Abstract:
A visual position indicator has a stator and a rotor with angularly displaced eccentricities for engaging corresponding spring biased actuators with magnets. Depending on the rotor position relative to the stator, one or more of the actuators is moved to a position whereat the field of its respective magnet can operate a magnetic switch disposed in a hermetically sealed housing. A decoder connected to the switches can produce a signal indicative of rotor position.

Description:
This application claims priority under provisional U.S. Patent Application Ser. No. 60/104,561 filed Oct. 16, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     This invention relates to a position indicator for a rotary valve actuator which is used to open or close a rotary valve, e.g., the type of indicator which is the subject of U.S. Pat. No. 5,957,158. More specifically, the invention is directed to apparatus for providing a visual and electrical indication of whether or not a rotary valve is in an open, closed, or intermediate position. Electrical indication is provided by novel means employing cams to engage spring-biased rods having magnets for actuating one or more magnetic switches. 
     It is known to use pneumatic and hydraulic pressure to operate a rotary valve actuator by applying fluid under pressure to a valve actuator through pneumatic or hydraulic fluid lines. For example, there is known in the art a type of rotary valve actuator having opposing pistons which are coupled to a rack and pinion mechanism for converting pneumatic or hydraulic pressure applied to the pistons to torque for opening and closing a rotary valve. 
     The rotary valve has a valve member which is directly connected to the output shaft of the rotary actuator and is selectively rotated into and out of the path of fluid flow between the inlet and outlet ports of a valve housing, between open and closed positions which are typically ninety degrees apart. Although the open or closed state of a rotary valve may be indirectly determined by sensing fluid pressure or flow downstream of the valve, it is desirable to have a direct indication of whether a valve is open or closed, and its exact position, independently of fluid flow through the valve. A direct indication of the operating position of a rotary valve can be provided from a visual observation of the angular position of the output shaft on the rotary valve actuator relative to a fixed reference, since the output shaft of the rotary valve actuator is directly connected to the valve member. However, often it is desirable to determine valve position from a remote location whereat the valve is not visible. The use of electric sensors on a valve to determine position has heretofore been limited due to adverse environmental effects on sensor circuitry. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the aforementioned problems of the prior art in providing a visual indicator which includes a combination visual and electrical valve position indicator. More specifically the invention provides for a position indicator having a stator with a central axis and a base, a rotor coaxially rotatably mounted on the stator, the rotor having a circumference with a plurality of angularly displaced, vertically offset, eccentricities. The rotor is provided with a plurality of stacked rings, each having one or more eccentricities on its surface. Each of the rings has an upper edge and a lower edge, there being meshing teeth on the upper edge and lower edge for removably interlocking adjacent stacked rings to prevent relative angular motion between them. 
     Actuators in one to one correspondence with the eccentricities are independently movably mounted relative to the base. Each one of the actuators has a cam surface engageable by a corresponding one of the eccentricities for moving the actuator to an active position when the rotor rotates to a predetermined position. Restoring springs are mounted between the actuator and the base for restoring each actuator to a rest position when the rotor rotates away from the predetermined position. 
     A plurality of magnetic switches in one to one correspondence with the actuators are fixedly mounted relative to the base in a hermetically sealed housing, each of the magnetic switches having a first state, e.g., open, in the absence of a magnetic field and a second state, e.g., closed, in the presence of a magnetic field. A magnet is mounted on each of the actuators for producing a magnetic field about a corresponding one of the magnetic switches thereby causing the magnetic switches to be in the second state when the actuator is in its active position, the magnetic switches being free of the magnetic field and in the first state when the actuator is in its rest position. 
     A decoder can be connected to each of the magnetic switches for producing a signal indicative of the position of the rotor relative to the stator. 
     It is therefore an object of the invention to provide an electronic indication of valve actuator position which can signal numerous positions. 
     Another object of the invention is to be able to change the positions of a valve actuator which can be sensed without exposing electrical sensing circuitry to the ambient environment. 
