Ideas on how to arrest a rotating bucket

[Industrial Toys]

I wonder if the one stage is shortl enough, if I even need a tensioner?

I bought two (what I thought) were slow speed motors. They were a clear out item and I got them at half price. Maybe that was false economy as I have just increased the complexity and parts count. Four more sprockets, four more bearings, shafts and maybe a little more! I should look to see what motors were available and who knows maybe I couldn't get a slower one anyway. I was going to use a wheel motor that I had. Maybe that would have worked better (slower) with lots of torque but I only had one. I never did try it for RPM.

I just went out and measured the screen that I intend to use. 74 X 48 with what looks like 1" holes. That will determine my bucket size. I have a friend who has made a lot of buckets but the loads are distributed much different on this thing. I figured on beefing up the end plates from normal. Plus there may be falling stones that most buckets don't encounter, short of the curling of the bucket and the stones hit the back, so this steel may have to be heavier as well.

Of bigger concern, is where to put the pivot point. I may have to examine some pictures and try to figure this out as best I can. I wonder how critical that is? After all, the weight is changing all the time depending on the payload at any given moment.

 

[PILOON]

LOL, can't help myself.

To arrest a rotating bucket you just need a LEO with a court order.

 

[BHD]

I am not sure of your plan for the set up for driving the rotation of the bucket, but

my thinking is,
two good sided bearing for the ends of the bucket, 2" or greater,

If you think one needs to drive from both ends, then use a jack shaft across the back of the bucket, 2 bearings about 1" to 1 1/4",

I would think only one motor would be needed,
drive the jack shaft off the motor and use one motor, sprocket on the motor shaft and one on the jack shaft,

I could sketch a picture if that would help, if my description is not enough to grasp, I know I am no word artist,

but I really doubt if you need both ends driven, I would think the bucket would be such that one end driven is enough, If your were trying to hold the bucket from turning with the chains and motor I could see both ends, but your just turning it, some what like a cement mixer,

one may want a motoring valve so the motor does not have un do stress on it when not turning the bucket, (motoring valve lets the hydraulic motor free wheel) or at least a cushion valve (double relief valve between the line so it is not locked solid), solid 1/2 NPT 30 GPM 500-1500 PSI HYD CUSHION VALVE
may have to adjust down so it gives more relief, I would start out with a pressure gauge on the line and see what it takes to rotate the bucket, with load, and then adjust it just a little more than that, that will allow the motor to rotate under some pressure, also remove/relieve some shock loads such as rotating up against the stop.
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If the motor is slower, one could just drive directly one end off the motor, they make restrictors or even variable valves for control of the motor speed, Surplus Center I have used both the variable flow control type as well as the needle valve type, in a reversing situation the needle valve type would most likely work the best, as they will reverse flow (so if one wants to reverse the rotation of the motor).

 

[Industrial Toys]

I already bought 2" bearings for the sides. I got a heavy 2" shaft that I was actually going to run through the bucket for added strength but have given up on that idea for obvious reasons.

These motors were not that big and I thought two would equal out the load. I have thought about your idea of the jackshaft, possibly using my slower more powerfull wheel motor. Then, the side to side forces are still equal and the bucket is not constantly stressed. I had planned pn putting a relief valve to deal with the ineritia issue.

I was just looking through a catalogue. It seems that my motors are about as slow as I am going to get, so at least in that, I don't feel so bad. Too bad there is not some planetary gearbox that bolts on too these, or is there? They are Eaton-Charlyn motors. I don't have unlimted funds but I would glady buy something like that rather then try and make my machine more complicated.

 

[BHD]

many years ago I made a drive for a trencher, yes I geared it down with some chain drive, but I was pushing a 9000 pound tractor and digging with he trencher behind the tractor 4 foot deep and 12 inches wide, in hard soils, the hydraulic motor gave me my creep speed, it ran to small tractor type tires on sides of the trencher, with variable speed that Hydraulic motor would rotate very slowly the tires were about 32 inches tall, and at times we were traveling only about 1/16 of a mile in an hour, and I had a pressure gauge on it and the highest I remember seeing is 600 lb, in soft stuff the tires would spin out at times, (no enough traction) what I am trying to say is I do not think it will take that much to spin the bucket,

I do not think I ever ran the motor at the full rated RPM

it was one of the charlynne type, Geroler motors in the 15 gallon a min range, my remembrance was about a max of 200 rpm,

 

[Industrial Toys]

I spent half the day looking for reducers. Most are clearly made for electric motors and my hydraulic motor has a two bolt mount. I didn't see one reducer with this style of mount. If I ordered the proper ones, they would be over a grand US each! So that is obviously out.

What I did find was wheel motors with a built in brake drum and shoes. I wonder if the four inch bolt circle drum would be sufficient to arrest the bucket. If the bucket edge is level on the ground, I can't imagine much torque trying to turn that bucket. This would kill a few birds with one stone! Just, how to activate the brakes.

 

[BukitCase]

Maybe I'm missing something here - but if you're already using two hydraulic motors to rotate, why not just use a valve with center closed position and let your motors arrest the rotation?

Seems to me that if the motors are strong enough to rotate a full bucket (and slow enough/large enough to work) that they might be able to freeze rotation when the lines are deadheaded.

After all, I don't think you want that (probably unbalanced) load turning 600 rpm anyway ... Steve

 

[Industrial Toys]

This project is really starting to hurt my brain! I think arresting it and indexing it are related but different matters. It should be easily and quickly returned to the same digging position.

I have decided to go with what I have, but simply put one big 12"" diameter sprocket on the bucket end and make the chain case/arms big enough to suit.

Then make a similar ratchet mechanism to what they use.

As for the chain case. I figure on a couple of 3/8" plates far enough apart to house the sprockets and with a hefty torque tube tying them together at the far end. Then weld plate on to the bottm and front, to join them and make the sides enclosed. On top, make some sort of access panel to get at the chain and tensioner.

3/8 plate is arbitrary. I wonder if this will be strong enough given how far out they will have to come to give the rotating bucket clearance. I am not worried about weight. Maybe 1/2" plate would be better.

 

[Industrial Toys]

Last night a friend started to draw this thing on solid works. We closely inspected the various models of these machines and it seems some work different then others to arrest the bucket. They all use a cam, but some rub against the bucket until you reverese it and the mechanism engages and some clearly move the latch in and out. We could not figure this out yet so I am kind of back at square one.

 

[zzvyb6]

Take a look at the "dog clutch" mechanism on a square baler knotter. When tripped, the knotter drive is unlocked and turns. When the knot is complete, the clutch captures the drive mechanism and it is locked in place. In fact, the knotter cam drive is sort of like a miniature drum sieve.