Carton flap sealing

Claim 2

A hollow member for applying heated air to heat-sealable surfaces of a pair of carton flaps folded to form an acute angle relative onE to the other, said hollow member comprising an elongate chamber connectable through a valve with a source of heated air, a nozzle extending lengthwise of and outwards from the chamber for location between the closure flaps, a closure member closing the end of the nozzle remote from the chamber, and opposed slots extending lengthwise of the nozzle and having a width selected to direct heated air on to predetermined mating areas of the closure flaps, one longitudinal side of each slot being defined by said closure member to deflect heated air from the nozzle and through the slots at substantially equal mass flow rates.

Claim 3

A hollow member according to claim 1, wherein the chamber is of linear cross-section and the nozzle extends outwards from a corner of the chamber.

Claim 4

A hollow member according to claim 2, wherein the chamber is of generally triangular cross-section.

Claim 5

A hollow member according to claim 1, in combination with a valve comprising a valve housing having an inlet tube connected with the elongate chamber, an exhaust tube opening from the housing, and a piston slidable in the valve housing and so constructed that in one position thereof the piston permits the passage of heated air into the inlet tube and obturates the exhaust tube and in a second position thereof the piston obturates the inlet tube and directs heated air into the exhaust tube.

Claim 6

The combination according to claim 4, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.

Claim 7

A hollow member according to claim 1 in combination with pusher elements carried by an endless conveyor, first folder elements located alongside the path of the conveyor and operable to fold a pair of carton flaps to the acute angle relationship, guide elements extending lengthwise of the path of the conveyor and operable to retain the pair of carton flaps in said angular relation thereof, said elongate chamber extending lengthwise of the path of the conveyor, said nozzle extending lengthwise of and into the path formed between a pair of closure flaps engaged by said guides, a valve housing connectable with a source of heated air and including an inlet tube connected to the elongate chamber, an exhaust tube opening from the housing, a piston slidable in the valve housing, piston-actuating means operable on starting and stopping of the conveyor respectively to move the piston to a position at which heated air can pass into the inlet tube and the exhaust tube is obturated and to a position at which heated air can pass into the exhaust tube and the inlet tube is obturated, and second folder elements operable to press the carton flaps into sealing relation one with the other.

Claim 8

The combination of claim 6, wherein the chamber is of linear cross-section and the nozzle extends outwards from a corner of the chamber.

Claim 9

The combination of claim 7, wherein the chamber is of generally triangular cross-section.

Claim 10

The combination of claim 6, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.

Claim 11

The combination of claim 8, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.