Abstract:
An improved power actuated valve, particularly a ball valve, which can be manually opened or closed quickly, in the event of failure of power operation, by manual turning force applied directly to the control stem of the valve without the necessity to overcome any drag or negative torque imposed by the power operating mechanism and speed reducing transmission.

Description:
This application claims priority from Provisional Patent Application No. 60/771,690 filed Feb. 9, 2006. 

   FIELD OF THE INVENTION 
   The present invention relates to power actuated valves which generally incorporate an actuator or a motor operating a speed-reducing transmission to turn a flow control member within a valve between an open and closed positions. More specifically, the invention relates to a declutching mechanism for facilitating manual operation of a power actuated valve. 
   BACKGROUND OF THE INVENTION 
   Power actuated valves of this general character afford many advantages, particularly in conjunction with remotely control operating systems. Characteristically, such valves are most reliable, nevertheless, operational failures can occur due to power failures or an occasional malfunction of the power driving mechanism or associated controls. 
   When normal power operation of such a power actuated valve is impossible on account of a power failure or otherwise, it is desirable and even essential that the valve be operated either to start or stop a flow of fluid through the valve. As an emergency procedure, such valves have been operated manually either by turning the driving motor or by turning the output end of the power drive connected with the valve control stem. Neither of these options has been satisfactory and have, on occasion, been ineffective and even a cause of damage to the mechanism. 
   On account of the wide difference between the rather limited output torque of the driving motor which is practical to use in such valves and the comparatively large torque required to turn the flow control member in the valve, particularly in the case of ball valves, it is highly advantageous to connect the driving motor to the flow control member by means of a transmission having a very high torque multiplying capability and incidentally correspondingly high speed reducing capabilities. 
   Consequently, the option of manually turning the driving motor or input end of the torque multiplying and speed-reducing transmission is necessarily a slow process because of the many turns required. Moreover, the torque manually applied to the driving motor end of the transmission and being possibly much higher than the maximum torque output of the driving motor is multiplied by the speed-reducing transmission with the consequence that the valve or its operating mechanism can be rather easily damaged by such manual operation. 
   On the other hand, manually turning the output end of the driving mechanism connected to the valve control shaft can be difficult and ineffective or even impossible as a practical matter. For example, the torsional drag of electrical brushes associated with an electric driving motor can, when multiplied through the speed-reducing transmission, impose a strong negative torque or braking effect resistant to turning of the output end of the drive connected to the valve control stem. As a practical matter, the cumulative drag of this negative torque of the unenergized drive mechanism and the normal turning resistance of the flow control member within the valve can make it unfeasible to manually open or close the valve by torque manually applied to the output end of the actuating mechanism. 
   SUMMARY OF THE INVENTION 
   Wherefore, it is an object of the present invention to overcome the above mentioned shortcomings and drawbacks associated with the prior art. 
   An object of the present invention is to provide an improved power actuated valve, particularly a ball valve, which can be manually opened or closed quickly, in the event of failure of power operation, by manual turning force applied directly to the control stem of the valve without the necessity to overcome any drag or negative torque imposed by the power operating mechanism and speed reducing transmission. 
   Another object is to provide power actuated valve structure of a compact character which can be operated manually by activating a disengagement or declutching mechanism which disengages the power operating mechanism and the transmission from the output driving the valve control stem and being selectively operable to free the valve stem for manual rotation without drag from the power driving mechanism or speed reducing transmission. 
   Yet another object of the present invention is to provide a power actuated valve in which selective operation of the valve either by power through a power drive or manually by means of a handle, wheel or the like with the power drive disconnected from the output is provided by a spring biased declutching mechanism operated by a manually engaged button positioned on or near the handle. 
   A still further object of the present invention is to provide the declutching mechanism with an output gear which connects to the transmission, and the output gear is decoupled from the actuator output shaft so that any drag associated with the transmission and power operating mechanism is eliminated during turning of the valve stem manually by means of the handle, lever, wheel or the like. 
