Abstract:
A valve means ( 1 ) containing a switching element in the form of a switching rocker member ( 13 ). The rocking arms ( 18  and  18 ′) placed on either side of the pivotal portion ( 15 ) of the switching rocker member ( 13 ) are respectively engaged by a respective actuating diaphragm ( 35  and  35 ′) and adjacent thereto there is a closure portion ( 27  and  27 ′) associated with a duct opening ( 24  and  25 ). A valve means designed in this manner renders possible a particularly flat, planar structure with compact dimensions and a small dead volume.

Description:
FIELD OF THE INVENTION 
     The invention relates to a valve means and more particularly an amplifier comprising a housing, which contains a movable switching element having two closure portions each associated with the opening of a fluid duct and engaged at two spaced points by two actuating diaphragms, which are able to be subject to fluid so that the switching element is able to be positioned in at least two switching positions in which the respectively one duct opening is closed and the respectively other duct opening is open. 
     BACKGROUND OF THE INVENTION 
     Valve means of this type are customarily employed as pneumatic amplifiers, which are in a position to influence fluid flows with a high pressure and a high rate of flow using low control pressures. As far as the assignee is aware pneumatic amplifiers so far devised are characterized by having a plunger-like switching element having two closure portions adapted to close and open the opening of a respectively associated fluid duct in a manner dependent on the switching position of the switching element. The respective switching position is set by actuating diaphragms for engaging the switching element at two axially spaced points, and which as needed are subjected to a fluid acted upon by a control pressure. The switching over of valve means, which may be termed a diaphragm amplifier, takes place as part of a linear movement of the switching element. 
     It is considered to be a disadvantage of the valve means of this type that a reduction of the overall size and a standardization of the geometry thereof is only possible to a limited extent. The necessary arrangement of the ducts in the interior of the housing means that a certain minimum height is more or less necessary and can not be gone below. If various different amplifier functions are to be realized, then as a rule radical changes are necessary in the structure. 
     OBJECTS AND SUMMARY OF THE INVENTION 
     One object of the present invention is to create a valve means which has more compact dimensions and whose design is more readily adaptable. 
     In order to achieve this aim the switching element is constituted by a switching rocking member adapted to perform a pivotal movement on switching over, whose rocking arms placed on either side of the pivotal portion are engaged respectively by one of the actuating diaphragms and on which respectively one of the closure portions is provided. 
     It is in this manner that a valve means is provided, which may be manufactured with an extremely low, flat form, because on the one hand the actuating diaphragm and on the other hand the closure portions may be arranged, switching over no longer involving a linear movement but rather involves a pivoting or rocking movement of the rocker-like switching element which may consequently be termed a switching rocker member. The valve means may be employed in a relatively universal manner and is suitable, given a the correct geometry, more particularly as well in micro-actuators as a principal valve stage or in conjunction with other actuators as a high speed drive for valves having a large rated aperture or lumen. Moreover, the design in accordance with the invention favors a realization of the valve means in manufacturing methods in connection with micro-technology , because same are specifically suitable for the manufacture of flat, laminated structures. Finally the design of the invention favors the manufacture of valve means having different functions, because it is particularly in the case of an amplifier that there is the possibility of clearly separating the control plane and the power plane. 
     Further advantageous developments of the invention are defined in the dependent claims. 
     The switching rocker member and the actuating diaphragms are preferably accommodated in a common interior space in the housing. The housing itself may comprise several housing parts placed together as layers or lamellas, the two actuating diaphragms being held between the same housing parts. 
     The necessary pivotal movement of the rocking member could be predetermined exclusively by way of its attachment to the diaphragms, but however in order to ensure an exact switching function the invention preferably contemplates a pivotal support of the switching rocker member at its pivot portion. 
     A structure would be possible in which the actuating diaphragms only touch the switching rocker member. Presently a design is considered to be more convenient in which the actuating diaphragms are attached not only on the housing but also on the inherently rigid switching rocker member. 
