JPH049069B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a batting practice machine for baseball, tennis, etc.

[Background technology]

Conventionally, various batting practice machines have been proposed in which a pitching arm is rotated using a biasing force of a spring or the like to throw out a ball. In this type of batting practice machine, if the ball holding part on the pitching arm is formed so that it contacts the ball over a wide area such as a flat surface, the ball will roll on the pitching arm because the pitching arm is flat, and therefore the ball will not be held. It becomes unstable and the trajectory of the ball becomes unstable.

For this reason, conventionally, for example,
As shown in the above publication, a pitching arm is proposed in which a ball is held between a pair of arms (ball support portion) separated by a certain period of time. However, the ball is held only between a pair of arms (in two places), and although an uneven part is formed on the ball contact surface of the arm to prevent the ball from moving during pitching, the rotational force of the arm is If the ball is not fast, the ball will move and the ball will have an unstable trajectory. Also, in this example, even if the ball moves,
Although the ball hits a control surface provided at the end of the arm, there are still cases in which the ball hits the control surface and other times it does not hit the control surface, resulting in a problem that the trajectory of the ball varies.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a batting practice machine that can securely hold a ball so that it does not move when pitching and can stabilize the trajectory of the ball.

[Disclosure of the invention]

In the batting practice machine of the present invention, in which the pitching arm is rotated by energy stored in an explosive material to throw the ball, the pitching arm is formed integrally with a pair of wire rods with a distance that is large enough to hold the ball. The ball is comprised of a pair of unit arms, the tips of which are tilted in the pitching direction to hold the ball at the bent front and rear positions, and a torsion coil spring part is provided at the base to provide rotational driving force to the unit arms. It was formed.

In this way, the pitching arm pitching arm is formed by a pair of parallel unit arms, and the tips of the arms are tilted in the pitching direction, so the ball does not roll on the pitching arm when pitching, and the ball can be held in a stable state while pitching. be done. Further, since rotational driving force is applied to the pitching arm integrally formed from a pair of wire rods by a torsion coil spring formed at its base, a separate drive source is not required and the number of parts can be reduced. Additionally, the structure is simplified, the weight and size can be reduced, and transportation is easy.

Embodiment An embodiment of the present invention is shown in FIGS. 1 to 16. In the figure, reference numeral 1 denotes a main body case, which has a ball throwing port 2 (FIG. 6) on the front and a ball feeding port 3 (FIG. 2) on the side. Inside the main body case 1, a pair of parallel guide rails 4 (FIGS. 1 and 2) for receiving the ball M sent from the ball feeding port 3 are provided, and a pitching arm 6 is provided.
, a ball set arm 7, and a drive mechanism for these are housed together with a U-shaped frame 8. A groove-shaped first ball stocker 9 (FIG. 6) is connected to the ball feeding port 3, and a second ball stocker 10 is connected to the first ball stocker 9 and the coupling fitting 1.
It is inherited by 1. 12 is a leg, and 13 is a feed port cover.

The driving means for the pitching arm 6 will be explained. The pitching arm 6 is made of a wire spring, and is deflected by the rotation of the cam 14, and when it comes off the cam 14, its tip rotates by the elastic force of the deflection, and throws out the ball M. Specifically, the pitching arm 6 consists of two parallel unit arms 6A and 6B (FIG. 3).
A torsion coil spring portion 15 is integrally extended at the base end of each unit arm 6A, 6B. The tips of each unit arm 6A, 6B are inclined and continuous in the pitching direction, and the ball M is
The ball holding portion 6C can be held at three points: the parallel portion of B and the continuous portion. The inclination angle of the tip and the distance between both unit arms 6A, 6B will be described in detail later. A cam follower shaft 17, on which a cam follower 16 (FIG. 4) is rotatably mounted, is fixed by welding or the like to the middle of the pitching arm 6 in the length direction. The pitching arm 6 has a pipe-shaped arm support shaft 18 (fifth
A torsion coil spring part 15 is rotatably fitted and supported in the figure), and an engaging part 15a provided at the tip of the torsion coil spring part 15 engages with an arm spring holding part 20 of the frame 8. There is. Arm support shaft 1
8 is attached to the frame 8. Cam follower 1
6 is in rolling contact with the cam 14.

