Abstract:
A manual welding safety disconnect to provide the welder the ability to stop current flow to a TIG (GTAW) torch or a stick (SMAW) welding lead where it attaches to the supply cable which would allow the operator to prevent further current flow by causing a misalignment of the enclosed electrical contacts. Misalignment of the electrical contacts by a rotation around the inert gas tube permits the operator to immediately shut off the welding current while still allowing the gas flow in the TIG version. This configuration also is more convenient for the welder since he would not have to leave his work area. This safety device would reduce the risk of electric shock, accidental arc strike, and arc flash. This device can isolate any one lead or torch to produce a safe zero energy mode even if operating from a multibank power supply.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     This invention relates to a welding safety disconnect to be used in stick welding (SMAW) or TIG welding (GTAW) to disable current flow at the point of operation while maintaining all connections including the inert gas connection for a TIG torch.  
         [0003]     2. Description of the Prior Art  
         [0004]     The use of welding has been popular for quite some time and is used frequently in construction, all forms of metal fabrication, ship building and in other uses. The welding process is reliant on the supply of current to the lead or torch that causes metal to heat up and melt, thus creating a weld and joining the work piece materials.  
         [0005]     Shielded Metal Arc Welding (SMAW) is frequently referred to as stick or covered electrode welding. Stick welding is among the most widely used welding process. The flux covering the electrode melts during welding. This forms the gas and slag to shield the arc and molten weld pool. The slag must be chipped off the weld bead after welding.  
         [0006]     Gas Tungsten Arc Welding (GTAW) is frequently referred to as TIG welding. TIG welding is a commonly used high quality welding process. TIG welding has become a popular choice of welding process when high quality, precision welding is required.  
         [0007]     In TIG welding an arc is formed between a nonconsumable tungsten electrode and the metal being welded. Gas is fed through the torch to shield the electrode and the molten weld pool.  
         [0008]     In welding the heat to melt metal is a result of an electrical arc produced by a very high current source at a voltage normally less than 50 volts, such as to be within normally accepted ranges of operating voltages such as to present a nonlethal threat to the user. While welding torches or leads can be disconnected from the cabling, it is desirable to have a positive current disconnect which allows a continued attachment of the welding lead or torch to the supply lines while rendering a complete off and safe condition of the current being supplied.  
         [0009]     Welding leads or torches are traditionally fully detachable from said supply cable. However, to completely restrict the electric current from reaching the weld point requires the torch or lead to be completely removed or the power supply to be turned off. The removal of the lead or torch is a cumbersome and often time consuming process.  
         [0010]     To shut down the power supply to the welding torch is also not a convenient option because the welding is often being performed hundreds of feet from the power supply. Also, many facilities or job sites use multi bank machines or power supplies which would require stopping 6 or 8 welding processes when the machine is turned off to accommodate only one user.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention was developed to provide a safer and more effective method for welders to quickly and deliberately disconnect the current from the lead or torch when not in use, or place the torch or lead in a safe mode so the tungsten tip or rod can safely be changed with no risk to the operator. Under standard and currently employed methods, an improperly placed lead or torch can result in shocking third parties who come into contact with the unattended torch or lead. Also, an accidental arc strike could be caused which could result in electrical shock or the flash could cause Welder&#39;s Eye. Certain types of ultraviolet radiation caused by welding can produce an injury to the surface or mucous membrane of the eye called “Welder&#39;s Eye” or “Arc Flash.” These are common names for “Conjunctivitis” which is an inflamation of the mucous membrane of the front of the eye.  
         [0012]     Further, it is frequently desired in TIG welding operations to completely stop the current from flowing into the operator-controlled torch while still allowing the user to direct the inert gas onto the weld and work piece. The present invention comprises a device that can be co-located to a stick (SMAW) welding lead or a second version that can be co-located to a TIG (GTAW) welding torch, through the current supply. A push-pull, or rotatable disconnect mechanism provides a positive current cutoff system to disable the current to the torch or lead without disconnecting the supply line. The invention facilitates placing the torch or lead in a safe mode easily, without any disassembly and without undue delay or inconvenience.  
         [0013]     A push-pull or rotatable pair of interlocking cylinder-like halves are aligned coaxial about the power supply line to form a snug, latching or lockable fit for stick welding or gas tight fit for TIG welding which would allow the gas to continue to communicate with the torch while providing terminals to disconnect the high current, low voltage source of power to the torch or lead when the cylinder halves are rotated or pushed/pulled.  
         [0014]     The safety disconnect of the present invention utilizes a push-pull or a rotational disconnect action in which a separation is created between the electrical connection in the TIG torch or stick torch lead and the power source cable. Normally the cable connecting a welding machine to the torch is comprised of a single conductor or a single conductor in the outer radius of the connecting cable surrounding a gas tube for inert gas in TIG welding. The disconnect of the present invention is best considered as comprising three main components for TIG welding, including a continuous inner feed tube through which the inert gas can flow and a top and bottom outer interlocking cavity through which welding current can flow when internal conductors are aligned. The center gas tube is unnecessary for stick (SMAW) welding.  
