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New Device To Power Manual Wheelchairs

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    #16
    If this buggy is fast (and I hope it it!) deceleration is an issue!
    Nonoise kind of left this open. The machine should have a very short "coast down" or, as my ZX-1, a braking function.
    In any case, when you can go 6?mph, it is important to be able to stop quickly if you fuck up! But it's also incumbent on the engineers to support slow decel as well.

    Regarding attachment: seems to me a simple latching setup with two cutouts, U shaped with whatever radius your axle tube has would be easy to implement and easy to latch/un-latch.
    Just maneuver the latch up against your axle and pus it down to latch. A small L shaped appurtenance could be used to unlatch and lift off in one motion.
    The only possible issue being that it might slide laterally in use. This hasn't proved an issue on the ZX-1. If it was, a pair of split shaft collars could be mounted on the axle and left on.

    Here's a quick sketch. Hindsight is 20:20 (why it's best to draw stuff before making it)
    Forget the pair of hairsprings on the two latches; substitute a coaxial coil spring on the latch-pull between the cross-piece and the rod connecting the latches.
    Perhaps refine the interface of the axle tube and the latching device to ensure it doesn't unlatch under unusual loads or angles. I put the long faces in back to make it easy to find and attach to the WC axle, but the thrust face is on the shorter part; perhaps ovalize it a little so the drive-force will socket it and not load the latch-arm (actually, I think this is not at all a possible problem, I get paranoid sometimes) Certainly the axis of the "U"s must be perpendicular to a line form it to the center of the machines axles ensuring that drive/decel force exerts minimal force that tries to un-couple the thing!!

    Also, I drew it with the handle forward; the handle should be reversed to make it easier to reach and manipulate.

    PS: I designed this with a separation of the two sides with the understanding that your two wheeled system torque steers the chair (hence the 360* capability) and requires a robust base to the axle. Perhaps the base should be even wider than illustrated.
    EDITED: I thought about the 360* turning. (I don't think it works ) If you are running two motors and reversing one, spinning around IMO won't wok unless the virtual "axle" of the machine tires is directly below the WC axle. Any other geometry and it has to slide the WC tires in order to follow it's own arc; that won't happen. Sorry-I can't turn off the big letters!

    Which make me wonder. I've assumed you're running a pair of motors so you can have some steering function. Are you?
    I don't think such an arrangement would even steer larger arcs very well for the same reasons.

    PPS: not a good latch for quads! Requires the ability to squeeze the handle and latch-handle together to load it. Also, I guess, might be difficult for quads to pull up on latch release but IMO doable.
    Would be nice if the device latched itself when pushed down over the axle.
    I'm thinking
    Attached Files
    Last edited by pfcs49; 12 Jul 2019, 11:47 AM.
    69yo male T12 complete since 1995
    NW NJ

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      #17
      ???? how to delete a post?

      still not seeing how to delete a post.
      I can delete most of it but it insists oo away!n a minimum of characters and won't let all go away.
      Last edited by pfcs49; 12 Jul 2019, 7:47 PM.
      69yo male T12 complete since 1995
      NW NJ

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        #18
        Originally posted by pfcs49 View Post
        ???? how to delete a post?
        Cant. Edit it down to "......." and save it like that.
        "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

        "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

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          #19
          im suposed to be going for a smartdrive eval i wonder if i should wait till this comes out wish yall had a better video
          to alcohol the cause of-and solution to-all of lifes problems [homer simpson]

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            #20
            Phil wrote:
            "If you are running two motors and reversing one, spinning around IMO won't wok unless the virtual "axle" of the machine tires is directly below the WC axle."

            Phil is smart. I agree with what he said.
            I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

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              #21
              Originally posted by pfcs49 View Post
              ???? how to delete a post?
              Go to the lower right hand corner of your post. Hit edit.
              I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

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                #22
                Originally posted by ProPulse View Post
                @giles88 We are also still in the prototyping/testing phase so if you have any suggestions just throw them out there!
                If it's got the ability to have direct control (joystick) over propulsion, and the ability to go offroad, then you have the important things covered for me. The only other thing would be speed, it would be nice if it had the ability to go fast if the user wanted to.

