Patent Publication Number: US-2005139268-A1

Title: Tap with position indicator

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application claims priority to European Patent Application No. 03079185.9 filed Dec. 24, 2003, and which is incorporated herein by reference.  
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
      Not Applicable.  
     BACKGROUND OF THE INVENTION  
      The present invention relates to a tap, especially a tap for a gas or liquefied gas cylinder, comprising a fixed tap structure including a tap body, an actuating wheel rotatable about an axis of rotation with respect to the fixed tap structure to open or close the tap, and a means for indicating the open or closed position of the tap, said means comprising a movable element for covering or exposing a signaling means, said signaling means indicating by its visibility or invisibility the open or closed condition of the tap.  
      Taps provided with a means or a device permitting an operator to see the closed or open condition of the tap on the exterior thereof are known in the state of the art. For example, in a known prior art tap a fixed ring or band is provided on the exterior surface of the tap body. This ring is normally masked by the actuating wheel of the tap and it has color different from the tap body and the actuating wheel. This simple system functions only with a tap having an upwardly and downwardly movable actuating wheel and stem assembly in view of the fact that the ring can only be uncovered or exposed by actuating wheel movement in axial direction relative to the tap body. Further, for a tap of very small opening movement, the actuating wheel moves only a very limited axial distance relative to the tap body and the ring indicating the open position of the tap would be only very slightly uncovered and therefore not be clearly discernible below the actuating wheel.  
      Known in the art are also taps having actuating wheels provided with windows through which marks can be seen on fixed tap structure indicating the open or closed position of the tap. However, these devices are limited to taps whose actuating wheel is only movable a fraction of a turn, such as a quarter turn, for opening and closing the tap.  
      Finally, in the prior art taps are known having relatively complex and cumbersome systems for indicating the open or closed condition of the tap.  
     BRIEF SUMMARY OF THE INVENTION  
      The object of the present invention is to avoid these disadvantages and to provide a tap having a simple means or device for indicating the open or closed condition of the tap, which is easily visible on the exterior of the tap, and which can be used on a tap having an upwardly and downwardly movable stem, on a tap having a rotating stem (not movable upwardly and downwardly) and also on a tap having an actuating wheel rotatable only a fraction of a turn or multiple turns for opening or closing the tap.  
      According to the invention the movable element of the indicating means is a skirt coupled, on one side, to the actuating wheel so as to be entrained in rotation therewith and coupled, on another side, to the fixed tap structure by a means causing, under the effect of rotational movement of the skirt in one or the other direction, an axial displacement thereof along the axis of rotation with respect to the actuating wheel and with respect to the fixed tap structure so as to cover or expose the signaling means.  
      Accordingly, the movable skirt of the means for indicating the open or closed position of the tap effects an upward or downward movement relative to the fixed tap structure in response to the rotational movement of the actuating wheel of the tap to uncover or cover the signaling means even if the actuating wheel or the tap stem does not move upwardly or downwardly. The coupling between the movable skirt and the fixed tap structure can be designed by selection of an appropriate angle of inclination or pitch angle of the engagement means between these two parts so as to produce a sufficient axial movement of the skirt to uncover or expose a large signaling surface of substantial height or width so as to be easily visible or discernible on the exterior of the tap. Similarly, for taps having a stem without axial movement or small axial movement and also for taps having a quarter turn actuating wheel for opening or closing the tap, a large signaling surface having a substantial height can be exposed.  
      According to a preferred embodiment of the invention the device or means for indicating the open or closed condition of the tap comprises an annular support member separate from the tap body (but being a part of the fixed tap structure) and mounted normally stationary with respect thereto, and the movable skirt surrounds the annular support member and is provided with an internal single or multiple threaded screw thread engaged with a correspondingly internally threaded portion of the support member. In this embodiment the signaling means is provided on the annular support member on a lower portion thereof to be exposed by the axial movement of the skirt when the actuating wheel of the tap is rotated in a direction to open the tap. At least the lower portion of the annular support member provided with the signaling means (or forming the signaling means) or the entirety of this member may be distinguished from the adjacent surfaces of the tap body and the actuating wheel by at least one of the conditions comprising a different surface finish, a different color, and a different material.  
