WO2024075087A1

WO2024075087A1 - Working assemblies and welding apparatuses comprising same (vgs i & ii)

Info

Publication number: WO2024075087A1
Application number: PCT/IB2023/060100
Authority: WO
Inventors: Hon Wing YEE
Original assignee: Build King Civil Engineering Limited
Priority date: 2022-10-07
Filing date: 2023-10-09
Publication date: 2024-04-11

Abstract

A working assembly of a welding apparatus including a head portion, an arm portion which provides mechanical support to the head such that the head portion is movable relative to the arm portion to change its elevation is disclosed. The working assembly comprises a surface tracking mechanism which is configured to maintain a preset separation distance between a welding head and a target location to facilitate continuous automated welding.

Description

WORKING ASSEMBLIES AND WELDING APPARATUSES COMPRISING SAME (VGS I & II)

FIELD

[01] The present disclosure relates to working assemblies of welding apparatuses, and to welding apparatuses comprising working assemblies.

BA CKGROUND

[02] A welding apparatus typically comprises a working assembly which comprises an arm portion and a head portion. The head portion comprises a welding head which is configured to feed a welding-facilitating medium to a target location at which a weld is to be formed, and the arm portion is configured to facilitate positioning of the welding head so that the welding head is aimed at the target location when welding is being performed.

[03] Welding works involve highly repetitive operations at high temperatures and are hazardous. Therefore, working assembly of welding apparatus that can facilitate performance of welding works with a high degree of automation are desirable.

SUMMARY

[04] Working assembles of welding apparatuses and welding apparatuses configured to facilitate performance of welding work, especially automated welding work, are disclosed.

Working assembly

[01] A working assembly of a welding apparatus is disclosed.

[02] The working assembly comprises an arm portion and a head portion. The head portion includes a working head which is configured to facilitate performance of welding work on a target location. The working head is mechanically supported by the arm portion and is movable relative to the arm portion between a first relative position and a second relative position, the first relative position being an un-extended position corresponding to a first elevation level relative to the arm portion and the second relative position being an extended position corresponding to a second elevation level relative to the arm portion.

[03] The working assembly comprises a spacing tracking mechanism which is configured to follow or track surface profile of a surface and to move the head portion relative to the arm portion to adjust its relative elevation level with respect to the arm portion according to the surface profile so that the working head is at a preset separation distance from a target location. [05] The working head comprises or is configured to hold a welding head, and the welding head may be permanently or releasably held.

[06] The welding head may comprise a nozzle portion which comprises a welding nozzle configured to feed a welding-facilitating medium to a target location when welding is to be performed at the target location. The welding nozzle may comprise a wire-feeding nozzle which is configured to feed a wire filler to a location to be welded, which is referred to as a target location. The feeding nozzle may include an electrode nozzle through which a welding electrode protrudes. The welding nozzle may include a gas nozzle which is configured to feed a gas, for example, an inert gas, to the target location while welding is being performed to mitigate contamination such as oxidation. The gas nozzle may surround or in juxtaposition with the electrode nozzle.

[07] To prepare the working assembly for performance of welding operation on a target location, the working assembly is brought into a ready position at which the welding nozzle and the target location are in alignment and in proximity. When the welding nozzle and the target location are in alignment, the welding nozzle is aimed at the target location so that a welding medium which is fed from the electrode nozzle will be in close proximity or in abutment with the target location. The welding medium may be a welding electrode or a welding medium.

[08] After the working assembly is at the ready position, a welding voltage is applied to the working head, and the applied voltage will result in the formation of an arc and an arc current passing through the welding wire. As a result of the arc or the arc current, the portion of welding wire which is in abutment or in close proximity with the target location will be melted and a weld will be formed at the target location. To perform welding with unhindered inert gas supply, the gas nozzle is preferably kept at a separation distance away from the welding location.

[09] The working assembly is configurable to operate in a plurality of states, including a first state which is an un-extended state, a second state which is an extended state, and a third state which is a neutral state.

[10] The working assembly is configured to facilitate automated welding and may include an arrangement which is configured so that the separation distance between the working head and a target location will be at a pre-set value when the working assembly is aligned with the target location. The separation distance may be measured with respect to a forward end of a reference part, for example, the forward end of a functional part such as the inert gas nozzle. The preset value may be a separation distance of say between 10-12cm between the working head or the functional part and the target location, with a tolerance of say ±1mm, ±1.5mm, ±2mm, ±2.5 mm or ±3mm, or a range or ranges formed by combining any of the aforesaid values. [11] The working assembly may comprise a surface-profile tracker which is configured to track or follow the profile of a surface, which is taken as a reference surface, and to set a separation distance between the working head and a target location with reference to the reference surface.

[12] The reference surface may be a surface which is underneath the working assembly so that the reference surface and the target location are in proximity.

[13] The reference surface may be a surface which leads to a target location, which is ahead of the target location, or which includes or surrounds the target location.

