US3225432A

US3225432A - Sheet metal assembly tool and method

Info

Publication number: US3225432A
Application number: US255368A
Authority: US
Inventors: Erwin R Widman
Original assignee: Individual
Current assignee: Individual
Priority date: 1963-01-31
Filing date: 1963-01-31
Publication date: 1965-12-28
Anticipated expiration: 1982-12-28

Description

Dec. 28, 1965 WIDMAN 3,225,432

SHEET METAL ASSEMBLY TOOL AND METHOD Filed Jan. 51, 1963 INVENTOR ERW/N A. MDMAW United States Patent 3,225,432 SHEET METAL ASSEMBLY TOOL AND NETHOD Erwin R. Widman, 8615 Elmhurst Ave., Elmhurst, N.Y. Filed Jan. 31, 1963, Ser. No. 255,368 Claims. (Cl. 29-429) This invention relates to sheet metal fabrication techniques and, more particularly, to a novel tool and method for facilitating the assembly of sheet metal parts. While it may have other uses, the invention Was made while attempting to overcome a familiar problem as arises whenever sheet metal duct lengths of rectangular cross-section must be assembled, and therefore the invention will be described in connection with such use.

In fabricating rectangular sheet metal duct lengths, it is common to assemble four sheet metal strips into the desired rectangular shape and to joint the same by any of the common types of folded seams along their conjoining longitudinal edges. Each of those two strips which form the top and bottom walls of the duct is known as a cheek, and each of those strips which form the sidewalls of the duct is known as a wrapper.

In one usual type of duct seam construction, each cheek has a simple turned down flange along each of its longitudinal edges and each wrapper is folded along each of its longitudinal edges in manner so as to form a pocket for receiving the respective of the cheek flanges. The edge folds of the wrapper are such as to provide an upwardly protruding edge which is hammered or otherwise turned down on the cheek after the flange of the latter has been received in the referred to wrapper pocket. The seam thus formed is more commonly called a Pittsburg type seam, and the invention will be described in connection with the assembly of ducts having Pittsburg seams, although it will be understood that the invention is useful in assembling ducts having other types of seams.

For air conditioning duct Work and the like, it is common to assemble the duct in sections, sometimes of substantial length. Moreover, the duct sections may be quite high and quite Wide when finally assembled, and it is seen that considerable difliculty is often encountered when attempting to assemble four sheets or strips of sheet metal into a duct section by reason of the tendency of the sheets to bend slightly under their own Weight and to otherwise misalign while positioning the same for joining. Even when assembling relatively short duct sections, or those which do not have particular great height or width, and even where a special fixture is provided, the work of two men has been required heretofore in duct assembly operations.

By the present invention, however, it is found that in most cases only one man is required to fully assemble and complete the fabrication of the duct, and that no special fixtures or other holding devices, other than one or sometimes more of the tools of the invention, are required in the work. In addition, it is found that the total time spent by one man in assembling a duct section in accordance with the present invention is usually less than the time spent by each of two men using previously known methods and equipment.

The invention is primarily intended for commercial use where such savings in both the number of men and the time required to assemble duct sections or length will in the aggregate substantially reduce the cost of sheet metal fabrication operations. The tool as is provided by the invention is relatively uncomplex and, therefore, economical to make, yet its use in accordance with the method to be described will contribute to the savings as are elfected through use of the method. In this connec- 3,225,432 Patented Dec. 28, 1965 tion, the tool is intended to accommodate duct cheeks and wrappers of the same or differing widths, as well as those used to fabricate a wide variety of duct sizes. However, the tool may be modified, as will be described, for use in mass production fabrication operations wherein numerous sections of only one sized duct are to be made.

