"Summary of Wheel Chair Lockdown System"
Jason Zahrt Summary of Wheel Chair Lockdown System The project that I chose to work on is the Wheelchair Lock-down system. The wheelchair lock-down system is an upgrade to the current accepted method of restraining wheelchairs in moving vehicles. The current system uses four tie-downs to hold the wheelchair in place. This system is awkward, and most of the time, impossible for the person in the wheelchair to hook up themselves. These systems, even when available, are often not used, putting all persons in the vehicle in danger. The wheelchair lock-down system is an all-mechanical device, designed to be easy for the person in the wheelchair to use. It is also not a very complex device, keeping the total cost down. The person in the wheelchair drives onto the device, and stops their rear wheels on two parallel shafts. These shafts hold the wheelchair, and the wheels are free to spin in one direction. The reason the wheels can only move in one direction is that the clamp that eventually holds the wheelchair down is at its bottom limit, restricting the shafts to only turn in one direction. The shafts are fitted with a bevel gear system connected to a bi-directional screw. As the wheels turn the shafts, the screw turns, two arms raise, to which there are hooks attached to the arms. Once the wheels power the arms up toward a bar mounted to the wheelchair, the hooks attached to the arms hits against the bar, and the upward motion causes the hooks to close. Once the hooks are fully closed, they lock and hold the wheelchair in place. To disengage the system, it was proposed that a cable be pulled to remove the locking pin. The prior group didn’t discuss these ideas in detail however. Once the wheels power the arms in the fully retracted position, the shafts will stop turning, and allow the wheelchair to drive off the device.