CA1270359A - Apparatus for making pilfer-proof cap - Google Patents

Abstract

ABSTRACT

A mold for making a plastic pilfer-proof cap having frangible members connecting the pilfer-proof ring to the skirt of the cap and in axial alignment therewith and having sufficient strength to permit flexing under axial compression but to break when flexed while under tension. The mold includes inner male and outer female members for forming the mold therebetween.
The female member includes radially movable rams for engaging the male member to define the mold space for forming the frangible members of the cap.

Description

~1--BACKGROUND OF THE INVENTION

The present inventlon relates to a mold for making an improved cap for use with co~tainers whereby removal of th~ cap leaves behind a telltale ring member.
There are presently available many pilfer-proof closure or cap constructions of this type. Tamper evident container caps are widely used to demonstrate to the final consumer that the contents of a container have not been contaminated or adulterated subsequent to the time the cap was initi~lly secured to the container.

Generally, pilfer proof cap~ are con~tructed with a~
threaded skirt portion extending downwardly fro~ the top wall of the cap and a pilfer-proof ring membe~ a~tached to the lower end af the 5kirt. The ring 1~ attached by frangible members which break upon unthreading o~ the cap from the container due ~o engagement of the ring ~ember below a prot~uding led~e or shoulder on ~h~ cont~iner. ~or~
particularly, the r~ng in~lude~ a~ in3id~ annular rib which, in ~3e on the container, i~ loc~t~d below a cooperating outwardly extending rib on th~ n~ck of th@ container. As ~he cap i~ twi3ted off the cont~lner, contac~ between the outside rib on he con~ain~r neck and the inYide rib on the ~eparable ri~g o~ the cap breaks ~he previously mentioned frangible mèmb~, s~p~rating the ring ~rom the rem~inder of the cap.
~ith met~l closure~, the for~ation o~ the pilfer-prooE ring i~ typically effected aft~r the closure has been placed onto ths container. ~ose parti~ularly, th~ pi}fer-proof ring is ecured under a coop~rating ~hould~r on the container neck by a rolling op~ration. Nith the advent of mold~d pla~Pic caps, the pilfer-proof ring por~io~ of the cap ~ .

, ' ':~,: ' ' .''' ':
,' ' ;' :

~703~ -2-is preformed a~ part of th~ initial molding of the cap. This p~e~ent~ some problems with respect to structuring the pilfer-proof ring and fr~ngible members so that the cap can be threaded onto the container without break~n~ the fr~ngible members. If breakage occu~s, the ring i8 o~viou~ly of no value for use as an indicator of tampering with or removal of the closure.
The molding of plastic cap with pilfer-proof rings also presents some problems. The molding operation requires an internal die member for shaping the inter~al ~urface of ~he cap. This die member has external threads ju~t like the bottle with which ~he cap is to be u3ed. Thi-~ thread structure and other portion~ of the die required for formins the pilfer-proof ring can interfere with removal of the cap by obstructing the ring and cau~in~ it to break away just a~
if the cap were being unthreaded fro~ the contain~r.
At~empts have been made to design plastic caps to overcome the problems as~ociated with molding and applying the cap to the container. My prior pat~nt, No. 4,322,012 di~close~ a mold~d plastic pilfer-proof cap in which the pilfer-proof ring i9 attached to the ~kirt by fr~ngible member-~ and constructed inter~lly with locking member having the appropriate camming surface to perm~t ~hreading of the cap to the container wi~hout breaking of the frangikle member~. Molding o~ ehiq type of cap ~on~truction, however, ~ypic~lly requir2s a collapsible in~er die m~ber.
U.S. Patent NoO 4,147,268 al~o di3clo~e~ a molded plastic pilfer-proof cap. In thi~ cap the pilfer-proof ring i~ co~tructed with internally pro~ruding locking members 30 which extend a~ an angle ~o a~ to p~r~it the cap to be removed fro~ the internal die member by unthreading. This same structure permits the cap to ~e threade~ onto .h~
container. In addition, the locking ~em~r~ ~ro provided with camming surface~ to per~iS ~liding ov~r ~he locking .: .
. .:
:,: ,:..
, . .

. .

, 1~7~35~ -3-shoulder o~ the cont~in~r a5 the cap i~ f~lly threaded onto the container.

~ N
The pilfer-proof cap constructed in accordance with the teachings of co-pending parent Canadian Patent Application No. 474,033, filed February 11, 1985 includes a pll~er-proo~ ring which is structured and connected to the skirt portion of the cap in such a manner as to readily permit its removal from the internal molding die and subsequent attachment to the container. More particularly, the pilfer- -proof ring is con~tructed with an inwardly protruding locking means, in the for~ of an annular rib~ for engagement under a cooperating rib or ~houlder on the ne~k of the container to 15 which it is applied. The frangi~le m~an4 which connects the pilfer-proof ring to the lower end of the ~irt portion of the cap i~ axially aligned with both the ~kirt and the pilfer proof ring.
Th~ moldl for formirig thi~ cap ~o~pri~e~ a female 20 member forming a ~ocket ~rl an oriPice ~or conduc~ng plastic material into the ~ocket, and a male ~e~b~ ir,cluding a core as~embly axially extendin~ inl:o the socket to form a mold ca~7ity wlth the female member. The outer 3urface o~ the male member ha~ a f ir~ annula~ reces~ fo~ l~onDing the radially 25 inw~r~ly extendiny rib on th~ tampe~ indi~ating ring and a ~econd thre~ded r~ceg~ for forming the in~ern~J. thsead~ on the cap. The ~e~al~ mem~er of the mold inc~lud2~ an upper as~e~bly tha~ or~a~ an upper portion of th~ soc~e~, and a lower a~e~bly baving a plurality of c~ms th~t ~orm a lower 30 po~tion of the 3ccket. ~a~h o~ these ca~ ha~ a radisl protru~ion engagi:ng th~ core a~s~mbly o~ the male ~ember at circumfe~en~lally cpac@d interval~ ~o or~ an a~nnular recess in the cap axially ~ep~rating th~ t portion ~ro~ the ring and circuhlfeaentially separating the fr~ngible ~e~b~r~ which 35 connect the ring to the skirt.

