Blank holder for use in helical flight forming apparatus

Abstract

A blank holder (100) for a blank (80) for apparatus for use in the formation of a helical flight. In one embodiment the blank holder (100) comprises: a holder body (102), the holder body (102) having first and second sides (120, 130) with a slot (110) therebetween, body; the first and second sides of the holder body each having an inner wall (121, 131) which extends into the slot, each inner wall having side portions (122, 123, 132, 133) terminating at an inner gripping edge (125, 135); one of the side portions of the inner wall of the first side having a first contact surface (140) in the region of an upper part thereof and one of the side portions of the inner wall of the second side having a second contact surface (145) in the region of a lower part thereof, the first and second contact surfaces configured to contact respective main faces (86, 87) of the blank during formation into a helical flight. In another embodiment the blank holder (20) comprises: a holder body (22) comprising side sections (31, 32) on opposed sides of a slot (25), each side section (31, 32) having an insert (33, 34) associated therewith, each insert (33, 34) being removably mountable to a respective one of the side sections (31, 32) of the holder body (22) when in a mounted position.

Description

BLANK HOLDER FOR USE IN HELICAL FLIGHT FORMING APPARATUSTechnical 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 apparatus and a method of forming such flights and components, therefor.Background Art

[0002] In international patent application PCT publication number WO2017 / 156587, and European patent application 23179571.7, which will hereinafter be referred to in this patent specification as the Prior Art Patent Specifications, there is disclosed an apparatus for forming helical type flights. The contents of those specifications are incorporated in full into the present application by way of cross-reference. The Prior Art Patent Specifications which form part of the disclosure in this patent specification describe that apparatus in detail. The reference numerals used in the preamble of this patent specification are the same as those used to identify the parts and features described in the Prior Art Patent Specifications.

[0003] The inventor of the apparatus disclosed in the Prior Art Patent Specifications referred to is the same inventor of the matters disclosed in this specification. 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 field of invention to which this specification relates.

[0004] The apparatus 10, 210 described in the Prior Art Patent Specifications 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 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 performing position towards a formedposition 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 a plurality 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 there between.

[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. 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 effected by a separate or different drive.

[0007] As explained in the Prior Art Patent specifications, the movement or position adjustments of the support heads enables the edge regions of the blank to substantiallymove in accordance with the natural or true forming path of the flight helix which can be maintained during the forming process. In the case of the free movement arrangement described this occurs naturally. In the case where the movements or position adjustments are driven, the drives for these movements are controlled and synchronised so as to produce the desired helical flight profile.

[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.

[0009] This disclosure is concerned with a blank holder which can be used in apparatus for forming helical flights.Summary of Disclosure

[0010] In a first aspect embodiments are disclosed of a blank holder for a blank for apparatus for use in the formation of a helical flight the blank having opposed main faces, 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 of the blank so as to provide for opposed side edge sections the blank holder comprising: a holder body having a top and a base with a slot having a longitudinal axis extending from the top towards the base, the holder body having first and second sides with the slot therebetween, the slot having an open top end, a closed bottom end and first and second side openings between the first and second sides of the holder body; the first and second sides of the holder body each having an inner wall which extends into the slot, each inner wall having side portions which are inclined towards one another terminating at an inner gripping edge, the gripping edges being spaced apart with a gap therebetween; one of the side portions of the inner wall of first side having a first contact surface in the region of an upper part thereof and one of the side portions of the inner wall of the second side having a second contact surface in the region of a lower part thereof, the first and second contact surfaces configured to contact respective main faces of the blank during formation into a helical flight.

[0011] In certain embodiments the contacts are swept surfaces with a profile or contour which is in the shape of the helical profile being formed.

[0012] In certain embodiments the first and second contact surfaces are on the side portions of the inner walls adjacent to the second side opening of the slot.

[0013] In certain embodiments the first contact surface extends from the top end of the slot towards the bottom end terminating in a mid-region of the slot intermediate the top and bottom ends.

[0014] In certain embodiments the second contact surface extends from the bottom end of the slot towards the top end terminating in a further mid region of the slot intermediate the top and bottom ends.

