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Bumper hydraulic pump

Discussion in 'Heavy Equipment' started by 77gmcserria, Sep 29, 2009.

  1. 77gmcserria

    77gmcserria Member
    from N/A
    Messages: 48

    Does anyone know how a hydraulic pump works that is connected to the crank shaft? I see them alot on cement mixers and trash trucks. It looks like the pump is sitting on the bumper.
     
  2. wild bill

    wild bill PlowSite.com Addict
    Messages: 1,239

    pump

    i believe they use load sensing hydraulics ,they pump when they sense a load on the hydraulics .
     
  3. 77gmcserria

    77gmcserria Member
    from N/A
    Messages: 48

    Does anyone have a pic of this set up and the connection to the motor?
     
  4. wild bill

    wild bill PlowSite.com Addict
    Messages: 1,239

    pump

    picture's might be tough to come up with ,they are typically on single and double Axel truck.s .scope out a city lot if you can ,they use ax drive shaft that bolts the the harmonic balancer with a slip yoke an the pump bolted to the big bumper or heavy mount .(expensive}set up.were i used to work about 15 years ago they used to install them for the local city government to control the plow ,dump,spreader ,belly blade ,ect . payup
     
  5. DGODGR

    DGODGR Senior Member
    from s/w co
    Messages: 639

    I'm not 100% sure about this but here's what I think. Most newer tractors use load sensing hydraulics. It is a complex system that incorporates a signal to the pump so that the pump can adjust it's output to meet demand. The pump itself is what is called an axial piston pump. It uses a swash plate to control how many pistons are used at one time (thus controlling hydraulic output). I have not looked closely at bumper mounted trucks to see if they have the plumbing it takes for this type of system. I think that the vast majority of these units (typically cement mixers and municipal trucks) incorporate a conventional hydraulic pump. This type of system is much less expensive and less complicated. The pump is always pumping at 100% for the RPM being employed at any given time. That is to say that more throttle = more flow (up to the maximum possible output of the pump). Whenever the demand of the system is less than the pump's output the "excess" hydraulic fluid goes through a by pass valve (that is set to the systems maximum desired pressure) and returns to the hydraulic reservoir.
    I hope that helps.
     
  6. adksnowo

    adksnowo Senior Member
    Messages: 370

    I have dealt with a F-700 bucket truck that used a belt driven hydro pump. Had triple belts running it off the crank. Smaller trucks can run a belt driven pump with a clutch pump. Bigger trucks can run a pto pump off the tranny of course.
     
  7. Greeneverywhere

    Greeneverywhere Member
    Messages: 33

    Here is our setup.

    IMG_1206.jpg
     
  8. Greeneverywhere

    Greeneverywhere Member
    Messages: 33

    Another view.

    IMG_1207.jpg
     
  9. Greeneverywhere

    Greeneverywhere Member
    Messages: 33

    I don't think it is a load sensing pump, but was plenty expensive.