     Both the actuating diaphragms and also the duct openings associated with the closure portions are preferably at least approximately at the same level as each other. 
     In order to produce an amplifier function in a particularly advantageous fashion there is preferably a provision such that the first and second fluid ducts associated with the closure portions and furthermore a third fluid duct communicate which are common connecting chamber, by way of which the fluid may be transferred, dependent on the switching position of the switching rocker member between the third fluid duct and one of the two other fluid ducts. Each of the two actuating diaphragms in this case preferably constitutes a movable wall between the connecting chamber and a control chamber, the two control chambers being separated from one another and each communicating with a control duct, by way of which the action of fluid on them may be set. In the case of such a structure it is frequently possible to alter the manner of functioning simply by changing the arrangement of the connections of the ducts, and for instance different types of amplifiers may be realized, which normally set a closed position or normally set an open position. 
     The actuating diaphragms may be designed with the same or different areas and in different sizes, forms and cross sections, it being possible to provide for preset deflections in the force-free state in order to influence the switching position of the switching rocker member. 
     The closure portions may be integrated in the switching rocker member or be in the form of separately applied sealing bodies. 
     In the case of the two actuating diaphragms it may be a question of individual diaphragms. However simpler manufacture and assembly is possible if the actuating diaphragms are united together in a common integral diaphragm element. 
     In what follows the invention will be described in detail with reference to the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a preferred embodiment of a valve means designed in the form of a pneumatic amplifier in a longitudinal section. 
     FIG. 2 shows a valve means of a comparable design to that of FIG. 1 in a highly diagrammatic longitudinal sectional view, there being one amplifier of the “normally open” type, which is illustrated in the open state. 
     FIG. 3 shows the valve means of FIG. 2 in the closed position of the rocking member. 
     FIG. 4 shows a valve means of an identical design to that of FIG. 2, in the case of which however a different fluid connection arrangement is provided so that there is a “normally closed” type, which is illustrated in the closed setting. 
     FIG. 4 a  shows a valve means of an identical design to that of FIG. 4, wherein the two actuating diaphragms have different areas. 
     FIG. 5 shows the valve means of FIG. 4 in the open position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Firstly the general structure of a preferred working embodiment of the valve means in accordance with the invention will be described with reference to FIG.  1 . 
     The valve means generally referenced  1  in the present case possesses a structure rendering possible use as a pneumatic amplifier. The valve means  1  is in this case divided up into several superposed planes functionally, that is to say in a first connection plane  2 , which is in the working example is on top, a control plane  3  arranged underneath it, a power plane  4  placed thereunder and a second connection plane  5  which is at the bottom. 
     The valve means  1  comprises a preferably block- or plate-like housing  6 , which is made up of a plurality of housing parts  7 ,  8  and  9  arranged as layers. The division up of the housing does not have to be the same as the illustrated division into planes. 
     The housing  6  contains an interior space  12 , in which a moving switching element is accommodated, which owing to its rocker-like design and manner of operation is referred to as a switching rocker member  13 . 
     Irrespectively of the alignment of the housing  6  adopted during operation the direction of the sequence of individual planes will be termed the height direction  14 , which in FIG. 1 is marked by a chained line. The switching rocker member  13  is so arranged inside the interior space  12  of the housing that it extends athwart the height direction  14  thereof, it possible having and angled longitudinal form. 
     The switching rocker member  13  has a pivotal portion  15  at its longitudinal middle point in the working example, at which it is so supported on the housing  6  in an articulating manner by way of a pivotal bearing means  16  that in relation to the housing  6  it may perform a pivotal movement  17  indicated by a double arrow, as part of which movement the rocker arms  18  and  18 ′, which extend in opposite directions away from the pivotal portion, are reciprocated like a see/saw. The pivotal bearing means  16  may be a fixed component of the housing  6  or it can be constituted by one or more separate parts, which are borne between the housing  6  and the pivotal portion  15  of the switching rocker member  13  and may be for instance like balls or corrugations in shape. First and second fluid ducts  22  and  23  open into the interior space  12  of the housing and their openings  24  and  25  are aligned in the vertical direction  14  and are surrounded by an annular valve seat. The valve seats  26  may be components of separate components inserted into the respective lower housing part  9 . Such a design offers the advantage that the valve seats may be made like jets or nozzles in a simple manner. Furthermore insert parts may be employed if required which have different diameters in order to provide different flow cross sections or lumens if required as part of modular system. 
