Patent Publication Number: US-2007095013-A1

Title: Reinforcing bar coupling

Description:
BACKGROUND OF THE INVENTION  
      1. Field Of The Invention  
      The invention is related to the field of devices and methods for coupling reinforcing bars.  
      2. Description Of The Related Art  
      In steel reinforced concrete construction, there are generally three types of splices or connections; namely lap splices; mechanical splices; and welding. Probably the most common is the lap splice where two bar ends are lapped side-by-side and wire tied together. The bar ends are of course axially offset which creates design problems, and eccentric loading whether compressive or tensile from bar-to-bar. Welding is suitable for some bar steels but not for others and the heat may actually weaken some bars. Done correctly, it requires great skill and is expensive Mechanical splices normally require a bar end preparation or treatment such as threading, upsetting or both. They also may require careful torquing.  
      Improvements are continually being sought in mechanical splices and splicing methods, for instance to improve performance, cost, and/or ease of installation.  
     SUMMARY OF THE INVENTION  
      According to an aspect of the invention, a reinforcing bar splice for joining reinforcing bars, includes: a sleeve segment having longitudinal integral ribs deforming to conform to deformations on the reinforcing bars when the sleeve segment and the bars are relatively pressed together; and a clamp operatively configured to relatively press the sleeve segment and the bars together.  
      According to another aspect of the invention, a splice for deformed reinforcing bar includes a sleeve segment having longitudinal ribs on an inner surface; and means to clamp the sleeve segment against an end of the deformed bar to cause the ribs to deform to conform to and lock the deformed bar.  
      According to yet another aspect of the invention, a splice for deformed reinforcing bar includes: a sleeve segment having a deformable interior section weaker than the balance of the segment; and means to press the weaker interior section against the bar to cause it to conform to and lock with the deformed bar.  
      According to still another aspect of the invention, a method of splicing reinforcing bars having deformations thereupon, includes the steps of: placing longitudinal ribs of a sleeve section against ends of the bars; and pressing the longitudinal ribs onto the bars, causing them to conform to the bar deformations.  
      To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
      In the annexed drawings, which are not necessarily to scale:  
       FIG. 1  is an oblique view of a splice of the present invention;  
       FIG. 2  is an exploded view of some parts of the splice of  FIG. 1 ;  
       FIG. 3  is an enlarged cutaway side view partly in section, of part of the splice of  FIG. 1 , illustrating the locking between ribs and a reinforcing bar;  
       FIG. 4  is an end view showing a sleeve section of the splice of  FIG. 1 , with undeformed ribs;  
       FIG. 5  is an end view showing a sleeve section of the splice of  FIG. 1 , with partially-deformed ribs;  
       FIG. 6  is an end view showing a sleeve section of the splice of  FIG. 1 , with fully-deformed ribs;  
       FIG. 7  is an oblique view of a sleeve section according to one embodiment of the present invention;  
       FIG. 8  is an enlarged end view of the sleeve section of  FIG. 7 ;  
       FIG. 9  is a side view of the sleeve section of  FIG. 7 ;  
       FIG. 10  is a view of the sleeve section seen from the bottom of  FIG. 9 ;  
       FIG. 11  is an oblique view illustrating sleeve sections of  FIG. 7  as part of a splice;  
       FIG. 12  is an oblique view of another embodiment of a splice in accordance with the present invention;  
       FIG. 13  is an end view of the splice of  FIG. 12 ;  
       FIG. 14  is a cutaway side view of the splice of  FIG. 12 ;  
       FIG. 15  is an exploded view illustrating details of some of the parts of the splice of  FIG. 12 ;  
       FIG. 16  is an end view illustrating one variation of the splice of  FIGS. 12-15 ;  
       FIG. 17  is an end view illustrating another variation of the splice of  FIGS. 12-15 ;  
       FIG. 18  is an oblique view of an embodiment of a sleeve of the present invention, having an integral sleeve segment with integral longitudinal ribs;  
       FIG. 19  is an end view of the sleeve of  FIG. 18 ;  
       FIG. 20  is an oblique view of yet another embodiment of a splice in accordance with the present invention:  
       FIG. 21  is an end view of the splice of  FIG. 20 ;  
       FIG. 22  is a cutaway side view of the splice of  FIG. 20 ;  
       FIG. 23  is an oblique view of still another embodiment of a splice in accordance with the present invention;  
       FIG. 24  is a cutaway side view of the splice of  FIG. 23 ;  
       FIG. 25  is an end view of the splice of  FIG. 23 ;  
       FIG. 26  is a side view of a further embodiment of a splice in accordance with the present invention;  
       FIG. 27  is an oblique view of a sleeve segment for use in the splice of  FIG. 26 ;  
       FIG. 28  is an end view of the sleeve segment of  FIG. 27 ;  
       FIG. 29  is a side view if the splice of  FIG. 26 , showing the splice prior to engagement of the fingers of the sleeve portions;  
       FIG. 30  is an oblique view of a still further embodiment of a splice in accordance with the present invention; and  
       FIG. 31  is an end view of a sleeve that is part of the splice of  FIG. 30 .  
