US2526719A - Balloon construction - Google Patents

Description

Oct. 24, 1950 o, c, WINZEN 2,526,719

BALLQON CONSTRUCTION 4 Sheets-Sheet 1 Filed April 2, 1948 INVENTOR 57 OTTO .C. WINZEN 36 BY M (i MTORNEY O :t. 24, 1950 o. c. WINZEN 2,526,719 v BALLOON cons 'mucnou Filed A ri1 2. 194s t 4 Sheets-Sheet 2 IN VE N T0 OTTO C. W NZEN' BY fl g ATTORNEY Oct. 24, 1950 c, wmz 2,526,719

BALLOON cous'mucnou 4 sneetsksnebia Filed April 2. 1948 INVENTOR OTTO c. INEN.

g ATTOR/VEY Oct. 24, 1950' o. c. wmzEN 2,526,719

I BALLOON CONSTRUCTION Filed April 2; 1948 4 Sheets-Shea} 4 mvE/vmk OTTO C. NZEN NE-Y Patented Oct. 24, 1950 UNITED BALLOON CONSTRUCTION Otto C. Winzen, Minneapolis, Minn., assignor to General Mills, Inc., a corporation of Delaware Application April 2, 1948, Serial No. 18,583

24 Claims. (Cl. 244-31) 1 The present invention relates to balloons and more particularly to high altitude or stratosphere balloons, capable of carrying a substantial payload.

Defects and disadvantages of the prior art In balloon constructions in the prior art it has been customary to provide first a gas proof bag of rubberized fabric which serves to retain the lifting gases and a load net superimposed over the bag or having a catenary ring to which load lines are connected for supporting the gondola. The gas bags of such balloons have been heavy and the extra weight of the net and load lines has been so great that it has been impossible to obtain successful high altitude performance with balloons of this type.

While some attempts have been made to eliminate the catenary ring and load net construction, such attempts have been unsuccessful because no method of construction has been available which would permit the use of materials for the bag which would be at the same time gas proof and light in weight, and would possess suflflcient strength to permit the elimination of the outer net or catenary rings.

Objects of the present invention With these defects of the prior art in view, it is accordingly one object of the present invention to provide a balloon construction which is capable of sustained flight at extremely high altitudes.

It is another object to provide a balloon of novel construction in which the catenary ring and load net of the usual type have been eliminated.

Still another object is the provision of a balloon having gores of gas proof material which is in itself too thin to bear the necessary load, said- 2 a load ring and load lines to the bottom of such a balloon.

Another object is the provision of an improved closure and sealing cap for the top of such a balloon.

Other objects and advantages will be apparent from the following specification in which a detailed description of a balloon embodying the improvements of the present invention has been g ven.

In the drawings which form a part of this specification and in which like reference characters indicate like parts,

Figure 1 is a perspective view of a balloon according to the invention.

Fig. 2 is a plan view of one of the gores of such a balloon.

Fig. 3 is a schematic sectional view showing a step in the joining of the gore sections together.

Fig. 4 is a sectional view of a joint between two adjacent gores.

Fig. 5 is a sectional view similar to Fig. 4 with a reinforcing tape applied to the seam according to the present invention.

26 Fig. 6 is an enlarged partial perspective view of the lower section of the balloon showing details of the connection of the load lines.

Fig. 7 is an enlarged perspective of the area designated as A in Fig. 6.

Fig. 8 is a sectional view on the line 8-8 of Fig. 7.

Fig. 9 is an enlarged view of the area designated as B in Fig. 6.

Fig. 10 is a sectional view on the line llil0 of Fig. 9.

Fig. 11 is a bottom view of the end of the bal- General construction of the balloon With reference to Figs. 1 and 2, it will be noted that the balloon, designated generally as 2|, in-

eludes an upper portion 22 which is substantially spherical in shape and corresponds to slightly more than half of a complete sphere, and a conical or tapered lower portion 23 which merges tangentially with the upper spherical portion as clearly indicated in the figure. This particular shape is especially adapted to high altitude or stratosphere operation and to the method of construction which is further described in this application. It will be apparent, however, that the details of construction according to the invention are applicable to balloons of different shape.