Briefly describing the present invention, a tool is provided for holding the predetermined spacing between the wrappers or side walls of the duct while one of the checks is fitted thereon. The tool may be considered as having a check guide surface and a wrapper guide surface, each of which has a plurality of notches therein. Considering the notches in appropriate pairs, the cheek guide surface notches and the wrapper guide surface notches respectively receive, for example, both longitudinal side edges of the cheek and the respective conjoining longitudinal side edges of each of the wrappers during the assembly thereof. The method involves standing both of the Wrappers on edge and placing the wrapper guide notches of the tool in engagement with the respective upstanding edges of the wrappers at generally a middle length location therealong and so as to bridge and hold a predetermined spacing therebetween. Thereupon, starting at one end of the pair of wrappers, the cheek is progressively fitted into proper conjoining relationship with the wrappers. At the starting end, the longitudinally extending downwardly turned flanges at one end of the cheek are positioned within the respective pockets which have been previously formed along the wrapper edges, while the cheek flanges at the location of the tool engage and will be guided by the pair of cheek guide notches of the tool. As the length of the cheek is progressively assembled into the wrapper pockets the tool is moved progressively along the wrapper edges, the wrapper guide notches at the underside of the tool sliding on the upstanding wrapper edges and the downwardly turned cheek flanges being in sliding engagement with the pair of notches at the cheek guide surface at the upperside of the tool. Where the length of duct to be assembled is more than about four feet, it has been found convenient to use two such tools in practicing the method, one tool being so placed in engagement with the wrappers and cheek flanges somewhat near the referred to starting end of the duct and the second tool being so placed adjacent the finishing end of the duct. Further, it may be found advantageous in some instances to also position one or two of the tools underneath the lower edges of the upstanding wrappers to hold the predetermined spacing thereat. In such instances, the lower edges of the Wrappers may be placed respectively in appropriately spaced notches of the cheek guide surface of the tool.

These and other objects, features and advantages of the invention will become more fully apparent from the following detailed description thereof, when taken with reference to the accompanying drawings in which:

FIGURE 1 is an enlarged perspective view of the tool provided by the invention in a preferred form thereof;

FIGURE 2 is a somewhat further enlarged fragmentary perspective view of the tool provided by the invention in a modified form thereof;

FIGURE 3 is a view similar to FIGURE 1, but on a smaller scale, illustrating still another modified form of the invention;

FIGURE 4 is a fragmentary view in cross-section of a partially fabricated duct section, and showing the tool of FIGURE 1 in position for completing the assembly of the duct in accordance with the method of the invention;

FIGURE 5 is a side view of the duct of FIGURE 4 during assembly in accordance with the method of the invention, the view being shown on a somewhat smaller scale;

FIGURE 6 is a top plan view of the FIGURE showing; and

FIGURE 7 is a side view, to a smaller scale, of what may be considered an extremely long duct section as the same appears when being assembled accordingto a modified method provided by the invention.

Referring first to FIGURE 1 of the drawings, there is shown a preferred form of the duct assembly tool of the invention, the tool being adapted as will be described for assembling duct sections of a variety of widths. The tool, generally indicated by reference numeral 10, has an elongated body 11 which, in cross-section, has an inverted V-shaped portion 12 and a pair of integrally formed, parallel

vertical portions

13 and 14. The

vertical portions

13 and 14 respectively depend from the legs 12a and 12b of the V-shaped portion 12, and together provide a pair of

underside surfaces

15 and 16 of the tool. Since in accordance with the inventive method to be described these

surfaces

15 and 16 will guide and thereby retain the spacing between a pair of duct wrappers during assembly of a cheek thereto, they may also be referred to as

wrapper guide surfaces

15 and 16. Further, it will be noted that either of the integrated leg and

vertical portions

12a, 13 or 1212, 14 may be considered as a means for supporting the body 11 of the horizontally disposed tool in an upright position during its use as will be described.

A linear upperside surface of the tool is generated by the apex of the inverted V-shaped body portion 12. This surface is indicated by reference numeral 17, and it will later be understood that the surface 17 is uppermost during tool use and may also be referred to as the cheek guide surface of the tool.