[14] The target location may be at an elevation level which is different from the elevation level of the reference surface, and the elevation level of the working head with respect to the reference surface may be set to take into account the difference in elevation levels.

[15] The working head may be set at an elevation level, taken into account the required separation distance and an off-set due to the difference in elevation levels.

[16] For example, the working head or a functional part thereof may be set at an offset elevation amplitude with respect to a reference elevation level, which may be the elevation level of a reference surface.

[17] The working assembly is configured to form a weld. A weld may be formed when two things are joined to form a welded assembly by welding along their corresponding edges. A welded surface is typically formed when two surfaces are joined along their corresponding edges, and the welded surface includes the weld.

[18] A weld may be formed by discrete or continuous welding. A weld or a welded surface formed by discrete welding includes a plurality of welded joints and immediately adjacent welded joints are at a separation distance apart. A weld or welded surface formed by continuous welding includes a plurality of welded joints and immediately adjacent welded joints are in abutment or in contiguity.

[19] Where a welded assembly is configured to provide passage for or to prevent ingress of fluid, liquid or fine particles such as dusts, the welded assembly is typically formed by continuous welding.

[20] The working assembly may be configured to work to form a curved weld. A curved weld may be formed, for example, when two curved things, for example, tubes, pipes, ducts or tunnel portions, are joined by welding their corresponding curved edges to form a welded assembly. The curved weld joins two adjacent curved surfaces to form a curved welded surface which extends along a curved path. The curved surfaces may be the internal and/or external curved surfaces of the curved things. [21] Where the working assembly is to perform welding to form a curved welded surface, welding will be performed at a plurality of locations which are target locations that are distributed along a curve path and have different elevation levels.

[22] Where welding is to be performed at locations having different elevation amplitudes, the working assembly may comprise an adjustment mechanism which is configured to adjust the elevation level of the working head so that a preset separation distance can be kept or maintained between the working head and a target location to be welded.

[23] The working assembly may be configured for working on a curved surface in which case the separation distance may be set with reference to the curving characteristics of the curved surface.

[24] For example, where a weld is to be formed along a curved path having a constant curvature or a flat surface, for example, a circular path, the working assembly may be configured such that the working head is set at an elevation level with respect to a reference surface. The reference surface may be provided by a surface tracker so that deviation from the constant curvature can be compensated by surface tracking.

[25] The working assembly may comprise a surface-tracking mechanism which is configured to track the elevation of a reference surface.

[26] The working assembly may comprise a separation-tracking mechanism which is configured to set the separation distance between a target location and the working head with reference to the elevation of a reference surface.

[27] The working assembly may comprise a separation-following mechanism which is configured to track a surface and to adjust separation distance between the working head and the surface being tracked to maintain a preset separation distance between the working head and a target location.

[28] The working assembly may be configured to perform remote and/or automated welding. Automated welding is desirable, for example, when welding work needs to be performed inside a confined space such as inside a pipe, duct, tunnel or like environments. Automated herein means that welding work is performed by machine operated manoeuvring of the working assembly and/or the working head.

[29] To facilitate remote and/or automated welding, the working assembly may comprise a remote viewer. The remote viewer may comprise an image capture device such as a camera lens, which is configured to continuously capture real-time images of the target location, for example, before, during and/or after each welding, and to send captured images to a remote station whereby operation can be confirmed and/or welding result can be verified. [30] The working assembly may comprise peripheral devices such as a power interface which is configured to supply electric power to facilitate welding operation, a welding-medium interface which is configured to receive consumables such as welding wire and inert gas, a signal interface which is configured to transmit video signals out of the working assembly, and/or other interfaces without loss of generality.

[31] The working assembly is configured to be part of a welding apparatus which comprises the working assembly and a carrier which is configured to provide support to the working assembly. The support provided by the carrier may include mechanical support and operation support such as mobility, material, power and/or other support.

Welding apparatus

[32] A welding apparatus configured to perform automated welding comprises a working assembly of the present disclosure and a carrier.

[33] The carrier may be a carriage which is configured to provide mobility to the working assembly. The welding apparatus may be configured so that automated welding operations can be performed while the working assembly is in motion. When a welding apparatus is configured to perform welding operation continuously while in motion, a train of welds will be formed and this train will comprise a plurality of welded joints, and adjacent welded joints may be in abutment or in contiguity.

[34] The mobility may be provided by having the working assembly fixedly attached to the carriage so that the working assembly is to move in synchronization with the carriage.

[35] The mobility may be provided by having the working assembly movably attached to the carriage so that the working assembly is movable relative to the carriage and the working head is movable relative to the working assembly.

[36] The arm portion may include a mechanical arm. The mechanical arm may have an arm axis and the working head may be movable in a direction parallel to the arm axis between an un-extended position and an extended position.

