TE 89 HIP & KNEE JOINT FRICTION SIMULATOR

Overview

The TE 89 HIP & KNEE JOINT FRICTION SIMULATOR comprises two support systems for hip and knee joint components; hip joints are inverted and the acetabular cup or tibial plate is mounted in a low friction trunnion-mounted reservoir carried in a loading frame, while the femoral component is mounted on the underside of a rigid cross-beam that is oscillated through an adjustable pre-set angle and a jig ensures the femoral component is oscillated about its centre and aligned with the lower test piece. Load is applied by a high duty linear solenoid acting through a 9:1 lever to the carriage that supports the trunnion-mounted reservoir, and load is measured by a piezo-electric force transducer mounted centrally on the carriage. The trunnion bearings can be driven to increase their load carrying capacity and reduce parasitic friction; by driving the bearings in opposite directions the parasitic torque transmitted to the trunnion assembly substantially cancels out, with a parasitic torque of about 10% of the smallest measured friction torque expected. The trunnion-mounted assembly is restrained from rotation by a piezo-electric force transducer carried on the lower loading carriage and connected by a flexure link. Two reservoirs are provided, one for the acetabular cup and one for the tibial plate, and tests may be run dry or lubricated with water, synthetic lubricants and synovial fluid. The cross beam carrying the femoral component is carried in bearings aligned with the axis of the lower trunnion-mounted assembly; these bearings are carried on brackets mounted on linear ball slides which allow correct location and locking. The beam is oscillated sinusoidally through a crank mechanism with an adjustable throw and minimized arm and crank mass, and the drive arrangement comprises a thyristor-controlled dc gear motor with tachogenerator feedback; timing between the load on/off action and the oscillating action is adjusted by an optical sensor and adjustable trigger to permit position and duration adjustment and to allow the load to be applied on either the forward or reverse strokes. Key specifications: - Load Range: 200 to 2,500 N - Load Sensor: piezo-electric transducer - highest sensitivity (Load Sensor): 10 mN - highest range (Load Sensor): 7,500 N - Frequency Range: 0.02 to 1 Hz - Oscillating Angle: 0 to +/- 35 degrees - Friction Sensor: piezo-electric transducer - highest sensitivity (Friction Sensor): 1 mN - highest range (Friction Sensor): 500 N - Maximum Knee Size: 85 mm wide - Interface: Phoenix Tribology USB micro-controller interface - Software: COMPEND 2020 - Controlled Parameters: Applied Load; Rotational Speed (Frequency); Number of Cycles; Test Duration - Measured Parameters: Applied Load; Rotational Speed (Frequency); Frictional Torque; Number of Cycles; Test Duration - Electricity: 220/240V, single phase, 50 Hz, 3 kW; 110/120 V, single phase, 60 Hz, 3 kW - Bench-mounting machine: 580 mm wide x 560 mm deep x 560 mm high - Bench-mounting cabinet: 540 mm wide x 540 mm deep x 450 mm high - Packing Specifications: 1.73 m3, GW 270 kg, NW 230 kg The TE 89 is used to apply defined load cycles in a predictable and repeatable fashion and to measure very low levels of friction generated within lubricated hip and knee joints. It supports testing of acetabular cups and tibial plates with the femoral component oscillated through adjustable angles, and tests may be run dry or lubricated with water, synthetic lubricants and synovial fluid. Control and data acquisition are implemented via a host PC running COMPEND 2020 with a Phoenix Tribology USB micro-controller interface, enabling user-programmable test sequences or manual on-screen toggles and storing data to hard disc in .csv or .tsv file formats while measuring applied load, rotational speed (frequency), frictional torque, number of cycles and test duration.