Abstract: Pressure sensitive direction devices are provided which may facilitate assembly and provide higher tolerance for variation in alignment of components while still providing for pressure sensitive direction detection. The devices of the present invention may be particularly advantageous when integrated into devices, such as cellular radiotelephones, to provide a user interface to facilitate user navigation through increasingly complex menu structures. In various embodiments, the present invention may detect pressure in addition to two and, preferably, at least four directions. In particular embodiments, the devices of the present invention provides a switching device having a plurality of trace grid areas located, for example, on a printed circuit board and actuated responsive to pressure applied by a user through a poly-dome layer where increase pressure results in contact with a greater number of the traces in respective grids.

Abstract: Disclosed is an electronic pressure-sensitive device which has a long service life and which is capable of detecting with high accuracy loads of various magnitudes including values in proximity to zero. In the electronic pressure-sensitive device, first and second resistive element layers 2b and 6b are formed on the outermost surfaces of first and second contact portions 2 and 6, and the first and second resistive element layers 2b and 6b are constantly maintained in an electrical contact state, the force bringing the first and second resistive element layers 2b and 6b into press contact with each other being detected as the electrical resistance between the first and second contact portions 2 and 6.

Abstract: A linear position sensor for sensing the position of an attached object. The linear position sensor uses a strain gage to detect the position of the object. The sensor includes a housing and a ramp shaped actuator located in the housing. The actuator is attachable to the object. A strain gage is positioned in contact with the actuator. The actuator applies a strain to the strain gage as the actuator is moved. The strain gage generates an electrical signal that is proportional to the position of the object.

Abstract: A rotary position sensor for sensing the position of an attached rotating object. The rotary position sensor uses a strain gage to detect the position of the object. The sensor includes a housing and a rotor located in the housing. The rotor is attachable to the object. A strain gage is positioned in the housing adjacent the rotor. The rotor rotates so as to contact the strain gage and apply a strain to the strain gage. The strain gage generates an electrical signal that is proportional to the position of the object.

Abstract: A method of using an analog sensor variably depressed by only a single human finger to variably control an electronic game, the method including the steps: a) depressing, with the human finger, the analog sensor with varying pressure for variably controlling the electronic game; and b) receiving, through the finger, a user discernible snap-through tactile feedback. Additionally, a second depressing may be applied substantially because of the receiving of the feedback.

Abstract: A rotary position sensor for sensing the position of an attached rotating object. The rotary position sensor has a housing and a volute shaped rotor having a variable width that varies about the circumference of the rotor. The rotor is positioned within the housing and is attached to the object. The rotor rotates as the object rotates. A strain gage is positioned in the housing. The rotor contacts the strain gage and applies strain thereto such the strain gage deflects according to the variable width of the rotor. The strain gage generates a variable electrical signal that is proportional to the rotational position of the object.

Abstract: A current limiter device comprises at least two electrodes; an interlocked-array electrically conductive composite material disposed between the electrodes; interfaces disposed between the electrodes; an inhomogeneous distribution of resistance at the interfaces whereby, during a high current event, adiabatic resistive heating at the interfaces causes rapid thermal expansion and vaporization and physical separation at the interfaces; and means for exerting compressive pressure on the electrically conducting composite material. The interlocked-array electrically conductive composite material comprises an interlocked-array of spaced apart discrete regions of at least one insulating flexible material and at least one electrically conductive composite material. A method for forming the interlocked-array electrically conductive composite material structure is also set forth by the invention.

Abstract: A control device is provided for an industrial truck, in particular the towbar of a towbar-guided industrial truck, having a circuit element to generate a multi-stage electrical control signal. The invention teaches that the switching element has at least one contact membrane (6) which can be electrically connected by a pressure force exerted on the contact membrane (6) with at least one of a plurality of contact points (2) that correspond to the contact membrane (6). The contact points (2) are connected by electrical resistors (R1-8). The electrical resistors (R1-8) are preferably connected in series, whereby the connecting line between each two resistors is connected to a contact point (2). There are two sliders (8a, b), each of which exerts a pressure force on the contact membrane (6), as a result of which a contact point (2) can be connected to a contact area (3).

