GB1572400A - Method and apparatus for the manufacture of a container - Google Patents

Description

PATENT SPECIFICATION

( 21) ( 62) ( 31) Application No 11757/79 Divided Out of No 1572399 Convention Application No 629061 ( 11) 1 572 400 ( 22) Filed 5 Nov 1976 ( 32) Filed 5 Nov 1975 in ( 33) United States of America (US) ( 44) Complete Specification Published 30 Jul 1980 ( 51) INT CL 3 C 09 J 5/06 ( 52) Index at Acceptance B 5 K 3 B 5 D 110 112 M ( 54) METHOD OF AND APPARATUS FOR THE MANUFACTURE OF A CONTAINER ( 71) We, RHEEM MANUFACTURING COMPANY, a corporation organised and existing under the laws of the State of Delaware, United States of America, of 767 Fifth Avenue, New York, New York 10022, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly

described in and by the following statement:-

This invention relates to a method of and apparatus for the manufacture of containers for the storage and shipping of materials.

The manufacture of plastics containers by processing moulding material within forming dies has the evident disadvantage of rendering the production of different-sized containers quite costly Thus, moulds of diverse length and volume are required for making each uniquely sized container Waste also occurs since container thickness is not uniformly maintainable in moulding practice, i e containers are unnecessarily thick-walled in corner and like areas Manufacture of containers by other previously proposed techniques is complicated by the need for forming fibrous shells by winding and sealing laminates or joining sections and then applying a sealing lining thereto.

Regarding the reference commerciallyavailable drum, the same is a metal-reinforced plastics drum and its manufacture further entails the need for reinforcing its closure member by radial ribs as above considered.

The present application is divided from patent application No 46176/76 (Serial No.

Claims (1)

1572399), in which we claim a container

comprising an elongate cylindrical shell of plastics material having at least one open end and a closure member of plastics material closing such open end, said closure member comprising a single thickness axially extending cylindrical rim portion encircling and sealingly secured exclusively to the radially outer surface of said shell about said open end, an annular hingedly deformable portion continuous with said rim portion extending radially inwardly from said rim portion to the interior of the shell and a 50 central deformable portion of the closure continuous with the annular portion completing closing of the said open end, said annular portion extending radially and axially inwardly of the open end edge of the shell 55 deformably hingedly to support said central portion and comprising a first part continuous with the rim portion and extending radially of the shell, a second part continuous with the first part and extending axially of and sub 60 stantially parallel to the shell and encircled by the shell and a third part continuous with the second part and extending to a location spaced radially interiorly of and coaxial with said shell, with said central portion being 65 continuous with said third part and having a surface area greater than the planar area encompassed by the juncture of the annular and central portions, the construction being such that the container is resistant to impact 70 by deformation and hingedly unfolding of the annular and central portions.

In that Application No 46176/76 (Serial No 1572399) we also claim a method of making a container comprising the steps of: 75 (a) cutting plastics sheet material into a sheet of predetermined length and width; (b) forming such cut sheet into a hollow shell having a slit extending axially between open ends of said shell and defined by juxtaposed 80 edges of said sheet; (c) sealing said slit to provide an axially extending continuous sealed seam for said shell; (d) forming closure members for said shell open ends by shaping integral plastics material to form a single 85 thickness cylindrical rim portion, an annular hingedly deformable portion continuous with the rim portion extending radially inwardly from the rim portion and a central deformable portion continuous with the annular portion 90 c tn u" 1,572,400 completing closing of the annular portion with the annular portion extending radially and axially inwardly of the closure member deformably hingedly to support the central portion and with said central portion having a surface area greater than the planar area encompassed by the periphery of the central portion; and (e) sealably securing each said closure member at the periphery thereof exclusively to the outer surface of said shell adjacent a distinct one of said open ends thereof, said annular portion comprising a first part continuous with the rim portion and extending radially of the shell, a second part continuous with the first part and extending axially of and substantially parallel to the shell and encircled by the shell and a third part continuous with the second part and extending to a location spaced radially interiorly of and coaxial with said shell, the construction being such that the container is resistant to impact by deformation and hingedly unfolding of the annular and central portions.

