Edge gate hotrunner apparatus

Abstract

An edge gate hotrunner apparatus comprising: a nozzle body comprising an upstream portion and a downstream portion, the downstream portion comprising a plurality of lobes each independently displaceable, the lobes and the upstream portion forming an integral body, the nozzle body defining a network of channels for conveying a molten material; a plurality of tip assemblies, each tip assembly in fluid communication with a respective lobe; and a cone shaped member received in a space partially defined by the lobes, such that displacing the cone shaped member upstream within the space urges the lobes in a direction away from the cone shaped member.

Description

EDGE GATE HOTRUNNER APPARATUSFIELD

[0001] The invention relates generally to a hotrunner apparatus, and in particular, to an edge gate hotrunner apparatus.BACKGROUND

[0002] Edge gate hotrunner apparatuses, in injection molding, injects molten material into a cavity having a gate that is not inline with the main channel of the nozzle body. Edge gating presents challenges such as misalignment between the tip and the mold cavity structure.BRIEF SUMMARY

[0003] An aspect of the present application provides an edge gate hotrunner apparatus comprising: a nozzle body comprising an upstream portion and a downstream portion, the downstream portion comprising a plurality of lobes each independently displaceable, the lobes and the upstream portion forming an integral body, the nozzle body defining a network of channels for conveying a molten material, the network of channels comprising an upstream branch and a plurality of downstream branches, each of the downstream branches partially defined by a respective lobe; a plurality of tip assemblies, each tip assembly in fluid communication with a respective lobe; and a cone shaped member received in a space defined by the lobes, such that displacing the cone shaped member upstream within the space urges the lobes in a direction away from the cone shaped member.

[0004] The nozzle body can be cylindrically shaped having a central axis, displacing the cone shaped member upstream within the space urges the lobes in a direction away from the central axis.

[0005] The cone shaped member can be frustum cone shaped defining a bore coaxial with the nozzle body, the edge gate hotrunner apparatus can further comprise a fastenerpassing through the bore and threadably connected with the nozzle body securing the cone shaped member to the nozzle body.

[0006] A downstream portion of the space can be cone shaped.

[0007] The network of channels can comprise an upstream branch and a plurality of downstream branches, the upstream branch defined by the upstream portion of the nozzle body and each of the downstream branches partially defined by a respective lobe.

[0008] Each tip assembly can comprise a tip and a washer, the washer received in a respective lobe and located between the tip and the lobe, the tip defining a channel in fluid communication with the downstream branch of the network of channels.

[0009] The cone shaped member can comprise an external curved surface and each lobe can comprise an internal curved surface complementary to the external curved surface of the cone shaped member.

[0010] The space can define an opening at a downstream end and a threaded portion at an upstream end, and the downstream portion of the space tapers from the opening upstream towards the threaded portion.

[0011] A washer of at least one of the tip assemblies can be a male leveling washer having a rounded face seated in a rounded surface of a pocket in the respective lobe.

[0012] Each tip assembly can further comprise a bushing for receiving the respective tip and coupling the tip to a mold cavity structure, the bushing can comprise an annular ridge on an external surface of the bushing to form a diameter seal with a surface of the mold cavity structure.

[0013] The edge gate hotrunner apparatus can comprise two lobes created by an incision creating a gap between the adjacent lobes.

[0014] The edge gate hotrunner apparatus can comprise four lobes created by two intersecting cuts in the bottom portion of the nozzle body, the cuts creating a gap between the angularly adjacent lobes.BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings are not to scale.

[0016] FIG. 1 is a sectional view of a hotrunner apparatus according to an embodiment of the present application;

[0017] FIG. 2 is a sectional view of the hotrunner apparatus of FIG. 1 with the cone shaped member displaced further upstream than the condition shown in FIG. 1;

[0018] FIG. 3 is a bottom perspective exploded view of some members of the hotrunner apparatus of FIG. 1 with a portion of the nozzle body cut out to illustrate internal features; and

[0019] FIG. 4 is a top perspective exploded view of the tip assembly and the mold cavity structure of FIG. 1.DETAILED DESCRIPTION

[0020] Specific embodiments of the present application are now described with reference to the figures. The following detailed description is merely exemplary in nature and is not intended to limit the concepts and uses of the concepts. Furthermore, there is no intention to be restricted by any expressed or implied theory in the present application. In the description, “downstream” is used with reference to the direction of the molten material flow from an injector to a mold, and also with reference to the order of components, or features thereof, through which the molten material flows from the injector to the mold, whereas “upstream” is used with reference to the opposite direction. Depending on context, upstream and downstream can be used as relative or absolute terms.

[0021] In the current application, a particular reference numeral are used to refer to like elements singularly or plurally. For example, tip assemblies 20 are singularly referenced as tip assembly 20 and plurally as tip assemblies 20.

