Abstract: A measurement transformer has a pressure chamber which is sealed off by a membrane (2). On the membrane (2) there is seated a ram (16) which rests against a central part (7) of a spring plate (6). The central part (7) is connected by means of two flexural beam sections (9, 10) with the edge of the spring plate (6). Furthermore, web sections (13, 14, 15) connect the central part (7) to the edge part (8). For the adjustment of the measurement transformer the web sections (13, 14, 15) can be cut through. The more web sections (13, 14, 15) are cut through, the easier it is for the central part (7) to be displaced relative to the edge part (8). Wire strain gauges (11, 12) on the beam sections (9, 10) register this displacement.

Abstract: A pressure transducer (10; 10') having a silicon diaphragm (14; 14') and an insulating glass base (11; 11'). Surfaces (16, 12; 16', 12') of the diaphragm and glass base are anodically bonded together to form a hermetic seal for an internal reference cavity (24; 24') therein and also to provide hermetic protection for critical areas (70, 77; 70', 80, 81) on the silicon diaphragm. A plurality of semiconductor components are synthesized in an area (70; 70') in the silicon diaphragm. A plurality of conductors (71-73; 71'-73') are embedded (sealed) in the glass base so as to provide external electrical access to the semiconductor components without disrupting the hermetic seal provided between the silicon diaphragm and the glass base.

Abstract: A high temperature transducer consists of a first section having a base layer of monocrystalline silicon which layer is coated with an oxide. A thin layer of a high temperature glass is sputtered on the oxide layer of the base layer. A second section is formed by diffusing a wafer of N type silicon to form a p+ layer. The first and second sections are bonded together by an anodic bond where the p+ layer is secured to the glass layer to form a composite structure. The N type material is then removed and piezoresistive deivces are formed in the p+ layer. This structure provides a high temperature transducer which exhibits stable operating parameters over a wide operating range.

Abstract: Differential transducers for corrosive or electrically conductive fluids have a first tube for guiding such fluids toward one side of a semiconductor diaphragm containing embedded strain gages, and a second tube for guiding such fluids toward an opposite side of that semiconductor diaphragm. These tubes are made of an electrically insulating material temporarily convertible to an electrical conductor for electrostatic bonding. The semiconductor diaphragm is provided in a semiconductor wafer extending beyond the perimeter of at least the first tube. The strain gages are provided with embedded electrical leads extending beyond the above mentioned perimeter for attachment of electrical contact wires outside the first tube, while providing these leads inlaid in the semiconductor wafer at least in a region to be covered by the first tube.

Abstract: Column-type load cells having recessed portions on opposite sides to receive strain gauges mounted on the web in the recesses for more linear response are improved by reduced cross sections off each end of the recesses, and/or by flexures off each end, with adjustment of the diameter of the reduced diameter portions and the distances of the flexures from the recesses to adjust the linearization effect of the recesses. Diaphragms arranged either at one end or both ends are used to support a tube cover. Utilizing two diaphragms, one at each end of a tube cover has been found to improve linearization even without reduced cross sections and/or flexures.

Abstract: A force measuring cell has a force sensor in the form of a bendable support. The base part and the load-receiving element of the force sensor are connected by two elastically bendable link members with pronounced bendable segments. Strain gauge elements in the form of strips are disposed on the bendable segments of one of the link members, to produce an electrical signal corresponding to the force (F) being measured. In order to achieve uniformity of the magnitudes of the stresses on all the bendable segments when under load, the mean material thickness of the bendable segments of the link member, which bendable segments are disposed closest to the base part, is thicker than the mean material thickness of the other bendable segments, corresponding to the larger bending moments which occur at the first-mentioned bendable segments. Thus the same degree of expansion or compression occurs in all the bendable segments and in the strain gauge elements associated with said bendable segments.

