US1635658A - Reenforcing bar for concrete - Google Patents

Description

C. 5. BOARDMAN REENFORCING BAR. FOR CONCRETE July 12, 1927.

Original Filed Dec. 15. ,1921 2 Sheets-Sheet 1- IN VEN TOR A TTORNE Y Patented July 12, 1927.

'- UNITED STATES CHARLES S. BOARDMAN, OFlBUFFALO, NEW YORK.

nnnuronome BAR r03. conoien'rn.

Application filed December 15, 1921, Serial No. 522,499. Renewed December 8, 1926.

-This invention relates to reenforcing bars for concrete and is designed particularly with the object of producing an improved bar which may be successfully rolled and .6 which will possess additional and important advantages over the types of bars as heretofore used for concrete reenforcing.

An important and characteristic feature of my improved reenforcing bar is that it is composed of alternating portions or unit lengths of dissimilar cross-section wherein the alternation of cross-section affords the means for mechanical bonding entirely or to a substantial degree. My present invention further contemplates the production of a bar employing alternations of unit lengths of standard plain cross-section offering additional and important'advantages as will hereinafter appear. v

In the appended drawings wherein there are illustrated approved embodiments of the present invention, similar reference characters are employed to denote the corresponding parts in the several views wherein: a

Fig. 1 is'a side elevation of a bar embodying features of my invention. Fig. 2 is a. cross-sectional view on line 22 thereof. Fig. 3 is a similar cross-section taken on line 33. I i

Fig. 4 is a view in side elevation illustrating a modified embodiment of my improvements. v

Fig. 5 is a cross-section thereof on line 55.

Fig. 6 is a similar cross-section taken on line 66 thereof. I

' Fig. 7 is a view in side elevation illustrating a further modified bar made in accordance with the present invention.

Fig. 8 is a cross-sectional view thereof on line 8-8.

Fig. 9 is a cross-sectional view taken on line 9-9.

Fig. 10 is a side el'evational view of a further modification. V 1

"Figs. 11 and 12 are respectively cross-sections thereof taken on lines 1111 and 1212.

Fig. 13 shows inside elevation another modified embodiment of" my invention.

Figs. 14; and 15ers cross-sectional views thereof taken on lines l414 and 15-15 respectively.

My present invention in its simplest expression contemplates the production of a rolled bar of what may be termed multiple cross-section in that it is composed of suc-e each possessing specific advantages and meeting individual favor. My improved bar is specially designed to possess the important advantages of both types of bar, the respective sections of which it combines.

It furthermore offers the additional and important advantage of being adapted for use therewith of accessories designed for use with either type of cross-section of bar such as the various forms of supports and fastenings, for instance the commonly employed wire stamped metal fastenings used for holding the reenforcing bars in accurate position. As is readily appreciated my improved bar permits of the use of fastenings designed for either of the two cross-sections by assembling with either the square or round portions of the bar in the specific embodiment as illustrated- The length of the respective divisions or unit-lengths of the bar having uniform cross-section may be proportioned as desired, but preferably the length of the respective units may be one or more diameters of the bar and desirablyinay approximate three diameters of the bar, as illustrated.

The combined 'crosssect-ions as shown.

consisting of alternating unit-lengths of round and square cross-sectional contour are preferred both for the reason that these cross-sections are to a large degree stand ill ardiaed and owing to the circumstance that these related cross-sections IlVG approximately the greatest difference in cross-section, Col-respondinnly. in the described type of bar wherein the full mechanical bonding results from the change in crossseotion the prescribed cross-sections produce abar which would be more ditticult to pull out of concrete than most any other two cross-scctions that may be selected.

The cross-sectional areas of the respective unit bar lengths of dissimilar cro s section desirably are equal thereby prodncin; a bar of Substantially unit'orm properties as to strength. tension-a1 values. bending: moment. etc.. throughout its length. At the junctions of the two different cross-sections of bar additional metal i'iiiay be provided in the form of small fillets l. and 5 to compromise the respective sections over the junction area 3 and gradually reducing the extended portion of the bar length of one cross-section to the adjacent surface of the bar length ot dissimilar cross section. As exemplified in the llltlFilL'flilOl'lS the fillets at are reducing exten sions of the extendii'ig square or angular portions of the bar and the tillets are similarly associated with the extending round portions and converge with the squared surfaces.

