WO2015006805A1

WO2015006805A1 - Programmable automated cutter/welder

Info

Publication number: WO2015006805A1
Application number: PCT/AU2014/000724
Authority: WO
Inventors: Michael Brown; Roy GREGORY
Original assignee: White Powder Pty Ltd
Priority date: 2013-07-17
Filing date: 2014-07-16
Publication date: 2015-01-22
Also published as: AU2014292801A1; AU2014292801B2

Abstract

A programmable automated cutter/welder apparatus (10) for cutting and/or welding a hollow cylinder (12), the apparatus 10 comprising: a head (assembly (14) for cutting/welding a wall (16) of the cylinder; an actuator assembly (18) mechanically coupled to the head assembly (14) for moving the head (assembly 14) relative to the wall of the cylinder (12); and a motorised carriage (28) for carrying the actuator assembly (18) and head assembly (14) around the circumference of the cylinder (12). The apparatus (10) also comprises a track assembly (32) adapted to be affixed to the cylinder (12) to provide a path on which the motorised carriage (28) can travel around the circumference of the cylinder (12); and, a programmable data processing device (40) operatively connected to the motorised carriage (28) and the actuator assembly (18) for controlling the motion of the motorised carriage (28) and the head assembly. In use, the speed of the motorised carriage (28) and/or the position of the head assembly (14) is controlled to produce a desired cut and/or weld in the wall of the cylinder (12). The track assembly (32) comprises a guide track (34), a clamp arrangement (70), and a pair of elongate adjustable actuators (80).

Description

"PROGRAMMABLE AUTOMATED CUTTER/WELDER"

Field of the Invention

The present invention relates to a programmable automated cutter/welder apparatus and method and relates particularly, though not exclusively, to such an apparatus and method for cutting and welding raked piles.

Background to the Invention

An example of current methods of cutting and welding of piles will be given with reference to a typical wharf design. A wharf typically comprises a series of large steel hollow cylinders (piles) driven into the ocean floor to be utilized as supports for further structures to be built upon the piles. These piles normally consist of a plurality of both vertical and raked piles. The pile angle varies based on the design. Once the piles have been driven to refusal (set in place), the piles are required to be horizontally cut to a finished height specified by the site surveyor.

The piles are typically cut by hand using an oxy/acetylene cutting tool in a minimum two stage process: Firstly, a rough cut is performed about 50mm above the final height, to remove excess pipe. Secondly, a horizontal cut is made at the desired finish height specified by the site surveyor. Thirdly, a final angle cut is performed as preparation for welding. The final cut is made at a predetermined design cut angle (~ 30° to 45° to the horizontal). Manual cutting of the piles results in an uneven surface, which therefore requires hand grinding to provide a clean and precise weld surface finish. This process is repeated for all of the raked and vertical piles that will be supporting one section of headstock.

A structure is then placed on top of the cut piles (e.g. headstock, typically made of reinforced concrete). When the piles have been cut by hand, it is common (probably usual) for a visual inspection to indicate a need for further re-work of the weld preparation. Hence the headstock would then be removed to allow further grinding of the weld preparation before replacing the headstock. The headstock is provided with a steel plate on its under-surface which is then welded to the tops of the piles. With headstock in place atop the piles, the low head clearance forces the boilermaker-welder to hold and work in a compromising body position throughout the duration of the welding process. Manual welding is flawed with stop/starts throughout the circumference of the pile, as the boilermaker-welder changes position. The integrity of the weld is fully dependent on the boilermaker-welder ensuring the welding tip is held at the correct distance and angle from the weld whilst also maintaining the correct and consistent speed of the welding handpiece. Throughout the entire welding process the tradesman is subjected to all the usual safety issues consistent with the welding processes. On many occasions more than one tradesman will carry out the welding of the pile at the same time which further exacerbates the safety issues. Automatic cutting and welding of steel hollow cylinders (such as vertical piles and tanks) is not uncommon. However, cutting and welding of raked piles presents problems too compiicated for current off-the-shelf machines: i. Current track systems for automated cutting and welding machines are unable to provide a horizontal platform for the cutting or welding machine when they are used on raked piles. ii. When a raked pile is cut off at the horizontal, the sectional cut is an elliptical shape so a cutting/welding tip needs to follow this shape. iii. Most advanced of the current technology uses a pantograph to maintain the correct distance from the cutting/welding tip to the material being cut/welded. The changing angle of the raked pile

(which goes from an acute to an obtuse angle to the horizontal) makes a pantograph unsuitable. iv. The starting height for the weld preparation cut changes around the horizontal elliptical section. v. The depth of the cut and hence the depth of the weld changes around the horizontal elliptical section.

The present invention was developed with a view to providing a programmable automated cutting and/or welding apparatus and method which reduces the time to do the task, reduces the safety issues associated with manual cutting and/or welding of raked piles and results in a better quality cut and weld. Whilst the following description will be given primarily with reference to cutting and welding of raked piles, it will be appreciated that the invention may have wider application where similar problems have to be overcome.

References to prior art documents in this specification are provided for illustrative purposes only and are not to be taken as an admission that such prior art is part of the common general knowledge in Australia or elsewhere.

Summary of the Invention According to one aspect of the present invention there is provided a programmable automated cutter/welder apparatus for cutting and/or welding a hollow cylinder, the apparatus comprising: a head assembly for cutting and/or welding a wall of the cylinder; an actuator assembly mechanically coupled to the head assembly for moving the head assembly relative to the wall of the cylinder; a motorised carriage for carrying the actuator assembly and head assembly around the circumference of the cylinder so as to cut and/or weld the wall of the cylinder around a section through the wall that can be of elliptical shape; a support structure adapted to be affixed to the cylinder to provide a path on which the motorised carriage can travel around the circumference of the cylinder; and, a programmable data processing device operatively connected to the motorised carriage and the actuator assembly for controlling the motion of the motorised carriage and the head assembly wherein, in use, the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a desired cut and/or weld in the wall of the cylinder that follows the shape of the section through the wall. Preferably in a cutting mode the programmable data processing device is programmed to vary the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder. Preferably in the cutting mode the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a cut that is substantially horizontal on an inner edge of the wall of the cylinder. Preferably in the cutting mode the programmable data processing device also automatically maintains a predetermined distance between a cutting tip of the head assembly and the wall of the cylinder.

