Method and insert for manufacturing multi-density shoe soles

Abstract

A method for manufacturing a multi-density shoe sole is described, the method incorporates repeated injections of sole material onto a shoe upper mounted on a last and placed in a mould. The mould has an injection chamber, moveable side frames, a vertically moveable bottom piston and a shoe sole shaping insert which is placed in the mould prior to a first injection and removed from the mould after said first injection and prior to a second injection. The entire body of the shoe sole shaping insert is placed inside the injection chamber during the first injection. The shoe sole shaping insert acts as a dummy during the first injection, and leaves after its removal a cavity which in a later injection step is filled with another sole material, either another colour or another density. Also disclosed is an insert used in a mould for injection moulding of shoe soles.

Description

Background technique

[0001] The soles manufactured by the injection molding process have different densities. A single density sole is a sole made of only one material (eg, one type of polyurethane). Dual density soles can be made from two different types of polyurethane, each polyurethane having different properties with regard to eg hardness and impact absorption. Since the manufacture of injected shoe soles in the late 1960's, technical solutions on how to manufacture multi-density shoe soles have been widely described in the patent literature. Typically, multi-density soles consist of two or three layers lying on top of each other and extending longitudinally from heel to toe. DE4114088C1 describes a method and a device for manufacturing three-density shoe soles. The mold consists of two movable side frames, a bottom male mold and a profile plate. The profile plate is a removable part of the mold and is placed on the vertically extending edge of the bottom male mold pr...

Examples

Embodiment Construction

[0028] figure 1 The finished product of the invention is shown, a shoe 1 manufactured with a multidensity sole 3 according to the method of the invention. In this preferred embodiment, the sole consists of a midsole 4, a heel cap 5 and an outsole 6, usually a TPU outsole. Posts 7 and 8 in the lower heel 9 are provided to stabilize the foot during walking. In the upper heel portion 10, the heel cap 5 ensures a firm grip 180 degrees around the wearer's heel. In order to ensure this firm grip, the heel cap 5 is composed of a polyurethane having a higher density than that used for the midsole 4 . Thus, instead of using only one type of polyurethane for the midsole 4 and the heel cap 5, polyurethanes of different densities are used to achieve different sole properties at different locations. figure 2 showing the sole 3 without the upper 2, image 3 The heel cap 5 is shown as a separate part of the sole. As will be explained later, the heel cap is initially produced in a first...

Background technique

[0001] The soles manufactured by the injection molding process have different densities. A single density sole is a sole made of only one material (eg, one type of polyurethane). Dual density soles can be made from two different types of polyurethane, each polyurethane having different properties with regard to eg hardness and impact absorption. Since the manufacture of injected shoe soles in the late 1960's, technical solutions on how to manufacture multi-density shoe soles have been widely described in the patent literature. Typically, multi-density soles consist of two or three layers lying on top of each other and extending longitudinally from heel to toe. DE4114088C1 describes a method and a device for manufacturing three-density shoe soles. The mold consists of two movable side frames, a bottom male mold and a profile plate. The profile plate is a removable part of the mold and is placed on the vertically extending edge of the bottom male mold pr...

Examples

Embodiment Construction

[0028] figure 1 The finished product of the invention is shown, a shoe 1 manufactured with a multidensity sole 3 according to the method of the invention. In this preferred embodiment, the sole consists of a midsole 4, a heel cap 5 and an outsole 6, usually a TPU outsole. Posts 7 and 8 in the lower heel 9 are provided to stabilize the foot during walking. In the upper heel portion 10, the heel cap 5 ensures a firm grip 180 degrees around the wearer's heel. In order to ensure this firm grip, the heel cap 5 is composed of a polyurethane having a higher density than that used for the midsole 4 . Thus, instead of using only one type of polyurethane for the midsole 4 and the heel cap 5, polyurethanes of different densities are used to achieve different sole properties at different locations. figure 2 showing the sole 3 without the upper 2, image 3 The heel cap 5 is shown as a separate part of the sole. As will be explained later, the heel cap is initially produced in a first...

Images