I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?

Mcmaster has lots of variations on those. The ones I've used are called
"One-Way Locking Steel Needle-Roller Bearings" available up to 1" shaft.
Standard looking needle roller bearing assembly, acts as a bearing one
way, locks tight the other. Torque capacity might not be high enough for
your use.

Tom Gardner wrote:
I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?

Tom Gardner wrote:

I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?

Perhaps check the one way bearings on http://www.mcmaster.com

The overrunning clutch couplings they have don't seem to quite be it,
but at your low speeds might work.

Pete C.

Tom Gardner wrote:
I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?


Google "sprag" such as these:
http://www.renold.com/Renold/web/sit...utch_Index.asp

On Wed, 22 Feb 2006 22:36:09 GMT, "Tom Gardner"
wrote:

I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?


Google sprag or roller ramp clutch. A quick check shows the
following company has something that might work.

http://www.renold.com/Renold/web/sit...utch_Index.asp

EXACTLY!!! Thanks!


"Wayne Cook" wrote in message
...
On Wed, 22 Feb 2006 22:36:09 GMT, "Tom Gardner"
wrote:

I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move
the
last 6 steps stopped by a limit switch. I don't think I'll need a brake
and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600
plus
the rest of the mechanism for $1000. I think the gearmotor will be
cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?


Google sprag or roller ramp clutch. A quick check shows the
following company has something that might work.

http://www.renold.com/Renold/web/sit...utch_Index.asp

"Tom Gardner" wrote in message
et...
I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move
the
last 6 steps stopped by a limit switch. I don't think I'll need a brake
and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600
plus
the rest of the mechanism for $1000. I think the gearmotor will be
cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?

If you do or can use cycle chain then cycle freewheels would be a cheap
solution.

You can, however, only obtain versions that clutch in one direction...

On Wed, 22 Feb 2006 22:36:09 GMT, "Tom Gardner"
wrote:

I have an application that I need to rotate a shaft at about 3 rpm. The
shaft is 2.5" dia. x 5' long and has a number of cams on it. A ratchet
wheel will move the shaft incrementally through 98 steps and there are 104
teeth on the ratchet. I want to use a gearmotor and chain drive to move the
last 6 steps stopped by a limit switch. I don't think I'll need a brake and
the ratchet wheel has 2 pressure brakes on it to take the jar out of the
ratchet. I also want the gearmotor to "walk" the shaft around for
troubleshooting. All my other machines use an 2.5" air cylinder mechanism
to advance the ratchet the extra teeth. One of these cylinders is $600 plus
the rest of the mechanism for $1000. I think the gearmotor will be cheaper
and better.

My question: I want a one-way clutch so the chain drive will just coast
while the machine ratchets. Is there a one-way clutch that I can mount on
the output shaft of a 1/4 hp gearmotor and just bolt a sprocket to the
clutch?


Horton Air Clutch with a solenoid to disengage power train when you
want it to coast. Ive got about 30 of them.

Tom...perhaps its time to make a road trip to Taft..I think Ive got
Stuff you need. Free to you.

Gunner



"A prudent man foresees the difficulties ahead and prepares for them;
the simpleton goes blindly on and suffers the consequences."
- Proverbs 22:3