Patent Publication Number: US-11638964-B2

Title: Welding tool and method of using a welding tool

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of U.S. patent application Ser. No. 16/372,311, entitled “Welding Tool and Method of Using a Welding Tool” and filed on Apr. 1, 2019, the entirety of which is hereby incorporated by reference. 
    
    
     FIELD OF THE DISCLOSURE 
     The present disclosure relates to a welding tool and to a method of using a welding tool. 
     BACKGROUND TO THE DISCLOSURE 
     Welding torches are used to weld together metal objects. When many welds are required, for example for large construction projects, it can be laborious and time consuming for a human to repetitively produce many welds of a consistently high quality. In addition, requiring a human to produce a large number of such welds may lead to mobility, health, and/or ergonomics issues. Although the ability to produce multiple welds of a consistently high quality has been automated to some extent, such automated devices are typically not easily portable, and the objects to be welded generally have to be brought to the welding device for welding. 
     SUMMARY OF THE DISCLOSURE 
     According to a first aspect of the disclosure, there is provided a welding tool comprising: a support structure; a welding torch coupled to the support structure and configured to rotate relative to the support structure about a welding axis; and a locating device coupled to the support structure and movable between a retracted position and an extended position in which the locating device extends toward the welding axis, wherein the locating device comprises a recess at an end thereof and is configured such that, when an object to be welded is positioned at least partially within the recess of the locating device in the extended position, the welding axis passes through the object to be welded. 
     Thus, with the welding tool described above, multiple welds surrounding anchor rods (or other suitable objects to be welded) may be rapidly and accurately produced. The welding tool may be operated by a labourer (a qualified welder is ideally not required). 
     The welding torch may be rotatably coupled to the support structure so as to rotate about the welding axis. 
     The recess may be sized and/or shaped such that, when the object to be welded is positioned at least partially within the recess of the locating device in the extended position, the welding axis passes through the object to be welded. 
     The recess may comprise a triangular shape. 
     The locating device may be configured to rotate between the retracted position and the extended position. The locating device may be further configured to translate toward and away from the welding axis. 
     The support structure may comprise one or more magnets for securing the welding tool to a work surface. The magnets may be provided in a base of the support structure. 
     An angle of the welding torch relative to the welding axis may be adjustable. 
     The support structure may comprise a base with a central aperture formed therein. In the extended position, the locating device may extend into the central aperture. 
     The locating device may comprise a first portion coupled to the support structure and a second portion extending at an angle (e.g. a non-horizontal angle) to the first portion, and the recess may be formed within the second portion. When the locating device is in the extended position, the second portion may extend through the central aperture. 
     The second portion may comprise a first member extending at an angle (e.g. a non-horizontal angle) to the first portion and a second member extending at an angle (e.g. a non-horizontal angle) to the first member. The recess may be formed within the second member. When the locating device is in the extended position, the second member may extend perpendicular to the welding axis. 
     The object to be welded may comprise an anchor rod. In some embodiments, the object to be welded may comprise any other suitable object, such as a circular plate. 
     The welding tool may further comprise a controller configured to implement a method comprising: activating the welding torch; rotating the welding tool about the welding axis; and deactivating the welding torch. For example, the controller may be communicatively coupled to the welding torch so as to cause the welding torch to activate and deactivate. The controller may furthermore control one or more motors or similar devices for causing the welding tool to rotate about the welding axis. For example, the motors may cause a rotatable element of the support structure, to which the welding tool is coupled, to rotate relative to the support structure. 
     The welding tool may be portable by a user. For example, it may be possible to relocate the welding tool manually, without the need for a hoist or lift. 
     According to further aspect of the disclosure, there is provided a welding tool comprising: a support structure; a welding torch coupled to the support structure and configured to rotate relative to the support structure about a welding axis; and a locating device coupled to the support structure and rotatable between a retracted position and an extended position in which the locating device extends toward the welding axis, wherein the locating device is configured such that, when an object to be welded is positioned in contact with an end of the locating device in the extended position, the welding axis passes through the object to be welded. 
     The welding tool may comprise any of the features described above in connection with the first aspect of the disclosure. 