    
    
     DETAILED DESCRIPTION  
      A reinforcing bar coupling includes a sleeve segment having a deformable interior section weaker than the balance of the segment. The deformable interior section, for example including deformable ribs, is configured to be pressed onto ends of reinforcing bars to be spliced together. The ribs deform onto and around deformations on exterior surfaces on the ends of the reinforcing bars. Thus secured to the ends of the reinforcing bars under pressure, the sleeve segment secures the ends of the reinforcing bars together. The sleeve segment may take any of a variety of forms, such as an insert placed inside a sleeve, or a portion of a sleeve, between the sleeve or portion, and the reinforcing bar. The clamp used to press the sleeve segment onto the reinforcing bar ends may also have a variety of forms, such as bolts contacting the reinforcing bar ends or an insert, bolts arranged to squeeze ends of a sleeve together, tapered collars that engage outer surfaces of one or more sleeve segment, or fingered collars that press inward against the sleeve segment.  
       FIG. 1  shows the generalized configuration of a reinforcing bar splice  10 , for splicing together reinforcing bars  12  and  14  (also referred to herein as “bar ends”). The splice  10  includes a sleeve segment  16  and a clamp  18 . The term “sleeve segment,” as used herein, refers to at least a portion of a curved sleeve, such as would partially or wholly circumferentially engage and surround a cylindrical object, such as an annulet may engage and surround a column. A sleeve segment, as the term is used herein, may completely circumferentially surround a cylindrical object, such as a reinforcing bar. Alternatively, a sleeve segment may be along only a circumferential portion of the cylindrical object. A sleeve segment has a curved inner surface for engaging the cylindrical object. The outer surface of a sleeve section may also be curved, but does not need to be curved. A sleeve segment may be a separate item, or may be a unitary and integral part of a sleeve that fully circumferentially surrounds the object.  
      The sleeve segment  16  includes a deformable inner section, which for instance, includes a plurality of longitudinal (axial) ribs  24 . The clamp  18 , which may include a sleeve  26 , presses the sleeve segment  16  against the bar ends  12  and  14 . The deformable inner section  20  of the sleeve segment  16  deforms to conform to the shape of the bar ends, and in particular to deformations  32  and  34  on the respective bar ends  12  and  14 .  
      This conforming is illustrated in  FIGS. 2 and 3 , which show deformation of the ribs  24  at various locations  36  along an inner surface  38  of the sleeve segment  16 . The locations  36  correspond to the deformations  32  and  34  in the bar ends  12  and  14 . The ribs  24  may also be somewhat flattened and pressed onto the bar ends  12  and  14  at other locations along the bar ends  12  and  14 , i.e., locations where the bar ends  12  and  14  do not have deformations  32  and  34 .  
