Light projecting goniometer

• US 6,948,252 B2
• Filed: 02/27/2003
• Issued: 09/27/2005
• Est. Priority Date: 02/28/2002
• Status: Expired due to Fees

• Current Assignee: William F. Gibson
• Original Assignee: William F. Gibson
• Inventors: Gibson, William F.
• Primary Examiner(s): Bennett, G. Bradley
• Assistant Examiner(s): Courson, Tania C.
• Application Number:
  US10/375,419
• Publication Number:
  US 20030226268A1
• Time in Patent Office: 943 Days
• Field of Search: 33/1.PT, 33/1.N, 332/86, 33281-282, 332/85, 332/75.R, 33D/IG.21, 33 76-279
• US Class Current: 33/1.0PT
• CPC Class Codes: A61B 5/1071 measuring angles, e.g. using goniometers A61B5/1123 takes precedence
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes

Abstract

This device is a handheld, battery-operated instrument that utilizes light beams to project visible lines for increasing the accuracy in determining angles. A linear potentiometer is incorporated at the pivot point between the two diodes and measures a voltage change based on the angle between the arms of the device.

Claims

1. An apparatus for measuring an angle, comprising:

a means for producing a first beam of light;

a means for producing a second beam of light, wherein said second beam of light is pivotably adjustable so as to move relative to said first beam of light, wherein said means for producing a first beam of light and means for producing a second beam of light comprises;

a common light source, and

splitting means for splitting a beam output by said common light source into the first beam of light and the second beam of light;

means for redirecting at least one of said first and second beams of light from a linear path so as to spread the light and thereby produce a line on a surface where the redirected beam strikes the surface;

circuitry for detecting the angle between the first beam of light and the second beam of light and producing an analog signal indicative thereof; and

a display for displaying an angular value in response to the analog signal.

2. The apparatus of claim 1, further comprising means for displaying said angle between the first beam of light and the second beam of light.

3. The apparatus of claim 2, wherein means for displaying said angle is a liquid crystal display.

4. The apparatus of claim 1, wherein said circuitry for detecting the angle between the first beam of light and the second beam of light includes:

a. a potentiometer having a linear output over a range of rotational motion, said potentiometer having a one component operatively associated with the first beam of light and a second component operatively associated with the second beam of such that a change in the angle between the first beam of light and the second beam of light results in a change of the resistance of the potentiometer;

b. means for measuring the resistance of the potentiometer at a first angle between the beams of light and generating a first signal;

c. means for measuring the resistance of the potentiometer at a second angle between the beams of light and generating a second signal; and

d. a subtractor for automatically comparing the first and second signals and producing an output indicative of the difference between the first and second signals.

5. A goniometer for measuring a range of angular motion of a joint, comprising:

a first arm of the goniometer, said first arm emitting a first laser beam of light from an end thereof in a manner parallel to the first arm;

a second arm pivotably connected to said first arm, said second arm emitting a second laser beam of light from an end thereof in a manner parallel to the second arm, wherein said first and second laser beams are produced by a common laser light source, and second beam splitter for splitting a laser beam output by said common light source into the first laser beam and the second laser beam;

a first beam splitter for redirecting at least one of said first and second beams of laser light from a linear path so as to spread the light and thereby produce a line on a surface where the redirected beam strikes the surface, said surface lying generally parallel and beneath one arm of the goniometer;

a linear potentiometer for detecting an angle between the first arm and its first beam of light and the second arm and its second beam of light and generating a signal representing the angle;

memory for storing at least one signal representing a first angle between the first arm and the second arm; and

a subtractor for automatically determining, based upon the potentiometer signal, the angular difference between the first angle and a current angle as the joint is moved, thereby characterizing the range of angular motion; and

a display for displaying the angular difference.