     The arrangement is such that each opening  24  and  25  is opposite to one of the two switching rocker arms  18  and  18 ′. In the portion opposite to the respective opening  24  and  25  each switching rocker arms  18  and  18 ′ has a closure portion  27  and  27 ′ of suitable sealing material and more particularly of plastic material having rubber-elastic properties. 
     As related to the height direction  14  the duct openings  24  and  25  are preferably at the same level of the housing  6 , same being placed adjacent to each other and at a distance apart athwart the height direction  14 . Since the member  13  is slightly angled so that the rocker arms  18  and  18 ′ is so set at a small angle of under 180 degrees angle that its rocking arms  18  and  18 ′ make an obtuse angle at the top longitudinal side  28 , opposite to the closure portions  27  and  27 ′ it is possible for the switching rocker member  13  to be pivoted between two positions of rocking, in which, respectively. the one closure portion  27  and, respectively,  27 ′ closes the respective duct opening  24  and respectively  25 , by engagement with the associated valve seat  26 , while simultaneously the respectively other closure portion  27 ′ and  27  is lifted clear of the associated duct opening  25  and, respectively,  24  and permits fluid passage through the respective duct opening. The switching movement takes place like the movement of a swing or see-saw. 
     In the second connection plane the lower housing part  9  has a third fluid duct  32  extending through it, which at a suitable point also opens into the interior space  12  of the housing, the connection being open at all times. The associated duct opening  33  is preferably also aligned in the height direction  14  and may be located between the two other duct openings  24  and  25 . In the working embodiment it is opposite to the pivotal portion  15  in the height direction  14 . 
     The switching rocker member  13  is located in the power plane  4  in the portion, which in the working embodiment is the bottom portion, of the interior space  12  of the housing, which space will be henceforth termed the connection chamber  34 . Dependent on the particular position of switching of the switching rocker member  13  there is a fluid connection, extending through the connecting chamber  35 , between the third fluid duct  32  and the first or second fluid division  22  and  23 . 
     In the portion, adjoining the switching rocker member  13  in the height direction  14  adjacent to the top longitudinal side  28 , of the interior space  12  of the housing, which represent the control plane  3 , there are two actuating diaphragms  35  and  35 ′. In the working embodiment illustrated they consist of a polymeric plastic material and have rubber-like properties. The arrangement is such that opposite to each rocking arm  18  and  18 ′ on the longitudinal side  28  opposite to the respective the closure part  27  and  27 ′, there is one of the actuating diaphragms  35  and  35 ′. Thus the two actuating diaphragms  35  and  35 ′ engage the same longitudinal section of the switching rocker member  13 , on which furthermore one of the closure parts  27  and  27 ′ is provided, only on the opposite longitudinal side of the switching rocker member  13 . 
     It is preferred for the two actuating diaphragms  35  and  35 ′ to be adjacent each other as related to the height direction  14  in the control plane  3 . They respectively have outer surrounding peripheral edge part  36  attached to the housing  6  in a sealing manner. In the working embodiment illustrated in FIG. 1 this is because their surrounding peripheral edge part  36  is clamped between the top housing part  7  defining the first connection plane and a middle housing part  8  defining the control plane  3  in a firm manner. The two actuating diaphragms  35  and  35 ′ are consequently fixed between the same housing parts  7  and  8 , something substantially simplifying assembly. 
     The surrounding peripheral edge part  36  of the actuating diaphragms  35  and  35 ′ simultaneously constitutes the seal between the top and the middle housing parts  7  and  8 . The seal between the middle and the bottom housing parts  8  and  9  is produced in the working example by an intermediately placed annular seal  37  between these housing parts in the peripheral part of the interior space  12  of the housing. 
