The invention relates first to a device for applying a pressing force, comprising two pressing jaws (25, 26) which can be moved linearly relative to each other via a hydraulic piston-cylinder assembly (8). Additionally, an actuation cone (13) is provided for an expanding device (36), said cone carrying out a forward and rearward movement depending on an actuation of the hydraulic piston-cylinder assembly (8). In order to advantageously develop the device, the actuation cone (13) is connected to the hydraulic piston (9) of the hydraulic piston-cylinder assembly (8) for the forward and rearward movement. The invention further relates to a device for applying a pressing force, comprising two pressing jaws which can be moved linearly relative to each other and which can be held in receiving areas and to a pair of pressing jaws.