The body 11 of the tool embodiments to be described is conveniently made by bending a strip or sheet of sixteen gauge sheet metal to the desired shape. Moreover, and so that the tool is useful for assembling most conventional sizes of duct, it has been found that a suitable length for the elongated body 11 is twenty-five inches (25").

The FIGURE 1 embodiment of. the tool includes a plurality of spaced apart, channel-shaped notches 18 on each of the underside or wrapper guide surfaces and 16. Each of the notches 18 has a rounded bottom portion 18a to facilitate its sliding in contact engagement with an edge of one of the wrappers, as will be described, and the sidewalls of each notch (not numbered) are preferably tapered outwardly towards the open end of the notch. Moreover, each of the notches 18 of either of the

surfaces

15 or 16 is aligned, in transverse direction with respect to the body 11, with a notch 18 of the other of said surfaces. The spacing apart of the notches 18 along the length of either of the

surfaces

15 or 16 is the same, and is such that pairs of notches on each surface, considering each notch of the pair as being inward of the respectively opposite ends of the surface, are spaced apart a distance which is substantially equal to the width between wrappers of a conventional sized duct section. Since duct widths are usually varied in one inch increments, it has been found that one inch spacing between each successive notch 18 is satisfactory.

The upperside, or cheek guide surface 17 also has a plurality of spaced apart, channel-shaped notches 19 formed thereon. These notches 19 are preferably formed bydrill holes through the body 11 along the linear surface 17, and it will be noted that such drilling provides a rounded bottom 19a of each notch 19, as is desirable. It has also been found that each of the notches 19 may be spaced commensurately with the spacing of the notches 18 along either of the underside, or

wrapper guide surfaces

15, 16 so that any notch 19 is in transverse alignment with a pair of the aforesaid transversely aligned notches 18.

A modified tool 20 having a similarly shaped body 11 is illustrated in FIGURE 3, and it will be noted that the body It has an inverted V-shaped portion 12 providing a linear, upperside surface 17, and a pair of parallel

vertical portions

13 and 14 which depend from the legs 12a and 12b of the V-shaped portion 12 and provide the pair of

underside surfaces

15 and 16. In respect of all of these elements, the FIGURE 3 embodiment is identical with that shown in FIGURE 1, and, therefore, these elements are referenced by the same numerals. However, each of the

underside surfaces

15 and 16 has only one pair of spaced apart, channel shaped notches 18, and the linear, upperside surface has only one pair of notches 19, each of the

respective notches

18 and 19 being shaped or formed as previously described and, therefore, referenced by numerals identical with those for the same notch elements in the FIGURE 1 embodiment. Moreover, the corresponding notches of each pair thereof in the respective surfaces are in alignment in transverse direction of the body 11, as previously described.

The length of the body 11 of the tool 20 of FIGURE 3 is selected to generally correspond with the width between wrappers of any one, conventional sized duct section which is to be mass produced, and the respective pairs of notches along its length are spaced apart to conform with the width between wrappers of the duct section. Thus, the tool 20 is adapted for commercial production assembly of duct sections having uniform width between wrappers.

Another modified tool 30 is illustrated in FIGURE 2. In this embodiment, which is somewhat similar to the FIGURE 1 embodiment as regards its adaption for use in assembling a variety of duct sizes, the body 21 of the tool is of inverted V-shape as might be formed by a length of angle iron, but which also may be formed by longitudinally bending a strip of sixteen gauge sheet metal to the desired angle at the apex of the bend. Thus, the inverted V- shaped structure provides a pair of underside surfaces 22 and 23, and an upperside surface 24 of the tool. Spaced apart, channel shaped

notches

18 and 19, as previously described in connection with the FIGURE 1 embodiment, are respectively located along the underside surfaces 22, 23 and the upperside surface 24. Thus, although not preferred, it is seen that the depending parallel vertical portions of the body, as described in connection with the other embodiments, may under some conditions be eliminated.

