GB327426A - Improvements in or relating to propelling apparatus applicable particularly to the propelling of lawn tennis bails and other game missiles - Google Patents

Abstract

327,426. Dunlop Rubber Co., Ltd., Lacoste, J. R., and Stuart, T. Jan. 1, 1929. Projecting appliances. - In a projecting- appliance for tennis balls &c. of the kind wherein a rotatable spring is flexed by engagement with a stop and on escaping therefrom strikes a ball to project it, the spring is carried by a sleeve rotatable about a fixed spindle. As shown in Figs. 1 and 2, the spring 1 is secured to a sleeve 2 rotatable by means of a handle 5 about a spindle 3 carried by a frame 4. The spring is flexed by the engagement of its free end with a stop comprising a roller 8<a> mounted on a pin 8 that is fixed in adjusted position within a slot 8<b> by means of a handle 8<c>. On escaping from the stop 8, the spring strikes a ball, retained within the end of an arcuate guide 10 by means of adjustable stops 10<d>. Balls 9 are fed by gravity into striking position from a magazine 11 comprising four vertically disposed, cylindrical chambers that carry the balls and are rotatable about a pin 11f into delivering position. The magazine is retained in its four operative positions by a spring-urged plunger 11<g> engaging shallow recesses in the pin 11<f>. To vary the trajectory of the balls, the flange 7<b> carrying the guide 10 and stop 8 is angularly adjustable about the spindle 3 and is fixed in actuated position by a handle 3<b>. The boss of the handle 5 is provided with arcuate slots 5b that receive the attaching screws 5a and allow of adjustment of the handle relatively to the sleeve 2. Backward rotation of the handle is prevented by a pawl 6<c> carried by the sleeve and co-operating with a ratchet wheel 6<a>. The vibrations of the spring 1 are damped by the interposition of compression springs 1<a> between it and a projection 1<b> on the sleeve. In a modification, the sleeve 2 is mounted in ball bearings on the spindle and is connected to the handle 5 through a pawl and ratchet gear. The apparatus is normally arranged in the position shown in Fig. 6 with relation to a wheeled base 12, in which position it is held by the base-members 12d engaging re-entrant slots in the cylindrical lower end of the frame 4. The apparatus is collapsed for storage purposes by removing the spindle 3 from the slot 4<a> in the frame, and securing it within a slot 4<d> at right angles thereto, the frame 4 being then rotated about the wheel axle into the position shown in Fig. 8. The frame 4 is locked in its operative or collapsed positions by bolt 12<b> that pass through the axles of the wheels and engage the members 12d.