Abstract:
A mold clamping system for exothermic reaction welding adapted to be power-operated by a power device, the combination comprising a first member adapted to support a first mold portion; a second member adapted to support a second mold portion; and a drive mechanism, adapted to be coupled to the power device, coupled to at least one of said first and second members and capable of moving the first and second members between a first position, in which the first and second mold portions are spaced apart, and a second position, in which the first and second mold portions are engaged, upon actuation of the power device in a first and a second direction, respectively.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a non-provisional patent application which is based on U.S. provisional patent application Ser. No. 61/948,898, filed Mar. 6, 2014, the disclosure of which is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to clamping devices and tools for handling the components of a mold used for exothermic welding of metallic parts. More particularly, the invention relates to a mold clamping system for exothermic welding adapted to be power-operated by a power device, such as a drill. 
       BACKGROUND 
       [0003]    Exothermic reaction welding is commonly used for joining stranded metal cables to each other and for joining ground rods to other metal parts. A two-piece mold made of graphite, ceramic or other refractory material contains an internal crucible in which a powdered weld mixture is placed after the mold sections are clamped together. The weld mixture typically consists of copper oxide and aluminum. The bottom of the crucible forms a seat for a metal retainer disc that supports the powdered material. Ignition of the powdered material results in an exothermic reaction in the crucible that liquefies the powder, which then melts the metal disc. The molten metal then is free to flow through a tap hole or passageway into a weld cavity that contains the metal parts to be welded. After the weld is completed the mold sections are separated and removed from the weld site, and are then cleaned and prepared for reuse. 
         [0004]    The mold sections typically are manually moved relative to each other using handle clamps, which have projecting pins that engage bores in the mold sections and bracket-mounted thumbscrews that tighten the clamps in position. Some clamps have pivoted toggle frames that enable the mold sections to close and open through relative pivotal motion. See, for example, U.S. Pat. No. 5,533,662, the disclosure of which is hereby incorporated herein by reference. Other clamps have mold-engaging portions that close and open the mold sections through relative linear motion. See, for example, U.S. Pat. No. 5,660,317, the disclosure of which is hereby incorporated herein by reference. Other devices used to open and close the mold halves in exothermic reaction welding include U.S. Pat. Nos. 5,954,261; 6,382,496; 6,776,386; 6,789,724; and 7,240,717, the disclosures of which are hereby incorporated herein by reference. 
       SUMMARY OF THE INVENTION 
       [0005]    The mold clamping system of the invention is configured to operate using a powered device to close and open the mold sections. The power source may be electric, hydraulic or pneumatic, or any combination of those, or another suitable source. The powered device may be an integral part of the system or detachable therefrom, and preferably is protected from the heat generated during welding. If the powered device is detachable, the system may include a rotatable shaft configured for releasable engagement by the chuck of a conventional electric drill or other power tool. Use of the power-operated mold clamping system can greatly speed joining various stranded metal cables, which is especially beneficial when numerous welds are performed in the field. 
         [0006]    The system may be configured such that one or plural sections of the mold are moved during mold closing and opening. Power transmission to the mold section(s) may be effected through a screw drive, a rack-and-pinion drive, a cable drive, a belt drive, or any other suitable mechanism. The system may have a stationary base and/or a guide, such as a rail or a slide, which controls relative motion of the mold sections. When the mold sections are closed, the system exerts sufficient force on the mold to contain the exothermic reaction. 
         [0007]    The system is provided with pins, clamps, thumbscrews, trays, etc. for attaching it to the mold sections. Any section of the mold optionally may be provided with an adjustable attachment for guiding a conductor or other item into place while the mold is closing or opening. 
