US2985936A - Hanger assembly for suspended concrete forms - Google Patents

Description

B. HILLBERG May 30, 1961 HANGER ASSEMBLY FOR SUSPENDED CONCRETE FORMS Filed Jan. 4, 1960 INVEiTOR: BR OR HILLBE R6 Med ATT'Y United States Patent HANGER ASSEMBLY FOR SUSPENDED CONCRETE FORMS Bror Hillberg, Elmwood Park, 111., assignor, by mesne assignments, to Superior Concrete Accessories, Inc., a corporation of Delaware Filed Jan. 4, 1960, Ser. No. 252

8 Claims. (Cl. 25--131.5)

The present invention relates to hanger assemblies for concrete forms, such assemblies being employed for hanging concrete forms from bridge superstructures or the like. The invention has particular reference to a novel form of hanger assembly which, when under load in an actual installation, is devoid of destructive torsional, bending and other stresses which frequently result in disruptive strain in connection with conventional hanger assemblies designed for the same purpose.

Hanger assemblies of this general type are fairly well standardized in the industry, only a few typical forms of such assemblies being currently in use. Principal among such assemblies are what are known in the field as coil hanger frames and plate hanger frames, the former being designed for adjustment from below the concrete form deck and the latter being designed for adjustment from above the concrete form deck. Coil and plate hanger frames, respectively, are similar in their design and con struction, and each is in the form of an elongated framelike structure, made up of lengths of steel rod stock connected by welding at their ends to suspension devices through which the hanger or suspension bolts for the concrete forms are adaptedto extend. In the case of coil hanger frames, the suspension devices are in the form of wire coils which threadedly receive therein the contourthreads'at the ends of the suspension bolts. In the case of plate hanger frames, the suspension devices are in the form of flat plates having punched holes therethrough and on which the nuts associated with the threaded ends of the suspension bolts are adapted to be supported. The environment for both coils and plate hanger frames, respectively, is identical, the frames being supported at their end regions on the structural member (usually the upper flange or an I-beam) with the coils or the plates, as the case may be, overhangingthe opposite edges of the member. The suspension bolts are hung so to speak-from the coils or plates and the load is applied to and carried by the heads of the suspension bolts, utilizing suitable wide face washers to distribute the load.

Both coil and plate hanger frames of this general character are possessed of one serious limitation in that they are subject to disruptive deformation as the concrete of the suspendedform or forms. is being poured. Due .to the extremely great weight of the poured concrete, tremendous tension isapplied to the suspension bolts and, consequently, during pouring of the concrete, cumulative stresses-are applied not only to. the bolts themselves in the form of tensional application, but to the rods or frame members in the form of tortional application. Under full load, these stresses are such as to cause buckling of the frame members by an upward bulging thereof as the ends of the members .which overhang the top flange of the I-beam are weighted'down. In the case of coil hanger frames, the supported end regions of the frames creep inwardly on the supporting surface of the I-beams, thus shifting thecentersof the coils and also causing the axes thereof to become inclined. Bending and shearing stresses are thus applied to the suspension bolts and the latter P Ice 2,985,936

are greatly weakened, sometimes to the point where they will yield and give way. The same is true in the case of plate hanger frames, perhaps to an even greater degree inasmuch as the plates are less yielding than are the coils.

The present invention is designed to overcome the above noted limitation that is attendant upon the construction and use of both coil hanger frames and plate hanger frames for bridge superstructure concrete form support and, toward this end, the invention contemplates the provision of a novel form of hanger assembly or device having associated therewith means for preventing inward creeping or shifting of the supported end regions of the device on the top flange of the I-beam or other supporting surface so that the portion of the device which spans the I-beam flange will not buckle and so that, consequently, the suspension bolts associated with the device will receive only tensional stresses to the exclusion of lateral bending or shearing stresses.

This, being among the principal objects of the invention, it is a further object to provide a hanger assembly or device of this character which, in the place of conventional overhanging coil or plate suspension devices at the ends of the strut portion of the hanger, utilizes novel suspension means, such suspension means being of cagelike design and cooperating in the overall assembly in such a manner as to maintain the axes of the suspension bolts, which are passed therethrough, in parallelity and in respective vertical planes as the load on the bolts is progressively built up during pouring of the concrete.