   A further object is to provide power actuated valve control means which facilitates direct manual turning of the valve control stem by means of a handle, lever, wheel or wrench without drag from the power operating mechanism and which has a most rugged and reliable construction which is well adapted for economical manufacture. 
   The present invention also relates to a declutching mechanism for disengaging a valve actuator drive input from a valve, the declutching mechanism having a manual input for initiating operation of the declutching mechanism, an axially movable spring biased operating rod, a radially motivated clutch block; and a drive gear being demountably coupled to an output of the valve actuator mechanism by the radially motivated clutch block. 
   The present invention also relates to a method for disengaging a valve actuator drive input from a valve by use of a declutching mechanism, the method having the steps of manually initiating operation of the declutching mechanism, axially moving a spring biased operating rod, radially motivating a clutch block, and demountably coupling a drive gear to an output of the valve actuator mechanism via the radially motivated clutch block. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is diagrammatic representation of an actuator valve; 
       FIG. 2  is a partial view of an override mechanism of the presently claimed invention; 
       FIG. 3  is a perspective view of a handle and disengagement button; 
       FIG. 4  is a cross section view of the handle and disengagement button; 
       FIGS. 5   a ,  5   b  are axial and radial cross sectional views, respectively, of the declutching mechanism in an engagement position; 
       FIGS. 6   a ,  6   b  are axial and radial cross sectional views, respectively, of the declutching mechanism in a disengaged position; and 
       FIGS. 7   a ,  7   b  are axial and radial cross sectional views, respectively, of the declutching mechanism in a disengaged position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The primary components of the manual override mechanism for an automated valve as depicted in  FIG. 1  of the drawings will now be described in detail relative to the function of the automated valve. It is well known in the art to automate the opening and closing of a valve, for example a ball valve  1  via an electronic, pneumatic or hydraulically driven actuator  5  as diagrammatically shown in  FIG. 1 . The actuator  5  drives a reducing transmission, gear or gear train  7 , also diagrammatically shown, which turns an actuator output shaft  9  connected to a ball  2  of the ball valve  1  to impart rotation thereto according to a relative signal applied to the actuator  5 , e.g., a signal telling the actuator to either open or close the valve to some relative degree. 
   In general, because of the potential for failure of such automated systems, e.g., the loss of electric power to an electric motor driven actuator, such automated valves are very often supplied with a means of manual operation like a handle  13 , wheel or even a nut for engagement by a wrench, which can be manually turned in order to turn the output shaft  9  and open and/or close the valve in the event of a power failure or failure of the actuator. As the specifics of the above noted actuators drives and types of valves which could be utilized with the below described manual override mechanism are numerous and well known in the art, no further description regarding such actuator drives and valves is provided. 
   A description of the override or declutching mechanism of the present invention as shown in  FIG. 2  is now provided. The hollow shaft  9  defines a passage  11  extending along an axis A between the handle  13  fixedly attached to a first end  12  of the shaft  9 , and a second end  17  of the shaft  9  having an output coupling  19  with the valve  1  (not shown), e.g., the valve stem of the exemplary ball valve for actually rotating the ball is connected via an output coupling  19  to the second output end  17  of the shaft  9 . Disengageably affixed to an intermediate portion  35 ′ of the shaft  9  between the handle  13  and the ball valve  1 , is an output gear  20  which is driven by the actuator  5  for driving rotation of the shaft  9  and hence the ball valve  1 . The output gear  20  is, however, fully disengageable from rotation with the output shaft  9  through a declutching mechanism  31 , to be discussed in further detail below. It is also to be appreciated that the output gear  20 , associated declutching mechanism  31  and the relative connection with the actuator  5  could be positioned at any point along the shaft  9  besides that of intermediate or in-between the valve handle  13  and the output coupling  19 . 