     According to further aspect of the disclosure, there is provided a system comprising: any of the above-described welding tools; and a controller configured to implement a method comprising: activating the welding torch; rotating the welding torch about the welding axis; and deactivating the welding torch. The method may further comprise moving the locating device from the extended position to the retracted position prior to activating the welding torch. Moving the locating device from the extended position to the retracted position may comprise translating the locating device away from the welding axis and rotating the locating device relative to the support structure. 
     The method may further comprise moving the locating device from the retracted position to the extended position after deactivating the welding torch. For example, the controller may control one or more motors or similar devices for causing the locating device to move between the retracted position to the extended position. 
     The method may further comprise, prior to moving the locating device from the extended position to the retracted position, activating the one or more magnets comprised in the support structure. 
     The method may further comprise, prior to activating the welding tool, rotating the welding tool about the welding axis. 
     The controller may comprise: circuitry; or a processor communicative with memory having stored thereon computer program code configured when executed by the processor to cause the processor to implement the method. 
     The system may comprise any of the features described above in connection with the first aspect of the disclosure. 
     In a further aspect of the disclosure, there is provided a method of welding, comprising: providing any of the above-described welding tools; when the locating device is in the extended position, positioning the object to be welded in contact with the end of the locating device such that the welding axis passes through the object to be welded; moving the locating device to the retracted position; activating the welding torch; and rotating the welding torch about the welding axis so as to weld the object to be welded. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the disclosure will now be described in conjunction with the accompanying drawings of which: 
         FIG.  1    is a schematic diagram of a welding tool according to embodiments of the disclosure; 
         FIG.  2    is a view of an underside of the welding tool of  FIG.  1   ; 
         FIG.  3    shows a centering leg in an extended position, according to embodiments of the disclosure; 
         FIG.  4    shows the centering leg of  FIG.  3    in a retracted position; 
         FIG.  5    shows a welding tool according to embodiments of the disclosure; 
         FIG.  6    is a flow diagram of a method of using a welding tool, according to embodiments of the disclosure; 
         FIG.  7    shows schematic diagrams of different welds; 
         FIG.  8    shows an 8 mm fillet weld; 
         FIG.  9    shows a penetration profile of a weld; and 
         FIG.  10    shows a result of a pull test. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     The present disclosure seeks to provide an improved welding tool and method of using such a welding tool. While various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims. 
     The word “a” or “an” when used in conjunction with the term “comprising” or “including” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise. 
     The terms “coupled”, “coupling” or “connected” as used herein can have several different meanings depending on the context in which these terms are used. For example, the terms coupled, coupling, or connected can have a mechanical or electrical connotation. For example, as used herein, the terms coupled, coupling, or connected can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via an electrical element, electrical signal or a mechanical element depending on the particular context. The term “and/or” herein when used in association with a list of items means any one or more of the items comprising that list. 
     As used herein, a reference to “about” or “approximately” a number or to being “substantially” equal to a number means being within +/−10% of that number. 
     Generally, according to embodiments of the disclosure, there is described an automated welding tool. The welding tool includes a welding torch configured to rotate about a welding axis, and a locating device (which may also be referred to as a centering leg) used to position an object to be welded (which according to embodiments may be an anchor rod) on the welding axis. The welding tool may incorporate multiple bracing pillars on rubber feet to provide a stable structure that has sufficient weight to remain in place throughout rotation of the welding torch. At one end thereof, the centering leg includes a tailored recess or notch for properly aligning the anchor rod on the welding axis, thereby ensuring that the welding torch has a consistent line into the joint. 
     The welding torch may be provided at an adjustable angle and a pre-set elevation relative to the base of the support structure, and may be configured to rotate around the centre of the structure. The weld may be performed in one direction of rotation and then in the other, thus ensuring that no kinks arise in the welding cable that would result in wire feeding issues. After placement of the anchor rod into the recess of the centering leg, but prior to the welding sequence, the centering leg automatically retracts into an upright position to allow free rotation of the welding torch. 
     The figures will now be described in more detail. Turning to  FIG.  1   , and according to embodiments of the disclosure, welding tool  10  comprises a tool support structure  12  including a base  14 , an upper support  16 , and multiple bracing pillars  18  extending from base  14  to upper support  16 . A circular handle  20  extends upwardly from upper support  16 . Welding tool  10  further includes a welding torch  22  rotatably coupled to upper support  16  by means of a rotator  24  and a torch support  26 . Rotator  24  and torch support  26  are shown in more detail in  FIG.  2    which shows an underside of welding tool  10 . Rotator  24  is configured to allow welding torch  22  to rotate through 360 degrees about a welding axis W passing through the centre of welding tool  10 . Welding torch  22  comprises a torch body  28  joined to a welding cable  30  extending through a central aperture  32  formed within upper support  16 . As can be seen in  FIG.  2   , the underside of bracing pillars  18  include rubber feet  34 , and magnets  36  are provided within base  14 . 
