Patent GB-1457197-A (GB)
Title: Tennis practice system
IPC: A63B63/00
Filed: 1974-12-04
Abstract: 1457197 Tennis practice apparatus A I BROWN S P STEIN and E L SWENSEN 4 Dec 1974 [20 Sept 1974 14 Dec 1973] 52458/ 74 Heading At [.Also in Division F2] Tennis practice apparatus comprises an enclosure, Fig. 1 (not shown), towards one end of which is a standard height tennis net structure 4, Fig. 2, an arangement of yieldable screens 11 for collecting balls played over the net, and a device 8 for sucking through pipe 51 the collected balls and for blowing the balls through pipe 30 at predetermined frequency and speed into the enclosure for play. As shown, screen portions 11a, 116 form a dish passing beneath the net 4, so that halls played into the net are also collected. Alternative forms of the screens, Figs. 14, 15 and 23 (not shown), include a ramp in front of the net and extending from ground level up to just above the lower edge of the net, a disc rotatable by a motor and carrying pockets for raising collected balls to the inlet of pipe 51, and ramps inclined downwardly from the sides of the enclosure towards the centre thereof, where the balls are collected. Device 8, Figs. 9 and 10, comprises a casing divided into upper and lower chambers 100, 101- by wall 23. A fan 50 draws in air at 53 to create a suction in chamber 100 and delivers pressurized air at 56 to chamber 101. The suction draws balls 125 through pipe 51, which is connected at 107, the balls then rolling down ramp 56 and into pockets 116 formed in a rotor 26. The rotor is indexed by Geneva-type mechanism 38, 40, 115, Fig. 9, to successively bring ball-containing pockets into registry with an L-shaped stub pipe 1.14 and the pipe 30. During the dwell period of the pocket, a flap valve 63 is opened by mechanism 38, 40, 64, 65 so that air pressure, which has built up in chamber 101, expels the ball. Disc 38, which controls both indexing of pocket's 116 and opening of valve 63, is rotated by a motor (not shown), at a chosen speed corresponding to the desired frequency of ball delivery. A vent valve 128 allows control of the pressure build-up in chamber 101 and thus the speed of ball delivery. A modification of device 8, Figs. 16-19 (not shown), includes a flap, pivotable by disc 38 to control the supply of balls to the pockets 116. Scoring. The area above the net 4 is notionally divided into Vertical zone I, II, III, Fig. 2 and horizontal zones (not shown). For each horizontal zone, light from a source 142 is caused by mirrors to scan the zone in a zigzag path before entering a deteotor 143. A corresponding arrangement (not shown), is provided for each vertical zone. Circuits processing the outputs of the detectors determine which 'area above the net the ball has passed through and scores, preassigned to these areas, are displayed on a scoreboard (140), Figs. 1 and 6 (not shown). The light paths corresponding to zones I, II, III are spaced forwardly of the paths corresponding to the horizontal zones so that the circuits can distinguish between balls passing from device 8 over the net and balls (being played back over the net, only the latter activating the scoreboard. Time of play control. The motors powering the apparatus may be run for fixed periods determined by a coin-freed apparatus.