     Still another object of the invention is to sense valve actuator position without any mechanical linkage between the valve actuator and the sensing electronics which can cause exposure of electrical sensing circuitry to the ambient environment. 
     A further object of the invention is provide valve actuator position indication signals which can be applied to computer systems. 
     Other and further objects of the invention will be apparent from the following drawings and description of a preferred embodiment of the invention in which like reference numerals are used to indicate like parts in the various views. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view an indicator assembly suitable for use in the preferred embodiment of the invention, in a closed position. 
     FIG. 2 is a perspective view of the indicator assembly of FIG. 1 in a disposition where the valve is open. 
     FIG. 3 is a perspective view of a stator component of the indicator assembly of FIG.  1 . 
     FIG. 4 is a top plan view of the stator of FIG.  3 . 
     FIG. 5 is a sectional elevation view of the stator taken through line  5 — 5  of FIG.  4 . 
     FIG. 6 is a right side elevation view of the stator of FIG.  3 . 
     FIG. 7 is a rear elevation view of the stator of FIG.  3 . 
     FIG. 8 is a bottom plan view of a stator of FIG.  3 . 
     FIG. 9 is a perspective view of a rotor of the indicator assembly of FIG. 1 
     FIG. 10 is a top plan view of the rotor of FIG.  9 . 
     FIG. 11 is a sectional elevation view of the rotor taken through line  11 — 11  of FIG.  10 . 
     FIG. 12 is a perspective view of the indicator assembly of FIG. 1, with a cover of the apparatus removed, in a disposition where the valve is closed. 
     FIG. 13 is a perspective view of the indicator assembly of FIG. 1, with the cover of the apparatus removed, in a disposition where the valve is open. 
     FIG. 14 is a top perspective view of the indicator assembly of FIG. 1 in a disposition where the valve is closed. 
     FIG. 15 is a top perspective view of the indicator assembly of FIG. 1 in a disposition where the valve is open. 
     FIG. 16 is a perspective view of the cover of the apparatus of the preferred embodiment of the invention. 
     FIG. 17 is a top plan view of the cover of FIG.  16 . 
     FIG. 18 is a side elevation view of the cover of FIG.  16 . 
     FIG. 19 is a rear elevation view of the cover of FIG.  16 . 
     FIG. 20 is a bottom plan view of the cover of FIG.  16 . 
     FIG. 21 is a sectional elevation view of a preferred embodiment of the invention; 
     FIG. 22A is a perspective view of a combined base and housing for the invention. 
     FIG. 22B is a bottom plan view of the combined base and housing of FIG.  22 A. 
     FIG. 23 is a perspective view of a rotor driver for the invention. 
     FIG. 24 is a perspective view of a rotor drive rod for the invention. 
     FIG. 25 is a perspective view of a cam ring for the invention. 
     FIG. 26 is a sectional elevation view of a sleeve for the invention. 
     FIG. 27 is a perspective view of an indicator assembly for the invention, similar to the indicator assembly of FIG.  1 . 
     FIG. 28 is a perspective view of a plunger assembly for the invention. 
     FIG. 29 is a perspective view of a leaf spring for the invention. 
     FIG. 30A is a top plan view of a switch assembly for the invention. 
     FIG. 30B is a side elevation view of the switch assembly of FIG.  30 A. 
     FIG. 31 is a schematic view of the switch assembly of FIG. 30A and a decoder to which the switch assembly is connected. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1 and 2 of the drawings, an indicator  1  has a stator  2 , a rotor  3 , and a cover  4 . 
     Referring additionally to FIGS. 3-8, the stator  2  has a circular base  21  with a central axis  17 . Upwardly extending from the circular base  21  are three equiangularly spaced arcuate walls or volutes  22 . Each stator volute  22  has a leading edge  18  and a trailing edge  20 . Each stator volute&#39;s leading edge  18  is radially displaced from the axis  17  by a distance greater than the distance of its trailing edge  20  from the axis  17 . On the outer surface of each of the stator volutes  22  along the base  21  of the stator  2  are three respective shoulders  23  from which index pointers  24  extend upwardly. 