. .

':
.: :

~ 3~ ~4~

To remove the cap from the mold, the female member of the mold is removed from the cap, and then the ~ap itself is removed from the ~ale member of the mold. The female member is re~oved from the cap by moving th~ upper a sembly of the female member axially and the cam~ thereof radially away from the cap. Preferably, the cap i~ shrunk onto the male member to develop ~ space between th~ cap and the ~emale member of the mold prior to removing the female member from the cap. Developing this space between the cap and the female member of the mold eliminate3 any tendency of the female member to rub against the c~p or to tear or ~o pull the cap apart as that femal~ member i3 removed from ~.he cap.
This permi~-s the molding of caps wherein the outer wall urface of the ~kirt portion i~ at a right angle to the top of the cap rather than tapered outward}y from that top.
Removal of the cap from the mal~ memb~r i~
accomplished, in part, by pu~hing on the bottom edge of the ring of the cap in an upward direction. This force3 the inside rib of the ring out o~ the annular rec~s of the male me~ber in which that rib is formed.
The cap may be re~oved fro~ the mold without exertin~ tensile forceq on the frangible member~ of the cap, The axial alignment of the ~ra~gibl~ ~ember~ with the skirt and ring together with the~r thickne~ provide ~nough axial rigidity to pr~v~nt the pil~er-proo~ ring f rom u~duly flexing relative to th~ ~kirt portion o the cap during ~hi3 removal operation. Th~ en~ire wall s~ructure o~ ehe eap ~i~ply exp~D~ ~oro or les~ as an integral unit. Thu~, beeaking of th~ fr~gible m@~bers i~ avoided. I~ thl~ way, the frangible me~b~r~ m~y b~ de~igned to break readily when any appreciable ten~ile ~orce i~ applied to tho~e me~ber , in3urin~ ~ha~ the tamper indica~ing ring of the c~p will break aw~y from the skirt of that cap whe~ th~ cap i~ re~o~ed fro~ ~ container.
. This s~me f~ture i~ o u~ful during attaching 3~ the cap to the contain~r. A~ thQ ~ap i~ thre~dsd down onto ~27~ s-the neck of the containeri the bottom of th~ pilf~r-proof ring engage9 against the threads and createY an axial compression of the ring toward the overlying ~kirt. This holdq the ring, frangible members and skirt togeth~r in compres~ion a an inte9ral unit and permit~ them to expand without such severe flexin~ o the ring relative to the skirt which would cause breaking of th~ frangible member~. ~he b~ttom surface of the protruding rib locking mean~ on the pilfer-proof ring i~ also st~uctured to readily permit this expansion of the ring over th~ threaded portion of the neck of the container.

~ .
Fig. 1 is an enlarged cross-section view of the cap made by the present inventio~ showing generally in schematic form a part of the internal ~old structure on which it is molded and with the cap partially removed therefrom; and Fig. 2 is an enlarged cross-sectional view, partly broken away, showing the cap a~ attached to a container.
F~g~ 3 i~ an enlarged front view of a cap having int~rnal ~op ~aling mem~er~ formQd i~ a mold constructed in accordance with thi i~vention.
Fig. 4 i~ an axial cro~-sectionsl view of the cap shown i~ Fig. 3, tak~n ~long line 4-~ thereof, showing the cap ~cur~d ~o ~ cont~iner.
Fig. 5 iR ~ front cross-~ection~l vi~ through the mold used to for~ the cap shown in Fig~. 3 ~nd 4, showing the mold in a clo~ed po~tio~.
Pig. 6 is ~ ~ide cro~ tion~l Yiew through the mold shown in ~ig. 5, ~howing the mold in an open po3ition.
Pig. ~ i~ a top view sho~ing the ~m4 of the female - member of th0 mold illu3t~ated in F$gs~ 5 and 6 3~

~17~33~ 6-FigO a i~ a~ enlarged view of a portio~ of FigO 5 showing the mold ca~ity in which the cap is formed and the immediately adjacent parts of the mold in gr~ter detail.
Fig5. 9 and 10 are qimilar to Plg~ 8 ~nd depict in sequential order different stages of the remoYal of the cap from the mold.
Fig. 11 is a simplified view of a molding apparatus casrying a plurality of molds of the type shown in Figs, 5 and 6.
~ D EMBODIMENT

With reference to Figs 1 and 2 the cap produced by the present invention generally incl~des a top wall 1, a depending side wall or skirt 2 and th~ -improved pilfer-proof ring 3 attached to the bottom end of the skirt. The in~ernal wall surface of the skirt includes a threaded portion 4 adapted to mate with complementary threads 5 on the neck 6 of a container such as shown in Fig. 2. The cap is fahricated from a relatively rigid plastic su~h as polypropylene.

