CA2086518A1 - Insert molding for non-rigid encapsulated components - Google Patents
Insert molding for non-rigid encapsulated componentsInfo
- Publication number
- CA2086518A1 CA2086518A1 CA002086518A CA2086518A CA2086518A1 CA 2086518 A1 CA2086518 A1 CA 2086518A1 CA 002086518 A CA002086518 A CA 002086518A CA 2086518 A CA2086518 A CA 2086518A CA 2086518 A1 CA2086518 A1 CA 2086518A1
- Authority
- CA
- Canada
- Prior art keywords
- interior
- cavity
- blade
- mold
- rigid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14065—Positioning or centering articles in the mould
- B29C45/14073—Positioning or centering articles in the mould using means being retractable during injection
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14639—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles for obtaining an insulating effect, e.g. for electrical components
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Moulds For Moulding Plastics Or The Like (AREA)
- Injection Moulding Of Plastics Or The Like (AREA)
Abstract
An injection molding technique is disclosed in which non-rigid or flexible components intended to be encapsulated within an interior of an injection molded product are held in postion in an interior of a mold cavity (11) during the injection operation by thin, rigid forks or blades (23, 24, 25) with surfaces interior to mold cavity contoured to mate with and capture the non-rigid, flexible component (17, 19). Such forks or blades can be retracted prior to the final packing portion of the molding cycle to allow plastic flow into the void left by the retracted blades, or the blades can be retracted after the end of the injection cycles and voids left in the molded product. Portions of the encapsulated components themselves can be fashioned to capture and hold portions of other encapsulated components during the injection process.
Description
--W~92/~0~40 20~6.~8 PCr/US91/04673 INSERT MOLDIN& FOR Nl)N-RIGID ENCAPSULATED CO~PON3 :NTS
Teehnie~l Field This inven~on relates to methods and ~a.~lus for plas~c injection mol~lin~, and, more particularly, ~o molded plas~c pl~lu~l~ wi~ non-5 rigid e...i~ t~y3 CO.I.1X"~ and m~thodc o making such pro~ucts.
R~srl~ l of t~e I~ ;DI-It is well lmown to çn~ps~ t~ cc l.pc,l1e~ thin a plas~c mol~ling die ca~rity by rigidly affi~ng such cY"..l~o~ c to or ~rough ~e wa~ls of ~e c~ . It is also hlown to avoid ~e ~yy~aace of holding devioes at ~e 10 surfau of the molded product by pro~riding retractable holding deYic~s which retrac~ out of ~e mol lin~ ca~ity while ~e m~'1in~ m~to.ri~l iS l'setting Up." An f - .'C of ~e latter t~chnillue is show~ in L. H. Moqin patent 3,420,929, gra~ted January 7, 1969. It is also possible for ~e holding devices to retract into the oen~er of the molded product, as shown in R. X. PiuLlv~y pa~ent 15 4,470,784, gran~ed September 11, 1984. Such p~ior art holding deYi~s and te~hn;q~lP.S, however, do not hold ~e ~n~rs~ ted c~ rne~t iIl a precisely de~ined posi~on, and hence are of limited ~ F.~ In some ~prlic~ ?n~> for .nl le, ~e P.nc~ tP~l c~ rl~ must ~ pqecise po~iiions Tela~ve to o~her e~ Sed c~ or with respect to the e~tenor (~UlliUU~:i of the 20 molded product.
The ~ Y~ of ~lecis~ oning enr~ tP11 within an inje~;liun m~' 1ing cavity can be further cnml lic~f~l by two ~dtlitir~n~l facto~s. If ~e ~~ on l to be en~ tPfl is not rigid, the problem of holding it in a precise ~Sion is far more rliffi~llt Fu~ e~l--ul~, ~e ~e tlimP.nci~m Of 25 ~he ~e molded product may be such that very li~e leeway e~s~; for pC~citiC-nin~
~e en~ll~tPA co...~n~.l away from the surfaces of ~e mold. If ~e l is not precisely and firmly pociti~np~l in the interior of a ~in mr'1in~
cavity, for e~mrle, a },.~blt;~l called "cu~ l breakout" occurs in which some or all of the enc~rsnl~tP~ co ,l~onelll is visible at ~e surface o~ the molded 30 product. Such bqe~Xout is normally grounds for rejecting the product.
.... , - ~ -. .
;,~ , ' ' '~' , .
' :: ~ ' --wo g~o~o 2 ~ 8 ~ Pcr/u~sl/o4673 Su~ o~ the l~ liu~
In a~.dallce wi~ the ii~ dliVe emhQ~ r~ of the present i~lvt;lllio~ nr~pyll~t~A cr..~ o.,~ d particularly non-rigid ~nr~ tP~
cu~ ne~ , are ;al~tu~;d at a precise position in the interior of the mold cavityS by means of l~d~ble ~hin, flat, rigid '~lades" or "forks" ha~ing one end fab~icated with a contour which mates with and ~turcs the e~ ;l3~d cc"l,~ne~t. The blade or fork rigidly holds the enr~ tP~ at a precise position in the interior of ~he mold cavity during the plastic illj~lionprocess. Just before the last "packing'l portion of the injection mol~lin~ cycle, ~e 10 blades or forks can be rel~d~d to allow ~e molllin~ material to flow and fill ttle thin voids left by ~e blades or forks. To assist in rrlldcLio~ he blades are made as ~in as possible and yet m~;..l;.;~- s~ Pnt ngidity to hold the enr~I sul~t~i component in the precise posi~on desired. ~1 lr.l . .~;v~l~, the blades can be left in the mold uultil after the plastic mo! lin~ m~trri~l has set up, and 15 then wi~drawn, leaving very small, thin voids in the rnolded prcduct. This latter procedule is possible only if ~in slots left by ~e blades or forks do notadversely afEect ~e Il~P.r~ r~ or a ~ of ~e molded product.
