IE51116B1

IE51116B1 - Continuous moulding method and apparatus

Info

Publication number: IE51116B1
Application number: IE1072/81A
Authority: IE
Original assignee: Textron Inc
Priority date: 1980-05-30
Filing date: 1981-05-13
Publication date: 1986-10-01
Also published as: IE811072L; AU538672B2; JPS5772757A; AU7052681A; FR2483309A1; ES8300044A1; ES502194A0; BR8102964A; IT8121132A0; KR840000424B1; BE889014A; GB2076729B; DE3119035A1; KR830005936A; MX154888A; ZA812430B; AR229677A1; FR2483309B1; CA1154922A; GB2076729A

Abstract

In injection moulding articles continuously, the moulding cavities are formed by registering cavity portions in the periphery of a wheel (30) and rotating inner and outer continuous bands (32, 34) of successively greater circumferences, which bands encircle the wheel, these all being rotated and being pressed together over an angle of rotation.

Description

The present invention relates to methods and apparatus for continuous moulding, particularly such methods and apparatus employing continuously rotating cavity wheels and bands having mould cavities in them.

Known moulding methods and apparatus were limited to producing rather simple shapes since the mould cavities were formed by two mating mould portions only, and could not form articles with cavities or other complex shapes.

According to the invention, a method of continuously moulding articles comprises rotating a cavity wheel having a row of first cavity-defining portions extending around the wheel periphery; rotating an inner continuous band which encircles the wheel and which has in it second cavity-defining portions; rotating an outer continuous band which has third cavity-defining portions and which encircles the inner band and the cavity wheel; continuously bringing together portions of the inner and outer bands and the periphery of the cavity wheel as they rotate so that their cavity portions register and form mould cavities and maintain the cavity portions in register as the parts rotate through an angle of engagement; injecting hardenable material into the mould cavities; and hardening the hardenable material in the mould cavities to form the articles.

The invention also includes apparatus for carrying out the foregoing method comprising a cavity wheel having around its periphery a row of first cavitydefining portions, an inner continuous rotatable band encircling the cavity wheel and having a circumference larger than the periphery of the cavity wheel, an outer continuous rotatable band encircling the inner band and the cavity wheel and having a circumference larger than the circumference of the inner band, means for holding the inner and outer bands and the periphery of the cavity wheel together in engagement through an angle of engagement through which the bands and cavity wheel rotate, the inner and outer bands having second and third cavitydefining portions respectively, which with said first cavity-defining portions form moulding cavities for the articles in the angle of engagement, and means for 51110 injecting hardenable material into the so formed moulding cavities to harden in the cavities.

The invention enablesproduction of complex shapes, e.g. having in them slots or cavities, and/or facilitates expeditious removal of articles from a cavity wheel.

One advantage of the invention is that the forming of moulding cavities by first cavity-defining portions on a cavity wheel and at least second and third cavity-defining portions on respective inner and outer continuous bands enables the forming of cavities with core-like portions to mould complex or hollow shapes.

Another advantage of the invention is that an inner band or bands can provide improved stripping of moulded articles from a cavity wheel.

Other objects, advantages and features of the invention will be apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings, in which:Fig. 1 is a diagrammatical plan view of a moulding apparatus in accordance with the invention, Fig. 2 is a section view taken at line 2-2 in Fig. 1 and enlarged from Fig. 1, Fig. 3 is a further enlarged sectional view of a broken-away portion from the structure shown in Fig. 2, Fig. 4 is a perspective view of a brokenaway portion of the moulding apparatus of Fig. 1, - 3 51116 Fig. 5 is a plan view of a portion of a cavity wheel of Figs. 1-4, Fig. 6 is a plan view of a portion of an outer band of Figs. 1-4, Fig. 7 is a cross-sectional view of a portion of a second form of the moulding apparatus of the invention, Fig. 8 is a plan view of a segment of the cavity wheel and inner band of the apparatus of Fig. 7, Fig. 9 is a view similar to Fig. 7 of a third form of the moulding apparatus of the invention, Fig. 10 is a plan view of a segment of the cavity wheel and a pair of inner bands as in Fig. 9, Fig. 11 is a cross-sectional view showing 15 a fourth form of moulding apparatus of the invention, Fig. 12 is a view similar to Fig. 11 of another form of moulding apparatus of the invention.