[0015] In certain embodiments the gripping edges extend from the top end to the bottom end of the slot.

[0016] In certain embodiments the mid region and further region of the slot are spaced apart from one another.

[0017] In certain embodiments the first and second sides of the holder body each have an outer surface, there being a chamfered section in the outer surfaces which are adjacent one another.

[0018] In certain embodiments the first and second contact surfaces provide for a first group there being a second group on the other side portions of the inner walls.

[0019] In a second aspect embodiments are disclosed of a blank holder for a blank for use in a helical flight forming apparatus the blank having opposed main faces, 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, the blank holder comprising: a holder body having opposed ends with a slot through the holder body, the slot extending from one of the ends towards the other of the ends and terminating short of the other end, the holder body comprising side sections on opposed sides of the slot, each side section having an insert associated therewith each insert being removably mountable to a respective one of the side sections of the holder when in a mounted position, each insert having a gripping region, the gripping regions, when the inserts are in the mounted position being configured so as to hold one of the side edge sections of the blank therebetween when the blank is in an installed position.

[0020] In certain embodiments the gripping region of each insert extends into the slot when in the mounted position.

[0021] In certain embodiments the gripping region of each insert includes a contact edge which is adapted to contact a respective one of the main faces of the blank when the blank is in the installed position.

[0022] In certain embodiments each of the side sections includes an inner side facing the slot, each inner side section having a channel therein for releasably receiving one of the inserts therein when in the mounted position.

[0023] In certain embodiments each insert includes a mounting section which is receivable within the channel the gripping region projecting into the slot.

[0024] In certain embodiments the insert extends along substantially the entire length of the slot.

[0025] In certain embodiments one or both inserts extend along part of the slot.

[0026] In certain embodiments the gripping region is V-shaped when viewed in plan.

[0027] In certain embodiments the insert is circular when viewed in plan.

[0028] In certain embodiments this includes a locating arrangement for releasably retaining the insert in the mounted position.

[0029] In certain embodiments the locating arrangement comprises one or more magnetic elements operatively fitted to the inserts.

[0030] In a third aspect embodiments are disclosed of an apparatus for use in the formation of a helical screw flight from a blank having 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 of the blank so as to provide for opposed side edge sections the apparatus comprising: 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 from a preforming position towards a formed position in response to actuation of the drive, the first and second support heads being configured so as to be able to provide for a plurality of position adjustments including a lateral position adjustment whereby the first and second support heads can be displaced or moved laterally with respect to the main axis in a direction of respective lateral axes during formation of the helical flight and a rotational position adjustment wherein at least one of the first and second support heads can be rotatedabout a rotation axis which extends in a direction generally parallel to or coaxial with the main axis during formation of the helical flight, wherein the first and second support heads are in accordance with any one of those described earlier.

[0031] In a fourth aspect, embodiments are disclosed of a blank holder for use in helical flight forming apparatus, the blank holder comprising a blank holder body having top end, a bottom end and a slot extending from the top end towards the bottom end, the slot having a longitudinal axis extending from the top end towards the bottom end, the blank holder body including opposed sides on opposite sides of the slot, each side having an inner side wall section extending into the slot and terminating at a gripper edge section, the edge sections being spaced apart from one another with a gap therebetween the gripper edge sections when viewed in the direction longitudinal axis being one of a different number of profiles.

[0032] In certain embodiments each inner side wall section includes side portions which when viewed in the direction of the longitudinal axis are in inclined towards one another.

[0033] In certain embodiments the side portions have a profile which together are V- shaped and the gripper edge section comprises the inner most part of the side wall portions.

[0034] In certain embodiments the gripper edge section has a profile which is curved when viewed in the direction of the longitudinal axis.

[0035] In certain embodiments the side wall portions have a profile which terminates at an inner wall portion which extends therebetween and which extends in a plane parallel to the longitudinal axis, each inner wall portion having a tooth-like projection thereon which extends towards the longitudinal axis.

[0036] In certain embodiments the blank holder body is mounted for at least partial rotation about the longitudinal axis.

[0037] In certain embodiments the blank holder body is fixed against rotation about the longitudinal axis.