The balloon consists of a plurality of vertically extending gores 24 of the general shape indicated in Fig. 2. These gores are joined to each other at their edges as described below and the joints are provided with reinforcing tapes 25 which overlap the joints and also serve to carry the load of the balloon.

The gores 24 are made of thin sheet-like material having a weight in the range from .03 to .08 pound per square yard. As suitable materials for this use I have found it possible to employ pliofilm and polyethylene. The polyethylene is particularly suitable for this use because it does not become too brittle at low temperature and retrains nearly all of its original strength after prolonged exposure to sunlight. Any other material which meets the weight requirements, which is gas proof, which is thermoplastic or heat sealable and which has suitable strength and tear ing resistance may be employed for this purpose.

The top of the balloon is provided with a cap or seal 26 which is constituted of a sheet of similar material. of the gores in overlapping fashion by reinforcing tapes 21 and 28 and is in turn overlapped by reinforcing strips 29 which overlie the respective side seams of the gores. This cap construction is described in detail in a subsequent portion of this specification, and it will suifice to point out for the present that the arrangement of the overlapping reinforcing strips and their coincidence with the gore seams provide a continuous series of tapes extending from the top of the balloon down the sides to the bottom. These tapes serve not only to reinforce the seams to which they are applied but also serve the very important function of resisting stretching of the balloon and of distributing the load from the bottom of the balloon throughout the surface of the has itself.

At the lower end of the balloon the tapes 25 and gores 24 are folded outwardly around a suitable balloon ring to be described, the folded portions of the gores 24 and tapes 25 being held in place by additional reinforcing tapes 33 extending horizontally around the lower section of the balloon just above the balloon ring. The additional reinforcing tapes 33 serve to maintain the bottom portions of the gores 24 and tapes 25 in their folded over position as will be clear from the subsequent description.

Load lines designated generally as 34 are conneeted to the balloon ring and are in turn connected to a load ring 35 from which the gondola or other load may be suspended by additional lines 35.

For high altitude or stratosphere flights the balloon construction just described may be made of gores approximately 140 feet in length and 48 inches in maximum width. A total of 58 gores of this types would be used for the complete balloon. Furthermore, a number of such balloons would be suitably connected by lines 36 to This cap is joined to the upper ends a single gondola or load. In certain cases flights of a recorded altitude in excess of 100 thousand feet have been obtained by the use of a balloon of this type connected to a load of pounds.

In other cases where the load requirements do not require so much lifting power, it is possible to utilize a smaller gore and to make the balloon with fewer gores. For example, a 20-gore polyethylene or pliofilm balloon in which the gores have an average length of 40 feet and a maximum width of 40 inches have been employed successfully. The exact number of gores and the size of the individual balloons together with the total number of balloons attached to a single load will be determined by the requirements of a particular flight. In all cases, however, the basic structure of the balloon remains unchanged and follows the principles described and claimed herein.

With the foregoing general description of the invention in mind, the details of the various parts of the construction will now b described.

Side seam construction The side seam construction is shown in Figs 3, 4 and 5. In Fig. 3, for example, a method of joining the edges of adjacent gores 24 and 24 is shown. This method is described fully in the copending application of Frank J. La Mere, Kermit F. Johnson and Otto C. Winzen entitled Method and Apparatus for Balloon Construction, filed of even date and assigned to the same assignee as the present invention, and reference is made to that application for complete details of the method. For purposes of the present application. it will suffice to state that the sheets from the adjacent gores are placed in superimposed relation and are then heat sealed or cut-welded by means of a heated member 38 which cooperates with an anvil member 39. Member 38 is provided with a relatively sharp cutting and welding edge 37 which pinches gores 24 and 24' together and causes the material to fuse into a welded seam 4|. At the same time, said material is severed from the excess or Waste edges 40 of the gores 24 and 24'.

Members 38 and 39 may be of any desired form known in the heat sealing art and as shown in the aforesaid co-pending application are preferably in the form of rollers at least one of which, namely member 38, is heated to the temperature necesary for obtaining the combined cutting and Welding action.

