The strength of adhesion of a sole to its upper is determined by measuring the force needed to pull off the sole from the upper. A suitable last is placed inside the shoe, which is then placed on a straight edge acting as a fulcrum for applying load on the joint of the sole and upper. The maximum load the sole can withstand before coming off is determined and reported as the sole adhesion strength. This test can be carried out either at the heel or at the toe of the shoe.
The PROLIFIC Sole Adhesion Tester consists of a cantilever type load cell with a digital readout to measure and indicate the force applied at the junction of the sole or heel and the upper and a set of interchangeable toe pieces having different curvatures.
The load cell measures the force applied on the joint, which is indicated directly in kilograms on a digital readout with a peak force memory to indicate the maximum force applied before the failure of adhesion.
Five toe pieces of different curvatures are provided to enable toes and heels of different shapes and sizes to be tested. The length of arc of each toe piece, however, is the same to ensure that the force is applied only on a fixed length of joint. These are made from carbon steel for giving a long operational life. Any one of the toe pieces can be held in the equipment at one time.
The fulcrum on which the shoe is placed during the test has adjustable height to enable soles of different thickness to be tested. The height of the fulcrum is adjusted with the help of six spacer strips provided with the equipment.
The equipment is finished in grey hammertone stoving painting and bright chrome / zinc plating to give it a corrosion resistant finish.
|Diameter of hemispherical indenting tip||0 - 100 kg x 100 g|
|Curvatures of toe pieces||25, 30, 35, 40, and 45 mm|
|Length of contact arc||22 mm|