Abstract: To measure pressure acting on a support (1), a sealed bag (2) which is filled with a fluid and has flexible bag walls (9, 10), and which is arranged on the support (1) and whose interior communicates with a flexible capillary tube (4, 4'), is used as a sensor. Connected to the free end of the flexible capillary tube (4, 4') is an evaluation device which detects pressure variation, it being possible for the end of the flexible capillary tube (4, 4') to be plugged into a block (5). The block has a bore (6) which continues the channel of the flexible capillary tube (4, 4') and is sealed at its end not: subjected to the flexible capillary tube (4, 4') by a diaphragm (7). The diaphragm bulges outwards in the event of a reduction in the volume of the bag (2). The extent of the outward bulging of the diaphragm (7) can be determined by an optical detector (15, 16).

Abstract: A device for monitoring force being applied by a wearer thereof to the wearer's foot, as during walking. The device is contained within a shoe-like structure which can be worn by a recuperating injured person or a person recovering from surgery, etc. The device includes a pressure sensitive element that produces an electrical signal that is related to the force, with this signal being used to alert the wearer when a force in excess of a preselected value occurs. Further, this signal can be used as input to data recording and analysis equipment. The signal transmission can be by direct wire connections, or via radio transmission. A vibratory motion is of particular value to alert the wearer of the point where the excess force occurs. The alerting device can be contained within the shoe, or in other apparatus utilized by a patient. Through the use of this device, a recovering patient will know how much weight to place on the leg in order to achieve maximum healing value.

Abstract: An apparatus for load and displacement sensing adapted for measuring normal and shear forces exerted on load bearing portions of a body. The apparatus includes a deformable pad and a plurality of sensors. Each sensor includes at least one magnet and at least one Hall-effect transducer affixed to opposite sides of the deformable pad. Normal forces are measured utilizing magnets having a planar North and South polarizations and the magnitude and direction of shear forces are measured utilizing magnets having alternating North and South pole segments disposed longitudinally therewithin. In another embodiment, normal and shear forces are measured utilizing a magnet having a point-magnetization. The force exerted on the body deforms the pad, bringing the magnet in close proximity to the transducer, which senses the change in the magnetic flux density.

Abstract: A self-contained system for measuring forces applied to the foot of a user includes a force sensor array positioned within the user's shoe between the foot and the inner sole of the shoe, the force sensor array including a multiplicity of individual force sensors arranged in a pattern that covers the entire area of contact between the sole of the user's foot and the inner sole of the shoe, an electronic circuit module removably attached to the side of the shoe, and a flat interconnecting cable for electrically coupling the force sensor array to the electronic circuit module.

Abstract: A foot-strike measuring system and method using a pair of tandem plates each having at least two sensors along the direction of travel for measuring force. By monitoring the signals on the sensors at the adjacent edges and comparing with those on the nonadjacent sensors, the system determines whether one foot is on both plates or one foot is on each plate. This allows collecting and tracking sensor signals for each foot separately. Center of pressure is also calculated using the speed of the treadmill.

Abstract: A force monitoring shoe (10) for monitoring the force being applied to a patient's leg, as during walking. The device is contained within a shoe-like enclosure which can be worn by a recuperating injured person. Provision is made, as with a spring, to absorb the shock of the step. When force equal to a selectable value has been applied, an alert system notifies the patient. With this device a recovering patient will know exactly how much weight to place on the leg during every step.

Abstract: An improved orthopedic weight monitor for detecting weight bearing forces on a lower extremity for orthopedic purposes, comprising in combination: flexible pad shaped for conforming to the bottom of a foot for placement inside of a shoe, cast or splint, the pad having a heel portion positionable beneath the heal of a user; sensor encased within the heel portion of the pad to be located beneath the heel of the user, the sensor comprising a thin, rigid rectangular plate having a foil strain gage coupled therebeneath; electronic module remotely positioned from the sensor to receive signals from the foil sensor; and electrical line extending to exterior of the flexible pad between the foil stain gage and the electronic module.