The seal formed between the adjacent gores 24 and 24' is shown in exaggerated section in Fig. 4 from which it is apparent that as the adjacent gores are separated into a fiat relationship such as they would occupy in the finished balloon, the welded seam 4| appears substantially as a small head. This bead, of course, consists of the same material as that of the gores 24 and 24' and in actual fact this bead is almost imperceptible. It forms an integral connection between the adjacent gores.

The load-bearing and reinforcing tapes 25 are placed in overlapping engagement with seams or joints 4| between the adjacent gores 24 and 24' as shown in Fig. 5. In the preferred form of the invention these load bearing tapes are iormed of cellulose material coated with a pressure sensitive or other suitable adhesive. Whereas the material of the gores themselves will not bear any substantial load, the material of which tapes 25 are made must be substantially stronger. A

tape of cellulose acetate or cellophane and having a thickness in the range from .0025 to .004 inch and a width of at least inch has been found to be fully satisfactory for the present pur-- pose.

These tapes 25 extend vertically in overlapping engagement with each joint 4| between adjacent gores 24 and as pointed out above, said strips 25 serve to carry the stresses which the balloon envelope must bear during flight and serve to transmit such. stresses and lifting effects to the lower end of the balloon at which point the load ring construction is arranged for connection of the balloon to the particular load. It will also be clear that the presence of tapes 25 reinforces seams 4| and helps prevent lateral separation of adjacent gores 24 at such joints.

Details of balloon ring construction and attachment As shown in Fig. 2 the bottom 51 of each gore 24 has a definite predetermined width so that such gores do not taper to a point. This bottom width at 51 is sufiicient so that the lower end of the balloon will have whatever circumferential diameter is designed to serve the purpose for which the balloon is made. In Figs. 6 through NJ the details of construction of the lower end of the balloon are shown. A circumferential balloon ring 42, which is preferably hollow as shown at 43, may be made of aluminum or other material which is light in weight but relatively strong. The diameter of balloon ring 42 is such that it will just fit the outside of the lower portion of th balloon. In other words, the gores 24 extend downwardly inside the ring.

With particular reference to Fig. 8, the lower ends 51 of gores 24 and load tapes 25 are then folded up around the outside of the balloon ring 42 so that they lie flat against the outside of the main portion of the balloon and extend upwardly as shown. To hold the upwardly folded end portions of the gores and load tapes in position, bottom tapes 32 similar to load bearing tapes 25 are placed so that they extend around the bottom of the balloon ring and over the tapes 25 and scams 4| both on the inside and outside of the balloon and folded-over ends 51. There will be one of these reinforcing bottom tapes 32 corresponding to each load bearing tape 25 positioned at each seam between adjacent gores.

In order to strengthen this bottom construction and hold th turned-up ends 51 of the gores 24 firmly against the main body of the balloon at points intermediate said tapes, an outer circumferential holding tape 33 is positioned in overlapping engagement above the turned-up ends 5'! of the gores 24, said tape extending circumferentially all round the base of the balloon just above the ring. The ends of tape 33 may be overlapped and sealed together as shown at 50 in Fig. 6. Tapes 32 and 33 are of similar material and it will be noted that tapes 32 extend a substantial distance upwardly alon the gore seams as shown in Fig. 1 in order that the stresses carried by the load bearing tapes 25 are transmitted uniformly and completely to the balloon load ring 42. Since tapes 25 are folded upwardly around the balloon ring just as the gores are folded, as shown in Fig. 8, it will be apparent that as long as the upwardly folded ends of the gores and tapes 25 are maintained in their relative positions without slippage, the stresses careliminate all air from this seam. Ther will always remain a certain air space (designated as 45) which must be properly vented to the outer atmosphere in order that the air in said space may escape when it expands at high altitude. It has been found that unless such air were permitted to escape, it would rupture the joints at a the bottom of the balloon and would thus cause th structure to become weakened or even to separate at this point. In order to vent this air space to the atmosphere, holes 41 have been provided extending through the gores 24 at points intermediate the tapes 25 and joints 4|. Preferably, I have combined these vents with the attaching means for the load lines. This construction is shown in detail in Figs. 9 and 10 from which it will be apparent that an outer reinforcing patch 46 is positioned around the bottom load ring and extended upwardly on both the inside and outside of the gores 24 and circumferential tape 33. Holes 41 extend through patches 46 and through both the inner and outer layers of the gores 24 adjacent the balloon ring 42. Thus an opening is provided which not only gives communication from air space 45 to the atmosphere but also permits attachment of individual load lines 34. These lines 34, which are made of nylon or other material having the necessary strength, resilience, and lightness, are passed through the openings 47 around the load ring and ends 48. Said lines 34 are then secured to the main portions of the lines by whipping as at 49 (Fig. 9) or by other suitable means such as a bowline knot or the like. Patches 46 reinforce the construction of the member at this point and serve to prevent lateral tearing of either the gores 24 or bottom tape 33 due to stresses on the load lines 34.

