Safety device for flat-bed knitting machines

A safety device for flat-bed knitting machines having at least one needle bed, piezoelectric oscillation pickups secured to each needle bed, at least one cam carriage and drive means, for stoppage of the machine in the event of a change occurring in the mechanical load of the needle beds as determined by the pickups as a consequence of impacts or the like as compared with the applicable normal operation, comprising:

• a central processing unit;
• an adjustable comparator device associated with each needle bed;
• and
• a shutoff device, wherein:
• each needle bed is provided on both of its long ends with a piezoelectric oscillation pickup;
• each piezoelectric oscillation pickup of a needle bed is associated with the adjustable comparator device f that needle bed, and with the outputs from each piezoelectric oscillation pickup being connected to its associated adjustable comparator device;
• the central processing unit receives actual values of the mechanical load on each needle bed as a load-proportional variable, and each adjustable comparator device receives the actual values associated with its needle bed;
• and
• the central processing unit generates threshold values received by the appropriate adjustable comparator device where a comparison is made with the actual values received and a shutoff signal generated which triggers the shutoff device for stopping the machine.

A safety device, in particular for flat-bed knitting machines having at least one needle bed, piezoelectric oscillation pickups secured to each needle bed, at least one cam carriage and drive means for stoppage of the machine in the event of a change occurring in the mechanical load of the needle beds as determined by the pickups as a consequence of impacts or the like as compared with the applicable normal operation and/or in the power to the carriages as compared with applicable normal operation resulting from disruptions in removal of the goods, in loop formation and yarn insertion, or caused by the specification of excessively high loop tightness or the like, comprising:

• a measuring means for detecting the actual value of a torque-proportional variable associated with the drive means;
• an adjustable comparator device associated with each needle bed, each needle bed being provided on both of its long ends with a piezoelectric oscillation pickup, each piezoelectric oscillation pickup of needle bed being associated with an adjustable comparator device of that needle bed, and with the outputs from each piezoelectric oscillation pickup being connected to its associated adjustable comparator device;
• a central processing unit for receiving the actual values of the torque-proportional variable and for generating threshold values of the torque-proportional variable, and for receiving actual values of the mechanical load on each needle bed as a load-proportional variable, each adjustable comparator device receiving the actual values associated with its needle bed, and generating threshold values received by the appropriate adjustable comparator device where a comparison is made with the actual values received and a shutoff signal generated;
• a further adjustable comparator device for receiving the actual values of the torque-proportional variable and the threshold values, said actual values and said threshold values being compared and a shutoff signal generated;
• and
• a shutoff device triggered by either shutoff signal for stopping the machine.