      It will be appreciated that by deforming the deformable inner section  20  (and the ribs  24 ) of the sleeve segment  16 , and by maintaining pressure to keep the sleeve segment  16  in contact with the bar ends  12  and  14 , a strong splice may be made between the bar ends  12  and  14 . The ribs  24 , for example, provide great strength and a great deal of resistance to pulling out of the bar ends  12  and  14  from the splice  10 . With the ribs  24  deformed and the sleeve segment  16  pressed against and onto the bar ends  12  and  14  by the clamp  18 , the sleeve segment is locked onto the bar ends  12  and  14 , thereby splicing the bars together.  
      The deformable inner section  20  of the sleeve segment  16  may be made of a material that is softer, more malleable, and/or has a greater ductility than the material of the bar ends  12  and  14 . Examples of suitable materials for the sleeve segments  16  are  1117  steel and  1020  steel. It will be appreciated that other suitable materials may be utilized which have a hardness which is less than the hardness of the reinforcing bar ends  12  and  14 . Standard reinforcing bars have a hardness of about 12-15 HRC (about 210 Brinnell-mm ball).  
      The sleeve segment  16  may have uniform material properties, such as a uniform hardness, malleability, and ductility throughout. Alternatively, it will be appreciated that some portions of the sleeve segment  16  may have different properties than other portions. For example, the deformable inner section  20  may be softer than an outer section  40  of the sleeve segment  16 . This may be accomplished, for instance, by flame treating or otherwise treating the outer sections  40  to increase the hardness of the outer section  40 .  
      The splice  10  shown in  FIG. 1  is only a generalized illustration. As will be described in greater detail below, the sleeve segment  16  and the clamp  18  may have a wide variety of various forms. For example, the sleeve segment  16  may be a separate insert placed within one or more sleeves or collars, placed between the rebar ends  12  and  14  and inner surfaces of the sleeves or collars. Alternatively, the sleeve segment  16  with the ribs  24  or other deformable inner section  20  may itself be a part of a sleeve that surrounds the bar ends  12  and  14 . There may be one sleeve segment  16  or multiple such segments.  
      The clamp  18  may be one or more sleeves or collars that press inward on the sleeve segment  16 . Alternatively or in addition the clamp  18  may include one or more bolts that press against the sleeve segment  16 , the bar ends  12  and  14 , or an additional insert. As a further alternative, the clamp  18  may include deformed sections of the sleeve segment  16  utilizing methods such as crimping to permanently deform entire sections of the sleeve segment  16 , thereby deforming the ribs  24  or other deformable inner section  20  of the sleeve  16 , and maintaining pressure of the sleeve section  16  after the crimping operation is completed.  
       FIG. 4  shows details of one embodiment of the ribs  24 . As shown, the ribs  24  have a crenellated shape, although it will be appreciated that the ribs  24  may have a different shape. The ribs  24  each have distal top portions  44 , farther from a sleeve segment body  46  than proximate bottom portions  48  of the ribs  24 . There are troughs  50  between adjacent of the ribs  24 . The top portion  44  of a rib  24  has radiused corners  52  and  54 . Similarly, the bottom portion  48  has radiused corners  56  and  58  where the rib  24  joins to the sleeve segment body  46 , on either side of the rib  24 . The radiused corners  52 ,  54 ,  56  and  58  may prevent or inhibit cracking of the ribs  24 , such as by reducing stress concentration points or stress risers in the ribs  24 .  
       FIGS. 5 and 6  show examples of deformation of the ribs  24  when the sleeve segment  16  is pressed onto the bar ends  12  and  14  by the clamp  18 .  FIG. 5  shows a relatively modest level of deformation, such as may occur in an area corresponding to an area of one of the bars  12  and  14  that does not include deformations  32  and  34 . In the configuration shown in  FIG. 5  the top portions  44  of the ribs  24  are somewhat flattened, reducing the distance between adjacent of the top portions  44  in the troughs  50 . The spacing in the troughs  50  between the bottom portions  48  of adjacent of the ribs  24  may be substantially unchanged by the deforming process, or alternatively may be reduced somewhat, but by less than the spacing reduction between the top portions  44 .  
