser ou appliquée une force à mesurer. Ce corps d'épreuve (voir figure 4) est traversé transversalement par un évidement central 2 présentant la forme générale d'un H définissant les quatre charnières a, b, c, d du parallélogramme déformable dont au moins une (a) est une charnière de mesure (voir figure 6). Chaque extrémité des branches verticales du H que forme l'évidement central 2 présente une forme cylindrique dont les génératrices sont perpendiculaires à l'axe longitudinal du corps d'épreuve 1.With reference to FIGS. 1 to 7 of the drawing, it can be seen that the measuring sensor according to the present invention comprises a monolithic proof body 1 constituting a deformable parallelogram made of steel, stainless steel or alloy thereof, aluminum or other elastic material. , one end 1a is intended to be fixed on a frame while the other end 1b is equipped to receive a tray on which is placed a load to be weighed or applied a force to be measured. This test body (see FIG. 4) is traversed transversely by a central recess 2 having the general shape of an H defining the four hinges a, b, c, d of the deformable parallelogram of which at least one (a) is a hinge measurement (see Figure 6). Each end of the vertical branches of the H that forms the central recess 2 has a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1.
Les deux charnières inférieures c, d servant à la déformation du corps d'épreuve mais non à la mesure présentent une faible épaisseur et peuvent encore être affaiblies par des ouvertures 3, 4 pratiquées dans la paroi inférieure du corps d'épreuve 1. Ceci est plus particulièrement utile dans le cas de corps d'épreuve pour de faibles charges nominales.The two lower hinges c, d serving to deform the test body but not to the measurement are thin and can be further weakened by openings 3, 4 made in the lower wall of the test body 1. This is more particularly useful in the case of test bodies for low nominal loads.
Les charnières inférieures c et d présentent une épaisseur de l'ordre de 0,5mm à 1mm par exemple, dépendant de la charge nominale du capteur. Les charnières supérieures a, b constituent les parties du corps d'épreuve qui non seulement vont assurer la déformabilité du corps d'épreuve mais qui sont utilisées pour mesurer les contraintes de flexion qui vont être mesurées à l'aide de jauges de contrainte. Ces charnières de mesure a, b, dans certaines variantes une seule de ces charnières sert à la mesure, présentent une épaisseur plus importante, de l'ordre de 1 mm à 2mm par exemple, dépendant également de la charge nominale du capteur. Les chiffres indiqués ci-dessus sont valables pour des capteurs prévus pour une charge nominale de 5 à 10 kilogrammes et comme indiqué ci-dessus peuvent varier en fonction de la charge nominale du capteur envisagé. Plus la charge nominale est grande, pouvant aller jusqu'à quelques centaines de kilogrammes, plus les charnières sont épaisses.The lower hinges c and d have a thickness of the order of 0.5mm to 1mm for example, depending on the nominal load of the sensor. The upper hinges a, b are those parts of the proof body which not only will ensure the deformability of the test body but are used to measure the bending stresses that will be measured using strain gauges. These measurement hinges a, b, in some variants only one of these hinges is used for measurement, have a greater thickness, of the order of 1 mm to 2 mm for example, also depending on the nominal load of the sensor. The figures given above are valid for sensors rated for a nominal load of 5 to 10 kilograms and as indicated above may vary depending on the rated load of the intended sensor. The higher the rated load, up to a few hundred kilograms, the heavier the hinges.
La face supérieure du corps d'épreuve 1 comporte d'une part une creusure 5 de faible profondeur destinée à recevoir des jauges de contrainte 6,7 fixées sur le fond de cette creusure 5 au droits des charnières de mesure a, b et, d'autre part un logement plus profond 8 destiné à loger les circuits électriques 9 associés aux jauges de contrainte 6,7. Cette creusure 5 et ce logement 8 présentent un rebord 10 situé dans un même plan, parallèle à la face supérieure du corps d'épreuve 1. Ce rebord 10 permet de positionner une plaque de fermeture ou couvercle 11 recouvrant et obturant la creusure 5 et le logement 8 qui sera soudée par exemple au laser sur ledit rebord 10 pour assurer une étanchéité parfaite de Ia creusure 5 et du logement 8.The upper face of the test body 1 comprises on the one hand a shallow recess 5 intended to receive strain gauges 6.7 fixed on the bottom of this recess 5 to the right of the measurement hinges a, b and, d on the other hand, a deeper housing 8 intended to house the electrical circuits 9 associated with the strain gauges 6, 7. This recess 5 and this housing 8 have a flange 10 located in the same plane, parallel to the upper face of the test body 1. This flange 10 allows to position a closure plate or cover 11 covering and closing the recess 5 and the housing 8 which will be welded for example laser on said flange 10 to ensure perfect sealing of the recess 5 and the housing 8.
