Abstract:
A compact, easily manufactured, axisymmetric mechanism can be configured to change the magnitude of a short-movement linear motion, or also reverse the movement direction, of an actuator for control of movable elements. The mechanism is bidirectional and reversible, functioning symmetrically, and does not contain any gears nor lead screw threads. It is constantly loaded, so that force change is achieved without mechanical backlash, introducing hysteresis. The movement conversion is generally proportional and suitable for use in actuating a fluid control valve intended for modulating the control of fluids.

Description:
This application claims the benefit under 35 U.S.C. 119(e) of the filing date of Provisional U.S. Application Ser. No. 61/685,116, entitled Multiflex Coupling, filed on Mar. 12, 2012, which is commonly owned and expressly incorporated herein by reference, in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related to a parallel motion mechanism with a circular shape that is well suited for use in axisymmetric devices like the modulating actuator of a proportional control valve. Various arrangements of the mechanism can change both the magnitude and direction of actuator motion. The movement conversion is generally proportional and suitable for use in actuating a fluid control valve. The invention is particularly useful in valves intended for proportional or modulating control of fluid delivery within industrial processes making semiconductor devices, pharmaceuticals, or fine chemicals, and many similar fluid delivery systems. 
     BACKGROUND OF THE INVENTION 
     The field of control valves intended for use within automated process control systems is broad and well known. Many proportional control valves have one or more movable elements that may be actively positioned, anywhere between an extreme open condition and an extreme closed condition, to adjust the flow of fluid passing therethrough. Fluid delivery apparatus intended for manipulating process materials within semiconductor manufacturing equipment usually require attention to the maintenance of high purity of the delivered reactants, and also are typically much smaller than valves used in petrochemical actuators are found in high purity instrumentation and control apparatus, such as mass flow controllers. U.S. Pat. No. 4,695,034 to Shimizu et al. describes the use of a stack of piezoelectric disc elements to effect movement of valve parts in a mass flow controller. U.S. Pat. No. 4,569,504 to Doyle describes the use of a magnetic solenoid with interleaved magnetic circuit elements. U.S. Pat. No. 5,660,207 to Mudd describes the use of a heated resistance wire that changes length with temperature changes in order to effect valve element movement. U.S. Pat. No. 6,178,996 to Suzuki describes the use of a pressurized fluid, such as nitrogen gas, to control the degree of opening of a diaphragm-operated control valve. All of the foregoing patents are herein expressly incorporated by reference, in their entirety. 
     One important disadvantage of both magnetic solenoid and thermal expansion type actuators is inherent constant power consumption when controlling valve elements positioned at an intermediate condition, such as when actively regulating fluid flow. A piezoelectric actuator is effectively a capacitor in an electrical circuit, and therefore does not consume current when an applied voltage is constant. Consequently, typical piezoelectric control valve applications only require low power and avoid the undesirable generation of heat found in electromagnetic actuators. A piezoelectric actuator advantageously may produce substantially more force than a solenoid actuator of comparable size, but achievable strain severely limits the distance a piezoelectric stack can move. Piezoelectric actuators nearly always are used in a manner wherein applying an activation voltage causes an extensional increase in the stack length (see the Shimizu et al. &#39;034 patent as well as U.S. Pat. No. 5,094,430 to Shirai et al., which is also herein expressly incorporated by reference, in its entirety). Shimizu et al. &#39;034 increases the available movement by interposing a force transmission member, comprising a plurality of radial lever-arm tongues, between the stack of piezoelectric disc elements and the moving portion of the control valve. The Shimizu force transmission members are complicated and difficult to manufacture correctly. Shirai et al. &#39;430 describe the use of a spherical bearing to couple movement from a stack of piezoelectric disc elements to other portions of the control valve to prevent adverse effects otherwise resulting from insufficient parallelism of parts. The use in the Shirai et al. system of a spherical bearing appears to preclude the use of Shimizu&#39;s force transmission member. Magnetic solenoid actuators nearly always affect driven element movement analogous to a decrease in length along the actuator axis (see Doyle &#39;504 for example), which is the opposite of piezoelectric actuator behavior. A consequence of these actuator differences is piezoelectric actuators being most likely associated with normally open valves (wherein applying power then causes the valve to decrease fluid flow) and magnetic solenoid actuators being most likely associated with normally closed valves (wherein applying power then causes the valve to increase fluid flow). A valve designer will benefit from having a mechanism to reverse the direction of actuator motion, or change the effective magnitude of actuator motion, to thereby allow both normally open and normally closed valves to use a single actuator type (piezoelectric, magnetic solenoid, pneumatic, etc.). 
