US2887130A

US2887130A - Anchor lug for pipe tension wire

Info

Publication number: US2887130A
Application number: US689323A
Authority: US
Inventors: Waldo R Kell
Original assignee: Cen-Vi-Ro Pipe Corp
Current assignee: Cen-Vi-Ro Pipe Corp
Priority date: 1957-10-10
Filing date: 1957-10-10
Publication date: 1959-05-19
Anticipated expiration: 1976-05-19

Description

May 19, 1959 w. R. KELL 2,887,130

ANCHOR LUG FOR PIPE TENSION WIRE Filed Oct. l0, 1957 United States Patent O 2,887,130 ANcHoR LUG Fon PIPE TENSION WIRE Waldo R. Kell, Los Angeles, Calif., assignor to `Cen-Vi-Ro Pipe Corporation, South Gate, Calif., a corporation of Delaware Application october 1o, 1951, serial No. 689,323

9 claims. (el. 13s-s4) The inventionrelates to molded concrete pipes and `has `particular reference to those pipes currentlyidentified as `degree to demonstrate the technique as practical and successful, have hadcertain shortcomings. It will be appreciated that in applying heavy wire of a gage suicient to apply acceptable tension to pipes or molded concrete cores, two, three, four and more feet in diameter, a wire of very ample diameter is needed. Also in view of such circumstances the aggregate tension to accomplish the intended purpose is many thousands of pounds and whatever anchoring lug or anchoring means is made use of must be one capable of being applied `in the first place while the wire is held under tension and mustnaturally be sumciently rugged in its grip on the wire and its grip t within the molded concrete mass to hold that tension with an acceptable degree of insurance under all the circumstances which may be encountered. n

In the first instance the anchor lug must be one capable `of being securely anchored in the molded concrete when the concrete is poured and permitted to set. vCertain limitations are inherent in the problem, `one. of them being the very denite maximum thickness of the core wall which requires that the concrete anchoring elements be shallow enough to be completely contained within the wall thickness leaving an adequate amount of protecting concrete on both sides. p

Another factor lies in the fact that the anchoring device must not be of such character as to protrude unnecessarily inasmuch as after the anchoring of zthe wire4 takes place, a protective outer coating of concrete `or other acceptable `plastic material must be applied to a 'depth capable of completely covering the `anchoring means. Also because of the wire being under very heavy tension, it is most needful to have the anchoring means one which can be quickly and easily engaged when the tension is at its greatest.

It is accordingly among the objects of the invention to provide a new andimproved anchoring means for the ends of Wire under tension when applied to concrete cores for prestressing purposes which is rugged in design and of such shape and proportions that it can be easily embedded in the core while at the same time providing facility for readily engaging the prestressing wire.

Another object of the invention is to provide a new and improved anchoring lug device which is preferably ush with the exterior surface of the core, `thereby making it possible to present a relatively unobstructed outer surface on the core for the subsequent application of a protective exterior coating.` p

ICC

Another object of the invention is to provide a new and improved anchoring lug means for prestressing wire which is positive in its application to the wire so that no slippage will occur during the making of the connection and which also is of such proportions that it can be embedded properly within the concrete core to a sufhcient depth from the opposite surfaces thereof.

Still another object of the invention is to provide a new and improved anchoring lug means for prestressing `wire which is of such character and proportions that it can be made to fit wire of varying diameters without need forchange inthe anchoring device itself.

Still another object of the invention is to provide a new and improved anchoring lug means which is of relatively simple construction and which is complete in itself when embedded in the core during the molding process such that it is immediately ready for the reception of the end of the wire to which an appropriate anchoring sleeve has been attached in a fashion and at a location such that the sleeve and Wire can be quickly and effectively slipped into engagement with the `embedded lug components and thereby make an immediate permanent connection. p

Still further among the objects of the invention is to provide a new and improved anchoring lug means which is extremely simple and inexpensive inits construction and assembly and which is also of such character that a dependable anchoring attachment can be made very rapidly in such form that its effectiveness is assured.

With `these and other objects in view, the invention con- `sists in the construction, arrangement and combination of the various parts` of the device whereby the objects contemplated are attained, as `hereinafter set forth, pointed out in the appended claims and illustrated in the accompanying drawings. i

In the drawings:

Figure 1 is a fragmentary cross-sectional` view of a molded concrete core to which the prestressing wire has been` applied and connected to the lug means and wherein the protective coating is also shown.

Figure 2 is a plan view of the anchoring device connected to a prestressing wire prior to the application of the coating.

Figure 3 is a transverse sectional` vie-w taken on the line 3--3 of Figure 2.

