Patent Publication Number: US-2007102410-A1

Title: Torch hex end structure

Description:
BACKGROUND  
      The invention relates to the art of electric arc welding and more particularly to an improved torch for the gun between a wire feeder and the welding operation.  
     INCORPORATION BY REFERENCE  
      The design of the torch at the welding end of a gun is the subject of many patents that describe the background of the present invention. Some of these patents and/or applications are United Kingdom Application No. 2,285,404; Canadian Application No. 2,106,837; Canadian Application No. 2,139,152; European Application No. 0 590 728 A1; and U.S. Pat. No. 5,313,046. These prior art examples of the torch to which the present invention is directed are incorporated by reference herein as background information and to describe some of the attributes required for a torch of the type to which the invention is directed.  
     BACKGROUND OF THE INVENTION  
      In electric arc welding, a gun is a flexible, elongated element having a rear end connected to a wire feeder and a front end for a welding torch. The gun includes an elongated flexible conduit directing current and shielding gas from the wire feeder to the welding torch. Such a mechanism is employed for hand held welding and for robotic controlled welding in the trade.  
      The torch includes a contact tip through which the welding wire is directed from the wire feeder through the flexible tube to the welding operation. This tip is supported in a conductive cylindrical assembly receiving power from the wire feeder.  
      Shielding gas is directed from a diffuser in the cylindrical assembly into a chamber defined by an outer nozzle through the nozzle into the area around the contact tip so the shielding gas forms a protective layer between the molten metal of the welding operation and atmosphere. All of these requirements of a torch require complex machined components at the end of the torch which substantially increases the cost and adversely affects the operability of the torch during the welding operation. Furthermore, the welding operation itself creates spatter, especially during short circuit conditions so the forward end of the torch including the contact tip and diffuser is subject to substantial deterioration over time caused by spatter together with the tremendous arc temperature involved in the welding operation.  
      Shielding gas is directed into the welding operation from diffuser orifices circumferentially spaced around the torch and directed ultimately to the contact tip at the welding operation. Consequently, torches have diffuser orifices for shielding gas; however, these orifices must be oriented to prevent unwanted cavitation. It has been found that these orifices should be as close as possible to the welding operation. Such closeness drastically increases the tendency for spatter to affect the laminar flow of shielding gas from the diffuser orifices.  
      Robotic assemblies are commonly used with welding guns. Previously, when robotic gun assemblies were dismantled, the down time was extensive because there was no quick and easy means to precisely reassemble the robotic gun. A previous example of a keyed alignment system for a welding torch used with a robotic gun assembly is shown in U.S. Pat. No. 5,451,117 which is hereby incorporated by reference. A mounting arm which provides for various methods of changing position of the welding gun with respect to the robotic arm and the position of the gun with respect to its housing as well as providing easy disassembly of the gun from the robotic arm is described in co-pending application Ser. No. 11/178,819, filed on Jul. 11, 2005, which is also incorporated herein by reference.  
      Furthermore, a welding gun which allows for various positions of the forward end and rear end of the gun is needed without completely disassembly of the gun. Accordingly, it is considered desirable to provide a welding gun which allows various positions of the welding gun with respect to the robotic assembly and with respect to the handle without completely disassembling either the gun or the robotic assembly. The ability to supply anti-spatter liquid and an air purge is also desirable.  
     SUMMARY OF THE INVENTION  
      The present invention is directed to a welding gun. In particular, the invention is directed to a welding gun having a front end housing adjacent a welding torch and a rear end housing adjacent a welding wire feeder.  
      The present invention provides a hexagonally shaped housing and conduit for positioning the gun in several positions with respect to a robotic mounting arm. More particularly, a welding gun assembly is provided for directing a welding wire toward a workpiece, having a torch at a forward portion of the gun; and a welding wire feeder at a rearward portion of the gun. A first housing is positioned adjacent the torch and a second housing is positioned adjacent the wire feeder. The second housing has a first, cylindrical opening and a second, hexagonally shaped opening adjacent the first opening. A first conduit is selectively received within the second housing. The conduit has a first cylindrical portion and a second hexagonal portion having a plurality of outer walls. The first cylindrical portion is received within the cylindrical opening and the second, hexagonal portion is received within the hexagonal opening of the second housing. The first conduit further has an opening therethrough for receiving welding wire. The second housing has an opening in a wall thereof to receive shielding gas to a cavity of the housing formed by the cylindrical opening and the hexagonal opening.  
