Blow molding machines

Claim 2

In a blow molding machine for the production of hollow bodies of thermoplastic material by the extrusion-blow process, of the type including blow mold halves arranged inside a chase between form plates of the chase, and a horizontal transport drive for moving the chase with the blow mold and form plates between a receiving position, aligned with an extrusion nozzle, and a blowing position, in which the blow mold halves are offset downwardly and laterally relative to the receiving position: the improvement comprising, in combination, vertical guides on said form plates; respective guide plates having said blow mold halves secured thereto, said guide plates being engaged with said guides for vertical displacement of said blow mold halves relative to said form plates and said vertical guides; and lifting mechanism acting between said form plates and said guide plates to effect such relative vertical displacement of only said guide plates and said blow mold halves with said form plates and said vertical guides of said chase remaining fixed in elevation.

Claim 3

In a blow molding machine for the production of hollow bodies of thermoplastic material by the extrusion-blow process, of the type including blow mold halves arranged inside a chase between form plates of the chase, and a horizontal transport drive for moving the chase with the blow mold halves and form plates between a receiving position, aligned with an extrusion nozzle, and a blowing position, in which the blow mold halves are offset downwardly and laterally relative to the receiving position: the improviment comprising, in combination, vertical guides on said form plates; respective guide plates having said blow mold halves secured thereto, said guide plates being engaged with said guides for vertical displacement of said blow mold halves relative to said form plates and said vertical guides; lifting mechanism acting between said form plates and said guide plates to effect such relative vertical displacement of only said guide plates and said blow mold halves with said form plates and said vertical guides of said chase remaining fixed in elevation; said lifting mechanism comprising racks each secured on a respective guide plate to extend vertically thereof; a shaft rotatably mounted in said chase to extend through said form plates; gears keyed to said shaft to rotate therewith, and each engaged with a respective rack, said gears being displaceable axially relative to said shaft; and means operable, responsive to movement of said chase to said receiving position aligned with an extrusion nozzle, by said transport drive, to rotate said shaft to lift said blow mold halves to an upper limiting position.

Claim 4

In a blow molding machine for the production of hollow bodies of thermoplastic material by the extrusion-blow process, of the type including blow mold halves arranged inside a chase between form plates of the chase, and a horizontal transport drive for moving the chase with the blow mold halves and form plates between a receiving position, aligned with an extrusion nozzle, and a blowing position, in which the blow mold halves are offset downwardly and laterally relative to the receiving position: the improviment comprising, in combination, vertical guides on said form plates; respective guide plates having said blow mold halves secured thereto, said guide plates being engaged with said guides for vertical displacement of said blow mold halves relative to said form plates and said vertical guides; lifting mechanism acting between said form plates and said guide plates to effect such relative vertical displacement of only said guide plates and said blow mold halves with said form plates and said vertical guides of said chase remaining fixed in elevation; said lifting mechanism comprising racks each secured on a respective guide plate to extend vertically thereof; a shaft rotatably mounted in said chase to extend through said form plates; gears keyed to said shaft to rotate therewith, and each engaged with a respective rack, said gears being displaceable axially relative to said shaft; and means operable, responsive to movement of said chase to said receiving position aligned with an extrusion nozzle, by said transport drive, to rotate said shaft to lift said blow mold halves to an upper limiting position.

Claim 5

In a blow molding machine, the improvement claimed in claim 2, in which said gears are formed on respective bearings rotatably mounted in respective form plates and secured against axial displacement relative to the associated form plates.

Claim 6

In a blow molding machine, the improvement claimed in claim 2, including a horizontally extending guide track supporting said chase for movement between said receiving and blowing positions; a drive gear secured to said shaft externally of said chase; and a stationary drive rack arranged alongside said guide track and extending parallel thereto in advance of the end of said guide track in the zone of said receiving position aligned with an extrusion nozzle; said drive gear, responsive to movement of said chase toward said receiving position by said horizontal transport drive, engaging and meshing with said rack to rotate said shaft to lift said blow mold halves to said upper limiting position; said drive rack having a length corresponding to the vertical lift height of said blow mold halves from a lower position to said upper position.

Claim 7

In a blow molding machine, the improvement claimed in claim 4, including stop means on each guide plate engageable with the associated form plate to limit downward movement of said blow mold halves responsive to disengagement of said drive gear from said drive rack as said chase is moved toward said blowing position by said transport drive.