The p~lfer proof ring 3 is connected to the skirt portion of the c~p by separ~te ~rangible ~e~ber~ 7 and include3 a r~di~lly inwardly extending lo~king ~e2n~ in ~he form of an inwardly direc~ed protru~ion or rib a extending 25 ~olapletely around the inn~r periphery of the ring. The locking meaf2~ i3 adapted to ~lide over a rib or ~houlder 9 on the out3id~ ~urfac:e o~ ~he ~ont~ine~ neck a~ ~he cap i9 threaded onto the coataine~. With thQ c:~p fully threaded on~co the container, the lo~ki~sg mean~ i po~itioned under the 30 ~houlder 9 so that upon unthre~ding of ~he cap, upward movement of ~h~ pil~er-proof ring ~ill be blos:ked therebyO
The fr~ngible melaber~ 7 connectiFIg the rin~ to the ~kirt are - construoted so th~t they will break aw~y a~ th~ ring engages the ~houlder 9. This puts th~ ~embe~ 7 in t~n~on and at the same tim~ cau~e~ the ring to exp~nd ou~wardly, in turn, ~2'~59 ~7-c~using flexing of ~he members. The combined pulling and flexing of the frangible members cau5e~ their breaking. More particularly, as the cap is ~nthreaded fro~ the bottle neck 6, the skirt 2 is moved upward and pull~ th~ ring 3 upward therewith. Upward move~ent of the rin~ 3 is re isted ho~ever by contact between the rib 8 and the shoulder 9. This contact and resist~nce, first, develop~s tensile for~s on the frangible members 7 connecting the ring 3 to the skirt 2 and second, forces the rib 8 and tho~e frangible members 10 outwardly. The combination of the ten~ile force~ and the outward flexing of the frangible member~ 7 break~ the members, separa~ing ~he ring 3 froM th~ ~kirt 2. The skirt 2 is then completely unthreaded fro~ the bottle neck 6, opening the bottle and leaving the ring 3 behina.
~n accordance with the teachings of the aforesaid parent application, the frangible members 7 are axially aligned with both the skirt and ring portions of the cap adjacent the outside surface of the skirt. They also are constructed with a sufficient cross-sectional dimen~ion so as to provide axial 20 rigidity between the skirt and the ring upon subjecting the ring tu an axial compres~ive force directed tow~rd the skirt.
This con~truction facilitates removal o~ the molded cap f rom the intern~l die me~ber 10 on ~h~ch it i~ formed. Removal is effected by puqhing the ~ap of the intern~l die member by a 25 stripp~r ring 10 ' . The pu~hlns~ force is exerted against the bottom of the p~lfer-proof ring a~ indicated in Fig. 1. Due to éhe axial alig~l~ent of the f rangibl~ ~ember~ 7 with both the ~ing and skirt and also due to the c~o~ ction thickne~s of the ~rangible ~mb~r~, the forc:e exerted on the 30 bottom of the ring put ~che me~bers in compre ~ion. The pu~hing force i~ directed in a g~nerally ~raigh~ line through the ring~ frangibl~ ~e~bers and ~kirt q ith the res~lt tha~c ~here i little bending moment creatg~d.
The cap generally expands radially outw~rdly as it is removed from the internal die ~e~r 10. P~rtlal re~oval ~.27~35i9 -8 -of ~he cap f rom the die member is shown in Pi~. 1. There it is seen that the internal thread 4 of the cap a3 it engages against the external thread 11 on the die ~ember 10 effects a camming of the skirt portion of the cap radially ou wardly of ~he die member. The skirt actually expands a~ it i cammed over the die threads. At the 5ame time the upper surface 12 of the locking protrusion 8 on the pi:Lfer-peoof ring engages agains~ the complementary shaped wall surface 13 of the internal die member. Thi~ engagement effect~ a camming of the ri~g in a radially outwardly direction to cause it to expand at the same time the ~kirt i~ being cammed and expanded radially outwardly.
Due to the location of ~he frangible members and the rigidity provided by th~i~ cross-~ectional thickness, the skir~ and ring expand more or le~s a~ an in~egral unit without flexinq of the ring rela~ive to the qkirt to an extent which would cause breaking of the frangible ~nembers.
Removal of the molded cap fro~ the intern~l di~ member can therefore be accomplished w~th a si~ple puqhing operation.
20 Com~licated collapsible m~le die ~tructure i~ not required.
In the preferred embo~imPnt of the cap the inwardly directed protrusion 8 of the locking portio~ of the pilfer-proof rinq h~ an axial cro3~-~ection which i~ generally conical in ~hape. That i., thl~ cross-section of protru~ion ~ ha~ a ~hap~ g~nerally ~imilar to theshap~ of an axial cro~-section of a ~olid cone. The upper surfa~ 12 of th~ protru~ion i~ a ~tralght 3urface; and as ~how~ in Fig. 2, ehis.~urface i d~po ed at an an~le about eq~l to the angle at which ~he ~houlder 9 of ~he con~ainer exg~nd~ The bo~to~ ~urfac~ of the protru~ion ha3 an axially downw~rdly faCiR9 convex ~urface 1~. Th~ 3urface3 fa~ilita~e connection of the cap to th~ con~iner and ret@ntion of th~ ring on the con~ain~r upon removal of the cap~ ~ore particularly, ~he fl~t ~r~ce 12 eng~gex again~t the complementary shaped sur~ace o~ the ~houlder 9 whereby . . , ~, . ~ .
': ;'~' .
.' :
., :. . . : ' ~a.2~33~ _9_ axial unthreading of the cap p~duce~ a pulling effect on the ring and the frangi~le member~ to put them in tension. The tensioning or pulling on the frangible mem~ers to9ether with their simultaneou~ flexing a the ring is cam~ed outwardly over the shoulder 9 of the bottle c~uses the frangible members to break.
~ he convex shape of the bottom surface 14 of the protrusion 8 of the pilfer-proof ring assist~ in camming the ring over the threadR 5 of the ~ontainer neck as the cap is threaded onto the container. A~ain9 engayement of the bottom of the ring against the thread produce~ ~om~ compre~ive orce through the ring, frangible ~mber~ and skirt coupling these members together a~ an integral unit to thereby prevent undue flexing of the ring relative to the skirt. And without any ~imultaneou~ pulling of the frangible ~e~ber~ a occurs upon removing the cap from the cont~iner, they do not break.
As shown in Fig3. 1 and 2, th~ rad~lly inwardly mo t surface of the protru~ion 8 of the pil~er-proof ring is provided with multiple circum~erentially ~paced area 15 dispsced radially outwardly o the remainder of this surface.
Although the~e area~ 15 are loc~ted radially outwardly of the innermost extent o~ the protru$ion~ they will, nevertheless, be located u~der the shoulder 9 of the container when the cap i~ fully thr~aded onto the ~onta~ner. Thi~ i~ shown in Fig.