Abstract: The conventional variable resistor has a problem in that, because a pressure-sensitive member made of a pressure-sensitive conductive rubber is used, a serious scattering is caused in the characteristic (change curve), and scattering of thickness in the manufacture of the pressure-sensitive member results in a large scatter of the characteristic (change curve). The variable resistor of the invention uses the first resistor pattern forming the variable resistor. It is therefore possible to provide a variable resistor which scattering in the manufacture is smaller, can achieve a uniform resistance change characteristic, and gives a high accuracy.

Abstract: The invention concerns a force sensor (10) comprising a first electrode (22) and a second electrode (24) made of conductive material, which are arranged spaced from each other on a first insulating support (12). The invention is characterised in that a contact element (26) is conductive material is placed opposite the two electrodes and some distance therefrom, said contact element t(26) being pressed against said electrodes (22, 24) when a force is exerted on the pressure sensor (10) and at least one of the electrodes (22, 24) is coated with a pressure sensitive material layer (28, 30).

Abstract: A deflection sensing system for detecting deflection includes one or more deflection sensors between opposing sets of extensions. When one set of extensions is moved toward an opposing set of extensions, the deflection sensors are deflected. A preferred deflection sensor is a flexible potentiometer, which has a resistance that changes as the flexible potentiometer is deflected A flexible potentiometer includes a variable resistance material on a substrate. In a preferred system, the flexible potentiometer includes a cantilevered section, which is deflected about an extension with respect to the remainder of the flexible potentiometer, or with respect to a portion of the substrate not including the variable resistance material. A flexible potentiometer experiences less stress when in cantilevered form than when stretched between two extensions. In either case, the extensions may be joined to first and second corrugated plates.

Abstract: A low cost analog deflection sensor assembled from a single component part which lends itself for use as a joystick. A central contact is surrounded by peripheral contacts and aligned by a dielectric spacer. Application of deflectional force results in one or more signals of measurable resistance which can be translated into speed and directional vectors.

Abstract: A current limiting device utilizes an electrically conductive composite material and an inhomogeneous distribution of resistance structure. The electrically conductive composite material comprises an organic binder portion comprising a high Tg epoxy and a low viscosity polyglycol epoxy; at least one epoxy curing agent; and a conductive powder.

Abstract: Pressure sensitive layers are disposed on respective resin films through electrodes to face each other, and include high conductivity flaky carbon particles and low conductivity amorphous-based carbon particles. The two kinds of carbon particles are bound together by a resin-system binder. Accordingly, when a pushing force is applied to the resin films, an average distance between the carbon particles is decreased to cause a tunnel conduction phenomenon, resulting in a decrease in conductive resistance between the electrodes. As a result, a pressure sensing property can be made gentle.

Abstract: A pressure activated switching device includes an electrically insulative standoff positioned between two conductive layers. The standoff is preferably a polymeric or rubber foam configured in the form of contoured shapes having interdigitated lateral projections. Optionally, the switching device can include a piezoresistive material positioned between a conductive layer and the standoff. The pressure activated switching device can be used, for example, in a safety sensing edge system for a movable door.

Abstract: A curved disc joystick or pad with improved performance, reliability and durability can be used as a cursor pointing device for computers, remote controls, video games, consumer electronics, industrial controllers, automotive and other applications. A conductive spring or sheath connects to a conductive curved rubber transducer which can be deflected to make contact with conductors on a printed circuit board, providing electrical outputs to a microprocessor or other device. A ribbed locking extension may be added to automate the assembly process. In addition, a collar may be provided to produce a controllable product, both in terms of manufacturing and performance.