Abstract: An apparatus and method for monitoring pressure between the surface of a body part and a contact surface employ a plurality of pressure sensors disposed in a matrix array between the contact surface and the body part. The sensors produce analog force signals proportional to pressure, and a monitor receives the analog signals and produces output signals, preferably digital, having pressure data corresponding to the pressure at each sensor. A computer processor receives the output signals from the monitor to create a force profile for the sensor array. The sensors may be scanned as a read event in variety of manners, including periodic, continuous and triggered scanning. Where triggered scanning is desired, one or more switches act to initiate a read event. This monitoring apparatus and method is used, for example, to fit prosthetics, to monitor bed-ridden and wheelchair-bound patients, to reduce pain and sores caused by uneven distribution of pressure and to monitor pressure between a cast and a person.

Abstract: A footwear of the present invention is provided with tank chambers which are disposed to be in contact with an instep, sole and ankle of the user for applying pressure thereto to protect his foot from shocks. The tank chambers are filled with air and air pressure within the tank chambers can be adjusted. The footwear is further provided with a pressure sensor for measuring air pressure within the tank chambers to generate a pressure signal, and a pressure data displaying device for indicating pressure data on the basis of the pressure signal generated by the pressure sensor. Therefore, the user can make sure on the pressure data display device a pressure level at which the most suitable pressure for his foot is obtained. The user is also allowed to extremely easily adjust the air pressure at the above pressure level, watching an indication on the pressure data display device.

Abstract: Disclosed is an apparatus for selecting a mattress. The amounts of elastic deformation in a plurality of points of a measuring mattress having a predetermined hardness are electrically detected by pressure sensors. Based on the electric signals generated from the pressure sensors, a first average value in the amounts of deformation in the head portion and the leg portion of the user and a second average value in the amounts of deformation in the other portions of the user are calculated in a control device. First and second straight lines denoting these first and second average values, respectively, are displayed on a display device together with a mark designating the hardness of a mattress adapted to the user. The optimum hardness of the mattress is determined on the basis of the difference in the amount of deformation between the first and second straight lines, so as to enable the user to select a mattress of a hardness adapted to the user.

Abstract: An orthopedic exercise chamber such as a slipper including a light-weight, self-contained limb load monitor is disclosed. The limb load sensor circuit provides extended service life for the miniature power supply that is included in the slipper, thereby making the slipper suitable for out-patient use. A fluid-filled plantar chamber that supports the entire load borne by the patient's foot is connected to the sensor circuit, thereby providing improved monitoring of the load being carried by the leg or foot that must be protected from excessive loading.

Abstract: A detecting element for sensing surface pressure distributions comprising a substantially rigid insulating substrate, a plurality of scanning row electrodes, formed by metal deposition on said substrate, etched to form a pattern of substantially parallel electrodes which are spaced apart and oriented along a first axis, a thin resistive film, deposited on said substrate, having a resistance which varies as a function of contact area, a substantially resilient deformable surface layer, a plurality of scanning column electrodes, formed by metal deposition on said surface layer, etched to form a pattern of substantially parallel column electrodes which are spaced apart, said surface layer being bonded to said substrate by an anisotropic adhesive so that said column electrodes are oriented along a second axis which is perpendicular to said first axis, said surface layer transmitting pressure distribution to said row electrodes, resistive film, and column electrodes to form a matrix of variable contact resistances

Abstract: A force transducer which uses current pulses in a conductor to generate acoustic pulses in a magnetostrictive delay line. The pulses are sensed by a coil around the line. The magnitude of the pulses is modified by force applied to the transducer by changing the shielding effect of a magnetoelastic ribbon (between the conductor and the delay line) by applying a force to be sensed thereto. The transducers are economic and easily assembled into arrays for sensing stress distribution in two dimensions because the common conductors can be used for the columns of the array and common delay lines can be used for the array rows. Each column then has a common current-pulse generator and each row has a common detector coil. A similar technique may be used for sensing the spatial distribution of other parameters such as temperature, magnetic field or displacement.

Abstract: A force and pressure sensor is provided having two sets of parallel electrodes which are positioned facing one another and arranged so that electrodes of one set cross the electrodes of the second set at an angle to create a plurality of electrode intersections. Pressure-sensitive resistive material lies between the electrodes at each intersection. An adhesive layer is applied to at least one of the electrode sets in areas between electrode intersections to secure the first and second electrode sets in facing relationship, the adhesive layer preferably being applied in a pattern which provides passages where the adhesive layer does not exist to allow air to escape from interior areas of the electrode set. The thickness of the adhesive layer may be adjusted to permit preloading or to provide a threshold level for the sensor.

Abstract: A measuring platform having at least one force transducer rigidly fixed to either the base or cover element and to the other of the base or cover element movably to minimize measuring errors due to bending of the cover element under forces to be measured.

Abstract: A capacitive measuring pad is constructed of transverse conductive strips separated by a compressible insulator to form a matrix of pressure sensitive capacitive nodes. The nodes are repetitively scanned in sequence by a microcomputer to measure their respective capacitances, from which measurements a pressure map is then derived. The resulting pressure map may be displayed on a color graphics monitor with different colors representing diffrent pressures. Node capacitance is found by measuring the response of the mode to a driving signal of a known voltage. This measurement is accomplished by connecting one of the node's transverse conductive strips to the driving source and the node's other conductive strips to a sense amplifier. In order to isolate the node of interest from the influence of surrounding nodes, all of the conductive strips except the two intersecting the selected node are connected to ground.

Abstract: A distribution type tactile sensor, which comprises a plurality of electrodes provided in pairs at respective pressure sensing points on a pressure sensitive conductive rubber sheet capable of changing the electrical resistance responsive to compressive forces, and a rectifier element provided to respective electrodes for rectifying the current flowing across each pair of electrodes through the rubber sheet, the electrodes being divided into groups each comprising electrodes arranged in a line for respective polarities of the electrodes, electrodes in respective electrode groups being parallel connected to one another through electrode leads, and directions of the division of electrode groups divided for respective polarities being crossed with one another at respective pressure sensing points.

Abstract: The invention is concerned with an orthotic fitting device and method. An envelope and an adjacent diverticulum are connected to one another and are filled with a known amount of a viscous fluid. The diverticulum has indicia on it capable of indicating what portion of the fluid is within the diverticulum. The envelope is fitted against a portion of a patient's body which is to be cushioned and the fluid adjusts between the envelope and the diverticulum to provide proper cushioning for the foot. Flow communication is stopped between the diverticulum and the envelope and the amount of fluid in the diverticulum is determined from the indicia. An orthotic device in the shape of the envelope is then formulated containing the amount of fluid which remained in the envelope of the fitting device.

Abstract: A device is disclosed for measuring the areal distribution of compressive forces which act substantially vertically with respect to a deformable measuring surface. A matrix arrangement of force sensors is provided, each of which is formed as a capacitance at crossings of substantially perpendicular conductor paths. The conductor paths are fixed on the opposed surfaces of an elastically deformable area-type dielectric and adapted to be connected by conductive elements to evaluator electronics. The conductor paths are printed on plastic substrate films.

Abstract: A small, inexpensive, but reliable pressure warning system includes a plurality of pressure sensors which are disposed between an orthopedic restraining member and an injured portion of a patient's body, and a processor and alarm unit coupled to the pressure sensor and providing a warning when the pressure reaches a danger level (i.e. 30 mm) in which medical assistance is required. If the pressure goes above a critical value (i.e. 35 mm), another warning is provided that immediate medical attention is needed. The processor and alarm unit can be mounted directly on the patient's cast and are disposable, one-use items.

Abstract: A pressure distribution measuring system includes a pad of insulating material disposed between two linear arrays of electrodes to form a matrix of capacitive nodes. A capacitance related output signal that is obtained from a node of interest is used as a feedback signal and applied to other capacitors that are connected in common with the node of interest. The feedback signal inhibits the flow of current through these commonly connected capacitors, and thereby isolates the measured signal from any changes in the capacitance of these other capacitors. The pad includes a cental array of linear electrodes sandwiched between two layers of dielectric foam material. Two outer, aligned linear electrode arrays, oriented perpendicular to the central array, are respectively disposed on the outside surfaces of the dielectric layers. In a preferred form, alternating electrodes in each outer array are located on opposite sides of a support substrate.

Abstract: Systems including piezoelectric sensor elements advantageously mounted between supporting hard plastic material of various types or other mechanically similar materials. The sensor can further be supported by backup plate structures. Some backup plates show full shoe coverage and others show partial sole coverage. Detachable mounting formed by mechanically interengaging parts allow transducer inserts to be made in a modular manner for use in different sensor shoes or sensor insole pads, thus allowing many more patients to be analyzed and treated through use of the invention. Also disclosed is a digital charge signal integrator circuit.

