US Patent 7866971 Coupling for a plastics injection molding machine

A coupling for a plastics injection molding machine which connects a drive shaft to a screw comprises at least one force sensor with a measuring element for the indirect determination of the nozzle pressure. The coupling comprises a first connection which has torsional strength and does not transfer axial force. The coupling comprises a second connection, which is mechanically uncoupled from the first connection and is compression proof and does not transfer torque between the drive shaft and the feed screw. The measuring element is arranged in the force path A of the second compression proof connection but is not also in the force path T of the first connection. Thus, during operation, measurements in the measuring element are not falsified by torsional forces.