~ ce wi~ one feat.ure of ~e invention, the blade or fork can be biased into ~e interior of ~e mol~ling cavity with a spring ~e force o~
20 which is ~vt~ e only by the higher ~ of ~e fimal "paeking" portion of ~e mnl-lin~ cycle. The blades or forks will ~en be a~ltom~ lly ejected from ~e mo~ ling cavity at ~lec.sely the correct time to permit filling the voids left behind by ~e ~ Ling ~lades during ~e packing period.
For conveDience~ ~e present invention w~ll be described in 25 c~ i;on wi~ ~e m~rling of an ultra thin el~trical plug in which the ~1r~l, ;ç~l wires mus~ lP~ in a precise position within ~e mold cavi~r to avoid '~eakout" of ~e ~nres to the su~ce of the molded plug. Such a plug is described, for ~ , in ~rplir~nt's patent 4,927,376, granted May 22, 1990, and ~ n~ to applicant's ~ccignP~ is to be understood, however, th2t the 30 methofls and appa~lus of the present invention can be applied to ~e injec~on mrl~lin~ of many o~er products, particularly ~JlOdU~ 4Uilillg the r~ tiQn and precise pocitif)ning 0~ non-rigid c~.l,.pcl.~
.. . . .. .
_ WO 92/00840 2 0 8 6 a ~ ~ P~/US91~04673 Brief De~cri~tion o~ $he D~
A ~ rlr~ g of the present invention may be gained by conci~1ering the foll~wing detailed d~liyli~l~ in ~ ;on with the ~ c(~ .yi~g L~wii~gs, in which: .
FIG. 1 shows a par~ally cut-a~ay pe ~ e view of the lower die of a plastic inj~ n mold showing the all ~ of both ngid and non-rigid ~o~.pn~m~ in~ cavity, and ~l~uwil~g the use of thin blades to hold elp~ wires in place du~ing the i ;ol~ opera'don;
FIG. 2 shows a p~ial cro~s-~chon~l ~riew of ~e injection mold ~f 10 FIG. 1 showing ~e posi~on-holding blades in the P,~en-le~l position holding non-rigid wires in a precise location l~lwæll the upper and lower surfaces of the mold cavi~;
FIG. 3 shows a par~al cross-sectional view of ~e molded product produced by the mold of Fl~. 2, showing one posi~on-holding blade;
FIG. 4 shows another partial cross-se~i~n~l view of ~e injection mold of FIG. 1 showing the position-holding blade l~l~d~ t;d;
FIG. S shows a par~al cross-se~iQn~l ~qew of ~e molded p~oduct u~d by ~e mold of FIG. 4 with ~e posi~on-holding blade l~tldCIl;d;
FIG. 6 shows a ~~ iV~ par~al se~inn~l ~ew of a molàed 20 ~ree-prong el~i~l plug molded ~ usi~g the position-holding blades of the present invention and tab clips on one of the ~lP~ir~ ongs to assist in holding the e~ nres in position dwing ~ie mol~lin~ process;
FIG. 7 sh~ws a ~oss-~ion~l view of ~e cavi~y mold used to p~oduce the molded product of lFlG. 6~ uwillg the posi~on-holding blades in 25 their i~P.n(lerl position; and FIG. 8 is a ~,~iiv~ view of ~e tab clips on ~e electric~
iground prong of ~G. 6 usecl to assist in holding the el~ l wire in posi~on du~ing ~e mr'1ine lprocess.
To fi~irili~te reader ~ in~ iden~ ert;lellce numerals are 30 used to fl~P~ te el~mPnts commcm to the figures.
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, . -... - :
-wo ~/oo~l) 2 0 ~ 6 .;. 1~ pcr/ussl/o4673 Det~iled Des~
~ FIG. 1 there is shovvn a ~ial pr,~ i;v~ view of the lowerdie 10 of a eavity injection mold c~ a mold half eavity 11 in ~e shape of a thin he~g~n~l electrical plug. Electrical prongs or c~ pins c~ n~ A to 5 5t~hili7inr lands 12 and 13 e~tend out of caYity ~ rough slots 14 and 15, ely. S;lots 14 and 15 have bottoms located so as to precisely position lands 12 and 13 in the interior of mold cavity 11. Tn~ ted wires 16 and 17 join ~oge~er in sleeve portio~l 18 of mold cavity 11 to farrn line oord 19. One end ~f ~nre 16 is elec~ically a~ rl~r~ to land 12 while one end of wire 17 is electrically 10 ~ rhP~l to land 13. In addition, wire 1~ is physically ~ hPA to land 12 by crimp 20 while wire 17 is physically ~ r~ to land 13 by crimp 21. An upper die, not shown in FIG. 1, has a half cavity ~ ul;ng cavity 11 in die 10, but without the slots for the electrical plugs. An inje~ion runner or half gate 22, together with the mating half gate on the upper die, forms a en~y ps~rt for 15 inj~ing a molten plastic such as polyvirlylchloride (PVC) into ~e ~c~.m~
mold.
~ practice, the two half cavities are r;~ r~A ti~dy t~gether in the core of a mol-lin~v m~rhin~-. Molten plastic is injected under high pl~lllG (5 150 tons per squa~e inch) to entirely fill all of the voids in the ~e mold cavi~.
