MODIFIED SOLE FOR THONG FOOTWEAR OR SANDALS, MOULD AND METHOD FOR MAKING THE SAME

DESCRIPTION The invention relates to thong footwear, i. e. flat or clog-shaped footwear, whose upper is made of two strips which are connected and divaricated in the form of a V, the frontally arranged vertex of which terminates with an extension centrally inserted in the front portion of the bottom of the item of footwear; this extension is fitted into the space between the hallux and the immediately adjacent toe when worn on the foot. The invention also relates to sandals, of the type known as"lace-ups", whose upper, which is wrapped around the foot and the ankle, is formed by strips or laces which are fastened perimetrally to the bottom of the item of footwear.

Both types of footwear are made of injection moulded synthetic resin by means of appropriate moulds. The invention also relates to a particular modification of the moulds usually employed and the method for obtaining the aforesaid items of footwear employing the mould.

In the prior art, after making the bottom of the item of footwear with the specific passing hole in the required position, the thong element is inserted in the hole and fastened inside the hole itself on the thickness of the bottom or to the lower side of the bottom on which an undersole will be applied. This method is similar for"lace-up"sandals in which each single strip or face is fastened to the bottom; this arrangement implies separate and subsequent construction and assembly phases, i. e. the bottom, the possible undersole and the strips of the upper are separately moulded and the terminal (s) of the upper are manually inserted and fastened in the hole (s) arranged on the bottom. Finally, the undersole, intended to come into contact with the ground, is applied.

Evidently, the first disadvantage in making the footwear described above is in that a specific manual intervention is required to insert and fasten the terminals of upper laces in the bottom, with all the related consequences.

A second disadvantage is in that this process is fragmented and laborious, with inevitable consequences in term of high production costs.

An additional disadvantage is related to the precarious fastening of the laces to the bottom, which determines a shorter life of the item of footwear.

Great advantages would derive from the possibility of obtaining an item of footwear, of the thong or sandal type, whose bottom is made by injection moulding with the lace terminals already connected to the bottom during such process. An additional advantage would derive from the fact that the necessary modification to the bottom mould would be reversible, meaning that the same modified mould could be used both for footwear bottoms of the new type and footwear bottoms of the traditional type.

Another considerable advantage would derive from the possibility of availing of a simple and repetitive process-method for making the footwear capable of maximising the possibility of industrialising the process and presenting elementary finishing operations, which can be completed very rapidly.

These objects and advantages are obtained according to the present innovation by footwear, of the thong or sandal type, consisting of a bottom, an undersole and an upper made of strips, in which the ends of said strips, intended to be fastened to said bottom are made integral by moulding both with the bottom and the undersole ; this result is obtained by modifying an injection mould consisting of two mould halves, of the traditional type, in which one mould half is intended to house an open shell forming the undersole in the bottom impression, and the other mould half has at least one mobile portion in the impression corresponding to that of the first mould half, which mobile portion determines a passing hollow zone, intended to receive, after removing said portion, a terminal of an upper forming a counter profile of the passage, so that the undersole shell, the bottom and the upper terminal can form a single body by injecting the moulding resin; this result is obtained solely by positioning the pre-moulded undersole shell in the first mould half and inserting each terminal of the upper in the passing hollow zone of the second mould half and injecting the synthetic resin in the traditional way.

Further features and advantages of the present invention will become clearer from the following description and from the attached drawings,

wherein: - figure 1 shows the total axonometric view of the mould ; - figure 2 shows an axonometric view of the two mould halves A and B ; - figure 3 shows a portion of the mould half B in which a small mobile mould component is visible on the bottom ; - figure 4 shows a portion of the mould half B in which the hollow opening resulting from the removal of the mobile mould components in figure 3 is visible on the bottom; - figure 5 shows a portion of the mould half B, in which a terminal of an upper (visible on the bottom) is inserted in the hollow opening resulting from the removal of the mobile mould component; - figure 6 shows a cross-section of the mould according to a perpendicular plane, which is orthogonal with respect to the floor level, presumable for footwear, ready to receive the moulding resin injection; - figure 7 shows a first item of footwear of the thong sandal type, made according to the invention ; - figure 8 shows a second item of footwear which is a variation of the thong sandal, made according to the invention; - figure 9 shows a third variation of the item of footwear of the thong sandal type, made according to the invention; - figure 10 shows a first item of footwear of the lace-up sandal type, made according to the invention; - figure 11 shoes a second item of footwear of the lace-up sandal type, made according to the invention.