2. Accordingly, engagement of thQ upper surface 12 of the protru~ion wlth ~he ~houlder 9 occur at all po$nt~ around the pilfer-proof ringO
In the preferred embodiment, the circumferentially spa~ ar~as are curved to define radially Lnwardly facing 30 cur~ted portior~ and they are e~enly ~paeed ~rom e~ch other.
~oget~er they extend over one-half of the inner periphery of the protru~ion 8. There are eight uch are~s spaced ~bout the in~ernal periphery and e~c:h are~ cov~r~ ~ circumf~rential distanee of about 22 1/2-. The remaind~r of th~ Lnner 35 ~urface of the protru~ion 8 is formed a~ flat~ 16. The e ~ ~ 7~ t~-flats define chordal portion , spaced between ~he curved portion3 of the protrusion, and are aligned with the frangible member~ 7.
Figs. 5 through 10 illustrate in detail the pre~e~ly preferred continuation of a mold 50 for forming the cap of Fi~s. 3 and 4. Mold 50 comprise!s a female member 52 and a ~ale member 54. The female membe!r 52 form~ a socket 56 and an orifice 58 for conducting plasti.c material, such a polypropylene, into tha~ socket. More specifically, a cavity plate 60 of female member 52 forms a central opening 62 and a mold piece 64, which for~s an upp~r ~srtion of the socket 56, is dispo~ed thereinO A clamp plate 66 extend~ over the mold piece 64 and over the cavity plate 60 and is bolted to the cavity plate to clamp the mold pieee withln the central 15 opening 62. A material conduit 70 i~ ~ecured to the clamp plate 66 and forms an upper portion of the orifice 5û. One or more water paqsages 72 extend through fem~l~ member 52, adjacent the socket S6, to conduct water through the female member of ~he mold 50 to cool ma~erial fed into the socket 20 56.
A plurality of cam~ 74 tog~th~r form a lower portion of the socket 5S, and the e cam3 includ~ radial projection~ 76 hat engage circumf~rerltially ~paced section of male member S2, specif~cally a core a~embly 7a thereof, to form the annular rec~ of the cap betweerl frangibl~
m~mber~ 7 6 ~ch~reof . The ca~ 74 rest on and 2re supported by the male m~b~r 54 ~pecific~lly a op ur~ace 80 ~chereof, for 31idinq ~nove~nt b~tween a clo~ed po~i~ion, shown in Fig 5, wh~ein the ca~ engage core a~bly 78, a.nd an op~n 30 po~it~on~ ~hown in Fig S, wh~rein the ca~ are spa~qed f rom the core a~sem~ly ~o facilitate removi~q cap ~rom the ~nold cavity in which the cap i~ formed.
A ~pring 82 is provid~d to urgç~ th~ ca~s 74 f rom their clo~ed poelition to their open po~ition. Irl particular, 35 the ~pring ~2 i~ a conventional clip spring with a circular .. ..

..' ~' ~Z70359 ~

shape and i~ positioned against radially inwardly facinq surface~ of the cams 74, ur~ing those cam~ radially ou~wardly, away from the eore a5sembly 7B. A groove is formed in the5e radially inwardly facing surfac2~ of the ca~s 74 to hold the spring 82. A plur~lity o screw~ or bolts 84 are threaded into the top surface 80 of male m~mber S4 to limit outward movement of the cams 741 Means other than springs 82 may be used to move cams 74 ~o their open positions, For instance a plurality of pin~ may be connected to the cavity plate 60 and ~lant downwardly outwardly into sockets formed in the cam , whereby the pin~ would push the cams outwardly when the cavity plate 60 i~ rai~ed and push the cams 74 inwardly when the cavity plat~ is lowered. Also, means 86 (illustrated in Fig. 7) such as L-~haped pins, rails, pin3, or similar device~ 0ay be secured to the ~urface ~0 to guide movement of th~ cam~ 74 between their open and closed positions and to hold those cams against upward axial movement away from the surface ~0.
With the embodiment o~ mold 50 illustrated in the drawing~, the cam~ 74 are moved from their open po~ition to their clo~ed po~ition and ~r~ rele~s~bly held in the latter position by mean~ of engagem~nt between cooperating surfaces of the cam~ and the cavity pl~te 60. ~or~ 3peciically, the ca~ 74 have upper urfAces 90 th~ ~lant up~ardly radially inwardly, and cavity plate 60 ha~ ~ lower sur~ace 92 directly abcve he upper surfaGe~ 90 of the ca~ and that also slants upwa~dly radially inwardly. A~ cavity plate 60 ~ove~
down~rdly ~ro~ itB open po~ition, 3how~ in Fig. 6, to its clo~ed po~ition, shown in Pig. 3, the ~urf~c~ 92 of the c vity pl~te contacS~ the ~urface~ 90 o the ca~ 74 and forces tho~e ca~ radlally inw~rdly to th2ir clo~d position.
As the cavity plate 60 is h~ld in it~ ~lo~ed po~i~ion~ the surface 92 hold3 he cam~ 74 in th~ir clo-q~ po~ition.
With particular referen~e to F~g. 7, in~ide edges of the radial p~o~rusion~ 76 of the ca~ 7~ h~ plurality ~ ~'7~ ~9 ol2 of circumferentially spaced groove~ 94~ When cam 74 are in their clo-~ed po5ition, the grooves 94 form opening~ extending between the cam5 and the core a~sembly 78. The frangible member~ 7 of the cap are formed in those openingi. Also, while the embodi~ent of mold 50 shown iQ th~ drawings includes four cams 74, the msld may he provid~d with fewer or more cam~, ~or example two, ~ix, or eight, wi hout departing from the scope of the present invention~
As outlined above, cavity plate 60, mold piece 64, clamp plate 66, and material conduit 70 comprise an upper assembly of female member 52 of mold 50; and cam~ 74, pring 82, and guide mean~ 86 comprise a lower a~embly of the female member.
A support a~embly 96 of male me~ber 54 provides a base of support for the female member 52 and the other parts of ~he male member of the mold 50. Plates 9~ and 100 of the aRsembly 96 are generally horizontal and p~rallel, and these plates form generally aligned central op~nings 102 and 104 respectively. Spacer block~ 106 and 110 of the ~upport assembly 96 extend between th~ plate~ 9~ and lO0~ acro~s the bottom left and right ide3 of th* ~old 50. T~e variou-~plate~ and block~ o~ the ~upport assembly 96 are ~ecured ~ogether ~y a plur~lity of bolt~ to for~ ~ rigid, unitary assem~ly~
Wi~h re~p~t to the core a~e~bly 78 of ~ale ~ember 54, when ~h~ ~old 50 i~ ~n th~ clo~e~ or ~p ~ormi~g po~ition, ~how~ in ~ig. S, the core ~embly 78 axiall~
ex~ended into the so~ket 56 to form, with th~ ~emale member 52, th~ parkicular mold cavity in which th~ cap i~ formed.
Mor~ 3pe~1fic~11y, an outer core piece 112 re~t-~ on the upper plat~ ga o the support a4sembly 96 and extond~a a~ially upwardly ther~fro~. Tne upper po~ ion of ~h~ ou~er core pie~e 112 extend~ into the ~ocket 56 o~ the fe~le member 52 and, during for~tion of cap, form~ th~ interior o~ he sides and a portion of th~ interior of th~ top o~ th~ ~ap. The . .
,. ~ ..
.., ~, :
' ~ . .
: .

~ ~ ~03 ~ -13-upper portion of th~ outer core piece 112 includes a first rece~Y 114 which is us~d ~o for~ the rib 8 on the ~ing of the cap and a second annular reces~ 116 to fer~ th~ thread~ 4 of the cap.
S The ooter core piece 112 is axially held in place by means of a retainer sleeve 118 and a retainer ring 120.
The bottom portion of the ou~er core piece t12 includes a radially outwardly extending shoulder, ~nd the retainer sleeve 118 in~ludes a downwardly facing radial surface that extend~ direc~ly ove~ tha~ shoulder of th~ owter core member.
In turn, the lower portion of the retainer ~l~eve 118 includes a radially outwardly extending shoulder, and the retainer ring 120 includes a downwardly facing radial surface tha~ extend3 directly over that ~houlder of the retainer-sleeve. The retainer ring 120 it~elf i~ Recur~ly bolted tothe top plate 9~ o~ support a ~embly 96.
The interior of the outer core piece 112 forms an axial through bore, and an inner core piece 104 extend~
therein and i~ supported ~or axial moYement relative to the outer core piece. The upper portion~ oP th~ inner core piece 122 and the through bore of outer cor~ piece 112 are both flared out. In the closed po~ition shown in Pig. S, the top su~face o~ the ~nne~ core piec~ 122 i~ substantially coplanar with the top surf~ce of the ou~er cor~ piece 112 and, during formation of th~ c~p, forms the m~or portion of the interior ~urface o~ th~ top of the cap. The outer and inner core pie~es lt2 and 122 togeth~ for~ a top axial rece~s 124 in which top annular 3ealing me~ber 26 of th~ cap i~ formed, and th~ r core piece 122 forms a top axi~lly slanted recess 126 ~ w~ich the top annular seal$n~ me~ber 30 of th~ cap is formed. Preferab~y, the inner core piece 122 includes a sepasable upper insert that i~ in a tight pre~ure fit with the main body of the inn~r core piec~, and the~ two pieces in combination for~ the rece~ 126.

.. ...
.,, . ~ .
: . , ~7~35~ - t4~

The inner core piece 122 also defines an axial ~hrough bore and a knockout pin 130 axially extends therein and i~ s~pported for axial movement relative to the inner core piece. The knockout pin 130 9enerally i~ a 3mooth, ~olid cylinderl with a s~all annular shoulder 132 extending outward from the bottom of the pin. Wh~en the mold 50 is in the closed position shown in Fig. 5, the top surface of the knockout pin 130 is coplanar with the tlDp urface of the inner core piece 122, and the knockout pin extends downwardly therefrom, through the inner core member, to a position below the bottom thereof, One or more water pa~sage~ 134 extend through the kno~kout pin 130 to conduct water therethrough, adjacent the mold cavity in whieh the cap i~ for~ed, to cool ma~erial fed into the mold cavity.
t5 A ~tripping assembly 136 i~ provided to pu3h cap axially off core a33embly 73. Thc ~tripp~ng as~embly 136 includes a ring 138 and a plate 140. Ring 138 extend~ around core assembly 78, below the mold cavity in which the cap is formed, to pu~h th~ botto~ of the ~ap o~f th~ ~ore aqsembly, and th~ rin~ 138 re~t3 directly on plate 140 ~o that upward moveme~t of the plate 140 moves ~he ring 138 upwardly. When the mold SO i~ in the closed position ~hown in Plg. 5, and upper portion of ring 138 tightly fit~ around a~ intermediate portion of outer core pie~e 112 and form~ th~ bot~om of the mold cavity in which cap iQ formed. An out~r portion of ring 138 form~ a radially outwardly ~xtending shoulder 142 ~hat rent~ on th~ top ~urface 80 of the plate 140. Thi~
eng~m~nt b~tween ~houlder 142 and surface 80 force ring 138 ~wa~d with plat~ 140. A lower portion o ring 138 ax~lly extend~ into a cen~ral opening 146 of plate 140, in a close radial fit ther~with, to hold th~ ri~g 138 ~ecurely in plac~, around core ~s~embly 78.
The plate 140 direc~ly re~t~ on th~ top support plates 98 whe~ th~ mold 50 is in the ~lwed po~ition shown in Fig, S. When cavity plat~ 60 a~d mold piece 64 o~ ~emale , :'; ' :;: ..: ,... ..
`.~ ", ...... , .. ,, .: :
:: . .