20 At ~e very end of ~e n~ lin~ cycle, ~e injec~ion pl~U~t iS raised even higherfor a brief period to ensure eomr1ete filling of all voids in ~he cavity. This higher ~e5~UI~ at ~e end of the injec~on ~ycle is called ~e "packing' por~on of the injPrtion r~ol(lin~ cycle. After the plas~c Jn~tPn~l has cooled, possible assisted by cold w~ter arcula~ng in ~e inte~ior of ~e mold body, ~e mold is 2~ opened and the moldPA product is eje~ed from ~e mold by m~s of an ejection piston 26.
In a~u~ ~ wi~ the present invention, the wir~ 16 and 17 and the line cord 19 are ~u~ d in ~e interior of the mold cavity by a plurality of ~in metallic blades23, 24 and 25. As can be be~ter se~n in FI(:;. 3, the 30 blades 23-25 have a contour ~ormed into their upper edge which mates wi~h andes ~vire 16. That is, the upper edge of blade 24 has a contour which is slightly more than a haU of the periphery of wire 16 and ~us is able to "grab"
~e soft insulation of wire 16 and hold it in posi~on. Blade 23 has a conto~ in its upper edge which ma~es with the double wire line c~d 19 and also ~ nds . .
-3 2 0 8 ~ 3 ~ 8 PCr/U~91/04673 ~ S -beyond the ~ lar ~ y of ~e ~wo wire of line cord 19 to hold the line cord in position.
It will be noted that the caYity fs~ned by the two dies is ~ .ely ~in and henoe very little leeway is available for ~e ~ 1 of wires 16 and 17 S alld line cord 19 Wi~iIl the ca~ 11. If these wires are not placed I,l~ sely in the -,o~ g ca~ity, and held in ~at position during ~e enffre injec~on process, the wires will be moved by the a-lv~ci~g moltcn plastic and possibly end up being in contact wi~ ~e exterior surace of the mold cavity 11. When the molded plug is ~e~uvt;d from the mold cavity (by piston ~6, ~fG. 2) after the 10 molten plastic has hardened, any wires pushed to the surfac~ c)f the mold cavity are visible at the surface of ~e completed plug. This result is called 'wire brealcout" and is sl-ffir~ntly l-n~sthPtic to result in rejection of molded p~oducts exhibi~ng such ~nre breakout.
In accol~ce with ~e present inven~don, retractable p~i1inni 15 blades 23, 24 and 25 position the no~-rigid wires 16 and 17 and line cord 19 isely within the mold ca~ity and ~ - these non-rigid c~ r~ at th~t precise po~ition throughout ~e mol~lin~ process. The number ~d p~ nn~ of the blades such as blades 23-25 are direc~y s1e~ on ~e desired ~li~cff;itic~n of the wires wi~hin the ca~ and ~e length of the ~ivire runs ~U~illg support.
20 The ~ree blades 23-25 in FIG. 1 are s~ffirip.nt for the wires in ~e elPct~ir~l plug depicted ~erein.
Blades ~3-25 can be retrac~d, for PY~mpl~P. by hydraulic pistons, not shown, just before the pasking por~on of ~e m~ ing cycle so that ~e voids formed by the retracted blades can be, filled by ~he still flowing plastic matenal.
2~ ~AhPrn~tPly, and preferably, the blades 23-2S can be spring-loaded such that ~ey are held in ~e position-st~hiliring position for ~e ini~al portion of the injec~on cycle, but are pushed out of the mold cavity 11 by $he higher ~ e ~xerted d~ing ~e pacl~ng portion o~ ~e inj~ion cycle. As a ~er ~ ;Ye, the blades 23-25 can be retracted after ~e entire mnl~lin~ ~ycle is ~ ,ted, leaving 30 the ~in slots ~om which the blades are l~.lWVI~ in ~e ~ni~hPA molded product. If blades 23-25 are ~in enough and ~ocitionp~ so as to ~ , the a~ce - of such slots, it may not be llec~ y to fill ~e voids left by blades 23-25 at a:ll.
Indeed~ ~e surface of ~e finished product can be dec~,~Ced with slo$-iike dec~rations in ~e midst of which the actual blade slots become virtually .. . ~ . . - - --:::
, , wo g~o~l) 2 ~ Pcr/Us9 l /04673 invisible.
In FIG. ~ there is sh~n a partial cross-se~ion~l view of '~he ~cc~mhl~A mold cc.,..~ lower die 10 and a ma~ng upper die 27 forming the mold cavity 11 ~h~reb~ . The rl~ ong ~8 ~thched to land 12 S SU~ > land l2 in ~e interior of c~vity 11 while blades ~4 and 25 support wire 17 in the interior of cavity 11. FIG. 3 is a pardal cross-section of ~e molded plug 29 ~huwi~g the wire 17 s~ e~l therein and su~w~d by bl~de 24.
~ FIG. 4 there is shown a par~al cross-sechnn~l view of the same lQ ~ m~ l mold of FIG. 2, but with the positioning blad~ 23-25 retracted out of the mo' 1in~ cavity 11. In FIG. S t:here is shown a partial cross-section of ~hemolded plug 29 with the wire 17 sus~n-1pt~l in ~e hardened plastic and wi~ the ~7.~ g blades 23-2S removed, leaving cavi~ void 30. As noted above, void 30 can be filled by retrac~ng the blade p~ior to the packing por~on of the 15 iniection cycle, or the void 30 can ~e left unfllled by retrac~ng ~e blade after the end of ~e injection cycle and after the plas~c has hardened.