     It will be clear that the division of the housing  6  may be different to that illustrated and it would be more particularly possible to provide only two housing parts, which between them define the interior space  12  of the housing and between which the actuating diaphragms  35  and  35 ′ are clamped at the edge (comparable to the designs illustrated in FIGS.  2  through  5 ). 
     At their central portion  38  the actuating diaphragms  35  and  35 ′ engage respectively associated rocker arms  18  and  18 ′. In this respect a plain engagement by touching would be possible, but however the physical attachment adopted in the working example is recommended, which means that a respective central diaphragm part  38  and  38 ′ is at all times only movable jointly with the associated rocker arm  18  and  18 ′ irrespectively of the direction of pivoting of the switching rocker member  13 . In order to simplify assembly and any necessary dismounting it may here be a question of a releasable type of attachment. 
     The desired position of switching and/or switching movement of the switching rocker member  13  may be produced by ganged fluid operation of the actuating diaphragms  35  and  35 ′. Given a suitable operation by fluid the central diaphragm portions  38  and  38 ′ are caused to move generally in the height direction  14 , such movement being transmitted to the switching rocker member  13  with a thrusting or drawing effect. Because the central diaphragm portions  38  and  38 ′ are held by way of elastic intermediate portions  42  in a flexible manner on the surrounding peripheral edge portions  36 , during the pivoting or rocking movement of the switching rocker member  13  they readily allow for the small change in direction of the movement. 
     It is possible to provide the valve means with a spring means  47  indicated in chained lines in FIG. 2 for example, which bears against the housing  6  and the switching rocker member  13  and biases the switching rocker member  13  in a regular manner into a switching position representing the home position of the valve means. 
     The actuating diaphragms  35  and  35 ′ divide up the interior housing space  12  into the above mentioned connecting chamber  34  and into two control chambers  43  and  43 ′ associated with respectively one of the actuating diaphragms  35  and  35 ′. Each actuating diaphragm  35  and  35 ′ constitutes a fluid-tight, moving wall between the connecting chamber  34  and a control chamber  43  and  43 ′ arranged on the side opposite to the switching rocker member  13 . Each of the control chambers  43  and  43 ′ communicates with its own control duct  44  and  44 ′ extending in the first connection plane  2  and, in the working example, through the top housing part  7 . The control ducts  44  and  44 ′ open like the fluid ducts  22 ,  23  and  32  at their outer end at the outer face of the housing  2 , where there is the possibility of connecting up fluid ducts leading to other equipment. 
     In what follows a first preferred manner of operation of the valve means  1  will be described with reference to FIGS. 2 and 3, the diagrammatic drawings simultaneously indicating some possibilities of modification in the design structure of the valve means. 
     The fluid circuit diagram of the valve means  1  in accordance with FIGS. 2 and 3 is so selected that the first fluid duct  22  constitutes a venting duct, which is connected with a pressure sink and more particularly with the atmosphere R, whereas the second fluid duct  23  constitutes a supply duct, which is connected with a source P of pressure, which makes available a pressure medium, which is more especially gaseous and is subject to a working pressure. The third fluid duct  32  is a power duct which is able to be connected with a load A, as for instance a principal valve, which is to be controlled by the valve means  1  with a pilot function or a directly connected load. The first control duct  44 , which is associated with the first actuating diaphragm  35  cooperating with that rocker arm  18  which controls the opening of the first fluid duct  22 , constitutes a second venting duct, which like the first fluid duct  22 , is continuously connected with a pressure sink and is more particularly connected with the atmosphere, something which is indicated by the letter R′. The second control duct  44 ′ associated with the second control chamber  43 ′ and the second actuating diaphragm  35 ′. constitutes a principal control duct, which is connected with a control pressure source P s  able to supply a variable control pressure, at least two pressure values being possible in the present case, on the one hand the atmospheric pressure or pressure of the surroundings and on the other hand a pressure level corresponding to the power or working pressure. The action of the pressure is controlled by means of a valve (not illustrated) associated with the second control duct  44 ′. 