The diameter of the cam 14 gradually increases in the rotational direction,
There is a discontinuous small path along the way. The cam 14 is driven together with the ball set arm 7 by a motor. This drive transmission system will be explained. A geared motor 21, in which a motor and a speed reducer are integrated, is fixed to the frame 8 with screws 22 (Fig. 4), and an output shaft 2 of the geared motor 21 has a D-cut shape.
A small gear 23 is press-fitted and fixed to 1a. Further, a large gear 26 having a protrusion 25 for operating the cam 14 and the ball set arm 7 is press-fitted into the camshaft 24 having a spline portion near the center. After this, the camshaft 24 is fitted into the hole of the frame 8,
A camshaft bushing 24' (FIG. 5) serving as a bearing is arranged between the camshaft 24 and the hole in the frame 8. At this time, the camshaft 24 is inserted by expanding the U-shaped frame 8 in the B direction (FIG. 5), and after insertion, the camshaft bushing 24' is inserted in the C direction.
By installing the camshaft 24 in this manner, the large gear 26 meshes with the small gear 23. Note that the arm support shaft 18 is attached to the frame 8 in the same manner as the camshaft 24.

The ball set arm 7 is rotatably attached to the frame 8 by a screw 28 via a ball set arm collar 27, and is always urged downward by a set arm spring 29. The base end of the ball set arm 7 is connected to the protrusion 2 of the large gear 26.
5 to swing in synchronization with the rotation of the cam 14, and the other end includes a ball feeding section 7a for feeding the waiting ball _M1 into the guide rail 4, and a ball feeding section 7a for feeding the waiting ball M2 into the guide rail ₄ . Ball stopper part 7b to hold in position
have. The circumferential position of the protrusion 25 of the large gear 26 is such that the ball setting arm 7 is swung when the cam 14 is not in contact with the cam follower 16 of the pitching arm 6. A damper 31 is further fixed to the frame 8 via a damper stay 30. The damper 31 serves as a stopper for the pitching arm 6, and is made of an elastic body such as rubber.

The storage state of the mechanism incorporated in the frame 8 and the overall configuration of the main body case 1 will be explained. The main body case 1 is divided at the center into a left cover 1A and a right cover 1B, and is provided with a front cover 1C. The front cover 1C has a ball throwing opening 2. Frame 8 is attached to left cover 1A with two screws 32.
Fixed to. The left cover 1A has a dry battery box 33 (FIG. 1) formed in a part thereof, one guide rail 4 is integrally formed therein, and a holding part 48 for thrust fixing of the camshaft bushing 24'. . Next, the right cover 1B is fixed with two screws 34 via the front cover 1C. The other guide rail 4 is also formed on the right cover 1B, and a holding portion for thrust fixing the camshaft bush 24' and the set arm spring 7 is formed. Furthermore, the right cover 1B is provided with the ball feeding port 3, and also includes a stopper part 35 (FIG. 2) for feeding the ball, a stocker holding part 36 for attaching the stocker 9, and a stocker for the ball after the standby ball _M2 . It has a ball feeding port 48 (FIG. 8) through which the ball M above 9 passes. The right cover 1B also has a hole 37 through which one end of the ball set arm 7 swings. In this way, the main body case 1 which has a built-in mechanical part and a stocker mounting function,
Attach the left cover 1A and the right cover 1 with screws 38 (Fig. 1).
It is assembled by tightening B. left cover 1
A handle portion 39 is formed by fitting A and the right cover 1B. In addition, the left and right covers 1
A and 1B are fixed in such a way that they sandwich the power switch 40 and AC adapter terminal 41, respectively.