Regarding all of the described embodiments, it has been found that the vertical distance measured between the rounded bottom portions 18a, 19a of the transversely aligned

notches

18 and 19 should be about one inch in order to avoid undue bending of the duct cheek and to promote ease in the sliding of the tool along the wrapper edges during duct section assembly operations as will be hereinafter described.

The method of the invention will now be described, and for this purpose reference is made to FIGURES 4-7 of the drawings.

Referring first to FIGURE 4, the cross-sectional view of a duct section 39 which is being assembled clearly shows the duct sidewalls 40 (which are more commonly referred to as the wrappers) and the top and bottom walls 42 (more commonly called the cheeks) which are intended to be assembled and joined using a Pittsburgh type joint 44 along each of the four longitudinally extending edges of the duct section. The Pittsburgh joint when fully formed is as shown at the lower left-hand corner of the drawing. To form the joint, it will be understood that each longitudinal edge portion 45 of each wrapper is folded outwardly and downwardly, and then upwardly so as to form a longitudinally extending pocket 46 and protruding edge 48 therealong. Of course, the pocket 46 might be formed at the duct interior, rather than the duct exterior side of the wrapper as is shown. Along each of the longitudinally extending side edges of each cheek there is a downwardly turned flange portion 47 which will be received in the comating wrapper pocket 46, as indicated. When the cheek flanges are within the respective wrapper pockets, the upwardly protruding edge portions 48 of the wrapper edges 45 are turned down over the surface of the cheek to complete the Pittsburgh joint.

Prior to assembling such a duct section, each of its four wall sections are separate and heretofore it has been found difficult to position the wrappers and cheeks with respect to each other for joining. That is, even where the duct section is relatively short and the respective widths of its wall sections are relatively narrow, the handling of the wall sections when attempting to position the downwardly turned cheek flanges within the respective Wrapper pockets is rather cumbersome. Usually the assembly operation requires one man to hold both wrappers in a suitable position while another man progressively fits the cheek flanges within the wrapper pockets. By the method of the present invention, however, only one man is required to perform the duct section assembly and joining operations. I

In accordance with a preferred practice of the inventive method, a relatively short duct section, having length less than about four feet, is conveniently assembled by first standing one of the wrappers 40 upright on one of its longitudinally extending side edges 45 (actually on the protruding edge portion 48), and then placing one of the underside surface notches 18 of the tool in contact engagement with the opposite, upwardly facing protruding edge portions 48, the engaging notch 18 being one which is disposed near one of the ends of the tool 10. By simply holding the tool 10 with one hand, this first wrapper 40 is easily held in this upright position.

Using the other hand, which is free, the assembler then stands the other wrapper upright on one of its longitudinally extending side edges and places the same under the tool 10 in generally parallel, spaced-apart relation with respect to the first wrapper, engaging another notch 18 of the tool 10 with the upwardly facing protruding edge portion 48 of this second wrapper. The second notch 18 is selected to correspond with the desired spacing between wrappers in the finished duct section, as indicated in FIGURE 4.

Where such a short length of duct section is being assembled, it will be found that a single tool 10, when so engaging the pair of wrappers, will adequately retain the wrappers in such upstanding, spaced-apart parallel relation. Where the finally assembled duct section has length of more than about four feet, it will be found more expedient to place another tool 10 in similar contact engagement with both of the upright wrappers at another location along the duct section length as indicated, for example, by the two uppermost tools 10 shown in FIG- URE 7. In any event, it will be found that the bridging of the tool or tools 1% across the two wrappers as has been described will be adequate to maintain the wrappers in such standing position so that the hands are free for the purpose of assembling a cheek to the latter. However, it should be noted that, for convenience in carrying out the subsequent assembly operations, the tool 10 should be located along the length of the wrappers a substantial distance from one end 50 of the duct section being assembled.

