Mechanical guns and projectors – Fluid pressure – With control for discharge of fluid pressure
Patent
1986-05-16
1988-10-04
Hafer, Robert A.
Mechanical guns and projectors
Fluid pressure
With control for discharge of fluid pressure
273 26D, F41B 1100, A63B 6940
Patent
active
047749288
DESCRIPTION:
BRIEF SUMMARY
The invention relates to apparatuses for sports training, and more specifically to tennis ball projectors.
BACKGROUND ART
Known in the art is a tennis ball projector (cf. USSR Inventor's Certificate No. 577,044, Int. Cl. A 63 B,69/40, "Discoveries, Inventions, Industrial Designs and Trademarks" bulletin No. 39, 1977), comprising a chamber communicating with a source of compressed air.
There is also a ball projection barrel with an outlet end face thereof protruding from the chamber and an inlet end face thereof located in the chamber to admit compressed air therefrom.
The barrel has a side hole wherethrough the barrel communicates with a gate and a branch pipe to admit balls into the gate.
Provision is also made of a valve for periodic communication between the barrel and the chamber, installed close to the chamber-enclosed barrel end face.
The valve is made in the form of a rod-mounted disk interacting with the barrel end face. A spring presses the disk to the barrel inletend face. The valve rod is arranged along the barrel axis in a bushing secured in the chamber cover.
The valve is actuated by an electromagnet with a movable core kinematically associated with the free end of the valve rod by means of a lever. As the core is pulled in or out, the valve is opened or closed respectively. With the valve open, the compressed air is free to enter the barrel and project the ball.
This prior art tennis ball projector may be used effectively for projecting balls at a relatively low speed due to the small effort of the electromagnet to open the valve intended for admission of compressed air into the barrel.
However, to project a ball at a high initial velocity, e.g. to imitate a champion's shot, the effort exerted by the electromagnet must be as great as 400-500N. Such an effort could be attained by increasing considerably the mass of the movable parts of the tennis ball projector and for the electromagnet, which would appreciably augment the weight of the projector and extend essentially the valve opening time.
Slow opening of the valve results in a low efficiency of the tennis ball projector, because the valve opening time is longer than that required for the ball to pass through the barrel. Therefore, a relatively weak flow of compressed air, not a powerful jet of it, enters the barrel, due to which a considerable amount of air is ejected from the barrel after the ball has been shot out. In other words, this amount is not spent for the purpose it is intended for, i.e. for projecting the ball.
DISCLOSURE OF THE INVENTION
The principal object of the present invention is to provide a tennis ball projector, wherein the design of the valve drive would allow the ball projection speed and the projector efficiency to be increased and total weight of the projector decreased.
The foregoing object is attained in a tennis ball projector, comprising a chamber communicating with a source of compressed air, a barrel to project the balls, communicating with the chamber by means of a valve located in the chamber close to the barrel end face and provided with a drive, and also a branch pipe with a gate to admit the balls into the barrel, according to the invention, in which the valve drive is made in the form of a pneumatic chamber permanently communicating with the source of compressed air and also communicating with the atmosphere through an additional valve provided with a remote control arrangement.
The valve drive of the present invention, made in the form of a pneumatic chamber communicating with a source of compressed air and also communicating with the atmosphere through an additional valve allows the valve opening time to be reduced to a minimum.
This has been made possible due to the fact that the mass of said valve drive is very small, and the valve opening time is shorter than that required for the ball to pass through the barrel, because such a design ensures a very quick opening of the valve to admit compressed air into the barrel. As a result, all its energy accumulated in the chamber is spent on imparting
REFERENCES:
patent: 1379403 (1921-05-01), Green
patent: 3400703 (1968-09-01), Rhodes
patent: 3974849 (1976-08-01), Dawson
patent: 4108432 (1978-08-01), Clark et al.
patent: 4212284 (1980-07-01), Speer
Brown Michael
Hafer Robert A.
Sumsky Filial Karkovsky Politekhnichesky Institut Imeni V.J. Len
LandOfFree
Tennis ball projector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Tennis ball projector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tennis ball projector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2150767