       FIG. 6  illustrates a more pronounced deformation of the ribs  24 . The configuration shown in  FIG. 6  may occur in an area of the inner surface of the sleeve segment  16  corresponding to the deformations  32  and  34 . The top portions  44  of the ribs  24  are sufficiently flattened so as to substantially close off the tops of the troughs  50 . The top portions  44  may thereby come into contact with one another. Again, as with the configuration shown in  FIG. 5 , the distance between the bottom portions  48  of the ribs  24  may be substantially unchanged, or may be reduced somewhat without causing contact between the bottom portions  48  of adjacent of the ribs  24 .  
      What follows now are descriptions of various particular embodiments of the splice  10 . These various illustrative embodiments provide some idea of the great range of configurations that may utilize the deformable longitudinal (axial) ribs  24  or other deformable inner section  20 .  
       FIGS. 7-10  illustrate a sleeve section  116  that has a sleeve section body  118  having tapered outer surfaces  120  and  122 . The sleeve section wall or body  118  has notches  126 ,  128 , and  130  therein. Troughs  132  between adjacent of the ribs  124  provide thinned hinged points  136 ,  138 , and  140 , at which elements or sections  142 ,  144 ,  146 , and  148 , can pivot relative to one another. It should be noted that a trough  132  between adjacent of the ribs  124  does not necessarily correspond in location to each of the notches  126 ,  128 , and  130 .  
      The taper of the tapered outer surfaces  120  and  122  may be between about 1 and about 5 degrees. The sleeve segments  116  may have an overall extent of about 125 to about 150 degrees.  
      With reference now in addition to  FIG. 11 , a clamp  168  is used to clamp the sleeve section  116  and an additional sleeve section  176  to reinforcing bar ends  182  and  184 , to form a splice  185 . The clamp  168  includes a pair of tapered collars  186  and  188 . The tapered collars  186  and  188  have tapered inner surfaces, such as the inner surface  190  of the collar  186 . The tapered inner surfaces correspond to and interact with the tapered outer surfaces  120  and  122  of the sleeve sections  116  and  176 . The tapered collars  186  and  188  may be driven onto the sleeve sections  116  and  176  with an appropriate tool. Axial force from the collars  186  and  188  result in a radial inward force on the sleeve sections  116  and  176 , driving the sleeve sections  116  and  176  toward and onto the reinforcing bar ends  182  and  184 . This may deform the ribs  124 , especially conforming them to deformations on the reinforcing bar ends  182  and  184 . Further details regarding suitable collars and tools may be found in U.S. application Ser. No. 10/155,551, filed Jan. 23, 2002; in U.S. application Ser. No. 10/055,399, filed Jan. 23, 2002; and in a concurrently-filed application, Attorney Docket No. ERICP0326USB, titled “Reinforcing Bar Connection and Method.” All of these applications are hereby incorporated by reference in their entirety.  
      Turning now to  FIGS. 12-14  a splice  210  for coupling together reinforcing bar ends  212  and  214  is shown. The splice  210  includes a clamp  218  for clamping a pair of sleeve segments  220  and  222  into and/or onto the bar ends  212  and  214 . The clamp  218  includes a sleeve  226  into which the sleeve segments  220  and  222  are inserted. The sleeve  226  has a plurality of radially-oriented protrusions  230 , each of which has a threaded hole therein for receiving one of a plurality of bolts or jack screws  232 . The bolts  232  may be shear bolts, which have heads that shear off when a certain level of torque is reached. The bolts  232  press down onto the upper sleeve segment  220 , pressing the upper sleeve segment  220  into or onto the bar ends  212  and  214 , and pressing the bar ends  212  and  214  into or onto the lower sleeve segment  222 . The use of shear bolts as the bolts  232  controls the amount of force that is used in pressing the sleeve segments  220  and  222  onto the bar ends  212  and  214 . In addition, the use of shear bolts as the bolts  232  reduces the level by which the bolts  232  protrude from the protrusions  230  of the sleeve  226 , after installation is complete.  
