AU525925B2 - Closure cap with sealing gasket - Google Patents

Description

bmsert full name(s) aud address (es) of aipplicant(s).

V'(IHQNV q~t I[O] vNfIVN NI

G ni il Insert name of country.

Insert date and number of each application on which priority Is based.

SigiA~ture(io) of applicant If a Company, forin to be executed in a nI~nner binding on the uompany according to Its Articles of Association cr tho laws oi the country. b) Seal of Comnpany (if

Initial all Alt(Irgions.

A/2 4377

M-B-81 534,1/. 2

c 0 mm

4 Yarflhi*~ COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-1962 (ite: This is a comjrehensi WbIigned by the apphicatt(s) its behalf and the Company NO/ CON VESI ITIOiN APPLICATION FOR A PATENT

(~thf15 3 4 /7 (This /or~n may be esigned by the applicant or by the Australian Patent Attorney.)

MThOCTONS hsert full name(s) We W.R. GRACE CO., a Corporation wAd address(es) of organized and existingtfmde.r the laws of the State of (a)Isert No. if ()available. In $up appicant(s). Connecticut, United States of America, of Grace Plaza, insert full namejo) of aplicant(s). made I 1114, Avenue of the Americas, '.new York, New York 10036, United States of America, 4a) Insert tte of for a~ Invention. GA hereby apply for the grant of a Patent for an invention entitled "SEALING GASKE-S 'OR CONTAINER CLOSURES" Insert full Dame(s) of delarant(s) wbo I, (d) must be PERSON ar PERSONS, NOT a corporate body. Ceehbed note). of (e) 4*11Insert address(as) $d..lanut(sS. -Amtl which is described in the accompanying complete specification. Tile application is a

Canveption application and is based on the application(s) for patent or similar protec- do Boll (f e Jite entirely If applicant Is tion made in Great Britai~n corporate body. Insert namne of country. 4s) Ioltaentlcelr If apr4leant Is 1.(g) patton or persons. on 28th May, 1974 under No. 23611/74 and 2. Thi on 2nd July, 1974 under No. 29297/74. (ollowi raMme3 Insert date and number *f each application on ft0 elete entirely If in (i. which priority ia baaed. ~A Convention Prfrloit NOT claimed. by (k~ Insixt countrI 'which first basic in (i APp1IClaionWAS filed. by (k U(j Isert date of first Our address for service is care of DAY. ES &zCOLLISON, -Patent Attorneys, "itsleapplication. In~srt full mem(s) of baic Lby k A WIS. Building, Hobart Place, Canberra, oramoitwealth (if Australia. Delete entl'rsly If uppllcrt(si NOT 3. (lx, SInventor(s). tun)Jg rt full nme(s) 3. (m of actual Inventor(s) If applicant(s) NOT laseatoc(m).

Dated th5 26th day of May, 1975. of actual of (n) Inventor(s) If tc~pl1ciwt(*) NOT Inv~ntor(s).

xkj/are Signiture(ii) of Rtecite Manner In ,4s ri applicant(m). whigh applicant(s) If a Company, form to he derItt(s) titio from actual inventor(s) If Deaeds oxecuted in a nrnper (A member of the firm of DAN7IES COLLISON) applicantt(s) Now binding on the Co.rmpany InVentor(s). according toIs Articles for and on behalf of W.R. GRACE t CO. of Association cor Ait laws ot the country. Del.i entirety It Convention 3prlorlty

T4 b) Seal of Comipatty V9T clalngd. (if ms.) Feite Mannar 1I% ,which appllcsint(s) Th( diarivo(s) tti.f basic applent(s ig rt the fir subjec- fnitial all Altorations. basiewvo t(a). (r ipiature(s) of Declaz:4 (r dCItAnt(s). THE~ COMMISSM)NER OF PATENTS salor mitamnp ln~ression to beaapplied).

A/24~377

cortaincl

(profile

COMMON, E A L T 110 V U S I

PYATENTS ACT 1.952-19~69 primarl'i

A,/437: 2~2/ (Cmb)AUSTRALIA PATENT DECLARATION FORM

(C)NVENTION OR NON-CON VENTON) )to; This is a comprehensive form, and parta inappropriate to a particular case moust be deleted. This declaration must 9sgned by the applicant(s), if indiiduals. If applicant is a Company, this declaration must be signed by a person or Its behalf and the Company seal, or stamp, should not be applied.)

Forms 7and 8 EL 0N8 COMMONWEALTH OF AUJSTRALIA AJUL 1975 8,1 5 34/75 Patents Act 1952-1962 DECLARIATION IN SUPPORT OF A CONVENTION OR N 7 MNSTXUCTIONS APPLICATION FOR A. PATENT OR PATENT OF ADDffION Insert No. if In support of the application No.(a Inert full nameis) made by (b eR#GA of applicant(s).

for r, patenth xx& *A~i for an invention entitled __SA G 4a) Insert title of Invention. GASET FOR CONTAINER CLOSURES"_____

Jd) Insert full name(s) -OTfaioFavorito Assistant Secr,. ary of declarant(s) whio must be PERSON or. PERSONS, NOT a corporate body. ame bead note). of() 4 ve"' Insert adsu- Americs~N N ffWS± ,qf dwla'anta

do soleminly and sincerely declare as followvs:- 4f, &Ial. entirely If aplicant In eurporate body. 4s) ,P*leta entirely If apjplicant is peaton or persons.

S2. 1. I am authorized by the *bovemeittioned applicant for the x;jdii"4 make this declaration on its benalf. The basic application(s) as defined by SectioD 141 of the Act 3fW/were made in the followbag country or countries on the following date(s) by the following applicant(s) namely,:- a'reloteentirely If in (3)_Greci 'Britain o~(iV 'Stli May., 19 74 ConvRntion prfotdty NOT claimed. by (00 Inavrt country In~h which first basic in M(...Gre-at.frt..n. on ap lct~on was by WkW..*tPAC 9. l CO. Ix'sert date of first b..Ale application. in I of"b fulc name(s) by .uslcanl.(s). DeletA entirely If &aPPlIeant(alo NOT 0Inventor(s). tin) IXL~rt full 128=4(s) of actual Inventor(*) If appllcant(s) NOT' Inventot(A). (a netaddrees(se) of actual Inventor(s) If "PpllcAnt(s) NOT In.ntor(s).

is,1XD two actual inventorpa) of the invention and the facts upon which the applicant(s) Kkp/are entitled to make the application are as followis:- Ce) "ectemanner in a regards entitlement under Section 34 of the Act:- .PY42.t GOf whioh applicant(s) dertee*(s) title from eedsmf Asjqmet date 9th Mav, 1974 anti 1s~ Tuly~a actial inventor(s) if aLplwuatt(s) NOT Inventor(s).