[37] The mechanical arm may be elongate and the arm axis may be a longitudinal axis which a longitudinal direction.

[38] The mechanical arm may be movably attached to the carriage so that the working head may be moved by the mechanical arm to reach a plurality of target locations to perform welding while the carriage remains at a parked position.

[39] The mechanical arm may be rotatably attached to the carriage so that the working head may be rotated by the mechanical arm to reach a plurality of target locations to perform welding while the carriage remains at a parked position. FIGURES

[04] The subject matter of the present disclosure is further described by way of example, and with reference the accompanying figures, in which:

[05] Figures 1A, 1 B, 1C are various views of an example welding apparatus according to the present disclosure,

[06] Figures 1 D, 1 E, 1 F, 1G, 1 H, are various views of a working assembly of the welding apparatus of Figure 1A, and

[07] Figures 2A, 2B, 2C and 2D are various views of a working assembly of a welding apparatus,

[08] Figures 3A and 3B are end views of an example welding apparatus comprising a working assembly of Figure 2A,

[09] Figures 4A, 4B, 4C, 4D and 4E are schematic or conceptual views showing various functional aspects of a working assembly, and

[10] Figures 5A and 5B are schematic views showing various functional aspects of a welding apparatus comprising a working assembly of Figure 4A.

DESCRIPTION

VGS Mark I

[40] Referring to Figures 1A, 1 B, 1C, 1 D, 1 E, 1 F, 1G, 1 H, a working assembly 10 comprises an arm portion 120 including a mechanical arm 122 and a head portion 140 including a working head. The working head comprises a retention device which includes a clamping device 142. The retention device is configured for releasably holding a welding head 144 so that the welding head is at a selected relative elevation level and at a selected relative angle. The welding head 144 is a forward end of a welding gun, which may be a staple welding gun comprising a welding nozzle and a flexible supply tube which is configured to supply welding wire and inert gas to the welding nozzle.

[41] The head portion is movably connected to the mechanical arm 122 and that the head portion is movable relative to mechanical arm 122 between a first relative position and a second relative portion.

[42] The head portion is movably connected to the mechanical arm 122 by a support structure. The support structure comprises a rigid member 134 which provides mechanical support to the head portion including the clamping device 142. The rigid member 134 is elongate and includes a first end and a second end which are longitudinal ends. The rigid member 134 cooperates with the mechanical arm 122 to form a telescopic assembly having a telescopic axis T-T’ and the rigid member 134 is movable relative to the mechanical arm in a telescopic direction along the telescopic axis between a first relative position and a second relative portion.

[43] The retention device including the clamping device 142 is mechanically connected to the rigid member 134 by means of an intermediate structure 130 which is a bridging structure and the rigid member 134 provides mechanical support to the head portion including the clamping device 142 via the intermediate structure. The intermediate structure extends in a generally transversal direction to the telescopic axis and the head portion overhangs the rigid member 134 and the mechanical arm 122. The intermediate structure is configured to follow the telescopic movements of the rigid member 134 so that the clamping device 142 also follows the telescopic movements of the rigid member 134.

[44] The surface tracking mechanism comprises a surface tracker including a contact sensor which is configured as to track and follow the surface profile of a surface in contact with the surface tracker.

[45] The surface tracker 152 is on a longitudinal end of the rigid member 134 and is configured to provide mechanical support to the rigid member 134, as well as to the head portion, which is mechanically supported by the rigid member 134. The surface tracker is configured to track and follow the surface profile of a surface so that the instantaneous elevation level of the surface tracker follows the instantaneous elevation level of the tracked surface. The surface tracker 152 comprises a wheel which is configured to confer mobility to the working assembly.

[46] The intermediate structure joins the rigid member 134 at a location that is intermediate its longitudinal ends and projects away therefrom to join the head portion 140.

[47] The surface tracker and the intermediate structure are fixedly connected to the rigid member 134 so that the intermediate structure, and therefore the head portion connected thereto, also follows the surface profile of a surface and their instantaneous elevation levels are to change according to the surface profile of the tracked surface.

[48] The telescopic assembly comprising the rigid member 134 and the mechanical arm 122 is configurable between an un-extended state and an extended state. The assembly has a first length when in the un-extended state and a second length when in the extended state, such that the second length is larger than the first length. [49] The rigid member 134 is movable relative to the mechanical arm 122 along a telescopic axis which defines the length of the assembly. The telescopic axis is a centre axis which is coaxial with the arm axis of the mechanical arm and centre axis of the rigid member 134.

[50] The telescopic assembly is under spring bias to extend to its extended state which is an expanded state, at which the length of the telescopic assembly is at its maximum.

[51] The telescopic assembly may be compressed against spring bias to shorten to its unextended state, which is a contracted state, at which the length of the telescopic assembly is at its minimum.

[52] Therefore, the telescopic assembly can have a range of length including a variation in length which is the difference between its maximum and minimum lengths. The variation in length is 2.5 cm, but can be set to be higher or lower according to the anticipated surface profile characteristics of a surface to be worked on.