~ 9 -15~

member 52 are moved upward away from their clQRed po~ition shown in Fig. 5, the plate 140 is free to move upward away fro~ support plate 98 for a limited distanc~, and means such as springs 150 are provided to move the plat@ 140 upward relative to that support plate. More particul~rly, the plate 140 and support plate 98 form a plurality of rece~3es, and springs 150, which may be conv~ntional coil prings, are located in ~hese reces~es, urging plate~ 140 and 98 axially apart. of course, means other than conventional coil springs, for example air or hydraulic cylinderY, may be used to move the plate 140 away fro~ the support plate 98. Means such as bolts 152 (only one is shown in the drawings), may be used to guide axial movement of the plate t40 away rom and towards support plate 98 and to limit axial movement of the t5 plate 140 away from that support plate.
A first ejector as~embly t54 i9 lo~ated between plate~ 92, 94, 96 and 100, and engages the inner core piece 122 to push that core piece upward to h~lp pu~h the cap 10 o~f the outer core pie~e 112. Plates 156 and 158 of the ejector a~sembly 154 orm central opening~, wi~h the inner core member 122 extending through tho~e o~en~ng~ n a close radial fit with the surface~ thereofc 8Olts 152 extend between the pl~t~ 156 and the plate t40 to moYe th~ form~r plate axially upward with the latter plat~, and bolt~ 160 ~5 (only one i5 ho~n i~ th~ drawings) conne~t the pl~te 158 to the plate 156 for unitary axial movement. A retainer ~ing 162, which ~ay b~ a conventional snap ring, i~ secured within an aDnul~ groov~ formed in the lower portlon of th~ outside surac~ of the in~erior core memb@r 122, extend3 ~adially

3~ outw~r~ there~ro~, and i3 tightly captured betwe~n the plates 156 an 158. In ~hi~ manner, upward ~ove~ent of the plate 158 force the ring 162, and thus the cor~ me~ber 12~, upward th~rewith; while downward mo~emen~ of th~ plat~ 156 forces the ring 162, and h~nce the core me~ber 122, downw~rd therewith.

...

:-~ :. .
`' '., :
~ ' ' '; .
... .

~ ~ 7~ 16-A second ejector assembly 164 is located directly below the first eje~or assembly 154 and enqages the knockout pin 130 to push that pin upward. A plat~ 166 of the second ejector assembl~ 164 extend5 dlrectly below and contacts the bottom of the knockout pin 130. Another plate 168 of the ejector assembly 164 i~ located above the plate 166, is connected thereto by ~eans of bolt 170 (only one is ~hown in the drawings~, and form-~ a central axial opening through which the knockout pin 130 extends.
The plate 16B form3 a downwardly facing ~adial surf~ce that extends directly over the ~houlder 132 of the ~nockout pin 130. with ~his arrangement, upward ~ovement of the plate 166 forces the knockout pin t30 upward therewi~h via the direct contact between the plate 166 and the knockout pin; while downward movement o~ the plate 166 force~ the knockout pin downwa~d therewith via the ~olt~ 170, the plate 168, and the shoulder 132. The plate 166, in turn, i9 connected to a pair of knockout bars 174 by connecting pins 176 for uni~ary upward and downward ~ovement therewith.
Bolt~ 178 (only on~ i~ shown in the drawing~) are secured to the plate 158 of th~ fir~t ejector a ~e~bly 154 and extend through the plate~ 166 ~nd 1~8 of the necond e~ec~or a ~e~ly 164 ts guide axial move~ent o~ the second ejec~or a~sembly within the mold 50. Th~ bolt~ 178 al~o 3erve to pull the fir t e~ector a~se~bly 154 downwar~ wi~h the ~econd ~jector a~e~kly 164 aft~r the form~ a3~e~bly ha~ ~oved a p~e-set, limi~ed distance downward relati~ to the lattee as~ ly.
In operation, the mold 50 i~ conn~cted to a molding appar~u~ 180~ ~chematically ~hown i~ Fig. ll, tha~ first, support~ the mold 50, and ~econd, operate~ ~o rai~e and to lower the knockout ~ar~ 174, th~ upp~r a~ bly of the female member 52, and the s~ripping a~e~bly 136 o~ ~h~ m~le ~ember 54. A~ a pra~tical m~tter, i~ w~ or~ally b~ ~ore economi~al to connec~ a multi~ude of t.h~ ~ol~ 50 to a ~inqle molding apparatu~.

:: ~.,.

~ 5~ -17-If this is done, it sh~uld be observed, it i~ not necessary to provide each mold 50 with separate mean~ for rai5ing the cap, stripper mechani~m 13C of the mold. For in5tance, a moldi~g apparatu3 th~t carries twenty or thirty molds 50 may use two, ~our, or ~ix air cylinder~
182 to raise the cap ~tripper mechanism~ of he mold With reference to Fig S, to ~.'orm the container cap, plas~ic m~terial, such a polypropylene~ i~ injected ~h~ough the orifice 158 to fill the ~old caYity formed betw~en the female and m~le me~ber~ 52 and 54, Cooling water i~
coztducted through the water pa~age~ 7? and t 3~ of the mold 50, and the plastic material in the ~old cavity cool~ and harden~. This cooling o~ female and male me~er~ 52 and 54 -- in particular, the rate at which the cooling water is 15 conducted ~hrough tho~e members -- is controlled ~o l:hat the temperature of the portion o the male member ad~acent the cap is maintained below the temp~rature of th~ portion o~ the female member ad~acent the capO For exa¢lpl~, the portion of the mal~ me~b@r 52 adjacent t:he ~old ~avity in which the cap 20 is formed may be ~aintained a'c 400-F while the portion of the female member 54 ad~cent that mold cavity may be maintained at 600~. Becau~e of ~h~ te~nperature differenc~ a3 the pla~tic ~terial irl the mold cavi~y harden~, the ~ate!rial in the mold c~v~ty shrln3c~ o~o q~he ~le ~ember 52, ~pecifically the core ag~m~ly 78 th~r~of, and ~ ~pace d~v~lo~ betw~en the cap and the fe~lc me~b~r 54, ~pecifically ~old pi~ce 64 thereoO
Onc~ the ~ap hardens, the female member 54 iq re~ov~ fro~ the e~p. With r~erence to ~lgure~ 4 and 9, th~ ~9 done by ~ovl~g the upper a~mbly o~ he female memb~r 54 upwardly axially and th~ lower a~e~bly of the - feMale m~mb~ 54 rad~ally aw2y f~om th~ c~pO Thl~ 1s done by expandin~ cylinde~ 184 of molding apparatu8 180, ~hich raises plate 186 thereof, which in turn, raises clamp plate 66, cavity plate 60, and mold piece 64 of mold 50. Since the cams 74 are ... ~: :
.. .. .