[0038] In certain embodiments the different profiles may be used with the blank holders described earlier.Brief Description of the Drawings

[0039] 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:

[0040] Figure 1 is an isometric view of a blank holder according to one embodiment viewed from one side;

[0041] Figure 2 is an isometric view of blank holder shown in figure 1 viewed from the other side;

[0042] Figure 3 and 4 are side elevations of the blank holder shown in figures 1 and 2;

[0043] Figures 5 to 10 are schematic views illustrating the blank holder shown in figures1 to 4 during formation of the helical flight;

[0044] Figure 11 is an isometric view of a blank holder according to yet another embodiment;

[0045] Figure 11 A and 11 B are schematic plan views of part of the blank holder shown in figure 11 ;

[0046] Figures 11 C, 11 D and 11 E are a modified form of the blank holder shown in figure 11 ;

[0047] Figure 12 is a view of the holder shown in figure 11 with a blank in an installed or fitted position;

[0048] Figure 13 is an isometric view of a blank holder according to yet another embodiment;

[0049] Figure 14 is a view of the holder shown in figure 13 with a blank in an installed or fitted position;

[0050] Figures 15 to 18 are isometric views of a holder according to yet another embodiment;

[0051] Figures 19 and 20 are isometric views of holders according to further embodiments;

[0052] Figure 21 is an isometric view of another type of holder;

[0053] Figure 22 is a schematic plan view of a blank holder according a further embodiment;

[0054] Figure 23 is a detail of the blank holder shown in figure 22;

[0055] Figure 24 is a plan view of the blank holder according to the embodiment shown in figures 22 and 23;

[0056] Figure 25 is a plan view of a blank holder according to another embodiment;

[0057] Figure 26 is a plan view of a blank holder according to another embodiment;

[0058] Figures 27 and 28 are schematic views of one type of blank holder;

[0059] Figure 29 is a side elevation of another type of blank holder; and

[0060] Figures 30 and 31 are views of a typical blank with which the holders described can be used.Detailed Description of Preferred Embodiments

[0061] Referring to figures 1 to 10 there is illustrated a blank holder 100 according to one embodiment which is suitable for use in apparatus for forming helical flights from a blank. Figures 30 and 31 illustrate one example of a blank 80. The blank 80 has two main faces 86 and 87, an outer peripheral edge 81 , a central hole 83 having an inner peripheral edge 89 with central axis A-A, and a spilt 85 extending from the outer peripheral edge 81 to the inner peripheral edge 89 of the blank so as to provide for opposed side edge sections 82, 84.

[0062] As best illustrated in figures 1 to 4 the holder 100 comprises a main body 102 having a top 103 and a base 104. A slot 110 extends through the main body 102 so as to provide for first and second sides 120 and 130 on opposite sides of the slot 110. The slot 110 has an open top end 112 and a closed bottom end 114 with a slot axis P-P (figures 3 and 4) extending longitudinally from the open top end 112 to the closed bottom end. The slot 110 has a first side opening 116 and a second side opening 118.

[0063] The first side 120 of the main body 102 has an inner wall 121 which extends into the slot 110. The inner wall 121 has side portions 122 and 123 which are inclined or taper towards one another terminating at an inner gripping edge 125. The gripping edges 125 and 135 are spaced apart with a gap therebetween. As shown in figures 5 to 10 a region of the blank 80 which is adjacent the edge section 82 is secured within the gap when the blank 80 is installed. One of the main faces 86 contacts one of the gripping edges 125 and the other main face 87 is in contact with the other gripping edge 135.

[0064] The second side 130 of the main body 102 has an inner wall 131 which extends into the slot 110. The inner wall 131 has side portions 130 and 132 which are inclined or taper towards one another terminating at an inner edge 135.The first and second sides 120 and 130 have first and second contact surfaces 140 and145 which together are configured to assist in the formation of the helical flight from blank 80. The first contact surface is on the side portion 122 of the inner wall 121 and the second contact surface 145 is on the side portion 132 of the inner wall 131 . As shown first contact surface 140 is disposed on an upper portion of inner wall 131. The contact surfaces 140 and 145 are close to one another in an intermediate region of the slot 110. The contact surfaces 140 and 145 are swept surfaces having a profile or contour in the shape of part of the profile of the faces of the helical flight being formed. That is to say the contact surfaces are complementary in profile or contour to the edge regions of the helical flight being formed. This is particularly the case at the maximum pitch of the subsequently formed helical flight. The contact surfaces are not flat or planar.