     SUMMARY OF THE INVENTION 
     The present invention addresses the issues noted above, by providing a compact, easily manufactured system which can be configured to change the movement magnitude, or also reverse the movement direction, of an actuator for control of movable elements in a valve regulating fluid flow. The inventive mechanism is bidirectional and reversible, functioning symmetrically insofar as the naming conventions of “driving” and “driven”, “active” and “reactive”, and the like. The invention contemplates the use of linear motion force generators known to provide controlled, incremental movement as required in a proportional modulating valve. In a first configuration, the linear active direction motion (driving portion) from the force generator is reversed in direction to provide reactive direction motion (driven portion) having opposite direction. In a second configuration, the linear active direction motion (driving portion) from the force generator is typically doubled in magnitude to provide increased reactive direction motion (driven portion) in the same direction. The mechanism is referenced as a “multiflex coupling” because it can conveniently provide translational gain and direction change when used to couple an actuator to the movable portion of a valve. The mechanism does not contain any gears nor lead screw threads, and in usual practice is constantly loaded, so force change is achieved without mechanical backlash introducing hysteresis. The following direction may use notional directions (up and down, above and below, left and right, front and back, etc.) to assist understanding of relationships among the mechanism pieces, and the drawing figures generally match those notional directions or conventions, but it should be appreciated that an apparatus falling within the confines of the inventive concepts may attain any orientation in space, including actively translating or rotating or tumbling, without effect on the mechanism function. 
     In a typical embodiment, the mechanism is comprised of two disk-shaped elements (the driving-active and driven-reactive portions), two semicircular elements (rockers) that behave as levers, four link elements that connect the foregoing to each other, and nine pins that serve to hold together the elements, as well as an optional supporting sleeve. These various pieces may be made from a variety of materials, such as metals, plastics, composites, or ceramics, but heat treated tool steels, such as A2, D2, or H13 are considered appropriate to many applications, while aluminum alloys such as 6061 may also be used. In one embodiment, the disk-shaped active and reactive elements have an outside diameter of about 0.6 inches, outer dimensions of the semicircular rocker elements generally match the disk-shaped elements, and the mechanism has an axial length of about 0.5 inches. 
     The disk-shaped active and reactive elements in any mechanism configuration of the invention are each pierced by two symmetrically placed axial slots to accommodate the ends of two link elements. The axial slot locations might differ depending upon the specific translational multiplication (gain) desired from a particular mechanism. Each active and reactive element is also pierced by two lock pin holes that respectively intersect the axial slots accommodating link elements, which lock pin holes appear as symmetrically parallel cords of the element disk shape. The two semicircular rocker elements are identical within any particular mechanism configuration, as are the four links, while the active and reactive disk-shaped elements might be identical, or they may differ. Each semicircular rocker element is about the size of one-half of a disk-shaped active or reactive element, and is also pierced by two axial slots to accommodate the ends of two link elements. Each rocker element is also pierced by a radial pivot pin hole located on the half diameter perpendicular to the straight side of its semicircular shape and is additionally pierced by two lock pin holes, parallel to the pivot pin hole, that respectively intersect the axial slots accommodating links. 
