Control system and method for forming a helical flight

Abstract

An apparatus (210) and method for forming a helical screw flight from a blank (80) The apparatus (210) and method include a controller for controlling the operation of the apparatus, and which is configured to receive input data representative of the predetermined desired parameters of the helical flight to be formed, operate the drive to effect relative movement of the support heads (220, 230) to thereby form a flight from the blank (80), and, receive sensor data from one or more sensor (295). The or each sensor (295) senses if the helical flight is in an equilibrium state, and if not, then reverses the operation of the drive until an equilibrium state of the flight is sensed.

Description

CONTROL SYSTEM AND METHOD FOR FORMING A HELICAL FLIGHTTechnical Field

[0001] This disclosure relates generally to the manufacture of flights which are of a screw, helical or spiral shape. More particularly the disclosure is concerned with a control system for use with apparatus for forming such flights.Background Art

[0002] Any reference in this specification to prior art, or matter which is said to be known, is not to be taken as an acknowledgement or admission that such prior art or matter forms part of the common general knowledge in the technical field to which this specification relates.

[0003] In international patent application PCT Publication Number WO2017 / 156587 and European patent application 23179571.7, there is disclosed an apparatus for forming helical type flights. The contents of that specification are incorporated in full into the present application by way of cross-reference, and should be considered to form part of the disclosure in this patent specification to thereby describe that apparatus in detail. The reference numerals used in the preamble of this patent specification are the same as those used to identify parts and features described in the Applicant’s earlier patent specification.

[0004] The apparatus (10, 210) described in the Applicant’s earlier patent specification is for use in the formation of a helical screw flight from a blank (80) having an outer peripheral edge (82), a central hole (83) having an inner peripheral edge (84), and a split extending from the outer peripheral edge to the inner peripheral edge of the blank so as to provide for opposed side edge sections (82, 84). The apparatus comprises a drive (50, 250), first and second support heads (20, 220, 30, 230) configured to hold the blank (80) in the regions of the opposed side edge sections (82, 84), the first and second support heads (20, 220, 30, 230) being arranged for the relative axial movement or displacement with respect to one another during formation of the helical flight in a direction of a main axis (X-X) from a preforming position towards a formed position in response to actuation of the drive (50, 250). The first and second support heads (20, 220, 30, 230) are configured so as to provide for aplurality of a position adjustments including a lateral position adjustment whereby the first and second support heads (20, 220, 30, 230) can be displaced or moved laterally with respect to the main axis (X-X) in a direction of respective lateral axes (W-W, Y-Y) during formation of the helical flight and a rotational position adjustment wherein at least one of the first and second support heads (20, 220, 30, 230) can be rotated about a rotation axis (M-M) which extends in a direction generally parallel to or coaxial with the main axis (X-X) during formation of the helical flight.

[0005] The first and second support heads (20, 220, 30, 230) each include a main body (22, 222, 32, 232) and a holder (24, 224) operatively mounted thereto, the holders (24,224) configured to hold the blank (80) in the regions of the opposed side edge sections (82, 84). The holders (24, 224) are at least partially rotatable about respective pivot axes (P-P) which extend parallel to the respective lateral axes (W-W, Y-Y). As shown in figures 13 to 15 of this specification, the holders (24) comprise a one piece component including an elongated body (71) having opposed ends, a slot (72) extending from one end (73) towards and terminating short of the other end, the slot (72) comprising opposed V-shaped sides (76, 77) terminating at spaced apart inner edges (78), so as to provide for a gap or bight (79) therebetween. The first and second support heads include a housing cavity (79) in the main body (22, 222, 32 232) for receiving the holders (24, 224) therein. The holders (24, 224), include a curved outer wall and the housing cavity (79) comprises a complementary shaped curved inner wall enabling the relative rotation therebetween.

[0006] In one embodiment, the lateral movement of the first and second support heads (20, 220, 30, 230) in the direction of the lateral axes (W-W, Y-Y) is free movement absent of a drive, and the rotation of at least one of the support heads (20, 220, 30, 230) about the rotation axis (M-M) is also free movement absent of a drive.

