LiftWalker uses ball-scew actuator to help patients leave wheelchairs

The new LiftWalker from medical manufacturer Ideomotion is a stainless-steel frame with 12 V actuators that run off two rechargeable Nickel-Metal-Hydride batteries. Made in the U.S., the walker assists people from 3 ft 6 in. to 6 ft 6 in. tall and up to 300 lb with juvenile, preschool, and X large models. An easy-adjust thoracic prompt fits to the user in moments and comfortably lifts them to standing in a few seconds.

Thigh prompts make standing possible for almost anyone. Patients use their biceps, chest, back, stomach, and leg muscles simultaneously to engage the frame, increasing strength. This is safer than being pulled by an attendant or caregiver.
The New LiftWalker uses Motion Systems Corp. Model 85199 ball screw actuators to pull the patient up from sitting.

A ball cage within the nut ID cams up against stop pins at each end of travel to initiate freewheeling and linear advancement stops. The stop pins are mounted in the screw thread and are factory installed for the specified stroke. This design generally eliminates the need for externally mounted limit switches. Motor speed reduction to drive the Ball Screw is by a single stage worm gear reducer. The housing is die cast aluminum alloy. A molded neoprene coupling with steel inserts couples the motor shaft to the worm shaft and provides protection against shock loads. The worm shaft runs in an oilite bearing at the motor end and a ball bearing at the opposite end. The Ball Drive is mounted in a ball bearing at the output side of the gear reducer which takes axial thrust loads, and an oilite bearing at the opposite end. Both the worm and gear are heat treated steel for long wear life. An aluminum cover tube with a quad ring seal at its outboard end encloses the screw.

“The ball drive actuator has sufficient advancement speeds and custom stroke,” said Erik Wolf, president, Motion Systems Corporation. “With the Ideomotion walker, the actuator provides the mechanical muscle to help a wheelchair-bound person stand up and walk.”

Motion Systems Corporation