Abstract:
A hand drive for shut-off members is described, for example for membrane valves, the hand drive comprises a hand wheel for actuating the valve which is provided with a closure limiter and a valve lift limiter, the hand wheel is provided with two inserts mounted thereon for axial adjustability; and wherein the inserts interact with a threaded spindle coupled with a valve element so as to adjust the valve lift limiter and the closure limiter.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application is a continuation of prior filed copending PCT International application No. PCT/EP01/01430, filed Feb. 9, 2001. 
     
    
     
         [0002]    This application claims the priority of German Patent Application Serial No. 100 06 326.8, filed Feb. 12, 2000, the subject matter of which is incorporated herein by reference.  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The invention relates to a hand drive for opening and closing a shut-off member, and in particular to a membrane valve with a hand wheel and a threaded spindle coupled to a valve element which can be moved by the hand wheel in an axial direction.  
           [0005]    Various valve designs are known in the art that limit movement of the valve stem. For example, CA 106 26 88 discloses a radiator valve with a housing carrying a valve stem with plate and loading spring on the valve stem above the valve plate. The valve seal can be removed without removing the valve tensioning spring. U.S. Pat. No. 5,647,397 discloses a valve which allows adjusting a minimum flow cross section via an adjustable limit stop. A coupling rod passes through the cover of the valve housing and serves as an indicator for the valve position. However, there is a need for a valve wherein the closure position of the valve element and preferably also the valve lift are limited, preferably with an element that is integrated with the valve.  
         SUMMARY OF THE INVENTION  
         [0006]    It is thus an object of the present invention to provide an improved hand drive for shut-off members, obviating the afore-stated drawbacks.  
           [0007]    According to one aspect of the invention, a hand drive for opening and closing a shut-off member, in particular a membrane valve, includes a valve element, a hand wheel and a threaded spindle coupled to the valve element, with the spindle axially moveable by the hand wheel, and a first limiter device for limiting the closure position of at least one of the threaded spindle and the valve element disposed on the hand wheel. For also limiting the valve lift of the valve element and/or the valve spindle, a second limiter device is arranged on the hand wheel.  
           [0008]    Advantageously, the hand wheel is provided with an inside thread in which an insert provided with a radial collar is threaded so as to be adjustable in an axial direction, whereby the threaded spindle is also provided with a radial collar. The collar of the insert can axially contact the collar on the threaded spindle for limiting the closure position of the valve element.  
           [0009]    Preferably, the insert is provided with an interior thread into which another axial displaceable insert with a radial collar is screwed. The collar of the other insert can axially contact the collar on the threaded spindle for limiting the valve lift of the valve element.  
           [0010]    According to another embodiment of the invention, the hand wheel is provided with a covering cap for the inserts, wherein this covering cap is connected via respective n-sided flat (for example, a 12-sided flat) with each of the hand wheel and the two inserts, so as to prevent an unintentional rotation of the two inserts relative to each other or relative to the hand wheel.  
           [0011]    Advantageously, the hand wheel is non-rotatably coupled with yet another insert, which is secured in a valve a housing and connected with the threaded spindle via a thread, wherein the hand wheel is fixed in the axial direction between the valve housing and the insert.  
           [0012]    Advantageously, a visual indicator is fixedly attached to the threaded spindle, whereby the collar of the threaded spindle can be formed on the visual indicator.  
           [0013]    Advantageously, the device that limits the closure position of the threaded spindle can be arranged inside the second device that limits the valve lift of the threaded spindle.  
           [0014]    Further features and advantages of the present invention will be apparent from the following description of preferred embodiments and from the claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
       [0015]    The following figures depict certain illustrative embodiments of the invention in which like reference numerals refer to like elements. These depicted embodiments are to be understood as illustrative of the invention and not as limiting in any way.  
         [0016]    [0016]FIG. 1 shows schematically a cross-sectional view of a preferred embodiment of the hand drive of the invention,  
         [0017]    [0017]FIG. 2 shows a cross-sectional view of an insert for limiting the closure position of the valve element,  
         [0018]    [0018]FIG. 3 shows a cross-sectional view of an insert for limiting the valve lift of the valve element,  
         [0019]    [0019]FIG. 4 shows a cross-sectional view of a covering cap for securing the insert of FIGS. 2 and 3 against unintentional rotation, and  
         [0020]    [0020]FIG. 5 shows a top view of the covering cap of FIG. 4. 
     