Delesa entirely Ift r--as regards entitlement under Part XVI of the Act' Convention p~riority NOT clalmirA.

whichpifte na 4.Tebxi application(s) referred to in paragraph 2 of this Declaration xvai/were beeITO tppite the first application(s) made in a Convention country in respect of the invention the bu*r pive subject of the application.

Declared ait (Wmrl~g~ ao. this I 9th day of May £igntur(e) of 19 (MB No seat or vitamo InorcAslnn r4/

U~2) AUSTRALIAN PAIFENT ABRIDGMENT AUl AIJ-B-81 534175

(54) CLOSURE CAP WITH SEALING GASKET W.R. GRAGE AND CO. (21) 81 534/75 525 925 (22) 26.5.75 9 .5 .7, 24)N ?8 (31) 7423611 (32) 28.5.74 GB 7429297 2 .7 ./4 GB (43) 212. 76 (44) 9.12.82 51)2 ,61"D 53/02 B65D 41/04 B65D 41/12 (72 JAMiES JOHN ALEXANDER DAVIDSON (74) DC 39 978/172 a16Q 164 57.5, 57.2 508/68 57.5 27 901/67 43,6 194 (51) Claim 1. A method of closing a contai ner havitig a neck whi ch iz thrteaded and has a fi at-topped rim, which comprises p1 aciiig a qasketteid metal cap blank over the threaded neck cr the conta iner, pre.,si ng the cap blank down agai nst the neck of the container, and whilst holding it so prossed, reducing the diamete~r of "-ho ski rt of the cap blank, so as to compress the gasket hetijeen the top of the skirt of the cap blan!k and tohe side of the Pck of' the container, and aeforming trie ski rt of the cap blank so a't to Vcrm 'h-,eads therein which mate with threads or the neck of the contai- in which method the ga;sket in the ca, ,,lan1,, in i t: covifiquit--; before application tq the cootainor neck, comprises naf Iat it ra~ anelt occu pyi nq f rom 50 to 94 %of th e i nte rnalI radi us of thi cop blank an~d an adjoi nii 1rienpherai porti on occpying, Zthe r'!mini n~ 6 -to 50% of the radi us, the confi gurati on of the pci-ipheral porti 'la before ;ai d application being as

P 46*

If 44-11 C" ~Danc Dr, both -Ylcpc )wrds3 so that i- igirpo~sible to discern a Ix~jnt D, I~ a~c 1oigjiA 1f DF may be asuxnd to be the ooe&n of the

A/24377

(11) AU-B-1 534Y17 2 COMM0 1

follows, namely: considering the cap blank in an up-turned position relative to that which the cap occupies on the container and considering the peripheral portion in a radially outward direction, It comprises consecutively: a first part (AB) of relatively steep gradient upwards from the edge of the central panel which makes an angle with the plane of the central panel of from 25 to 900 and which has a radial length of from 5 to 30% of the radial length Application NI

(AW) of the whole peripheral portion (AE); (ii) an adjoining relatively flat step part of Complete Spec: constant gradient which makes an angle vith the plane of the central panel of from 0 to 250 and which has a radial length of from 10 to 70% of the radial length (AW) of the whole peripheral Priority-, portion (Ai); (iii) an adjoining corner part sloping upwardly, the Related Art: height (DX) of which above the plane of the step part is from to 65 of the height (DY) of the top of the corner part above the Name of Applio plane of the central panel, and (iv) an adjoining final marginal part IDE which extends Address of ApI to the skirt either as flat step or upwardly and wh1 .h has a ,,adial length of from 2 to 15% of the radial length (AW) of the whole peripheral portion (AE); and the cluoing of the cap blaoik onto the neck of the container is Actual InvEnti effected so that at least part of the flat area of thc rim of the neck ecomes pressed against at least part of the flat step part Addreas for S, W)

Complete Spec

"SO

Tha following invention, in, kcnown to uss- *1161/64/2

'I in pri,

enployed in Figuxoc 2 Figurp. 3 T is a nixtur cinchoiits (mm.) inches (nm.) optionally I

I -xtE,-naY di,:nterr--oyf o 1*102 1.102 (28.000) {28a00 1 *102n(Oe (28.000) 1.102 5 Polyothlcn

THE COMMISS50NER OF PATENTS

A/243 77 52'Cw!5 COMMAONWEALTH OF AUS

PATENTS ACT 1952-1969

COM~PLETE 5 PECIFICATION

(original) FOROFIC UE:815 34/n5 Class Int. Class /c~ Application Number: F< /-111", ~4\ L.odged:

Complete specification Lodged:' vi J )I

Aceepted.*c~ C)3 Published; C. A'

Priority, iL~

1-7'~ XCV I Related Art:,

Name of Applicant; W.R, GRACE CO,

Address of Applicant: Grace Plaza, 114, Avenue of the kxnericas, New York, New York 10036, Un.Lted States of America

Actual Inventor(s) JAME$ JOHN~ ALEXCANDER DAVIDSON

Advdrems for' Service:. Davion Collison, Patent Attor~neys, A.KP Building, Hobart Place, Canberra, A.C.T. 2601.

Complete specificktion for the inven-tion entitleds "SP_,ALXNG GASS )OR CONTAINER ClOSURBC-"

Tha following statemuent is a full description of this invention, including tb~e best mvthod of performing it kniown to us i~

Thit, invention relates to sealing ga~okets for

cortainer closures, in particular to the coifiguration (profile) of gaskets for threaded closures. Container closures are provided with gaske-:ts primardily in order to prevent air from entering the

cdntaincr and/or loiss of contents of the container to the outside. They are especially important in

closures for containars which hold food or drink since contam~ination of the food or drink within a container by the entry of air before consumption can be a serious

health hazard. A major area of use of gasketted closures is for the closing of bottles. In order to enable a customer to re-close the container af ter it has been opened it is desirable to

provide a threaded closure which oan be removed by unscrewing. One general type of threaded closure which has found widesprcad coxnorcia. acc,:.ptance is

the in situ-threadeG. type: threads are formed during or after the operation of closing the closure onto the conta.0n~r. Generally, a closure which is initially untbr,.aded is closed by pressure onto the neck of a

throJade-1 container, Further, lateral, pressure is then qpplied to ipart threads to the closure while it irs on the container, the threads formed in the closure corre spendixng to those on the nook of the container.