     The valve may be operated not only with a gaseous but also with hydraulic pressure medium. 
     FIG. 2 shows the home position of the valve means, in the case of which it is here a question of an open position, which is produced by the application of a control pressure of zero bar to the second control duct or, respectively, principal control duct  43 ′, that is to say the second control chamber  43 ′ is vented. The balance of forces occurring at the actuating diaphragms  35  and  35 ′ and the switching rocker member  13  then means that the switching rocker  13  is pivoted into a switching position, in which the connection between the venting duct  22  and the connecting chamber  34  is closed, whereas simultaneously the supply duct  23  communicates with the connecting chamber  34  owing to the closure portion  27 ′ being moved clear of its duct opening  25  so that the pressure medium at the lower pressure level may flow into the power duct  32  and consequently to a connected load A. 
     In order to vent the load A a higher control pressure is applied to the principal control duct  44 , such pressure being equal to the power pressure in the working example. The balance of forces now existing results in a rocking or pivotal motion of the switching rocker member  13  into the second switching position representing the opened position as indicated in FIG.  3 . The connection between the supply duct  23  and the connecting chamber  34  is interrupted here, whereas simultaneously the pressure medium may flow off from the load A by way of the connecting chamber  34  into the venting duct  22  constituted by the first fluid duct, because the closure portion  27  associated with latter is open. 
     All in all the valve means  1  is able to perform a {fraction (3/2)} valve function in the working example. 
     While in the working embodiment of FIGS. 2 and 3 the selected fluid circuit diagram means that there is a valve means of the “normally open” type, the working example of FIGS. 4 and 5 represents a valve means of the “normally closed” type owing to its slightly modified connection arrangement. 
     In the case of the working embodiment of FIGS. 4 and 5 the connection of the three fluid ducts  22 ,  23  and  32  of the power plane corresponds to that of the working example of the FIGS. 2 and 3. The changes in the fluid connections only relate to the control plane and, respectively, the two control ducts  44  and  44 ′. 
     Thus gage pressure is continuously present at the second control duct  44 ′ and accordingly in the associated second control chamber  43 ′ since there is a constant connection with a first source P′ of control pressure, the control pressure in the working example being equal to the power pressure present in the supply duct  23 . The volume of compressed air held in the control chamber  43 ′ consequently constitutes a pneumatic spring, which effects closure of the supply duct  23  as long as there is a control pressure of for example zero bar in the first control chamber  43  and, respectively, in the first control duct  44  connected with same. This is achieved because the first control duct  44  is connected with a second control pressure source P s , by way of which a control pressure with a variable pressure level may be supplied. If such control pressure is equal to the pressure of the atmosphere, the switching rocker member  13  will assume the closed position illustrated in FIG. 4, the supply duct  23  being closed and a connection being produced between the power duct  32  and the venting duct  22 . For switching over into the open position depicted in FIG. 5, the second control pressure source P s  produces a gage pressure in the first control chamber  43 , which gage pressure may be equal to the power pressure, something which results in a displacement of the balance of forces so that the switching rocker member  13  is pivoted in the open position, in which the three fluid ducts  22 ,  23  and  32  are connected together in the fashion already described with reference to FIG.  2 . 
     It will be seen that the valve means  1  renders possible a modification of the valve and amplifier functions which are possible without having perform substantial changes in design and in fact it is essentially sufficient to change the fluid connection of some valves. 
     FIGS. 2 through 5 furthermore serve to indicate that it is an advantage to arrange the outer duct openings of the first, second and third fluid ducts  22 ,  23  and  32 , provided on the outer side of the housing  6 , at least approximately at the same level perpendicular to the height direction  14  adjacent to one another. In a similar manner it is more particularly possible to arrange for the outer openings of the control ducts  44  and  44 ′, present on the outer side of the housing  6 , to be also at least approximately at the same level perpendicularly to the height direction  14  adjacent to each other. 
