Copyright © Françoise Herrmann
To practice varying tennis strokes, without a professional trainer throwing strategically placed balls, Jean René Lacoste invented a ball-throwing device, which was commercially produced by the British Dunlop company. The device was designed to throw balls at selected intervals, speed, and trajectory. The preferred embodiment of the invention was semi-automatic with someone (even a child) cranking the spring-loaded ejection of tennis balls, previously fed into a tubular shoot. The YouTube video included below shows historical footage of Jean René Lacoste, demonstrating both the operation and use of his patented ball-throwing invention.
The ball-throwing device was patented in a family of four patents, in France, the United States, Germany and the UK. The patents were all filed in 1927, and granted the following year, except the US patent, which was granted in 1930.
FR648809 - Lance-balles
US1777976A - Ball-throwing device
GB291044A - An improved ball-throwing device
DE484221C - Vorrichtung zum Werfen von Baellen
The British abstract comprising a short description of the Figure 1 drawing is appended below, together with the patent Figure 1, showing a side view of the Lacoste ball-throwing device.
Projecting-apparatus.-A device for throwing tennis or like balls comprises a blade spring that is coiled round and projects from a continuously rotating shaft, is stressed by engagement with a stop and, upon release, strikes and projects a ball, that is supported at a distance from the top. A blade spring g is rotated in counterclockwise direction by a crank d, is flexed by contact with a stop h and, on slipping past the stop, strikes and projects the lowermost ball of a series of balls contained in a tubular supply shoot l. The stop h and shoot l are carried by a plate i pivoted to a stand a. The speed of delivery of the ball is varied by adjusting the position of the stop h, and the trajectory is varied by rotating the plate i relatively to the stand. [Abstract GB291044A]
Reference
Lacoste
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