[0007] In another embodiment, the lateral movement of the first and second support heads (20, 220, 30, 230) in the direction of the lateral axes (W-W, Y-Y) is driven movement effected by a drive, and the rotation of at least one the support heads (20, 220, 30, 230) about the rotation axis (M-M) is driven movement effected by a drive. Each driven movement is optionally affected by a separate or different drive.

[0008] The first and second support heads (20, 220, 30, 230) are operatively mounted to guides (25, 35, 225, 235) along which the first and second support heads can (20, 220,30, 230) track along in a direction of the lateral axes (W-W, Y-Y). The guides comprise guide rods (25, 35, 225, 235). The second guide (85, 235) further includes a support (38) configured to facilitate the rotation of the second support head (30, 230) about the rotation axis (M-M), such as for example of the type described above.Summary of Disclosure

[0009] This disclosure is concerned with a control system which can be used in apparatus for forming helical flights, and more particularly a control system which takes into account the effects of springback; that is, the property or characteristic of an elastic material which is subjected to a forming process to revert towards its original condition. Springback in an article may be influenced by factors such as the shape and / or thickness of material from which the article is formed.

[0010] The design of helical flights have a number of design parameters which include outside diameter, inside diameter, pitch, material thickness, material type and coverage.

[0011] The term “coverage” as used in the specification refers to the overall length of the flight or flight section in the axial direction.

[0012] In a first aspect, embodiments are disclosed of a controller for controlling the operation of an apparatus for forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, and, wherein the apparatus comprises: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive; and,a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and, wherein, the controller is configured to:(i) receive input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operate the drive to effect relative movement of the support heads to thereby form a flight from the blank; and,(iii) receive sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reverse the operation of the drive until an equilibrium state of the flight is sensed.

[0013] In certain embodiments, a sensor is associated with each support head.

[0014] In certain embodiments, the predetermined desired parameters includes an initial springback value of the helical flight to be formed.

[0015] In certain embodiments, the apparatus further includes: a measurement device configured to measure a coverage parameter of the flight being formed and provide measurement data representative thereof; and, wherein the controller is further configured to:(iv) receive measurement data from the measurement device to detect if the helical flight satisfies the desired coverage parameter, and if not, further operate the drive to reform the flight.

[0016] In certain embodiments, the predetermined desired parameters includes a coverage parameter of the helical flight to be formed, including any one or combination of: overall length; width; inner diameter outer diameter; pitch; helix direction (left hand or right hand); thickness; and,any other physical parameter of the formed helical flight.

[0017] In certain embodiments, the or each sensor includes any one or combination of: a strain gauge; a load cell, and, any other device to measure the stressed or equilibrium state of the flight being formed.

[0018] In certain embodiments, the measurement device includes any one or combination of: a translational axis encoder; and, any other device to measure the physical parameters of the flight being formed.

[0019] In certain embodiments, the interconnections between the controller, each sensor and / or the measurement device include any one or combination of wired or wireless interconnections.

[0020] In a second aspect, embodiments are disclosed of a method of forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, wherein the method controls the operation of an apparatus which includes: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive; and, a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and,the method including the steps of:(i) receiving input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operating a drive to effect relative movement of the support heads to thereby form a flight from the blank; and,(iii) receiving sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reversing the operation of the drive until an equilibrium state of the flight is sensed.

[0021] In certain embodiments, a sensor is associated with each support head.

[0022] In certain embodiments, the apparatus further includes: a measurement device configured to measure a coverage parameter of the flight being formed and provide measurement data representative thereof; and, wherein the method further includes the step of:(iv) receiving measurement data from a measurement device to detect if the helical flight satisfies a desired coverage parameter, and if not, further operate the drive to reform the flight.

[0023] In a third aspect, embodiments are disclosed of an apparatus for forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, and, wherein the apparatus comprises: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive;a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and, a controller, configured to:(i) receive input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operate the drive to effect relative movement of the support heads to thereby form a flight from the blank; and,(iii) receive sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reverse the operation of the drive until an equilibrium state of the flight is sensed.