A further object of the invention, in a hanger assembly of this general character, is to provide a unitary assembly which, exclusive of the suspension bolt assemblies associated therewith, is comprised of but three parts, namely a single tie rod or strut, and a pair of bolt-supporting cage devices at the ends thereof, such a structure resulting in economy in production in that the number of rod lengths required for the strut portion of the device is reduced to a minimum, while the welding operations required'to seventional hanger devices are completely eliminated.

Yet another object of the invention is to provide a hanger assembly of this sort having reinforced parts which, despite the fact that they are only three in number, will adequately support loads which conventional coil or plate hanger frames designed for the same'purpose are incapable of supporting.

With these and other objects in view, which will become readily apparent as the following description ensues, the invention consists of the novel construction, combination and arrangement of parts shown in the accompanying single sheet of drawings forming a part of this specification.

In these drawings: 1

Fig. l is a fragmentary sectional view taken substantially transversely and vertically through a typical suspended concrete form installation utilizing one of the hanger assemblies of the present invention;

Fig. 2 is an enlarged sectional view taken substantially along the line 22 of Fig. 1 with the concrete form removed.

Fig. 3 is a side elevational view of the assemblyof Fig. 2 showing the same operatively applied to a supporting member prior to concrete pouring operations;

Fig. 4 is a side elevational view similar to Fig. 3 illustrating the position assumed by cage-like suspension device of the hanger assembly after the concrete has been poured, i.e. with the load applied; and

Fig. 5 is an enlarged fragmentary detailed elevational view of a portion of the assembly shown in Fig. 4.

Referring now to the drawings in detail and in particular to Fig. 1, a hanger assembly constructed in accordanoe with the principles of the present invention has Patented May 30, 1961 been designated in its entirety at and it is shown as being operatively applied in a concrete form installation wherein the concrete form is hung from the upper horizontal flange 12 of an I-beam 14 associated with a bridge superstructure or other similar installation. The I-beam further includes a vertical web portion 16 and a lower horizontal flange 18. It will be understood that the I- beam may be supported in any suitable manner at its ends, or eleswhere, in the superstructure.

Briefly, the hanger assembly 10 involves in its general organization a steel or other metallic strut assembly 20 of elongated design and consisting of a single tie rod 22 having a pair of cage-like suspension devices 24 secured by welding to the opposite ends thereof. The suspension devices 24 are adapted to be supported on the upper supporting surface 26 of the I-beam flange 12 in the side edge regions respectively of the latter and they are adapted to receive therethrough suspension nut and bolt assemblies 28, by means of which the concrete form assembly 30 is supported from the I-beam 14.

The type of concrete form assembly capable of being supported from the nut and bolt assemblies 28 will vary for different installations and, in the form selected for illustration, horizontal deck plates 32 underlies the edges of the I-beam flange 12 as shown in Fig. 1, and are supported directly on structural beams 34 which, in turn are supported at their ends on longitudinal structural members or beams 36. The beams 36 are supported by the assemblies 28 in a manner that will be made clear presently. Irrespective of the particular nature of the concrete form with which the present hanger assembly 10 may be associated, the essential features of the invention are at all times preserved.

The tie rod 22 is in the form of a straight single length of steel rod stock having opposite end regions 40 which are welded as at 41 to the suspension devices 24 respectively in a manner that will be discussed after the nature of the devices 24 has been made clear.

The two suspension devices 24 are identical in construction and therefore it is believed that a description of one of them will sufiice for the other. Each suspension device 24 is in the form of a length or loop of flat sheet metal plate stock bent as best seen in Fig. 2 to provide a curved bight portion 42 and a pair of generally parallel side portions 44 and 46 respectively. The side portions 44 and 46 are each formed with a series of oflset ribs 48, 50, 52' and 54 respectively, all of these ribs extending substantially vertically in the position in which the assembly 10 is illustrated in Figs. 3 and 4. The ribs 48' and 54 extend completely across the side portions 44 and 46, the rib 48 being instruck and the rib 54 being outstruck. The ribs 50 are instruck and they extend partially across the side portions 44 or 46, as the case may be, in which they are formed and they extend downwardly from the upper edges thereof. The ribs 52 are outstruck and they extend partially across the side portions from the lower edges thereof. The pairs of ribs 48 and 50 receive the end regions 40 of the rod 22 therebetween and it is to these ribs that the rods are welded as at 42. The main body portion of the side portions 44 and 46 of the suspension devices 24 are thus slightly spaced from the end regions 40 of the rod 22. All of the ribs 48, 50, 52 and 54 constitute reinforcing ribs which lend rigidity to the suspension devices 24 as a whole.

