MXPA99007411A - Nozzle assembly for injection molding apparatus - Google Patents

Abstract

A nozzle assembly (10) for use with injection molding apparatus includes an outer sleeve (12) having a relatively large bore extending from an open rearward end forwardly to a substantially closed forward end, and having an injection orifice (22) therein. An inner nozzle tip (14) is located within the sleeve (12), and has a radial flange and an internal bore extending from a rearward opened end to a forward tip having a plurality of flow orifices upstream of the injection orifice. A manifold insert (18) is located within the outer sleeve (12) and includes a through bore in axial alignment with the bore of the nozzle tip (14). The manifold insert (18) has a forward end which receives the nozzle tip (14) and abuts the radial flange. A coil heater (16) is located radially between the manifold and the outer sleeve, a forward end of the coil heater (16) is seated on the radial flange. The manifold insert (18), nozzle tip (14), and coil heater (16) form a subassembly which is easily removed and reinserted vis-a-vis the outer sleeve.

Description

This invention relates to a nozzle assembly, replacement, for an injection molding machine.

L: 'BACKGROUND OF THE INVENTION In a typical injection molding process, the plastic resin is fed to a rotating screw found in a hot cylinder, where the plastic melts and mixes. The resulting hot plastic is then injected at high pressure into a mold having one or more cavities that define the shape of the desired part. After the injection, the mold is cooled to solidify the plastic. Subsequently, the mold is opened and the formed parts are ejected, '-. . ''. . : • During the injection process, the molten resin is injected into a network of channels for fiow, which are generally referred to as a gutter system. The Mnti ne "system controls and controls the temperature of the melt through the use of ditch heaters, distributor heaters and nozzle heaters.Nozzle assemblies often incorporate cartridge heaters, and in some cases , these heaters have been subject to faults that have been difficult to find and repair.A second problem with existing nozzle assemblies is the time required to replace a failed heater unit, in other words, it does not matter if A cartridge-type heater or spiral type heater is used, some nozzle designs require that certain components be first removed from the weld.After replacement, those same components must be cleaned and replaced in place by welding. necessary to implement this procedure is unacceptably excessive.

DESCRIPTION OF THE INVENTION The present invention provides a replacement nozzle assembly that eliminates the need for a cartridge heater and reduces the time required to replace a damaged heater located within the nozzle assembly. More specifically, the nozzle assembly includes an outer sleeve, an inner nozzle, a spiral heater and an internal T-tube distributor, through which the molten material flows into the nozzle. The inner nozzle tip is threaded to the front end of the T stem and the spiral heater is received above the T-rod distributor, between a front radial flange that is over the inner nozzle and a radial stop head , rear, which is on the T-rod distributor. This subassembly, comprising the distributor, tip of the nozzle and spiral heater, is received by sliding inside the outer sleeve, and a screw fastener is inserted between the radial rear projection of the T-rod distributor and the outer sleeve. With this arrangement there is no need to weld the components of the assembly and then desolder them to effect the installation and / or removal of the components. In contrast, the distributor is easily removed from the outer sleeve, along with the nozzle tip and the spiral heater, by simply removing the screw holder and sliding the distributor (with the nozzle tip and the spiral heater) out of the sleeve. Thus, in accordance with an exemplary embodiment of the invention, there is provided a nozzle assembly for use with an injection molding apparatus, comprising an outer sleeve having a relatively large hole extending from an open rear end, towards in front and to a substantially closed front end having therein an injection hole; an inner nozzle tip having a radial projection, the nozzle tip has a hole extending from a rear open end to a front tip having a plurality of flow holes located upstream of the injection port; a distributor insert located inside the outer sleeve and including a through hole that is in axial alignment with the nozzle tip hole, the distributor insert has a front end that receives the tip of the nozzle and splices with the radial projection; and a spiral heater located radially between the distributor insert and the outer sleeve, a front end of the spiral heater seated in the radial projection. According to another aspect, the invention provides a nozzle assembly for an injection molding apparatus, the nozzle assembly has an outer sleeve, a front end of which has a hole formed, and a rear end of which is substantially open; and a subassembly can be received by sliding inside the outer sleeve, the subassembly includes a distributor insert for molten material, a nozzle tip, secured so that it can be removed, the distributor at a front end thereof, and a heater spiral contained above the distributor and coupled by a projection that is on the nozzle tip; the dispenser has a stop head which is at a rear end thereof and which is adapted for fixing to the outer sleeve and for withdrawal thereof. Other objects and advantages of the invention will become apparent from the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a cross section through a nozzle assembly for injection molding, in accordance with the invention; Figures 2, 3 and 4 are individual cross sections of the different components included in Figure 1; Figure 4A is an elevation view of the front end of the nozzle tip; Y Figure 5 is a side cross-sectional view, with part separation, of the nozzle assembly shown in Figure 1.

