Press ring with elongated holes

1. A press ring for pressing tubular workpieces, comprising:

at least two movable press jaws, wherein each movable press jaw has a proximal end and a distal end, and wherein the proximal end of each movable press jaw defines an elongated hole; and

at least one connecting press jaw connecting the movable press jaws;

wherein the movable press jaws are each hinged at their proximal ends to the connecting press jaw by respective bolts, wherein each bolt defines an axis, so that the distal ends of each of the movable press jaws can be rotated about a respective one of the axes towards and away from each other, to receive a workpiece therebetween and to close and open the press ring respectively, and

wherein each bolt is arranged in a respective one of the elongated holes, allowing a translational displacement of the bolts in the elongated holes relative to an associated one of the movable press jaws upon rotation of the at least one of the at least two movable press jaws about a respective one of the axes.

2. The press ring according to claim 1 , wherein the bolts are displaced towards the distal ends of the at least two movable press jaws upon closing of the press ring.

3. The press ring according to claim 1 , wherein the elongated holes are oriented such that at least one of the at least two movable press jaws can be rotated about the associated one of the axes relative to the at least one connecting press jaw as well as moved translationally relative to the at least one connecting press jaw during closing of the press ring.

4. The press ring according to claim 1 , wherein each elongated hole defines an inner wall, wherein each one of the bolts is freely movable along each associated one of the axes relative to an associated one of the elongated holes when the press ring is open and wherein each one of the bolts is abutting the respective inner wall of an associated elongated hole proximate to the distal ends of the at least two movable press jaws when the press ring is closed.

5. The press ring according to claim 1 , wherein rotational movement of each of the at least two movable press jaws about an associated one of the axes defines a rotation angle, which increases when the distal ends of the movable press jaws rotate away from each other, wherein the respective bolts are freely movable in the elongated holes when the rotation angle is larger than a closing angle, wherein the respective bolts are displaced towards the distal ends of the at least two moveable press jaws when the rotation angle is at most a closing angle, and wherein the closing angle is at most 30°.

6. The press ring according to claim 5 wherein the closing angle is at most 15°.

7. The press ring according to claim 6 wherein the closing angle is at most 10°.

8. The press ring according to claim 7 wherein the closing angle is at most 5°.

9. The press ring according to claim 5 , wherein each bolt comprises a recess which comprises a guiding contour,

wherein each elongated hole comprises a driving protrusion extending towards each bolt,

wherein the driving protrusion is located in the recess when the rotation angle is larger than the closing angle and

wherein the guiding contour is formed to guide the driving protrusion and formed to press the driving protrusion against the bolt when the rotation angle is smaller than the closing angle, and

wherein the driving protrusion is located outside the recess and pressed against the bolt when the press ring is closed.

10. The press ring according to claim 9 , wherein only a part of the length of the bolt is provided with the recess.

11. The press ring according to claim 1 , wherein each of the movable press jaws defines a pressing surface, and wherein the pressing surfaces of the at least two movable press jaws are shaped to form a circular ring when the press ring is closed and wherein the elongated holes are oriented substantially perpendicular to the radius of the circular ring.

12. The press ring according to claim 1 , wherein no additional means are provided at the distal ends of the at least two movable press jaws to contact the tubular workpiece during closure of the press ring.

13. The press ring according to claim 12 wherein the distal ends of the at least two movable press jaws are free of protrusions.

14. The press ring according to claim 1 , wherein the connection between the at least two movable press jaws and the at least one connecting press jaw is established at opposite end portions of the at least one connecting press jaw.

15. The press ring according to claim 1 , wherein the bolts are formed as separate parts and affixed to the corresponding jaw.

16. The press ring according to claim 1 , wherein the bolts and the corresponding jaws are integrally formed.

17. The press ring according to claim 1 , wherein all parts of the press ring are produced by milling.

18. The press ring according to claim 1 , wherein the at least two movable press jaws are identically formed.

19. A method of pressing a tubular workpiece with a press ring, the method comprising:

providing a press ring for pressing tubular workpieces, the press ring including at least two movable press jaws, wherein each movable press jaw has a proximal end and a distal end, and wherein the proximal end of each movable press jaw defines an elongated hole, and at least one connecting press jaw connecting the movable press jaws,

wherein the movable press jaws are each hinged at their proximal ends to the connecting press jaw by respective bolts, wherein each bolt defines an axis, so that the distal ends of each of the movable press jaws can be rotated about a respective one of the axes towards and away from each other, to receive a workpiece therebetween and to close and open the press ring respectively, and

wherein each bolt is arranged in a respective one of the elongated holes, allowing a translational displacement of the bolts in the elongated holes relative to an associated one of the movable press jaws upon rotation of the at least one of the at least two movable press jaws about a respective one of the axes;

placing a tubular workpiece between the movable press jaws;

closing the press ring to thereby press the tubular workpiece.