Al~ough ~e me~od and ay~ of the p~esent inven~on for pc~ innin~ non-rigid cc,~ b in ~e interior of molded ~l~lu~, is shown in FIGS. 1-5 in c~ inn wi~ molded ele~rical plugs, it will be a~ i to 20 persons of olJin~ skill in the injection mollling art ~at this method and a~p~dlus can be used for positioning ~ in ~e int~or of many o~er molded products, whether rigid or non-ngid. Thin blades or forks are ~d having ~e edge interior to ~e mold cavity colllouled to match the exterior surface of the c~l"~nc~t to be positioned. Such blades or forks can be used to 253 ~e~i~ly position a large number of enc~rs~ ed c~n.l~n~ wi~in ~e interior of molded plas~c products without d~alLing from the spirit or scope of ~is inven~don.
~ 4hhnllgh the technique d~ in co~ with FIGS. 1-5 san be used to position many S~ir~ ~ pes of C~ X wi~in the interior 30 molded products, it is also possible to make use of one or more of the enr~lll~t~i cnmrnPnt~ itself to assist in positioning a .liff~.e~ nr~rS~ t~d c~ r.~t Such and elrtt.n-led positioning techni~que is r~ o~d in FIG. 6-8 in co,llle-;lion with a ~ree-pronged, grounded molded elec~ica~ plug.
. _ . .
o ~ g WO 9~/00840 PCl/US91/04673 In FIG. 6 there is shown a ~livt; view, in par~al section, of a three-prorlg el~;Llieal plug ~l~rir2~çrl by inir~hon mol~ing techniques in aecolda~ce with ~e present il~v~lllion. The plug body 40 enr~psul~t~c the ~ee wires of ~e three-wsre line ~ord 41 as well as st~hili7ing lands for ground pin 42 S and power pins in~ tlin~ pin 43 and a second power pin, not visible in FIG. 6.The upper por~on of ground pin 42 has two channel-formitlg l:abs 44 and 45 used to assist in ~uling the el~1~ical wire 46 cn.~ ~i to power pin 43. Thin blades with a~lu~ lcl~ col~uurt;d upper edges ~re also used to assist in po~itioning wire 46 in other portions of the mbld ~vit~. The mold cavity is 10 shown in cross-s~tion in PIG. 7.
In FIG. 7, the two half molds 50 and S1 define a mold cavity 52 îL.,Ic;belween in which wire 46 is positioned in par~ by bladP~ 53 and ~4 and inpart by the upper por~on of ground pin 42, shown in perspective view in FIG. B.
The tabs 44 and 45 capture wire 46 to hold wire 46 in position during the 15 m~ing process. Since wire 46 is fully in~ tPIl, the contact by tabs 44 and 45 does not i~ r~.e wi~ the PhP~i~l circuit. A çrimpi~ land 56 is also ~chion~d on grou~d pin 42 to provide a pl2Ce to e~ ly alnd me~h~ni~11y connect ~e ground wire of line cord 41 to ~e ground pin 42.
It should be clear to ~ose skilled in ~e art that further 20 emho~limp~rts of ~e present invention may be made by ~ose sldlled in ~e art without d~ g from ~e tP~in~ of the presP~nt invention.
Teehnie~l Field This inven~on relates to methods and ~a.~lus for plas~c injection mol~lin~, and, more particularly, ~o molded plas~c pl~lu~l~ wi~ non-5 rigid e...i~ t~y3 CO.I.1X"~ and m~thodc o making such pro~ucts.
R~srl~ l of t~e I~ ;DI-It is well lmown to çn~ps~ t~ cc l.pc,l1e~ thin a plas~c mol~ling die ca~rity by rigidly affi~ng such cY"..l~o~ c to or ~rough ~e wa~ls of ~e c~ . It is also hlown to avoid ~e ~yy~aace of holding devioes at ~e 10 surfau of the molded product by pro~riding retractable holding deYic~s which retrac~ out of ~e mol lin~ ca~ity while ~e m~'1in~ m~to.ri~l iS l'setting Up." An f - .'C of ~e latter t~chnillue is show~ in L. H. Moqin patent 3,420,929, gra~ted January 7, 1969. It is also possible for ~e holding devices to retract into the oen~er of the molded product, as shown in R. X. PiuLlv~y pa~ent 15 4,470,784, gran~ed September 11, 1984. Such p~ior art holding deYi~s and te~hn;q~lP.S, however, do not hold ~e ~n~rs~ ted c~ rne~t iIl a precisely de~ined posi~on, and hence are of limited ~ F.~ In some ~prlic~ ?n~> for .nl le, ~e P.nc~ tP~l c~ rl~ must ~ pqecise po~iiions Tela~ve to o~her e~ Sed c~ or with respect to the e~tenor (~UlliUU~:i of the 20 molded product.
The ~ Y~ of ~lecis~ oning enr~ tP11 within an inje~;liun m~' 1ing cavity can be further cnml lic~f~l by two ~dtlitir~n~l facto~s. If ~e ~~ on l to be en~ tPfl is not rigid, the problem of holding it in a precise ~Sion is far more rliffi~llt Fu~ e~l--ul~, ~e ~e tlimP.nci~m Of 25 ~he ~e molded product may be such that very li~e leeway e~s~; for pC~citiC-nin~
~e en~ll~tPA co...~n~.l away from the surfaces of ~e mold. If ~e l is not precisely and firmly pociti~np~l in the interior of a ~in mr'1in~
cavity, for e~mrle, a },.~blt;~l called "cu~ l breakout" occurs in which some or all of the enc~rsnl~tP~ co ,l~onelll is visible at ~e surface o~ the molded 30 product. Such bqe~Xout is normally grounds for rejecting the product.