Figure 4 is a transverse sectional view showing the locating of a portion of the anchor lug device in a fo for the pouring of the core. p

In an embodiment of the invention chosen for the purpose of illustration there is shown a molded concrete core 10 to which a prestressing wire 11 has been applied and ultimatelycovered with a'plastic coating 12. In this instance the coating is a concrete grout. p

More particularly, the core 10 illustrated and described is one constituting molded concrete throughout which when properly forrnedwithin a metal form 13 may be constructed without either longitudinal or circumferential reinforcement if desired. The core has an inner surface 14 and an outer surface 15. As a matter of interest it may be noted that in making cores of this general description a cylindrical form like the form 13 is customarily placed in a frame and there rotated and preferably vibrated while moist concrete is deposited. During this time, the concrete takes a level which determines the thickness of the wall of the core. The outer surface of the cere is determined by an interior surface 16 of the form 13. The inner surface 14 is determined by oneor another of the usual methods of rolling or screening. x

The anchor lug comprises `a body herein having the form of a somewhat rectangular block indicated generally by the reference character 17. In the chosen form the lug comprehends a plate serving as a bottom 18,

side walls

19 and 20 and end walls `21 and 22 which form Patented May 19, 1959 3 a box. It is significant that the end wall. 22. is materially thicker than the end wall 21. It is also noteworthy that the upper edges of the

sidewalls

19 and 20 throughout their length, as well as the breadth of the end walls is in an arcuate form conforming to the curvature of the outer surface 15 of the core 10.

In the end wall 22 there is formed an open end slot 25 which extends into the end wall to a depth almost, but not quite equal to, the inside heightl of the wall. It is further important that an insideV face 28 is oblique or undercut in a direction such that the outer edge of the wall is thicker than the wall at the bottom. As shown, the side walls and end walls form a pocket 27 which is open.

At the end of the `body opposite from the thick end wall 22 a rod 29 is attached. The rod is an integral portion ofthe body 17 and extends outwardly adjacent the bottom of the end wall 21. The rod as noted extends somewhat obliquely downwardly and inwardly. At some portion of the rod which in the chosen embodiment is the outer end portion there is provided a knob 30 which is disc-like inl its proportions. The oblique relationship of the rod is such that when the anchor lug is embedded in the concrete of the core 10, all portions of the knob will be embedded in the concrete beneath the outer surface 1S;

In order to anchor the lug in proper position when the core is being cast and during hardening of the concrete there are provided

lugs

31 and 32. It is important to note that both of these lugs are on one of the walls, namely, the wall 20. In each of the lugs is a threaded hole 33. Before the concrete of the core has been poured the anchor lug body 17 is secured against the' inner surface 16 of the form 13 by bolts 34 which pass through properly located holes 35 in the form.

Moreover', by having the

lugs

31 and 32 on one side only of the body, the anchor lug may be located as near as is practically possible to a free end 36 of the core. Thus constructed the wire or cable 11 may be wound as near as possible to the end of thev core and hence provide a maximum of tensioning effect upon the exterior of the core. To assist in a proper locating of the endmost turn of the wire 11 an appropriate coring element 37 capable of making a long oblique depression 37 may be employed. The coring element 37 is normally long enough to extend into the slot 25 to be certain of intercommunication between the depression when formed and the interior of the pocket 27 after the mold has been removed.

After the form 13 has been removed subsequent to extraction of the bolts 34, the core will be ready for application of. the wire 11. This is wound in a spiral path upon the exterior surface 15 of the core by suitable machinery which maintains the Wire under high tension. At the initiation of the Winding the wire may be anchored in an anchor lug of the type described. This may be accomplished by sliding a sleeve 40 of special construction 4over the Wire 1.1. When the sleeve has thus been placed upon the wire leaving a short end 41 exposed the sleeve is gripped upon the wire. Sleeves of this kind are provided with a frangible porcelain lining which fractures when the sleeve is gripped at the areas 42 and the frangible material forms a tight connection between the sleeve and the Wire. Hence, when the sleeve holding the wire is positioned Within the pocket 27, the Wire will be firmly anchored.

After the winding has progressed to the opposite end of the core, Which may be the end 36 by employment of appropriate winding and tensioning machinery another sleeve 40 is applied over the wire at a location such that it will fall within the pocket 27 of the anchor lug at that end. While holding the wire under tension the slee-ve is gripped tightly upon the wire forming a iirm grip as has been previously described. The wire 4. may then be cut, leavinga comparable end 41 and while tension is maintained by a grasp upon the wire somewhat remote from the end, the sleeve is slid into the pocket 27 and the wire passed into the slot 25. Once in position when tension is released the tensile hold upon the Wire 11 will draw an endmost projection 43 of the sleeve against the inside face 28 of the end wall 22 and force the sleeve into the bottom of the pocket, aided as shown by the slope of the face 28.

