Abstract:
A welding machine includes a housing having a base and a slidable rack assembly to support a gas cylinder. The rack assembly is slidably coupled to the base of the housing to move between open and closed positions. In a closed position, the rack assembly is concealed underneath the housing and in the open position the rack assembly is extended outwardly from the base to support the gas cylinder. A plurality of wheels is provided to support transportability of the welding machine.

Description:
BACKGROUND OF INVENTION 
     The present invention relates generally to welding machines and, more particularly, to a welding machine that incorporates a rack assembly to support a gas cylinder. 
     There are a large number of welding processes available for use in industry. The most common welding processes include gas tungsten arc, oxygen gas welding, and shielded metal arc welding. The gas tungsten arc welding process is sometimes referred to as TIG (tungsten inert gas) welding. TIG welding is commonly performed by a TIG welding machine utilizing an inert gas and a tungsten electrode. 
     A typical portable TIG welding machine includes a wound transformer and stabilizer that together with various electrical components condition current to be suitable for welding. The wound transformer, stabilizer, and electrical components are usually assembled into an enclosure having wheels for portability. The running gear enables the TIG welding machine to be transported to different jobs. 
     TIG welding machines carry one or more large cylinders of inert arc-shielding gases on the running gear. The gas cylinders are very heavy, often weighing as much as 180 pounds. The gas cylinders are normally supported on a horizontal pan or rack on the back end of the welding machine. The rack is welded to the running gear and is located a few inches above the floor. In that manner, the welding machine and the gas cylinders are transportable together by the running gear. 
     However, TIG welding machines are not necessarily limited to welding operations requiring gas. That is, a TIG welder may double as a stick welding machine wherein it is not necessary to carry a gas cylinder along with the welding machine. Therefore, a disadvantage of the existing horizontal racks is that it requires a great deal of space even when a cylinder is not required. Further, in some applications where such a welding machine is used for TIG welding, an alternate gas supply may be provided within a facility. For example, in some factories, gas is supplied through a conduit to various manifolds to supply gas for such welding machines. In these instances, it is not necessary to carry a gas cylinder with the welding machine. 
     In view of the aforementioned, it would be desirable to improve the design of such a welding machine and the gas cylinder rack to reduce space requirements when the welding machine is used for purposes that do not require transportation of a gas cylinder. 
     BRIEF DESCRIPTION OF INVENTION 
     The present invention solves the aforementioned problems by providing an improved rack assembly that is slidably coupled to the welding machine to allow retraction into a closed position. 
     Accordingly, one aspect of the present invention includes a welding machine having a housing, a welding power supply disposed within the housing and configured to deliver electrical power to weld metal. A rack assembly is provided that is retractably positioned within the housing to support a gas cylinder when in an extended position. 
     In accordance with another aspect of the present invention, a welding apparatus having a housing including a base and plurality of panels extending upwardly from the base and a top cover coupled to the plurality of panels to form an enclosure is provided. A welding power supply configured to deliver electrical power at levels sufficient to weld metal is disposed within the enclosure. The welding apparatus further includes a retractable cylinder support slidably coupled to the base of the housing and configured to support a gas cylinder when in a non-retracted position. The retractable cylinder support includes a base plate and a plurality of rails affixed to the base plate, wherein each of the plurality of rails includes a longitudinal slot configured to restrict extension of the rack assembly. The cylinder support further includes a pair of wheels coupled to an end of the base plate to support transportability of the welding apparatus. 
     In accordance with yet another aspect of the present invention, a method of providing support for a gas cylinder of a transportable welding machine includes the step of providing a welding machine having a housing and an extendable rack assembly. The method further includes extending the rack assembly with respect to the housing to expose a portion of a base plate and placing a gas cylinder on the portion of the base plate. 
     In accordance with yet another aspect of the present invention, a rack assembly kit to retrofit a welding apparatus to support a gas cylinder is provided. The rack assembly kit includes a cylinder support plate slidably extendable from a base of a welding apparatus and configured to support a gas cylinder when in an extended position and retract with respect to the base when in a retracted position. The kit further includes at least a pair of wheels affixed to the cylinder support plate to provide transportability of the gas cylinder. 
     Various other features, objects and advantages of the present invention will be made apparent from the following detailed description and the drawings. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     The drawings illustrated the best mode presently contemplated for carrying out the invention. 
     In the drawings: 
     FIG. 1 is a perspective view of a welding machine incorporating a rack assembly constructed in accordance with the present invention and illustrating the rack assembly thereof in its closed position. 
     FIG. 2 is a perspective view, similar to FIG. 1, illustrating the rack assembly in an open position and supporting a gas cylinder shown in phantom. 
     FIG. 3 is an exploded perspective view of the rack assembly of FIGS. 1 and 2. 
     FIG. 4 is an assembled top perspective view of the rack assembly of FIG. 3 in a closed position. 
     FIG. 5 is similar to FIG.  4  and illustrates the rack assembly in an open position. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is a perspective view of a welding machine  10 , incorporating a retractable rack assembly  12 . The welding machine  10  comprises a housing  14  having a base  16 , and a plurality of panels spaced apart from one another and extending upwardly from the base  16 . The plurality of panels includes a back panel  18 , a front panel  20  with control knobs  22  and a pair of side panels  24 . A top cover  26  is secured to the panels that collectively form an enclosure. The top cover  26  has an opening  28  to allow access to the interior of the housing  14 . Panels  20 ,  24  and top cover  26  are preferably fabricated from blank sheet metal as is well known in the art. A pair of support bars  30  extend outwardly from housing  14  to support an upper portion  32  of a gas cylinder  34  as best shown in FIG.  2 . 