For cxample the threads may be formed with the aid of a roller. Closure caps having threads formed in this way are termed "roll-on" caps and, are usually used on bottles. Gaskots for closures of the above type have hitherto been prod uced by the so-called spin-line process., In the spin-line process a pre-detcr-minnC quantity of.a plastisol of polyvinyl chloride is metered into a closure, the closure is zpun rapidly about an axis through the centre of'the flat top of the closure so as to distribute the plastisol by the action of centrifugal force, and the plastisol in the closure is then fluxed. The plastisol is a viscous dispersion of polyvinyl chloride in a plasticiser. It is fluxed by heating it to a temperature at which the plasticiser is absorbed by the polyvinyl chloride to form a homogeneous mass, which upon cooling gives a rubbery solid.

The spin-line process, although commercially successful, has limitations. One limitation is that the profile of gasket cannot be satisfactorily varied. It is desirable to be able to vary the profile of a gasket according to the particular size of cap and dimensions of bottle employed. Because in the spin- line process the shaping is effected by centrifugal force the gaskets produced will inevitably gradually increase in thickness from the centre of the closure

to its periphery. Thus, if for a particular closure one wants to increase the thickness of the gasket near the periphery, it is necessary to increase the total charge of plastisol metered into the closure or to increase the centrifugal force applied. The former is disadvantageous because it results in a gasket which is also thicker near the centre of the closure;

this extra thickne:us at the centre is not required and thus there is a waste of the valuable plastisol. The latter is disadvantageous because the whole profile of the gasket is changed and plastisol may be thrown a considerable distance away from the top of the closure along the skirt, a position where it is not required.

Thus the relatively "fixed" profile of the gaskets

produced by the spin-line process is disadvantageous because of the difficulty or la-ck of economy in making minor variations to the profile. A second problem of the spun-line gaskets is

that for at least certain closures of the above- described type a relatively large amount of gasket is required to give an effective sealing performance. Another problem of the spin-line process is that

in large production runs it is difficult to introduce -th. e gasket-forming plastisol symmetrically into the

region of the centre of the closure, with the result that wen the closure is spun the sealing portion is

<13 5 not formed consistently in the shape desired. Yet another problem is that the choice of materials used for the gasket is limited to those which can be formulated as a viscous liquid for 3pinning, such as a polyvinyl chloride plastisol. In ourh Patent

we have proposed certain gaskets of diffeient profile from those produced

_-by the spin-line process. These gaskets are 11seful in the in situ threaded container closures in general,

and may be made by moulding. Considered in their o 0 undeformed configuration, i.e. before the closure is

closed onto the container, these gaskets comprise a substantially flat central panel and an adjoining

peripheral portion, the thickness of which is at all poihts greater than the thickness of the central panel and increases continuously and/or stepwise radially outwards to the skirt of the closure. To express this profile in another way, consider the closure in its inverted or up-turned position, meaning the opposite way up to which it is seen when closed onto a bottle. The peripheral portion of the Airrjitao.. PQa-t d se-c:h'o No 4-S'?30O gaskets of/British Patnt-Ap~ition-6467-3-extends to a point on the skirt of the closure which is overall upwards from the central panel of the gasket. Considered in the direction of increasing radius from the centre of :the closure (the radially outward direction), the height of the peripheral portion above the central panel starts by increasing and thereafter either continues to increase or remains the same. *3 The gaskets of/sbch- _atent App Ne- "-aation

-35746/-3- having the above-defined profile enable the above-described problems to be overcome, at least to

a considerable exten'ct They do not require such large

amounts of gasket material. Since they are made by

moulding, their profile can be varied, it is easy to

introduce the gasket-forming material into and form it centrally in the closure and a wide variety of different materials may be employed.

The present invention is concerneC specifically

with gaskets for in situ threaded caps, especially roll-

on caps, which are to be closed onto the container by a A J9

0, "reform" operation. In this operation force is exerted

during the closing of the c not only downwardly but h

also laterally of the skirv )f the cap, so as to pinch the top of the sk.irt inwards. In other words, the diameter of the skirt of the cap is reduced so as to compress the gasket between the top of the skirt of the cap and the sid of the neck of the container. A

"reform" operation of this type is described in

British Patent Specification No. 975,739.

Among the general class of gasket profiles

described in .ustralian Patent Specification No. 487360, certain profiles are described as giving a good

sealing performance when the cap is subjected to a

reform operation. We have now found certain other

profiles within this general class which 5At only give

a good sealing performance in this operation, but

possess another advantage not enjoyed by the general.

class or by the profiles specifically disclosed for use

in the reform operation.

A first aspect of the present invention

provides a method of closing a container having a neck

which is threaded and has a flat-topped rim, which

comprises placing a gasketted metal cap blank :;ver the

threaded neck of the container, pressing the cmp blank

down against the neck of the container, and w:ilst

holding it so pressed, reducing the diameter cif the

skirt of the cap blank, so as to compress the gasket

between the top of the skirt of the cap blank and the

side of the neck of the container, and deforinig the

skirt of the cap blank so as to form threads therein

which mate with threads on the neck of the container,

in which method the gasket in the cap blank, in its

configuration before application to the containei neck.

comprises a flat central panel occupying from 50 to 94%

ib of the internal radius of the cap blank and an adjoining peripheral portion occupying the remaining

6 to 50% of the radius, the configuration of the

peripheral portion before said application being as

follows, namely:

considering the cap blank in an up-turned position

relative to that which the cap occupies on the

container and considering the periph-eral portion in a

radially outward direction, it comprises consecutively:

a fixot part (AB) of relatively steep

gradient upwards from the edgt of the central panel which

makes an angle with the plane of the central panel

of from 25 to 90° and which has a radial length of from

to 30% of the radial length (AW) of the whole

peripheral portion (AE);

(ii) an adjoining relatively flat step part (BC)

of constant gradient which makes an angle with the

plane of the central panel of from 0 to 250 and which

has a radial lgth of from 10 to 70% of the radial

length (AW) of the whole peripheral portion (AE):

(iii) an adjoining corner part (CD) sloping

upwardly, the height (DX) of which above the plane of

the step part is from 20 to 65%0 of the height 'DY) of

the top of the corner part above plane of the central

panel, and

(iv) an adjoining final marginal part (DE) which

extends to the skirt either as flat step or upwardly and

which has a radial length of from 2 to 15% of the radial

length (AW) of the whole peripheral portion (AE):

and the closing of the cap blank onto the neck of the container is effected so that at least part of the flat area of the rim of the neck becomes pressed against at least part of the flat step part (BC).

