Electric ball launcher (go kart wheels)

[Mor]

Hello everyone, this is my first post. Please help if you have any ideas. I’m making a soccer ball launcher. I have two electric motors 1800w,controllers etc. I want to put the motor directly to the wheels,not with a chain,because I want to be able to move the wheels for different sized balls. I don’t need any bearings or anything. The issue I am having is the My motor is a threaded shaft that goes to a lower “double d” part. I’ve found some live axel hubs but they are all 4 bolt but the wheels are all three bolt or keyed. Is there anything that will extend the shaft and can change it to keyed or to three bolt? Or the three stud hubs have a femal spline inside. any ideas on anything else anyone can think of is appreciated. Here are some ideas I have thought about. Thanks

 

[Functional Artist]

Howdy &

IMO trying to set it up, as "direct drive" will overload the motor

I would set up just like a "one wheel peel" go kart

Motor (mounted on a bracket) connected via chain to a sprocket on the wheel (also, mounted on the bracket)
...& this way you can "fine tune" the gear ratio for "launching balls"

Look at minibike rear wheels
...many have a sprocket, built in/onto/connected to the rim

Also, a wider tire like 13 x 6.50 x 6 (again like on a minibike) would probably get a better "grip" on the balls
...& just move the "idler" or shoot to accommodate different size balls

* Did I really just type "to accommodate different size balls"?
...never doin' that again

 

[Mor]

Howdy &

IMO trying to set it up, as "direct drive" will overload the motor

I would set up just like a "one wheel peel" go kart

Motor (mounted on a bracket) connected via chain to a sprocket on the wheel (also, mounted on the bracket)
...& this way you can "fine tune" the gear ratio for "launching balls"

Look at minibike rear wheels
...many have a sprocket, built in/onto/connected to the rim

Also, a wider tire like 13 x 6.50 x 6 (again like on a minibike) would probably get a better "grip" on the balls
...& just move the "idler" or shoot to accommodate different size balls

* Did I really just type "to accommodate different size balls"?
...never doin' that again

Thanks for your reply. I don’t think the motor will get overloaded. It’s not going to running very fast, maybe 1000rpm. The balls only weigh 5 lbs and drills are maybe 10min most before we stop to do something Else. sorry the tires I was referring to in the photo are 7.5in. I’ll post a photo of a brand name launcher. Although it is from a different sport the idea is the same. The good soccer ball launchers are very expensive. (My dad always laughed at the “ball washer” at the golf course. Lol)

 

[redflash]

It might be cheaper and easier to just get a friend, he can kick it to you.....voila !

Da Redflash

 

[Mor]

It might be cheaper and easier to just get a friend, he can kick it to you.....voila !

Da Redflash

I have many people to kick it with. Sometimes when instructing, it is helpful to have a consistent service of the balls.

 

[redflash]

oh sorry I'm not a soccer guy......football uses an oval ball !

 

[madprofessor]

Sally spent a small fortune on her tennis ball server back in the late '60's, still unsure if the lesson fees ever got her squared on the costs, I understand the costs involved. I think you're looking at the locomotion as your answer, while I think the more appropriate view is of the materials used for the launching wheels. Not sure rubber tires, even underinflated, are your best method.
My understanding is that the tighter the psi of the gripping force, the heavier a flywheel you need. Almost any horsepower can in time wind up a heavy flywheel to speed, and then coast along until the next launch. The potential energy of the flywheel's momentum, reduced by the resistance of the gripping force coupled with the accelerative requirements of the launching object would give you the final requirement equation for the speed of the flywheel (motor rpm).
With the amount of unknown factors of weights and forces involved in that, you're going to be like the newest blonde in the typing pool, just a huntin' pecker. Use your wide-thinking imagination to come up with the kinds of materials best suited for gripping and throwing soccer balls, and proceed from there.
I would not recommend a torque converter for that job, since you want precise adjustability. Just a standard centrifugal clutch, since there would be no real load on the acceleration of the motor. Running and stable rpm would be all the adjustability you need.

 

[Mor]

Sally spent a small fortune on her tennis ball server back in the late '60's, still unsure if the lesson fees ever got her squared on the costs, I understand the costs involved. I think you're looking at the locomotion as your answer, while I think the more appropriate view is of the materials used for the launching wheels. Not sure rubber tires, even underinflated, are your best method.
My understanding is that the tighter the psi of the gripping force, the heavier a flywheel you need. Almost any horsepower can in time wind up a heavy flywheel to speed, and then coast along until the next launch. The potential energy of the flywheel's momentum, reduced by the resistance of the gripping force coupled with the accelerative requirements of the launching object would give you the final requirement equation for the speed of the flywheel (motor rpm).
With the amount of unknown factors of weights and forces involved in that, you're going to be like the newest blonde in the typing pool, just a huntin' pecker. Use your wide-thinking imagination to come up with the kinds of materials best suited for gripping and throwing soccer balls, and proceed from there.
I would not recommend a torque converter for that job, since you want precise adjustability. Just a standard centrifugal clutch, since there would be no real load on the acceleration of the motor. Running and stable rpm would be all the adjustability you need.