According to one aspect of the present invention, we provide apparatus for use in securing a closure member to an open end of a shell to form a container, said apparatus including a first fixture and a second fixture supported coaxially interiorly of said first fixture, said fixtures being supported for relative movement jointly to define an annular space therebetween for, in use of the apparatus, receiving an unbonded assembly of said closure member and said shell and bonding material including magnetizable particles dispersed in plastics, at least one of said fixtures being comprised of separate arcuate segments, first means for displacing said fixtures relative to one another whereby said fixtures apply pressure to said assembly in use of the apparatus, and second means for subjecting such pressed assembly to heat energy, said second means comprising an electromagnetic field generator supported at the pressing periphery of at least one of said fixtures immediate to the pressed assembly and adapted for flexure relative to its supporting fixture, whereby said particles in the bonding material are responsive to such generated electromagnet field to heat said plastics to its fusion point for flowing thereof into intimate contact with surfaces of said shell and said closure member in facing relation to said bonding material.

Another aspect of the present invention provides a method of making a container comprising the steps of: cutting plastics sheet material into a sheet of predetermined length and width; forming such cut sheet into a hollow shell having a slit extending axially between open ends of said shell and defined by juxtaposed edges of said sheet; sealing said slit to provide an axially extending continuous sealed seam for said shell; forming a closure member for one of said shell open ends by shaping integral plastics material; forming an assembly wherein said closure member is disposed in encircling relation to said shell adjacent said one open end and 70 wherein bonding material containing magnetizable particles is disposed about the shell between said closure member and said shell; and securing said assembly by simultaneously applying pressure to said assembly and dis 75 posing a magnetic field generator in immediate juxtaposition with the periphery of said closure member, the pressure being applied in a direction normal to the surface of the shell by means of two fixtures arranged 80 internally and externally of the shell with part of the assembly including the bonding material being located therebetween, thereby heating said material to its fusion point for flowing thereof into intimate contact with said 85 closure member and said shell adjacent said one open end.

The invention will be further evident from the following detailed description given by way of example with reference to the accom 90 panying drawings, wherein:

Figure 1 illustrates schematically the extruding and cutting of shell-forming sheet material; Figure 2 is a top plan view of the Figure 1 95 sheet material formed into a hollow shell with a strip of bonding material disposed in the shell axial seam and subject to the action of fusing apparatus illustrated in section; Figure 2 a is a perspective view showing a 100 manner of energizing the Figure 2 fusing apparatus; Figure 3 is a frontal elevation in section of the completed Figure 2 shell with end closure members therefor; 105 Figure 4 is a top plan view of fusing apparatus for use in securing an end closure member to the shell; Figure 4 a shows tube 40 a of the Figure 4 fusing apparatus removed therefrom; and 1 Mi Figure 5 is an enlarged sectional view of the Figure 4 apparatus as seen from the line VIVI of Figure 4 operative in a fusing operation.

Referring to Figure 1, extruder head 10 dispenses from die lip slit opening 10 a con 11 tinuous sheet material 12 preferably comprised of high molecular weight high density polyethylene Cutting apparatus (not shown) selectively cuts sheet material 12 transversely of its issuing direction to form individual 12 ( sheets 14 having length L and width W The former of these dimensions is controlled by the cutting apparatus whereas the latter dimension may be varied together with sheet thickness T by substitution of extruder heads 12 or changing the die lip opening Opposed side edges 14 a and 14 b of sheet 14 are mitered at an angle of from five to forty-five degrees (Figure 2) and the sheet is then formed into a hollow cylinder As shown in Figure 2, 13 1,572,400 mitered edges 14 a and 14 b are spaced slightly from one another and a strip of bonding material 16 is disposed therebetween Strip 16 is preferably comprised of magnetizable particles, such as iron oxide, dispersed in a plastics base With strip 16 and sheet 14 disposed as indicated in Figure 2, holding fixtures 18 a and 18 b, both comprised of electrically insulative material, are clamped in pressure relation to one another These fixtures support a continuous two-loop coil of axially extending hollow copper tubing 20 which is internally cooled and excited electrically by connection to a radio frequency supply whereby edges 14 a and 14 b of sheet 14 are fused together, applied pressure causing the bonding agent to flow into intimate contact with the facing surfaces of the sheet edges.

Rubber hose 20 a (Figure 2 a) conducts coolant (water) from the right hand tubing 20 in fixture 18 a to the left hand tubing 20 in fixture 18 a At the remote end of such left hand fixture 18 a, the copper tubing conducts coolant and current therefrom to the right hand tubing 20 in fixture 18 b Rubber hose b conducts coolant thence to the left hand tubing 20 in fixture 18 b Switch plates 20 g and 20 h are movable horizontally in Figure 2 a to engage switch plates 20 c-20 fto energize the tubing On completion of the fusing operation, plates 20 g and 20 h are moved vertically to permit axial removal of the bonded shell.

