Thread: Bidirectional roller clutch?

I don't know the name of the part that I'm looking for or if they are even roller cluthes. These are used on Safety type milling machine handles and other things. On the mill handles when the power feed is used the the handles just float or slip. If you grab the handle and turn clock wise or counter they grab the screw and turn it. I tried to search for these but don't know what they are called so no luck. Thanks
Andy

Andy, These are sprague or sprag clutches possibly roller or one-way or over-running clutches.Usually found much larger than what you are describing but check with your bearing house.If Torrington is still in buisness they will have a size that corresponds with nearly all their common needle bearing sizes.Our Hyster fan drive in the 1980's had 2 of these with 2 similar bearings for support.We were able to match the items up through the bearing supplier at reduced cost.I believe though they will be one directional rather than bidirectional.And therefore have to be installed with proper orientation,Don't ask me how I know.

Andy, I know what you are talking about, our plant's shop has them on Bridgeport mills that have the 8F power feed installed.

They look exactly like an OEM ball-crank-handle except when you grab it nothing happens (idea is that the handle freewheels instead of windmills when the powerfeed is used). The handle must be kept in a "twist" before there is any positive engagement.

I also have no idea who makes these but would like to know [img]smile.gif[/img]

It is actually Not a roller or sprag clutch, since it is bi-directional.
It is picking up on, or twisting the handle that engages the wheel to the lead scew.
There is a clutch that is engaged via link to the handle.

Sorry, I don't know how to describe it better.
But a search for a two way sprag clutch may be (should be!) fruitless.

I think these might be in the Reid catalog. I definately remember seeing them in some catalog.
Maybe in the mystical McMaster catolog, come to thnk of it.
(How Do you get rid of all those old/extra McMaster catalogs anyway?)

My BP has freewheeling handles, they came fitted from new with the 6F varifeed feeds on X & Y. You might be able to find the parts diagram somewhere on the internet - it shows the "exploded" view of the handles in the powerfeed parts section.

The handle you hold has has a cut out in it. When you twist this handle slightly, the cut out rotates and "cams" a spring loaded plunger so that it engages in the feed unit drive shaft. Very simple, all contained inside the otherwise normal-looking handle assembly. Not perfect though, there is still some backlash which is why they are sometimes disabled...

(edit: I have seen this type locked up, from memory the little plug was removed and a grub screw /set screw put in there so the plunger could be kept engaged).

Another common and not so neat type is to spring load the handle so that it moves axially on its shaft. Commonly locked up and disabled by someone who dislikes this feature, especially if the handles are balanced!

[ 04-10-2007, 06:14 PM: Message edited by: Peter S ]

Thirty-five years ago I worked with Warn automatic locking hubs for the four wheel drive trucks IHC built. They worked in both directions. The wheels would rotate in either direction without driving the axle shaft. But the axle shaft, when rotating, would rotate the wheels. I think they had rollers placed between a round bore and an inner cam. There were springs to keep the rollers centered in the cam grooves, allowing free-wheeling when in two wheel drive. I can't remember now how the cam was made to overcome the centering springs when the axle shaft rotated. We had lots of warranty claims, which is why I took a bunch of them apart.

I did a quick patent search and found a hub like I remember: 1964 Auto locking hub

Here is a later patent for one version of Warn auto locking hub: 1980 Warn patent

Larry

Larry,

MAP (German?) also made a similar self-locking front hub for Land Rovers in the 1960s. As I remember them they usually worked OK - occasionally one would fail to lock fist try, but generally they were fairly trouble free.

franco

Sort of an embarrassing story, but I will share it. I was always used to BP handles that had to be pushedinward to engage. When we took delivery of a new BP in 1993, I could not get the handles to engage... I took one off, and saw the mechanism, and figured how to make it operate... Duh!!!

Thanks for the help on this but I still can't find these. The roller clutch in the 4x4 hubs is about what I was looking for. I tried at the local bearing supply places and on line with no luck.
Andy