Hmmm... thought I put up a post yesterday (even got a response notice in my e-mail) but it is gone today... Anyway....

It is awesome to be able to talk with experts!!!!!

In my sketch of a new hydraulic system, I put in what I called an "unloader" valve. It would be a normally open valve just after the pump ( along with a relieve valve ), that would let the motor start with no load. After the pump runs for a few seconds, I would close it and energize the system. I did this because we design air compressors in the same way ( worked for a custom air/vacuum shop as head designer for 5 years).

I found it odd that I did not see such a circuit on the forklift. I did not imagine that having the switch make just before opening the spool valve would accomplish the same thing. Thanks for the insight!!!

As for speed control, I faced this problem when I worked for Westinghouse (about 10 or 15 years ago). We had a custom built lift to stand the "bundles" from horizontal to vertical. Then the ram reached the top of the lift and the solenoid valve shut, the "jerk" caused the bundle to move around a bit (lift unit was 20 ft long). This cause no problems but it was pointed out that our customers did not like to see there units being "bounded around".

To solve this I installed a proportional flow valve in line connected to PLC. At the beginning of the lift, I simply ramped up the valve from 4 to 20 mA over a few seconds. When I was nearing the top of the lift ( had a proximity switch sense this), I reversed the action, slowing the unit down till it gently came to a stop and "locked in".

I would like to do the same thing here. Automation Direct has some reasonable priced PLC's. My big expense I think will be the proportional flow valve.

I did think about three parallel solenoid valves each with a flow control valve. I could have all three open untill just at the top. I would then shut down one then a second. This would "step" the unit to a slower speed. I think though that by the time I buy three solenoid valves, three control valve and switches, I will be up to the same price as a proportional valve.

As I said the model # of my machine is 20R30TN

The serial # is 020-82-21354

Thanks so much !!!!!!!!!!!!!!!!!!!!

Mike

the microswitch for lift closes before hydraulic oil flows through the spool causing the motor to turn on but just bypass. you can control lifting speed depending on how far the plunger gets pushed in on the spool valve. (2-way valve you called it)
typical pressure relief settings is from 2000-2500 psi.

I will get the serial # off the mast tomorrow. Today I finished disassembling the mast and with the help of a skid loader moved it into the house.

The lift does not seem to have a speed control on it. There is only a 2-way valve which is directly operated by a lever. It has a set of contacts on it which start the pump motor when in the lift position.

What is the relief valve set point on the lift hydraulic system? I am planning to use the original motor and pump but will do away with the control block that has solenoids and pressure relief valves mounted in it. I am planning to just use solenoid valves to raise and lower the cylinder.

One question I have is why use an "up" valve at all? If the pump does not start until the valve is pushed into the "on" position, and there is a check valve so fluid cannot leak back when the pump is not running, is the "up" valve not redundant?

Thanks so much,
Mike

I have books on the TT model (3 section mast) but it does not show any other masts. Most everything else should be the same, pump, valves, carriage. I can send you breakdown diagrams and part numbers of anything other than that low mast, if needed. What's the serial # of that machine? Does it use a master cylinder with brake fluid and lever, and a slave cylinder on the pump to control the lift speed?

i get it, like you said nobody needs to know what your gonna do with the parts and even so what are you going to do build a bomb? crazy days.
your bang on, its a one way flow control. on the model 20s they rarely fail.
you should know they are designed for a load on the forks of 3000lbs, they come down rather fast unloaded. downdrift is going to be your enemy after your on the second floor for a couple of hours with the model 20's hydraulics. they all downdrift somewhat. your going to have to build a new hydraulic system for this to be a success i don't see how you can make it useable with the current manual spool system. i would want a solenoid system with controls on the house walls upstairs, downstairs and on the car. you got your hands full here.

Interesting that you mention there low lift... I actually had a problem finding a "small" unit that lifted this high. I have 9 ft ceilings ( so I can put an overhead track lift in for transferring from the wheelchair to the bed and bath) plus 12 ( well actually 14 with sub floor and flooring) inches of joists. I needed about 10ft 2" of lift. I measured this unit at 10 ft 8".... just enough for my needs.

The "local" forklift service is toyotalift... they seemed very friendly but didn't have the manual for this machine ( they had the service contract for it the factory I got if from but it was a seldom used machine and it looks like they just did the basic battery check, grease and oil a few times a year on it).

I looked up Able Womack.... looks like a huge company. I can give them a try but it has been my experience that most large shops don't like dealing with the "small fry" like myself. I have always been just a one man business and understandably most large shops cater to large factories.

Also, I am not blind to the fact that most companies would not even want to talk with me if explain I am using this as a elevator. Lawyers have scared everyone. When I did work for Westinghouse, they required 10 million minimum insurance. As a one person company, this almost killed me. My insurance typically cost me %20 of my gross profits!

