System for accurately punching holes in a profile and its method

1 . A system for accurately punching holes in a profile comprising:

at least one clamp unit, comprising a clamp, slideable in a first direction, and

at least one punch unit for punching holes in a profile,

characterized in that, the at least one clamp unit comprises a linear encoder, configured for measuring a displacement of the clamp of the at least one clamp unit in the first direction, and a temperature sensor configured for measuring the temperature of the linear encoder; and the at least one punch unit comprises a displacement sensor comprising a linear encoder configured for measuring a displacement of the profile in a direction transverse to the first direction, relative to an axis in the first direction.

2 . The system according to claim 1 , wherein the system comprises at least two clamp units, each clamp unit comprising a clamp slideable in the first direction, wherein the at least one punch unit is positioned in between two of the at least two clamp units and wherein each of the two of the at least two clamp units comprises a linear encoder, configured for measuring a displacement of the clamp of the at least two clamp units in the first direction.

3 . The system according to claim 1 , wherein the at least one clamp unit comprises a slippage sensor configured for detecting slippage of the profile in the clamp of the at least one clamp unit, wherein the slippage sensor comprises a magnet configured for magnetic attraction to a magnet reference position on the profile, wherein slippage of the profile in the clamp of the at least one clamp unit displaces the magnet to a new position on the profile, wherein the slippage sensor comprises means for measuring the displacement of the magnet in the first direction between the magnet reference position and the new position, thereby measuring the amount of the slippage.

4 . The system according to claim 3 , wherein the slippage sensor comprises an arm, having a first and a second end, wherein the arm is at the first end attached to an attachment point on the clamp, wherein the arm comprises the magnet at the second end, and wherein the magnet is moveable relative to the attachment point of the clamp.

5 . The system according to claim 1 , wherein the displacement sensor comprises a group of at least three measuring wheels, wherein each measuring wheel is coupled to a corresponding linear encoder, wherein the measuring wheels of the group are equidistantly spread along an axis in the first direction, and wherein the group is positioned at a passage for the profile.

6 . The system according to claim 1 , wherein the at least one punch unit comprises a drive, configured for displacing the punch unit in a direction transverse to the first direction.

7 . A method for accurately punching holes in a profile comprising:

clamping a profile in a clamp of a clamp unit,

displacing the profile in a punch unit by sliding the clamp in a first direction,

measuring a position of a longitudinal edge of the profile in a direction transverse to the first direction, relative to an axis in the first direction, with a linear encoder comprised in a displacement sensor of the punch unit, and

punching at least one hole in the profile by the punch unit,

characterized in that, the displacement of the profile in the first direction is measured with a linear encoder and the temperature of the linear encoder is measured by a temperature sensor, comprised in the clamp unit.

8 . The method according to claim 7 , wherein, the displacement measurement with the linear encoder is temperature compensated.

9 . The method according to claim 7 an additional step of verifying said position of said longitudinal edge of the profile relative to said axis in the first direction after adjusting the position of the punch unit.

10 . The method according to claim 7 , wherein the method comprises an additional step of making a reference hole in the profile.

11 . The method according to claim 7 , wherein the profile is a U-profile for a truck or trailer chassis, and wherein the punching at least one hole in the profile by the punch unit comprises punching at least one hole in a web and/or one or more flanges of the U-profile.