Clamp-On Power; Easier Pushing

By Mark E. Smith, New Mobility Magazine, June 2012

The NuDrive Evo uses a lever-drive system to make wheelchair propulsion 40 percent more efficient.

The NuDrive Evo

When we look at the current demographics of ultralight manual wheelchair users, make no mistake, a significant percentage of us belong to an aging population. Those of us who came of age self-propelling beginning in the 1970s, with wheelchair sports exploding in the 1980s, have now been pushing our way through life for over 30 years — and it’s catching up with us. While manual wheelchairs became easier to propel based on advances in frame and wheel technologies, the ergonomics never really changed. As a result, shoulder, elbow, and wrist damage isn’t uncommon from decades of wear and tear on users’ bodies from moving through life one push at a time. What’s more, while damage from joint overuse in many wheelers has already occurred, there’s an increasing clinical focus on preventing such injuries in younger wheelers.

Fortunately, several companies are striving to preserve manual wheelchair use while making it, well, less manual.

Spinergy, known for its extremely popular ultralight wheels, is introducing its ZX1 “power add-on” that turns a rigid manual wheelchair into a joystick-driven power chair in seconds. At the heart of the ZX1 is a totally self-contained power base — a virtual power chair without a seat. The user backs his or her manual wheelchair over it, and with the press of a joystick button, the ZX1 automatically clamps itself to the wheelchair’s camber tube. Armrests attached to the ZX1 wrap around the user, complete with joystick, and off he or she goes.

The ZX1 features two power chair motors and drive wheels, all tucked beneath the manual wheelchair. Two 12Ah batteries and 70A electronics allow a 4-mph top speed and a 5-mile range. The power base allows the modified wheelchair to climb up to a 2-inch obstacle. At 75 pounds, the ZX1 power base is easier to transport than a power chair, fitting in most trunks. What’s most striking, though, is that when the user is finished using the ZX1, the power add-on is released at the touch of a button, returning to a full manual wheelchair in seconds.

At press time, Spinergy was finalizing FDA approval and funding coding on the ZX1, expecting to launch in the arena of other funded power-assist systems.

Enhanced Propulsion

While not an electrically powered system, the NuDrive Evo uses body ergonomics to make wheelchair propulsion 40 percent more efficient. It utilizes a lever-drive system that is both effective and practical, keeping one’s hands off of the wheels, and on ergonomic levers, rowing the wheelchair, more or less, instead of “pushing” it.

The NuDrive Evo is unique in that its levers are quick-release. First, an ultralight bracket is fitted to the wheel. Then the whole lever assembly pops on and off in seconds, allowing one to switch between lever-drive and standard push propulsion. With the levers on, a ratcheting push motion propels the wheelchair forward, whereas pulling a lever inward both brakes and steers the wheelchair. Again, requiring 40 percent less force, the NuDrive Evo not only makes propulsion easier, but more ergonomic, reducing joint stress and impact. The NuDrive Evo costs dramatically less than power-assist systems at just $1,100.

Arguably the “original” lever-drive system, the Wijit, is designed for both outdoor and indoor use. Its function is similar to other lever drives, offering 50 percent more efficient propulsion over push strokes, but it instantaneously allows conversion to a standard push mode by simply folding the levers rearward and using the attached handrims on the special wheel assemblies to propel as a normal wheelchair. In other words, there’s nothing to remove. Of course, forward, reverse, neutral, and braking are all functions of the Wijit. As a fully-integrated system, the Wijit is coded as a funded item by most insurers, including the VA.

For those seeking exceptional outdoor performance in a manual wheelchair lever-drive system, Rio Mobility combines everyday propulsion with exceptional performance in its Pivot system. The Pivot replaces the rear wheels on a manual wheelchair with gear-driven wheels and “rowing arms.” With five speeds and a push-pull motion, the Pivot allows for strikingly efficient, high-speed propulsion outdoors, where a lot of ground can be covered. It can even climb hills. Of course, braking and steering are built-in, as is forward, neutral, and reverse. To revert to normal propulsion, the Pivot wheels are removed and replaced with standard wheels.

At $3,995, the Pivot is costly. Yet, no other lever-drive system compares to its high-speed performance.

Indeed, there are now many ways to propel a manual wheelchair, efficiently, ergonomically — all with a little pizazz mixed in.

• NuDrive,; 813/514-9586
• Rio Mobility,; 415/278-9662
• Spinergy,; 866/517-4501
• Wijit,; 800/659-4548

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