Absolute position reference system for an elevator

A method of determining the position of an elevator car within a hoistway that includes the steps of:

• mounting a code rail strip within the hoistway that extends along the length of said hoistway,
• placing optically readable indicia upon the code rail strip for identifying vertically spaced locations along the hoistway,
• mounting an optical sensor upon the elevator car in a position for optically reading location related indicia contained upon the code rail,
• forwarding position related data from the optical reader to a car controller having a processor for carrying out various car related functions relating to the position data and placing a code rail section adjacent to said code rail strip at each car landing so that the reader can simultaneously read indicia on adjacent code rail sections.

A method of determining the position of an elevator car within a hoistway housed within a building, said hoistway having a series of vertically disposed landings, each containing a door frame, said method including the steps of:

• mounting individual vertically disposed code rail sections at each landing so that a gap is initially maintained between adjacent code rail sections,
• placing optically readable indicia markers upon each code rail section that is indicative of the car's position relative to an adjacent landing,
• mounting a first lower sensor and a second upper sensor in spaced vertical alignment on said car, the space between sensors being greater than the gap between adjacent code rail sections, and
• providing position related data from said sensor to a processor in the car controller whereby various position related functions can be carried out.

A method of determining the position of an elevator in a building housing a hoistway having a series of vertically aligned landings, each of which contains a door frame, said method including the following steps of

• mounting a continuous code rail strip vertically along the length of the hoistway adjacent to the path of travel of said car,
• placing optically readable primary indicia markers upon the strip that are indicative of the car's position within the hoistway,
• mounting discrete vertically disposed code rail sections at each landing adjacent to the continuous code rail strip,
• placing optically readable secondary indicia markers on each code rail section that are indicative of the car's positions relative to each landing.
• mounting a single sensor upon the car capable of simultaneously reading the code rail strip and the individual code rail sections as the car moves along the hoistway, and
• providing primary and secondary position data from the optical reader to a car controller whereby various car related functions can be controlled.

Apparatus for determining the position of an elevator within a hoistway that includes

• an elevator car mounted for reciprocal movement along a vertical path of travel within a hoistway,
• vertically disposed code rail sections mounted at specific locations relative to the elevator car's path of travel, each code rial section containing a series of apertures formed therein relating to an associated location, adjacent code rail sections being separated by a gap (d),
• a first read head mounted upon said car having a vertically disposed slot formed therein for receiving the code rail sections as the car moves through said specific locations,
• a second read head mounted upon said car a given vertical distance (D) above said first read head, said second read head having vertically disposed slots formed therein for receiving the code rail sections as the car moves through said specific locations,
• said vertical distance (D) being greater than the gap distance (d) such that the read heads are capable of reading two adjacent vertically disposed code rail sections, simultaneously, and
• each read head containing an array of light emitting diodes on one side of said slot and an array of light detectors on the opposite side of said slot for reading the data on said code rail sections and providing output signals to the car controller indicative of the car's position within said hoistway.