Installation for assembling tube components, particularly bodies (1) with shoulders, comprising the following elements arranged in succession: a linear body conveyor (4), a transfer system (7) designed to apply a change in orientation to the bodies (1) of about 90°, an assembly unit (8) for fixing the shoulders to the bodies (1), characterized in that the transfer system (7) consists of a device (9) for gripping the bodies and of a device (17) for changing the orientation of the bodies, the orientation-change device comprising a rotary conveyor (17), of the conveyor belt type, which is arranged at right angles to the direction of the linear conveyor (4), the said rotary conveyor (17) comprising a belt (18, 19) rotating about a direction that makes an angle of about 45° with the direction of the linear conveyor (4), the belt (18, 19) comprising elements (15) for grasping the bodies, the shape of which is designed so that the bodies (1) are initially grasped on one of the sides of the rotary conveyor (17), in a direction parallel to that of the linear conveyor (4), and that they undergo a change in orientation by 90° when they pass to the other side of the rotary conveyor (17).