Preferably the actuator assembly comprises a first linear actuator for moving the head assembly horizontally in the direction of an X-axis, and a second linear actuator for moving the head assembly vertically in the direction of a Z- axis. Typically each linear actuator is driven by respective first and second stepper motors, the linear actuators converting the rotation of the stepper motors into a linear movement. Preferably the motorised carriage is driven by a third stepper motor along a P-Axis at a programmable speed.

Advantageously the apparatus further comprises a distance sensor, also carried on the motorised carriage and operatively connected to the programmable data processing device, for sensing the distance between a cutting tip of the head assembly and the wall of the cylinder wherein, in use, the distance sensor sends distance measurements to the programmable data processing device which in turn calculates and sends a compensation signal to the actuator assembly.

Preferably the head assembly is an interchangeable head which can be easily switched between a cutting tip in a cutting mode, and a welding gun in a welding mode. According to another aspect of the present invention there is provided a method of cutting and/or welding a hollow cylinder using a programmable automated cutter/welder apparatus, the method comprising the steps of: moving a cutting and/or welding head assembly relative to a wall of the cylinder using an actuator assembly mechanically coupled to the head assembly; carrying the actuator assembly and head assembly around the circumference of the cylinder using a motorised carriage so as to cut and/or weld a wall of the cylinder around a section through the wall that can be of elliptical shape; providing a path on which the motorised carriage can travel around the circumference of the cylinder using a support structure adapted to be affixed to the cylinder; and, controlling the motion of the motorised carriage and the actuator assembly using a programmable data processing device operatively connected to the motorised carriage and the actuator assembly wherein, in use, the speed of the motorised carriage and/or the position of the actuator assembly is controlled to produce a desired cut and/or weld that follows the shape of the section through the wall.

Preferably in a cutting mode, the programmable data processing device is programmed to vary the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder.

Typically the step of moving the head assembly involves moving the head assembly in the direction of an X-axis and/or a Z-axis wherein the distance and/or angle of the head assembly relative to the wall of the cylinder can be varied.

Preferably the step of controlling the motion of the motorised carriage involves moving the motorised carriage along a P-Axis at a programmable speed. Preferably in a cutting mode the step of controlling the motion of the motorised carriage and the actuator assembly involves to varying the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder. Preferably in the cutting mode the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a cut that is substantially horizontal on an inner edge of the wall of the cylinder.

Advantageously an indexed counting system is utilised that decouples the cutting profile from the diameter and/or rake angle of the cylinder, making the system applicable for any diameter cylinder of a given rake angle or straight vertical orientation. Preferably an angular distance for the motorised carriage (P-Axis) is defined as a function of counts in a flat plane (P), and movement of the actuator assembly is controlled by calculating the rise and fall of Z-Axis distance counts in a synchronous fashion as a function of the counts to give a precise cut over the defined distance.

Preferably the head assembly is an interchangeable head which can be easily switched between a cutting tip in a cutting mode, and a welding gun in a welding mode.

According to a further aspect of the present invention there is provided a track assembly for a programmable automated cutter/welder apparatus for cutting and/or welding a hollow cylinder, the track assembly comprising: a guide track to provide a path on which a motorised carriage of the programmable automated cutter/welder apparatus can travel around the circumference of the cylinder so as to cut and/or weld a wall of the cylinder around a section through the wall that can be of elliptical shape; a clamp arrangement adapted to clamp to an outer circumference of the cylinder; and a pair of elongated adjustable actuators for supporting the guide track, each adjustable actuator having one end mounted on the clamp arrangement and the other end connected to the guide track wherein, in use, the length of the adjustable actuators can be varied to adjust the angle at which the guide track is supported relative to the cylinder.

Preferably the clamp arrangement is in the form of a clamp ring that clamps around the cylinder and acts as an anchor point for the rest of the track assembly. Typically the clamp ring is formed in two halves which are joined together about the cylinder to form the complete clamp ring.

Typically the guide track is of circular shape and is formed in two halves. Preferably the guide track is an I-beam rolled into the desired shape. Preferably the guide track is supported on each adjustable actuator via a base plate. Advantageously the base plates perform a dual function of connecting the two halves of the guide track together.

Preferably the angle of the adjustable actuators can also be varied to enable the guide track to be positioned independently and without restriction on the vertical and horizontal axes relative to a position of the hollow cylinder. Once the guide track is in position, a pair of adjustable struts is typically attached to the clamp arrangement and the guide track, perpendicular to the adjustable actuators, providing additional guide track support.

Throughout the specification, unless the context requires otherwise, the word "comprise" or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers. Likewise the word "preferably" or variations such as "preferred", will be understood to imply that a stated integer or group of integers is desirable but not essential to the working of the invention. Brief Description of the Drawings

The nature of the invention will be better understood from the following detailed description of several specific embodiments of the programmable automated cutter/welder apparatus and method, given by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side elevation of a first embodiment of a programmable automated cutter/welder apparatus according to the present invention;

Figure 2 shows the motorised carriage and actuator assembly of the apparatus of Figure 1;

Figure 3 is a schematic circuit diagram for the electrical components of the apparatus of Figure 1 ;

Figure 4 is a cross-section view of a section of a raked pile showing how the length of the cut and the starting height of the outer edge of the cut varies around the circumference of the pile;

Figure 5 is a side elevation of a raked pile illustrating the resultant deviation of the inner cut line from true horizontal if the cutting tip follows a horizontal profile;

Figure 6 is a side elevation of the programmable automated cutter/welder apparatus of Figure 1 shown with a track assembly on a raked pile;

Figure 7 is a top perspective view of one embodiment of the track assembly for the programmable automated cutter/welder apparatus of Figure 1 ;

Figure 8 is a top perspective view of one embodiment of a clamp arrangement which is part of the track assembly of Figure 7;

Figure 9 is a top perspective view of one embodiment of the guide track with adjustable actuators of the track assembly of Figure 7; and, Figure 0 is a cross section view of an embodiment of a support strut employed in the track assembly of the programmable automated cutter/welder apparatus of the invention.