      In accordance with another aspect of the invention, a housing assembly for use with a welding gun assembly for directing a welding wire toward a workpiece includes a housing having a first, cylindrical opening and a second, hexagonally shaped opening adjacent the first opening. A conduit is selectively received within the housing. The conduit has a first cylindrical portion and a second hexagonal portion comprising a plurality of outer walls. The first cylindrical portion is received within the cylindrical opening and the second, hexagonal portion is received within the hexagonal opening of the housing. The conduit further has an opening formed in each of the outer walls. The housing has an opening in a wall thereof to receive a fastener extending therethrough. The housing opening is aligned with one of the openings in the outer walls of the conduit and the fastener extends through the housing opening and one of the openings of the outer walls of the conduit.  
      In accordance with yet another aspect of the invention, a housing for use with a welding gun assembly has a first, hexagonal portion and a second, cylindrical portion, a first hexagonal opening and a second, cylindrical opening. A block has a plurality of walls forming a hexagonal shape. The block has a hexagonal shaped opening therein. A conduit having a hexagonal shaped portion and a cylindrical portion extending through the cylindrical portion. The hexagonal portion of the conduit is selectively received with the hexagonal shaped opening of the block.  
      According to another aspect of the invention, a welding gun assembly has a housing; a conduit extending through the housing; and a block housed within the housing, wherein the block has a passageway in one of outer walls of the block for receiving an outlet of an anti-spatter liquid supply tube or an outlet for air purging.  
      According to still another embodiment of the present invention, a welding gun assembly has a housing, and a block mounted within the housing, wherein the block has a plurality of sockets for receiving pipe-spigots of power cables, and a welding wire tube wherein the block has a passageway fluidly connecting one of the sockets for the pipe-spigots of the power cables to the socket for the pipe-spigot for the welding wire tube, wherein the passageway feeds anti-spatter liquid or an air purge to the pipe-spigot for the welding wire tube.  
      One advantage of the present invention is the provision of mounting a conduit to a housing of the welding gun in several positions without completely disassembling the gun.  
      Another advantage of the present invention is the provision of mounting the gun to a remote arm in one of several positions without completely disassembling the gun.  
      Yet another advantage of the present invention is the provision of providing a shielding gas through the housing to the conduit.  
      Another advantage of the present invention is the provision of providing anti-spatter liquid or an air purge to the welding gun.  
      Still other advantages and aspects of the invention will become apparent through the following description and the accompanying drawings.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention may take form in certain components and structures, a preferred embodiment of which is illustrated in the accompanying drawings wherein:  
       FIG. 1  is a side elevational view of a welding gun connected to a robotic arm in accordance with a preferred embodiment of the present invention;  
       FIG. 2  is an enlarged side elevational view of the rear end of the gun in accordance with a preferred embodiment of the present invention;  
       FIG. 3  is an enlarged view in partial cross-section of the rear end of the gun of  FIG. 2 ;  
       FIG. 4  is a cross-sectional view of the rear end of the gun of  FIG. 3 ;  
       FIG. 5  is a sectional view along line  5 - 5  of  FIG. 4 ;  
       FIG. 6  is a sectional view along line  6 - 6  of  FIG. 4 ;  
       FIG. 7  is a sectional view along line  7 - 7  of  FIG. 4 ;  
       FIG. 8  is a sectional view along line  8 - 8  of  FIG. 4 ;  
       FIG. 9  is a sectional view along line  9 - 9  of  FIG. 4 ;  
       FIG. 10  is an exploded perspective view of the rear end of the torch of  FIG. 3 ;  
       FIG. 11  is a side elevational view of the front end of the torch of  FIG. 1 :  
       FIG. 12  is an enlarged side elevational view in partial cross-section of the front end of the torch of  FIG. 1 ;  
       FIG. 13  is a sectional view along line  13 - 13  of  FIG. 12 ;  
       FIG. 14  is a sectional view along line  14 - 14  of  FIG. 12 ;  
       FIG. 15  is an exploded perspective view of the front end of the welding gun of  FIG. 1 ;  
       FIG. 16  is an enlarged side elevational view of the front end of the gun in accordance with an alternate embodiment of the present invention;  
       FIG. 17  is a sectional view, take along line  17 - 17  of  FIG. 16 ;  
       FIG. 18  is a side elevational view, in partial cross-section, of the front end of the torch of  FIG. 16 ; and,  
       FIG. 19  is a sectional view taken along line  19 - 19  of  FIG. 18 .  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      The apparatus shown in the accompanying drawings and described below are examples which embody the invention. It should be noted that the scope of the invention is defined by the accompanying claims, and not necessarily by specific features of exemplary embodiments.  