[0024] In certain embodiments, a sensor is associated with each support head.Brief Description of the Drawings

[0025] Various aspects of the disclosure will become more fully understood from the following detailed description of preferred but non-limiting embodiments thereof, described in connection with the accompanying drawings, wherein:

[0026] Figures 1 to 3 are schematic isometric views showing different positions of an apparatus for forming a helical flight, according to a first embodiment of the invention;

[0027] Figure 4 is a schematic isometric view of a first support head which forms part of the apparatus shown in figures 1 to 3;

[0028] Figure 5 is a schematic isometric view of a second support head which forms part of the apparatus shown in figures 1 to 3;

[0029] Figure 6 is a modified form of the second support head shown in figure 5;

[0030] Figure 7 is an exploded view of the second support head shown in figure 6;

[0031] Figures 8 to 11 are various views of one of the support heads to indicate example optional positions of a sensor component thereon;

[0032] Figures 12 and 13 are schematic views of a blank which may be formed into a flight, suitable for use in the embodiment;

[0033] Figures 14 to 16 are schematic views of a holder or gripper component for use in the apparatus; and,

[0034] Figure 17 is a flow chart depicting the steps in a control system for forming a helical flight according to one example embodiment.Detailed Description of Preferred Embodiments

[0035] Figures 1 to 8 illustrate example embodiments of an apparatus or machine 210 for use in the formation of a flight of spiral, helical or screw shaped section, from a blank 80.

[0036] The flight is formed from the blank 80, as shown in figures 12 and 13. The blank 80 is a generally annular body in the form of a disc-like member, having an outer peripheral edge 81 , an inner or central hole 83, an inner peripheral edge 86, and with a split 85 from the outer to the inner edges 81 and 82, thereby providing for opposed side edges 82 and 84. In the embodiment shown, the blank 80 is generally circular, with an inner circular hole, the outer peripheral edge and the inner peripheral edge being circumferential edges. The blank 80 has opposed main faces 87, and, a control axis A-A.

[0037] The apparatus or machine 210 includes a main structure, frame or housing 212 which in the form shown comprises end sections 213 and 214 and an intermediate section 211 , which form a rigid structure. The structure or housing 212 includes a flight forming zone 217 between the end sections 213 and 214.

[0038] The apparatus 210 further includes a drive 250, which comprises a motor 253 arranged to power a linear actuator 251 in the form of a ballscrew 254. Power is transmitted from the motor 253 to the ballscrew 254 via a belt (not shown) which extends around pulleys 255 and 256. The ballscrew 254 includes a ballscrew nut 257 and a sleeve 258. Rotation of the ballscrew 254 causes linear movement of the nut 257 and sleeve 258 in the direction of main axis X-X.

[0039] The apparatus 210 further includes first and second support heads 220 and 230 which, in use, are adapted to hold the blank 80 in the region of the side edges 82 and 84.That is, the support head 220 is configured so as to hold the blank 80 in a side edge region of side edge 82, and, support head 230 is configured so as to hold the blank 80 in a side edge region of side edge 84. The terminology side edge region as used herein does not necessarily mean at the side edge but includes a region spaced from the side edge.

[0040] The lateral movement of the first and second support heads 220 and 230 of the apparatus 210, in the direction of the lateral axes, is driven by movement effected by respective drives. Further, the rotation of one of the support heads about the rotation axis is driven movement effected by a further drive. Each driven movement may be effected by a separate or different drive, the drives being synchronised so as to produce the desired helical flight. The drives may be in the form of motors.

[0041] The first support head 220 is an axially displaceable head arranged for displacement or movement in the direction of the main axis X-X in response to actuation of the drive. The second support head 230 is mounted to end section, so as to be inhibited from movement in the direction of the main axis X-X. The support heads 220 and 230 are best illustrated in figures 4 and 5. As mentioned earlier, in certain embodiments, the second support head could also be mounted for axial movement.

[0042] The first support head 220 is operatively connected to the drive 250 through a mounting 260, which includes a mounting plate 263 which is operatively connected to sleeve 258. The plate 263 is carried on guides 265 and 266 which, in the form shown, comprise guide rods 267 and 268 and associated sleeves 261 and 264. The guide rods 267 and 268 move through guide sleeves mounting 261 and 264, during axial linear movement of sleeve 258.