Details of load lines As shown in Fig. 11 the points of attachment of the various load lines 34 are preferably located at substantially equal distances around the circumference of balloon ring 42 and thes points of attachment are so arranged that they fall between the load bearing tapes 25, joints 4|, and reinforcing bottom load tapes 32. In the balloon shown in Fig. 11, which is a 20-gore balloon, there are 12 of these points of attachment shown, although the exact number and spacing may be varied depending upon the load to be carried, the strength of the individual lines, and other factors. In the construction of Fig. 11, the lines 34 are combined in groups of four for attachment to the load ring 35. As a matter of fact a single line is doubled on itself with the bight 55 (Fig. 12) attached to ring 35 to leave the two ends 34 extending toward the balloon ring. By attaching four of these lines, 1. e., two of the bights 55 as shown in Fig. 12, a group of four lines is obtained. These four lines may be braided together as a single line as shown at 54 for a portion of their length immediately adjacent the load ring 35. This braided portion may be terminated by whipping or by a suitable knot at points 53 from which the lines may be separated into two groups of two lines each as 7 indicated at 52. Finally, at the intermediate points the two lines of each group may be tied together by a square knot or other suitable means, after which lines 34 diverge separately to their respective points of attachment to the balloon ring.

By combination of the lines through braidin and knotting as just described it will be clear that the network of lines at the bottom of the balloon will be simplified and that there will be less chance of the lines becoming entangled dur-- ing storage or launching of the balloon.

Details of cap construction As shown in Fig. 2, the top 56 of each gore 24 does not taper to a point but has a definite predetermined width as shown. Thus, when the gores are assembled by means of the side seam construction described, these upper ends 56 of the gores will leave a small circular opening at the top of the balloon. The capping means by which this opening is covered and made gas tight may be seen by reference to Figs. 13 through 15. In Fig. 13 the circular opening formed by the ends 56 of adjacent gores is covered by a substantially circular cap 58 of the same material as gores 24. This cap is fastened to the upper ends of the gores along two lines. Thus at the extreme ends 56 of the gores, tapes 59 are overlappingly engaged beneath both gores 24 and cap member 58 to form a gas proof joint or seal between these portions. Since tape 59 is on the inside of both gores 24 and cap 58 it will be apparent that gas pressure on the inside of the balloon will force tape 59 firmly against the respective gore and cap members and will maintain the structure in assembled and gas tight relation. Tapes 59 are of the same material as load bearing tapes 25 and are thus adhesively joined both to gores 24 and cap 58 by application of pressure. While it would be possible to provide a single annular tape 59, it is believed preferable to employ a series of tapes which are overlapped with each other as shown at Si in Fig. 13.

A similar taped connection is provided between the outer edge 62 of the cap 58 and the gores 24. This connection is formed by an outer annular tape member 63 similar to tape 59 but positioned on the outside of the balloon envelope as shown in detail in Fig. 14. Tape 63 may also be formed as a single annular tape but is preferably constituted of a series of shorter tapes overlapped as at 64.

Tapes 59 and 63 thus constitute a two-point connection between cap member 58 and the ends of gores 24. In order to strengthen this connection and also provide for reinforcement of the cap member and transmission of its stresses to the load bearing tapes 25, a seriesof top tapes 65 has been provided. These tapes again are similar to tapes 25 and extend across the center 65 of the top of the balloon in alignment with respective load tapes 25 at opposite sides of the envelope. Top tapes 65 thus extend all the way across the diameter of the cap member 58 and overlap the connecting tapes 63 as well as a substantial portion of side or load tapes 25. The ends 61 of top tapes 55 extend downwardly a substantial distance beyond the edges 62 of the cap member 58 in order to obtain a firm connection between these top tapes and the side tapes 25.