      As best shown in  FIG. 13 , the lower sleeve segment  222  may have a greater circumferential extent than the upper sleeve segment  220 . However, it will be appreciated that alternatively the sleeve segments  220  and  222  may have substantially identical circumferential extent, or that the upper sleeve segment  220  may have a greater circumferential extent than the lower sleeve segment  222 .  
      With reference now to  FIG. 15  the lower sleeve segment  222  has longitudinal ribs  234  thereupon. The ribs  234  are designed to be deformed when pressed onto the bar ends  212  and  214 , in a manner similar to that described with regard to other embodiments. The upper sleeve segment  220  has circumferential teeth  238  thereupon. The teeth  238  are designed to bite into the bar ends  212  and  214 , thus securing the tops of the bar ends  212  and  214 .  
      In addition, the lower sleeve segment  222  may have axial teeth  240  on an outer surface  242  thereof. The axial teeth  240  may bite into a bottom part of the sleeve  226 , thus preventing sliding of the lower sleeve segment  222  relative to the sleeve  226 . The outer surface axial teeth  240  of the lower sleeve segment  222 , and the inner surface axial teeth  238  of the upper sleeve segment  220 , will in general be harder than the portions of the splice  210  which they contact. That is, the axial teeth  238  of the upper sleeve segment  220  will in general be harder than the material of the bar ends  212  and  214 . The outer axial teeth  240  of the lower sleeve segment  222  may be harder than the bottom portion of the sleeve  226 . This facilitates biting of the axial teeth  238  and  240  in the respective surfaces that they contact.  
      Many variations are possible regarding the securement of the upper sleeve segment  220  to the bar ends  212  and  214 , and the securement of the lower sleeve segment  222  to the sleeve  226 . For either or both securements, it will be appreciated that the axial teeth shown may be omitted.  
      Other variations are illustrated in  FIGS. 16 and 17 . Referring to  FIG. 16 , according to one variation, an upper sleeve segment  250  has longitudinal (axial) ribs thereupon, and a lower sleeve segment  256  has axial teeth on an inner surface thereof. In another variation, illustrated in  FIG. 17 , both an upper sleeve segment  260  and a lower sleeve segment  262  may have respective sets of longitudinal ribs thereupon.  
      It will further be appreciated that it may be possible to omit the upper sleeve segment  220  entirely, with the bolts  232  directly engaging the bar ends  212  and  214 .  
      As shown in the  FIG. 12 , the bolts  232  are substantially in a single line along the axis of the bar ends  212  and  214 . It will be appreciated that alternatively, the protrusions  230  and the bolts  232  may be other than in a single line, for example, being in a zigzag configuration, perhaps used in conjunction with a wider (larger circumferential extent) upper sleeve segment  220 . Such arrangement may allow for a shorter sleeve  226 , while still providing sufficient force to maintain the bar ends  212  and  214  engaged in the splice  210 .  
      As another alternative, it will be appreciated that three or more sleeve segments may be utilized. Some or all of the sleeve segments may have a longitudinal ribs or other deformable elements for being pressed onto and engaging the bar ends  212  and  214 .  
       FIGS. 18 and 19  show an alternative sleeve  320  that includes, as an integral part, a sleeve segment  322  having ribs  324  formed thereupon. The sleeve  320  includes a protrusion  330  having a number of bolt holes  332  for receiving suitable bolts, such as the shear bolts discussed above. The sleeve  320  may be formed for example by extrusion. It will be appreciated that the sleeve  320  may be incorporated into splice  210  described above, with for example, the sleeve  320  replacing the sleeve  226  and the lower sleeve segment  222 . External parts of the sleeve  320  may be flame treated or otherwise hardened, leaving the longitudinal ribs  324  softer than other parts of the sleeve  320 .  