     The apertures of the stator cover  4  and base  21  are part of a unique alignment system that allows the indicator  1  to be adjusted to allow for any misalignment of the output shaft on the rotary valve actuator that drives the indicator  1 . Shaft misalignment on the rotary valve actuator is a result of dimensional variations within production or operating tolerances. 
     Referring now to FIGS. 9-11, the rotor  3  has a hub  31  in the form of a central hollow cylinder with an axial bore  32 , having straight parallel sides  33  connected by arcuate sections  34 , for receiving a keyed drive shaft. The hub  31  is surrounded by a circular concentric wall  35 . The hub  31  and concentric wall  35  are connected by two intermediate diametrically opposite webs  36  extending from the outer surface of the hub  31  to the inner surface of the concentric wall  35 . The webs  36  are diametrically oppositely disposed with respect to the axis  32  of the rotor  3 . 
     Connected to and extending from the outer wall of the concentric wall  35  are three equiangularly disposed arcuate walls or volutes  37 . Each of the rotor volutes  37  extends radially from the outer surface of the concentric wall  35  and sharply turns inwardly so that the major length of each rotor volute is disposed along an arc approximately concentric with the axis  32  of the rotor  3 . The extended length of the overlapping volutes  37  relative to the angular distance between them also serves to reduce stress upon them. 
     Each rotor volute  37  has a leading edge  30  and a trailing edge  39 , the latter being at the intersection of each rotor volute  37  with the concentric wall  35 . Each rotor leading edge  30  is radially displaced from the axis  32  by a distance greater than the distance of the trailing edge  39  from the axis  32 . The rotor  3  is coaxially rotatably mounted on the stator for relative rotation between a closed position corresponding to the closed position of the output shaft on the rotary valve actuator and an open position corresponding to the open position of the output shaft on the rotary valve actuator. When so mounted, each rotor volute corresponds to one of the stator volutes  22  and has its leading edge  30  radially displaced from the axes  17 ,  32  by a distance less than the radial displacement of the leading edge  18  of its corresponding stator volute  22  from the axes  17 ,  32  and greater than the radial displacement of the trailing edge  20  of another stator volute  22 , proximate to the leading edge  18  of the corresponding stator volute  22 , from the axes  17 ,  32 . The leading edge of each of the rotor volutes  37  is in radial alignment with a portion of its corresponding stator volute  22  when the rotor is in the closed position for hiding the rotor volute. 
     Referring now to FIGS. 12 and 13, the volutes  22  of the stator  2  and rotor  3  are positioned relative to one another so that when the rotor  3  is mounted on the stator  2 , the rotor  3  can be rotated relative to the stator  2  between one position (FIG. 12) wherein each of the three volutes  37  of the rotor  3  is hidden behind a corresponding one of the three volutes  22  of the stator  2  and another position (FIG. 13) whereat the rotor volutes  37  are exposed. 
     The leading edge of each of the rotor volutes  37  is in radial alignment with a portion of its corresponding stator volute  22  when the rotor is in the closed position for hiding the rotor volute when viewed from a point external to the indicator along a radial line of sight to the axis  32  when the rotor is in the open position. The leading edge of each of the rotor volutes  37  extends circumferentially beyond the leading edge of its corresponding stator volute  22  for exposing the rotor volute when viewed from a point external to the indicator along a radial line of sight to the axis  32  when the rotor is in the open position. As the rotor  3  is rotated relative to the stator  2 , each of the volutes  37  of the rotor  3  extends beyond an end of its corresponding stator volute  22  whereby it is visible from the exterior of the indicator  1 . 
