cricket bowling machine / baseball ?

[DrGonzo]

Just posting here for advice on electric DC motors:

I am trying to build my own bowling machine for cricket as the ones on the market are ridiculously expensive.
I can only find some similar instructions for baseball pitching / tennis ball machines.
Any idea if this will work:
http://www.ehow.com/how_2383328_build-pitching-machine.html

There aren't really any diagrams with the instructions so it's difficult to follow...

These are the sorts of wheels I'd probably need: http://www.ifirobotics.com/robot-traction-wheels.shtml
What do I get a DC motor x 2? What ampage, what RPM, etc.

 

[mikhailfaradayski]

Cant really offer much help here, sorry, but i am intrigued anyway.
Would love to see a picture/video of the finished article!

Why have you decided on DC motors? Is this thing to run off batteries?

What about car starter motors? Could be picked for nowt from a scrap yard. Possibly not the ideal thing, but a low cost step in the developement.
Might give you some hefty torque, might fire the balls at you like Viv Richard's big brother on steriods!

best of luck

 

[DrGonzo]

Cant really offer much help here, sorry, but i am intrigued anyway.
Would love to see a picture/video of the finished article!

Why have you decided on DC motors? Is this thing to run off batteries?

What about car starter motors? Could be picked for nowt from a scrap yard. Possibly not the ideal thing, but a low cost step in the developement.
Might give you some hefty torque, might fire the balls at you like Viv Richard's big brother on steriods!

best of luck

It doesn't have to run off batteries but probably easier, I guess it could be plugged in somewhere, definitely want it to be electrical though.
ANy ideas on what sort of RPM I need?
Obviously, when the ball is squeezed between 2 turning rubber wheels, it's going to slow down a bit.

 

[mikhailfaradayski]

RPM required, i can really only guess, but i suppose the velocity of the ball at the point of release would be a good point to start with.
From that you could look at the diameter of the wheels you propose to use and calculate a required peripheral (linear)speed, then work out the required rpm from that.

Again, just a guess, but i would think your budget for this project will have an affect on the design

 

[DrGonzo]

RPM required, i can really only guess, but i suppose the velocity of the ball at the point of release would be a good point to start with.
From that you could look at the diameter of the wheels you propose to use and calculate a required peripheral (linear)speed, then work out the required rpm from that.

Again, just a guess, but i would think your budget for this project will have an affect on the design

Know anywhere to get the motors from?
Ball speeds need to be between 40mph up to about 70.
2 motors so I can vary the speed getting spin or swerve
I'm thinking 2 mounted upright either directly spinning an axle or some kind of geared mechanism probably mounted on plywood would be fine.
Haven't built anything like this in a while

 

[mikhailfaradayski]

What about car starter motors? Could be picked for nowt from a scrap yard. Possibly not the ideal thing, but a low cost step in the developement.
Might give you some hefty torque, might fire the balls at you like Viv Richard's big brother on steriods!

best of luck

 

[DrGonzo]

What about car starter motors? Could be picked for nowt from a scrap yard. Possibly not the ideal thing, but a low cost step in the developement.
Might give you some hefty torque, might fire the balls at you like Viv Richard's big brother on steriods!

best of luck

Hmm
How would I stop it from pulling the pinion gear away?

 

[mikhailfaradayski]

i suppose it would have to be modified somehow. Not being a mechanic, but having seen scrapheap challenge a few times, i know it can be done! :

 

[ban-all-sheds]

Any idea if this will work:
http://www.ehow.com/how_2383328_build-pitching-machine.html[/QUOTE]
Presumably it will work, if you do it right.

But it will work as a baseball pitching machine, not a cricket bowling machine. Apart from a round ball the two are completely different - the balls are different sizes and weights, cricket balls have a raised seam, baseballs do not, but the biggest difference, as well you know, is in the speed range, distance and trajectory, line, length etc of the balls, to say nothing of where, when, how, why and by how much the balls move.

It's probably a lot of work to build this thing; it may well be interesting, and you may end up with a machine which throws balls at you, but it won't be a bowling machine, and anyone who uses it hoping to improve their cricket batting will be sadly disappointed.

 

[DrGonzo]

Any idea if this will work:
http://www.ehow.com/how_2383328_build-pitching-machine.html[/QUOTE]
Presumably it will work, if you do it right.

But it will work as a baseball pitching machine, not a cricket bowling machine. Apart from a round ball the two are completely different - the balls are different sizes and weights, cricket balls have a raised seam, baseballs do not, but the biggest difference, as well you know, is in the speed range, distance and trajectory, line, length etc of the balls, to say nothing of where, when, how, why and by how much the balls move.

It's probably a lot of work to build this thing; it may well be interesting, and you may end up with a machine which throws balls at you, but it won't be a bowling machine, and anyone who uses it hoping to improve their cricket batting will be sadly disappointed.