         [0015]     The outer housing and inner housing of the interlocking disconnect switch are similarly constructed. Integrated within both sections are the electrical conducting electrodes and the electrically insulating materials which can be axially rotated to align the conducting electrode sections of the two halves to engage the electrodes to complete the conductor leading to the welding torch. The rotation of the switch provides a strong compression connection between both sets of electrodes which cause contact so current may flow from the source or welding machine line to the torch or lead when the safety disconnect is in the closed or “on” position.  
         [0016]     The general composition of the handle components and the disconnect which is located in or near the torch handle or lead will be constructed out of an electrically insulated material so that electrical current will only be able to pass through the aligned connector and when the corresponding contacts are aligned.  
         [0017]     The electrical conductors and insulators are brought into alignment by rotating or pushing the outer portions of the disconnect between the open and closed positions. When in the close (i.e. operational) position the contacts in the top and bottom of the safety disconnect will be directly aligned. Upon rotation or a pulling action, the conductors will lose contact with one another and align with an insulator to prevent current flow and place the torch or lead in a “safe” mode.  
         [0018]     The center feed tube for the inert gas (for TIG i.e. GTAW) will remain unaffected by these actions since the outer cavity continuing the electrical conductors and insulators shall be able to freely traverse around the concentrically located inner feed between its open and closed positions.  
         [0019]     An alternative embodiment of the present invention provides for an integration of the switch disclosed into the handle of a typical welding torch. Locating the housing of the switch components at or near the end of a torch handle which otherwise connects to the welding current cable and gas tube insert allow the invention to operate in the fashion disclosed to provide the convenience of the switch or rotational mechanism being integrated into the handle of the torch.  
         [0020]     Accordingly, it is the object of the present invention to provide a positive current disconnect mechanism which does not require the operator to disconnect the torch from the welding current line to operate.  
         [0021]     It is further an object of the present invention to provide a positive current disconnect mechanism that will allow a MIG or stick welding torch system to remain connected to a welding machine which is still energized while providing easy current disconnect means available to welding torch operator at the welding location.  
         [0022]     It is yet another object of the present invention to provide a quick current disconnect mechanism for a conventional TIG or stick welding torch which provides visual indication of whether the current is selected in the “on” or “off” position.  
         [0023]     It is a further object of the present invention to provide a current disconnect mechanism which allows a continuous inert gas to feed through the mechanism which disconnecting the current conductors to a conventional TIG torch. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]      FIG. 1A  is a pictorial view of the entire invention displaying the safety disconnect mechanism placed in line with a welding torch wire.  
         [0025]      FIG. 1B  is a cutaway view of the safety disconnect mechanism illustrating the internal electrode connections.  
         [0026]      FIG. 1C  is a sectional view of the safety disconnect mechanism shown in  FIG. 1B .  
         [0027]      FIG. 2A  is a pictorial view of the entire safety disconnect mechanism illustrating the rotation of the outer housing and selection of an “on” or “off” position.  
         [0028]      FIG. 2B  is a sectional view of safety disconnect mechanism illustrating the position of the internal electrodes when the switch is in the “off” position.  
         [0029]      FIG. 2C  is a sectional view of the switch as shown in  FIG. 2B  with the electrodes arranged in the “off” position.  
         [0030]      FIG. 3A  is a sectional view of the safety disconnect mechanism illustrating the position of the internal electrodes with the switch in the “on” position, and further illustrating the inert gas tube concentrically positioned through the axis of the switch mechanism.  
         [0031]      FIG. 3B  is a sectional view of the switch as shown in  FIG. 3A , further illustrating position of the inert gas tube coaxially positioned through the rotating cylinders which comprise the switch.  
         [0032]      FIG. 4  is a pictorial diagram of the safety disconnect mechanism shown integrated into the handle of a typical welding device. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0033]     The invention will now be described with reference to the various figures, wherein like-numerals refer to like-parts. Turning to  FIG. 1 , the entire switch  10  is shown in the “on” position. Switch outer housing  16  is mated slidably to the inner housing  18  shown in a sectional view in  FIG. 1B . Switch  10  can be placed anywhere in the welding torch current line of a typical welding machine and torch operation. However, it should be appreciated that switch  10  can be of most effect when it is placed in the general vicinity of the welding torch where an operator will have easy access to the switch mechanism. Switch  10  is comprised of the machine line  14  bringing current from a typical welding machine. Torch line  12  is the conductor presenting current from switch  10  to a welding torch in the vicinity of the switch. Outer rotational knob  30  is used to rotate the mechanism internally where lower rotational knob  32  can be held in a stationary position to allow the inner housing  18  and outer housing  16  to rotate in relation to each part.  