A second aspect of the invention also

provides a container closed by the method of the

first aspect.

Generally the peripheral portion of the

gasket will occupy only a small area of the total

surface of the flat top of the cap. The area occupied o 10 is conveniently defined in terms of the maximum internal

diameter d of the cap and the radial length x of the

flat central panel (measured from the centre of the

cap to its edge where it adjoins the peripheral portion).

The distance x may be from 25 to 47% of d, but will not

usually exceed 45% or be less than

We have found that the method of the invention

is much easier to perform than is the case with many

of the gasketted cap blanks described in Australian Patent Specification No. 487360. The latter caps

U' often become cock,-ed -at of their correct alignment when' the closing head is brought to bear on them, with the result that the cap is not closed at all or is closed in an off-centre manner. An off-cenhre cap will often fail to give a good enough seal.* In the gaskets of the invention this disadvantage can be at least mitigated. We believe that the main feature of the gaskets U-soA k- the invention responsible for the improved perioxmance in the closing operation~ is the provision and location of the step portion It appears that step portion (ii) bears against the rim of the neck of the bottle in such a way as to reduce the chance of cocking during the closing operation. Thus the stop portion (ii) should be so located that at least a part of it, and preferably at least half thereof measured along the radius bears against at least part of the flat area of the rim of the neck of the bottle. In general its radial length will be from about 1.0 to 70%, the optimum radial length &eiiding inter alia upon the configuration of other parts of the peripheral portion, as described hereinafter.

Since the gaskets are ordinarily made by moulding gasket material (within the cap blank), the problems associated with the spin-line pr:ocess are avoided. Preferred embodiments of the invention will now be

described in more detail, with areference to the accompanying drawings, in which-, Fig. 1 is sectional view of a gasketted cap blank of-~ Yf~i~ taken through a diameter, the cap being in an up--turned position relative to its position on a container; Figures 2, 3 and 4 are enlarged -views of part of gasketted cap blanks

4w~te- hwn the configuration of the peripheral portion of the gasket they are sectional views taken through part of a radius; and Figures 5 and 6 are side views of the top portions of bottle necksl-eznto ihgk~tdzpblar~1 of the invention. Referring to Figure 1, the cap blank I shown has not yet been Closed onto a container. It is made of thin aluminium, typicail1y 0.006 to 0.012 in~ch (200 to 300 maicrons) thick, and will normally be lacquered on the inside and outside. (However, the presence of a lacquer or its nature is not criticai. to the present invention). It has a flat top 3 fromd which depends a skirt 5 bent over at its other end into a bead 6 defi'liing a mouth 7. The gasket, having a configuration in accordance with the present invention, consists of a peripheral portion 2 beginning at a radial distance xc from thte centre of the flat top 3 of the cap blank and adjoir~ing a central pan~el 4. Tbe distance d nk~rkcad is the maximum internal diameter of thn cap blank. For a cap blank having an external diameter of 28 mm.,

'd i~s 1.092 inch (27.7 nun., The diameter of the cap .Aank.is not oritical and the/invent~or. is applicable to cap blan"Ks having a variety of different diameters, incl.uding the cortmonly employed bottle cap blanks of external diameters 26, 28 an~d 31.5 nun. Some~ cap blaniks have a knurled band stamped therein

j1ust above the level of Lhe gaeket. A main purposen of

~r~i#llra8sr~

this band is to stop the gasketting material from being flung too far along the skirt in'the spin-line

process. Thia band i not needed in the present invention and so is not sl.own in Figure 1, but it -oull of course be provided if desired. Figures 2 and 3 show the peripheral portions 2 of two gaskets in accordance with a 'first embodiment of the invention. These Figures have been labelled geometrically to show distances and angles. We refer first to the geometric labelling of Figures 2 and 3 to explain the invention generally. The peripheral portion 2 of the gasket has an upper surface defined by the line ABCDE. The first part AB has a relatively steep gradient upwards from the edge A where the peripheral portion 2 joins the central panel 4. It may have a planar or convex slope, preferably convex for

ease of mouliing The angle P is between 25 and The radial lengtn of the portion AB is from 5 to more usually 5 to 20%, of the radial length AW of the whole peripheral portion AE. In principle the radial distance AB could be greater, thereby producing a less sbeep gradient f r any given height of B above the central panel, but since part of the aim of the invention

c,o is to take advantage of every reasonable economy which a o 2C can be made in gasket material vithout adversely affecting the quality of the seal, a length of more than 30% on o

the above basis is of little practical interest. Because the gasket can be moulded it is possible to make the gradient AB fairly steep and thereby economiise uon gasket material.

The second step portion BC may be flat or have a

slight ipward slope so that the angle a~ may be from 0 to 250 usually 0 to 150 and preferably 5-10d. The

radial length of the step portion BC will generally, be from 30 to 70, preferably 40 to 60 porcent of AW. The optiTum height XY of the step portion above the

level of the central panel 4.will, depend on the resilience and 1t-oughness of the gasket material em~ployed d may

also diepend on the nature of the neck of the bottle.

This will be discussed farther with reference Figures 5 and 6. The "corner part" CD will normally have a 170ncave

slope when viewed as j, Figures 2 and. 3, but a planar or slightly convex slope might be appropriate for some purposes. The Iheight of CD will vary according to

preciselyr how xiuch gasket m-aterl.aJ it is desirable to

have pressed into the corner, of thF;. cap when the cap blank is closed onto the bottle. in otene:al the alistance

DX will be from 20 to 65%11 of the total height DY of point D abova the central pcunl. The distance of point D radially "'iom the centre

o~f the cap co:'-responds to the radius of tLhe moulding member employed to mould the gaskets. Thus the remainder of the peripheral portion, represenf-nd by DE: is the radial tolex.ance of thc moualding opearation,. The

dimension!, of the portion DE therefore have no great significance in theivzlves but DF4 will generally slo_,)e upwards eg as Ii Ficure 2 or be flat as in FigUrL .3. The radial lengqOh DE may constitute between 2 and

15% of the radial longth AW of the whole peripheral po-,rtion.

