Abstract:
The tap intended for controlling the flow of a fluid, for example of a gas, comprises a tap body ( 34 ), an inner member ( 36 ) for opening and closing the passage of the gases, an outer rotary operating handwheel ( 42 ), a connection means ( 40 ) connecting the operating handwheel ( 42 ) to the closing member ( 36 ) and means limiting the movement of the operating handwheel ( 42 ) and of the opening and closing member ( 36 ) in the opening direction of the tap. In order to avoid the tap becoming jammed in the open position, said means limiting the movement of the operating member consist of an abutment ( 44 ) and a counterabutment ( 46 ) with frontal contact, which are arranged respectively on a rotary element and on the body ( 34 ) of the tap, or vice versa.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS  
       [0001]    This patent application is a continuation-in-part of copending U.S. patent application Ser. No. 09/770,903, filed Jan. 26, 2001, pending, which is based on Luxembourg Patent Application No. 90520, filed Feb. 10, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    The present invention relates to a tap for controlling the flow of a fluid, comprising a tap body, an inner member for opening and closing the passage of the fluid, an outer rotary operating member, a connection means connecting the operating member to the closing member and means limiting the movement of the operating member and of the opening and closing member in the opening direction of the tap.  
         BACKGROUND OF THE INVENTION  
         [0003]    Although not being limited to this, the invention relates, more particularly, to a tap for bottles or tanks containing compressed or liquefied gas. In this type of tap, the connection means may be a rod and the means for limiting the movement in the opening direction generally consist of one or two spindles passing through the body of the tap in the transverse direction perpendicularly to the movement of the rod and tangentially relative to the latter. For this purpose, the rod comprises, in its central region, an annular contraction allowing the passage of the two spindles and the rotation of the rod. These two spindles and the base of the contraction form abutments and counterabutments defining the end of travel of the rod and the stopping of the opening movement of the tap.  
           [0004]    The disadvantage of this known system is that, at the end of movement and since the tap is generally opened fully, the two spindles approach the bottom of the contraction of the rod tangentially on account of the rotation of the rod. Consequently, contact between the rod and the spindle or spindles is frictional or rubbing contact, that is to say progressive clamping and even jamming of the tap in the opening position occurs.  
           [0005]    This clamping or jamming of the tap requires a great amount of manual force when the tap is to be closed and prompts the use of a tool, such as pliers. This may, however, give rise to carelessness and has already caused accidents on opening the tap. To be precise, it has already happened that an operator, wanting to release the tap by means of a tool, has turned the operating member in the wrong direction, that is to say in the opening direction, until the head of the tap has fractured. This may obviously present a serious risk if the gases are toxic or explosive.  
         BRIEF SUMMARY OF THE INVENTION  
         [0006]    The object of the present invention is to provide a novel tap of the type described in the introduction, which does not have this disadvantage, that is to say a tap without the risk of clamping or jamming when the tap is opened fully.  
           [0007]    In order to achieve this object, the invention proposes a tap of the type described in the introduction, which is characterized in that said means limiting the movement of the operating member consist of an abutment and a counterabutment with frontal contact, which are arranged respectively on a rotary element and on the body of the tap, or vice versa.  
           [0008]    Since there is no frictional contact between the abutment and counterabutment, there is no risk that the tap will become clamped or jammed. The operator can easily close the tap without exerting excessive force and without risking making a mistake over the direction of rotation and tightening the tap even more.  
           [0009]    During opening and at the penultimate turn in the rotation of the operating member, the abutment and counterabutment do not yet come into contact, which means that, when they stop the rotation of the operating member, they are in mutual contact over a height which is smaller than the pitch of the threads between the rotary elements and the body of the tap. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Other particular features and characteristics of the invention may be gathered from the detailed description of an embodiment given below by way of illustration, with reference to the accompanying drawings in which:  
         [0011]    [0011]FIG. 1 is a vertical section through a known tap.  
         [0012]    [0012]FIG. 2 is a vertical section through a tap according to the present invention.  
         [0013]    [0013]FIG. 3 is a horizontal section through the tap of FIG. 2 along the sectional plane III-III.  
