A driver assembly (50) for an introducer assembly (10) for the deployment of an implantable medical device (16) includes a sprung element (52) coupled to a yoke (56). The yoke (56) is coupled to a gripper element (58). The yoke (56) is coupled to a first handle unit (30) of the introducer (10). The sprung element (52) is coupled to a proximal handle unit (32). A brake element (66) acts to prevent operation of the sprung element (52) when no manual force is being applied to attract a sheath (24) and the assembly (10). When manual retraction force is applied to the assembly (50) the gripper element (58) the brake element (66) releases a sprung element (52) so that the lighter can apply a force assistance to assist in the retraction of the sheath (24) and thereby to assist in the deployment of a medical device.