   Also attached to the first end  12  of the shaft  9  and positioned relative to the handle  13  is a gear train disengagement button  33 . The disengagement button  33  is axially moveable along axis A relative to the shaft  9  and the handle  13  to motivate a connected override operating rod  35  which passes through the passage  11  of the hollow shaft  9  and along the axis A. When the disengagement button  33  is actuated, the operating rod  35  is moved axially along the axis A relative to the shaft  9  and operates the declutching mechanism  31  to disengage the output gear  20  from the shaft  9 . A further description of the structure and function of the operating rod  35  and associated declutching mechanism  31  will be provided below. 
   Also attached to the shaft  9  is, for example, a limit switch operating cam  25  for defining the open and closed positions of the valve  1  via an associated electromechanical switch  26 . It is to be appreciated that the switch operating cam  25  as displayed in  FIG. 2  is fixedly attached so as to rotate with the shaft  9  and operate the limit electromechanical switch  26  so as to provide an electric motor  27  with a signal in accordance with the rotational position of the shaft  9 . By way of example, as shown, a first cam  25  and associated switch  26  could indicate one of an open or a closed position of the valve  1 , and a second cam  25 ′ and second switch  26 ′ could also be used to further indicate the other of the open or closed position. As other electromechanical position indicators and sensors could also be used to provide the rotational position of the valve  1  and associated components of the actuator to the motor  27 , no further discussion is provided. 
   As shown in  FIG. 3 , the components described above are substantially enclosed by an actuator enclosure cover  4  having a detachable base  3  secured thereto by a number of bolts as shown in  FIG. 3  of the drawings. The second output end  17  of the shaft  9  connects through the base  3  with the output coupling  19  (not shown in this view), which is, in turn, connected to the ball of the ball valve  1  as described above. Extending through the top of the cover  4 , the first end  12  of the shaft  9  which supports the disengagement button  33  is also connected to the manual override handle  13  for operation of the shaft  9  in conjunction with the disengagement button  33 , when necessary. 
   The override handle  13  has a support portion  14  which is keyed in such a manner so as to be removably fixed to the shaft  9  so that rotation of the support portion  14  results is a corresponding rotation of the shaft  9 . Attached to a first end of the support portion  14  is an extendable handle cover  15  which works in conjunction with the support portion  14  to make it easier for an operator to turn the shaft  9  into a desired position. The handle cover  15  is rotatably fixed to the first end of the support portion  14  so that the handle cover  15  can be rotated through about a  180  degree rotation from a closed position where the handle cover  15  is folded and substantially overlays the support portion  14  and the disengagement button  33  as shown in  FIG. 2 , and a second position shown in  FIG. 3 , where the handle cover  15  is rotated about the first end of the support portion  14  to extend substantially longitudinally with the support portion  14  and thus form a longer, extended handle  15  providing more torque for manually turning the shaft  9 . 
   The handle cover  15  is rotatably fixed to the support portion  14  on the first end with a pin or axle  21  which allows about 180 degrees of rotation of the handle cover  15  about the pin or axle  21  along an axis C relative to the support portion  14 . In the first or closed position in  FIG. 2 , the cover  15  is folded over the support portion  14  and secured at a free end through holes  15 ′ by the latching engagement buttons  18  fixed to the support portion  14  via a cover release spring body  16  extending into corresponding detents or holes in both the support portion  14  as well as the free end of the cover  15 . 
   To open the handle  13  into the extended open position the latching engagement buttons  18  are engaged by a user, the cover release spring  17  is compressed to force the buttons out of holes  15 ′, and the free end of the cover  15  is released to be used as an extension to the support portion  14  in the open position. To again close the handle  13 , the user pushes the cover  15  at the free end rotating the cover  15  about the pin or axle  21 . As the cover  15  folds over the support portion  14 , the edges of the cover  15  press the cover release buttons  18  inwards which, in turn, compress the cover release spring  17 . When the holes  15 ′ on the side of the cover  15  become aligned with the holes buttons  18  in the support portion  14 , the cover release buttons  18  are forced through the holes  15 ′ on the side of the cover  15  by the force of the compressed cover release spring  17 , and the cover  15  is again locked into the closed position. 
