Hot air sealing apparatus

Claim 2

In a machine for closing and sealing the end closure flaps of a carton which flaps have a heat activatable adhesive on the surface thereof which is to be sealed, a hot air applying nozzle having a surface with perforations permitting passage of the hot air, said nozzle disposed with the perForated surface in position for directing hot air onto the adhesive bearing surface of a closure flap, means connected to the nozzle for supplying hot air to the nozzle which hot air suplying means comprises an exterior tank forming cylinder having an opening forming an air intake at one end, an inner cylinder of small diameter and shorter length mounted in said exterior cylinder with the side walls spaced from the side walls of the exterior cylinder and with one end closed and spaced from the air intake end of said exterior cylinder so as to permit air to enter said intake opening and pass down between the walls of said cylinders, the other end of said inner cylinder being open and engaging with an end wall of said exterior cylinder, a discharge opening in said end wall of said exterior cylinder which forms a passageway for connecting the interior of said inner cylinder with said nozzle, heating elements in said inner cylinder for heating air passing through said inner cylinder, and an intermediate cylinder having its side walls interposed between the spaced side walls of said exterior and said inner cylinders and having the side walls at one end terminating short of the end wall of said exterior cylinder and closed at the other end with an opening forming an air passageway into the closed end of said inner cylinder so as to connect the interior of said intermediate cylinder with the interior of said inner cylinder, and a bypass means for controlling the flow of hot air from said inner cylinder to said nozzle which bypass means comprises a valve body mounted on the end of said inner cylinder and having an opening into the nozzle which is aligned with the opening in the bottom end of said inner cylinder and a valve member incorporated in said valve body which is swingably mounted to block the flow of air through said opening into the nozzle while simultaneously opening a port for diverting hot air from said tank into the atmosphere.

Claim 3

In a machine as set forth in claim 1 wherein said heating elements comprise a plurality of elongate rod-like electrical resistance elements mounted in an end plate and extending into said inner cylinder.

Claim 4

In a machine as set forth in claim 1 wherein said bypass valve has a body forming housing with openings in oppositely disposed walls forming a normally open passageway for flow of hot air from said inner cylinder into said nozzle, an exhaust port located in a wall of said housing adjoining the opening into said nozzle, a baffle plate in said housing and a hinged plate forming a closing gate member which is located so as to swing between a position to co-operate with said baffle plate in closing the passageway to the nozzle and a position to close said exhaust port and means controlling the swinging movement of said gate member.

Claim 5

In a machine as set forth in claim 1 wherein said bypass valve comprises a valve body forming the bottom end wall of said tank forming cylinder and having a pair of parallel bores therein forming air passageways one of which connects said inner cylinder with said nozzle and the other of which forms an air passageway connecting said outer cylinder with an exhaust port and means operative to close one of said passageways while simultaneously opening the other one of said passageways.

Claim 6

In a machine for closing and sealing the end closure flaps of a carton which flaps have a heat activatable adhesive on the surface thereof which is to be sealed, a hot air applying nozzle having a surface with perforations permitting passage of the hot air, said nozzle disposed with the perforated surface in position for directing hot air onto the adhesive bearing surface of a closure flap, means connected to the nozzle for supplying hot air to the nozzle which hot air supplying means comprises an exterior tank forming cylinder having an opening forming an air intake at one end, an inner cylinder of small diameter and shorter length mounted in said exterior cylinder with the side walls spaced from the side walls of the exterior cylinder and with one end closed and spaced from the air intake end of said exterior cylinder so as to permit air to enter said intake opening and pass down between the walls of said cylinders, the other end of said inner cylinder being open and engaging with an end wall of said exterior cylinder, a discharge opening in said end wall of said exterior cylinder which forms a passageway for connecting the interior of said inner cylinder with said nozzle, heating elements in said inner cylinder for heating air passing through said inner cylinder, and an intermediate cylinder having its side walls interposed between the spaced side walls of said exterior and said inner cylinders and having the side walls at one end terminating short of the end wall of said exterior cylinder and closed at the other end with an opening forming an air passageway into the closed end of said inner cylinder so as to connect the interior of said intermediate cylinder with the interior of said inner cylinder and a bypass means for controlling the flow of hot air between the hot air supplying means and the nozzle which bypass means is located adjacent the nozzle and includes a valve body mounted at the hot air discharge end with a pair of air passageways extending therethrough, one of which connects with the interior of said inner cylinder and the other of which connects with an opening in said exterior cylinder and valve gate members operable in said air passageways in said valve body to open one of said passageways while closing the other one of said passageways for interrupting the flow of hot air to the nozzle and simultaneously diverting the hot air to a port for exhausting the hot air to the atmosphere.

Claim 7

In a machine for closing and sealing the end closure flaps of a carton which flaps have a heat activatable adhesive on the surface thereof which is to be sealed, a hot air applying nozzle having a surface with perforations permitting passage of the hot air, said nozzle disposed with the perforated surface in position for directing hot air onto the adhesive bearing surface of a closure flap, means connected to the nozzle for supplying hot air to the nozzle which hot air supplying means comprises an exterior tank forming cylinder having an opening forming an air intake at one end, an inner cylinder of small diameter and shorter length mounted in said exterior cylinder with the side walls spaced from the side walls of the exterior cylinder and with one end closed and spaced from the air intake end of said exterior cylinder so as to permit air to enter said intake opening and pass down between the walls of said cylinders, the other end of said inner cylinder being open and engaging with an end wall of said exterior cylinder, a discharge opening in said end wall of said exterior cylinder which forms a passageway for connecting the interior of said inner cylinder with said nozzle, heating elements in said inner cylinder for heating air passing through said inner cylinder, and an intermediate cylinder having its side walls interposed between the spaced side walls of said exterior and said inner cylinders and having the side walls at one end terminating short of the end wall of said exterior cylinder and closed at the other end with an opening forming an air passageway into the closed end of said inner cylinder so as to connect the interior of said intermediate cylinder with the interior of said inner cylinder and a bypass means for controlling the flow of hot air between the hot air supplying means and the nozzle which bypass means is located adjacent the nozzle and includes a valve body mounted at the hot air discharge end with a pair of air passageways extending therethrough, one of which connects with the interior of said inner cylinder and the other of which connects with an opening in said exterior cylinder and valve gate members operable in said air passageways in said valve body to open one of said passageways while closing the other one of said passageways for interrupting the flow of hot air to the nozzle and simultaneously diverting the hot air to a port for exhausting the hot air to the atmosphere.