      Turning now to  FIGS. 20-22 , a splice  410  is illustrated coupling together bar ends  412  and  414 . The splice  410  has a clamp  418  for pressing sleeve segments  420  and  422  onto and/or into the bar ends  412 . The clamp  418  includes a C-shaped sleeve  426 , and bolts  432  that pass through bolt holes  434  in flanges  436  and  438  of the sleeve  426 . The upper flange  436  has smooth holes, and the lower flange  438  has threaded holes. As one of the bolts  432  is screwed into the threads of the holes  434 , the flanges  436  and  438  are subject to an increasing tightening force. This constricts the cylindrical portion of the sleeve  426 , providing a pressing force on the sleeve segments  420  and  422  against the bar ends  412  and  414 . One or both of the sleeve segments  420  and  422  may have deformable longitudinal ribs thereupon, the operation of which has been described above with regard to other embodiments. The sleeve  426  may be made of a variety of suitable materials, such as suitable steels, that have sufficient flexibility for pressing against the sleeve sections  420  and  422 .  
      Turning now to  FIGS. 23-25 , a splice  510  is shown that includes a clamp  518  for pressing sleeve segments  520  and  522  onto and/or into reinforcing bar ends  512  and  514 . The sleeve segments  520  and  522  may be similar to the sleeve segments discussed above. The sleeve  526  includes an upper sleeve half  528  and a lower sleeve half  530 . The upper sleeve half  528  has a pair of rows of through-holes  532  on opposite diametric sides of the bar ends  512  and  514 . The lower sleeve half  530  includes a corresponding array of threaded holes  534 . The holes  532  and  534  are aligned, and are configured to receive a plurality of bolts  536  to securely clamp the sleeve halves  528  and  530  together, thereby pressing the sleeve segments  520  and  522  inward to engage the bar ends  512  and  514 .  
      With reference now to  FIGS. 26-29 , a splice  610  includes a clamp  618  that has a pair of fingered sleeves  620  and  622  that press inward against a ribbed sleeve section  626 . This inward pressing of the sleeve section  626  engages the sleeve section  626  with reinforcing bar ends  612  and  614 . With particular reference to  FIGS. 27 and 28 ; the sleeve segment  626  has multiple hinged section  640 , with outer wall notches  642  between the sections. Along an inner surface of the sleeve segment  626  are a series of longitudinal (axial) deformable ribs  644 .  
      The sleeves  620  and  622  have respective sets of fingers  650  and  652 , as is best shown in  FIG. 29 . The fingers  650  and  652  have angled surfaces. When the sleeves  620  and  622  are slid toward one another from opposite sides of the splice  610 , the fingers  650  and  652  interlace or interdigitate, as shown in  FIG. 26 . The fingers of each of the sleeves slide under the unfingered portion of the other sleeve, and are pressed inward as the sleeves  620  and  622  are pushed together. The inward pressure is transmitted to the sleeve segment  626 , which presses in upon the bar ends  612  and  614 , thereby deforming portions of the longitudinal ribs  644 .  
       FIG. 30  shows the splice  710  that involves cold-swaging or crimping portions of an internally ribbed sleeve  720  to couple together reinforcing bars  712  and  714 . With reference to  FIG. 31 , sleeve  720  has ribs  724  along its internal surface. The cold-swaged or crimped portions, which are indicated in  FIG. 30  by reference number  730 , are portions that are pressed inward by use of a suitable tool, such as a portable hydraulic press with special dies. It will be appreciated that the cold-swaging operation may be accomplished with less tool force than in previous cold-swaged couplers, due to the relatively soft material of the sleeve  720  that is employed. Rather than needing to cold-swage or crimp a hard steel sleeve, the relatively soft steel of the sleeve  720  and in particular the ribs  724 , need only be deformed. It will be appreciated that the configuration and placement of the swaged areas  730  may take any of a wide variety of suitable shapes and configurations.  
      Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.