Detailed Description of Preferred Embodiments

A preferred embodiment of the programmable automated cutter/welder (PACW) apparatus 10 in accordance with the invention, as illustrated in Figures 1 to 3, is designed for cutting and/or welding a hollow cylinder 12. The apparatus 10 comprises a head assembly 14 for cutting/welding a wall 16 of the hollow cylinder 12. Typically the head assembly is an interchangeable head 14. The interchangeable head 14 can be easily switched between a cutting tip in a cutting mode, and a welding gun in a welding mode. An actuator assembly 18 is mechanically coupled to the interchangeable head 14 and is designed to move the interchangeable head relative to the wall of the cylinder 12. In the illustrated embodiment the hollow cylinder is a steel pile 12.

In the illustrated embodiment the actuator assembly 18 comprises a first linear actuator 20 for moving the interchangeable head 14 horizontally in the direction of the X-axis, and a second linear actuator 22 for moving the interchangeable head 14 vertically in the direction of the Z-axis, as shown most clearly in Figure 2. Each linear actuator 20, 22 is driven by respective first and second stepper motors 24, 26. The linear actuators convert the rotation of the stepper motors into a linear movement.

A motorised carriage 28 is provided for carrying the actuator assembly 18 with the interchangeable head 14 around the circumference of the cylinder 12. The motorised carriage 28 is driven by a third stepper motor 30 along the P-axis, as shown in Figure 2. The PACW preferably provides simultaneous, automated control of the X-axis (horizontal linear actuator), Y-axis (vertical linear actuator) and the P-axis (PACW moving around the track) to enable the required cutting or weiding head to complete a formulated path as it traverses the circumference of the pile.

A support structure 32 is also provided, and is adapted to be affixed to the cylinder 12 to provide a horizontal path on which the motorised carriage 28 can travel around the circumference of the cylinder 12. The term "circumference" as used throughout the specification refers to the full distance around the cylinder, which may or may not be a circle. In the illustrated embodiment, where the cylinder 12 is a raked pile, the elliptical circumference is at an angle of 20° to the horizontal (for a 70° raked pile); however what the support structure 32 provides, and the motorised carriage 28 follows, is a horizontal circular path about the circumference. Therefore the horizontal distance to the pile is constantly changing around the circumference of the support structure 32.

In the illustrated embodiment the support structure is in the form of a track assembly 32 and comprises a guide track 34 of circular shape which is support via an adjustable support frame 36 and a plurality of adjustable support arms 38 on the outer circumference of the wall 16 of the pile 12 below the desired location of the cut/weld. The support frame 36 and support arms 38 can be adjusted until the guide track 34 is perfectly horizontal as measured using precision levelling equipment. Although the apparatus is described in connection with a raked pile, it will be apparent that it may equally be used in connection with a vertical pile. Furthermore, it is not necessary for the motorised carriage 28 and/or the actuator assembly 18 to follow a horizontal path (as in the described embodiment); the apparatus may also be configured and programmed to follow a formulated path at any desired angle.

The design and assembly method of an embodiment of the track assembly 32 will be described in more detail below with reference to Figures 6 to 10.

The programmable automated cutter/welder (PACW) apparatus 10 further comprises a programmable data processing device 40, operatively connected to the motorised carriage 28 and the actuator assembly 18, for controlling the motion of the motorised carriage 28 and the actuator assembly 18. In use, the speed of the motorised carriage 28 and/or the position of the actuator assembly 18 is controlled by the data processing device 40 to produce a desired profiled cut and/or weld around the wall 16 of the cylinder 12 according to a formulated path, in the illustrated embodiment the programmable data processing device is a Programmable Logic Controller (PLC) 40, as shown in Figure 3. The PLC 40 incorporates a microprocessor for processing various data and executing various programmes.

Preferably the tip 42 of the cutting head and/or the welding gun is maintained at predetermined distance from the wall 16 of the hollow cylinder 12 (pile) and at a pre-set angle to the horizontal by the PACW 10. The height profile to be followed by the cutting tip will change when any of the following input parameters change (the welding tip will always follow a horizontal profile):

* pile diameter,

· wall thickness of the pile,

• pile rake (the angle of the longitudinal axis of the pile from the vertical).

The changing height profile is explained with reference to Figures 4 and 5.

In the illustrative example of Figure 4, showing a cross-section of a raked pile 12, it can be seen that the angle of the cut through the wall 16 of the pile is to be maintained at a constant pre-set angle of 35° to the horizontal, around the entire circumference of the cylindrica! pile 12. In the illustrated example, the pile 12 itself is raked at an angle of 70° to the horizontal, and has a constant wall thickness of t = 25mm around the circumference of the pile. However the length of the cut through the wall will vary about the circumference of the pile, from a maximum length of Li on one side of the pile, to a minimum length L₂ on the opposite side of the pile.

In order to achieve a horizontal finish to the inner edge of the cut pile, it is necessary for the height 'h' of the cutting tip 42 to be slightly varied. On the other hand, during welding the tip 44 of the welding gun maintains the same height as it travels around the circumference of the pile. Furthermore, in order to maintain the quality of the cut/weld around the full circumference, it is necessary: i. to keep the distance 'd' between the cutting tip 42 and the point of entry of the cut in the wall 16 constant (in this example, d = 5mm). ii. to keep the distance between the welding tip and plane of welding constant (in welding mode the welding tip needs to gradually move away from the pile as the weld is built up - there is about 30 beads of weld applied to each pile.)

The guide track 34 for the prototype PACW 10 was set-up at true horizontal around the circumference of a pile 12 with an outside diameter of 016mm and a wall thickness of 25mm. It was found that the initial finished cut heights were ali lower on the far side of the pile with a fixed height cutting tip 42. A computer model was created to simulate the cutting path if the cutting tip followed a horizontal profile in relation to the geometry of the cut pile 12. With a pile 12 raked at 70°, and a preparation cutting angle of 35° the finished cut height on the inner circumference of the cut dropped by 0.15mm from the high point on the circumference to the low point, as shown in Figure 5.