FIGURES 4-6, inclusive, illustrate how a cheek 42 is assembled to a pair of wrappers to form a relatively short length duct section 39. The tool It is engagement with the respective upstanding longitudinal side edges of the wrappers maintains the wrappers in proper transversely spaced-apart relation. The cheek 42 is positioned over the upstanding wrappers so that an end 51 thereof is generally in alignment with the ends 54 of each of the wrappers and its downwardly turned flanges 47 placed in engagement with that pair of notches 19, at the upperside edge 17 of the tool, which are substantially in respective alignment with the two notches 18 which are in engagement with the wrappers. The flanges 47 at the referred to end 51 of the cheek 42 are then placed in seated engagement within the respective pockets 46 of the wrap- 6 pers, and it will be found that in this partially assembled condition the two wrappers and the cheek can be conveniently jockeyed into proper end alignment with respect to each other so as to properly arrange the end 50 of the duct section.

Working from the referred to end 50 of the duct section, the flanges 47 of the cheek 42 are then progressively fitted within the respective wrapper pockets 46 along the length of the duct section by simply pushing or pressing on the cheek and progressively moving or sliding the tool 10 along the wrappers in the same direction until the cheek is fully assembled to the wrappers. Of course, by the time this assembly operation has been completed, the tool 10 will have been removed from the work.

The longitudinally extending, upwardly protruding edge 48 of each wrapper is then hammered or otherwise turned down over the cheek 42 to complete the Pittsburgh joints at this side of the duct section, and the thus partially completed duct section is then inverted so that the opposite longitudinal side edges of the wrapper sections face uppermost.

A tool 16 is placed in contact engagement with the protruding edges 48 at the now upwardly facing sides of the wrappers, an appropriate pair of notches 18 of the tool holding the spacing between wrappers at a location therealong which is a substantial distance from the one end 50 of the duct section 39, in manner similar to that as has been previously described. A second cheek 42 is then positioned over the partially completed duct section 39, its downwardly turned flanges 47 being placed in engagement with the appropriate pair of upper-side notches 19 of the tool 10 and with the wrapper pockets 46 at the end 50 of the duct section, also in manner as has been described. The flanges 47 of the second check 42 are then progressively fitted within the wrapper pockets 48 along the entire length of the duct section 39, the tool 10 being progressively moved in the same direction along the wrappers until the assembling is completed. When the protruding edges 48 of the wrappers have been turned down over this section cheek 42 so as to firmly join the latter to the pair of wrappers, the duct section 39 has been completely fabricated.

Referring to FIGURE 7, it will be understood that when assembling a very long duct section 53 the second tool 10, which is more remote from duct section end 50 than is the first tool 10, also serves to support the cheek 42 at a second location therealong to prevent excessive flexure thereof as might otherwise interfere with the assembly operation.

Also referring to FIGURE 7, it should be noted that one, or perhaps two tools 10 might in some instances be initially used to support the underside edge portions 48 of the upstanding Wrappers in proper parallel, spaced-apart relation when a check 42 has not yet been joined thereto. As shown, the underside edge portions 48 will engage an appropriately spaced-apart pair of notches 19 on the upperside or check guide surface 17 of the tool 10, the tool resting on its underside or wrapper guide surfaces 16. Such use of a tool or tools 10 will be found especially convenient in circumstances where the width of the wrappers is quite large.

It will also be understood that the tool 30 of FIGURE 2 and the tool 20 of FIGURE 3 are used in the same manner as has been described when practicig the method of the invention.

Thus, a tool and method for facilitating the assembly of sheet metal parts has been described which achieves all of the objects of the invention.

What is claimed is:

1. A tool for assembling a sheet metal duct section or the like, said tool comprising an elongated body having opposite free ends and including an upperside surface and an underside surface disposed in the direction of elongation of said body, underside surface means for supporting said body in upright position with its said upperside surface uppermost, and a pair of spaced apart and transversely disposed guide means on said underside surface, each of said guide means being substantially channel-shaped and said pair thereof being respectively disposed substantially adjacent said opposite ends of said body.

