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1. (WO2016010656) OUTILS HYDRAULIQUES À AVANCE RAPIDE
Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

WHAT IS CLAIMED IS:

1. A hydraulic system comprising:

a reservoir adapted to contain hydraulic fluid;

a hydraulic cylinder defining a hollow interior and including a ram disposed therein, the ram defining a first face and an oppositely directed second working face, the interior of the cylinder and the first face of the ram defining a primary chamber, the ram positionable through a first phase of ram extension and a second phase of ram extension;

a pushrod assembly including a housing defining a hollow interior and a pushrod positionably disposed therein, the pushrod defining a first end and an oppositely directed second end, the interior of the housing and the first end of the pushrod defining a secondary chamber, the pushrod and the ram being in at least periodic operable engagement such that extension of the pushrod causes extension of the ram;

wherein the pushrod and housing include provisions to preclude fluid flow between the primary chamber and the secondary chamber when the pushrod is within a range of positions corresponding to the first phase of ram extension, and permit fluid flow between the primary chamber and the secondary chamber when the pushrod is within a range of positions corresponding to the second phase of ram extension.

2. The hydraulic system of claim 1 wherein the provisions include the pushrod defining a circumferential outer surface generally extending between the first end and the second end of the pushrod and a flat surface region extending along a length portion of the pushrod from the first end of the pushrod.

3. The hydraulic system of claim 2 wherein the provisions further include a recessed band extending around at least a portion of the circumference of the pushrod, the recessed band located between the first end and the second end of the pushrod.

4. The hydraulic system of claim 3 wherein the recessed band extends entirely around the circumference of the pushrod.

5. The hydraulic system of claim 3 wherein the flat surface region extends between the first end of the pushrod and the recessed band.

6. The hydraulic system of claim 3 wherein the recessed band is located along the length of the pushrod at a transition location between the range of positions corresponding to the first phase of ram extension and the range of positions corresponding to the second phase of ram extension.

7. The hydraulic system of any one of claims 1-6 wherein the pushrod assembly is free of seals disposed between the pushrod and the interior of the housing.

8. The hydraulic system of any one of claims 1-7 further comprising:

a hydraulic fluid pump;

at least one fluid flow line extending between the reservoir and the primary chamber;

at least one fluid flow line extending between the pump and at least one of the primary chamber and the secondary chamber.

9. The hydraulic system of claim 8 wherein the at least one fluid flow line extending between the pump and at least one of the primary chamber and the secondary chamber includes:

a first fluid flow line providing fluid communication from the pump to the primary chamber; and

a second fluid flow line providing fluid communication from the pump to the secondary chamber.

10. The hydraulic system of claim 9 wherein the first fluid flow line and the second fluid flow line are in parallel with one another.

1 1 . The hydraulic system of claim 9 wherein the first fluid flow line includes a one way valve permitting fluid flow from the pump to the primary chamber at fluid pressures greater than a first pressure and precluding fluid flow from the primary chamber to the pump.

12. The hydraulic system of claim 1 1 wherein the second fluid flow line includes a one way valve permitting fluid flow from the pump to the secondary chamber at fluid pressures greater than a second pressure and precluding fluid flow from the secondary chamber to the pump.

13. The hydraulic system of claim 12 wherein the first pressure is greater than the second pressure.

14. The hydraulic system of any one of claims 1 -13 wherein the first face of the ram constituting a portion of the primary chamber has a surface area greater than a surface area of the first end of the pushrod constituting a portion of the secondary chamber.

15. A method of extending a hydraulic ram in which the ram is extended at a first rate of extension and then at a second rate of extension, wherein the first rate of extension is greater than the second rate of extension, the method comprising:

providing a hydraulic system including (i) a reservoir containing hydraulic fluid, (ii) a hydraulic cylinder and ram positionably disposed therein, the cylinder and ram defining a primary chamber, (iii) a pushrod assembly having a housing and a pushrod positionably disposed therein, the housing and pushrod defining secondary chamber, the pushrod and the ram being in at least periodic operable engagement such that extension of the pushrod causes extension of the ram, and (iv) provisions for precluding fluid flow between the primary chamber and the secondary chamber at a first range of positions of the pushrod and permitting fluid flow between the primary chamber and the secondary chamber at a second range of positions of the pushrod relative to the housing;

directing hydraulic fluid into the secondary chamber to thereby extend the pushrod and cause extension of the ram, such ram extension occurring at a first rate of extension;

directing hydraulic fluid into the primary chamber to thereby extend the ram at a second rate of extension;

whereby the first rate of extension is greater than the second rate of extension.