Using the computer simulation, data was collected and a formula was developed to compensate for the drop in finished inner cut height. The formula was tested, and found to be accurate, for a range in cutting angle from 0° to 45°. Larger angles would require a modified formula. The height of the cutting/welding tip 42/44 is controlled by the PLC 40 that has been programmed with the formula to calculate the required cutting/welding profile as a function of four variables (pile diameter, wall thickness, rake angle and torch angle). The variables may be entered into a user display on the machine via a QAV (question, answer and validation) user interface.

The PACW 10 utilises an indexed counting system that decouples the cutting profile from pipe diameter, making the system applicable for any diameter pipe of a given rake angle or straight vertical orientation. The raked angle profile formulas, which are derived from the empirically collected data, have been mathematically arranged such that they relate back to a 360° circumference in a level X/Y plane. This allows an angular distance to be defined as a function of counts in a flat plane (P) for the track drive motor (P- Axis). In turn this master counter is used by the PLC code to calculate the rise and fall of the Z-Axis distance counts to drive both motors in a synchronous fashion as a function of steps to give a precise cut over the defined distance, effectively projecting an elliptical cutting path from the level P track plane to provide a finished level cut.

It took some time to visualise and figure out that the formula has nothing to do with the ellipse distance. Rather it has everything to do with the total track distance. When this is projected from the flat level plane up to the cutting plane, then the finished cut forms an ellipse. By defining the total track distance as a function of counts it is possible to get accurate control. It is not possible to use a measured track distance as there are too many variables (thermal expansion of track, wheel slip, etc). Defining the track distance as a function of counts/pulses enables the system to be decoupled from track/pipe variations.

Preferably a mechanism for controlling the distance of the cutting/welding tip 42/44 from the pile is also provided. Preferably an automatic distance control mechanism is provided, in which a distance sensor 46 is used for sensing the distance between the cutting/welding tip 42/44 of the interchangeable head and the wall 16 of the cylinder 12. Alternatively the distance can be controlled manually via a remote control device, e.g. using a pendant control unit 52 (hand held controller linked to the PACW via short cable) and then input into the PLC. Preferably the distance sensor is a laser sensor 46, and is also carried on the motorised carriage 28 and operatively connected to the PLC 40. In use, the laser sensor 46 sends distance measurements to the PLC 40, which in turn calculates and sends a compensation signal to the actuator assembly 8. The laser sensor 46 is also used to measure and record the shape profile around the full circumference of the pile 12 by sending the motorised carriage once around the guide track in a recording mode (see further below). The PLC 40 uses this shape profile in all subsequent calculations of the formulated path for the cutting/welding tip. in welding mode another formula needs to be applied, because the depth of the weld changes around the circumference of the pile. Without the welding formula, the pendant control unit (PCU) 52 is used to set the right distance and then enter that distance into the PLC 40 - after that, the laser sensor 46 wiil ensure that distance is maintained.

The PACW 10 is powered by the Power Supply Unit (PSU) (not illustrated). The PSU has a single phase 240 Volts at 50 Hz input that supplies two 36 Volts maximum of 8.8 Amps per supply to the PACW 10 through a six (6) meter long umbilical cable. The output voltage and amperage is required to power the three stepper motors 24, 26 and 30, the PLC 40, the laser sensor 46 and a printed circuit board (PCB) 48. The PCB 48 incorporates a signal converter which translates the signal between the PLC 40 and the stepper motor drivers, and also isolates the PLC from electrical problems that otherwise would destroy the PLC 40. PCB 48 also includes a DC/DC converter for changing the input voltage of 36 Volts to 12 Volts for the PLC 40 and the laser sensor 46. A PACW casing 50 houses the PLC 40, the PCB 48, the stepper motor drivers 54 (motion control units), an LCD screen and a numerical keypad for data entry and menu selection. The pendant control unit (PCU) 52 (or a wired remote) is connected and hooked to the casing 50 that allows the operator to control the PACW 10 in manual mode. A terminal 58, (see Figure 3) attached to the casing 50, includes the LCD screen and keypad for data entry.

The PLC 40 is a microprocessor which can execute uploaded programs written in compiled machine code. The PLC 40 receives information independently from the laser sensor 46, the PCU 52 and the keypad. The information is processed in the PLC and sent as execution commands, called signals, to the signal converter on the PCB 48 (see Figure 3). The converted signals are relayed to the appropriate stepper motor driver which sends the required number of pulses to the corresponding stepper motor. The rotor of each stepper motor turns 1.8 degrees per pulse sent by the corresponding stepper motor driver. The first and second linear actuators 20, 22 convert the rotation of the respective stepper motors 24, 26 into a linear movement. The current configuration moves the linear actuator table 2mm per one full revolution of the stepper motor.

The P-axis stepper motor 30 moves the PACW 10 along the guide track 34 at a predetermined speed given in pulses and frequency. A drive wheel 56, with two O-rings around it made from Viton (Fluorocarbon Type A), provides higher friction between the drive wheel 56 and the track 34. Viton, among other benefits, is high wear-resistant and temperature-tolerant. The drive wheel 56 is secured directly to the rotor axis of stepper motor 30.

The second linear actuator 22 moves the X-axis linear actuator 20 up and down in the direction of the Z-axis. This movement is required in cutting mode when cutting the pile 12. In cutting mode the PLC 40 defines a particular up and down movement, based on the formula, to compensate for the geometric variance of the cutting line, whilst keeping the motorised carriage 28 travelling at a defined speed. While cutting the PLC 40 controls the P-axis and the Z-axis accordingly. In recording mode the P-axis is measured and recorded by carrying out a track scan procedure with the PACW. Once the PACW is set-up on the guide track, it is placed at the cut/weld start/finish point of the pile and the track scan is initiated via the user interface. As it travels around the P-axis (the track) the program automatically counts and records the number of pulses required to complete one full circumference. This number is stored and used as the main index counter maximum value and represents the pipe circumference as counts. The total pulse count is fed into the master formula along with, torch angle, rake angle, pipe wall thickness, and pipe diameter. The rise and fall of the Y-axis around the circumference of the pipe is then calculated. Then the cutting tip 42 is installed and a reference distance set to the pipe wall. The cutting tip is then removed and the laser mounted on the carriage so a profile scan can be done (note the laser dot and cutting tip must be aligned to the same spot). The laser is activated and the calculated cut path is run for the full circumference of the pipe. For every index pulse a distance measurement from the laser is taken and stored in memory. When the laser profile scan is complete a memory array is built in the computer (shown below). Whereby N is the end of the circumference and hence cut distance in counts.