         [0008]    In more detail, the invention of this application relates to a mold clamping system for exothermic reaction welding adapted to be power-operated by a power device, the combination comprising a first member adapted to support a first mold portion; a second member adapted to support a second mold portion; and a drive mechanism, adapted to be coupled to the power device, coupled to at least one of the first and second members and capable of moving the first and second members between a first position, in which the first and second mold portions are spaced apart, and a second position, in which the first and second mold portions are engaged, upon actuation of the power device in a first and a second direction, respectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
         [0009]    Preferred embodiments of the disclosed invention are described in detail below, purely by way of example, with reference to the accompanying drawing figures, in which: 
           [0010]      FIG. 1  is a rear elevational view of a first embodiment of the mold clamping system of the invention shown in the mold-closed position; 
           [0011]      FIG. 2  is a right side elevational view thereof; 
           [0012]      FIG. 3  is a rear elevational view thereof shown in the mold-open position; 
           [0013]      FIG. 4  is a rear elevational view thereof similar to  FIG. 1  but shown without its exterior housing; 
           [0014]      FIG. 5  is a front perspective thereof without the housing and in the mold-closed position; 
           [0015]      FIG. 6  is a right side elevational view thereof without the housing; 
           [0016]      FIG. 7  is a bottom plan view thereof without the housing; 
           [0017]      FIG. 8  is a rear elevational view thereof similar to  FIG. 4  but shown in the mold-open position; 
           [0018]      FIG. 9  is a front perspective view similar to  FIG. 5  but shown in the mold-open position; 
           [0019]      FIG. 10  is a front perspective view of a second embodiment of the mold clamping system of the invention shown in the mold-closed position; 
           [0020]      FIG. 11  is a front elevational view thereof; 
           [0021]      FIG. 12  is a right side elevational view thereof; 
           [0022]      FIG. 13  is a front perspective view of portions of the system shown in the mold-closed position; 
           [0023]      FIG. 14  is a front perspective view thereof shown in the mold-open position; 
           [0024]      FIG. 15  is a front elevational view thereof shown in the mold-open position; 
           [0025]      FIG. 16  is a right side elevational view thereof shown in the mold-open position; 
           [0026]      FIG. 17  is a perspective view similar to  FIG. 13  of portions of the system shown in the mold-open position; 
           [0027]      FIG. 18  is a perspective view of a third embodiment of the mold clamping system of the invention taken from the front and the right side thereof and shown in the mold-closed position; 
           [0028]      FIG. 19  is a right side elevational view thereof; 
           [0029]      FIG. 20  is a perspective view thereof taken from the front and the left side with the left half of its housing removed to reveal inner details; 
           [0030]      FIG. 21  is a left side elevational view thereof; and 
           [0031]      FIG. 22  is a front elevational view thereof. 
           [0032]      FIG. 23  is a rear elevational view of a fourth embodiment of the mold clamping system of the invention shown in the mold-closed position; 
           [0033]      FIG. 24  is a right side elevational view thereof; 
           [0034]      FIG. 25  is a rear elevational view thereof shown in the mold-open position; 
           [0035]      FIG. 26  is a rear elevational view thereof similar to  FIG. 23  but shown without its exterior housing; 
           [0036]      FIG. 27  is a front perspective thereof without the housing and in the mold-closed position; 
           [0037]      FIG. 28  is a right side elevational view thereof without the housing; 
           [0038]      FIG. 29  is a bottom plan view thereof without the housing; 
           [0039]      FIG. 30  is a rear elevational view thereof similar to  FIG. 26  but shown in the mold-open position; and 
           [0040]      FIG. 31  is a front perspective view similar to  FIG. 27  but shown in the mold-open position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     FIGS.  1 - 9   
       [0041]    Referring to  FIGS. 1-3 , a first embodiment of the invention includes a scissor-like mechanism  2 , preferably made of steel, high-temperature plastic or other suitable material, which clamps onto two mold sections or portions and pivots them between closed and open positions. Mechanism  2  is disposed outside and supported by a four-sided housing  4 , preferably made of steel, high-temperature plastic or other suitable material, having a front wall  6 , a rear wall  8  parallel to the front wall, and two side walls  10  substantially parallel to each other. Housing  4  has an open top and an open bottom and may be made of steel, high-temperature resistant plastic or other suitable material. The lower, tapered portions of the front and rear walls  6 ,  8  have aligned holes or passageways  12  that receive and support a bolt or pivot axle  14 , which defines the primary pivot axis of the mechanism. Each of the front and rear walls  6 ,  8  also has an arcuate slot  16 , and those slots are aligned and serve as guides for other pivoted parts of the mechanism, as described below. The upper third of each wall  6 ,  8  has a central bulge  18  in which an upper shaft bearing (not shown) is firmly seated. 
