Discrete position location sensor

• US 4,362,224 A
• Filed: 09/21/1981
• Issued: 12/07/1982
• Est. Priority Date: 11/13/1977
• Status: Expired due to Term

• Current Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Original Assignee: Otis Elevator Company (Otis Worldwide Corp.)
• Inventors: Fairbrother, Robert E.
• Primary Examiner(s): Truhe, J. V.
• Assistant Examiner(s): Duncanson, Jr., W. E.
• Application Number:
  US06/304,212
• Time in Patent Office: 442 Days
• Field of Search: 187/29, 250/237 R, 250/237 G, 250/561, 250/578, 318/480, 318/640, 340/19 R, 340/21, 340/686
• US Class Current: 187/291
• CPC Class Codes: B66B 1/50 with operating or control mechanisms mounted in the car or cage or in the lift well or hoistway

Abstract

A discrete position encoder includes a plurality of detectors, arranged along a direction of motion or relative position between two objects, which are rendered responsive in either of two states by another member which is relatively movable with respect thereto, such as light beams established by light sources and optical detectors being interruptible by a vane. The vane is adjusted so that when the two objects are centrally aligned with each other, the two outermost detectors have a state opposite to other detectors. Two rows of detectors are provided to permit flexibility in designing the positional extent of detectable discrete positions. Exemplary decoding includes the decoding of as many fault states as acceptable decodable discrete position states. Embodiments with opposite detector states (ON/OFF vs OFF/ON) are disclosed.

Claims

1. A position encoder comprising a first member and at least one second member, said members being relatively movable with respect to each other, said first member having disposed thereon N detectors, each having two states, the proximity of said second member with each of said detectors causing such detector to assume a first one of two states and the absence of said second member in proximity with any detector causing such detector to assume the other one of said states, said plurality of detectors being disposed on said first member in sequence along a direction of relative motion between said first member and any of said second members, said detectors being spaced apart from one another, said second member being sized and shaped to provide a length of effectiveness with respect to each of said detectors, along said direction of relative motion, to provide transition from one of said states to the other of only one of said detectors at one time, thereby to provide a pattern of the one of said states in which the various one of said detectors are in having two-N discrete positional zones which are symmetrical with respect to central alignment of said two members with one another, and to provide, when said first member and said second member are in maximum, central alignment along said direction of motion, the two outermost ones of said detectors in one of said states with at least one other of said detectors in another, different one of said states.

2. A position encoder according to claim 1 wherein said detectors are aligned in a single row.

3. A position encoder according to claim 1 wherein said states are further capable of decoding two-N failure conditions.

4. A position encoder according to claim 1 wherein said detectors are arranged in two parallel rows, said rows being parallel to the direction of relative motion of said two members, said two outer detectors being in a first row with each other.

5. The encoder according to claim 4 wherein a second row of said detectors has at least two detectors therein and said second member is shaped so that said two detectors therein are in a state that is opposite to the state of said two outer detectors when said two members are in mutual alignment, whereby the positional extent of the relative positional zones of said encoder are symmetrically, independently adjustable.