A lift mechanism for a wheel assembly includes a lever arm having a first axis of rotation, and a first torque transfer plate having a second axis of rotation coincident with the first axis of rotation. A lift block is engageable by the first torque transfer plate and has a first angularly disposed surface and a resting surface adjacent to the first angularly disposed surface. The lift mechanism is configured such that rotation of the lever arm causes the first torque transfer plate to rotate into engagement with the lift block, thereby causing linear motion of the lift block. The wheel assembly is raised and lowered by contact between a portion of the wheel assembly and the first angularly disposed surface of the lift block and held in a raised position when the portion of the wheel assembly is positioned with respect to the resting surface.