THE BEST WAY TO CARRY OUT THE INVENTION With particular reference to FIGS. 1 and 5, the injection molding nozzle assembly 10, in accordance with an exemplary embodiment of the invention, includes an outer sleeve 12 generally cylindrical, an inner nozzle tip 14, a spiral heater 16 and a T-rod distributor insert, 18. The T-rod distributor insert, 18, has an internal bore 20 through which the molten material is supplied to the inner nozzle tip 14, and from which it is supplied. the material to a chamber that lies between the inner nozzle 14 and the sleeve 12. The latter has formed a single hole 22 from which the material is ejected into a mold, in an injection molding process. Focusing now on Figure 2, the sleeve 12 has an internal bore 24 extending axially from the open rear end 26 of the sleeve, forward and up to the bore 22. At the front end of the sleeve, the bore 24 is reduced, from stepwise, through the annular flanges 26, 28, to a portion of smaller diameter 30 which, in turn, leads to a conical wall 32 ending at its tip with the orifice 22. The outer surface of the sleeve is in cylindrical general, with a tapered front end 34 and a diametrically enlarged portion 36, which extends above approximately the rear half of the sleeve. For a purpose that is explained later, a threaded hole 38 is formed in the rear face of the sleeve. With reference to Figure 3, the internal T-stem distributor insert 18 has a body formed at its rear end. 40, elongate, and a radial stop head, 42. The distributor insert 18 has an internal passage hole, 44, extending from an enlarged inlet portion 46, forward and to a reamed portion 48, threaded, at the front end of it. In the stop head 42 a fastening hole 50 is provided, which can be aligned with the hole 38 that is located at the rear end of the sleeve 12. The threaded front portion 50 is adapted to receive, by screwing, the inner nozzle tip 14, which is best seen in Figure 4. The nozzle tip 14 is screwed onto an outer surface 52 located behind a radial shoulder 54. A pointed end 56 is located ahead of the nose 54. A hole 58 extends from the rear end, forwardly and to a plurality (four, as shown) of holes 60 arranged in a circle about the front tip 62. With reference to Figure 5, it can be seen that the nozzle tip 14 is threadedly secured to the front threaded end 48 of the T-rod dispenser insert, 18, with one side of the radial projection 54 seated on the flange 28, and the outer side engaged with the hub. to the front of the T-rod distributor insert, 18, and with the hole 58 axially aligned with the hole 44. The fully seated engagement of the radial shoulder 54 on the sleeve flange, prevents any amount of molten material from entering the sleeve. Radial space lying between the sleeve 12 and the distributor insert 18 and exhausting through the slot 66 (described later). The spiral heater 16 can be received above the body 40 of the rod and has an axial length substantially equal to the body 40 of the rod. A conductive portion 64 of the heater 16 extends radially outwardly for connection to a conductive wire or the like. The T-spindle distributor insert, 18, the inner nozzle tip 14 and the spiral heater 16 are then received by sliding inside the sleeve 12, and the spiral heater 16 occupies most of the radial space between the T-rod distributor, 18, and the inner surface of the outer sleeve 12. The conductor 64 of the spiral heater 64 is contained in a radial groove or recess 66 formed in the rear face of the sleeve 12. In the assembled condition shown in Figure 1, the radial front projection 54 of the inner nozzle tip 14 is seated on the radial flange 28 of the sleeve 12 and the front end of the inner nozzle is contained in the tapered front end of the sleeve, thus creating an annular chamber 68. The latter receives the molten plastic through of the holes 60, and the plastic is then ejected from the chamber through the single hole 22. Note that the tip 62 of the inner nozzle 14 is located closely to the Lying to the orifice 22. When the component parts are assembled as described, a threaded screw holder 70 is employed to secure the T-rod distributor insert, 18, to the sleeve 12, through the aligned holes 38 and 50. With In the above arrangement it will be appreciated that if the spiral heater 16 is damaged, its replacement is easily accomplished by simply removing the fastener 70 and the subassembly including the T-18 spout, the interior nozzle tip 14 and the spiral heater. 16. In other words, since the spiral heater splices with the radially outermost portion of the radial projection 54 on the tip of the inner nozzle 14, the spiral heater 16 is removed with the distributor 18 and the nozzle tip 14 Note that the open slot 66 makes it possible for the heater to be removed from the sleeve. Then, the inner nozzle tip 14 can be unscrewed from the T-rod distributor 18, and the spiral heater can be removed from the body 40 of the distributor. The replacement and reassembly is carried out with a simple inversion of the steps mentioned above. It will also be appreciated that with the construction described hereinabove there are no welding and desoldering parts during the assembly / disassembly process. According to the preferred embodiment, the sleeve 12 and the T-rod distributor insert 18 can be made of stainless steel, while the mouthpiece tip 14 is made of beryllium copper. The spiral heater 16 may be of any suitable design, for example, a spiral heater for 240 volts, manufactured by RAMA Corp., and available through Plástic Process Equipment Inc. Although the invention has been described in relation to what it is presently considered as the most practical and preferred embodiment, it should be understood that the invention will not be limited to the described modality, but on the contrary, it is intended to cover several modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (11)

