US 4,027,646 A · Propulsion device for tennis balls and like spherical objects

Abstract

A propulsion device is provided, designed especially for discharging tennis balls for practice purposes, at selected angles of inclination, and at a predetermined, selected velocity. Employed in the device is a distributor, which is disposed between a hopper and an air pressurizing drum, the distributor being designed to feed balls, one at a time, to the drum, at predetermined intervals. The distributor is disposed between the hopper and drum in such fashion as to cause the spherical objects to be efficiently agitated within the hopper, by passage over the exteriorly cylindrical surface of the drum while moving to the point at which the objects feed into the drum. Efficient agitation of the spherical objects within the hopper thus assures to the maximum extent that the distributor will be fully charged with said objects. A trap door, normally closed by air pressure within the drum, is moved with maximum speed to an open position responsive to the free fall of a spherical object from the distributor into the drum, and moves with equal speed back to a closed position. By holding the open time of the trap door to a minimum, it becomes possible for the device to be interiorly constructed with a simple receiving pipe characterized by an absence of annular induced air flow assemblies and other arrangements which have heretofore been employed.

Claims14

Dependent claims

In a propulsion device for spherical objects, of the type including a discharge barrel, a communicating drum in which air pressure is built up behind each of said objects for propelling the same forcibly from the barrel, and a trap door normally closing an opening into said drum by air pressure within the drum, the improvement comprising:

means mounting the trap door and defining said opening into said drum so that a spherical object fed into the drum through said opening will build up kinetic energy while in free fall vertically downwardly through said mounting means into the drum to an extent effective to momentarily bias the door to a substantially vertical open position while said object is still in free fall said trap door, in so opening, momentarily inhibiting free fall of the spherical object;
and means within the drum to which said object, while regaining substantially free fall, will gravitate clear of the trap door, so as to permit an immediate return of the trap door to a closed position free of any restraint imposed thereon by the spherical object.

In a propulsion device for spherical objects of the type including a discharge barrel, a hopper for holding a quantity of said objects, a pressurized drum disposed below the hopper in communication with the barrel, and a rotating distributor for sequentially feeding said objects into the drum from the hopper, said drum having a curved top wall and said distributor having an annular series of feed sleeves carrying said objects into position to be fed into the drum, the improvement comprising:

a feed opening formed in said top wall of the drum at a location such that said sleeves will be moved in succession into registration therewith for passage of said objects from the sleeves through said opening into the drum;
and means mounting the distributor with the sleeves disposed in a plane approximately tangential to said curved top wall of the drum, said sleeves being bottomless and cooperating with the curved top wall of the drum to permit objects supported therein to move upwardly and downwardly therewithin, and to permit said objects to be individually rotated, during rotation of the distributor with said sleeve-supported objects in contact with the top wall of the drum, thus to agitate the spherical objects within the hopper disposed above the distributor in contact with the objects located within the distributor sleeves.

Dependencies are inferred from the claim text.

Propulsion device for tennis balls and like spherical objects

Life of this patent

Propulsion device for tennis balls and like spherical objects

Life of this patent

Abstract

Claims14