Control apparatus for trailing edge folder in carton folding machine

Apparatus for controlling the operation of a trailing edge folder in a blank folding machine having conveyor means for continuously advancing blanks with trailing panels in a predetermined direction in untimed relationship to one another along a generally horizontal path, said folder having a rotatable shaft mounted below said path and transverse thereto, shaft operating means for rotating and stopping said shaft intermittently after at least one respective response time delay, and arm means mounted on said shaft and extending generally radially therefrom, said arm means having folding head means at the distal end thereof for folding over the respective trailing panel of each of said blanks, said control apparatus comprising:

• blank sensing means, responsive to the presence of a blank at a predetermined location along said path upstream of said folder, for producing a trailing edge signal when the trailing edge of the blank leaves said location;
• panel length advance means, responsive to an input signal to said panel length advance means, for producing a panel length output signal at the end of an interval after said input signal which interval is substantially complementary to the length of said trailing panel;
• response time advance means, responsive to an input signal to said response time advance means, for producing a response time output signal at the end of an interval after said input signal which interval is substantially complementary to one of said respective response time delays of said shaft operating means;
• means for applying said trailing edge signal as an input signal to one of said panel length advance means and said response time advance means;
• means for applying the output signal of one of said panel length advance means and said response time advance means as an input signal to the other of said panel length advance means and said response time advance means to develop a first advance control signal at the end of an interval after said trailing edge signal which is substantially the sum of said interval substantially complementary to said panel length and said interval substantially complementary to one of said respective response time delays;
• first advance control means, responsive to said first advance control signal, for causing said shaft operating means with at least one respective response time delay to rotate said shaft so that said folding head means moves generally in said predetermined direction to fold over said trailing panel;
• first position sensing means, responsive to the rotation of said shaft to a first predetermined position, for producing a first position signal indicative thereof;
• means for applying said first position signal as an input signal to said response time advance means to develop a respective response time output signal as a first stop control signal;
• first stop actuating means, responsive to said first stop control signal, for causing said shaft operating means with at least one respective response time delay to stop said shaft;
• pause means, responsive to said first stop control signal and the operation of said conveyor means, for developing a second advance control signal at the end of a predetermined pause interval after said first stop control signal;
• second advance control means, responsive to said second advance control signal, for further causing said shaft operating means to rotate said shaft after said predetermined pause interval;
• second position sensing means, responsive to the further rotation of said shaft to a second predetermined position, for producing a second position signal indicative thereof;
• means for applying said second position signal as an input signal to said response time advance means to develop a respective response time output signal as a second stop control signal;
• second stop actuating means, responsive to said second stop control signal, for causing said shaft operating means with at least one respective response time delay to stop said shaft in a dwell position where said folding head means is clear of said path;
• and
• jam detection means for indicating that said shaft is not moving freely, said jam detection means comprising a jam counter having a clock input terminal, means for applying clock pulses to said clock input terminal of said jam counter at a rate which is indicative of the operating speed of said folding machine, means for producing a jam output signal upon the counting of a predetermined number of clock pulses, and means responsive to one of said first and second position signals for stopping said jam counter prior to said predetermined number when said shaft is moving sufficiently freely that a respective one of said first and second positions is reached prior to the counting of said predetermined number of clock pulses.

Apparatus for controlling the operation of a trailing edge folder in a blank folding machine having conveyor means for continuously advancing blanks with trailing panels in a predetermined direction in untimed relationship to one another along a generally horizontal path, said folder having a rotatable shaft mounted below said path and transverse thereto, shaft operating means for rotating and stopping said shaft intermittently after at least one respective response time delay, and arm means mounted on said shaft and extending generally radially therefrom, said arm means having folding head means at the distal end thereof for folding over the respective trailing panel of each of said blanks, said control apparatus comprising:

• blank sensing means, responsive to the presence of a blank at a predetermined location along said path upstream of said folder, for producing a trailing edge signal when the trailing edge of the blank leaves said location;
• panel length advance means, responsive to an input signal to said panel length advance means, for producing a panel length output signal at the end of an interval after said input signal which interval is substantially complementary to the length of said trailing panel;
• response time advance means, responsive to an input signal to said response time advance means, for producing a response time output signal at the end of an interval after said input signal which interval is substantially complementary to one of said respective response time delays of said shaft operating means;
• means for applying said trailing edge signal as an input signal to one of said panel length advance means and said response time advance means;
• means for applying the output signal of one of said panel length advance means and said response time advance means as an input signal to the other of said panel length advance means and said response time advance means to develop a first advance control signal at the end of an interval after said trailing edge signal which is substantially the sum of said interval substantially complementary to said panel length and said interval substantially complementary to one of said respective response time delays;
• first advance control means, responsive to said first advance control signal, for causing said shaft operating means with at least one respective response time delay to rotate said shaft so that said folding head means moves generally in said predetermined direction to fold over said trailing panel;
• first position sensing means, responsive to the rotation of said shaft to a first predetermined position, for producing a first position signal indicative thereof;
• means for applying said first position signal as an input signal to said response time advance means to develop a respective response time output signal as a first stop control signal;
• first stop actuating means, responsive to said first stop control signal, for causing said shaft operating means with at least one respective response time delay to stop said shaft;
• pause means, responsive to said first stop control signal and the operation of said conveyor means, for developing a second advance control signal at the end of a predetermined pause interval after said first stop control signal;
• second advance control means, responsive to said second advance control signal, for further causing said shaft operating means to rotate said shaft after said predetermined pause interval;
• second position sensing means, responsive to the further rotation of said shaft to a second predetermined position, for producing a second position signal indicative thereof;
• means for applying said second position signal as an input signal to said response time advance means to develop a respective response time output signal as a second stop control signal;
• second stop actuating means, responsive to said second stop control signal, for causing said shaft operating means with at least one respective response time delay to stop said shaft in a dwell position where said folding head means is clear of said path;
• and
• an overenergizer circuit for decreasing said respective response time delays by momentarily increasing the power applied to one of said first and second advance control means and to said first and second stop actuating means causing said shaft to rotate and stop, respectively.