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Improving ground clearance in a power wheelchair

JJV4633

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Steve, great comments (in other thread https://www.alsforums.com/forum/general-discussion-about-als-mnd/43994-navigating-power-wheelchair.html) . I have not been on this site for quite a while and I saw this post and wanted to ask you another question since you are my power chair guru. I was talking with my wheelchair dealer today, Numotion about some adjustments to my chair. fyi I have a Permobil model F3 that is about two years old. It is equipped with seat height tilt back AND foot pedal options. I use an easy lock system to secure me into the passenger side of my wheelchair van. That works fine although it reduces my ground clearance substantially so much so that I have trouble even with thresholds on doorways. When I mentioned this to my Numotion tech he indicated that the older models of Permobil's, specifically the M3 had an option for a retractable pin. This option is no longer being manufactured by Permobil. In talking with the tech support people at Permobil, they indicated that the device that was put on the M3's could also work on the F3's if I could find one.

That's why I'm writing to you and to the readers of this forum. Do you have any suggestions as to where I might look for this part and/or are there any third party sources that make such a device (retractable pin) that could be adapted to my chair.

Thanks in advance for your help
 
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lgelb

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Re: Navigating in a Power Wheelchair

I am fuzzy on what this pin does? Are you talking about a retractable controller? You mention foot clearance but you raise those after exiting the van, right?

Several used Permobil dealers on line, if you Google, also sell parts and accessories. And there is eBay. Did Permobil tech support check with their warehouse as well?
 

KarenNWendyn

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Re: Navigating in a Power Wheelchair

I have a q’straint system in my van. The corresponding bracket that had to be installed beneath my Permobil F5 has the same problem with reduced ground clearance. The mobility company that installed it made the bolt as short as they possibly could. It still scraped up the threshold of my front door, so I had to replace that with a flatter threshold. Raising the seat height or foot pedals doesn’t matter.

By contrast, my backup wheelchair is a Quantum midwheel drive, and it also has a bracket for the q’straint but much more ground clearance.

The mobility company explained to me it has to do with the configuration of the wheelchair. There is something about the Permobil front wheel drive chairs that have what my mobility guy termed “high centering”. I’m not sure what that means (Steve may know), but I question whether the retractable pin system from an old M3 would improve ground clearance on a front wheel drive chair.
 
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swalker

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I think what you are asking about is Permobil's Permolock, which has been discontinued for several years.

The Permolock was similar in concept to the EZ Lock and the QLK-150 (from Q'Straint). In each, there is a pin or pair of pins that protrude from the bottom of a bracket on the wheelchair. The pin(s) engage with a locking base that is permanently installed in the floor of the vehicle. When the pin(s) engage, the locking base locks around them and the wheelchair is secured.

With the Permolock, there were two, retractable pins. When the wheelchair is out and about, the pins are retracted. When the wheelchair is in the van, the pins are extended so the pins can engage with the locking base.

I have read that Magic Mobility has a similar locking system where a pin retracts. I have read of folks that have adapted that system to other wheelchairs, but it appears to be a pretty involved project to make that happen.

With EZ Lock and th QLK-150, the pin sticking out the bottom of the wheelchair is a bolt and that bolt is not retractable. Unfortunately, that reduces ground clearance substantially, perhaps to less than an inch under the bolt.

I use an EZ Lock and have two wheelchairs with EZ Lock plates and bolt.

On one, I know it is an EZ Lock plate, because I bought it new and had it installed. On that one, there is a lock nut that keeps the bolt from loosening up and falling out. It is easy (for someone else) to undo that lock nut and remove the bolt. The bolt is a 5/8 coarse thread bolt that can be purchased at many places. I found the bolt that came with my setup was longer than needed. I was able to replace that bolt with one a half inch shorter. Increasing the ground clearance from 3/4 inch to 1 1/4 inches made a very significant difference.

On rough terrain, we can remove the bolt and I have much more ground clearance. I still would not have as much ground clearance as the chair originally had, because the EZ Lock plate attached to the wheelchair reduces the clearance by almost an inch.

On the second chair, which I bought used so cannot confirm has a EZ Lock plate, the bolt is welded to the plate. Thus, I can't remove the bolt for rough terrain and can't replace the bolt with a shorter one. Bummer.

Both of those wheelchairs are Permobil C500. With those, the EZ Lock plate places the bolt close to in line with the drive wheels. So, driving my C500s with the bolt installed is a lot like driving a sports car on a four wheel drive road. I position the wheelchair so that taller obstacles will not hit the bolt, much like I would have an obstruction miss a car's differential.

I am in the process of getting a Permobil F5. The Permobil rep has told me that on the F5, the EZ Lock plate positions the locking bolt well aft of the drive wheels, meaning that it hangs up much more often. He said that the QLK-150 plate puts the bolt closer to the drive wheels, which would be far superior. I don't know if locking plates are interchangeable between the two systems.

Some folks have put a space between the vehicle floor and the locking base that is installed in the vehicle. Doing so requires installing a short bolt in the wheelchair's locking plate, giving more ground clearance.

A negative of the F5 (and I presume for the F3) is that it has less ground clearance that the C500s I currently have. I am very concerned about ground clearance on the F5 I am in the process of procuring.

Steve
 

Vincent

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Have you tried to put a threshold ramp or even just a 1" board in front of the door. It would only work at home or you could carry a board with you for hotels and the like. I've always been a fan of low tech solutions.
Vincent
 

lgelb

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Ah, the bolt on the bottom, sorry I zoned. In that case, everything I said + adaptive van dealers bc they may have parts lying around for mods. Google adaptive mobility [city name]

Permobil likely has interchangeable parts for the M/F 3/5 models (the same generation) as much as possible, but as Steve points out, the C/M 300/500 were the last gen, so a completely different system.
 

Narrowminded

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We did like Vincent with our thresholds. We got higher door mats and in some cases, tossed the mat over the threshold while Brian was coming or going over top of it. Works like a charm and inexpensive too. We also had a 1” ramp at our old home very narrow by the door for the same purpose. Remember though you need to have that mat/lift on either side of the threshold, not just one.
 

JJV4633

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Re: Navigating in a Power Wheelchair

I am fuzzy on what this pin does? Are you talking about a retractable controller? You mention foot clearance but you raise those after exiting the van, right?

Several used Permobil dealers on line, if you Google, also sell parts and accessories. And there is eBay. Did Permobil tech support check with their warehouse as well?
I currently am using an EZ lock system to secure my chair in my handicap van. The pin I am referring to is currently affixed to the bottom of my chair midway between my front wheels in my rear caster wheels. With the pin installed my ground clearance is only about 1 to 1 1/2 inches. This pin is not retractable.

Permobil used to make a retractable pin mechanism to address the low clearance issues. They discontinued that product several years ago. I have checked with Permobil tech support and since the product has been discontinued several years ago they no longer have any in stock. It was their suggestion that I checked the used market.

Your suggestion about checking with used Permobil dealers is a good one and worth following up..
 

frankb

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had the same problem with my f5. my van dealership simply shortened the bolt by cutting it as much as possible while allowing enough length to engage the ezlock. works fine now.
 
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