US3393443A - Method and apparatus for making vehicular tube and the like - Google Patents

Description

July 23, 1968 5. P. HURST METHOD AND APPARATUS FOR MAKING VEHICULAR TUBE AND THE LIKE Filed Sept. 3, 1965 3 Sheets-Sheet 1 INVENTOR. GEORGE E HURST ATTORNEYS July 23, 1968 3. P. HURST 3,393,443

METHOD AND APPARATUS FOR MAKING VEHICULAR TUBE AND THE LIKE Filed Sept. 5, 1965 3 Sheets-Sheet 2 INVENTOR. GEORGE P. HURST ATTORNEYS July 23, 1968 G. P. HURST 3,393,443

METHOD AND APPARATUS FOR MAKING VEHICULAR TUBE AND THE LIKE Filed Sept. 5, 1965 3 Sheets-Sheet r- Y ,3 INVENTOR.

l GEORGE P. HURST ATTORNEYS United States Patent 3,393,443 METHOD AND APPARATUS FOR MAKING VEHICULAR TUBE AND THE LIKE George P. Hurst, Palo Alto, Calif. (8454 Meath Drive, Stockton, Calif. 95205) Filed Sept. 3, 1965, Ser. No. 484,867 13 Claims. (Cl. 29-430) ABSTRACT OF THE DISCLOSURE A vehicular tube making apparatus and method in which a tube frame of irregular cross-sectional contour is supported on a planar fiat sheet of metal and is rotated over said sheet and at the same time the sheet is held against and is progressively welded to said sheet to form a tube having the irregular cross-sectional contour of the frame, and which frame will be inside the tube and part of the latter.

This invention relates to an apparatus and method for making a vehicular tube for passage of trains and other vehicles therethrough. Such tubes are commonly employed for sub-surface use to provide underwater passageways for vehicles below the level of bays and rivers.

Tubes for the above purpose are normally preformed on land in similar, tubular open-ended sections that are welded together to form the tubes. The assembly may partially be accomplished on land and completed at the underwater site, but in any case the present invention relates to the forming of the tube sections where the latter are of irregular cross sectional contour transversely of the length of the tube. In the present example, said cross sectional contour is symmetrical at opposite sides of a vertical plane bisecting the tube lengthwise, and the width is greater than the height, having a flat top and bottom wall with the opposite lateral side walls flattened and extending divergently upwardly for a predetermined distance from their junctures with the bottom wall, curved or arched for a distance to join the ends of the top wall, the outer surfaces of said curved portions being convex. The invention is not, however, restricted to this particular contour.

The outside wall of each tube section is of sheet metal; and, where the tube is designed to accommodate several sets of railway tracks for normal sized cars, this outer wall or casing may be up to one-half inch in thickness. The width may be approximately 50 feet, the height approximately 22 feet, and the length about 36 feet. It is to be understood that these dimensions are merely by way of one practical example; and inasmuch as metal only of the tube shell for each tube section, including the permanent metal framing, may weigh up to approximately 60 to 70 tons, the magnitude of the structure may be understood.

Heretofore, in normal practice, horizontal rows of parallel floor beams or ribs in side 'by side spaced relation extending the width of the floor or bottom wall from side wall to side wall would be welded to the sheet of steel that is to form the outer bottom wall of the tube and the sheet metal of each side wall would be bent to the shape of each side wall and then welded to rows of spaced ribs that, in themselves, had been bent to substantially correspondto the contour of the side-wall plates. The same procedure would be followed in forming the top wall. Following the foregoing steps, the side walls would be welded at their lower edges to the end edges of the bottom wall, and the ribs previously welded to the side plates or side walls would be welded at their lower ends to the ends of the floor beams or ribs. The top wall or plate would then be welded at its end edges to the upper edges of the side plates and the top ribs or beams that had previously been welded to the top plate would be welded at their ends to the upper ends of the side ribs.

These conventional steps obviously include the multiple handling of Wall sections and upwardly directed welded operations, including the difiiculties attendant upon attempting to fit the edges of plates and the ends of beams or ribs for welding.

One of the objects of the present invention is to provide a means and method for simplifying and expediting the formation of each tube section of the type described without the dangers and labor involved in the conventional way of forming the tube sections.

Another object of the invention is the provision of apparatus and method that will insure against objectionable irregularities and weaknesses in tube sections that might be hazardous to the public using the tube sections after the tube is completed.

A still further object of the invention is the provision of apparatus and method for producing tube sections more economically than heretofore.

