Over Running Couplers

[To20Chris]

Have to respectfully disagree - if you grease it through the zerk on the perimeter and it comes out around the PTO input shaft, you can be pretty sure you've got it into the mechanism good. I doubt the greasing method is going to be the cause - I'm still betting on sloppy manufacture, such as too much play, too much angle on the steep side of the notches, or poorly formed dogs.

 

[AlanB]

I was in the tractor place yesterday, and grabbed one off the shelf,

You could see the grooves that the dogs go in without even removing the circlip and washer.

Next time you are around one, take a second to look at the angle on the grooves, as viewed from the outside, and I think you will rethink wether it will "lock up" to indefinite amounts of torque.

Al B

 

[Soundguy]

I think you are missing the point a bit about what I said.. i never claimed that the ORC would lock up against indefinate amounts of torque. I'm quite sure you can hit most of these ORC's with enough of a shock load or simple grosly overpower them enough to damage or shear the drive dogs off or damage the spring holding the dogs out.. that's not in question. the question is whether it is designed to give in this manner.. or whether that is a function in excess of its design.

As soon as speeco gets a reply back to me I'm posting it.

I'm guessing it is taking them a while as they are getting an 'approoved' answer cooked up by engineering, then 'smelled' by their legal dept....

Soundguy

 

[Soundguy]

Here's what we've been waiting for. I finally got an email back from SpeeCo.. it's about time! /forums/images/graemlins/cool.gif

I'll post the full test of the message, which includes my message sent to them in quotes at the bottom of thier reply. I asked very specific and very plain questions.. no gotchas or anything like that.. I just asked them to verify ( true or false ) a few statements were were wondering about.

For those who want the answer now: NO the ORC is not designed to slip or give ~any~ in the driven direction.. and if it does.. it is not operating correctly... As I suspected.

Soundguy

Begin quotes....>>>>

Hello,
You are correct on the coupler. In summary, it will stop a large inertia
load from pushing your tractor forward.

Kevin Kuszak
Special Products Company
Customer Service Manager


-----Original Message-----
From: Chris Britton [mailto:c.britton@worldnet.att.net]
Sent: Wednesday, June 09, 2004 12:31 PM
To: Kevin Kuszak
Subject: Question about Speeco Over Running Coupler

Hello,

I have a question about your over running coupler product.

As far as I know, the unit is designed to provide direct drive in one
direction ( from tractor ) and over-run, or ratchet and freewheel in the
other direction, when an implement would be transmitting power back up the
driveline. ( for instance on an older non-live pto tractor using a rotary
cutter ).

Also, as I understand it, the unit is not meant to 'give' or 'slip' any in
the driven direction. And if it does, the unit has been damaged or is not
operating correctly.

Am I correct on these points?

thank you

Chris britton

 

[AlanB]

OK Chris, you are right,,,,

I must have just imagined what mine did, or two brand new ones were defective.

Then again, I did not see how you gleaned all you did out of his answer, but whatever,

You are right. They cannot possibly slip.

 

[HayDR]

Do not confuse the ratchet clutch with the over run clutch. The over-run clutch does free-wheel as you describe. The ratchet clutch in both the single direction and by-directional versions are designed to slip at a prescribed amount of torque. The Speeco Over run clutch is made by Gripwell in India and is designed to handle to 160 nm. They also have a version that is designed to handle up to 240 nm.

 

[Soundguy]

</font><font color="blue" class="small">( must have just imagined what mine did, or two brand new ones were defective )</font>

Based on his affirmative answer of my question, which was: ""Also, as I understand it, the unit is not meant to 'give' or 'slip' any in
the driven direction. And if it does, the unit has been damaged or is not
operating correctly""? Then I would say.. yes.. the unit was defective.. or it was being operated in excess of its capabilities.

</font><font color="blue" class="small">( Then again, I did not see how you gleaned all you did out of his answer, but whatever,
)</font>

I asked 3 very specific questions. He answered affirmative to my 3 specific questions.. that's how I -gleaned- all that info. The fact that his reply was very short means that my questions did not require discussion.. they were true/false answers

</font><font color="blue" class="small">( You are right. They cannot possibly slip )</font>

That's not what was asked, or said. You keep bringing this up as a -red herring-. I ~never~ said that the unit could not possibly slip.. I only said that it was not designed to slip.. and that if it did it was defective, damaged, or being operated in excess of its capabilities. two very different conclusions and answers.


Soundguy

 

[Soundguy]

</font><font color="blue" class="small">( Do not confuse the ratchet clutch with the over run clutch )</font>

Precisely why I refer to the unit in question as an ORC - 0ver running coupler.. not clutch or ratchet.. same as in my question to speeco.

Soundguy

 

[HayDR]

If you want to call it a coupler or a clutch that's ok. In this situation they are the same. The coupler is actually what holds the clutch unit on the shaft. There are even 3 different distinct styles of the over-run clutches available for PTO application.

 

[rich_ncal]

An update

I finally ordered an over running coupler from Agri supply, one of the lower cost units with the roll pin for the PTO shaft, not the quick disconnect type. I received the part this week and installed the unit on Friday and Saturday.

The machining of the splines seem rough (low cost) and the fit is not very snug on the PTO shaft.

The roll pin shipped installed in the unit was too long. This held up the coupler when installed the bush hog was pushing the tractor. I cut down the roll pin to the correct length, and then reinstalled the roll pin and grease zerk fittings. The tractor was still pushed by the bush hog. Then I found one of the grease zerk fittings was longer than the other, too long, extending into the hole for the roll pin. Without this zerk fitting the unit worked and the bush hog did not push the tractor. I had to grind off the end of the zerk fitting. After all of this cutting, grinding and trial in error, finally the unit works properly.

My theory is this unit was sitting on the shelf at a tractor supply store and customers playing with the unit removed the proper grease fitting and roll pin. It also could have been shipped to the store with the incorrect parts.

Thanks for all the responses in to my original post. The responses helped me to understand how this unit should work and helped me to correct the problems with the unit.