Fig. 13 is a view similar to Figs. 11 and 12 of a fifth form of the moulding apparatus, Fig. 14 is a plan view of a segment of the cavity wheel and the pair of stripping bands of Fig. 13 and showing a moulded article, Fig. 15 is a view similar to Fig. of a seventh form of moulding apparatus, Fig. 16 is a plan view of Fig. 15, and Fig. 17 is a sectional view of a 5 portion of a modification of the apparatus of Fig. 2.

In Fig. 1, the forms of apparatus of the invention shown includes a cavity wheel 30, an inner band 32 encircling the cavity wheel 30, an outer band 34 encircling the inner band 32 and the cavity wheel 30, and an injection mechanism indicated generally at 36 and including a shoe 38 which with a roller 40 forces the outer band 34 and inner band 32 against the cavity wheel 30 over a selected angle of engagement 41. The cavity wheel 30 and bands 32 and 34 arc continuously rotated in the came direction past the injection mechanism 36 and the roller 40 so that within the angle of engagement 41 the bands 32 and 3Z and the cavity wheel 30 are brought together and continuously held in engagement. The cavity wheel 30 and the bands 32 and 34, where engaged together in the angle of engagement 41, form moulding cavities for receiving moulding material which is hardened therein to continuously form articles.

The moulding apparatus shown in Figs. 1-6 is particularly designed for moulding slide fastener elements 42 and 44 on respective inner edges of carrier tapes 46 and 48, the variation of Figs. 7 and 8 is designed to mould retainers for slide fasteners, the variation of Figs. 9 and 10 is designed to mould sliders for slide fasteners, the variation of Fig. 11 is designed tomould bolts, the variation of Fig. 12 is designed to mould nails, the variation of Figs. 13 and 14 is designed tomould parts 542 e.g. snap elements, and the variation of Figs. 15-16 is designed to mould pulls 642 for sliders of a slide fastener. Many other variation.·· can be devised for moulding various other articles.

In the apparatus of Figs. 1-6 for moulding co'ipl’iv elements 42 and 44 on inner edges of slide fastener t··;'and 48, the cavity wheel 30 includes an outer annular p-tibf. 50 suitably mounted on inner wheel members 52, 54 end 56. ·· pair of continuous spaced rows of cavity portions 60 and 62 are formed in the central outer peripheral portion of the member 50 for defining lover portions of the respective coupling elements 42 and 44. Annular channels 64 and 66 arcformed in the periphery in the wheel member 50 and have inner portions intersecting the outer portions of the cavities 60 and 62; such outer portions of the cavities 60 and 62 corresponding to body and heel portions of the elements 42 and 44. The channels 64 and 66 are designed to receive the tapes 46 and 48. An annular channel 68 is formed in the center of the periphery of the wheel 30 for receiving the band 32. Outer portions of the channel 68 intersect inner portions of the respective cavities 60 and 62 which correspond to the top portions of heads of the coupling elements 42 and 44. A pair of continuous spaced rows of cavity portions 70 and 72 are formed in central portions of the inner surface of the band 34. The band 32 has opposite edge portions which, during the angle of engagement 31, extend between inner portions of respective pairs of aligned cavity portions 60, 70 and 62, 72 to form core elements for themoulding apparatus to define grcv~s in the heads of the respective coupling elements 42 ar.fi :·!. The recesses or cavities 60 and 62 contain tonque-foi <'rg cavity portions 96 for forming tongues on the coupling elements 42 and 44 for engaging the grooves in the heads of opposite mating coupling elements. Openings 74 to the outside of the band 34 are formed between each pair of adjacent cavities 70 and 72 and have gate portions 76 ,-r.d 70 communicating with inner portions of the cavities 70 and 72.

For maintaining registration and alignment cf tha band 34 relative to the wheel 30, an outward extending annular flange 80 is formed on one side edge of the cuter periphery of the member 50, and an annular ring member 82 is mounted in a groove on the opposite edge of the '’heel 30. The flange 00 has an outer beveled surface 84 and an inner surface 86 extending perpendicular to the axis of rotation of the wheel 86 for engaging and positioning the one edge of the band 34 in a direction parallel to the axis of rotation. The ring member 82 has a series of rounded teeth or undulations 88 on the outer surface thereof for engaging mating teeth or undulations 90 formed by machining the inner surface of the other edge of band 34 to maintain angular positioning of the band 34 relative to the wheel 30. Inner edges of the teeth 88 engage inside edges of the band 34 bordering the teeth or undulations 90 cut in the band 34 to hold the band 34 in a direction parallel to the axis of rotation.