An additional object of the invention is the provision of means for rapidly and accurately Welding an outer shell to a tube frame that is of substantially different dimensions in two dimensions that are at a right angel to each other in a plane at a right angle to the length of the tube that is to be formed 'by the application of said shell to the frame, and which tube is also non-symmetrical in one of said dimensions.

Other objects and advantages will appear in the description and in the drawings.

In the drawings, FIG. 1 is a semi-diagrammatic side elevational view showing the method and means employed. certain parts being indicated in dot-dash line to illustrate different positions of the tube frame during application of the outer shell.

FIG. 2 is a fragmentary vertical cross sectional view showing the plates in position, the base of the apparatus in a position for securement to the plates of the tube shell or casing, where the shell is of a thickness requiring prebending.

FIG. 3 is a fragmentary top plan view of a portion of FIG. 2 in which a portion is broken away to show structure otherwise hidden. The view is substantially along line 33 of FIG. 2.

FIG. 4 is an enlarged, fragmentary cross sectional view taken through the base of the apparatus generally along line 4-4 of FIG. 1, and which view includes a central portion of the tube being formed.

FIG. 5 is an enlarged, fragmentary cross sectional view through an upper portion of one side of the apparatus along line 55 of FIG. 1.

FIG. 6 is a reduced size, side elevational view of the portion shown in FIG. 5 as seen from line 66 of FIG. 5.

FIG. 7 is a side elevational view of the frame to which the outer wall is to be secured, also showing a fragment of the apparatus used for moving the frame.

FIG. 8 is a top plan view of the frame shown in FIG. 7.

FIG. 9 is an enlarged fragmentary cross sectional view through an upper portion of the tube frame including a portion of the apparatus employed, taken along line 9-9 of FIG. 8.

FIG. 10 is an enlarged fragmentary elevational view of a portion of the apparatus employed in the movement of the tube frame.

FIG. 11 is an enlarged, fragmentary sectional view taken along line 11-11 of FIG. 8.

FIG. 12 is an enlarged, fragmentary sectional view taken along line 12-12 of FIG. 8.

FIG. 13 is an enlarged, fragmentary elevational view, broken away in parts to show structure, showing a cable connection at the lower left hand corner of the frame of FIG. 7 when the latter is in starting position.

FIG. 14 is an enlarged fragmentary elevational view showing a cable connection at the lower right hand corner of the frame of FIG. 7 when the latter is in starting position.

FIG. 15 is an enlarged fragmentary top plan view of the cable connection of FIG. 13.

FIG. 16 is an enlarged cross sectional view, broken in width, taken along line 1616 of FIG. 7.

FIG. 17 is an enlarged fragmentary cross sectional view taken along line 17--17 of FIG. 7.

FIG. 18 is a fragmentary sectional view taken of line 1818-of FIG. 17.

FIG. 19 is a schematic view illustrating the cable holddown relation between the frame and its support at the first step in the method.

FIG. 20 is a view similar to that of FIG. 19 but with the frame at the final step.

FIG. 21 is a reduced size top plan view illustrating a pair of tubes secured together in the formation of a tube passageway in which a pair of the tubes formed by the method are secured together and dot-dash lines indicate the position of a third tube to be positioned in alignment with the others.

FIG. 22 is an enlarged fragmentary cross sectional view taken along lines 2222 of FIG. 21.

FIG. 23 is a cross sectional view generally illustrative of a finally completed tube section including concrete therein and a pair of vehicular passageways. A general understanding of the invention may be had by reference to FIGS. 1, 19, 20.

The cross sectional outline or shape of the frame to which the outer shell is to be secured is seen in FIG. 1, which frame comprises a horizontal, bottom frame portion generally designated 1, a generally vertically disposed side frame portion 2, a horizontal top frame portion 3 and a side frame portion 4 in opposed relation to side frame portion 2.

Each of the frame portions 14 is formed by a horizontally extending row of corresponding elongated frame members, such as T beam members that are in each row in spaced, side by side, parallel relation. The spacing of the beam member-s in each of the rows may vary, and the corresponding beam members in each row are in parallel, vertical planes.

The beam members of the bottom frame portion 1 are each designated (FIG. 7), those of side frame portion 2 are numbered 6, those of the top frame portion are designated 7, while those of the side frame portion 4 are designated 8.

