The invention relates to a traction or friction measuring apparatus and method of calibration. The apparatus comprising a flat disc traction surface; a spherical ball traction surface constructed and arranged to, in use, contact said disc traction surface; a support structure constructed and arranged to support said disc and ball traction surfaces with respect to one another whilst allowing relative rotational movement therebetween; about an axis, the disc drive means and ball drive operable to effect the relative movement between said disc and ball traction surfaces and include disc speed measuring means and ball speed measuring means, and thereby to generate a traction or friction force therebetween; and force measuring means associated with at least said disc and ball traction surfaces to provide a force measurement arising from said traction or friction force and that measurement of the ball speed and the disc speed can be made at a point of pure rolling between the ball and disc in order to accurately determine the disc track radius based on the known ball track radius. The method comprises the following steps: a. steadily increasing the disc speed and reduce the ball speed (or vice versa) in such a way as to ensure that at some point the speeds pass through a point where the disc and ball are in pure rolling, b. plotting traction force against the slide/roll ratio (SRR), c. observing and recording the values of the motor speeds that correspond to the point of transition from positive to negative (or negative to positive) traction force as the contact passes through pure rolling contact, and, d. determining the disc track radius (DTR) based on the formula: DTR=Ball speed×ball track radius/Disc speed.

The invention relates to a traction or friction measuring apparatus and method of calibration. The apparatus comprising a flat disc traction surface; a spherical ball traction surface constructed and arranged to, in use, contact said disc traction surface; a support structure constructed and arranged to support said disc and ball traction surfaces with respect to one another whilst allowing relative rotational movement therebetween; about an axis, the disc drive means and ball drive operable to effect the relative movement between said disc and ball traction surfaces and include disc speed measuring means and ball speed measuring means, and thereby to generate a traction or friction force therebetween; and force measuring means associated with at least said disc and ball traction surfaces to provide a force measurement arising from said traction or friction force and that measurement of the ball speed and the disc speed can be made at a point of pure rolling between the ball and disc in order to accurately determine the disc track radius based on the known ball track radius. The method comprises the following steps: a. steadily increasing the disc speed and reduce the ball speed (or vice versa) in such a way as to ensure that at some point the speeds pass through a point where the disc and ball are in pure rolling, b. plotting traction force against the slide/roll ratio (SRR), c. observing and recording the values of the motor speeds that correspond to the point of transition from positive to negative (or negative to positive) traction force as the contact passes through pure rolling contact, and, d. determining the disc track radius (DTR) based on the formula: DTR=Ball speed×ball track radius/Disc speed.

Ground surface comprising a substrate (110) having a Young's modulus of between 100 and 1000 GPa, and in which the ground surface has, on a working surface (120), a Vickers hardness of between 1300 and 10 000 kgf/mm.sup.2, and/or a surface coating forming the working surface, in which the surface coating contains amorphous carbon and/or titanium nitride and/or chromium nitride and/or tungsten carbide.

Ground surface comprising a substrate (110) having a Young's modulus of between 100 and 1000 GPa, and in which the ground surface has, on a working surface (120), a Vickers hardness of between 1300 and 10 000 kgf/mm.sup.2, and/or a surface coating forming the working surface, in which the surface coating contains amorphous carbon and/or titanium nitride and/or chromium nitride and/or tungsten carbide.

Apparatus and systems disclosed herein are designed to be used to study various forces acting on an athletic field or an athletic surface caused by the interaction between a shoe and the turf or athletic surface during a simulated impact. Various surfaces can be tested and analyzed, including assessing deceleration, acceleration and cutting traction potential on the surfaces. The disclosed apparatuses and systems allow for the testing of a wide variety of footwear, at any desired impact angle, and at various simulated forces.

Apparatus and systems disclosed herein are designed to be used to study various forces acting on an athletic field or an athletic surface caused by the interaction between a shoe and the turf or athletic surface during a simulated impact. Various surfaces can be tested and analyzed, including assessing deceleration, acceleration and cutting traction potential on the surfaces. The disclosed apparatuses and systems allow for the testing of a wide variety of footwear, at any desired impact angle, and at various simulated forces.

The disclosed invention makes use of slip related values to calculate friction related values and tire stiffness related values and feeds back an estimated tire stiffness relates value or a calculated friction related as a basis for further calculations. In particular, the disclosure relates to methods, apparatuses and computer program products to achieve the mentioned objective.

The disclosed invention makes use of slip related values to calculate friction related values and tire stiffness related values and feeds back an estimated tire stiffness relates value or a calculated friction related as a basis for further calculations. In particular, the disclosure relates to methods, apparatuses and computer program products to achieve the mentioned objective.

A measuring apparatus to measure adhesive performance of a Pressure Sensitive tape or label, which includes an electric or pneumatic actuator that can be triggered manually or remotely to perform a rolling ball tack evaluation at different or extreme conditions to those standardized in an adhesives laboratory, by using a small laboratory oven or small weathering chamber to simulate those extreme conditions. Also, installing this apparatus inside of those chambers and triggering it remotely through the mentioned actuator installed in the apparatus. The triggering systems includes; a power source to convert the standard laboratory high voltage source to low DC voltage to avoid the risk of an electric shock during the apparatus operation, a couple of metallic isolated cables for electric conduction of voltage to the actuator electric coil, an electric control box containing a momentary push button switch, the actuator containing an electric coil, a spring and a metallic mobile piston, and a mechanical fastening system to attach the actuator to the apparatus and the piston to the mechanical ball release system.

A measuring apparatus to measure adhesive performance of a Pressure Sensitive tape or label, which includes an electric or pneumatic actuator that can be triggered manually or remotely to perform a rolling ball tack evaluation at different or extreme conditions to those standardized in an adhesives laboratory, by using a small laboratory oven or small weathering chamber to simulate those extreme conditions. Also, installing this apparatus inside of those chambers and triggering it remotely through the mentioned actuator installed in the apparatus. The triggering systems includes; a power source to convert the standard laboratory high voltage source to low DC voltage to avoid the risk of an electric shock during the apparatus operation, a couple of metallic isolated cables for electric conduction of voltage to the actuator electric coil, an electric control box containing a momentary push button switch, the actuator containing an electric coil, a spring and a metallic mobile piston, and a mechanical fastening system to attach the actuator to the apparatus and the piston to the mechanical ball release system.