Safety mechanism at a tow tearing machine has a connecting linkage from the lever at the upper pressure roller to a safety/control unit with an alarm/stop switch tripped on a build-up shift at the upper roller
The safety system at a tearing machine, to break continuous tow into lengths, registers material winding round the upper pressure rollers (1) and/or the lower cylinder (2). It is an electromagnetic system, with an automatic reassertion. It has a connection (8) with the lever (3) which carries the upper pressure roller (1), linked to a lever (6) which shifts the upper pressure roller (1) against the lower pressure cylinder (2), at a safety and control unit (7) which shuts down the machine. The lever (6) to transmit the shifting movement is linked (8) to the roller carrier lever (3), and pivots on the machine frame (4). The connector (8), between the two levers (6,8), is a lever (13) which pivots on the machine frame (4). The connecting end at the roller lever (3) has a sliding guide (14), and a friction coupling (15) is at the end linked to the transmission lever (6) to allow a counter swing movement at the levers (13,6). The structure prevents an overload at the connected units or the linkage between them. The friction coupling (15) is an assembly of friction surfaces at the ends of the levers (13,6) as a disk clutch tensed by one or more springs. The safety and control unit (7) has an alarm and control switch (7') operated by the end of the transmission lever (6), through the shifting movement of the pressure roller (1) which is transferred into a lever (6) movement. An adjustable limit stop (10) allows a normal passage for a textile fabric between the upper pressure roller (1) and the lower pressure cylinder (2), located near the switch (7'). The reassertion unit (12) is a cylinder, and the like, acting on the end of the lever (6) near the switch (7'). A time unit sets the duration of the reassertion unit (12) action, as a magnetic valve used to fill the cylinder, controlled by a program or a clock. An additional alarm (11) is fitted to the machine frame (4) at a gap from the end of the lever (3) to carry the roller. The gap is larger than the thickness of the material passing through plus the max. permissible build-up on the roller (1) or cylinder (2). The levers (13,6) of the connector (8) move with the shifts of the upper pressure roller (1). The control (7) to stop the machine is at the adjustable limit stop (10), within the length dimensions of the lever (3) at the roller (1).
