US2955687A - Nailable flooring - Google Patents

Description

I Oct. 11, 1960 M. c. SEIM NAILABLE FLOORING 4 Sheets-Sheet 1 Filed 001;. 5, 1956 INVENTOR. 772a 9/2 a r4 6. 566m,

M. C. SEIM NAILABLE FLOORING Oct. 11, 1960 4 Sheets-Sheet 2 Filed Oct. 5, 1956 INVENTOR 7 77Zay/2ard C Sez'm, 44 %58 BY Oct. 11, 1960 M. c. SEIM NAILABLE FLOORING 4 Sheets-Sheet 3 Filed Oct. 5, 1956 g- INVENTOR.

Way/20rd 6 596172,

Oct. 11, 1960 M. c. SEIM NAILABLE FLOORING Filed Oct. 5, 1956 4 Sheets-Sheet 4 INVENIOR 3 62 717,

Way'nard'' ATTORNEY ized imp'ac-t loads.

2,955,687 Prifitd FF- 2 .5

Uni d S t s Pa? NAILABLE FLOORING Maynard C. Seim, Nankin Township,.Wayne County, vMicl1.,.assignor to National Steel Corporation, a cor- The present invention relates to improvements in floors, particularly the floors of freight carrying conveyances, andrelates to improvements in metal structural members which may be readily assembled side by side to form a floor which presents tortuous nail receiving and bending grooves between the adjacent sides of the members for the fastening thereto of blocks or other members'to prevent the shifting of the freight in the conveyance.

The present invention will be described more particularly in connection with truck conveyances which includes trucks and trailers. The principles of the presentinvention are applicable to other floors-'fofekample, the

floors ofrailro ad freight cars, airplane cabins and the decks ofships. The structural members may also be assembled to form a side wall or ceiling, and in this specification and claims the term floor may be taken to include side wall and ceiling where not inconsistent with the context.

In the past, trucks and other freight carrying conveyances have been constructed with either wood or metal floors. Blocks or other means for preventing the shifting of the freight cannot be readily fastened to the metal floors. On the other hand, if blocks are nailed to the wooden floors in the truck, then the floor is quickly damaged and it is not longuntil it must be replaced.

In conveyances, and particularly in trucks and airplanes, the weight of the'structure should be kept to a minimum while providing the necessary high strength and loadsupporting capacity. The floor in a truck supports a load of many tons and, at-least at times, this load is not uniformly distributed over the floor. when carrying machinery or other heavy objects, the load may be concentrated in a relatively small area of Particularly the floor. At times, the floor is subjected to large local- For these reasons, the fioor'must be capable of. supporting a relatively large load distributed over. its entirearea 'and must be capable of supporting large loads where the weight of the loads is concentrated in a small area. In addition to this high load supporting capacity, the truck floor should be as light as possible so as to keep the tare weight at a minimum.

Nailable metal floors have been provided in freight carrying conveyances such as railroad freight cars by arranging metal channel members side by side to form the floor. These channel members have load supporting deck portions and side Webs depending from and extending along the opposite lateral edges of each of the deck portions. One side Web is provided with a nail bending male rib and the other side web is provided with a nail bending female rib. The nail bending ribs extend lengthwise of the member and are complementan'ly' curved. When a plurality of these channel members are arranged side' by side with the male and female side webs in opposed spaced apart relationship, each two contiguous side webs define therebetween a tortuous groove into which nails can be driven and gripped. While such metal floors are a distinct improvement, it has been necessary to form the channel rnembers out of relatively heavy metal so that the floor will have the necessary load supporting capacity. 5 This excessive weight is undesirable in freight cars and other conveyances and is particularly undesirable in trucks and airplanes as it decreases the paying load which can be hauled. For these reasons, the nailable metal floor structures used heretofore injrailroad freight cars have not been entirely satisfactory in allapplications, and this is especially pronounced when attempts have been made to install similar nailable metal flooring in trucks Y It'is an object of the present-invention to provide improved metal structural members'that can be readily assembled side by'side to form a floor, orother surface structure, that is relatively light inweight and that will support a relatively large uniformly or non-unifo'rmly'distributed load. Y f Another object of the present invention is to provide improved metal structural members so constructedthat the members when assembled side by side on' spaced supports will provide a relatively light weight floorlthat will support a heavy load applied to a relatively small, local-' ized area of the floor. Another object of the present invention is to provide improved metal structural members constructed and arranged to make maximum use of themetal-so'that the various portions of the members willmutually contribute to the load supporting capacity'of the member and of thefloor. Another object of the present invention is to proyide in a conveyancean improved floor, or similar wall structure, made up of improved metal structuralfni'embe'rs mounted on spaced apart laterally'extending, cross mem bers.