I don't mind taking responsibility for my lift since it will be for personal use only. Even the local inspector didn't care... he said the same thing. If it is commercial or public use it comes under the Fire Marshal. For our own use... you can build what you want. No one but my wife and I will ever ride on it. I will keep it "locked out" when not in use "just in case".

I am hoping that by getting a manual and knowing all the parts I need, I can just order parts from any dealer. They need not know what they are going on... I am sure they will just assume it is for the Raymond lift.

I figure at this point, just asking how to dismantle it and find part numbers and parts, everyone should still be OK. I am not asking for any advice on how to build the elevator... just trying to understand the original forklift.

I actually ran into this problem a few times now try to fix a hoyer lift and a stair lift for an elderly couple. They had no insurance that would cover the repair and could not afford the $100 per hour charge (4 hour minimum) for the local repair guy. In both cases it was a simple problem. They local rep and the factory would not sell me the parts to fix them. For one item I was able to order it when I told them I was a business that installed and repaired medical equipment (sure a machine shop can do that). For the other, they would not sell it to me no mater what... sales and service only through the local rep. I ended up making the part... took less than an hour. I just felt so sorry for this couple and I am sure there is many more like them out there.

Anyway, I got the mast off during a snow storm the other day ( fun).

I just took off what I assumed was a fitting at the back of the cylinder ( badly corroded most likely from battery acid dripping on it at some point in its life).

I see it more that a fitting. can I assume this is some sort of check valve / limiter. I am guessing it lets full flow in one direction ( raising the cylinder ) and yet limits the flow in the other direction ( limiting the speed when lowering the unit). Is this correct?

Again, here is where I need a manual. This unit works but since it is in rough shape, I would like to replace it. I need a part number.

Also, just for my own education, is this a common hydraulic part? Do I need to get it from a fork lift dealer or can I get this part from anyone who sells hydraulic parts?

Thanks so much again..... Mike

Thanks again..... Mike

imo you should contact the local dealer. ablw womack is listed as your local raymond dealer. (877) 989-9570. if you have the model and serial number for the truck they should be able to get all the parts your looking for. make sure you stress you have a TN, the nominal mast your truck has is not to common. and your right, those welded pins are dowel pins.

i still service fleets of these trucks, but tt's (triple masts) the nominals were always scrap/parts worthy due to their low lifting heights.

email me exactly what you need

Hello!

Really, I am only interested in the "lifting" parts of the unit.

I am trying to get a list of parts that make up the mast ( really only the guide rollers, chain and cylinder seals ) and the lift hydraulics ( motor, pump, valves ect.) I want to replace any worn parts now and then stock pile any parts that may wear in the future.

My wife is paralyzed from the shoulders down and confined to an electric wheelchair. I need an elevator to get her upstairs.

A commercial unit is $40K! Way out of our price range. I bought this unit for $850 and it was in service till last week. I figure for about $4K, I should be able to build a lift ( about 10% of the cost of buying a unit). We were told we could get a grant for an elevator once the house was done ( building area was small and lent itself to a two story home also it was cheaper to build up than out). Now we are told the grant is only for $5K max. We borrowed to our limit to build the house and don't have $35K more for the elevator.

A hydraulic lift is ideal. Even if lines break or seals fail, it will come down safely ( I will put a limiter on the cylinder in case the line breaks). I runs on batteries so it will work if the power fails. All I need is to put a battery minder on the batteries. It will most likely get use for 2 to 5 minutes per day ( very low service factor). My max load will be 600 lbs ( wife, me and the chair... although I want to set it up so she can use it by herself.. so say 400 lbs).

I am a machinist so the mounting of the mast and fabricating of a car is no problem.

I worked for 10 years as a consultant at Westinghouse Nuclear so I am very aware of the safety concerns of a lifting device ( safety switches, door interlocks, pinch points,....).

I have just never worked on a forklift before ( really the only hydraulics I have done is a log splitter and modifying a machine at Westinghouse... put a proportional valve on a lift with a plc to slow the lift and gently stop the unit rather than a hard "bounce at the end of a lift).

You could also send us a little "warmth" up here in VT... I am stripping this unit outside in sub zero weather. We poured the pad for my new shop but we had to delay putting it up till spring.

Just FYI... here is motor home I modified my wife could travel ( she needs care every 4 hours). You can see the lift I build on it. We are living in it till the house is done ( motor homes are not meant for VT winters).

http://mcsele.shutterfly.com/2299

I appreciate any advice you can give.

Thanks..... Mike

It is kinda simple. Once overmast cables and hoses are disconnected. Of course carriage off. In battery box, if memory serves me, there are 8 bolts holding upright to chassis. I do have a hard copy manual, what do you need?