This invention relates generally to a footwear component and its manufacture, and in particular to reinforcing shanks for a sole component of shoes and other footwear, as well as an apparatus and method for the production of those shanks.

A reinforcing shank is often incorporated into a shoe inner sole component to make the shoe rigid and shape stable in the shoe arch region. That is particularly in respect of shoes with high heels having steeply contoured arch regions, the shank preventing the arch region from distorting or collapsing under weight of the shoe wearer during a walking action. The shank extends lengthwise and substantially centrally of the rear of the shoe sole component, from just rearwardly of a joint between forepart and arch regions to the heel region. Those shanks are available in varying widths and generally have one or more longitudinally extending strengthening ribs pressed outwardly from a surface of the shank. Attachment of the shanks to the shoe sole component is generally by tacking, rivetting or stapling, and anchoring holes or slots are provided in the shanks for this purpose.

Reinforcing shanks are generally made from a high carbon steel material which is hardened and tempered, after being shaped into the desired contour, to provide added strength and resilience. This heat treatment adds to the cost of the shanks and ultimately shoes containing them. Cheaper shoes sometimes incorporate non-heat treated shanks made from mild steel cold rolled material, although such shanks suffer from a lack of strength and therefore may not adequately reinforce the arch region. Because of the large number of different shoes

manufactured at any one time, particularly shoes with varying arch region contours, a large stock of different reinforcing shanks must be maintained by shoe manufacturers. In addition, the shanks are usually shaped to the desired contour by pressing between die parts of die press apparatus. This requires relatively expensive, individual mating die parts between each different shank is contoured. As such, large die part inventories must also be maintained. This adds to overall shoe production costs. It is an object of the present invention to provide a simple, improved reinforcing shank.

It is a further object of the present invention to provide a relatively inexpensive reinforcing shank for shoes and other footwear.

Another object of the present invention is to provide a simple die part, and die press having die parts, for relatively inexpensively shaping reinforcing shanks and other articles.

A further object of the present invention is to provide a die part, and die press having die parts, which has increased versatility and can be readily adjusted to alter then shaping of reinforcing shanks and other articles.

With these objects in mind, the present invention provides in one broad aspect a reinforcing shank for a footwear sole component, including: an elongated shank body of strip material having opposed upper and lower faces; at least one strengthening rib portion extending longitudinally of the shank body, the at least one rib portion being raised outwardly from the upper face of the shank body so that an underlying groove is defined in the lower face; and, a series

of corrugations extending at least substantially transversely of the at least one rib portion and spaced apart along the at least one rib portion.

Preferably, the corrugations have a height which is only small compared to an overall height of the at least one rib portion above a plane of the shank body.

Preferably, the corrugations are of a smoothly, rounded shape in at least one embodiment.

Preferably, indentations are provided in spaced apart relation within the underlying groove. Those indentations extend across the bottom of the groove and deform the at least one rib portion so as to form the corrugations.

Preferably, the shank body has a respective flange portion extending along each side of the at least one rib portion, with a respective corner juncture being formed therebetween. Preferably, indentations are provided in spaced apart relation along those corner junctures between the at least one rib portion and flange portions.

Preferably, indentations are provided in spaced apart relation along at least one longitudinal edge of the shank body. Those indentations may be provided in the lower face of the shank body at each edge.

In another broad aspect, the present invention provides a die part for press shaping a strip or sheet of material, including: holding means for mounting the die part in a die press apparatus; and, a series of individual slip pieces having opposed side faces and at least one working edge face, the slip pieces being packed together side face-to-side face and held by the holding means so that the working edge faces together present a die press surface for engaging a strip or

sheet of material during a pressing operation, the slip pieces being individually shaped at the working edge face and positioned relative to one another to provide the die press surface with a desired profile having regard to the shape into which the material is to be pressed.

Preferably, each working edge face is generally rounded about an axis contained in the plane of the respective slip piece. In this way, with the slip pieces packed together, the working edge faces present a corrugated die press surface. 10 Preferably, the holding means includes a holding frame by which the slip pieces are packed and tightly held together, the holding frame being adjustable to release the slip pieces for shifting and removal thereof. Preferably, the holding frame has at least two walls with a holding recess formed therebetween and in which the slip pieces are located, the walls being relatively movable for clamping and unclamping of the slip pieces.