     The degree of extension of the rotor volutes  37  beyond the leading edges  18  of their corresponding stator volutes  22  is an indicator of the degree of rotation of the output shaft on the rotary valve actuator to open the valve, and can be measured by observing its penetration into zones  38  between the index pointers  24 . 
     Index pointers  24  define four zones  38 , three between adjacent pairs of index pointers  24 , and one between a first index pointer  24  and the edge of an adjacent stator volute  22 . The degree of rotation of the rotor  3  can be easily determined by observing the penetration of each of the rotor volutes  37  into the regions defined by the index pointers  24 . In the preferred embodiment of the invention, the rotor  3  and stator  2  are of contrasting colors. The index pointers  24  are part of, and preferably the same color as, the stator  2  and, therefore, contrast with the volutes  37  of the rotor  3  as they extend from beyond the volutes  22  of the stator  2 . 
     Referring again to FIG. 4 of the drawings, the base  21  has a central opening  27  in the shape of a double key hole with a central circular area  28  and diametrically opposed windows  29 . As can best be seen in FIGS. 14 and 15, depending on the relative position of the rotor  3  with respect to the stator  2 , the web  36  between the rotor hub  31  and the concentric wall  35  has an angular width and is positioned on the rotor  3  such that when the rotor  3  has its volutes  37  completely hidden by the volutes  22  of a stator  2 , i.e., corresponding to the closed position of the valve actuator (FIG.  14 ), the webs  36  are out of registration with the keyhole central opening  27  in the base  21  and not visible. When the rotor  3  is rotated to a position whereat the rotor volutes  37  are maximumly extended from behind the stator volutes  22 , the webs  36  are in registration with the openings in the stator base  21  and, therefore, visible through the base  21  (FIG.  15 ). The webs  36 , being parts of the rotor  3  and of the same color as the rotor  3 , are strikingly visible due to their contrast with the color of the stator base  21 . 
     Referring now to FIGS. 16-20, the cover  4  is congruent to the stator base  21  and is mounted over the free edges  28  of the arcuate walls forming the stator volutes  22  after the rotor  3  is rotatably mounted on the stator  2 . Like the base  21 , the cover  4  has a central opening  27 ′ in the shape of a double key hole with a central circular area  28 ′ and diametrically opposed windows  29 ′. 
     The indicator  1  can then be mounted on a rotary switch actuator with either the cover  4  or the stator base  21  facing upwardly. This enables the same visual indicator  1  to be used irrespective of whether the rotary valve actuator opens by turning in a clockwise or counter clockwise direction. That is, in order to change the direction of rotation of the rotor  3  relative to the stator  2  of the indicator  1 , the indicator  1  need merely be inverted before mounting on the valve actuator. 
     Referring now to FIGS. 21,  22 A and  22 B, a main housing  111  has a substantially rectangular cavity  113  for receiving circuitry for telemetry of indicator position to a remote site. Adjacent to a vertical wall  115  of the rectangular cavity  113 , which is made of nonmagnetic material, is a stepped cylindrical boss  117 . Rotatably mounted on the boss is a rotor driver  119  (see FIG. 23) having an interior cylinder  121  which is received within the bore of the boss and a coaxially spaced outer cylinder  123  which covers the boss. The inner cylinder  121  and outer cylinder  123  are connected to a common circular wall  125  atop the rotor driver  119 . The inner cylinder  121  has a hollow bore, square in cross-section, for receiving a key connected to the output shaft on the rotary valve actuator so that the rotor driver  119 , including inner cylinder  121  and outer cylinder  123  rotate in unison with the output shaft on the rotary valve actuator. 
     Surrounding the bottom of the rotor driver is a circular flange  127  having equally spaced teeth  129  on its upper surface. Fitted into a central axial opening  131  in the upper circular wall of the rotor driver  119 , and extending upwardly therefrom, is a hollow rod  133  (see FIG. 24) which is substantially rectangular in cross-section but having two of its opposite sides  135  somewhat outwardly rounded. Longitudinal cuts  137  are formed in opposite flat sides of the rod to form resilient fingers each of which has a radially outwardly protruding barb  139 . 