These and other objects and advantages of the present invention will become more re'adily'apparent from the following description, taken with theaccompanying drawings illustrating a preferred form of the; invention, 'in which: I

Figure l is an isometric view of a portion of a truck floor structurev embodying the principles of the present invention; portions of the structure have been removed better to illustrate the arrangement of the parts;

Figure 2 is an enlarged cabinet view of one of the floor ing members'of Figure 1-;

Figure 3 is an enlarged fragmentary in section, of the structure of Figure 1; Figure 4 is an enlarged fragmentary plan view of a portion of one of the floor members of Figure 1; Figures 5 and 6 are fragmentary sectional views taken along lines 5--5 and 66, respectively, of Figure'4 Figures 7 and 8 areenlarged, fragmentary sectional views of a portion of the structure shown in-Figure 3;

Figure 9 is an enlarged fragmentary sectional view taken along line 9-9 of Figure 7; Figure '10 is an enlarged, fragmentary'sectionalview similar to Figure 7 and illustrating a modification also embodying the principles of the present invention; Figure 11 is an enlarged fragmentary end view, par tially in section, of a floor structure constructed in accordance with another embodiment of the present invenend view, partially tion; and a Figures 12 and 13 are enlarged, fragmentary sectional views of a portion of the structure shown in Figure 11.

Referring to the drawings, the floor 10 comprises 'a framework includes spaced apart cross members 12, or their equivalent, extending transversely of the floor members, for supporting the floor members 11.

'The floor members 11 may be formed of sheet metal by means of rolls or dies or in any suitable manner. Each member 11 includes an upper, substantially horizontal, load supporting deck portion 16 having the two opposite lateral edges 17 and 18, respectively. A side web 20 extends along and depends from the lateral edge 17 of the deck portion while a side web 21 depends from the opposite lateral edge 18 of the deck portion 16. The side webs 20 and 21 are parallel and the plane of each side web is vertical and normal to the plane of the deck portion. Each of the side webs 20 and 21 is integrally joined along its lower edge to an inwardly turned foot portion 22, 23, respectively. Thus, each floor member is in cross section substantially channel shaped with inwardly turned flange portions 22 and 23. Flanges 22 and 23 strengthen the member and provide bearing surfaces for engagement on the supports 12.

In the deck portion 16of each member 11, there are a plurality of parallel, concave or depending reinforcing ribs 25. 'Each rib 25 extends laterally across the deck portion and from side web 20 to side web 21. The ribs 25are spaced apart along the length of the deck portion so that the deck portion is made up of alternately arranged concave ribs 25 and convex ribs 26.

The side Webs 20 and 21 include complementarily curved nail bending ribs arranged so that when the floor members 11 are contiguously arranged side by side on the cross members 12 with their respective side webs 20 and 21 in contiguous, spaced apart relationship and with the deck portions 16 coplanar, as shown in Figures 1 and 3, each two contiguous side webs 20 and 21 define therebetween a tortuous nail receiving and bending groove 27.

' Referring more particularly to Figures 7 and 8, the

metal at the juncture of the side web 20 with the deck portion 16 is curved about the center 30 to provide a rounded shoulder portion 31. The side web portion 21 is similarly joined to the deck 16 by a rounded shoulder 32 curved about the center 33. The rounded portions 31 and 32 define therebetween a divergent, nail guiding entering throat 34 for the nailing groove 27. The upper edge portion of each of the side webs 20 and 21 preferably are provided with relatively fiat, straight portions 35 and 36, respectively, to provide the nailing groove 27 with a relatively straight portion 28 adjacent the nail guiding entering throat 34. The fiat portions 35 and 36 which are located in the planes of their respective side webs may be omitted but are pfeferred for better guiding of the nails into the groove. The straight groove portion 28 aids in maintaining the nail erect as it is driven into the groove and prevents a nail driven into the groove at an angle from piercing the side web. The metal at the bottom of the outer end of each rib 25 is curved at its juncture with the respective side web 20 or 21 to present a rounded shoulder 37 curved about a center 38. The shoulders 37 present a divergent entering throat between opposed ends of the ribs 25 that is similar to 34. The nailing groove 27 has a nail guiding and entering throat extending along substantially the entire length of the groove and the straight portions 35 and 36 preferably extend below centers 38 so that straight portion 28 extends along the length of groove 27.

