# Principles behind a ball pitching machine

• dilby
In summary: Sketch 3 is the same as Sketch 2, except make the wheel much smaller, say 1 mm diameter.Based on these sketches, what do you think the impact of a smaller wheel would be on the ball's exit speed?In summary, based on the sketches, it appears that a smaller wheel would have a minimal impact on the ball's exit speed.
dilby
Hi all -

I'm not an engineer or even very good at physics, but I was hoping to learn about something I'm interested in. I bought a ball pitching machine that I've outgrown and I'm wondering about either modifying it or even building my own and wanted to know about some of the key principles behind it's physics.

In short, a ball rolls down a tube that is slightly intersected with a large spinning wheel, which has a speed control. The ball brushes this wheel and is projected out. The wheel itself is quite large (30cm), and makes for a relatively immobile machine. I was wondering whether I could reduce the size of this wheel and was wondering how this would affect the performance. (Also other factors i imagine might be the wheel's speed and even perhaps width). So are there principles out there that anyone knows of that I can be pointed in the direction of?

I'm sorry that is probably so poorly explained!

Many thanks!

Welcome to the PF.

Can you post some pictures? I'm more familiar with pitching machines that have two spinning wheels, but it does look like there are some single wheel pitching machines...

dilby said:
and makes for a relatively immobile machine. I was wondering whether I could reduce the size of this wheel and was wondering how this would affect the performance
learn www.google.ru/search?q=angular+speed Another way is to make pneumatic gun.

Z0dCHiY8 said:
Another way is to make pneumatic gun.
That's a good suggestion, but I think it will produce mostly knuckleballs. Can you say why that would probably be true? What does a spinning wheel pitching machine do that a pneumatic gun machine would not?

phinds
berkeman said:
but I think it will produce mostly knuckleballs
wheel can do it too.
berkeman said:
What does a spinning wheel pitching machine do that a pneumatic gun machine would not?
gun is good to control elevation. however, this feature can be realized for wheel too. in many cases, wheel has simplest design == i cannot argue it :)

Z0dCHiY8 said:
wheel can do it too.
Nope. At least not a single-wheel machine. (have you ever played baseball?)

I wonder if the 2-wheel machines use a slightly slower speed on the top wheel to avoid knuckleballs.

berkeman said:
Nope. At least not a single-wheel machine
wheel can be rebuild to catapult, so no spin will be produced.

Z0dCHiY8 said:
wheel can be rebuild to catapult, so no spin will be produced.
That's not how these pitching machines work. You likely have batting cages near you. Time for a road trip!

berkeman said:
That's not how these pitching machines work.
they just kick ball & that kicking can be done in many ways..

1. wheel.
3. slingshot.
4. pneumatic.
5. even acoustic, but it's overkill :)

Z0dCHiY8 said:
they just kick ball & that kicking can be done in many ways..

1. wheel.
3. slingshot.
4. pneumatic.
5. even acoustic, but it's overkill :)
Clearly you do not understand the dynamics of what is being discussed, if you think you can just lump the performance characteristics of a slingshot and a single wheel system. I suggest that for now you quit while you are behind and study the relevant sperical motion and how it specifically affects a baseball before posting any further.

Wrichik Basu and berkeman
@dilby think about what you have to do with a smaller wheel to achieve the same exit speed as with a larger wheel, how long the ball will be in contact with the wheel in each case, and what will be the difference in the dynamics of the ball between the two.

berkeman and jrmichler
Z0dCHiY8 said:
they just kick ball & that kicking can be done in many ways..
No. Like I suggested, you probably have not actually played this sport. That's fine, but please don't mislead the OP into thinking that your advice is good. Thanks.

phinds
dilby said:
In short, a ball rolls down a tube that is slightly intersected with a large spinning wheel, which has a speed control. The ball brushes this wheel and is projected out. The wheel itself is quite large (30cm), and makes for a relatively immobile machine. I was wondering whether I could reduce the size of this wheel and was wondering how this would affect the performance. (Also other factors i imagine might be the wheel's speed and even perhaps width). So are there principles out there that anyone knows of that I can be pointed in the direction of?
If all you want is a general understanding so that you can play "what if", then the ESP method works very well. ESP, in this case, stands for Exaggeration of System Parameters. Make three sketches:

Sketch 1 is a simplified sketch of your machine - a 7 cm diameter ball, a 30 cm wheel, and the backplate that supports the ball.

Sketch 2 is a similar sketch, except make the wheel about 3 cm, or better, 1 cm diameter. Visualize how the ball approaches the wheel, and is pushed through the machine. Notice the similarities and differences from Sketch 1.

Sketch 3 is a similar sketch, except make the wheel about 300 cm diameter. You only need to show a small portion of the wheel. Visualize how the ball approaches the wheel, and is pushed through the machine. Notice the similarities and differences from Sketches 1 and 2. Also study Post #11.

Think about what happens when the ball first touches the wheel, what happens when the wheel makes firm contact with the ball, and the effect of small changes in ball diameter. Think about the performance, the size of the machine, and the relative cost of the machine.

berkeman
Hmm... 1 wheel, 2 wheel, even 3 wheel. Curves, fastballs, sliders, knuckle balls, even left or right handed for some models. It seems to be heavily dependent on attachments and adjustments. It might be a lot of fun to go examine one of these things in operation. I wonder if there's something near me that has such a thing.

https://www.hittingworld.com/Curveball-Pitching-Machines-s/2662.htm

berkeman

## 1. What is the purpose of a ball pitching machine?

The purpose of a ball pitching machine is to simulate the action of a live pitcher in order to improve a player's hitting skills. It can also be used for fielding practice.

## 2. How does a ball pitching machine work?

A ball pitching machine typically uses a motor to power a spinning wheel or arm that propels the ball forward. The speed and trajectory of the ball can be adjusted using controls on the machine.

## 3. What are the benefits of using a ball pitching machine?

Using a ball pitching machine allows players to practice hitting or fielding without the need for a live pitcher. It also allows for consistent and repeatable pitches, which can help players improve their timing and technique.

## 4. Are there different types of ball pitching machines?

Yes, there are different types of ball pitching machines, including arm-style machines, wheel-style machines, and compressed air machines. Each type has its own advantages and may be better suited for different types of practice.

## 5. Can a ball pitching machine be used for all levels of play?

Yes, ball pitching machines can be used for all levels of play, from youth leagues to professional teams. The speed and difficulty of the pitches can be adjusted to accommodate different skill levels.

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