Highly accurate odometer

• US 3,947,664 A
• Filed: 01/02/1974
• Issued: 03/30/1976
• Est. Priority Date: 01/02/1974
• Status: Expired due to Term

• Current Assignee: Texaco Incorporated (Chevron Corp.)
• Original Assignee: Texaco Incorporated (Chevron Corp.)
• Inventors: Cox, Percy T., Rundell, Herbert A.
• Primary Examiner(s): Thesz, Jr., Joseph M.
• Application Number:
  US05/430,135
• Time in Patent Office: 818 Days
• Field of Search: 235/92 CC, 235/92 PL, 235/92 DN, 328/48
• US Class Current: 377/24
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence

Abstract

An odometer that employs a pulse generator, the pulses of which correspond to a given increment of linear distance. It has a correction circuit which may be set to either add or subtract a pulse after a predetermined number of pulses have been counted. This corrects the linear distance measured for any cumulated total. Consequently, inaccuracies in the dimension represented by each pulse will be periodically compensated for by the added or deleted pulse.

Claims

1. An odometer for accurately measuring long linear lengths, comprising in combination

a wheel driving an electric pulse generator,

said pulse generator producing a first predetermined number of pulses for each predetermined amount of said wheel rotation,

said wheel rotation measuring a predetermined increment of said linear length depending upon the circumference thereof,

a pulse shaper,

a total pulse counter for indicating said long linear length,

a subtotal pulse counter for determining when a second predetermined number of pulses has been reached,

means for comparing a preset count representing said second predetermined number of pulses with said subtotal pulse counter,

a NAND gate for passing a pulse when said preset count has been reached by said subtotal counter,

a selector switch in the input of said total pulse counter,

an add channel for introducing an extra pulse, comprising

a time-delay circuit for delaying said NAND gate pulse at least the width of one of said shaped pulses,

a pulse regenerator, and

an OR gate for passing said total number of shaped pulses in addition to said regenerated pulse to an add side of said selector switch, and a subtract channel for removing a pulse, comprising

a delay and regeneration means connected to the output of said pulse shaper,

an inhibit signal flip-flop having an input connected to receive said NAND gate pulse, and

an inhibit OR gate for passing said delay and regeneration means output to a subtract side of said selector switch, except when said inhibit signal is present.

2. A highly accurate odometer, comprising

means for measuring a predetermined linear distance repeatedly,

an electric pulse generator for producing a signal corresponding to each said distance measurement,

an electronic counter for continuously counting the total number of said signals,

means for determining when a predetermined subtotal count has been reached comprising a second electronic counter,

means for algebraically changing the total count by one,

switch means for selecting whether said change count is added or substracted,

a pulse shaper having an input connected to said pulse generator and plurality of output circuits,

a pair of gates having the outputs thereof connected to said switch means,

one of said pulse shaper output circuits being connected to said subtotal counter means,

another of said pulse shaper output circuits being connected to one of said gates, and

a third of said pulse shaper output circuits being connected to the other of said gates.

3. An odometer according to claim 2, further including

delay and regeneration means connected in series with said third pulse shaper output circuit whereby said continuous electronic counter receives said pulses with a predetermined delay except when a pulse is inhibitied after said subtotal count has been reached.