The guide rail 4 is formed in an arc shape that substantially follows the rotational trajectory of the ball holding portion 6C of the pitching arm 6, and has a shape that gradually moves away from the rotational trajectory of the ball holding portion 6C toward the front in the pitching direction. It is becoming.

A fixed rubber foot 42 is fixed to the lower part of the main body case 1, and an adjusting rubber foot 45 is fixed via an angle adjusting fitting 43 and a pair of angle adjusting screws 44 screwed into the nut portion thereof. Angle adjustment fitting 4
3 is fixed to the main body case 1. The angle adjustment screw 44 is also threaded with a screw fixing nut 46, and by tightening it against the angle adjustment fitting 43, a double nut effect is created and the adjustment rubber foot 45 is securely fixed. By warming the screw fixing nut 46 and turning the angle adjustment screw 44, the setting angle of the main body case 1 in the ground can be changed, and the throwing angle of the ball can be changed arbitrarily. Figure 7 shows the electrical circuit. 47 is a battery.

Operation When the power switch 40 is turned on, the geared motor 21 rotates, and the small gear 23 and large gear 26
The cam 14 rotates via. In the initial state, as shown in FIG. 1, the projection 25 of the large gear 26 is at position a ₁
The ball set arm 7 is rotated clockwise from the state shown in FIG. 1 and begins to push the ball set arm 7. At this time, the cam 14 rotates together with the large gear 26, but the position is set so that the cam surface does not hit the cam follower 16 in the angle range of θ ₁ , so the pitching arm 6 continues to stop at the same position. Only the ball set arm 7 rotates and moves to the position shown in FIG. As a result, the waiting ball M ₁ in the ball waiting area in the main body case 1 is sent over the ball stopper portion 35 formed in the main body case 1 onto the guide rail 4 . At this time, the waiting ball M ₂
is the ball stopper part 7 of the ball set arm 7.
b, the waiting ball _M1 is prevented from flowing into the position where it was, and remains almost stationary at that position.

When the cam 14 rotates by θ ₁ or more, the cam follower 1
6 begins to come into contact with the cam 14, and the pitching arm 6 begins to deflect while storing energy in the D direction via the cam follower 16. Then, from the position shown in Figure 8, cam 1
4 rotates further, the ball set arm 7 returns to its original state due to the spring force of the set arm spring 29. That is, as shown in FIG. 10, the pressing force on the ball set arm 7 is released before the pressing force by the cam 14 reaches its maximum, and therefore the torque for rotating the cam 14 is small. I'll try it. In addition, the ball set arm 7
The waiting ball _M2 , which had been prevented from flowing in by the ball stopper portion 7b, completes its flow into the position of the waiting ball _M1 due to its own weight, and is prepared for the future. On the other hand, as shown in FIG. 10, the ball M sent into the guide rail 4 remains held by the ball holding portion 6C of the pitching arm and the guide rail 4 as the pitching arm 6 rotates in the D direction. Move in direction D.
The cam 14 rotates sequentially, and the pitching arm 6 is in a state where the maximum energy is stored just before the cam surface changes rapidly (the state shown in FIG. 10). At this time, be sure to hold the ball M at three locations on the ball holding portion 6C of the pitching arm 6.
The guide rail 4 is set and formed so that the two are in contact with each other.

FIG. 11 shows the state of the large gear 26 and the pitching arm 6 just before the ball M is thrown. When the cam follower 16 comes off the maximum radius of the cam 14, the energy stored in the torsion coil spring section 15 of the pitching arm 6 causes the pitching arm 6 to move toward the ball M in the E direction.
is kicked out while holding 3 points. The pitching arm 6 moves in the E direction while holding the ball M,
When it comes into contact with the damper 31, the motion stops abruptly, and only the ball M is thrown out with an initial velocity accelerated by the energy of the torsion coil spring section 15.