Pour être certain que la zone du corps d'épreuve 1 située autour de la creusure 5 ne participe pas à la mesure, ces zones pouvant être affectées en ce qui concerne les caractéristiques de la matière par la soudure du couvercle 11 , des paires de cavités latérales 12 sont usinées de part et d'autre du corps d'épreuve délimitant une largeur des charnières a, b servant à la mesure, de l'ordre de 4 à 8mm pour des corps d'épreuve de capacité nominale de 5 à 10 kilogrammes. Ces paires de cavités latérales définissent également l'épaisseur des voiles 13 reliant les charnières a, b aux bords correspondants du corps d'épreuve 1.To be certain that the zone of the test body 1 situated around the hollow 5 does not participate in the measurement, these zones being able to be affected as regards the characteristics of the material by the welding of the cover 11, pairs of cavities 12 are machined on both sides of the test body delimiting a width of the hinges a, b used for the measurement, of the order of 4 to 8mm for test bodies of nominal capacity of 5 to 10 kilograms . These pairs of lateral cavities also define the thickness of the webs 13 connecting the hinges a, b to the corresponding edges of the test body 1.
Ainsi la matière du corps d'épreuve 1 qui est utilisée pour la mesure des contraintes est limitée aux charnières de mesure a et b présentant une épaisseur et une largeur bien déterminées. Les voiles 13 de matière reliant la charnière a, respectivement b, aux bords latéraux supérieurs du corps d'épreuve 1 sont de faible épaisseur, de l'ordre de 0,1mm à 0,4mm, et assurent un total découplage entre les charnières a, b et le bord supérieur 10 du corps d'épreuve 1 devant être soudé au couvercle 11. De ce fait on peut garantir que les contraintes que l'on mesure dans la matière des charnières a et b ne sont pas influencées par les déformations de ces voiles 13 lors de Ia mise en charge du corps d'épreuve 1.Thus, the material of the test body 1 which is used for the measurement of the stresses is limited to the measuring hinges a and b having a specific thickness and width. The sails 13 of material connecting the hinge has, respectively b, to the upper lateral edges of the test body 1 are thin, of the order of 0.1mm to 0.4mm, and ensure a total decoupling between the hinges a , b and the upper edge 10 of the test body 1 to be welded to the lid 11. Thus it can be ensured that the stresses measured in the material hinges a and b are not influenced by the deformations of these sails 13 during the loading of the test body 1.
D'autre part, l'usinage du corps d'épreuve 1 est rendu beaucoup plus simple du fait de la forme de l'ouverture centrale 2 et des cavités latérales 12 et de l'absence de poutre médiane traversant cette ouverture centrale 2.On the other hand, the machining of the test body 1 is made much simpler because of the shape of the central opening 2 and the lateral cavities 12 and the absence of a central beam passing through this central opening 2.
Dans le cas où seule l'une des charnières a, b supérieure est utilisée pour la mesure, les cavités latérales 12 pratiquées dans le corps d'épreuve 1 peuvent n'englober que la zone environnant cette unique charnière de mesure.In the case where only one of the upper hinges b is used for the measurement, the lateral cavities 12 made in the test body 1 can encompass only the area surrounding this single hinge measurement.
Un perçage 14 relie la creusure 5 au logement 8 pour faire passer les fils reliant les jauges de contrainte 6, 8 au circuit électrique 9. Un tel perçage 14 peut être omis dans le cas de la forme d'exécution décrite jusqu'ici puisqu'elle ne comporte qu'un couvercle 11 et que le logement 8 communique avec la creusure 5. Ce perçage n'est indispensable que dans les formes d'exécution où la creusure 5 et le logement 8 ne communiquent pas et sont chacun obturés par un couvercle distinct comme illustré à la figure 8. Enfin, un trou 15 relie le logement 8 à l'extérieur du corps d'épreuve 1 qui peut être équipé d'un passage de câble étanche pour relier le circuit électrique 9 à l'appareillage situé hors du corps d'épreuve 1.A bore 14 connects the recess 5 to the housing 8 to pass the son connecting the strain gauges 6, 8 to the electrical circuit 9. Such drilling 14 may be omitted in the case of the embodiment described so far since she does not comprises a cover 11 and the housing 8 communicates with the recess 5. This drilling is essential only in the embodiments where the recess 5 and the housing 8 do not communicate and are each closed by a separate cover as 8. Finally, a hole 15 connects the housing 8 to the outside of the test body 1 which can be equipped with a sealed cable passage for connecting the electrical circuit 9 to the apparatus located outside the body. test 1.
