Screws

Full Title

Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor > Component parts, details or accessories; Auxiliary operations > Means for plasticising or homogenising the moulding material or forcing it through the nozzle or die > Details of extruders > Screws

Classification Context

Section:

PERFORMING OPERATIONS; TRANSPORTING

Class:

WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL

Subclass:

SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING

Child Classifications

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• B29C 48/51 with internal flow passages, e.g. for molten material
• B29C 48/52 with an outer diameter varying along the longitudinal axis, e.g. for obtaining different thread clearance
• B29C 48/53 having a varying channel depth, e.g. varying the diameter of the longitudinal screw trunk
• B29C 48/535 with thread pitch varying along the longitudinal axis
• B29C 48/54 with additional forward-feeding elements
• B29C 48/55 having reverse-feeding elements
• B29C 48/56 having grooves or cavities other than the thread or the channel
• B29C 48/565 having projections other than the thread, e.g. pins
• B29C 48/57 provided with kneading disc-like elements, e.g. with oval-shaped elements
• B29C 48/575 provided with elements of a generally circular cross-section for shearing the melt, i.e. shear-ring elements
• B29C 48/58 provided with seal ring elements, i.e. elements of generally circular and tapered shape for preventing the back flow of the melt
• B29C 48/585 provided with gears interacting with the flow
• B29C 48/59 characterised by details of the thread, i.e. the shape of a single thread of the material-feeding screw
• B29C 48/62 characterised by the shape of the thread channel, e.g. U-shaped
• B29C 48/625 characterised by the ratio of the threaded length of the screw to its outside diameter [L/D ratio]
• B29C 48/63 having sections without mixing elements or threads, i.e. having cylinder shaped sections
• B29C 48/635 Eccentrically rotating screws; Screws revolving around an axis other than their central axis
• B29C 48/64 Screws with two or more threads
• B29C 48/67 having incorporated mixing devices not provided for in groups