BALL TRACKER ASSEMBLY

• US 3,643,148 A
• Filed: 04/16/1970
• Issued: 02/15/1972
• Est. Priority Date: 04/16/1970
• Status: Expired due to Term

• Current Assignee: Arthur Brown, Thomas W. Wong
• Original Assignee: Arthur Brown, Thomas W. Wong
• Inventors: Brown, Arthur, Wong, Thomas W.
• Primary Examiner(s): Dobeck, Benjamin
• Application Number:
  US05/029,144
• Time in Patent Office: 670 Days
• Field of Search: 318/628,83 244/83B,83.91 74/471
• US Class Current: 318/628
• CPC Class Codes: G01S 13/66 Radar-tracking systems; Analogous systems
• CPC Class Codes: G05D 3/121 using synchromachines (selsyns)
• CPC Class Codes: Y10T 74/20012 Multiple controlled elements
• CPC Class Codes: Y10T 74/20201 Control moves in two planes

Abstract

A ball tracker adapted for use in polar coordinate axis systems employs a rotating subframe including a rotatably mounted ball member and two ball rotation responsive sensors disposed 90* apart along the median ball circumference. The electronic output of the two sensors comprises polar coordinate range (r) and angle ( theta ) parameters, and feedback apparatus maintains the range sensor spatially aligned in an angular direction determined by the output of the angle sensor. A controlled environment ordered in polar coordinates, e.g., a cursor position in a polar cathode-ray tube display, may be regulated by actuating the ball tracker in a manner which is conceptually compatible with the natural predictions of a tracker operator.

Claims

1. Tracker apparatus of the type having a fixed tracker housing, mechanical means adapted for motion by an operator, two sensors each responsive to a different motion of the mechanical means and each providing an output signal, wherein the improvement comprises:

a subframe rotatably mounted within said housing and having said two sensors mechanically coupled thereto for rotation therewith; and

feedback means for rotating said subframe and said sensors in a direction determined by the output signal of one of said sensors.

2. Tracker apparatus as in claim 1 wherein said mechanical means includes a ball mounted for rotation and secured on said subframe.

3. Tracker apparatus as in claim 2 wherein each of said sensors includes a wheel engaging said ball periphery, and means connected to each of said wheels for providing different output signals depending upon the rotational position of said wheels.

4. Tracker apparatus as in claim 3 wherein said wheels of said sensors are spaced 90* apart about said ball periphery.

5. Tracker apparatus as in claim 4 further comprising signal receiving means, means including sliprings for coupling signals from said sensors on said subframe to said signal receiving means.

6. Tracker apparatus as in claim 5 wherein said feedback means includes a position sensor and a motor each secured to said fixed housing, and mechanical coupling means connecting said rotating subframe with said position sensor and said motor.

7. Tracker apparatus as in claim 1 wherein feedback means includes a position sensor and a motor each secured to said fixed housing, and mechanical coupling means connecting said rotatable subframe with said position sensor and said motor.

8. Tracker assembly as iN claim 7 wherein said fixed housing includes a track, and wherein said subframe includes roller means for translating within said track.