One of the corresponding ends of the beam members 5 of portion 1 are welded to the lower ends of the beam members 6 of portion 2 at 9 (FIG. 7) and opposite upper ends of beam members 6 of side portion 2 are welded to one of the corresponding ends of the beam members 7 of the upper portion 3 at 10. The other ends of beam members 7 are welded at 11 to the upper ends of the beam members 8 of side frame portion 4. The lower ends of the beam members 8 are welded at 12 to the ends of lower beam members 5 that are opposite to the junctures 9 between beam members 5 and 6.

The cross heads on the T beams referably are innermost relative to the frame that is formed, and which frame may be generally designated 15.

The T-members 5-8 of each row may be secured in spaced relation by longitudinal stringers 16 (FIG. 8) or any other suitable means. The word longitudinal as herein used is with reference to the direction of the bore of the tube to be formed. The opening within the outline defined by the bottom, top and side frame members (FIGS. 1, 7) may be considered the bore. Thus the length of the frame or tube will be the direction of stringers 16.

If the outer shell is thin enough for bending as it is applied, two planar strips or sections are laid end to end on horizontally elongated base 17 ('FIG. 1) one strip extending from juncture 12 to 9 for the bottom of the frame, and the other at least equal to the length of the remaining outer perimeter of frame 1.

The length of the tube fra'me relates to the dimension from one open end to the other in a direction at a right angle to the ribs or beams of the tube frame.

The bottom of frame 15 is positioned on the bottom section of the metal strip that, in turn, is supported on the left end of base 17 as is diagrammatically indicated in full line at the left end of FIG. 1. The free edges of the T members of bottom frame portion 1 will be supported on the upper surface of the metal strip, and the lower left hand corner of the frame 15, as seen in FIG. 1 may be even with the lower end of the side frame 4. When the frame is so positioned, the T members and lower stringers 16 (such stringers being in pairs at the top and bottom of the frame) are welded to the bottom section.

Side frame portion 2 of frame 15 faces toward the side of the remaining section of the strip; and after the T-mem- 'bers 5 of the frame bottom have been welded to the bottom section of the strip, the frame is rotated to dot-dash line position A (FIG. 1) when the adjoining ends of the strip are welded together. Then the movement of the frame continues through positions 1820 to position 21, being progressively welded to the cover plate as it moves, after which the opposite ends of the two sections of the strip are welded together at junction 12, the one section being bent to conform to the outline of the frame during said movement.

Normally the metal cover plate is slightly larger than the outside perimeter of the frame 15, so as to insure the final end edge of the strip substantially abutting and fitting against the initial edge along the end of the strip that was initially welded to the frame. Such a fit may readily be accomplished by cutting off the slight surplus metal at the final end of the metal strip when the frame substantially reaches position 21. It is to be understood that the total length of the metal cover may be approximately feet, and the thickness of the metal may be substantially Vs inches.

By the above method, the metal strip is formed to the frame as the frame is rotated along its path from left to right.

The rotation of the tube frame is efiected by supporting and driving it at its central longitudinal axis for said rotation as will later be described in detail and since the frame is irregular in cross sectional contour, the position of the central axis will vary vertically to correspond to the variations in the vertical distance between the axis and the planar surface of the cover plate as the frame moves from one end of the base 17 to the other.

The frame 15 must be held down against the cover plate during the rotation of the frame from one end of the base 17 to the other end, and means is provided for accomplishing this result, as will be explained in detail later on.

Where the metal for the cover shell on the frame is too thick to permit forming it onto the frame from planar strips as the frame is moved from one end of base 17 to the other, the outer shell may be preformed to provide a bottom plate 24 (FIG. 2), and end plate 25, and a combined top and end plate 26. Substantially the same method and apparatus is employed in such a case, as where the cover strips were planar. For example, while it may be impossible to bend a strip of one-half inch thickness as the tube frame is moved from one end of the base 17 to the other, it may be possible to do so where the strip is of an inch in thickness.

In securing plates 24 and 25 to the frame 15, the plate 24 is positioned on one end of the bed or base 17, in the position shown in FIG. 1 in full line at the left end of the base, but it is supported on plate 24 so that the point 12 of the frame will be at the left hand edge of the plate 24.

The two plates 24, 25 adjoin each other at point 27, which is the point where plate 25 will extend over the lower straight part of portion 2 of frame 15.

The frame 15, being positioned on the bottom plate 24 so that point 12 is approximately even with the free end edge of said plate (which is to the left as seen in FIG. 1), the right hand end of the planar bottom portion 1 of the tube frame will be at the juncture 27 between the plate 24 and plate 25.