[0065] As shown, there are two further cooperating contact surfaces 140A and 145A. One group of contact surfaces is for use in the formation of left handed helical flights and the other of right handed helical flights.

[0066] The sides 120 and 130 have an outer wall surface which may be curved or partially circular. Each outer wall has a chamfered section 136. The holder 100 is, for example, adapted for use in apparatus of the type described in the Prior Art Patent Specifications. The operation of the holder 100 the apparatus is illustrated with reference to figures 5 to 10.

[0067] The blank holder 100 illustrated is suitable for use in apparatus for forming helical type flights the apparatus being in the form described in the preamble of this specification and in detail in the Prior Art Patent Specifications. As described the apparatus comprises two support heads which are arranged for movement away from one another in the direction of a main axis as well as lateral movement in the direction of lateral axes which extend laterally with respect to the main axis. In one embodiment the lateral axes are at about 90 degrees to the main axis. Furthermore, one or both of the support heads can rotate about a rotation axis which substantially parallel to or coaxal with the main axis. The blank holders 100 are each mounted to a respective one of the support heads and at least partially rotatable about a holder rotation axis P-P which is generally parallel with the lateral axes.

[0068] In operation the edge regions of the blank are initially installed in the slot 110 of respective blank holders 100. In figures 5 to 10 only one holder 100 is illustrated. As shown in figure 5 the edge region is positioned within the slot 110 in an initial preforming position with the inner peripheral edge of the central hole being adjacent the atop of the slot. Asshown the edge region extends through the openings 116 and 118 and the main faces 86 and 87 of the blank 80 are gripped by inner edges 125 and 135 and are spaced from the contact surfaces 140, 145, 140A and 145A.

[0069] A drive is then actuated so that the support heads, holder and side edges 85 and 86 are drawn or pulled apart in the direction of the main axis. During this forming movement the blank automatically adopts the natural or true helical profile in the case of the free movement embodiment or as a result of the controlled synchronised driven motion in the driven movement embodiment. In order to try and ensure that this natural helical profile is maintained as closely as possible the first and second support heads are mounted so that they can be laterally adjusted in the direction of the lateral axes and further the position of the second support head can be rotationally adjusted about a rotation axis. During the helical formation step each of the holders can partially rotate about axis P-P independently of one another.

[0070] Towards the end of the formation of the helical flight at or near the maximum intended helical flight pitch, part of the main face 86 of the blank bears against contact surface 140 and another part of the other main face 87 of the blank bears against contact surface 145. These contact surfaces have a profile which is about the same as parts of the helical profile being formed.

[0071] A conventional holder is illustrated in figures 27 and 28. During formation of the helical flight the main faces of the blank, in essence, only contact the gripping edges of the holder. While this arrangement is perfectly acceptable for the formation of most helical flights in some cases such as when the flights are relatively thin buckling or edge deformation can occur. By using holders of type of the present disclosure buckling can be inhibited.

[0072] Referring to figures 11 to 23 various embodiments of a further type of holder for use in apparatus for forming helical flights from a blank. Figures 30 and 31 illustrate one example of a blank 80. The blank 80 has two main faces 86 and 87, an outer peripheral edge 81 , a central hole 83 having an inner peripheral edge 89, and a split 85 extending from the outer peripheral edge 81 to the inner peripheral edge 89 of the blank so as to provide for opposed side edge sections 82, 84.

[0073] The holder 20 shown in figures 11 to 23 comprises a holder body 22 having first and second ends 23 and 24 with a slot 25 through the holder body 22 and extending from the first end 23 towards and terminating short of the second end 24. The slot 25 is opensided and open at the first end 23 but closed at the second end 24 and has a longitudinal central slot axis P-P which extends in a direction between the first and second ends.