Abstract: A transducer employs two separate pressure input ports. Each port is associated with a separate metal diaphragm behind which diaphragm is secured a transducer structure having a cup-shaped silicon pressure diaphragm which is retained within a hollow of the transducer which is oil filled. One transducer structure is a half bridge array and monitors the main pressure applied to the positive port. A full bridge is formed by two resistors associated with the positive port and two resistors in an array associated with the other port which is the negative port. The resistors in the array at the negative port are selected to be larger in magnitude than those at the positive port and exhibit a greater sensitivity per unit of applied pressure.

Abstract: A square diaphragm formed of monocrystalline silicon and integrally attached to a silicon frame surrounding the diaphragm at its four edges. A serpentine resistor is diffused into the surface of the diaphragm adjacent each of the edges and the resistors are connected in a Wheatstone bridge configuration. The frame of the diaphragm is anodically bonded to a pyrex base member so that all four edges of the diaphragm are fixed relative to the base member and each other. The volume between the base member and the diaphragm is vented to prevent any differential pressure from occurring on the diaphragm.

Abstract: A strain sensitive element for use in a system for converting mechanical movement of portions of the element which are movable relative to each other into electrical signals, includes a planar substrate including an N-type silicon material wherein the substrate includes grooves extending into the substrate defining an integral hinge portion between at least two relatively movable parts. At least one strain gage extends across a groove without any separate support so that the strain gage and the hinge portion are spaced apart. The strain gage is joined to two of the relatively movable parts of the substrate. At least one elongate frangible link extends across a concave pit in the substrate. The frangible link is derived from the same silicon material as the substrate. The midportion of the frangible link is spaced from the lower surface of the pit and the end portions of the frangible link are joined to the substrate. At least one resistor is provided.

Abstract: A semiconductor pressure sensor wherein a semiconductor chip of diaphragm type is supported by a mount plate through a thin tubular supporting member or a pressure inlet tube having a coefficient of thermal expansion similar to that of a substrate constituting the semiconductor chip. The semiconductor chip is fixed to the thin tubular supporting member or the pressure inlet tube by means of a bonding material, and the thin tubular supporting member or the pressure inlet tube is fixed by means of a bonding material having a high bonding strength with respect thereto, thus absorbing thermal stress produced due to the difference in coefficient of thermal expansion.

Abstract: A force sensitive structural element comprising an extrusion of high strength aluminum alloy to which strain gages are attached and a base plate constructed of dissimilar material mounted in a housing. The height and coefficient of thermal expansion of the extruded member are selected relative to each of the height of the housing and coefficient of thermal expansion of the housing and the area of a resilient seal between the housing and a load carrying member attached to the extrusion. Variable magnitudes of expansion of the materials tends to collectively cancel the variation in barametric effects of thermal changes acting on the load cell.

Abstract: A strain gauge includes a flexible substrate and film of microfine grains of amorphous silicon connected between electrodes. A strain gauge assembly comprises a substrate, a first electrode formed on the substrate, a semiconductor body connected at a first end to the first wire and including a plurality of layers of different semiconductor materials forming a blocking diode and a resistance, and a second electrode connected to a second end of the semiconductor body such that the diode and resistance are between the first and second electrodes.

Abstract: A transducer responsive to rotational movement comprises a support member on which a shaft is rotatably mounted. Relative movement between the member and the shaft is sensed by flexure of a strip of a piezo-resistive mateial. Typically, the strip is facribed from signle crystal silicon.

Abstract: Semiconductor strain measuring apparatus for producing electrical output signals indicative of physical strains, in which a single crystal silicon substrate has the impurity concentration within the range between 1.times.10.sup.16 cm.sup.-3 and 2.times.10.sup.19 cm.sup.-3, thereby inhibiting the increase in the reverse leakage current flowing from the strain gauge through the substrate at high temperatures and thus enabling exact measurements even at high temperatures above 180.degree. C.

Abstract: A piezoresisitve pressure sensor having a diaphragm of silicon nitride with a stressed resistor under the edge of the diaphragm in a single crystal supporting wafer. The signal is derived from the stress in the silicon where the diaphragm attaches to the edge of the opening etched through the silicon.

