Hydraulic rams

smegballs · World Chat Champion Joined: 28 Oct 2007 Karma :

How long do they take to leak down the pressure?

Today I saw a cherry picker type machine with its boom up in the air just left on a site without its generator running. I also see JCB's left with the front loader up in the air parked up.

Is there any danger of a sudden leakdown and collapse of the ram?

Frost · World Chat Champion Joined: 26 May 2004 Karma :

No. Just like if you fill an air compressor with air and then turn it off, it won't suddenly discharge. It probably will discharge but at a very slow rate.

MarJay · But it's British! Joined: 15 Sep 2003 Karma :

stinkwheel · Bovine Proctologist Joined: 12 Jul 2004 Karma :

Shouldn't happen but can happen.

My Dad used to be in the lifting equipment business. They were out proof-loading a telescopic crane (to 3x safe working load).

The crane lifted the load just off the ground as instructed and started to pivot with it. At that point, one of the hydraulic rams in an outrigger abruptly collapsed.

250 tonnes went "Boing" on the end of 4-falls of wire rope. The jib went "ping, ping, ping." as it snapped in three places and the whole thing sort of folded in on itself.

My Dad issued an invoice for the test and a fail certificate.
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Raffles · World Chat Champion Joined: 14 Apr 2009 Karma :

chris-red · Have you considered a TDM? Joined: 21 Sep 2005 Karma :

They do it onsite to stop kids getting on them, leave them up the top by the building then climb through the building to get down.
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warped one · Banned Joined: 25 Dec 2007 Karma :

Sorry Sugartits, but that is abit of a farce.

I've often been on site and used the auxillary controls under the generator cover. They have in total 3 sets of controls. 1 in the basket, 2 under the cover. 1 is normal controls and the other is hand pumps and valves to move the basket in and emergency and stop kids like you said.

Working on the big sites such a Kier, Elmer, Magnus, Gualiford try, ect. They give you a yellow card for not having any gloves on and if your caught again they throw you off for the day. I highly doubt that they would openly let you climb out of the basket on say the 3rd floor.

Warped
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smegballs · World Chat Champion Joined: 28 Oct 2007 Karma :

Thanks for the replies guys.

Hydraulic systems are one of of the few systems I don't really know about, apart from brakes!

Pete. · Super Spammer Joined: 22 Aug 2006 Karma :

A hydraulic cylinder in good condition will not bypass oil internally. If you get cylinder creep it's usually in the controlling valves. Some cylinders are fitted with check-valves so that they cannot creep and won't move until the valve cracking-pressure is exceeded deliberately in operation. We use these at work for our machine-mounted rock drills.

As warped said if you climb out of an elevated boom type mobile elevated working platform you'll be committing a serious breach of safety regs. You have to wear a harness in a boom type MEWP with a restraint short enough to stop you being able to climb over the rail. This doesn't apply to scissor-type platforms which are designed to allow you to move around but you still mustn't climb out of them when elevated.

The reason they park them elevated is because they use up far less floor space compared to when they are fully descended.
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Raffles · World Chat Champion Joined: 14 Apr 2009 Karma :

warped one · Banned Joined: 25 Dec 2007 Karma :

CHR15 - That is a very dangerous thing to do. You should always carry someone else's if you don't have 1 Mr. Green

Raffles - I had a boom get mardy with me on the daul carrage way going through centeral Leicester. Was quite funny having a few quys stuck up in the air and the generator refusing to start. Had to play around with the manual valves to get them down to the ground. Bloody commuters sat right behind me beeping and swearing at me. Which obviously made it take longer to do.

Warped
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