Patent Application
20090263185
1. Field of the Invention
The present invention relates generally to a splice sleeve for reinforcing bars utilized in concrete wall, beam, floor slab structures or columns and, more particularly, to a splice sleeve having a longitudinally elongated shell of lesser length which allows for more reliable, easier and faster installation.
2. Description of the Prior Art
Various devices for splicing sections of reinforcing bar (i.e., “rebar”) are known. More specifically, various grouted splice sleeves for joining a pair of opposed rebar ends are known. For example, my U.S. Pat. No. 4,627,212, the disclosure of which is expressly incorporated by reference herein as if fully set forth, discloses a splice sleeve in which both ends of the interior surface of the sleeve are provided with annular ridges. The annular space between the interior of the sleeve and the exterior of the reinforcing bars is filled with grouting with the ribs on the bars and the ridges on the sleeve interlocking the bars within the sleeve for fixedly connecting and generally aligning the ends of the reinforcing bars. In one embodiment, the splice sleeve has a cylindrical surface over at least one-half of its length with one end portion of the sleeve having either a gradually tapering internal and external surface or a cylindrical surface terminating in a relatively short frusto-conical portion with inwardly tapering internal and external surfaces. The rebar that is used in the splice sleeve has a cylindrical, i.e., non-headed end.
To enhance the strength of the rebar splice, U.S. Pat. No. 6,192,647 to Dahl discloses a grouted pipe coupler in which the rebar ends include an enlarged head 6. The interior of the Dahl device has a uniform diameter.
To provide an even stronger rebar coupling, however, it is desirable to provide a sleeve having an elongated interior section for one of the rebars. By seating a rebar having an enlarged end in the mouth of one end of a tapered sleeve end, it is possible to provide the elongated interior for the opposite bar end.
The present invention is directed to a splice sleeve or coupler and method for coupling a pair of reinforcing bar (“rebar”) ends, or the like. The splice sleeve or coupler includes a tubular sleeve with two side ports, a steeply tapered portion opening at one end which makes up a minor extent of the tubular sleeve and a cylindrical portion with spaced internal ribs opening at the opposite end which makes up a major extent of the tubular sleeve. The opening at the cylindrical end of the sleeve is thus larger than the smaller opening at the tapered end, which latter opening is sized to be only slightly larger than the diameter of the rebar to allow tolerance in the installation procedure.
A first rebar has its end deformed into an enlarged diameter end or head that is captively received into the sleeve's minor extent, tapered end when the first rebar extends out through the sleeve's smaller opening. A second rebar end without an enlarged head is inserted into the sleeve's cylindrical major portion and positioned adjacent the enlarged head of the first rebar. The sleeve is then filled with a high strength grout or other cementious type material to hold the bar ends coupled together. This arrangement allows the rebar end with the enlarged head to be captured or locked in the complementary tapered end with only minor extension into the interior of the sleeve. And, the rebar end without the enlarged head can then occupy a longer or major extent of the sleeve length for better securement with the grout and sleeve interior. In a preferred embodiment, the opening in the side port adjacent the steeply tapered opening is smaller than the opening in the side port adjacent the opposed cylindrical opening to assist in grout filling.
The method for coupling a pair or rebar ends in accordance with the present invention includes the following steps:
(1) Provide a spliced sleeve having a configuration as described in the preceding paragraph;
(2) Form an enlarged head or end on a first rebar and insert the other end of the headed rebar all the way into the sleeve through the cylindrical opening so that the enlarged head sits snugly into the steeply tapered opening at one end of the sleeve;
(3) Insert an end of the second rebar which end has no enlarged head into the cylindrical major extent of the tubular sleeve until it is positioned adjacent the enlarged end of the first rebar;
(4) Pump high strength grout or other cementious material into the side port adjacent the cylindrical opening while closing off the cylindrical opening until the high strength grout fills the interior of the sleeve surrounding the rebar ends as indicated by grout exiting the smaller side port adjacent the tapered opening; and
(5) Allow the high strength grout or other cementious material to cure with the adjacent rebar ends fixedly secured in the splice sleeve.
Accordingly, it is an object of the present invention to provide a splice sleeve and method for connecting the ends of generally aligned reinforcing bars with the sleeve having a generally cylindrical external surface with a shorter length for use in concrete beams, floor slabs, walls and in columns.
Another object of the present invention is to provide a splice sleeve having a generally cylindrical interior surface with one end that terminates in a minor, or relatively short frusto-conical, or tapered, portion with an inwardly tapering surface, and the other end with a major, or relatively long, cylindrical portion.