.... , - ~ -. .
;,~ , ' ' '~' , .
' :: ~ ' --wo g~o~o 2 ~ 8 ~ Pcr/u~sl/o4673 Su~ o~ the l~ liu~
In a~.dallce wi~ the ii~ dliVe emhQ~ r~ of the present i~lvt;lllio~ nr~pyll~t~A cr..~ o.,~ d particularly non-rigid ~nr~ tP~
cu~ ne~ , are ;al~tu~;d at a precise position in the interior of the mold cavityS by means of l~d~ble ~hin, flat, rigid '~lades" or "forks" ha~ing one end fab~icated with a contour which mates with and ~turcs the e~ ;l3~d cc"l,~ne~t. The blade or fork rigidly holds the enr~ tP~ at a precise position in the interior of ~he mold cavity during the plastic illj~lionprocess. Just before the last "packing'l portion of the injection mol~lin~ cycle, ~e 10 blades or forks can be rel~d~d to allow ~e molllin~ material to flow and fill ttle thin voids left by ~e blades or forks. To assist in rrlldcLio~ he blades are made as ~in as possible and yet m~;..l;.;~- s~ Pnt ngidity to hold the enr~I sul~t~i component in the precise posi~on desired. ~1 lr.l . .~;v~l~, the blades can be left in the mold uultil after the plastic mo! lin~ m~trri~l has set up, and 15 then wi~drawn, leaving very small, thin voids in the rnolded prcduct. This latter procedule is possible only if ~in slots left by ~e blades or forks do notadversely afEect ~e Il~P.r~ r~ or a ~ of ~e molded product.
~ ce wi~ one feat.ure of ~e invention, the blade or fork can be biased into ~e interior of ~e mol~ling cavity with a spring ~e force o~
20 which is ~vt~ e only by the higher ~ of ~e fimal "paeking" portion of ~e mnl-lin~ cycle. The blades or forks will ~en be a~ltom~ lly ejected from ~e mo~ ling cavity at ~lec.sely the correct time to permit filling the voids left behind by ~e ~ Ling ~lades during ~e packing period.
For conveDience~ ~e present invention w~ll be described in 25 c~ i;on wi~ ~e m~rling of an ultra thin el~trical plug in which the ~1r~l, ;ç~l wires mus~ lP~ in a precise position within ~e mold cavi~r to avoid '~eakout" of ~e ~nres to the su~ce of the molded plug. Such a plug is described, for ~ , in ~rplir~nt's patent 4,927,376, granted May 22, 1990, and ~ n~ to applicant's ~ccignP~ is to be understood, however, th2t the 30 methofls and appa~lus of the present invention can be applied to ~e injec~on mrl~lin~ of many o~er products, particularly ~JlOdU~ 4Uilillg the r~ tiQn and precise pocitif)ning 0~ non-rigid c~.l,.pcl.~
.. . . .. .
_ WO 92/00840 2 0 8 6 a ~ ~ P~/US91~04673 Brief De~cri~tion o~ $he D~
A ~ rlr~ g of the present invention may be gained by conci~1ering the foll~wing detailed d~liyli~l~ in ~ ;on with the ~ c(~ .yi~g L~wii~gs, in which: .
FIG. 1 shows a par~ally cut-a~ay pe ~ e view of the lower die of a plastic inj~ n mold showing the all ~ of both ngid and non-rigid ~o~.pn~m~ in~ cavity, and ~l~uwil~g the use of thin blades to hold elp~ wires in place du~ing the i ;ol~ opera'don;
FIG. 2 shows a p~ial cro~s-~chon~l ~riew of ~e injection mold ~f 10 FIG. 1 showing ~e posi~on-holding blades in the P,~en-le~l position holding non-rigid wires in a precise location l~lwæll the upper and lower surfaces of the mold cavi~;
FIG. 3 shows a par~al cross-sectional view of ~e molded product produced by the mold of Fl~. 2, showing one posi~on-holding blade;
FIG. 4 shows another partial cross-se~i~n~l view of ~e injection mold of FIG. 1 showing the position-holding blade l~l~d~ t;d;
FIG. S shows a par~al cross-se~iQn~l ~qew of ~e molded p~oduct u~d by ~e mold of FIG. 4 with ~e posi~on-holding blade l~tldCIl;d;
FIG. 6 shows a ~~ iV~ par~al se~inn~l ~ew of a molàed 20 ~ree-prong el~i~l plug molded ~ usi~g the position-holding blades of the present invention and tab clips on one of the ~lP~ir~ ongs to assist in holding the e~ nres in position dwing ~ie mol~lin~ process;
FIG. 7 sh~ws a ~oss-~ion~l view of ~e cavi~y mold used to p~oduce the molded product of lFlG. 6~ uwillg the posi~on-holding blades in 25 their i~P.n(lerl position; and FIG. 8 is a ~,~iiv~ view of ~e tab clips on ~e electric~
iground prong of ~G. 6 usecl to assist in holding the el~ l wire in posi~on du~ing ~e mr'1ine lprocess.
To fi~irili~te reader ~ in~ iden~ ert;lellce numerals are 30 used to fl~P~ te el~mPnts commcm to the figures.
-.. . . . . . .
, . -... - :
-wo ~/oo~l) 2 0 ~ 6 .;. 1~ pcr/ussl/o4673 Det~iled Des~
~ FIG. 1 there is shovvn a ~ial pr,~ i;v~ view of the lowerdie 10 of a eavity injection mold c~ a mold half eavity 11 in ~e shape of a thin he~g~n~l electrical plug. Electrical prongs or c~ pins c~ n~ A to 5 5t~hili7inr lands 12 and 13 e~tend out of caYity ~ rough slots 14 and 15, ely. S;lots 14 and 15 have bottoms located so as to precisely position lands 12 and 13 in the interior of mold cavity 11. Tn~ ted wires 16 and 17 join ~oge~er in sleeve portio~l 18 of mold cavity 11 to farrn line oord 19. One end ~f ~nre 16 is elec~ically a~ rl~r~ to land 12 while one end of wire 17 is electrically 10 ~ rhP~l to land 13. In addition, wire 1~ is physically ~ hPA to land 12 by crimp 20 while wire 17 is physically ~ r~ to land 13 by crimp 21. An upper die, not shown in FIG. 1, has a half cavity ~ ul;ng cavity 11 in die 10, but without the slots for the electrical plugs. An inje~ion runner or half gate 22, together with the mating half gate on the upper die, forms a en~y ps~rt for 15 inj~ing a molten plastic such as polyvirlylchloride (PVC) into ~e ~c~.m~
mold.
~ practice, the two half cavities are r;~ r~A ti~dy t~gether in the core of a mol-lin~v m~rhin~-. Molten plastic is injected under high pl~lllG (5 150 tons per squa~e inch) to entirely fill all of the voids in the ~e mold cavi~.
20 At ~e very end of ~e n~ lin~ cycle, ~e injec~ion pl~U~t iS raised even higherfor a brief period to ensure eomr1ete filling of all voids in ~he cavity. This higher ~e5~UI~ at ~e end of the injec~on ~ycle is called ~e "packing' por~on of the injPrtion r~ol(lin~ cycle. After the plas~c Jn~tPn~l has cooled, possible assisted by cold w~ter arcula~ng in ~e inte~ior of ~e mold body, ~e mold is 2~ opened and the moldPA product is eje~ed from ~e mold by m~s of an ejection piston 26.
In a~u~ ~ wi~ the present invention, the wir~ 16 and 17 and the line cord 19 are ~u~ d in ~e interior of the mold cavity by a plurality of ~in metallic blades23, 24 and 25. As can be be~ter se~n in FI(:;. 3, the 30 blades 23-25 have a contour ~ormed into their upper edge which mates wi~h andes ~vire 16. That is, the upper edge of blade 24 has a contour which is slightly more than a haU of the periphery of wire 16 and ~us is able to "grab"
~e soft insulation of wire 16 and hold it in posi~on. Blade 23 has a conto~ in its upper edge which ma~es with the double wire line c~d 19 and also ~ nds . .
-3 2 0 8 ~ 3 ~ 8 PCr/U~91/04673 ~ S -beyond the ~ lar ~ y of ~e ~wo wire of line cord 19 to hold the line cord in position.
It will be noted that the caYity fs~ned by the two dies is ~ .ely ~in and henoe very little leeway is available for ~e ~ 1 of wires 16 and 17 S alld line cord 19 Wi~iIl the ca~ 11. If these wires are not placed I,l~ sely in the -,o~ g ca~ity, and held in ~at position during ~e enffre injec~on process, the wires will be moved by the a-lv~ci~g moltcn plastic and possibly end up being in contact wi~ ~e exterior surace of the mold cavity 11. When the molded plug is ~e~uvt;d from the mold cavity (by piston ~6, ~fG. 2) after the 10 molten plastic has hardened, any wires pushed to the surfac~ c)f the mold cavity are visible at the surface of ~e completed plug. This result is called 'wire brealcout" and is sl-ffir~ntly l-n~sthPtic to result in rejection of molded p~oducts exhibi~ng such ~nre breakout.
In accol~ce with ~e present inven~don, retractable p~i1inni 15 blades 23, 24 and 25 position the no~-rigid wires 16 and 17 and line cord 19 isely within the mold ca~ity and ~ - these non-rigid c~ r~ at th~t precise po~ition throughout ~e mol~lin~ process. The number ~d p~ nn~ of the blades such as blades 23-25 are direc~y s1e~ on ~e desired ~li~cff;itic~n of the wires wi~hin the ca~ and ~e length of the ~ivire runs ~U~illg support.
20 The ~ree blades 23-25 in FIG. 1 are s~ffirip.nt for the wires in ~e elPct~ir~l plug depicted ~erein.
Blades ~3-25 can be retrac~d, for PY~mpl~P. by hydraulic pistons, not shown, just before the pasking por~on of ~e m~ ing cycle so that ~e voids formed by the retracted blades can be, filled by ~he still flowing plastic matenal.
2~ ~AhPrn~tPly, and preferably, the blades 23-2S can be spring-loaded such that ~ey are held in ~e position-st~hiliring position for ~e ini~al portion of the injec~on cycle, but are pushed out of the mold cavity 11 by $he higher ~ e ~xerted d~ing ~e pacl~ng portion o~ ~e inj~ion cycle. As a ~er ~ ;Ye, the blades 23-25 can be retracted after ~e entire mnl~lin~ ~ycle is ~ ,ted, leaving 30 the ~in slots ~om which the blades are l~.lWVI~ in ~e ~ni~hPA molded product. If blades 23-25 are ~in enough and ~ocitionp~ so as to ~ , the a~ce - of such slots, it may not be llec~ y to fill ~e voids left by blades 23-25 at a:ll.
