AU525933B2 - Rotationally moulded container with integral outlet opening flange - Google Patents

Description

525E APPLiCATION APPLICATION

ROT IsI

hereby apply for t'l IMPROVEMENT

which is described AC flV38flS VE961-SrnIVONVIS NOIIVN IVH-O 1su1 NoaifOS8 AdOOOMWJ The application is a or similar protectic 00*

olat in Israel 0I

0 oil 31st Jul

-1 M giI ill 0

111 APIPLICAT. 14 ACC~rl' m "11, 0*

\l Iv't 4.00 0 0 4,

04. o 4,4.4,

a I Little Collins Sb 4, 00 04,

Dated this 4, 4.4. S 4,4,4.

4,4. 4. 4.~ a

To:- THE Co Davies 4

fm0-

c o m m

-2 (11) AU-B-48 365/79

V 3 AUSTRALIA SATENTS ACT 19592

APPLICATION FOR A PATENT (CONVENTION OR NONS

We ROTO1'LAS LTD. an Israeli company. of TE U trih1. ente r Talpi~t, Jerusa m? Israel

65/79 6~ hereby apply for the grant of a Patent for an invention entitled J' 0 "IMPROVEMENTS IN ROTATIONALLY MORLDE COTI

which is described in the accompanying xjVkseiiain

o The application is a Convention application and is base4, on the application(s) for patent .0 p or similar protection made 0

0 C, SIsrael

00 00 on31st July, 1978 under No. 55251 t

o o o o~ 0 C. 0 0 00 under No. 000

00~0

APPLACO; it4p~~.~DAD A ET F .11

*0 00 0 00

00 0* O The address for service is care of DAVIES COLLISON, Patent Attorneys, of 0 1 Little Collins Street, Melbourne, in the State of Victoria, Commonwealth of Australia. ~4.

F p

Dated this 21st day of June, 19 79

0

0p to

00 S 0 S..

(a ember ofi* the* -fir"m *of.DAVI*ES COLLISON for and on behalf of the Apqlicant)

To:, THE COMMISSIONER OF PATENTS Davies Colison, Melbourne and Canberra.

ALVTRALIA Patents Act 1952 Fl

DEICAIATION IN,SUPPORT OF A COMMNTON APPLICATION FOR A PATENT OR PATENT OF ADDITION In support of the Convention application made for a patentUM potent of for an invention entitled IMPROVEMENTS IN ROTATIONALLY MOULDED CONTAINERS 48

of RO1TPLAS .LTD INDUSTRIAL CENTER TA.LPIT......JERUSAL.EM.....S!RAEL do solemnly and sincerely declare -as follows:- 1. Ia= the appmeiz o t Re aete di (or, in the case of an application by a body corporate) authorized.0.......by am auhamze e....pplicantplian for the patent to make this declaration on its behalf. 2. The basic application as defined by section 141 of the Act was made in....ISRAZI on the

day of MY 197A..., by. 9ORKLA 3- I am the actuiaa inventer of the kvmen n efcrrcd to in the basie appiieftfien. (or, where a person other than the inventor is the applicant)

I...SRAELI.... CITIZEN... I

S.T.RUET .sRU.SAL.M4~. J A

is the actual inventor of the invention and the facts upon which the.. AM CANTJsetld to make the application are as follows:- The Inventor has asf entitled'F....... Applcto an roiyrghts to the Applicantby Assiqnment dated 31 Jul yff 4. The basic application referred to in paragraph 2 of this Declaration was the first application made in a Convention countsy in respect of the invention the subject of the application. (or, where a request is made under section 142AA of the Patents Act 1952, for an earlier appiication made in a Convention country to be disregarded) 4.-(L.)The ba&i application rferrfed to in pwaaraph 2 of thie Doelexation was nt firs~t-~~e4e made in a Convention country in respect of the; invenion the subject of theappli atI-. An earlier applicatioa in respect of the invention the su .*ef-Ilhe application was made ip on A request has been made tQ n er section li42M of the Patents Act 1952 to disregard that eartler application. ParagroP&Mewfaeiai sw w;hei J4.i..it A#~i "UFlAMMI.

