US 6,726,467 B1 · Injection molding nozzle

Abstract

Multi-cavity injection molding apparatus includes a plurality of injection nozzles, each of which has a two-piece tip assembly in the nature of a replaceable tip and a retainer that detachably secures the tip to the nozzle body. The retainers are constructed from material having a lower coefficient of thermal conductivity than the tips so that the retainers also serve to insulate the tips from the relatively cold, surrounding heat sink presented by the mold. Although each retainer prevents its tip from being unintentionally axially released from the nozzle body, the retainer engages the tip at only two axially spaced locations along its length so as to present an insulating air gap in surrounding relationship to much of the tip. The otherwise exposed end of the air gap is sealed off when the nozzle is hot by virtue of a sealing collar on the retainer that progressively tightens against the cooperating, beveled surface of the tip as the tip heats up. Each nozzle is mounted on the manifold block in a ball and socket relationship so that the nozzles can swivel and self-align as the manifold block and nozzles heat up from room temperature to operating temperature at the commencement of the injection process.

Claims21

Dependent claims

An injection molding nozzle for dispensing hot melt comprising:

an elongated, tubular nozzle body having an axially disposed socket in a discharge end thereof;
a generally cylindrical, hollow nozzle tip located within said socket and having an inboard base portion of one diameter and an outboard neck portion of a lesser diameter to present an outwardly facing shoulder at the intersection of the base portion and the neck portion;
and
a retainer detachably secured to the body and removably retaining the tip within said socket,
said retainer including a sleeve located within said socket in surrounding relation to said neck portion of the tip,
said sleeve having an inboard end that overlies and abuttingly engages the shoulder of the tip to prevent axial displacement of the tip from the socket,
said sleeve further having an axial, tip-receiving bore therethrough that has an enlarged inboard section circumscribing the neck portion of the tip in radially spaced relation thereto to define an insulating air gap that surrounds the neck portion of the tip,
said bore further including a constricted outboard section defining a collar on the retainer that circumscribes and substantially sealingly engages the neck portion of the tip when the nozzle is hot to prevent substantial entry of hot melt into the air gap from outside the nozzle.

5 more elements

Injection molding apparatus comprising:

a mold having a plurality of product cavity spaces, a corresponding number of nozzle-receiving wells for the cavity spaces, and a gate communicating each cavity space with a corresponding one of the wells;
and
distribution apparatus for injecting hot melt into the cavity spaces, said distribution apparatus comprising,
a manifold block having a plurality of concave swivel seats,
a corresponding plurality of discharge nozzles projecting into said wells for delivering hot melt to the cavity spaces through said gates,
each nozzle having a generally spherical swivel base matingly nested within a corresponding one of the seats, and
structure securing the nozzles to the block in a manner to permit the base of each nozzle to swivel within its seat,
each of said seats having a hot melt supply port and the base of each nozzle having a hot melt inlet communicating with said port in different swivelled positions of the nozzle,
each of said nozzles including an elongated nozzle body, a replaceable tip at a discharge end of the body remote from the base, and a retainer detachably secured to the body and removably retaining the tip on the body,
each of said retainers having an end face and a radially outermost, circular edge that is disposed radially outwardly beyond said body,
said tip projecting axially through and beyond said face and having a melt passage,
each well having an innermost, end surface through which the gate extends,
said end surface being disposed in spaced opposition to the face of the retainer to present a void between the end surface and the retainer face,
each well further having an axially extending sidewall circumscribing said edge of the retainer at the lateral extremity of said end surface to locate and maintain the melt passage of the tip in axial registration with the gate of the mold during swivelling of the nozzle,
each of said retainers being constructed of a lower thermally conductive material than the corresponding tip whereby to insulate the tip from the mold.

12 more elements

Dependencies are inferred from the claim text.

Injection molding nozzle

Life of this patent

Injection molding nozzle

Life of this patent

Abstract

Claims21