         [0042]    Referring to  FIGS. 4-7 , external mechanism  2  comprises first and second clamping assemblies or members  20 ,  30  that overlap at the center of the housing  4 , where they are pivotally attached to one another and to the housing by bolt  14 . Clamping assembly  20  comprises upstanding parallel plates  21  and a depending bracket  22  all welded to a clamping bar  24 . Two mold-engaging pins  26  depend from clamping bar  24 . A thumbscrew  28  threaded into bracket  22  can be tightened against one mold section when the pins are fully inserted therein. Similarly, clamping assembly  30  comprises upstanding parallel plates  31  and a depending bracket  32  all welded to a clamping bar  34 . Two mold-engaging pins  36  depend from clamping bar  34 . A thumbscrew  38  threaded into bracket  32  can be tightened against the other mold section when the pins are fully inserted therein. Ears  27 ,  37  at the respective upper outer corners of plates  21 ,  31  are linked by respective bolts  29 ,  39  to an internal mechanism  40 , disposed in housing  4 , that effects relative pivoting movement of the clamping assemblies  20 ,  30  about bolt  14 . Bolts  29 ,  39  are constrained by slots  16  to move along an arcuate path. 
         [0043]    Internal mechanism  40  comprises a vertical rotatable drive screw  42  rotatable in a lower captive shaft bearing  44 , which is anchored translationally but pivotally to housing  4  via bolt  14 . A torque limiter  46  at the upper end of screw  42  is surrounded by the upper shaft bearing (not shown), which is firmly seated between housing walls  6 ,  8  in central bulges  18 . The drive head  48  of torque limiter  46  is depicted as square; however, any type of drive head (hexagonal, Torx, etc.) would be suitable if compatible with a chuck, socket or other drive of an electric drill or other rotary power source. A traveling threaded nut  50  disposed along drive screw  42  converts rotary motion of the drive screw into linear vertical motion. Two links  52  are pivotally connected to traveling nut  50  and to bolt  29 . Similarly, two links  54  are pivotally connected to traveling nut  50  and to bolt  39 . Links  52 ,  54 , guided by arcuate slots  16 , thus convert the linear motion of traveling nut  50  to pivoting motion of clamping assemblies  20 ,  30  about bolt  14  to close and open the clamped mold sections between first and second positions. Compare  FIGS. 4 and 5  (mold-closed position) to  FIGS. 8 and 9  (mold-open position). To facilitate handling, the drill or other power tool can be releasably attached to housing  4  by a releasable strap  56  or other suitable fastening arrangement coupled to the housing as seen in  FIG. 1 . 
       Second Embodiment 
     FIGS.  10 - 17   
       [0044]    The second embodiment also utilizes two overlapping, pivoted clamping assemblies; however, it has an offset (rather than a central) drive screw, has a single link (instead of four) for controlling relative motion of the clamping assemblies, and is shown without a housing, which is optional. If a housing is incorporated, it may be made of steel, high-temperature resistant plastic or other suitable material. Referring to  FIGS. 10-13 , the first and second clamping assemblies or members  60 ,  70  are pivotally joined to each other by a pin or bolt  58 , which passes through holes in each assembly&#39;s parallel plates  61 ,  71  and acts as a pivot axle. Each assembly also has a clamping bar  64 ,  74 , a bracket  62 ,  72 , a thumbscrew  68 ,  78  and two mold-engaging pins  66 ,  76 . A vertical drive screw  82  is carried by clamping assembly  60  in a frame  84  welded to plates  61 . Frame  84  includes a bottom plate  86  and a top plate  88 , each of which has a clearance hole for drive screw  82 . A traveling internally threaded nut  80 , welded to a bracket  90 , surrounds drive screw  82  and moves between plates  86  and  88  when the drive screw is rotated by a power source connected to its upper end. 
