4mm The Harboro Stone Co.

[Dave]

Tippler drum - why not use Delrin chain and sprockets?
The cranked link style of chain is exactly the same as that used on heavy excavator crawler tracks and rotary drying kilns / aggregate washing barrels where gear rings are not used, and is pretty much the ideal size for something like a 4mm wagon tippler mechanism.
The large chain wheel could easily be made in a set of segments with the complete ring having every second or third tooth as was typical in practice.
Just need to be careful of having slack to avoid jerky movement but that could easily be achieved by use of a well-sprung idler wheel.

That is something that crossed my mind but I discounted it because I'm not confident that I could space the teeth correctly. I don't even know what the distance (pitch?) between the teeth would need to be. Being more of a bodger than an engineer I can see me spending a lot of time making it and then it not working.

 

[Dave]

I have made a mechanism to hold and release the hopper doors. It's a simple pivoted arm with a pin that pushes against a corresponding ramp between the rails. It works on the bench but has yet to be tested with a load or being pushed against the ramp by a locomotive.

 

[Osgood]

That is something that crossed my mind but I discounted it because I'm not confident that I could space the teeth correctly. I don't even know what the distance (pitch?) between the teeth would need to be. Being more of a bodger than an engineer I can see me spending a lot of time making it and then it not working.

OK, how about this:

You need to get a length of Delrin chain and join it in a loop whose internal diameter is just larger than the outer diameter of the rotary tippler frame where you intend to place the drive.
Pack the chain loop out to be a snug fit such that it can be glued up solid.
Drive with a Delrin sprocket engaging on the chain gear that you have just made.
It will look the job if nothing else.

I've used the 'chain gear rack' bodge a time or two on plant

 

[Dave]

OK, how about this:

You need to get a length of Delrin chain and join it in a loop whose internal diameter is just larger than the outer diameter of the rotary tippler frame where you intend to place the drive.
Pack the chain loop out to be a snug fit such that it can be glued up solid.
Drive with a Delrin sprocket engaging on the chain gear that you have just made.
It will look the job if nothing else.

I've used the 'chain gear rack' bodge a time or two on plant

An excellent idea.

 

[Osgood]

Might pay to engineer some fresh air behind the centre of the chain - I think the Delrin sprocket teeth poke through a bit and it would be better to keep teeth full height, rather than trim them off, for a smooth drive.

 

[simond]

Or my earlier suggestion of toothed belt. Won’t look as good, but the tooth profile is likely shallower.

 

[Ian@StEnochs]

This might be better. The rack is flexible enough to wrap round the wheel though you may need more than one section.

Plastic Rack & Pinion Set - 50mm Rack, 10 Tooth 10mm Pinion

Upgrade your DIY projects with our Plastic Rack & Pinion Set. Includes rack (50mm) and pinion (10mm dia). Get yours now!

ema-models.co.uk

 

[simond]

Wrapping the rack onto something curved is going to change the tooth pitch, though whether it would make a material difference is open to conjecture. I guess the ends of the rack might tend to stick up, 50p piece style too…

 

[Osgood]

If the thoroughly cheapskate (well just look at their motley collection of locos...) Harboro Stone Co was going to make up a rotary wagon tippler in the quarry workshops and could not afford a new gear wheel and pinion set (just imagine the cost....), how would they do it?

Using an old gear ring set off a drying kiln or similar is fraught with problems: I spent an age trying to work out why a 10ft dia ring was running erratically - eventually discovered the pitch of the pinion teeth varied between 4 1/2" and 5 1/4" due to 60+ years of building up of worn teeth by welding and hand dressing, and the main gear varied by almost 1/2" in places!

I reckon they'd either take the track drive chains off an old 54RB face shovel or, if they were feeling flush, splash out on a length of new-fangled Berco crawler undercarriage track chain - think Cat D9 / D10 dozer size - which has holes all ready to bolt chain to tippler, and use in the manner suggested.

 

[Dave]

Thanks for the replies. It's all stuff worth noting for future reference but because of the amount of work involved in constructing a rotary tippler, it is going to be a last resort.

The hopper door release worked quite well but what I didn't account for was the load not wanting to drop out of the hopper. Because the loads are supposed to be shovelled in straight off the quarry floor after blasting I wanted some reasonably large lumps but these simply locked together when the door fell open, because the aperture in the hopper bottom isn't large enough, and needed manual intervention. The size of the aperture is of course limited by the back-to-backs of the wheelsets and the length of the hopper bottom, so the only thing I could do was to have fewer large lumps in the mix. It got to the point that for the load to drop reliably I had far more small rocks than seemed realistic, so the hopper idea has gone.