     Diametrically opposed semi-cylindrical bores  141  formed in the circumference of the upper portion of the rotor driver  119  extend downwardly from its top wall  125  and terminate in shoulders  143  in which there are threaded holes  145  for receiving screws  146 . 
     Four identical cam rings  149  (see FIG.  25 ), each of which has a central circular opening with a diameter slightly larger than the outer circumference of the rotor driver, and diametrically opposite bulges  151 ,  152  on their outer circumferences are provided for being fitted over the rotor driver  119  in vertically stacked disposition. Each of the cam rings  149  has a bottom surface  154  with four equi-angularly separated sets of teeth  153  and an upper surface having equally spaced teeth  155  all around in a configuration congruent with the teeth on the upper surface of the flange  127  of the rotor driver  119 . In the illustrated preferred embodiment of the invention, four cam rings  149  are stacked one atop another with the bottom teeth  153  of the lowermost cam ring engaging the teeth  129  on the rotor driver flange  127 , and the lower teeth  153  of each other cam ring meshing with the upper teeth  155  of the cam ring  149  beneath it. 
     The angular position of each cam ring  149  with respect to the rotor driver  119  can be adjusted by lifting the ring, rotating it relative to the rotor driver  119 , to its desired position, and then lowering the ring  149  until its bottom teeth  153  engage with the adjacent upper projecting teeth  129  (lowermost ring) or  155  (other rings). 
     In an embodiment of the invention where four cam rings are used, each cam ring  149  has a height of one fourth of the distance from the upper surface of the rotor driver flange  127  to the shoulders  143  in the semi-cylindrical bores on the circumference of the rotor driver  119 . A sleeve  161  (see FIG. 26) with a circular flange  163  is inserted into each of the two diametrically opposite screws in holes  145  so that the flanges  163  are urged against the upper surface of the uppermost cam ring  149  to secure all four of the cam rings  149  against rotational and axial movement relative to the rotor driver  119 . 
     Referring now to FIG. 27, an indicator assembly similar in construction to the one illustrated in FIGS. 1 and 2 and adapted to be mounted on main housing  111  has a stator  2 ′. The stator  2 ′ has a cover  4 ′ and a congruent base  21 ′, each with adjacent registration apertures  164 . A cylindrical pin  165  extends upwardly from an arcuate wall  166  of main housing  111 , partially circumscribing the boss  117 , for being received in one of the stator apertures  164  to prevent relative rotation between the stator  2 ′ and the main housing  111  once the indicator has been calibrated by rotating the stator  2 ′ to a desired position relative to its rotor  3 ′ and the output shaft on the rotary valve actuator, i.e., to establish a reference position for the control valve shaft. 
     The rotor  3 ′ has an axial substantially rectangular bore  167  which is congruent with the rod  133  that extends from the upper surface  125  of the rotor driver  119 . The rod  133  is received within the bore  167  of the rotor  3 ′ so that the rotor  3 ′ turns in unison with the rotor driver  119  and the cam rings  149 . The indicator assembly can be mounted in an upright or inverted position to allow for clockwise or counterclockwise operation of the valve actuator. When the rotor  3 ′ is placed onto the rod  133 , the resilient prongs formed by cuts  137  are compressed until the barbs  139  clear the uppermost surface of the rotor  3 ′. The barbs  139  can be squeezed together to enable removal of the rotor  3 ′ from the rod  133 . 