16. The method of claim 15 whereby directing hydraulic fluid into the secondary chamber to extend the pushrod includes extending the pushrod through at least a portion of the first range of positions at which fluid flow between the primary chamber and the secondary chamber is precluded.

17. The method of claim 15 whereby directing hydraulic fluid into the primary chamber to extend the ram includes extending the pushrod through at least a portion of the second range of positions at which fluid flow between the primary chamber and the secondary chamber is permitted.

18. The method of claim 15 whereby directing hydraulic fluid into the primary chamber includes directing hydraulic fluid into the secondary chamber.

19. A hydraulic tool comprising:

a tool body;

a tool head secured to the tool body, the tool head including a positionable work member for performing at least one operation on a workpiece;

a hydraulic system generally disposed within the tool body, the hydraulic system including (i) a reservoir adapted to contain hydraulic fluid, (ii) a hydraulic cylinder defining a hollow interior and including a ram disposed therein, the ram defining a first face and an

oppositely directed second working face, the interior of the cylinder and the first face of the ram defining a primary chamber, the ram positionable through a first phase of ram extension and a second phase of ram extension, and (iii) a pushrod assembly including a housing defining a hollow interior and a pushrod positionably disposed therein, the pushrod defining a first end and an oppositely directed second end, the interior of the housing and the first end of the pushrod defining a secondary chamber, the pushrod and the ram being in at least periodic operable engagement such that extension of the pushrod causes extension of the ram, wherein the pushrod and housing include provisions to preclude fluid flow between the primary chamber and the secondary chamber when the pushrod is within a range of positions corresponding to the first phase of ram extension, and permit fluid flow between the primary chamber and the secondary chamber when the pushrod is within a range of positions corresponding to the second phase of ram extension;

wherein the ram is engaged with the work member of the tool head.

20. The hydraulic tool of claim 19 wherein the provisions include the pushrod defining a circumferential outer surface generally extending between the first end and the second end of the pushrod and a flat surface region extending along a length portion of the pushrod from the first end of the pushrod.

21 . The hydraulic tool of claim 20 wherein the provisions further include a recessed band extending around at least a portion of the circumference of the pushrod, the recessed band located between the first end and the second end of the pushrod.

22. The hydraulic tool of claim 21 wherein the recessed band extends entirely around the circumference of the pushrod.

23. The hydraulic tool of claim 21 wherein the flat surface region extends between the first end of the pushrod and the recessed band.

24. The hydraulic tool of claim 21 wherein the recessed band is located along the length of the pushrod at a transition location between the range of positions corresponding to the first phase of ram extension and the range of positions corresponding to the second phase of ram extension.

25. The hydraulic tool of any one of claims 19-24 wherein the pushrod assembly is free of seals disposed between the pushrod and the interior of the housing.

26. The hydraulic tool of any one of claims 19-25 wherein the hydraulic system further includes (iv) a hydraulic fluid pump, (v) at least one fluid flow line extending between the reservoir and the primary chamber, and (vi) at least one fluid flow line extending between the pump and at least one of the primary chamber and the secondary chamber.

27. The hydraulic tool of claim 26 wherein the at least one fluid flow line extending between the pump and at least one of the primary chamber and the secondary chamber includes:

a first fluid flow line providing fluid communication from the pump to the primary chamber; and

a second fluid flow line providing fluid communication from the pump to the secondary chamber.

28. The hydraulic tool of claim 27 wherein the first fluid flow line and the second fluid flow line are in parallel with one another.

29. The hydraulic tool of claim 27 wherein the first fluid flow line includes a one way valve permitting fluid flow from the pump to the primary chamber at fluid pressures greater than a first pressure and precluding fluid flow from the primary chamber to the pump.

30. The hydraulic tool of claim 29 wherein the second fluid flow line includes a one way valve permitting fluid flow from the pump to the secondary chamber at fluid pressures greater than a second pressure and precluding fluid flow from the secondary chamber to the pump.

31. The hydraulic tool of claim 30 wherein the first pressure is greater than the second pressure.

32. The hydraulic tool of any one of claims 19-31 wherein the first face of the ram constituting a portion of the primary chamber has a surface area greater than a surface area of the first end of the pushrod constituting a portion of the secondary chamber.

33. The hydraulic tool of any one of claims 19-32 wherein the tool body defines a tool head end and the tool head is removably secured to the tool body at the tool head end.

34. The hydraulic tool of claim 33 wherein the tool head end is generally cylindrical and the tool head defines a proximal end with a cylindrical bore sized and shaped to receive the cylindrical tool head end.