Still another object of the present invention is to provide a splice sleeve configured to seat a rebar having an enlarged head or end in the complementary frusto-conical minor portion of the sleeve so as to provide an elongated cylindrical major portion for the other bar end.
A still further another object of the present invention is to provide a splice sleeve for reinforcing bars in accordance with the preceding objects in which the splice sleeve is provided with ports adjacent the ends thereof with one port being smaller than the other to enable the interior of the shell to be filled completely with high strength grout or other cementious material so that the entire annular space between the exterior of the reinforcing bar ends and the interior of the shell will be filled with grouting.
A further object of the present invention is to provide a splice sleeve in accordance with the preceding objects in which the internal surface of the cylindrical major portion has annular ridges spaced along its length to cooperate with the ribs on the reinforcing bars and grouting filling the space between the reinforcing bars and the internal surface of the shell to rigidly secure the reinforcing bars, grouting and shell into a fixedly interconnected unit.
Yet a further object of the present invention is to provide a splice sleeve in accordance with the preceding objects which is effective for connecting the ends of reinforcing bars.
Yet still another object of this invention to be specifically enumerated herein is to provide a splice sleeve in accordance with the preceding objects that will conform to conventional forms of manufacture, be of relatively simple construction and easy to use so as to provide a device that will be more reliable, economically feasible, long lasting, durable in service, relatively trouble free in operation, and a general improvement in the art.
These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like reference numbers refer to like parts throughout. The accompanying drawings are intended to illustrate the invention, but are not necessarily to scale.
Although preferred embodiments of the invention are explained in detail, it is to be understood that other embodiments are possible. Accordingly, it is not intended that the invention is to be limited in its scope to the details of constructions, and arrangement of components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the preferred embodiments, specific terminology will be resorted to for the sake of clarity. It is to be understood that each specific term includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. Where possible, components of the drawings that are alike are identified by the same reference numbers.
Referring now specifically to the drawings, the splice sleeve of the present invention illustrated in
The splice sleeve 10 includes an internal surface 24 which has a generally cylindrical portion 32 over a major extent of the sleeve, starting with the cylindrical opening 18 at end 16. The generally cylindrical portion 32 is preferably between about 75% and about 90% of the sleeve length, depending upon the diameter of the reinforcing bars to be spliced. At the other end 17, the internal surface 24 includes a steeply wedged portion 50 which inwardly tapers over a minor extent of the sleeve length, and forms into the smaller circular opening 19. The steeply wedged portion 50 extends preferably only about 10% to about 25% of the sleeve length, depending upon the diameter of the reinforcing bars to be spliced. Preferably, the opening 19 is sized to be slightly larger than the diameter of the rebar to assist in allowing the unheaded portion of the headed reinforcing bar to pull through and lock its headed end in the sleeve.
As illustrated, the internal surface 32 of the cylindrical major portion of the shell 12 includes a plurality of substantially equally spaced annular ridges 30 which preferably are all of equal height or radial dimension from the internal surface 32. Thus, by steeply tapering inwardly portion 50 of the internal surface 24, there is provided a tapered or frustoconical end portion over a minor extent of the sleeve with a cylindrical portion over a major extent of the sleeve.
The internal tapered surface 50 of the shell 12 is complementarily configured to wedgingly and captively receive the headed end 60 of rebar 21. There are many known ways to cold forge a rebar end to form an enlarged head, such as headed end 60 of rebar 21. For example, one such method is disclosed in U.S. Pat. No. 5,709,121, in which a steel reinforcing bar end is hydraulically forged to form the head.
The sleeve 10 includes a pair of grouting ports 27 and 28 which are defined by short projecting bosses 29 on the exterior of the shell 12, with each port adjacent respective ends 16 and 17 of the sleeve. The opening in port 27, adjacent end 16 is larger than the opening 33 of port 28 adjacent end 17, which latter port 28 has a portion closed off by extensions 34.