P Drive Index Z Drive Index X Drive Index Counts

Counts Pulse (Height) (Cutting Tip Distance)

(Circumference)

1 Z Cut Height (1 ) X Cutting Tip Distance (1 )

N Z Cut Height (N) X Cutting Tip Distance (N)

The laser uses optical triangulation to determine the distance from a fixed reference point to the pipe surface. A red laser beam of 670mm wavelength is emitted from the laser sensor 46 to the surface to be measured. The reflected dot is picked up by a CCD camera in the sensor and a distance calculated. The CCD uses optical filters to remove any spurious light sources and only pass the laser wavelength, but if the CCD camera window or red dot light source is "swamped" by external light entering the CCD window or reflected from the surface then the accuracy of the measurement will drop. Preferably screens are used to shield the laser from other light sources, particularly in proximity to welding equipment (this is why we can't run the torch tip control whilst cutting, this is a common issue with laser distance measurement devices). For example, the PACW has been modified to include an aluminium shroud to protect the laser from sunlight or water reflection.

Once the X, Y and P-axes are programmed into the PACW, it is then ready to carry out automated cutting. The cutting attachment is fitted to the X-axis linear actuator by means of a dovetail joint, and then the cutting sequence is initiated via the user interface QAV instruction input.

The PCU 52 can be used to override programmed instructions to the X, Y and P-axes during the cutting or welding operation. For example, if during cutting of the pile the cutting tip blocks and requires changing, operation can be paused on the user interface and the PCU 52 used to position either of the actuators to a position which makes it easy to change the cutting tip. Then the actuators can be repositioned, the cutting tip reignited, and the Resume button on the user interface pressed to continue cutting. in welding mode the PACW is currently controlled manually through the PCU 52 by the operator. The PLC currently has no control over the Z-axis and X- axis in welding mode; it only controls the defined speed along the P-axis for welding to ensure consistent weld quality. The current intention is to develop a semi-automated process that will use the X-axis shape (i.e. the elliptical shape) that is input to the PLC 40 from the laser scan. A manual or preprogrammed step adjustment will be used to enlarge the ellipse for each successive run. However, in future it is envisaged that the PLC 40 will be programmed to also perform fully automated welding.

The X-axis linear actuator 20 moves the interchangeable head 14, either closer or further away from the wall 6 of the pile 2, in order to maintain a constant distance between the cutting tip 42 and the pile cut surface. A variance in cutting distance would result in a poor quality cut. In cutting mode the laser sensor 46 sends distance measurements, in the form of low voltage signals, to the PLC 40. The PLC 40 processes the signal and in turn sends a compensation signal to the stepper motor. The X-axis linear actuator 20 is therefore in constant motion to maintain correct distance between the cutting tip 42 and the pile cut surface, which is an elliptical shape for a raked pile cut at the horizontal. In welding mode the laser sensor 46 is currently disabled for further testing and the distance is controlled by the operator. The preferred design and method of assembly of an embodiment of the PACW track assembly 32 will now be described in more detail with reference to Figures 6 to 10. Advantageously the PACW track assembly 32 is fabricated from aluminium, which allows the guide track to be lightweight, but strong in design and very easily fitted by one person. The track assembly 32 typically comprises four major components:

• A clamp arrangement in the form of clamp ring 70

• Two adjustable actuators 80

• The guide track 34

· Two to six support struts 90

The clamp ring 70 is an aluminium strap that clamps around the pile and acts as an anchor point for the rest of the track assembly 32. The clamp ring 70 is fabricated for a specific pile diameter and is only suitable for use on piles of that specific diameter. The clamp ring of Figures 7 and 8 is designed for a pile with a typical outside diameter of 1700 to 1800mm. In the description below it is assumed that the pile is driven into the ground raking (i.e. leaning) towards the North.

The clamp ring 70 comes in two halves 70a and 70b respectively. One of the halves (half 70a) has a centreline marked on it. Half 70a of the clamp ring is placed around the pile so that the centreline marked on the clamp lines up with the back centreline of the raked pile 12 (i.e. the southern point of the pile). The second half 70b of the clamp ring is then placed around the pile and attached to half 70a. There are quick release magnets permanently attached to clamp ring half 70a, which are switched on once half 70a is in the right position relative to the back centreline of the pile but before connecting the second half 70b to form a clamp ring around the circumference of the pile 12. Before the quick release magnets permanently attached to clamp ring half 70a are switched on, clamp ring half 70a is supported on quick release magnets temporarily attached to the pile. A plurality of mounting brackets are permanently attached to the clamp ring 70 for mounting the adjustable support arms 38 on the pile 12. There are two types of adjustable support arms 38 in the track assembly 32, namely, adjustable actuators 80 and support struts 90. Two mounting brackets 72a and 72b are provided for attaching the two adjustable actuators 80. These brackets are attached on the c!amp at a point where they would be vertically aligned with an east-west line through the centre of the pile at the cutting plane (not the plane of the track) for a pile raked at 75°. The reason for this positioning is explained in more detail below, but it allows the track assembly to function for a range of pile rake angles from 90° (i.e. vertical) to 60°. A plurality of mounting brackets 74 are provided for attaching the support struts 90.