      The annular support member is fixed to the tap body by a friction fit, namely a press fit, and it is moreover provided with a central polygonal or star-shaped opening having for example 24 angles or facets arranged in zigzag or in accordion-type fashion, engaged on an end portion of polygonal shape, for example square- or hexagonal shape, of a gland ring of the tap. The annular support member may have one or more rupture initiation areas to permit opening or closing of the tap in case of jamming of the skirt between the actuating wheel and the annular support member, by application of a sufficient force to the actuating wheel causing breakage of the support member at the rupture initiation areas. In addition, the retention force of the press fit engagement of the annular support member on the tap body and the design of the polygonal shape of the opening in the support member can be selected to permit the support member to be rotated about the tap body and the gland ring by application of a sufficient force to the actuating wheel to overcome the retention force of the press fit and deform the polygonal opening in case the support member is fabricated from a high strength material tending to resist breakage at the rupture initiation areas.  
      To couple the movable skirt to the actuating wheel for rotating therewith it is provided at its upper extremity with a flange provided with a plurality of projection portions or lobes spaced from one another in circumferential direction and received in recesses of corresponding shape formed in the interior of a cavity of the actuating wheel. The lower extremity of the skirt is visible below the actuating wheel at least in the position thereof covering the indicating means.  
      Preferably, in the tap closed position the movable skirt is in a lower position covering the lower extremity of the annular support member or the signaling means provided at its lower extremity or adjacent thereto and by rotational movement of the actuating wheel in a direction to open the tap the movable skirt is caused to be displaced axially upwardly to thereby uncover the lower end portion or extremity of the annular support member or its signaling means for indicating the condition of the tap so as to be easily visible, even from a remote location, on the exterior of the tap to thereby indicate the open position of the tap. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       FIG. 1  is a vertical sectional view of a rotating stem tap (stem without upward and downward movement) having a device according to the invention for indicating the open or closed condition of the tap;  
       FIGS. 2A and 2B  show a tap having an upwardly and downwardly movable stem and actuating wheel provided with a device according to the invention for indicating the open position ( FIG. 2A ) or the closed position ( FIG. 2B ) of the tap;  
       FIGS. 3A, 3B  and  3 C show the movable skirt and the annular support member constituting the device for indicating the open and closed condition of the tap,  FIG. 3A  showing the position of the elements of the indicating device in the closed condition of the tap,  FIG. 3B  showing the position of the elements of the indicating device in the open condition of the tap, and  FIG. 3C  showing the position of the elements of the indicating device in perspective view in open condition of the tap;  
       FIGS. 4A and 4B  show the movable skirt of the indicating device in vertical section ( FIG. 4A  taken along line A-A of  FIG. 4B ) and in bottom view ( FIG. 4B ), respectively; and  
       FIGS. 5A and 5B  show the annular support member of the device for indicating the open or closed position of the tap,  FIG. 5B  being a view in vertical section taken along line A-A of  FIG. 5A  and  FIG. 5A  being a bottom view of  FIG. 5B . 
    
    
      Corresponding reference numerals will be used throughout the several figures of the drawings.  
