JPS637263Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a tennis ball pitching device that shoots a service ball for practicing hitting back in soft-ball tennis.

(Prior art and its problems) Conventionally, this type of pitching device uses air or a spring, rotates an arm, or suddenly tensions a belt to launch the ball. However, there are disadvantages such as no spin is applied to the fired ball, the device has to be large in order to achieve flight distance, the mechanism is complex, and there are many failures due to the large impact.

In addition, as shown in Japanese Patent Application Laid-open No. 52-74439, for example, substantially planar pitching disks are placed facing each other at an appropriate angle with a distance not larger than the diameter of the ball, and the ball is placed within this facing gap. There are some that are fed and rotated, but since the pitching board is essentially a flat surface, if the ball is held near the outer edge, there is a risk that a flexible ball like a tennis ball may slip out of the opposing gap. The ejection speed of the ball is limited by the diameter of the contact point between the pitching board and the ball, and it is necessary to make the pitching board large in order to eject the ball at high speed.

(Object of the Present Invention) An object of the present invention is to eliminate such drawbacks and provide a tennis ball pitching device that is simple in structure, robust, and capable of applying sufficient spin.

(Structure of the present invention) In order to eliminate such drawbacks, the present invention provides two pitching boards that are tilted at symmetrical angles and faced each other, each with a curved portion that curves the outer periphery inward to hold the ball. and a ball chute for supplying the ball from a position in which the slope of the pitching board is larger than the diameter of the ball at the front and smaller than the diameter of the ball at the rear,
The diameter of the contact point between the pitching board and the ball is increased, and the ball is compressed at a position behind the pitching board where the opposing distance is small to provide a spring action.

(effect) This will be explained based on the diagram.

1 is a case, 2 is a ball hopper provided at the top of the case, 3 is a hopper case connected to the hole at the bottom of the ball hopper, 4 and 5 are upper and lower escape plates, which are attached to the escape shaft 6 at an interval somewhat larger than the ball diameter, and are different. Ball holes 7 and 8 are provided at angular positions, for example, at positions 180° different from each other.
is provided. Reference numeral 9 denotes a ball holder provided coaxially with the hopper case 3 between the escape plates 4 and 5, and is connected and supported by the hopper case 3. 1
0 is an operating motor for the escape shaft 6, which is attached to a mounting beam 11 provided inside the case. 12 is a support bearing for the escape shaft 6, and 13 is the escape shaft 6.
A stirring bar attached to the upper end of the ball hopper rotates inside the ball hopper.
4 into the hopper case 3. A front plate 15 is rotatably attached to the case 1 by a hinge 16. 17 is the launch window, 18 is the front plate 15
19 is the base side plate, 20,
Reference numeral 21 designates a pitching board, which has curved parts 22 and 23 whose outer peripheries are curved inward with a diameter approximately equal to the diameter of the ball, and is supported by support stands 26 and 27 via bearings by support shafts 24 and 25, respectively. , the curved parts 22 and 23 are made to face each other and tilted at an appropriate angle, and the front part is opened with a gap larger than the ball diameter, and the rear part is opened with a gap smaller than the ball diameter, and the ball is compressed and held between the curved parts. It's like this.

28 is a pulley provided on one support shaft 24, 29
is the drive motor attached to the base 18, 30 is the pulley attached to the shaft end of the drive motor, and 31 is the V
In this embodiment of the belt, the pulley 30 is a variable pulley, and the tension is adjusted by a moving device 32 of the drive motor 29 to adjust the speed of the support shaft 24. 33 is a flexible shaft that connects the support shafts 24 and 25; the upper end of 34 faces the ball holder 9 via the escape plate 5;
21 is a ball chute that opens toward the lower part of the opposing gap in front of 21; 35 is a guide plate for the ball; 36 is a cover; 37 is an adjusting screw lever supported by case 1;
8 is the handle, 39 is a nut that is screwed into the adjusting screw rod 37 and moves only in the axial direction, and 40 is a lever whose both ends are pivotally connected to the nut 39 and the base side plate 19, and when the nut 39 moves, the base side plate 1
The base 18 and the front plate 15 are rotated about the hinge 16 via the hinge 9.

When the support shaft 24 is rotated by the drive motor 29 via the V-belt 31, the support shaft 25 is rotated via the flexible shaft 33, and the pitching boards 20, 21 are rotated at a constant speed counterclockwise (in the direction of the arrow) at high speed. Rotate. This rotational speed is determined by the V-pulley 30 according to the speed of the pitcher,
For example, it is adjusted to about 2000 to 1400 R/min.

When the ball 14 is put into the ball hopper 2 and the escape shaft 6 is rotated by the operation motor 10,
Balls 14 are thrown into the hopper case 3 by the stirring bar 13.