     A complete mechanism assembly includes an upper disk-shaped element, two rocker elements placed side-by-side and below the upper disk, and a lower disk-shaped element under the rocker elements. A single pivot pin passes through the pivot pin hole of the two semicircular rocker elements and eight lock pins secure the ends of four links within respective axial slots in the several elements. Two links descend from the two axial slots of the upper disk-shaped element, and each link engages a corresponding axial slot in the below adjacent rocker element (one skilled in the art will note that the identical rocker elements appear as mirror images). Two additional links descend from the second axial slot of each rocker element and each link engages a corresponding axial slot in the below adjacent lower disk-shaped element. 
     Two disk-shaped active or reactive element variants may be combined with two semicircular rocker element variants to create mechanisms of the first configuration, providing three different direction-changing translational gains. Similarly, two disk-shaped active or reactive element variants may be combined with the two semicircular rocker element variants to create mechanisms of the second configuration providing three different direction preserving translational gains. Additional translational gain ratios clearly may be obtained by changing the rocker element variants, but the described easy permuting of parts is important for reduced manufacturing costs. 
     In accordance with one embodiment of the inventive mechanism, the pivot pin is made passive and held axially fixed relative to the bulk of an actuator, and extension of the actuator moves the active upper disk-shaped element axially away from the actuator bulk, while the reactive lower disk-shaped element of the mechanism retracts toward the actuator bulk. The axial movement of the active upper disk-shaped element is coupled to the rocker elements by the attached link pointing upwardly from each rocker. The rocker elements are thereby caused to slightly rotate about the pivot pin and downward motion of the one end of each rocker results in corresponding upward motion of the other end of each rocker. The reactive lower element translates axially in proportion to motion of the active upper element, but in an opposite direction. It will be appreciated that in this embodiment the active element is closer to the actuator bulk than is the reactive element, and the mechanism appears to lengthen. The passive pivot pin placed through pivot pin holes bored on a diameter of the side-by-side semicircular rocker elements may be conveniently held axially fixed by engaging similar diametrically opposite holes in a supporting sleeve or equivalent body surrounding the mechanism. The proportionality between motion of the active element and motion of the reactive element may be adjusted by choice of the separation between the lock pin holes and the pivot pin hole in the pair of rocker elements. 
     In accordance with another embodiment of the inventive mechanism, the upper disk-shaped element is made passive and held axially fixed relative to the bulk of an actuator, and extension of the actuator is coupled to the pivot pin that functions in an active manner, whereby extension of the actuator moves the active pivot pin axially away from the actuator bulk while the reactive lower disk-shaped element of the mechanism also extends away from the actuator bulk. One end of each rocker element is held axially fixed by the attached link pointing upwardly from each rocker coupled to the axially fixed upper disk-shaped passive element. Axial movement of the actuator displaces an active shaft that passes through the upper disk-shaped passive element, and engages the active pivot pin whereby axial movement of the active pivot pin is directly coupled to the rocker elements. The rocker elements are thereby caused to slightly rotate about the lock pin of the respective upwardly pointing link at one end of each rocker and downward motion of the middle of each rocker (imparted by the pivot pin) results in further downward motion of the other end of each rocker. The downward moving other end of each rocker is coupled to the reactive lower disk-shaped element by the attached link pointing downwardly from each rocker. The reactive lower element translates axially in proportion to motion of the active upper element in the same direction. It will be appreciated that in this embodiment the active element is closer to the actuator bulk than is the reactive element, and the mechanism appears to lengthen while the actuator also appears to lengthen. The upper disk-shaped passive element may be conveniently held fixed in a supporting sleeve or equivalent body surrounding the mechanism. The proportionality between motion of the active shaft and motion of the reactive element may be adjusted by choice of the separation between the lock pin holes and the pivot pin hole in the pair of rocker elements. 
     More particularly, there is provided a mechanical motion converter which comprises an active element, a reactive element, a pivot pin, and at least one rocker element for pivoting about the pivot pin. The rocker element is disposed axially between the active element and the reactive element. In operation, the active element, the reactive element, and the at least one rocker element are joined together and translate axially in response to a force exerted by an actuator. In the illustrated embodiments, each of the active element and the reactive element are disk-shaped. The at least one rocker element comprises a left rocker element and a right rocker element, wherein each of the rocker elements are pivotally supported by the pivot pin. In some illustrated embodiments, the pivot pin is passive, such that it is axially fixed within the mechanism. In other embodiments, the pivot pin is active, such that it is axially translatable relative to remaining portions of the mechanism. 
