PACKAGE STRAPPING MACHINES

A strapping machine for binding packages with metal or plastics strapping has a tensioning device which is driven by an electric motor more instead of the more usual air motor. The electric motor is coupled to the tensioning device by a hydro-dynamic coupling which delivers maximum torque with its output stalled but while its input is still rotating and such that the motor is not overloaded even though the tension is maintained for an appreciable time. The maximum output of the hydro-dynamic coupling can be adjusted by altering the quantity of hydraulic fluid it contains either initially or by a fluid control circuit which causes fluid to flow into or out of the working chamber of the coupling to alter the amount of fluid it contains.