Machine for folding plastic bags

Claim 2

A bag folding machine comprising a frame, a plurality of continuous belts, mounting means for mounting said belts for movement along said frame, drive means for driving said belts longitudinally of said frame, bag-engaging means for engaging the leading edge of a bag supported on and being moved by said belts, actuating means for moving said bag-engaging means from a first position adjacent said belts to engage said bag to a second position lifting said leading edge above said belts while the portion of said bag remote from said bag-engaging means advances with said belts to form a fold in said bag, and sensing means sensing the proximity of said leading edge to energize said actuating means.

Claim 3

A bag folding machine according to claim 1 which further comprises a pair of rollers rotatable in said frame transverse to and at the level of the upper stretch of said belts positioned to grip said fold as said bag advances on said belts to crease said bag at said fold and feed said bag off said belts and out of engagement with said bag-engaging means.

Claim 4

A machine according to claim 2 which further comprises second bag-engaging means on the side of said rollers opposite said first-mentioned bag-engaging means, said second bag-engaging means arranged to engage the leading edge of a bag folded by said rollers and supported on and being moved by said belts, second actuating means for moving said second bag-engaging means from a first position adjacent said belts to engage said folded bag to a second position lifting said leading edge of said folded bag above said belts, sensing means sensing the proximity of said leading edge of said folded bag to energize said second actuating means, and a second pair of rollers positioned to grip a folded portion of said folded bag and feed said folded bag off said belts and out of engagement with said second bag-engaging means.

Claim 5

A machine according to claim 2 which further comprises a second frame transverse to and at the discharge end of said first-mentioned frame having a table mounted thereon, said table positioned to support folded bags discharged from said rollers, said table formed with a longitudinal gap, second bag-engaging means mounted for movement between a first position immediately below said gap to engage a folded bag on said table and a second position below said table, a plurality of continuous second belts mounted in said second frame for movement transverse to said first-mentioned belts and located at an elevation above said second position, second actuating means for moving said second belt engaging means between said second belts between first and second positions and second sensing means sensing the position of a folded bag on said table to energize said second actuating means to move said second bag-engaging means to grip a folded bag on said table, pull said folded bag Through said gap, thereby forming a transverse fold in said folded bag and deposit said transversely folded bag on said second belts for movement away from said table.

Claim 6

A machine according to claim 2 which further comprises stripper means associated with at least one of said rollers to guide said bag through said rollers without wrapping around either of said rollers.

Claim 7

A machine according to claim 1 in which said bag-engaging means comprises a plurality of sucker tubes each connected to a source of vacuum, each said tube having its exposed end terminating at said belts when said actuating means is in first position.

Claim 8

A machine according to claim 6 in which said tubes are mounted for movement about an axis transverse to and above the level of said belts, said belts being spaced from each other in gaps, said tubes in said gaps, said tubes in first position slightly below, and in second position above, said belts and moving from first to second position in an arc having said axis as its center in the same direction as the direction of movement of the upper stretches of said belts.

Claim 9

A machine according to claim 1 in which said actuating means comprises a shaft transverse to said belts, said bag-engaging means mounted eccentric to said shaft, and means for oscillating said shaft.

Claim 10

A machine according to claim 1 in which said actuating means, said bag-engaging means and said sensing means are movable along said frame to adjust for bags of different lengths.

Claim 11

A machine according to claim 1 in which said sensing means comprises an electric eye sensitive to presence of said bag on said belt approaching said eye.