Throughout history not only were shoe styles changing but shoe structure itself was undergoing changes. If the first form of footwear was a single piece of hide or skin, nowadays the shoe is a very complicated structure comprising dozens of details. They may be classified into two groups: shoe bottom and shoe upper.
The sole is the main part of the bottom. There are three main properties which a sole should possess: resistance to wear, resistance to water, flexibility. Other properties, not perhaps so important but nevertheless certainly desirable are: the ability to “breathe”, the resistance to slip on wet surface. There are several materials available for use as soles. The most important are: leather, vulcanized rubber, polyurethane.
The heel is built of a great number of identical leather plates, lifts, which are fitted and pressed so tight that we don’t even notice that the heel is a compound detail. At present most shoes are made with moulded heels and soles. But there is a capron or wooden bush in the hollow moulded heel. As the heel is to be very firm, it is hard, that’s why we must protect our heel against this hardness. It is achieved by means of heel pad made of leather or cardboard and stuck on the heel part of the insole. The heel pad forms a kind of step which must be leveled so that we can walk comfortably. It is done by means of a sock which occupies the space from heel pad to toecap.
An integral part of the shoe is a shank, a narrow stripe of thick fabric or a thin metallic plate with a light bend. It supports the middle part of the foot and acts as a spring.
The insole covers these details and besides it has other functions and all of them are rather important. The insole is to absorb some 40 grams of perspiration which are daily given off by the foot, to hold the moisture which filters through the sole and so on and so forth.
If the details of the bottom are called to protect feet mainly fromexternal influences the upper in addition resists a destructive action of the foot. In walking the foot behaves as a compressed spring – all the time ittries to straighten itself. That’s why the parts of the upper must possess corresponding properties. Let’s have a look at some of them.
First, it is a toe cap. As a rule it is made of firm wear-resistant leather since it is the toe cap that is more often subjected to strong external influences. A stiff puff made of leather or special fabric with chemical impregnation keeps the shape of the toe cap and protects toes against injury. The vamp which covers the part of the foot from the first joints of the toes to the beginning of the instep wears out much faster than other details of the upper. That’s why it is cut and stitched with great carefulness. The better
class leather capable to withstand a repeated bend and cross elongation is used for vamps.
In addition to principal details of the shoe bottom and upper there is a number of internal and intermediate details such as lining, counter, interfacing and many others. These details along with the principal ones bear full load and form our comfortable and practical shoe.