United States Patent 3878827

A table tennis ball serving apparatus having a hopper which feeds tennis balls at any desired rate to a nozzle where the balls are deposited on a pad on the opposite side of which is a rotating wheel which engages the ball and ejects it with spin thereon in the same manner as an opponent returns a shot in table tennis. The rotating wheel is so mounted on the nozzle that all kinds of spin from full overspin to full underspin may be effected on the table tennis balls ejected by the apparatus.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
124/6, 124/51.1
International Classes:
A63B69/40; (IPC1-7): F41B15/00
Field of Search:
273/26D,29A,29R,30,129 124
View Patent Images:
US Patent References:
3399660Ball throwing machine having two rotatable discs with converging and diverging interstices1968-09-03Swartout
3018769Baseball pitching and fielding practice device1962-01-30Parsoneault
2935980Tennis ball server1960-05-10Graves

Primary Examiner:
Pinkham, Richard C.
Assistant Examiner:
Brown T.
Attorney, Agent or Firm:
Militana, Salvatore G.
What I claim as new and desire to secure by Letters Patent of the United States is

1. A table tennis ball serving apparatus comprising a hopper for containing table tennis balls, a nozzle mounted on said hopper, ball feeding means mounted in said hopper in proximity of the inner end of said nozzle for feeding balls to said nozzle, means operating said ball feeding means, a rotatable collar mounted on said nozzle, locking means for said collar, a ball engaging wheel and pad mounted on said collar, said wheel and said pad positioned in coplanar relation with the axis of said nozzle and in opposing relationship, being on each side of said nozzle at an outer end thereof for receiving and engaging balls passing through said nozzle, power means for rotating said wheel and means for adjusting the distance between said pad and said wheel.

2. The structure as recited by claim 1 wherein said operating means for said ball feeding means comprise a rotatable stem extending through a bottom wall of said hopper, a disc secured to said stem below said bottom wall, a motor mounted on said hopper in proximity of said disc, a motor shaft extending from said motor in substantially parallel and spaced relation with said disc, a drive wheel slidably and rotatably mounted on said shaft, said wheel engaging said disc whereby upon rotation of said motor shaft said disc is compelled to rotate and control means for sliding said wheel along said shaft for varying the speed of rotation of said ball feeding means.

3. The structure as recited by claim 2 wherein said control means comprises a hub mounted on said drive wheel and extending about said motor shaft, said hub having a peripheral groove and an elongated member lying in said groove, said elongated member being secured at one end with its other end being free for swinging said hub and said drive wheel radially along said disc.


1. Field of the Invention

This invention relates to ball ejecting devices and is more particularly directed to a table tennis robot which is capable of throwing balls at any desired rate and provide all types of spin to the balls being served.

2. Description of the Prior Art

The conventional table tennis robots or ball serving devices are quite complicated and expensive in cost. They are normally provided with a pair of rotating wheels that engage and eject the balls, each wheel being provided with a motor for rotating same. There is also a third motor that actuates a ball feeding device that delivers a table tennis ball to the rotating wheels. In addition thereto, these motors have to be of variable speed type in order to permit variation in the rate of balls being ejected and the speed at which the balls are ejected as well as the amount and kind of spin applied to the balls.

The present invention contemplates avoiding certain of the above indicated structures that effect the high cost of the devices.


A principal object of the present invention is to provide a table tennis serving apparatus that is simple in construction, extremely effective in its function of serving balls having various spins and being served at any desired rate.

Another object of the present invention is to provide a table tennis ball serving apparatus that utilizes only one wheel for ejecting the balls and a total of only two motors, one to operate the ball ejecting wheel and a second motor for feeding the balls to the wheel without any loss of the functions found necessary in table tennis ball serving devices.

A further object of the present invention is to provide a table tennis ball serving device with a nozzle through which the balls are fed and a rotatably mounted collar thereon to which are attached a wheel and a pad in opposing and spaced relation for receiving the bals and ejecting them with any desired spin thereon.

A still further object of the present invention is to provide a table tennis ball serving device with a hopper in which a variable speed ball feeding device is mounted with a constant speed motor actuating the ball feeding device.

With these and other objects in view, the invention will be best understood from a consideration of the following detailed description taken in connection with the acompanying drawings forming a part of this specification, with the understanding, however, that the invention is not confined to any strict conformity with the showing of the drawings but may be changed or modified so long as such changes or modifications mark no material departure from the salient features of the invention as expressed in the appended claims.


In the drawings:

FIG. 1 is a side elevational view of a table tennis ball ejecting device constructed in accordance with my invention.

FIG. 2 is a side elevational view.

FIG. 3 is a perspective view shown with the hopper cover shown removed.

FIG. 4 is a cross sectional view taken along the line 4--4 of FIG. 1.

FIG. 5 is a cross sectional view taken along the line 5--5 of FIG. 2.

FIG. 6 is a cross sectional view taken along the line 6--6 of FIG. 4.


Referring to the drawings wherein like numerals are used to designate similar parts throughout the several views, the numeral 10 refers to a table tennis robot constructed in accordance with my invention for the purpose of ejecting or serving a table tennis ball with various spins thereon in the same manner as an opponent in table tennis hits and returns the paddled ball. The robot 10 consists of a conventional adjustable clamp 11 for attaching the device 10 to the edge of the table on which the game is played and is provided with a tubular portion 12 for receiving a support member 13 that supports the device 10 in an upright position. The robot 10 may be adjusted to any desired height above the table by a thumb bolt 13 threadedly mounted in the tubular portion 12 to frictionally engaging the support member 14.