If thbe portons %CDand Dr, bath slo-Pe upwards so that i- is impossible to discern a point D, the radial length DE may be assumed to be the toLerance of the

mouL. q; member within Lap- cap.

All the corners at points A, B and C are preferably roundee:L sligh(tly, for ease of moulding, but in prin~ciple ~~could be sharply defined. tJ Table 1 grives the dir'aen ;ions applicable to somne

particuLar gasketlted cap blank-, in accordance with

Figures 2 ax~d 3,,t

00

0

o 0

12

had boon U:30(1 fox the gJvjl:et, A slij) a&aditivii would theia be vu-Cful to ecr:L-' the rolloval torquo. lesult.- aro dI-own in 11X,0ie 4 bolow. 1the rk-moval to .qucJ

N,03(c Obt~a.lect '10fa Z aV(oraJOC. 10 iLa~vpl t o.pt i~n tho

Ak=_.LW_.,A

'IAY3L~ *I~

Figure 2 Figure 3

inches (mm.) inches (nun.)

External diameter of 1.102 (28.000) 1.102 (28.000) c3i,o sure

L Internal diameter of losu)'e d 1.092 (27.737) 1.092 (27.737)

Jistance x 0.425 (10.795) 0.400 (10.160) Ratio x/d 0.39 0.37 Radial lenqths of AB 0.0223 (0.566) 0.0203 (0.516) of LC 0.0521 (1.323) 0.0791 (2.009) of CD 0.0331 (0.841) 0.0331 (0.841) of DE 0.0135 (0-343) 0.0135 (0.343) of AE 0.121 (3.073) 0.1460 (3.708) Heights YZ (central panel) 0.006 (0.152) 0.006 (0.152)

XY 0.0416 (1.057) 0,0341 (0.866) DX 0.0336 (0.853) 0,0336 (0.853) Radii of curvature At A (concave) None 0.10 (2.54) At B (convex) 0.27* (6.86) 0.015* (0.38) Of CD (concave) 0.040 (1.016) 0.040 (1.076) Angles _dgrees) 4 S10 4. S

u P 50 36 ot0 Gasket material: Mixture of equal parts by weight of

polyethylene and butyl rubber

The whole portion AB (except' for The concave radius at A in Fig. 3) has a convex slope of this radius of curvbture.

In principle, any gasketting material may be

employed in the present invention, A preferred material

is a mixture comprising polyethylene, butyl rubber, and

optionally an ethyl(ene/vinyl acetate copolymer. Polyethylene/butyl rubber mixtures containing e.g. 40-70%

by weight of polyelthylene and 60-30% by weight of butyl rubber are generally suitable. Gaskets are preferably

formed from these mixtures by cold-moulding as described

e.g. in our British Patent Specification No. 1,112,023, Australian Patent Specification No, 420,653 and German

Auslegeschrift 1,544,989. Other usable gasketting

materials include plasticised polyvinyl chloride and other vinyl chloride polymers known in the gasket- making art, other materials described in our British P'atent Specifications Nos. 1,112,024 and 1,112,025

-and thermoplastic copolymers of butadiene with styrene, optionally in admixture with other materials such as polyethylerie. S This class of materials is described in

our British Patent Specifications Nos. 1,196,125 and

1,196,127, The gasketting material is conveniently, but need not be, introduced into the cap in the form of a solid. It nay be a plastisol of a vinyl chloride

polymer, Such-a plastisol can be moulded by the process described in our British Patent Specification No. 1,239,927. The gasketting materials may of course contain any

of the usual additives such as a stabiliser, plasticiser, pigment, dye, filler, slip agent or lubricant. Although, as explained above, a wide choice of gaskettirg materials is available, certain practical

14

I.: considerations influence the choice of materials. problems To provide a good gasket for an in situ threaded The closure regard must be paid both to sealing performance by refere and to the need to be able to unscrew the closure easily .which sho from the container. In general terms a gasket made of the perip a soft, relatively resilient, material will give an within a excellent seal but will cause the closure to be Figu difficult to unscrew. Conversely, a gasket made of same refe a hard, relatively unresilient material will not give and 3. a very good seal, but will allow the closure to be 10 gaske t t unscrewed easily. It is necessary to strike a to Figure balance between the two requirements. length is We have now found that this balance can more easily of the wh be struck if the dimensions of the peripheral portion The of the gasket, in particular of the flat part (ii) slight up and the corner part (iii), are modified from those to 250 us recommended in the above-described first embodiment of radial le n the invention. In general terms, the nature of the a;t least modification is to enlarge the corner part (iii) both length AW in the radial direction and in the direction parallel 20 15-25%.

*0 to the skirt of the cap. To do this it is necessary 30-70% re to reduce the radial length of the step part (ii) optimum h 0 0

someqwhat. Too severe a reduction of the step part of the ce would reduce the resistance of the cap to cocking during and tough the closing operation. The second iRbdment of the 'i5 also depe c,,

invention is therefore concerned with a delicate selection 0) discussed of dimensions which alters the balance between sealing 00 The performance of the gasket and unscrewability of the cap slope whe so as to permit relatively hard gasket materials to be slightly used with better results, yet still mitigates or overcomes 30 purposes,

I cc

plane of the central i-nel of from 0 to 250 and which 6,

has a radial lenth of from 10 to 70% of the radial wherein th

length (AW) of the whole peripheral portion (AE); located im larger dia

(iii) an adjoining corner part (CD) sloping upwardly, of the cap

the heiaht (DX) of which above the plane of the step proniems or cocKing curing tne c.os.ing operaion. The second embodiment will be better understood by reference to Figure 4 of the accompanying drawings which shows in section, taken through part of the radius, -the peripheral portion of a gasket of the invention within a cap blank. Figure 4 has been labelled geometrically with the same reference letters and n'umerals as for Figures 2 and 3. Referring to the peripheral portion 2 of the gasket, the first part AB is as described with reference to Figures 2 and 3, except that its preferred radial length is 15 to 30 percent of the radial length AW of the whole peripher'al pofrtion AE.. The second step portion BC may be flat or have a slight upward slope so that the angle a may be from 0 to 250 usually 0 to 150 and preferably 5 to 100. The radial length of the step portion BC will generally be ;ti least 10 but less than 30 percent of the radial S length AW of the whole peripheral portion AE, preferably 15-25%. This is distinguished from the range of

30-70% recommended for the first embodiment. The °o optimum height XY of the step portion above the level

of'the central panel 4 will depend on the resilience

o, and toughness of the gasket material employed and may also depend on the nature of the neck of the bottle, as

o discussed further with reference to Figures 5 and 6. "o The "corner part" CD will normally have a concave

slope when viewed as in the drawing, but a planar or slightly convex slope might be appropriate for some purposes,, The radial length of CD should be from 25 to

V A

6, A method according to any preceding claim wherein the neck of the container has a ring thereon located immediately below the threads and having a larger diameter than the internal diameter of the mouth of the cap blank.