Thanks for your reply. I have controllers to change, and hold, the speed. Basically I have almost everything you need for a go kart besides frame and wheels. Batteries, motor, controller, accelerator. The smooth rubber tires I linked to should grab the ball sufficiently. changing the distance between the wheels will also help “grab” the ball to throw it. Theoretical calculations with a 13” wheel would be 175mph, obviously the grip etc will change that.The wheel will never be put to that level.That’s why I was looking at smaller wheels (10“or 11”) The ball weighs about 5 lbs. my main issue is not how to build one. My main issue is that I have these motors already. If I had a motor with a keyed shaft, there would be no issue. I’d grab a wheel attach it to the motor, build a frame and basically done. But this motor has a threaded end, then a “double d“shaft. That’s why I am asking you wise experts about my options to be able to use these motors.

Since this isn’t an area of my expertise. I’ll link a different motor that could work. But it is permanent magnet I don’t know if this motor can be used with a controller and accelerator. 12v,2500rpm,2.5hp

I could just buy another two motors for~150$ each(300$)+ controllers,+accelerators..etc.so about 500$. however, since this is for a non profit organization id like to keep the costs down. If you have kids in sports, you understand how organizations Try and keep costs low. (Btw a higher end ball launcher is 5k-10k before shipping and shipping is not cheap for a heavy machine)
sorry if I seem daft, but I’m smart enough to know what I don’t know, and secure enough to ask people that do know. Lol.

 

[madprofessor]

I’m smart enough to know what I don’t know, and secure enough to ask people that do know.

...........and that's all you need to move forward. Since you have some info on higher end OEM launchers, can you find what materials they use for the gripping wheels?..........and how much inflated and/or squeezed pressures are involved? About a heavily weighted flywheel...........
I've seen a softball/baseball launcher (adjustable) that used (sawtooth tread) rubber tires (psi unknown) to shoot the balls, and they had to 3-4 times drive the tent-type ground stakes back into the clay field more snugly if possible. The resistance on contact with the balls would make the launcher rock to the side, which loosened the stakes. That's what you'd avoid with a heavy flywheel. However, thinking about the great torque of electric karts, I wonder how well a setup that launches from a standstill would perform..............nah, forget that.
Here's a link to some standard "double-D" sprockets for electric kart motors, you can pick and choose T8F, 25H, and #35 size sprockets and (exactly) matching axle sprocket and chain between them to suit your purposes. They slip right on, and are held in place by a nut (and spacers and a lockwasher???). Electric Motor Sprocket #35 T8F 25H 11T 9T Tooth For Gokart Scooter Quad Buggy | eBay
Note: Many electric gokarters have used the T8F (fits the motor) #35 sprockets to run standard #35 medium horsepower gokarts. Ask forum members Functional Artist and Epsilon Zero for their opinions on that.

 

[Mor]

...........and that's all you need to move forward. Since you have some info on higher end OEM launchers, can you find what materials they use for the gripping wheels?..........and how much inflated and/or squeezed pressures are involved? About a heavily weighted flywheel...........
I've seen a softball/baseball launcher (adjustable) that used (sawtooth tread) rubber tires (psi unknown) to shoot the balls, and they had to 3-4 times drive the tent-type ground stakes back into the clay field more snugly if possible. The resistance on contact with the balls would make the launcher rock to the side, which loosened the stakes. That's what you'd avoid with a heavy flywheel. However, thinking about the great torque of electric karts, I wonder how well a setup that launches from a standstill would perform..............nah, forget that.
Here's a link to some standard "double-D" sprockets for electric kart motors, you can pick and choose T8F, 25H, and #35 size sprockets and (exactly) matching axle sprocket and chain between them to suit your purposes. They slip right on, and are held in place by a nut (and spacers and a lockwasher???). Electric Motor Sprocket #35 T8F 25H 11T 9T Tooth For Gokart Scooter Quad Buggy | eBay
Note: Many electric gokarters have used the T8F (fits the motor) #35 sprockets to run standard #35 medium horsepower gokarts. Ask forum members Functional Artist and Epsilon Zero for their opinions on that.

Thanks for your reply. The motors are held in place so there is no issue with the launcher rocking. If you see the launcher I linked to, it doesn’t rock/twist at all. the wheels go at a constant speed, then you add the balls in. It doesn’t go from zero to launching for every ball. Remember the ball is only 5lbs. I have sprockets already.As I stated earlier, I don’t want to use a chain and sprocket because I want to move the motors easily. If the motor is directly attached to the wheel all I have to do is unscrew the motor mount and slide it, screw it back on the frame. I’ll give it some more time and thoughts. Currently the ATR shaft I linked to seems like the best option. I can try to get one fabricated with 3 lug pattern to fit a kart rim.

 

[madprofessor]

It doesn’t go from zero to launching for every ball.

