Abstract:
A tool for forming a high strength reinforcing bar coupling driving self-locking wedge sleeves over each end of a contractible jaw assembly bridging the abutting ends of the bar to be joined. The sleeves are seated in collars engaged by the distal ends of arms driven for closure by a piston-cylinder power unit and a cam on at least one arm. In one form the cam on one arm is engaged by a roller connected by a tension link to the other arm. In another form cams are provided on each arm driven by rollers fixed with respect to each other. The collars include self-releasing collets seating the sleeves. The tool has other uses such as bar shearing or forming.

Description:
This application claims priority from U.S. Provisional Application No. 60/263,860, titled “Reinforcing Bar Connection and Method,” filed Jan. 23, 2001, and from U.S. Provisional Application No. 60/346,712, titled “Reinforcing Bar Toll and Method,” filed Jan. 8, 2002. 

   This invention relates generally as indicated to reinforcing bar tool and, more particularly, to a tool and method for quickly field or shop cutting, forming or coupling reinforcing bar. 
   BACKGROUND OF THE INVENTION 
   In a prior application there has been developed a reinforcing bar splice or coupling which involves driving a low angle self-locking wedge sleeve over each end of a contractabile jaw assembly causing the jaw assembly to close and engage or grip abutting bar ends to form a high strength splice or coupling. The jaw assembly includes teeth which may cold form, engage, and grip the bar ends penetrating the overall diameter of the bar but not the nominal bar diameter or core. In this manner a high strength connection is formed. When correctly assembled, the bar coupling forms a high compressive and tensile strength coupling qualifying as a Type 2 mechanical connection in all United States earthquake zones. The coupling has been developed by ERICO International Corporation of Solon, Ohio, U.S.A., under the trademark LENTON® LOCK™. LENTON® is a registered trademark of ERICO. 
   While forming such a high strength coupling is a relatively easy task in a lab or shop using elaborate power bench equipment such as presses, field forming these high strength couplings is an entirely different matter. Such couplings can be used horizontally or vertically in columns, or even diagonally. The installation may be at considerable height, in very limited space, and in all kinds of weather conditions. There is probably no work environment more confining, complex and difficult than the arduous installation and erection of steel reinforcing for concrete construction. Laboratory or plant equipment simply is not suitable in a field application. There is, accordingly, a need for a tool useful both in the field or shop for forming such high strength connections or couplings. It would also be desirable if the tool had other uses and applications in the steel reinforced concrete contraction industry. 
   SUMMARY OF THE INVENTION 
   It is, accordingly, an object of the inventor to provide a tool which can quickly make high strength couplings in the field as well as in a shop. It is also an object to provide a tool fully field capable of installing multiple reinforcing bar coupling sizes and which may be automated, obtain a mechanical advantage, provide a constant closing force range at the end of the closing stroke, and which may use variable power requirements to adjust the force applied depending on bar size. It is a further object to provide a tool having other uses in reinforced concrete construction such as bar shearing or bending. 
   It is an aspect of the invention to provide a tool for forming a reinforcing bar connection having opposed drivers each adapted to engage a collar seating a tapered sleeve, with the collars and the tapered sleeves positioned over bar ends, the collars being driven axially of the bar ends to force the sleeves over the opposite ends of a jaw assembly positioned on the bar ends to cause the jaw assembly to contract and grip the bar ends. 
   It is another aspect to provide a tool for forming a reinforcing bar splice having a pair of pivoting arms, the distal ends of which engage and drive oppositely facing sleeve seats positioned over aligned bar ends, with power means to drive the seats axially of the bar ends to force the sleeves over the jaw assembly positioned on the bar ends to cause the jaw assembly to contract to grip and splice the bar ends. 
   It is yet another aspect to provide a method of forming a reinforcing bar coupling comprising the step of placing oppositely directed self-locking wedge sleeves over the butting ends of the reinforcing bar to be joined, placing a contractible jaw assembly over the butting ends, seating the sleeves in collars, and then activating a driving tool to force the collars and wedge sleeves toward each other and over the jaw assembly to contract the jaw assembly and form the coupling. 
   It is also an important aspect of this invention to provide a power operated rebar tool having pivoting arms with the distal end of each arm provided with a notch accommodating reinforcing bar, each distal end also including a bearing section on each side of the notch operative to engage and drive rebar tooling when the arms are closed. 