[53] The mechanical arm 122 is configured as a cylinder and the rigid member 134 is configured to form a compatible piston which is slidably movable inside the steel cylinder and along a cylinder axis which is coaxial with the mechanical arm axis.

[54] The mechanical arm 122 has a length of about 15cm, which is the minimum length of the assembly.

[55] The mechanical arm 122 has a square cross-section and each outer side has a width of about 5.5cm.

[56] The mechanical arm 122 has a peripheral wall which defines an internal chamber of the cylinder and an elongate aperture is formed on one side of the peripheral wall to allow passage of a bridging portion of the bridging structure and facilitates interconnection between the rigid member 134 and the bridging structure.

[57] The surface tracker is formed on a telescopic end of the telescopic assembly. More specifically, the surface tracker is formed on an exposed end of the rigid member 134, which is a support member configured to provide mechanical support to the head portion.

[58] To prepare for welding operations, a welding gun having a welding head is attached to working assembly and retained by the retention device. The retention device of the working assembly is configured as an adjustable clamp.

[59] The welding gun is clamped so that its welding head is at an elevation level relative to the surface tracker. The elevation level of the welding head relative to the elevation level of the surface tracker is set to achieve preferred welding conditions having taken into account the anticipated surface profile of a surface to be worked. [60] The welding gun may be set at an aiming angle to aim at a target location by adjusting the retention device so that the welding nozzle is aligned with a target location.

[61] The working assembly is configured to be a part of a welding apparatus and comprises a coupling arrangement 136 for making mechanical coupling with a carrier. The coupling arrangement 136 is fixedly attached to the mechanical arm 122, for example, by welding, and functions as a rigid linkage to interconnect the working assembly and the carrier so that the mechanical arm is fixedly connected with the carrier.

[62] Referring to Figures 1A, 1 B and 1 C, a welding apparatus comprises a carrier comprising a carriage 1000 and a working assembly 10. The working assembly 10 and the carriage 1000 are connected side-by-side by a rigid linkage 1010. The linkage 1010 comprises a rigid bar which is integrally formed with the rigid member 134 and extends transversely therefrom.

[63] The linkage 1010 extends transversely to the intermediate structure such that the linkage 1010, the intermediate structure, and the telescopic axis are on three mutually orthogonal directions.

[64] The carriage comprises mobility means 1020 which are configured to move in a travel direction that is orthogonal to the linkage 1010 and the telescopic axis. Orthogonal herein includes substantially orthogonal, and may mean a deviation of say ±5° or ±10° from right angle. The surface tracker 152 and the mobility means 1020 are configured to travel in the same direction, and the working head is to approach a target location by forward or backward movement of the carriage.

[65] The carriage 1000 is configured to provide mechanical support to the working assembly so that the working assembly can perform welding work with adequate stability. The carriage may be configured as a ballast insofar as the working assembly is concerned, so that the weight of the working assembly can be entirely supported by the carriage when the surface tracker is not in contact with a support surface. The carriage may include power conversion circuitry on board so that it can provide operational power to the working assembly and at the same time has sufficient weight to provide stability.

[66] In operation, the working assembly is carried by a carriage which is configured to exert a downward force to urge the surface tracker 152 to press against a contact surface. When the working assembly and the carriage are so configured, the working assembly is in an intermediate state which is between the expanded state and the contracted state. With such an interconnection, the rigid member can move to lengthen or shorten the working assembly when there is a difference in elevation levels between the carriage and the surface tracker, so that the working head can always operate at a preset separation difference between the working head and a target location. [67] The surface tracker 152 is a non-deformable tracker so that when the surface tracker 152 is urged to press against a contact surface during welding operations, a constant relative elevation is maintained between the welding head and the contact surface to facilitate preferred welding. Elevation herein is measured in a direction parallel to the telescopic axis.

[68] The working assembly may be attached to a carriage by means of an attachment mechanism. The attachment mechanism may be configurable so that the elevation offset between the surface tracker and the carriage can be adjusted.

[69] The working assembly 10 comprises an attachment which is welded onto the mechanical arm and is configured to attach to one side of the carriage so that the carriage and the working assembly are to move together in a side-by-side manner, and the working head can be ahead of or trailing behind the mechanical arm 122 during welding operations.

[70] The working assembly may be configured to move relative to the carriage while attached thereto. For example, the carriage may comprise a track, for example, on a side so that the working assembly can move or translate along the track and relative to the carriage and to perform welding at a plurality of target locations, for example, while moving relative to the carriage.

[71] In example embodiments, the working assembly may be rotatably attached to the carriage so that the working assembly can perform welding at a plurality of target locations while in rotational.