     DETAILED DESCRIPTION OF THE INVENTION  
      The tap according to the invention will now be described in greater detail. As shown in  FIG. 1 , the tap  10  includes a fixed tap structure having a tap body  12 . An actuating wheel or hand wheel  14  is coupled to a stem  16  which is in turn coupled to a movable seat element  18  carrying a sealing member  20  engaging a fixed seat  22  of the tap body  12  in the closed position of the tap  10 . The stem  16  is mounted for rotation in a gland ring  24  threaded into a threaded portion of the tap body  12  at the upper end thereof. The stem  16  is provided at its lower end with a square-shaped portion  26  engaged in a square-shaped cavity  28  of the movable seat element  18 . The movable seat element  18  is threaded into a threaded portion within the interior of the tap body  12 . The tap  10  is accordingly of the rotating stem type, namely the stem  16  and the actuating wheel  14  do not move vertically or axially for opening or closing the tap. Only the movable seat element  18  effects a vertical or axial movement when the stem  16  is rotated in the opening or closing direction of the tap  10 .  
      Referring further to  FIG. 1 , the mechanism for indicating the open or closed position of the tap, designated in its entirety by  30 , comprises an external cylindrical movable skirt  32  and an internal cylindrical annular support member  34  fixed to the tap body  12 . The movable skirt  32  is coupled to the actuating wheel  14  so as to be driven in rotation by the rotating wheel  14  while permitting an axial movement of the skirt  32  along the longitudinal axis A of the tap  10  relative to the annular support member  34  and also relative to the fixed tap structure including body  12  and support member  34 . The skirt  32  surrounds the annular support member  34  and the upper portion of the skirt  32  is received within the interior of the actuating wheel  14  while its lower portion is exposed and located exteriorly of the actuating wheel  14  below the same. The support member  34  is fixedly mounted by a pressed friction fit on the tap body  12  so as to normally prevent displacement or rotation of the support member  34  with respect to the tap body  12 . The annular support member  34  is also extended axially downwardly beyond the lower end of the actuating wheel  14 . The skirt  32  is provided with an internal screw thread  36 , see  FIG. 4A , and this thread is in engagement with an externally threaded portion  38  of the internal support member  34 , note  FIG. 5B .  
      As best shown in  FIG. 4B  the movable skirt  32  is provided at its upper end with a flange  40  having a plurality of projections, or lobes  42  of generally semi-circular shape extending outwardly and spaced from one another in circumferential direction of the skirt  32 . The projections  42  are received in recesses, for example 44, of corresponding shape, see  FIG. 1 , formed in the internal circumferential surface of a downwardly open cavity defined within the actuating wheel  14 . The skirt  32  is accordingly coupled to the actuating wheel  14  for rotation therewith and cannot move in rotational direction with respect to the actuating wheel  14 . During rotational movement of the actuating wheel  14  and the skirt  32  about the annular support member  34  and the tap body  12 , the projections  42  of the skirt  32  move vertically within the recesses  44  of the actuating wheel  14 . Any other means can be provided for coupling the movable skirt  32  to the actuating wheel  14  for rotation therewith, for example axial pins (not shown) fixed to the actuating wheel  14  and received in axial holes (not shown) formed in the movable skirt  32 .  
      The  FIGS. 5A and 5B  show the internal annular support member  34  which is normally stationary or fixed with respect to the tap body  12 . The annular support member  34  is provided at its upper end with a radial annular wall  44  provided in the center thereof with a polygonal opening  46 , preferably a star-shaped opening having 24 facets disposed in zigzag or of accordion-type fashion, or having 24 angles opening alternately inwardly and outwardly. In addition the radial annular wall  44  is provided with a plurality of elongated curved apertures  48  spaced from one another in circumferential direction and leaving predetermined rupture areas  50  between adjacent apertures  48 . The annular support member  34  is provided at the lower end of its internal cylindrical surface with a plurality of vertical ribs  52  frictionally engaging the external surface of the tap body  12  when the annular support member  34  is press fitted onto the tap body  12 . When the annular support member  34  is mounted on the tap body  12 , the polygonal opening  46  engages the polygonal, square-shaped or hexagonal end portion of the gland ring  24 , as shown in  FIG. 1 , to prevent rotation of the support member  34  about the tap body  12  and the gland ring  24 .  