It will be apparent from Fig. 14 that, by reason of the double tape connections at 59 and 63, an

air space 58 may remain between the upper ends of gores 24 and the lower portions of cap 58. Here again, it has been found that the air in this space 68 would expand at high altitudes and rupture the joints unless some venting means were, provided. In order to vent this space 68 to the atmosphere and permit expansion of the air in said space, one or more vents 69 should be provided in the cap member 58 as shown in Figs. 13 and 15. Vent openings 69 may be reinforced by suitable patches 18 which are provided with open ings 1| in aligment with the cap vents 69. Patch 10 thus serves to reinforce the vent opening and prevent it from tearing under the influence of escaping air.

It will be apparent that the foregoing cap construction is gas proof and that it provides the necessary strength for the top of the balloon. If the gores were tapered to a point and the side seams 25 were themselves carried across the top of the balloon the construction would be more bulky and uneven and almost impossible to seal in gas tight relationship. Therefore, by provision of this particular cap construction a, means has been provided for the successful utilization of the gore and side seam construction already described. Since the cap member is formed of a single circular piece which lies beneath all the cross tape members 65, it will be clear that the bulk or unevenness of the central point at which these tapes cross can not cause any leakage at this top point as would be the case in the absence of such a cap.

General summary From the foregoing description it will be apparent that a balloon construction has been provided which permits the use of thin plastic materials without the necessity of a, catenary ring or balloon net of the type usually required for large load-bearing balloons designated to operate at substantial altitudes. By provision of a construction in which such light plastic materials may be utilized successfully, this invention has made possible sustained flights with substantial loads at altitudes not previously attainable by standard balloon equipment. The advantages of such high altitude flights with sustained loads for aeronautical research and for atmospheric studies cannot be overemphasized. Since many variations of the exact details of construction shown in the drawings will readily occur to persons skilled in the art in view of the teachings of this application, it is intended that this in-- vention should not be limited by the exact structure shown but only by the scope and spirit of the attached claims.

Now, therefore, I claim:

1. A balloon comprising a plurality of gores of polyethylene heat sealed to each other at their adjacent edges, and reinforcing strips overlying each of said joined edges and attached to the edges throughout the length of the gores by a layer of adhesive.

2. A balloon comprising a plurality of gores of heat sealable thermoplastic material having a weight of not more than .08 lb. per square yard, adjacent edges of sad; gores being heat sealed together with tapes overlapping said joints, these tapes having a weight of not over .01 lb. per linear foot and a tensile strength of at least 1 lb. per tape, and a layer of adhesive joining the tapes to the joints.

3. A balloon comprising a plurality of vertically extending gores of polyethylene heat sealed to each other at their adjacent sides, and

a reinforcing strip of tape overlying each of the,

joints between the acres.

4. A balloon comprising a plurality of vertically extending gores joined to each other at their lateral edges and forming a bag having top and bottom openings, a cap for said top opening, load distributing tapes overlying said joined edges and said cap, and a substantially rigid ring member at said bottom opening to which the tapes are connected.

5. A balloon according to claim 4, having the lower portions of said gores and tapes folded around said ring member and back along the body of the balloon, and means holding said folded portions in place.

6. A balloon according to claim 4, having the lower portions of said gores and tapes folded around said ring member and back along the body of the balloon and a circumferential bottom tape holding said folded back portions in place.

7. A balloon according to claim 4, having the lower portions of said gores and tapes folded around said ring member and back along the body of the balloon and reinforcing tape's extending upwardly from the bottom of said rin and overlying said joined edges both inside and outside the bottom of the balloon.

8. A balloon according to claim 4, having the lower portions of said gores and tapes folded around said ring member and back along the body of the balloon, and reinforcing tapes extending upwardly from the bottom of said ring and overlying said joined edges both inside and outside the bottom of the balloon, and a circumferential bottom tape holding said folded portions and reinforcing tapes in place.