The two adjustable actuators 80 slide into the mounting brackets 72 using a T-slot joint. The adjustable actuators 80 are mounted on opposite sides of the pile 12. At the top end of each adjustable actuator 80 is a base plate 82 to connect to the guide track 34 (see Figures 6, 7 and 9). This is the main support for the guide track 34 and takes most of the weight of the PACW machine when mounted on the track. The height of the base plate can be adjusted in a range of 150 mm by turning a winder 84 of the adjustable actuator, assuming the adjustable actuator 80 is mounted in a vertical orientation, as shown in Figure 6. The adjustable actuators 80 are used to level the guide track 34 on the east-west axis (typically by adjusting the height of one adjustable actuator only).

The centre of the base plate 82 needs to approximately align with the east- west line through the centre of the pile at the cutting plane (not the plane of the track). This is referred to as the centreline of the pile 12, marked "C" in Figure 6. This ensures that the horizontal distance from the guide track to the cutting point at the north point of the pile is approximately equal to the horizontal distance from the guide track to the cutting point at the south point of the pile. If this distance is too unequal, then the range of the horizontal actuator 20 on the PACW might be unable to maintain the constant distance between the cutting distance and the piie (which is critical for the cutting operation).

For any one pile rake angle, the track assembly 70 can be configured to achieve this result (where the centre of the base plate 82 aligns with the centreline C at the cutting plane). However, when an angle is specified for the raking of piles there will be tolerance limits for variations from the specified angle. Therefore it is important to have a track assembly that can accommodate a range of angles for the pile rake. This is also important to make the guide track 34 suitable for use in a range of specified rake angles. To enable the track assembly 70 to be adapted to a wide range of rake angles (90° or vertical to 60° rake angle), the adjustable actuators 80 are able to pivot up to 15° at both the base and at the top around the east-west axis. As the rake angle of the pile decreases (i.e. the top of the pile moves further north from the vertical) the east-west centreline of the cutting plane moves to the north. Therefore, the top of the adjustable actuator needs to move to the north which it is able to do by rotating around the base pivot. The track base plate 82 then rotates in the opposite direction around the top pivot so that the base plate remains horizontal. Because the track assembly is designed so that the adjustable actuator 80 is vertical when the pile is raked 75°, the ability to pivot the adjustable actuator by 5° in either direction allows the track assembly to accommodate a pile rake of 90° to 60°. However, in the current configuration, the overall diameter of the track will become a limitation before the pile reaches a 60° rake - as the pile rake decreases the horizontal section of the pile becomes a longer ellipse and eventually a larger diameter track is required.

The guide track 34 is an aluminium I-beam, as can be seen most clearly in Figure 9, used to support and guide the PACW machine as it traverses around the pile. The guide track 34 is rolled to suit a specific diameter pile but will accommodate small differences in pile diameter. The guide track 34 is attached to the base plate 82 on top of the adjustable actuator 80 by a dovetail joint 86 between the top of the base plate and the underside of the guide track. The dovetail joint 86 allows the track to be easily assembled and also provides torsional strength to the guide track.

In fabrication, the male component 88 of the dovetail joint is bolted to the bottom web of the guide track i-beam. The guide track 34 is in two halves which are clamped together when assembled, and the male component 88 of the dovetail joint is in one piece when bolted to the track. The centreline of the dovetail joint is iined-up with the join in the track before being bolted on. The male component 88 of the dovetail joint is then cut in line with the join in the track so that when the track is undamped each half of the track has its own male component of the dovetail joint bolted to the underside of the guide track 34 (there are two for each half circle of track - one at each join). This helps ensure alignment of the track halves when they are put together using the dovetail joint.

There is a further modification to the guide track to ensure perfect alignment of the web of the guide track I-beam 34. The base plate 82 connected to a female component of the dovetail joint has been modified to allow for small adjustments in an east-west direction on one half of the track. The base plate 82 is fitted to the top of the adjustable actuator 80 with another dovetail joint that is aligned with the east-west centreline axis of the pile on the cutting plane. The dovetail joint allows the base plate 82 to be shifted either east or west (by up to 20 mm each way from the centre point in the current track assembly unit). This allows the base plate 82 to be shifted east or west to accommodate:

(i) a guide track 34 that has a smaller or larger diameter, in case the rolling does not give a track of the exact target diameter; and,

(ii) contraction and expansion of the track with changing temperatures.

The track assembly 32 preferably further comprises a pair of elongated support struts 90, which are machined from billet aluminium and aluminium pipe, as shown in Figure 10. Figure 10 shows the two halves of a support strut 90 separated. Each strut 90 has a series of holes 92 along its length to provide macro length adjustments, (30mm per hole in a similar manner to tent poles) and a micro-screw 94 to provide micro length adjustment of 130 mm between holes 92. Each strut is connected at one end to one of the mounting brackets 74 respectively, on clamp ring 70, and is connected at the other end to a similar bracket bolted to the underside of the guide track 34. There are two to six struts 90 per guide track depending on the size of the pile.

The support struts 90 are used to level the track on the north-south axis and provide additional support to the guide track (i.e. additional to the main support provided by the base plates 82 on top of the respective adjustable actuators 80).

A typical assembly process for the track assembly 34 is as follows: a. Mark the back centreline on the southern most point of the raked pile (referred to below as the centreline mark). This is not required when cutting vertical piles.

b. Transfer the finish cut height mark using a calibrated water line to the centreline mark. Surveyors will have previously marked the desired finish cut height on the pile at a random point around the circumference. c. Measure 700mm along the back of the pile going down from the finish cut height at the centreline mark (it does not need to be exactly 700mm). This will be referred to as the clamp height mark.

d. Position quick release magnet 100mm below the clamp height mark on the pile centreline.

e. Position the first half 70a of the clamp ring on top of the quick release magnet and align the permanent centreline mark on the clamp ring with the centreline mark on the pile. Align the first half 70a of the clamp ring perpendicular to the length of the pile and switch on the quick-release magnets on the first half 70a to enable it to stay in position unassisted. f. Hook the second half 70b of the clamp ring to the fitted first half 70a, wrap it around the pile to align the two half clamp ring over-centre locking mechanisms and lock them together. Together, the two halves form a complete clamp ring 70 around the pile 12, thus providing the foundation for the guide track 34 to be built upon.

g. Attach the two adjustable actuators 80 to both sides of the clamp ring 70 by aligning the dovetail connections and lowering them into position and securing them to the clamp ring by tightening the kip spanner on each. h. Attach both halves of the guide track 34 to the respective adjustable actuators 80 by aligning the dovetail joins on either end of the guide track halves with the dovetail joins on the actuators and sliding them into position.

i. Secure the track halves to the actuators by tightening the adjustable dovetail connections of the actuators. This will secure and centralise the two track halves combining them to make one complete guide track 34 for the PACW machine to run along.

j. Release the adjustable actuator top pivot retainer bolts to allow the guide track to pivot at the central axis,

k. Swivel both actuators backward or forward to find the approximate central position of the guide track to the cut position on the pile (within

20mm).