Each of the side webs 20 and 21 includes a pair of nail bending ribs, one above the other. The side web 20 includes an upper nail bending, male rib and a lower nail bending female rib 41. The other, opposite side web 21 includes an upper nail bending, female rib 43 and a lower nail bending, male rib 44. The two pairs of ribs are disposed opposite each other and each two opposite ribs 40 and 43 and 41, 44 are complementarily curved. Thus, when the members 11 are arranged side by side with their respective side webs 20 and 21 in contiguous, spaced apart arrangement, the complemem tarily curved female and male ribs 41 and 44 of two contiguous side webs are in opposed, spaced relationship so that when a nail 45 is driven into the nailing groove 27, the entering portion of the nail is bent first to the left of the plane midway between the members which plane is indicated by line 46, Figure 7. Thereafter, the nail is bent back through and to the right of this plane and thereafter back to and then to the left of plane 46. Thus, the nail is bent through two reverse curves. The numerous advantages of having at least two or more nail bending ribs in each side web portion will be more fully hereinafter described.

I have discovered that in order to obtain the arrangement and construction of the reinforcing ribs 25 which provide the strongest flooring member 11, it is necessary to take into consideration the effect of and the arrangement of the nail bending ribs in the side webs 20 and 21. I also have found that the reinforcing ribs and nail bending ribs can be proportioned and arranged so that both types of ribs mutually contribute to better use of the metal in the members. This means that a floor can be provided which is relatively lighter but stronger than the nailable floors which have been proposed in the past.

In order to facilitate a better understanding of the present invention and before discussing the present improvements in more detail, attention is called to a number of factors which must be taken into consideration when considering the load supporting capacity of the floor. When considering the load supporting capacity of the floor, the load supporting capacity of the individual members must be taken into consideration. This is especially the case with the floors of trucks and other conveyanecs where a heavy load is, at least at times, concentrated or localized in a relatively small area. Thus, a large load may be applied to a relatively small area of the deck of a single floor member 11. In considering the load supporting capacity of the fioor member 11, it is to be noted that the side webs 20 and 21 are spaced apart beams connected at their upper edges by a plate or deck portion 16 and that these beams 20 and 21 are supported at spaced points along their length. Furthermore, the deck portion 16 is a beam supported at its ends on spaced columns 20 and 21. Directly above a cross member 12, the member 11 is substantially solely a beam 16 supported at its ends on spaced columns. When the load is applied at a point midway between the cross members, the spaced apart beams 20 and 21 supported at their ends by the adjacent cross members 12 are subjected to the largest bending moments. While these factors vary, depending upon the portion of the member under consideration and under load, in determining the strength or load supporting capacity of member 11, its load supporting capacity must be determined by considering it as a pair of laterally spaced apart beams 20 and 21 supported by spaced supports 12 and as a beam 16, supported at its ends on crooked columns 20 and 21.

Heretofore, the general practice has been to consider the nail bending ribs as a total liability and that the member has little, if any, strength when considered as a beam 16 supporting at its ends on columns 20 and 21. This viewpoint has been caused by the fact that the side webs or columns 20 and 21 contain laterally displaced metal or nail bending ribs so that the columns are crooked or partially collapsed. Thus, supporting columns 20 and 21 for beam 16 will support less load than they would if they were flat or if they contained vertical ribs. There has been a failure to realize that the nail bending ribs are a benefit and that the nail bending ribs can be arranged to provide strong columns.

In the past, it has been at times deemed advisable to provide reinforcing ribs in deck portion 16, and it has been the practice to extend the ribs only part way across the deck for a number of reasons. The greatest amount of sag takes place at the center of the deck portion so that it has been believed that ,by pioviding a re-' inforcing rib extending only across the mid-portion of thejdeck portion would be satisfactory. While proposals have been made to extend such a reinforcing rib all the way across the deck portion 16, it has not been the practice to do this and, insofar as is known, has never been done for the reason that extending the ribs from side web to side web weakens the side webs as beams mounted on spaced supports. In other words, the ribs when extended entirely across the deck portion reduce the height of the side webs and the amount of metal in the side webs, and, therefore, the side webs are weaker beams.

'In accordance with the present invention, the reinforcing ribs 25 are constructed and arranged to provide maximum strength in the deck as a beam supported on collumns by taking into consideration the fact that the nail bending ribs distribute a locally applied load 'over a greater area of the side web 20 or 21 when considered as beams supported at spaced points along their length. Thus, the nail bending ribs counteract the weakening effect of the reinforcing ribs.