      For a welding operation of the type which the invention is concerned, it is the usual practice to provide a service station. This service station provides: a welding current of electricity; anti-oxidizing gas; a motor for feeding welding wire to the weld; and, optionally, a vacuum source for extracting fumes.  
      Referring now to  FIG. 1 , a robotic arm assembly generally designated by the numeral  10  includes a welding gun mount arm  12 , a welding gun front or first housing  14  and a welding gun assembly  16 . The gun mount arm  12  is a precision made instrument, typically manufactured from an aluminum alloy, preferably from 6061 aluminum alloy or the like. The gun mount arm  12  of the preferred embodiment is rotatably secured at a distal end  13  to a remote robotic machine arm  15 . The gun front housing  14  is preferably made of a plastic that is capable of maintaining its shape under tight clamping pressure. The housing is installed at a first or front end of the gun assembly. A second cylindrically shaped gun housing  18 , preferably made of brass, is installed at a second, or rear end of the gun assembly adjacent a welding wire feeder assembly  19 .  
      The welding torch further includes a gooseneck  20  which can be an insulated, thick walled copper conductor tube that is wrapped in an aluminum or stainless steel jacket that is capable of dissipating heat quickly. The gooseneck extends from the front housing  14 . Although the gooseneck  20  as shown in  FIG. 1  is bent at a particular angle, the gooseneck may be manufactured to be straight or bent at any desired angle. The torch of the preferred embodiment further comprises a thick walled nozzle  21  machined from hard drawn copper and typically has a highly conductive copper tip. The arrangement of the nozzle  21  is conventional and accordingly is not described in detail herein.  
      Referring now to  FIG. 2 , the rear housing  18  is connected to the source of welding current in the welding wire feeder  19 . An anti-oxidizing shielding gas, such as argon, carbon dioxide, or other gas as required, is fed into the housing, via a port  23 . A tube  31  is threadably connected via nut  28  to the port  23 . A conventionally used power line  24  is further connected to the wire feeder  19  via a bolted connection  25 . The wire feeder housing is secured to the housing  18  via a bolt or other suitable fastener  33  threadably inserted into opening  32  of feeder housing  19 .  
      Welding wire  26  is inserted into the housing  18 ; the wire is on a set of motorized reels  28  in wire feeder  19 ; whereby the wire may be fed forward controllably, in a conventional manner. The wire  26  may be received inside a close-coiled helical spring  30 , ( FIG. 4 ) which serves as a guide for the wire on its passage to the welding torch. A length of plastic tubing  31  is fitted to the housing  18 ; gas from the port  23  is conveyed inside the tubing to the housing. The above-described arrangements for supplying the welding current, the welding wire, and the gas, into the flexible conduit follow conventional practice as is well known in the welding art.  
      Referring now to  FIG. 3 , second housing  18  has a hollow internal cavity  40  which has a hexagonal shaped portion  42  (shown in  FIG. 6 ) and a circular shaped portion  44  (shown in  FIG. 5 ). A conduit  50 , preferably formed of brass, including a cylindrical section  51  is received within portion  44  of the housing. As seen in  FIG. 5 , conduit  50  has an opening  37  found therein for receiving welding wire  26 . As seen in  FIG. 5 , the conduit has a grooved section  52  which has a plurality of openings  54  spaced approximately 90° apart. The holes serve as passageways for gas which enters the housing via tubing  31  into opening  37  about welding wire  26  and through opening  34  in arm  35  extending from housing  18 . A pair of O-rings  56 ,  57  or other suitable sealing material is received within grooves  58  of the conduit to seal and prevent gas from traveling or escaping into the cavity  40  of the housing  18 . The conduit  50  also has a hexagonal shaped portion  59  which is selectively received by hexagonal shaped opening  42  of housing  18 .  