2. A tool for assembling a sheet metal duct section or the like, said tool comprising an elongated body having opposite free ends and including an upperside surface and an underside surface disposed in the direction of elongation of said body, underside surface means for supporting said body in upright position with its said upperside surface uppermost, a pair of spaced apart and transversely disposed guide means on said underside surface, said guide means being substantially channel-shaped and said pair thereof being respectively disposed substantially adjacent said opposite ends of said body, and a second pair of spaced apart and transversely disposed guide means on said upperside surface, each of said second guide means being substantially channel-shaped and said pair thereof being respectively disposed substantially adjacent said opposite ends of said body.

3. A tool for assembling a sheet metal duct section or the like, said tool comprising an elongated body having a substantially V-shaped cross-section and including an upperside surface provided by the elongated edge of said body which is generated by the apex of said V-shape and a pair of underside surfaces provided by the pair of elongated edges of said body which are generated by the respective free ends of the leg-portions of said V-shape, a plurality of spaced apart and transversely disposed guide means on at least one of said underside surfaces, and a second plurality of spaced apart and transversely disposed guide means on said upperside surface, each of said guide means being substantially channel-shaped.

4. A tool in accordince with claim 3 wherein each of the first said plurality of guide means comprises means defining a notch of that said underside surface on which it is disposed.

5. A tool in accordance with claim 3 wherein each of the first and second said pluralities of guide means comprises means defining a notch of that said body surface on which it is disposed, each said notch having a rounded bottom portion.

6. A tool for assembling a sheet metal duct section or the like, said tool comprising an elongated body having opposite free ends, said body having in cross-section a substantially V-shaped portion and a pair of parallel vertical portions each depending from an integral with one of the legs of said V-shape, said body including an upperside surface provided by the elongated edge of said body which is generated by the apex of said V-shape and a pair of underside surfaces provided by the pair of elongated edges of said body which are generated by the respective free ends of said parallel vertical portions, means defining a plurality of spaced apart and substantially channelshaped notches on each of said underside surfaces, each of said notches having a rounded bottom and being substantially equally spaced apart with respect to each respectively adjacent notch, said plurality of notches of each said underside surface including a pair thereof respectively disposed adjacent said opposite ends of the body, and each notch of one said underside surface being respectively aligned, in transverse direction with respect to said body, with a notch of said other underside surface to form respective pairs of transversely aligned notches of said underside surfaces, and means defining a plurality of spaced apart and substantially channel-shaped notches on said upperside surface, each of said upperside surface notches having a rounded bottom and each respectively being substantially in alignment, in transverse direction with respect to said body, with said transversely aligned pairs of notches of said underside surfaces.

7. A method of assembling a longitudinally extending topwall sheet to a pair of longitudinally extending sidewall sheets wherein said topwall sheet and a longitudinal edge of each of said sidewall sheets are adapted to be joined together, said method comprising the steps of standing said pair of sidewall sheets upright and in a predetermined spaced-apart and substantially parallel relationship with respect to each other with said respective longitudinal edges thereof uppermost, said predetermined spacing being substantially equal to the transversely measured width of said topwall sheet, disposing an elongated tool in transverse direction with respect to said sidewall sheets and placing the tool in contact engagement at an underside surface thereof with both of said longitudinal edges of the sidewall sheets at a location spaced away from one end of the pair of sidewall sheets, said underside surface of the tool including a pair of spaced apart and transversely disposed guide means respectively receiving and retaining said longitudinal edges of the sidewall sheets, and said tool when so engaging said longitudinal edges retaining said predetermined spacing between said sidewall sheets, placing said topwall sheet in contact engagement with the opposite, upperside surface of said tool and substantially in position to be joined to said longitudinal edges of the sidewall sheets, placing one end of said topwall sheet in joining relation with respect to both of said respective longitudinal edges of the sidewall sheets at said one end of the latter, and progressively placing said topwall sheet in joining relation along its length with the respective lengths of said longitudinal edges of the sidewall sheets while to substantially the same extent progressively and substantially sliding said tool along the remaining lengths of said longitudinal edges of the sidewall sheets, said tool always being positioned ahead, in the direction of said progressive joining, of the location along the length of said topwall sheet which is then being so joined to said longitudinal edges of the sidewall sheets.