Referring more particularly to Figures 2 to 6, inclusive, the reinforcing ribs 25 are identical and only one will be described in detail. The rib 25 includes .a midportion 48 and the outer end portions or shoulders 39 adjacent the side webs and terminatingin the curved shoulders 37. The deck or beam 16 has depthwith metal above and below the neutral axis and is a beam as distinguished from a plate. Extending'the rib 25 to the side webs 20 and 21 weakens the side webs 20 and 21 as beams, but I have found that the nail bending ribs in the side webs stilfen the side webs and distribute va load applied to a limited area of the 'deck portion over the side webs, that is substantially one-third the maximum depth of .the mid-portion. The relatively shallower outer end portions may be connected to the relatively deeper mid-portion 48 by the inclined portions 51 and 52. The mid-portion is substantially semi-circular in cross section, and the end portions 39 are substatnially flat bottomed, relatively wide ribsin cross section. The rib end portions 39 are longitudinally rounded or curved at 37 as the ribs extend around the shoulder to the respective side webs. -As shown more clearly in Figure 5, the ribs 39 are preferably proportioned so that at the edges of the deck, the ribs 39 and 26 are of about equal width with about equal amounts of metal disposed above and below a plane midway between the top of ribs 26 and the bottom of ribs 39. Thus, by utilizing the load distributing efiect of the nail bending ribs, it is possible to extend the reinforcing ribs entirely across the deck portion 16 and from side web 20 to side web 21. Without the rib portions 39 in the lateral shoulders of the deck portion, the deck at its edges would be a fiat plate, and while the ribbed mid-portion would be stiffened, the deck portion would not have maximum strength as a beam.

Two or more nail bending ribs in each side web portion are preferred as they distribute a locally applied load over a greater'length of the side webs. I also have found that by having two or, more nail bending ribs in each saidweb, it is possible to arrange the ribs so that side webs 20 and 21.are stronger columns and stronger beams than when one rib only is provided in the side webs as has been the customary procedure.

When a load is applied uniformly downwardlyagainst the deck portion 16, an equal reaction is applied upwardly against the feet 22 and 23. The metal at the juncture of the side webs 20 and 21 with deck portion 16 is curved or rounded as shown at 31 and 32. The metal at the juncture between side web 20 and foot portion 22 is curved about center 50 to form a rounded shoulder 51. Similarly, side web 21 is joined to ,foot 23 by a rounded shoulder 52 curved about center 53. The load applied to deck 16 is not distributed over an area having a width equal to the distance between the side webs but is distributed over an area having a width equal to the distance between centers. 30 and 33. The limit of the load distribution is indicated by arrows L-L. Similarly, the limits of the reaction is indicated by arrows RR, Figure 9. Thus, a load and its reaction are not applied vertically against the ends of columns 20 and 21 and set up and 21. With only one male rib in side web 20 and one female rib in side web 21, it is necessary to displace the metal in the nail bending ribs to a greater extent than shown to provide the necessary bending and holding characteristics. Such an arrangement is shown in application Serial No. 139,259, filed January 18, 1950, by Raymond H. Shay. With single nail bending ribs in each side web portion, the metal in the male rib 40, for example, would be displaced at least a distance equal to the width of the groove 27 and the corresponding female rib 43 would be equally displaced.

Formation of the male rib displaces metal outwardly from the planes of R and L, and this increases the bending moments in the metal of the male rib. On the other hand, formation of a female rib displaces metal of the side web inwardly toward the planes of R and L and reduces the bending moments in the metal of the female rib. Accordingly, when there is. only one rib in each side web, the side web containing the male rib is .a weaker column than the side web containing the female rib. The member 11 is, of course, no stronger than its weaker side web.

I have found that providing two nail bending ribs in each side web enables me to provide side webs that are stronger columns, that are equal or more nearly equal in column strength and that are stronger beams so as to better compensate for the weakening action resulting from the formation of the shoulder reinforcing deck ribs 39. I also have found that it is especially important that two or more nail bending ribs be provided in each side web when the member is formed of sheet steelhaving a thickness less than 0.1 inch, for with light gauge steel, the column strength of the side webs is relatively less than with heavier gauge metal and is critical.

As shown more clearly in Figures 2 and 7, the male rib 40 is curved about center 55, and the maximum displacement of metal from the plane of side web 20 which is at the peak of rib 40, is equal to one-half the width of groove 27. The female rib 43 is complementarily curved about a center that coincides'with center 55 when the members are arranged contiguously with side webs 20 and 21 opposed. The maximum lateral displacement of metal. in rib 43 from the plane of side web 21 also is one-half of the Width of groove 27. Ribs 41 and 44 are similarly curved about center 56, and the maximum lateral displacement of metal is equal to onehalf the width of groove 27. Thus, the side webs 20 and 21 are stronger columns than when each side web includes only one nail bending rib as the maximum lateral displacement of metal is only one-half of that required with a single rib so that a load develops smaller bending momentsin the displaced metal and the columns 20 and 21 can support larger loads without collapsing. 1 Each side web contains both laterally outwardly and laterally inwardly displaced metal so that the side webs, in addition to being stronger columns, are columns of bending movements in columns 20 equal or substantially equal strength. The radius of curvature of the ribs 44 and 41 about center 56 is preferably a little longer than the radius of curvature of ribs 40 and 43 about center 55 so that the nail is bent through a relatively larger curve after being bent through a relatively smaller curve and work-hardened. The side webs would have equal strength as columns if the radii were equal, but the difference is so slight that for practical purposes it can be ignored and the columns can be considered as having equal strength. While the side webs are columns of substantially equal strength only when the side webs each contain only two nail bending ribs or a multiple of two, an odd number of ribs greater than two may be used, for with three or more ribs the difference is very much less than when only one rib is present.