I'm now on with American-style dump cars. The Oxfordshire Ironstone Company and Lloyds Ironstone Company used this type of wagon on standard gauge in the UK, as did Mountsorrel granite quarries, so I see no reason why Harboro Stone Co. couldn't use them for limestone.


The door lifts as the body tips and so there is a far larger gap for the large rocks to pass through on the model, so I'm hoping these work.

I started off with some second hand Bachmann On30 wagons. Although they are O scale narrow gauge, the bar frames look the part and are no wider over the axleboxes than an ordinary British wagon. The length and wheelbase are about right too. The bodies, on the other hand, are huge!


That problem was soon solved. I had to also make new support/pivots in order to bring the body down to nearer the correct height for 4mm. The Lloyds prototypes were 7ft. 6in. tall and mine now scales at about 8ft.



I still have to put in the intermediate pivot/supports and also need to make the balancing arms for the door opening mechanism. Once those basics are done, and the wagon tested to ensure it can actually dump its load, I will add exterior detail such as reinforcing angle iron and rivets.

 

[Dave]

The operating links are somewhat over-scale but they need to be robust if it is to work reliably. I will file down the screw heads until the slot is gone and once it's all detailed, painted and weathered I think it won't look too bad.

It works.

 

[Giles]

Excellent Dave - much freer motion than the Bachmann bodies! You may find the angle of tip a little low for full discharge, but experimenting will see....

 

[Dave]

Excellent Dave - much freer motion than the Bachmann bodies! You may find the angle of tip a little low for full discharge, but experimenting will see....

Thanks, Giles. You were correct about the angle. The entire load would not discharge as it was, so I made a modification to the crossmembers that the pivot screw goes through. It will now tip until the corners of the body touch the bar frames, which allows the entire load to discharge but now the body remains in the tipped position. I've taken the body off and filed the mounts in case they were binding and have put oil on the pivots but it still won't revert to the upright position. It is very difficult to determine if anything is sticking slightly, or if the few extra degrees of tip have literally swung the balance.

 

[Giles]

Dave, having had many tippers stick down, may I suggest that you wash off the oil, and once dry, brush talcum powder in and around all surfaces and joints. This removes any stickiness from the paint surfaces, which I find contributes enormously to such problems, and also eases joints. You can brush off all excess, so there will be nothing left to see. I do this routinely to all mine, and it makes the difference between working and non-working.
Failing that, a rigid counterweight-weight or pendulum weight mounted under the body under the pivot point might teach it manners
Best

Giles

 

[Dave]

Thanks, Giles. Adding more weight is something I want to avoid. I filled the dump car with the coarse Peco limestone that I have been using and weighed it. Not having any more dump cars just yet I weighted a couple of mineral wagons to the same and ran a test train to see if a rake of three loaded wagons can be taken up the steep gradients but the small engines. They can't, so I'm on the lookout for lighter alternatives to real crushed limestone. Cat litter has been suggested.

I was going to use a trip ramp to tip the car for discharge in the same way that Giles used one on The End Of The Line but getting the edge of the wagon to interface with the body of the car is very difficult due to the door arm uprights. Not only that but the discharge takes place over distance and I have already set up the length of the receiving hopper, which is not much longer than an ordinary 4-wheel wagon.

I am working on a system where a rod comes vertically through the baseboard and pushes at the underside edge of the body in order to tip it. The axleboxes on the car each have a 1mm dia, x 1mm deep magnet glued to them on the non-viewed side. At the discharge hopper a couple of very short lengths of iron bar are glued to correspond with the magnets on the car and are placed so close as to actually make contact with the magnets. The magnets and iron hold the car in place with enough pull to prevent it from tipping or derailing when the rod pushes the tip body over but the pull is very weak against a shear force, so the locomotive has no problem pushing the train off the discharge point.

What I need now are some coil springs to ensure the rod returns with more than just gravity to rely on and some piano wire to make the operating rod to the front of the baseboard. Playing around with this rod gave me an idea that can also allow the hopper wagons to be used. I made a hole through the baseboard and receiving hopper for another rod to rise and fall between the rails. Although the stone jams in the hopper after the ramp opens the hopper doors and will not fall out of its own accord, prodding it from beneath with a wire loosens the rocks and they can fall from the hopper.

