Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
TECHNICAL FIELD
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The present invention relates to methods and
apparatus for continuously molding articles and particular-
ly to such methods and apparatus employing continuously
rotating cavity wheels and bands for orming cavities into
which the molding material is injected.
DESCRIPTION OF THE PRIOR ART
The prior art, as exemplified in U. S. Patents
No. 2,511,402, No. 3,917,787, No. 4,096,225, No. 4,084,296
and No. 4,137,034, Great Britain Patent Specification No.
533,711 and West German Offenlegungsschrift 2,027,963,
contains a number of methods and apparatus for continuously
molding articles including articles such as slide fastener
coupling elements. Some of these prior art methods and
apparatus employ continuously rotatable cavity wheels and/
or continuous bands for forming portions of the walls of
cavities into which the molding material is injected.
However, these prior art molding methods and apparatus
were limited to molding rather simple shapes since the
cavities and/or bands could only employ two mating mold
portions to form a molding cavity; in contrast prior art
molding employing reciprocating mold parts which are closed
could be provided with core elements and the like to form
articles with cavities or other complex shapes.
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Slide fastener coupling elements with tabs for
engaging slots in tops of opposite mating coupling elements
are shown in U. S. Patent No. 3,886,634.
SUMMARY OF THE INVENTION
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The invention is summarized in a method of con-
tinuously molding articles, including rotating a cavity
wheel having a row of first cavity-defining portions ex-
tending continuously in a peripher~ thereof; rotating an
inner continuous band with second cavity-defining portions
around the cavity wheel; rotating an outer continuous
band with third cavity-defining portions around the inner
band and the cavity wheel; continuously engaging portions
of the inner and outer bands and the periphery of the
cavity wheel together as the periphery of the cavity wheel
and the inner and outer bands rotate through an angle of
engagement; the engaging including the forming of molding
cavities defined by the first, second and third cavity
de:fining portions; injecting hardenable material into the
molding cavities; and hardening the hardenable material
in the molding cavities to form articles.
~ n ob~ect o the invention is to improve the
continuous molding of articles enabling the formation of
complex shapes and/or expeditious removal of articles from
a cavity wheel.
Anothe:r object of the invention is to provide
for forming slots, cavities, etc. in central portions of
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articles molded by means of cavity wheels, bands, and the
like.
One advantage of the invention is that the form-
ing of molding 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 por-
tions to mold complex or hollow shapes.
Another advantage of the invention is that an
inner band or bands can provide improved stripping of
molded 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 th~
accompanying drawings.
BRIB DESCRIPTION OF THE DRAWINGS
Fig. 1 is a diagrammatical plan view of a molding
apparatus in accordance with the invention.
Fig. 2 is a section view taken at line 2-2 in
Fig. 1 and enlarged from Fig. l of a portion of the molding
apparatus.
Fig. 3 is a further enlarged sectional view of a
broken-away portion of the structure shown in Fig. 2.
Fig. 4 is a perspective view of a broken-away
portion of the molding apparatus of Fig. 1
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Fig. 5 is a plan view of one broken-away portion
of a cavity wheel in the apparatus of Figs. 1-4.
Fige 6 is a plan view of a broken-away portion
o an outer band of the apparatus of Figs. 1-4.
Fig. 7 is a cross-sectional view of a broken-away
portion of a second variation of khe molding apparatus in
accordance with the invention.
Fig. 3 is a plan view of a broken away segment
of the periphery of the cavity wheel and inner band of the
apparatus of Fig. 7.
Fig. 9 is a cross-sectional view similar to Fig. 7
but of a third variation of the molding ap~aratus.
Fig. 10 is a plan view of a broken-away segment
of a periphery of a cavity wheel with a pair of inner bands
in the apparatus of Fig. 9.
Fig. 11 is a cross-sectional view of a broken-away
portion of a fourth variation of the molding apparatus,
Fig. 12 is a cross-sectional view similar to Fig.
11 but of a fifth variation of the molding apparatus~
` Fig~ 13 is a cross-sectional view similar to Figs.
11 and 12 but of a sixth variation of the molding
apparatus.
Fig. 14 is a plan view of a broken away segment
of the outer periphery of the cavity wheel with a pair of
stripping bands from the molding apparatus of Fig~ 13
showing a molded article thereon.
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Fig. 15 is a cross~sectional view similar to
Figs. 11-13 but of a seventh vari.ation of the molding
apparatus.
Fig. 16 is a plan view similar to Fig. 14. but
of the v~riation o~ Fig. 15.
Fig. 17 is a sectional view of a broken-away
- portion of a modification o~f the apparatus of Fig. 2.
D~SCRIPTION OF THE PREFERRED EMBODIME~TS
As illustrated in Fig. 1, an apparatus employing
the invention includes a cavity wheel 30, an inner band 32
extending around the cavity wheel 30~ an outer band 34
extending around 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
15: band 34 and inner band 32 against the cavity wheel 30 within
an angle of engagement 41. The cavity wheel 30 and bands
32 and 34 are continuously rotated in the same directi.on
past the injection mechanism 36 and the roller 40 so that
within the angle o engagement 41 the bands 32 dnd 34 and
the cavity wheel 30 are continuously held in engagement.
The cavity wheel 30 and the bands 32 and 34, where
.engaged together in the angle of engagement 41, form
molding cavities for receiving molding material which
is hardened therein to continuously form articles.
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The molding apparatus shown in Figs. 1-6 is
particularly desiyned for molding 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 mold
retainers for slide fasteners, the variation of Figs. 9
and 10 is designed to mold sliders for slide fasteners,
the variation of Fig. 11 is designed to mold bolts, the
variation of Fig. 12 is designed to mold nails, the vari-
ation of Figs. 13 and 14 is designed to mold parts 542,
e.g. snap eleme~ts, and th~ variation of Figs. 15-16 is
designed to mold pulls 642 for sliders of a slide fastener.
