2 1 7 0 3 , 7 6 9 United States Patent Office Patented Mar. 8, 1955. 2,703,769 MEETROD OF MAKING MULTIEPLE-GORE BALLOONS 5 Henry J. Stinger, Wayzata, Raymond 1. Hakomaki, Minneapolis, and WilRam F. Huch, St. Paul, Minn., assignors to General PJUls, lue., a corporation of Delaware 10 Application May 9, 1950, Serial No. 160,973 13 Claims. (Cl. 154-85) This invention relates to balloons and more particu15 larly to a method and apparatus for manufacturing balloons from tubular material. Balloons are now known in which the baroon body or bag consists of a plurality of gores or sections of light thermoplastic material which are heat sealed to each 20 other at their adjacent edges in order to form a substantiauy gas tight enclosure. In such a balloon, it has beerl customary to make the individual gores of the same size and shape and to cut these gores from a long continuous strip of flat stock, the width of which is slightly 25 greater than the maximum width of the desired gore. It was formerly considered essential that a single layer of flat stock be used in order that the relatively thin thermoplastic material from which the gore was to be cut should be entirely free from folds, creases, or 10 wrinldes which might weaken the resulting gore. Thus it was essential that the two longitudinal edges of a particular gore, which were usually symmetrical with respeet to a longitudinal center line of the gore, should be cut individually from the sheet material. When one 35 gore was cut, another layer of material would[ be placed above the original gore, the gores ordinarily being placed on a table having an edge shaped to correspond to the desired gore pattern, and a second gore would then be cut from the flat sheet. One cut edge of the resulting 40 gore would be heat sealed or welded to the adjacent edge of the other gore. This process would be repeated one gore at a time with one edge of each successive gore being joined to the remaining free edge of the preceding gore, until the desired nuniber of gores had been joined. 4;) Thereafter the remaining free edges of the first and last gores would be seamed together to complete the bag or baroon body. In this process, considerable handling and rearrangement of the individual gores were required at each step of the operation. Each tiine the individual gore sheets were rearranged, it was necessary to align the gore very carefully with the pattern on the table or with the gore to which it was to be joined, in order that the seaming operation could be carried out accurately and without strains on the material. It is one object of the present invention to provide an improved process for the manufacture of balloon bodies of this general type. Another object is the provision of a process of balloon manufacture in which a long tubular strip of thermo6@ plastic material may be utilized. Still another object is the provision of a process in which the necessary handling and rehandag of the gore sections is reduced to a minimum. A further object is the provision of a balloon manu65 facturing process in which all of the layers of material for the individual gores may be laid out and aligned in superimposed relation initially without the necessity of substantial handling and realigmnent as each seam is completed between adjacent gores. 70 A further object is a process in which tubular or folded thermoplastic material may be -utilized, with a folded edge of the material constituting the center line of the resulting individual gores. Another object is the provision of an improved bal75 loon manufacturing table and welding unit combination which facilitates the carrying out of the improved process of this invention with a minimum of rehandling of the gores. Another object is the provision of an iinproved bal50 loon construction table in which provision is made for 2 maintaining the completed gores out of the field of operation of the seaming equipment as later seams are made. Other objects and advantages wiJI be apparent from the fohowing specmcation in which certain preferred embodiments of the invention are described. In the drawings which accompany this specification,. and in which like reference characters indicate like parts, Figure 1 is a side elevation of one form of balloon body which can be made with the method and apparatus of this invention. Fig. 2 is a plan view of an individual gore for construction of the balloon body of Fig. 1. Fig. 3 is a top view of an improved balloon construction table according to the present invention, with a layer of tubular diernoplastic material shown in phantom outline to indicate its proper posilion and alignment on the table. Fig. 4 is a schematic partial sectional view on the line 4-4 of Fig. 3, showing the method of initially laying out the material. Fig. 5 is a view similar to Fig. 4, showing the malerial after one edge of the tubular material has been trimmed to correspond roughly to the desired gore shape. This figure also shows the arrangement of the material in the case