In a modification shown in Fig. 17, the flange 80, Fig. 2, is replaced by an annular ring member 92 substantially identical to the ring member 82 and mounted in a groove in an edge of the wheel. The member 92 has a series of rounded teeth (not shown) mating with teeth (not shown) on the band 34 with inner edges of the member teeth engaging inside edges of the band in a manner substantially a mirror image of the member 82, teeth 88 and teeth 90 of Fig. 2.

As shown in Fig. 3 it is noted that, in the angle of engagement 41, the upper surface of the tapes 46 and 48 and band 32 form a common cylindrical surface section with the outer surface of the peripheral member 50.

In operation of the apparatus of Figs. 1-6 and practice of the method of making slide fastener coupling elements, the cavity wheel 30, inner band 32 and outer band 34 are continuously rotated. Tapes 46 and 48 are fed into the channels 64 and 66 of the cavity wheel 30 at a point - 8 51116' prior to the engagement angle and where the bands 32 and 34 are separated from each other and the cavity wheel 30. As the wheel 30 and bands 32 and 34 are rotated, the shoe 38 engaging the band 34 forces the bands 34 and 32 into engagement together with the shoe 30. The roller 40 insures that the bands 32 and 34 remain in engagement throughout the angle of engagement 41. The band 34 is maintained in registration with the cavity wheel 50 by engagement of the teeth or undulations 90 with the teeth or undulations 08 formed on the outer edge of the cavity wheel. Flange 00 as well as the ring 82 engage the band 34 to maintain its positioning in a direction parallel to the axis of rotation. The cavities GO and cavities 70 together with the left fqc (as viewed in Figs. 2-4) of the inner band 32 form cavities for moulding the coupling elements 42 rhi Jo the cavities 62 and 72 together with the right edge of t!r. 'nrer band 32 form cavities for moulding the coupling elenienic 44 on the inner edge of the tape 48. Molten thermoplastic or other moulding material is injected by the injection mechanism 36 through the openings 74 and gates 71 and 70 into the respective cavities as the cavities pass the moulding mechanism 30. Subsequently the injected moulding material is hardened as engaging portions of the cavity wheel 30 and bands 32 and 34 continue to rotate through the angle of engagement 41; for example, molten thermoplastic is cooled and solidified by contact with the cavity wheel 30 and bands 32 and 34. 1 1 1 li After the coupling elements are hardened, the cavity wheel 30 and the bands 32 and 34 rotate past the roller 40, and the bands 32 and 34 separate from the moulding wheel. The coupling elements 42 and 44 are broken apart and pulled from the band 32. Because the band 32 engages into the head portions of the coupling elements, the separation of the band 32 from the cavity wheel 30 and the outer band 34 also removes the coupling elements 42 and 44 from the cavities 60 and 62 of the cavity wheel and the cavities 70 and 72 of the band 34.

The employment of rotating cavity wheels, inner and outer bands to form cavities for moulding articles permits continuous moulding of complicated shapes by utilizing inner band members as core members for making complex shapes.

Xn the variation of Figs. 7 and 8, a cavity wheel 130, inner band 132 and outer band 134 have portions which, when engaged together, form a moulding cavity to form a retainer for a slide fastener. Lower portions 160 of the cavities are formed in a continuous row in the outer periphery of the cavity wheel which contains a channel 168 for receiving the inner band 132. Upper portions 170 of the moulding cavities are formed on the inside of the band 134 while openings 174 extend through the band 134 to the upper surface thereof for providing a passage formoulding material. The inner band 132 has projections 140 which extend into central portions of the cavities formed by the cavity portions 160 and 170 so as to form core members extending into the cavities. The cavity wheel 130 is provided with registration teeth 188 mating with registration teeth 190 of the outer band 134 to maintain registration of the outer band 134 with the cavity wheel 130. Similarly, the inner band 132 is provided with registration teeth 192 which engage registration teeth 194 on the cavity wheel 130 to maintain the registration of the inner band 132 relative to the outer band 134 and cavity wheel 130. In operation of the variation of Figs. 7 and 8, retainers are continuously formed in the cavities defined by the cavity wheel 130 and bands 132 and 134 in the angle of engagement by injecting and hardening moulding material in the cavities. After separation of the bands 132 and 134 from each other and the cavity wheel 130, the retainers are removed from the projections 140.

