Intermittent web drive mechanism employing unidirectional clutches

Claim 2

Means for intermittently advancing a web of flexible film comprising: a. drive means for imparting repeating cycles of intermittent motion and dwell to said web with the motion normally being along a certain predetermined web direction, said drive means including output shaft means having first and second input driver means operatively coupled thereto; b. input shaft means and means for drivably rotating said input shaft in one rotational direction; c. unitary output shaft means adapted to be operatively coupled to said web for imparting motion thereto; d. first and second driver means arranged in phased relationship one-to-another and being responsive to the rotation of said input shaft means and operatively coupled to said output shaft for drivably rotating said output shaft in one rotational direction, each driver means being effective for the rotation of said output shaft for a driving cycle of said output shaft, with continuously varying rates of rotational velocity having acceleration from dwell to maximum velocity and deceleration from maximum velocity to dwell, and further being effective only during one-half of each rotational cycle imparted to each of said driver means by said input shaft; e. means including first unidirectional clutch means intercoupling said first driver means to said input and output shafts for initiating rotation of said output shaft and for continuing said rotation for a first motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said first driver means at the end of said first motion segment; f. means including second unidirectional clutch means for intermittently inter-coupling said second driVer means to said input and output shafts in phased relationship to said first driver means and for achieving over-riding de-coupling of said first driver means from said output shaft for continuing rotation of said output shaft for a second motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said second driver means upon completion of said second motion segment; and g. means for maintaining said output shaft means in locked disposition while said first driver means and said second driver means are simultaneously de-coupled from said output shaft to impart a dwell cycle to said web.

Claim 3

The apparatus as defined in claim 1 being particularly characterized in that said first and second motion segments are substantially equal.

Claim 4

The apparatus as defined in claim 1 being particularly characterized in that said first and second driver means are arranged in phased relationship one-to-another by an arcuate distance of less than 180*.

Claim 5

The apparatus as defined in claim 1 being particularly characterized in that brake means are coupled to said output shaft means, and means are provided for energizing said brake means for that dwell portion of the cycle remaining after termination of said first and said second motion segments.

Claim 6

The apparatus as defined in claim 1 being particularly characterized in that said first and second driver means are in phased relationship, one-to-another by an arcuate distance of between 45* and 165*.

Claim 7

The apparatus as defined in claim 1 being particularly characterized in that said first and second driver means are rack-and-pinion drivers.

Claim 8

The apparatus as defined in claim 6 being particularly characterized in that said rack-and-pinion driver means are disposed on opposite ends of said input and output shafts.

Claim 9

Thermoplastic web treating apparatus comprising, in combination, drive means for intermittently advancing superimposed webs of thermoplastic sheet film material and for stopping said superimposed webs for a pre-determined period of dwell, and hot knife means for thermally welding said superimposed webs together at predetermined spaced intervals therealong, said drive means comprising: a. drive means for imparting repeating cycles of intermittent motion and dwell to said web with the motion normally being along a certain pre-determined web direction, said drive means including output shaft means having first and second input driver means operatively coupled thereto; b. input shaft means and means for drivably rotating said input shaft in one rotational direction; c. unitary output shaft means adapted to be operatively coupled to said web for imparting motion thereto; d. first and second driver means arranged in phased relationship one-to-another and being responsive to the rotation of said input shaft means and operatively coupled to said output shaft for drivably rotating said output shaft in one rotational direction, each driver means being effective for the rotation of said output shaft for a driving cycle of said output shaft, with continuously varying rates of rotational velocity having acceleration from dwell to maximum velocity and deceleration from maximum velocity to dwell, and further being effective only during one-half of each rotational cycle imparted to each of said driver means by said input shaft; e. means including first unidirectional clutch means inter-coupling said first driver means to said input and output shafts for initiating rotation of said output shaft and for continuing said rotation for a first motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said first driver means at the end of said first motion segment; f. means including second unidirectional clutch means for intermittently inter-coupling said second driver means to said input and output shafts in phased relationship to said first driver means and for achieving over-riding de-coUpling of said first driver means from said output shaft for continuing rotation of said output shaft for a second motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said second driver means upon completion of said second motion segment; g. means for maintaining said output shaft means in locked disposition while said first driver means and said second driver means are simultaneously de-coupled from said output shaft to impart a dwell cycle to said web; and said hot knife means comprising: h. heated blade means disposed generally transversely of the web axis and normally spaced from said web axis during advance of the web, and means for reciprocably moving said blade relative to said web to bring said blade into contact with said superimposed webs for welding said webs together during said period of dwell.

Claim 10

Thermoplastic web treating apparatus comprising, in combination, drive means for intermittently advancing superimposed webs of thermoplastic sheet film material and for stopping said superimposed webs for a pre-determined period of dwell, and hot knife means for thermally welding said superimposed webs together at predetermined spaced intervals therealong, said drive means comprising: a. drive means for imparting repeating cycles of intermittent motion and dwell to said web with the motion normally being along a certain pre-determined web direction, said drive means including output shaft means having first and second input driver means operatively coupled thereto; b. input shaft means and means for drivably rotating said input shaft in one rotational direction; c. unitary output shaft means adapted to be operatively coupled to said web for imparting motion thereto; d. first and second driver means arranged in phased relationship one-to-another and being responsive to the rotation of said input shaft means and operatively coupled to said output shaft for drivably rotating said output shaft in one rotational direction, each driver means being effective for the rotation of said output shaft for a driving cycle of said output shaft, with continuously varying rates of rotational velocity having acceleration from dwell to maximum velocity and deceleration from maximum velocity to dwell, and further being effective only during one-half of each rotational cycle imparted to each of said driver means by said input shaft; e. means including first unidirectional clutch means inter-coupling said first driver means to said input and output shafts for initiating rotation of said output shaft and for continuing said rotation for a first motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said first driver means at the end of said first motion segment; f. means including second unidirectional clutch means for intermittently inter-coupling said second driver means to said input and output shafts in phased relationship to said first driver means and for achieving over-riding de-coUpling of said first driver means from said output shaft for continuing rotation of said output shaft for a second motion segment not exceeding one-half cycle of rotation of said input shaft and for de-coupling said second driver means upon completion of said second motion segment; g. means for maintaining said output shaft means in locked disposition while said first driver means and said second driver means are simultaneously de-coupled from said output shaft to impart a dwell cycle to said web; and said hot knife means comprising: h. heated blade means disposed generally transversely of the web axis and normally spaced from said web axis during advance of the web, and means for reciprocably moving said blade relative to said web to bring said blade into contact with said superimposed webs for welding said webs together during said period of dwell.

Claim 11

The combination as defined in claim 8 being particularly characterized in that said hot knife means is adapted to move reciprocably toward and away from said superimposed webs, and into contact with said webs.