     Enclosed in the housing  14  is a welding power supply (not shown) as well as a prime mover such as an engine (not shown) to drive a generator. Electrical power from the generator is converted by various electrical components into power suitable for welding, as is well known in the art. 
     A rack assembly  12  is slidably coupled to the base  16  of the housing  14  to allow retraction of the rack assembly  12  into a closed position. In the closed position, rack assembly  12  is engaged with base  16  of housing  14 . A locking device, preferably a pair of pins  36   a  and  36   b , couples the rack assembly to the base on both sides of the housing. Self-tapping screws may also be used to couple the rack assembly to the base. Wheels  38 ,  40  and handle  42  enables the welding machine  10  to be maneuvered and transported with ease to different job sites. Further, each wheel  38  is equipped with a wheel-locking mechanism  39  to limit the transportability of the welding machine. Wheel  40  is coupled to an undersurface of the base  16  and is configured to freely pivot to assist with turning of the welding machine. 
     FIG. 2 is a perspective view similar to FIG. 1 illustrating the rack assembly  12  in an open or disengaged position and supporting a gas cylinder  34  shown in phantom. In an open or retracted position, rack assembly  12  is extended outward away from the base  16  and is configured to support the gas cylinder  34  for supplying shielding gas during welding operation. 
     FIG. 3 is an exploded view of the rack assembly  12  of FIGS. 1 and 2. The rack assembly  12  has a base plate  44  and a plurality of rails  46  which are spaced apart and fixed to the base plate  44 . Preferably the base plate  44  is fabricated from sheet metal and has two opposed ends, an upwardly standing lip  48  at one end and a U-shaped channel  50  at the other end. Lip  48  is formed by bending upward one end of the base plate  44  in a general right angle and thereby operates to assist in preventing the gas cylinder  34  from slipping off the base plate. Similarly, a plurality of guides  52  are formed within the base plate  44  and extend upwardly from the base plate. The guides  52  are configured to support a lower portion  35  of the gas cylinder. 
     Still referring to FIG. 3, each rail  46  has a first end  54   a  and a second end  54   b . The second end  54   b  of each rail has a longitudinal slot  56  that engages a rod (not shown) of the base  16 . The rail is disposed within the slot  56  to limit the retractable range of base plate  44 . Slot  56  and holes  58 ,  62  may be formed by properly cutting the middle of a rectangular sheet metal and punching holes  58 ,  62  on each end of the sheet metal. The sheet metal may then be bent downwardly along fold lines  64  and welded to the base plate  44 . However, other construction techniques are contemplated and within the scope of the present invention. The first end  54   a  of each rail has also two holes  58  which are axially aligned with a hole on a side of base  16  of the housing and then a pin  36   a  is inserted therethrough to fasten the rack assembly. 
     At least one axle, and preferably two identical axles  60 , are attached to corresponding first ends  54   a  of the two rails  46 . Each wheel  38  is mounted on an axle  60  that is inserted through a pair of holes  62  and securely fastened to the rail by a cotter pin and a washer, or other securing means. Referring now to FIG. 4, an assembled top perspective view rack assembly  12  in a closed position is shown. As described above, when the rack assembly is constructed and assembled, slots  56  engage with corresponding grooves  66  of base  16 . The length of slot  56  together with a rod limit the extendable distance the rack assembly  12  may travel FIG. 5 is similar to FIG.  4  and illustrates the rack assembly  12  in an open position. As shown, rack assembly  12  may be extended to expose a portion of the base plate  44  such that gas cylinder  34  may be supported thereon. Additionally, rack assembly  12  is constructed such that the welding machine may be transported while the gas cylinder is being supported. To provide additional security, a strap  31  fastened to support bars  30 , FIG. 1, may be implemented to limit transverse movement of the gas cylinder. 
     Accordingly, one embodiment of the present invention includes a welding machine having a housing, a welding power supply disposed within the housing and configured to deliver electrical power to weld metal. A rack assembly is provided that is retractably positioned within the housing to support a gas cylinder when in an extended position. 
     In accordance with another embodiment of the present invention, a welding apparatus having a housing including a base and plurality of panels extending upwardly from the base and a top cover coupled to the plurality of panels to form an enclosure is provided. A welding power supply configured to deliver electrical power at levels sufficient to weld metal is disposed within the enclosure. The welding apparatus further includes a retractable cylinder support slidably coupled to the base of the housing and configured to support a gas cylinder when in a non-retracted position. The retractable cylinder support includes a base plate and a plurality of rails affixed to the base plate, wherein each of the plurality of rails includes a longitudinal slot configured to restrict extension of the rack assembly. The cylinder support further includes a pair of wheels coupled to an end of the base plate to support transportability of the welding apparatus. 
     In accordance with yet another embodiment of the present invention, a method of providing support for a gas cylinder of a transportable welding machine includes the step of providing a welding machine having a housing and an extendable rack assembly. The method further includes extending the rack assembly with respect to the housing to expose a portion of a base plate and placing a gas cylinder on the portion of the base plate. 
     In accordance with yet another embodiment of the present invention, a rack assembly kit to retrofit a welding apparatus to support a gas cylinder is provided. The rack assembly kit includes a cylinder support plate slidably extendable from a base of a welding apparatus and configured to support a gas cylinder when in an extended position and retract with respect to the base when in a retracted position. The kit further includes at least a pair of wheels affixed to the cylinder support plate to provide transportability of the gas cylinder. 
     The present invention has been described in terms of the preferred embodiment, and it is recognized that the equivalent, alternatives, and modifications, aside from those expressly stated, are possible and within the scope of the appending claims.