[0043] The first support head 220 is shown in detail in figure 4, and comprises a main body 222, which is operatively mounted to mounting plate 263 in the manner hereinafter described. The first support head 220 further includes a blank gripper or holder 224, which is adapted to grip or hold the blank 80 in the region of side edge 85. As shown, the blank holder 224 includes a gripper housing 215 secured to or formed as part of the main body 222. The blank holder 224 is adapted to grip the blank 80, and is in the form as shown and described in figures 19 to 21 of the Applicant’s earlier Patent Application, published as WO201 7 / 156587.

[0044] The blank holders 224 and 234 include a holder or gripper component 300, comprising a main body 71 which is preferably at least partially circular in plan, and which has a slot 72 extending from one end 73 of the main body, and, terminating short of the other end. The main body 71 has U-shaped sides 74 and 75 on opposite sides of the slot, with inner edges 76 and 77 and with a gap or bight 78 therebetween. The gripper component 300 is mounted to the housing 215, so as to be at least partially rotatable relative thereto about an axis P-P.

[0045] An edge section of the blank 80 is adapted to be positioned within the gap or bight 78 during formation of the helical flight. A pivotally mounted latch 270 is arranged so that it can overlie the gripper 224. The latch provides additional support for part of the holder 224 when it is under load.

[0046] The body portion 220 includes a ledge 221 , against which the blank can be located in an initial or pre-formed position. The position of the ledge 221 is adjustable laterally with respect to the main axis X-X. As shown, the ledge 221 is mounted within inclined groove or slot 223, for movement therealong. The ledge 221 can be locked in a desired position within the groove or slot 223 by lever 219.

[0047] The first support head 220 is arranged so that a lateral displacement of at least part thereof can be effected in a lateral direction with respect to main axis X-X. The lateral displacement is generally in the direction of lateral axis W-W. The lateral displacement can be effected in different ways. For example, as shown, the body portion 222 can be mounted for lateral displacement. To this end, the body portion 222 can be mounted on guides in the form shown, comprising guide rods 225 secured to mounting plates 295, which are secured to mounting plate 263. The rods 225 extend through apertures in the main body 222, so that the main body 222 can track along the rods 225 in the direction of axis W-W.

[0048] In another arrangement, the blank holder 224 may be mounted to the main body 222 so as to be displaceable in the direction of the lateral axis. In another arrangement, the lateral displacement could be a combination of the displacement of the main body 222 and the blank holder 224.

[0049] In this embodiment the lateral movement of the main body 222 of the first support head 220 is driven, and to this end, a drive motor 226 is mounted to plate 263. A drive belt(not shown) transmits power to screw 227 via pulleys 228 and 229. Rotation of the screw 227 causes movement of the main body 222 in a linear fashion therealong, in the direction of axis W-W.

[0050] The second support head 230 is similar in form to the first support head 220, and is described in detail in figure 48 of the Applicants earlier referenced patent publication. It comprises a main body 232, which is operatively mounted to end section 214 of the main structure or housing 212. The main body 232 is operatively connected to a support 238 which is mounted to the end section 214 through a shaft 233 and an associated bearing 231 (figure 52 of the Applicants earlier referenced patent publication) for rotation about an axis M-M which is parallel or co-axial with the main axis X-X. This is best illustrated in figure 52 of the Applicants earlier referenced patent publication. The support 238 is in the form of a plate member. The body portion 232 has a ledge 272, similar to ledge 221 of the first support head 220, against which the blank 80 can be located or seated. The second support head 230 includes a blank gripper or holder 234 which is adapted to grip or hold the blank 80 in the region of side edge 86. A latch 290, which functions in the same fashion as latch 270, is also provided.

[0051] In a similar fashion to the first support head 220, the second support head 230 is arranged so that a lateral displacement of at least part thereof can be effected. The lateral displacement is generally in the direction of axis Y-Y. Because the main body 232 can rotate about axis M-M, it will be appreciated that the angular position of lateral axis Y-Y will change. The lateral displacement can be effected in different ways. For example, as shown, the support head can be mounted for lateral displacement. To this end, the body portion 232 can be mounted on guides in the form of guide rods 235 secured to mounting plates 237, which are secured to support plate 238. The rods 235 extend through apertures in the body portion 232 in a similar fashion as described with reference to the first support head, so that the body portion can track along the rods 235. In another arrangement, the blank holder 234 may be mounted to the body portion 232 so as to be displaceable in the direction of the lateral axis. In another arrangement, the lateral displacement could be a combination of the displacement of the body portion 232 and the blank holder 234.