Except as stated in this paragraph, the basic application referred to in paragraph 2 of this Declaration was

the tst'application made in a Convention country in respect of the invention the subject of the appication.

Declared day.o...M

G eneral

To: (Sign ure of eclarant.) Maflaer

Tim Commiss5toNE1oF PATENTS.

(IMORTANT.-Cross out MinspUcAble words In ubWr. Form.)

11768/77 C. 5.Tuimiwow Acting commoiweath overrntent Printer

La-

separately, The present invention relates to plastic containers nq flanze by

A Ti IA PATENT ABRIDGMENT AD (11) AU-B-48 365/79

(54) ROTATIONALLY MOULDED CONTAINER (71) ROTOPLAS LTD (21) 48 365/79 525 933 (22) 25.6.79 (24) 31.7.78 (31) 55251 31.7.78 (33) IT (43) 7.2.80 (44) 9.12.82 (51)2 B29C 1/14 B29C 5/04 (72) JOSEPH BRAVERMAN (74) DM (56) 00 207/75 484 707 B29C 27 368/67 428 087 70.1

(57) Claim 1. A mould for rotationally moulding cylindrical containers having a bottom, top and mainwalls portions with an integrally moulded outlet opening flange projecting from a side-wall of said main-wall portion, said mould comprising a main-mould-section for moulding the bottom and the main-wall portions, and a lid-mould-section for moulding the top wall portion of the container, the lid-mould-section being separable from the main-mould-section so that the completed container can be extracted therefrom, characterized in that the main-mould-section is provided with a hollow flange-moulding-section radially projecting from the main-wall-section by a predetermined length which is less than the total diametrical cooling-shrinkage of the main-wall portion after the rotational moulding prucess is completed, thus allowing the extraction of the container with integrally formed flange from the main-mould-section.

/2

ni 46* 2

*116/64/10

I:

(11) A-B-48 365/79 2

Claim 8. A method of rotationally moulding a container having an integral outlet flange projecting from a side-wall of the container comprising the steps of' introducing mouldable material into a mould having a recess in one side-wall thereof for forming said flange, cooling the material, removing the moulded container in a direction geherally parallel to said one side-wall after said flange clears said recess on shrinkage-contraction of the container and flange.

*116/64/15

Davies Collison, Melbourne and Canberra.

s C f T Oi,- s^ J3 VA C O MMO N W E A L T H OF L3A3

PATENTS ACT 1952

COMPLETE SPECIFICATION

(Original)

FOR OFFICE USE

483 6 5/79 Class Int. Class

Application Number: Lodged;

Complete Specification Lodged: Accepted: Published:

Priority:

Related Art:

t Name of Applicant: ROTOPLAS LTD.

Address of Applicant: Industrial Center Talpiot, Jerusalem, Israel

Actual Inventor(s): JOSEPH BRAVERMAN .4 .4 .4t

Address for Service: DAVIES COLLISON, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000

Complete specification for the invention entitled: "IMPROVEMENTS IN ROTATIONALLY MOULDED CONTAINERS"

The following statement is a full description of this invention, including the best method of performing ,t known to us

1

~UI-~~ST"IIC I I Illr""~l*r~'-riir*r"- rrr- ~Lly.

La-

The present invention relates to plastic containers

having integrally moulded projections,,and, more specifically,

to moulds for rotationally moulding containers having integrally

mounded flanges.

In the art of moulding plastic containers there has always

existed the need for providing projections from their side-walls,

;uch as flanges, having sufficient length for attaching thereto

valves, hoses, spigots, etc.

Such plastic containers are readily prepared by various

moulding techniques such as 'low moulding, injection moulding

and others, wherein the mould sections are designed to open

along an axis bisecting the flange, thus permitting removal of

the flanged container from the mould.