The ribs or beams 5 are then welded to the bottom plate 24, and the frame is then rolled to the right to dot-dash line position 28 (FIG. 2) and the ribs of the flat, uncurved portion 29 (FIG. 1) of frame side 2 are Welded to the similarly uncurved portion of plate 25. When the frame is in its position 28 shown in FIG. 2, the curved portion of said frame side 2 will be substantially against, and follow, the curved portion of the plate 25. The plates 24, 25 are welded together along their juncture at 27 when the frame is in dot-dash line position 28, and when the frame is in said latter position, the ribs 6 of side frame portion 2 are welded to the section 29 and thereafter the frame is rolled to and through position 18 and the welding of the curved portions of ribs 6 to the curved portion of plate 25 progressively con tinues until the frame is in dot-dash line position 19.

Any suitable supporting means 34 (FIGS. 2, 3) may be employed for supporting the plate 25 in the upwardly extending position of the curved portion thereof until the flat portion of section 29 is welded to ribs 6. This support means may comprise one or more hydraulically extensible braces pivotally connected at 35 to the base 17 for upward swinging to the desired angle relative to horizontal, and a releasable prop 36 may support the brace in the desired angle. After the portion 29 of the plate 25 is welded to ribs 6, the prop may be released or the brace collapsed, or both, so that the plate 25 may roll with the frame 15 to and through the position 18 (FIG. 1) with the progressive welding of the plate to said ribs continuing as the frame so rolls, until the terminating end of the curved portion of plate 25 is in a position to substantially abut the edge 37 of the top plate 26, when the adjoining edges of plates 25 and 26 will be welded together. Supports 38, operating in the same manner as supports 34, support the curved section 39 on top plate 26.

The frame 15 will be substantially upside down in position 19 when the aforesaid adjoining edges of plates 25, 26 are welded together, and the flat portion of plate 26 that is to form the top of the tube is then welded to the beams or ribs 7 of the top 3 of the frame 15.

A continuation of the rotation of frame 15 to and through position 20, and progressive welding of the side wall section 39 of plate 26 will result in the frame reaching position 21 in which it is fully secured to the frame by welding. The end edge 40 of section 39 will, of course, be Welded to the free edge of bottom plate 24 When the frame is substantially in position 21. As already stated, the plate 26 may be slightly longer than normal to enable a substantially perfect joining of the adjacent edges of section 39 with plate 5 should there be any slight variation. Any surplus is cut off to make an accurate fit.

Positioning lugs 43 (FIGS. 2, 3) are secured to the outer side of the plates 24, 25, 26 for abutting cross members 44 of base 17 in order to properly position the plates relative to each other for securement to the frame 15. The lug and cross member for positioning plate 24 are not shown, but the lug positions plate 24 so that its right .hand end edge (FIG. 2) will adjoin the edge of plate 25. Each of the cross members or beams 44 is welded at its ends to the longitudinally extending side members 45 of base 17, and said cross members are positioned wherever any transverse welding of the cover plate or plates occurs (FIG. 2) so as to support the plates against the cross members at such points.

As an example of the tube frame 15 as a whole, there may be six complete frame sections, each section formed by a set of beam members 5-8, where the tube section to be formed is thirty-six feet in length, these members may be spaced approximately six feet apart with the end members spaced approximately three feet from the ends of each tube section (FIG. 8). The opposite end frame members of the row of six frame members are each generally designated 46.

A pair of vertical, horizontally spaced posts 47 extend between and are suitably secured at their upper and lower ends to the stringers 16 at the junctures between the tube frame members adjacent to the end members 46 and said stringers (FIGS. 11, 12). These posts are equally spaced at opposite sides of a vertical plane bisecting frame 15 lengthwise. If desired or required, any number of such posts may be secured to the stringers 16.

The base 17 further includes longitudinally extending I beams 48, parallel with and spaced apart between the side frame I beams 45 (FIG. 4) so they will be positioned below each of the rib sections of the tube frame 15.

During the welding of the outer shell or cover onto the tube frame, clips 49 may be Welded to the inner sides of the tube shell adjacent to the ends of the tube (FIG. 9), said clips being secured to the inner side of the shell or cover at spaced intervals. Each clip 49 has a projection 50 directed generally axially of the tube and spaced from the latter for extending over the generally radially inwardly facing surface of the outer flange 53 of channel members 54, one of such channel members being at each end of the tube frame.

Said channel members 54 follow the cross sectional contour of the tube or tube frame, and the open sides of the channel members 54 are directed toward each other so that the flange 55 forming the side of the channel opposite to side 53 defines the inner periphery of each channel member while the bottom walls 56 of the two channel members are vertical and face outwardly at opposite ends of the tube frames and are substantially flush with the end edges of the outside tube cover or shell that is applied to the tube frame.