Understood, that was just a sudden passing thought about the steady force of electric motors as they ramp up. As said, nah, forget that.
I did previously look at the link of the football launcher, a little bit impressed at the geometric equations necessary to set the 2 grip wheels at their respective angles of attack to develop not only the chosen speed, but also the necessary spiral. Would sure like to know the compound and density of those wheels, a football is about as hard as a soccer ball (or close enough for a launcher).
Do you wish to use a standard motor speed controller to apply various ball speeds out of the launcher in a direct drive fashion? How would you vary the up/down angle?

 

[Mor]

Understood, that was just a sudden passing thought about the steady force of electric motors as they ramp up. As said, nah, forget that.
I did previously look at the link of the football launcher, a little bit impressed at the geometric equations necessary to set the 2 grip wheels at their respective angles of attack to develop not only the chosen speed, but also the necessary spiral. Would sure like to know the compound and density of those wheels, a football is about as hard as a soccer ball (or close enough for a launcher).
Do you wish to use a standard motor speed controller to apply various ball speeds out of the launcher in a direct drive fashion? How would you vary the up/down angle?

Thanks again for your interest. The football launcher is a little different because the wheels tilt individually to help get the spiral. The wheels are 4.80/4.00-8 pneumatic tire. They are white so They don’t mark the balls. Not really an issue for my machine.
the soccer launcher wheels stay aligned. You can change the spin of the ball by having different speeds on each wheel, this is why I want to use two motors. The up and down is as simple as moving the frame up and down. I might add an actuator or not.
I made a drawing, just don’t try and sell it because it’s pretty good. Lol


I will add the cheapest, low level launcher that’s available to help visualize. On Amazon this is 7000$cad and it’s not very good. Website it is 4000$usd before shipping.

 

[Mor]

Minor update for those interested I went to a fabrication shop to get an estimation for two hubs with stems. 2x(Circle 1/4“ steel 4” diameter, 2” shaft with two set screw holes)=around 300$. 2 hrs labour+50$ parts. Basically this but with a 2” rod instead of the longer one in the photo. I did not expect it to be that much lol.

 

[Terry 57]

I'm curious if you looked into hub motors.
I'm going to do a build shortly and I'm was curious if anyone has experience with them.
If you have lmk.
Thanks TH

 

[Mor]

I'm curious if you looked into hub motors.
I'm going to do a build shortly and I'm was curious if anyone has experience with them.
If you have lmk.
Thanks TH

I didn’t really. I was mostly going off machines I have used/viewed during training. The wheels for the smaller hub motors are usually quite narrow. I realize there are cars with hub motors, However I am no expert so maybe there are motors I don’t know about. I want a tire that is 5-7” width.
I am going to get some other quotes about the adapter. For 300$ I can just get two different motors that have the proper shaft to fit any tire I choose.
What are you thinking of building?

 

[Mor]

I'm curious if you looked into hub motors.
I'm going to do a build shortly and I'm was curious if anyone has experience with them.
If you have lmk.
Thanks TH

I’ve been looking into motor hubs. The only issue is that the speed is usually quite a bit lower. The hubs that are 1500-1750rpm are 60-72v which is a massive battery. Hub motors would be the easiest way to build but I don’t think they will work.

 

[Denny]

Thanks again for your interest. The football launcher is a little different because the wheels tilt individually to help get the spiral. The wheels are 4.80/4.00-8 pneumatic tire. They are white so They don’t mark the balls. Not really an issue for my machine.
the soccer launcher wheels stay aligned. You can change the spin of the ball by having different speeds on each wheel, this is why I want to use two motors. The up and down is as simple as moving the frame up and down. I might add an actuator or not.
I made a drawing, just don’t try and sell it because it’s pretty good. Lol

View attachment 135915
I will add the cheapest, low level launcher that’s available to help visualize. On Amazon this is 7000$cad and it’s not very good. Website it is 4000$usd before shipping.


View attachment 135916View attachment 135917

I would never get my balls near that thing!

 

[Mor]

I would never get my balls near that thing!

Nothig wrong with a good tug now and then.

 

[Willie1]

Personally, I wouldn't mount the wheels/tires directly to the motors because the least amount of imbalance would most likely quickly damage the motors. I would mount them on a framework and use chains or belts to drive the wheels/tires mounted on axles. I would try to use rubber isolators on the motor mounts if possible and make the distance between the tires adjustable.
The main body would be similar to this, with transport wheels and a ball loading chute as necessary.

 

[Mor]

Aha!! Thank you for this idea, it’s very smart. I didn’t think of that. I took a screenshot that image. I was Just looking at the jugs machine and how they had their machine set up. Your design would fix the short shaft issue my current motors have. The local hot rod shop said that nothing I could fabricate would make the shaft stable enough, when starting with its original length. I’ve been racking my brain trying to solve the short shaft problem. I’ve almost given up and turned towards using treadmill motors and getting rid of my motors(they are literally still in the box). I really appreciate your input!!!!