Patent Application
20140131337
Not Applicable.
Not Applicable.
This invention relates to electrode holders used in stick welding; also referred to as shielded metal arc welding (SMAW). More specifically, the invention is an electrode holder which routinely and reliably cuts off power upstream of the electrode holder during electrode changes without requiring conscious action by a user.
As noted in U.S. Pat. No. 3,828,160, the prior art discloses switch constructions disposed in the handle portions of electrode holders such as U.S. Pat. Nos. 3,249,734, 1,589,977; and 1,883,807. In contrast, U.S. Pat. No. 3,596,052 discloses the typical and more common type of handle construction which has no provision for disconnecting the power.
Again as noted in U.S. Pat. No. 3,828,160, in the construction disclosed in each of these patents, the power disconnect switch requires intricate switch design with a plurality of moving parts, all requiring the operator to manipulate the switch by hand. Due to the design of the switch throw, the welder must remove his heavy working gloves and operate a switch button or manipulate a plurality of switch buttons. Likewise, when the power button is to be energized, the reverse procedure is necessary. Furthermore, the maintenance of the intricate designs disclosed in the prior art is difficult.
Welding machines, by their nature, are employed in very hostile environments and receive very rough use. They are subjected to dirt and dust as well as temperature extremes and abuse by the operators. Moving parts are oftentimes rendered inoperative due to dirt and dust and delicate mechanisms are oftentimes damaged due to the rough treatment which this type of equipment is subjected to. Furthermore, the environment in which this equipment is used requires the operator to wear heavy, long-cuffed gloves which substantially interfere with finger and hand dexterity. U.S. Patent Publication Number 20060086709 describes an electrode holder for use in welding with a power isolating switch on the handle. The power isolating switch can lock the electrode against removal when the power isolating switch is in the “on” position. When the power isolating switch is moved to the “off” position, the electrode can be removed. The electrode holder provides significant safety improvements to minimize a shock hazard to a user changing electrodes.
U.S. Pat. No. 7,825,351 describes a hand held electrode holder fitted with a power on/off switch on the handle of the electrode holder and a trigger to open the clamping jaws that clamp the electrode. The holder has internal parts which operate such that the trigger cannot open the clamping jaws while the switch is in the power on position thereby reducing the possibility of an electric hazard when changing electrodes.
U.S. Pat. No. 3,828,160 describes an electrode holder with power disconnect. The '160 electrode holder is fitted with a plug and socket type of electrical connection mounted inside the insulated handle portion of the electrode. The plug and socket are mounted for relative sliding movement inside the handle.
U.S. Patent Publication Number 20060237410 describes a manual welding safety disconnect which allows a welder 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. None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.
The invention is directed to an electrode holder system used in stick welding. The electrode holder comprises a handle having first and second opposite ends, and an electrode gripping mechanism fitted to the first opposite end of the handle. The electrode gripping mechanism comprises upper and lower jaw members. The upper jaw member extends above the handle for a distance from the first opposite end of the handle.
In one non-limiting embodiment a handle switch is located on the handle and below the upper jaw member. The handle switch is in operable communication with a power shutoff located between the electrode holder and a power supply. The location of the handle switch obviates the need for conscious effort on the part of a user to electrically isolate the electrode holder when changing an electrode. More specifically, the location of the handle switch ensures that during normal operation of the electrode holder a user is obliged without conscious effort to press the handle switch when gripping the handle thereby supplying power to the electrode holder, and upon replacing an exhausted electrode a user, without conscious effort, releases the handle switch thereby cutting off power to the electrode holder.
Since the power shutoff is located upstream of the electrode holder no electrical power is supplied to the electrode holder when the user is changing or fitting an electrode between the upper and lower jaw members thereby avoiding accidental electrocution of the user. Also, if the electrode holder is dropped while live, the power is immediately shut off upstream of the electrode holder thereby avoiding accidental electrocution of the user and/or nearby workers. As such, the invention offers significant safety improvements to minimize a shock hazard to a user changing electrodes.
Similar reference characters denote corresponding features consistently throughout the attached drawings.