   To the accomplishment of the foregoing and related ends, the invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a side elevation of a tool in accordance with the present invention also showing, schematically, a control circuit; 
       FIG. 2  is a top plan view of the tool of  FIG. 1 ; 
       FIG. 3  is a perspective view of the tool of  FIG. 1 ; 
       FIG. 4  is a side elevation of a modified form of tool in accordance with the invention; 
       FIG. 5  is a perspective view of the tool of  FIG. 4 ; 
       FIG. 6  is a side elevation of the tool of  FIG. 1  with the bar and coupling to be formed in position; 
       FIG. 7  is a similar side elevation with the tool closed engaging and driving the collars and sleeves toward each other to form the coupling; 
       FIG. 8  is an elevation of a collar segment in the plane of its axis and including a self-releasing collet segment; 
       FIG. 9  is a side elevation of the tool driving a bar shearing fixture; 
       FIG. 10  is an end elevation of the tool driving a bar forming or bending fixture; 
       FIG. 11  is a perspective view of a completed LENTON® LOCK™ coupling as formed by the tool of the present invention; 
       FIG. 12  is a similar view with the self-locking wedge collars and one jaw of the jaw assembly removed; and 
       FIG. 13  is a perspective view of another embodiment of a rebar tool. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring initially to  FIGS. 1 through 3 , there is illustrated a tool shown generally at  20  which comprises an upper arm  21  and a lower arm  22  which are coaxially pivoted together at their proximal ends as indicated at  23 . A distal or outer end of each arm is provided with a notch, shown at  25  and  26 , respectively, the notch extending in the plane of movement of the arms which would be the plane of  FIG. 1  or normal to  FIG. 2 . When the tool is utilized to form a coupling, the notches accommodate reinforcing bar passing therethrough. 
   As seen more clearly in  FIG. 3 , the distal end of each arm includes the bearing section on each side of the notch which is operative to engage and drive rebar tooling when the arms are closed. Each bearing section is rounded or curved and for the distal end of the upper arm  21  the bearing sections are shown at  27  and  28 . For the distal end of the lower arm the bearing sections are shown at  29  and  30 . The bearing sections engage the tooling diametrically opposite any bar or rod passing through the notch and the rounded configuration of the bearing sections maintains the desired contact with the tooling being used with the tool. 
   As can be seen in  FIG. 3 , the upper arm  21  includes a proximal clevis or fork  33 , which accommodates the proximal end of the lower arm  22  and enables the arms to be pivoted together by the pin  34 , forming the pivot  23 . 
   Also mounted on the pivot pin  34  is a support bracket shown generally at  36  which provides a pivot support  37  at the rod end piston-cylinder assembly  40 . The bracket  36  has two upstanding arms on each side of the cylinder seen at  41  and  42  with the cylinder pivot being held in place by removable keepers  43  at the upper end of each arm. The bracket  36  fits snugly over and under the proximal end of the upper arm  21  and is thus a rigid extension of that arm. 
   The rod  46  of the piston-cylinder assembly is connected to a clevis  47  which has separated arms  48  and  49  supported by spherical bearings  50  on shaft  51 . Also mounted on the shaft, each with its own spherical bearing are the eyes  53  and  54  of tension links  55  and  56 , respectively, as well as cam roller  58 . The cam roller  58  is in the center of the pivot pin and may be slightly flanged to ride on cam surface  60  on the top of the upper arm  21 . 
   The eyes  62  and  63  at the lower end of the tension links  55  and  56  are supported by spherical bearings on the ends of pivot pin  64  pivotally connecting the tension links to the lower arm  22 . 
   It can now be seen that as the piston-cylinder assembly  40  extends, the roller  58  will ride over the cam  60  causing the arms to pivot about their proximal ends toward each other, closing the tool for a variety of tasks such as forming a rebar coupling, shearing or cutting rebar, or forming or bending rebar. 
   As seen more clearly in  FIG. 1  the upper pivoting arm  21  is provided with a hole  66  which may accommodate a handle which may manually open the arms when the piston-cylinder assembly is retracted. Return springs may also be provided if desired.  FIG. 1  also illustrates schematically a hydraulic circuit for the piston-cylinder assembly  40  which includes a power supply  67  and a pressure regulator  68  supplying fluid pressure to the blind end of the piston-cylinder assembly as indicated at  69 . The pressure regulator may also be controlled from a controller  70 , in turn controlled by a proximity switch  71  positioned in the receiving end of the distal end of the lower arm  22 . The proximity switch is positioned a distance from the diametral bearing surfaces  29  and  30  and is used to sense the size of the reinforcing bar being accommodated by the tool. In this manner the sensor will recognize the reinforcing bar size and through the pressure regulator will automatically adjust the fluid pressure for the size of bar positioned in the tool. 