Abstract: An electrical switch has spaced, facing coupler and carrier layers with a set of electrodes formed on the facing surfaces thereof. There is an aperture in the coupler layer. A conductive armature is disposed in the space between the coupler and carrier, aligned with the aperture. The coupler is a magnet and the armature is made of magnetic material so the armature is normally held in engagement with the coupler. A user can press on any part of the armature through the aperture to cause a first portion of the armature to break away from the armature and contact the electrodes on the carrier while a second portion of the armature remains in contact with the coupler. The electrodes are arranged to provide an output which is dependent upon the location of contact with the armature.

Abstract: A compact, low-cost pad pointing device with improved performance, reliability and durability, having an integrated selection switch, that can be used as a cursor pointing device and selection mechanism for computers, remote controls, web TV, TV guide browsers, video games, consumer electronics, industrial controllers, medical, automotive and other applications. A contact surface can be deflected to positions on an electrical medium that results in the generation of speed and direction signals while a selection switch may be simultaneously activated through the same control element.

Abstract: A motion transducer having a user moveable plunger which compresses a spring for generating a force proportional to plunger displacement and applying the generated force to an actuator telescoped onto the plunger. The actuator has an elastomeric pad on the surface which contacts and reacts the generated force onto a force/pressure sensitive resistive strip which varies its resistance with the changing force applied by the elastomeric pad. The changes in resistance may be electrically detected to give an indication of plunger travel.

Abstract: A sensor having a housing; two highly conductive elements fixed in-part within the housing and in-part exposed external of the housing; the conductive elements separated from one another within the housing in a normally open arrangement. A resilient dome-cap is positioned within the housing, and in some embodiments is conductive and in constant contact with one of the conductive elements, and in other embodiments the dome-cap need not be conductive. A depressible actuator is movably retained by the housing with a portion thereof external of the housing to be accessible for depressive force to be applied thereto by a mechanical device or human finger/thumb. The actuator also includes a portion positioned to allow depressive force applied thereto to be applied to the dome-cap. Pressure-sensitive variable-conductance material is contained within the housing and electrically positioned as a variably conductive element in a current flow path between the two conductive elements.

Abstract: A membrane potentiometer that uses magnets to keep the membranes separated. A controller has a backplate and a cover that has sidewalls and a top wall which has a central opening defining a cavity. The cover mounts to the backplate. A pair of membrane potentiometer are interposed between the cover and the backplate to receive a first voltage, and output a second voltage that is a percentage of the first voltage. A pair of magnet assemblies are located on outer surfaces of the membrane potentiometer to generate a magnetic repulsion force to keep the membrane potentiometer separated from each other.

Abstract: A thick-film strain-sensing structure for a media-compatible, high-pressure sensor. The strain-sensing structure generally includes a metal diaphragm, at least one electrical-insulating layer on the diaphragm, an interface layer on the electrical-insulating layer, and at least one thick-film piezoresistor on the interface layer for sensing deflection of the diaphragm. The interface layer and the electrical-insulating layers are preferably formed by thick-film processing, as done for the piezoresistors. For compatibility with the metal diaphragm, the electrical-insulating layer has a CTE near that of the diaphragm. The interface layer is formulated to inhibit and control diffusion of the electrical-insulating layers into the piezoresistors. For this purpose, the interface layer is formed from a composition that contains, in addition to a suitable organic media, alumina, zinc oxide, and at least one glass frit mixture comprising lead oxide, a source of boron oxide such as boric acid, silica and alumina.

Abstract: A force transducer includes an elongated lever arm attached to a substrate having a central portion and substantially planar tab regions that project outwardly from the central portion along first and second orthogonal force-detecting axes. The substrate undergoes localized strain approximately at the junctions of the tab regions and the central portion when an external force is applied to the free end of the lever arm. A thick film strain gauge material is screen printed directly onto the substrate in at least a first location and a second location and conductive pads on the substrate are electrically coupled to the thick film strain gauge material at each location to define a first strain gauge oriented along the first force detecting axis and a second strain gauge oriented along the second force detecting axis. The lever arm can be of a compliant construction to provide proprioreceptive feedback to a user.