         [0045]    A single link, which includes a threaded rod  92 , adjustably interconnects bracket  90  and plates  71 . One end of rod  92  is rotatably retained in a captive bearing block  94 , which is pivotally attached to bracket  90 . The other end of rod  92  is threaded in a captive bearing  96 , which is pivotally attached by a pin or bolt  98  to ears  77  of plates  71 . The effective length of the link thus can be varied through manual rotation of rod  92  in either direction, which is useful for precisely setting the mold-closed position of the clamping assemblies. An alternate embodiment lacking such adjustment could instead use a single, unthreaded member to pivotally interconnect bracket  90  and ears  77 . 
         [0046]    As can be seen by comparing  FIGS. 10-13  (mold-closed position) to  FIGS. 14-17  (mold-open position), drive screw  82  is constrained by the multi-link geometry to remain in a substantially fixed vertical position relative to first clamping assembly  60 . As drive screw  82  is rotated to open the clamped mold sections, nut  80  travels downward, rotating the second clamping assembly  70  about pin  58  toward frame  84 . Reverse rotation of drive screw  82  moves traveling nut  80  upward, rotating the second clamping assembly away from frame  84  and closing the clamped mold sections. To facilitate handling, the rotary power source can be mounted to first clamping assembly  60  by one or more straps, a bracket or another fastening suitable arrangement (not shown), but similar to strap  56  in  FIG. 1 . 
       Third Embodiment 
     FIGS.  18 - 22   
       [0047]    The third embodiment is designed to open and close two mold sections or portions in linear fashion, rather than pivotally, and is intended for use with a jig (not shown) that typically has a base and an upright post, such as the jig disclosed in U.S. Pat. No. 5,660,317. The jig fixedly supports a lower mold section on or near the base and movably supports an upper mold section above the lower one. 
         [0048]    Referring to  FIGS. 18-22 , a jig-mounted lower pin block  102  having two mold-engaging pins  104  forms the fixed support for the lower mold section. In one arrangement, the lower mold section is internally retained by a ball detent on each pin  104  (not shown) or by an equivalent mechanism. In another arrangement, the lower mold section is retained on pins  104  by brackets and thumbscrews (not shown) carried by pin block  102 , similar to the arrangements of the previous embodiments. A ball detent (not shown) removably retains each pin  104  in a respective hole  106  of pin block  102 . As shown in  FIGS. 18 ,  20  and  22 , holes  106  preferably are formed as an inner pair and an outer pair to enable selective mating of the pins with molds having different hole spacings. 
         [0049]    An upper pin block  112  having two mold-engaging pins  114  forms the movable support for the upper mold section and acts as a traveling nut to open and close the mold sections. In use, the motorized housing  120  from which pins  114  extend would be adjustably secured to the upright post of the jig by a suitably shaped mounting bracket and/or one or more straps, or by another suitable fastening arrangement (not shown). The upper mold section preferably is internally retained by a ball detent on each pin  114  (not shown) or by an equivalent mechanism. A ball detent (not shown) removably retains each pin  114  in a respective hole  116  of pin block  112 . As shown in  FIGS. 18 ,  20  and  22 , holes  116  preferably are formed as an inner pair and an outer pair to enable selective mating of the pins with molds having different hole spacings. 
         [0050]    Referring to  FIGS. 18 ,  20  and  21 , a vertical drive screw  122  in housing  120  is rotatable within a threaded collar  124  retained in upper pin block  112 . The front  121  of housing  120  has two vertical slots  126  through which pins  114  extend and thus define the upper and lower limits of movement of upper pin block  112 . The bottom of the housing has a base plate  128  that serves as a stop for upper pin block  112  and for the bottom end of drive screw  122 . An upper thrust bearing (not shown) keeps the shaft vertical and prevents it from rising during rotation. A handle  129  facilitates manipulation of the unit when not supported on a jig. Housing  120  may be made of steel, high-temperature resistant plastic or other suitable material and optionally may have a heat dissipating front face that shields the housing from the heat of the exothermic reaction within the mold. 