Abstract: A constant bending moment device (70) for strain gauge measurement of a force (F) upon an object (32) by means of bending moment. Device (70) is provided with a base member (30) that is adapted to engage object (32) and has a pair of spaced-apart column members (34, 36) extending away from the side of base member (30) facing away from object (32). Column members (34, 36) have respective substantially parallel neutral axis (38, 40) and respective moment arms (37, 39) that extend generally orthogonally towards each other in overhanging relationship to base member (30) and merge at a common portion (24) therebetween having a loading axis (46) that is substantially parallel to neutral axis (38, 40) and equidistant therebetween.

Abstract: An electrical strain gauge is provided in which the strain-responsive circuit element is formed from a thin film deposit on a surface of a metal substrate on which an insulating film has already been deposited. Connections are made directly to the circuit element by the ends of connecter leads that are bonded into insulating plugs in apertures in the substrate. The plugs and the insulating film are glasses to which the substrate and the circuit element are bonded. A further glass layer encapsulates the circuit element. As a result a very robust form of gauge is provided that can be used in high temperatures and in chemically active environments.

Abstract: A compression strain gauge transducer assembly (10) includes a sensing member (14) that receives a strain gauge transducer (16) within a counterbored hole (26) through a head (18) and shank (20) of the sensing member. An inner pilot end (28) of the sensing member hole receives a pilot (40) of the transducer with flat annular seats (30) and (40) of the hole and the transducer engaged in a manner that provides accurate readings of compression loads in association with the pilot construction. An intermediate portion (46) of the transducer (16) has outer surfaces (48) that define a square cross section with strain gauges (50) mounted on the outer surfaces axially inward from a threaded outer transducer portion (52) received by a threaded outer portion (34) of the sensing member hole (26).

Abstract: A load cell has four strain gauge resistors formed through an insulation layer on the beam body having a strain generating section, a conductive pattern for forming a bridge circuit by coupling the strain gauge resistors compensation resistance sections for compensating the bridge balance and span of the bridge circuit is provided. A section of the conductive pattern except the section coupled to the strain gauge resistors is disposed at a position sufficiently isolated from the strain gauge resistors.

Abstract: In a semiconductor pressure transducer in accordance with the present invention, an oxide film is formed on a semiconductor base having a strain gauge resistor element for the purpose of protecting the strain gauge resistor element. Over the oxide film, a conductive metal film is formed which does not overlap with the strain gauge resistor element through said oxide film.

Abstract: An electromechanical transducer is provided, and the process for making it, which utilizes a piezoresistive element or gage which is crystallinally the same as the base or substrate upon which it is supported. The gage of the invention is a force gage, and is derived from its substrate by etching in a series of steps which, ultimately, provide a gage with substantially reduced strain energy requirements, because the volume of the gage may be as small as 3.times.10.sup.10 cubic centimeters of stressed material. In its most preferred form, the element or gage is etched free of its substrate to provide, in effect, a "floating gage." This is achieved by defining the gage in its substrate or in material rigidly bonded to its substrate, etching away immediately adjacent material, and leaving the gage free in space, while supported at each end on the substrate.

Abstract: An isotropic strain sensor having four mounting points interconnected by four legs, two of which are bowed toward each other and two of which are bowed away from each other. A strain sensing element mounted on at least one of the legs provides an electrical indication of the deflection of the leg. As a result, the strain sensor measures isotropic strains in an object to which the strain sensor is attached through the mounting points. Another embodiment of the strain sensor utilizes three mounting points interconnected by legs, two of which are bowed outwardly and one of which is bowed inwardly. Both embodiments of the strain sensor produce outputs that are a nonlinear function of the sensed isotropic strain. This nonlinear characteristic allows the strain sensor to provide an output that is a linear function of the load applied between the center and outer periphery of a freely supported disc that has a strain that is a nonlinear function of the applied load.

