Double nut tensioner assembly for pre-stretched tie rods

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Quick Facts

Patent No.: US 6,938,450
App. No.: 10/359,695
Granted: Sep 6, 2005
Kind: B1

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Abstract

The tensioner assembly is provided for clamping at least two objects and comprises a tie rod member, a thrust ring positioned on the tie rod member against one of the objects, a first retaining member for removably engaging a distal end of the tie rod member, and a second retaining member for removably engaging the distal end of the tie rod member between the thrust ring and said first nut member and spaced apart therefrom. Each of the first and second retaining members is provided with a set of jackbolts adapted to engage complementary holes therein and to extend from the holes to compressively bias the thrust ring. The total load experienced by the tensioner assembly is shared by two retaining members so that load carried by the first retaining member remains substantially constant during operation, while the second retaining member is subject to stress variation.

Claims (36)

1. A tensioner assembly for detachably clamping at least two objects, said tensioner assembly comprising:

an elongated tie rod member;

a first nut member for removably engaging one of distal ends of said tie rod member, said first nut member having a plurality of threaded holes at spaced apart locations in said first nut member, said holes extending substantially parallel to said tie rod member;

a first set of jackbolts adapted to threadably engage said holes in said first nut member, said jackbolts being provided to extend from said holes to compressively bias said at least two objects;

a second nut member for removably engaging said one of said distal ends of said tie rod member, said second nut member positioned on said tie rod member between said thrust ring and said first nut member and axially spaced therefrom, said second nut member having a plurality of threaded holes at spaced apart locations in said second nut member, said holes extending substantially parallel to said rod member; and

a second set of jackbolts adapted to threadably engage said holes in said second nut member, said jackbolts being provided to extend from said holes to compressively bias said at least two objects;

wherein said jackbolts are adapted to being torqued to a predetermined value to pre-load said tie rod member to a predetermined pre-load.

2. The tensioner assembly as defined in claim 1 , said tensioner assembly further comprising a thrust member concentrically positioned on said tie rod member against one of said at least two objects, wherein said first set of jackbolts is provided to extend from said holes to compressively bias said thrust ring against one of said at least two objects, and said second set of jackbolts is provided to extend from said holes to compressively bias said thrust ring against one of said at least two objects.

3. The tensioner assembly as defined in claim 1 , wherein said first nut member is primarily subjected to substantially constant pre-load and said second nut member is primarily subjected to substantially varying additional forces generated during operation of said at least two objects.

4. The tensioner assembly as defined in claim 1 , wherein said thrust member has a pressure contact surface engaging said one of said at least two objects, a first support surface engaging said first set of said jackbolts and a second support surface engaging said second set of said jackbolts.

5. The tensioner assembly as defined in claim 1 , wherein said first nut member has a centrally located threaded through bore for threadedly engaging a cooperating threaded portion of said one of said distal ends of said tie rod member, and said plurality of said threaded holes are spaced from and surrounding said through bore.

6. The tensioner assembly as defined in claim 5 , wherein said first nut member has a substantially cylindrical peripheral side surface.

7. The tensioner assembly as defined in claim 5 , wherein said first nut member has a substantially hexagonal peripheral side surface.

8. The tensioner assembly as defined in claim 1 , wherein said second nut member has a centrally located threaded through bore for threadedly engaging a cooperating threaded portion of said one of said distal ends of said tie rod member, and said plurality of said threaded holes are spaced from and surrounding said through bore.

9. The tensioner assembly as defined in claim 8 , wherein said second nut member has a substantially cylindrical peripheral side surface.

10. The tensioner assembly as defined in claim 1 , wherein said thrust member has a cup-shaped body provided with a central through hole adapted to receive said tie rod member therethrough, a pressure contact surface in contact with one of said at least two objects, a first support surface facing said first nut member, and a second support surface facing said second nut member, said first support surface abuts said jackbolts provided in said first nut member and said second support surface abuts said jackbolts provided in said second nut member.

11. The tensioner assembly as defined in claim 1 , wherein said tie rod member extends through said at least two objects.

12. The tensioner assembly as defined in claim 1 , wherein said at least two objects are lower and upper platens of a hydro-forming press apparatus.

13. The tensioner assembly as defined in claim 12 , wherein said hydro-forming press apparatus further includes at least one substantially cylindrical compression tube sandwiched between said lower and upper platens.

14. The tensioner assembly as defined in claim 13 , wherein said tie rod member extends through said lower and upper platens and said at least one compression tube.

15. A hydro-forming press apparatus comprising:

a lower platen;

an upper platen;

at least one tie rod member extending through said lower and upper platens, said at least one tie rod member having a pair of opposite distal ends; and

a tensioner assembly disposed on one of said opposite distal ends of said at least one tie rod member, said at least one tensioner assembly comprising:

a thrust member concentrically positioned on said tie rod member against said one of said upper platen and said lower platen;

a first nut member for removably engaging said one of said opposite distal ends of said at least one tie rod member, said first nut member having a plurality of threaded holes at spaced apart locations in said first nut member, said holes extending substantially parallel to said at least one tie rod member;

a first set of jackbolts adapted to threadably engage said holes in said first nut member, said jackbolts being provided to extend from said holes to compressively bias said thrust member against one of said upper platen and said lower platen;

a second nut member for removably engaging said one of said opposite distal ends of said at least one tie rod member; said second nut member positioned between said thrust ring and said first nut member and axially spaced therefrom, said second nut member having a plurality of threaded holes at spaced apart locations in said second nut member, said holes extending substantially parallel to said rod member; and

a second set of jackbolts adapted to threadably engage said holes in said second nut member, said jackbolts being provided to extend from said holes to compressively bias said thrust ring against one of said upper platen and said lower platen;

wherein said jackbolts are adapted to being torqued to a predetermined value to pre-load said tie rod member to a predetermined pre-load.

16. The hydro-forming press apparatus as defined in claim 15 , wherein said first nut member is primarily subjected to substantially constant pre-load and said second nut member is primarily subjected to substantially varying additional forces generated during operation of said hydro-forming press apparatus.

17. The hydro-forming press apparatus as defined in claim 15 , wherein each of said first nut member and said second nut member has a centrally located threaded through bore for threadedly engaging a cooperating threaded portion of said one of said opposite distal ends of said at least one tie rod member, and said plurality of said threaded holes are spaced from and surrounding said through bore.

18. The hydro-forming press apparatus as defined in claim 15 , wherein said thrust member has a cup-shaped body provided with a central through hole adapted to receive said at least one tie rod member therethrough, a pressure contact surface in contact with one of said upper platen and said lower platen, a first support surface facing said first nut member, and a second support surface facing said second nut member, said first support surface abuts said jackbolts provided in said first nut member and said second support surface abuts said jackbolts provided in said second nut member.

19. The hydro-forming press apparatus as defined in claim 15 , wherein each of said first and second nut members has a substantially cylindrical peripheral side surface.

20. The hydro-forming press apparatus as defined in claim 15 , further comprising a second tensioner assembly disposed on the other of said distal ends of said at least one tie rod member opposite to and substantially identical to said tensioner assembly.