Abstract:
A valve assembly ( 20 ) including a valve body ( 24 ) and a position-indicating knob assembly ( 28 ) is provided wherein the assembly ( 28 ) indicates three different valve positions, namely valve closed, partially opened and full open positions. The preferred assembly ( 28 ) includes a rotatable knob ( 44 ) including a viewing port ( 80 ) therein, together with an indicator ring ( 40 ) having three differently colored regions ( 62 - 66 ) corresponding to the different valve positions. A coupling assembly ( 42, 80, 70, 90 ) operably couples the knob ( 44 ) and indicator ( 40 ) so that the individual colored regions ( 62 - 66 ) come into view through the port ( 80 ) when the valve body ( 24 ) reaches the different valve positions. The assembly ( 28 ) is particularly useful with valves requiring greater than one revolution between valve closed and valve full open positions, such as valves used in conjunction with emergency oxygen cylinders on aircraft.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention is broadly concerned with position indicating knob assemblies adapted for attachment to rotatable on-off valves in order to indicate via distinct and perceptible indicators the position of the valve in various positions such as valve closed, valve partially opened, and valve full open positions. In preferred forms, the invention is concerned with such knob assemblies, and the combination thereof with valve bodies, wherein the knob assembly includes a differently colored valve position indicator which displays respective colors corresponding to different valve positions.  
         [0003]     2. Description of the Prior Art  
         [0004]     Emergency oxygen supplies in aircraft are in the form of oxygen cylinders equipped with selectively operable valves. These valves are designed to open gradually in order to protect downstream components from pressure surges. Consequently, the valves typically require multiple rotations of a valve stem to move between closed and open positions. When such cylinders are installed in an aircraft, the valve is supposed to be in the full open position thereof, and it is lock-wired in this position. However, if the valve is only partially opened (e.g., only one revolution in a six revolution to open valve), the pilots panel reading will show the valve opened because positive oxygen pressure would exist, and the valve would be lock wired in this position. However, in the event of an emergency decompression, the partially opened valve would deliver insufficient emergency oxygen, and catastrophic results could ensue.  
         [0005]     Conventional knob position indicators use simple on-off position pointers. This method is acceptable for valves that go from full closed to full open in less than one stem revolution. However, valves with greater than one revolution from full closed to full open cannot make use of a simple pointer. In some applications, an electromechanical approach has been utilized to sense the position of the valve via electrical switch components. A disadvantage of this approach is the vulnerability to displacement or misalignment of the switch components, such that the switch contacts close prematurely or not at all. Further, this approach cannot distinguish between three valve conditions (fully closed, partially open and full open) unless multiple switches are used. Finally, the switch concept is dependent on a source of electrical power and also requires circuitry to convert the switch signals to a form perceptible to users.  
         [0006]     U.S. Pat. No. 3,910,308 describes a valve signal handle which is capable of indicating full closed and full open position using different colors. However, this device is incapable of indicating an intermediate valve position between full open and full closed. U.S. Pat. Nos. 3,151,598, 3,183,885, 3,241,515, 3,547,071 and 5,769,118 all describe various valve and turn-indicating units making use of digitized counters. For example, U.S. Pat. No. 3,547,071 describes a turn indicator for showing the number of turns made by a shaft equipped with a knob or the like. A series of indicator numerals are provided so that each time the knob is turned one full revolution a new number is shown. These patents also describe combination devices which not only count revolutions, but also provide angular displacement indicators.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention overcomes the problems outlined above and provides positioning indicating knob assemblies adapted for attachment to rotatable valve stems in order to provide plural position indicators which are perceptible and distinct. Broadly speaking, the knob assemblies of the invention include a rotatable knob, an indicator having first, second and third perceptible and distinct valve position indicators corresponding to the first, second and third different valve stem positions. A coupling assembly is provided between the knob and indicator so that the first position indicator becomes perceptible only when the valve stem is in the first position thereof, the second position indicator becomes perceptible only when the valve is in the second stem position, and the third position indicator becomes perceptible only when the valve is in the third stem position thereof.  
         [0008]     In preferred forms, the knob includes a viewing port and the position indicators are individually colored regions of an indicator ring rotatable with the knob. As the knob is rotated, the coupling assembly serves to shift the indicator ring relative to the knob so that when the valve reaches the appropriate position, the proper colored region comes into registry with the viewing port.  