35~ -I 8-releasably hela in their closed po~ition by th~ pressure exerted on the cams by the caviSy pl~te 60, as soon as the ca~ity plate i~ ~oYed away from the cam~, tho~e cam~
automatically lide outward along the ~urPace 80, away from the cap.
It qhould be observed that, becau3e of the space developed between the mold piec~ 6~ and the cap, that ~old piece does not rub again~t or tend to tear or to pull the cap apart a~ the upp~r assembly i moved away from the ~ap.
This, of courser ~acilitate moving the ~old pi~ce 64 away from the oap and en~ures that the mvld pie~e do~ no weaken or otherwi~e deleteriously affect the container c~p a~ ~he mold piece move3 away therefrom. Thi~ perm~ts the ~olding of cap wherein the outer wall surface of the kirt portion of the cap i~ at a right angle to the top of the cap rather ~han tapered outwardly downwardly ther~rom.
Next, the cap i~ removed f rorA the male member 54 .
Thls is done through coordinated move~ent of the str~pping as~embly 136, the inner core pi~ e 122, th~ knockout pin 130, and the f irst and second e j~tor a3~e~blie~ 1 5J~ and 164 . As the cavity plate 60 of the femal~ m~er 52 i3 moved upwardly, the plate 140 beco~es free to mcv~ upwardly, and the plat~ 1~0 i~ moved upwardly by the ~pring~ 150~
Al~arna~i~rely, w~th the arran~men~ de~icted in ~ig. 11, pl~te 140 may be moved upwa~d}y by mean~ of oyllnder~ 182 plate 19û, whi~h i~ rigidly ~ecurodl to th~ pl~t~ 140 of the mold~ S0 showll in Fig. i1. As th~ pl~t~ 1~0 i~ pushed upw~rdly~ ~h~t plate, first, pu~h~ the ring 138 upwardly;
and ~cond, pulls the bolt~ l52, th~ fir~t e~ector as~embly 1S4, ~d ~h~ inner cor~ me~ber 122 of th@ ~o~ as~e~ly 78 upwardly. Wi~h r~ference to F~g. 9, a~ the rin~ 13~ is push~d upwardly, thi~ ring, i~ turn, puJh~ ~h~ bo~tom of the cap upwardly, pu~hing the rib 8 a~d th~ thr~ad~ 4 ou~ of the rece se~ 1l4 and 116 of the outer cor~ pl~2 tl2.

. '" .~ ' ~ :, .. :: . , :
.:
'" ~

~7~ 9 - 1 9-E~ecause the rib 8 i~ puqhed - a oppo~ed to pulled ~- ou~ of the reces~ 1 t 4, the f Eang ible members 7 of the cap are not ~tretched~ but rather are compres~ed, ~9 the ~ib 8 is removed from the rece~s in which the ri.b 3 i~ ~or~ed. Thus, 5 the cap may be removed from the nnold S0 without exerting appreciable tensile force on the frangible members 7.
At the same time that the ring 138 i~ pu~hing ~he bottom of ~he cap upwardly, the inner core piece 122 and ~he knoc)sout pin 130 ar~ moved upwardly to pu~h the top of the 10 container cap away from the outer core piece 112. ~he inner core piece 122 iQ mov~d upwardly by mean~ o the fir~st ejector a~sembly 154 which, a~ dll4cus ed above, i~ pulled upwardly with the plate 7 40 by mean~ of the bolt~ t 52 . The knocXou~ pin ~ 30 i~ pushed upwardly by the ~econd eieceor 15 as embly 164, which itself i~ laoved upw~rdly by th0 knockout bars 174. The Icnockout barY 174 are pu~hed vi~ cyliQders 192 and plate 194 of molding apparatus 180 .
The stripper plate 140, the ring t38, the first e jector assembly 1 S4, arld the inner core pie~e 122 ~ontinue 20 to move upwardly untll th~ plate 156 o~ th~ fir~t ~jector assembly abut~ again~t the plate 98 ~ a~ shown iA l?~g 6, terminatiny the upwardly move~ent of the p~at~ 1~6, the first ejector a~@mbly, z~nd th~! inne~ core piece. At thlY time, the plate 156 of ~he e~e~tor a~ e~ably 154 al30 prevents 25 further upwardly move~ent of the bolt~ 152, prev~nt$ng further upw~rdly ~ov~ent of ehe plate t40. B~cau$2 th~
pl~ 140 ca~l no long~r n~ove upwardly, that plate doQ~ not forc~ the ~ 7~ or th~ ring 38 further upwardly, and the ca~ ~n~ ~h~ ring î38 ~ome ~o a 3top. The positi4n o3~ ~he 30 pl2lg~ 140, th~ ring 13~, th~ ~nn~r cor~ piec~ 122, and the kno~kout p~n t30 wh~n u~w~rdly ~o~eD~nt o~ th~ plat~ 140~ ~che ring 138; and the inn~r co~e piee~ er~in~tedl ~9 show~ in Fig. 8. I~e should b~ noted thz~ th~ ring 138 i$ e~oployed to pu~h the r ib 8 o~ the cap p~ the re~e~ 11 6 i~ ~hich the 35 thread~ 8 of th~ contain~r ~ap a~e ~or~ed. Tn th~ way, the , '~, ;
., :