In the case of rotational moulding, however, when moulding

large cylindrical containers of about 0.5 meter diameter or

more, the mould design is generally such that the opening of

the mould is provided at its top, namely normal to the axis

of the container. Such a mould is illustrated in Figure 1,

where X X is the plane along which main-mould-section 1 and

!0 lid-mould-section 2 are separated through a hinge connection

H. Moulds of this type are easier to manufacture since a

shorter circumference has to be matched and fewer bolts have

to be opened and closed to hold the mould sections together.

Such moulds were thus regarded unsuitable for producing

containers having projections at their side-walls, since it would have been impossible to extract them through the open lid 2. The provision of flanges had therefore been effected separately, by forming a hole at the side-wall and attaching a flange by heat welding, gluing or snap-in-place means.

This method has of course many drawbacks.

Integrally formed flanges had in fact been applied to

rotationally moulded containers by specially designed, most

expensive moulds, such as those illustrated in Figures 2 and 3.

In Fig. 2, mould-sections 3 and 4 were provided, hinged

along plane Y Y which bisects flange 5 (as in the above-

mentioned blowing or injection-moulding techniques) in a di-

rection normal to the axis of the mould.

Similarly, Fig. 3 shows two symmetrical mould sections

6 and 7, separable along plane Z Z which, again, bisects a

flange 8, but in the axial plane of the mould rather than

normally to such plane as in the former example.

Both of these prior art devices were rejected by manu-

facturers as being inconvenient and non-economical.

In acordanc with one aspet of the invention ther provided a mould for rotationally moulding container aving

an integral outlet opening flange projecting f a side-wall of the ,ontainer, said mould comprising amain-mould-section

and a lid-mould-section for retri ng the completed container therethrough, characterize n that the main-mould-section is

provided with a cavi for forming therein said flange, the

depth of the ity being less than the cooling-ishrinkage

rate o e container in the projecting direction of the -c

I.:19~-I.ILL~I

-2a-

According to one aspect of the present invention

there is provided a mould for rotationally moulding

cylindrical containers having a bottom, top and main-

walls portions with an integrally moulded outlet opening

flange projecting from a side-wall of said main-wall

portion, said mould comprising a main-mould-section for

moulding the bottom and the main-wall portions, and a

lid-mould-section for moulding the top wall portion

of the container, the lid-mould-section being separable

from the main-mould-section so that the completed

container can be extracted therefrom, characterized in

that the main-mould-section is provided with a hollow

flange-moulding-section radially projecting from the

main-wall-section by a predetermined length which is

less than the total diametrical cooling-shrinkage of

the main-wall portion after the rotational moulding

process is completed, thus allowing the extraction of

the container with integrally formed flange from the

main-mould-section.

According to a further aspect of the present

invention there is provided a mould for rotationally

moulding containers having an integral outlet flange

projecting from a side-wall of the conta±jxer, said

moulding having a cavity in one wall thereof the

depth of the cavity being less than 1.5 to 8% the

distance between said one wall and the opposite wall

of the mould whereby the container can be removed from

the mould in a direction generally parallel to said

-2b-

one wall.

According to a further aspect of the present

invention there is provided a method of rotationally

moulding a container having an integral outlet flange

projecting from a side-wall of the container comprising

the steps of introducing mouldable material into a

mould having a recess in one side-wall thereof for

forming said flange, cooling the material, removing

the moulded container in a direction generally parallel

to said one side-wall after said flange clears said

recess on shrinkage-contraction of the container and

flange.

KY

hli m~ngpua~irsar~i~~n~~h~,~~p i I.liiliY:LII~LL~~L 1~9

Thus, for example, polyethylene, depending on the part-

icular type, shrinks in the mould upon cooling in the order

of 1.5% to about Rotational moulding grE.des shrink

about Assuming an average of 4% shrinkage rate, it

would be possible, according to this invention, to mould

containers with integral side-wall flanges of maximum flange

lengths as shown in the following table:

Container Diameter (Meters) Flange Length

D 0.5 S

While the above-described mould is quite suitable for

preparing relatively large diameter containers with integrally

moulded flanges on their side-walls., it has been found that

in practice, in some instances, even after cooling and suffic-

ient shrinking, removal of the container from the mould was

difficult because the flange tends to stick to the cavity of

the mould (usually because of inadequate mould-release agents)

and there was no access to that location for releasing the same.