Many other variations can be devised for molding various
other articles.
In the apparatus of Figs. 1-6 for molding coupling
elements 42 and 44 on inner edges of slide fastener tapes 46
and 48, the cavity wheel 30 includes an outer annular member
50 suitably mounted on inner wheel members 52, 54 and 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 lower portions of the respective
aoupling elements 42 and 44. Annular channels 64 and 66 are
formed in the periphery in the wheel member 50 and have in-
ner 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
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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 po:rtions 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 the molding apparatus to define grooves
in the heads of the respective coupling elements 42 and 44.
The recesses or cavities 60 and 62 contain tongue-forming
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 gat`e portions 76 and 78
communicating with inner portions of the cavities 70 and
72.
For maintaining registration and alignment of the
band 34 relative to the wheel 30, an outward extending
annular flange 80 is formed on one side edge of the outer
periphery of the member 50 r and an annular ring member 82
is mounted in a groove on the opposite edge o~ the wheel
30. The flange 80 has an outer beveled surface 84 and
a inner surface 86 extending perpendicular to the axis of
rotation of the wheel 86 for engaging and positioning the
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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 und~lations 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 t'ne member 82, teeth 88 and teeth 90 of
Fig. 2~
As shown in Fig. 1 it is noted that, in the angle
of engagement 41, the upper surface oF the tapes 46 and 48
and the 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
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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 band~ 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 teekh or undulations 88
formed on the outer edge of the cavity wheel. Flange 80 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 60 and cavities 7Q together with the left edge
(as viewed in Figs. 2-4) oP the inner band 32 form
cavities for molding the coupling elements 42 while the
cavities 62 and 72 together with the right edge of the inner
band 32 form cavities for molding the coupling elements 44
on the inner edge of the tape ~8. Molten thermoplastic
or other molding material is injected by the injection
mechanism 3~ through the openings 74 and gates 76 and 78
into the respective cavities as the cavities pass the
molding mechanism 38. Subsequently the injected molding
material is hardened as engaging portions of the cavity
wheel 30 and bands 32 and 34 continue to rotate through
the angle oP engagement 41; for example, molten thermo-
plastic is cooled and solidified by contact with the
cavity wheel 30 and bands 32 and 34.
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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 molding
wheel. The coupling elements 42 and 44 are broken apart and
palled 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 cavitles 70
and 72 of the band 34.
The employment of rotating cavity wheels, inner
and outer bands to form cavities for molding articles
permits continuous molding of complicated shapes by
utilizing inner band members as core members for making
complex shapes.
In 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 molding 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
molding 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 for molding
material. The inner band 132 has projections 140
which extend into central portions of the cavities formed
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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 which mate ~ith
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 regis-
tration teeth 192 which engagG 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 de-
fined by the cavity wheel 130 and bands 132 and 13~ in the
angle of engagement by injecting and hardening molding
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 molding
cavities to form sliders for a slide fastener. The cavity
wheel 230 has a continous row of cavity portions 260 de-
signed 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 234 to form upper portions of the
sliders. The cavity portions 270 communicate with input
injection passages 274 which open in the upper surface
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of the band 234. The band 232 has core projections 240
whiIe 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 orm the flanges on the
slider~ for engaging the heels of the coupling elements.
Engaging teeth 288 and 290 on the respective cavity wheel
230 and band 234 provide or registration of the band 234
relative to the cavity wheel 230. Teeth 292 and 296 on the
respective bands 232 and 233 mate with teeth 294 and 298
formed in the cavity wheel 230 to maintain registration of
the bands 232 and 233 relative to the cavity wheel 230 and
the outer band 234. In operation of the variation of the
Figs. 9 and 10, the inner bands are separated after
disengaging the cavity wheel 230 to permit removal of the
sliders rom the projections 240, 242 and 244.
In the variation of Fig. 11, a cavity wheel 330
has a row of cavity portions 360 formed in the outer
periphery thereof for cooperating 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 molded in the cavities. Injection passayes
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374 are provided through the band 334 Eor injecting mold-
ing material into the cavities. As shown, the row~ 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. Open-
ings 462 formed through the inner bands 432 form an upper
portion of the shaft of the nail adjacent to the head por-
tions. Injection passages 474 open into the cavity portions
470 for admitting molding material. Teeth 488 and 494 on
the cavity wheel 430 engage teeth 490 and 492 on the respec-
tive bands 434 and 432 to maintain registration of the bands
15 432 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 cavit~
wheel 430. The nails are then removed from the inner band
20 432.
In the variation of Figs. 13 and 14, stripping
wires or bands 532 and 533 are provided within grooves ex-
tending in the cavity wheel 530. Cavities 570 for forming
a molded part, for example a snap component, are formed in
the inner surface of the band 534 and communicate by an
injection molding passage 574 to the outer surface of the
band 534 for receiving injected molding material as the
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cavity wheel 530 and bands 53~ and 534 rotate through an
angle of engagement. The bands e~tend 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 con-
necting strips joining series of the components or parts
molded in the cavities together. In operation of the vari-
ation of Figs. 13 and 14, connecting strips are formed in
the grooves 564 and 565 joining parts being continuously
molded in the cavities formed by the cavity portions 570
and bands 532 and 534 druing rotation through the angle of
engagement. The bands 532 and 534, after the angle of
engagement, separate the continuous connected string of
parts molded 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
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in the foregoing description and in the drawings be
int~rpreted as illustrative and not in a limiting sense.