where flat material folded on itself to give a single folded edge, is utilized initially in lieu of tubular material. Fig. 6 is a view similar to Fig. 4 showing the initial arrangement of the layers pror to and during the formatioi of the welded seam between the first two gores. Fig. 7 is a view similar to Fig. 6 showing the position of the respective layers during formation of the seam between the second and third gores. Fig- 8 is a similar view showing the arrangement of the layers during formation of the final seal-@i between the free ed-.es of the first and last gores. Fig. 9 is a view similar to Fig. 7 of an alternate form of apparatus for carrying out the process of this invention, and Fig. 10 is a viev7 similar to Fig. 9 of still another embodiment of the apparatus according to the invention. As shown in Fig. 1, one form of balloon body or bag which can be made according to this invention consists of a pliirality of vertically extending gores joined together at adjacent edges to form a gas tight container body. The particular balloon 20 which is illustrated ' Fig. I includes a spherical upper section 22 and a ta lnpered or somewhat conical lower section 24. The individual gores 26 extend vertically of the balloon and are ordinarily trimmed or tenninated in such a manner at their ends as to leave a small top opening 30 and a bottom opening 32. The top opening 30 can be capped subsequently in known manner, while a suitable load ring can be secured to the lower opening 32. A completed balloon of this type is described and claimed in the copending application of Otto C. Winzen, Serial N6. 18,583, ffled AprU 2, 1948, now United States Patent No. 2,526,719, and assigned to the a8signee of the present invention. An earlier method of making such a balloon is also described in the copending application of La Mere et al., Serial No. 18,585, filed April 2, 1948, now Patent Number 2,666,006, and also assi-ned to the same assignee. In Fig. 2 is shown in plan view one of the individual gores 26 from which the balloon body of Fig. I is made. Gore 26 is preferably symmetrical with respect to a lOngitudinal center line indicated by the dotted line 34. The longitudinal edges 28 of the gore 26 taper froin an intermediate portion of maximum width toward the center line at each end of the gore, i. c., at the top 36 and the bottom 38. The top and bottom 36 and 38, respectively, are preferably of finite width rather thaii tapered to a sharp point in order to provide the to-o and bottom openings 30 and 32 of the finished balloon body. It will be apparent, however, that many variations in the particular gore shape and in the size and configuration of the resulting balloon body can be achieved within the spirit and scope of the process and apparatus described below. In Fig. 3, is shown a balloon manufacturing table 40

3 on which gores of the pattem shown in Fi-. 2 can be cut and seamed to, each other. Table. 40. foffows substantially the pattern of a half gore. Thus the table has one straight longitudinal ed,@e 42 which corre.@ponds to the. center line 34 of the conlpleted individ-aal gore. The other edge of the table is provided with a guide edge or strip 44 which fbllows substantially the contour of the desired edge 28 of the completed gore. Thus the guide edge 44 tapers from a point of maximum width at 45 toward the edge 42 of the table at both ends. Thus at one end the portion 46 of guide, edge 44 follows the contour of the upper portion of the des@@'red Pore ed,@e, while at the opposite end the portion 48: of guide ed-e 44 follows the desired contour of the lower Dortion of the gore edge. According to one feature of the present invention, a balloon construction or gore table 40 is provided with a recess or slotted portion 50 just inside the curved guide edge 44 which correspoids to the otiter edge of the f@nished gore. As shown particularly in Fig. 8, this slotted portion 50 can be provided by rnounting the guide strip 44 on a supporting frame 52 which is connected by suitable spacers 54 to the supporting frame members 56 and 58 for the remaining portion of the table 40. As indicated in the figures, the balloon table 40 is also provided with a downwardly offset platform or table surface 60 located outside of and fohowing the same general path as the guide strip 44 which defines one edge of the finished gore. This platform 60 is carried on the same supporting frame 52 which carries the guide edge 44 and is used to support a welding and seaming apparatus as described below. According to the method of the present invention, a strip of tubular material is placed longitudinally on the table 40 as shown in phantom outline in Fig. 3. Thus one folded edge 62 of the tubular material ig placed in alignment with the straight edge 42 of balloon table 40. T'he opposite folded edge 64 of the tubular material extends across the opposite edge of the table beyond the guide strip 44. A length of tubular material is used which is great enough to extend from a position 66 