         [0051]    Drive screw  122  is rotated by a gear train  130  driven by an electric motor  132 . Alternatively, motor torque could be applied to the drive screw through a belt and pulley drive, a chain and sprocket drive or any other suitable arrangement. Screw rotation in one direction causes upper pin block  112  to rise and thus open the mold. Screw rotation in the opposite direction causes pin block  112  to descend and thus close the mold. 
       Fourth Embodiment 
     FIGS.  23 - 31   
       [0052]    Referring to  FIGS. 23-26 , a fourth embodiment of the invention includes a mechanism  133 , which is held in place by two blocks  180 ,  182  that pivot with relative movement of the threaded rod or screw  172 . The threaded rod  172  changes angles relative to its position between the closed and open positions. The mechanism is disposed inside of the upstanding parallel plates  151 ,  161  that compose the halves of the clamp and supported by a four-sided housing  134 , preferably made of steel, having a front wall  136 , a rear wall  138  parallel to the front wall, and two side walls  140  substantially parallel to each other. Housing  134  has an open top and an open bottom and may be made of steel, high-temperature plastic resistant or other suitable material. The lower, tapered portions of the front and rear walls  136 ,  138  have aligned holes  142  that receive and support a bolt of pivot axle  144 , which defines the primary pivot axis of the mechanism. Each of the front and rear walls  136 ,  138  also has an arcuate slot  146 , and those slots are aligned and serve as guides for other pivoted parts of the mechanism, as described below. 
         [0053]    Referring to  FIGS. 26-29 ), internal mechanism  133  comprises first and second clamping assemblies or members  150 ,  160  that overlap at the center of the housing  134 , where they are pivotally attached to one another and to the housing by bolt or pivot axle  144 , or rivet or other suitable method of fastening. Clamping assembly  150  comprises upstanding parallel plates  151  and a depending bracket  152  all welded to a clamping bar  154 . Two mold-engaging pins  156  depend from clamping bar  154 . A thumbscrew  158  threaded into bracket  152  can be tightened against one mold section when the pins are fully inserted therein. Similarly, clamping assembly  160  comprises upstanding parallel plates  161  and depending bracket  162  all welded to a clamping bar  164 . Two mold-engaging pins  166  depend from clamping bar  164 . A thumbscrew  168  threaded into bracket  162  can be tightened against the other mold section when the pins are fully inserted therein. Ears  157 ,  167  at the respective upper outer corners of plates  151 ,  161  are linked by respective bolts  159 ,  169  to an internal mechanism  170 , disposed in housing  134 , that effects relative pivoting movement of the clamping assemblies  150 ,  160  about bolt  144 . Bolts  159 ,  169  are received in and constrained by slots  146  to move along an arcuate path. 
         [0054]    Internal mechanism  170  comprises a drive screw  172  rotatable in threaded block or traveling nut  180  which acts against a captive shaft bearing  174  which is translationally but pivotally anchored via bolt  169  and has a pin stop  183  thereon. A torque limiter (not shown) is located at the upper end of screw  172 . The drive head  173  of drive screw  172  is depicted as square; however, any type of drive head (hexagonal, Torx, etc.) would be suitable if compatible with a chuck, socket or other drive of an electric drill or other rotary power source. Threaded block  180  acts as a traveling nut disposed along drive screw  172  and converts rotary motion of the drive screw into pivotal motion of clamp members  150  and  160 . Block  180  is pivotally connected to ear holes via bolt  159 ; through block  182  having a captive shaft bearing  174  therein is pivotally connected to ear holes via bolt  169  and acts as a captive bearing for the end of screw  172 . The linear motion of block  180  on drive screw  172  causes pivoting motion of the clamping assemblies  150 ,  160  about bolt  144  to close and open the clamp mold sections. Compare  FIGS. 26 and 27  (mold-closed position) to  FIGS. 30 and 31  (mold-open position). To facilitate handling, the drill or other power tool can be attached to housing  134  by a strap or other suitable fastening arrangement. 
         [0055]    While exemplary embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes, modifications, additions, and substitutions are possible, without departing from the scope and spirit of the invention and the appended patent claims.