The robot 10 itself is pivotally mounted on the support member 14 for varying the vertical angle of ejection of the table tennis balls above or below the horizontal by means of a pivot plate member 15 pivotally mounted by a bolt 16 to the support member 14 at its lower end and secured at its upper end to a feeder tray -T- by bolts 18. The pivot plate is provided with an arcuate slot 19 through which a bolt 17 extends. The bolt 17 is threaded into the support rod 14 and tightened against the pivot plate 15 to secure the robot 10 at the desired angle at which the balls 21 are to be ejected.

The feeder tray -T- consists of a base plate 23 having an upright rim portion 24 forming a shallow container for the table tennis balls 21 with an opening 25 through which the balls 21 pass into and through a tubular throat member or nozzle 26 positioned on the rim 24 at an opening 25. An opening in the center of the base plate 23 receives a stem 27 extending upwardly of a disc 28 mounted below the base plate 23. Secured to the upper portion of the stem 27 is a cylinder 29 having a plurality of vanes 30 extending radially therefrom to form a feeder rotor actuated by a motor 31. The motor 31 mounted on a bracket 32 and extending below the base plate 23 is provided with a shaft 33 that extends in parallel and spaced relation to the disc 28. The shaft 33 has a cross section that is cylindrical with a flat surface on a part thereof extending along the full length of the shaft 33 to compel a drive wheel 34 that is slidably mounted thereon to rotate in unison with the motor shaft 33. Attached to the drive wheel 34 is a hub 35 having a peripheral slotted portion 36 at the center thereof. Extending along and resting on the slotted portion 36 is an actuator rod 37. The rod 37 is supported at one end by a bracket 38 depending from the lower surface of the base plate 23. The rod 37 extends through an enlarged opening 39 in the bracket 38. By swinging the free end of the actuator rod 37, the drive wheel 34 will slide along the motor shaft 33 to engage the disc 28 at different distances from its center of rotation so that the speed of the motor 31 which speed is constant can be varied by the rotational velocity of the disc 28. As shown by FIG. 5, the rotational velocity of the disc 28 is greater at the position of the drive wheel shown by solid lines than the position of the drive wheel 34 shown by dotted lines.

Mounted on the nozzle 26 is a split collar-like clamp 40 that is adjustably secured thereon by a bolt 41. Extending forwardly from one side of the clamp 40 is a motor support plate 42 on which is mounted a motor 43. The motor 43 is provided with a shaft 44 on which is mounted a disc or wheel 45, the wheel 45 being in coplanar relation with the axis of the nozzle 26 and in position so as to engage the upper surface of the table tennis ball 21 as it leaves the nozzle 26. A pad 46 mounted directly below the wheel 45 engages the lower surface of the table tennis ball 21 and is in coplanar relation with the axis of the nozzle 26 and the wheel 45. The pad 46 is mounted on a resilient support member 47 that extends from the lower portion of the collar 40. The position of the pad 46 may be adjusted in the path of the balls 21 by means of a bolt 48 that is threadedly received by a bore 49 in the support member 47 and bears against the outer surface of the nozzle 26. By threading the adjusting bolt 48 in the bore 49, the bolt 48 will bear against the nozzle 21 and cause the support member 47 and pad 46 to swing downwardly away from the wheel 45. Both the pad 46 and the outer rim of the wheel 45 are provided with an abrasive material in order to grip the balls 21 as they leave the nozzle 26 to eject the balls 21 forcefully. An open recepacle 50 of appropriate size to hold a large number of table tennis balls 21 is mounted in place over the feeder tray -T- forming a hopper for the balls 21.

In the normal use of my table tennis ball serving apparatus, the device 10 is secured to the edge of the table tennis table by means of the clamp 11. By use of the wing bolt 13, the device 10 may be adjusted to position the nozzle 26 at any desired height above the table. Then the angle of the nozzle 26 with relation to the horizontal may be adjusted by loosening the bolt 17 and pivoting the device 10 about the pivot bolt 16 and then tightening the bolt 17 to secure the device.

Now, the hopper 50 is filled with table tennis balls and motors 43 and 31 energized. Motor 31 will cause the rotation of the impeller 29, 30 which directs a ball 21 into and through the nozzle 26. The motor 43 causes the wheel 45 to rotate, which wheel engates the ball 21 that has left the nozzle 26 and is positioned between the pad 46 and the rotating wheel 45. The ball 21 so engaged is ejected forwardly of the device 10 with spin on the ball 21 imparted to it by the spinning wheel 45.

With the wheel 45 positioned above the pad 46, the spin imparted to the ball 21 being ejected by the rotating wheel 45 will be overspin. Now if the adjustable bolt 41 is loosened and the collar 40 rotated about the nozzle 26 to reverse the positions of the wheel 45 and the pad 46 so that the wheel 45 is now below the pad, the ejected ball 21 will have underspin imparted thereto. Any angle spin can also be imparted to the ejected balls 21 by rotating the collar 40 to place the wheel 45 at any position between its upper and lower positions. Also, the amount of spin imparted to a ball 21 may be controlled by loosening or tightening the adjusting bolt 48. The tighter the pad 46 engages a ball 21 passing between the pad 46 and rotating wheel 45, the greater the amount of spin is imparted to that ball as it is ejected thereby. If it is desired to vary the rate at which the table tennis balls 21 are being served by my apparatus 10, all that need be done is swing the free end of the control rod 37 to slide the drive wheel 34 along the surface of the disc 28. If one wishes to increase the rate at which the balls 21 are to be served the apparatus 10, the control rod 37 is swung to slide the drive wheel 34 towards the center of the disc 28 and vice versa if it is desired to slow down the rate at which balls 21 are served by the apparatus 10.