Load cell

Abstract: Principles of a varied group of new semiconducting, piezoresistive stress and strain transducers are outlined. These devices have in common the utilization of the transverse or shear piezoresistive effect. One group of devices consists of gauges in the form of a thin rectangular sheet which is bonded to the test piece, and whose resistance change can be expressed as a simple function of the principal stresses in the gauge. Two special gauges in this group are described. In one, the resistance change is proportional to the sum of the principal biaxial stresses for any orientation of the gauge on the test piece. In the other, the resistance change is proportional only to longitudinal stress components, being independent of transverse stress components. Also described are: a four‐terminal gauge for complete determination of biaxial stresses, full‐bridge gauges made from a single crystal, load cells of low compliance, new torque transducers, and diffusion techniques for making some of the foregoing. The devic...

Abstract: An apparatus (10) that utilizes microelectromechanical systems (MEMS) technology to provide an in vivo assessment of loads on adjacent bones (24 and 26) comprises a body (34) for insertion between the adjacent bones. At least one sensor (42) is associated with the body (34). The sensor (42) generates an output signal in response to and indicative of a load being applied to the body (34) through the adjacent bones (24 and 26). A telemetric device (40) is operatively coupled with the sensor (42). The telemetric device (40) is operable to receive the output signal from the sensor (42) and to transmit an EMF signal dependent upon the output signal. According to various aspects of the invention, the sensor comprises a pressure sensor (42), a load cell (320), and/or at least one strain gauge (142).

Abstract: An ultrasound indentation system for biomechanical assessment of soft tissues in vivo was developed. The pen-size, hand-held probe was composed of an ultrasound transducer and a load cell. The ultrasound transducer was at the tip of the probe serving also as the indentor. The thickness and deformation of the soft tissue layer were determined from the ultrasound echo. A compressive load cell was connected in series with the ultrasound transducer to record the force response. A validation experiment was performed on porcine tissues. Force and deformation acquired with the present system was in good comparison with those obtained from a Housfield material testing machine. Material constants were obtained via a curve-fitting procedure by predicting the force transient response from the deformation-time data using a quasilinear viscoelastic model. In addition, deformation in the fat and in the muscle could be differentiated. The potential applications of this type of indentation probes are many. The specific application of this current development is for stump tissue assessment in the design of prosthetics.

Abstract: Soft actuators driven by pneumatic pressure are promising actuators for mechanical systems in medical, biological, agriculture, welfare fields and so on, because they can ensure high safety for fragile objects from their low mechanical impedance. In this study, a new rubber pneumatic actuator made from silicone rubber was developed. Composed of one chamber and one air-supply tube, it can generate curling motion in two directions by using positive and negative pneumatic pressure. The rubber actuator, for generating bidirectional motion, was designed to achieve an efficient shape by nonlinear finite element method analysis, and was fabricated by a molding and rubber bonding process using excimer light. The fabricated actuator was able to generate curling motion in two directions successfully. The displacement and force characteristics of the actuator were measured by using a motion capture system and a load cell. As an example application of the actuator, a robotic soft hand with three actuators was constru...