The variation of Figs. 9 and 10 includes a cavity wheel 230, a pair of inner bands 232 and 233 and an outer band 234 which have respective portions for forming moulding cavities to form sliders for a slide fastener. The cavity wheel 230 has a continuous row of cavity portions 260 designed to form the lower portions of the sliders and has an annular channel 268 for receiving the pair of inner bands 232 and 233. Cavity portions 270 are formed in the inner surfaces of the band to form upper portions of the sliders. The cavity portions 270 communicate with input injection passages 274 which open in the upper surface of the band 234. The band 232 has core projections 240 while the band 233 has core projections 242 and 244 which cooperate with the core projection 240 to form the interior of the slider leaving an opening 245 to form the post of the slider. Grooves 246, 248, 250 and 254 in the respective bands 232 and 234 are designed to form the flanges on the sliders for engaging the heels of the coupling elements. Engaging teeth 288 and 290 on the respective cavity wheel 230 and band 234 provide for registration of the band 23 4 relative to the cavity wheel 230. Teeth 292 and 296 on the respective bands 232 and 239 mate with teeth 2n4 and 293 formed in the cavity wheel 230 to maintain regie1-ation of the bands 232 and 233 relative to the cavity -.-1)^-1 2-30 ·ηύ the outer band 234. In operation of th? variation of 'hr Figs. 9 and 10, the inner bands are separated afterdisengaging the cavity wheel 230 to permit removal of th? sliders from the projections 240, 242 and 24-1.

In the variation of Fig. 11, a cavity wheel 320 has a row of cavity portions 360 formed in the outer periphery thereof for co-operating with a row of cavity portions 370 in the inner surface of an outer band 334 to form cavities in the shape of a bolt. An inner band 332 contained within channels 368 and 369 formed in the engaging surfaces of the cavity wheel 330 and the band 334 extends into inner edges of the cavities formed by the cavity portions 360 and 370 to form a slot in the head portions of the bolts moulded in the cavities. Injection passages 374 are provided through the band 334 for injecting moulding material into the cavities. As shown, the rows of cavities 360 and 370 may be duplicated to form two rows of cavities for forming bolts.

In the variation of Fig. 12, an outer band 434 has rows of cavity portions 470 for forming the heads of nails while bores 460 extend into the cavity wheel 430 for forming the lower portion of the shaft of the nails. Openings 462 formed through the inner bands 432 form an upper portion of the shaft of the nail adjacent to the head portions. Injection passages 474 open into the cavity portons 470 for admitting moulding material. Teeth 488 and 494 on the cavity wheel 430 engage teeth 490 and 492 on the respective bands 434 and 432 to maintain registration of the bands 432 and 434 with the cavity wheel 430 during the angle of engagement. In operation of the variation of Fig. 12, the band 432 strips the nail formed within the cavities from the cavity wheel 430 as the band 432 disengages the cavity wheel 430. The nails are then removed from the inner band 432.

In the variation of Figs. 13 and 14, stripping wires or bands 532 and 533 are provided within grooves extending in the cavity wheel 530. Cavities 570 for forming a moulded part, for example a snap component, are formed in the inner surface of the band 534 and communicate by an injection mouldinq passage 574 to the outer surface of the band 534 for receiving injected moulding material as the cavitiy wheel 530 and bands 532 and 534 rotate through an angle of engagement. The bands extend along the bottom surface of the cavities formed between the cavity wheel 530 and the outer band 534. Grooves 564 and 565 formed in the cavity wheel 530 provide for the production of connecting strips joining series of the components or parts moulded in the cavities together. In operation of the variation of Figs 13 and 14, connecting strips are formed in the grooves 564 and 565 joining parts being continuously moulded in the cavities formed by the cavity portions 570 and bands 532 and 534 during rotation through the angle of engagement. The bands 532 and 534, after the angle of engagement, separate the continuous connected string of parts moulded in the cavities defined by the cavity wheel 530 and bands 532, 533 and 534 from the cavity wheel.

In the variation of Figs. 15 and 16, a cavity wheel 630 and a band 634 have respective rows of registrable cavities 660 and 670 for forming pulls for sliders of slide fasteners. Inner bands 632 and 633 in the form of wires are provided in respective annular grooves of the cavity wheel 630 for forming portions of bottom surfaces of the pulls and for removing the pulls from the cavities of the cavity wheel 630 upon disengagement of the bands 632 and 633 from the cavity wheel 630.