8. A method of assembling a longitudinally extending topwall sheet to a pair of lingitudinally extending side wall sheets wherein said topwall sheet and a longitudinal edge of each of said sidewall sheets are adapted to be joined together, said method comprising the steps of placing an elongated tool on a work-supporting surface, said tool including on its upperside surface a pair of transversely disposed channel means which are spaced apart a distance, along the length of said upperside surface, substantially equal to the transversely measured width of said topwall sheet, standing said pair of sidewall sheets upright with said longitudinal edges thereof uppermost and placing the respectively opposite longitudinal edges of said sidewall sheets each, respectively, in contact engagement with said pair of channel means of said upperside surface of the tool, said sidewall sheets extending substantially transversely with respect to the direction of elongation of said tool when so positioned and said channel means of said upperside surface of the tool receiving and retaining said opposite longitudinal edges of the sidewall sheets in said spaced apart relation with respect to each other, disposing another elongated tool in transverse direction with respect to said sidewall sheets and placing the tool in contact engagement at an underside surface thereof with both of said upwardly facing longitudinal edges of the sidewall sheets at a location spaced away from one end of the pair of sidewall sheets, said underside surface of the second mentioned tool including a pair of transversely disposed channel means which are spaced apart a distance substantially equal to the said transversely measured width of said topwall sheet and each of said pair of channel means respectively receiving and retaining said upwardly facing longitudinal edges of the sidewall sheets and said second tool, when so engaging said longitudinal edges, retaining the latter in said spaced apart relation with respect to each other, placing said topwall sheet in contact engagement with the opposite, upperside surface of said second tool and substantially in position to be joined to said upwardly facing pair of longitudinal edges of the sidewall sheets, placing one end of said topwall sheet in joining relation with respect to both of said respective upwardly facing longitudinal edges of the sidewall sheets at said one end of the latter, and progressively placing said topwall sheet in joining relation along its length with the respective lengths of said upwardly facing longitudinal edges of the sidewall sheets while to substantially the same extent progressively and substantially sliding said second tool along the remaining lengths of said upwardly facing longitudinal edges of the sidewall sheets, said second tool always being positioned ahead, in the direction of said progressive joining, of the location along the length of said topwall sheet which is then being so joined to said upwardly facing longitudinal edges of the sidewall sheets.

9. A method of assembling a longitudinally extending sheet metal cheek to a pair of longitudinally extending sheet metal wrappers to partially form a sheet metal duct section therefrom and wherein said cheek includes a downwardly turned flange extending along each of its side edges and each of said wrappers has a longitudinally extending pocket formed by folds of the wrapper material along a longitudinal edge thereof for receiving one of said downwardly turned flanges of the cheek, said method comprising the steps of standing said pair of wrappers upright and in a predetermined spaced-apart and substantially parallel relationship with respect to each other with said respect longitudinal edges thereof uppermost, said predetermined spacing being substantially equal to the transversely measured Width of said check, disposing at least one elongated tool in transverse direction with respect to said wrappers and placing the tool in contact engagement at a pair of parallel undersid surfaces thereof with both of said longitudinal edges of the wrappers at a location spaced away from one end of the pair of wrappers, said underside surfaces of the tool each including a pair of spaced apart notches respectively receiving and retaining said longitudinal edges of the wrappers, and said tool when so engaging said longitudinal edges retaining said predetermined spacing between said wrappers, placing said downwardly lturned cheek flanges in contact engagement with an opposite, upperside surface of said tool and substantially in position to be joined to said longitudinal edges of the wrappers, said upperside surface of the tool including a pair of spaced apart notches respectively receiving and retaining said downwardly turned flanges of the cheek, placing the respective of said downwardly turned flanges of the cheek at one end of said cheek within said respective pockets of the wrappers at said one end of the wrappers, and progressively placing said check flanges along their lengths within said respective pockets along their lengths while to substantially the same extent progressively and substantially sliding said tool along the remaining lengths of said longitudinal edges of the wrappers, said tool always being positioned ahead, in the direction of said progressive placing of the cheek, of the location along the length of said cheek which is then being so placed within said respective pockets of the wrappers, and said downwardly turned flanges of the cheek always being in said contact engagement with said tool.

