Modelling of a carpet installer knee-kicker.
Liu-YS; Huston-RL; Bhattacharya-A
Int J Ind Ergon 1988 May; 2(3):179-182
A method for modeling the mechanical properties of a carpet installer knee kicker was described. The knee kicker was used by the carpet installer to stretch a carpet and consisted of a rod with a viscoelastic knee pad on one end and a plate with barbs to catch and stretch the carpet on the other end. The plate is struck by the installer with the suprapatellar region of the knee. The corresponding model of a spring mass damper system was mathematically described and dynamically tested using a Hewlett Packard Structural Dynamics Analyzer. The stiffness of the knee kicker was dependent upon the compressive load. Typical kick motions were assessed using a four segment multilink system comprising the torso, the thigh, the lower leg, and the foot, and kicking force was evaluated using curve fitting and Laplace transformation techniques. The model was validated by high speed photography of a 148 pound subject using the knee kicker. The authors conclude that the typical knee kicker does not attenuate the impulse transmitted at the knee and suggest that the model can be used in the development of more highly protective knee kicker pads.
NIOSH-Contract; Worker-health; Biomechanics; Mathematical-models; Musculoskeletal-system-disorders; Skeletal-stress; Spinal-cord; Equipment-design; Physical-stress; Mechanics; Tools
International Journal of Industrial Ergonomics