VGS Mark II

[72] A working assembly of the present disclosure comprises an arm portion and head portion which are movably connected. The head portion comprises a working head which is configured to perform welding and the arm portion provides mechanical support to the head portion. The working head comprises a welding head which is configured to be in alignment with a target location during welding operation. A target location herein is a location at which a welded joint is to be formed by welding.

[73] The working assembly comprises a spacing mechanism which is configured to set a separation distance between the head portion and a reference surface. The spacing mechanism comprises a surface tracking mechanism and a movement mechanism. The movement mechanism is configured to drive the head portion to move relative to the arm portion, and the surface tracking mechanism is configured to track a target surface and to provide surface-tracking information to a controller so that the controller can operate the movement mechanism to move the head portion relative to the arm portion so that the head portion and the reference surface is at a preset separation distance when welding work is to begin and/or when welding work is in progress. [74] The head portion comprises a first portion which is in abutment with the arm portion and a second portion which comprises the working head. The first portion is elongate and extends along a longitudinal direction between a first longitudinal end and a second longitudinal end. The head portion and the arm portion are mechanically connected such that its first longitudinal end always remains on the arm portion while its second longitudinal end is configured to project beyond the arm portion during welding operations. The longitudinal direction is defined by a longitudinal axis which is a centre axis of the first portion. The centre axis of the first portion is parallel to and offset from the arm axis. The second portion is proximal the second longitudinal end of the first portion and the working head overhangs the first portion.

[75] The arm portion may comprise a mechanical arm which is elongate and extends along an arm axis. The arm axis is a centre axis which defines a longitudinal axis and a longitudinal direction of the mechanical arm. The mechanical arm is to provide mechanical support to the head portion and the head portion is movable relative to the mechanical arm between a first position which is an un-extended position and a second position which is an extended position.

[76] The mechanical arm may be configured as a guide rail along which the head portion is movable between the un-extended position and the extended position. The guide rail has a rail axis which is parallel to the arm axis so that the guide rail defines a movement direction that is parallel to the arm axis.

[77] The head portion may be configured such that its first portion is a coupling portion that is always in mechanical coupling and in mechanical abutment with the mechanical arm.

[78] The coupling portion may comprise a rail follower so that movement of the head portion relative to the arm portion always follows a movement direction which is the direction of the guide rail as defined by the rail axis due to cooperation between the rail guide and rail follower.

[79] The coupling portion may be configured to cooperate with the mechanical arm to form a compartment for receiving parts, components and circuitry of the spacing mechanism. The parts, components and circuitry may include a motor, a drive train, motion connection components which interconnect the coupling portion, the mechanical arm, the motor, and/or the drive train, and the controller and peripheral circuits and electronic components.

[80] The mechanical arm may include a steel structure so that it has a sufficient strength to provide mechanical support to the head portion to facilitate performance of continuous welding operations. The coupling portion may include a steel structure so that it has a sufficient strength to provide mechanical support to the second portion of the head portion.

[81] The welding head may comprise a welding nozzle which is configured to feed a weldingfacilitating medium to a target location when welding is to be performed at the target location. The welding nozzle may comprise a wire-feeding nozzle which is configured to feed a wire filler to a location to be welded, which is referred to as a target location.

[82] The feeding nozzle may include an electrode nozzle through which a welding electrode protrudes. The welding nozzle may include a gas nozzle which is configured to feed a gas, for example, an inert gas, to the target location while welding is being performed to mitigate contamination such as oxidation. The gas nozzle may surround the wire-feeding nozzle and both may be set to aim at the target location. The gas nozzle and the wire-feeding nozzle may be coaxial and/or flush.

[83] The welding head may be configured such that the welding nozzle is at a preset separation distance from a target location when welding is to begin and while welding is in progress. The preset separation distance may be selected to facilitate feeding of weldingfacilitating medium accurately towards the target location. For example, where a weld wire is to be fed, the separation distance would need to take into account the rigidity and/or curving of the weld wire. The preset separation distance may be selected to facilitate feeding of inert gas accurately towards the target location while mitigating pre-mature blocking of the inert gas nozzle due to weld splattering. An example separation distance which is found to be preferred is about 10mm-12mm.

[84] To facilitate setting and maintenance of the separation distance, the spacing mechanism is provided. The surface tracking mechanism may comprise a surface-separation sensor and the surface sensor may be mounted so that its sensing surface is on a longitudinal end of the coupling portion that is distal from the mechanical arm.

[85] The working assembly may comprise an image capture device which is configured to capture real-time images of the target location. An image capture device may comprise one or more lenses which are in connection with an image processing arrangement for converting optical images to electrical signals. The electrical signals may be transmitted out of the working assembly for remote monitoring and control.

[86] Referring to Figures 2A, 2B, 2C and 2D, an example working assembly 20 is shown. The working assembly 20 comprises an arm portion 220 and head portion 240 which is movably connected to the arm portion 220.