10. A method in accordance with claim 9 comprising the further step of placing a second said tool in the same said contact engagement with said cheek and both of said longitudinal edges of the wrappers, said second tool being positioned at a second location spaced a substantial distance along the lengths of said wrappers away from the first said tool in said direction of progressive sliding movement of the first said tool.

References Cited by the Examiner UNITED STATES PATENTS 1/1949 Bennett D57l 3/ 1954 Lorentzen 2927t1

Claims

7. A METHOD OF ASSEMBLING A LONGITUDINALLY EXTENDING TOPWALL SHEET TO A PAIR OF LONGITUDINALLY EXTENDING SIDEWALL SHEETS WHERIEN SAID TOPWALL SHEET AND A LONGITUDINAL EDGE OF EACH OF SAID SIDEWALL SHEETS ARE ADAPTED TO BE JOINED TOGETHER, SAID METHOD COMPRISING THE STEPS OF STANDING SAID PAIR OF SIDEWALL SHEETS UPRIGHT AND IN A PREDETERMINED SPACED-APART AND SUBSTANTIALLY PARALLEL RELATIONSHIP WITH RESPECT TO EACH OTHER WITH SAID RESPECTIVE LONGITUDINAL EDGES THEREOF UPPERMOST, SAID PREDETERMINED SPACING BEING SUBSTANTIALLY EQUAL TO THE TRANSVERSELY MEASURING WIDTH OF SAID TOPWALL SHEET, DISPOSING AN ELONGAGED TOOL IN TRANSVERSE DIRECTION WITH RESPECT TO SAID SIDEWALL SHEETS AND PLACING THE TOOL IN CONTACT ENGAGEMENT AT AN UNDERSIDE SURFACE THEREOF WITH BOTH OF SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS AT A LOCATION SPACED AWAY FROM ONE END OF THE PAIR OF SIDEWALL SHEETS, SAID UNDERSIDE SURFACE OF THE TOOL INCLUDING A PAIR OF SPACED APART AND TRANSVERSELY DISPOSED GUIDE MEANS RESPECTIVELY RECEIVING AND RETAINING SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS, AND SAID TOOL WHEN SO ENGAGING SAID LONGITUDINAL EDGES RETAINING SAID PREDETERMINED SPACING BETWEEN SAID SIDEWALL SHEETS, PLACING SAID TOPWALL SHEET IN CONTACT ENGAGEMENT WITH THE OPPOSITE, UPPERSIDE SURFACE OF SAID TOOL AND SUBSTANTIALLY IN POSITION TO BE JOINED TO SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS, PLACING ONE END OF SAID TOPWALL SHEET IN JOINING RELATION WITH RESPECT T BOTH OF SAID RESPECTIVE LONGITUDINAL EDGES OF THE SIDEWALL SHEETS AT SAID ONE END OF THE LATTER, AND PROGRESSIVELY PLACING SAID TOPWALL SHEET IN JOINING RELATION ALONG ITS LENGTH WITH THE RESPECTIVE LENGTHS OF SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS WHILE TO SUBSTANTIALLY THE SAME EXTENT PROGRESSIVELY AND SUBSTANTIALLY SLIDING SAID TOOL ALONG THE REMAINING LENGTHS OF SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS, SAID TOOL ALWAYS BEING POSITIONED AHEAD, IN THE DIRECTION OF SAID PROGRESSIVE JOINING, OF THE LOCATION ALONG THE LENGTH OF SAID TOPWALL SHEET WHICH IS THEN BEING SO JOINED TO SAID LONGITUDINAL EDGES OF THE SIDEWALL SHEETS.