Device for recording relative speed of sporting equipment, e.g. skis, ice-skates, snow-boards etc. - comprises slidable scanner on ski contacting snow for successive contact-point time signalling via spaced sensors and lens

摘要

When the ski, snow-board etc. (1) is set in movement, the device fitted to it slidably contacts the surrounding medium and contains a scanner probing an irregularly structured surface of the medium. This produces two or more signals which characterise structural changes of the scanned surface so that the time lag between the two signals can be evaluated to give the speed of the ski. The scanner has a laser anemometer, prism grating, or optical system (19) to optically represent the structure during signal generation. The optical system should lie flush on the medium side to a sliding surface (5) of the ski, using a cylindrical lens system (21) as part of the optical system so the sliding surface (5) forms the subject plane of the system (19). Two sensors (30,31) on the image side of the system (19) are arranged in tandem at pre-set spacing so as to produce the two signals. The sensors consist of photo receivers, photocells, photo-diodes or CCD elements and a re each fronted by a shutter whose slot runs parallel to the longitudinal axis of the lens cylinder (21).