Tennis ball throwing machine - has rotating hammer with impact velocity controlled by spring

摘要

A machine for throwing tennis balls for training players has a hopper (6) mounted on a frame (15). The balls roll out of the hopper into the pockets of a rotating wheel driven by the chain (22) from the motor (13). The rotating wheel lifts the balls to a chute (7) which allows them to roll between the guide plates (9). A rotating hammer (10) mounted on a free wheel (11) on the shaft (12) of the motor (13) strikes a ball on each rotation. The impact velocity of the hammer is adjusted by the spring (18) which pushes the crank pin (16) upwards so that the free wheel (11) over-runs the motor shaft (12), at the moment of impact. The compression of the spring (18) is controlled by the bandle (38) through the links (34, 19).