at the head end of the table all the way to the point 68 at the opposite end of the desired gore. Thus the folded edge 62 of material will constitute in effect the center line of the first or lowermost gore to be united according to the present procegs. As shown schematically in Fig. 4, a plurality of strips of tubular material are placed in superimposed relation and aligned with one edge in registry with the straight edge 42 of the balloon table in the manner just described. The number of strips of tubular material will depend on the number of gores desired in the finished balloon envelope. For simplicity of iilustration, the process has been shown in Figs. 4-8, inclusive, with three strips of tubing 74, 76, and 78 in superimposed and aligned relationship. Tbus the lower strip of tubing includes lower and upper layers 70 and 72, respectively. The second strip of tubing 76 which will form the second gore of the balloon includes a lower layer 82 and an upper layer 84 of the thermoplastic material. One edge 80 of thig folded tubular material is aligned with the folded edge 62 of the lower strip 74 and also with the straight edge 42 of the table to constitute the center line of the second gore. Similarly, the third strip of tubular gore material 78 has one of its folded edges 86 in alignment with the straight edge 42 of the balloon table 40 in order to constitutc the center line of the third gore. This third strip has lower and upper layers 88 and 90 of the thermoplastic material which will ultimately constitute the two halves of the resulting gore. Once the individual gore strips have been properly superimposed and aligned on the gore table 40, a series of weights 92 may be placed along the edge 42 of the table to hold the gore sections in proper alignment during tne remainin.- steps of the process. The first step in the conversion of the strips of tubular material into individual gores is illustrated in Fig. 5. In this step, those edges of the tubing at the opposite sfde of the strip from the straight edge 42 of the table are cut roughly to the pattern of the final gore. This cutting or trimming step follows a path spaced slightly outwardly from the guide edge 44, as indicated by the dotted outline 93 in Fig. 3. While it is possible to lay out all the strips initially and then tiim all three tubular gections simultaneously, it is preferred that each strip be trimmed 2,703,769 4 to the condition shown in Fig. 5 as soon as the strip has been positioned and aligned on the table, in order that proper advantage may be takeil of the savings accomnlished i@-i carrying out the process described in the co6 'pending application of Ruch et al., Serial No. 160,972, @@led 1,,Iay 9, 1950, filed of even date herewith, ard assigned lo t'qe assignee of the present invention. Thus in the preferred form of the present invention, the first strip of ttibular material will be positioned on the pattem or 10 gore table with one folded edge in alignment with the straiglit edge 42 correspondir.,g to the center line of the rjiial 5@or@!. --lic opposite ed.-e of the tubular strip will thon b2 tri.-.tiiiied rouehly to the flnal gore shape, after which thc-- ne,@t strip of tubular material will be positioned 15 aiid aligiled and trimmed in the same manner. Successi,;e strips will be similarly process.-d until the desired nuinber of s--ctiors have beeti aligned and trimmed to carry the process to the point illustrated in Fig. 5. Accordin.- to the next step of the process, which is 20 illu.-trated in Fil-. 6, the ctit or free edge of the lowermost layer of the first gore is tracked back out of the way beneath the stack of gores where it will not interfere with the sear-,iiig of the successive gore edges. Thus the edge 70 is tuelced bqck as shown in Fig. 6. 25 At thp. same time, the free ed,-es of all of the upper layer.- of m,@terial ivill be folded back above the stack ag shown in Fig. 6 in order to leave only the upper layer 72 of the first gore section and the lower layer 82 of the second gore section projecting outwardly over the guide so edge 44. These projecting free edges will then be seamed to each other by a welding device indicated generally at 94. The partictilar welding device may be of any desired form depending on the nature of the thermoplastic material, as long as the device provides a strong and gas 35 proof scam between the free edges of the adjacent gores. For purposes of illustration, a heated element 94 has been shovin which consists of an electrically heated re@ sistance wire similar to that described and claimed in the copending Carland application, Serial No. 156,475, 40 filed April 17, 1950, assigned to the same owner as the present invention. Schematic details of stich a welding unit are shown in Fig. 8 in which it will be apparent that the heated welding member 94 is carried on supporting arms 96 mounted on the base plate 98 of the welding 4 device. Rollers 109 which are rotatably mounted on vertical axes at one edge of the base plate 98 are