Abstract: The load cell, in particular for weighing systems, consists of a compressively loaded member which is provided with strain gauges. In order to prevent measurement errors caused by elevated temperatures or other environmental influences on the connection between said strain gauges and said member, the strain gauges are deposited on a separate support by means of thin-film techniques, and the support is welded to the center of the member.

Abstract: An integrated sensor for force and motion, includes a solid insulating material body, a flexible metal strip for force transmission sealed to and extending out of the body, a piezoresistive probe in the form of a silicon wafer fastened on the metal strip in the body for mechanical loading by the metal strip, conductive connections sealed to and extending out of the body for application to an electrical instrument and for voltage supply to the probe, and at least two electrical terminals connected between the silicon wafer and the conductive connections.

Abstract: A load detector which includes a pin-like member arranged between force-transmitting members, a hole formed in the pin-like member along its neutral axis for bending deformations thereof, an insertion member inserted in the hole and having at both end parts thereof securement portions and at a central part thereof one or more deformation-sensing portions which are provided with their axis of symmetry coincident with the neutral axis of the pin-like member, are responsive to each load applied to the pin-like member, undergo deformations and hence enlarge the resulting strain, and a mechanism for converting the extent of deformation of the deformation-sensing portions into signals so as to obtain only portion of the resulting strain which portion has been produced by each shear deformation of the pin-like member. Owing to the position of the hole, the pin-like member has sufficient strength and rigidity and can thus be used as a connecting pin or bolt.

Abstract: A strain gauge transducer (10) disclosed has particular utility when utilized with a bolt (12) to sense loading and has a construction which permits accurate axial alignment, testing before installation, removal for inspection and any necessary repair, and accurate readings that are not substantially affected by bending loading. The transducer (10) includes a body (30) having a web (40) extending between a threaded inner end (32) and an enlarged outer head (34). An annular seat (36) on the head (34) engages a bolt hole surface as the threaded inner end (32) is received by a threaded portion of the bolt hole. At least two strain gauges (46) are utilized with each mounted on one of the parallel web surfaces (42), and wires (50) connected to the strain gauges extend through a wire passage (48) in the enlarged head to permit a signal to be sensed by the strain gauges and fed to suitable instrumentation. In the preferred construction, the web (40) has a thickness in the range of about 0.020 to 0.

Abstract: The deforming body of a force measuring device or load cell is provided with radial stems (3) equipped with foil strain gages (7) and integrally connected to a hollow cylindrical outer ring (1) and to a central hub (2). The outer ring (1) and the central hub (2) extend axially on both sides of a central plane (5) at least as far as three times the largest thickness of the radial stems (3). A force introducing flange (13) is arranged on the outside of the outer ring (1) and lies in the radial central plane (5) of the radial stems (3). Each stem (3) is thicker at its ends near the hub and ring so that the thinnest stem portion is located approximately intermediate the stem ends for providing a linear characteristic for the load cell which is substantially non-sensitive to any loads other than loads applied perpendicularly to the central radial plane.

Abstract: A beam assembly for a force transducer of the type which includes a tapered beam portion having one or more strain gauges attached thereto. The beam assembly is in the form of a one-piece cylindrical member having an L-shaped slot formed therethrough to define a beam portion to which said strain gauge is attached, and a lever portion. A first force transmitting strut is attached to the beam portion and a second force transmitting strut is attached to the lever portion.

Abstract: A load cell, of the type that converts the magnitude of an applied load into an electrical signal, has a circuit board designed to facilitate wiring. The load cell includes a load cell body, strain gauges attached to the load cell body, and the circuit board which also is attached to the load cell body. The circuit board is composed of a flexible board, a wiring pattern formed on the flexible board, and soldering portions provided on the wiring pattern on either side of a bending portion at which the flexible board is bent for attachment to the load cell body. Symbol marks for identifying terminals are provided adjacent prescribed terminals of the wiring pattern formed on the circuit board.

