It was in 2010 that we first heard about a set of ergonomic wheelchair wheels that let users move their chairs forward by pulling back on the handrims – ordinarily, of course, they would push forward on the rims. Six years later, the technology has moved from prototype to product, with the Rowheels REV-LX wheelset hitting the market just last week.
First of all, you may ask, what's the point?
Well, switching to the rowing motion reportedly recruits larger, more capable muscles in the user's upper back and shoulders. This reduces the risk of shoulder injury, and also offers a mechanical advantage – according to the Rowheels company, approximately 25 percent less force is required to propel the chair.
The wheels are available in a variety of sizes, and are installed on existing third-party chairs. Their unique propulsion system is made possible via a planetary gear system at the center of each wheel, which reverses the pulling motion of the user into forward motion of the wheelchair. Braking is accomplished simply by pressing in on the handrims.
Rowheels actually released its first production wheelset, the REV-HX, last September. The big difference with the newer REV-LX is that it's geared lower, making the wheels easier to turn. Pricing starts at around US$2,100, although a company rep informs us that buyers may be eligible from reimbursement via Medicare, their insurance company, or Veterans Affairs.
People on a tighter budget might want to wait for the lower-priced REV-3, which is still in development. In the meantime, the HX and LX can be seen in action in the video below.
For a couple of other approaches to rowable wheelchairs, check out the Freedom Chair and the RoChair.
Source: Rowheels
To try to visualize what I'm talking about watch the users hand as they push. It's operating in an elliptical movement as the most efficient way to achieve the motion, but the users hands are not in contact with the wheel for half of the motion, which leaves room for more force and better control if the empty half could be reconnected. Establish an elliptical crank with an ergonomic hand grip and the user no longer wastes half a revolution and is in control of the wheel at all times.