         [0009]     The knob assemblies of the invention find particular utility in conjunction with aircraft oxygen cylinders, and permit visual inspection of the cylinder valves in order to confirm the position of the valves. Thus, during and after installation of the cylinders it is a simple matter to visually confirm that the valves are indeed in the requisite full open position, by simply looking at the valve color indicator port 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1  is a perspective view of a valve assembly in accordance with the invention equipped with a specialized position-indicating knob assembly;  
         [0011]      FIG. 2  is a perspective view similar to that of  FIG. 1 , but illustrating the knob assembly in exploded relation;  
         [0012]      FIG. 3  is a perspective view similar to  FIG. 2 , but showing the valve assembly and exploded knob assembly in a different perspective;  
         [0013]      FIG. 4  is a fragmentary view in partial vertical section illustrating the valve assembly of the invention mounted on a conventional pressurized bottle containing oxygen or other gas;  
         [0014]      FIG. 5  is a horizontal sectional view of the preferred knob assembly and depicting the latter in the closed position of the valve assembly;  
         [0015]      FIG. 6  is a view similar to that of  FIG. 5 , but illustrating the knob assembly during opening of the valve assembly;  
         [0016]      FIG. 7  is a view similar to that of  FIG. 6 , but showing the knob assembly in a further rotated condition;  
         [0017]      FIG. 8  is a view similar to that of  FIG. 6 , but depicting the knob assembly during deformation of the resilient ring forming a part of the knob assembly;  
         [0018]      FIG. 9  is a view similar to that of  FIG. 6 , but showing the condition of the knob assembly after the knob is opened one-half revolution;  
         [0019]      FIG. 10  is a view similar to that of  FIG. 6  but depicting the knob assembly in its full open position after six knob revolutions;  
         [0020]      FIG. 11  is a vertical sectional view taken along line  11 - 11  of  FIG. 6 ;  
         [0021]      FIG. 12  is a vertical sectional view taken along line  12 - 12  of  FIG. 5 ; and  
         [0022]      FIG. 13  is a vertical sectional view taken along line  13 - 13  of  FIG. 7 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0023]     Turning now the drawings,  FIG. 1  illustrates a valve assembly  20  in accordance with the invention, whereas  FIG. 4  depicts the assembly  20  operatively threaded into the neck of a high pressure oxygen bottle  22 . The assembly  20  broadly includes a main valve body  24 , depending draw tube  26  and knob assembly  28 . The valve body  24  and draw tube  26  are entirely conventional, and are used for valving the bottle  22  or any other source of pressurized gas or liquid. Accordingly, the constructional details and operation of these components need not be described in detail. It will be noted, however, that the valve body  24  has, adjacent its upper end, a circular block  30  surmounted by a pair of nuts  32  and  34 . A rotatable, flattened valve stem  36  extends upwardly from block  30  and through the nuts  32 ,  34 . As will be readily understood, rotation of the valve stem  36  effects opening and closing of the valve assembly  20 .  
         [0024]     Referring now to  FIGS. 2 and 3 , it will be seen that the knob assembly  28  is mounted atop block  30  and the nuts  32 ,  34 , and is operably coupled with valve stem  36 . The overall assembly  28  includes, from bottom to top, a detent block  38 , indicator ring  40 , elastomeric spring ring  42  and rotatable knob  44 . A screw  46  passes downwardly through the knob  44  and is threadably received within the bore of stem  36  in order to affix the entire assembly  28  to the valve body  24 .  
         [0025]     In detail, the detent block  38  includes a main, upright circular sidewall  48  presenting a hexagonal bottommost opening  50  designed to accommodate upper nut  34 . A lower spring-supporting segment  52  is located above the opening  50  and presents four equidistantly spaced, elongated recesses  54  with intermediate projections  55 . An elongated, slightly downwardly inclined spring finger  56  extends from each projection  55  along the length of the adjacent recess  52 . Additionally, the block  38  presents an upper, generally annular indicator-supporting segment  58  which includes a pair of opposite, inwardly extending detents  60 .  
         [0026]     The indicator ring  40  is of split-ring construction and has a total of thirteen strategically positioned recesses  62  formed along the inner surface thereof. The ring has three distinct colored regions on the upper face thereof, namely a red region  64 , a yellow region  66  and a green region  68 . An upstanding boss  70  is located between the regions  64  and  68 .  
         [0027]     The spring ring  42  includes a substantially circular segment  72  and a pair of opposed, outwardly extending, integral ears  74 . It will be noted that the thickness of the segment  72  is reduced somewhat at the regions of the ears  74  which is important for purposes to be described. The ring  42  may be formed of any suitable resilient, elastomeric material.  
         [0028]     The knob  44  includes a substantially planar upper wall  76  and a depending, ribbed skirt  78 . The upper wall is equipped with a circular viewing port  80  as well as a central, screw-receiving opening  84 . The underside of upper wall  76  includes a central, depending, stem-receiving boss  86  designed to receive and accommodate valve stem  36 , along with four depending lugs  88 , positioned as two opposing lug pairs which are slightly spaced apart as best illustrated in  FIGS. 5-10 . Finally, a circular slot  90  is provided along the underside of wall  76  and which extends a substantial distance around the periphery of the wall.  
