US1763940A - Metal joist and the manufacture thereof - Google Patents

Description

June 17 1930.

A. C. WALLEN METAL JOIST AND THE MANUFACTURE THEREOF Eiled Oct. 8, 1927 Patented June 17, 1930 arias TIT priv- ARTHUR C. WALLEN, OF CHICAGO, ILLINOIS, ASSIGNOR TO BATES EXPANDED STEEL- TRUSS 00., OF EAST CHICAGO, INDIANA, A CORPORATIGN OF DELAW'ARE METAL JOIST AND THE MANUFACTURE THEREOF Application filed October 8, 1927. Serial No. 224,795.

The invention relates to metal joists or beams and the manufacture thereof.

The main objects of the invention are to provide a joist or beam which is formed of an expanded integrally flanged beam and which has its end portions formed to bring the point of intersection of the stress lines as close to the supported portions of the ends to increase the resistance against bending moment in the zones adjacent and inwardly of the supports for the ends, and to provide a method of forming an expanded joist or beam composed of integral memhere, by which the beam will be slitted so that the integral end portions of the web will be form-ed to give additional strength to the joist or beam against bending moment adjacent the supported end portions.

Other objects of the invention will appear from the description.

The invention consists in the several novel features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings: Fig. 1 is an elevation of an I-beam from which the joist is formed. Fig. 2 is a view showing the manner of slitting the beam before it is expanded. Fig. 3 is an elevation of the beam after it has been expanded. Fig. 4 is an elevation of a finished joist or beam. Fig. 5 is a section on line 55 of Fig. 4. Fig. 6 is a sec-.

tion on line 66 of Fig. 4.

The invention is exemplified in a joist or beam consisting of a longitudinal upper member comprising a vertical web a and a horizontal flange a? projecting laterally from both sides thereof and forming the top of the joist; a lower longitudinal member comprising a vertical web a and a horizontal flange a projecting laterally from both sides thereof and forming the bottom of the joist; a series of substantially parallel diagonal truss members (a between the vertical web of the upper and lower members and oppositely extending series of diagonal or truss members a between the webs of the upper and lower members and medially united with the diagonal members a All of these members are integral and are formed of an I-beam or bar A shown in Fig. 1, with upper and lower flanges correspondmg to the flange a and a In the manufacture of the joist the web of the beam is v first sheared to form an upper series of longitudinally aligned slits a with bonds or intact portions A between them, a lower series of aligned slits a with similar bonds between them, and a central or intermediate series of slits a which are staggered relatively to the slits-01 and a to leave bonds A longitudinally midway between the ends of the slits a and a and to form expansible strands (a These slits are arranged so that the end-slits of the lower series a will intersect the ends of the beam; and the metal of the web between said slits and the top and bottom flanges is otherwise left uncut to points some distance inwardly of the ends 'to. form portions @1 which portions bear on the structure, beam or wall supports. These portions are of a height equalto the aggregate height of the web a and the strands between slits m and at and between at and a which fo'rmthe diagonal members. The central slit-s 03 are omitted from the por tions of the. beam disposed inwardly of the portions (11 and adjacent thereto to provide additional reinforcement for the upper member of the beam portion a adjacent the supported ends thereof. By omitting these slits, diagonal tension members a of greater thickness than the strands of the other diagonal members are provided between the end portions a and the second diagonal or truss member of the joist, and these tension memhere are each of the aggregate height of two truss-members. As a result of this formation, the intersection of the stress lines in the upper member and the diagonal tension members a adjacent the ends are projected endwise closer to the ends of the joist so as to approximately reach or extend beyond the point of support, as indicated by dotted lines (0 in Fig. 4. This exemplifies a method of slitting the joist preparatory to expansion sothat the upper member will be reinforced by a diagonal truss member of additional height, adjacent the supported ends of the'joist. A characteristic of this methodand result is that the metal of the diagonals, which would otherwise form downwardly and outwardly extending diagonal members adjacent the ends of the truss, as in the criss-cross trussing of the central portion, and which. end diagonals are substantially non-stress member of the beam adjacent the end After the beam has been slitted as described,it is heated and the upper and lower flanges are spread apart in parallelism by suitable expanding mechanism to the shape shown in Fig. 3. This expanding operation will stretch and deflect the strands of the web formed by the slits, intodiagonal mem bers a a leaving their ends joined to the web. and their medial'portions. joined together. This forms acentral series ofdia- Zontal flange vertically where it is supported.