Preferably, the die part further includes a profiling member having a profiling surface against which the slip 20 pieces abut in order to relatively set the die press surface profile. Each slip piece preferably has a bearing edge face opposite the working edge face. The bearing edge faces then abut against the profiling surface and the slip pieces outstanding therefrom. The profiling member may be a profiling block removably located in the holding means.

In a further broad aspect, the present invention provides a press die for press shaping a strip or sheet of material, including a pair of the above die parts, the die parts being relatively movable toward and away from one

30 another and having die press surfaces which are at least

substantially complementary to one another in profile for mating with one another when moved together, movement of the die parts toward one another causing a strip or sheet of material positioned therebetween to be pressed into a shape conforming with the complementarily shaped die press surfaces.

The following description refers to preferred embodiments of the reinforcing shank, die press and die parts of the present invention. To facilitate an understanding of the invention, reference is made in the description to the accompanying drawings where the reinforcing shank and die parts are illustrated in those preferred embodiments. It is to be understood that the reinforcing shank and die parts are not limited to the preferred embodiments as hereinafter described and as illustrated in the drawings.

In the drawings:

Fig. 1 is a perspective view of a reinforcing shank according to a preferred embodiment of the present invention;

Fig. 2 is a different perspective view of the reinforcing shank in Fig. 1; Fig. 3 is a cross-sectional view of the reinforcing shank of Fig. 1 taken through section I-I.

Fig. 4 is a perspective view of a "female" die part according to a preferred embodiment of the present invention and used in the production of the reinforcing shank in Fig. 1;

Fig. 5 is a perspective view of one slip piece from the die part in Fig. 4;

Fig. 6 is a perspective view of a "male" die part according to a preferred embodiment of the present invention and used in conjunction with the "female" die part in Fig. 4 in the production of the reinforcing shank in Fig. 1; and,

Fig. 7 is a perspective view of one slip piece from the die part in Fig. 6.

Referring initially to Figs. 1 to 3, there is generally shown reinforcing shank 1 for a footwear sole component (not shown) . Shank 1 has elongated shank body 2 with upper face 3 and opposed lower face 4. One (as shown) or more (not shown) strengthening rib portion 5 extends longitudinally of body 2. That rib portion 5 is raised outwardly from upper face 3 so that underlying groove 6 is defined in lower face 4. As so far described, shank 1 is generally of conventional construction. However, shank 1 also has a series of corrugations 7, spaced apart along rib portion 5. Those corrugations 7 extend at least substantially transversely of the longitudinal extent of rib portion 5.

In one embodiment (as shown), rib portion 5 extends at least substantially entirely along shank body 2. Opposed end regions 8 are rib free in this embodiment. These end regions

8 are generally planar and provided with slots or other holes

9 for receiving fastening elements, such as tacks, rivets or staples to fasten shank 1 to a shoe sole component.

Rib portion 5 is of any suitable shape and in the embodiment shown is generally U- or C- shaped in cross section.

Corrugations 7 in rib portion 5 have a height which is only small compared to the height of the rib portion 5. Moreover, corrugations 7 are overall quite shallow and generally smooth or rounded (rather than angular) .

Corrugations 7 are produced by spaced apart indentations

10 provided in groove 6, rib portion material at indentations 10 being pushed out of the general plane(s) of rib portion 5. Indentations 10 are generally confined to the bottom region of

groove 6 so that corrugations 7 appear generally only at or adjacent the top of rib portion 5. Indentations 10 are of any shape and size and in one embodiment (as shown) are generally square or rectangular shaped in plan view. Adjacent indentations 10 are spaced apart a distance which is slightly greater than the distance each indentation 10 extends along groove 6. In one example, about 25 indentations are provided in a rib portion about 75 mm long.

Shank body 2 has respective flange portion 11 extending along each side of rib portion 5, with a respective corner juncture 12 being formed therebetween. Thus, where single rib portion 5 is provided in shank 1 (as shown), flange portion 11 extend laterally from opposite sides of rib portion 5 to longitudinal edges 13 of body 2. Where body 2 has two or more rib portions 5 (not shown) then flange portions 11 will again extend from outer most sides of rib portions 5 to longitudinal edges 13, whilst web portion(s) (not shown) extend between adjacent rib portions 5.

