Intermittent web feed apparatus
First Claim
1. A web sealing apparatus having an intermittent web feed unit for intermittently feeding a web into a seal unit and holding said web stationary during the actuation of said seal unit, comprising cycle means for periodically actuating of said seal unit including an operative period during which said seal unit is actuated to engage said web and an inoperative period during which said seal unit is spaced from said web and establishes an available time of an indexing cycle for movement of the web through said seal unit, wherein said cycle means comprises a machine cycle means operative in timed relation to the seal unit and the web feed unit to establish successive machine cycles, a machine cycle reference means coupled to said machine cycle means and establishing reference signals related to the operative and inoperative periods of the seal unit, a servo motor means coupled to said feed unit, a feedback signal means coupled to said servo motor means establishing an output signal corresponding to the position of said motor means, web length means providing a feed output signal proportional to the length of web to be fed through said seal unit during said inoperative period, a controller including a processor having an operative program operable to read said machine cycle reference means and determine the available time of said inoperative period and read said web length means and determine the length of the web to be fed through said seal unit during said available time and calculate a profile program producing a profile signal for energization of said motor means including controlled acceleration to a top speed and a controlled deceleration from said top speed whereby said web is moved through said machine within said available time.
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Accused Products
Abstract
A bag machine includes a programmed logic controller intermittently actuating a web feed draw roll motor for controlled web feed during the inoperative period of a cycled seal bar. The controller has separate inputs for the seal bar periods and a web length and establishes a control program of a preferred motion profile, with acceleration and deceleration of the fixed rolls to match the bag length to the available time using the total time available, with acceleration to a maximum and deceleration to reference, with or without a constant speed period. The bag length and time is monitored each machine cycle to calculate the next motion profile and permit changes in the bag length without machine shut-down. A programmed registered mode of control responds to a web mark spacing relative to the seal bar. In the registered mode, a photoscanner detects the mark during a constant speed web feed period prior to the end of the available time and actuates the web feed accordingly. If actual draw roll motion differs from the programmed motion profile, a fault signal may shut-down the machine. Manual control and inputs are provided for setup and for manual machine operations. The controller may vary the length of every other bag slightly to spaced hot seams from each other and permits stacking of the bags. A programmed reverse drive withdraws the web slightly from the seal bar to prevent sticking of the web to the seal bar.
47 Citations
26 Claims
- 1. A web sealing apparatus having an intermittent web feed unit for intermittently feeding a web into a seal unit and holding said web stationary during the actuation of said seal unit, comprising cycle means for periodically actuating of said seal unit including an operative period during which said seal unit is actuated to engage said web and an inoperative period during which said seal unit is spaced from said web and establishes an available time of an indexing cycle for movement of the web through said seal unit, wherein said cycle means comprises a machine cycle means operative in timed relation to the seal unit and the web feed unit to establish successive machine cycles, a machine cycle reference means coupled to said machine cycle means and establishing reference signals related to the operative and inoperative periods of the seal unit, a servo motor means coupled to said feed unit, a feedback signal means coupled to said servo motor means establishing an output signal corresponding to the position of said motor means, web length means providing a feed output signal proportional to the length of web to be fed through said seal unit during said inoperative period, a controller including a processor having an operative program operable to read said machine cycle reference means and determine the available time of said inoperative period and read said web length means and determine the length of the web to be fed through said seal unit during said available time and calculate a profile program producing a profile signal for energization of said motor means including controlled acceleration to a top speed and a controlled deceleration from said top speed whereby said web is moved through said machine within said available time.
- 16. A web processing apparatus comprising a seal bar unit, cycle means for periodically actuating said seal bar unit including an operating period during which said seal bar unit is actuated to engage said web and a dwell period during which said seal bar unit is spaced from said web and defining an available time of an indexing cycle for movement of the web through said seal bar unit, draw feed roll units coupled to said web for moving said web relative to said seal bar unit, rotating shaft means operating in timed relation to the seal bar unit and the draw roll units and establishing a machine cycle during each revolution of said rotating shaft means, a switch actuator coupled to and rotated by said shaft means, first and second switch means mounted adjacent said switch actuator and coupled thereto during each revolution of said shaft means, said first and second switch means being circumferentially spaced for actuation in synchronism with the movement of the seal bar unit at the beginning of said operating period and in synchronism with the ending of said operating period and thereby establishing reference signals related to the operating period of the seal bar unit and the dwell period of said seal bar unit, a servo motor directly coupled to said draw feed roll units, a feedback means coupled to said motor and establishing an electrical output signal corresponding to the position of said motor, a web length input for providing an electrical output signal proportional to the length of web to be fed through said seal bar unit during said dwell period to form a bag, a position controller including a processor having an operating program operable to read said switches and determine the available time of said dwell period and read said length input to determine the length of web to be fed through said seal bar unit during said available time and calculate a motion profile signal for energization of said motor including a controlled acceleration to a top speed and a controlled deceleration from said top speed whereby said web is moved through said machine within said available time.
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26. A web processing apparatus for moving a continuous web through a work station, comprising a work unit, an operating cycle time including an inoperative dwell period and a work period, said work period being of an adjustable work length time within said cycle time and establishing a related adjustable dwell length time, web moving means coupled to support and move said web and including a stop position supporting said web in said work unit during said work period and a driving position transporting said web through said work unit during said dwell period, an electrical motor means coupled to said web moving means and holding said web stationary and rapidly accelerating said web moving means from a reference position for moving said web into said work unit, control means including signal means to energize said motor means with controlled acceleration and deceleration within said dwell period with a programmed motion profile and establishing controlled acceleration and deceleration of said motor means to move said web during the adjustable dwell length time, said control means including first input means including a bag length input and second input means for said adjustable dwell length time to establish said programmed motion profile for continuously moving said web from the beginning to the end of said dwell length time and said control means monitoring the movement of said web and varying said motor means in accordance with said motion profile to maintain said motion profile in accordance with said bag length input and said dwell length time input.
Specification