Comb drives are a type of actuators that can be used to manage the creation and flow of electrostatic forces that are generated between a set of devices known as combs. The proper alignment of the combs in the drive help to generate this energy that in turn can be used in a number of manufacturing applications. The name for the drive comes from the fact that the components used to structure a comb drive bear a strong resemblance to the pocket combs that are sometimes used to quickly remove tangles from hair.
In actual function, the two combs that are part of the comb drive never actually touch. The energy force is generated by controlling the movement between the two combs, carefully monitoring how closely they come to actual contact. The amount of force that is generated is influenced by how closely the teeth of the combs are situated. Closer proximity of the combs results in greater force being generated, while more space between the teeth of the two combs will result in lesser electrostatic force. Depending on the intended function, the teeth may even be positioned so they are almost interlocking or have a considerable amount of space between them.
One the characteristics of a comb drive is that one of the combs will remain in place, or static, while the other will be in motion. While the two combs never actually touch, the teeth may come in close proximity to one another, with the teeth of the moving comb sliding in between the teeth of the static comb. Should the alignment not be proper and the teeth of the two combs touch, this would effectively kill any voltage difference that exists between the two combs. The general idea is that as the combs in the comb drive pass one another, they exchange places in the cycle, allowing the forces to be controlled with relative ease.
A comb drive can be found in a number of motors that are used to drive the function of heavy machinery and equipment. The drives are commonly part of the design for production machinery found in manufacturing plants as well as in other types of motors used marine and seagoing applications and power plants. While somewhat simplistic in design, a comb drive in conjunction with other components can help make the operation of these machines more efficient, which in turn helps to improve production.
By Malcolm Tatum