Here, in FIG. 10, the guide rail 4
The ball M is held by the pitching arm 6 and moves together with the pitching arm 6, so that the user can see the movement of the ball M from the ball outlet 2 on the front cover. Furthermore, as shown in Fig. 11,
The locus Q of the ball holding portion 6C of the pitching arm 6 and the upper surface of the arc-shaped guide rail 4 are arranged to separate from each other as they go diagonally upward from below, that is, in the pitching direction. Therefore, only the pitching arm 6 and the guide rail 4 are used in the initial stage when the ball M is thrown.
Afterwards, it is held only by the tip of the pitching arm 6. Thereafter, the above-described operations are repeated and the balls M stored in the stockers 9 and 10 are successively thrown out. The height of the thrown ball M is determined by the height of the main body case 1 of the adjustable rubber feet 45.
It can be easily changed by changing the amount of protrusion, and can be adjusted to the user's requirements.

Although the operation is as described above, the trajectory of the thrown ball M can be made stable as follows. That is, when the ball M is carried together by the energized pitching arm 6 and the pitching arm 6 collides with the damper 31, and the ball M is thrown out at a constant speed given by the energy,
Two points a and b in the direction of movement of the pitching arm 6 as shown in the figure.
and hold one point c in the direction of centrifugal force action. In the case of a small ball M', hold it at points a', b', and c'. In this way, since the force is brought into contact at only three locations in all directions, the ball M is always held at all three locations, and the trajectory of the ball when thrown out can be made stable. In this case, the settings of points a and b are such that the amount of fall of the ball M is 1.0 mm or more and the angle α ₁
It is desirable that α ₁ <90°. This is because the former is to ensure ball retention, and the latter is because the ball M is stationary when the energy stored in the pitching arm 6 is released and the pitching arm 6 begins to move. unit arm 6A,
To reduce the amount by which the ball M tries to wedge itself between the pitching arms 6 and 6B, and to reduce the loss that reduces the amount of ball flying out when the ball M leaves the pitching arm 6 after the pitching arm 6 collides with the damper 31. It is.

Further, the pitching arm 6 is composed of a pair of parallel unit arms 6A and 6B, and the tip of the pitching arm 6 is inclined in the pitching direction, so that the ball M
Since the ball is held at three locations at the tip of the arm (in other words, at the same position) from immediately after it is delivered until it is thrown, a stable ball path can be obtained and batting practice is easy. In addition, the conventional example
145274), the distance between the tips of the pair of arms (ball bearings) is smaller, so when the supplied ball is supported at the base of the arms (ball bearings) and thrown, it is thrown toward the tips. Move to. Furthermore, in this embodiment, since the pair of unit arms 6A and 6B are integrally formed from wire,
The structure is simple and lightweight.

Next, the shape of the tip of the pitching arm 6 and the rotation of the ball will be described in detail. First, the movement of the ball M at the tip of the pitching arm 6 will be explained. As the pitching arm 6 stores energy, the ball M moves along the guide rail 4 to the bottom. At this time, the ball M is held at three locations on the tip of the pitching arm 6 and two locations on the guide rail 4. As the pitching arm 6 is released, the ball M gradually separates from the guide rail 4 and is held at the tip 3 of the pitching arm 6. It will be retained in place. When the pitching arm 6 is stopped by the damper 31, the ball M is thrown into the air with a certain initial velocity. At this time, simultaneously with the stop of the pitching arm 6, the ball M is thrown out tracing a certain arbitrary trajectory. At that time, when the ball M comes into contact with the tip of the pitching arm 6 and the guide rail 4, a rotational force acts on the ball M, resulting in a corresponding loss, and the flight distance is extremely reduced. For this reason, if the tip of the pitching arm 6 is made completely straight, the ball M will not be in a stable position, and not only will it not be possible to obtain a stable height and distance, but in the worst case, the ball M will fall. Therefore, a certain angle is provided at the tip of the pitching arm 6, and this angle and the opening width of the pitching arm 6 are used to stabilize the ball M.

