Web supply mechanism for an indexing motion packaging machine

A packaging apparatus, comprising:

• an indexing motion advancement mechanism for advancing a web through a series of stations which form the web into a component of a package;
• and
• a web supply mechanism for supplying the web to the advancement mechanism, comprising:
• a web unwind mechanism for unwinding the web from a supply roll and supplying the web to the advancement mechanism, comprising an unwind motor and a nip roll arrangement with which the web is engaged, wherein the motor is drivingly engaged with at least one drive roller associated with the nip roll arrangement, wherein the nip roll arrangement includes a pair of drive rollers with which the motor is drivingly engaged, with the drive rollers being spaced from each other, and a nip roller located between the drive rollers and engaged with each drive roller, wherein the web is wrapped about the nip roller and is engaged with the nip formed by the nip roller with each drive roller;
• and
• a take-up mechanism interposed between the web unwind mechanism and the advancement mechanism for maintaining tension in the web upstream of the advancement mechanism.

For a packaging apparatus including an indexing motion advancement mechanism for advancing a web through a series of stations which form the web into a component of a package, a web supply mechanism for supplying the web to the advancement mechanism, comprising:

• a web unwind mechanism for unwinding the web from a supply roll and supplying the web to the advancement mechanism, comprising a variable speed unwind motor and a nip roll arrangement with which the web is engaged, wherein the motor is drivingly engaged with at least one drive roller associated with the nip roll arrangement;
• and
• a take-up mechanism interposed between the web unwind mechanism and the advancement mechanism and interconnected with the unwind motor to control its operation for maintaining tension in the web upstream of the advancement mechanism, the take-up mechanism comprising a switch interconnected with the motor for selectively supplying and cutting off power to the motor and for controlling the speed of operation of the motor;
• an arm to which a take-up roller is mounted, wherein the arm is movable in response to movement of the take-up roller;
• and an actuator member mounted to the arm, wherein the position of the actuator member controls the supply of power to the motor and also the speed of operation of the motor.

A method of supplying a web to an indexing motion web advancement mechanism, comprising the steps of:

• unwinding the web from a supply roll during indexing advancement of the web by the advancement mechanism by operation of an unwind motor driving one or more drive rolls associated with a nip through which the web passes;
• maintaining tension in the web upstream of the advancement mechanism by operation of a take-up mechanism;
• and
• varying the rate of the unwinding of the web from the supply roll through the take-up mechanism and the unwind motor by selectively cutting off supply of power to the unwind motor and supplying power to the unwind motor in a manner which controls the speed of operation of the unwind motor, responsive to the take-up mechanism, to accommodate the indexing advancement of the web while tension is maintained in the web upstream of the advancement mechanism by the take-up mechanism.