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0021]    The invention is directed to hand drive for opening and closing a shut-off member, in particular a membrane valve.  
         [0022]    Referring now to FIG. 1, a hand drive  10  for operating shut-off members, such as a valves, includes a hand wheel  12  which is secured and held in a fixed axial position on a valve housing  14  (only partially shown), as will be described below. A valve element  16  is arranged in the valve housing  14  for opening and closing a valve seat (not shown). The valve element  16  is suitably connected with a threaded spindle  18  which can be moved axially with a hand wheel  12  via an insert  22  in either of two directions.  
         [0023]    The hand wheel  12  is non-rotatably connected with the insert  22 , for example with an n-sided flat  50  which can be constructed, for example, in form of a 12-edged flat. The insert  22  has an interior thread which engages with an exterior thread of the threaded spindle  18 . The hand wheel  12  is axially held between a collar  62  of the insert  22  and a support ring  24  disposed in an annular groove of the insert  22 .  
         [0024]    This threaded insert  22  also has a flange  26  which makes contact with the inside of a flange  28  of the valve housing  14 , whereas the end  64  of the hand wheel  12  makes contact with the outside of the flange  28  of the valve housing  14 .  
         [0025]    In this way, the hand wheel  12  is axially fixed on the valve housing  14 , so that it can only perform a rotational movement, but not an axial movement.  
         [0026]    The valve element engages with a nose  30  in an axial groove (not indicated by a reference numeral) in the valve housing and is thereby secured against rotation.  
         [0027]    The hand wheel  12  is provided with an interior thread  66 , in which an insert  32  which has an exterior thread  68  is screwed, while still allowing axial adjustment.  
         [0028]    This insert  32  has a radial, inwardly pointing collar  34 , which is bounded by a central bore  52 , whose diameter is slightly larger than the outside diameter of the threaded spindle  18 .  
         [0029]    The insert  32  is also provided with an interior thread  70 , in which an axially displaceable insert  36  having an outside thread  72  is screwed. The insert  36  has a radially inwardly oriented collar  38  which is bounded by a central bore  54 .  
         [0030]    The insert  32  is axially adjustable in the interior thread  66  of the hand wheel  12 , whereas the insert  36  is axially adjustable in the interior thread  70  of the insert  32 .  
         [0031]    A visual indicator  20  is axially screwed on and affixed to the threaded spindle  18 . The visual indicator  20  extends through the hand wheel  12  to the outside and is provided to indicate the position of the valve element  16 .  
         [0032]    The end of the visual indicator  20  that abuts the threaded spindle  18  is provided with a radially outwardly oriented collar  40 . The collar  40  which also can be formed directly on the threaded spindle  18 , cooperates, as will be described below, with the collar  34  of the insert  32  to limit the closing movement, and with the collar  38  of the insert  36  to limit the valve lift.  
         [0033]    As indicated in FIG. 1, the hand wheel  12  is provided with a, covering cap  42  which is placed on the hand wheel  12  and covers the inserts  32  and  36  to the outside.  
         [0034]    The covering cap  42  is non-rotatably connected with the hand wheel  12  and with each of the two inserts  32  and  36  to at least partially prevent unintentional rotation of the two inserts  32 ,  36  relative to each other and relative to the hand wheel  12 .  
         [0035]    To connect the covering cap plate  42  with the hand wheel  12 , the covering cap plate  42  is provided with an in interior n-sided flat  44 , for example an interior 12-edged flat, which is placed in clamping engagement on a corresponding exterior n-sided flat  74  of the hand wheel  12 .  
         [0036]    The covering cap  42  also has an interior n-sided flat  46 , for example an interior 12-edged flat, which engages with a corresponding exterior n-sided flat  56  of the insert  32 .  
         [0037]    Lastly, the covering cap  42  is provided with an exterior n-sided flat  48  which engages with a corresponding interior n-sided flat  58  of the insert  36 .  
         [0038]    When the covering cap  42  is in place, the inserts  32  and  36  are secured against unintentional rotation relative to each other and relative to the hand wheel  12 .  
         [0039]    The covering cap  42  also has a central bore  60  through which the visual indicator  20  extends.  
         [0040]    The closure limit and the valve lift limit for the valve element  16  are adjusted as follows.  
         [0041]    When the covering cap  42  is removed, the required minimal opening for a desired minimal flow of the shut-off member is set by turning the hand wheel  12 . Thereafter, the axially adjustable insert  32  is adjusted upwardly (direction with reference to FIG. 1), until its collar  34  contacts the collar  40  of the visual indicator  20 . The outside diameter of the collar  40  is somewhat greater than the inside diameter of the collar  34 .  
         [0042]    The closure limit of the valve and/or the desired minimal flow is thereby set.  
         [0043]    For setting the maximum flow, the hand wheel  12  is turned until the desired maximum flow is reached. Thereafter, the insert  36  which is axially displaceable in the insert  32 , is pulled downwardly (direction with reference to FIG. 1), until its collar  38  contacts the collar  40  of the visual indicator  20 . The outside diameter of the collar  40  is somewhat greater than the inside diameter of the collar  38 .  
         [0044]    When the collar  40  contacts the collar  38  of the insert  36 , the maximal valve lift and thereby also the desired limit stop of the threaded spindle  18  and/or the valve element  16  are adjusted.  
         [0045]    After these adjustments have been made, the covering cap  42  is put back in place, whereby the positions of the inserts  32  and  36  relative to each other and to the hand wheel  12  are fixed, i.e., secured against unintentional rotation.  
         [0046]    While the invention has been disclosed in connection with the preferred embodiments shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art. Accordingly, the spirit and scope of the present invention is to be limited only by the following claims.  
         [0047]    What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims: