Speed of lowering a hydraulic lift 1

[WARose]

I don't know if this is the right board to ask this question......but here goes:

I bought this thing recently:

https://www.youtube.com/watch?v=C0972yWbbas

The instruction manual says the time it should take to lower (from a raised height of 18") is 18 seconds. It says to adjust to match that.

Mine is taking 12 seconds. So my question is: is there any harm in keeping it that way? (Especially if it is always unloaded when lowering.) Would it hurt the hydraulics?

I just don't want to mess around with the settings of this thing unless it is necessary.

 

[Compositepro]

Its not a problem for the hydraulics, it is a safety concern. The 18" in 18 seconds is silly, but it covers their ass for liability. It also probably is meant to apply when the platform is unloaded. Speed will increase with load. Going slow just makes it less likely you will lower onto someone's foot or have some other accident. It also increases controllability.

 

[MintJulep]

Especially if it is always unloaded when lowering.

How does it know that it's unloaded?

There is no interlock, so the only way is by "procedure".

 

[WARose]

How does it know that it's unloaded?

There is no interlock, so the only way is by "procedure".

Don't know. (Which is why I am asking.) I provided that bit of info to see if that made any difference. The manual says nothing about whether the speed should be with it loaded or unloaded. It just gives a speed. And I am trying to guess why and if it can be faster without wrecking the hydraulics.

 

[MintJulep]

It is unlikely that the speed of the decent will damage the (unknown to us here on the web) hydraulics.

What happens at the bottom, when the load (or lack of load) comes to an abrupt (or cushioned?) stop may damage something.

From the Grainger page for the part number given in the linked YouTube: Country of Origin Unknown. Country of Origin is subject to change.

Although the Wesco site

https://catalog.wescomfg.com/item/lift-equipment/steel-pedalifts-winch-hydraulic/260002-1#

claims "Made in the USA (of US and imported parts)"

Is there a hydraulic schematic in the manual?

 

[MintJulep]

Plenty of car jacks where the speed of decent is controlled by how far you twist the handle.

How is the lowering speed adjusted?

 

[WARose]

What happens at the bottom, when the load (or lack of load) comes to an abrupt (or cushioned?) stop may damage something.

Good point. That metal platform does come in contact with the framing underneath and/or the ground.

Is there a hydraulic schematic in the manual?

Appears to be. But since I am structural, I wouldn't know that for sure.

How is the lowering speed adjusted?

Appears to be a screw/bolt to turn.

 

[MintJulep]

If you actually want some help, post the schematic. Take some pictures of the thing and post them.

I have my imagination - because that's all you're giving me to work with.

 

[WARose]

If you actually want some help, post the schematic. Take some pictures of the thing and post them.

Will post the whole manual tomorrow.

As far as pics of the unit itself.....I can do that.....but that deal on YouTube (see my OP) is probably better than anything i could put up.

 

[LittleInch]

Well you will see fromt he video that wehn loaded it goes down a lot faster than when unloaded.

So if it's doing 1" a second without any weight on it it might well go twice or three times as fast when loaded.

form the video it looked like unloaded ( when the employee had jumped off) it was about 1" per second

Then you take your foot off the valve and it stops dead.

Kinetic energy is velocity squared so three times as fast is 9 times the energy that the unit is mechanically designed for.

So hydraulically it might cause erosion in your piping system or result in high velocities squirting into the tank, but the mechanical aspects of the sudden stopping of the lift are what you want to try and avoid.

It should be a simple bolt / screw in adjustment. Screw it in and it goes slower, screw it out and it goes faster.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[WARose]

Ok, as promised, attached is the manual. The hydraulic schematic is on p. 6 of 7.

 

[hydtools]

Leaving it as is is not a problem. It will not harm the hydraulics.

See page 4 for speed adjustment instructions.

Ted

 

[LittleInch]

I just don't understand your reluctance to adjust this? The process is very simple as outlined in page 4.

The recommended speed is there for a reason.

No one here is able to double guess this. Just do what it says to do. Problem solved.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MintJulep]

The instructions on page 4 say that you can set the lowering speed to whatever you want.

 

[WARose]

I just don't understand your reluctance to adjust this?

It comes from experience. Yes it looks simple.....but that's famous last words with a lot of these manuals.

 

[WARose]

The instructions on page 4 say that you can set the lowering speed to whatever you want.

That's not the way I am reading it. It says: "If time is less than 18 seconds, turn set screw in 1/4 turn clockwise increments until slower speed is reached. Turn counterclockwise if time is greater than 18 seconds, if a faster speed is desired."

That tells me that you can only go faster if the lowering speed is greater than that 18 second target.

 

[Jboggs]

So the descent time as this unit was built by the factory happens to be 12 seconds. So that should be ok. I don't see anything in the instructions above that set any speed limits. It all gets down to the load you will be handling and how gently you want to treat it. There's nothing in the hydraulic system that you're going to damage by going faster or slower. I think you could damage the mechanical structure (from high speed impact) before you would damage the hydraulics.

Don't be afraid of it. Play with it and set it where you like it.

 

[WARose]

Thanks Jboggs.

 

[Compositepro]

Well one concern would be the hydraulic pressure generated by closing the lowering valve too suddenly. The speed restriction could be because they saved money by not having any pressure relief valve.