[0022] Referring to FIG. 1, a hotrunner apparatus for injecting a molten material (e.g., plastic) (not shown) is generally indicated by 10; hotrunner apparatus 10 is an edge gatehotrunner apparatus. Hotrunner apparatus 10 comprises a nozzle 12 and a plurality of tip assemblies 20. Nozzle 12 comprises a nozzle flange 13 and a nozzle body 15. In the illustrated embodiments, nozzle body 15 is cylindrically shaped having a central axis A. Nozzle body 15 comprises an upstream portion 25 and a downstream portion 30. Downstream portion 30 comprises a plurality of lobes 35 each independently displaceable. Lobes 35 and upstream portion 25 form an integral body. Each tip assembly 20 is in fluid communication with a respective lobe 35. Nozzle body 15 defines a network of channels 40 for conveying a molten material (not shown). Network of channels 40 comprises an upstream branch 45 and a plurality of downstream branches 50. Each of downstream branches 50 is partially defined by a respective lobe 35. (In the illustrated embodiments, four lobes 35 are shown but a person of ordinary skill in the art would appreciate that depending on the application, any number of lobes 35 greater than one can be implemented.) Downstream branches 50 diverge from upstream branch 45 at a junction 52. Downstream branch 50 comprises an upstream segment 53 and a downstream segment 54. Each downstream segment 54 is defined by a respective lobe 35.

[0023] Referring to FIG. 2, hotrunner apparatus 10 comprises a cone shaped member 55 received in a space 60 defined by lobes 35. In the illustrated embodiments, cone shaped member 55 is a frustum cone shaped structure defining a bore 65 coaxial with nozzle body 15. Space 60 comprises a cone shaped portion 70 downstream of a threaded portion 75. Hotrunner apparatus 10 comprises a fastener 80 for insertion through bore 65 to threadably connect with nozzle body 15 securing cone shaped member 55 to nozzle body 15. (In the illustrated embodiments, fastener 80 is a shoulder bolt but a person of ordinary skill in the art would appreciate that other suitable fasteners can be implemented.) Fastener 80 comprises a threaded end portion 85 to mate with threaded portion 75 of space 60 when fastener 80 is installed in nozzle body 15. Each lobe 35 comprises a downstream end 88 (see FIG. 3). Displacing cone shaped member 55 upstream in the direction X within space 60 urges at least downstream end 88 of lobes 35 away, in direction Y, from central axis A.

[0024] Referring to FIG. 4, each tip assembly 20 comprises a washer 90, a tip 95, and a bushing 100. Washer 90 is received in a respective lobe 35 and located between tip 95 and lobe 35. Tip 95 defines a channel 105 that is in fluid communication with downstream branch 50 of network of channels 40. Bushing 100 defines a bore 110 to receive tip 95. Bushing 100 is for coupling tip 95 to a mold cavity structure 115. Mold cavity structure 115 defines a cavity 117 (see FIG. 1) for receiving a molten material to mold an article (not shown). Bushing 100 comprises an annular ridge 120 on an external surface 125 of bushing 100 to form a diameter seal 130 (see FIG. 2) with a surface 135 of a bore of 137 of mold cavity structure 115. Bushing 100 is partially received in bore 137.

[0025] Referring to FIG. 3, lobes 35 are created by making incisions (from downstream end 139 of nozzle body 15) into nozzle body 15 resulting in gaps 140 separating angularly adjacent lobes 35. Each lobe 35 comprises an internal surface 141 curved to complement an external curved surface 142 of cone shaped member 55. Cone shaped portion 70 is tapered from opening 143 upstream towards threaded portion 75. As cone shaped member 55 is displaced upstream (i.e., in direction X), the complementary surfaces 141, 142 engage each other to evenly distribute the radial force applied by cone shaped member 55 onto lobes 35 and by extension onto tip assemblies 20. Using a cone shaped member and a complementary cone shaped space as a wedging mechanism may stably bias lobes 35 against mold cavity structure 115 which may reduce the risks of misalignment between tip assemblies 20 with mold cavity structure 115. Hotrunner apparatus 10 comprises a washer 144 and heater 145. Depending on application, washer 144 may be optional. Heater 145 heats nozzle body 15 to keep the molten material in network of channels 40 at an operational temperature. Tip assemblies 20 draws heat from nozzle body 15 via conduction between washers 90 and tip 95 (see FIG. 1).

[0026] Each lobe 35 defines a pocket 150 to receive a washer 90. In some embodiments, washer 90 is a flat washer 155 and pocket 150 is a flat pocket 160 (see FIG. 1) configured to receive flat washer 155. Flat washer 155 comprises a planar face 165 for engaging a complementary planar face 170 of flat pocket 160. In some embodiments, washer 90 is a male leveling washer 175 and pocket 150 is a rounded pocket 180 configured to receive male leveling washer 175. An upstream portion 182 ofrounded pocket is shaped as a female leveling washer to receive male leveling washer 175. Male leveling washer 175 comprises a rounded face 185 for engaging a complementary rounded face 190 of rounded pocket 180 (see FIG. 1). Male levelling washer 175 is seated in rounded pocket 180.

