Various procedures are used to determine the resistance to scuffing of materials such as painted substrates, vinyl, leather, and luggage compartment mats. One such test utilizes an abraser manufactured by Teledyne Taber of North Tonawanda, New York. Such an abraser typically includes a specimen holder, a hold down ring, a rubber pad, and a clamp plate. Also, the abraser typically includes scuffing heads such as scuffing head 10 illustrated in FIGS. 1 through 3. As illustrated in the drawing FIGS. 1 through 3, the scuffing head 10 includes a hinged rear arm 12 which is designed to fit over a support 14 for the arm 12 and a wheel 16 of the abraser.
The hinge may be modified for different model abrasers, but when properly located, should position the scuffing head 10 so that it's vertical center line is a predetermined distance from a center pin of the specimen holder and in horizontal alignment with the center pin.
Typically, the painted specimen to be tested is cut from the larger part and conditioned in an air circulating oven having a controlled atmosphere including relative humidity. Then the abraser, including the scuffing head, is adjusted so that the scuffing head is perpendicular to the rotation of the specimen holder. Typically, this means that the scuffing head is placed on the abraser in place of wheels and weights normally used with the abraser. A weight is then placed on the scuffing head assembly. Then the abraser scuffs the test specimen for a predetermined number of cycles. After the predetermined number of cycles, the specimen is removed from the abraser and the arcs on the specimen that have paint removed therefrom are measured. From this measurement, the percent paint which is removed by the scuffing head is calculated. In this way, the resistance of paint to be removed from the substrate material is determined in a quantitative fashion.
The prior art scuffing heads such as the scuffing head 10 illustrated in FIGS. 1-3 have a number of disadvantages associated therewith. For example, for many specimens, a relatively large amount of weight must be used to bias the scuffing head against the rotating substrate in order to properly test the painted substrate. Also, because it is typically not possible to perfectly align the scuffing head relative to the rotating substrate, there is a danger of gouging the painted substrate as it rotates since the scuffing head may have a tendency to ride up on its edge. Also, the scuffing head of FIGS. 1-3 may not ride evenly on the surface of the rotating substrate due to misalignment between the scuffing head and the rotating substrate.
Another problem associated with such prior art scuffing heads is the expense associated with manufacturing a scuffing head such as the scuffing head 10 of FIGS. 1-3.