     In the case of the working examples of FIGS. 2 and 5 the two actuating diaphragms  35  and  35 ′ are in the form of mutually separate components. On the other hand in the case of the working example of FIG. 1 they are collected together integrally in a common diaphragm element  45 , something which simplifies manufacture and assembly. In both cases the actuating diaphragms are preferably manufactured at least in part of a rubber-like elastic material, at least in the elastic intermediate portions  42 , a polymer material being preferred. 
     An arrangement which is particularly readily assembled is produced if the switching rocker member  13 , the actuating diaphragms  35  and  35 ′ and the closure portions  27  and  27 ′ are united as a common element. 
     While in the working embodiment of FIG. 1 the pivotal bearing means  16  is provided adjacent to bottom longitudinal side  29  of the switching rocker member  13  opposite to the actuating diaphragms  35  and  35 ′, in the working examples of FIGS. 2 through 5 it is located adjacent to the top longitudinal side  28  of the switching rocker member  13  facing the actuating diaphragms  35  and  35 ′. To precisely set an exact range of pivoting it would however be possible as well to provide suitable guide means on the top side and also on the bottom side. Furthermore it would be feasible to ensure the desired switching over characteristic simply by the attachment of the switching rocker member  13  on the actuating diaphragms  35  and  35 ′ and to do without an additional supporting engagement of the pivotal portion on the housing. 
     Changes in the switching characteristic of the valve means may also be provided by having the diaphragms not of equal area as in the working example but with different areas, forms and/or cross sections, as shown in FIG. 4 a . It is furthermore possible to so design the actuating diaphragms that in the condition free of forces they retain the deflections imparted to them. 
     While in the working example of FIG. 1 the closure portions  27  and  27 ′ are set in the switching rocker member  13 , so that it is possible to speak of an integral construction, the working examples of FIGS. 2 through 5 as separate sealing bodies possess closure portions  27  and  27 ′ arranged on the corresponding longitudinal side of the switching rocker member  13 . 
     As already noted, the housing  6  in the working embodiment of FIG. 1 is divided into three housing parts  7 ,  8  and  9 , the clamping in place of the actuating diaphragms  35  and  35 ′ being between the top housing part  7  having the control ducts  44  and  44 ′ and the middle housing part  8  adjoining same. The middle housing part  8 , which may be termed an intermediate plate, ensures on the one hand a reliable sealing function between the control chambers  43  and  43 ′ and on the other hand facilitates working with different actuating diaphragms having different areas and/or being separate. 
     A particularly compact and flat design of the valve means  1  is more particularly ensured if the actuating diaphragms  35  and  35 ′ and the duct openings  24  and  25  controlled by the switching rocker member  13  are respectively arranged adjacent to each other in a perpendicular direction, the perpendicular direction extending athwart and more particularly at a right angle to the mutually parallel longitudinal axes  46  and  46 ′ of the duct openings  24  and  25 , such longitudinal axes being aligned in the same direction in the working example as the height direction  14 . 
     One advantage of the working examples is also that owing to the arrangement of the outer openings of the fluid ducts  22 ,  23  and  32  on the one hand and the control ducts  44  and  44 ′ on the other hand regular or defined points of intersection may be produced, which render possible the use of the valve means as a modular component in the form of a universal “insert”. Furthermore by different connection up of the control chambers  43  and  43 ′ with line, control and atmospheric pressure it is possible to ensure a simple attainment of different valve states without further modifications of the valve means. 
     In accordance with a convenient further development it is possible for the output volumetric to be varied in proportion to pressure in one of the two control chambers  43  and  43 ′ so that together with a suitable actuator element an indirectly operating or regulating valve may be produced. Furthermore there is the possibility of producing amplification of pressure by having two additional diaphragms placed in the power plane and having a smaller area than the above mentioned actuating diaphragms simultaneously with the amplification of quantity or rate. 
     Last but not least it is to be noted that the tension state or the position of one or more diaphragms may be utilized to detect the setting quantity, this being more particularly possible in the case of use of the valve means as an amplifier.