When a standard joystick isn't enough: the Heavy Duty Joystick
by Guest Blogger Michelle L. Lange, OTR/L, ABDA, ATP/SMS
The most common means of driving a power wheelchair is a joystick. A joystick is a proportional driving method which provides full directional control in 360 degrees as well as speed control. The farther the driver moves the joystick from center, the faster the power wheelchair will go.
A standard joystick requires about 250 grams of force to move and sustain the handle away from center. The distance or throw the joystick must be moved from center to achieve full programmed speed is 20 mm.
The Problem - ability to sustain excessive forces
Some wheelchair users exert significant forces against the joystick handle. This can lead to damage within the joystick housing itself and result in the joystick no longer working.
Heavy Duty Joysticks are designed to withstand more force with reduced chance or breakage. Clients with increased muscle tone and/or movement disorders such as dystonia are more likely to use excessive force against a joystick.
When this much force is exerted, control is often compromised. Many people using enough force to break a standard joystick will not have adequate motor control to successfully use any type of the joystick and other driving methods should be explored.
The Solution - Heavy Duty Joysticks
Early Heavy Duty Joysticks were digital (non-proportional) and, as a result, did not provide full directional and speed control. Instead, only 4 or 8 discreet directions were available: Forward, Left, Right and Reverse in the 4 direction configuration with the addition of diagonal control on the 8 direction configuration. Speed was also not proportional but set at one speed only.
mo-vis offers the Heavy Duty Joystick. It is available as a stand-alone joystick or as a kit which can be retrofitted to a standard joystick module (Q-Logic or R-net) and is designed to withstand forces up to 650 grams, 2.5 times more than a standard joystick.
This joystick also accommodates a larger throw of 40 mm or the double of a standard joystick.
In addition to accommodating increased force to minimize risk of damage, this joystick remains proportional - the driver retains full directional and speed control.
The joystick handle of the Heavy Duty Joystick is also non-removable. Drivers who use excessive force are more likely to inadvertently pull off the joystick handle. People who would benefit from this option often will have trouble using the buttons and dials on the joystick itself.
To accommodate this, the Heavy Duty Joystick incorporates 2 switch jacks, one for wheelchair Power and one for Mode. Any switches can be connected to provide this control for the driver. Mode is used to change the mode of operation of the power wheelchair from driving modes to other modes including power seating which can then be controlled through the joystick itself.
Finally, like all mo-vis products, the Heavy Duty Joystick incorporates a mini USB port to allow for programming above and beyond the power wheelchair electronics using the mo-vis Configurator Software.
Learn more about the Heavy Duty Joystick