In addition, if there is only one rib in each side web, the minor axis of the cross sectional area is located at one side of a vertical axis bisecting the top and bottom edges of the side web. In other words, the minor gravity axis does not coincide with an axis of the outline of the area so that as a loaded beam, the side web will tend to twist. With two nail bending ribs, the minor gravity axis more nearly coincides with the section outline.

Another advantage in having two nail bending ribs in each side web portion in place of one is that the nail 45 is bent through two reverse curves and is more securely held in place. With the nail bent through two reverse curves, a live load will not walk the nail out of the groove 27 as would happen with only one rib. While the nail is more securely held in place under a live load, the nail can be withdrawn by any suitable tool, such as a claw hammer, when desirable.

.When assemblying the members 11 in a floor 10, the members 11 may be correctly spaced apart by any suitable means and then fastened in place. Preferably, spacers are provided on the members so that special tools or techniques are not required for assembly. As shown more clearly in Figures 2 and 7, a plurality of spacers 57 are spaced apart along the length of side web 21. As the spacers are identical, only one will be described in detail. The spacer 57 may be formed in a suitable manner of metal displaced outwardly from the plane of side web 21. The spacer 57 presents an outermost flat surface 58 which extends from the peak 59 of male rib 44 upwardly and beyond the level of the peak 60 of male rib 40. Thus, when the two members are placed side by side with spacers 57 abutting the male rib 40 of the opposed side web 20, the contiguous side webs are correctly spaced apart to provide the groove 27, and the groove 27 has a width twice the maximum lateral displacement of the nail bending ribs. This necessarily results from the fact that the portion of surface 58 which is at the level of the peak 60 of male rib 40 is located in the same vertical plane as the peak 59 of rib 44 and ribs 43 and 44 are equally laterally displaced. The spacers may be formed in either side web. If the spacers are formed in side web 20, then the spacer will present a flat outer surface extending from the peak 60 of rib 40 downwardly and past the peak 59 of rib 44. The spacer surface 58 coincides with vertical plane 46 midway between the two members when assembled and one member can be removed without disturbing the adjacent members.

The members 11 are assembled so that together they increase the strength and rigidity of the conveyance. The flanges 22 and 23 are connected to the cross members 12 by welding as indicated at 61, or by other suitable means. The members 11 are also connected together along their upper spaced edges by bridge welds 62. The bridge welds 62 are spaced apart along the top of each of the nailing grooves 27 and each bridge weld extends between contiguous upper portions of the members. The bridge welds may extend between the ends of ribs 25 or the ends of ribs 26, as shown in Figures 1 and 3.

With this arrangement, the members 11 are connected together into a rigid structure that strengthens the conveyance. In addition, the bridge welds 62, and particularly the bridge welds located between cross members 12, increase the load supporting capacity of an individual member. If a load is applied to one member 11, the adjacent members 11 aid in supporting the loaded member. The bridge welds also connect the adjacent lateral edges of the deck portions and stiffen the side webs. If a deck portion of one member is overloaded so that the upper edges of the side webs of the loaded member tend to swing outwardly, the bridge welds prevent such movement.

Referring more particularly to Figure 3, the deck portion 16 is crowned to increase the stability or the member 11. By the terms crown or crowned is meant that at least the top portions of ribs 26 of the deck portion extend in an are about an axis parallel to the longitudinal axis of the member so that viewed in cross section the deck portion extends through an arc and is not perfectly flat. The amount of crown only needs to be relatively small and good results have been obtained with the center of the deck portion 16 about one-sixteenth of an inch higher than the lateral edges of the deck portion. Preferably, the rib 25 is crowned about the same axis.

The member may be formed out of sheet metal in any suitable manner, and the thickness of the sheet metal will depend on the loads to which it is to be subjected. I have found that the nailable truck floors are very strong when built with members 11 which are formed of sheet metal that is only about 0.063 inch thick and, insofar as I know, this is about one-half the thickness used in prior floor members.

When testing the ability of the present floor to support localized loads, I have found that the floor will support larger loads than was expected. I also have discovered that when a floor member 11 is subjected to a varying load and the deflection measured at the different loads, the deflection is a straight line or more nearly straight line function of the load over a large range of loads so that larger loads can be applied without undue deflection. Heretofore, the deflection has been a curved line function of the load which greatly reduces the load that can be applied safely. The length of the straight line function can be increased and the slope of the line can be decreased by stress relieving the member 11 after the sheet of steel has been shaped. This further increases the safe load that can be supported by the member. The term stress relieved means that the member has been heated to a temperature below its critical temperature for a period sufiicient to relieve at least part of stresses set up in the metal by cold forming and to permit the deformed ferrite crystals to return to their original form or to form more nearly like their original form.