[0052] In this embodiment, the rotational movement of the main body 232 of the second support head 230 is driven, and to this end, as shown in figure 52, a drive motor 286 ismounted to a wall of end section 214. A drive belt (not shown) transmits power via pulleys 288 and 289. Rotation of the pulley 289 causes rotation of the main body 232 about axis M- M.

[0053] Furthermore, in this embodiment, the lateral movement of the main body 232 of the second support head 230 is driven, and, to this end, as shown in figure 46 of the Applicant earlier referenced patent publication, a drive motor 236 is mounted to plate 238. A drive belt (not shown) transmits power to screw 257 via pulleys 248 and 249. Rotation of the screw 257 causes movement of the main body 232 therealong in a linear fashion in the directions of axis Y-Y.

[0054] The various drives for effecting movement of the support heads are arranged to be driven in a synchronous fashion, so that a true helical flight can be formed. To this end, the drives are operatively connected to a control system, which enables communication and control of the drives. The control system includes an arrangement for taking into account the effect of springback.

[0055] Figures 6 and 7 illustrate a modified structure of the second support head shown in figure 5. The same numerals used to identify features in figure 5 are used to identify the same parts in figures 6 and 7.

[0056] Figures 6 and 7 also illustrate two types of sensors which may be used in the control system, whilst Figures 8 to 11 illustrate some alternative example positions of sensors located on one or both of the support heads 220 or 230.

[0057] The sensors may be in the form of a strain gauge 295, operatively fitted to the main body of the holder 234. The strain gauge is adapted to indirectly measure force by detecting the strain or deformation caused by the applied force.

[0058] The sensor may also be in the form of a load cell 297, operatively fitted to mounting plate. The load cell directly measures the force applied to it by converting it into an electrical signal.

[0059] As shown the strain gauge 295 is applied to the surface of housing 215. The load cell 297 is placed between the support head and the mounting.

[0060] One or both types of sensors may be used, and, may be placed in alternative positions as illustrated by way of example in Figures 8 to 11 . Whilst Figures 8 to 11 illustratethe sensors attached to the support head 230, it will be understood that the sensors may additionally or alternatively be placed on support head 220, in substantially similar and / or alternative positions. It will also be appreciated that one or more sensor 295 or load cell may be positioned on each or both support head 220, 230.

[0061] Figure 17 illustrates a flow chart depicting the various steps controlled by the system during formation of a helical flight for taking into account the effects of springback.

[0062] In a first step, various parameters of a selected or desired helical flight to be formed are input into the control system. The input may, for example, be performed via a keyboard, other input device, or, by uploading a file containing the parameters.

[0063] The various parameters of the desired helical flight may, for example, include the width of the helical profile formed from the blank, the inner diameter, the outer diameter, the pitch, the helix direction (left hand or right hand), the material thickness, the coverage, etc. Other desired parameters may additionally or alternatively be input into the control system, as will be appreciated by persons skilled in the art.

[0064] As mentioned earlier the term “coverage” as used in the specification refers to the overall length of helical flight or helical flight section being formed.

[0065] After the parameters of the desired helical flight or flight section have been inputted into the controller, the controller then processes this input information and determines the required movements of the drive motors, the support heads, and the other the components of the apparatus which may need to be moved, so as to form the desired helical screw from the blank.

[0066] For example, the controller calculates a measured coverage, which is the distance the support heads are displaced and may be required to be further displaced relative to one another in the direction of the main axis of the apparatus, in an initial stage of the helical flight or flight section formation.

[0067] To calculate this measured coverage, the controller receives an initial springback value which is used in the calculation of the measured coverage. The initial springback value may be a percentage of the desired coverage. The initial calculated measured coverage is the product of the initial springback value and the desired coverage of the helical flight or flight section to be ultimately formed. That is, the measured coverage is the initial springbackvalue multiplied by the desired coverage.

