Shooter off of Live Shaft

[geomapguy]

We were looking back to some of this year's designs for shooters and we noticed that some teams drove their wheels through a shaft.

Our team was wondering how exactly you drive a wheel off a shaft via a CIM-ulator with an 8mm keyed output shaft similar to that on a CIM motor.

[Mk.32]

Originally Posted by geomapguy

We were looking back to some of this year's designs for shooters and we noticed that some teams drove their wheels through a shaft.

Our team was wondering how exactly you drive a wheel off a shaft via a CIM-ulator with an 8mm keyed output shaft similar to that on a CIM motor.

We did something similar and used a 8mm to 8mm shaft coupler that we got off McMaster to drive another shaft which the wheel was on.

Later we custom made a gearbox that had an extra long 3/8 keyed shaft that was used with an AM hub.

[geomapguy]

Any pictures from the first version...

Which coupler from McMaster?

[RyanCahoon]

Have you seen the AM 8mm key hub? We didn't do anything more complex than direct drive off the CIM-u-lator shaft. Worked well enough once we got our wheel balanced.

[holygrail]

We used a 1/2 inch coupler from Grainger and lathed the other end of the shaft down to 1/4 inch for an encoder. The set screws work fine, but I wish we had a continuous shaft from the gearbox or a hex axle instead. We used a different motor and gearbox than you though. It was a banebots 775 with a 4:1 gearbox and it has worked pretty well.

[scottandme]

We used a CIM-SIM, but same concept. CIM-SIM > Coupling > 1/2" Keyed Shaft with wheels on 1/2" keyed bore AM hubs.

Just search "shaft couplings" on McMaster and you can drill down to what you need. We used a helical beam coupler that allows for a little bit of angular/axial/parallel misalignment, but a standard coupling would work fine as well.

It's part number 9061K163, 5/16" is close enough to 8mm (0.0025") that it worked fine. They're made by Ruland, who provides the shaft collars in the KoP. Pickier people could use the metric to metric versions and turn down their output shaft for a closer fit, but the clamp style makes it unnecessary in my eyes.

[geomapguy]

So basically we could do

CIM-ulator ----- 8mm AM hub ----- directly to wheel???

[daniel_dsouza]

Our team used a belt, mainly because we needed the reduction from the cimulator. A pleasant side effect was that we could use a larger shaft for the shooting wheel.

[geomapguy]

This year we used:


CIM Motor ----- 8mm hub ----- S35-26LE Sprocket
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S35-26LE Sprocket ----- wheel

this was all inside "our box"

So I was wondering how exactly I could do this outside "our box." So could we use a keyed shaft to control our wheel instead with the same setup?

[Mk.32]

http://24.media.tumblr.com/tumblr_lz...s4zo6_1280.jpg

Edit: image was to massive so I just posted the link

Our shooter from last year, the coupler is McMaster: 2469K2
And we sourced 8mm keyed shaft stock from McMaster as well; the wheel has an 8mm AM hub.

[geomapguy]

So basically:

gearbox (with longer shaft?)----hub----coupler----shaft----wheel

[scottandme]

Originally Posted by geomapguy

So basically we could do

CIM-ulator ----- 8mm AM hub ----- directly to wheel???

Possibly a bit unstable. Better to try a solution like the photo above where the flywheel shaft and wheel are supported on both sides by something other than the gearbox itself. Otherwise that's a pretty big unsupported side load on the gearbox.

Lots of options, all just variations on the same theme. Gearbox shaft > coupler > flywheel shaft. It just depends what you have on hand, your feelings about metric hardware, and whether you have access to a lathe.

cimulator > 8mm to 8mm shaft coupler > 8mm shaft with 8mm AM hubs
cimulator > 5/16" to 1/2" shaft coupler > 1/2" shaft with 1/2" AM hubs

If you want to avoid keys you could also use a hex shaft with the end turned down to match a shaft coupler, and then use the AM hex hubs for the wheel.

[scottandme]

Originally Posted by geomapguy

So basically:

gearbox (with longer shaft?)----hub----coupler----shaft----wheel

More or less, but the wheels attach to the hubs and go on the shafts. The CIM-SIM and Cim-u-lator output shafts are plenty long to fit a coupler, no modifications needed.

[Mk.32]

Originally Posted by geomapguy

So basically:

gearbox (with longer shaft?)----hub----coupler----shaft----wheel

It was
Gearbox [with regular shaft] one end of the coupler goes to this shaft; then longer shaft goes to the other end of the coupler; then the wheel with the hub goes on that shaft. We supported the shaft with a bearing block at the end.

[geomapguy]

Thanks guys

We are trying to prepare for next season by learning as much as we can.

We are going to try to modify our shooter by using CIMulator instead of a CIM motor direct to the hub.