Abstract: The invention relates to a mould for producing soles of footwear, and to the sole produced by said mould, which includes a moulding surface consisting of a plurality of recesses and projections forming protuberances, inside the sole, that compress and bend during the footstep, where the projections are inclined in relation to the surface of the footstep, said projections being designed and separated such that they are formed only by moulding, since it is not possible to insert a machining tool in the separation between said projections nor is it possible to machine the recesses between the projections.

Abstract: Valve and method for using it to insert a gas and punch orifices in plastic in molds used for making hollow footwear soles. The valve is linearly actuated, includes a helical spring and a stop such that the valve body head seals against a seat in the valve casing. Its configuration is thus simple, inexpensive and reliable, while the method is efficient as it is performed during the processing cycle of the plastic.

Abstract: The present invention consists in an injection method in which a material is injected which serves as the connection between the upper and the sole of the shoe, the mould used for this purpose and the shoe thus obtained in such a manner that the membranes of the breathable type incorporated in said shoe are not damaged.

Abstract: Valve and method for using it to insert a gas and punch orifices in plastic in moulds used for making hollow footwear soles. The valve is linearly actuated, includes a helical spring and a stop such that the valve body head seals against a seat in the valve casing. Its configuration is thus simple, inexpensive and reliable, while the method is efficient as it is performed during the processing cycle of the plastic.

Abstract: Footwear sole comprising a top half with hollow vertical configurations and a bottom half, wherein said configurations are filled to at least half of their volume with a shock-absorbing plastic material to absorb as great a range of possible loads with a simple and easily adjustable configuration.

Abstract: The present invention relates to flexible footwear that comprises flexing means, either in the sole or in the upper, or in both, and said means in turn comprise a groove placed transversely and 5 recovering means placed transversely to said groove such that, when the footwear flexes along the groove, the action of said recovery means cause the footwear to recover, promoting recovery of the initial form of the footwear upon completion of each step, and thereby enhancing walking comfort.