NOVELTY OF THE INVENTION Having described the foregoing invention, it is considered as a novelty, and therefore, the content of the following is claimed as property: CLAIMS

1. A nozzle assembly for use with an injection molding apparatus characterized in that it comprises an outer sleeve having a relatively large hole extending from a forwardly open rear end and to a substantially closed front end having an orifice therein of injection; an inner nozzle tip having a radial projection, the nozzle tip having a hole extending from an open rear end to a front tip having a plurality of flow orifices located upstream of the injection port; a distributor insert located inside the outer sleeve and including a through hole that is in axial alignment with the nozzle tip hole, the distributor insert has a front end that receives the tip of the nozzle and which splices with the radial projection; and a spiral heater located radially between the distributor insert and the outer sleeve, a front end of the spiral heater is seated on the radial projection,

2. The nozzle according to claim 1, characterized in that the distributor insert has a radial stop head formed at a rear end thereof, the stop head, radial, spliced with the rear end of the outer sleeve, and also because at least one The clamp extends through the radial stop head of the insert into the outer sleeve so that the distributor insert, nozzle tip and spiral heater can be removed from the outer sleeve.

3. The nozzle according to claim 1, characterized in that a rear end of the spiral heater splices with the radial stop head.

4. The nozzle according to claim 1, characterized in that the nozzle tip includes a cylindrical portion extending rearwardly of the radial projection, the cylindrical portion being contained within the forward end of the dispenser insert.

5. The nozzle according to claim 1, characterized in that the outer sleeve has an annular front edge formed on which the radial projection of the inner nozzle tip rests.

6. The nozzle according to claim 1, characterized in that it includes a chamber formed between the inner nozzle tip and the outer nozzle, in front of the radial projection.

7. The nozzle according to claim 1, characterized in that the spiral heater includes a conductor extending substantially radially outwardly from an open slot in the sleeve, and the slot is closed by the stop head. .

8. A nozzle assembly for an injection molding apparatus, and the nozzle assembly is characterized in that it has an outer sleeve, a leading end of which has an orifice formed, and a trailing end of which is substantially open; and a sub-pack that can be contained by sliding inside the outer sleeve, the subassembly includes a distributor insert for molten material, a nozzle tip, secured, so that it can be removed, the distributor at a front end thereof and a heater coiled above the distributor and coupled by a projection on the nozzle tip; the dispenser has a stop head at a rear end thereof, adapted to be attached, so that it can be removed, to the outer sleeve.

9. The nozzle according to claim 8, characterized in that the outer sleeve has a front annular rim formed on which the radial projection of the inner nozzle tip rests.

10. The nozzle according to claim 8, characterized in that it includes a chamber formed between the inner nozzle tip and the outer nozzle, in front of the radial projection.

11. The nozzle according to claim 8, characterized in that the spiral heater includes a conductor extending, substantially radially outwardly of an open slot in the sleeve, and the slot is closed by the stop head . SUMMARY OF THE INVENTION A nozzle assembly (10) for use with an injection molding apparatus, including an outer sleeve (12) having a relatively large hole extending from an open rear end, forward and to a substantially closed front end , and having in it an injection hole (22). Inside the sleeve (12) an inner nozzle tip (14) is located, and has a radial projection and an internal bore extending from an open rear end to a front tip having a plurality of flow openings that meet upstream of the injection hole. A distributor insert (18) is located inside the outer sleeve (12) and includes a through hole that is in axial alignment with the mouth of the mouthpiece tip (14). The distributor insert (18) has a front end which contains the nozzle tip (14) and which splices with the radial projection. A spiral heater (16) is located radially between the distributor and the outer sleeve, and a front end of the spiral heater (16) is seated on the radial projection. The distributor insert (18), the nozzle tip (14), and the spiral heater (16) form a secondary sub-assembly that is easily removed and reinserted, face to face, with respect to the outer sleeve. The most representative figure of the invention is number 1.