      The  FIGS. 3A, 3B  and  3 C show the assembled annular elements or internal and external rings  32 ,  34  (namely the skirt  32  and the support member  34 ) of the indicating device. In the position of  FIG. 3A  the skirt  32  masks or covers the lower extremity of the support member  34 . In this position of the two elements  32  and  34  the tap is in the closed position. In the  FIGS. 3B and 3C  the movable skirt  32  is displaced upwardly and the lower portion  34   a  of the internal support member  34  is visible below the lower extremity of the external skirt  32 . This position is also shown in  FIG. 1  and represents the open condition of the tap  10 . The lower portion  34   a  of the support member  34  serves accordingly as signaling surface or portion for indicating the position of the tap and indicates the open position thereof when it is visible below the movable skirt  32 . Preferably, the two members  32  and  34  are fabricated from plastic material and at least the lower portion of the support member  34  has a different color than the movable skirt  32  and the tap body  12 , for example a red color. The signaling surface of the support member  34  may be formed by a colored band applied to member  34  or an annular painted area thereof. It is also possible to fabricate the element  34  from a different material than element  32  and tap body  12  and/or to provide for example a bright appearance or other surface finish for the lower extremity  34   a  of the support member  34 , particularly if the two elements  32  and  34  are metallic. The signaling surface may alternatively also be provided on the tap body  12  and may be a colored surface portion thereof or a colored band fixed thereto.  
      It will be understood that during rotation of the actuating wheel  14  the movable skirt  32  will rotate with the wheel  14  and due to the threaded engagement between the elements  32  and  34 , the external element or skirt  32  will move vertically while the internal element  34  remains stationary. The pitch angle of the threaded engagement between the two elements  32  and  34  is selected to be sufficiently high so as to uncover a substantial portion of the support member  34  at the lower extremity  34   a  thereof. An axial motion or substantial axial motion of the actuating wheel  14  is not necessary for exposing the lower portion  34   a  of the support member  34 . If the axial displacement of the actuating wheel is small or if its rotation is only a fraction of a turn, such as a quarter turn, the pitch angle of the threaded portions  36  and  38  is selected sufficiently high to ensure uncovering of a substantial portion of the lower extremity  34   a  of the support member  34 . It is also possible to provide multiple threaded screw threads to increase the axial displacement of the skirt  32 .  
      As mentioned hereinbefore, the indicating device according to the invention can also be used in combination with a tap having an upwardly and downwardly movable stem, namely a tap provided with an actuating wheel that moves axially with respect to the body when the wheel is rotated for opening or closing the tap. Such a tap is shown schematically in  FIGS. 2A and 2B , the  FIG. 2A  showing the open position and the  FIG. 2B  the closed position of the tap. The indicating device  30  comprising the skirt  32  and the annular support member  34  is the same as in the embodiment of  FIGS. 1, 3A ,  3 B,  3 C,  4 B,  4 B and  5 A,  5 B and does not need to be described here again in detail.  
      During the lifetime of the tap the skirt  32  may possibly get stuck between the internal support member  34  and the actuating wheel  14 . In this case the tap may be opened or closed by exertion of a larger actuation force on the actuating wheel  14  causing breakage of the predetermined rupture areas  50  of the annular support member  34 . If the support member  34  is fabricated from a strong material tending to resist breakage of the predetermined rupture areas  50  the larger force applied to the actuating wheel  14  may cause rotation of the support member  34  about the tap body  12  and about the polygonal end portion of the gland ring  34  by deformation of the polygonal opening  46  of the annular support member  34 . Of course, this force must also overcome the retention force of the press-fitted engagement of the annular support member  34  on the tap body  12 . The frictional engagement is accordingly a relatively weak frictional engagement but which is sufficient to normally retain the annular support member  34  against rotation in combination with the engagement of the polygonal opening  46  on the polygonal end portion of the gland ring  24 .  