         [0034]      FIG. 1B  shows switch  10  in the closed position, wherein current flows through the switch because of the continuity presented by the connection of outer electrode  20  and inner electrode  22 . It can be seen in  FIG. 1B , conductor  14  attaches to inner electrode  22  at connection  26 , while the welding torch line  12  is connected to the outer electrode  20  at wire connection  24 . Outer electrode  20  and inner electrode  22 , when placed in the “on” position contact each other at location  28 , illustrated in  FIG. 1 B . Electrodes  20  and  22  are fashioned such as to have sufficient contact area when in the closed or “on” position as to prevent appreciable resistance between the electrodes when they are contacting each other as shown in  FIG. 1B . When switch  10  is in this position, current flows because of the continuity presented by electrodes  22  and  20  by completing the circuit of the current through the switch, to the welding torch and the electrode or tip of the torch which completes the current through the ground connection normally attached to the work piece being welded in a typical operation.  
         [0035]      FIG. 1C  is a sectional view through  FIG. 1B  as shown providing an end view of the outer electrode  20  and inner electrode  22  when they are rotated into the “on” position, thereby allowing current to flow from the welding machine to the welding torch. It should also be appreciated that the means of contact between electrode  20  and electrode  22  can be accomplished through a variety of different means. In the example displayed in  FIG. 1B  and  FIG. 1C , the electrodes rotate in a coaxial fashion intersecting each other to contact across the broad end of each electrode as shown specifically in  FIG. 1C . In a similar fashion, electrodes  20  and  22  can intersect each other by direct contact end on end and accomplish the same purposes of the invention. The object in the rotational switch is to be sure that there is ample conductivity between the electrodes to provide continuity when the switch is selected on and not introduced appreciable resistence between the two electrodes to prevent a drop in current across the switch. The switch electrodes would be constructed of a high conductivity material, whether copper or even silver plated contacts to prevent oxidation or resistance from forming in the switch elements. Since switch housing  16  can be constructed in a fashion to allow it to be dismantled from time to time, electrodes  20  and  22  can be subject to inspection or cleaning occasionally in the normal maintenance process.  
         [0036]     As can be seen in  FIG. 1C , the outer housing  16  and inner housing  18 , both of which comprised with switch  10  have a drag resistance or ratcheting mechanism which allows the two halves to be rotated into the closed position with the outer and inner housing reaching a stopped position when electrode  20  and electrode  22  are aligned to conduct current. It can be appreciated by one skilled in the art that there are various mechanisms which could be used to allow the inner and outer housings suggested in  FIG. 1B  and  FIG. 1C  to mate coaxially such as to provide for a positive stop position when the internal electrodes are aligned as required in either the current “on” or current “off” position. Such a detent or ratcheting mechanism can provide sufficient resistance such as to cause the outer housing  16  and inner housing  18  to require enough force as to prevent inadvertent rotation of the halves other than when the operator desires to have the halves rotate under application of sufficient torque. It is also possible to provide entirely different housing mechanisms which provides the same internal connections or disconnections but applies lateral force through a snap-on or snap-off mechanism in an alternate embodiment.  
         [0037]     In the present invention it is useful to have a positive flag condition illustrating whether the switch is in the “on” or “off” position due to rotation. As shown in  FIG. 1A , when the electrodes are aligned to provide for continuity through switch  10 , status window  50  displays an “on” condition flag. Window  50  is aligned to the surface of switch inner housing  18  so that when the switch is aligned to conduct current, the “on” printing or other colored or warning flag condition can be seen through status window  50  which shows through outer housing  16 .  
         [0038]     Turning now to  FIG. 2A , switch  10  is shown in the “off” position. It can be appreciated, rotating the switch can be accomplished by rotating the two halves of the switch to accomplish through upper rotation knob  30  and lower rotation knob  32 , each separately connected to the outer housing  16  and the inner housing  18  respectively. Rotating one housing of switch  10  in one direction while holding the other stationary, the internal electrodes can be disaligned as shown by housing rotation  52  in  FIG. 2A .  
         [0039]      FIG. 2B  is a sectional view of the switch selected in the “off” position, wherein it can be appreciated how electrodes  20  and  22  are disaligned with each other to break the continuity of the welding torch current line. A sectional view of switch  10  in the “off” position is shown in  FIG. 2C  where the electrodes are separated such that current flow is stopped and the welding torch is rendered current safe. Once again, it can be appreciated from  FIG. 2C  how a ratcheting mechanism and positive detents or stops can be molded into the housing to provide a positive feel for the stop position when the switch is rotated  90  degrees from the “on” position.  