Le principe de ce capteur est de réaliser un évidement central 2 dans le corps d'épreuve 1 dont la forme définit quatre charnières ou zones de déformation du parallélogramme ainsi réalisé. Cet évidement central 2 détermine également l'épaisseur de la ou des charnières de mesure a, b. La largeur de ces charnières de mesure a, b est ensuite elle déterminée par les cavités latérales 12 qui déterminent également l'épaisseur des voiles 13 reliant les charnières de mesure a, b au bord du corps d'épreuve 1 destiné à recevoir un couvercle 11 soudé. On réalise ainsi avec un minimum d'usinage du corps d'épreuve 1 un découplage parfait entre Ia ou les charnières de mesure a, b et les zones du corps d'épreuve destinées à être soudées au couvercle, ce qui permet de réaliser un capteur étanche précis et peu onéreux.The principle of this sensor is to produce a central recess 2 in the test body 1 whose shape defines four hinges or deformation zones of the parallelogram thus produced. This central recess 2 also determines the thickness of the measurement hinge (s) a, b. The width of these measuring hinges a, b is then determined by the lateral cavities 12 which also determine the thickness of the webs 13 connecting the measuring hinges a, b to the edge of the test body 1 intended to receive a cover 11 welded. With a minimum of machining of the test body 1, a perfect decoupling is thus achieved between the measurement hinge (s) a, b and the zones of the test body intended to be welded to the cover, which makes it possible to produce a sensor. waterproof precise and inexpensive.
La seconde forme d'exécution du capteur selon l'invention illustrée aux figures 9 à 11 comporte un corps d'épreuve monolithique 1 comportant un évidement central 2 présentant la forme générale d'un X dont l'extrémité de chaque branche présente une forme cylindrique dont les génératrices sont perpendiculaires à l'axe longitudinal du corps d'épreuve 1.The second embodiment of the sensor according to the invention illustrated in Figures 9 to 11 comprises a monolithic test body 1 having a central recess 2 having the general shape of an X whose end of each branch has a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1.
Les deux extrémités supérieures de l'évidement central 2 définissent la position et l'épaisseur des charnières de mesure a, b tandis que les deux extrémités inférieures de cet évidement central définissent la position et l'épaisseur des charnières de mesure c et d.The two upper ends of the central recess 2 define the position and the thickness of the measuring hinges a, b while the two lower ends of this central recess define the position and the thickness of the measuring hinges c and d.
Des paires de cavités 12 sont usinées de part et d'autre du corps d'épreuve au droit de chaque charnière a, b, c, d déterminant la largeur de ces charnières, qui toutes sont des charnières de mesure, ainsi que l'épaisseur des voiles 13 reliant ces charnières au bord adjacent du corps d'épreuve 1 , comme c'est le cas dans la première forme d'exécution pour les charnières de mesure a, b. Dans cette forme d'exécution les quatre charnières a, b, c et d sont des charnières de mesure et chacune d'elles est entourée par une paire de cavités latérales 12.Pairs of cavities 12 are machined on either side of the test body to the right of each hinge a, b, c, d determining the width of these hinges, all of which are measuring hinges, as well as the thickness of the sails 13 connecting these hinges to the adjacent edge of the test body 1, as is the case in the first embodiment for the measuring hinges a, b . In this embodiment the four hinges a, b, c and d are measuring hinges and each of them is surrounded by a pair of lateral cavities 12.
Dans cette seconde forme d'exécution du corps d'épreuve 1 celui-ci comporte sur une première face, la face supérieure ici, une creusure 5a permettant de loger les jauges de contrainte comme dans la première forme d'exécution et le perçage 14a permet de relier ces jauges de contrainte à leurs circuits associés logés dans le logement 8a débouchant également sur la face supérieure du corps d'épreuve et comportant un épaulement 10b. Le logement 8a et la creusure 5a sont obturés par des couvercles distincts soudés sur les épaulements 10a, 10b respectivement.In this second embodiment of the test body 1 it comprises on a first face, the upper face here, a recess 5a for accommodating the strain gauges as in the first embodiment and the drilling 14a allows connecting these strain gauges to their associated circuits housed in the housing 8a also opening on the upper face of the test body and having a shoulder 10b. The housing 8a and the recess 5a are closed by separate covers welded to the shoulders 10a, 10b respectively.