Referring to Figure 3, the above-discussed seaming operation provides a completed container shell 22 having axially-extending seam 22 a End closure members 24 a and 24 b, formed in configuration shown in Figure 3 and preferably of like material to that of shell 22, are disposed in place on the ends of shell 22 with strips 26 of bonding material situated interiorly of the end closure members and exteriorly of shell 22 as illstrated With shell 22, members 24 a and 24 b and strips 26 so arranged, the members 24 b end of the assembly is placed in bonding apparatus as shown in Figure 5 This apparatus has an outer fixture 28 (Figure 4) supported in spaced radially encircling relation to an inner fixture 30, both comprised of electrically insulative material Fixture 28 is of segmented type, including segments 28 a and 28 b each spanning approximately one hundredtwenty degrees and segments 28 c and 28 d, each spanning approximately sixty degrees.

The radially outward surfaces of segments 28 a-28 d engage bladder 32 serviced on demand from a supply of pressurized air through conduit 34 for displacing the segments radially inwardly Rigid outer ring 36 provides a reaction bearing surface for bladder 32 At their radially interior surfaces, segments 28 a and 28 b define grooves 38 (Figure 5) and fixture 30 defines grooves 39 for receiving double loop hollow copper tubes 40 a and 40 b (Figures 4, 4 a).

Tubes 40 a and 40 b are used, as in the case of tubing 20 above-discussed, for applying a radio frequency induction field to unbonded 70 assemblies disposed in channel 42 established between segments 28 a-28 d and fixture 30.

The manner in which the tubing is routed in Figure 4 apparatus is seen in Figure 4 a which shows tube 40 a removed from the Figure 4 75 apparatus Tube 40 a portion 40 a-1 extends into fixture 30 to location L 1 and the tubing then proceeds outwardly toward the viewer of Figure 4 a to tube portion 40 a-2 which extends in an upper groove of fixture 30 clockwise 80 circularly to location L 2 At this location, tube 40 a, proceeds inwardly away from the viewer of Figure 4 a to tube portion 40 a-3 which extends radially outwardly to segment 28 a and thence outwardly towards the viewer 85 to an upper groove in segment 28 a Tube portion 40 a-4 proceeds counterclockwise circularly in such segment 28 a groove to location L 3 and then proceeds inwardly away from the Figure 4 a viewer to tube portion 90 a-5 which proceeds radially inwardly of segment 28 a to a lower groove of fixture 50.

Thereupon tube 40 a extends clockwise circularly in fixture 30 to location L 4 whereupon tube portion 40 a-6 proceeds radially 95 outwardly to a lower groove of segment 28 a and therein to location L 5 At this location tube portion 40 a-7 extends radially outwardly of segment 28 a Fixture 30 and segment 28 a have grooves at locations L 1-L 4 and else 100 where running transverse of and interconnecting their upper and lower grooves to provide for travel of tube 40 a between such upper and lower grooves.

With the unbonded assembly of bonded 105 shell 22, closure member 24 b and strip 26 disposed in channel 42 (Figure 5), conduit 34 is positively pressurized and segments 28 a-28 d press the assembly against fixture 30.

Segments 28 c and 28 d serve to equalize 110 pressure around the circumference of the unbonded assembly Tubes 40 a and 40 b are energized whereby the part of the assembly adjacent the tubes is fused together, the applied pressure causing the bonding agent to 115 flow into intimate contact with the surfaces of shell 22 and end closure member 24 b which face strip 26.

In the embodiment shown in Figures 4, 4 a and 5, tubes 40 a and 40 b each encompass 120 approximately one hundred degrees of arc, mutually spaced by some eighty degrees For a complete bonding operation, the work is rotated and two passes are needed The invention of course contemplates a single 125 continuous double loop tubing assembly whereby the bonding operation may be completed in a single pass mode for joining each closure member to the bonded shell.

Leaf spring 43 between base 44 and the 130 1,572,400 segments urges the segments radially outwardly of channel 42 when bladder 32 is deflated to facilitate removal of bonded assemblies For automated removal of bonded assemblies from the bonding apparatus, ram assembly 46 is slidably supported on sleeve 44 a of base 44 for movement through base opening 44 b into channel 42.