I. Secure the actuator lower pivot retainer bolts to disable any actuator swivel movement

m. Place a level on the track in line with the two adjustable actuators and adjust the actuator/s up or down until the levels shows the track is horizontal.

n. Place the level across the guide track, 90° from the last position, and tilt the track until the level shows horizontal. Secure the front and back support struts and double check levels in both directions.

The track is now ready to fit the PACW machine.

Overall the track assembly 32 has been designed to:

• Facilitate safe, easy and quick assembly by using:

o aluminium materials for lightweight construction

o dovetail and T-slot joints o fasteners which do not require spanners for tightening

o very simple system to levei the guide track;

• Provide a horizontal track irrespective of the rake angle of the pile; and

• Provide a guide track that will enable the PACW 10 to operate successfully across a wide range of angles for the pile rake.

The PACW 10 can be used to replace the current manual two or three step process for preparing a raked pile for welding to headstock. After the pile is driven into the ground/sea bed, a surveyor will mark the required finishing height on the pile and the PACW 10 will perform a single horizontal cut of the pile at the required finish height, with the 30° to 45° angle weld preparation cut incorporated. The linear actuators that control the movement of the cutting tip is controlled by PLC 40, which is programmed to ensure a horizontal finishing height. This is repeated for all of the piles that will be supporting one section of headstock. The headstock is then lowered onto the pile. The piles are then welded to the headstock using the PACW 10. The position and speed of the welding tip is again controlled by the PLC and linear actuators OR the speed is controlled by the PLC while the z-axis position is manually controlled by the operator via the PCU 52.

Now that a preferred embodiment of the programmable automated cutter/welder apparatus and method has been described in detail, it will be apparent that it provides a number of advantages over the prior art, including the following: (i) The pile is cut only once instead of two or three times - the current method is (a) once to cut off the excess pile, (b) once to set the required height and (c) once to prepare it for welding. Sometimes steps (a) and (b) are combined,

(ii) The cutting quality is better, leaving a precise, clean weld surface which requires minimal clean-up grinding. (iii) The welding quality is better - the weld is of flawless quality with one start point and one stopping point throughout each traverse of the circumference of the pile, and a constant welding speed and a constant distance between the welding tip and the point of laying the weld. Automated welds checked by radiography testing show perfect results

(iv) The cutting is quicker. The big saving is not having to do as many cuts and not having to grind the final weld preparation. Once cutting commences, the process is significantly more efficient but there will be some set-up time for the PACW. A rough (and conservative) estimate is that it will take about one quarter to one half the time of the conventional cutting method. This will reduce labour costs and speedup construction time (with the additional benefit of reducing any construction "overhead" costs such as the cost of maintaining a barge and crane presence and all other fixed costs that are maintained for the duration of the project).

(v) It is expected the welding process will also be quicker, which will also result in labour and construction overhead benefits. There will be some set-up time required (approx. ½ hour) for the PACW; but once working the continuous welding process is more efficient than manual stop-start welding.

(vi) Less cuts of the pile and the overall increased efficiency of the automated cutting and welding will reduce the consumption, and therefore cost of consumable items such as gas, welding wire (stop starts increase problems with wire and tips) and grinding discs.

(v) The PACW eliminates many safety issues normally associated with manual cutting and welding (burns, fume inhalation, noise from metal grinding, airborne grinding materials, repetitive strain from uncomfortable weld positioning, and fatigue). The operator will be able to stand back from the machine when it is cutting or welding (except to the extent that a small amount of manual cutting and welding may still be required). (vi) The PACW track assembly and machine can be assembled and operated by one person.

(vii) An advantage of the PACW (over other automated technology) is the track assembly which facilitates a horizontal track set up around a raked pile.

It will be readily apparent to persons skilled in the relevant arts that various modifications and improvements may be made to the foregoing embodiments, in addition to those already described, without departing from the basic inventive concepts of the present invention. For example, in the described embodiment the PLC 40 is carried on-board the PACW, housed within the PACW casing. However a suitable programmable data processing device could just as readily be located remotely from the device, transmitting control signals to the device via a wireless data communications channel. Therefore, it will be appreciated that the scope of the invention is not limited to the specific embodiments described.

Claims

1. A programmable automated cutter/welder apparatus for cutting and/or welding a hollow cylinder, the apparatus comprising: a head assembly for cutting and/or welding a wall of the cylinder; an actuator assembly mechanically coupled to the head assembly for moving the head assembly relative to the wall of the cylinder; a motorised carriage for carrying the actuator assembly and head assembly around the circumference of the cylinder so as to cut and/or weld the wall of the cylinder around a section through the wall that can be of elliptical shape; a support structure adapted to be affixed to the cylinder to provide a path on which the motorised carriage can travel around the circumference of the cylinder; and, a programmable data processing device operatively connected to the motorised carriage and the actuator assembly for controlling the motion of the motorised carriage and the head assembly wherein, in use, the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a desired cut and/or weld in the wall of the cylinder that follows the shape of the section through the wall.

2. A programmable automated cutter/welder apparatus as defined in claim 1 , wherein, in a cutting mode, the programmable data processing device is programmed to vary the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder.

3. A programmable automated cutter/welder apparatus as defined in claim 1 , wherein, in the cutting mode the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a cut that is substantially horizontal on an inner edge of the wall of the cylinder.

