Apparatus for blow molding

Claim 2

Apparatus for molding, comprising a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the rod being provided with a radially-extending flange which closes the bore when the rod is in the said first position, and an air passage extending through the flange to supply the air passage in the rod with pressure air when the rod is in the second position, the rod being movable to a third position for stripping a formed article, a ring-like stripper being provided with an aperture through which the rod passes in moving from the second position to the third position, and the aperture in the stripper being large enough to allow the passage of the flange, but not a portion of the formed article.

Claim 3

Apparatus for molding as recited in claim 1, wherein an air passage extends through the rod to a free end, and wherein the said free end is located in the recess only when the rod is in the said second position.

Claim 4

Apparatus for molding as recited in claim 1, wherein the mold is formed in two separable parts with a secondary recess in each half separated axially from the first-mentioned recess, wherein the secondary recesses serve, when the mold is closed, to clamp around the flange, and wherein a passage extends through the mold into a secondary recess to communicate with the air passage in the flange.

Claim 5

Apparatus for molding as recited in claim 1, wherein the mold is formed in two separable parts, each part having a wall adjacent the extruder, the walls having mating knife edges that meet when the mold is closed, so that, when the rod has moved to the second position with the free end within the recess and spaced from the said walls, a tube of plastic overlies the rod, but a solid cylinder of plastic extends from the free end of the rod to the extruder and the closure of the mold causes the knife edges to cut through the said cylinder.

Claim 6

Apparatus for molding as recited in claim 1, wherein the said actuator is a fluid cylinder having A piston rod coaxial with and connected to the blow rod.

Claim 7

Apparatus for molding, comprising: a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the said bore being formed in a sleeve which is slidably mounted in a housing of the extruder, the said relative movement taking place by axial movement of the sleeve, and the movement of the sleeve being brought about by the engagement of a rotatable gear mounted in the housing engaging a rack formed on the exterior of the sleeve.

Claim 8

Apparatus for molding, comprising: a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the said bore being formed in a sleeve which is slidably mounted in a housing of the extruder, the said relative movement taking place by axial movement of the sleeve, and the movement of the sleeve being brought about by the engagement of a rotatable gear mounted in the housing engaging a rack formed on the exterior of the sleeve.

Claim 9

Apparatus for molding as recited in claim 6, wherein an air passage extends through the rod to a free end, and wherein the said free end is located in the recess only when the rod is in the said second position.

Claim 10

Apparatus for molding as recited in claim 6, wherein the rod is provided with a radially-extending flange which closes the bore when the rod is in the said first position, and wherein an air passage extends through the flange to supply the air passage in the rod with pressure air when the rod is in the second position.

Claim 11

Apparatus for molding as recited in claim 8, wherein the rod is movable to a third position for stripping a formed article, wherein a ring-like stripper is provided with an aperture through which the rod passes in moving from the second position to the third position, and wherein the aperture in the stripper is large enough to allow the passage of the flange, but not a portion of the formed article.

Claim 12

Apparatus for molding as recited in claim 8, wherein the mold is formed in two separable parts with a secondary recess in each half separated axially from the first-mentioned recess, wherein the secondary recesses serve, when the mold is closed, to clamp around the flange, and wherein a passage extends through the mold into a secondary recess to communicate with the air passage in the flange.

Claim 13

Apparatus for molding as recited in claim 6, wherein the mold is formed in two separable parts, each part having a wall adjacent the extruder, the walls having mating knife edges that meet when the mold is closed, so that, when the rod has moved to the second position with the free end within the recess and spaced from the said walls, a tube of plastic overlies the rod, but a solid cylinder of plastic extends from the free end of the rod to the extruder and the closure of the mold causes the knife edges to cut through the said cylinder.

Claim 14

Apparatus for molding as recited in claim 6, wherein the said actuator is a fluid cylinder having a piston rod coaxial with and connected to the blow rod.

Claim 15

Apparatus for molding as recited in claim 6, wherein the said bore is formed in a sleeve which is slidably mounted in a housing of the extruder, wherein the said relative movement takes place by axial movement of the sleeve, and wherein the movement of the sleeve is brought about by the engagement of a rotatable gear mounted in the housing engaging a rack formed on the exterior of the sleeve.

Claim 16

Apparatus for molding, comprising a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the rod being movable to a third position for stripping a formed article, a ring-like stripper being provided with an aperture through which the rod passes in moving from the second position to the third position, and the aperture in the stripper being large enough to allow the passage of the rod, but not a portion of the formed article.

Claim 17

Apparatus for molding, comprising a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the rod being movable to a third position for stripping a formed article, a ring-like stripper being provided with an aperture through which the rod passes in moving from the second position to the third position, and the aperture in the stripper being large enough to allow the passage of the rod, but not a portion of the formed article.

Claim 18

Apparatus for molding, comprising a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, and being movable between a closed and an open position, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the rod being provided with a radially-extending flange which closes the bore when the rod is in the said first position, and an air passage extending through the periphery of the flange to supply the air passage in the rod with pressure air when the rod is in the second position, and the mold having an air passage which mates with the air passage of the flange when the mold is in its closed position, to supply air to the air passage of the flange but the air passage in the mold is spaced from the air passage in the flange when the mold is in its open position.

Claim 19

Apparatus for molding, comprising a. an extruder having an outlet bore and a feed means, b. a mold having a cavity aligned with the bore, and being movable between a closed and an open position, c. a blow rod extending through the mold, and d. an actuator for bringing about relative movement between the rod and bore from a first position in which the rod lies in the bore to a second position in which the rod lies in the cavity, and e. means connecting the actuator and the feed means so that the latter is operated to press molten plastic through the bore at the same rate that the rod moves axially of the bore in moving from the first position to the second position, the rod being provided with a radially-extending flange which closes the bore when the rod is in the said first position, and an air passage extending through the periphery of the flange to supply the air passage in the rod with pressure air when the rod is in the second position, and the mold having an air passage which mates with the air passage of the flange when the mold is in its closed position, to supply air to the air passage of the flange but the air passage in the mold is spaced from the air passage in the flange when the mold is in its open position.