Looking For Scale Clamshell Bucket Plans
 

Hello:

This is my first post. I’d like to retrofit a Huina 1:14 scale RC tracked crane with a clamshell bucket. Preferably I’d like a bucket that opens & closes automatically, similar to the type used on Tonka & Nylint toy cranes. Apparently the toy buckets use a simple sliding mechanism that closes the bucket automatically when a load is lifted, then opens it when a release trigger on the bucket hits the boom at the top of its travel. The attached photos show details.

Tonka & Nylint buckets are too big & toylike to look right, plus they’re far too expensive to buy just to reverse engineer the open/close mechanism. Does anyone know if plans are available to build scale model buckets fitted with an automatic open/close mechanism? If so, please let me know.

Thanks,
Pete

Re: Looking For Scale Clamshell Bucket Plans
 

Attachments don't work here, need to use a 3rd party image host.

Between my machines, i believe I've got a Tonka and Nylint clamshell i can get pics and measurements on for you. Clamshells need weight to work well.

If you run a Doepke, Tonka, Nylint style clam, and you've got an extra channel to put a servo on, you can attach a calming line to the release hook. Slack the Calming line, drop Hoist, take a bite, raise Hoist, move the load over, pull Calming line to dump. It's not as effective as running a Crowd line as a powered closer, but it works more consistantly than disk and triangle.

I suggest looking into how the real ones operate with lines for Hoist, Closeing, Calming. If you're able to do that it'll work much better than toy style of just hoisting until it hits the opening plate and the triangle kicks the closer hook free.

A patent search is usually good for some drawings you can use as patterns.

Nylint and Tonka have the 'triangle and a plate' to shift the floating hook and dump the bucket
http://www.tnttoytrucks.com/NYCONDiggers.html
Sometimes it even works.

Doepke used calming line release
http://www.tnttoytrucks.com/DPKUnit1.html

Re: Looking For Scale Clamshell Bucket Plans
 

On a Nylint michigan crane, the disk at boom tip that the hoist line passes through is 1" diameter. Tonka probably wider due to more distance between lifting eye to triangle tip?

They both use a U shape profile up the center frame to hold a lifting hook slider. Nylint slider hooks lower edge of U, Tonka slider hooks center pin between jaws.

On a Nylint michigan clam (black)
Center pivot to side link 2"
Side link length 3.750". (4 Seperate links)
Center pivot to dig tip 2.400"
Center to end of inner frame travel 4.800"
Jaw width 2"

On a Tonka 'something' clam (silver) that came with my doepke Unit
Center to side link 2.100"
Side link 2.850" (2 A-arm looking links)
Center to dig tip 2"
Center to inner frame travel 3.650"
Jaw width 2.110"

Locked lifting config
https://i.imgur.com/UUZWCDch.jpg

Unlocked dumping / loading
https://i.imgur.com/dUBMzbNh.jpg

End view
https://i.imgur.com/ZqhW9Iyh.jpg

Lift hook and calming/release cable
https://i.imgur.com/fODmWExh.jpg

Nearly 60 year old toys, stampings, rivets, rust...tolerances aren't precise even though i tried to be.

Re: Looking For Scale Clamshell Bucket Plans
 

I had a Tonka clamshell crane as a kid and like Frizzen said it barely worked. At least that's what I remember. Anyway here is a different design that MIGHT be more reliable.
http://www.alansmeccano.org/models/triang.htm

Hope this helps.

Re: Looking For Scale Clamshell Bucket Plans
 

When I get a chance I can scan some stuff from my extensive crane literature collection. Or PM me with an email.

Re: Looking For Scale Clamshell Bucket Plans
 

I'm in the same boat, I have a Nylint Michigan crane that I want to get the clam bucket to work. RvJimd did a video on a scratch build he did with a lot of the issues he ran into ( I don't have a link sorry), Like Frizzen said it has to be pretty heavy to work.

Re: Looking For Scale Clamshell Bucket Plans
 

I can't wait to see what cool reference stuff comes out of the 9w collection!

You got me thinking why not try to convert a Nylint clamshell bucket, using as much of the stuff removed during the rc conversion of my Nylint. What could it look like if the factory were to have made one more complicated?

https://i.imgur.com/k2gc20Fh.jpg

This uses the original tip mounted Hoist line pulley moved to the top between the 4 links, brass axle with lifting loop, and a cable guide with a W shape. Then the Boom angle pulley was removed from its bracket and installed with spacers at the bucket fulcrum. The buckets closer line ties off at the top axle, runs below the bucket hinge pulley, then up around the top pulley, to the cable guide and a ring where the Crowd line attaches.

https://i.imgur.com/xkaZxc0h.jpg

https://i.imgur.com/RyARCINh.jpg

Then i ran a Calming line from one of the buckets links, around a pin on the boom, to a fishing weight. It just needs enough weight to keep the bucket from rotating and tangling the lines, and enough length for the needed vertical travel.

Here's what the Nylint center close & lift pieces look like.

https://i.imgur.com/UAIqldjh.jpg

Thanks to truckmaker for the crane he sold me still having the clam so i could do this.