48% of AW. In a closure of internal diameter about 1

inch (25-30 mnm), CD is preferably concave with a

radius of about 0.045 to 0.06 inch (1,1 to 1.5 nun.). The height of CD will vary according to precisely how much gasket material it is desirable to have pressed

into the corner of the cap when the cap is closed onto

the bottle. In general the distance DX will be from

to 65% of the total height DY of point D above the central panel (compared with 20 to 60% in the first embodiment). The ratio of the radial length of corner portion CD

to the step portion BC should be at least about 0.8:1. It could be made as high as, say, 4.7:1 depending on the

precise combination of sealing, unscrewability and anti- cocking properties required. Towards the higher end

S* of this range cocking problems may begin to re-appear, .and the preferred range is about 0.8:1 to 1.7:1.

o Of course, if a softer gasket material were used the ratio could be as low as 0.6:1, e.g. in a cap of internal diameter about one inch (25-30 mm.) in which CD is

concave with a radius of about 0.04 inch (1.02 mm.). However, the removal torque may then become rather high. o The portion DE is as described with reference to

Figures 2 and 3. All the corners at points A, B and C are preferably

rounded slightly, for ease of moulding, but in principle they could be sharply defined. The above-given dimensions have been found particularly

suitable for gaskets made of mixtures of polyethylene and butyl rubber containing more than 50% and up to

17

the plane of the central panel,

13. A method according to claim 12 wherein the radial length of BC is 40 to 60% of AW.

I A. a ii-m' rrrili nr -Fn r+ aim 1 c-ib.qi--,qrtiti11v polyethylene, by weight; such gaskets are defined in our British Patent,No. 1,112,025. They are also suitable for gaskets made of mixtures of polyethylene with a thermoplastic copolymer of styrene and butadiene as defined in our British Patent No. 1,196,125.

These mixtures are harder than 50% butyl rubber compositions and impart a lower removal torque to the cap. For example gasket No, 1 of the

Table below has a removal torque, measured after 3 days, of about 20 inch-lb. (23.0 kg. cm.) when the

gasketting material is 50% polyethylene/50% butyl

rubber and about 12 inch-lb. (13.8 kg. cm.) when the

gasketting material is 70% polyethylene/30% butyl rubber.

'It is possible to reduce removal torque by including a slip additive in the gasket composition typically

in a proportion of up to 1.5 weight percent based on the weight of the gasketting polymer. However such an

additive is often difficult to mix with the gasketting polymer, especially if more than about I weight percent has to be added. An advantage of the second embodiment

of the present invention is that satisfactory renoval

torques can be obtained without recourse to adding large amounts of slip 'additive. Table 2 gives the dimensions of one particular gasketted cap blank in, accordance with Figure 4 and, repeats for comparison, the dimensions set out in Table 1 fo:r a gasketted cap blank inaccordance with Figure 2.

[6)

Izi

TA Ur, 2

Fiqurc- 4 inches (rim-) inches (mm. Y

External diameter of 1.102 (28.000) 1.102 (28.000) closureII Internal diameter of 1.092 (27,737) 11.092 (27.737) closure dI Distance x 0.425 (10.795) 0.41$ (3,0.541)

Ratio x/d 0.39 j 0.38

of AB 0.0223_(0.566)JLO110323_(0-820)

of BC 0.0521 (1.323) 0-0315 (0.800)

of CD 0.0331 (0.841) e0537 (1.36-1)

of DE. .0135 (0,343) 0.135(0.343)

of AE (A)04141 (3.073) 0.131 (3.327)

Ratio of radial langths of CD/B3C 0.64 1.70

15 Heights YX (central. panel) 0).006 (0-1521) 0.006 (0.152)

Xy0.0416 (1.057) 0.0416 (1.057)

DX 0,0336 (0.853) 0.0545 (1.384)

Radii of curvature jAtA concaveo) 1orla 0.10 (2.54)

AtB (convex) 0.027* (G.86) 0.027* (6.86) p,.

o 0 of CD (concave) 0.040 (1.016) 0.065 (1.651) Q

p., Pngle0s (degrees)

36__ .0

S 0.J S

C

o 25 Th~Qe whole portion A\B (except for the concave radius 0

O 5 at A in ]ig. 4) has a convex slope of Lthis radius oQf 6urvat,e.

8 15 34175

1 L

Considerable variation is possible from the dimensions given in Tables I and 2 but in general the overall weight of gasket material ("film weight") will be less than the 450 mg. frequently needed for spun-lined gaskets in this type of cap. A film weight as low as about 250 mg. can be attained by the present invention. The method of closing the cap blank onto a container comprises placing the gasketted metal cap blank (which in of course made of thin metal, e.g. aluminium of thickness

0.008 to 0.012 inch [200-300 microns])over the threaded neck of the container, pressing the cap blank down against the neck of the container, and whilst holding it so pressed, reducing the diameter of the skirt of the cap blank at a position above the threads on the

neck of the container, so as to compress the gasket material between the top of the skirt of the cap blank

and the side of the neck of the container, and forming threads in the skirt of the closure by deforming it at a position and in a configuration corresponding to the

threads on the neck of the container. The reduction of diameter of the skirt may be effected by usa of a closure head oF suitable shape, as described in British Patent Specification No. 975,739. This operation will normally precede the operation of foxrmng

the threads. moA\,oA U.SCA I"l The-eojleoee of the invention may be/ e aod onto a variety of containers, but it is envisaged that the invention will be of use mainly for caps closable onto glags bottles. The glass bottles may have necks of various types. One type common in the U.K. is shown in Figure 5. The neck has a reinforcing ring 11 located below the threads 12. If the peripheral portion of the gasket is too thin the cap will be pressed too far onto the bottle, causing the head of the cap to hit the locking ring. This collision With the locking ring will damage the cap and the seal. If the cap is pressed onto the bottle slightly out of the correct vertical alignment, i.e. if there is cocking, the lower end of the cap may strike the reinforcing ring. The flat step part of the peripheral portion helps to prevent this from happening. The invention is therefore of particular use in rt lation to containers having on the neck a ring located immediately below the threads which is of larger diameter than the internal diameter of the mouth of the cap blank. Figure 6 shows a "pilferproof" neck, the so-called "'ICA finish", widely used in Germany, Belgium, Nether.lan-1s and Luxembourg. The reinforcing ring in Figure 6 takes the form of a locking band 11 located below threads