Dans cette forme d'exécution la face inférieure du corps d'épreuve comporte une creusure 5b logeant les jauges de contrainte associées aux charnières de mesure c et d et un second perçage 14b permettant de les relier à leurs circuits associés logés dans le logement 8a. Ce logement 8a est relié à l'extérieur du corps d'épreuve par un passage 15a destiné à recevoir un passage de câble étanche. Dans cette forme d'exécution, et dans toutes celles comportant des couvercles distincts pour la creusure 5 logeant les jauges de contrainte et le logement 8 renfermant les circuits électriques, on peut tester le corps d'épreuve une fois que la ou les creusures 5 sont obturées par leurs couvercles soudés, puis apporter les réglages nécessaires aux circuits électriques correspondants si nécessaire avant d'obturer le logement 8 par son couvercle soudé. La soudure du couvercle du logement 8 ne modifie plus les caractéristiques du corps d'épreuve 1 puisque ce logement se situe dans une portion non déformable du corps d'épreuve. On peut ainsi encore améliorer la précision et la linéarité de la réponse électrique du capteur aux charges qu'il mesure. Comme on l'a vu de ce qui précède le présent capteur comporte toujours un corps d'épreuve en forme de simple parallélogramme déformable monobloc comprenant un évidement central 2 traversant transversalement le corps d'épreuve et présentant la forme générale d'un H ou d'un X. Les extrémités des branches de l'évidement central 2 en forme de H ou de X présentent une forme cylindrique dont les génératrices sont perpendiculaires à l'axe longitudinal du corps d'épreuve 1 et parallèles aux faces supérieure et inférieure de ce corps d'épreuve. Cette forme de l'évidement central 2 permet de constituer les quatre charnières du corps d'épreuve 1 dont les déformations de flexion d'au moins certaines d'entre elles seront utilisées pour agir sur les jauges de contrainte.In this embodiment, the underside of the test body comprises a recess 5b housing the strain gauges associated with measurement hinges c and d and a second hole 14b for connecting them to their associated circuits housed in the housing 8a. This housing 8a is connected to the outside of the test body by a passage 15a for receiving a sealed cable passage. In this embodiment, and in all those having separate covers for the recess 5 housing the strain gauges and the housing 8 enclosing the electrical circuits, the test body can be tested once the recess (s) 5 are closed by their welded lids, then make the necessary adjustments to the corresponding electrical circuits if necessary before closing the housing 8 by its welded cover. The welding of the housing cover 8 no longer modifies the characteristics of the test body 1 since this housing is located in a non-deformable portion of the test body. It is thus possible to further improve the accuracy and linearity of the electrical response of the sensor to the loads it measures. As has been seen from the foregoing, the present sensor always comprises a test body in the form of a single deformable parallelogram comprising a central recess 2 traversing transversely the test body and having the general shape of an H or a X. The ends of the branches of the H-shaped or X-shaped central recess 2 have a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the test body 1 and parallel to the upper and lower faces of this test body. This form of the central recess 2 makes it possible to form the four hinges of the test body 1, the flexural deformations of at least some of them will be used to act on the strain gauges.
Le capteur peut comporter une, deux, trois ou quatre charnières de mesure. Lorsqu'il en comporte une ou deux, ces charnières de mesure sont de préférence situées d'un même côté du corps d'épreuve 1.The sensor may have one, two, three or four measuring hinges. When it has one or two, these measurement hinges are preferably located on the same side of the test body 1.
L'évidement central 2 détermine la position et l'épaisseur des charnières de mesure.The central recess 2 determines the position and the thickness of the measuring hinges.