The wire has been anchored securely as a result of the operation described. Thereafter the coating 12 may be applied in some suitable fashion by virtue of which the entire exposed area of the wire 11 will be covered and embedded in the coating. At the same time portions of the coating will fill the pockets 27 and that portion of the depression 37 not occupied by the wire.

It will be clear from the foregoing description that the anchor lug device is one of rugged characteristics, especially in that` the body and bar can be made integral with each other on a production basis before insertion into the mold by attachment to the inside surface as described. Fashioned and mounted as is inherently possible in the device no welding operation is requisite. The device consequently comprises two parts only, namely, the body and its attached bar in one instance, and the sleeve 40 in the second instance. Once the sleeve has been attached to the ends of the wire these two elements act as one and canibe quickly and easily snapped into place by passing the wire through the slot 25. Because of the pull on the wire being arcuately inwardly toward the core no means is necessary to anchor the wire in the core or close the ends of the slot 25. All parts of the joint lie flush with or depressed beneath the outer surface 15 of the core 10. Should for any reason it become necessary to remove tension on the wire 11 the end of the Wire within the attached sleeve can be readily lifted from the pocket when suilcient additional tension is applied to the adjacent portion of the wire. Any such removal must naturally take place before the plaster coating is applied.

The breadth of the slot 2S is not critical and can be wide enough to take wires of several diierent diameters as long as the portions of the sleeve which are of greatest diameter extend far enough outwardly to engage the inside face '28 of the end wall 22, immediately adjacent the slot.

By employing an anchoring'lugy device of the type herein described, it` becomes apparent that the entire body and its attached parts can be anchored in a position which will become flush with the exterior surface of the core once the mold has Ibeen removed. Being well embedded in the core and by reason of having relatively thick walls at that portion of the body subject to greatest tension, the device can be built with an economic use of material. By employing the material in such form an additional thickness is created Where the anchor lug device is attached to the mold thereby to greatly convenience the molding operation.

Furthermore by reason of the simple arrangement described no special attention need be given initially to thelength of the wire until it is completely wound. When this has been accomplished the wire can be cut-off forming a free end and the sleeve 40 can then be slid into proper position and clamped upon the wire. This is done while the wire is still held under tension by a grip upon the wire to the right of the anchor lug device as illustrated in Figures 1 and 2. Cnce the anchor lug has been fastened, the anchor lug with the wire is pressed into the pocket 22 and tension can thereafter be released upon the wire.

From the foregoing description it will be appreciated that the anchor lug device is of extremely simple form and construction and that it provides ample strength and rigidity at the very necessary portions while minimizing the mass of material within those portions which will not takegreat strain. lFurther by coupling theanchoring ability of concrete withthe anchoring ability of the body of the lng device, the strength and ruggedness of the connection is improved and will not be disturbed, especially after the coating 12 has been poured in place.

By reason of the structure and combination of the device being as has been described, should there be a 'variation in the size of the wires or wire cable, no variation need be made in anchoring lug device other than a change in the inside diameter of the sleeve. Hence the anchoring of the wire is accomplished in a very simple, economical and expeditious fashion and the device when used in the manner described will provide an ample `anchoring effect for prestressed wire.

. While I have herein shown and `described my invention in what I have conceived to be the most practical and preferred embodiment, it is recognized that departures may be made therefrom within the scope of my invention, which is not to be limited to the details disclosed herein but is to be accorded the full scope of the claims so as to embrace any and all equivalent devices.

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

l. A cable anchoring lug for embedding in a mass of concrete formed in a mold comprising a bar adapted to engage in the concrete, a block on said bar, means forming a pocket in said block, an end wall for said pocket, said end wall having a cable slot therethrough open at an exposed edge, and attachment means on said block adapted to temporarily receive cooperating attachment means on said mold, and an anchor sleeve or breadth greater than the breadth of the slot receivable in said pocket when attached to a cable whereby the cable is anchored against said end wall.

2. A cable anchoring lug for embedding in a mass of concrete formed in a mold comprising a bar having configurations thereon adapted to engage in the concrete, a block integrally lfastened to said bar, means forming a pocket in said block having end walls and side walls, one of said end walls having a cable slot therethrough open at the exposed edge, and attachment means on `said block adapted to temporarily engage a cooperating attachment means on said mold during pouring and setting of the concrete, and an anchor sleeve of size smaller than said pocket and of breadth greater than the breadth of the slot receivable in said pocket when attached to a cable whereby the cable is anchored therein.