The channel members 54 are part of an auxiliary frame, which may be called a jig frame to distinguish it from the tube frame.

The jig frame is removable from the tube frame, and it includes jig stringers 57 (FIGS. 7, 9) that are parallel with the permanent stringers 16. Said jig stringers are each preferably positioned at substantially one of the corners of the tube frame 15, and others corresponding thereto in structure may be used if desired according to the size and contour of the tube frame.

Jig stringers 57 may be channel members and one of the flanges 58 thereof (FIG. 9) is bolted by bolts 59 to the inner flange 55 of each of the end channel members 54.

Welded to each jig stringer 57 adjacent to their ends are clips 63 (FIG. 17) projecting therefrom, and each clip includes a laterally extending projection 64 that extends over one of the flanges 65 of the members 46. A second clip 66 is adjacent to each clip 63 at the opposite side of the tube frame members engaged by clip 63, and each clip 66 is formed with a projection 67 that corresponds to projection 64, and which projection 67 is adapted to extend over the other flange -68 of each tubeframe member 46.

A plate 69 is welded to each jig stringer and a screw 70 threadedly extends through each plate 69 and is rotatably connected at its outer end with a slide member 71 that is slidably supported between the flanges of each jig stringer 57 and each clip 66 is Welded to each side member 71. Projections 74 on each slide member extend through slots 75 (FIG. 18) in the flanges of each jig stringer to hold and guide the slide members. Upon rotating each screw 70 in one direction each clip 66 will move toward stationary clip 63 opposite thereto for tight ly clamping the jig stringers to the tube frame sections;

and upon turning the screws in an opposite direction, the jig stringers will be released so that they may be removed when bolts 59 (FIG. 9) are removed, and the removal of bolts 59 will enable removal of channels 54.

The rods 76 (FIG. 7) are releasably secured at one of their ends to each of the jig stringers in any suitable manner, such as by conventional interengaged eye connections (FIG. 17); and they may be similarly secured at their opposite ends to stringers 16. Each tie rod may include a turn-buckle 77 or other tightening means for tightening the rods to brace the tube frame 15. These tie rods may obviously vary in number and be arranged according to the design and contour of the tube frame or as may be found necessary to adequately brace the tube frame.

Of corresponding linear contour to each end channel member 54 (FIG. 9) is an outer channel member generally designated 78. Each outer channel member or outside channel member 78 is provided with brackets 79 that are rigid therewith for bolting the outer channel member 78 and each end channel member 54 by bolts 80.

Brackets 79 and bolts 80 secure each outer channel member 78 in a position against the bottom wall 56 of each end channel member 54, with the open side of each outer channel member opening generally radially outwardly of the axis of the tube frame 15. The flange 82 of each outer channel member 78 is against the outwardly facing surface of the bottom wall 56 of each end channel member 54, and said flange projects radially outwardly of the flange 53 on each channel member 54 so that the cover shell for the tube will be between the radially outwardly projecting portions of the outer channel members 78. Also, as the cover shell is applied, the said outwardly projecting portions of the outer channel members 78 will function to guide the plate or plates of the shell between said projecting portions.

A pair of upper and lower vertically disposed, horizontally extending plates 83 are bolted by bolts 86 (FIG. 7) to the bottom 56 of each of the end jig members 54 in positions midway between the opposite sides 2, 4 of the tube frame and to the upper and lower sections of the members 54 that are at the upper and lower sides of the tube frame.

Rigidly secured to and extending between each pair of upper and lower plates are a pair of vertical, horizontally extending posts 87.

Intermediate each pair of plates 83 is a central, horizontally extending plate 88.

Coaxial shafts 90 (FIG. 16) are rotatably supported on bearings 89, each shaft projecting outwardly of each pair of plates 88 relative to the inside of the tube frames, and corresponding spur gears 93 are respectively secured on the outwardly projecting ends of said shafts 90. The gears of corresponding conventional gear reducers respectively in housings 94 are connected with the inner ends of shafts 90 and with the ends of a motor driven shaft 95 that is between said reducers. An electric motor and brake 96 is connected with shaft 95 that extends to the gear reducer for driving the pinion gears 93 in one direction or the other. Couplings 92. releasably connect the shaft situated at its ends. The reducers and motor may be secured to the plate 88 that is adjacent thereto by any suitable means.

