Chassis sag and bow measurement system

1 . An apparatus including:

a frame including a first elongated member and first mounting points on a first side and a second elongated member and second mounting points on a second side parallel to the first side, the first and second elongated members lying in a first plane defined by a first axis perpendicular to the first and second elongated members and a second axis parallel to the first and second elongated members;

a first cross member connected between the first elongated member and the second elongated member and movable with respect to the first and second elongated members parallel to the second axis;

a first bracket connected to the first cross member and moveable along the first cross member between the first and second elongated members; and

a first range finder connected to the first bracket and oriented parallel to a third axis perpendicular to the first plane, the range finder providing data indicating a distance along the third axis.

2 . The apparatus of claim 1 , further including a second range finder oriented parallel to the first axis and a third range finder oriented parallel to the second axis, the second range finder providing data indicating a second distance along the first axis and the third range finder providing data indicating a third distance along the third axis.

3 . The apparatus of claim 2 , wherein the first range finder includes a gauge including a probe and the first distance includes a first length the probe has extended from an initial position.

4 . The apparatus of claim 3 , wherein the second range finder includes a first draw wire gauge or a first linear encoder, and the third range finder includes a second draw wire gauge or a second linear encoder.

5 . The apparatus of claim 4 , wherein the frame includes first, second, third, and fourth corner brackets, the first and second corner brackets configured to be connected to a first rail oriented parallel to the first side and the third and fourth corner brackets configured to be connected to a second rail oriented parallel to the second side.

6 . The apparatus of claim 5 , wherein the first elongated member is configured to be connected to the first and second corner brackets and the second elongated member is configured to be connected to the third and fourth corner brackets, the first and second corner brackets repositionable with respect to the first elongated member along the second axis, the third and fourth corner brackets repositionable with respect to the second elongated member along the second axis.

7 . The apparatus of claim 6 , wherein the frame includes first and second inner brackets, the first inner bracket connected to the first elongated member and movable with respect to the first elongated members parallel to the second axis, the second inner bracket connected to the second elongated member and movable with respect to the second elongated member parallel to the second axis, the first and second inner brackets cooperating to maintain the first cross member parallel to the first axis.

8 . The apparatus of claim 7 , the frame further including third and fourth elongated members oriented parallel to the first cross member, the third elongated member connected between the second and third corner brackets and the fourth elongated member connected between the fourth and first corner brackets, wherein:

the first and second inner brackets are repositionable with respect to the first cross member along the first axis,

the second and third corner brackets are repositionable with respect to the third elongated member along the first axis, and

the fourth and first corner brackets are repositionable with respect to the fourth elongated member along the first axis.

9 . The apparatus of claim 8 , wherein the first range finder is repositionable with respect to the first bracket such that the first range finder may be oriented in a first direction parallel to the third axis and a second direction opposite the first direction.

10 . The apparatus of claim 1 , wherein the range finder includes a first optical range finder and the distance along the third axis includes a first length from the first optical range finder.

11 . The apparatus of claim 10 , further including a second optical range finder oriented parallel to the first axis and a third optical range finder oriented parallel to the second axis, the second optical range finder providing data indicating a second distance along the first axis and the third optical range finder providing data indicating a third distance along the third axis.

12 . A method for measuring chassis sag or bow, the method including:

positioning a frame in a rack, the frame having a first range finder that is at least one of slidably or rotatably mounted on an elongated frame cross-member, the elongated frame cross-member being in a first position with respect to the frame and slidable within a plane parallel to the frame, the first range finder being configured to measure a first distance relative to the first range finder and a first chassis installed in the rack, the first distance being measured in one of a first direction perpendicular to the plane or a second direction perpendicular to the plane;

determining a first position of the first range finder in the plane;

measuring the first distance relative to the first range finder and the first chassis in one of the first direction or the second direction; and

determining, using the first distance, at least one of a first sag value or a first bow value of the first chassis at the first position.

13 . The method of claim 12 , positioning the frame in the rack below the first chassis such that the first range finder measures the first distance relative to the first range finder and the first chassis mounted above the first range finder in the first direction and determines the first sag value.

14 . The method of claim 12 , positioning the frame in the rack above the first chassis such that the first range finder measures the first distance relative to the first range finder and the first chassis mounted below the first range finder in the second direction and determines the first bow value.

15 . The method of claim 12 , wherein positioning the frame in the rack includes positioning the frame in the rack below the first chassis and above a second chassis, the method further comprising:

rotating the first range finder on the frame cross-member;

measuring a second distance relative to the first range finder and the second chassis in the second direction; and

determining, using the second distance, the first bow value of the second chassis at the first position.

16 . The method of claim 13 , further comprising:

sliding at least one of the frame cross-member along a first axis within the plane parallel to the frame or the first range finder along a second axis within the plane perpendicular to the first axis;

determining a second position of the first range finder in the plane;

measuring a second distance relative to the first range finder and the first chassis in the first direction; and

determining, using the second distance, a second sag value of the first chassis at the second position.

17 . The method of claim 14 , further comprising:

sliding at least one of the frame cross-member along a first axis within the plane parallel to the frame or the first range finder along a second axis within the plane perpendicular to the first axis;

determining a second position of the first range finder in the plane;

measuring a second distance relative to the first range finder and the first chassis in the second direction; and

determining, using the second distance, a second sag value of the first chassis at the second position.

18 . The method of claim 15 , further comprising:

sliding at least one of the frame cross-member along a first axis within the plane parallel to the frame or the first range finder along a second axis within the plane perpendicular to the first axis;

determining a second position of the first range finder in the plane;

measuring a third distance relative to the first range finder and the first chassis in the first direction at the second position of the first range finder;

determining, using the third distance, a second sag value of the first chassis at the second position of the first range finder;

rotating the range finder on the frame cross-member;

measuring a fourth distance relative to the first range finder and the second chassis in the second direction at the second position of the first range finder; and

determining, using the fourth distance, a second bow value of the second chassis at the second position of the first range finder.

19 . The method of claim 12 , wherein determining the first position of the first range finder in the plane comprises:

determining a second distance of the first range finder along the first axis using a second range finder positioned parallel to the first axis; and

determining a third distance of the first range finder along the second axis using a third range finder positioned parallel to the second axis parallel to the frame cross-member, the second distance and the third distance providing the first position of the first range finder.

20 . The method of claim 12 , further comprising:

sliding at least one of the frame cross-member along a first axis within the plane parallel to the frame or the first range finder along a second axis within the plane perpendicular to the first axis;

determining a second position of the first range finder in the plane;

measuring a second distance relative to the first range finder and the first chassis in the second direction; and

determining a first sage value or a first bow value of the first chassis as a difference between the first distance and the second distance.