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Thread: Help me make a lighter arm rest for Permobil F3

  1. #1
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    Help me make a lighter arm rest for Permobil F3

    Anyone got any ideas? Even with the compact joystick it's still too heavy to lift up for transfers. I have the swing away attachment, instead of the heavier retractable joystick.

    Are there any after market arm rests that will fit on the new F3 seating system?

    Thanks!

  2. #2
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    First check that arm rest pivot allows smooth, no drag resistance movement. Some are designed with a little drag. Mine can be raised half way and stay there until pushed down. This is designed drag/friction. Removing a washer and/or adding one of a certain size and thickness in the correct location should help.
    Also check arm rest is not dragging on seat back cushion when raising arm rest.
    If neither of these help, it's fabrication time. Maybe a wound (not coil) spring can be installed around pivot and would lighten the load. Finding the correct spring and correct strength spring will be trial and error.

  3. #3
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    Excellent ideas Gearhead, however I have the arm rest friction mostly where I like it (tiny bit of friction), and there's no drag on the seat back cushion. Currently I have a bungee cord rigged up between the end of the arm rest and top of the back/head rest to add tension and assist getting the arm up. It's not ideal. . .I don't want to lose an eye when that cord breaks and the hooks go flying!

    I wonder if a trough armrest might be lighter weight? Don't need the trough feature, but I remember reading somewhere that the trough armrest adapter allows you to install after market arm rests. It would be great to find an arm rest that has the same "waterfall" sides as I'm used to on my old Permobil Chairman Entra. My dealer insists after market arm rests can't be put on the F3.

  4. #4
    Quote Originally Posted by beatscookin View Post
    Excellent ideas Gearhead, however I have the arm rest friction mostly where I like it (tiny bit of friction), and there's no drag on the seat back cushion. Currently I have a bungee cord rigged up between the end of the arm rest and top of the back/head rest to add tension and assist getting the arm up. It's not ideal. . .I don't want to lose an eye when that cord breaks and the hooks go flying!

    I wonder if a trough armrest might be lighter weight? Don't need the trough feature, but I remember reading somewhere that the trough armrest adapter allows you to install after market arm rests. It would be great to find an arm rest that has the same "waterfall" sides as I'm used to on my old Permobil Chairman Entra. My dealer insists after market arm rests can't be put on the F3.
    I'm not sure how it would be possible to make it lighter, unless you're skilled at use of an aluminium mill, or something. It's all cast iron, and it's so linked to other mechansims (e.g. the one to adjust the angle) I'm not sure how you'd get rid of a lot of weight.

    How long are your armrests? Making them longer would give you more of a lever so less force required to lift it?

  5. #5
    Your DME is not correct. While it is true that Permobil no longer carries the "waterfall" armpads they used on their discontinued "PS" seating system, they still offer the 7/8" arm trough adapters that will allow more-traditional arm pads to be used on the Corpus 3G seating system.

    Ironically, we never use them to install arm troughs, but we order them all the time to reduce the overall width of the chair. We typically order Quickie's waterfall arm pad, but the style Permobil carried are available from a number of other suppliers (it's a fairly light arm pad).

    It is important to note that only the 7/8" adapter will work with aftermarket armpads.

    That's a fairly substantial modification that's only going to save a little bit of weight. Keep in mind that they do not extend forward as far as Corpus arm pads. Additionally, mounting the compact joystick where you need it could be a challenge as far as identifying compatible parts.

    Also keep in mind that it's not just the weight, the ergonomics involved are just plain awkward. Even if everything was made out of carbon fiber, it still wouldn't be easy.

    I don't know much about your function, but it may be possible to improve your mechanical advantage by using your power recline. As your back angle increases, the armrests will angle upward. This gives them a "head start". The front of the arm pad will be higher, which may give you more leverage. Reclining reduces the total arc through which armrest must travel and shifts its center of mass up and toward the back of chair so that less effort is needed. Adding tilt could further reduce the load.

    Of course, any technique based on these principles is only going to be feasible if you have a way to restore your seating angles and turn off the power after the armrest is flipped back. (Is there an ICS Switchbox on the opposite armpad?)
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    SCI_OTR, how long are the quickie arm rests? My current ones are 14" x 4." I just need a little boost, so this might work. Where do I look for other suppliers of arm pads?

    I don't think the power recline idea will work because I need the opposite arm rest down to use to transfer back into the chair. Can you explain your idea of an "ICS Switchbox on the opposite armpad?" Would that be an added recline switch? What would it look like and how would it mount?

    Also, what's that neat looking cord wrapping around the joystick cables in your photo? And where can I get it?

  7. #7
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    Quote Originally Posted by beatscookin View Post
    SCI_OTR, Also, what's that neat looking cord wrapping around the joystick cables in your photo? And where can I get it?
    That's wiring loom dress up wrap. Can be used to contain multiple instead of using tie wraps. Most auto parts stores carry it. Available in many colors.

  8. #8
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    Ive missed these kinds of (unique to this site) informative posts.




    I wonder if the vets who come through your shop realize the kind of service they're getting? You've posted so many subtlety tuned and customized solutions, over the years, it makes me smile to know most of them are going to our vets. Cheers!


    Quote Originally Posted by SCI_OTR View Post
    Your DME is not correct. While it is true that Permobil no longer carries the "waterfall" armpads they used on their discontinued "PS" seating system, they still offer the 7/8" arm trough adapters that will allow more-traditional arm pads to be used on the Corpus 3G seating system.

    Ironically, we never use them to install arm troughs, but we order them all the time to reduce the overall width of the chair. We typically order Quickie's waterfall arm pad, but the style Permobil carried are available from a number of other suppliers (it's a fairly light arm pad).

    It is important to note that only the 7/8" adapter will work with aftermarket armpads.

    That's a fairly substantial modification that's only going to save a little bit of weight. Keep in mind that they do not extend forward as far as Corpus arm pads. Additionally, mounting the compact joystick where you need it could be a challenge as far as identifying compatible parts.

    Also keep in mind that it's not just the weight, the ergonomics involved are just plain awkward. Even if everything was made out of carbon fiber, it still wouldn't be easy.

    I don't know much about your function, but it may be possible to improve your mechanical advantage by using your power recline. As your back angle increases, the armrests will angle upward. This gives them a "head start". The front of the arm pad will be higher, which may give you more leverage. Reclining reduces the total arc through which armrest must travel and shifts its center of mass up and toward the back of chair so that less effort is needed. Adding tilt could further reduce the load.

    Of course, any technique based on these principles is only going to be feasible if you have a way to restore your seating angles and turn off the power after the armrest is flipped back. (Is there an ICS Switchbox on the opposite armpad?)
    "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

    "Even what those with the greatest reputation for knowing it all claim to understand and defend are but opinions..." -Heraclitus, Fragments

  9. #9
    I had the dealer install I believe the quickies instead of those monstrosity's Permobil uses. much nicer

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