As seen in FIG. 4, the upper surfaces of the I beams 45, 48 and of the cross members 44 are coplanar and form the surfaces on which the tube frame and cover shell are supported with the shell between the tube frame and said surfaces, and lugs 97 may be welded to the marginal portions of the shell adjacent each inner upper flange of the I beams 45 to insure positioning of the shell. Only one side portion of the base is shown in FIG. 4, the opposite being the same.

Along each side of the base is a horizonally extending vertically disposed plate 98 welded to each I beam 45,

each of which plates have an upstanding upper marginal portion 99 projecting above the upper surface of each of said I beams.

Said marginal portions are spaced outwardly of the end edges of the outer shell, which shell may be generally designated 100, so that the outer channel members 78 will be disposed between the end edges of the shell, and said marginal portions 99 also assist in guiding frame 15 and the jig frame as the latter is moved along the bed 17 from one end thereof to the other.

In order to insure that the tube frame will be held down against the shell 100 to thereby also hold the shell against the base 17 during welding of the shell to the frame 15 and during movement of the frame over the base, I provide two corresponding pairs of wire ropes.

FIGS. 19, 20 illustrate diagrammatically these ropes and their manner of operation.

Referring to FIGS. 19, 20 the line 15 indicates the tube frame, the latter being in a position at the left end of base 17 in a starting position.

The cables 103 of one pair are rigidly secured at one of their ends to the left end of base 17 at 104-, and they extend within the channel members 78 (FIG. 9) completely around the said members to point 105 where they are each secured to the tube frame by any suitable means, such as bolt-eye connection 106 (FIG. 15).

The cables of the outer pair are each designated 10-7 and are rigidly secured at one of their ends to the opposite end of bases 17 and 108, while the opposite ends of the cables 107 are secured to the tube frame 15 at 109 by a means corresponding to the bolt-eye connection 106.

As the frame 15 is moved on bed 17 from the position shown in FIG. 19 to the position shown in FIG. 20, the cables 103 will unwind on the frame within the outer channel members 78 while cables 107 will wind on said outer channel members, but within the latter, thereby holding the tube frame down against the tube shell during welding along whichever portion of the shell is below the frame, and guiding said frame in its path.

A row of upright standards 110 along each side of bed 17 extending longitudinally of the latter supports a rack 113 having its teeth directed generally upwardly for engagement with the teeth of the pinions 93. These racks are identical and the roWs of teeth thereon follow the same contour.

Substantially continuous tracks 116 having guide flanges 111 therealong extend parallel with racks 113 for the length of base 17 and rollers on the outer ends of shafts 90 are adapted to roll on and be guided by said racks to support the weight of frame 15 during movement of the latter except as hereafter described. In positions 19, 20, hold-down tracks 114 above and parallel with tracks 116 may be engaged by rollers 115 to hold the frame down independently of other means until the overbalanced weight of frame 15 at opposite sides of said positions, with cables 103, 107, holds the tube frame against the sheeting being welded thereto. Track 114 may continue for the length of the base, if desired.

When the frame 19 is in the initial position and positions 19, 20, substantially the entire weight of the tube frame and the jig frame is supported on the portion of the initial sheeting that is to form the cover, rather than any of the weight being on the pinions, rack and rollers, to entirely flatten the sheeting to insure a contact between the frame sections and the sheeting, since it is normal that some irregularities exist in a sheet having the dimensions required for covering the tube frame.

Also the teeth on the rack or pinion, or both, may be modified to insure release of the pinion teeth from the rack through the movement past the juncture between the arcuate sections of the rack as seen in FIG. 10. Such modification is conventional in similar circumstances by shortening the teeth of the pinion or rack. It has been noted that the pinion preferably does not take any of the 9 weight of the frame in the position shown in FIG. 10 or elsewhere.

From the foregoing description it is seen that the permanent tube frame comprises the tube sections 8 and the other corresponding sections and stringers 16. The jig runners 57, the rods 76, channel members 54, outer channel members 78, posts 47, plates 83, may be called the jig frame. The pinions 93, wheel 115, shafts 90, bearings 89, and motor 96, and gear reducers 94 make up the jig that is removable from the tube frame.

In operation, assuming a continuous plate, or sections 24, 25, 26 are on the base 17, the tube frame including the jig frame and all of the parts of the latter are positioned on the cover plate in full line position shown in FIG. 1. The cables 103, 107 are connected With the base 17 and the jig frame as described, and the motor 96 is actuated to move the jig frame on the cover plate or sections thereof through positions 18, 19, 20 and to position 21. The welding of the cover or outer shell progressively continues until the shell fully encloses the tube frame in position 21.