[0074] The holder body 22 comprises a base section 26 at the second end 24 and two opposed spaced apart side sections 31 and 32 which extend from the first end 23 towards the second end 24 with the slot 25 being therebetween. The base section 26 has an outer surface which is curved when viewed in the longitudinal direction of the slot axis P-P. The side sections have outer side surfaces which may also be curved. The holder body 22 may be partially rotatable about axis P-P when used in apparatus of the type described in the Prior Art Patent Specifications. In other embodiments the holder body 22 may be fixed against rotation about axis P-P. As clearly illustrated in figures 11A and 11 B, the side sections 31 and 32 each comprise an inner side face 31A and 32A. Each side face 31 A and 32A have a channel 41 and 42 therein. The channels 41 and 42 extend substantially parallel with slot axis P-P.

[0075] The holder 20 further includes gripper inserts 33 and 34 which are releasably mountable to respective side sections 31 and 32 of the holder body 22. Each insert has a gripping region 35 and 36 with a contact edge or tip 37 and 38, which extends into the slot 25 when the insert is fitted to the holder body. The opposed tips 37 and 38 when fitted are spaced apart from one another with a gap G therebetween. The arrangement is such that a side edge region of a blank can be disposed within the gap G with the contact edges 37 and 38 in contact with or bearing against respective opposed main faces 86 and 87 of the blank.

[0076] In the embodiment shown in figures 11 C, 11 D and 11 E the movement of the gripper inserts 33 and 34 within the channels 41 and 42 is limited to axial movement in the direction of the longitudinal axis of the channels which is substantially parallel to axis P-P. As shown the channels 41 and 42 are generally diamond shaped with an opening 45 at an innermost edge. The grippers 33 and 34 are complementary in shape to the channels 41 and 42 and sized so as to be slidably received therein with the tips 37 and 38 projecting through the openings. Figure 11 E illustrates the gripper 33 partially inserted into channel 41 . Channel 42 does not have a gripper in it.

[0077] The gripper inserts 33 and 34 are mountable within the channels 41 and 42 in the inner faces of the side sections 31 and 32. In the embodiments of figures 11 to 14 the channels 41 and 42 are generally U-shaped when viewed in plan and are adapted to receivea complementary shaped mounting section 39 and 40 of an insert. The gripping sections are V-shaped so as to provide the edge 37 which abuts against a face of the blank.

[0078] The gripper inserts in figures 16 to 18 are smaller than these shown in figures 11 and 12 so that the gap G is larger thereby enabling the holder to accommodate blanks of different thickness.

[0079] In the embodiment of figures 16 to 18 the channels are V-shaped when viewed in the direction of axis P-P and the inserts are diamond shaped.

[0080] In the embodiment of figure 19 the channels are curved when viewed in the direction of axis P-P and the inserts are circular. As shown in figure 20 insert 33A extends along an upper part of the side edge 31 and insert 34A extends along a lower part of side section 32.

[0081] The holder may further include a locating arrangement 60 which is associated with the holder body and inserts to locate the insert in position on the side section of the holder body. In the embodiment shown in figure 15 the locating arrangement 60 comprises a series of magnetic elements 61 configured to retain the inserts in position on the sides sections of the holder body. As is apparent the inserts can be fitted to the holder by sliding one end of a gripper through into the channel from the upper end of the holder.

[0082] Figure 21 illustrates a further embodiment of holder 20. In this embodiment the holder is fixed against rotation.

[0083] The blank holder described provides for significant versatility in its use. Inserts can be readily replaced when they wear out without the need for providing a complete new holder. The holder body enables the use of different inserts for different applications. The inserts can be of different sizes so the gap for receiving the blank side edge section enables different thicknesses of blanks to be used. The properties of the materials from which the inserts can be formed may be different to the materials from which the holder body is formed. The inserts can be formed from a hardened material in order to provide for better wear.

[0084] Referring to figures 22 to 26 various embodiments of a first type of blank holders are illustrated and which are suitable for use in apparatus for forming helical flights from a blank. Figures 30 and 31 illustrate one example of a blank 80. The blank 80 has two main faces 86 and 87, an outer peripheral edge 81 , a central hole 83 having an inner peripheral edge 84 with a central axis A-A, and a split 85 extending from the outer peripheral edge 81to the inner peripheral edge 84 of the blank so as to provide for opposed side edge sections 82, 84.

