Good day everybody. I have a 4 x 4 Mercedes tractor rigged with a Hiab 100AWV loader crane & a Rotzler hydraulic winch. It was professionally built in Sweden to be used in the powerline construction industry. With an estimated weight of 6 to 7 tons It has a twin pump that runs from the tractor PTO, one pump feeds the loader crane circuit and the other feeds the winch and outrigger circuit. The crane, winch and outriggers all function normally. The winch/outrigger circuit has a mechanical dump valve between the feed and return, located directly after the inline high pressure filter Each of the four outriggers is fitted with a XMJ-A160 pressure sensor. Each sensor (2 wires) is wired back to same junction box. Other connections going into this junction box are; Power in from dashboard Power out to winch control Power out to solenoid valve on the return line of the winch / outrigger circuit Within the junction box are block connectors and a contact switch and a small inline resistor and an earth connection. Some wires are cut and some are disconnected. Also with evidence of insect infestation. Can anybody help me with the following advice; How to rewire this system. How would this system work in theory and practice (I am assuming that it is a safety feature as the crane has a reach of about 11 meters) Any advise would be much appreciated. NB. The Rotzler winch return line configuration is not 100% accurate in this sketch. However there are 3 returns entering the tank. Thanks
PLEASE BE INFORMED - THE CIRCUIT DIAGRAM IS INCORRECT I WILL REVISE AND REPOST!!
From what I was able to scrounge off the internet, those are pressure switches vs sensors. It appears that they are adjustable limit switches between 15 and 160 bar. That kinda goes along with the 2 wires. Most sensors/ transducers are 3 wire. Unfortunately, this doesn't help with rewiring. Have you tried reaching out to the builder, they may have records from when they built it. Best of luck to you
Thanks for the response. I think they are sensors as they are only T'd off the circuit and have nothing that they can actually "switch". As I see it, the only thing they could perhaps do is send a signal to the dump solenoid for it to switch on or off.... I've attached the revised circuit sketch, perhaps their function may be more apparent after looking at that. I incorrectly recorded that the winch/outrigger return circuit was connected to the dump solenoid. On inspection today the dump solenoid is actually connected on the pressure side of the crane circuit......which confused me even further! Yes I have tried to find them but have had no response.....I also have a drawing here that the design was done in 1986!
Hello 'fun with diesel', with reference to your comment switch v sensor and after educating myself ......you are correct, they are switches. As you have probably guessed I am not a hydraulics guy and I am battling to understand how this system should work. Are you able to comment on my revised sketch? Does it appear to you to make sense from a practical point of view? 1) Could the pressure switches have something to do with monitoring a pressure build up due to a force being applied to the out riggers, perhaps when jibbing out too far? ...and if that is the case, when the set pressure is reached and the electric signal sent, what is its purpose? 2) What is the reason to have the crane circuit going direct to the solenoid valve on the tank? and What is the purpose of the solenoid valve? It is activated/deactivated by switching the ignition on or off. 3) The wiring from the pressure switches enters a common junction box along with the wires from the solenoid, could the pressure switches be supposed to talk with the solenoid valve?, and if so, what would that do, as they are on separate hydraulic circuits? The winch, out riggers and crane all work
I would agree with your thoughts. The pressure on the switch must disallow you from getting into trouble. For example if you were booming down with a fully extended boom, your tipping chances are greatly increased vs booming down with a retracted jib. Have you tried reaching out to HIAB specifically. They should be able to provide guidance on how they wanted their equipment installed. With cranes, we don't want to guess at all. Everyone has to go home safe.
Thanks for your interest....no, I've not contacted Hiab. I think they will consider it to be the problem of the system designer. After thinking more about it, I reckon that as more pressure is exerted on the outriggers due to a tipping moment on the machine, the increase in pressure reaches the set limit on the pressure switch and it will then activate an electrical current to the normally closed solenoid dump valve. Thus opening the dump valve on the crane circuit and therefore stopping the crane from further movement (or slowing it down). So I need to find out how to connect the four switches to the solenoid valve using the connector blocks, contact switch and resistor found in the common electrical junction box. Any suggestions? Should be quite a simple solution I think.
Don't assume anything for safety's sake. Reach out to HIAB , they make chassis mounted this and that. I would think that they will offer some assistance. They just won't help you with the Mercedes part of the machine.