      The hexagonal shape of the conduit  50  allows the welding torch to be installed in different positions in the housing. Specifically, the hexagonal portion  59  has six holes  60  spaced approximately 60° apart formed in walls  63  of the conduit, as seen in  FIG. 6 . The conduit is secured into position with respect to the housing by bolt  61  or other fastener. Bolt  61  extends through opening  62  formed in arm  64  extending radially outwardly from housing  18 . The bolt is received by one of the openings  60  in hexagonal portion  59  as shown in  FIG. 6 .  
      As seen in  FIG. 4 , welding wire  26 , surrounded by the helical spring  30 , extends through opening  37  formed in conduit  50 . Shielding gas travels through tube  31  into cavity  40  of housing  18  and then into the spaced apart holes  54  in groove  52 . The gas then travels through opening  37  surrounding the wire  26  and spring  30 . The wire initially passes through an opening  65  in a separate conduit  66  which is secured to an end member  67  of conduit  50 .  
      Referring to  FIG. 4 , end member  68  of conduit  50  extends into opening  69  of cylindrical housing or sleeve portion  70 . Sleeve  70  can be made of conventional rubber or a canvas cover. Cylinder end member  68  has a threaded portion  72  which is threadably engaged with a corresponding threaded opening  74  in a mating first block  76  housed within another sleeve. Block  76  is also preferably formed of brass. A collar or flange  49  extends from the conduit  50  and abuts an end wall of the housing  18 . Referring to  FIG. 7 , first block  76  is hexagonally shaped and is selectively received within hexagonally shaped opening  78  of sleeve  70 . Thus, block  76  can be positioned in one of six positions approximately 60 degrees apart with respect to the sleeve. Alternatively, sleeve  70  can be a hollow cylinder as shown in  FIG. 10 . Block  76  can then be rotated within sleeve  70  to a variety of positions.  
      Referring to  FIG. 9 , pipe-spigots  82 ,  84  are formed on feed ends of conventionally used power cables  81 ,  83  which extend through the welding gun sleeve  70 . The pipe-spigots are inserted into sockets  86 ,  88  formed in end wall  73  of first block  76 . Plug ends  90 ,  92  of the pipe-spigots are taper fit into the sockets  86 ,  88 . Referring to  FIG. 4 , first block  76  also has a conically-shaped socket  79  for receiving a tip or pipe-spigot  94  of welding wire feed tube  93 .  
      When the plug-ends  90 ,  92  are inserted tightly in the sockets  86 ,  88 , not only are the pipe-spigots secured very well mechanically to the block, but also there is an excellent, low resistance, electrical contact between the pipe-spigots and the block. A length of flexible electrical cable is brazed or soldered into a hole in the pipe-spigots.  
      As compared with a single cable, dividing the electrical duty between two cables means that each cable can be a little less than half the current-carrying cross-section than the corresponding single cable. The reason each half-cable can be a little less than half the size is that each half-cable is contained in its own respective jacket, whereby cooling of the cable can be enhanced.  
      When only a single cable was provided, as in conventional designs, the conduit could be quite stiff. As a result, the welding operator found it quite tiring to operate the torch through a working day.  
      Splitting the cable into two and using two smaller-than-half cables, results in a greater improvement in physical flexibility and manipulability to the conduit; so much so as to extend by hours the period the operator can work comfortably.  
      In order to ensure the pipe-spigots  82 ,  84 ,  94  are pressed firmly into the sockets  79 ,  86 ,  88 , a plate or draw-ring  95 , preferably formed of steel, is provided as shown in  FIG. 8  and  10 . The approximately hexagonal shaped draw-ring has substantially U-shaped slots or cut-outs  96 ,  97 ,  98  which engage complementary recesses  99 ,  100 ,  101  defined between collars  102 ,  103 ,  104  provided on the pipe-spigots.  
