Method of and apparatus for automatically controlling transfer of filmstrips

Claim 3

A method according to claim 1, including the step of, following such interrupting of the feeding of all of the strips, individually braking said one strip while feeding the other strips; and responsive to lateral realignment of the detected register mark on said one strip with the corresponding register marks on the other strip, releasing the braking of said one strip for conjoint feeding of said one strip with the other strips.

Claim 4

A method according to claim 1, in which, during each intermittent feeding stroke, the strips are advanced through a distance corresponding to the longitudinal spacing of longitudinally adjacent register marks thereon; and, between the intermittent feeding strokes of each strip, performing the bag formation thereon.

Claim 5

A method according to claim 3, in which the bag formation on each strip is effected by a heat sealing operation between successive intermittent feeding strokes.

Claim 6

Apparatus for controlling feeding of transversely spaced film strip, each consisting of a longitudinally folded film or a collapsed tube of a thermoplastic synthetic resin, in a bag-making machine to form bags, while maintaining lateral alignment between corresponding uniformly longitudinally spaced register marks on the strips, said apparatus comprising, in combination, conveyor means, including a pair of pinch rolls adapted to grip said strips and feed the same therethroUgh in transversely spaced parallel relation with each other; driving means operable to rotate said pinch, rolls intermittently to effect intermittent conjoint feeding of all the strips; respective scanning means operable to scan each strip, during feeding thereof, to detect the respective register marks; a first braking device operatively connected to said scanning means and selectively operable to brake said conveyor means responsive to detection by said scanning means, of a register mark on one strip in advance of detection of the corresponding register mark on the other strips, to interrupt the feeding of all the strips; respective second braking devices each operatively associated with a respective strip and selectively operable individually to brake the associated strip; means operatively connecting said second braking devices to said scanning means and operable, responsive to detection of a register mark on one strip in advance of detection of the corresponding register marks on the other strips, to actuate only that second braking device associated with said one strip to brake said one strip during the next feeding stroke of said conveyor means conjointly feeding all the other strips; and means connected to said scanning means and to said second braking devices operable, responsive to lateral realignment of the detected register mark on said one strip with the corresponding register marks on the other strips, to deactivate said second braking device associated with said one strip for feeding of said one strip conjointly with the other strips.

Claim 7

Apparatus for controlling feeding of transversely spaced film strip, each consisting of a longitudinally folded film or a collapsed tube of a thermoplastic synthetic resin, in a bag-making machine to form bags, while maintaining lateral alignment between corresponding uniformly longitudinally spaced register marks on the strips, said apparatus comprising, in combination, conveyor means, including a pair of pinch rolls adapted to grip said strips and feed the same therethroUgh in transversely spaced parallel relation with each other; driving means operable to rotate said pinch, rolls intermittently to effect intermittent conjoint feeding of all the strips; respective scanning means operable to scan each strip, during feeding thereof, to detect the respective register marks; a first braking device operatively connected to said scanning means and selectively operable to brake said conveyor means responsive to detection by said scanning means, of a register mark on one strip in advance of detection of the corresponding register mark on the other strips, to interrupt the feeding of all the strips; respective second braking devices each operatively associated with a respective strip and selectively operable individually to brake the associated strip; means operatively connecting said second braking devices to said scanning means and operable, responsive to detection of a register mark on one strip in advance of detection of the corresponding register marks on the other strips, to actuate only that second braking device associated with said one strip to brake said one strip during the next feeding stroke of said conveyor means conjointly feeding all the other strips; and means connected to said scanning means and to said second braking devices operable, responsive to lateral realignment of the detected register mark on said one strip with the corresponding register marks on the other strips, to deactivate said second braking device associated with said one strip for feeding of said one strip conjointly with the other strips.

Claim 8

Apparatus according to claim 5, in which said first braking device is an electromagnetic clutch-brake assembly including an electromagnetic clutch and an electromagnetic brake connected to be alternately operable.

Claim 9

Apparatus according to claim 6, in which each second braking device comprises an electromagnetic release means, a return spring and a roller supporting the associated strip; each return spring pressing the associated strip against the surface of said roller, to brake the associated strip, responsive to deenergization of the associated electromagnetic means.

Claim 10

Apparatus according to claim 5, in which said driving means includes a drive shaft; a driven shaft connected to at least one of said pinch rollers; crank means connecting said drive shaft to said driven shaft for oscillation of said driven shaft responsive to rotation of said drive shaft; and a unidirectional clutch device interposed between said crank means and said conveyor means and operable to rotate said driven shaft intermittently in only one direction responsive to rotation of said drive shaft.

Claim 11

Apparatus according to claim 8, in which said first braking device comprises an electromagnetic clutch-brake assembly including an electromagnetic clutch and an electromagnetic brake which are operable in alternation; switch means connected to said electromagnetic clutch-brake assembly and operable to effect such alternate actuation of said electromagnetic clutch and said electromagnetic brake; and cam means on said drive shaft operating said switch means to energize said electromagnetic clutch during a portion of each revolution of said drive shaft and to de-energize said electromagnetic clutch and to energize said electromagnetic brake during the remainder of each revolution of said drive shaft.

Claim 12

Apparatus according to claim 9, in which said scanning means comprises respective photoelectric detectors operatively associated with each strip in advance of said conveyor means.

Claim 13

Apparatus according to claim 10, including heat-sealing means operatively associated with said strips in advance of said conveyor means and operable to heat-seal said strips between the intermittent feeding strokes of said conveyor means.