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Torque-RequiredStair-Climbing Device

  1. Jun 13, 2009 #1
    I am trying to figure out how to design a stair-climbing device similar to a hand-cart that climbs stairs.

    I know that the loading will be ~500 lb.

    It uses a 3-wheel climbing design design like http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200381541_200381541" except motorized.

    I am trying to figure out how much torque I will need at the output of the gear box. I am assuming that this is simply a function of the distance from the climbing-wheel to the loading.

    I also would like to figure out what size motor would work in that it should be relatively small and run off of a reasonably small portable power source.

    I have no real design experience, so I was hoping for some input/advice.

    What kind of small portable motors are out there and where can I see their specs?

    What kind of power sources are out there?

    If my questions are not that clear, let me know and I will try to elaborate.


    EDIT to help put this into better perspective, the motor is to power a 3-wheeled design like the one shown above, but it is to be used on an Ambulance Gurney (stretcher) to assist in moving 'larger' people up and down stairs.
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Jun 13, 2009 #2
    Anyone know of any good sites for motors of this sort? Google is ok, but I would like some recommended sites.

    Searching "motors" is a little painstaking.

    EDIT: Ok, I am http://www.baldor.com/products/product.asp?1=1&page=1&orderBy=HpDecimal&product=DC+Motors&family=General+Purpose|vw_DCMotors_GeneralPurpose" [Broken] right now.

    Can someone explain what armature vs field voltage? Do I need to consider these?

    I googled around and found that armature voltage is the occurs on the coils, but I am not sure why I need to know this :redface:
    Last edited by a moderator: May 4, 2017
  4. Jun 14, 2009 #3
    Any thoughts on motors/power sources? I am looking at something like http://www.baldor.com/products/deta...l+Purpose|vw_DCMotors_GeneralPurpose&hp=2.00", but I am not sure if there is a lightweight portable rechargeable power source to go with.

    I figured that the torque I need to deliver is ~4000 lb-in

    Can I go with a smaller motor without getting to crazy with the gear box? Is 2 HP at 2500 rpm considered a "big" motor.

    I know this is a broad question that is design particular, but I am in need of some help/advice as a strarting point/

    Last edited by a moderator: Apr 24, 2017
  5. Jun 15, 2009 #4


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    You'll be able to find a motor that fits your specifications on www.globalspec.com.

    As for size of the motor and how much power will be required, I would look into how high you're looking to lift the patient/gurney. By doing this, you can calculate the required potential energy change which can give you an idea on battery sizing.

    Also I have to ask- why the heck would you want to carry a patient up stairs on a gurney? What about elevators?
    Last edited: Jun 15, 2009
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