Emphatically so. The cone shape is the defining mystery, and I find it very odd.
No. It looks old. I appreciate that that isn’t much to go on.
As to the taper or cone shape, I poked around a bit more, and found that my pulley cone angle is about 7.125 degrees per side, whereas machine tapers for holding themselves together and transmitting torque are generally in the 1 to 2 degree range per side. I’m sure my angle is much too wide to wedge together and stay put.
I agree that angle won’t transmit torque well. But I wonder how much of the narrow angles on current equipment is the result of a century-plus of progress on precision machining? IOW, was that large angle then-current practice as the best they could reliably make?
The curved spokes give me an 1880s-1910s vibe. Although for basic stuff like early mechanized farm implements, I think a lot of the less critical features were manufactured unchanged for decades. So you might well find an 1880s pulley wheel design on some non-critical component of a 1920s production machine.
Maybe an ultra primitive clutch where the wooden (leather faced?) shaft is pushed into the taper until the power couples. It leaves a lot unanswered but might have been handy at the time of water wheels and steam power.
Now that is an interesting idea. Great outside of box thinking.
OTOH …
Commonly with the wide smooth belts they “clutch” the power in and out by removing or adding slack in the loop so the belt either grips or slips freely around the driving wheel.
Also, typically driving wheels are large diameter since the input RPMs coming from a waterwheel or primitive steam engine were real low. The belt & pulley system served to up the RPMs delivered to the driven accessories.
Although if we consider this wheel to be a power take-off, not a power input that could still work with your clutch idea. For reasons of both economy and inertia, the usual belt-drive system was routed to power multiple accessories. Being able to clutch them individually would be a more flexible design.
It would be fine. Static coefficient of friction is (for small angles) the min slope that something would slide down on its own. The slope here is 0.125, which would be a very small coefficient of friction. Dry cast iron on cast iron has a CoF of more like 1.1. Note that the threshold is indifferent to the magnitude of the force, so the high radial forces you’d get by heating the pulley and letting it cool on the axle wouldn’t change the picture.
Again, I certainly don’t know for sure that this is the purpose, but the relatively steep angle compared to other tapers isn’t one of them. It would lock in place just fine.
If you’re referring to my link to an Ebay pulley it has no keyway or threaded bolt to hold it in place so it’s likely a tapered pulley.
In all these scenarios where the pulley is locked on the shaft, what are we thinking? That the pulley does not rotate? Or that the shaft and long heavy radial bar do rotate, and around what axis? It would have to be one or the other. Neither of these seem plausible to me.
the conical clutches I’ve seen usually have the mating surface on a larger diameter. This results in:
Sure looks to me like it’s an idler pulley for a wide leather/canvas belt, and the taper inside the hub is a convenient way to lock it to a shaft, with said shaft support by bearing block(s) that enable rotation.
If you were going to transmit torque across the taper, the walls would be thicker so that you could apply high taper engagement force for good no-slip torque transmission capability.
If it’s an idler it would have to be for a low RPM device. The potato digger shown would be that type of machine. A lot of torque delivered at low speed and this would engage and disengage the mechanism, somewhat similar to a (word that escapes me at the moment, often used to control a windlass… (I hate this word on the tip of my tongue thing)).
ETA: A capstan damnit. Easy to control the transmission of power and release it if power source is being overloaded.
The “shaft” was a short conical stub on a heavy bar a couple feet long, without bearing blocks or other means to enable rotation. The axes of the stub and the bar were ninety degrees apart. It had a through hole near its outer end that would accommodate a cotter pin or similar. There was what appeared to be a heavy nail through the hole, the ends bent and the excess snipped off; this appeared makeshift.
Perhaps something else rotates around/along this thing as it remains stationary, such as an eccentric or lever-arm, like on a modulating control valve, but on a grander scale.
The conical shaft and corresponding taper on the hub might permit a relatively easy changeover of diameters, thereby modifying the overall mechanical action, based on circumstance or need. (Make the 'tater digger cycle faster, dig deeper, fly higher, etc.) Hell I don’t know, just a thought.
I don’t disagree it’s a longshot but it would be perfect for a hand pushed shaft to rotate for, I dunno, a coal hopper pusher or linkage that swings the pump intake. This thing is always turning nearby and I can jam a shaft in and get it and my tool to turn.
Is it possible the 2nd piece not shown is NOT directly related to the pulley?
Not sure how to rule the possibility out entirely. However, when I bought them, the two were assembled with the heavy bent nail pin retaining them together. Their rusty finish matched. The sturdiness of their construction seemed consistent. The large and small ID and axial length of the hub matched the stub. So, this seems pretty implausible to me.
This is a bit of a tangent, but I found it amusing so I’ll share. We might say, why not ask the seller? Well, the seller is an antique shop in farming country, and they have a large and crowded outdoor area with all kinds of interesting (if rusty) items for sale. They had a few enormous hooks, and I bought one. This hook is about four feet tall, and I don’t mean a long rod with the end formed into a little hook, I mean the diameter object it would fit neatly would be about a yard. It’s huge! However, it’s not heavily constructed like some massive crane hook. I can carry it around (though not comfortably). It looks formed out of maybe 2" by 1/2" steel bar, bent the difficult way into a hook shape, with some kind of smithing done to the end to form an eye. Also, unlike most hooks, it was pierced in the middle of the hook portion, and a chain ring captured through this hole, of steel perhaps 3/8" in diameter.
When I bought it, I asked them if they knew what it was for, and they said it was for holding objects that were spinning. You’d place the spinning object in the hook, and it would slow down and come to a stop. Which is a total head-scratcher out of which I can make zero sense.
I spent a while looking around online, and figured out what it was. It’s a cornice hook. It’s used to suspend some kind of scaffolding or platform from the roof of a building, if the building has a cornice (a shallow wall around the edge of the roof). It reaches around the cornice. The small hole with a captured ring is for attaching a safety line you then tie to something further along the roof, so the hook can’t somehow pop off the cornice.
Here’s an example of a new one (though its safety line mount point is at the end rather than the middle of the hook):
In my previous life as a mechanical engineer, I subscribed to an HVAC magazine. There was often a column where the writer talked about The Dead Men, referring to the people who designed old steam heating systems for buildings. The idea being that when you were working on, say, a building built in the early 1900’s and the steam system made no sense to you, you had to realize that The Dead Men knew what they were doing, so don’t screw up their work because you don’t understand it. The writer would then go on to explain why The Dead Men did things the way they did.
So all you need to do is find The Dead Man who designed your pulley and ask him about it. He probably won’t reply. But The Dead Men did write books. Perhaps you could find an engineering handbook from the era when you think the pulley was built to get an understanding of the design. Might be a fine addition to your collection of old parts.
I will do exactly that!
In other news, we went antique shopping again yesterday, and I found ANOTHER coned shaft thingy, with a bit of axle that I’m not throwing out. This one is steeply crowned, not flat faced as the last one. I’m not sure if it’s a pulley or a wheel; the crowning is much steeper than usually found on pulleys, but the edge of the outer diameter is thinner than usually found on wheels. (A wheel needs to handle bumps and edges on things it rides over, so the edge can’t be very thin without risking chips and breaks.) The bit of axle has a square hole. I could imagine the cone system is part of some parking brake. Will post photos later…
I don’t know how much you’ve cleaned the parts but sometimes you can find some markings giving a hint to the manufacturer with close examination.
Looking at some old machinery here I’m wondering if you have an ordinary wheel for moving a large machine around.