Thread: Hydraulics Question

hi you should be able to achieve 50/50 flow using a stander two way directional valves and tee fitting on the cylinder as the fluid will as you say o the the side with least resistant and should always power both cylinder equally. if your interested i have a power PAC minus the take which i was looking at selling

The force applied by the ram(s) is a function of the piston surface area and the applied fluid pressure. For comparative purposes, a ram rated at 20 tons force at a given operating pressure will have twice the piston surface area of one rated at 10 tons force at the same pressure.

Likewise, two parallel 10 ton rams would require the same fluid movement as a a single 20 ton ram to move the same distance at the same pressure, so concerns about a dual ram setup moving at half the speed of a single ram setup are unfounded.

The main concern would be balancing the load to ensure that the fixed and moving tooling remains parallel at all times. Commercial units with twin rams generally use a torsion bar setup to equalise force and travel. Without this, the user would need to ensure that the applied loads were evenly placed and balanced along the press at all times, i.e no setting up for multiple jobs by distributing the tooling along the length of the machine, individual jobs need to be force centred around the midpoint.

I doubt that a PS pump would give an efficient 20 ton force, as I doubt that they can achieve sufficient flow rates. They could probably generate the force, but with fairly slow travel rates. This might not be an issue except in an emergency where being able to release the tool quickly would be critical (assumes that you intend to use double acting cylinders rather than spring return systems and single acting cylinders).

HI,
I very much doubt that a Power Steering Pump would work. I think You need two 20 Rams to get the 20 Ton Force. Reason being when You think about it, when You have two 10 Ton Rams pushing down on one thing it is still only 10 Ton of Force. You will find though that a Double Ram set up will perform a lot better than a Single Ram set up. If there is any increase in Pressure with a Dual 10 Ton Ram set up, I don't believe the output would be any more than 15 Ton. I could be wrong though it just My thoughts.

This Quote I don't understand - so concerns about a dual ram setup moving at half the speed of a single ram setup are unfounded.

I did see on 'eBAY' Last Year a Home Made Press Brake that a Melbourne Trailer Manufacturer was Selling. It was using from Memory two 12 Ton Air Hydraulic Bottle Jacks (their Airline was linked Together). It had been used for Bending Sheet Metal including Checker Plate. I think I downloaded the Pictures of it off eBay, I will have a look over the Weekend and see if I can find them. It is an Interesting Project You are undertaking all the same. I actually want to Build Myself a 30 Ton Work Shop Press with a Press Brake Attatchment to go with it hopefully this Year.
All The Best steran50 Stewart

The shortest way to do many things is to do only one thing at once.

HI,
I found the Pictures from eBAY that I said about here they are:
Attachment 137704

Attachment 137705

Attachment 137706

I hope they work, it's the first time I have uploaded pictures to Woodwork Forums.

All The Best steran50 Stewart

The shortest way to do many things is to do only one thing at once.

Sure didn't waste money on tooling on it, a bit of angle iron for the V Tool, fixed in place by welding to a nut in each corner, no edge support in the rest of the span. Obviously didn't have high expectations and probably didn't meet them either.

To split flow to two cylinders without one cylinder being favoured you would need to use a pump with 2 separate circuits (2 pumps joined together) or a flow divider like this....

Flow Dividers

Alternatively you could use a set of phasing hydraulic cylinders. These are cylinders which are connected in series and sized so that the cylinders move at the same rate.

Thanks guys, will give me a bit more thinking to do yet.

Out of interest though, here is the tooling I have

Attachment 137765

Should do the job! Been quoted $350 for a gooseneck knife. Will look a bit harder at the clearance gear yet though.

HI BenM78,
I came across this Picture Yesterday, whilst searching for Pressbrakes and Workshop Press's and Inverted Bottle Jacks. I thought it might interest You. It looks like they have used proper Tooling for the bottom Die.
Attachment 138051

All The Best steran50 Stewart

The shortest way to do many thing things is to do only one thing at once.