     Welding tool  10  further includes a locating device, or centering leg  38 , shown in more detail in  FIGS.  3  and  4   . Centering leg  38  is rotatably coupled to tool support structure  12 . In particular, welding tool  10  includes an actuable arm  40  configured to move centering leg  38  between an extended position and an upright, retracted position. The extended position of centering leg  38  can be seen in more detail in  FIG.  3   , and the retracted positon of centering leg  38  can be seen in more detail in  FIG.  4   . Centering leg  38  includes a first portion  42  rotatably attached to base  14 , and a second portion  44  rotatable relative to first portion  42 . Second portion  44  includes an angled extension  46  extending away from first portion  42  at a downward angle thereto, and an end portion  48  extending away from angled extension  46  at an angle thereto. End portion  48  is substantially parallel to first portion  42 . In the extended position, centering leg  38  extends through a central aperture  50  formed within base  14 . 
     End portion  48  of centering leg  38  includes a recess or notch  52  formed therein. Notch  52  comprises generally a triangular shape at the end of centering leg  38 , although the skilled person will recognize that the disclosure extends to recesses having other suitable shapes. Notch  52  is sized such that, when an anchor rod  54  is positioned within notch  52  and in contact with the sides of notch  52 , welding axis W passes through the centre of anchor rod  54 . 
     Turning to  FIG.  5    which shows welding tool  10  according to embodiments of the disclosure, welding tool  10  includes a controller  56  for controlling operation of welding tool  10 . In particular, controller  56  includes circuitry configured to enable welding tool  10  to perform various actions. For example, controller  56  may activate magnets  36  in order for welding tool  10  to be secured to a metallic work surface  58  ( FIGS.  3  and  4   ). Controller  56  may additionally control the extension and retraction of centering leg  38 , as well as the rotation of rotator  24  relative to upper support  16 . Furthermore, controller  56  may control activation and deactivation of welding torch  22 . In some embodiments, instead of or in addition to circuitry, controller  56  may comprise a processor communicative with memory having stored thereon computer program code configured, when executed by the processor, to cause the processor to implement one or more of the above functions. Further still, in some embodiments controller  56  may be provided independently of welding tool  10 , and controller  56  may be configured for example to control welding tool  10  remotely. 
     Turning to  FIG.  6   , according to embodiments of the disclosure there is shown a method  60  of performing welding, using welding tool  10 . Centering leg  38  is initially in the extended position. At block  61 , welding tool  10  is positioned over the anchor rod  54  to be welded. In particular, anchor rod  54  is located within notch  52  of centering leg  38  and is positioned in contact with the sides of notch  52 . At block  62 , a user uses controller  56  to activate magnets  36 . Once magnets  36  are activated, at block  63 , the user may then push downwardly on welding tool  10 , using handle  20 . Through the downward force applied to welding tool  10 , rubber feet  34  compress and magnets  36  approach metal work surface  58  until welding tool  10  is securely engaged to work surface  58 . Controller  56  is then used to initiate a welding sequence, as follows. In particular, at block  64 , controller actuates arm  40  to rotate centering leg  38  into the retracted position. At block  65 , controller  56  activates welding torch  22 . At block  66 , controller  56  rotates welding torch  22  to form the joint between anchor rod  54  and work surface  58 . In some embodiments, welding torch  22  is rotated through an angle of greater than 360 degrees (in some embodiments, 368 degrees). This enables the start of the weld to be filled. At block  67 , controller  56  deactivates welding torch  22 . Rotator  24  may then rotate welding torch  22  back to its original position, to ensure that no kinks develop in welding cable  30 . At block  68 , controller  56  actuates arm  40  to rotate centering leg  38  into the extended position, for subsequent welding. 
     In some embodiments, a user may use controller  56  to rotate welding torch  22  a predetermined amount, for example prior to welding. This allows a user to determine the point at which welding torch  22  begins welding. 