      The draw-ring  95  is separate from the block and can move slightly with respect to the block to adjust the position of the pipe-spigots. When the draw-ring is moved to the right, it urges the pipe-spigots tightly into the sockets  79 ,  86 ,  88  in the block  76 ; when the draw-ring is forced to the left, it disengages the pipe-spigots from the block. The draw-ring  95  is moved to the right by tightening a bolt  105  which is inserted into an opening  106  in the ring and into a corresponding opening  107  in the block. To move the draw-ring to the left, the bolt  105  is slackened, and then the head of the bolt may be tapped to the left to drive the pipe-spigots free from the sockets. (The angle of the taper in the sockets is such that the taper is self-locking). The bolt  105  is screw-threaded into the draw-ring  95  and passes through corresponding plain hole  107  in the block  76 .  
      As described, the cable and wire assembly includes the welding wire inside its guide spring surrounded by tubing  93 ; and the two electrical cables inside their respective tubes  81 ,  83 . It will be noted that the three flexible pipes or tubes  81 ,  83 ,  93  can all have respective central internal “cores” of metal; these “cores” serve to provide excellent resistance to kinking of the pipes and tubes and to other types of mechanical failure. The entire wire and cable assembly is enclosed in sleeve  70 .  
      The wire and cable assembly is therefore very sturdy in the sense of being able to resist the abuse which is always likely to be imposed upon it in a practical welding shop, especially abuse such as snagging, twisting, and the like. On the other hand, none of the components of the wire and cable are thick or heavy, and therefore the assembly is light in weight, and is comparatively very flexible. It is easy for the operator to carry and manipulate a welding torch supported on such an assembly for long periods.  
      The components shown in  FIG. 10  can possibly be fit inside a plastic handle of conventional type. A trigger is typically included in the handle, which, when operated, activates the welding current, starts the wire feed-motor, etc., back at the service station.  
      The other front or supply end of the welding gun, adjacent to the welding torch, will now be described. At the service station or feed end of the welding gun as shown in  FIG. 1 , the requirement, as far as the physical characteristics of the components was concerned, was to support the conduit of wire and cables in a secure, robust fashion. At the torch end of the conduit, on the other hand, the requirements are different, in that now the main requirement is that the components should be light in weight; the components also should be physically small, especially as regards radial dimensions. The gooseneck  20  extends between the torch nozzle  21  and first or front housing  14 . Referring to  FIG. 12 , a second block  130 , formed of brass, is secured to an end portion of second conduit  132  which extends from end  134  of the gooseneck. Hexagonally shaped second conduit  132 , also formed of brass, is selectively received within corresponding hexagonal opening  136  of block  130  and through round or circular opening  137  of plastic housing  14 . The block  130  has a groove  143  which can receive a rib or protrusion  153  formed on the inner wall of housing  14  to secure the block within the housing.  
      Referring to  FIGS. 14 and 15 , the conduit  132  has six openings  138  which are spaced approximately 60 degrees apart on six side walls  140  of the conduit. A bolt  142  or other suitable fastener extends through an opening  144  formed in one of side walls  143  of block  130  and an opening  145  in housing  14  and extends into one of the openings  138  of the conduit to secure the conduit in one of six positions approximately 60 degrees apart with respect to the block  130 . A copper tube  139  extends through the conduit  132  and is cylindrical in shape. The tube is soldered with solder  147  to conduit  130 . The tube  139  receives the welding wire  26  and spring  30  through opening  146  and extends into gooseneck  20 . An O-ring  148  is provided to seal the tube  139  within opening  149  of block  130 .  
      A second plate or draw-ring  160  has cut-outs or U-shaped slots  162 ,  164 ,  166  for accommodating recesses  174 ,  184 ,  194  between collars  176 ,  186 ,  196 , respectively, of pipe-spigots  170 ,  180 ,  190  at supply ends of the power cables  81 ,  83  and welding wire tube  93 , as was described with respect to the pipe-spigots shown in  FIG. 10 . A bolt or elongated fastener  175  extends through opening  177  of the draw-ring for moving the draw-ring, and thereby clamping the pipe-spigots into the block  130  through opening  179  of second block  130 .  
      As clearly shown in  FIGS. 14 and 15 , the shape of the second block  130  is hexagonal. Plastic housing or sleeve  14  has a corresponding hexagonal shaped opening  152  which accommodates and provides insulation to the block. Housing  14  has a hexagonal shape to be received in one of six positions with respect to a hexagonal mounting arm bracket of a robotic arm  10 . Such a robotic arm assembly is discussed in co-pending application Ser. No. 11/178/819, filed on Jul. 11, 2005, incorporated herein by reference. The block  130  also has a hexagonally shaped opening  136  formed at an upper end which accommodates conduit  132  which has a hexagonally shaped portion  133  formed by side walls  140 .  