It is therefore suggested to have the said cavity formed

of a releasably mountable cup-like member.

Through the use of a releasably mountable cup-like flange-

forming member according to this aspect of the invention, the

following advantages are achieved:

~L a. Cooling of the flange and surrounding area is accomplished more qaickly; b. access to the flange is provided from outside the mould to help during removal of the container from the mould, in that the flange can be pushed into the mould; and c. the closed end-wall of the flange can be cut-out before removal of the container from the mould.

The invention will be better understood, and the advantages

gained by its use more fully appreciated in the 'ight of the

following detailed description of a few embodiments thereof,

given by way of example only with reference to the accompanying

drawings, wherein:

Figures 1-3 illustrate prior art moulds as above described;

Figure 4 is one embodiment of a mould provided with an

integral cavity according to the general teachings of this

invention;

Figure 5 shows a releasably mountable cup-like member

attached to a mould according to one preferred embodiment of

this inention;

Figure 6 is another embodiment of the cup-like member;

and

Figure 7 is still another embodiment of the cup-like

member.

The mould of Fig. 4 comprises as known with respect

to the prior art moulds of Fig. I a cylindrical main-mould-

section 101 of a diameter D, and a hinged lid-mould-section 102.

L I

Where the integral outlet flange is to be located, there

is provided a cavity 109, formed by a cup-like hollow projection

110 bulging from the mould wall 101.

The measure is such that, after cooling-shrinkage of

moulded container 111 together with its flange 112 and closed

end-wall 113, the flange 112 would no longer be accommodated

within the cavity 109, thus allowing the retrieval of the

container through the open lid 102 (see broken line position).

In Fig. 5, a cavity 114, for forming therein an integral

flange (not shown) by the rotational moulding process, is

defined within a cup-like member 115. The merber 115 is

releasably attached to the mould wall 101 by stud-bolts 116

projecting from the wall 101, around opening 117, and passing

through complementary bore-holes 118 provided in an annulus 119

radiating from the open end of the member 115.

Again, the depth of the cavity (or the length of the

flange) S is such that after the shrinkage of the container,

the moulded flange (not shown) would be located outside the

cavity 114 and the opening 117.

In order to still further facilitate the retrieval of

the container from the mould 101, the member 115 would be

disconnected from the mould by releasing the bolts 116 so that

the end-wall (113 in Fig. 4) can be reached from the outside and

pushed-home and upwardly if necessary; such end-wall may be cut away already before the extraction of the container, thus

shortening the flange to some additional extent, since in any

event it would be removed prior to use of the flange as an

outlet of the container

diaim

1\P~nri--

6

The alternative embodiment of Fig. 6 comprises a similar

cup-member 120, attached rather than to the mould-wall 101

proper to a mounting disc 121 flaring from the open end of

a short cylindrical collar 122.

Reference-is now made to the embodiment of Fig. 7,

wherein the releasable cup-like member concept is extended

to include the formation of a recessed flange, by means of

which the useful length of the ultimately formed flange may

be further increased.

As in the former embodiment of Fig. 6, there is provided

in the nould wall 101 an opening 123, with a cylindrical

collar 124 and mounting disc 125 for the fastening thereto,

by boltE. 126, a releasable flange-forming member generally

indicated 127.

The member 127 comprises a central cup-like portion 128,

an annu:.ar collar 129 extending around the open end of the

portion 128 at an acute angle a as shown, a cylindrical

portion 130 fitting into the collar 124, and an annulus 119'

which is complementary to the disc 125.