[0068] The apparatus is then operated to cause the relative displacement of the support heads to an initial position in which they are spaced apart by the measured coverage. In this initial position, the blank carried by the support heads may be in a stressed or non-equilibrium state.

[0069] The apparatus is then further operated so that the support heads are moved relative to and towards one another until the blank carried by the support heads is in an unstressed or equilibrium position.

[0070] One or more sensors are provided to sense the state of stress in the flight being held by the support heads.

[0071] After the flight is determined by the apparatus to be in the equilibrium state, the current coverage of the flight as measured by, for example, a translational axis encoder which forms part of the apparatus, may be compared to the desired coverage of the flight as specified by the input parameters which are inputted by an operator via the input device, or by an operator uploading a file.

[0072] If it is equal, the finished flight has been successfully formed. If it is not, a new springback value is calculated, which is used in the calculation of a new measured coverage.

[0073] The new springback value is calculated as a percentage of desired coverage divided by the desired coverage less the reverse travel distance of the support heads.

[0074] This new springback value is multiplied with the desired coverage to calculate a new measured coverage required for the flight to attain the desired coverage. The apparatus is operated to displace the support heads to the new measured coverage, after which the apparatus returns the support heads to a position in which the blank is in an unstressed or equilibrium state.

[0075] At this stage, the helical flight or flight section should be at the desired coverage based on the calculations. If not, the procedure is repeated.

[0076] The sensor(s) determine when the flight is in an unstressed or equilibrium state. This procedure may be fully automated.

[0077] An example of forming a flight is set out below. In the example, a flight is to beformed with a desired flight coverage of 100 mm and a theoretical springback of 115% (unknown initially).

[0078] In the following example, the helical flight to be formed includes, as one of its parameters, a coverage of 100 mm. It is this parameter which is used in the controller to determine the final desired helical flight. Although not known at the initial stage of formation, the helical flight has a springback value of 115% of the desired coverage. That is an order to obtain the desired coverage of 100 mm, the support heads holding the blank from which the desired helical flight is to be formed need to be displaced by a distance of 115% of desired coverage. When the helical flight returns to the unstressed state, it will have a coverage of 100 mm.

[0079] In an initial step a default or saved springback value is used to determine an initial measured coverage of the helical flight or section. This initial springback value is a percentage of the desired coverage. In this example, the initial springback value is 100% of the desired coverage. As such in this initial forming step the initial measured coverage will be 100 mm. During formation the support heads are moved along all of the axes referred to earlier.

[0080] After this initial formation step, the flight is under stress and not in the equilibrium state as the correct springback was not used to form the flight. The apparatus detects this using a sensor, to measure the stress on the flight in the support heads. The apparatus drives the support heads in reverse, and the stress in the flight is measured again. If the flight has not reached the equilibrium state yet, the process will continue. Once the flight is determined to be in a state of equilibrium, the current coverage of the flight is measured to be 87 mm, which is not the desired coverage of 100mm. Using the data that 13 mm of reverse travel was required to form the flight to attain the equilibrium state, the following formula on the machine determines the new springback value of this flight should be 115%. That formula is:

[0081] New Springback Value = Desired CoverageDesired Coverage-Reverse Travel Distance

[0082] The flight is re-formed with 115% springback (the apparatus pulls flight to 115%of desired coverage and then returns to 100% coverage). After forming, the flight is determined to be in the equilibrium state. As the current coverage of the flight is now 100 mm, which is the desired coverage, the finished flight has been produced.

[0083] In the foregoing description of preferred embodiments, specific terminology has been resorted to for the sake of clarity. However, the invention is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as “front” and “rear”, “inner” and “outer”, “above”, “below”, “upper” and “lower” and the like are used as words of convenience to provide reference points and are not to be constructed as limiting terms.

[0084] In this specification, the word “comprising” is to be understood in its “open” sense, that it, in the sense of “including”, and thus not limited to its “closed” sense, that is the sense of “consisting only of’. A corresponding meaning is to be attributed to the corresponding words ’’comprise", “comprised”, and “comprises” where they appear.