Abstract: An instrument for measuring the pressure exerted upon a portion of the body of a bedridden individual lying on a mattress by that section of the mattress which is engaged by this body portion. A small flexible hollow member has a first air inlet and is adapted to be positioned for use between the body portion and the mattress section. A switch is disposed in the member with connecting leads extending out of the member. The switch is open when the air pressure in the member is at least equal to the exerted pressure and is closed when the air pressure in the member is less than the exerted pressure. A circuit including a lamp and an electric power source is connected to the switch to cause the lamp to be energized and lit when the switch is closed, the lamp being deenergized and dark when the switch is open. An air pressure meter has a second air inlet. A manually operated air pump is connected to both air inlets.

Abstract: An apparatus particularly suited for measuring the shape or contour of a surface under load, such as a mattress, is comprised of a humanoid having body limb extremities which are movable in a manner similar to the movement of comparable human extremities. Sensors are placed at joints, such as the knees and hips, to measure the amount of relative movement, i.e. deflection, that occurs at these joints when the humanoid is placed upon a mattress surface. The sensors provide an indication of the shape or contour of the mattress surface by correlation of the relative movement that occurs at these joints caused by the underlying mattress shape. In its preferred form, a movable frame is provided to raise and lower the humanoid in relation to the mattress surface to be tested. A "spine" is also advantageously provided with associated sensors to measure deflection, and thus surface contour, in the lower torso/abdominal region.

Abstract: The spaced beam and bearing arrangements each comprise a deflection beam and a support. The platform is disposed on and supported by the support for receiving and being deflected by an applied force. Thus, deflection of the platform is transmitted to the deflection beams to cause deflection of the deflection beams. The beam and bearing arrangements isolate beam deflections to two mutually perpendicular directions, which mutually perpendicular directions are both perpendicular to the longitudinal axis of each deflection beam. The deflection of the deflection beams is measured in the two directions thereof and the deflection beams are arranged such that no two redundant directions of the deflection beams are permissible.

Abstract: A multi-event notification system for monitoring preselected critical pressure points, as a function of pressure in a lapsed time, on the feet of persons being diagnosed as having diminished sensation in the feet. A plurality of pressure transducers for measuring and monitoring pressure at any number of points on a patient's foot are electrically connected to a microprocessor. The processor is programmable to integrate when pressure is sensed at the sensing points over a preselected time interval. If any of a number of the sensing points reaches a preselected threshold of pressure events over the given time interval, an alarm indicator connected to the processor provides an alarm indication that the total number of pressure events exceeds the threshold limit.

Abstract: A surface-area-pressure transducer comprises: at least one pair of electrode layers each including a plurality of electrically-conductive elements, the elements of one layer extending in spaced, crossing relationship to the elements of the other layer; and a compressively-deformable dielectric layer composed of fibers interposed between the two electrode layers to define therewith an array of capacitors whose capacitances are changed by the compression of said dielectric layer when subjected to pressure. Also described is a line-selector circuit for individually selecting each capacitor for measurement without electrical cross-talk from the other capacitors.

Abstract: An elongated elastically deformable housing is responsive to external force applied thereto and is connectable to a pressure evaluation device. A rigid tube longitudinally traverses the housing and defines therewith a closed annular space around the tube, which has a plurality of radial bores formed therein in an array extending the length of the housing and connecting the interior of the tube with the annular space, a hydraulic fluid being contained in the annular space and the tube. Means are provided at one end of the tube for the connection thereof to the pressure evaluation device.

Abstract: A pressure sensing device includes a sensor for continuously measuring the pressure on a patient's skin at the interface between the skin and a surface exerting pressure on the skin. A monitoring device monitors the pressure exerted on the skin and the elapsed time period during which the skin has been exposed to the measured pressure. An alarm then indicates when the combination of the pressure and the elapsed time is approaching a previously determined level in order to prevent damage to the patient's skin.

Abstract: Apparatus for evaluating a person's foot condition in terms of blood circulation in and anatomical shape of the feet has a transparent planar foot support with a thermographic film provided thereon to visually indicate the degree of blood circulation in the foot. The foot support is mounted on a stand with lamps for illuminating the underside of the foot support. Mirrors are positioned on the stand beneath the foot support to enable unobstructed viewing of the visual indication. By rotating the mirror, a camera may be used to photograph the visual indication of the person's foot condition. The apparatus provides an economic unit for use in readily evaluating a person's foot condition.

