Magnetically triggered on-board elapsed time indicator

• US 4,392,122 A
• Filed: 06/25/1981
• Issued: 07/05/1983
• Est. Priority Date: 06/26/1980
• Status: Expired due to Fees

• Current Assignee: Redvers A. Hocken
• Original Assignee: Redvers A. Hocken
• Inventors: Hocken, Redvers A.
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US06/277,399
• Time in Patent Office: 740 Days
• Field of Search: 340/323 R, 340/309.4, 340/309.1, 340/52 R, 340/62, 340/670, 324/179, 324/160, 73/490, 180/167, 180/168, 180/171, 346/18, 235/92 GA, 235/92 TA
• US Class Current: 340/323.00R
• CPC Class Codes: G01P 3/66 using electric or magnetic means G01P3/80 takes precedence; measuring short time intervals G04F8/00, G04F10/00
• CPC Class Codes: G07C 1/24 Race time-recorders

Abstract

A vehicle such as a speedboat or racing car is equipped with a magnetic sensing coil (22) for producing electrical signals in response to detection of magnets disposed at one or more positions along the course. In the case of buoy-mounted markers, the magnets (26) may be mounted on certain of the buoys (10,13,14,17). The output from the sensing coil (22) is used to control on-board timing circuitry to enable the average vehicle speed over the course to be determined and displayed.

Claims

1. A system for on-board timing for a vehicle traversing a predetermined course, said system comprising sensing coil means adapted to be carried by the vehicle for producing an electrical signal in response to sensing at least one magnet located at at least one predetermined position along said course, on-board timing means and on-board control means responsive to said sensing coil means for controlling operation of the timing means to provide a record of the time interval elapsing between successive or selected electrical signals produced by said sensing coil means.

2. A system as claimed in claim 1 in which said sensing coil means comprises a coil having a core comprising a magnetically permeable material, said coil being disposed in a predetermined orientation on the vehicle so as to attenuate the affect of magnetic fields generated by an engine powering the vehicle and any electrical equipment associated therewith or the affect of the earth'"'"'s magnetic field.

3. A system as claimed in claim 2 in which said magnetically permeable core projects from said coil at at least one end of the latter.

4. A system as claimed in claim 3 in which the total amount by which the core projects from the coil is of the order of 100% the length of the coil.

5. A system as claimed in any one of claims 1 to 4 including means for selectively determining with respect to the magnet the maximum range at which the sensor can produce a detectable signal.

6. A system as claimed in any one of claims 1 to 4 in which the vehicle is a water borne vehicle and said course is defined by a number of buoys, the or each magnet comprising a permanent magnet connected to one or more buoys.

7. A system as claimed in claim 2 in which said coil is orientated so that its axis extends substantially perpendicularly to the fore and aft axis of the vehicle.

8. A system as claimed in claim 7 in which the core projects from at least one end of the coil and the coil is orientated so that its axis is directed generally towards the magnet or magnets as the vehicle passes the same.

9. A system as claimed in claim 7 or 8 in which the coil is disposed with its axis extending predominantly horizontally and the or each magnet is disposed with its polar axis extending predominantly vertically.

10. A system as claimed in any one of claims 7 or 8 in which there are at least two buoys each provided with a magnet so that one buoy can be used for starting the timing means and the other for stopping the timing means.

11. A system as claimed in any one of claims 7 or 8 in which at least one set of three of the aforesaid buoys is provided and in which the timing means comprises two timers so that the buoys of the or each set may be used as entrance, exit and intermediate reference points, the arrangement being such that both timers are started as the boat passes the entrance buoy, one timer is stopped as the boat passes the intermediate buoy and the second timer is stopped as the boat passes the exit buoy.

12. A system as claimed in any one of claims 7 or 8 in which two sets of four of the aforesaid magnet bearing buoys are provided, the two sets being arranged on opposite sides of the course in such a way that the buoys of each set are spaced lengthwise of the course and each buoy of one set is aligned perpendicularly of the course with a respective buoy on the other set so that the first and fourth pairs of buoys constitute entrance and exit buoys, or vice versa depending on the direction of travel, and the other two pairs of buoys constitute intermediate buoys, and in which the timing means comprises two timers which are controlled by said control means in such a way that one timer is started and stopped respectively at the entrance and exit buoys and the second timer is started at the entrance buoys and stopped at one pair of the intermediate buoys, the second timer being stopped at the one pair of intermediate buoys when travelling in one direction and at the other pair of intermediate buoys when travelling in the opposite direction.

13. A system as claimed in any one of claims 7 or 8 in which each magnet is provided on the respective buoy in such a way that the magnetic field strength is substantially isotropic about a vertical axis of symmetry of the buoy.

14. A system as claimed in any one of claims 1 to 4 in which the vehicle is a road vehicle and said cores is constituted by a circuit, said magnet or magnets being located at a predetermined position along said circuit to enable lap timing to be effected.

15. A system as claimed in claim 14 in which there are a plurality of said magnets spaced apart widthwise of the course.

16. A system as claimed in claim 14 in which the or each magnet is embedded beneath the surface of the course.

17. A system as claimed in claim 14 in which the coil is disposed with its axis extending predominantly vertically and the or each magnet is disposed with its polar axis extending predominantly horizontally.