Molding of elongate plastic cylinders

Claim 5

A method as recited in claim 2 wherein said injecting step further includes the step of injecting plastic through a plurality of gates spaced uniformly around the linear portion of said clearance space.

Claim 6

A method as recited in claim 2 wherein said inserting step further comprises the step of forming said clearance space such that said linear flow portion separates all of said nonlinear flow portion from said female mold cavity entrance.

Claim 7

A method as recited in claim 3 wherein said inserting step further comprises the step of forming said clearance space such that said linear flow portion separates all of said nonlinear flow portion from said female mold cavity entrance.

Claim 8

Apparatus for molding in one piece an elongate cylindrical hollow body having walls of substantially uniform thickness, requiring a linear and a nonlinear flow of plastic material to mold the cylindrical body, comprising a female mold structure providing a cavity that is shaped to define the exterior of said body, and extending inwardly from an entrance, a male mold member insertable into the cavity through said entrance and providing a clearance space of substantially uniform thickness between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and a portion for said linear plastic flow, and means disposed intermediate the ends of said linear flow portion for injecting plastic material into said linear flow portion in an area adjacent said nonlinear flow portion of the clearance space to fill the clearance space, said injecting means supplying plastic into said clearance space in one direction towards the female mold cavity entrance and in a generally opposite direction to said nonlinear flow portion without causing substantial deflection of the male mold member.

Claim 9

Apparatus for molding in one piece an elongate cylindrical hollow body having walls of substantially uniform thickness, requiring a linear and a nonlinear flow of plastic material to mold the cylindrical body, comprising a female mold structure providing a cavity that is shaped to define the exterior of said body, and extending inwardly from an entrance, a male mold member insertable into the cavity through said entrance and providing a clearance space of substantially uniform thickness between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and a portion for said linear plastic flow, and means disposed intermediate the ends of said linear flow portion for injecting plastic material into said linear flow portion in an area adjacent said nonlinear flow portion of the clearance space to fill the clearance space, said injecting means supplying plastic into said clearance space in one direction towards the female mold cavity entrance and in a generally opposite direction to said nonlinear flow portion without causing substantial deflection of the male mold member.

Claim 10

An apparatus as recited in claim 6, wherein said injecting means comprises a plurality of gates in the female mold structure spaced uniformly around the female mold cavity.

Claim 11

An apparatus as recited in claim 7, wherein all of said nonlinear flow portion is separated from said female mold cavity entrance by said linear flow portion.

Claim 12

Apparatus as claimed in claim 7, wherein said nonlinear flow portion comprises an end wall forming portion for the cylindrical body and communicating with a nozzle forming portion extending inwardly of the female mold structure from said end wall forming portion.

Claim 13

Apparatus as claimed in claim 9, wherein said gates lead into the cavity in a cylindrical portion thereof, around the male mold member near said end wall forming portion.

Claim 14

Apparatus as claimed in claim 10, wherein the female mold structure comprises a first mold member defining said cylindrical portion and containing the gates, and a second mold member defining the nonlinear flow portion, the first and second mold members defining between them a runner manifold for supplying plastic to the gates.

Claim 15

Apparatus as claimed in claim 11, wherein the first and second mold members are separable, the second mold member having pins which, when the first and second mold members are not separated, have heads protruding into the manifold to be embedded in plastic therein, the heads when the first and second mold members are separated, after molding, drawing with them waste plastic from the manifold and from the gates.

Claim 16

Apparatus as claimed in claim 12, including means for pulling the pins out of the waste plastic to discard the latter.

Claim 17

Apparatus as claimed in claim 13, including means for retracting the male mold member from the cavity and for stripping from the male mold member the molded elongate body.

Claim 18

Apparatus for molding in one piece an elongate cylindrical hollow body requiring a nonlinear flow of plastic material at one end of the cylindrical body, comprising female mold structure providing a cavity that is shaped to define the exterior of said body, the cavity extending inwardly from an entrance, a male mold member insertable into the entrance and providing a clearance space between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and means for injecting plastic material into the cavity at a location along a cylindrical portion of said clearance space and adjacent and nonlinear flow portion of the clearance space such that, upon entering the clearance space, some of the plastic material flows in a first direction lengthwise of said cylindrical body towards said entrance and the remainder of the material flow in a different direction towards said nonlinear flow portion.

Claim 19

Apparatus for molding in one piece an elongate cylindrical hollow body requiring a nonlinear flow of plastic material at one end of the cylindrical body, comprising female mold structure providing a cavity that is shaped to define the exterior of said body, the cavity extending inwardly from an entrance, a male mold member insertable into the entrance and providing a clearance space between the male mold member and the female mold structure to define said body, said clearance space including a portion for said nonlinear plastic flow remote from said entrance, and means for injecting plastic material into the cavity at a location along a cylindrical portion of said clearance space and adjacent and nonlinear flow portion of the clearance space such that, upon entering the clearance space, some of the plastic material flows in a first direction lengthwise of said cylindrical body towards said entrance and the remainder of the material flow in a different direction towards said nonlinear flow portion.

Claim 20

The apparatus of claim 15 wherein said different direction is substantially opposite to said first direction.