[0027] FIG. 2 shows a state with fastener 80 and cone shaped member 55 further upstream in direction X than that in FIG. 1. FIG. 2 shows lobes 35 in a condition after at least downstream end 88 of lobes 35 has been displaced further (than the condition shown in FIG. 1) in direction Y by cone shaped member 55. With fastener 80 tightened to a suitable threshold urging lobes 35 in direction Y, lobes 35 may in turn urge tip assemblies 20 against mold cavity structure 115 forming a seal between washer 90 and pocket 150, between washer 90 and tip 95, and between tip 95 and bushing 100. With lobes 35 moving away from cone shaped member 55, lobes 35 may tilt by angle Z (in a counterclockwise direction), which may in turn cause tips 95 to tilt by angle Z (in a counterclockwise direction) causing a misalignment between tip 95 and a gate 195 of mold cavity structure 115. Depending on the application, using male leveling washer 175 may alleviate tilting of tip 95.

[0028] While various embodiments according to the present application have been described above, it should be understood that they have been presented by way of illustration and example only, and not limitation. It will be apparent to persons of relevant ordinary skill in the relevant art that various changes in form and detail can be made therein without departing from the scope of the present application. It will also be understood that each feature of each embodiment discussed herein, may be used in combination with the features of any other embodiment. Thus, the breadth and scope of the present invention should not be limited by the above-described exemplary embodiments, but should be defined only in accordance with the appended claims and their equivalents.

Claims

CLAIMSWhat is claimed is:

1. An edge gate hotrunner apparatus comprising: a nozzle body comprising an upstream portion and a downstream portion, the downstream portion comprising a plurality of lobes each independently displaceable, the lobes and the upstream portion forming an integral body, the nozzle body defining a network of channels for conveying a molten material, the network of channels comprising an upstream branch and a plurality of downstream branches, each of the downstream branches partially defined by a respective lobe; a plurality of tip assemblies, each tip assembly in fluid communication with a respective lobe; and a cone shaped member received in a space defined by the lobes, such that displacing the cone shaped member upstream within the space urges the lobes in a direction away from the cone shaped member.

2. The edge gate hotrunner apparatus of claim 1, wherein the nozzle body is cylindrically shaped having a central axis, displacing the cone shaped member upstream within the space urges the lobes in a direction away from the central axis.

3. The edge gate hotrunner apparatus of claim 2, wherein the cone shaped member is frustum cone shaped defining a bore coaxial with the nozzle body, the edge gate hotrunner apparatus further comprises a fastener passing through the bore and threadably connected with the nozzle body securing the cone shaped member to the nozzle body.

4. The edge gate hotrunner apparatus of claim 3, wherein a downstream portion of the space is cone shaped.

5. The edge gate hotrunner apparatus of claim 4, wherein the network of channels comprises a upstream branch and a plurality of downstream branches, the upstreambranch defined by the upstream portion of the nozzle body and each of the downstream branches partially defined by a respective lobe.

6. The edge gate hotrunner apparatus of claim 5, wherein each tip assembly comprises a tip and a washer, the washer received in a respective lobe and located between the tip and the lobe, the tip defining a channel in fluid communication with the downstream branch of the network of channels.

7. The edge gate hotrunner apparatus of claim 6, wherein the cone shaped member comprises an external curved surface and each lobe comprises an internal curved surface complementary to the external curved surface of the cone shaped member.

8. The edge gate hotrunner apparatus of claim 7, wherein the space defines an opening at a downstream end and a threaded portion at an upstream end, and the downstream portion of the space tapers from the opening upstream towards the threaded portion.

9. The edge gate hotrunner apparatus of claim 8, wherein a washer of at least one of the tip assemblies is a male leveling washer having a rounded face seated in a rounded surface of a pocket in the respective lobe.

10. The edge gate hotrunner apparatus of claim 9, wherein each tip assembly further comprises a bushing for receiving the respective tip and coupling the tip to a mold cavity structure, the bushing comprising an annular ridge on an external surface of the bushing to form a diameter seal with a surface of the mold cavity structure.1 l.The edge gate hotrunner apparatus of claim 10, comprising two lobes created by an incision creating a gap between the adjacent lobes.

12. The edge gate hotrunner apparatus of claim 10, comprising four lobes created by two intersecting cuts in the bottom portion of the nozzle body, the cuts creating a gap between the angularly adjacent lobes.

13. The edge gate hotrunner apparatus of claim 6, comprising two lobes created by a cut creating a gap between the adjacent lobes.

14. The edge gate hotrunner apparatus of claim 7, comprising four lobes created by two intersecting cuts in the bottom portion of the nozzle body, the cuts creating a gap between the angularly adjacent lobes.

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