The multiple bar construction as illustrated in Figure 1 essentially a deformed bar without corrugations or bosses, requiring but slight additional metal at each change t cross-sectioi'i in the form oi the described fillets. There is thus produced a concrete reentorcing bar having a sul'istantially uniform area. of cross section providing for mechani- -al bonding: without additional metal in the 'lorm ot' boss s and without deformation of thebarsurhlce.

In many of the reeni'orcimr bars previously designed and some of which have been rolled. the change in cross-section to produce the itletormations for mechanical bonding has been brought about by rolling); the leader he f and making the reduction in the cm sscetion by local indentures into the bar in the final pass of rolling. This type of bar has been proven to be structurally weak. First, the fibres of the metal in this change of cros, section have been sheared and destroyed in the reduced area of the bar. this reduction having been made in the finishing process when the bar has reached a low rolling temperature and has afi'ected the metal by compressing the fibres. intensifying the structure and melting a brittle bar.

This objectional local deiormation ot' the bar surface is avoided in my improved de sign of bar which tormatively allows oi the bar being; rolled to completion without imwiring the physical structure of the steel. In my design of bar the changeof crosssection is made by allowing the original metal to flow in the form of the bar and men bar ot my improved desiei'i moditicd to incor .)(n'ate therewith bosses or annular shoulders ti i'm'nicd at the junction o'i the dissimilar unit lengths o't bar in lieu of the lillets ot the first (llflt'lOSlll'G. In this modified Form the bo ses are formed to be non-projecting; beyond the greatest diai'nelter ot the plain bar sections.

Figs. (5 to 8 show a ilurther modified bar of this design with the bosses t3 oi" a diameter exceedingthe greatest projection oi either bar lei'ipgth from the center of the bar.

a bar ot comparativcly greater holding power in concrete is obtained by 1 bar havingrthesc cros sections alternating at regular intervals. with the additional metal in bosses placed at the junction of these two dill'ercnt cross-sections. making these bosses of larger diameter and using the additional metal only which would he used in the two or more corrugations oil the now ez ein e' recnlkircing bars.

in Figs. 10 to a suitable modification in the construction of my im uoved bar is illustrated to adapt it to be rolled by ungearcd rolls with corresponrlinc cormnercial ad.- vantage.

The torn'i oi? bar, an illustrated in Figs. ll) to 12 inclusive. may be obtained by a rolling operation employing roll:-; which are not; geared to accurately rotate Ill unison. This form ot bar is gl'el erally similar to the illustration oi Fig. 3. but wherein. in, adilition, there proridci'l and integrally rolled on the bar at o iposite sides a longitudinally extending: boss or rib T to which the boss ti are connected in continuity with their maximum diameters in the came cylimlrical plane oi of corresponding projection.

The provision oi the lzmgitudinal llll-l i'. which in the rolling; operation will, occur at: the division oil the rolls. allows oi the bar being termed by the riu pectii'e rolls with unsynnuetrical di position or relative posh tioninp; of the ho. or auction a ea-a upon the respective haires oi the bar. The bar produced may. therefore. correjptuul to the example illustrated in l i 'il?) to it) which is provided with the into longitudinal rib 7 and (he boL-ses upon the opposite rides of the center of the be r in dissimilar or non synnnetrical arrangement. .ls will be noted this bar is or a characterembodying the nu portant features of my invention in that it is a multiple bar structure conuiosell ot alternately arranged unit lengths of dissimilar ill) readable upon the-cross-sectional contour of one side of the baronl'y for as illustrated in the cross-sectional views of Figs. l t-and 15 the resulting full cross-sectional contour is substantially uniform but with the dissimilar surfaces reversely arranged. The invention may therefore be defined with particular reference to thisniodification as comprising a bar of the multiple characteristics described having longitudinally successive elongated plane parallel surfaces the alternate surfaces being provided by forming the bar of dissimilar and'plain cross-sectional con-- tour. 1 T

The described longitudinal rib 7 in addi tion to its function in connection with the rolling operation adds to the tensile strength of the bar and furnishes support and anchorage for the transverse ribs both during the rolling operation and in the finished bar.