Abstract: A variable resistance transducer responsive to an applied pressure including a smooth resistive layer on a flexible substrate and deposited thereon by printing or imaging technology, small points of nonconductive or semiconductive material, and resistive interdigitating fingers where in one finger is a wiper so that position on the resistive layer can be sensed.

Abstract: A pressure sensitive sparkless switching device includes a layer of piezoresistive cellular polymer foam, at least two conductive layers, and an insulative spacer element having at least one opening. When pressure is applied to the device the piezoresistive foam disposes itself through the opening of the spacer element and makes electrical contact between the conductive layers. The resistance of the piezoresistive foam varies with the amount of pressure applied to provide an analog as well as on-off function. The device may also provide multiple switching, and shear detection capabilities.

Abstract: Disclosed is the method of producing a piezo-device utilizing an ultra-thin Mo-C film as a piezoresistive material for a general class of improved piezo-device with the high sensitivity and the weak temperature dependence.

Abstract: A floating pin joint is provided for coupling a linear potentiometer to a machine for measuring relative movement between first and second component parts of the machine. The potentiometer has an elongated housing securable to the first component part and a drive actuator slidably attached to the housing. In one embodiment, the floating pin joint includes a bushing, an actuator rod and a spring. The bushing can be positioned in a mounting hole on the drive actuator with an annular bearing surface disposed at one end of the bushing facing outwardly from the mounting hole. The actuator rod has a flange disposed between a first end and second end which contacts the bearing surface when the second end of the rod is extended through the bushing. The spring attaches to the second end of the rod for maintaining the flange in contact with the bearing surface.

Abstract: A variable high-current resistor, especially for use as a protective element in power switching technology has already been proposed, which contains carbon as a resistance material, at least one boundary layer with a transition zone to another electric conductor being provided. By applying a contact pressure, the resistance in the transition zone can be kept low. Under the prior art, the resistance is converted into a highly resistive state by means of Joulean heat. In accordance with the invention, the contact pressure of the variable high-current resistor is able to be selectively influenced, the carbon- and/or carbon-black-containing layer being pressed by the surface pressure with a preset first value against the other conductor to adjust the low-resistance state of the resistor, and that, in the event of a short-circuit, this contact pressure being able to be reduced in a short enough time to a second value, at which the resistance in the transition zone goes up by at least two orders of magnitude.

Abstract: This invention provides apparatus and a method which self-adjust the pressure response of a digitizer pointing device or other device incorporating a pressure transducer according to the characteristics of the particular device and/or particular user of the device. For example, a digitizer user when inputting with a stylus pointing device may use different writing styles in simulated paint brush and in simulated chalk, or, the user may use the stylus device entirely differently when using it in a game or in a graphic arts application, or different users may use the same stylus device differently for the same application. Certain pressure parameters of the device are not set on a fixed basis, which would provide for an average, typical or generic pressure range and resolution.

Abstract: An improved carbon-free force sensitive ink for a force sensor. The ink when deposited and dried can function at temperatures of up to 350.degree. F. and pressures of up to 10,000 psi. The preferred ink includes a thermoplastic polyimide binder, conductive particles, intrinsically semi-conductive particles, and dielectric particles, all of an average particle size of 1.0 micron or less. The preferred semi-conductive particles are molybdenum disulfide, ferric and ferrous oxide particles. The preferred conductive particles are conductive metal oxide compounds that deviate from stoichiometry based on an oxygen value of two, such as conductive tin oxide, Fe.sub.3 O.sub.4 iron oxide, and mixtures of them. The preferred dielectric particles are silica. The binder is present in an amount of 20 to 80% by volume. The sensor and a method of making the sensor are also disclosed.