[87] The head portion 240 comprises a working head 242 which is configured to perform welding and the arm portion 220 provides mechanical support to the head portion. The working head 242 comprises a welding head 242A which is configured to be in alignment with a target location during welding operation. The arm portion 220 provides mechanical support to the head portion 240 and includes a mechanical arm 222. The mechanical arm 222 is elongate and extends along an arm axis X-X’ which is a centre axis defining a longitudinal axis and a longitudinal direction of the mechanical arm 222.

[88] The head portion 240 includes a first portion 240A and a second portion 240B. The first portion 240A is in abutment with the mechanical arm 222, the second portion 240B comprises the working head 242, and the first portion 240A is intermediate the second portion 240B and the mechanical arm 222. The first portion 240A is elongate and extends along a longitudinal direction between a first longitudinal end and a second longitudinal end.

[89] The arm portion 220 and the head portion 240 are mechanically connected such that the first longitudinal end of the first portion 240A always remains on the arm portion 120 while the second longitudinal end of the first portion 240A is configured to project beyond the arm portion during welding operations. The longitudinal direction of the first portion 240A is defined by a longitudinal axis X-X’ which is a centre axis of the first portion. The centre axis of the first portion is parallel to and offset from the arm axis.

[90] The second portion 240B is proximal the second longitudinal end of the first portion 240A and includes a hood portion 244 which extends in a transverse direction to project away from and overhang the first portion 240A so that the first portion 240A is intermediate the hood portion 244 and the arm portion 220.

[91] The welding head 242A is suspended from the hood portion 244 and is arranged to project in a projection direction to aim at a location corresponding to a target location. The target location may be on or near an intersection between a line of projection of the working head and a longitudinal extension of the first portion 240A.

[92] An image capture device is also suspended from the hood portion 244 and aligned to aim at the target location. The working assembly comprises a surface-separation sensor 246. The surface-separation sensor 246 has a surface-sensing surface which is on or near the second longitudinal end of the first portion 240A and is configured to sense the proximity of a surface which is on a longitudinal extension of the first portion 240A. A staple LJ18A3 type of proximity sensor may be used as a surface-separation sensor. The output of the proximity sensor is connected to a control circuit which is configured to operate a movement mechanism to maintain a preset separation distance.

[93] The working head 242 is movable relative to the arm portion 220 between a first position which is an un-extended position and a second position which is an extended position. The first position and the second positions are end positions of the working head with respect to the arm portion 220. The working head 242 is closest to the arm portion 220 when in the first position and furthest from the arm portion 220 when in the second position. [94] The working assembly comprises a movement mechanism which is configured to move the head portion 242 relative to the arm portion 220. Parts, components and circuitry of the spacing mechanism are received inside a compartment formed by cooperation of the first portion 240A and the arm portion 220. The movement mechanism provides mechanical drive interconnection between the arm portion 220 and the head portion 242 to facilitate relative movement therebetween.

[95] The first portion 240A is part of a rigid structure which cooperates with the mechanical arm 222 to form a telescopic assembly having a telescopic axis, and the rigid structure is movable relative to the mechanical arm along a telescope axis which defines a telescopic direction.

[96] The assembly comprising the first portion 240A and the mechanical arm 222 is configurable between a first state which is an un-extended state and a second state which is an extended state. The assembly has a first length when in the un-extended state and a second length when in the extended state. The length of the assembly is measured along a longitudinal axis which defines a longitudinal direction, and the second length is larger than the first length.

[97] The mechanical arm 222 provides mechanical support to the rigid structure so that the welding head 242A can move relative to the mechanical arm 222 to perform welding operations. The drive mechanism includes a motor, a drive train driven by the motor and a control circuit which is to control the motor. The drive train interconnects the arm portion and the head portion so that the head portion is movable away from the arm portion to extend the working assembly to the extended state and towards the arm portion to contract the working assembly to the un-extended state.

[98] A passageway is formed on the arm portion to provide passage for the welding wire, the inert gas and the video signals of the captured images. The passageway is part of a mechanical arrangement which is configured to interconnect the working assembly and a carrier.

[99] A welding apparatus comprising a working assembly 20 which is rotatably mounted on a carriage 2000 is depicted in Figures 3A and 3B.

[100] The carrier is configured as a base station to provide mechanical and operational support to the working assembly so that the working assembly can perform welding operations while supported by the carrier.

[101] The carrier may be configured to provide mobility to the working assembly so that the working assembly can perform welding operations whilst in motion. [102] For example, the carrier may be a carriage which is configured to move relative to a support surface and the working assembly may be fixedly attached to the carrier so that the working assembly is to move together with the carrier and to perform welding while the carrier is in motion.

[103] The working assembly may be movably mounted on the carrier so that the working assembly can perform welding operations while moving relative to the carrier. For example, the working assembly may be retained in the same orientation with respect to the carrier and to perform welding while the carrier is moving.