Abstract: The flexible force sensor having an electrical conductor releasably attachable to a test site and a plurality of relatively spaced electrical contacts supported for varying contact with the conductor such that when a force is applied to the force sensor, the electrical contacts and electrical conductor move into and out of varying areas and/or paths of electrical contact to produce electrical resistances therebetween corresponding to the extent of such areas and/or paths and as a function of the applied force.

Abstract: The flexible force sensor having an electrical conductor releasably attachable to a test site and a plurality of relatively spaced electrical contacts supported for varying contact with the conductor such that when a force is applied to the force sensor, the electrical contacts and electrical conductor move into and out of varying areas of electrical contact to produce electrical resistances therebetween corresponding to the extent of such contact and as a function of the applied force.

Abstract: A method is disclosed for using a tension gauge for comparing the tension required to move a frictional element relative to the nose of a wearer of a pair of eyeglasses when the frictional element is first disposed between and in frictional contact with a first nose pad of the eyeglasses and a first side of the wearer's nose to the tension required to subsequently move the frictional element relative the wearer's nose when the frictional element is disposed between and in frictional contact with a second nose pad of the eyeglasses and a second side of the wearer's nose. The gauge includes an elongated housing which defines a bore extending along the longitudinal length of the housing, a rod slidably cooperating with the bore and a first end of the rod disposed within the housing. A spring is disposed between the first end of the rod and the housing to bias the rod to a retractable position within the housing.

Abstract: This invention is a method and apparatus for practicing the method in which data may be uniquely recorded concerning the gait of a patient undergoing diagnosis and/or treatment in connection with podiatric matters. The method includes a special video recording and sound recording of the movement and effects of movement of the patient under consideration upon a treadmill under controlled conditions. The apparatus of the invention includes special mounting of video and sound recording apparatus in proximity to a visual observer and the patient with appropriate supporting framework adjustably controlling mounting and utilization of the treadmill in concert with the recording apparatus.

Abstract: Apparatus for analyzing the force acting on the human foot comprises television cameras for photographing the gait of the subject and for photographing the plantar surface of his foot through a transparent platform. The platform comprises a plurality of beams each of which is supported at each end by means for detecting the load imposed on each beam. The video outputs of the two cameras and the load on each beam are displayed on a monitor screen. The apparatus also includes circuitry for determining from the loads on the ends of the beam where the center of pressure is on each beam. These centers of pressure are displayed superimposed on the image of the plantar surface.

Abstract: The number of steps taken while walking are counted by straining a fatigue life gauge to change its electrical resistance each time the device is stepped on by a subject. The change in resistance of the fatigue life gauge is measured to ascertain the approximate number of steps taken.

Abstract: It is described a man locomotive functionality evaluating apparatus comprising a rigid platform adapted to support a subject walking thereonto and exercising on it a force and/or pressure due to said walking; a plurality of force and/or pressure transducing members operatively associated with the platform for providing electric signals representative of the force and/or pressure on the platform and a hybrid processor circuitally connected to said transducing members and adapted to in-line converting on output display means the time-space representation of the projection on a plane of the resultant of the forces and/or pressures acting on the platform.

Abstract: Footwear tester comprising a machine stand, a prime mover mechanism mounted on the machine stand, a footwear block supporting mechanism which supports freely a footwear block to be automatically advanced and retreated by said prime mover, a footwear block inclining mechanism which performs changes of the posture of said mechanism for supporting freely the footwear block, front operation mechanism and rear operation mechanism for controlling changes of the posture of said footwear block from the outside, and lift mechanism for bringing up and down a ground stand, wherein said respective mechanisms are interconnected with one another so as to control changes of the posture of the footwear block.

Abstract: An apparatus for measuring foot forces during walking uses a specially configured spring seated in a transducer plate to transmit static and dynamic forces on the foot during walking to strain gauges mounted on the transducer plate, which, in turn, may be monitored and recorded for diagnostic purposes, particularly to aid in treating patients with lower extremity dysfunction.

Abstract: A device for signaling a patient when a predetermined load is placed on the patient's foot comprises a resilient foot pad having a toe end and a heel end and adapted to substantially cover the inner sole of a shoe. A resilient liquid filled tube is mounted within the pad with the tube extending from adjacent the toe end to adjacent the heel end of the pad. A signaling device is controlled by a pressure responsive means in communication with the liquid in the tube for the actuation of the signaling means at a predetermined pressure of said liquid.