12 i5 thicker, but of small diameter than the ring 11in Figure 5. A cap with a long skirt is employed, so t, the skirt is closed over the locking band 1I and into the area 13 of narrower diameter below it. The cap is then pressed into the container neck in the area 13 A na.:row band which is easily fracturable is provided in the skirt of the cap in the region corresponding to the locking band 11. It is then impossible to unscrew the cap from the neck without causing fracture at the said narrow band,

The diameter t of the threads in Figure 5 is

typically 1.063 or 1.088 inches (26.00 or 26.65 the

diameter e of the rim correspondingly 1.000 or 0.975 inch (25.4 or 24.8 mm.) and the height h from the rim of the

neck to the top of the reinforcing ring about 0.58 inch (14.7 Typical dimensions for Figure 6 are: t 27.65 mm., e 24.92 mm. and h 9.65 mm.

The rim of the neck has a flat top 14 which at its circumference curves downwardly to meet side wall 15. The

radially outermost edge of the flat top (flat area) of the rim is marked by F. When the rim contacts the

gasket initially in the closing operation, places beyond F on the rim in the radially outward direction should not contact the gasket places radially inward of B

within the cap blank. The gaskets may be formed within the caps by

moulding them, using a punch. A quantity of gasketting

material is deposited within the up-turned cap which, when appropriate, may be pre-heated. It will normally be

necessary to heat the gasketting material to soften it.

It is then moulded with the punch, whici. may optionally itself be heated. The methods of moulding well knowni to thoso sk-illed in the art of sk~tting "crown"g bottlre; caps have general applicability. Although moulding is very advantageous, the invention lies primarily in the configuration of the gasket. Therefore any meLthod of producing this configuration is in Drinciple acceptable, and the invention is not to be con~itrued as limited by

the process of making the gaskets. 13 The invention includes containers, especially bottles filled with beverages for human, consumption, '4XQ, Y\Oktxd -"losed by/ -~6of the invcntion. in the following Examples tests are reported showing the excellent seals which can be obtained. Percontages are by weight.

EXMPLPE 1 A cap blank of Figure 2 containing a polyethylene/ butyl rubber gasket and having the cap bI ank amid gasket dimensi.ons given in Table I and a ga.-Act filM weight of 259 mg. was closed by a reform operation onto glass bottles having the standard "continuous thread" finish shown in Figure 4. The force of the -lIosing 12rad was 320 lb. (145 kg.) and the sier~.rforce on the skirt of the cap blank was 40 lb. (18.1 For comparison caps lined with 470 mg. of a spun-line polyvinyl

chlorida gasket were closed olito the same type of glass o bottles under the same cond~itions.

1Xo problems of '"cocking" occurrd,

Vonting prossoue tcestv showod that cap8 havinU both kinds of gasket had excel'.ont rosistilzee to the inteirnal pressure ofC gases, o.uch as are paresent in carbonated beverages, there being li tle difference between the two sets of results (gee Table Venting pressures were determined as follows The caps were closed onto glass bottles with a hole cut in the bottom. The necks of the bottles were immersed in a water bath so that the cap was under water. The bottles wore pressurised with compressed air introduced through the hole in the bottom at a rate of 10 p.s.i. (0.7 kg./sg. cm,).per 10 se conds, until bubbles appearea in the water ind.*cating Iailure ot the seal or the pressure reached

120 9.s.i. (8.4 kg./5q. Attainment of this pressure indicates a satisfactory seal, Table 3 venting pressures (sL-x Samples)_ .IIA ()XI~fk(AACG%£KIIVA r,1aAXX4 cap/of present invention-, >120, 110, >120t >120 >120Y >120 p.s.i. Cap) containing spun-line >120, )120, 115, 115, gaskct: >120$ >120 p.s.i. (110 p.s.i. 7.~7 kg./sq. cm; 115 p.s.i. 8.1 kg./sg. cm; '120 p.s.i. 8.4 kg./sgq. cm.). TsExample shows that a far lower film weight is possible in the present invenion than that used in a cap gasketted with a spun-line gasket. Part of the decrease in film voight is attzibutable to the use of a material which is less dense than polyvinyl chloride, the specific gravi Ly of the polyethylono/butyl rubber U 9gasket being 0.9 compared with 1 .2 for the polyvinyl

chloride one. However, poytyeebtlrubber mixture is not usable in, the spin-line process and it is a particul ar advantage of the invention that by providcing a buitablc Configuration for a gasket which can b, )ul(1c, it iS p)Osslblo to use polyotbylene/butyl rubber. Moreover, the docreasec in filmn weight jtvi,-jjutablo to dftecein density of the gaskot material., is only 25~ ot ofJ a total d,'c=ase ot

I I~

I EXAM4PLE 2

Pellets of gasketting material were moulded into gaskets in a 28 mm. .ll-on bottle cap blank of thin

alumfili-ula. Three different main types of gaskets

were molilded details3 as follows: Composition of g asketting Configurat; ion mater, al in ivniThht %ogasket 7030 polyethylene/0%L Figure. 2/T able butyl rubber 2 polyethylene/A"O' Figutre 4/IT abla butyl rubber 2 polyethylene/50'/O Vigure 4/T able thermoplastic styrene- 2 butadiune cor-olymer "Cariflex TR 11021" Polyvinyl chloride Spun-line plasti.sol acccerding to prior art: formed by spinning the closar about an axis through its centre)

Gaskets were moulded f-cr-a compositions A, B and C containing no slip additive and various pxoportions of an oleamide slip additive.

Removal torques were determined after allowing the gaskets to age for one day. Some samples wcre subjected to venting pressure tests to deteximine the strength of the seal. The results show that all the g~skets imparted atisfactoary removal torques, i~e. good unscrewability,

to the caps, but Uas~rts A according to Fioiu:e 2 did not give a satisfactor sea]. because of ;;he hardness of the

materiol chosen. On the other hand, oxcellent seal

and low removal torque were obtained from 1he gaskets B and C. (It will be understood thalt_ the Figure 2

gasket would have, given a good oeal if a soiter mater-ial

C, 4

had been used for the g,:,sket. A slip additive would then be useful to ecrea.e the removal torque.) Results are shown in Table 4 below. The removal torques were obtained as an average of 10 samples, except in the instances otherwise noted.

