Apart from transmitting the torque the demand on a torsionally; flexible cardan shaft connecting coupling is higher torsional; flexibility to ensure that the main critical speed of the machine can be; shifted far below the idle-running speed. BoWex-ELASTIC® type HEG has a maintenancefree plain bearing to absorb; the radial loads produced by the cardan shaft. Moreover, the coupling; includes a friction disk which is prestressed axially by means of the; elastomer part. The elastomer part is produced from natural rubber; during a vulcanizing process. ; Due to the permanent friction the; coupling has excellent damping properties, reducing the high alternating; loads arising in the coupling considerably when starting and passing; through the resonance. In addition the BoWex-ELASTIC® HEG shall have good damping properties; in the resonant range, i. e. when passing through the resonance, in; order to keep the high coupling loads that arise as low as possible. The elastomer part and the friction disk in the coupling operate in; parallel with each other. The friction disk reduces torque peaks at a; high extent, i. e. converting into heat. The heat generated is; dissipated through the metallic components. As a consequence a heat; accumulation in the elastomer part produced during the frequent starting; of the diesel engine and the resulting high load on the coupling is; avoided. In this way the expected lifetime of the coupling is extended; considerably. ; Couplings type BoWex-ELASTIC® HEG are supplied as; an assembled, pre-set unit. After the coupling has been mounted to the; flywheel, the cardan shaft can be assembled.