designed to engage the guide strip 44 as the welding device moves along the length of the table on the platform portion 60. One or more slipporting or drive rollers 102 and 50 10,4, engage the table surface 60 to support the base plate 98 and provide for relative movement of the welding device along the table. Since the particular details of the welding unit do not form a part of the invention, the apparatus will not be 55 further described other than to i)oint otit that movement of the heated welding rpember 94 along a path corresponding to the edge of the guide strio 44 will sever the free edges of the thernioplastic material along a similar line and will form a seam or bead of melted thermoplastic 60 material as itidicated at 106 in Fig. 6 between the respective layers. Any scaniing equipment which will pro6 duce a scam of the desired stren!,th and resistance to diffusion can be utilized in the proce5s and apparatus of the invention. 65 Thus, as shown in Fig. 6, the Nvelding member 94 will be moved the length of the table along the guide strid 44 to form a scam 106 between the free edges of layers 72 and 82. Thereafter, these seamed edges and their completed scam 106 will be tucked tbrough the slot 50 so 70 that the seamed edge 106 of layers 72 and 82 hangs downwardly tbrough the slot and is thus located inwardly of the guide strip 44 and out of the way of the next seaming operation. At this time the next pair of free edges to be joined, narnely the layers 84 and 88, will be folded 75 down so as to extend over the guide strip 44. The seaming operation with welding member 94 will then be @-epeated to form -,L furtbc,@r seam 108 betwe--n the reriniiiing free edge of the Fec,,)nd g-)j-c anrl the first fi-ee edge of 80 the third gore. This step of the procp-ss is completely illustrated in Fig. 7. The final steps of the process are sliov@/n ir Fig. 8. As shown in this figure, the second completed seam 108@ is also tucked downwardly through slot 50 where it will be 83 out of the way of the final seaming operation.

]@n this final step, the free edge of the first or bottommost layer 70 of the initial gore is puhed out from under the stack of gores at the side corresponding to the straight edge 42 of the table and is carried up'around the stack so that the initial folded edge 62 is in effect reversed, but it stih aligned with the straight table edge 42. The layer 70 wiU accordingly become the topmost layer of the stack and will be superimposed above the uppermost layer 90 of the top or last gore. Thus the free edges of the layers 70 and 90 wiff project acrosg the guide edge 44 of the table for the formation of the final seam. Movement of the welding member 94 along the guide strip 44 will accordingly result in the formation of the fmal seam 110 between the free edges of layers 70 and 90. As indicated above, only three gores or strips of tubular material have been illustrated for simplicity and convenience. It wiU be apparent, however, that selection of the proper number of gores wfll merely require repetition of the intermediate step illustrated in Fig. 7 until a balloon envelope of the desired shape is obtained. The method can accordingly be utilized for the production of a completed baroon body or envelope of the type shown in Figure 1. An important feature of the process is the fact that the layers of tubular material, when once aligned in superimposed relation, are not substantially disturbed and do not require substantial realigniment throughout the intermediate steps of the process. The only times the material has to be handled to any extent are during its initial alignment, and during the rearrangement of the bottommost layer, in preparation for formation of the final seam. As pointed out above, the process can only be used withthermoplastic sheet material which is not weakened or cracked at its folded edges, inasmuch as one of these folded edges is utilized as the center line of the completed gore. Tubular thermoplastic material is ordinarily supplied in relatively large rolls, so that the folded edges of the tubular strip are substantially creased during storage. After such creasing and storage, many types of thermoplastic material would be cracked or weakened to an extent which would make the material unsuitable for use in the present process. Polyethylene tubing, however, has been found to possess extremely high resistance to flexing and creasing. Such material, when processed according to the present 'mvention, shows no substantial weakness or permeability at the center lines of the individual gores where the material was folded or creased during storage on its supply roll. Consequently the process of the present invention is particularly adapted to the construction of balloons from tubular polyethylene material. As suggested above, it might be possible to utilize material in the present process which has only one folded edge between its upper and lower layers. In such a case, the process could be started by stiperimposing the folded