With rebar 21 having enlarged head 60 formed thereon, the rebar ends are ready to be spliced in the sleeve 10. Rebar 21 is inserted first with the end opposite the headed end 60 inserted through opening 18 until the headed end 16 is wedgedly seated and fitted in the complementary tapered surface 50 with the rebar shaft extending outwardly from end surface 17, as shown in FIG. 1. The headed end 60 of rebar 21 thus occupies only a minor portion, i.e., about 10% to about 25%, of the sleeve length. One end of rebar 20, which has no headed end, is then inserted into the sleeve 10 through opening 18 until the inner ends of rebars 20 and 21 are adjacent in close proximity to each other. Thus the end of rebar 21 occupies a major portion of the length of sleeve 10, approximately about 75% to 90%. The annular space between the internal surface of the sleeve 10 and the portions of the reinforcing bars 20 and 21 in the sleeve between ends 16 and 17 is then completely filled with a flowable and subsequently hardenable material 26, such as for example high strength grout.
In a preferred embodiment, the grout is inserted under pressure into the annular space through the opening of port 27 while the opening 18 is closed off around the shaft of rebar 20. The grout is pumped into port 27 until grout, through restricted discharge, exits the smaller opening 33 of port 28, which indicates that all open space inside the sleeve and around the rebar ends, including the headed end 60 of rebar 21, has been completely filled. The wedging shape of enlarged head 60 in cooperation with the steeply inclined surface 50, and the smaller size of opening 19, serve to close off the opening 19 during insertion of the grout into the interior of the sleeve 10. Once filled, the hardenable material or grout 26 inside shell 12 is permitted to cure.
The tapering of the complementary internal surface 50 which produces a wedging or compression action on the headed end 60 of rebar 21 together with the annular ridges 30 over the cylindrical major portion inside the sleeve 10 and the ribs 22 on the extra length of reinforcing bar extending into the sleeve provide a very secure and rigid bond and interaction between the grout 26, the reinforcing bars 20 and 21, and the cylindrical shell 12 of the spliced sleeve 10.
By using a cylindrical internal surface over a major portion of sleeve length and a tapering internal surface 50 over a minor portion, a splice sleeve of less overall length can be used to effectively connect the reinforcing bars. The splice sleeve can thus be constructed with less total length and steel quantity thereby enabling economic benefits while providing increased strength and reliability as compared with prior art splice sleeves, such as disclosed in my prior U.S. Pat. No. 4,627,212.
When the high strength grout is inserted after the reinforcing bars have been positioned in the sleeve, the grout expands and hardens into intimate contact with the ridges or grooves 22 formed on the exterior of the reinforcing bars and the ridges or grooves 30 formed on the inner cylindrical surface 32 of the sleeve. This action creates a positive locking engagement between the splice sleeve 10, the grout 26 and reinforcing bars 20 and 21. Forces exerted on the reinforcing bars to move them longitudinally outwardly after the grouting has hardened is more effectively resisted due to the wedge shaped action of the inwardly tapering internal surface 50. This provides a wedging or locking action with respect to the grout and this construction provides a positive wedge-like retainment of the grout encased ends of the reinforcing bars in the splice sleeve.
Furthermore, by virtue of engaging the headed end 60 with the internal tapered end 50, an even more secure engagement is made. By virtue of the using the internal tapered surface 50 in conjunction with the headed end 60, the longitudinal space that is required for one of the rebars in a conventional sleeve is reduced. This means that the savings in longitudinal space associated with housing rebar 21 can be devoted to housing the other coupled rebar 20. This configuration therefore provides additional longitudinal space for securing rebar 20. Accordingly, the strength of the coupling can be enhanced.
Referring now to
As explained above, an important feature of the splice sleeve of the present invention is to splice together opposed ends of reinforcing bars, or rebar sections, one of which ends includes an enlarged diameter head or end and the other of which has a conventional end. As such, it will be appreciated by those skilled in the art that when assembling a series of rebar ends using the splice sleeve of the present invention, each reinforcing bar or rebar section is the same with one end including the enlarged head and the other end remaining untreated or conventional.
The interconnection of a series of rebar sections by the splice sleeve of the present invention is illustrated in
The assembly of the next rebar section 106 follows the same procedure described above. More specifically, the non-enlarged end 106b of rebar 106 must be fitted into the third splice sleeve 10c before the untreated end 106b is grouted in place adjacent enlarged head 104a in the second splice sleeve 10b. Such is the same for the next assembly of rebar section 108 in splice sleeve 10c, and so on, until all of the rebar sections have been spliced together.
It is not intended that the present invention be limited to the specific device described herein. The foregoing is considered as illustrative only of the principles of the invention. For example, although the headed end of the rebar has been described as being formed by cold forging, other methods of providing the headed end may be possible as long as they provide a headed end that fulfills the service requirements of the present invention.
Further, numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and, accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