[0085] Figures 27 and 28 illustrate one type of blank holder. The holder 20 is elongated in form having opposed ends. A slot 25 extends from one end 23 towards and terminating short of the other end 24. The slot 25 comprises opposed spaced apart sides 26 and 27 terminating at a spaced apart inner edges 36 and 37 so as to provide for a gap therebetween.

[0086] The blank holders are adapted to be mounted to or form an integral part of a support head 600 which is adapted to be mounted to apparatus for forming helical flights of the type for example as described in detail in the Prior Art Patent Specifications. One form of support head 600 is shown in figures 22 and 23. The blank holders may be mounted to the support head 600 when in an operative position. In one embodiment the holder may be mounted for at least partial rotation about axis P-P. In another embodiment it may be fixed against such rotation. In yet another embodiment the holder may form an integral part of the support head as shown in figures 22 and 23.

[0087] As best illustrated in figures 24 to 26 each of the sides 26 and 27 of the holder include an inner side wall 28 and 29 which extend into the slot 25.

[0088] Each side wall 28 and 29 include side portions 30, 31 , 32 and 33. Side portions 30 and 31 are inclined towards one another and terminate at an inner edge portion 34. Similarly side portions 32 and 33 are inclined towards one another and terminate at an inner edge portion 35. The inner edge portions 34 and 35 form gripping edges 36 and 37 configured to contact and grip or the main faces 86 and 87 at the side edge sections 82 and 84 of the blank 80.

[0089] The profile of the inner side walls 28 and 29 can vary dependent upon various properties of the blank 80. Examples of different profiles are illustrated in figures 24 and 26.

[0090] In the embodiment of figure 24 the inner side portions 30 and 31 as well as 32 and 33 are generally V-shaped defining the contact or gripper edges 36 and 37. This profile finds particular use for blanks formed from low friction metal such as polished stainless steel or high hardness materials such as wear resistant steel. The gripper edges 36 and 37 tend to inhibit the blank 80 from slipping out of the blank holders 20 during formation of the helical flight.

[0091] In the embodiment of figure 26 the side portions are similar in shape to that of figure 24 except that the contact or gripper edges 36 and 37 are curved. This arrangementis good for blanks of low to mid hardness such as general steel. It enables the blank to be gripped and relatively easy to extract from the holder.

[0092] In the embodiment of figure 25 the side portions 30, 31 , 32 and 33 are truncated with an inner wall 38 extending therebetween. A small tooth or spike 39 extends from the inner wall. The tooth or spike is sized so as to limit the depth of the indentation or penetration of the tooth into the surface of the blank.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] Where ever it is used, the word “comprising” is to be understood in its “open” sense, that is, in the sense of “including”, and thus not limited to its “closed” sense, that isthe sense of “consisting only of”. A corresponding meaning is to be attributed to the corresponding words “comprise”, “comprised” and “comprises” where they appear.Table of PartsHolder 100Holder Body 102Top 103Base 104Slot 110Open Top End 112Closed Bottom End 114First Side Opening 116 Second Side Opening 118 First Side 120Second Side 130Inner Walls 121 / 131Side Portions 122 / 123 / 132 / 133Inner Gripping Edge 125 / 135Slot Axis P-PFirst Contact Surface 140Second Contact Surface 145Chamfered Section 136Blank 80Main Faces 86 / 87Outer Peripheral Edge 81Hole 83Inner Peripheral Edge 84 Side Edge Sections 82 / 84 Holder 20Holder Body 22First End 23Second End 24Slot 25Slot Axis P-PSide Sections 31 / 32Inner Faces 31A / 32ABase Section 26Gripper Inserts 33 / 34Gripper Region 35 / 36Contact Edge / Tip 37 / 38Mounting Section 39 / 40Gap GChannels 41 / 42Opening 45Locating Arrangement 60Magnetic Elements 61Blank 80Main Face 86 / 87Outer Peripheral Edge 81Central Hole 83Inner Peripheral Edge 89Split 85Side Edge Section 82 / 84Blank Holder 20Blank Holder Body 22Top End 23Bottom End 24Slot 25Slot Axis P-PSides (Sections) (Portions) (Parts) 26 / 27Inner Side Wall Section 28 / 29Side Portions 30 / 31 / 32 / 33Inner Edge Portion 34 / 35Gripping Edges 36 / 37Inner Wall 38Tooth 39Blank 80Main Faces 86 / 87Outer Peripheral Edge 81Hole 83Inner Peripheral Edge 84Side Edge Sections 82 / 84Support Head 600