mond shaped openings in the web and permits the extent of expansion necessary to form a joist of the desired height. The slits 00 are spaced from the top of the joist a greater distance than the slits a are placed from the bottom of the joist, to give greater strength to the top portion of the joist. V Sufficient portions of the vertical web adjacent the ends are left to reinforce the upper, hori- By leavingthe ends of the webbetween slits a and the top flange unslitted, th e end portions of the upper member will be properly reinforced.

Struts a are placed and suitably secured,

as by welding or other means, between the upper and lower longitudinal members in the'o'penings nearest the ends of the joist,to'

act as compression members between said longitudinal members. These compression members are disposed; a suitable distance from the ends of the beam to directly transmit stresses between the upper and lower longitudinal members. the beam, small pieces a are cut from the web or a single out is made to connect shear cuts at with the ends of the end shear cuts a to permit expansion of the end diagonal members a p In a trussed joist, it has been found advantageous to support the. ends of the upper, longitudinal member and leave the lower member in suspension, and for this purpose, the lower member is sheared off at a (Fig. 3) after the beam has been expanded, so the upper members will project over a suitable support B, as shown in Fig. 4. This shear ing will remove suflicient metal from the Before expanding ends of the lower'longitudinal member so the latter will not bear or connect with the support and will therefore act only as a suspension member. Either plates or pieces a, sheared off the lower longitudinal members, are then welded on the bottom of the ends of the projecting end-portions of the upper member to form bearing plates for the upthe upper longitudinal members from cutting into the supporting wall or beam.

The invention exemplifies, a oist which is formed of a slitted-expanded bar or beam with diagonal truss members which serveas compression and tension members to increase prevent the lower edge of the portion a of the strength of the joists and. in which provision is made, by means of diagonal end tension members of increased height, for strengthening the end portions of the upper member and to project the points of intersection of the stress lines in the upper member and the tension members nearest the ends as near as possible to the ends of the joint and the supports therefor, to'prevent' sagging or bending of the joists in the zones disposed inwardly of the end portionsya joist in which this result is attained by utilizing the metal which would otherwise form a substantially non-stressed diagonal mem-; her; and also a method of attaining this re sult by the manner of slitting the beam prior to expansion, and without the necessity of adding non-integral reinforcement to the portions of the joist near its ends.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of'the invention. 1

The slitting may be advantageously done in a machine of thetype set forth an application filed by Albert J. Bates, Jr. Nov. 5, 1926, Serial No. 1l1,702, and the ex panding of the beam may be done in a machine of the type set forth in Patent No. 1,260,857 dated March'26, 1918.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent, is:

1. That improvement in the manufacture of expanded metal joists which consists in. slitting the medial portion of a flanged beam'to form a pair of longitudinal members and a series of expansiblestrands between and bonded to said members, and slitting the ends of the beam to form exs pansible strandsof greater height than the strands in the medial portion of the beam; and then expanding the beam to space the two members apart and form oppositely extending diagonal truss members in the medial portion and ends of the beam.

2. That improvement in the manufacture of expanded metal joists which consist in slitting the medial portion of a flanged beam to form a pair of longitudinal members and a series of expansible strands between and bonded to said members, and slitting the ends of the beam to form only single expansible strands of greater height than the strands in the medial portion 01 the beam; and then expanding the beam to space apart the longitudinal members and form oppositely extending diagonal truss members in the said medial portion and ends of the beam.

3. That improvement in the manufacture of expanded metal joists which consists in slitting the medial portion of a flanged beam to form a pair of longitudinal members and two intermediate and side by side series 01"" expansible strands with bonds between them selves and said members, and slitting the ends of the beam to form single expansible strands of greater height than the strands in the medial portion of the beam; and then expanding the beam to space apart the l01"l tudinal members and to form oppositely tending centrally joined diagonal truss members in the medial portion of the beam and single diagonal truss members adjacent the ends of the beam.