Claim 8

In a blow molding machine for the production of hollow bodies of thermoplastic material by the extrusion-blow process, of the type including blow mold halves arranged inside a chase between form plates of the chase, and a horizontal transport drive for moving the chase with the blow mold halves and form plates between a receiving position, aligned with an extrusion nozzle, and a blowing position, in which the blow mold halves are offset downwardly and laTerally relative to the receiving position: the improvement comprising, in combination, vertical guides on said form plates; respective guide plates having said blow mold halves secured thereto, said guide plates being engaged with said guides for vertical displacement of said blow mold halves relative to said form plates and said vertical guides; lifting mechanism acting between said form plates and said guide plates to effect such relative vertical displacement of only said guide plates and said blow mold halves with said form plates and said vertical guides of said chase remaining fixed in elevation; said lifting mechanism comprising racks each secured to a respective guide plate to extend vertically thereof; a pair of gears, each operatively engaged with a respective rack; a shaft rotatably mounted to extend through said form plates; means securing one end of said shaft to one form plate against relative axial displacement; one of said gears being fixed to rotate with said shaft adjacent said one form plate; the other of said gears being keyed to rotate with said shaft while being axially displaceable relative to said shaft; said shaft being axially displaceable relative to the other form plate and to said chase; a pivot lever secured to the opposite end of said shaft for rotation with said shaft and axial displacement with said shaft; a stop fixedly positioned on the frame of said blow molding machine in the zone of said receiving position; said pivot lever being movable into and out of operative relation with said stop responsive to axial displacement of said shaft; said pivot lever being displaced into the plane of said stop responsive to opening of said blow mold halves so that, upon movement of said chase toward said extrusion nozzle by said transport drive, said pivot lever will engage said stop to rotate said shaft to lift said blow mold halves.

Claim 9

In a blow molding machine for the production of hollow bodies of thermoplastic material by the extrusion-blow process, of the type including blow mold halves arranged inside a chase between form plates of the chase, and a horizontal transport drive for moving the chase with the blow mold halves and form plates between a receiving position, aligned with an extrusion nozzle, and a blowing position, in which the blow mold halves are offset downwardly and laTerally relative to the receiving position: the improvement comprising, in combination, vertical guides on said form plates; respective guide plates having said blow mold halves secured thereto, said guide plates being engaged with said guides for vertical displacement of said blow mold halves relative to said form plates and said vertical guides; lifting mechanism acting between said form plates and said guide plates to effect such relative vertical displacement of only said guide plates and said blow mold halves with said form plates and said vertical guides of said chase remaining fixed in elevation; said lifting mechanism comprising racks each secured to a respective guide plate to extend vertically thereof; a pair of gears, each operatively engaged with a respective rack; a shaft rotatably mounted to extend through said form plates; means securing one end of said shaft to one form plate against relative axial displacement; one of said gears being fixed to rotate with said shaft adjacent said one form plate; the other of said gears being keyed to rotate with said shaft while being axially displaceable relative to said shaft; said shaft being axially displaceable relative to the other form plate and to said chase; a pivot lever secured to the opposite end of said shaft for rotation with said shaft and axial displacement with said shaft; a stop fixedly positioned on the frame of said blow molding machine in the zone of said receiving position; said pivot lever being movable into and out of operative relation with said stop responsive to axial displacement of said shaft; said pivot lever being displaced into the plane of said stop responsive to opening of said blow mold halves so that, upon movement of said chase toward said extrusion nozzle by said transport drive, said pivot lever will engage said stop to rotate said shaft to lift said blow mold halves.

Claim 10

In a blow molding machine, the improvement claimed in claim 6, in which said pivot lever is moved out of the plane of said stop when said chase is aligned with said extrusion nozzle and responsive to closing of said blow mold halves; resetting means operable to pivot said pivot lever to a position effecting lowering of said blow mold halves; and means operable, responsive to closing of said blow mold halves, to activate said resetting means.

Claim 11

In a blow molding machine, the improvement claimed in claim 7, in which said resetting means comprises a pneumatic cylinder-piston actuator connected to said pivot lever; said means operable responsive to closing of said blow mold halves comprising a limit switch actuated responsive to closing of said blow mold halves; and control means controlling the supply of air to said actuator and controlled by said limit switch.

Claim 12

In a blow molding machine, the improvement claimed in claim 8, including a toggle lever mechanism connected to said shaft and in operative connection with said blow mold halves; said shaft being axially displaceable by actuation of said toggle lever mechanism and said toggle lever mechanism, in its expanded position, closing said blow mold halves; and a piston-cylinder actuator having a piston rod connected to said toggle lever mechanism and operable to expand and contract the latter, said actuator being arranged centrally of said toggle lever mechanism.