The disclosure relates to a power-transfer unit for a sealing unit of a packaging machine comprising a support, intended to be attached to a sealing unit, a power bar comprising a contact-initiation section, a contact-termination section, and an intermediate section therebetween, the power bar being resiliently suspended in the support and being movable along a first direction being normal to a contact surface of the intermediate section. The power bar is suspended in the support by a first leaf spring.