Referring to Figure 3, end closure members 24 a and 24 b include a first (hinge) portion 24-1 having one part 24-la extending axially of shell 22 and encircling the outer surface of the shell and another part 24-lb extending to end locations radially interiorly of and coaxial with the shell The closure members have a second (central) portion 242 continuous with and hingedly supported by portion 24-1 Portion 24-2 is itself preferably bowed axially of shell 22 such that it has linewise surface extent 51 between diametrically opposed ones, e g LA and LB of end locations of portion 24-1 in excess of the diametric spacing 52 between such end locations Closure member 24 a may have bung hole fittings, one being shown at 24 c in Figure 3 As will be appreciated, the closure member hinge and central portions are preferably parts of an integral plastics structure formed by a moulding operation.

Example I The side edges of an extruded sheet of high molecular weight high density polyethylene (HDPE), 38 inches in width, 70 5 inches in length and 0 135 inch in thickness are mitered at an angle of 10 and the sheet is formed into a cylindrical shell as in Figure 2 having a diameter of 22 5 inches and an axially extending slit between the mitered edges A strip of bonding material comprised of HDPE containing iron oxide particles and having a thickness of 0 015 inch and a width of 0 625 inch is placed in the slit and extends throughut the slit length Bonding fixtures are next pressed against the shell slit as in Figure 2 and are energized from a radiofrequency supply to subject the bonding material to an electromagnetic field, heating the material to its fusion point and flowing the material into intimate contact with the mitered edges, thus sealing the shell slit throughout its length.

End closure members are moulded of high molecular weight HDPE in the configuration shown in Figure 3 and have an average thickness of 0 187 inch The line surface extent of the end closure members ( 51 in Figure 3) is four percent longer than the spacing ( 52 in Figure 3) between diametrically opposed end locations of the hinge portion The end closure members are assembled with the shell and with a bonding material strip therebetween as in Figure 3, comprised of HDPE containing iron oxide particles and having a thickness of 0 015 inch and a width of 0 750 inch Bonding fixtures are next pressed against the assembly as in Figure 5 and are energized from a radio-frequency supply to subject the bonding material to an electromagnetic field, heating the material to its 70 fusion point and flowing the material into intimate contact with the surfaces of the end closure members and shell facing the material.

Example 2 75 The side edges of an extruded sheet of high molecular weight HDPE, 13 5 inches in width, 36 5 inches in length and 085 inch in thickness are mitered at an angle of 100 and the sheet is formed into a cylindrical shell as in 80 Figure 2 having a diameter of 11 5 inches and an axially extending slit between the mitered edges A strip of bonding material comprised of HDPE containing iron oxide particles and having a thickness of 010 inch and a width of 85 0.375 inch is placed in the slit and extends throughout the slit length The shell slit is sealed throughout its length in the manner set forth in Example 1.

End closure members are moulded of high 90 molecular weight HDPE in the configuration shown in Figure 3 and have an average thickness of 085 inch The line surface extent of the end closure members ( 51 in Figure 3) is two percent longer than the spacing ( 52 in 95 Figure 3) between diametrically opposed end locations of the hinge portion The end closure members are assembled with the shell and with a bonding material strip therebetween as in Figure 3 comprised of HDPE 10 C containing iron oxide particles and having a thickness of 010 inch and a width of 0 5 inch.

The assembly is secured in the manner set forth in Example 1.

Example 3 10 ' A high molecular weight HDPE shell is extruded in cylindrical form through a circular die slot opening The shell is 13 5 inches in length, having a diameter of 11 5 inches and 085 inch in thickness End closure 11 members with an average thickness of 085 inch are moulded of high molecular weight HDPE in the configuration of Figure 3 except that their line surface extents ( 51 in Figure 3) are equal to the spacings ( 52) between 11 diametrically opposed end locations of the hinge portion, i e central portion 24-2 is flat.

End closure members so formed are secured to the shell in the manner set forth in Example 12 1.

Example 4 A single end closure member of 085 inch average thickness is moulded of high molecular weight HDPE in the configuration of Figure 3 except that their line surface 12 extents are equal to the spacings ( 52) between diametrically opposed end locations of the hinge portion, i e central portion 24-2 is flat.