~L~'7~335~3 -2 O-f ra~ible member5 7 of the cap are not stretched in ~ase the rib 8 rub~ ag~inst upper surface~ of the rece ~ 116 as that rib ~lide~ upwardly therepast.
The knockout pin 130 i~ f ree to cont$nu~ to move 5 upwardly from the po~ition ~hown in ~ig~ 10, howeverl and the knockout pin i5 ~10 moved by further upwardly movement of th~
second ej~ctor as~embly 1640 The knoc~out pln 130 directly contact~ the ~entral portion of the top of the cap, and a3 - the knockout pin is pu~h~d upwardly~ th~ knoc}sout pin forces 1~ the ~ap completely off and away from the outes and the inner core pieces 112 and 122~ from the po~ition shown in Fig, tO
to the po ition shown in broken line~ in Fig. 6. From thi~
positioll, the cap may be lifted off the krlockout piR 130, and completely remov~d f rorn the mold 50 by hand.
Once th~ cap i~ re~oved, the knos:ko~t bars 174 are pulled downwardly to the position in Fig 5, pulling the second ejector asc~embly 164 and the knockou~ pln 130 downwardly into their po~ition shown in Fig9 S. As th~ top plate 1 6a of ~h~ secolsd e jec~o~ a ~mbly 164 move~
20 downwardly, th~lt pl2~te engage~ the headl of th~ bolt 178 and pull~ that bolt downw~rdly. This pull~ t he plate 1 5a of the f ir.st e jeGtor a~3embly 154 dow~rdly, and this pu113 the plate 1 S6 of that ~eGtor as~embly ~own~ardly via the boltc 160. ~ gh~ pl~e 15C i~ pulled do~nw~rd, th~ plate for~es th~ inner core piece 1 02 downs~rdl via ~h~ re~ainer ring 1 62 and9 at the ~am~ e, or~e~ th~ bolt~ 15~ downw~rd, wh~ch in tu~n pull~ th~ plate~ 140 downw2~rd. Th~ rlng 138 and the cam~s ~4 ar~ pull~d dow~ward with ~h~ plat~ 1 4û 1 With the knodgoul: pi~ 130, the inner core piece lt2, the cam3 74, the 3~ ~trlpp~}~g a~e~bly 136, an~ the e~ctor a3~em~11e~ 15~ and 16~ all moved downwardly, th~ upper a3~en~ 1y of th~ emale member 52 i~ ~hen ~oved downwardly ~nto it~ c:lo~ed po~ition.
This force~ the cam~ 74 ~adially inw~rdly, is~to ~h~r closed position, rendering the mold 50 aga~n re~dy for ', ; -

Claims (7)

The embodiments or the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A mold for forming a plastic cap having a side wall and a ring spaced from the side wall by means of circumferentially spaced annular recesses and connected to the side wall by frangible members, the mold comprising:
a) a female member forming a socket and an orifice for conducting plastic material into the socket;
b) a male member having at least two portions including a core assembly axially extending into the socket to form a mold cavity with the female member (i) an inner portion of said male member adapted to be independently axially movable from its position forming a part of said mold cavity, and (ii) an outer portion of said male member being fixed in its position forming a part of said mold cavity, and c) the female member including (i) an upper assembly forming an upper portion of the socket, and (ii) a lower assembly having a plurality of radially movable cam members forming a lower portion of the socket, the cam members having radial protrusions engaging circumferentially spaced sections of the core assembly of the male member to form the circumferentially spaced recesses in the cap.

2. A mold according to claim 1 wherein:
a) the cam member rest on and are supported by the male member for sliding movement between i) a closed position wherein the radial protrusions of the cam members engage the core assembly of the male member, and ii) an open position wherein the cam members are spaced from the core assembly of the male member to facilitate removing the cap from the mold cavity; and b) the lower assembly further includes:
i) spring means engaging the cam members and urging the cam members to their open position, ii) stop means to limit movement of the cam members at their open position, and iii) means to guide movement of the cam members between their open and closed positions.

3. A mold according to claim 2 wherein:
a) the cams include upper surfaces sloping upwardly radially inwardly;

b) the upper assembly includes a lower surface directly above the upper surfaces of the cams and sloping upwardly radially inwardly; and c) said lower surface of the upper assembly is above and engages said upper surfaces of the cams to hold the cams releasably in the closed position.

4. A mold according to claim 3 wherein:
a) said lower surface to the upper assembly engages said upper surfaces of the cam members as the upper assembly moves axially downwardly to move the cam members from their open position to their closed position.

5. A mold according to claim 1 wherein:
a) the core assembly of the male member includes:
i) an outer piece having an annular recess to form an annular rib of the cap, and ii) a knock out pin axially extending within the outer core piece and supported for axial movement relative thereto; and b) the male member further includes:
i) an axially movable stripper assembly for engaging and pushing a bottom edge of the rib of the cap axially out of the annular recess of the outer core piece, and ii) means connected to the knock out pin to move the knock out pin axially upwardly to push the cap off the outer core piece.

6. A mold according to claim 5 wherein:
a) the stripper assembly includes a stripper ring extending around the core assembly to engage the bottom edge of the cap and to push the rib of the cap out of the annular recess of the outer core piece.

7. A mold according to claim 1 wherein:
a) the core assembly of the male member includes:
i) an outer core piece having a first annular recess to form an annular rib of the cap, and a second annular recess to form a thread of the cap, and ii) a knock out pin axially extending within the outer core piece and supported for axial movement relative thereto; and b) the male member further includes:
i) an axially movable stripper assembly for engaging a bottom edge of the cap to push the rib of the cap axially out of the first annular recess and past the second annular recess of the outer core piece, and ii) means connected to the knock out pin to push the knockout pin axially upwardly to push the cap off the outer core piece.