A rack lift is a type of elevator system that allows people or goods to be transported from a ground floor to higher elevations using a rack and pinion system. The size of the rack lift can vary significantly according to its intended purpose; some lifts tend to be quite large and are capable of moving both goods and people at the same time, while others are fairly small and useful only for transporting a small amount of goods from one location to another. These elevators are often used at construction sites, particularly at the sites of large structures.
The rack and pinion system includes a straight gear known as a rack; this gear will run the length of the lift system and will act as a track for the rack lift. The pinion is a round gear that meshes with the teeth on the rack gear. The rack lift car is likely to have more than one pinion gear, running along the same rack or separate racks. The rotational force of the round pinion gear is transferred to the straight force of the rack, allowing the rack lift car to move up and down accordingly. Some lifts can move horizontally in the same way as well.
Larger rack lift systems are likely to be motorized, while smaller ones may either be motorized or operated using a hand crank. Motorized units will feature a spindle or axle that connects to the pinion gear, thus rotating the gear when necessary. Controls built into the unit allow a user to change the rotational direction of the pinion, thereby changing the direction of movement of the rack lift itself. Manual versions of rack lifts will feature a hand crank to move the pulleys instead. In some cases, the hand crank may not be directly attached to the pinion at all, but may instead be fixed to an accessible point at the bottom of the lift and connected to the pinion using cables or belts.
These types of lifts are generally inexpensive to construct, and they are reliable and durable. They do tend, however, to be somewhat noisy and quite slow. Cable lifts are faster and quieter, but more difficult to construct, so they are not useful for construction sites. Hydraulic lifts are also very reliable, quiet, and strong, but are not feasible for construction sites.