This invention is directed to electrode holders used in stick welding; also referred to as shielded metal arc welding (SMAW). In one embodiment, the invention is an electrode holder 100 with the capability of cutting off power upstream of the electrode holder 100 during electrode changes without requiring conscious action by a user. In another embodiment, the invention is an electrode holder 100 in combination with a power shutoff device 110. The power shutoff device 110 is used to cutoff power upstream of the electrode holder 100 depending on the status of the handle switch 195. The power shutoff device 110 can be a modular unit located between the electrode holder 100 and a welding power source 220 (as shown in
It is to be understood that the terms “top”, “bottom”, “side”, “front”, “rear”, “upper”, “lower”, “vertical”, “horizontal”, “height”, “width”, “length” and the like are used herein merely to describe points of reference and do not limit the present invention to any specific orientation or configuration. The claimed apparatus and components may be of any size, shape or configuration suitable for operation of the apparatus and may be constructed of any suitable materials.
The electrode holder 100 comprises a handle 120 in the shape of a tube and having front 140a and rear 140b opposite ends, handle surface 150, a handle switch 195, and an electrode gripping mechanism 170 fitted to or proximate to the front opposite end 140a of handle 120. The handle switch 195 (shown schematically in
The electrode gripping mechanism 170 can be any suitable electrode gripping mechanism for gripping an electrode 160 such as upper and lower jaw members 180a and 180b, respectively.
The upper jaw member 180a extends above the handle 120 for a predetermined distance from the front opposite end 140a of the handle 120. The predetermined distance can be any suitable distance such that a user is obliged without conscious effort to place their hand (typically an insulated gloved hand) under the upper jaw member and press down the handle switch 195, which can be a trigger switch 200, when gripping the handle 120 to perform stick welding operations; and, further wherein a user is obliged to release the handle switch 195, which can be a trigger switch 200, upon gripping and pressing the upper jaw member 180a towards the surface 150 of the handle 120 via pivot point 195 to release an electrode 160 from between the upper and lower jaw members 180a and 180b.
The predetermined distance can be in the range 10% to 100% of the length of the handle 120, wherein the length of the handle 120 is defined as the distance between the front 140a and rear 140b opposite ends of handle 120. More preferably, the predetermined distance can be in the range 20% to 80% of the length of the handle 120, wherein the length of the handle 120 is defined as the distance between the front 140a and rear 140b opposite ends of handle 120. Still more preferably, the predetermined distance can be in the range 30% to 60% of the length of the handle 120, wherein the length of the handle 120 is defined as the distance between the front 140a and rear 140b opposite ends of handle 120.
The handle switch 195 is located on any suitable part of the handle 120 which obliges a user to release the handle switch 195 upon using the jaws 180a and/or 180b to release or attach an electrode 160 to the electrode holder 100. In this manner a user 188 is consciously or unconsciously obliged to remove their hand 190 from pressing the handle switch 195 when, for example, an electrode 160 needs to be replaced or otherwise inserted between jaws 180a and 180b. It is also preferred that the handle switch 195 is located in such a position on the handle 120 that a user 188 is obliged to press the handle switch 195 upon gripping the handle 120 to perform a stick welding operation and more preferably to release the handle switch 195 upon pressing upper jaw 180a towards handle surface 150 about pivot 185 to release or insert a fresh electrode 160 between upper and lower jaw members 180a and 180b. The handle switch 195 can be a trigger switch 200 as shown, for example, in
In one non-limiting embodiment a trigger switch 200 is located on the handle surface 150 below the upper jaw member 180a; it has been found that locating a trigger switch 200 below the upper jaw member 180a obliges a user 188 to press the trigger switch 200 when gripping the handle 120, and conversely upon changing a used electrode 160 the user's hand 190 must be used to press the upper jaw member 180a inwards towards the handle surface 150, the process of pressing the upper jaw member 180a requires the user 188 to remove his/her hand 190, typically a gloved hand, out of the way to avoid blocking the upper jaw member 180a which needs to be pressed downwards towards the handle's surface 150 in order to release a spent electrode 160 from between the jaws 180a and 180b. The upper jaw member 180a also needs to be pressed downwards towards the handle's surface 150 in order to insert a fresh electrode 160 between the jaws 180a and 180b.