Figure 10 shows adjacent portions of a pair of floor members similar to those shown in Figure 6, except that the members of Figure 10 have a greater height. Those portions shown in Figure 10 which are the same as the corresponding portions of Figure 7 are designated by the same reference numerals. In Figure 10, the side web portion 20 includes a fiat portion 64- between rib 41 and shoulder 51. Similarly, side web portion 21 includes a flat portion 65 between rib 44 and shoulder 52. With this arrangement, it is possible to produce a deeper member while using the same rolls to form the nail bending ribs.

In the embodiment of the invention shown in Figures 11, 12 and 13, the side webs 20 and 21 are differently formed in the region of their joint with respective foot portions 22 and 23 to provide another arrangement for correctly spacing apart adjacent elongated members 11 without requiring the use of special tools or time consuming techniques. This is accomplished by forming the lower ends; of the webs 2G and 21 so that when a. pair of elongated members 11 are placed in side by' side relationshipwith the spacers 57 abuttingthe male rib 40 the webs 20 and 21 contact each other at a point lying in a plane passing through the outermost flat surfaces 58 of the spacers 57. The webs 20 and 21 are formed in this manner while also providing two pairs of complementary male and female nail bending ribs in each web. With this feature of the invention the lower end of the nail bending groove 27 is substantially closed and plastic or mastic filler material may be more easily retained in the nailing grooves.

= In Figures 11, 12 and 13 those portions of the structural members which are similar to corresponding portions of the structural members shown in Figures 3 and 7 are designated by the same reference numerals. As shown, the side W613 20 includes a lower female nail bending rib 70 connected between the upper male nail bending rib 40 and the foot portion 22, and the web 21 includes a lower male nail bending rib 71 connected between the upper female nail bending rib 43 and the foot portion 23, the ribs 70 and 71 being complementarily curved. The lower end of the female nail bending rib 70 extends outwardly beyond the plane of the web 20 and is joined to the foot portion 23 by a curved portion 72, the outermost extremity of the curved portion 72 lying in a vertical plane passing through the outermost extremity of the upper male nail bending rib 40. The lower portion of the male nail bending rib 71 of the web 21 is also curved outwardly from the plane of the web 21 and is joined to the foot portion 23 by a curved portion 73, the outermost extremity of the male nail bending rib 71 lying in a plane passing through the outermost surface 58 of the spacer 57. With this arrangement when a'pair of elongated members are placed in ad jacent abutting relationship the webs 20 and 21 are automatically spaced from each other to provide the nailing groove 27 of proper width by a pair of vertically spaced contact points lying in a common plane perpendicular to the plane of the foot pieces 22 and 23. The nailing groove formed by adjacent webs of structural members for-med in this manner causes a driven nail to pass through two reverse curves as shown in Figure 13. With structural members of a depth equal to the depth of the structural members shown in Figure 7, the curvature of the nail affected by the complementary nail bending ribs 70 and 7 1 will not be as great as the curvature achieved by the ribs 41 and 44. However, maximum degree of nail bending may be obtained by increasing the over-all depth of the webs in a manner shown in'Figure 10. In this manner the ribs 70 and 71 may be formed to correspond to the ribs 41 and 44 before the ribs 70 and 71 are projected outwardly so as to abut at a point lying in a plane passing through the outermost surface 58 of the spacer 57 upon themembers being placed in contiguous side-by-side relationship.

In the form of the invention shown in Figures 1 1, 12 and 13 the nail bending ribs 70 and 71 in the region of their joint with the foot pieces 22 and 23, respectively, may be projected outwardly in the manner described above, throughout the entire length of the structural members. This arrangement provides an automatic spacer arrangement that extends throughout the length of the members and makes it possible to more easily correctly space adjacent members. Also, with this structure the lower ends of the nail receiving grooves 27 are substantially completely closed throughout their entire length and it is possible to more easily fill the nail receiving grooves with a suitable plastic or mastic filling material.

It is believed obvious that modifications may be made without departing from the spirit or scope of the present invention and accompanying claims. For example, the floor members 11 may extend acrossthe conveyance instead of lengthwise of the conveyance. With either arrangement, the members 11 will be supported in spaced cross members which extend laterally of the members 11. The floor structure may be used, for example, as a side wall although the greatest problems generally are involved in providing a satisfactory floor and the present members 11 are primarily intended to be used in conveyance floors. The lower portions of the side walls of trucks are subjected to heavy impact loads and the floor members 11 may, for example, be used in such a location. If desirable, the members 11 may be covered with an anti-skid surfacing material and a plastic ormasti'c filler may be used to fill the nailing grooves as long as the grooves are sufiiciently exposed to indicate their location. 7

This application is a continuation-in-part of applica-. tion Serial No. 246,053, filed September 11, 1951, for Nailable Flooring.