3. A cable anchoring lug for embedding in a mass of concrete formed in a mold comprising a bar having con gurations thereon adapted to engage in the concrete, a plate integrally secured to said bar intermediate the ends, said plate having a relatively thick end wall, a relatively thin end wall at the opposite end, and side walls on said plate intermediate the end Walls forming a pocket, said thick end wall having a cable slot therethrough communicating between the pocket and the exterior and open at an exposed edge, threaded holes in said block adapted to temporarily receive bolts extending through said mold, and an anchor sleeve of size smaller than the pocket and of diameter greater than the breadth of the slot receivable in said pocket when attached to a cable whereby the cable is anchored in the pocket.

4. A cable anchoring lug for embedding in a mass of concrete formed in a mold comprising a bar having configurations thereon adapted to engage in the concrete, a plate integrally secured to said bar, a relatively thick end wall and side walls on said plate forming a pocket, said thick end wall having a cable slot therethrough communicating between the pocket and the exterior and open at an exposed edge, threaded holes in the lug adjacent one of said side walls adapted to temporarily receive bolts extending through said mold, and an anchor sleeve of breadth greater than the breadth of the slot receivable in said pocket when attached to a cable whereby the cable is` anchored therein.

box adjacent opposite ends thereof adapted to tem-` porarily receive bolts extending through the mold, and an anchor sleeve of breadth greater than the breadth of the slot and less than the breadth of the pocket receivable in the pocket when attached to a cable, whereby the cable is anchored therein.

6. A cable anchoring lug yfor embedding in a mass of concrete formed in a mold comprising an elongated box having walls forming an elongated pocket, means forming an open slot in the wall at one end of the box, said last identified wall having an undercut inside face, a bar at the other end of the box extending endwise and obliquely relative to the bottom of the box, transversely extending protrusion means on the bar adapted to engage the concrete whereby to anchor the box against endwise movement, means forming threaded holes on one side of the box adjacent opposite ends thereof adapted to temporarily receive bolts extending through the mold, and an anchor sleeve of breadth greater than the breadth of the slot and less than the breadth of the pocket receivable in the pocket when attached to a cable, whereby the cable is anchored therein.

7. In a prestressed molded concrete pipe having a cable wound therearound under tension, `an anchor connection assembly comprising a section initially embedded in the molded concrete pipe at a predetermined depth beneath the surface, said section including a block, end walls and side walls of said block forming an elongated pocket having an open side substantially flush with said surface, a cable slot through one of said walls and extending inwardly from an exposed edge of said last end wall, a sleeve having a size smaller than the pocket and having a cable aperture therethrough lined with a cable engaging coating and subject to compression into anchoring engagement with the cable, said cable being in a position extending through said cable slot into the pocket and within said sleeve, the portion of said cable in the sleeve and the sleeve having a position in the pocket with one end of the sleeve in abutting relationship with the inside face of said one end wall.

8. In -a prestressed molded concrete pipe having a cable wound therearound under tension, an anchor connection assembly comprising a bar having configuration means thereon initially embedded in the molded concrete pipe at a predetermined depth beneath the surface, a plate integrally secured to said bar, a relatively thin end wall on the plate, a relatively thick end wall on the plate, and side walls on said plate intermediate said end walls, said walls forming an elongated pocket having an open side coincident with the surface of the concrete, means forming a cable slot through said thick wall communicating between the pocket and the exterior and extending inwardly frorn an exposed edge of said thick wall, a sleeve shorter than the pocket having a cable aperture therethrough lined`I with a frangible coating and a series of axially spaced retention sections of the sleeve compressed into engagement with the cable, said cable being in a position extending through said cable slot into the pocket yand said sleeve, the portion of the cable retained in the sleeve having a position in the pocket with one end of the sleeve in abutting relationship with the inside face of said thick end wall whereby the cable is anchored under tension to said anchor connection.

9. A cable anchoring lug for embedding in a mass of concrete formed in a mold comprising a block, means on said block adapted to engage in the concrete whereby to anchorthe blockA against endwise movement, means forming a pocket in said block, an end Wall for said pocket, SaidY end Wall having -a cable slot therethrough open at an exposed edge, and attachment means on said block adapted to temporarilyv receive cooperating attachment means on said mold, and an anchor sleeve of breadth greater than the breadth of the slot receivable in said pocket when attached to a cable whereby the cable is anchored against said end wall.

References Cited in the le of this patentV UNITED STATES PATENTS Erbe Apr. 8, 1952