Cut the gussets for the legs since i have this chunk of 3/8 i got for free sitting in my
Way.

View attachment A1D387A2-EEB0-4D7E-8136-AF2665539D5D.jpg View attachment B013437A-9DE5-44F6-BBD8-927147983674.jpg

 

Disclaimer: Everything i know on this subject was learned in the past 2 weeks. I’m open to all criticism.

Decided I want to learn more about hydraulics, so I am going to replace my 20t
Swag off-road finger brake (19” long) with a 36” long capacity.

Rounding up it will have 40Tons of downforce. Powered by a car lift power unit at 2950psi.

Main parts are 1” X 6” cold rolled. The middle of the press blade is 10” to the top of the hat shape. It “should” be grossly overbuilt”

I drew this design from from the ground up with my limited knowledge on the subject.

The biggest hurdle is timing the cylinders, I’m not going for extreme precision but I do want it pretty good. I plan to use a geared flow divider to hopefully Achieve “good enough.”

Stroke will be 6”, no need for it to be that long but it gives me the option to move the blade out of my way.

Anyway, stay tuned. Steel is ordered.

I estimate the project to cost about $3000 and whatever after for tooling etc.

Looks like a nice project.

-Don

 

The trick to "timing" the cylinders is a rotary flow divider,,
I guess you need the tiniest one that you can find,,

AND,, the answer is "NO" to the cheap divider,, as well as parallel connecting.

It is too late for the other method,, that is connecting two cylinders in series,,
because, for that, I believe the cylinders need to be different sizes,,
I have seen that done on some sort of farm equipment.

 

Yep that’s the plan, it’s about $500 for the divider.

 

one thing i have learned as well from college studies that covered hydraulics and pneumatics is you want your hoses to be the same length, even if it means putting a loop in one. as the different in length of the hose/ pipework can throw off your timing a little.

although hydraulic fluid is is generally regraded as incompressable it does have a very very small amount of give so the length of hose has to be factored into you timing question

 

A divider is one way as it looks too late for rephasing cylinders. As ghost said hose length is critical.

 

If you can add an adjustment to move the cylinder up and down on one side as opposed to bleeding one side it will save you a lot of headaches.

 

Not sure what you mean. They would need to be bled again after the initial setup?

The rotary setups are that ****ty?

If there’s no chance the divider works I can scrap the idea… everything thus far is returnable steel isn’t delivered till Monday.

I was told putting the cylinders in series would not be accurate enough on another group.

 

I saw a nice one at auction a while back 75T, 800$ Aint no way I would build it today before I looked, maybe even new at that cost. I did one but,,, I needed it, did in a day, had it all in stock for free. Not as sophisticated, simple press.

 

From my experience they go out of adjustment easier than they stay in. Any small leakage past the piston on one side will throw out your ram after enough cycles. If keeping the ram and bed parallel is important adding a way to compensate the stroke length on one side would be helpful.

 

I mean, do you think I should abandon ship on the idea? I was hoping over a short span it wouldn’t be an issue but i have no experience here at all.

 

Your cylinders are relatively small to think some adjustment will not be needed,,

Heck, even a minor variation in material thickness of the part being bent can cause one side to be "out of time" with the other side.

A huge volume is needed to compensate for all the possible "changes" that can occur,,

An adjustment on one of the cylinder lengths will correct all of the issues.

The real answer is going to have to be change to one big cylinder,,
or,, move both cylinders to the center, one front, one back,, so that the cylinders are forced to work together.

 

Alright i guess it’s back to the drawing board…

 

Have you thought about something like this?




https://www.pirate4x4.com/cdn-cgi/i...ments/torchmate-cnc-forum/784650d1362713364-48-press-brake-project-pc100004.jpg

 

I'm actually sitting here right now seeing how to redesign it to that style.

 

The big concern at this point seems to be that uneven forces under the brake will cause the 2 cylinders to respond unevenly. On this short distance (from one side to the other) the force differences will be minimal, so why not just prevent the brake from coming down unevenly and forget about the expensive hydraulics? I'm thinking a frame on each end with 4 rollers to run on the press frame so the hydraulic force is all directed straight down, and can't twist from end to end. I see differences on a 40 foot machine with multiple cylinders, but for just 2 this close together it shouldn't be a big deal. I've also worked on implements with multiple cylinders plumbed in series and I wouldn't recommend it as a solution. They work great new, but any air or leakage makes them more wonky than the ones plumbed in parallel.

 

Deep in it now. My Brain hurts.