   Turning to  FIG. 4 , the support portion  14  of the handle  13  is attached to the shaft  9  via a keyed hole  24  with two flat sides allowing no or minimal rotation between the override handle  13  and shaft  9 . Thus, as the handle  13  rotates in either a clockwise or counter-clockwise direction so does the shaft  9 . A retaining nut  26  secures the support portion  14  of the override handle  13  to the shaft  9  when fastened over the override operating rod  35  and threaded to the first end of the shaft  9 . When the retaining nut  26  is in place, the disengagement button  33 , which is interlocked with the retaining nut  26 , is in contact with the override operating rod  35 . The retaining nut  26  limits the upward motion of the gear-train disengagement button  33  via an inwardly protruding edge  28  which catches an outwardly protruding edge  29  on the button  33  which, in turn, also limits the downward motion of the override operating rod  35 . 
   Turning now to  FIG. 5   a , at the opposing end of the operating rod  35 , which extends through a passage  11  defined by the shaft  9 , is an override return spring  8  biasly engaging the operating rod  35  on a bottom surface and forcing the operating rod  35 , and hence the disengagement button  33 , upwards relatively towards the handle  13 . Approximately ¾ length down the operating rod  35 , there is formed a protruding ring  36 , the top edge of which limits the upward range of motion of the override operating rod  35  against a matching indentation  37  in the passage wall defined by the output shaft  9 . The bottom-side of the protruding ring  36  forms a concave lip, resulting in a operating rod intermediate section  35 ′ having a diameter or portion formed smaller than the main operating rod section  35  above the protruding ring  36 . This smaller intermediate section  35 ′ of the override operating rod  35  is essential to the manual operation of the declutching device because when the operating rod  35  is pushed down against the spring  8 , a space  39  allows the cylindrical clutch dogs  32 , discussed in further detail below, to move inward into the space  39  defined by intermediate section  35 ′ releasing the connection between the shaft  9  and output gear  20 . Below the intermediate section  35 ′, a slope section changes the smaller intermediate section  35 ′ back to a larger diameter. 
   The shaft  9  encompassing the operating rod  35  is a hollow shaft which extends the entire length of the device from the handle  13  to the output coupling  19  and transfers the rotational force, either from the motor  27  or the override handle  13  to the output coupling  19 . The hollow shaft  9  defines the passage  11  in which the operating rod  35  is axially biased. At the location on the shaft  9  where the output gear  20  is located, there are two small radial passages or holes  10  formed on opposite sides of the shaft  9 . A pair of cylindrical clutch dogs  32 , one for each radial passage or hole  10  and loosely positioned for radial movement relative to the shaft  9  and operating rod  35  are incorporated therewith. The radial position of the clutch dogs  32  depends on the position of the override operating rod  35  as will be discussed in greater detail below 
   Turning now to  FIG. 5   b , the output gear  20  is the last gear in the gear train  7  (not shown) driven by, for example, the electric motor  27  to drive the normal, i.e., electromechanical, opening and closing operations of the valve  1 . The clutch dogs  32 , the passages  10  and the output gear  20  are all part of the declutching mechanism  31  for engaging and disengaging the output gear  20  from the output shaft  9 . The output gear  20  has an inner bore  22  having a pair of opposing notches  23  depicted in  FIGS. 5-7  which may be further defined by a hardened bore ring  30  including the pair of opposing notches  23 . The declutching mechanism  31  connects the output gear  20  to the shaft  9  when the cylindrical clutch dogs  32  are pushed through the respective radial passages  10  in the output shaft  9  by the operating rod  35  and interlocked in the notches of the output gear  20  as shown in  FIGS. 5   a ,  5   b.    