At position 21 the cables 103, 107 are disconnected from the jig frame and therefore the posts 87 and plates 83, 88 including the motor 96 and gear reducers 94 including housings 94 are removed. The shaft coupling or couplings 92 are uncoupled to permit such removal. Also jig stringers 57 and outer channel members 79 are removed. Only the channel members 54 remain on the tube frame. Clips 49 are also removed from the shell.

The tube section may then be bolted to the previously completed tube section by means of bolt 80, and the two sections are welded together along their juncture as seen in FIG. 22 at 116. Thereafter, outer channel members are unbolted from each other and may be removed.

When a desired number of tube sections are joined together, they may be filled with concrete 117 (FIG. 23) leaving the desired passageways 118, 119 to provide for vehicles and utilities. The ends may then be closed and the several sections floated to their sites and sunk to connect with previous sections. These final steps are conventional, and do not form part of the present invention, being merely explanatory of the use of the particular tube sections made by the present invention.

Both a continuous metal sheet to be progressively welded to the outer surface of the tube frame, as described, or sections of metal sheets, pre-formed to be secured to said outer surface of the tube frame may be called metal sheeting; and Where the continuous unitary strip is secured to the frame, it is progressively bent to follow the curved contour of the outer surface of the tube frame immediately ahead of the welding operator. The motor that drives the tube frame may be intermittently actuated, if desired, where, for example, the sheeting is welded to the flat portions of the frame, such as the top and bottom portions, so that the welding of the sheeting to such portions is accomplished before the bending of the sheeting; but when the bending occurs, the welding continues as the sheeting engages the frame.

If desired, the welding steps may initially be by spot welding, and after such welding, the frame may be rotated back and the complete welding accomplished by automatic welding machines. Hence the Words progressively welding may be spot welding at spaced points or continuous welding.

From the foregoing, it is believed that the operation, construction, and analysis of my invention may be readily understood by those skilled in the art without further description; it being borne in mind that numerous changes may be made in details disclosed without departing from the spirit of the invention, as expressed in the claims.

I claim:

1. The method of securing a metal sheeting around a tube-frame having an outer surface of irregular cross sectional contour to which said sheeting is to be secured, comprising the steps of:

(a) supporting said sheeting on a planar horizontally extending support;

(b) supporting said frame over said sheeting with said outer surface in engagement therewith for rotation of said frame over said sheeting in one direction in a horizontally extending path of travel that is parallel with said planar support;

(a) moving said frame in said path by application of a rotary force thereto from a point fixed relative to said frame and movable in an undulatory path disposed in a vertical plane parallel with said path of travel of said frame, the variations of which undulatory path, relative to vertical, correspond at all times during said movement of said frame to the vertical distance between said point and said planar support;

(d) holding said frame against said sheeting during said movement of said frame; and

(e) progressively Welding said sheeting to said frame at the lower side of said frame during said movement of said frame in said one direction.

2. The method as defined in claim 1, in which:

(f) said point is the central axis of said tube frame about which said irregular contour of said outer surface of said tube frame has been developed; and

(g) said progressive welding being from within said tube frame and downwardly.

3. The method as defined in claim 1, including the step of:

(f) progressively bending said sheeting into said engagement thereof with said outer surface of said tube frame during said movement of said tube frame in said path of travel immediately ahead of said welding step whereby said sheeting will progressively conform to said irregular contour of the outer surface of said tube frame.

4. The method of securing a metal sheeting around a tube-frame having an outer surface of irregular cross sectional contour to which said sheeting is to be secured, comprising the steps of:

(a) supporting said sheeting on a planar horizontally extending support;

(b) supporting said frame over said sheeting with said outer surface in engagement therewith for rotation of said frame over said sheeting in one direction in a horizontally extending path of travel that is parallel with said planar support;

(0) moving said frame in said path by application of a rotary force thereto;

((1) holding said frame substantially against said sheeting during said movement of said frame by a force independently of gravity;

(e) welding said sheeting to said frame at the lower side of said frame during said movement of said frame in said one direction.

5. In the method as defined in claim 4:

(f) supporting the major portion of the weight of the frame at points spaced above said sheeting during said movement of said frame.