Claims

Claims1 . A blank holder (100) for a blank (80) for apparatus for use in the formation of a helical flight the blank (80) having opposed main faces (86, 87), an outer peripheral edge (81), 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 blank holder (100) comprising: i. a holder body (102) having a top (103) and a base (104) with a slot (110) having a longitudinal axis (P-P) extending from the top towards the base, the holder body (102) having first and second sides (120, 130) with the slot (110) therebetween, the slot (110) having an open top end (112), a closed bottom end (114) and first and second side openings (116, 118) between the first and second sides of the holder body; ii. the first and second sides of the holder body each having an inner wall (121 , 131) which extends into the slot, each inner wall having side portions (122, 123, 132, 133) which are inclined towards one another terminating at an inner gripping edge (125, 135), the gripping edges being spaced apart with a gap therebetween; iii. one of the side portions of the inner wall of first side having a first contact surface (140) in the region of an upper part thereof and one of the side portions of the inner wall of the second side having a second contact surface (145) in the region of a lower part thereof, the first and second contact surfaces configured to contact respective main faces (86, 87) of the blank during formation into a helical flight.

2. A blank holder according to claim 1 wherein the contact surfaces are swept surfaces with a profile or contour which is in the shape of the helical profile being formed.

3. A blank holder according to claim 1 or 2 wherein the first and second contact surfaces (140, 145) are on the side portions (122, 132) of the inner walls adjacent to the second side opening (118) of the slot (110).

4. A blank holder according to claim 1 , 2 or 3 wherein the first contact surface (140) extends from the top end of the slot towards the bottom end terminating in a mid-region of the slot intermediate the top and bottom ends.

5. A blank holder according to any one of claims 1 to 4 wherein the second contact surface (145) extends from the bottom end of the slot towards the top end terminating in a further mid region of the slot intermediate the top and bottom ends.

6. A blank holder according to any one of claims 1 to 5 wherein the gripping edges (125, 135) extend from the top end to the bottom end of the slot.

7. A blank holder according to claim 5 wherein the mid region and further region of the slot are spaced apart from one another.

8. A blank holder according to any one of claims 1 to 7 wherein the first and second sides of the holder body each have an outer surface, there being a chamfered section in the outer surfaces which are adjacent one another.

9. A blank holder according to any one of claims 1 to 8 wherein the first and second contact surfaces provide for a first group there being a second group on the other side portions of the inner walls.

10. A blank holder (20) for a blank (80) for use in a helical flight forming apparatus the blank (80) having opposed main faces (86, 87), an outer peripheral edge (81 ), a central hole (83) having an inner peripheral edge (89), and a split (85) extending from the outer peripheral edge (81) to the inner peripheral edge (89) so as to provide for opposed side edge sections (82, 84), the blank holder (20) comprising: a holder body (22) having opposed ends (23, 24) with a slot (25) through the holder body (22), the slot (25) extending from one of the ends (23) towards the other of the ends (24) and terminating short of the other end (24), the holder body (22) comprising side sections (31 , 32) on opposed sides of the slot (25), each side section (31 , 32) having an insert (33, 34) associated therewith, each insert (33, 34) being removably mountable to a respective one of the side sections (31 , 32) of the holder body (22) when in a mounted position, each insert (33, 34) having a gripping region (35, 36), the gripping regions (35, 36), when the inserts (33, 34) are in the mounted position being configured so as to hold a respective one of the side edge sections (82, 84) of the blank (80) therebetween when the blank (80) is in an installed position.