Figures 7 and 10 show two types of footwear: specifically, figure 7 shows a thong sandal 7, and figure 10 shows a lace-up sandal 10. The thong sandal 7 presents an undersole 17, a bottom 27 and an upper 37; the upper 37 consists of two two-parted strips 39 and 40, which converge towards a terminal 38, the rear ends of said strips being laterally fastened to the lateral surface of the bottom. Ends 41 and 42 of the strip 40 are visible in figure 7.

The terminal 38 is inserted in the bottom 27.

Said first terminal 38 (figure 5) consists of a first section in the form of a thin tube 26 and continues forming a head 20, presenting an insert-shaped conformation with rounded edges superiorly terminating with a ring-shaped ridge 28, which externally extends the dimension; an additional terminal 29, consisting of a reversed U tube, is centrally arranged over the insert.

The lace-up sandal 10 presents an undersole 117, a bottom 127 and a plurality of laces from 101 to 106 which are wrapped on the foot or the ankle ; the laces present a free end; the opposite ends (from 111 to 116) are fastened to and inserted in the bottom. In both cases of footwear, the undersole is integral with the bottom, as are the terminals) inserted in the bottom, which are inserted integrally and irremovaby ; the undersole, bottom and fixed upper terminal assembly resulting from synthetic resin injection in the mould.

Said mould, illustrated and described with reference to footwear of the thong type 7, consists of two impressions and is made of two mould halves 11 and 21, whose internal sides perfectly form a counter profile according to a sinuous pattern, exactly corresponding to the pattern of the upper edge of the shell 17, forming the undersole of the footwear.

The first mould half 11 presents two symmetrically arranged recessed zones 2 and 4, which correspond exactly to the profile of the shell 17 forming the undersole or sole of the footwear; the second mould half 21 also presents two recessed zones 12 and 14 which are symmetrically arranged and exactly correspond to the bottom 27 and form the resting body of the footwear; the recessed zones 2 and 4,12 and 14, after perfectly closing the two mould halves 11 and 21, exactly form two hollow zones whose conformation corresponds to the bottom of the resulting footwear and thereby present a front zone 3 and 3a, corresponding to the sole of the foot, and a rear zone 6 and 6a, corresponding to the zone of the heel. In the front zones 3 and 3a, approximately in correspondence with the zones in which the space between the hallux and the adjacent toe is intended to be positioned, the mould half 21 presents a small mobile portion 1, forming the insert of a corresponding passing hollow zone 5; said mobile portion in the hollow opening is held

integral to the body of the mould half by means of a tie-rod 8, operated from the external face 9 of the mould half 21, by the head 18; loosening the tie-rod 8 easily permits the removal of the mobile portion 1, freeing the passing opening 5.

The conformation of the mould half 21, which is essentially a parallelepiped, presents four regulation relieves 22,23,24,25 arranged near the four internal angles, which when the mould is closed engage an equal number of counter profile indents arranged in the exactly corresponding position on the mould half 11, ensuring perfect regulation and ensuring that the internal openings of the mould perfectly correspond with the footwear to be moulded ; moulding is carried out. by injecting synthetic resin through the nozzles 16 and 19 in the mould half 21, in the recessed zone.

The method for obtaining the footwear according to the invention (footwear of the thong sandal type is described) consists in: positioning a half shell forming the undersole of the footwear in the corresponding hollow zone of the first mould half ; then easing-off the block rod of the insert in the recessed zone of the second mould half and removing the mobile portion, then passing the head block 20 of the terminal 38 of the upper inside the opening 5 from the outside of the mould half inwards making the upper project from the mould half ; and perfectly housing the block 20 in the opening 5 by pulling from inside the mould half outwards (according to the direction 30), so that the internal surface of the mould is perfectly equal to the upper dimension of the insert. After the assembly, the synthetic moulding resin is injected to fill the resulting opening from inside the undersole shell on the first mould half combined with the hollow zone of the second mould half ; the resin will expand also into the zone of the block, over the terminal of the upper, whereby incorporating the reverse U terminal, and make the upper irremovable after delivery.