Abstract: An adaptive keypad which has one or more keys includes, for each key, a pressure transducer positioned below a semi-rigid faceplate where the pressure transducer has a resistance which decreases as the pressure compressing the transducer increases. The transducer is connected in series with a capacitor to define an RC circuit for each key. Each RC circuit has a charge time proportional to the pressure applied to the key. A time capture circuit initially and thereafter intermittently, obtains the charge time for each RC circuit for each key and computes a conductance value from that time. The initial conductance value is stored in a memory. A comparing circuit intermittently compares the initial conductance value with each subsequent conductance value generated for a key. If the comparison value generated is greater than a predefined amount, a signal is generated indicating that a key has been depressed.

Abstract: A pressure sensor die is provided with a flexible membrane and a plunger which combine to amplify a low pressure signal while also providing media isolation between a fluid being measured and the internal components of a pressure sensor. One embodiment of the pressure sensor disposes an end of the plunger in direct contact with a pressure sensor die while another embodiment disposes an elastomeric diaphragm between the plunger and the pressure sensor die. This second embodiment creates a chamber between the plunger and the pressure sensor die in which a fluid is captured by movement of the plunger. The captured fluid is decreased in volume by movement of the plunger and the resulting increase in pressure in transmitted to a pressure sensitive portion of a pressure sensor die. The device is particularly useful in conjunction with applications where media isolation is required between the fluid being measured and the components of the pressure sensor, such as kidney dialysis machines.

Abstract: A cursor control device includes a single key cursor control which utilizes pressure sensitive resistors for controlling cursor movement. Pressure sensitive resistors are arrayed so as to provide an output corresponding to the magnitude and direction of an applied input pressure. Input pressure is transmitted to these resistors by a means for actuating these devices. The means for actuating can include a single key which incorporates functionality of both up, down, left and right cursor control keys and pointing devices to produce horizontal, vertical, diagonal and curvilinear cursor movement. Cursor control device offers mechanically simple, low cost construction, and can be incorporated onto many keyboard constructions. Cursor control device can be positioned on keyboards in many locations as best suits individual applications. Cursor control device can also be incorporated into other devices which require cursor control such as electronic mice.

Abstract: A force sensor is provided which incorporates a pressure transducer disposed within a housing structure. A force transmitting means, such as a shaft slidable within an opening, is provided to communicate force from an external source to a diaphragm of a pressure sensor. An elastomeric conductor is disposed between electronic components on the diaphragm of a pressure sensor die and conductive leads that are used to communicate signals from the pressure sensor die to components external to the present invention. In certain preferred embodiments, the present invention provides a preselected quantity of resilient material between a first end of the slidable shaft and the diaphragm of the pressure sensor die. Other embodiments place the first end of the shaft in direct contact with the diaphragm.

Abstract: A hot water tank construction, an electrically operated heating element construction therefor and methods of making the same are provided, the electrically operated heating element construction comprising a heating element and an externally threaded fitting for threading into an internally threaded opening in a wall of the tank, the heating element comprising an outer metallic tubular sheath and an inner conductive heater wire insulated from the sheath, the fitting comprising polymeric material, the heating element construction comprising an electrical resistance electrically interconnected to the sheath and being adapted to electrically interconnect the sheath to the wall of the tank, the polymeric material comprising an electrically conductive polymeric material that also comprises the resistance of the heating element construction.

Abstract: A pressure transducer includes a base ply, a resistance ply disposed on the base ply and at least two spaced apart contacts juxtaposed in relation to the resistance ply whereby at least one of the contacts may be pressed against the surface of the resistance ply. The resistance ply is made by spraying or silk screening a mixture of resin resistive to electrical conduction and a conductive particulate and then curing the composition to form a thin resistance ply having a surface with a multiplicity of micro-protrusions formed by the conductive particulate. The ratio of conductive particulate to resin is such that the mean distance between microprotrusions is greater than about five time the size of the conductive particles. The particles are in the range of about 0.5 to 10 microns and the resin layer is about is 0.4 to 0.8 microns thick.