     Referring additionally to FIG. 28, a plunger housing  171  having a substantially flat base  173  and an upwardly extending column  175  is fitted within an opening  177  in the bottom of the main housing  111 . Molded into the column  175  are four vertically aligned cylindrical bosses  179  having horizontal cylindrical bores  181  in which there are disposed four corresponding cylindrical plungers  183 . Each of the plungers  183  has a solid cylindrical segment  184  proximate its respective boss  179  and an opposite end on which there is a integral square wall  185  in a plane transverse to the axis of the plunger, and from which there extend, substantially parallel to the axes of each plunger  183 , two parallel spaced walls  187 . Mounted between the spaced walls of each plunger  183  is a magnet assembly  188  formed from two identical axially adjacent magnets which are in like polar disposition. 
     A vertical slot  189  is formed in the arcuate wall  166  of the housing to enable the cylindrical segments of the plungers  183  to protrude through the arcuate wall  166  for being engaged by the eccentricities  151  which form the camming surfaces of the cam rings  149 . A narrow vertical slot  193  is provided in a side of the column  175  for receiving a substantially rectangular leaf spring  195  (see FIG. 29) having four parallel fingers  197 . 
     When one of the cam rings  149  is rotated to a predetermined position, it engages one end of a corresponding plunger  183  for urging the plunger  183  horizontally in a direction away from the arcuate wall  166 . Each plunger  183  has a circular groove or neck  199  for receiving an end of a leaf spring finger  197  which has a semi-circular notch. Each of four leaf spring fingers is in the form of a tine cut into a substantially rectangular sheet of spring steel. Each one of the leaf spring fingers  197  urges its respective plunger  183  toward the arcuate wall  166  and through the slot  189  for enabling a cam surface  198  on its end proximate the rotor driver  119  to be engaged by the eccentricity  151  on its respective cam ring  149 . 
     Referring additionally to FIGS. 30A and 30B, four magnetically sensitive magnetic switches  203  are vertically arranged on a circuit board  205  which is mounted adjacent nonmagnetic wall  115 , with the circuit board  205  in a vertical plane transverse to the axes of the plungers  183 . When each plunger  183  is in a terminal position proximate its corresponding magnetic switch  203  and distal from the arcuate wall  166 , the magnetic field of its permanent magnet assembly  188  actuates an adjacent one of the magnetic switches  203  thereby opening or closing a circuit, depending on whether the magnetic switch  203  is connected in a normally open or normally closed configuration, to indicate rotation of the output shaft on the rotary valve actuator to its current position. Upon further rotation of the output shaft on the rotary valve actuator and the cam rings  149  to a different position, the plunger  183  is withdrawn from its position proximate its respective magnetic switch, under force of a leaf spring finger  197 . That is, the corresponding eccentricity  151  is rotated with the output shaft on the rotary valve actuator to a position which enables the plunger  183  to return toward the arcuate wall  166 , and the corresponding magnetic switch  203 , now free of the actuating magnetic field, returns to its normal position. An electrical terminal block  211  having twelve contacts, three connected to the contacts of each magnetic switch  203 , is mounted adjacent and edge of the circuit board  205  on which the magnetic switches  203  are mounted. 
     As can be seen in FIG. 31, each magnetic switch  203  is, preferably, a single pole, double throw switch, having three terminals, i.e., one common, one normally open, and one normally closed. The circuitry in the housing may be wired to each magnetic switch  203  for normal open or normal closed operation as can be seen with reference to FIG. 31. A decoder  204  can be connected to the switch terminals for determining from the states of the switches  203  and, hence, the position of the output shaft on the rotary valve actuator. The decoder can be connected to a telecommunications network and/or a computer (not shown) for transmitting and analyzing rotary valve actuator shaft position data. 
     Depending on the contour and relative dispositions of the eccentricities  151 , the use of four plungers  183  and four corresponding magnetic switches  203  enables twenty-four (four factorial) different control valve positions to be indicated. For example, there may be a separate indication for each 15 degrees of rotation of the output shaft on the rotary valve actuator from the reference position. 
     It is to be appreciated that the foregoing is a description of a preferred embodiment of the invention to which variations and modifications may be made without departing from the spirit and scope of the invention.