Getting a screw type car lift / ramp back into service

[Quietcountrylad]

Hi , just seeing if I can get some info re screw type car lifts / ramps.

I bought a used Werther 253 screw type car lift / ramp ( built circa 2000 ) a few months ago. Ramp was bought as a non runner from a main dealer for reasonable ish money. Have previously used a Chinese built hydraulic two post lift , I'm unfamiliar with screw type lifts.

Known issues ; bad motor

Possible issues ; was told lift nuts may need replacing.

Plan ; check for wear on main nuts , replace 4KW three phase motor with a single phase reversible 750w motor and reduction gearbox from a winch ( she'll be slow )

Ramp is now assembled and ready to test.

Wondering how best to test if the lift nuts need replacing? And what's the allowable wear limit?

Also the screws do not rotate by hand , presumably due to a mechanical break , how is this released for testing? And how to check if it's in good working order?

Also anything else that needs checking on this type of lift?

Thanks again

 

[frank horton]

OK, there are 2 kinds'a nuts....plastic and bronze.......if all the arms are fitted and the lift is in the upright position u'll need to put a spanner on the pulley to get it turning........
assuming the chain is connected it'll move both sides.......I know this cos to fit the new belts on mine I have to rotate the pulley to get em on.....they are slightly tight.....
I dont know of any ramp with an electric brake.....but then I'm an ol git........hahaha........

as for wear in ya nuts.....back to the material again.....if bronze absolute max would be 0.5mm of slack or lift for plastic 1/2 of that amount.....best measured when the ramp is laying on it's back.......so there's no real load on the carriage/nuts......never bought the plastic nuts but bronze are any where from £60 -£400 each.....yep thats right, depends on manufacturer......there are repair parts on line in Germany that are copies.....poss UK, I don't kow.....
take great care to inspect the screw threads in the tower......any damage or rust will trash the nuts...old or new.....have seen em with hammer marks.....

all lifts I install for myself are stripped out and individually wound up and down by hand......only nec because I dont know their history.....

so, on my spare lift the factory nuts are €650 euro's each + tax......unavalable anywhere else so bought a lump of Bronze to make my own..the bronze cost £180 english....enough for 2 new nuts.......oh it's a special bronze, cant remember the grade right now.......
just gotta make em now when I get time......this ramp got scrapped cos some idiot had done away with the auto stop mechanism and another idiot crashed the ramp into the top bearing stripping the threads in the nut.....

also most ramps now have a saftey nut...this carries no weight at all until a main nut strips...... these safty nuts just follow behind, as the ramp goes up and down.....
BUT THEY ALSO WEAR.....on mine 1 is quite worn but will make 2 new 1's......on this ramp these saf/nuts are made from steel plate (40mm thick) so material is cheap.....
saftety nuts from the German supplier are €85 euro's each.......needles to say I'll make my own......
another thing did u check the chain ? they can get tight spots in em.....new chain is very cheap of ebay...u buy a 20 -25ft length.....about £20'ish.....

so does ur limit switches work......mine dont but it's only me that uses the ramp......!!!!!!!!!!!

not sure how u'll get on with sutch a small motor.......mines 3phase and struggles a bit at 3 ton.......actually I made a new top pulley (large 1) to alter the gearing slightly....now lifts the heavy stuff without probs.......

so for lube I have always used chain saw oil, that the sticky oil just for the chain.......I just dribbel some of this oil on the screw with a squezzy bottle ( not a lot) and let it wipe the oil as the ramp gets used.....
have done this over 15 years with this ramp.....plastic nuts...and all's perfect.......with this oil when the screws get power'd up they dont fling oil everywhere like the normal oil, even gear oil....
anything esle just ask........

 

[Quietcountrylad]

Hi thanks very much for getting back to me, you have raised a few valid points.

On the lift I have bought there appears to be no safety cable or chain and it doesn't appear to have anywhere to put them , so I'm reasoning it relys on the nut and safety nut.

The driven and slave screws are connected via a pair or 90° gearboxes and a shaft , I removed these when I was removing the lift. I was under a bit of time pressure to get the lift removed so I didn't mark which was which but they appear to be identical boxes. They appear to be in reasonable condition. With one having a little bit of a growel , but nonetheless appears serviceable.

I also had a look at the screws, they appear to be in good condition with no obvious damage or rust.

I have managed to price replacement load nuts and they are not so bad at less than £100 each , bronze nuts ( still a lot more than I had guessed but not terrible considering what you were saying or by the price of some others listed )

I'm thinking the next step is to wind the screws to the bottom of their travel , unbolt the nuts and assess the amount of wear in the nuts.

I'll hopefully get stuck into it next week and I'll let you know how I get on

Thanks again