The blank from which each suspension device 24 is formed has not been illustrated herein but it may readily be visualized. It is so shaped that in the completed device, which may be produced by a combined stamping and punching operation, the generally U-shaped structure is provided with a relief opening or hole 60 in the bight portion 42 thereof. The lower edge of the bight portion 42 is relieved as at 62 on an upward and outward incline, while the distal edges of the side portions 44 and 46 are similarly relieved as at 64 on an upward and inward incline, the edges being generally sinuous or wavy.

In the free state of the strut assembly 20, the upper edge of each U-shaped suspension device 24 is inclined outwardly and upwardly at a small angle relatively to the horizontal axis of the tie rod 22, while the lower edge thereof is provided with two series of teeth 70 thereon, these teeth being arranged in two rows, one on each side portion 44 and 46 respectively of the U-shaped suspension device. The four series of teeth 70 lie in a common horizontal plane. The teeth are of saw-tooth design, which is to say that they have vertical leading tooth edges 72 (Fig. 5) and inclined trailing tooth edges 74. The teeth 70 are not cutting teeth. They are merely traction teeth and they function in a manner that will be described subsequently to prevent inward shifting or creeping of the suspensions devices 24 when the latter are supported on the top horizontal flange 12 of the I-beam from which the concrete form installation is hung.

During the erection of the concrete form assembly, the strut assembly 20 is positioned as shown in Fig. 3 so that it rests upon the upper flange 12 of the I-beam 14 with the rod 22 extending transversely of the I-beam flange and with the two cage-like suspension devices 24 resting upon the upper face or supporting surface 26 of the flange 12 at the opposite longitudinal edge regions of the flange. The length of the rod 22 and the design of the cage-like suspension devices 24 is such that a major portion of the teeth 70 of each device rests squarely upon the supporting surface 26 while a few teeth, such as those which have been designated at 70a in Figs. 3 and 5, overhang the adjacent edge of the flange 12. The nut and bolt assemblies 28 are then applied to the devices 24 by threading a rela tively large size flat washer onto each bolt 82 so that the washer engages the head 84 of the bolt and then passing the bolt through the beams 36 and 34 and then through the deck plate 32 and finally through the vertical passage or opening 86 which exists by virtue of the curved bight portion 42 of the member 24, after which the nut 88 may be applied to the upper threaded end 90 ofthe-holt 82 and tightened from above the deck plate 32 as shown in- Fig. 3.

As the nuts 88 are tightened, the beams 36, 34 andthe deck plates 32 will be drawn upwardly by the washers 80 which are supported on the bolt heads as shown in Fig. 1. The various parts will thus be drawn together and the edge regions of the deck plates 32 will be securely clamped'between the beams 34 andthe underneath face of the upper horizontal flange 12 of the I-beam 14. With the parts thus in position it will be seen that the planes of the upper edges of the cage-like suspension devices 24 are inclined at a slight angle relative to the horizontal plane of the tie rod 22 as best seen in Fig. 3. The underneath faces of the nuts 88 will not seat squarely upon the upper edges of the devices 24 but rather they will seat only upon the bight portions 42 thereof. The apices ofthe teeth 70 however, with the exception of the overhanging teeth 70a, will seat squarely upon the upper face 26 of the upper flange 12 of the I"-beam 14. In this position of the parts, the suspended concrete form assembly is ready" for concrete pouring operations.