11. A blank holder (20) according to claim 10, wherein the gripping region (35, 36) of each insert (33, 34) extends into the slot (25) when in the mounted position.

12. A blank holder (20) according to claim 10 or claim 11 , wherein the gripping region (35, 36) of each insert (33, 34) includes a contact edge (37, 38) which is adapted to contact a respective one of the main faces (86, 87) of the blank (80) when the blank (80) is in the installed position.

13. A blank holder (20) according to any one of the claims 10 to 12, wherein each of the side sections (31 , 32) includes an inner side face (31 A, 32A) facing the slot (25), each inner side face (31 A, 32A) having a channel (41 , 42) therein for releasably receiving one of the inserts (33, 34) therein when in the mounted position.

14. A blank holder (20) according to claim 13, wherein each insert (33, 34) includes a mounting section (39, 40) which is receivable within the channel (41 , 42) with the gripping region (35, 36) projecting into the slot (25).

15. A blank holder (20) according to claim 13, wherein one or both of the inserts (33, 34) extend substantially along the entire length of the slot (25).

16. A blank holder (20) according to claim 13, wherein one or both of the inserts (33, 34) extend along part of the slot (25).

17. A blank holder (20) according to any one of the claims 10 to 16, wherein the gripping region (35, 36) is V-shaped when viewed in plan.

18. A blank holder (20) according to any one of the claims 10 to 16, wherein the insert (33, 34) is circular when viewed in plan.

19. A blank holder (20) according to any one of the claims 10 to 18, including a locating arrangement (60) for releasably locating the inserts (33, 34) in the mounted position.

20. A blank holder (20) according to claim 19, wherein the locating arrangement (60) comprises one or more magnetic elements (61) operatively fitted to the inserts (33, 34).21 . An apparatus for use in the formation of a helical screw flight from a blank having 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 of the blank so as to provide for opposed side edge sections the apparatus comprising: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 from a preforming position towards a formed position in response to actuation of the drive, the first and second support heads being configured so as to be able to provide for a plurality of position adjustments including a lateral position adjustment whereby the first and second support heads can be displaced or moved laterally with respect to the main axis in a direction of respective lateral axes during formation of the helical flight and a rotational position adjustment wherein at least one of the first and second support heads can be rotated about a rotation axis which extends in a direction generally parallel to or coaxial with the main axis during formation of the helical flight, wherein the first and second support heads are in accordance with any one of claims 10 to 20.

22. A blank holder (20) for use in helical flight, forming apparatus, the blank holder (20) comprising a blank holder body (22) having top end (23), a bottom end (24) and a slot (25), extending from the top end towards the bottom end the slot having a longitudinal axis (P-P) extending from the top end towards the bottom end, the blank holder body including opposed sides (26, 27) on opposite sides of the slot, each having an inner side wall section (28, 29) extending into the slot and terminating at a gripper edge (36,37), the gripper edges (36, 37) being spaced apart from one another with a gap therebetween the gripper edges when viewed in the direction of the longitudinal axis being one of the different number of profiles.

23. A blank holder according to claim 22 wherein each inner side wall section includes side portions (30, 31 , 32, 33) which when viewed in the direction of the longitudinal axis are inclined towards one another.

24. A blank holder according to claim 23 wherein the side portions (30, 31 , 32, 33) together are V-shaped and the gripper edge (36, 37) comprises the inner most part of the side wall portions.

25. A blank holder according to any of claim 23 wherein the gripper edge (36, 37) is curved when viewed in the direction of the longitudinal axis.

26. A blank holder according to claim 23 wherein side wall portions terminate at an inner wall portion (38) which extends between the side portions in a plane parallel to the longitudinal axis, each inner wall portion having a tooth-like projection thereon which extends towards the longitudinal axis.

27. A blank holder according to any one of the claims 22 to 26 wherein the blank holder body is mounted for at least partial rotation about the longitudinal axis.

28. A blank holder according to any one of the claims 22 to 26 wherein the blank holder body is fixed against rotation about the longitudinal axis.

29. A blank holder according to any one of claims 1 to 21 wherein the gripper edge or region is in accordance with any one of claims 24 to 26.

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