   To disconnect the output gear  20  from the output shaft  9  to facilitate manual operation of the valve, the disengagement button  33  is pushed, thus also pushing the operating rod  35  downwards against the bias of spring  8  and, as seen in  FIGS. 6   a  and  6   b , the sufficient space  39  is created in the passage  11  between the smaller diameter intermediate section of the operating rod  35  and the inner wall of the output shaft  9  to permit the clutch dogs  32  to be retracted therein. Thus, when the shaft  9  is rotated by an operator with the disengagement button  33  pushed, the output gear  20  is generally held back from correspondingly turning by the inherent drag of the actuator  5  and the gear train  7  and the corners of the notches  23  in the bore  21  the output gear  20  place an inward axial force on the cylindrical clutch dogs  32  forcing the clutch dogs  32  inward into the space  39  in the passage  11  of the output shaft  9 . Thus, with the clutch dogs  32  retracted, as shown in  FIG. 8 , the declutching mechanism  31  disengages the output gear  20  from the shaft  9  by pushing the cylindrical clutch dogs  32  into the radial passages  10  in the output shaft  9  when the gear train disengagement button  33  is pressed, and hence the output shaft  9  is free to rotate relative to the output gear  20 . 
   As shown in  FIGS. 5   a ,  5   b  of the drawings, when the output gear  20  is engaged (i.e., the gear train disengagement button  33  is not pressed), the cylindrical clutch dogs  32  are locked into the notches  23  of the declutching mechanism  31  and through the passages or holes  10  in the output shaft  9  by the override operating rod  35  in the center of the shaft  9 . In this position, the cylindrical clutch dogs  32  allow minimal slip between the output gear  20  and the shaft  9  and, therefore, allow the actuator  5  or any other device supplying rotational energy to the output gear  20  to control the rotation of the shaft  9 . 
   When the disengagement button  33  is engaged or pressed, as depicted in  FIGS. 6   a ,  6   b , the override operating rod  35  compresses the override return spring  8  and the smaller diameter intermediate section  35 ′ of the override operating rod  35  is motivated into position next to the clutch dogs  32 . In this position, the cylindrical clutch dogs  32  are no longer locked into the notches  23  in the output gear and are free to move inwardly into the space  39 . 
   As shown in  FIGS. 7   a ,  7   b , when the override handle  13  is rotated slightly while the disengagement button  33  is pressed, the output shaft  9  turns and the notches  23  of the output gear  20  push the clutch dogs  32  back through the holes  10  in the output shaft  9  and thus free the shaft  9  from the output gear  20 . Once the clutch dogs  32  have been pushed from the notches  23 , the gear train disengagement button  33  need no longer be pressed to operate the valve manually. The override handle  13  and output shaft  9  will rotate up to 180 degrees about the axis A in either the clockwise or counter-clockwise direction while opening and closing the ball valve  1  without any interference from the output gear  20 , gear train  7 , or drive motor  27 . 
   While the override handle  13  is rotating, the upward force created by the override return spring  8  is partially converted into an axial force by the angled slope  35 ″ of the override operating rod  35 . This axial force placed on the bottom edge of the cylindrical clutch dogs  32  causes them to rotate along the inner wall of the shaft  9  acting almost like a bearing. Once the override handle  13  has rotated  180  degrees, the holes  10  in the output shaft  9  become realigned with the opposite notches  23  in the output gear  20 . If the disengagement button  33  is not again pressed, the clutch dogs  32  are forced into the notches  23  by the upward force that the override return spring  8  places on the override operating rod  35 . Once the cylindrical clutch dogs  32  are forced into the notches  23  of the declutching mechanism  31 , the override return spring  8  forces the operating rod  35  upwards and the output gear  20  becomes re-engaged with the output shaft  9  and can again control its rotation. 
   Since certain changes may be made in the above described declutching mechanism, without departing from the spirit and scope of the invention herein involved, it is intended that all of the subject matter of the above description or shown in the accompanying drawings shall be interpreted merely as examples illustrating the inventive concept herein and shall not be construed as limiting the invention.