Referring now to Figs. 4 and 5, it will be observed that during concrete pouring operations, as the mass of concrete 92 (Fig. l) is progressively applied to the deck plates 32, the relatively great weight of the concrete places a heavy load upon the suspension bolts 82so that the nuts 88 are drawn downwardly on the bightportions 42 of the cage-like suspension devices 24 under the influence of such load. Due to the fact that the-nuts 88' do not seat squarely upon the. upwardly and outwardly inclined edges 66 of the suspension devices 24, but rather bear against the crests of the bight portions 42,- the points'of downward pressure upon the strut assembly'20as a' whole are the points of greatest overhang. Because'of this fact, as such downward pressure is applied to the suspension devices 24, the two.devices are caused'to. pivot, so to. speak, about the upper edges of the 'upper flange, 12 ofthe I beam 14in opposite directions, thus bringing the edges 66 to horizontal coplanar relationship as shown in Fig. 4. Due tame fact that the .teeth 70 are disposed an appreciable distance below the horizontal axis of the tie rod 20, this pivotal movement of the two suspension devices 24 creates a tendency for the two sets of teeth 70 to shift inwardly toward each other. However, because of the nature of the teeth,70, the latter are caused to dig-in so to speak, and displace the metal of the flange 12- as shown in Figs.i4 and 5 and resist inward shifting of the devices 24. This tendency for the devices 24 to shift inwardly is further resisted by the fact that the overhanging teeth 70a, which find no support on the upper face 26 of the I-beam flange 12, move downwardly below the plane of the upper face 26 of the horizontal flange -12 of the I- beam 14 and establish,'in eflect, vertical inwardly facing shoulders 94 (Fig. 5) which oppose the outside vertical side surfaces 96 of the flange 12 and bear thereagainst so that inward creeping of the devices 24 is resisted. Along the upper face 26 0f the flange 12, each vertical surface 72 of the series of teeth 70 constitutes in effect a vertical shoulder which opposes an increment of displaced metal so that inward shifting of the devices 24 is resisted by the sum. total of. a relatively largenumber of reaction forces.

It. should be'obs'erved that the radius of curvature of the bight portion 42 of each suspension device 24 is somewhat greater than'the radius of the shank portion of the bolt 28 which extends through this bight portion. Also, the distance between the bolt and the bight portion is greater than the diameter of the bolt. Thus, the bolt passes loosely through the suspension device so that the latter may pivot in the manner previously indicated without'causing binding of-the bolt. The upwardly and .outwardly inclined relief portions 62 afford additional clearance voids for the bolts 28 so that a large degree of tilting movement of the suspension devices 24 may take place without bringing the lower edges of the bight portions 42 into shearing engagement with the bolts.

It should also be observed that, in connection with each suspension device 24, a portion of the nut 88 overlies the outer region of the upper I-beam flange 12 so that when the weight of the poured concrete pulls the nut downwardly from the position wherein it is shown in dotted lines in Fig. 3 to the position wherein it is shown in full lines in Fig. 4, the suspension device 24 is gripped between the nut and the upper surface 26 of the I-beam top flange 12 in vice-like fashion and, at this time, the suspension device is held so that continued tilting movement thereof to such an extent that engagement between the bolt and the lower edge of the bight portion 42 is inhibited.

The teeth 70, being sharp so that they will readily dig into the metal of the upper flange 12 of the I-beam 14, and having the surface characteristics indicated at 72 and 74 and previously described, afford a very appreciable resistance to inward creeping movement on the flange surface 26. Such inward creeping movement of the suspension devices 24 is resisted, not by virtue of the teeth 70 alone, but also by virtue of the fact that when the upper edges of these devices are coplanar and horizontal as shown in Fig. 4, the lower edges thereof, which formerly in the free state of the strut assembly before concrete pouring operations were coplanar and horizontal, are inclined outwardly and downwardly as clearly shown in Fig. 5. In this condition of the suspension devices 24, the greatest downward pressure exerted upon the top flange 12 is along the outer longitudinal edges thereof so that each of these edges functions in the manner of a single tooth which digs into the metal of the adjacent suspension device, thus creating a shoulder at the junction of overhang of the device. The shoulders, thus created, assist in preventing inward creeping of the suspension devices 24.

The phenomena just described above is prevalent whether the teeth 70 are present or absent. If the teeth 70 are employed there is a mutual digging in of the parts.

I-beam and the suspension devices.

As shown in the drawing, the suspension devices 24. are of materially greater maximum height than maximumwidth. As the result of this, the tie rod 22 is disposed a substantial distance above the upper flange 12 of theI beam 14 and, hence, when the strut assembly is in use, the portion of the tie rod between the suspension devices is placed under such tension as the result of the load on the form-supporting nut and bolt assemblies 28 that it is not subject to any appreciable upward bending or distortion. By reason-of the fact that the portion of the tie rod: between the suspension devices is under tension when the strut assembly is in use and, consequently, is not subject to upward bending or distortion as the result of the load on the nut and bolt assemblies 24, the suspension i devices as a whole cannot tilt outwards and downwards to such an extent as to cause bending and resultant weak-I ening ofthe'up'per' ends of the shanks of the bolts.

While one specific'embodiment of the improved hanger assembly, constructed in accordance with the principles of.

the present invention, has been shown and described here in for illustrative purposes, it will be understood that the illustrated formof the invention does not indicate all the.

different forms suitable for the functions intended, the form illustrated b'eingonly one of those which have been.

developed for commercial application. It will be understood therefore that the invention is not to be limited to: the form disclosed and it is intended to cover all modifications and alternative constructions falling within the,

spirit and scope of the invention as expressed in the appended claims.