Indeed~ ~e surface of ~e finished product can be dec~,~Ced with slo$-iike dec~rations in ~e midst of which the actual blade slots become virtually .. . ~ . . - - --:::
, , wo g~o~l) 2 ~ Pcr/Us9 l /04673 invisible.
In FIG. ~ there is sh~n a partial cross-se~ion~l view of '~he ~cc~mhl~A mold cc.,..~ lower die 10 and a ma~ng upper die 27 forming the mold cavity 11 ~h~reb~ . The rl~ ong ~8 ~thched to land 12 S SU~ > land l2 in ~e interior of c~vity 11 while blades ~4 and 25 support wire 17 in the interior of cavity 11. FIG. 3 is a pardal cross-section of ~e molded plug 29 ~huwi~g the wire 17 s~ e~l therein and su~w~d by bl~de 24.
~ FIG. 4 there is shown a par~al cross-sechnn~l view of the same lQ ~ m~ l mold of FIG. 2, but with the positioning blad~ 23-25 retracted out of the mo' 1in~ cavity 11. In FIG. S t:here is shown a partial cross-section of ~hemolded plug 29 with the wire 17 sus~n-1pt~l in ~e hardened plastic and wi~ the ~7.~ g blades 23-2S removed, leaving cavi~ void 30. As noted above, void 30 can be filled by retrac~ng the blade p~ior to the packing por~on of the 15 iniection cycle, or the void 30 can ~e left unfllled by retrac~ng ~e blade after the end of ~e injection cycle and after the plas~c has hardened.
Al~ough ~e me~od and ay~ of the p~esent inven~on for pc~ innin~ non-rigid cc,~ b in ~e interior of molded ~l~lu~, is shown in FIGS. 1-5 in c~ inn wi~ molded ele~rical plugs, it will be a~ i to 20 persons of olJin~ skill in the injection mollling art ~at this method and a~p~dlus can be used for positioning ~ in ~e int~or of many o~er molded products, whether rigid or non-ngid. Thin blades or forks are ~d having ~e edge interior to ~e mold cavity colllouled to match the exterior surface of the c~l"~nc~t to be positioned. Such blades or forks can be used to 253 ~e~i~ly position a large number of enc~rs~ ed c~n.l~n~ wi~in ~e interior of molded plas~c products without d~alLing from the spirit or scope of ~is inven~don.
~ 4hhnllgh the technique d~ in co~ with FIGS. 1-5 san be used to position many S~ir~ ~ pes of C~ X wi~in the interior 30 molded products, it is also possible to make use of one or more of the enr~lll~t~i cnmrnPnt~ itself to assist in positioning a .liff~.e~ nr~rS~ t~d c~ r.~t Such and elrtt.n-led positioning techni~que is r~ o~d in FIG. 6-8 in co,llle-;lion with a ~ree-pronged, grounded molded elec~ica~ plug.
. _ . .
o ~ g WO 9~/00840 PCl/US91/04673 In FIG. 6 there is shown a ~livt; view, in par~al section, of a three-prorlg el~;Llieal plug ~l~rir2~çrl by inir~hon mol~ing techniques in aecolda~ce with ~e present il~v~lllion. The plug body 40 enr~psul~t~c the ~ee wires of ~e three-wsre line ~ord 41 as well as st~hili7ing lands for ground pin 42 S and power pins in~ tlin~ pin 43 and a second power pin, not visible in FIG. 6.The upper por~on of ground pin 42 has two channel-formitlg l:abs 44 and 45 used to assist in ~uling the el~1~ical wire 46 cn.~ ~i to power pin 43. Thin blades with a~lu~ lcl~ col~uurt;d upper edges ~re also used to assist in po~itioning wire 46 in other portions of the mbld ~vit~. The mold cavity is 10 shown in cross-s~tion in PIG. 7.
In FIG. 7, the two half molds 50 and S1 define a mold cavity 52 îL.,Ic;belween in which wire 46 is positioned in par~ by bladP~ 53 and ~4 and inpart by the upper por~on of ground pin 42, shown in perspective view in FIG. B.
The tabs 44 and 45 capture wire 46 to hold wire 46 in position during the 15 m~ing process. Since wire 46 is fully in~ tPIl, the contact by tabs 44 and 45 does not i~ r~.e wi~ the PhP~i~l circuit. A çrimpi~ land 56 is also ~chion~d on grou~d pin 42 to provide a pl2Ce to e~ ly alnd me~h~ni~11y connect ~e ground wire of line cord 41 to ~e ground pin 42.
It should be clear to ~ose skilled in ~e art that further 20 emho~limp~rts of ~e present invention may be made by ~ose sldlled in ~e art without d~ g from ~e tP~in~ of the presP~nt invention.
Claims (9)
1. An injection molding apparatus comprising at least two molding dies defining therebetween a molding cavity for the injection of molten plastic, at least one flat rigid blade extending through the outer surface of said cavity for positioning a component within the interior of said cavity, said blade having at least one thin edge thereof facing the interior of said cavity contoured to mate with and capture said component.
2. The injection molding apparatus according to claim 1 further comprising means for retracting said blade from said interior of said cavity.
3. The injection molding apparatus according to claim 1 wherein said cavity defines an electrical plug and said component comprises an electrical wire.
4. The injection molding apparatus according to claim 1 further comprising at least one rigid component to be encapsulated in the interior of said cavity, and means associated with said at least one rigid component for holding at least one non-rigid component in position in the interior of said cavity.
