Cam apparatus for use with valves

Patent metadata

Field	Value
Publication number	US-9581228-B2
Application number	US-201414506233-A
Country	US
Kind code	B2
Filing date	Oct 3, 2014
Priority date	Oct 3, 2014
Publication date	Feb 28, 2017
Grant date	Feb 28, 2017

Abstract

Cam apparatus for use with valves are disclosed. An example apparatus includes a cam having a cam surface to engage a valve stem, a first portion of the cam surface to engage the valve stem in a closed position, a second portion of the cam surface to engage the valve stem in an open position, and a third portion of the cam surface adjacent the first portion and defining a curved profile. The third portion is to engage the valve stem when the cam is rotated to a first intermediate position between the closed position and the open position. The example apparatus also includes a fourth portion of the cam surface between the second portion and the third portion and defining a linear profile. The fourth portion is to engage the valve stem surface as the cam rotates between the first intermediate position and the open position.

First claim

What is claimed is:

1. An apparatus comprising:
a cam having a cam surface to engage a valve stem;
a first portion of the cam surface to engage the valve stem in a closed position;
a second portion of the cam surface to engage the valve stem in an open position;
a third portion of the cam surface adjacent the first portion and defining a curved profile, the third portion to engage the valve stem when the cam is rotated to a first intermediate position between the closed position and the open position; and
a fourth portion of the cam surface between the second portion and the third portion and defining a linear profile, the fourth portion to engage the valve stem as the cam rotates between the first intermediate position and the open position, the fourth portion and the second portion form an angle of about 172 degrees to enable the curved profile of the third portion to have a radius of curvature that accelerates an angular rotation of the cam as the cam rotates to the closed position to overcome resistive forces.

2. The apparatus of claim 1 , wherein the second portion defines a linear profile, the linear profile of the second portion being non-parallel to the linear profile of the fourth portion.

3. The apparatus of claim 2 , further including an edge positioned between the second portion and fourth portion, the edge prevents jamming of the cam by enabling the second portion to disengage from the valve stem to enable the cam to rotate from the open position.

4. The apparatus of claim 1 , wherein the cam surface is to engage the valve stem to cause the valve stem to move along a rectilinear path when the cam rotates.

5. The apparatus of claim 1 , wherein the curved profile of the third portion is to cause the valve stem to accelerate along a rectilinear path as the cam rotates between the open first portion and the closed portion.

6. The apparatus of claim 1 , wherein the angle and the radius of curvature enable a contact surface between the cam and the valve stem to be spaced apart from an axis of rotation of the cam by a distance at the first intermediate position to further accelerate the angular rotation of the cam as the cam rotates to the closed position to overcome the resistive forces.

7. An apparatus comprising:
a valve body defining a chamber and a gland;
a stem extending into the chamber of the valve body;
a shaft disposed in the gland of the valve body such that a seal is formed between the shaft and the gland, the shaft having an end that extends into the chamber of the valve body adjacent the stem; and
a cam coupled to the end of the shaft and defining an outer surface to engage an end of the stem, the outer surface having a first portion to engage the end of the stem in a closed position, a second portion to engage the end of the stem in an open position, a third portion adjacent the first portion and defining a curved profile that is to engage the end of the stem in a first intermediate position, a fourth portion between the second portion and the third portion and defining a linear profile that is to engage the end of the stem in a second intermediate position, the fourth portion and the second portion form an angle of about 172 degrees to enable the curved profile of the third portion to have a radius of curvature that accelerates an angular rotation of the cam as the cam rotates to the closed position to overcome resistive forces resulting from the seal.

8. The apparatus of claim 7 , further including a cap to couple the cam to the end of the shaft.

9. The apparatus of claim 7 , further including a poppet coupled to the stem that is to sealingly engage the valve body when the cam is in the closed position.

10. The apparatus of claim 7 , further including a biasing member disposed in the chamber of the valve body, the biasing member compresses as the stem moves from the closed position to the open position.

11. The apparatus of claim 7 , wherein the cam is rotated about 70 degrees relative to the closed position to cause the cam to be positioned in the open position.

12. The apparatus of claim 11 , wherein the cam causes the stem to move at least 0.36 inches to compress a biasing member within the chamber as the cam rotates from the closed position to the open position, the biasing member to provide a force of at least 38 pounds when the cam is in the open position to urge the cam to rotate from the open position.

13. The apparatus of claim 7 , wherein the cam is rotated about 17.5 degrees relative to the closed position when the cam is in the first intermediate position, the cam to cause the stem to compress a biasing member in the chamber when the cam is in the first intermediate position.

14. The apparatus of claim 13 , wherein, to enable the cam to rotate to the closed position, the biasing member provides at least 16 pounds of force in the first intermediate position to overcome resistance resulting from the seal formed between the shaft and the gland.

15. The apparatus of claim 13 , wherein, to enable the cam to rotate to the closed position, the stem applies at least 7 inch-pounds of torque to the cam in the first intermediate position to overcome resistance resulting from the seal formed between the shaft and the gland.

16. The apparatus of claim 7 , wherein an axis of rotation of the cam is spaced apart from a longitudinal axis of the stem, the angle and the radius of curvature enable the cam to remain engaged to the end of the stem as the cam rotates about the axis of rotation between the first intermediate position and the open position.

17. The apparatus of claim 16 , wherein the angle and the radius of curvature enable the cam to engage the end of the stem along the longitudinal axis at the first intermediate position, a distance between the axis of rotation of the cam and the longitudinal axis of the stem to enable the stem to apply at least 7 inch-pounds of torque to the cam in the first intermediate position to enable the came to overcome the resistive forces resulting from the seal.

18. An apparatus comprising:
means for transforming rotary motion of a shaft to linear motion of a stem, the means for transforming coupled to the shaft and to engage the stem to transform the rotary motion to linear motion, the means for transforming defining:
means to engage the stem in a closed position;
means to engage the stem in an open position;
means to engage the stem in a first intermediate position as the means for transforming rotates between the closed position and the open position, the means to engage the stem in the first intermediate position defining a curved profile and being adjacent the means to engage the stem in the closed position; and
means to engage the stem in a second intermediate position as the means for transforming rotates between the first intermediate position and the open position, the means to engage the stem in the second intermediate position defining a linear profile and being positioned between the means to engage the stem in the open position and the means to engage the stem in the closed position, the means to engage the stem in the second intermediate position and the means to engage the stem in the open position form an angle of about 172 degrees to enable the means to engage the stem in the first intermediate position to accelerate an angular rotation of the means for transforming to overcome resistive forces as the means for transforming rotates to the closed position.

19. The apparatus of claim 18 , wherein the means to engage the stem in the second intermediate position ena

Assignees

• Emerson Process Man Regulator Technologies Inc

Inventors

• Nashery Khashayar Afnan
• Vasquez Ernesto

Classifications

• F16K31/524 Primary

  with a cam · CPC title

• F16K1/34

  Cutting-off parts, e.g. valve members, seats (F16K1/06, F16K1/12, F16K1/14, F16K1/26 take precedence) · CPC title

• F16K3/205

  by means of cams · CPC title

• F16K31/52

  with crank, eccentric, or cam · CPC title

• F16K31/523

  comprising a sliding valve · CPC title