Laser calibration apparatus

Apparatus for measuring straightness in at least one plane and at least one of pitch and yaw in the movement of a first body with respect to a second body along an axis, the apparatus comprising:

• a transmitter unit mountable on the first body;
• an optic unit mountable on the second body;
• wherein the transmitter unit directs at least one light beam towards the optic unit;
• wherein one of the transmitter unit and the optic unit is provided with at least one detector to detect two or more light beams,
• wherein the detection method for each light beam is substantially the same;
• and wherein the displacement of the two or more light beams incident on the at least one detector enables measurement of straightness error in at least one plane and at least one of pitch and yaw during said movement of the first body relative to the second body.

Apparatus for measuring squareness of the axes of a machine having first and second parts movable relative to one another, the apparatus comprising:

• a base unit mountable on the first machine part;
• a transmitter unit mountable on the base unit, the base unit and at least one surface of the transmitter unit being provided with cooperating elements to define the position of the transmitter unit relative to the base unit in a plurality of known relative orientations of the transmitter unit and thereby define the directions of at least one light beam;
• an optic unit mounted on the second machine part;
• wherein the transmitter unit directs at least one light beam towards the optic unit;
• wherein one of the transmitter unit and the optic unit is provided with one or more detectors to detect one or more light beams transmitted to or reflected from the optic unit;
• such that by orientating the transmitter unit along two axes of the base unit and measuring the lateral displacement of the at least one light beam on the at least one detector, the squareness of those two axes can be determined.

Apparatus for measuring deviation in the movement of a first body with respect to a second body comprising:

• a transmitter unit mountable on the first body;
• an optic unit mountable on the second body;
• wherein the transmitter unit directs at least one light beam towards the optic unit;
• wherein one of the transmitter unit and the optic unit is provided with one or more detectors to detect one or more light beams transmitted to or reflected from the optic unit;
• wherein the position of the light beam on the detector is used as feedback to adjust the position of the transmitter unit or change the movement vector of the second body in order to maintain the light beam on the detector during relative movement of the first and second bodies.