   As can be seen, the embodiment of  FIG. 1  has coaxially pivoted arms and a single cam  60  which is the upper edge of the upper arm  21 . The cam  60  is selected so that the concluding portion of the closing stroke generates a constant closing force range. This accommodates variations in reinforcing bar diameter, per nominal size, and the tool automatically stops when appropriate closing force is achieved. A sensor may be provided both to notify the operator when the proper coupling connection has been made and to reverse the piston-cylinder assembly. 
   Referring now to  FIGS. 4 and 5  there is illustrated another embodiment of a tool in accordance with the present invention shown generally at  75 . This illustrated embodiment of the tool includes two pivoting arms  76  and  77  proximally pivoted at pins  78  and  79 , respectively, to rod end cylinder bracket  80 . The distal ends of the arms are provided with removable projecting receivers indicated at  83  and  84 , respectively, each having a notch as seen at  85  and  86 . Each receiver also includes the diametrically opposed rounded bearing surfaces seen more clearly in  FIG. 5  at  87  and  88 . 
   The piston-cylinder assembly  90  is joined to the arms through the bracket  80 , and the rod  91  has secured to the end thereof a triangular yoke  92  which supports the apex of two laterally spaced triangular trusses shown generally at  95  and  96 . Each truss includes angularly related compression members  97  and  98  and a tension member  99  connecting pins  100  and  101  at each end through the eyes shown at  102  and  103 , respectively. Positioned between the eyes of the laterally spaced trusses are cam rollers shown generally at  104  and  105 . The eyes of the spaced trusses as well as the cam rollers may be mounted on the respective pins  100  and  101  each with suitable spherical bearings. The cam rollers  104  and  105  engage cams  107  and  108 , respectively, which are removably mounted on the exterior of the pivoting arms  76  and  77 , respectively. 
   With the tool of  FIGS. 4 and 5  the proximal ends of the arms are pivoted offset from each other on each side of the piston-cylinder assembly  90 , and cams on both arms are engaged by respective rollers on the ends of the trusses to translate the linear movement of the power means to closing movement of the arms. A return spring may be provided between the two arms urging the two arms to an open position. In any event as pressure in the piston-cylinder assembly at the blind end moves the rod  91  to the right as seen in  FIGS. 4 and 5 , the two arms pivot toward each other closing the receivers  83  and  84  on the reinforcing bar tooling within the receivers either to form a coupling, cut or shear reinforcing bar, or form it, for example. 
   Referring now to  FIGS. 6 ,  7  and  8  there is an illustration of the tool forming a LENTON® LOCK™ coupling in accordance with the invention. In  FIG. 6  the tool is open and the receiver or distal ends of each of the arms is positioned, respectively, above and below collars  112  and  113  positioned at each end of the splice  114  forming the coupling joining the reinforcing bars  115  and  116  end-to-end. The coupling splice  114  is shown in greater detail in  FIG. 11 and 12  hereinafter described. 
   As seen in  FIG. 8  the collars  112  and  113  may be formed from half-round collar sections  120  each of which includes a tapered opening  122  which in turn supports a self-releasing collet section shown generally at  123 . The collet section is supported in the collar section by a series of sloping surfaces indicated at  124  so that when the pressure of the tool is released, the collet sections will release the self-locking wedge sleeves seen in more detail in  FIG. 11 . The half-round collar sections are provided with slots  125  and  126  on one side and slots  127  and  128  on the other side. These slots are designed to receive keys shown at  129  in  FIGS. 6 and 7  which hold the two halves of the collar together forming the annular seat for the wedge sleeve. 
   As seen in comparing  FIGS. 6 and 7  the piston-cylinder assembly  40  has been extended and the arms have closed with the round bearing surfaces engaging diametrically opposite sides of the collar formed by the half-round sections driving the wedge sleeves toward each other and over the coupling jaw assembly  114 . This causes the jaw assembly to contract to grip the end-to-end bars  115  and  116  forming a Type 2 splice. When the assembly is completed, the tool is removed and the collars  112  and  113  are disassembled and removed for reuse. 
   Referring now to  FIG. 9 , it will be seen that the same tool  20  is being used to operate a bar shear fixture shown generally at  135 . The upper and lower blade assemblies  136  and  137  are connected by two guide rods seen at  138  and  139  each surrounded by a return compression spring  140  and  141 . The shearing blade assemblies are provided with oppositely projecting, relatively short rods indicated at  143  and  144 . The curved bearing areas of the distal ends of the arms engage shoulders  145  and  146  on opposite sides of the rod extension. In this manner the tooling may quickly be driven to a closed or shut position shearing bar  150 . 