Le corps d'épreuve comporte encore des paires de cavités latérales 12, les cavités 12 de chaque paire étant situées de part et d'autre de chaque charnière de mesure et déterminant la largeur des dites charnières de mesure et l'épaisseur des voiles 13 reliant chaque charnière de mesure à un côté du corps d'épreuve. Ces voiles 13 minces permettent un découplage des bords du corps d'épreuve 1 par rapport aux charnières de mesure, de sorte que ces bords du corps d'épreuve ne participent pas aux déformations des charnières lors de la flexion du corps d'épreuve. Ainsi, même si les caractéristiques élastiques de la matière des bords supérieur et inférieur du corps d'épreuve sont modifiées par la soudure du ou des couvercles obturant de façon étanche les creusures 5, 5a, cela n'a aucune influence sur les contraintes mesurées aux charnières de mesure.The test body also has pairs of lateral cavities 12, the cavities 12 of each pair being located on either side of each measurement hinge and determining the width of said measurement hinges and the thickness of the sails 13 connecting each measurement hinge to one side of the test body. These thin sails 13 allow a decoupling of the edges of the test body 1 with respect to hinges of measurement, so that these edges of the test body do not participate in the deformations of the hinges during bending of the test body. Thus, even if the elastic characteristics of the material of the upper and lower edges of the test body are modified by the welding of the cover (s) sealingly closing the recesses 5, 5a, this has no influence on the stresses measured at the measuring hinges.
Enfin, le logement 8, 8a est situé dans une zone du corps d'épreuve ne subissant pas de déformation, de sorte que la soudure du couvercle obturant ce logement n'influence pas non plus la mesure. On remarque encore que l'usinage du corps d'épreuve est simple, constitué pour l'essentiel de fraisages, ce qui permet de réduire le coût de fabrication de ce capteur. Finally, the housing 8, 8a is located in an area of the test body not undergoing deformation, so that the welding of the cover closing this housing does not influence the measurement either. It is also noted that the machining of the test body is simple, consisting for the most part of milling, which reduces the manufacturing cost of this sensor.

Claims

Revendications claims
1. Capteur étanche à jauges de contrainte du type à corps d'épreuve en forme de simple parallélogramme déformable destiné à recevoir un plateau de charge, caractérisé par le fait qu'il comporte un corps d'épreuve monobloc (1) comportant un évidement central (2) présentant la forme générale d'un H ou d'un X traversant transversalement ce corps d'épreuve (1) et dont la forme définit la position des quatre charnières (a, b, c, d) du parallélogramme déformable se situant entre l'extrémité de chaque branche de l'évidement (2) et une face du corps d'épreuve (1) et leur épaisseur ; au moins une de ces charnières étant une charnière de mesure située sur un côté du parallélogramme déformable du corps d'épreuve comportant sur sa face extérieure une creusure (5) et un logement (8) dans lesquels sont disposés respectivement les jauges de contrainte et leur circuit électrique associé; au moins une paire de cavités latérales (12) définissant entre elles la largeur de la ou des charnières de mesure et l'épaisseur des voiles de matière (13) reliant les bords latéraux de cette charnière de mesure aux bords latéraux du corps d'épreuve correspondant à cette charnière, de manière à éviter que les contraintes provoquées dans les charnières de mesure ne soient affectées par des contraintes provenant desdits bords latéraux du corps d'épreuve (1); et par le fait qu'au moins un couvercle métallique est soudé sur le corps d'épreuve pour en obturer de façon étanche la creusure (5) et le logement (8), ce dernier comportant un passage le reliant à l'extérieur du corps d'épreuve destiné à recevoir un passage de câbles étanche.1. Strain-proof type strain-proof sensor in the form of a simple deformable parallelogram for receiving a load plate, characterized in that it comprises a one-piece proof body (1) comprising a central recess (2) having the general shape of an H or an X traversing transversely this test body (1) and whose shape defines the position of the four hinges (a, b, c, d) of the deformable parallelogram lying between the end of each branch of the recess (2) and a face of the test body (1) and their thickness; at least one of these hinges being a measurement hinge located on one side of the deformable parallelogram of the test body comprising on its outer face a recess (5) and a housing (8) in which the strain gauges are respectively arranged and their associated electrical circuit; at least one pair of lateral cavities (12) defining between them the width of the measurement hinge (s) and the thickness of the material webs (13) connecting the lateral edges of this measuring hinge to the lateral edges of the test body corresponding to this hinge, so as to avoid that the stresses caused in the measuring hinges are affected by stresses coming from said lateral edges of the test body (1); and in that at least one metal cover is welded to the test body to sealingly seal the recess (5) and the housing (8), the latter having a passage connecting it to the outside of the body test piece for receiving a sealed cable passage.