[104] For example, the working assembly may be rotatably mounted on the carrier so that welding work can be performed by the working assembly while the working assembly is in rotation relative to the carrier.

[105] The head portion is movably connected to the arm portion so that the working head can move away or move towards the mechanical arm. The working assembly may be configured such that when the working head is moved away from the mechanical arm, the working assembly is elongated and in an extended state, and when the working head is moved towards the mechanical arm, the working assembly is shortened and in a shortened state.

[106] When the working assembly is so configured, the separation distance between the welding nozzle and a target location can be changed or adjusted. This configuration facilitates setting of a preferred or desired separation distance between the welding nozzle and a target location, for example, according to characteristics of the welding medium, characteristics of the target to be welded, etc.

[107] The working head and the mechanical arm may be connected by a resilient biasing means and has a neutral state, which may be a spring-neutral state. The resilient biasing means is configured to urge the working assembly to return to the neutral state when elongated or shortened.

[108] The working head and the working assembly may be in corresponding states, such that when the working assembly is in the un-extended state, the working head is in an un-extended state and at an un-extended position relative to the mechanical arm; when the working assembly is in the extended state, the working head is in an extended state and at an extended position relative to the mechanical arm; and when the working assembly is in the neutral state, the working head is in neutral state and at neutral position relative to the mechanical arm, the neutral position being intermediate the un-extended position and the extended position.

[109] Referring to Figures 4A to 4D, an example working assembly comprises an arm portion and a head portion. The arm portion including a mechanical arm comprising an upper plate member 122A, a lower plate member 122B, and a plurality of stay members interconnecting the upper plate member 122A and the lower plate member 122B. The stay members are parallel to each other and extend in a direction of extension which is orthogonal to the upper and lower plate members 122A,122B to form a stay structure, which forms a skeleton of a mechanical arm of the arm portion.

[110] The head portion comprises a retention device 142 for holding a welding gun. The head portion and the arm portion are interconnected by an immediate structure comprising a rigid member which is a first steel plate 132 and a rigid member 134 which is a second steel plate. The first steel plate 132 is movably mounted on the mechanical arm so that it is intermediate the upper and lower plate members 122A,122B.

[111] A coil spring having its coil axis parallel to the direction of extension of the stay members is disposed between the first steel plate 132 and the upper plate member 122A to provide spring urge to the first steel plate 132 such that when the first steel plate 132 is moved to approach the upper plate member 122A, for example, from a spring neutral position, the spring will urge the first steel plate 132 to return towards the spring neutral position; and when the first steel plate 132 is moved to depart from the upper plate member 122A, for example, from a spring neutral position, the spring will urge the first steel plate 132 to return towards the spring neutral position. The spring neutral position may be a position which is intermediate, for example, about midway between the upper and lower plate members 122A,122B.

[112] A surface tracker 152 is mounted on a lower end of the rigid member 134. The rigid member 134 comprises a steel plate which is outside of the mechanical arm and extends in a direction that is orthogonal to the first steel plate 132.

[113] The surface tracker 152 comprises a non-deformable wheel which is configured to track and follow surface profile of a support surface.

[114] As the first steel plate 132 is confined by the stay members to move in a direction orthogonal to the plate members 122A,122B between a first relative position and a second relative position, upward and downward movement of the surface tracker 152 will result in upward and downward movements of the first steel plate 132 along the stay members between the first relative position and the second relative position.

[115] In use, the working assembly is assembled with a carrier to form a welding apparatus, as shown in Figures 5A and 5B. When the welding apparatus is so assembled, the working assembly is carried by a carrier and is configured such that the weight of the working assembly is supported by the carrier with the surface tracker in compressive contact with a support surface. [116] After the welding apparatus has been assembled, the elevation level of the working head is set with reference to the carrier so that the working head is at a preset separation distance from a target location.

[117] When the apparatus moves along a support surface and there is a difference in elevation levels between the carrier and the surface being followed or tracked by the surface tracker 152, the difference in elevation levels will result in upward or downward movement of the head portion with respect to the arm portion which will result in a change in relative elevation level between the arm portion and the head portion and the extent of change is dependent in the difference, because the rigid member 134 is fixedly connected to the first steel plate 132, and the first steel plate 132 is movable relative to the mechanical arm between a first relative position and a second relative position under the constraint of the stay members.

[118] While the subject matter of the present disclosure is described with reference to examples and exemplary features, the examples and exemplary features should not be construed as essential or limiting. More specifically, while the exemplary features are described with reference to example embodiments, it should be appreciated that each exemplary feature is intended to have utility on its own right and can be utilized independent of the particular embodiment without loss of generality.