         [0029]     The assembled relationship of the components of knob assembly  28  is best depicted in  FIGS. 11-13 . In particular, the detent block  38  is positioned over the upper nut  34 , with the latter received within the opening  50 . The lower ends of the inclined spring fingers  56  engage the upper surface of nut  34  as best seen in  FIG. 13 , in order to accommodate any dimensional irregularities in the components of the assembly to insure smooth operation thereof. The spring ring  42  is seated on the upper surface of lower segment  52  with the ears  74  thereof projecting between the opposed pairs of knob lugs  88 . The ring  40  is positioned on the upper surface of segment  58  with the ears  74  located within opposed ring recesses  62 . The knob  44  receives upstanding valve stem  36  within boss  86  and the screw  46  is treaded into the stem bore, such that skirt  78  surrounds all of the internal components of the knob assembly. During operation of the knob assembly described in detail below, the detent block  38  remains stationary, while the knob  44 , indicator ring  40  and spring ring  42  rotate relative to the detent block. The spring ring  42 , lugs  88 , boss  70  and slot  90  cooperatively form a coupling assembly serving to operatively couple the knob  44  and indicator ring  40  so that the respective colored regions  64 - 68  of the ring  40  are positioned beneath viewing port  80  when the valve is in its fully closed, partially open and full open positions, respectively.  
         [heading-0030]     Operation  
         [0031]     Attention is first directed to  FIGS. 5 and 12  which illustrate the position of the knob assembly  28  when the valve  24  is in the fully closed position. In particular, in this orientation one of the ears  74  of spring ring  42  is located within the recess  62  situated adjacent the counterclockwise end of red colored region  64 , with the opposed ear  74  being located in the opposite recess  62 ; also, boss  70  is seated within slot  90  and remains so throughout knob movement. As such, the user would perceive a red color through the viewing port  80 , indicating that the valve is fully closed.  FIG. 6  illustrates the condition of the assembly  28  when the assembly is opened one-quarter turn. In particular, it will be seen that turning of the knob  44  simultaneously turns the ring  42  because of the driving connection of lugs  88  on opposite sides of the ears  74 . Correspondingly, the ring  40  is also rotated owing to the location of the ears  74  within the previously described recesses  62 . During this one-quarter turn travel, there is no relative movement between the knob  44  and ring  40 , so that a red color is still observed through the port  80 .  
         [0032]      FIG. 7  illustrates the condition of the knob assembly  28  at a position just slightly less than one-half revolution and prior to the ears  74  encountering the detents  60 . Here again, the ring  42  has been rotated along with the knob  44 , and the ring  40  is similarly been rotated.  FIG. 8  illustrates the operation of the assembly  28  when the ears  74  encounter the detents  60 . As this occurs, the resilient ring  42  is deformed such that the ears  74  are retracted from the original recesses  62  and, during continued rotation, the ring  42  is rotated slightly relative to the indicator  40  until, as seen in  FIG. 9 , the ears  74  seat within the next adjacent pair of ring recesses  62 . In this orientation, it will be noted that the port  80  is now above the yellow colored region  66 , indicating that the valve is partially opened.  
         [0033]     As the knob  44  is further rotated another one-half revolution, the ears  74  of ring  42  again encounter the detents  60 , which thereby shifts the ears into the next set of opposed recesses  62 . This sequence continues for an additional five revolutions of the knob assembly; and owing to the length of the yellow colored section  66 , throughout this valve opening operation a yellow color is observed through viewing port  80 . At the end of the sixth revolution of the knob assembly, the ears  74  again encounter the detents  60 , causing the ears  74  to seat within the recess  60  adjacent the counterclockwise end of green colored region  68 , and the opposed recess. In this valve full open position, a green color is then seen through the port  80 .  
         [0034]     Thus, during rotation of the knob assembly  28 , the coupling assembly between the knob  44  and indicator ring  40  serves to sequentially change the relative position between the knob and indicator ring in a stepwise fashion. Of course, this operation is reversed during the closing of the valve, i.e, the indicator color seen through port  80  is initially green (indicating valve fully open), and then changes to yellow (indicating valve partially open) for five and one-half revolutions, and then changes to red (indicating valve closed) through the last one-half revolution.  
         [0035]     While in the illustrated embodiment the valve assembly  20  requires six full rotations of the knob assembly between full closed and full opened positions, it will be appreciated that a valve requiring a different number of revolutions could be used. In this case, the number and location of the recesses  62  should be adjusted so as to maintain the desired color indications in correlation with different valve positions.