Patent ID: RE39747

Claim:
Apparatus for detecting the position of a moving element relative to a stationary element, said apparatus comprising: a plurality of linear encoder readers spaced generally along the stationary element at fixed positions relative thereto; a device readable by the linear encoder readers, the readable device being mounted on the moving element and having a length which is greater than the spacing between any given pair of adjacent linear encoder readers; a guide for aligning the readable device in order to interact with the linear encoder readers; and circuitry, connected to each linear encoder reader, for associating the readable device with only one linear encoder reader in a state of interaction with the readable device at any time and for resolving and providing a reading of the overall position of the moving element based on the fixed position of the associated linear encoder reader and a relative position of the readable device in relation to the associated linear encoder reader ; wherein, in a condition where the readable device is associated with a given linear encoder reader and simultaneously begins to interact with an adjacent linear encoder reader, the circuitry is operative to switch the association of the readable device with the given linear encoder reader to the adjacent linear encoder reader once the readable device has reached a pre - specified distance through one of the given linear encoder reader and the adjacent linear encoder reader, the circuitry being operative to initialize the adjacent linear encoder reader prior to the interaction of the readable device with the adjacent linear encoder reader .