Since many modifications, variations and changes may be made to the embodiments described above and shown in the accompanying drawings, it is intended that all matter in the foregoing description and in the drawings be interpreted as illustrative and not in a limiting sense.

Claims

CLAIMS :

1. A method of continuously moulding articles, comprising rotating a cavity wheel having a row of first cavity-defining portions extending around the wheel periphery; rotating an inner continuous band which

2. A method as claimed in claim 1, comprising positioning the inner band in a channel in the cavity wheel so that the second cavity-defining portions 20 extend into a portion of the mould cavities, and closing the mould cavities by covering the first and second cavity-defining portions with the outer band.

3. A method as claimed in claim 1 or claim 2 comprising injecting the hardenable material through 25 openings in the outer band into the mould cavities; feeding a continuous carrier member into a channel in the periphery of the cavity wheel prior to bringing the wheel and bands together, the carrier member projecting into the mould cavities so that the articles are moulded on to the 30 carrier member.

4. A method as claimed in any of claims 1 to 3 wherein the second cavity-defining portions of the inner band extend between sections of the first and second cavity portions, and the inner surface of the outer band 35 engages a portion of an outer surface of the inner band to hold the inner band against the cavity wheel.

5. A method as claimed in claim 4 wherein the articles are slide fastener coupling elements moulded onto a carrier tape, and the method comprises feeding the 40 carrier tape into a channel in the periphery of the cavity wheel prior to bringing the wheel and band together so that the tape overlaps the mould cavity portions in the cavity wheel, the cavity-defining portions of the inner band being arranged to produce tab-engaging slots in head portions of the coupling elements. 5 encircles the wheel and which has in it second cavitydefining portions; rotating an outer continuous band which has third cavity-defining portions and which encircles the inner band and the cavity wheel; continuously bringing together portions of the inner and

6. A method of continuously moulding articles V substantially as herein described with reference to the drawings. 5

7. Apparatus for continuously moulding articles, comprising a cavity wheel having around its periphery a row of first cavity-defining portions, an inner continuous rotatable band encircling the cavity wheel and having a circumference larger than the periphery of the cavity wheel, an outer con10 tinuous rotatable band encircling the inner band and the cavity wheel and having a circumference larger than the circumference of the inner band, means for holding the inner and outer bands and the periphery of the cavity wheel together in engagement through an angle of engagement through which the bands and 15 cavity wheel rotate, the inner and outer bands having second and third cavity-defining portions, respectively, which with said first cavity-defining portions form moulding cavities for the articles in the angle of engagement, and means for injecting hardenable material into the so formed moulding cavities 20 to harden in the cavities. «

8. Apparatus as claimed in claim 7 wherein the cavity wheel has a channel for receiving the inner band, and the outer band extends to cover the inner band and the periphery of the cavity wheel, the bands having to maintain registration 25 of the inner and outer bands relative to each other and to the cavity wheel during moulding, and the inner band having projections for forming core members extending into cavities formed by outer band and the cavity wheel.

9. Apparatus as claimed in claim 7 or claim 8 30 including a second inner continuous rotatable band encircling the cavity wheel and having a circumference larger than the periphery of the cavity wheel, said second inner band having fourth cavity defining portions which with said first, second and third cavity defining portions form moulding cavities for 35 the articles in the angle of engagement.

10. Apparatus as claimed in claim 9, wherein the moulding cavities are adapted to produce sliders of slide fasteners. 10 outer bands and the periphery of the cavity wheel as they rotate so that their cavity portions form mould cavities and maintaining the cavity portions in register as the parts rotate through an angle of engagement; injecting hardenable material into the mould cavities; and 15 hardening the hardenable material in the mould cavities to form the articles.

11. An apparatus as claimed in claim 7 wherein the 40 moulding cavities are adapted to produce slide fastener retainers, or pulls for slide fasteners, or slide fastener coupling elements.

12. An apparatus as claimed in claim 7 wherein the moulding cavities are adapted to produce fasteners or bolts or nails.

13. Apparatus for continuously moulding articles, ’ 5 ' which apparatus is substantially as described with reference to and as shown in Figs. 1 to 6, or these Figs, as modified by Figs. 7 and 8, or Figs. 9 and 10, or Fig. 11, or Fig. 12, or Figs. 13 and 14, or Figs. 15 and 16, or Fig. 17 of the drawings.