[0085] In addition, the foregoing describes only some embodiments of the invention(s), and alteration, modifications, additions and / or changes can be made thereto without departing from the scope and spirit of the disclosed embodiments, the embodiments being illustrative and not restrictive.

[0086] Furthermore, invention(s) have been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included withing the spirit and scope of the invention(s). Also, the various embodiments, e.g., aspects of one embodiment may be combined with aspects of another embodiment to realise yet other embodiments. Further, each independent feature or component of any given assembly may constitute an additional embodiment.

Claims

Claims1. A controller for controlling the operation of an apparatus for forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, and, wherein the apparatus comprises: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive; and, a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and, wherein, the controller is configured to:(i) receive input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operate the drive to effect relative movement of the support heads to thereby form a flight from the blank; and,(iii) receive sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reverse the operation of the drive until an equilibrium state of the flight is sensed.

2. The controller as claimed in claim 1 , wherein a sensor is associated with each support head.

3. The controller as claimed in claim 1 or 2, wherein said predetermined desired parameters includes an initial springback value of the helical flight to be formed.

4. The controller as claimed in any one of claims 1 to 3, wherein the apparatus further includes: a measurement device configured to measure a coverage parameter of the flight being formed and provide measurement data representative thereof; and, wherein the controller is further configured to:(iv) receive measurement data from the measurement device to detect if the helical flight satisfies the desired coverage parameter, and if not, further operate the drive to reform the flight.

5. The controller as claimed in claim 4, wherein said predetermined desired parameters includes a coverage parameter of the helical flight to be formed, including any one or combination of: overall length; width; inner diameter; outer diameter; pitch; helix direction (left hand or right hand); thickness; and, any other physical parameter of the formed helical flight.

6. The controller as claimed in any one of claims 1 to 5, wherein the or each sensor includes any one or combination of: a strain gauge; a load cell, and, any other device to measure the stressed or equilibrium state of the flight being formed.

7. The controller as claimed in any one of claims 1 to 6, wherein the measurement device includes any one or combination of: a translational axis encoder; and,any other device to measure the physical parameters of the flight being formed.

8. The controller as claimed in any one of claims 1 to 7, wherein the interconnections between the controller, each sensor and / or the measurement device include any one or combination of wired or wireless interconnections.

9. A method of forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, wherein the method controls the operation of an apparatus which includes: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive; and, a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and, the method including the steps of:(i) receiving input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operating a drive to effect relative movement of the support heads to thereby form a flight from the blank; and,(iii) receiving sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reversing the operation of the drive until an equilibrium state of the flight is sensed.

10. A method as claimed in claim 9, wherein a sensor is associated with each support head.11 . The method as claimed in claim 10, wherein the apparatus further includes: a measurement device configured to measure a coverage parameter of the flight being formed and provide measurement data representative thereof; and, wherein the method further includes the step of:(iv) receiving measurement data from a measurement device to detect if the helical flight satisfies a desired coverage parameter, and if not, further operate the drive to reform the flight.

12. An apparatus for forming a helical screw flight from a blank, wherein the blank includes an outer peripheral edge, a central hole having an inner peripheral edge, and a split extending from the outer peripheral edge to the inner peripheral edge so as to provide for opposed side edge sections, wherein the helical screw flight, when formed, includes predetermined desired parameters, and, wherein the apparatus comprises: a drive; first and second support heads configured to hold the blank at the opposed side edge sections, the support heads being arranged for relative axial movement with respect to one another during formation of the helical flight in a direction of a main axis between a preformed position and a formed position in response to actuation of the drive; a sensor associated with at least one of the support heads, the or each sensor configured to detect any force between a respective support head and a respective side section of the blank or flight, and provide sensor data representative of a stressed or equilibrium state; and, a controller, configured to:(i) receive input data representative of the predetermined desired parameters of the helical flight to be formed;(ii) operate the drive to effect relative movement of the support heads tothereby form a flight from the blank; and,(iii) receive sensor data from the or each sensor to sense if the helical flight is in an equilibrium state, and if not, then reverse the operation of the drive until an equilibrium state of the flight is sensed.

13. The apparatus as claimed in claim 12, wherein a sensor is associated with each support head.

Images