edges of the respective strips above the proposed center line of the desired gores as illustrated in Fig. 5, and then continuing the described process from that point. To date, however, thermoplastic material of the type suitable for bauoon manufacture has not been supplied in folded form corresponding to the layers illustrated in Fig. 5. The problem of starting with flat sheet material of double this width, and folding it to the form shown in Fig. 5, is believed to involve additional labor. Therefore the preferred form of the present process utilizes tubular material of the type shown initially in Fig. 4, although it should be remembered that the process can be used advantageously whenever material is readily available initially in the form shown in Fig. 5. An alternate form of apparatus for carrying out the present invention is iuustrated in Fig. 9. This apparatus includes a balloon table 140 similar to the table 40 of the previous embodiment. One edge 142 of the table is straight and corresponds to the center line of the desired final gore. The other edge 144 follows the contour of the outer edge of the gore but is spaced inwardly somewhat from the exact location of the gore contour. In other words, the total width of the table from edge 142 to edge IL44 is slightly less than half the width of the desired gore. In this table a platforni 160 is provided for the welding unit and this platform 160 carries a guide rail 162 parallel to the contour of edge 144. A notched supporting roller 164 is provided on the welding unit to guide the unit in the desired path. The welding Linit includes a heated member 194 carried by supporting arms 196 on a suitable base 198. The guide roller 164 as weli as ad itional supportin- rollers 166 are rotatably mounted on the base 198. M'ovement ol- the welding device along the rail 162 will accordingly resiilt in movement of the welding mei-nber 194 along a path parallel to the guide edge 144. The path of welding niember 194 corresponds exactly to the contour of the outer gore edge. Since this path is spaced outwardly from the edge 144 of the gore table, a space will be provided in which the layers of 10 material which are first seamed to each other can hang downwardly out of the way of the welding operation which is applied 'co s-,ibsequent layers. The process steps previously described will be equally applicable in connection with the apparatus of Fig. 9. 15 Similarly, in Fig. 10 ' another embodiment of the apparatus is shown. Here, the gore table 240 has a straight edge 242 corresponding to the center line of the gore and a curved edge 244 corresponding to the contour of the outer edge of the gore. The welding member 294 is 20 carried by arms 296 on a platform 298 on which are mounted guide rollers 300 to engage the edge 244 of the table, as well as supporting rollers 302 and 304 to carry the welding unit along the platform 260. In this case the base plate 298 of the welding unit extends inwardly above 25 the table edge 244 and is spaced above the top of tlle table portion 240 a distance sufecient to accommodate all of the welded layers of thin thermoplastic sheet material. Thus the layers 72 and 82 and the welded seam 106 which has previously been formed may rest directly on the top of 30 table 240 as shown in Fig. 10, while the next two layers 84 and 88 are supported on the platform 306 of the weldoperation. With the the welding process pred out in the same gen35 The preferred form of the process described in connection with Figs. 4 to 8 involves the initial laying out on the balloon table of enough strips to form all the desired gores of the final balloon. Thus all the folded edges 40 corresponding to the gore centerlines are aligned initially with the straight edge of the table, and this alignment is maintained throughout the successive intermediate seaming steps. According to an alternate form of the i-,ivention, it is 45 possible to alternate the steps of laying out and sealing the strips. Thus the first two tubular strips would be laid out and aligned as indicated. After seaming the upper layer of the bottom strip to the lower layer of the second strip, the operator would then lay out a third sl@rip. After 50 proper alignment of this third strip, its lower layer would be seamed to the upper layer of the second strip. These steps would be contintied with alternale layin.- out and sealing operations until the desired ntimber of gores have been united. 65 According to the fore.-Oing specification, a method and apparatus for balloon construction have been described which accomplish the objects set forth at the beginning of the application and which make possible more economical production of balloon bodies of thermoplastic material. 60 Since minor variations and changes in the exact details of construction will be apparent to persons skilled in this field, it is intended that this invention shall cover all such changes and modifications as fall within the spirit and scope of the attached clairns. 65 We