Ignore the cylinder mounting.

View attachment 06684B3E-CD9D-455B-AA71-8DC96FC3DA5E.jpg

 

A torque tube will keep blade straight

Dave

Disclaimer: Everything i know on this subject was learned in the past 2 weeks. I’m open to all criticism.

Decided I want to learn more about hydraulics, so I am going to replace my 20t
Swag off-road finger brake (19” long) with a 36” long capacity.

Rounding up it will have 40Tons of downforce. Powered by a car lift power unit at 2950psi.

Main parts are 1” X 6” cold rolled. The middle of the press blade is 10” to the top of the hat shape. It “should” be grossly overbuilt”

I drew this design from from the ground up with my limited knowledge on the subject.

The biggest hurdle is timing the cylinders, I’m not going for extreme precision but I do want it pretty good. I plan to use a geared flow divider to hopefully Achieve “good enough.”

Stroke will be 6”, no need for it to be that long but it gives me the option to move the blade out of my way.

Anyway, stay tuned. Steel is ordered.

I estimate the project to cost about $3000 and whatever after for tooling etc.

View attachment 1735055
View attachment 1735056
View attachment 1735057

 

If you plan on using cold roll plate, I'd just forget it. You don't need it. The bit of additional tensile, and yield, strength, in the plane you're working with, isn't worth the additional cost.

 

It was for the square clean edges vs the bullnose of hot rolled.

 

I have a Promecam 35T single ram upstroking pressbrake... all I have to do is make sure I use the centre of the brake for everything, and I get perfect bends even over 2m lengths. I set all my tooling clamps with a DTI.
You know about it if you try to use it to one side... the upstroking bottom die goes on the wonk.
I think you'd be OK with the design as it is, provided you use a flow divider and equal length hoses. And then use the centre of the press for everything.
You will need some form of fine adjustment in either the top or the bottom, just to get it perfect. So the hydraulics do their thing once bled.

Its hard to want to go backwards once you've used a proper press though... setting the travel limit on the brake to acheive the same bend time after time again, and just positioning the metal and stomping, is pretty sweet.

 

I use a swag offroad press currently and its the same thing. You MUST be in the middle if you're bending anything beyond printer paper.

Repeatable bends are non existent with the swag, primarily because the die is free to float in the press.

 

If you NEED square edges for fitment.....................price mild steel, and what it would cost to take it to a shop to have one edge, or whatever # of edges milled. Might save a boatload of money.

 

When you get to the point of forming find your center point and put two stick on inch tapes out from there. It make it easy to center parts.

 

What if you made one side mechanically adjustable (still with two cylinders) just in case one side is slightly off, you'd still be able to fine tune it.

 

Just thinking. and probably this wouldn't work anyway
How about just using a two bank system with two separate levers. Hold both down at once or one at a time

 

Would never work. Same issues exist and then human error is added.


This is the best I got... This took like 3 hours if it doesn't work I give up.

The link between pivots is adjustable in length like a sway bar.

View attachment Hydraulic Press Brake (v46~recovered).jpg View attachment Hydraulic Press Brake (v47red).jpg

 

the are many plans for cantilevered press on the wed to give you ideas for your own design.
https://www.pinterest.com/pin/327073991693813887/
https://www.pinterest.com/pin/476818679267401227/

 

That's not a bad design as long as the link rod is adjustable.

 

I ran out of energy to draw it.

It will be like a sway bar/turnbuckle

 

I understand. Too much computer time makes your head spin!

 

That's a great design, but make sure the knuckles and pivots can cope with 20t of repeated force. The pins want to be 2" dia minimum imo.
Putting a 1" link rod with a turnbuckle in is a great way to get it set parallel, I like it.

I still like a dual ram split flow design better though.
What about spring return?
An up stroking design is self returning. That design would have to use springs I think? Or a 2 way ram.

 

The two ram design isn’t guaranteed to go down evenly is the issue. And likely won’t.

The pins on the hydraulic cylinders are 1” i don’t think there will be any issue. Many designs I’ve seen use 1” pins.

I’m going to put them in bushings as well for longevity and replaceability

The sides are 3x5 1/4” tube and the horizontal plates are 1/2” on either side. You guys think that’s strong enough?



Added the adjustable linkage. 1" thread

View attachment Hydraulic Press Brake v51.jpg

 

Drew everything with shaft collars id assume theyre superior to cotter pins.

Not sure what steel to actually use for making the pins. Is regular 1" cold rolled sufficient or do I need a hardened pin?
View attachment Press 1.jpg