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  • tipped over

    Got my new Crossfire T7A--very nice chair and my first ultralight.

    Made a few adjustments for the sake of back comfort (the chair was a new in the box demo model)--First, decreased the dump by 1" (19 fsh, 16.5 rsh). I liked that, not tippy, but the seat back angle seemed too tight. So, I opened the back angle to 91 degrees (relative to seat rail--4 more than what it was). Left the COG at +2.0. Got in, leaned back, launched myself forward and promptly flipped over backward bouncing my head off the hardwood floor. OUCH! Embarrassing! And hard work to get off the floor.

    Kept the changes but now pay attention to making sure my butt is all the way back against the seat back and I'm sitting up straight or leaning a bit forward when I begin to propel myself. That seems comfortable and to work just fine. If need be, I'll close the seat back angle to where it was before.

    Double OUCH.

    I have primary progressive MS with POTS--generalized weakness and postural problems that limits me to transfers and a few steps.
    I don't have an SCI--I have generalized weakness (PPMS) with POTS and gait problems.

  • #2
    Really "cool!" You learn that flip awfully quick. After few cracks on head, brain begins to work. I did similar and made sure my head not backward. Was flip instantaneous or slow-motion?

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    • #3
      Originally posted by rlmtrhmiles View Post
      Really "cool!" You learn that flip awfully quick. After few cracks on head, brain begins to work. I did similar and made sure my head not backward. Was flip instantaneous or slow-motion?
      I think I went over quickly but it seemed like slow motion. I knew I had lost it, couldn't believe what was happening, nothing I could do but hold on and go over. Weird experience. Glad to know I'm not alone!
      I don't have an SCI--I have generalized weakness (PPMS) with POTS and gait problems.

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      • #4
        Mine always seem slow-motion. Seems I push something to the limit very slowly and once I cross thwe limit, I am in trouble same speed.

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        • #5
          When you go over a threshold, make a habit of touching chin to chest.Endos hurt but concussions hurt worse. My skull lost in a close encounter w/ a concrete porch.
          Blog:
          Does This Wheelchair Make My Ass Look Fat?

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          • #6
            Originally posted by betheny View Post
            When you go over a threshold, make a habit of touching chin to chest.Endos hurt but concussions hurt worse. My skull lost in a close encounter w/ a concrete porch.
            Thanks for the advice--I'll do the chin touch whenever I bump over anything and limit what I bump over to small stuff. An endo on concrete must have had you seeing stars.
            I don't have an SCI--I have generalized weakness (PPMS) with POTS and gait problems.

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            • #7
              "OUCH" tauble. i did the same thing a couple of weeks ago. i think our skulls grow thicker after sci, lol. i've busted mine about 4 times, on concrete. hurt like hell but never any blood.

              i never think about it and i'm sure nobody else would either. in rehab they tried to teach us if we felt ourselves going over backwards to put your hand behind your head real quick.

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              • #8
                Note tippy chair has less moment of inertia so it does not want to go straight. This can be a problem if pavement falls to the side. You should also have enough dump to ensure seat is at right angle with respect to backrest rather than a wrong angle. If you are not stuck in and slide forwards then you stack. Falls are bad. Also shear force is very bad for skin with out proper sensation. I have not so tippy chair, but can still turn on the spot. Para for now, but some wories with neck or brain.
                http://zagam.net/

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                • #9
                  If I fail to pop a wheelie in my not so tippy chair at kerb then face plant. This is usually when concerned onlookers try to help me cross the road or I am very drunk.
                  http://zagam.net/

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                  • #10
                    Hard to having enough wits about me to get my hand behind my head as I'm going over. My seat back angle may be a bit wide. The seat rail angle for my chair (16x17, 19 fsh, 16.5 rsh) is tipped up 8 degrees from horizontal. With a seat back angle of 91 degrees measured from the seat rail, that's a total angle measured from the floor of 99 degrees. Comfortable when sitting around, maybe too tippy for me when moving (6 ft, 150 lbs).
                    I don't have an SCI--I have generalized weakness (PPMS) with POTS and gait problems.

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                    • #11
                      Simple mechanical problem with vectors

                      Originally posted by tauble View Post
                      With a seat back angle of 91 degrees measured from the seat rail
                      If its not a right angle then its a wrong angle. It actually may need to be less than 90 degrees. Consider an articulated spine (no rods or cables) and hip joint. (I can prepare my hypothetical details of Ms Teflon in glorious FORTRAN comment card ASCII art.) What does gravity do if this angle is greater than 90 degrees? With friction (shear force and decubitis) and without (wooden beaded cover as used by taxi drivers)? You slide out! You also need about 10 degrees dump so you fall back in which you have.
                      http://zagam.net/

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                      • #12
                        Whenever I have tipped or fallen, my hands seems to go "automatically" to floor/gound. I guess as a way to reduce what is going to happen. I do have very strong upper body and have already fallen with hands on floor/ground and rear end still in chair.

                        Originally posted by betheny View Post
                        When you go over a threshold, make a habit of touching chin to chest.Endos hurt but concussions hurt worse. My skull lost in a close encounter w/ a concrete porch.

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                        • #13
                          to Zagam--my chair has a 2.5" dump on a 17" deep seat which results in an 8.5 degree seat to floor angle. I'd have to increase the dump to 3" for a 10 degree angle. Hmmm--I would definitely decrease the back angle if I increased the dump. For now, I think I'll keep the smaller dump while making sure my butt is all the way back and adding chin tucks over bumps. I find I'm sliding out, I'll take your advice and increase the dump.

                          to rlmthrmiles--I imagine I'll assume the hands out/butt in seat position one of these days.
                          I don't have an SCI--I have generalized weakness (PPMS) with POTS and gait problems.

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                          • #14
                            Dump should be at least 10 to 15 degrees even though 20 degrees may be ideal. The lumbar support forms an acute angle (less than 90 degrees). If you not stable and tend to slide forward then you have shear force acting on you but and may end up with decubitis ulcers, DVT, etc. Do your feet swell, get AD? Shear force is a killer.

                            I remember a good basket ball chair where I stuck like glue without strap. Knees were high so it could turn quick. As an every day chair getting though door ways and tolerating grade to side was a problem.

                            http://journals.lww.com/jnpt/Fulltex...rt_Are.70.aspx

                            Interventions were adjustment of seat incline angle to 10-15 degrees and placement of lumbar support to achieve slight anterior pelvic tilt, thus restoring lumbar lordosis.
                            While improved stability can be achieved at twenty degrees of seat inclination, one must be cognizant of the patient's ability to transfer.
                            http://zagam.net/

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                            • #15
                              I think it's rather difficult to really know what seat angle you have because it's not only about frame geometry but also about the cushion. I have 8 degrees frame seat angle but I have a Jay deep contour cushion with higher density at front and I guess it must add few degrees.
                              My TR3

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