5. A method for encapsulating non-rigid components at precise positions in the interior of an injection molded product, said method comprising the steps of placing said non-rigid components in appropriate positions within a half mold for said product, inserting a plurality of thin blade-like positioning elements through the wall of said half mold to capture and position said non-rigid components, assembling said half mold with a mating half mold to form a substantially closed mold cavity, injecting molten plastic into said cavity, and removing said product from the interior of said mold cavity after said plastic has set.
6. The method according to claim 5 further including the step of retracting said blade-like positioning elements from the interior of said mold cavity.
7. The method according to claim 6 further including the step of retracting said blade-like positioning elements from the interior of said mold cavity just prior to a higher pressure packing portion of the injection cycle.
8. The method according to claim 7 further including the step of spring-loading said blade-like positioning elements with a spring force sufficiently great to retain said elements in the interior of said mold cavity during the initial portions of said injection cycle, but insufficient ot maintain said elements in the interior of said mold cavity during the packing portion of said injection cycle.
9. The method according to claim 6 further including the step of retracting said blade-like positioning elements from the interior of said mold cavity after said plastic has set up.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US551,381 | 1983-11-17 | ||
| US55138190A | 1990-07-09 | 1990-07-09 | |
| PCT/US1991/004673 WO1992000840A1 (en) | 1990-07-09 | 1991-07-01 | Insert molding for non-rigid encapsulated components |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2086518A1 true CA2086518A1 (en) | 1992-01-10 |
Family
ID=24201041
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002086518A Abandoned CA2086518A1 (en) | 1990-07-09 | 1991-07-01 | Insert molding for non-rigid encapsulated components |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0538375A4 (en) |
| JP (1) | JPH05507890A (en) |
| CA (1) | CA2086518A1 (en) |
| WO (1) | WO1992000840A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102529015A (en) * | 2012-01-16 | 2012-07-04 | 焦志红 | Method for bonding plastic product to leather product |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6071446A (en) * | 1997-08-29 | 2000-06-06 | Lear Automotive Dearborn, Inc | Method for centering wire harness in mold |
| FR2799879B1 (en) * | 1999-10-15 | 2002-01-04 | Siemens Automotive Sa | OVER-MOLDED CABLE HARNESS AND MANUFACTURING METHOD THEREOF |
| US6583762B2 (en) * | 2001-01-11 | 2003-06-24 | The Furukawa Electric Co., Ltd. | Chip antenna and method of manufacturing the same |
| US7931184B2 (en) | 2006-09-18 | 2011-04-26 | Spinduction Weld, Inc. | Apparatus for induction friction solid state welding |
| CN113085081A (en) * | 2021-03-31 | 2021-07-09 | 广州欣凯裕生物科技有限公司 | Injection molding cooling device for ETC panel production |
| WO2023013375A1 (en) * | 2021-08-06 | 2023-02-09 | 株式会社小糸製作所 | Method of manufacturing transparent plastic cover for vehicle |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL85473C (en) * | 1953-01-29 | |||
| FR1105275A (en) * | 1954-05-24 | 1955-11-29 | Molded socket outlet, of plastic | |
| GB1223877A (en) * | 1968-06-04 | 1971-03-03 | British Insulated Callenders | Improvements in or relating to the manufacture of cable couplings |
| GB1430579A (en) * | 1972-06-21 | 1976-03-31 | Gkn Sankey Ltd | |
| DE2628703C3 (en) * | 1976-06-25 | 1980-10-09 | Maschinen- Und Werkzeugbau Gmbh, 3563 Dautphetal | Arrangement and method for the production of profiles, in particular for windows and doors |
| JPS55121864A (en) * | 1979-03-14 | 1980-09-19 | Bolton Emerson | Rotary roddrotary push roll nip type covering device |
| US4470786A (en) * | 1981-07-28 | 1984-09-11 | Omron Tateisi Electronics Co. | Molding apparatus with retractable preform support pins |
| JPS5818223A (en) * | 1981-07-28 | 1983-02-02 | Omron Tateisi Electronics Co | Molding method |
| FR2543356B1 (en) * | 1983-03-25 | 1986-01-10 | Ceraver | METHOD AND DEVICE FOR MOLDING THE INSULATING COATING OF A LARGE ORGANIC INSULATOR |
| DE8622028U1 (en) * | 1986-08-16 | 1986-12-18 | Chemieschutz Gesellschaft für Säurebau mbH, 6140 Bensheim | Spacers for centering cores to be coated in the injection molding process in the mold cavity |
| JP2816732B2 (en) * | 1989-12-27 | 1998-10-27 | 住友電装株式会社 | Method of manufacturing probe for brake pad wear detection device |
-
1991
- 1991-07-01 WO PCT/US1991/004673 patent/WO1992000840A1/en not_active Application Discontinuation
- 1991-07-01 JP JP91512307A patent/JPH05507890A/en active Pending
- 1991-07-01 EP EP19910913449 patent/EP0538375A4/en not_active Withdrawn
- 1991-07-01 CA CA002086518A patent/CA2086518A1/en not_active Abandoned
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102529015A (en) * | 2012-01-16 | 2012-07-04 | 焦志红 | Method for bonding plastic product to leather product |
Also Published As
| Publication number | Publication date |
|---|---|
| WO1992000840A1 (en) | 1992-01-23 |
| JPH05507890A (en) | 1993-11-11 |
| EP0538375A1 (en) | 1993-04-28 |
| EP0538375A4 (en) | 1993-10-13 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |