Dual end stop actuator and method

• US 20020129701A1
• Filed: 04/19/2002
• Published: 09/19/2002
• Est. Priority Date: 12/14/2000
• Status: Active Grant

• Current Assignee: Wirematic Trutorq AB (Mekanotjänst Holding CF AB)
• Original Assignee: Trutorq Mekanotjanst Ltd.
• Inventors: Niessen, Leopold J.
• Granted Patent: US 6,604,449 B2
• Time in Patent Office: Days
• US Class Current: 92/120
• CPC Class Codes: F15B 15/065 the motor being of the rack-and-pinion type
• CPC Class Codes: F15B 15/24 for restricting the stroke
• CPC Class Codes: F16K 1/221 specially adapted operating means therefor operating means per se F16K31/00
• CPC Class Codes: F16K 1/523 for limiting the maximum flow rate, using a stop

Abstract

A dual end stop is provided for setting precise open and closed positions for the valve to which the pneumatic actuator is attached. In a preferred embodiment, a stop assembly housing contains two stop adjustment bolts as well as a cam that defines first and second stop surfaces. The stop assembly housing is preferably mounted to the actuator housing outside of the pressurized zone contained by the actuator housing. The stop bolts and associated threaded apertures are designed for minimum overhang of the stop bolts to provide more support. The stop assembly housing not only preferably houses the stop assembly components but also preferably serves as an adaptor plate for the various valves to which the actuator may be mounted. The stop bolts preferably have a convex head to provide a defined point contact rather than a random point contact as may be produced with flat heads. The cam is preferably mounted between two directly adjacent bearings, at least one of which is preferably located in the stop assembly housing. The stop assembly housing is milled to fit precisely within a recess in the actuator housing for improved support and more accurate alignment as well as eliminating the need for machining more than two bolt holes for attaching the stop assembly housing to the actuator housing.

Claims

1. A dual end stop for a pneumatic actuator, said pneumatic actuator comprising an actuator housing, said actuator housing having a zone for pressure containment, a rotary drive element mounted for rotation within said actuator housing, said dual end stop comprising:

a first stop surface and a second stop surface mounted for stopping said rotary drive element in a corresponding first rotational position and a second rotational position;

a first stop member for engaging said first stop surface, said first stop member being mounted outside of said zone for pressure containment; and

a second stop member for engaging said second stop surface, said second stop member being mounted outside of said zone for pressure containment.

2. The dual end stop of claim 1, further comprising:

a stop assembly housing defining an aperture therein, said stop assembly housing being mounted to said actuator housing, a stop element being positioned within said stop assembly housing and defining thereon said first stop surface and said second stop surface.

3. The dual end stop of claim 2, further comprising:

a first bearing for said rotary drive element mounted adjacent a first side of said stop element, and a second bearing for said rotary drive mounted adjacent a second side of said stop member opposite to said first side.

4. The dual end stop of claim 2, wherein a third bearing for said rotary drive element is mounted on an opposite side of said rotary drive element and axially spaced from said first bearing and said second bearing.

5. The dual end stop of claim 1, further comprising a first threaded portion for said first stop member threadably engaged with a threaded receptacle, at least eighty percent of said first threaded portion threadably engaged said threaded receptacle so as to be supported within said receptacle.

6. The dual end stop of claim 1, further comprising a rounded end for said first stop member, said rounded end engagable with said first stop surface.

7. A method for an adjustable dual end stop for use with a pneumatic actuator, an actuator housing for said pneumatic actuator, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing, said dual end stop comprising

providing said rotary drive element with a first stop surface and a second stop surface such that said first stop surface and said second stop surface are positioned outside of said zone for pressure containment;

providing a first stop member for engaging said first stop surface to stop said rotary drive element in a first rotational position, said first stop member being moveable relative to said stop surface for adjusting said first rotational position; and

providing a second stop member for engaging said second stop surface to stop said rotary drive element in a second rotational position, said second stop member being moveable relative to said stop surface for adjusting said second rotational position.

8. The method of claim 7, further comprising:

mounting said first stop member and said second stop member within a stop assembly housing.

9. The method of claim 8, further comprising:

providing an aperture within said stop assembly housing, providing a first radiuused section as part of said aperture adjacent said first stop member.

10. The method claim 7, further comprising:

providing a rounded end surface for said first stop member such that said rounded end surface is engagable with said first stop surface.

11. The method of claim 10, further comprising:

providing support for said first stop member such that said stop member is threadably supported at a position closely adjacent said rounded end.

13. The dual end stop adjustment of claim 12, wherein said stop assembly housing is machined to a desired size to thereby mate to said recess and said recess is machined to a size for receiving said stop assembly housing such that lateral movement of said stop assembly housing within said recess is prevented.

14. The dual end stop adjustment of claim 13, wherein said stop assembly housing and said recess are machined to a tolerance of less than or equal to one-one thousandth of an inch for a tight fit of said stop assembly housing within said recess.

15. The dual end stop adjustment of claim 12, wherein:

said stop assembly housing is held in position with respect to said housing with no more than two threaded connectors.

16. The dual end stop adjustment of claim 12, further comprising:

an outer bearing for said rotary drive element mounted within said stop assembly housing, said bearing being on an opposite side of said stop element from said actuator housing.

17. The dual end stop adjustment of claim 16, further comprising:

an inner bearing for said rotary drive element mounted within said actuator housing adjacent said stop assembly housing.

18. The dual end stop of claim 12, further comprising:

a first convex head for said first stop member, said first convex head being engageable with said first stop surface.

19. The dual end stop of claim 18, further comprising:

a first relief groove defined in said stop assembly housing adjacent said first convex head.

12. A dual end stop adjustment for a rotary actuator, comprising:

an actuator housing for said pneumatic actuator, said actuator housing having a zone for pressure containment, said actuator housing having a recess, a rotary drive element rotatably mounted within said actuator housing;

a stop assembly housing sized to fit into said recess, said stop assembly housing defining an aperture therein;

a stop element on said rotary drive element for rotation therewith, said stop element having a first stop surface and a second stop surface, said stop element being positioned within said aperture;

a first stop member for engaging said first stop, said first stop member being mounted within said stop assembly housing such that said first stop member is positionally adjustable; and

a second stop member for engaging said second stop surface, said second stop member being mounted within said stop assembly housing such that said second stop member is positionally adjustable.

20. A method for a dual end stop adjustment for a rotary actuator, said rotary actuator having an actuator housing, said rotary actuator having a rotary shaft rotatably mounted within said actuator housing, said method comprising:

machining a receptacle in the actuator housing;

machining sides of a stop assembly housing that is insertable into said receptacle, said steps of machining providing a tolerance between said receptacle and said stop assembly housing such that said stop assembly housing is prevented from lateral movement; and

providing an aperture within said stop assembly housing for receiving a portion of said rotary shaft.

21. The method of claim 20, further comprising:

mounting a first stop member within said stop assembly housing,

mounting a second stop member within said stop assembly housing, and

providing a first stop surface and a second stop surface on said rotary shaft such that said first stop member is engageable with said first stop surface and said second stop surface is engageable with said second stop surface.

22. The method of claim 21, further comprising:

providing a curved surface on said first stop member, said curved surface of said first stop member being engageable with said first stop surface.

23. The method of claim 21, further comprising:

providing an engagement surface on said first stop member for engaging said first stop surface, and

providing a groove in said stop assembly housing adjacent said engagement surface of said first stop member.

24. The method of claim 20, further comprising:

providing an outer bearing for said rotary shaft within said stop assembly housing.

25. The method of claim 20, further comprising:

providing an inner bearing in said actuator housing adjacent to said stop assembly housing.

27. The dual end stop of claim 26, wherein said stop assembly housing is mounted outside of said zone for pressure containment.

28. The dual end stop of claim 26, wherein said first end stop has a curved surface, and said second end stop has a curved surface.

29. The dual end stop of claim 26, further comprising a bearing mounted within said stop assembly housing for supporting said rotary drive element.

26. A dual end stop for a pneumatic actuator, an actuator housing for said pneumatic actuator, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing, said dual end stop comprising:

a stop assembly housing mountable to said housing, said stop assembly housing having an aperture therein for receiving a portion of said rotary drive element;

a stop element having a first stop surface and a second stop surface, said stop element being positioned within said aperture;

a first stop member having a first end stop, said first end stop being engagable with said first stop surface;

a second stop member having a second end stop, said second end stop being engagable with said second stop surface, said stop assembly housing further defining a first stress relief groove adjacent said first end stop and a second stress relief groove adjacent said second end stop.

30. A method for a dual end stop for a pneumatic actuator, said pneumatic actuator comprising an actuator housing, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing, said method comprising:

providing a stop assembly housing mountable to said actuator housing;

providing an aperture within said stop assembly housing for receiving said rotary drive;

providing a first groove along said aperture; and

providing a second groove along said aperture.

31. The method of claim 30, further comprising:

providing a first stop adjustment member with a first end for engaging a first stop surface,

providing a second stop adjustment member with a second end for engaging a second stop surface,

providing said first groove adjacent said first end, and

providing said second groove adjacent said second end.

32. The method of claim 31, further comprising:

providing that said first end has a concave surface, and

providing that said second end has a concave surface.

33. A dual end stop for a valve actuator, said valve actuator comprising an actuator housing, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing, a stop element having a first stop surface and a second stop surface, said dual end stop comprising:

a first stop member having a first end stop, said first end stop having a first tapering end which tapers to first end point, said first tapering end surface being engagable with said first stop surface for point contact to thereby stop said rotary drive element in a first rotational position; and

a second stop member having a second end stop, said second end stop having a second tapering end which tapers to a second end point, said second tapering end surface being engagable with said second stop surface for point contact to thereby stop said rotary drive element in a second rotational position.

34. The dual end stop of claim 33, further comprising:

said first tapering end having a first convex surface, and

said second tapering end having a second convex surface.

35. The dual end stop of claim 33, further comprising:

a stop assembly housing mountable to said actuator housing, said first stop member and said second stop member being mountable within said stop assembly housing.

36. The dual end stop of claim 34, further comprising:

said stop assembly housing defining a first groove adjacent said first end stop, and

said stop assembly housing defining a second groove adjacent said second end stop.

37. The dual end stop of claim 33, wherein said first stop member and said second stop member are mounted outside of said zone for pressure containment.

39. The method of claim 39, further comprising:

forming a first tapering end surface with a convex profile, and

forming said second tapering end surface with a convex profile.

40. The method of claim 38, further comprising:

providing a stop assembly housing mountable to said actuator housing, and

mounting said first stop member and said second stop member within said stop assembly housing.

41. The method of claim 39, further comprising:

mounting a bearing within said stop assembly housing for supporting said rotary drive element.

42. The dual end stop of claim 38, further comprising:

mounting said first stop member and said second stop member outside of said zone for pressure containment.

38. A method for a dual end stop for a valve actuator, said valve actuator having an actuator housing, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing, a stop element having a first stop surface and a second stop surface, said dual end stop comprising:

providing a first stop member with a first end stop having a first tapering end surface, said first tapering end surface being engagable with said first stop surface for stopping said rotary drive element in a first rotational position; and

providing a second stop member with a second end stop having a second tapering end surface, said second tapering end surface being engagable with said second stop surface for stopping said rotary drive element in a second rotational position.

43. A dual end stop adjustment for a rotary actuator, comprising:

an actuator housing for said pneumatic actuator, said actuator housing having a zone for pressure containment, a rotary drive element rotatably mounted within said actuator housing;

a stop element on said rotary drive element for rotation therewith, said stop element having a first stop surface and a second stop surface;

a first stop member for engaging said first stop surface;

a second stop member for engaging said second stop surface;

a first bearing for said rotary drive element for supporting a first end of said rotary drive element;

an outer bearing for said rotary drive element on an opposite side of said rotary drive element from said first end, said outer bearing being positioned adjacent said stop element; and

an inner bearing for said rotary drive element adjacent said stop element on an opposite side of said stop element with respect to said outer bearing.

44. The dual end stop adjustment of claim 43, further comprising:

a stop assembly housing, said first stop member and said second stop member being mounted within said stop assembly housing.

45. The dual end stop adjustment of claim 44, further comprising:

said actuator housing defining a recess, and

stop assembly housing being positioned in said recess.

46. The dual end stop adjustment of claim 43, further comprising:

a stop assembly housing, said outer bearing being mounted in said stop assembly housing.

47. The dual end stop adjustment of claim 43, further comprising:

a first convex end for said first stop member, and

a second convex end for said second stop member.

49. The method of claim 48, further comprising:

providing a stop assembly housing, and mounting said first stop member and said second stop member within said stop assembly housing.

50. The method of claim 49, further comprising:

forming a recess in said actuator housing, and

mounting said stop assembly housing within said recess.

51. The method of claim 48, further comprising:

mounting a stop assembly housing to said actuator housing, and

mounting said outer bearing being in said stop assembly housing.

52. The method of claim 43, further comprising:

providing said first stop member with a first convex end for engaging said first stop surface, and

providing said second stop member with a second convex end for engaging said second stop surface.

48. A method for a dual end stop adjustment for a rotary actuator, comprising:

providing an actuator housing for said pneumatic actuator;

providing a rotary drive element rotatably mounted within said actuator housing;

providing a stop element on said rotary drive element for rotation therewith, said stop element having a first stop surface and a second stop surface;

providing a first stop member for engaging said first stop surface;

providing a second stop member for engaging said second stop surface;

installing a first bearing for said rotary drive element for supporting a first end of said rotary drive element;

installing an outer bearing for said rotary drive element on an opposite side of said rotary drive element from said first end such that said outer bearing is positioned adjacent said stop element; and

installing an inner bearing for said rotary drive element adjacent said stop element on an opposite side of said stop element with respect to said outer bearing.

53. A dual end stop adjustment for a rotary actuator, comprising:

an actuator housing for said pneumatic actuator, a rotary drive element rotatably mounted within said actuator housing;

a stop element on said rotary drive element for rotation therewith, said stop element having a first stop surface and a second stop surface;

a first elongate stop member, said first elongate stop member being threaded so as to be moveable along an axis thereof for adjustably engaging said first stop surface, said first elongate stop member having a first end for engaging said first stop surface;

said rotary actuator defining a first threaded elongate aperture for receiving said first elongate stop member, said first threaded aperture having a first outer opening for receiving said first elongate stop member, said first threaded elongate aperture having a first length of threaded surface such that at least eighty percent of said first elongate member between said first outer opening of said first threaded aperture and said first end is threadably supported by said first length of threaded surface;

a second elongate stop member, said second elongate stop member being threaded so as to be moveable along an axis thereof for adjustably engaging said second stop surface, said second elongate stop member having a second end for engaging said second stop surface; and

said rotary actuator defining a second threaded elongate aperture for receiving said second elongate stop member, said second threaded aperture having a second outer opening for receiving said second elongate stop member, said second threaded elongate aperture having a second length of threaded surface such that at least eighty percent of said second elongate member between said second outer opening of said second threaded aperture and said second end is threadably supported by said second length of threaded surface.

54. The dual end stop adjustment of claim 53, further comprising:

said actuator housing having a zone for pressure containment,

said first elongate stop member being positioned outside of said zone for pressure containment, and

said second elongate stop member being positioned outside of said zone for pressure containment.

55. The dual end stop adjustment of claim 53, further comprising:

said first end having a first convex surface, and

said second end having a second convex surface.

56. The dual end stop adjustment of claim 53, further comprising:

a first external lock nut for locking said first elongate stop member in position, and

a second external lock nut for locking said second elongate stop member in position.

57. The dual stop adjustment of claim 53, further comprising:

a first lock screw mounted within said first threaded surface for locking said first elongate stop member in position, and

a second lock screw mounted within said second threaded surface for locking said second elongate stop member in position.

58. The dual end stop adjustment of claim 53, further comprising:

a stop assembly housing mounted to said actuator housing,

said first threaded elongate aperture being formed in said stop assembly housing, and

said second threaded elongate aperture being formed in said stop assembly housing.

60. The method of claim 59, further comprising:

providing said actuator with an actuator housing having a zone for pressure containment,

mounting said first elongate stop member outside of said zone for pressure containment, and

mounting said second elongate stop member outside of said zone for pressure containment.

61. The method of claim 59, further comprising:

providing said first end with a first convex surface, and

providing said second end with a second convex surface.

62. The method of claim 59, further comprising:

providing a first external lock nut for locking said first elongate stop member in position, and

providing a second external lock nut for locking said second elongate stop member in position.

63. The method of claim 59, further comprising:

mounting a stop assembly housing to said actuator housing,

forming said first threaded elongate aperture in said stop assembly housing, and

forming said second threaded elongate aperture in said stop assembly housing.

59. A method for a dual end stop adjustment for a rotary actuator, comprising:

mounting a rotary drive shaft within said rotary actuator;

providing said rotary drive shaft with a stop element for rotation therewith;

providing said stop element to have a first stop surface and a second stop surface;

providing a first elongate stop member such that said first elongate stop member is threaded so as to be moveable along an axis thereof for adjustably engaging said first stop surface, said first elongate stop member having a first end for engaging said first stop surface;

providing said rotary actuator with a first threaded elongate aperture for receiving said first elongate stop member, said first threaded aperture having a first outer opening, providing said first threaded elongate aperture with a length of threaded surface such that at least eighty percent of a portion of said first elongate member which extends from said first outer opening to said first end is threadably supported by said length of threaded surface;

providing a second elongate stop member such that said second elongate stop member is threaded so as to be moveable along an axis thereof for adjustably engaging said second stop surface, said second elongate stop member having a second end for engaging said second stop surface; and

providing said rotary actuator with a second threaded elongate aperture for receiving said second elongate stop member, said second threaded aperture having a second outer opening, providing said second threaded elongate aperture with a length of threaded surface such that at least eighty percent of a portion of said second elongate member which extends from said second outer opening to said second end is threadably supported by said length of threaded surface.

64. A rotary valve actuator, comprising:

an actuator housing, said actuator housing defining a recess;

a rotary actuator shaft mounted for rotation within said actuator housing;

an adaptor plate mounted within said recess of said actuator housing such that said adaptor plate fits tightly within said recess, said adaptor plate defining an aperture for receiving said rotary actuator shaft.

65. The rotary valve actuator of claim 64, wherein:

said recess and said adaptor plate is machined to a close tolerance to thereby prevent lateral movement of said adaptor plate within said recess.

66. The rotary valve actuator of claim 64, further comprising:

no more than two fasteners for securing said adaptor plate within said recess.

67. The rotary valve actuator of claim 64, further comprising:

one or more stop elements mounted within said adaptor plate.

68. An adaptor plate for a pneumatic actuator, said pneumatic actuator comprising an actuator housing with a pressurized zone, an actuator shaft mounted within said pneumatic actuator, said adaptor plate comprising:

first and second stop adjustment members mounted within said adaptor plate, said adaptor plate defining an aperture for receiving said actuator shaft, first and second stop surfaces for engagement with said first and second stop adjustment members, respectfully, said adaptor plate being mounted to said actuator housing outside of said pressurized zone.

69. A dual end stop adjustment for a rotary actuator, comprising:

an actuator housing for said pneumatic actuator, a rotary drive element rotatably mounted within said actuator housing;

a stop element on said rotary drive element for rotation therewith, said stop element having a first stop surface and a second stop surface;

a first elongate stop member, said first elongate stop member being threaded so as to be moveable along an axis thereof for adjustably engaging said first stop surface, said first elongate stop member having a first end for engaging said first stop surface;

said rotary actuator defining a first threaded elongate aperture for receiving said first elongate stop member;

a first threaded lock screw mounted within said first threaded surface for locking said first elongate stop member in position;

a second elongate stop member, said second elongate stop member being threaded so as to be moveable along an axis thereof for adjustably engaging said second stop surface, said second elongate stop member having a second end for engaging said second stop surface; and

said rotary actuator defining a second threaded elongate aperture for receiving said second elongate stop member; and

a second lock screw mounted within said second threaded surface for locking said second elongate stop member in position.