Drive motor controlling apparatus for use in packaging machine

An apparatus for use in a packaging machine for controlling the operations of a film transportation motor for transporting a continuous elongated film web through a tube forming means to form the film web into a continuous film tube, an article feeding motor for feeding articles to be packaged into the film tube at equidistant intervals from an entrance side of the tube forming means, a frame driving motor for reciprocating a frame in the same direction as the transportation of the film tube on an exit side of the tube forming means, said frame supporting a pair of sealers, and a sealer opening-closing motor for opening and closing the pair of sealers to cross seal the film tube between adjacent articles to be packaged, said sealer opening-closing motor being mounted on the frame, rotational speeds of said motors being controlled to interrelate with each other, said apparatus comprising:

• a timing means for outputting a signal for every rotation of a shaft of the frame driving motor;
• a rotational angle division detecting means for outputting a multiplicity of pulse signals by subdividing an rotational angle of the shaft of the frame driving motor;
• a cycle determining means for determining a cycle of the frame driving motor based on a reference pulse generated by a reference pulse generator for generating micropulse pulses;
• a means for determining a rotation cycle of each of the four motors based on respective data outputted from the rotational angle division detecting means and the cycle determining means;
• a means for determining a cyclic variable speed of the frame driving motor based on numerical data on the size of articles to be packaged inputted from an input device, by comparing the pulse outputted from the rotational angle division detecting means with the reference pulse generated by the reference pulse generator;
• and
• a cycle offset correcting means for correcting cycle offsets of the film transportation motor and the article feeding motor by comparing pulses outputted from encoders respectively connected to the film transportation motor and the article feeding motor with the signal outputted from the timing means.