The method of setting the angle will be explained below.
The opening width of the pitching arm 6 is configured so that when the smallest diameter softball is set, the contact point angle is 90° or less, and the sinking amount H (Figure 15)
The distance is set to 1 mm or more and 3 mm or less. Next, how to set the angle θ (FIG. 16) at the tip of the pitching arm 6. The pitching arm 6 is currently moving at an acceleration α and a velocity v. The ball M receives a force mα in the tangential direction of the trajectory of the pitching arm 6. Further, the ball M tends to spread outward due to the centrifugal force mv/r. The lowest part is the most dangerous for the ball M to fall, and if the ball M is held firmly at this time, the pitching arm 6 will continue to hold the ball M from now on. Therefore, the optimum θ is set based on the balance of forces in the lowest state. Figure 16 shows the force balance relationship. Here, in order to prevent the ball M from falling or shifting, the force Fsin [θ+φ−tan ^-1 (F/mg)] shown in the figure must be
Letting μ be the coefficient of friction between the ball M and the pitching arm 6, the following equation should be satisfied.

F'≦μFsin [θ+φ−tan ⁻¹ (F/mg)] In this example, θ=53°. In addition, It is.

〔Effect of the invention〕

In the batting practice machine of this invention, the pitching arm is formed by a pair of parallel unit arms, and the tips of the arms are tilted in the pitching direction to hold the ball at the bent front and rear positions. The ball is held in the direction of force application. Therefore, the ball does not roll on the pitching arm when pitching, and the ball is pitched with a stable path, resulting in a stable ball path. Furthermore, since the pitching arm is integrally formed from a pair of wire rods and a torsion coil spring section is formed at its base to provide rotational driving force, a separate drive source is not required and the number of parts can be reduced. Additionally, the structure is simplified, the weight and size can be reduced, and transportation is easy.

[Brief explanation of drawings]

FIG. 1 is a side view showing an initial state of an embodiment of the present invention, FIG. 2 is a cutaway front view thereof, FIG. 3 is an enlarged sectional view thereof, and FIG. 4 is a side view of its internal mechanism. Figure 5 is a plan view of the internal mechanism, Figure 6 is a perspective view of the exterior, Figure 7 is the electric circuit diagram, Figure 8 is a side view of the ball supply state, and Figure 9 is the same state. FIG. 10 is a side view of the ball set in its completed state, FIG. 11 is a side view of its pitching state, and FIG. 12 is a perspective view of its pitching arm.
Fig. 13 is an enlarged perspective view of the tip of the pitching arm, Fig. 14 is a side view of the same part, Fig. 15 is a sectional view of the same part, and Fig. 16 also shows the balance of forces at the tip of the pitching arm. FIG. 1... Main body case, 2... Ball throwing opening,
4...Guide rail, 6...Pitching arm, 6C...
...Ball holding part, 7...Ball set arm,
9,10...Ball stock, 14...Cam, 1
5...Torsion coil spring part, 18...Arm support shaft, 21...Geared motor, 25...Protrusion part,
26...Large gear, M...Ball.

Claims (1)

[Scope of Claims] 1. In a batting practice machine equipped with a pitching arm whose base is supported and whose distal end is rotatably driven in forward and reverse directions in a pitching direction and in a direction opposite to the pitching direction within a certain range of angles, the pitching arm throws the ball. The arm is composed of a pair of parallel unit arms integrally formed with a pair of wire rods at a distance that allows the ball to be held, and the tips of the pair of unit arms are tilted in the pitching direction to hold the ball at the bent front and rear positions. , and a torsion coil spring portion is formed at the base to provide rotational driving force to these unit arms. 2. The batting practice machine according to claim 1, wherein the tips of the pair of unit arms are brought close to each other.