Abstract: A transducer structure is disclosed which comprises a single crystal semiconductor diaphragm dielectrically isolated by a layer of silicon dioxide from a single crystal gage configuration. The methods depicted employ high dose oxygen which is ion implanted into a monocrystalline wafer to form a buried layer of silicon dioxide with the top surface of the wafer being monocrystalline silicon. An additional layer of silicon is epitaxially grown on the top surface of the wafer to enable the etching or formation of a desired gage pattern.

Abstract: A strain gauge or transducer is provided incorporating a supported film electrical resistance element whose electrical resistance varies as a function of applied mechanical strain and is provided with electrically conductive terminals. The resistance element comprises a dispersion of electrically conductive or resistive particles in an organic polymer together with an optional electrically insulating filler material. In a particular embodiment, the resistance element is supported on a member of anodized aluminum.

Abstract: A dynamometer is provided with a testing member having a bending beam. The bending beam has an end embedded in a support and is elastically deformable in bending under the influence of a force Q applied to its opposite end. The dynamometer further comprises a sensor for detecting the deformation of the beam. Anchorage zones are defined in the material of the beam, for receiving four rows of windings of prestressed gauge wire having their principal strands directed approximately perpendicularly to the force Q. The principal strands remain in close contact with the beam in the bending zone. Two of the rows of windings have their principal strands arranged along the tensioned fibres of the beam and the other two have their main strands arranged along the compressed fibres of the beam. The four rows of windings form an electrical bridge assembly.

Abstract: The measuring element for a dynamometer consists of a band-shaped substrate of amorphous metal. The band-shaped substrate has one or two necked-down sections on which strain gauge resistors are arranged in the direction of load application. The resistor or resistors may be connected in a bridge circuit together with reference resistors. The load-dependent elongation of the resistors unbalances the bridge circuit to create the desired output measuring signal. Use of a suitable alloy of amorphous metal results in good mechanical characteristic of the measuring element. Specifically, there is a high resistance to creep and to hysteresis effects, while relatively high loads may be measured. Further, such a measuring element is also immune to temperature variations.

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: A transducer structure is disclosed which comprises a single crystal semiconductor diaphragm dielectrically isolated by a layer of silicon dioxide from a single crystal gage configuration. The methods depicted employ high dose oxygen which is ion implanted into a monocrystalline wafer to form a buried layer of silicon dioxide with the top surface of the wafer being monocrystalline silicon. An additional layer of silicon is epitaxially grown on the top of the wafer to enable the etching or formation of a desired gage pattern.

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: A strain gage load cell having a body of material formed with a reduced section which is subjected to shear stresses when a load is applied to the body in a manner to deform the reduced section, a strain gage receiving opening formed in the reduced section so that deformation of the latter will deform at least part of the opening and cause it to assume an ovular configuration and at least one strain gage secured to the wall of the deformable portion of the opening and preferably aligned with one of the axes of the deformed portion of the opening.

Abstract: A force transducer for producing an output signal in proportion to the magnitude of an input force wherein an equal and opposite force is produced by a flexure assembly comprised of a compound leaf-spring flexure having opposed outer sections, anchored in and cantilevered from a fixed and a movable base respectively, which gradually decrease in cross-sectional area to a thin middle section wherein the movable base is constrained to linear displacement from a null or neutral position by having the force applied along a line normal to and passing through the center of the thin middle section and transmitted to the movable base through a rigid connection. A modified form of flexure assembly is disclosed comprised of parallel compound flexures each having a thin middle section and opposed outer sections which are anchored in and cantilevered from a fixed common base and a movable common base.

Abstract: An electromechanical bending force receiver for weighing cells and the like in which at least one strain gauge is disposed in a notch-like recess in a bar-shaped bending body with a step surrounding the recess to form a plane surface located in the zone of the body which is neutral to bending and with a covering foil located in said zone hermetically bonded to said surface.

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: 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: The invention relates to a measuring device using a strain gauge.The device comprises a test body (1), whereof one face (6) is compressively stressed and to which is fixed a strain gauge (7) constituted by a resistive coating (8) deposited on a thin glass support (9), the thickness of the latter being approximately 150 .mu.m.Application to electronic weighing.