         [0014]    [0014]FIG. 4 shows a sectional view of a second embodiment of a valve during the opening phase corresponding to the penultimate turn of the operating handwheel.  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    The known tap in FIG. 1, of which only the elements necessary for understanding the problem have been illustrated, comprises a tap body  10 , preferably made of metal, for example bronze. The tap is actuated by means of an operating handwheel  12  which is fastened with the aid of a central screw  14  to a rod  16  screwed into the upper part of the body  10 . On the opposite side to the handwheel  12 , the rod  16  is connected directly or indirectly to the closing member, not shown, of the tap. Rotation of the member  12  consequently generates an axial movement of the rod  16  and of the closing member.  
         [0016]    As shown in FIG. 1, the rod  16  comprises, in its middle region, an annular contraction  18  of a diameter smaller than that of the head of the rod  16 . Moreover, one or preferably two spindles  20  are fastened transversely in the wall of the body  10  of the tap and pass through this contraction  18 . These spindles  20  prevent the rod  16  from being unscrewed completely and form a stop abutment during the opening of the tap as a result of contact between the bottom  22  of the contraction and the spindles  20 . For this purpose, the bottom  22  is rounded according to the curvature of the spindles  20 .  
         [0017]    However, as explained in the introduction, when the tap is opened, the bottom  22  of the contraction does not come into abutment on the spindles, but, because of the rotation of the rod, tangential frictional or shearing contact occurs between the rod  16  and the spindles  20 , and this may give rise to excessive clamping or jamming of the tap in the opening position.  
         [0018]    To overcome this disadvantage, the invention has proposed a novel tap, one embodiment of which is illustrated by way of example in FIGS. 2 and 3. This tap is intended for opening and closing communication between two pipes  30  and  32 . The tap comprises a body  34 , in which is located an opening and closing member  36  co-operating with a seat  38 . The closing member  36  forms the lower part of a connecting rod  40  which is arranged axially in the body  34  and which is integral with an operating handwheel  42  outside the tap. The upper part of the connecting rod  40  is provided with an external thread co-operating with a corresponding thread in the head of the body  34 , with the result that a rotation of the handwheel  42  causes the rod  40  to rise or fall, depending on the direction of rotation.  
         [0019]    According to the present invention, the connecting rod comprises an outer radial abutment  44 , whilst the body  34  comprises an inner radial counterabutment  46 . The abutment  44  and the counterabutment  46  are arranged in such a way that, during the rotation of the connecting rod  40 , the abutment  44  passes below the counterabutment  46  at the penultimate turn in the rotation of the handwheel  42  in the opening direction. By contrast, at the end of the last rotational turn and after the rise over a height corresponding to the pitch of the thread of the upper part of the connecting rod  40 , the abutment  44  butts on the counterabutment  46 , as illustrated in FIG. 2. The abutment  44  consequently strikes the counterabutment  46  perpendicularly without any friction and without the risk of clamping or jamming.  
         [0020]    The location of the abutment  44  and of the counterabutment  46  is only one example of implementation. The abutment  44  could, for example, be provided on the inner face of a peripheral skirt of the handwheel  42  and the counterabutment could be provided on the outer surface of the body  34 .  
         [0021]    The abutment  44  and the counterabutment  46 , instead of forming an integral part of the rod  40  and of the body  34  respectively, this part being obtained, for example, by machining, could be formed by pins made integral with these components.  
         [0022]    Moreover, the rod  40  could be smooth over its entire height, and its axial movement could be generated by means of a thread provided on the inner face of a cylindrical skirt integral with the handwheel  42  and co-operating with a corresponding thread outside the body  34 .  
         [0023]    Finally, the handwheel could be replaced by a polygonal head which would be actuated by means of a special spanner.  
         [0024]    For a valve as described hereinabove to operate reliably it is desirable for the abutment and the counterabutment to contact over a large part of the mutual surfaces that is to say over most of their axial length. If, for example, the abutment and the counterabutment are, the penultimate time the abutment passes the counterabutment, still separated by an axial distance which is barely smaller than the pitch of the screw which axially moves the moving abutment, then the two abutments will come into mutual contact only via their respective axial edges in order to stop the turning. Now, this may, in the long-term, lead to wear on their contacting edge and finally culminate in frictional contact, placing the valve back in the problematical situation described above.  