Claims

1. A working assembly of a welding apparatus, comprising an arm portion and a head portion, the head portion including a working head which is configured to facilitate performance of welding work on a target location; wherein the working head is mechanically supported by the arm portion and is movable relative to the arm portion between a first relative position and a second relative position, the first relative position being an un-extended position corresponding to a first elevation level relative to the arm portion and the second relative position being an extended position corresponding to a second elevation level relative to the arm portion; wherein the working assembly comprises a spacing tracking mechanism which is configured to follow or track surface profile of a surface and to move the head portion relative to the arm portion to adjust its relative elevation level with respect to the arm portion according to the surface profile so that the working head is at a preset separation distance from a target location.

2. The working assembly of claim 1 , wherein the working assembly is configured to perform welding on a plurality of target locations while moving in a first direction, and wherein the working assembly is configured to track and/or follow the surface profile of a surface leading to the plurality of locations and to move the head portion in a second direction relative to the arm portion according to the surface profile while moving in the first direction, the second direction being orthogonal or at an angle to the first direction.

3. The working assembly of claims 1 or 2, wherein the working assembly is configured to perform welding on a curved surface and the surface tracking mechanism is configured to track and follow a curved surface profile and to set the preset separation distance with reference to the curved surface profile.

4. The working assembly according to any preceding claims, wherein the working assembly is configured to perform welding on a plurality of target locations which are distributed along a curved path, and wherein the surface tracking mechanism is configured to track and follow a curved surface containing the curved path.

5. The working assembly according to any preceding claims, wherein the working assembly is configured to perform continuous automated welding while in motion, and wherein the working assembly is configured to be power-driven to move from one target location to another target location to perform continuous automated welding. The working assembly according to any preceding claims, wherein the working assembly comprises a spacing setting arrangement, wherein the spacing setting arrangement is configured such that the working head is at the preset separation distance from a target location when the working head is at a reference elevation level with respect to the arm portion, the reference elevation level being intermediate the first elevation level and the second elevation level. The working assembly according to any preceding claims, wherein the surface tracking mechanism comprises a surface-tracking component which is movable to track surface profile of a surface, and wherein the working head is configured to move relative to the arm portion following surface tracking movement of the surface-tracking component. The working assembly according to claim 7, wherein the surface-tracking component is movable relative to the arm portion under spring bias between a first elevation position and a second elevation position, and wherein the working head is at the first elevation level when the surface-tracking component is at the first elevation position, and at the second elevation level when the surface-tracking component is at the second elevation position. The working assembly according to any preceding claims, wherein the working head comprises a nozzle portion which is configured to feed a weld-facilitating medium towards a target location and to perform welding work on the target location with the weld-facilitating medium, and wherein the preset separation distance from the target location is a separation distance between the nozzle portion and the target location, the nozzle portion comprising a weld-wire feeding nozzle and/or an inert gas feeding nozzle. The working assembly according to any preceding claims, wherein the preset separation distance is between 8mm and 16 mm, including 8mm, 9mm, 10mm, 11 mm, 12mm, 13mm, 14mm, 15mm, 16mm, or a range or ranges selected from a combination of the aforesaid values, preferable between 10mm and 12mm. The working assembly according to any preceding claims, wherein the arm portion and a head portion are interconnected by a power-driven movement mechanism which is configured to move the head portion relative to the arm portion between an un-extended position and an extended position. The working assembly according to claim 11 , wherein the working assembly comprises a proximity sensor which is configured to provide control information to control operation of the power-driven movement mechanism whereby the working head is at the preset separation distance from the target location. The working assembly according to claim 12, wherein the proximity sensor comprises a magnetic surface which is configured such that when the magnetic sensor is attracted to move towards a surface containing the target location beyond a lower limit, the power- driven movement mechanism will operate to move the working head away from the target location. The working assembly according to claim, wherein the arm portion and the head portion are arranged in a telescopic manner such that the head portion is movable relative to the arm portion along a telescopic axis, and wherein parts, components and/or circuits of the power-driven movement mechanism are housed in a compartment defined by the arm portion and the head portion in cooperation. The working assembly according to claim, wherein the arm portion is elongate and comprises a first portion which is in abutment with the head portion and a second portion which is configured as a counterweight. The working assembly according to any of claims 1-10, wherein the surface tracking mechanism comprises a surface tracker which is configured to be in compressive contact with a support surface whereby the surface profile of the support surface is followed or tracked and whereby elevation of the working head relative to the arm portion is changed. The working assembly according to claim 16, wherein the surface tracker is configured to support weight of and provide mobility to the working assembly. The working assembly according to claim 16, wherein the arm portion comprises a mechanical arm, wherein the surface tracking mechanism comprises a rigid member which is in telescopic arrangement with the mechanical arm, and wherein the rigid member interconnects the rigid member and the working head. A welding apparatus comprising a working assembly according to any of the preceding claims and a carrier, wherein the carrier is configured to provide mechanical support and mobility to the working assembly so that the working assembly can perform welding while in motion. The welding apparatus of claim 19, wherein the carrier is a wheeled carriage which is configured to move and/or rotate the working assembly to facilitate performance of continuous welding on a plurality of target location.