6. Apparatus for use in securing metal sheeting to the outer sides of a tube frame to form an open ended tube of irregular cross sectional contour corresponding to the desired irregular cross sectional contour of said tube:

(a) a horizontally elongated base adapted to support thereon metal sheeting to be secured to said outer sides of said tube frame for rotating of said tube frame in one direction on said sheeting in a horizontal path of travel extending longitudinally of said base when said sheeting is supported on the latter;

(b) means connected with said tube frame for so rotating the latter in said path;

(c) guide means for guiding said tube frame in said path during said rotating of said tube frame.

7. In apparatus as defined in claim 6:

(d) said guide means including means for holding said frame against said sheeting independently of the influence of gravity on said frame.

8. In apparatus as defined in claim 6:

(d) means for supporting said frame spaced above said base a distance substantially equal to the thickness of the sheeting to be supported on said base, during movement of said frame in said path.

9. Apparatus for use in securing metal sheeting to the outer sides of a tube frame to form an open ended tube of irregular cross sectional contour, and which tube frame has an irregular cross sectional contour corresponding to the desired irregular cross sectional contour of said tube:

(a) a horizontally extending elongated base adapted to support thereon metal sheeting to be secured to said outer sides of said tube frame and further adapted to support said tube frame on said sheeting for rotating of said tube in one direction on said sheeting in a horizontally extending path of travel extending longitudinally of said base when said sheeting is so supported on said base;

(b) means rigid with said base extending generally longitudinally thereof and a power actuated driver on said frame in driving relation with said last mentioned means for positively rotating said frame in said path upon actuation of said driver; and

(0) means on said frame for supporting the latter on its side over said base for movement of its outer sides of irregular cross sectional contour over and in engagement with said sheeting upon said rotation of said frame over said base in said path of travel.

10. In apparatus as defined in claim 9:

(d) hold-down means secured to said base and connected with said frame for holding said sides of said frame against said sheeting during said rotation of said frame under the influence of said driver.

11. In apparatus as defined in claim 9:

(d) said means that is rigid with said base comprising a rack disposed in a vertical plane and extending longitudinally of said base, and said driver including a pinion rotatably carried by said frame in a fixed position thereon with its teeth in mesh with the teeth on said rack;

(e) said rack having a linear contour longitudinally of said path of travel corresponding to the path of travel of said pinion during rotation of said frame on said sheeting and base from one end of the latter to the other.

12. In apparatus as defined in claim 10:

(c) said hold-down means comprising a pair of cables respectively connected at one of their ends to opposite ends of said base and at their opposite ends to said frame at spaced points therearound for simultaneously winding and unwinding around said frame during said rotation of said frame in said path.

13. Apparatus for use in securing metal sheeting to the outer sides of a tube frame to form an open ended tube of irregular cross sectional contour, and which tube frame has an irregular cross sectional contour corresponding to the desired irregular cross sectional contour of said tube:

(a) a horizontally extending elongated base adapted to support metal sheeting thereon to be secured to said outer sides of said tube frame to form said tube, and said base being further adapted to support said tube frame on said sheeting for rotating in one direction on said sheeting in a horizontally extending path of travel extending longitudinally of said base when said sheeting is so supported on said base;

(b) said frame comprising a row of horizontally extending corresponding continuous ribs spaced apart and in alignment longitudinally of said row, the outermost surfaces of said ribs each being of said irregular cross sectional contour and against which surfaces said sheeting is to be secured;

(c) stringers extending longitudinally of said row of ribs connecting them and securing them in said spaced relation;

(d) said row of ribs having a horizontally disposed axis extending transversely of said path about which said irregular cross sectional contour of said outermost surfaces has been developed, and a pair of coaxial pinions on said axis disposed outwardly of opposite ends of said row of ribs and means supported by said ribs supporting said pinions for rotation;

(e) a pair of parallel racks rigid with said base extending longitudinally of the latter having corresponding rows of generally upwardly directed teeth thereon, said last mentioned rows extending along opposite ends of said rows of ribs with the teeth of said pinions in mesh therewith;

(f) said rows of teeth extending along undulatory lines in parallel vertical planes longitudinally of said base, the variations in said undulatory lines relative to vertical corresponding to the vertical distances between said pinions and said sheeting at points along said path of travel during rotation of said frame on said sheeting; and,

(g) power means connected with said pinions for rotating them in one direction for moving said frame in said path of travel.

References Cited UNITED STATES PATENTS 2,061,287 11/1936 Muehl 228-4 2,142,109 1/1939 Burke 29-430 2,342,179 2/1944 Ciesa et a1. 2920O 2,679,278 5/1954 Clark 29200 5 THOMAS H. EAGER, Primary Examiner.

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