Abstract: A pressure transducer includes a base ply, a resistance ply disposed on the base ply and at least two spaced apart conductors juxtaposed in relation to the resistance ply whereby at least one of the conductors may be pressed against the resistance ply. The resistance ply is made by spraying or silk screening a mixture of a continuous matrix conductive resin and a stannous oxide particulate and then curing the composition to form a solid resistance ply having a surface with a multiplicity of micro-protrusions formed by the stannous oxide particulate.

Abstract: The computer input device includes an elastic actuator button of generally hemispheric shape. An applied force causing an indentation in a curved portion of the button is transmitted via the material of the button to cause a corresponding elastic bulging of a bottom, normally flat portion of the button and of a conductive film and resistive film which are attached thereto. During such bulging, a portion of the resistive film is urged into contact simultaneously with two or three oppositely disposed conductive traces. This action can cause a cursor to be moved in a direction corresponding to the direction of force of the push when the device is attached to the proper circuitry. The amount of pressure applied to and transmitted through the elastic material of the button determines the size of the area of contact between the resistive film and the pattern of conductive traces and, ultimately, the speed and/or distance of movement of the cursor in that direction.

Abstract: A pressure transducer for measuring high differential pressure media in a harsh environment where a diaphragm assembly is mounted to an intermediate support number which is mounted to a main support member where the high pressure media impinges on the diaphragm to create a force opposing that provided by the diaphragm support structure thereby loading the diaphragm in compression. The strain sensitive piezoresistive elements are protected and sealed from the low pressure media by a passivation layer and electrical signal leads are attached to bonding pads formed on the diaphragm assembly which are sealed to the intermediate support member by a sealing cap.

Abstract: A hot water tank construction, an electrically operated heating element construction therefor and methods of making the same are provided, the electrically operated heating element construction comprising a heating element and an externally threaded fitting for threading into an internally threaded opening in a wall of the tank, the heating element comprising an outer metallic tubular sheath and an inner conductive heater wire insulated from the sheath, the fitting comprising polymeric material, the heating element construction comprising an electric resistance electrically interconnected to the sheath and being adapted to electrically interconnect the sheath to the wall of the tank, the polymeric material comprising an electrically conductive polymeric material that also comprises the resistance of the heating element construction.

Abstract: Unfired ceramic tape is fired to a ceramic substrate during the laminar fabrication of a thick film force sensing element to provide the fabricated sensing element with a force sensing zone which is effective in response to the application of force thereto to induce strain in the fired ceramic tape. A conductor and thick film resistor system is printed and fired to the tape during the fabrication process to provide the fabricated sensing element with an electrically detectable signal correlating with the induced strain. Accelerometer and pressure sensor embodiments are disclosed. The invention is well-suited for the commercial mass-production of sensing elements, such as for automotive vehicle usage, because it can practiced through the use of automated production processes.

Abstract: A silicon pressure chip operates in a two-wire resistive mode. A thin-film resistor located on a long silicon beam which is the thicker portion of a thin diaphragm is partially shorted out by a metallized deflection stop. The pressure response of the resistor is determined by the resistor layout.

Abstract: A hot water tank construction, an electrically operated heating element construction therefor and methods of making the same are provided, the electrically operated heating element construction comprising a heating element and an externally threaded fitting for threading into an internally threaded opening in a wall of the tank, the heating element comprising an outer metallic tubular sheath and an inner conductive heater wire insulated from the sheath, the fitting comprising polymeric material, the heating element construction comprising an electrical resistance electrically interconnected to the sheath and being adapted to electrically interconnect the sheath to the wall of the tank, the polymeric material comprising an electrically conductive polymeric material that also comprises the resistance of the heating element construction.