The resulting footwear after delivery will present in the lower part an undersole shell, whose lower part may be embossed to form the surface for resting on the ground, said shell being possibly made using a different resin from that used to make the bottom, e. g. transparent and/or coloured; the shell

contains the bottom of the footwear strictly speaking inside, perimetrally. slightly projects from the bottom according to an upper pattern coinciding with the seam of the two mould halves which in this way conceal the possible delivery relief.

The footwear to be completed and made ready for use simply requires fastening the free ends of the upper by means of common anchoring means.

The advantages of an item of footwear obtained using the mould and the method according to the invention are clear. Such advantages materially relate to increased, more cost-effective industrialised production, as well as increasing reliability and life of the finished product.

Numerous variations are possible. For example, figure 8 shows an item of footwear in the form of a thong sandal 31, consisting of a shell, an undersole 47, a bottom 48 and an upper 51, consisting of two two-parted strips 52 and 53 whose rear ends are laterally fastened to the bottom and which converge frontally towards a terminal 49 inserted in the bottom 48; said first terminal consists of a first section in the form of a thin tube 53, continuing forming a head 50, presenting a parallelepiped block conformation with rounded edges. The terminal 49, when the footwear is moulded, is not connected to the upper 51. The upper and the terminal are connected by means of a button or rivet 33 only during the final assembly phase. The advantages of this constructive method are related to the greater simplicity, according to which the head 50 of the terminal 49 is inserted in the hollow zone 5 of the mould half 21 and to the fact that the upper is independent from the terminal.

An additional variation is shown in figure 9. The figure shows an item of footwear in the form of a thong sandal 43, presenting an undersole 57, a bottom 58 and an upper 61, which consists in two two-parted V-shaped strips 62 and 63, whose rear ends are laterally fastened to the bottom; the front convergence point of said strips 62,63 is connected by means of reversible means (a small lace) 64 to a reversed U-shaped terminal 59, whose upper part is connected to a parallelepiped block 60 with rounded edges, inserted in the bottom 58; the advantages of this constructive method are equivalent to

those described in relation to figure 8 and consist in the possibility of connecting a leather or fabric upper to the block inserted in the bottom.

Similarly, figure 11 shoes a lace-up sandal variation consisting again of an undersole 217, a bottom 227 and a plurality of terminal inserts (from 211 to 216) inserted with the usual constructive method in the bottom 227, the upper part of which is equipped with a reversed U-shaped terminals (from 159 to 164); a single lace 230 is passed through the reversed U-shaped terminals to wrap around the foot and the ankle. The advantages of the conformation of the item of footwear consist in making the finished bottom with undersole and attachments and in the possibility of selecting any type of lace. Another important matter is that the mould herein described, with one or more mobile insert portions not removed from their housings, can be used in a traditional way to deliver traditionally bottoms for footwear.

Numerous further changes are possible without departing from the concept of the invention itself anyway.

Sumarising, the invention consists in forming a passing zone, i. e. a passing hole 5, in the mould half 21, through which the component 26 or 38 or 53 or 59,60 or equivalent of the upper is passed externally or internally. The part of said component, which remains positioned in the opening formed by the two mould halves for injection moulding of the bottom of the footwear, is incorporated in the moulded bottom during the injection moulding process; on the other hand, the part of said component which is extended in the passing zone, i. e. in the passing hole 5 of the mould half 21 and projecting outwards, forms the thong 26, or 38, or 53, or 59 which is directly anchored to the bottom by means of the moulding process; the thong either belongs to, or is combined with, the upper 26,38,40 (figure 6) or 38,37,39,40 (figure 7) or 53,49,51,52 (figure 8) or 59,61,62,63 (figure 9), or other. In this way, all manual operations subsequent to moulding the bottom of the footwear for anchoring the thong component to the bottom are avoided, being these operations costly and not ensuring a certainly resistant anchoring.

The above also refers to lace-up sandal uppers as those described in figures 10 and 11 or other.