The rear of the robot is lifted off the ground by a large rack-and-pinion mechanism that acts as a jack.

A rack gear is a long-toothed bar; think of it as a gear that has been unraveled with its teeth rolled out in a flat, straight line. The input of a rack-and-pinion system is a rotary (spinning) motion, which rotates the circular pinion gear. The pinion gear interfaces with the rack gear and causes the rack gear to slide in a straight line; the motor's torque has been converted to a linear motion. This linear motion lifts up the rear of the Omnilander. When the motor turns, the rack extends downward and pushes the rear of the robot off the ground.

At the bottom end of the rack is a sled with two small wheels; when the Omnilander lifts itself off the ground, the sled allows the robot to slide forward as the front hook pulls it forward towards the box:

Although the rack-and-pinion mechanism is the staple of the jack system, there are a few other important components that allow the system to work smoothly. Before the motor's torque reaches the rack-and-pinion, it is redirected through a 90-degree gear connection, which has some mechanical reduction. The torque is then sent through a second set of gears, which reduces the rotation further. The total gear ratio before reaching the rack-and-pinion is 5:1. That means the motor must spin five full times to rotate the pinion gear once.

Although that may seem like a lot of reduction, it is still quite a bit less than the reduction provided by the worm gear on the front of the robot. This means that the rack gear reaches its mechanical limit sooner than the worm gear. This is a problem, because the entire climbing mechanism is connected by one drive shaft; when the rack gear reaches its mechanical limit, it will seize up the entire mechanism and prevent the robot from completing its climb. To solve this issue, one of the aforementioned gears in the rear-jack mechanism is replaced with a clutch gear; note the large, white gear in the gear train at the back of the robot.

The clutch gear introduces just the right amount of slip into the system: it grips and transfers power to the rack until it reaches its mechanical limit. At that point, the clutch gear begins to slip, which allows the front hook to keep moving while keeping the jack stationary. The clutch gear prevents the entire mechanism from locking up.

When the front hook and rear jack work together, the result is a smooth, cohesive climbing action. The climbing mechanism as a whole is fairly complex with a lot of moving parts. However, the complexity pays off because the mechanism automatically coordinates all of the motions necessary for a successful climb. Therefore, we can consider the hardware to be smart!