I do feel that I'm getting bogged down by all of this wanting to tip or discharge loads and am thinking about abandoning it and instead having the tunnel line carrying just large rocks that would go out on BR Plate wagons, as in the photo link below, and building a (non-working) conveyor belt that feeds the crushing plant.

MikeMorant with Keywords: black hawthorn

See the entire gallery

mikemorant.smugmug.com

 

[NHY 581]

Hi Dave,

Does this help ?

BSC Shepcote Lane Tippler Sidings model railway

BARRIE JONES takes us to the Sheffield area where his compact ‘OO’ finescale layout plays host to part of a steelworks in the late 1980s.

www.keymodelworld.com

Baz is on Rmweb and I'm sure there's a thread on Shepcote Lane.

Rob

 

[Dave]

Hi Dave,

Does this help ?

BSC Shepcote Lane Tippler Sidings model railway

BARRIE JONES takes us to the Sheffield area where his compact ‘OO’ finescale layout plays host to part of a steelworks in the late 1980s.

www.keymodelworld.com

Baz is on Rmweb and I'm sure there's a thread on Shepcote Lane.

Rob

Afraid not, Rob. I've built that sort of tippler before but as I said previously, they take up a lot of space and each wagon has to be uncoupled and recoupled, which would be difficult given where the tippler will be situated.

I have got the rod coming up through the baseboard but now cannot work out exactly how to operate it. Because it has to be sited very close to the dump car's underframe it needs to fall to ground level so the cars can pass it. This means a throw of 30.5mm is required to raise the rod to fully tip the body. The vertical movement of the rod needs to be converted into a horizontal movement that can come out at the front of the baseboard to operate the rod. Some sort of crank arrangement would do it but I simply cannot work out how to make it or determine the dimensions and angles of the crank.

 

[simond]

Dave, draw a horizontal line to represent the rail head, and another below for the baseboard too, and another one below that for the underside of your baseboard.

draw a vertical line to represent the axis of your pusher, and mark off where it needs to be, T top and B bottom.

Mark mid-way between these marks, that’s H half travel. This is above the baseboard.

Measure from the “full up” position to the underside of your baseboard, add 5 or 10 mm to this, it’ll be the length of your pusher.

Mark that distance below the half travel mark H. This will be below the baseboard and where your crank arm will be horizontal.

Decide how long you want your crank arm to be - a couple of times the travel is probably a good starting point.

Mark where your lever pivot will be, this distance from the vertical line and the same height.

Mark the other arm of your crank vertically from the pivot, (up or down) and that gives you the line of your operating rod.

hope this helps, if you need a diagram, I can do one for you.

 

[Osgood]

Cheap flexible choke or throttle cable assy attached to the vertical rod - direct motion from knob.
If you get a throttle cable assy for tipping the knob will have an engraved T
And if you couple the two rods for axle clamp magnets to one actuator and use a choke cable it will have C for CLAMP on it!

Edit: throw can be set by two simple stop collars on rods or cables.

If you wish to automate you could make up a cam assembly under the three rods so when turned it pushes both clamp (magnet) rods up first then the tipping rod up and down and then lowers the clamp rods.
Clamp rods need to be sprung to pull off axle magnets.

 

[Dave]

Thanks for the help, chaps, but I seem to have sorted it. It's not elegant but it works.

I found a plastic-bodied gearbox with a built-in 3v motor that I purchased from Squires at an exhibition, years ago. Just for this sort of thing, I should imagine but I must have stashed it away and forgotten all about it. I made a fitting to go onto the output shaft and soldered a length of brass channel to it. A slot was filed into the channel and the operating rod slides inside the channel. The lower end of the operating rod has a pair of plastic beads glued over a narrowed area and the channel engages with these. I jury-rigged the motor/gearbox and it works. At the moment the up stroke is terminated by the bead hitting the guide tube that goes through the baseboard and the down stroke by the wire around the end of the slot in the channel catching the gap between the beads and stalling the motor, but I will probably fit microswitches to cut the power. If I was really clever, which I'm not, I would arrange microswitches in such a way that a single push of a button would set the motor on the up stroke and return it to its start point at the end of the down stroke, ready to go again when the next car is positioned.