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

l. A three-part strut assembly adapted to rest on and extend transversely of the top flange of a substantially horizontal metallic I-beam or like structure and to support at the sides of the beams a pair of vertically extending form-supporting bolts having nuts at the upper ends of their shanks, said strut assembly comprising a single elongated horizontal tie rod of strong rigid metal and a pair of separately formed suspension devices at the ends of the tie rod, said suspension devices being formed of elongated strips of stamped strong rigid metal of appreciable width and bent medially of their end edges to provide U-shaped structures having substantially parallel side portions and intermediate connecting bight portions, the ends of the tie rod projecting between and being welded to said side portions of the suspension devices in close proximity to the upper edges of the latter and defining, in combination with said suspension devices, closed loops presenting vertically elongated openings for receiving with but comparatively little lateral looseness the shanks of the bolts, said strut assembly being of such length that when it is in its operative position with respect to the I- beam the lower edges of the inner regions of the side portions of the suspension devices seat on the upper face of the upper flange of the I-beam and the outer regions of said side portions together with the bight portions overhang the longitudinal edges of said upper flange, the upper edges of the overhanging parts of the suspension devices being designed and adapted to underlie the underneath faces of the nuts, said overhanging parts of the suspension devices being adapted when the nuts are tightened and the forms which are supported by the bolts are loaded to be forced downwards to a slight extent to the end that the lower edge portions thereof extend below the level of the upper face of the upper flange of the I-beam and thereby prevent inward shifting of the suspension devices with respect to said upper flange, said suspension devices being of such materially greater maximum height than maximum width that when the strut assembly is in use, the tie rod is disposed a substantial distance above the upper flange of the I-beam with the result that the load on the bolts places the portion of the tie rod between the suspension devices under appreciable tension thereby preventing it from being subject to any appreciable upward bending and resultant outward and downward tilting of the suspension devices as a whole.

2. Astrut assembly as set forth in claim 1 and wherein the upper edges of the side portions of the suspension devices areinclined outwardly and upwardly at such an acute angle with respect to the horizontal plane of the tie rod that when the overhanging parts of said suspension devices are forced downwards to their normal extent, said upper edges provide horizontal, nut-receiving surfaces against which the underneath faces of the nuts seat squarely.

3. A strut assembly as set forth in claim 1 and wherein the side portions of each suspension device are instruck in certain regions thereof to form spaced vertical ribs on the inside faces thereof, and such ribs are welded to the side portions of the adjacent end of the tie rod.

I 4. A strut assembly as set forth in claim 1 and wherein the lower edge portions of the connecting bight portions are inclined upwardly and outwardly to provide antishear relief regions for bolt-shank clearance purposes.

' 5. A strut assembly as set forth in claim 1 and wherein each of the side portions of each suspension device has formed along the lower edge thereof a row of downwardly projecting teeth adapted to bite into the metal of the upper flange of the I-beam when the concrete forms are loaded.

6. A strut assembly as set forth in claim 5 and wherein each row of teeth is fully coextensive with the lower edge of the side portion of the suspension device on which it is formed so that certain of the outermost teeth of the row overhang the adjacent side edge of the upper flange of the I-bearn.

7. A strut assembly as set forth in claim 5 and wherein each row of teeth is gqn rally of saw-tooth design and embodies vertical inwardly facing edges and inclined outwardly facing edges.

8. A strut assembly as set forth in claim 6 and wherein the upper edges of the side portions of the suspension devices are inclined outwardly and upwardly at such an acute angle with respect to the horizontal plane of the tie rod that when the overhanging parts of said suspension devices are forced downwards to their normal extent, said upper edges provide horizontal nut-receiving surfaces against which the underneath faces of the nuts seat squarely.

References Cited in the file of this patent UNITED STATES PATENTS 459,513 Montz Sept. 15, 1891 1,651,787 Venable Dec. 6, 1927 1,851,353 Dickman Mar. 29, 1932 2,215,972 Mueller et al. Sept. 24, 1940 2,722,045 Yates et al. Nov. 1, 1955 FOREIGN PATENTS 358,708 Great Britain Oct. 15, 1931 OTHER REFERENCES Engineering-News Record Article, page 56, Aug. 29, 1957.

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