2. Capteur étanche selon la revendication 1 , caractérisé par le fait que les extrémités des branches de l'évidement (2) central en forme de H ou de X présentent une forme cylindrique dont les génératrices sont perpendiculaires à l'axe longitudinal du corps d'épreuve et parallèles aux faces supérieure et inférieure du corps d'épreuve.2. Sealed sensor according to claim 1, characterized in that the ends of the branches of the recess (2) central H-shaped or X have a cylindrical shape whose generatrices are perpendicular to the longitudinal axis of the body of and parallel to the upper and lower faces bottom of the test body.
3. Capteur étanche selon la revendication 1 ou la revendication 2, caractérisé par le fait que les cavités d'une paire de cavités latérales (12)sont disposées de part et d'autre d'au moins une charnière de mesure.3. Sealed sensor according to claim 1 or claim 2, characterized in that the cavities of a pair of lateral cavities (12) are arranged on either side of at least one measuring hinge.
4. Capteur étanche selon la revendication 3, caractérisé par le fait que les cavités d'une paire de cavités latérales (12) sont disposées de part et d'autre de deux charnières de mesure situées sur une même face du corps d'épreuve.4. Sealed sensor according to claim 3, characterized in that the cavities of a pair of lateral cavities (12) are arranged on either side of two measuring hinges located on the same face of the test body.
5. Capteur étanche selon l'une des revendications 1 à 3, caractérisé par le fait qu'il comporte deux charnières de mesure (a, b) proches de la surface supérieure du corps d'épreuve (1).5. Sealed sensor according to one of claims 1 to 3, characterized in that it comprises two measuring hinges (a, b) close to the upper surface of the test body (1).
6. Capteur étanche selon l'une des revendications 1 à 4, caractérisé par le fait qu'il comporte deux charnières de mesure (c, d) proches de la surface inférieure du corps d'épreuve (1).6. Sealed sensor according to one of claims 1 to 4, characterized in that it comprises two measuring hinges (c, d) close to the lower surface of the test body (1).
7. Capteur selon la revendication 6, caractérisé par le fait qu'il comporte une seconde creusure (5a) dans la face inférieure du corps d'épreuve (1).7. Sensor according to claim 6, characterized in that it comprises a second recess (5a) in the lower face of the test body (1).
8. Capteur étanche selon l'une des revendications précédentes, caractérisé par le fait qu'il comporte au moins une jauge de contrainte (6, 7) fixée sur le fond de la creusure (5) en regard d'une charnière de mesure.8. Sealed sensor according to one of the preceding claims, characterized in that it comprises at least one strain gauge (6, 7) fixed on the bottom of the recess (5) facing a measuring hinge.
9. Capteur étanche selon la revendication 8, caractérisé par le fait qu'il comporte une jauge de contrainte fixée sur le fond des creusures (5, 5a) en regard de chaque charnière de mesure (a, b, c, d). _9. Sealed sensor according to claim 8, characterized in that it comprises a strain gauge fixed on the bottom of the recesses (5, 5a) facing each measurement hinge (a, b, c, d). _
1313
10. Capteur selon l'une des revendications précédentes, caractérisé par le fait qu'il comporte deux couvercles distincts obturant l'un le logement (8) et l'autre la creusure (5).10. Sensor according to one of the preceding claims, characterized in that it comprises two separate covers closing one the housing (8) and the other the recess (5).
11. Capteur selon la revendication 10, caractérisé par le fait qu'il comporte un troisième couvercle obturant la creusure (5a) de la face inférieure du corps d'épreuve (1). 11. The sensor of claim 10, characterized in that it comprises a third cover closing the recess (5a) of the underside of the test body (1).
EP09824254A 2009-03-19 2009-03-19 Sealed sensor with strain gauges Withdrawn EP2409122A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IB2009/000563 WO2010106388A1 (en) 2009-03-19 2009-03-19 Sealed sensor with strain gauges

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EP2409122A1 true EP2409122A1 (en) 2012-01-25

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WO (1) WO2010106388A1 (en)

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JP6124342B2 (en) * 2013-09-25 2017-05-10 大和製衡株式会社 Load cell
JP6120120B2 (en) 2014-06-11 2017-04-26 アーゲ ジュール アイラーセン，ニルス High precision load cell with elastic body
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JP6955364B2 (en) * 2017-04-18 2021-10-27 大和製衡株式会社 Load cell
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WO2010106388A1 (en) 2010-09-23
US8561482B2 (en) 2013-10-22
CA2747851A1 (en) 2010-09-23
US20110232393A1 (en) 2011-09-29

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