I have thus produced an improved bar combining the characteristics and advantages of both the plain round and plain square cross-sections and providing for mechanical bonding in a more economical manner and avoiding the important objections to deformed types of bars as heretofore produced. In addition to the described advantages it may be added that my improved bar will be as effective against twisting in concrete as the commercial cold twisted square bars and, furthermore, by reason of its being a multiple of what may be termed plain sec tions, there are no objectionable depressions therein which would hold water with danger of corrosion of bars in storage. Also, as described there is provision made for substantially increasing the mechanical bond operatively occurring between the concrete and the bar, by reason of thechange of crosssection, considered with relation to the dissimilar cross-sections of uniform'cross-sectional area, so that a substantial degree of bonding is effected without additional metal.

In connection with the specific embodiment of my invention as here illustrated an additional commercial advantage may be obtained with relation to the customary practice of rolling square and round bar sections of sizes or diameters giving two sets of correspondingly different areas related to the respective sections. While my bar can be rolled to include all of these areas so that it can be applied in installations based upon the round bar or square bar calculations, it offers an instrumentality for compromising the sections with relation to the sizes or bonding areas allowing for the elimination of half the number of sizes of the respective sections and with a corresponding reduction in rolls required thereby reducing the cost of manufacture.

While I have illustrated and described typical embodiments of the features'ofmy present invention it will be understood that the same may be otherwlseand further modified without departing from the scope thereof and it is therefore intended that all.

matterherein shall be interpreted as illustrative and not 111 a limiting sense. In this connection it may be added by way of further example that the longitudinal rib type bar, as illustrated in, Figs. 10 to 15, conformlng generally in other respects to a non-projecting boss design of Fig. 4 may in similar manner be incorporated with the type of bar illustrated in Fig. 7 having the bosses in projecting arrangement.

The term plane in the foregoing description and in the appended claims is employed as generally descriptive of the regular or uninterrupted surfaces of both the unit lengths of square and round cross-section in that the surface of the latter is in a cylindrical plane.

Having described my invention I claim:

1. A'multiple section reenforcing bar of the character described comprising a bar having alternating unit lengths of dissimilar cross-section and formed with bosses positioned at the junction of the respective unit lengths substantially as described.

2. A reenforcing bar of the character de scribed comprising a bar having alternating lengths of dissimilar cross-sectional contour, the change of cross-section providing for mechanical bonding, each unit length of dissimilar section having plane longitudinal parallel surfaces and said bar being formed with additional metal at the junction of the unit-lengths providing junction areas of increased cross-section; Y

3. A reenforcing bar of the character described comprising a bar having alternating unit lengths of dissimilar symmetrical cross- 7 sectional contour, and having longitudinally parallel surfaces, each unit length extending longitudinally of the bar for a distance corresponding to at least the diameter thereof and said bar being provided" with bosses positioned at the unction of the unit lengths substantially as, described.

4. A multiple section reenforcing bar of the character described comprising a bar having longitudinally successive elongated plane parallel surfaces, the alternate surfaces being provided by forming the bar ofv dissimilar, symmetrical cross-sectional con 7 tour and having bosses formed at the junction of said successive surfaces, substantially as described.

5. A multiple section reenforcing bar comprising a bar having alternating unit lengths of plam square and plam round cross-sec- (i. A 1111111 iple section reen'forcing bur c0111- prisinp; a bar having alternating unit; length of plain square and plain round cross-sew (ion, The length of the respective units extending longitudinally of the bar a distance greater 1112111 the diameter of the bail, and said respective units having substantially equal cross-seetiol'iui are-n5, bosses formed on the her and positioned at the change of cross-section and providing junction por- 10 tions of increased err ss-seefionu1 area.

.Ln testimony whereof I have signed my name to this specification.

CHARLES 1"}. BOARDMAN.

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