Sprockets on a bearing?

[dirtbikerxz]

Is there such a thing as a sprocket on a bearing? The purpose is to have a lever on the same hex shaft of something else, but the lever is controlled by an external force, and not the movement of the hex shaft itself. it just uses the hex shaft as a structure.

[Joe Johnson]

Originally Posted by dirtbikerxz

Is there such a thing as a sprocket on a bearing? The purpose is to have a lever on the same hex shaft of something else, but the lever is controlled by an external force, and not the movement of the hex shaft itself. it just uses the hex shaft as a structure.

Sure, just use a hex bearing from AndyMark or VexPro and put a 1.125" hole in your lever (or sprocket) and Bob's your uncle.

Dr. Joe J.

[dirtbikerxz]

Originally Posted by Joe Johnson

Sure, just use a hex bearing from AndyMark or VexPro and put a 1.125" hole in your lever (or sprocket) and Bob's your uncle.

Dr. Joe J.

Will try that, and second question. What is the best way to directly attach a sprocket to the lever. The normal way is running a hex shaft through the sprocket into the lever, but obviously that's not a option in this case.

[Owen Busler]

We have something very similar on our robot, but we used gears.

http://www.vexrobotics.com/vexpro/mo...sprockets.html

Take a look at those plate sprockets. With those you will be able to put a bearing in the middle, and use the 1.875 inch bolt circle to attach to your rotating lever. This will allow the shaft to spin independent of the plate the sprocket is bolted to.

[dirtbikerxz]

Originally Posted by Owen Busler

We have something very similar on our robot, but we used gears.

http://www.vexrobotics.com/vexpro/mo...sprockets.html

Take a look at those plate sprockets. With those you will be able to put a bearing in the middle, and use the 1.875 inch bolt circle to attach to your rotating lever. This will allow the shaft to spin independent of the plate the sprocket is bolted to.

We have some of these on order, but they won't be in until monday. A local team is hosting a practice competition day this saturday, and we need to gerry rig something before then, just to get a feel for it. Right now I'm thinking drill into a sprocket, make it wide enough for a bearing , and then put spacers between the lever and the sprocket (to make room for the chain), and drill holes into the side of the sprocket and lever, and just run long bolts through them.

Some one PLEASE tell me if there is a better idea that i can do with just normal sprockets, hex bearings, screws, and a drill bit

[Joe Johnson]

If there is a "standard" bolt pattern in first it is the 6 screw pattern on the wheels, sprockets, hubs and such, specifically, 6 clearance holes for #10 screw (.196" or .200" depending on how much slop you are feeling that day) on a 1.875" bolt circle.

The hex hubs from AndyMark and VexPro both use that pattern. VexPro has additional torque transfer norkers (that's a technical term ;-) that fit into mating holes in there sprockets and wheels. They are really nice for some applications. They are overkill in others.

I typically don't use the VexPro norkers but sometimes I do. If I need more torque than I feel comfortable putting on the 6 bolts themselves, then I usually use a larger sprocket and put hole out farther on the sprocket to transfer the torque to the lever.

YMMV.

Dr. Joe J.

[Knufire]

Originally Posted by Joe Johnson

If there is a "standard" bolt pattern in first it is the 6 screw pattern on the wheels, sprockets, hubs and such, specifically, 6 clearance holes for #10 screw (.196" or .200" depending on how much slop you are feeling that day) on a 1.875" bolt circle.

The hex hubs from AndyMark and VexPro both use that pattern. VexPro has additional torque transfer norkers (that's a technical term ;-) that fit into mating holes in there sprockets and wheels. They are really nice for some applications. They are overkill in others.

I typically don't use the VexPro norkers but sometimes I do. If I need more torque than I feel comfortable putting on the 6 bolts themselves, then I usually use a larger sprocket and put hole out farther on the sprocket to transfer the torque to the lever.

YMMV.

Dr. Joe J.

VEX's standard is actually 6 #8s on the same size bolt circle. A lot of teams who have already standardized on #10 bolts just drill them out.

[Bob Steele]

Originally Posted by dirtbikerxz

Is there such a thing as a sprocket on a bearing? The purpose is to have a lever on the same hex shaft of something else, but the lever is controlled by an external force, and not the movement of the hex shaft itself. it just uses the hex shaft as a structure.

FYI This type of application is called a "dead axle" You can certainly use the same axle to run a number of different spockets this way, each with their own power by chain or belt. It is used successfully by many teams.
Good luck!!

[MrForbes]

do you mean an idler sprocket?

McMaster Carr has these....