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                  #23
                  @Nonoise Thank you so much for your feedback! we will address each of your concerns below.
                  1. You are correct, the phrase ?360 degree turning?is confusing. We meant zero turn radius like you mentioned. We are adding a joystick so that users can easily turn with grabbing the wheelchair rims.
                  2. We are working on different mounting techniques,including magnetic assist. The idea of magnetic assist is to ?guide? users to the right mounting spot and attach the product without much force needed.
                  3. We are building the product to be as efficient as possible to extend battery life.
                  4. With respect to steep inclines, having a second motor really helps! And a good wheel material is key to overcoming this problem. We will let you know how testing goes.
                  5. We are currently testing different connection types for the joystick, but we agree with you on hard wire, it is very dependable!
                  Thank you so much for taking the time to talk to us, we definitely pay attention and will get work on all your concerns!
                  Last edited by ProPulse; 22 Jul 2019, 10:45 PM.

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                    #24
                    @wheelin48
                    It is easily mounted with magnetic assist to guide you to the right spot, you could mount it with your eyes closed!

                    Last edited by ProPulse; 22 Jul 2019, 10:44 PM.

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                      #25
                      @oddity
                      Sorry for the late response! Thank you for making greatpoints to be considered.
                      Our idea was to make a product that reaches as many users as possible, that's why we added off-road. But you are right to say that it can't make the chair off-road! Great point ��
                      On your last point about insurance, would you consider buying a product out of pocket to skip the insurance approval process?

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                        #26
                        @pfcs49
                        Thank you so much for getting back to us, this is really great information!
                        Safety is one of our priorities, so a well-thought-out braking solution will be added to final design.
                        We love your mounting idea! It was a great drawing by the way �� We will test your idea and see how easy it is for users to mount and take off, certainly we will let you know how it goes.We do have magnets in place to guide the user for easy mounting. But we are still testing different handles easy to reach while being seated on the chair!
                        Question: Would you like to mount the attachment, prior or after seating on the chair?
                        With respect to 360: The attachment does have two motors,and they are separated by a distance that produces a moment on the WC axis when rotating at different RPMs. 360 spins are only possible from a dead stop,otherwise your statement is true! We will be posting videos showing it's capabilities, so stay tuned!
                        Thanks again for your input, it is very useful!

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                          #27
                          @giles88 How fast were you thinking? Our top speed can go extremely high but we also want to balance it with the safety of the user. 8, 10, 12 mph?

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                            #28
                            I am also pleased to say that we took everyone's advice on the last post I made, almost all of our components are off the shelf so far

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                              #29
                              As of today, top speed is 8mph. HOWEVER we just ordered some new parts that will up the power by around 35%-40%. That doesn't meant the final product will be 13mph (someone could get hurt) but the potential is there. We also just got back inside after doing some testing through extremely uneven Texas grass. Huge success! Sorry again for the delay everyone! There was a lot to think about with all of the suggestions. The entire team went through one by one and debated every one of them.

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                                #30
                                Ive paid over $12k out of pocket for bespoke wheelchairs over the past decade, so paying out of pocket doesnt bother me too much. However, we're talking about spending thousands instead of hundreds based on avoiding a trip to the doctor. Doesnt make a ton of sense to me, especially considering all we have to do is ask, the "approval process" is done by the doctor's billing/coding staff, not us. All we need to do is ask and wait. Thats worth saving thousands of dollars IMO. I only go out of pocket for items insurance wont cover.

                                I have another comment about weight. Ive been fiddling around with a SmartDrive for about a week now, and I was initially surprised by how heavy it is for its size. After using it for a bit I couldnt imagine it working well if it were lighter. The weight translates into traction. I'd consider not being too fussed about weight at the expense of too much traction.







                                Originally posted by ProPulse View Post
                                @oddity
                                Sorry for the late response! Thank you for making greatpoints to be considered.
                                Our idea was to make a product that reaches as many users as possible, that's why we added off-road. But you are right to say that it can't make the chair off-road! Great point ��
                                On your last point about insurance, would you consider buying a product out of pocket to skip the insurance approval process?
                                Last edited by Oddity; 22 Jul 2019, 11:16 PM.
                                "I have great faith in fools; self-confidence my friends call it." - Edgar Allen Poe

                                "If you only know your side of an issue, you know nothing." -John Stuart Mill, On Liberty

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