Flange portions 11 extend generally in the plane of body 2 , in one embodiment (as shown), although in other embodiments (not shown) they extend at a shallow angle to that plane, eg. flange portions 11 may be angled slightly downwardly relatively to upstanding rib portion(s) 5.

Juncture indentations 14 are provided in spaced apart relation along corner junctures between rib portion 5 and flange portions 11. Indentations 14 extend entirely along each juncture in one embodiment (as shown). Indentations 14 are provided in upper face 3, and are arranged in transverse lines containing indentations 10. Indentations 14 are also of any shape and size but, in one embodiment (as shown), are

generally triangular shaped in plan view, with one side extending along the juncture and the other sides converging outwardly of the respective junctures away from rib portion 5.

In one embodiment (as shown), indentations 14 are sufficiently deep, particularly immediately adjacent rib portion 5, to create corresponding slightly raised regions on lower face 4. Those raised regions are generally rounded in shape.

Edge indentations 15 are provided in spaced apart relation along one or both longitudinal edges 13. Indentations 15 extend along each edge 13 in one embodiment (as shown) and, again, are arranged in transverse lines with indentations 10 and 14. Indentations 15 are provided in lower face 4 at edges 13.

Shank body 2 may be straight, although in one embodiment (as s own), is longitudinally curved in conformity with an arch contour of a shoe sole component. In this embodiment, shank body 2 is curved so that rib portion 5 is located on the "inside" of the shank curvature. Shank 1 is composed of a ribbon of metal, such as steel. The steel is mild steel or high carbon steel in alternative embodiments. The ribbon material has a thickness of about 1 to 1.5 mm in one embodiment (as shown). That material may be heat treated, by hardening and tempering. Alternatively, the inclusion of corrugations 7 may provide shank 1 with sufficient stiffness to make heat treatment unnecessary in many applications. That in turn provides cost savings in shank production. Other materials can be used for shank 1. In one embodiment, shank 1 is formed from flat metal

strip material by pressing that material in a press die comprised of a pair of mating or complementary die parts, although it should be appreciated that other methods of manufacture may be equally suitable.

One such press die is shown in Figs. 4 to 7, and includes "female" die part 16f and "male" die part 16m, shown separately in Figs. 4 and 6 respectively. Each die part 16f, 16m, includes holding assembly 17 for mounting respective die part 16f, 16m in a press die apparatus (not shown), and a series of individual slip pieces 18 secured together in holding assembly 17.

Each holding assembly 17 has frame 19 by which slip pieces 18 are packed and held. Frame 19 tightly holds slip pieces 18 together in their position or relationship in this embodiment, but is also adjustable to release pieces 18 for shifting or removal from die part 16f, 16m. In effect, frame 19 releasably clamps respective slip pieces 18 together into a pack.

Each holding frame 19 defines recess 20 into which slip pieces 18 are packed. To that end, frame 19 includes walls 21 about recess 20 and which abut slip pieces 18 to hold them together. In one embodiment (as shown) slip pieces 18 are clamped between at least two walls 21, at least one wall 21 being selectively movable for clamping and unclamping of slip pieces 18. In this embodiment, at least one wall 21 is also adjustable to vary the size of recess 20 and thus the number and/or size of slip pieces 18 that can be packed therein.

In one embodiment (as shown), four walls 21, 22 are provided in each holding frame 19, being a pair of opposed end walls 21 and a pair of opposite side walls 22 arranged into a

box configuration forming rectangular recess 20. Slip pieces 18 are arranged so as to each extend across recess 20 between side walls 22 and extend side wall-to-side wall between end walls 21. In this way, side walls 22 act to hold pieces 18 against relative lateral shifting and end walls 21 press pieces 18 together. In this embodiment, at least one end wall 21 is movable for clamping and unclamping of slip pieces 18 therebetween. Movable end wall(s) 21 are located by a screw thread adjustment mechanism 23. It should be appreciated that other wall numbers and configurations are possible in alternative embodiments, and may depend on the shape of slip pieces 18.

