Ultrasonic welding system having a holder

An ultrasonic welding installation comprising an ultrasonic welding unit having a sonotrode and a converter, wherein the sonotrode (1) and the converter (3) are arranged along a longitudinal axis and the ultrasonic vibration unit can be caused to resonate with an ultrasonic vibration in the direction of the longitudinal axis with a wavelength λ wherein there is provided a holder (5) for holding the ultrasonic vibration unit, wherein the holder (5) has a clamping device which is reciprocable between an opened position in which the ultrasonic vibration unit can be removed from the holder (5) and a closed position in which the clamping device comes into contact with the ultrasonic vibration unit and exerts a force on same so that the ultrasonic vibration unit is held, characterised in that the clamping device is in the form of a sleeve having an inner and an outer surface, wherein the inner surface is of a configuration corresponding to an outer surface of a portion of the ultrasonic vibration unit, wherein the sleeve has a slot which connects the outer surface of the sleeve to the inner surface of the sleeve so that the sleeve has two mutually opposite slot walls (33, 34) which define the slot, wherein there is provided a tightening device with which the slot walls (33, 34) can be moved towards each other whereby the clamping device is moved into the closed position and the space enclosed by the inner surface is reduced and the ultrasonic vibration unit is clamped within the sleeve.