     Experimental Results 
     Three different welds were initially considered, as set out below and as shown in  FIG.  7   .
         1. ⅜″ [10 mm] fillet weld (Type-A);   2. 5/16″ [8 mm] fillet weld (Type-B); and   3. ¼″ [6 mm] fillet weld (Type-C).       

     Three separate specimens were originally considered for three test types (a total of nine tests) using a ⅜″ all-around fillet weld (Type A), a 5/16″ fillet weld (Type B) and a ¼″ fillet weld (Type C) for the anchor rod to plate connection. A heavy, 2″ plate was used to simulate the concrete-filled core backing the shell plate. 
     Testing was run to failure, with all Type A and Type B specimens exhibiting yielding to fracture failure, while two of three Type C connections exhibited the same failure behavior. One Type C (¼″ weld) had the weld fracture and rod pull through the plate. This was a result of both minimum weld material and heat input. In summary, the 6 mm (¼″) fillet weld was of adequate size to satisfy the structural requirements of the anchor rod fillet weld, but given the travel speed during welding necessary to generate the smaller fillet weld size, it is unrealistic to 
                     TABLE 1                  Welding parameters for test samples and process/consumable information.                                         Sample   Wire Feed Speed   Voltage   Travel           Wire Dia.       #   m/min [ipm]   V   Setting   Process   Wire   mm                                                 1   7.62 [300]   32   25   MCAW   E491C-6MJ-H4   1.6                           E70C-6M-H4       2   7.62 [300]   32   25   MCAW   E491C-6MJ-H4   1.6                           E70C-6M-H4       3   7.62 [300]   32   25   MCAW   E491C-6MJ-H4   1.6                           E70C-6M-H4       4   7.62 [300]   32   25   MCAW   E491C-6MJ-H4   1.6                           E70C-6M-H4       5   8.89 [350]   28   18/19   FCAW   E491T-9MJ-H8   1.6                           E71T-9M-JH8       13   8.89 [350]   28   18/19   FCAW   E491T-9MJ-H8   1.6                           E71T-9M-JH8       15   8.89 [350]   28   18/19   FCAW   E491T-9MJ-H8   1.6                           E71T-9M-JH8       18   8.89 [350]   28   18/19   FCAW   E491T-9MJ-H8   1.6                           E71T-9M-JH8                    
produce consistent penetration profiles at these speeds.
 
     The 8 mm ( 5/16″) fillet option provides an improved compromise between welding efficiency and a consistent weld that meets the structural requirements. A manually welded 8 mm fillet weld underwent mechanical testing, showing that the failure upon tensile testing occurs within the anchor rod, exhibiting a traditional necking to failure mechanism. An example of the 8 mm fillet weld produced by the welding tool can be seen in  FIG.  8   . 
     Eight rod specimens welded using the automated welding tool were completed, four using metal-cored arc welding (MCAW) and another four using flux-cored arc welding (FCAW). The welding parameters and information regarding the consumables and welding processes for the test samples are shown in Table 1. 
       FIG.  8    shows a representative example of a weld produced using the automated welding tool. The use of the 1.6 mm electrode allowed for increased welding efficiency and increased the current level as compared to the 1.3 mm wire which in turn led to a deeper penetration profile. The deeper penetration profile can be seen in  FIG.  9   . It was observed that for welds with insufficient penetration profiles, the failure mode of the anchor rod specimens still occurred within the rod, but occurred at the top of the anchor rod, in close proximity to the weld. 
     In four pull tests on the rod setup with both metal-cored arc welding MCAW and flux-cored arc welding FCAW, in all cases the failure occurred in the rod and the weld remained unaffected. These results clearly show that the 8 mm fillet weld generated with the automated welding tool is robust and consistent. An example of the pull test results is shown in  FIG.  10   . 
     Based on the results of tension testing and the consistency of the welds produced, the automated welding tool has been shown to provide a satisfactory weldment, particularly with the MCAW process. The use of the 1.6 mm consumable allowed for a significant (˜50%) reduction in the welding time for one anchor rod. The deep penetration profile and consistent outer weld profile indicate that this process can effectively provide reliable results. 
     While the disclosure has been described in connection with specific embodiments, it is to be understood that the disclosure is not limited to these embodiments, and that alterations, modifications, and variations of these embodiments may be carried out by the skilled person without departing from the scope of the disclosure. It is furthermore contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.