         [0025]    This risk is therefore dependent on parameters which are of deciding importance to the area of contact between the abutment and the counterabutment. These are, in this instance, the pitch of the screw which axially moves the moving abutment, the respective angular positions of the moving abutment and of the counterabutment, and the manner of assembly.  
         [0026]    For this risk not to exist, it is necessary for the arrangement to be such that the penultimate time the abutment passes the counterabutment, the axial distance between these two abutments is minimal, just enough to allow them to pass one another without contacting.  
         [0027]    [0027]FIG. 4 shows an embodiment of a valve which comprises means allowing the operating handwheel to be mounted in such a way that this condition is met. This embodiment employs the possibility of positioning the abutment and the counterabutment on the body of the valve and on the operating handwheel as mentioned hereinabove.  
         [0028]    The valve comprises a valve body  50 , preferably made of metal, for example made of bronze and through which there passes axially a cylindrical bore  52  in which there is a seat  54  at the intersection between an inlet connector and an outlet connector for fluid, for example gas.  
         [0029]    The valve is operated by an operating handwheel  56  which is fixed, for example using a screw or any other means, to a connecting rod  58  which is screwed into the upper part of the body  50  or of an intermediate bushing. At the opposite edge to the handwheel  56 , the rod  58  is connected directly or indirectly to an opening or shut-off member, not shown, which collaborates with the seat  54  to uncover or shut off the passage for the gas. The opening and shut-off member could also constitute the lower part of the rod although it is preferable to have a separate opening and shut-off member which does not turn with the connecting rod  58 .  
         [0030]    Turning the operating handwheel  56  therefore causes axial translation of the rod  58  and of the opening and shut-off member in the bore  52  of the body  50  of the valve.  
         [0031]    The body of the valve comprises on its upper edge, a counterabutment  60  which extends radially outwards and is intended to halt an abutment  62  which extends radially inwards from the base of the handwheel  56 .  
         [0032]    The medallion above the figure shows a cross section through the upper end  58   a  of the connecting rod  58  which is intended to take the operating handwheel. This part  58   a  is splined around its entire periphery with a series of vertical splines  64  which extend over the entire penetration height of the operating handwheel  56 . The bore in the handwheel which penetrates the head  58   a  of the rod has corresponding splines. These splines, as the handwheel  56  is fitted onto the head  58   a  of the rod  58  and prior to screw-fastening, allow the optimum angular position to be chosen for the handwheel which corresponds to maximum contact between the counterabutment  60  and the abutment  62  at the end of opening.  
         [0033]    In practice, mounting is performed as follows, in the knowledge that, as shown in the figure, the distance A is the distance between the upper edge of the abutment  62  and the base of the centre of the handwheel which rests on the head  58   a  of the rod and the distance B is the distance between the lower edge of the counter-abutment  60  and the upper edge of the head  58   a  of the rod  58 . If the distance A is fixed, the distance B varies according to the position of the rod  58  and of the handwheel. Before fitting the operating handwheel  56 , the rod  58  is turned in the opening direction which causes the rod  58  to emerge from the body  50  and increases the distance B. This turning is continued until the difference between the distance A and the distance B is minimal, for example a fraction of mm. The handwheel  56  is then fitted on to the head at the splines  64 , taking care that the handwheel lies in an angular position in which the abutment  62  is as close as possible to the counterabutment  60 . In fact the counterabutment  60  and the abutment  62  cannot lie in the same angular position otherwise they would impede the fitting of the handwheel  56 . It is then possible to fix the handwheel  56  by tightening its fixing screw. In other words, the handwheel  56  is mounted in a valve-open position which corresponds to the penultimate turn of the handwheel for opening. In effect, given the small distance between the upper edge of the abutment  62  and the lower edge of the counterabutment  60 , if the handwheel is turned through one additional turn, the abutment  62  can no longer pass the counterabutment  60  and there will be frontal contact between these abutments over a relatively large area.  
         [0034]    While the assembly has been described hereinabove in “slow motion” it is obvious that, in practice, assembly is performed automatically and in a programmed way under the control of sensors.  
         [0035]    While the embodiment of FIG. 4 has been described with reference to external abutments, the person skilled in the art will be able to conceive a similar solution using internal abutments, as in the embodiment of FIGS. 2 and 3.  
         [0036]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.  
         [0037]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.  
         [0038]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.