9. A balloon comprising a plurality of gores joined to each other at their adjacent edges to form a bag having a bottom-opening, load distributing tapes overlying said joined edges, a ring member at said bottom opening, said tapes being connected to said ring at spaced points thereon, and load lines attached to said ring at points intermediate said tape connections.

10. A balloon comprising a plurality of gores joined to each other at their adjacent edges to form a bag, load carrying tapes overlying said joined edges, a ring member to which the lower ends of said tapes are connected, and means for attaching a load to said ring.

11. A balloon comprising a plurality of vertically extending gores joined to each other at their lateral edges to form a bag having a top opening, load bearing tapes overlying said joined edges; a cap member closing said top opening and overlapping the upper portions of said gores and tapes and fastened thereto, and top tapes extending over said cap and connected to said load bearing tapes.

12. A balloon comprising a plurality of vertically extending gores joined to each other at their lateral edges to form a bag having a top opening, load bearing tapes overlying said joined edges; a cap member closing said top opening and overlapping the upper portions of said gores and tapes and fastened thereto in gas proof relation, and top tapes extending diametrically over said cap and connected to said load bearing tapes at opposite sides of said opening and cap.

13. A balloon as in claim 11, having a bottom ring to which lower portions of said gores and load tapes are secured, and means for attaching a load to said ring.

14. A balloon according to claim 11, having a bottom ring, the lower portions of said gores and load tapes being folded around said ring and back on themselves, and means holding said folded back portions in place.

- 15. A balloon according to claim 14 wherein said holding means comprises a circumferential bottom tape. I

16. A balloon according to claim 14 wherein said holding means comprises reinforcing tapes extending upwardly from the bottom of said ring and overlying said joined edges both inside and outside the bottom of the balloon.

17. A balloon according to claim 14, wherein said holding means consists of reinforcing tapes extending upwardly from the bottom of said ring and overlying said joined edges both inside and outside the bottom of the balloon, and a circumferential bottom tape overlapping said folded portions and reinforcing tapes.

18. A balloon according to claim 14 having an air space adjacent said ring between the body portions of the balloon and said folded back portions, at least one of said portions having a vent communicating with said air space.

19. A balloon having portions overlappingly joined to each other and providing a space in which air is entrapped, one of said portions having a vent through which such air escapes as it expands at high altitude.

20. A balloon comprising a plurality of gores of heat sealable thermoplastic material heat sealed to each other at their adjacent edges to form gas proof seams, with strips of plastic reinforcing material overlying the said heat sealed seams throughout their lengths, these strips being afiixed to the thermoplastic material by a layer of pressure sensitive adhesive, and a load bearing member to which the ends of the gores, seams and tapes are connected.

21. A balloon comprising a plurality of gores of heat sealable thermoplastic material heat sealed to each other at their adjacent edges with a strip of tape overlying the said heat sealed edges throughout their lengths, this tape affixed to the thermoplastic material by of adhesive.

22. A balloon comprising a plurality of vertically extending gores of heat sealable thermo plastic material having the characteristic of retaining substantial flexibility and strength at low temperatures and under prolonged exposure to sunlight and having a weight of not more than .08 pound per square yard, adjacent edges of said gores being heat sealed together to form gas tight welded seams, load bearing tapes overlying each of the seams throughout its length, and a rigid load ring to which the lower ends of each gore, seamand tape are attached.

23. A balloon comprising a plurality of vertically extending gores of heat sealable thermoplastic material having the characteristic of reand a load ring whose diameter is substantially the same as that of the bottom opening, the lower ends of each gore and seam being attached to said ring.

24. A balloon comprising a plurality 'of versealed to each other at their adjacent sides to taining substantial flexibility and strength at low form gas tight vertical seams, and a load ring to which the lower ends of each gore and seam are attached.

O'I'IO C. WINZEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 529,337 Moore Nov. 13, 1894 2,355,610 Tuggle Aug. 15, 1944 2,392,695 Rohdin Jan. 8, 1946 OTHER REFERENCES P1astics," issue of August 1944, pages 103 to- 107 and 174 to 1'76. (Publication, copy in Div. 67.)

Upper Air Study by Means of Balloons and 10 the Radio Meteorograph," by Akerman and Piccard, Journal of Aeronautical Science, volume IV, No. 8 (June 1937) pages 332 to 337.

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