The machines don;t use real cricket balls, they use dimpled balls, more like hockey balls so the seam shouldn't make too much of a difference.
I get what you are saying though but the trajectory of the ball surely just needs to be aimed up or down to get some bounce?
The real bowling machines are about £2g's including ball feeders so you can see why I might attempt this

 

[ban-all-sheds]

The machines don;t use real cricket balls, they use dimpled balls, more like hockey balls so the seam shouldn't make too much of a difference.

OK, but presumably they mimic the different effects that a bowler will get?

I get what you are saying though but the trajectory of the ball surely just needs to be aimed up or down to get some bounce?

Baseballs are pitched in a flatter plane, from a lower release point than a cricket ball. If you point a pitching machine downwards, how far up the wicket is the ball going to bounce?

The real bowling machines are about £2g's including ball feeders so you can see why I might attempt this

So how are you going to vary the speed?

How are you going to select spin and swing?

That DIY machine doesn't even have any controls related to baseball pitching, so how are you going to make it do anything remotely resembling a cricket delivery?

I'm sure that a real machine is expensive, and I'm sure that you could build a throwing machine for a lot less, but I don't think you could build a bowling machine, and if you don't build one of those you might as well not bother.

 

[DrGonzo]

The machines don;t use real cricket balls, they use dimpled balls, more like hockey balls so the seam shouldn't make too much of a difference.

OK, but presumably they mimic the different effects that a bowler will get?

I get what you are saying though but the trajectory of the ball surely just needs to be aimed up or down to get some bounce?

Baseballs are pitched in a flatter plane, from a lower release point than a cricket ball. If you point a pitching machine downwards, how far up the wicket is the ball going to bounce?

The real bowling machines are about £2g's including ball feeders so you can see why I might attempt this

So how are you going to vary the speed?

How are you going to select spin and swing?

That DIY machine doesn't even have any controls related to baseball pitching, so how are you going to make it do anything remotely resembling a cricket delivery?

I'm sure that a real machine is expensive, and I'm sure that you could build a throwing machine for a lot less, but I don't think you could build a bowling machine, and if you don't build one of those you might as well not bother.

I didn't intend to follow the instructions exactly but try and make a few trial and errors changes. If you look at some of the actual bowling machines they pitch from about 8ft up.
Spin is done by having one wheel rotating fast than the other and tilting the machine.
Swing is done by having it level and wheels spinning different speeds but I imagine this is the hardest to achieve.

As for varying the speed - I have no idea. Presumably a starter motor couldn't be varied?

http://en.wikipedia.org/wiki/Bowling_machine

 

[mikhailfaradayski]

i think subject to suitable design of the controller, most motors can have their speed varied. But speed can also be controlled mechanically.

It seems as though you have a lot of variables yet to be ironed out,
given the cost of a couple of motors (virtually nowt) and a battery or two, a trip to a steel suppliers for some box/angle etc....
It might be a good starting point for a 'mk1' version, just to test out your principles and design.

Its unlikely you will build the finished article in 1 hit. Just look how many goes Dyson has had a making a good vacuum cleaner! Maybe one day he'll get it right and they'll stop blowing up

 

[DrGonzo]

i think subject to suitable design of the controller, most motors can have their speed varied. But speed can also be controlled mechanically.

It seems as though you have a lot of variables yet to be ironed out,
given the cost of a couple of motors (virtually nowt) and a battery or two, a trip to a steel suppliers for some box/angle etc....
It might be a good starting point for a 'mk1' version, just to test out your principles and design.

Its unlikely you will build the finished article in 1 hit. Just look how many goes Dyson has had a making a good vacuum cleaner! Maybe one day he'll get it right and they'll stop blowing up

True Might be "fun" anyway.
Any advice on the motors?

The main mechanism of the machine consists of two heavy wheels, between 30 and 50 cm in diameter, shod with solid or pneumatic rubber tyres, each driven by its own electric motor.

What sort of RPM would I need to get a ball going at up to 70mph?

I think this is going to be the trickiest part:

Most of the space in the machine is a hopper that contains the balls. At the bottom of the hopper, near the front, is a rotor with space for six balls. The balls slot into the spaces on the rotor by gravity, which then takes them into the innards of the mechanism. The rotor passes over a trap-door, which the ball opens with its weight, falling into a small chamber.

A pump is used to provide a flow of air into the chamber that the ball drops into. The airflow pushes the ball along the chamber to rubber ring, or gasket, known as a "restrictor". The restrictor has a hole though it that is sightly smaller than the ball, which the ball presses up against. This seals the hole, so air pressure builds up in the chamber. When the pressure is so great that the restrictor can no longer hold it, the ball bursts though, out of the main body of the machine and into an external tube, which guides it upwards and releases it at the height of a bowler's arm.

 

[ban-all-sheds]

The main mechanism of the machine consists of two heavy wheels, between 30 and 50 cm in diameter, shod with solid or pneumatic rubber tyres, each driven by its own electric motor.

What sort of RPM would I need to get a ball going at up to 70mph?

What's the relationship between the circumference of a circle and its diameter?