      The pipe-spigots  170 ,  180 ,  190  may be secured into the block  130  by means of the tapered sockets  173 ,  183 ,  193  formed in end wall  131  of block  130 , as shown, or, alternatively, the pipe-spigots may be secured into a block by means of screw-threads. The block  130 , preferably made of brass, and the plugs are brazed into the drilling as required: as a general rule in welding torches, the use of rubber seals should be avoided except where the sealed components have to be detachable. Because of the very tight restriction on the radial space envelope in the torch handle, the room available for the spigot-to-block connection, whatever its structure is severely limited. It is recognized that if this small space were occupied by a screw-thread connection, the constraints would be so tight that the screw-thread connection at that location would be unreliable. That is, if the pipe-spigot were secured into the block by means of a screw-thread connection, the screw-thread would be so small that there would be a danger that the thread would strip, even with just a small degree of abuse. It may be noted also that the components in question are generally made of brass, which material has no great resistance to the stripping of threads if over-tightened.  
      The connection as described has good electrical properties. When assembled, the pipe-spigot becomes tightly wedged into the socket, which gives an excellent, large-contact-area, electrical connection for the heavy welding currents.  
      Preferably, the pipe-spigots at the service-station end should be identical to the spigots at the torch end. Although there is no premium on radial space at the service station end of the conduit, it is simpler to have components the same.  
      Although two electrical power pipes have been described, more than two may be provided. The draw-ring and draw bolt arrangement can be used to tighten more than two pipe-spigots into place (simultaneously) into suitable sockets.  
      Referring now to  FIGS. 16-17 , an alternative embodiment is shown. Occasionally, spatter from welding at the contact tip may travel through the gooseneck  20  and into the power cables or tubes  81 ,  83  or into the welding wire tube  93 . To prevent this trend from occurring, additional feed lines  200 ,  210  may be attached to sleeve  70 . Specifically, a tube  200  may be inserted through an opening  202  in sleeve  70  and threadably connected to an opening  204  in block  76 . Opening  204  in turn is fluidly connected to openings  88  for pipe spigot  81 . Tube  210  is also inserted through opening  206  in sleeve  70  and is threadably connected to opening  208  in block  76 . Opening  208  in turn is fluidly connected to opening  89  for pipe-spigot  83 .  
      Tube  200  is used to feed an anti-spatter liquid into opening  88  for power cable  81 . The anti-spatter liquid travels through opening  88  and prevents spatter from entering and building up in the power cable opening. An example of anti-spatter liquid is robotic anti-spatter liquid provided by Clearco of 3430 G Progress Drive, Bensalem, Pa. 19020. The anti-spatter liquid may contain synthetic release agents to prevent hot spatter from sticking within the welding gun.  
      Tube  210  can be used to feed an air purge through opening  89  for power cable  83 . The air purge serves to purge excess spatter and air out of the cable line.  
      Another alternative embodiment is shown in  FIGS. 18 and 19 . Pipe spigots  300 ,  302  provided at the ends of the power cables  304 ,  306  each has an opening  308 ,  310  for allowing an air purge or anti-spatter liquid to travel through and out of the cables into a series of passageways  312 ,  314 ,  316  which are drilled into block  320 . As shown in  FIG. 19 , the passageways  312  and  314  are substantially parallel to each other and are perpendicular to passageway  316  and are all interconnected to each other. However, other configurations can be used without departing from the scope of the invention. Dowels or end caps  322  or other suitable plugs are used to plug or seal the ends of the passageways to prevent gas and liquid from escaping from block  320 .  
      The shielding gas or anti-spatter liquid travels through the cables into the passageways  312 ,  314 ,  316  via openings  308 ,  310  and into opening  324  of conduit  326  which is mounted within block  320 . The welding wire  26  and spring  30  pass through opening  324  and are surrounded by the shielding gas. An O-ring  328  is positioned in a groove  329  on the conduit  326  to prevent the gas or liquid from traveling outside the conduit.  
      The exemplary embodiment has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the exemplary embodiment be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.