Abstract: A shift assisting mechanism for assisting the shifting of a dog clutch of a marine transmission by reducing the engine speed. The requirement for engine speed reduction is sensed by a pressure sensitive conductive rubber type pressure sensing switch contained within the interconnection between the operator and the dog clutch.

Abstract: A tactile sensor for providing information as to the distribution and magnitude of tactile force applied to its surface, having a compression sensitive layer of conductive elastomeric cellular material in conjunction with an elastomeric cover layer and a base layer having one or more electrodes in conductive contact with the cellular material. The elastomeric cover layer has a conductive bottom surface in contact with the compression sensitive layer. The circuit path between the outer layers is such that the conductivity varies in response to deformation caused by tactile pressure applied thereto.

Abstract: A pressure responsive potentiometer, including an elastic body which includes a silicone mass mixed with a carbon fraction in a quantity such that the electrical resistance across the body is changed when a force is applied to the body, which body has electrically conductive contact tabs or plates or like elements connected thereto in mutually spaced relationship. The invention is characterized in that the body (1) is composed of a mixture including a silicone mass, silicone oil and carbon grains, where the weight ratio of silicone mass to silicone oil is about 1:0.3 to 1:0.5, preferably about 1:0.4, and where the carbon grains have a size which is greater than a size corresponding to a 50 mesh sieve (50 meshes per inch) and a size which is smaller than the smallest dimension of the body (1).

Abstract: A piezoresistive pressure transducer employing a sapphire force collector diaphragm having piezoresistive films of silicon epitaxially formed on a major surface thereof, preferably in a Wheatstone bridge pattern. The silicon piezoresistive film is preferably of a thickness of from 1,000 to 60,000 angstroms and is doped with boron in the range of from 5.times.10.sup.17 to 9.times.10.sup.20 atoms/cc. Electrical lead traces and electrical contact pads are also formed on the major surface of the force collector diaphragm. The diaphragm is mounted on a pressure cell base having a cavity in the upper surface thereof, the diaphragm enclosing the cavity so as to form a chamber with the piezoresistive silicon films within said chamber. The diaphragm is hermetically bonded by a ceramic glass to the base in a vacuum such that the chamber provides a vacuum pressure reference.

Abstract: The position sensor of the present invention includes a pair of elongated conducting members disposed in a parallel arrangement and a conducting metallic ball or mercury drop freely movable following the pair of elongated conducting members while maintaining a simultaneous contact with the pair of elongated conducting members, which combination provides two electric circuits respectively including a first circuit including a first poriton of the two elongated conducting members and the contact provided by the metallic ball or mercury drop, and a second electric circuit including the second portion of the two elongated conducting members and the same contact, wherein the metallic ball or mercury drop divides the combination of the two elongated conducting members into the first and second portions.

Abstract: A torsion transducer for providing electrical position and angular velocity signals for a device driven in a bidirectional partial rotational mode, such as commonly found in the rotary actuator arm of a disc drive for rotating computer memories. The torsion transducer comprises a torsion bar in the form of a wire, with one end attached to the rotating element of the actuator arm and the other to a piezoelectric transducer operating in the shear mode, which is anchored to the stationary frame of the device. As the torsion bar is twisted by the angular motion of the rotary element, torque is applied to the piezoelectric transducer, which then generates an electrical signal that can be processed to represent position and angular velocity of the rotary elements of the actuator arm.

Abstract: A force or pressure sensor includes a monocrystalline silicon diaphragm coated with silicon dioxide upon which single crystalline silicon resistors are fused in a low profile pattern on the surface. The resistors are almost perfectly electrically isolated from each other and from the underlying silicon substrate. The structure is fabricated by forming resistors in a first wafer and then affixing that surface of the first wafer to the silicon dioxide layer on the second wafer. All of the first wafer except for the resistors has been removed, and metal contact capable of resisting elevated temperatures are formed to provide electrical connections to the resistors.