The balls in the hopper case 3 are dropped one by one from the ball hole 7 into the ball holder 9 by the rotation of the upper escape plate 4, and are dropped from the ball hole 8 of the lower escape plate 5 into the ball chute 34 according to the rotational speed of the escape shaft 6, for example. Dropped every second.

The ball discharged from the lower end of the ball chute 34 is fed by the guide plate 35 from the lower part of the gap in front between the rotating pitching discs 20 and 21, and is sandwiched between the pitching discs 20 and 21. Curved part 2
2, 23 and rotate rapidly to apply centrifugal force. Since the pitching boards 20 and 21 are inclined at appropriate angles, at the position c in FIG. 3 where the gap between the pitching boards is the narrowest, the ball is compressed to, for example, about 2/3 of the diameter of the ball, as shown in FIG. 4 c. , before and after that, for example at position b, the amount of compression of the ball is small, but as shown in Fig. 4b.
The ball 14 is held by the curved parts 22 and 23 as shown in FIG. , 4th from the edge of 23
The ball is released as shown in Figure a, and the repulsive force acting on the inclined surface of the pitching board due to the restoring force of the compressed ball is added to the centrifugal force caused by the rotation, and the ball rapidly flies out in the direction of the tangential line of the pitching board. It is ejected from the ejection window 17 toward the practitioner.

When the ball leaves the pitching board 20, 21,
The lower side of the ball is not in contact with the pitching board, and the upper side of the ball is in contact with the inner surface of the curved part until just before it flies out, giving it linear velocity, so spin is added to the ejected ball. In addition, the injection angle is adjusted by a nut 39 screwed into the adjusting screw rod 37 on the base 18.
At the same time, the entire pitching board is rotated as shown by the dashed line in FIG. 1, and the pitching board is adjusted by changing the direction of inclination of the pitching board.

Note that the adjustment of the rotational speed of the pitching boards 20 and 21 and the adjustment of the angle of the pitching boards are not limited to those in the embodiment.
Use a variable speed motor as the drive motor, or use the base 1
8 can be changed to the case 1 by adjusting the mounting angle and fixing it with screws.

(Effects of the present invention) In this way, the present invention allows the ball to be thrown by making the spacing between the two pitching boards, which are tilted at an appropriate angle and facing each other, larger than the diameter of the ball at the front and sufficiently smaller than the diameter at the rear. Since the outer periphery of the pitching disc is compressed and curved inward, the ball that is supplied between the two pitching discs from the open area in front of the pitching disc is deflected by the curved part at the large diameter part of the outer periphery of the pitching disc. The ball is held securely and is given a large centrifugal force due to its large diameter and high speed rotation, and the ball is compressed at the rear where the facing distance is small, and the repulsive force of the spring action due to the restoring force is added, causing it to fly strongly and rapidly in the tangential direction. At the same time, it is possible to impart spin, and not only is the structure simple and compact, but the attenuation of the ball's momentum is small.
It has the effect of increasing flight distance and improving the practice effect by improving the quality of the ball.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view showing an embodiment of the present invention, Fig. 2 is a cross-sectional view taken along line A-A, and Fig. 3 and Fig. 4 are explanatory diagrams of the pitching board. 1 is a case, 2 is a ball hopper, 3 is a hopper case, 4 and 5 are escape plates, 6 is an escape shaft, 10 is an operating motor, 13 is a stirring bar, 14 is a ball hopper, 15 is a ball hopper, 16 is a ball hopper, 17 is a ball hopper, 18 is a ball hopper, 19 is a ball hopper, 20 is a ball hopper, 21 is a ball hopper, 22 is a ball hopper, 23 is a ball hopper, 24 is a ball hopper, 25 is a ball hopper, 26 is a ball hopper, 27 is a ball hopper, 28
1 is a ball, 15 is a front plate, 16 is a hinge, 17 is a launch window, 18 is a base, 19 is a base side plate, 20,
21 is a pitching board, 22 and 23 are curved parts, 24 and 25
29 is a drive motor; 31 is a V-belt;
32 is a moving device, 33 is a flexible shaft, 34 is a ball shoot, 35 is a guide plate, 37 is an adjustment screw rod, 39 is a
is the nut and 40 is the lever.

Claims (1)

[Scope of utility model registration request] two pitching boards that are symmetrically tilted and facing each other at an appropriate angle; a drive motor that is connected to the pitching board and rotates the pitching board at high speed; and a ball chute that opens at a position and sends the ball into the space between the pitching discs, and the slope of the pitching disc is larger than the diameter of the ball at the front and smaller than the diameter of the ball at the rear opposite to it, compressing the ball. 1. A tennis ball pitching device, characterized in that the outer peripheral edge of each pitching disc is provided with a curved portion curved inwardly with a curved surface having a diameter approximately equal to that of the ball.