Abstract: The apparatus comprises a pair of parallel conveyors (T1, T1′) with vertical motorized axes (101, 101′), formed by any flexible heat-resistant and air-permeable structure, the inside run of which contacts with appropriate pressure the sides, containing the folded-down flaps to be sealed, of the packaging (P), which is supported from beneath by for example an optional horizontal motorized conveyor (T) travelling in the same direction and at the same speed as the said inside runs of the said lateral conveyors arranged longitudinally behind which are tubular electrical resistors (6, 6′) heatable by the joule effect and of low thermal inertia, that dispense jets of hot air through the active inside runs of these conveyors and that are incident upon the flaps of the packagings, in order to produce weld lines thereon. Subsequent means (10, 10′) are provided to maintain an appropriate pressure and to cool the said weld lines, before the packagings leave the said apparatus.

Abstract: The lower folders (P1, P2) of the packaging machine are driven by a rod and crank system (1, 2) moved by an electric motor (5) with control of speed and phase, regulated by an electronic processor (7) with a corresponding programming and dialogue unit (8). The rod and crank system is designed and arranged in such a way that, when the folders are closed, the rod (1) is aligned with the crank (2), and this position (K) is taken to be the zero position by the said processor and is detected for this purpose by a sensor (6). To drive the folders through a complete cycle of closing and opening, the motor (5) has to execute only one pulse, to transfer the rod and crank system from one to the other of two limit positions (K1, K2), spaced apart from the said zero position by an identical distance which is variable, according to the format of the products to be packaged, by means of the said programming unit (8).

Abstract: At least one driving sprocket (H1) and the neighbouring driven sprocket (H2) carrying the two pairs of chains of the compartment conveyor (T) are connected to each other by means of a dog clutch (2, 4) operated by an actuator (15) controlled by the control panel (19) of the packaging machine. The driving shaft (L) on which the said sprockets (H1, H2) are mounted is turned by an electric motor (1) of the electronic speed and phase control type.

Abstract: The machine comprises a main carousel including a horizontal axis having seats which are angularly equidistant and open outwardly and including at the front a gripper and at the rear a folding device. Each seat passes first adjustable means with the gripper open to supply the gripper with a packaging sheet arranged on the seat, and cooperating with a first auxiliary carousel which inserts a roll into each seat, oriented with its axis parallel to that of the main carousel, while the roll is partially wrapped with the packaging sheet retained by the closed gripper. In succession, the rear folding device intervenes and the gripper opens and folding means intervene in order to fold the front edge of the sheet onto the rear edge, while the folding device returns to the rest position and the edges are fixed together by a heat-sealing carousel.