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The Wheelie Scale: A DIY-AT Open-Source Innovation – Erik Kondo

Updated: Feb 3, 2023


I surveyed about fifty manual wheelchair users and discovered that about ninety percent of them weighed themselves a few times a year or less. Most people only weighed themselves at a doctor’s office or medical facility. Other weighing methods were to have someone pick them up and stand on a scale, or to use the animal scale at a veterinarian’s office. Ninety percent surveyed would like to be able to weigh themselves at home either once in a while or regularly.

Search the phrase “bathroom scale” on Amazon and you will find a huge selection of choices of portable stylish scales in the $20-$40 range. Search for wheelchair scale” and you will find a few industrial looking and bulky devices for several hundred dollars to a few thousand dollars for sale. As a consequence of the lack of affordable and portable options, most wheelchair users don’t keep track of their weight despite wanting to do so.

The ability to keep track of your weight is an important tool for maintaining your health. Being able to determine sudden weight gain or weigh loss helps you to identify the onset of potential health problems. Despite the fact that the benefits of regular weighing have been well established, few options exist for manual wheelchair users. Thus, the need for the Wheelie Scale.

The Wheelie Scale[1] is an mechanical adaptation that allows a manual wheelchair user who is capable of maintaining the wheelie position[2] to weigh themselves using many of the models of inexpensive bathroom scales currently available. It is based on the concept of using the small linear footprint created by a wheelchair in the wheelie position. It allows manual wheelchair users to “step” (roll backwards) on the scale. The Wheelie Scale holds the wheelchair’s rear wheels in position in order to enable the wheelie position[3]. The weight registered on the scale is the total weight of the person and his/her wheelchair. Therefore, the empty wheelchair will need to be weighed prior and its weight subtracted from the total.

There are many ways in which a Wheelie Scale can be created. The photos show two versions, one that uses wood and glue, the other that uses metal and welding. Another method could use square rather than round tubing and bolts instead of welding, or maybe something else entirely different. Regardless of the exact manufacturing method, the concept remains the same – take advantage of the capability of a person to “stand” in a wheelie in order to adapt to current consumer products.


Notes:

[1] The Wheelie Scale concept and prototypes were developed by Erik Kondo and Arthur Torrey.

[2] There will be some that will say “But not every wheelchair user can get into a wheelie position”. Their point is that an innovation should be able to work for all wheelchair users in order to be useful. My response is: "Not everyone can stand on a scale either". Therefore, should we get rid of all standing scales since not everyone can use them? No, of course not. Why should all the people who can stand on an inexpensive bathroom scale be forced to use an expensive and unsightly “universal” scale for the sake of fairness? It doesn’t seem to be a problem in society that standing people can use scales that wheelchair users can’t. Therefore, why wouldn’t the same logic apply to the population of wheelchair users?

That being said, my hope is that future innovations will create scales that are inexpensive and can be used in the non-wheelie position. Innovation is a step-by-step process. One improvement leads to another. Hence the need for Open-Source Innovations as opposed to protected and restricted intellectual property.

[3] It is possible to use the Wheelie Scale in the non-wheelie position by mathematically calculating the percentage weight recorded by the rear wheels in order to obtain a weight estimation. This method will require the wheelchair user to know his/her exact weight when making the calculations along with having basic math skills.


Constructed with wood and glue.


Constructed with metal and tack welds.




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