Abstract: There is disclosed a semiconductor pressure transducer which employs a piezoresistive array fabricated on the surface of a thin substrate member and having the piezoresistors coupled to metallic contacts via ion implanted terminal leads.

Abstract: A shear beam load cell system (10) for measuring loads applied to a longitudinally extended beam member (12) having a central axis (24) extending in a longitudinal direction (22). Flexure isolation means (26) are formed on opposing longitudinal end sections (28, 30) of the beam member for minimizing strain on a central section (32) of the beam member (12) responsive to load displacements on the beam member (12). A multiplicity of strain gauge members (14, 16, 18, 20) are secured to the central section (32) of the beam member (12). Web flexure means (58) are formed within the central section (32) of the beam member (12) for mounting the strain gauge members (14, 16, 18, 20) to the beam member (12). The shear beam load cell system (10) minimizes stress changes in the central section (32) of the beam member (12) in response to non-measurement loads applied to the beam member (12).

Abstract: A semiconductor substrate has a major surface, another major surface on the opposite side of the first major surface, a strain gauge stripe formed in the central portion of the second major surface by diffusing an impurity therein, and electrodes connected to the strain gauge stripes. These strain gauge stripes are spaced from the peripheral edge of the second major surface by a distance greater than 1/3 of the length of the same major surface. The first major surface of the semiconductor substrate is bonded to an elastic metal load plate.

Abstract: A load-measuring device, comprising a ring to be interposed between two opposed bodies coaxial with the load axis. Circumferentially-spaced projections separate one axial face of the ring from one of the bodies, and similar but angularly-staggered projections separate the other axial face from the other body, so that when the bodies approach under load the ring is distorted to an undulating shape. The distortion may be measured by a set of strain gauges fixed to the axial faces of the ring, and the output of a second set of gauges fixed to the radial faces of the ring may serve to compensate for distortions of the ring caused by things other than axial thrust, e.g. temperature variation. The projections may be fixed to the ring, or fixed to and located by the ring casing so that they bear against the ring in use.

Abstract: A double shear beam strain gage load cell having an essentially U-shaped structure with a movable element disposed therebetween, the movable element being coupled to the legs of the U-shaped structure by a pair of shear beams carrying strain gages. The load cell may also include overload protective means to prevent damage to the shear beams.

Abstract: A measuring shaft intended to be fixed in a hole is equipped with strain gauges or similar devices for sensing a load. The inner end of the measuring shaft is threaded to engage with threads provided in the bottom of the hole, and the outer end of the measuring shaft is fixed in relation to the hole so that the measuring shaft like a part unseparated from the walls of the hole but nevertheless detachable, accompanies the motions of the said walls.

Abstract: A pressure transducer employs a semiconductor diaphragm with a top surface having located thereon a central boss area of a trapezoidal cross section surrounded or "framed" by a continuous groove of a predetermined width. Piezoresistive sensors are formed on the bottom surface of said diaphragm with a first sensor adjacent the outer edge of said groove and another sensor parallel to said first sensor and adjacent the inner edge of said groove, said groove operative as a stress concentrating area to enable said sensors to provide a relatively large linear output upon application of a force to said diaphragm.

Abstract: A load-measuring device, comprising a ring to be interposed between two opposed bodies coaxial with the load axis. Circumferentially-spaced projections separate one axial face of the ring from one of the bodies, and similar but angularly-staggered projections separate the other axial face from the other body, so that when the bodies approach under load the ring is distorted to an undulating shape. The distortion may be measured by a set of strain gauges fixed to the axial faces of the ring, and the output of a second set of gauges fixed to the radial faces of the ring may serve to compensate for distortions of the ring caused by things other than axial thrust, e.g. temperature variation. The projections may be fixed to the ring, or fixed to and located by the ring casing so that they bear against the ring in use.