4;. That improvement in the manufacture of expanded metal joists which consists in slitting the medial portion of a flanged beam on three longitudinal lines to form an upper and a lower longitudinal member and two intermediate and side by side series of expansible strands with bonds between themselves and said members, and slitting the ends of the beams on the upper line to form single expansible strands of greater height than the strands in the medial portion of the beam, and then expanding the beam to space apart the upper and lower members and to form single diagonal truss members adjacent the ends of the beam and oppositely extending centrally united diagonal truss members in the medial portion of said beam.

5. That improvement in the manufacture of expanded metal joists which consists in slitting the medial portion of a flanged beam on three longitudinal lines to form an upper and a lower member and two intermediate and side by side series of expansible strands with bonds between themselves and said members, and slitting the ends of the beam on the lower line to intersect the end edges and form end-portions for the lower memher that are disconnected with respect to the ends of the upper member, and also slitting the ends of the beam on the upper line to form adjacent said end-portions single expansible strands of the combined height of two of the strands in the medial portion of the beam; and then expanding the beam to space the lower member and its end-portions from the upper longitudinal member and to form single diagonal truss members adjacent the ends of the beam and oppositely extending centrally united diagonal truss members in the medial portion of the bca1n.

6. That improvement in the manufacture of expanded metal joists which consists in slitting the medial portion of a flanged beam on three longitudinal lines to form an upper and a lower member and two intermediate and side by side series of expansible strands with bonds between themselves and said members, and slitting the ends of the beam on the bottom line to intersect the end edges so as to form end-portions for the lower longitudinal member that are disconnected with respect to the end-portions of the upper member, and also slitting the ends of the beam to form end slits in alignment with the top line and cutting the beam transversely between the inner ends of said end slits and the outer ends of the end slits of the intermediate line so as to form single expansible strands between the upper and lower lines; and then expanding the beam to space the lower longitudinal member and its end-portions from the upper member and to form single diagonal truss members adjacent the ends of the beam and oppositely extending centrally united diagonal truss members in the medial portion of the beam.

7. An expanded metal joist formed of a flanged beam and comprising upper and lower longitudinal members, oppositely ex tending diagonal truss members in the medial portion of the beam, formed integrally with said upper and lower members, and diagonal truss members adjacent the ends of the beam, also formed integrally with said upper and lower members, said end truss members being of greater height than the truss members of the medial portion of the beam.

8. An expanded metal joist formed of a flanged beam and comprising upper and lower longitudinal members, oppositely extending diagonal truss members formed integrally with said upper and lower longitudinal members and acting as tension and compression members in the medial portion of the beam, and single diagonal tension members only adjacent the ends of the beam, also formed integrally with said upper and lower members, said single tension members being of greater height than the truss members of the medial portion of the beam.

9. An expanded metal joist formed of an I-beam, said joist comprising upper and lower longitudinal members, oppositely extending centrally united diagonal truss members, formedintegrally with the-upper and lower longitudinalmembers and acting as tension and compression members in the medial portion of the beam and diagonal tension members only adjacent the ends of the beam, also'formed integrally with said upper and lower members, said end tension members being of greater height than the I centrally united truss members of the me 19 dial portion of thebeam, the ends of the lower longitudinal member being extended to underlie the end tension members.

10. An expanded metal joist formed of beam consisting of flanges anda web, said v joist comprising upper and lower longitudinal members each including One of the flanges and a web-portion, oppositely extending centrally united diagonal truss mem bers formed integrally with the webs of said 20 upper and lower members and acting as tension and compression'members in the medial portion of the beam, and diagonal tension members only adjacent the ends of the beam, said last mentioned tension members being formed integrally with the webs of said upper and lower members and substantially double the height of the centrally united trussmembers of the medial portion of the beam, the ends'of the web in theupper memher being of the aggregate height of the end tension members and the web in the medial portion of said upper member. V

Signed at East Chicago; Indiana, this 22nd day of July,'1927.

. ARTHUR C. WALLEN.

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