      It is to be understood that instead of the threaded portions  36  and  38  of the external and internal elements  32  and  34  it is also possible to provide any other means causing a vertical or axial movement of the external element  32  with respect to the internal element  34  when the external element  32  is rotated about the axis A of the tap  10 .  
      For example, instead of the threaded portions  36  and  38  the external portion  32  may also be provided with pins (not shown) spaced circumferentially from one another and extending inwardly from the internal cylindrical surface of the skirt  32  to be received in helical grooves (not shown) of the internal element  34 . Alternatively, the pins may be provided on the internal support element  34  and received in helical grooves of the skirt  32 .  
      In another embodiment, the internal element or the support member  34  may be eliminated and the movable skirt  32  may be mounted directly on the tap body  12  and coupled thereto by any appropriate means, such as a threaded engagement, for causing vertical or axial displacement of the skirt  32  when it is rotated by means of the actuating wheel  14  about the axis A of the tap  10 . In this case a portion of the body  12  of the tap  10  to be uncovered or masked by the skirt  32  serves as the signaling means or the signaling surface to indicate the position of the tap  10 . This portion of the tap body  12  may be colored, for example in red, or may have another surface finish, for example a bright appearance to distinguish it from the adjacent surfaces of the tap  10  and the skirt  32 , or may be provided with a colored band or other means, applied to the external surface of the tap body  12 .  
      Further, by an appropriate design of the means causing the external element  32  to move vertically when rotated by means of the actuating wheel  14 , for example by an appropriate form of the threaded portions  36  and  38 , such as a right hand thread or a left hand thread, the device for indicating the position of the tap  10  may be formed to mask the indicating portion of the tap body  12  or of the member  34  in the closed position of the tap and to expose the indicating portion in the open position of the tap, as described hereinbefore, or contrarily, namely to mask the indicating portion in the open position and to expose it in the closed position of the tap.  
      From the preceding description it will be understood that the mechanism of the invention permits one to see the open or closed position of the tap  10  on the exterior thereof even when the stem  16  and the actuating wheel  14  do not move vertically or axially along the axis A for opening or closing the tap  10 . The same functioning is also insured for a tap whose actuating stem  16 ′ is threaded into the gland ring  24 ′ or into the tap body and carries the sealing member  20  adapted to tightly engage the tap seat  22  ( FIGS. 2A and 2B ). If in a tap of this type the pitch of the screw thread between the stem  16 ′ and gland ring  24 ′ or the tap body is small for a small opening movement, a signaling surface  34   a  or an indicating portion of substantial height may nevertheless be exposed by providing a larger pitch angle for the engaged threaded portions of the external element  32  and the internal element  34  than for the threaded engagement of the stem  16 ′ in the gland ring  24 ′ or in the tap body  12 .  
      Finally, the signaling portion or surface  34   a  of the internal element  34  does not need to extend down to the lower extremity of the element  34 , but the internal element  34  may be provided at its lower extremity with a small circumferential external stop (not shown) on which the external portion  32  comes to seat in closed or open position of the tap, so as to mask the signaling portion or surface  34   a  provided above the circumferential stop. Also, the external element  32  may have one or a plurality of windows (not shown) spaced circumferentially and/or axially from one another and adapted to be aligned with one or more signaling surfaces (not shown) arranged in a similar manner on the internal element  34  or on the tap body  12 .  
      A spring (not shown) may be provided between the actuating wheel  14  and the support member  34  to eliminate any backlash between these elements and to serve to safely retain the parts in position.  
      According to a still further embodiment, the skirt can be totally retractable into the interior of the actuating wheel in one of the two positions (open or closed) of the tap and extended partly from the interior of the wheel in the other position of the tap. In this case the signaling means may be provided on the tap body or may be provided on the portion of the skirt to be extended from within the actuating wheel in one of the two positions of the tap.  
      Other variations or modifications may be made by the skilled person to the preferred embodiments described hereinbefore and shown in the drawings without leaving the scope of the invention as defined by the annexed claims.