The upper jaw member 180a has an electrode grip end 187a and a hand grip end 187b, and during electrode changes the hand grip end 187b is pressed inwards towards the handle surface 150 to release a used electrode or to fit a fresh electrode between the upper and lower jaws 180a and 180b (see
In one non-limiting embodiment at least one of the jaws 180a, 180b is in contact with or forms part of a conductive pathway 182; in
The handle switch 195 forms part of a power cutoff circuit 360 (see
In one non-limiting embodiment a trigger switch 200 is located on the handle 120 below the upper jaw member 180a. The length of the handle 120 is selected to ensure that a user's hand has to be positioned over the handle switch 200 during welding, and the location of the handle switch 200 below the upper jaw member 180a ensures that when an electrode 160 is withdrawn or inserted between jaws 180a and 180b the user's hand 190 has to be removed from underneath the upper jaw 180a to allow the upper jaw 180a to be pressed inwards towards the handle surface 150. The handle switch 195 is in operable communication with a power shutoff device 110 located between the electrode holder 100 and a welding power source 220. The handle switch 195 defaults in an up position and in response to down pressure by a user's hand 190 the handle switch 195 moves inwards and allows electrical current to run through power cutoff circuit 360 thereby causing cutoff switch 400 to close and electrical current to transfer from a first power line 240 to a second power line 260 and thence to electrode holder 100 and thence to electrode 160. The second power line 260 includes a power cable 265, first circuit cutoff line 380a, and third circuit cutoff line 380c (see
Since the power shutoff device 110 is located upstream of the electrode holder 100 no electrical power is supplied to the electrode holder 100 when the user is changing or fitting an electrode 160 between the upper and lower jaw members 180a and 180b thereby avoiding accidental electrocution of the user. Also, if the electrode holder 100 is dropped while live, the switch 200 springs up and power is immediately shut off upstream of the electrode holder 100 thereby avoiding accidental electrocution of the user and/or nearby workers. As such, the electrode holder 100 offers significant safety improvements to minimize a shock hazard to a user changing electrodes.
The power shutoff device 110 comprises a housing 112 and a cutoff switch 400 located therein. The cutoff switch 400 can be a solenoid switch 410 (shown schematically in, for example,
The cutoff switch 400 is located between the first and second power lines 240 and 260. When the cutoff switch 400 is in a closed position electrical power can flow from the first power line 240 to the second power line 260 and hence to the electrode holder 100. When the cutoff-switch 400 is in an open position electrical power can not flow from the first power line 240 to the second power line 260 and power is cutoff upstream from the electrode holder 100.
The cutoff switch 400 defaults to an open position preventing electrical power reaching the electrode holder 100 from a welding power source 220. The cutoff switch 400 moves to a closed position in response to current received from power cutoff circuit 360 thereby allowing current to pass from first power line 240 to the second power line 260 and more particularly to the holder power cable 265 located inside the first power line 260. In addition to the cutoff switch 400 the power cutoff circuit 360 also includes a circuit power source 420 and handle switch 195; the handle switch 195 can be a trigger switch 200. Current only flows to the cutoff switch 400 when the handle switch 195 is in a pressed down condition; the position of the handle switch 195 ensures that a user's hand presses the handle switch 195 inwards upon gripping handle 120, and unconsciously releases the handle switch 195 when pressing the upper jaw member 180 inwards towards surface 150 to release a used electrode or to insert a fresh electrode 160.
The circuit power source 420 can be, for example, a non-rechargeable battery or a chargeable battery. The battery can have any suitable voltage rating such as a 12 volt DC battery. Alternatively, the circuit power source 420 can be an electrical device which draws current from the first power cable 240 and converts the current to a direct current of suitable voltage to safely operate the cutoff switch 400 when handle switch 195 is in a pressed down condition. The handle switch 195 can be any suitable switch such as a trigger switch 200. Any suitable trigger switch 200 can be used such as trigger switch part number 227798 manufactured or supplied by Miller Welder Parts available from PLC Center (A Division of Radwell International, Incorporated).
It should be appreciated that the embodiments of the present invention are not limited to those specifically described above. For instance, the apparatuses of the present invention may include different structures, features, or characteristics than those described above. Similarly, the methods of the present invention may include different operations, steps, or sequences than those described above. Therefore, it is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.