What is claimed is: 1. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having a longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; web means joined to and depending from the deck portion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion; rounded shoulder means along the longitudinal edges of the deck portion at the point of joining between the deck portion and the side webs; means for supporting the structural.member including a laterally directed foot portion joined to the web means; means for increasing the beam strength of the deck portion including a plurality of concave reinforcing ribs each extending laterally across the deck portion and-the shoulder means from side web to side web; nail bending means including a pair of longitudinally extending nail bending ribs in each side Web comprising metal laterally displaced with respect to the plane of each side web, the first side web including a male and female rib with the male rib located closer to the deck portion than the female rib, the second side web including a female and a male rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second being complementarily curved and having centers of curvature lying in a common plane parallel to the deck por tion, the female rib in the first side web and the male rib in the second side web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion;

and a plurality of spacers located at intervals along the length of a side web, each spacer presenting an outer flat surface normal to the plane of the deck portion and extending tangentially from the outer peak of a male rib across the point of maximum lateral displacement of metal inan adjacent female rib;

the structural member being adapted, when arranged in side-by-side spaced-relation with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side Web of another member, to form a tortuous nail receiving and bending groove between the members.

2. The structuralvmember of claim 1 further including 'a nail guiding throat portion in the plane of each side web adjacent to the rounded shoulder means adapted to form a nail guiding throat having a central axis which is tangential to the outer peak of a male rib and normal to the plane of the deck portion when the similar structural members are arranged in the side-by-side spaced relation.

3. An elongated structural member of sheet metal comprising: an elongated deck portion forsupporting a load having a longitudinal dimension greater than its lateral dimension and spaced longitudinal edges;

webmeans joined to and depending from the deck por tion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion;

rounded shoulder means along the longitudinal edges of the deck portion at the point of joining between the deck portion and the side webs;

means for increasing the beam strength of the deck portion comprising a plurality of concave reinforcing ribs extending laterally across the deck portion and the rounded shoulder means from one side Web to another; means for supporting the structural member including a laterally directed foot portion joined to the web means; nail bending means including a pair of longitudinally extending nail bending ribs in each side web comprising metal laterally displaced with respect to the plane of each side web, the first side web including a male and a female rib with the male rib located closer to the deck portion than the female rib, the second side web including a female and a male rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion, the female rib in the first side web and the male rib in the second side web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion; and spacing means including a plurality of pairs of contact points located on the Web means with the contact points of each pair lying in separate planes paralfel to the deck portion and each of the contact points lying in a plane normal to the deck portion and passing tangentially through the outer peak of a male rib;

the structural member being adapted, when arranged in side-by-side spaced relation with other similar structural members, with their deck portions coplanar and with the one side Web of a member adjacent to the other side web of another member, to form a tortuous nail receiving and bending groove between the members.

4. The structural member of claim 3 further including a nail guiding throat portion in the plane of each side web adjacent to the rounded shoulder means adapted to form a nail guiding throat having a central axis which is tangential to the outer peak of a male rib and normal to the plane of the deck portion when the similar structural members are arranged in the side-by-side spaced relation.

5. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; web means joined to and depending from the deck portion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion; rounded shoulder means along the longitudinal edges of the deck portion at the point of joining between the deck portion and the side Webs; means for supporting the structural member including a laterally directed foot portion joined to the web means; a nail guiding throat portion in the plane of each side web located adjacent to the deck portion; means for increasing the beam strength of the deck portion including a plurality of concave reinforcing ribs each extending laterally across the deck portion and the shoulder means from side web to side web; nail bending means including a pair of longitudinally extending nail bending ribs in each side web comprising metal laterally displaced with respect to the plane of each side web, the first side web including a male and a female rib with the male rib located closer to the deck portion than the female rib, the second side web including afemale and a' male rib'with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion, the female rib in the first side web and the male rib in the second side web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion; and a plurality of spacers located at intervals along the length of a side web, each spacer presenting an outer flat surface extending tangentially from the outer peak of a male rib across the point of maximum lateral displacement of metal in an adjacent female rib; the structural member being adapted, when arranged in side-by-side spaced relationship with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side web of another member, to form a tortuous nail receiving and bending groove between the members.

6. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having a longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; web means joined to and depending from the deck portion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion; rounded shoulder means along the longitudinal edges of the deck portion at the point of joining between the deck portion and the side webs; means for supporting the structural member including a laterally directed foot portion joined to the web means; a nail guiding throat portion in the plane of each side web located adjacent to the deck portion; means for increasing the beam strength of the deck portion including a plurality of concave reinforcing ribs each extending laterally across the deck portion and the shoulder means from side web to side web; nail bending means including a pair of longitudinally extending nail bending ribs in each side Web comprising metal laterally displaced with respect to the plane of each sideweb, the first side web including a male and a female rib with the male rib located closer to the deck portion than the female rib, the second side web including a female and a male rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side Web and the female rib in the second web being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion, the female rib in the first side web and the male rib in the second side Web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion; and spacing means including a plurality of pairs of contact points located on the web means with the contact points of each pair lying in separate planes parallel to the deck portion and each of the points lying in a plane passing tangentially through the outer peak of a male rib and extending across the point of maximum lateral displacement of metal in an adjacent female rib; the structural member being adapted, when arranged in side-by-side spaced relationship with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side Web of another-member, to form a tortuous nail receiving and bending groove between the members.

7. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; web means joined to and depending'from the deck por tion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion; a

means for supporting the structural member including a laterally directed foot portion joined to the web means; a. nail guiding throat portion in the plane of each side web located adjacent to the deck portion;

nail bending means including a pair of longitudinally extending nail bending ribs in each side web comprising metal laterally displaced with respect to the plane of each side web, the first side web including a male and a female rib with the male rib located closer to the deck portion than the female rib, the second side web including a female and a male rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion, the female rib in the first side web and the male rib in the second side web' being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion; 7

and a plurality of spacers located at intervals along the length of a side web, each spacer presenting an outer flat surface extending tangentially from the outer peak of the male rib across the point of maximum lateral displacement of metal in an adjacent female rib; the structural member being adapted, when arranged in side-by-side spaced relation with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side web of another member, to form a tortuous nail receiving and bending groove between the members.

8. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having a longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; Web means joined to and depending from the deck portion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion; means for supporting the structural member including a laterally directed foot portion joined to the web means;

a nail guiding throat portion in the plane of each side web located adjacent to the deck portion;

nail bending means including a pair of longitudinally extending nail bending ribs in each side web comprising metal laterally displaced with respect to the plane of each side web, the first side web including a male and a female rib with the male rib located closer to the deck portion than the female rib, the second side web including a female and a male rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion, the female rib in the first side web and the male rib in the second side web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion;

and spacing means including a plurality of pairs of con- 14 tact points located on the web means with the cont-act points of each pair lying in separate planes parallel to the deck portion and each of the contact points lying in a plane passing tangentially through the outer peak of a male rib and extending across the point of maximum lateral displacement of metal in an adjacent female rib; the structural member being adapted, when arranged in side-by-side spaced relation with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side web of another member, to form a tortuous nail receiving and bending groove between the members.

9. An elongated structural member of sheet metal comprising: an elongated deck portion for supporting a load having a longitudinal dimension greater than its lateral dimension and spaced longitudinal edges; web means joined to and depending from the deck portion including a first elongated side web joined to one longitudinal edge of the deck portion and a second elongated side web joined to the other longitudinal edge of the deck portion;

means for supporting the structural member including a laterally directed foot portion joined to the web means; a nail guiding throat portion in the plane of each side web located adjacent to the deck portion;

the first elongated side web and the second elongated side web each including a pair of longitudinally extending nail bending ribs, the first elongated side web including a male rib and a female rib with the male rib located closer to the deck portion than the female rib, the second elongated side web including a male rib and a female rib with the female rib located closer to the deck portion than the male rib, the male rib in the first side web and the female rib in the second side web being complementarily curved and having centers of curvature lying in a common plane parallel to the deck portion with the female rib in the second side web having a greater radius of curvature than that of the male rib in the first side web, the female rib in the first side web and the male rib of the second side web being complementarily curved and having centers of curvature lying in another common plane parallel to the deck portion with the female rib in the first side web having a greater radius of curvature than that of the male rib in the second side web, the structural member being adapted, when arranged-in sideby-side spaced relation with other similar structural members, with their deck portions coplanar and with the first side web of a member adjacent to the second side web of another member, to form a tortuous nail receiv ing and bending groove between the members.

References Cited in the file of this patent UNITED STATES PATENTS 1,941,967 Bell Ian. 2, 1934 2,028,554 Main Jan. 21, 1936 2,099,051 Clark et a1. Nov. 16, 1937 2,457,250 Macomber Dec. 28, 1948 2,667,243 Fenske Jan. 26, 1954 2,685,354 Collins Aug. 3, 1954 OTHER REFERENCES Railway Age, May 31, 1947, page 7.

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