TABLE 4

Remnoval. torques after'l day in inch lb. (kg. cm.) slip additive A B C D 0 10.5 (12.1) 1-2.1 (13.9) 10,5 (12.1) 9.2" (10.6o) 0.1 7.9 8.4 7,,2 (8.3) 0.2 7.9 8.3 5.G (6.7) 0.4 6.8 7.4 6.0 (6.9) 0.7 5.4 7.3 4.9

7.6 8.7 (10.0) 5.1 154.4* 4,.1 (4.7)1' ~'average of 9 sa,,ples Saverage of 6 .roles

Venting pressures of 2 samples of A (containing 0.1 and 1.550 slip a',dIitivo) were only 25 and 35 (1 .75 and 2.45 g/jr#cx-.) respectivec Venting pressure- wore Srrinc,$ on 25 samples of B3 and C. Two samplos of B3 ancl 01n Of C contai ning no -,lip agent, wAithstood pressures of 1,10, 112, and 120 p.s.i. (7.71 7.8 and 8,4 kgb/cm. 2)

XOP'-activel.y and the other 22 withstood pros.ures of

Ovce. 120 p.s.i. (over 8.4 kg./crt,

In the foll~owing claimn letters have boon inserted in parcenthesim in order to tacilitateo reference bcetween claims and dencripLion and. betwecn one claim and another. They arc inot t1-o bo, understood as in any way liniiti n' the scope 02. the claims,.

I

Claims (1)

1. The claims defining the invention are as follows:

   1. A method of closing a container having a

   neck whih is threaded and has a flat-topped rim,

   which comprises placing a gasketted metal cap blank

   over the threaded neck of the container, pressing the

   cap blank down against the neck of the container, and

   whilst i.olding it so pressed, reducing the diameter of

   the skirt of the cap blank, so as to compress the gasket

   between the top of the skirt of the cap blank and the

   side of the neck of the container, and deforming the

   skirt of the cap blank so as to form threads therein

   which mate with threads on the neck of the container,

   in which nethod the gasket in the cap blank, in its

   configuration before application to the container neck,

   comprises a flat central panel occupying from 50 to 94%

   of the internal radius of the cap blank and an adjoining

   peripheral portion occupying the remaining 6 to 50% of

   the radius, the configuration of the peripheral portion

   before said application being as follows, namely:

   considering the cap blank in an up-turned position

   relative to that which the cap occupies on the container

   and considering the peripheral portion in a radially

   outward direction, it comprises consecutively:

   a first part (AB) of relatively steep

   gradient upwards from the edge of the central panel which

   makes an angle with the plane of the central panel of

   from 25 to 90" and which has a radial length of from 5 to

   of the radial length (AW) of the whole peripheral

   portion (AE);

   (ii) an adjoining relatively flat stop part (BC)

   of constant gradient which makes an angle with the plane of the central 4-nel of from 0 to 250 and which has a radial lencrth of from 10 to 70% of the radial length (AW) of the whole peripheral portion (AE);

   (iii) an adjoining corner part (CD) sloping upwardly,

   the height (DX) of which above the plane of the step

   part is from 20 to 65% of the height (DY) of the top

   of the corner part above the plane of the central panel,

   and

   (iv) an adjoining final marginal part (DE) which

   extends to the skirt either as flat step or upwardly

   and which has a radial length of from 2 to 15% of the

   radial length (AW) of the whole peripheral portion (AE);

   and the closing of the cap blank onto the neck of the

   container is effected so that at least part of the flat L),2 co"VV2-

   area of the rim of the neckie pressed against at least

   part of the flat step part (BC).

   2. A method according to claim 1 wherein the

   corner part (CD) has a concave upward slope.

   3. A method according to claim 1 or 2 wherein the

   angle a is from 5 to 100.

   4. A method accordiiig to claim 1, 2 or 3 wherein

   -the first part AB has a convex slope, the angle P being the angle which a planar slope from bottom to top (B)

   of the part AB w uJd make with the central panel.

   A method according to any preceding claim

   wherein the cad blank is a bottle cap blank having an

   internal diameter of from 25 to 32 rm.

   6. A method according to any preceding claim

   wherein the neck of the container has a ring thereon

   located immediately below the threads and having a

   larger diameter than the internal diameter of the mouth

   of the cap blank.

   7. A method according to any preceding claim,

   wherein the radial length of the step part (BC) is at

   least 10 but less than 30% of the radial length (AW)

   of the whole peripheral portion, the ratio of the radial

   length of the corner part to the step part is from

   0.8:1 to 1.7:1, and the height (rx) of the corner part

   above the plane of the step part is from 55 to 65% of the

   height (DY) of the top of the corner part above the plane

   of the central panel.

   8. A method according to claim 7 wherein the radial

   length of BC is 15 to 25% of AW.

   9. A method according to claim 1 substantially

   as hereinbefore described with reference to and as

   illustrated in Figure 4 of tie accompanying drawings.

   A container closed by a method claimed in any

   one of claims 1 to 6.

   11. A container closed by a method claimed in

   claim 7, 8 or 9.

   12. A method according to any one of claims 1 to

   6 wherein the radial length of the step part (BC) is

   to 70% of the radial length (AW) of the whole

   peripheral portion, and the height (DX) of the corner

   part above the plane of the step part is from 20 to

   of the height (DY) of the top of the corner part above

   S2- the plane ote the central panel.

   13. A method according to claim 12 whereinthe radial -length of BC is 40 to 60% of AW.

   14. A method according to claim 1 subst anti dJly as hereinbefore dc -cribed with reference to and as illustrated in F-.gure 2 or 3 of the accompanying drawings.

   A container closed by a method claimed in claim 14. 16_ *Th partsg, aknts, steps a.nd to or indicated in the specification a l,'aims and/or

   drawings of this appli cati Indilvidually or collectively,

   and any and a oni-mbinations of any two or more of said

   lements, e~rt steps or fc@*turcc.

   Dated this 26th day of May, 1975.

   W.R. GRAC CO. By its Patent Attorneys, U DAVIES COLLISON

   0

   L

   1Ik1V~ I V II