     FIG. 10  illustrates a bar bending or forming fixture which includes male tooling element  154  and female element  155  positioned in the receiver ends of the arms of the tool. Like the shear tooling, the male tooling  154  includes a rod extension  156  filling in notch  25  providing shoulders  157  and  158  on each side thereof to be engaged by the bearing areas of the distal end of the upper arm. Similarly, the female tool  155  includes rod extension  160  fitting in the notch  26  with shoulders  161  and  162  on each side for engagement by the bearing areas of the distal end of the lower arm. Using the tooling illustrated, the bar  164  may quickly be bent to the desired configuration. 
   Referring now to  FIGS. 11 and 12  there is illustrated a LENTON® LOCK™ coupling which the tool of the present invention completes. The coupling shown generally at  114  is joining end-to-end axially aligned deformed reinforcing bars  115  and  116 . The bars are, of course, shown broken away so that only the ends gripped by the splice or connection are illustrated. The connection comprises a jaw assembly shown generally at  168  which includes three circumferentially interfitting jaw elements shown at  169 ,  170  and  171 . In  FIG. 12  the jaw element  170  has been removed. The exterior of the jaw elements form oppositely tapering, shallow angle surfaces  172  and  173  on which the tool of the present invention drives the matching taper lock sleeves  174  and  175 . It is noted that the jaw sections have interfitting portions indicated at  176  keeping the jaw elements properly assembled. When the locking sleeves are driven toward each other by the tool of the present invention, the jaw assembly contracts driving the interior teeth  178  on each jaw element into the deformed, or projecting portions of the bar such as the longitudinally projecting ribs  179  or the circumferential ribs  180 , but not the core  181 . 
   The diameter bar at the core represents the nomial diameter of the bar while the overall diameter includes the longitudinal or circumferential ribs. In any event, the tool of the present invention can quickly complete the coupling seen in  FIG. 11 . 
   Referring now to  FIG. 13 , there is illustrated another tool shown generally at  190  for completing the splice or connection of the present invention. Although the tool is shown connecting the bars  115  and  116  vertically oriented, it will be appreciated that the bars and splice may be horizontally or even diagonally oriented. The tool includes generally parallel levers  191  and  192  connected by center link  193  pivoted to the approximate mid-point of such levers as indicated at  194  and  195 . Connecting the outer or right-hand end of the levers  191  and  192  is an adjustable link shown generally at  196  in the form of a piston-cylinder assembly actuator  197 . The rod  198  of the assembly is provided with a clevis  199  pivoted at  200  to the outer end of lever  191 . The cylinder  201  of the assembly  197  is provided with a mounting bracket or clevis  202  pivoted at  203  to the outer end of lever  192 . 
   The opposite end of the lever  191  is provided with a C-shaped termination pivoted at  204  to a C-shaped tubular member  205  having an open side  206 . A wedge driving collar shown generally at  207  is mounted on the lower end of the open tube  205 . The collar is formed of hinged semi-circular halves  208  and  209 . When closed and locked the wedge collar has an interior taper matching that of the self-locking sleeves  174  and  175 . 
   The lower arm  192  is provided with a C-shaped termination  210  pivoted at  211  to open tube  212  supporting wedge collar  213  formed of pivotally connected semi-circular halves  214  and  215 . When the piston-cylinder assembly is extended, the collars are driven toward each other. 
   In any event, with the various tool embodiments of the present invention the splice as illustrated in  FIG. 11  can quickly and easily be made. 
   The tool of the present invention is capable of installing multiple rebar splice sizes and automatically stops when appropriate closing force is achieved. The tool accommodates variations in rebar diameter, per nominal size, by means of a constant closing force range at the concluding portion of the closing stroke and will function with all types and grades of rebar. The tool provides quick installation times for a bar break coupling in but one actuation of the tool. The tool can, however, perform other tasks in the rebar construction industry such as bar shearing or bar forming or bending. 
   Although hydraulic piston-cylinder assemblies and controls are preferred, it will be appreciated that other types of power actuators may be employed. The preferred form of tool seen, for example, in  FIG. 1  provides force multiplication obtained through the combination of the power unit in conjunction with mechanical cam surface and the rotating tension link. Multiplication also can be achieved with the combination of the power unit and mechanical cams with the translating truss assembly of the  FIG. 4  embodiment. 
   The tool is versatile, light weight, and may have a variety of uses in the steel reinforced concrete construction industry. For example, the components of the tool may be made of 4140 steel and the tool is readily portable at a field or construction site. 
   To the accomplishment of the foregoing and related ends, the invention then comprises the features particularly pointed out in the claims, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.