Each holding assembly 17 mounts respective die part 16f, 16m, in a press apparatus by any suitable mounting means (not shown). That mounting may be releasable. By way of example, holding frame 19 is clamped in the apparatus and holes, slots, grooves, studs and/or other mounting facilities can be incorporated into holding frame 19 for that purpose.

Slip pieces 18 are shown in detail in Fig. 5 and 7 and have opposed side faces 24, working edge face 25 and bearing edge face 26. Those pieces 18 are packed in each holding frame 19 side face-to-side face so that working end faces 25 together present die press surface 27, between which surfaces 27 shanks 1 are pressed.

Slip pieces 18 are all of the same general shape and size, although it will be appreciated that working edge faces 25 will alter in accordance with the desired press surface profile. Generally, each slip piece 18 is planar and quadrangular, so as to be "title" like in one embodiment (as shown) . In one example used in the exemplary application,

each piece 18 is about 3 mm thick and about 40 mm long by about 20 mm wide.

Working edge faces 25 providing press surfaces 27 are of any suitable shape having regard to the desired press surface profile. By way of example, in the forming of reinforcing shank 1. Working edge faces 25 of at least some slip pieces 18 of die part 16f will have rib forming recess 28, whilst working edge faces 25 of at least some slip pieces 18 of die part 16m will have complementary rib forming protrusion 29 for mating with a respective recess 28.

Each working edge face 25 is generally rounded about an axis contained in the plane of slip piece 18. As a result of this rounding, slip pieces 18 together in a pack tend to present a corrugated die press surface 27 and it is this rounding that leads to formation of corrugations 7 in rib portion 5 of reinforcing shank 1. In that regard, the rounding of working edge faces 25 causes only a narrow linear region of each working edge face 25 to actually contact and press against a strip of material being shaped, and it is along these regions that at least some of indentations 10, 14 and 15 are formed. Because the narrow regions are spaced apart from one slip piece 18 to the next, a corrugation effect is achieved.

Slip pieces 18 are composed of any suitable material, such as tool steel.

Each die part 16f, 16m further includes profiling member

30 having profiling surface 31 against which slip pieces 18 abut in order to relatively set press surface profile.

Bearing edge faces 26 abut profiling surface 31 and slip pieces 18 outstand therefrom. When slip pieces 18 are of the

same general size then they generally reproduce profiling surface 31 on press surface 27. Depending on profiling surface shape, adjacent slip pieces 18 are arranged with their side faces 24 either completely face-to-face or partially offset. Thus, in one embodiment (not shown) profiling surface 31 is planar so that slip pieces 18 are side face-to-side face and press surface 27 is also planar. In other embodiments (as shown), profiling surface 31, is non-planar so that adjacent slip pieces 18 are offset and non-planar press surface 27 is provided. In producing curved reinforcing shanks 1, profiling surface 31 is longitudinally curved to form a longitudinally curved press surface profile.

Each profiling member 30 is in the nature of a block removably located in holding frame recess 20 beneath slip pieces 18.

Walls 21, 22 of holding frame 19 secure each profiling member 30 in position relative to slip pieces 18. Being removable, profiling members 30 can be easily replaced when a change in press surface profile is required. This is particularly advantageous in the exemplary application since profiling members 30 can be simply substituted, and otherwise the same die parts 16f, 16m used, to form reinforcing shanks of different contours.

Each profiling member 30 is formed from any suitable material including wood, aluminium and plastic.

Die parts 16f, 16m can be used in a conventional die press apparatus to produce reinforcing shanks as will be well appreciated by those skilled in the relevant art. A pair of these die parts 16f, 16m (as shown) replace conventional "one piece" die parts.

Die parts of the present invention can be substantially used to press form reinforcing shanks of different contours. Because only a relatively inexpensive profiling member need be substituted to vary the shank profile, the cost of producing and stocking die parts for producing different shanks may be minimised.

Although the die press and die parts of the present invention have been described and illustrated with reference to the production of reinforcing shanks, it should be appreciated that they may have much wider application. In that regard, the die press and die parts may be suitable for producing other articles, from either strip or sheet material, with appropriate profiling of the press surfaces.

Finally, it is to be understood that various modifications and/or additions may be made to the reinforcing shank, die part, and die press without departing from the ambit of the present invention as defined in the claims appended hereto.