Hirth Coupling only for positioning

[Pina87]

Hi
I would like to have angular positioning of a lever with a Hirth couplung. Is it posible to design a couplung with one side of the tooth perpendicular (0° angle) and the other side normal (30°)? How difficult is to maschine such piece.

The problem:
I would like to have the rotation of the lever fixed only in one direction (see attachment). For the axial force I want to use just a simple spring because the lever angular position will be positioned by hand. The maximal torque is estimated to 200Nm.

The problem with a standard Hirth gear is that the tooth's angle is to large which requiers large axial force.

Any other suggestions how to design a mechanism for the same job.
Thnx

 

[MikeHalloran]

The difficulty of machining such a part depends on tiny details like tooth root configuration, tolerances, material, and finish, none of which you have hinted at in your sketch. Go talk to a machinist.

First, eliminate the possibility that you can't use a semi- standard stock machine tool part from a place like Carr-Lane or Reid's.



Mike Halloran
Pembroke Pines, FL, USA

 

[Pina87]

The main function of the gear is to sustain a static loading of 200Nm with minimal axial force (spring). The accuracy is not much that important. The lever just needs to be adjusted to best fit the ergonomy of the operator.
What kind of tolerances (if the outer ring diameter of the gear is 50mm) would you suggest? Where can I find this tolerances?

Thnx

 

[asimpson]

I think a herth coupling is a bit complicated for your requirements to build. Could you this and adapt?

https://sdp-si.com/eStore/Direct.asp?GroupID=980

 

[BrianE22]

End mills can be obtained with various angles: (

http://www.mcmaster.com/#tapered-end-mills/=ijeuiu).

With enough room between teeth you could use a square end mill on one side of the tooth and a tapered end mill on the other side of the tooth. It wouldn't be tough at all to do with a CNC mill. If the teeth are hardened it might be a bit expensive if grinding is required.

 

[unclesyd]

You might want to look at using this type wrench to accomplish the task. I've used the on many different applications. The can be locked with the proper design. I believe that you can get 72 teeth models which will give you some precise positioning
They are all of fthe shelf items

 

[Pina87]

Ok. Let's forget about the Hirth coupling. The positioning can be also done continuously. I'm thinking about a roller clutch whit a release button, to bring it back to start (I can't push it around).
Is anything like that available on the market? How is it called?

 

[Pina87]

One more thing about Hirth joint....what kind of shaft dimension is normally used? What's the main reason for not having it 90° (no shaft)?

 

[MintJulep]

Plenty of off-the-shelf handles that do this.

http://www.carrlane.com/catalog/ind...20609090C0015482013180B041D1E173C3B2853524758