         [0040]      FIG. 1  and  FIG. 2  all illustrate switch  10  in its simplest configuration for use with a welding torch engaged in stick welding operation. In TIG welding, a single current conductor is used to apply high current, low voltage power to the welding torch but an inert gas is also conducted up the same cable to provide such welding gases to the gas cup built into a typical TIG welding torch. In such a case, it can be appreciated that while positive current shutoff is desired for the same safety reasons, switch  10  must provide for an internal, coaxial gas tube to allow the welding gas to travel uninterrupted through the switch whether or not the switch is in the positive contact or current “off” position. In fact, many times it is desirable to allow the welding gas to continue to flow to the welding torch while the current is shut off momentarily or for a longer period of time.  
         [0041]     In turning to  FIG. 3A  and  FIG. 3B , a variation of the invention is shown, whereby switch  10  contains a gas tube which travels through switch  10  as illustrated, allowing gas tube  60  to move through the interior area of switch  10  such that the gas tube is undisturbed by the rotating outer housing  58  and inner housing  60 . In accordance with this variation, it can be appreciated that gas tube  60  continues to allow flow of an inert gas to the welding torch even though switch  10  can be used in the fashion described above to cut off the current to the torch.  
         [0042]     The variation of switch  10  shown in  FIG. 3A  would be necessary when using the invention in conjunction with TIG welding so that a typical TIG torch as shown in  FIG. 4  would have inert gas available to it for use in normal operation. The inert gas tube  60  as shown in  FIG. 3A  and  FIG. 4  could be of a flexible design such as is normally used in welding cables for such applications such that rotation of switch  10  ninety degrees to select an “on” or “off” position would not cause undue deformity of tube  60 . It is also possible to complete switch  10  such that gaskets are formed at the interface of tube  60  as shown at  62  and  64  in  FIG. 3A . With rubber O-rings or gasket designs, it would be a simpler matter to retrofit an existing TIG welding line such as cut the line, install switch  10  on the line and reconnect the gas line through tube  60 , thereby allowing a simpler retroactive installation of the safety switch  10  without need to replace the entire welding line from the welding machine to the welding torch.  
         [0043]     In keeping with the improvements described in the present invention, switch  10  can be integrated in a welding torch handle where torch line  12  actual connects to the lower end of a conventional welding torch as illustrated in  FIG. 4 , so that the switch can be part of the lower portion of a handle. Whether switch  10  is situated several feet from the welding torch or integrated in the handle as suggested in  FIG. 4 , the operation of the switch would be similar, if not identical to the internal electrode configuration such as to allow the current to be positively locked off while the welding machine is still selected in the “on” position. As can be seen from  FIG. 4 , the switch housing is integrated into the handle, thereby providing that half of the housing is stationary with the welding torch handle. Either torch  66  can be rotated to select the “off” position, or the housing of switch  10  can be rotated with the cable and gas tube  60  therein in order to select the “off” position. Adding switch  10  to the handle of torch  66  adds some weight to the torch, but in many instances is a preferred design depending on the application and size of the torch.  
         [0044]     The advantage of the switch located in an existing cable removed from the torch  66  allows for retrofitting existing torch designs which the handles do not necessarily adopt well to the integration of the switch as suggested in  FIG. 4 . The invention as disclosed provides for retrofitting existing welding apparatus by cutting the cable at a point convenient for the location of switch  10  and attaching the electrodes to machine line  14  and torch line  12 . It is also possible to retrofit TIG welding apparatus by cutting the gas tube traveling within the same cable and affixing the gas tube switch  10  to allow continuity through the switch as shown in  FIGS. 3A and 3B . The inert gas supplied in TIG welding is normally not under high pressure and does not present a hazard or a risk by retrofitting the gas tube as suggested to allow for the switch to be retrofitted onto existing cables and welding lines for torch apparatus in the field.  
         [0045]     A modification to the system would incorporate a different visible indica of status into the safety disconnect. The top portion and the bottom section of the safety disconnect could have another set of electrical contacts than when in the on position would provide current to a small light device, such a light emitting diode in the handle section of the lock indicating whether the device was in the “on” or “safe” mode. This would allow anyone unsure of the condition of the torch or lead to determine its status immediately and unmistakenly by additional means other than physical observation of the disconnect so as to be sure of the condition of the torch or lead.  
         [0046]     A further modification would include a safety locking mechanism that would require the user to depress a button in conjunction with twisting or pushing to restore current to the torch or lead. This button would have been automatically released during the twisting or pulling action to remove the current. This would prevent any accidental restorations of current.  
         [0047]     Although the invention has been described in terms of the preferred embodiment and with particular examples that are used to illustrate carrying out the principles of the invention, it would be appreciated by those skilled in the art that other variations or adaptation of the principles disclosed herein could be adopted using the same ideas taught herewith. Such applications and principles are considered to be within the scope and spirit of the invention disclosed and are otherwise described in the appended claims.