4. A programmable automated cutter/welder apparatus as defined in claim

2, wherein, in the cutting mode, the programmable data processing device also automatically maintains a predetermined distance between a cutting tip on the head assembly and the wall of the cylinder. 5. A programmable automated cutter/welder apparatus as defined in claim 1 , wherein, the actuator assembly comprises a first linear actuator for moving the head assembly horizontally in the direction of an X-axis, and a second linear actuator for moving the head assembly vertically in the direction of a Z-axis. 6. A programmable automated cutter/weider apparatus as defined in claim 1 , wherein, each linear actuator is driven by respective first and second stepper motors, the linear actuators converting the rotation of the stepper motors into a linear movement.

7. A programmable automated cutter/welder apparatus as defined in claim , wherein, the motorised carriage is driven by a third stepper motor along a

P-Axis at a programmable speed.

8. A programmable automated cutter/welder apparatus as defined in claim

3, wherein, the apparatus further comprises a distance sensor, also carried on the motorised carriage and operatively connected to the programmable data processing device, for sensing the distance between the cutting tip of the head assembly and the wall of the cylinder wherein, in use, the distance sensor sends distance measurements to the programmable data processing device which in turn calculates and sends a compensation signal to the actuator assembly. 9. A programmable automated cutter/welder apparatus as defined in claim 1 , wherein, the head assembly is an interchangeable head which can be easily switched between a cutting tip in a cutting mode, and a welding gun in a welding mode.

10. A method of cutting and/or welding a hollow cylinder using a programmable automated cutter/welder apparatus, the method comprising the steps of: moving a cutting and/or welding head assembly relative to a wall of the cylinder using an actuator assembly mechanically coupled to the head assembly; carrying the actuator assembly and head assembly around the circumference of the cylinder using a motorised carriage so as to cut and/or weld a wall of the cylinder around a section through the wall that can be of elliptical shape; providing a path on which the motorised carriage can travel around the circumference of the cylinder using a support structure adapted to be affixed to the cylinder; and, controlling the motion of the motorised carnage and the actuator assembly using a programmable data processing device operatively connected to the motorised carriage and the actuator assembly wherein, in use, the speed of the motorised carriage and/or the position of the actuator assembly is controlled to produce a desired cut and/or weld that follows the shape of the section through the wall. 1 1. A method of cutting and/or welding a hollow cylinder as defined in claim 10, wherein, in a cutting mode, the programmable data processing device is programmed to vary the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder. 12. A method of cutting and/or welding a hollow cylinder as defined in claim 10, wherein the step of moving the head assembly involves moving the head assembly in the direction of an X-axis and/or a Z-axis wherein the distance of the head assembly relative to the wall of the cylinder can be varied.

13. A method of cutting and/or welding a hollow cylinder as defined in claim 10, wherein the step of controlling the motion of the motorised carriage involves moving the motorised carriage along a P-Axis at a programmable speed. 14. A method of cutting and/or welding a hollow cylinder as defined in claim 10, wherein in a cutting mode the step of controlling the motion of the motorised carriage and the actuator assembly involves varying the height of a cutting tip on the head assembly according to a formulated path as it moves around the circumference of the cylinder. 5. A method of cutting and/or welding a hollow cylinder as defined in claim 0, wherein in the cutting mode the speed of the motorised carriage and/or the position of the head assembly is controlled to produce a cut that is substantially horizontal on an inner edge of the wall of the cylinder.

16. A method of cutting and/or welding a hollow cylinder as defined in claim 10, claim 14 or claim 15, wherein an indexed counting system is utilised that decouples the cutting profile from the diameter and/or rake angle of the cylinder, making the system applicable for any diameter cylinder of a given rake angle or straight vertical orientation.

17. A method of cutting and/or welding a hollow cylinder as defined in claim 16, wherein an angular distance for the motorised carriage (P-Axis) is defined as a function of counts in a flat plane (P), and movement of the actuator assembly is controlled by calculating the rise and fail of Z-Axis distance counts in a synchronous fashion as a function of the counts to give a precise cut over the defined distance. 18. A method of cutting and/or welding a hollow cylinder as defined in claim 10, wherein the head assembly is an interchangeable head which can be easily switched between a cutting tip in a cutting mode, and a welding gun in a welding mode.

19. A track assembly for a programmable automated cutter/welder apparatus for cutting and/or welding a hollow cylinder, the track assembly comprising: a guide track to provide a path on which a motorised carriage of the programmable automated cutter/welder apparatus can travel around the circumference of the cylinder so as to cut and/or weld a wall of the cylinder around a section through the wall that can be of elliptical shape; a clamp arrangement adapted to clamp to an outer circumference of the cylinder; and a pair of elongate adjustable actuators for supporting the guide track, each adjustable actuator having one end mounted on the clamp arrangement and the other end connected to the guide track wherein, in use, the length of the adjustable actuators can be varied to adjust the angle at which the guide track is supported relative to the cylinder, 20. A track assembly as defined in claim 19, wherein the clamp arrangement is in the form of a clamp ring that clamps around the cylinder and acts as an anchor point for the rest of the track assembly.

21. A track assembly as defined in claim 20, wherein the clamp ring is formed in two halves which are joined together about the cylinder to form the complete clamp ring.

22. A track assembly as defined in claim 19, wherein the guide track is of circular shape and is formed in two halves.

23. A track assembly as defined in claim 22, wherein the guide track is an I- beam roiled into the desired shape. 24. A track assembly as defined in claim 23, wherein the guide track is supported on each adjustable actuator via a base plate.

25. A track assembly as defined in claim 22, wherein the base plates perform a dual function of connecting the two halves of the guide track together.

26. A track assembly as defined in claim 19, wherein the angle of the adjustable actuators can also be varied to enable the guide track to be positioned independently and without restriction on the vertical and horizontal axes relative to a position of the hollow cylinder.

27. A track assembly as defined in claim 26, wherein once the guide track is in position, a pair of adjustable struts is attached to the clamp arrangement and the guide track, perpendicular to the adjustable actuators, providing additional guide track support.