Tho relative dimensions of the member 127 are such that

a rotat;onally moulded outlet flange 131 will become located

in a recessed position with respect/wall 132 of the moulded

container 133. Consequently, the above-mentioned shrinkage-

determi.ed flange-length limitation would apply only to the

section marked 131' but not to the remaining recessed

section 131" of the flange 131. The effective or useful

length for supporting a spigot or rubber hose (not shown)

Liar is thereby increased beyond the shrinkage length S which is a 101 function of the container Diameter D. I of This recessed outlet opening flange method is therefore

particularly useful with respect to containers of small diameters or where a low shrinkage rate of 1.5% would result

in a too short flange, as above explained.

It goes without saying that all the advantages of the ay former embodiments are retained, even to a lacger extent,

namely the quick cooling and accessability of the flange ided for facilizating to removal of the container Erom the mould.

Those skilled in the art to which this invention 0, pertains will appreciate that many variations and modifications y thereof may be applied without departing from the scope of

the invention as defined in the appended claims. 128,

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:hat Lted Led Lge-

:he is a ore

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A1d.

-ations

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Claims (1)

1. The claims defining the invention are as follows:-

   1. A mould for rotationally moulding

   cylindrical containers having a bottom, top and main-

   walls portions with an integrally moulded outlet open-

   ing flange projecting from a side-wall of said main-

   wall portion, said mould comprising a main-mould-section

   for moulding the bottom and the main-wall portions, and

   a lid-mould-section for moulding the top wall portion

   of the container, the lid-mould-section being separable

   from the main-mould-section so that the completed

   container can be extracted therefrom, characterized in

   that the main-mould-section is provided with a hollov

   flange-moulding-section radially projecting from the

   main-wall-section by a predetermined length which is

   less than the total diametrical cooling-shrinkage of

   the main-wall portion after the rotational moulding

   process is completed, thus allowing the extraction of

   the container with integrally formed flange from the

   main-mould-section.

   2. The mould as claimed in claim 1 wherein

   the flange-moulding-section is integrally formed with

   a side-wall of the main-mould-section.

   3. The mould as claimed in claim 1 wherein

   the flange-moulding-section is formed by a hollow cup-

   like member releasably mounted on a side-wall of the

   main-mould-section, covering an opening formed in said wall.

   4. The mnould as claimed in claim 3 wherein said opening is encircled by an outwardly projecting flanged cylindrical collar, said member being flanged for fastening thereof to the flange of the collar by

   bolts.

   The mould as claimed in Claim 3 wherein said cup-like membr-- comprises an annular collar extending around the open end of the member at an acute angle with respect to the walls of the member so that when mounted on the mould side-wall, at least a portion of the member projects into mould.

   6. The mould as claimed in claim 5 wherein said annular collar is extended by a cylindrical portion and said opening is encircled by an outwardly projectinj cylindrical collar, the member being fastened to said cylindrical collar by bolts engaging complementary mountitnq discs.

   7. A mould for rotationally moulding containers having an integral outlet flange projecting from a side-wall of the container, said mould havin~g a cavity in one wall thereof the depth of the cavity being less than 1.5 to 8% -11he distance between said one wall and the opposite wr.11 of the mould whereby the container

   L~J can be removed from the mould in a direction generally parallel to said one wall.

   8. A method of rotationally moulding a

   container having an integral outlet flange projecting

   from a side-wall of the container comprising the steps

   of introducing mouldable material into a mould having

   a recess in one side-wall thereof for forming said

   flange, cooling the material, removing the moulded

   container in a direction generally parallel to said

   one side-wall after said flange clears said recess

   on shrinkage-contraction of the container and flange.

   9. A mould substantially as hereinbefore

   described with reference to Figures 4 dto 7 of the

   accompanying drawings.

   DATED this 20th day of September, 1982

   ROTOPLAS LTD. by its Patent Attorneys DAVIES COLLISON

   (Ul' *'it B itera.t^.Ali- jE~Saf^B