Can we design an A frame that all would agree is legal?

Discussion in 'Tech/Mech General' started by olley, Nov 1, 2007.

  1. olley

    olley Funster

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    Hi I haven't been involved in the discussion, but I have been thinking about ways to make certain aspects legal. One is the inability to reverse under control, one way to achieve this is for the front wheels to be lifted clear of the ground by some means.

    The actual "A" frame could be used for this if the mounting points on the car were strong enough to support the weight of the front of the car, and if your tow hitch could support a downforce of about 500kg. Then using a hydraulic ram fitted under or above the hitch with the other end connected near to the opposite end of the "A" frame, you could lift the front wheels clear of the ground turning it in to a two wheeled trailer, which can be reversed under control. The hydraulic power could be supplied locally or from the steering pump.

    Olley
     
  2. Road Runner

    Road Runner Read Only Funster

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    My A frame has a Jockey wheel fitted so if a problem does occur you can quickly unhitch the vehicle and drive it where needed using the jockey wheel.

    MHfun rally goers have seen it in action.

    I had to do this when at the tunnel when they expected me to do a tight U turn onto the train that the bus couldn't do in one go anyway:RollEyes::Doh:I should have been with the HGV's as I was longer than most of them.

    To be honest you cant see your toad properly when reversing anyway so this is your safest option :Wink:
     
    Last edited: Nov 1, 2007
  3. Jim

    Jim Ringleader

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    This thread has spent the best part of today "closed" that was a mistake, please do post here. If we can invent an A frame that everyone deems is legal well.. ££$$.....


    This time next year Rodney.....:Rofl1:
     
  4. American Dream

    American Dream Read Only Funster

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    Excellent More info available again.

    Cheers Jim.

    :thumb:
     
  5. Tony Santara

    Tony Santara Funster

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    Hi Olley
    the power to lift a car would be quite a lot i would imagine going off the effort it takes to jack up a car
    I think the better way would be to look at some device that could be fitted to steering to make that turn accordingly when reversing

    Trouble is i don't know what yet :RollEyes:
     
  6. American Dream

    American Dream Read Only Funster

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    Would be a problem with the normal power steering cars.

    No prob with rack and pinion types as far as I can see.

    The steering lock would need to be disabled though .:Rofl1:

    How many cars come without power steering now ?

    A pair of idler wheels that lower when reversing?
     
    Last edited: Nov 1, 2007
  7. Road Runner

    Road Runner Read Only Funster

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    Last edited: Nov 1, 2007
  8. Tony Santara

    Tony Santara Funster

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    Recovery only John
    Try again mate :thumb:
     
  9. Tony Santara

    Tony Santara Funster

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    good one Steve how would you power them and on what would you mount them ?
     
  10. Road Runner

    Road Runner Read Only Funster

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    You caught me there Tony I had not put down what i actually meant:RollEyes: (sorry for the edit in between:RollEyes::Blush:)

    I have had tilt/slide recovery lorries with extending spectacle frame for recovery for :Wink:

    Got nicked:Doh:
     
  11. American Dream

    American Dream Read Only Funster

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    Power via an integral Fluid pump.

    Just a thought.

    My Smart car had an electrically powered brake servo pump.Use a 12v Hydraulic Pump. Fit a large capacity Hydraulic fluid reservoir.

    Couple that to a pair of hydraulic rams to provide lift with Upper and lower extremity safety switches and appropriate warning light/reversing siren, lamp on dash and...........

    Oh Well Just a thought.:Doh:
     
    Last edited: Nov 1, 2007
  12. Road Runner

    Road Runner Read Only Funster

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    How about a robot innit steering it mimicking the bus driver?

    Suppose you'll still have to rely on the dummy to reverse though:Laughing:
     
  13. Tony Santara

    Tony Santara Funster

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    Steve
    Could they not be powered electricaly to keep it simple
    fluid reser and hyd pumps sound a bit heavey

    But hey we're thinking :thumb::thumb:
     
  14. Road Runner

    Road Runner Read Only Funster

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    The mind boggles how this is going to be safe.

    I'll stick to my braked A frame for now.
     
  15. American Dream

    American Dream Read Only Funster

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    Hi Tony.

    I did mean a 12v Hydraulic pump.

    I don't think it would be very heavy at all.

    The rams might weigh the same as a couple of motorcycle Rear Shockers.

    The mech would be integral to the frame and the additional electrical connections would be via an extra connector to the van's electrical system via fuses etc.

    eg Sealed hydraulic system.
     
    Last edited: Nov 1, 2007
  16. Tony Santara

    Tony Santara Funster

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    Got you Steve

    I was thinking along the lines of electric motor thru some kind of gearing on an arm
    trying to think along the lines of van tail lift operation

    any way i'll have to sleep on it up at 4 am for work

    BTW Olley's gone quiet is he still thinking :Laughing::Laughing:
     
  17. American Dream

    American Dream Read Only Funster

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    Braked "A" frame eh.

    Now you didn't mention that earlier.:BigGrin:
     
  18. Road Runner

    Road Runner Read Only Funster

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    No one took my robotic dummies seriously:cry:
     
  19. American Dream

    American Dream Read Only Funster

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    I will John

    Will get the missus to emulate them tomorrow.:Doh:
     
  20. olley

    olley Funster

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    If a hydraulic ram has a surface area of 1" and you have oil at 1000psi that's 1000lbs that ram can exert, enough to lift the front of a small car.
    Remember many RV's including mine have jacks capable of lifting the entire RV clear of the ground.

    You could also use a caster wheel on a leg, again hydraulically powered to lift the front clear, if the pivot was the same as the "A" frame mounting points on the car then no strengthening mods would be needed on the towing car.

    Either of these or other ideas could be energised by a relay powered from the reversing light.

    This is only going to be used when reversing so safety shouldn't be an issue.

    Olley
     
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