The end closure member is secured to a HDPE injection moulded one-piece pail 1,572,400 having a height of 13 5 inches, a diameter of 11.5 inches and 085 inch in average thickness, using the bonding method set forth in Example 1.

While the invention has been disclosed by way of particularly preferred embodiments, various changes and modifications thereof will be evident to those skilled in the container, bonding and related arts Where in extruded sheet form the shell axial slit need not have mitered edges nor strip bonding material disposed therein but may have nonmitered edges joined directly to one another by fusion or like techniques or by use of a common backing member joined thereto.

WHAT WE CLAIM IS:

1 Apparatus for use in securing a closure member to an open end of a shell to form a container, said apparatus including a first fixture and a second fixture supported coaxially interiorly of said first fixture, said fixtures being supported for relative movement jointly to define an annular space, therebetween for, in use of the apparatus, receiving an unbonded assembly of said closure member and said shell and bonding material including magnetizable particles dispersed in plastics, at least one of said fixtures being comprised of separate arcuate segments, first means for displacing said fixtures relative to one another whereby said fixtures apply pressure to said assembly in use of the apparatus, and second means for subjecting such pressed assembly to heat energy, said second means comprising an electromagnetic field generator supported at the pressing periphery of at least one of said fixtures immediate to the pressed assembly and adapted for flexure relative to its supporting fixture whereby said particles in the bonding material are responsive to such generated electromagnetic field to heat said plastics to its fusion point for flowing thereof into intimate contact with surfaces of said shell and said closure member in facing relation to said bonding material.

2 Apparatus as claimed in claim 1, wherein said first fixture is segmented and wherein said first means comprises inflatable means situated radially outwardly of and engageable with said segments and rigid means disposed radially outwardly of said inflatable means for defining a bearing reaction surface for said inflatable means.

3 Apparatus as claimed in claim 1 or 2, wherein said second means comprises radiofrequency energizable tubing means supported by at least one of said fixtures and defining an interior hollow for receiving a cooling medium.

4 Apparatus as claimed in claim 1, 2 or 3, wherein said second means comprises radio-frequency energizable tubing means supported by at least one of said fixtures and oi extent less than the perimeter of said assembly and adapted for said flexure relative to its supporting fixture for movement into confronting relation with said assembly in the course of pressing thereof.

A method of making a container corn 70 prising the steps of cutting plastics sheet material into a sheet of predetermined length and width; forming such cut sheet into a hollow shell having a slit extending axially between open ends of said shell and defined 75 by juxtaposed edges of said sheet; sealing said slit to provide an axially extending continnus sealed seam for said shell; forming a closure member for one of said shell open ends by shaping integral plastics material; forming an 80 assembly wherein said closure member is disposed in encircling relation to said shell adjacent said one open end and wherein bonding material containing magnetizable particles is disposed about the shell between 85 said closure member and said shell; and securing said assembly by simultaneously applying pressure to said assembly and disposing a magnetic field generator in immediate juxtaposition with the periphery 90 of said closure member, the pressure being applied in a direction normal to the surface of the shell by means of two fixtures arranged internally and externally of the shell with part of the assembly including the bonding 95 material being located therebetween, thereby heating said material to its fusion point for flowing thereof into intimate contact with said closure member and said shell adjacent said one open end 100 6 A method as claimed in claim 5, wherein the slit is sealed by disposing in said slit material containing magnetizable particles and then subjecting said material to an electromagnetic field thereby heating said 105 material to its fusion point and flowing said material into intimate contact with said sheet edges.

7 A method as claimed in claim 5 or 6, wherein the assembly is secured in a series of 110 successive increments with a magnetic field generator comprised of generator segments, pressure being applied fully circumferentially of the assembly in each such increment with the assembly being rotatively moved between 115 said successive increments for disposing said generator segments in immediate juxtaposition with successive periphery portions of the assembly so as successively to cover the entire periphery of the closure member 120 8 Apparatus for use in securing a closure member to an open end of a shell to form a container, such apparatus being constructed and arranged to operate substantially as herein described with reference to and as 125 illustrated in the accompanying drawings.

J.A KEMP & CO, Chartered Patent Agents, 14 South Sauare, Gray's Inn, London, WC 1 R 5 EU 130 Printed for Her Majesty's Stationery Office, by Croydon Printing Company Limited, Croydon, Surrey, 1980.

Published by The Patent Office 25 Southampton Buildings London, WC 2 A IAY,from which copies may be obtained.