Calibration fixture for machine vision vehicle wheel alignment system

Patent metadata

Field	Value
Publication number	US-9528822-B2
Application number	US-201414170175-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Feb 8, 2013
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A calibration fixture for use during a calibration procedure of a machine vision vehicle wheel alignment system. The calibration fixture consists of a pair of support legs, and a rotating transverse bar supported within an outer support tube secured between the support legs. The rotating transverse bar is supported within the outer support tube by a pair of annular bearings adjacent each end of the outer support tube, and is isolated from external influences which may result in deflection or distortion. A hub for receiving a sensor or optical target is secured to each end of the rotating transverse bar, such that optical targets mounted to each hub are maintained in axial alignment at opposite ends of the rotating transverse bar.

First claim

The invention claimed is:

1. A calibration fixture for use during a calibration procedure of a machine vision vehicle wheel alignment measurement system, comprising:
a pair of support legs;
a transverse outer support tube secured to, and supported by, said support legs;
a rotatable transverse bar supported within said outer support tube, said rotatable transverse bar having an axis of rotation;
a sensor hub secured at each opposite axial end of said rotatable transverse bar, external to said outer support tube; and
at least one clamping element configured to selectively secure said rotatable transverse bar against axial rotation relative to said outer support tube.

2. The calibration fixture of claim 1 wherein each of said support legs is oriented vertically upward from an underlying support surface upon which it is disposed.

3. The calibration fixture of claim 1 wherein said rotatable transverse bar is supported within said outer support tube by at least a pair of annular bearings; and
wherein at least one annular bearing is disposed adjacent each axial end of the outer support tube.

4. The calibration fixture of claim 1 wherein said sensor hubs are maintained in axial alignment with each other at opposite ends of the rotatable transverse bar.

5. The calibration fixture of claim 1 wherein each sensor hub includes a threaded stem engaging a threaded bore, said threaded bore extending radially from an exterior peripheral surface of said sensor hub to intersect an axial bore within said sensor hub.

6. The calibration fixture of claim 1 wherein said at least one clamping element is further configured to apply a clamping force to said rotatable transverse bar which does not impart statistically significant deflection, movement, or distortion to the rotatable transverse bar and to the associated axis of rotation linking the opposed sensor hubs.

7. The calibration fixture of claim 1 wherein at least one of said pair of support legs is supported on a roller.

8. The calibration fixture of claim 1 wherein said transverse outer support tube is removable from said pair of support legs.

9. The calibration fixture of claim 1 wherein each of said support legs includes an open receiving recess at one end, said transverse outer support tube secured within said receiving recess by engagement between receiving slots on an outer circumference of said transverse outer support tube and an inner sidewall surface of said receiving recess.

10. The calibration fixture of claim 1 wherein said rotatable transverse bar is supported concentrically within said outer support tube and an axis of rotation of said rotatable transverse bar is coaxial with a longitudinal axis of said transverse outer support tube.

11. The calibration fixture of claim 1 wherein an axis of rotation of said rotatable transverse bar is parallel to a longitudinal axis of said transverse outer support tube.

12. The calibration fixture of claim 1 wherein said sensor hubs are secured in axial alignment at opposite axial ends of said rotatable transverse bar.

13. A calibration fixture for use during a calibration procedure of a machine vision vehicle wheel alignment measurement system, comprising:
an outer support tube having a longitudinal axis;
a rotatable member supported within, and extending longitudinally through, said outer support tube, said rotatable member having a longitudinal axis of rotation;
a sensor hub secured at each opposite axial end of said rotatable member, external to said outer support tube, said sensor hubs each coaxial with said longitudinal axis of rotation; and
at least one clamping element configured to selectively secure said rotatable member against axial rotation relative to said outer support tube.

14. The calibration fixture of claim 13 further including a support structure removably coupled to said outer support tube, said support structure configured to position said outer support tube with said longitudinal axis in a stable horizontal orientation elevated above an underlying support surface.

15. The calibration fixture of claim 13 wherein said rotatable member has a longitudinal structure selected from a set of longitudinal structures including, a unitary member, a composite structure, a hollow tubular structure, or a solid elongate structure.

16. The calibration fixture of claim 13 wherein said rotatable member has structural characteristics selected to resist twisting and deflection during rotation about the longitudinal axis of rotation in order to maintain said opposite axial ends in rotational alignment to within a selected tolerance.

17. A method for synchronously rotating a pair of sensor hubs about a common axis of rotation during a calibration procedure of a machine vision vehicle wheel alignment measurement system, comprising:
providing a rotatable transverse member having a longitudinal axis of rotation;
securing a hub to each axial end of said rotatable transverse member in axial alignment with said longitudinal axis of rotation and each other;
supporting said rotatable transverse member for rotation about said longitudinal axis of rotation within an outer support tube;
altering a rotational position of said rotatable transverse member about said longitudinal axis of rotation while said outer support tube is maintained in a stationary configuration;
locking said rotatable transverse member against rotational movement relative to said outer support tube; and
wherein said step of altering said rotational position synchronously alters a rotational position of each of said secured sensor hubs about said longitudinal axis of rotation.

Assignees

• Hunter Eng Co

Inventors

• Stieff Michael T

Classifications

• G01B11/2755 Primary

  using photoelectric detection means · CPC title

• G01B2210/12

  Method or fixture for calibrating the wheel aligner · CPC title