     Each of the rocker elements comprise an upward link and a downward link. In the illustrated embodiments, each of the links comprises a flat member having a hole therethrough and rounded ends. 
     Additional features of the inventive mechanical motion converter include a hole in each of the links, and a hole in each of the active element and the reactive element. A plurality of lock pins are provided for engaging corresponding holes in the links and the active and reactive elements to secure the active element, the links, and the reactive element together in a manner permitting relative axial movement of each joined component. The system further comprises a hole in each of the rocker elements for receiving one or more of the lock pins to further secure the active element, the links, and the active and reactive elements together. An axial slot is provided in each of the active element and the reactive element for receiving an end of a corresponding one of the links. Additionally, an axial slot is provided in each of the rocker elements, for receiving an opposing end of links extending from one of the active element and the reactive element. Preferably, each of the active element, the reactive element, and the left and right rocker elements comprise two axial slots for receiving lock pin ends. A flat disk spring is attached to an upper surface of the active element. 
     Each of the rocker elements comprises a hole for receiving the pivot pin and two holes for receiving lock pins, the two lock pin holes being disposed on opposed sides of the pivot pin hole. In some embodiments, the two lock pin holes on each rocker element are substantially identically spaced from the pivot pin hole, and axial movement of the active element is substantially equal to axial movement of the reactive element responsive to a force applied by an actuator. In other embodiments, the two lock pin holes on each rocker element are differently spaced from the pivot hole, and axial movement of the active element is greater than axial movement of the reactive element responsive to a force applied by an actuator, or, alternatively, axial movement of the active element is less than axial movement of the reactive element responsive to a force applied by an actuator. Additionally, in some embodiments, the active element and the reactive element move in the same axial direction responsive to a force applied by an actuator, while in other embodiments, the active element and the reactive element move in opposing axial directions responsive to a force applied by an actuator. These operational characteristics are selectable by the user, according to desired operational results, merely by designing or changing out certain components of the mechanical coupling system, as described in more detail below. 
     The invention, together with additional features and advantages thereof, may be best understood by reference to the following description taken in conjunction with the accompanying illustrative drawings. In these accompanying drawings, like reference numerals designate like parts throughout the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is an isometric perspective view of one embodiment of the inventive direction reversing mechanism, wherein the disk-shaped active element is upward and nearest to the actuator; 
         FIG. 1B  is an isometric perspective view revealing interior parts of the mechanism of  FIG. 1A  by illustrating some elements in phantom outline only; 
         FIG. 1C  is a top view of the mechanism of  FIG. 1A  in a first orientation; 
         FIG. 1D  is a top view similar to  FIG. 1C , wherein the mechanism has been rotated a predetermined distance in a counterclockwise direction; 
         FIG. 1E  is a cross-sectional view of the mechanism of  FIG. 1A , taken along the diametral line A-A of  FIG. 1C , showing the passive pivot pin cut along its length; 
         FIG. 1F  is a cross-sectional view of the mechanism of  FIG. 1A , taken along the diametral line B-B of  FIG. 1C , wherein the straight side of one semicircular rocker is shown; 
         FIG. 2  is an exploded view of the direction reversing mechanism of  FIG. 1D ; 
         FIG. 3A  is a perspective view of a portion of the mechanism of  FIG. 1A , axially sectioned along a cord bisecting the upward and downward links of a rocker element; 
         FIG. 3B  is a perspective view of the remaining portion of the mechanism of  FIG. 3A , revealing the second axial slot in the upper active element, wherein another link is engaged to couple with the other rocker element; 
         FIG. 4A  is an elevation view of the assembly of  FIG. 1A  illustrating the placement of lock pins relative to the fixed pivot pin for direction reversing motion and equal displacement (1.0:1.0 gain); 
         FIG. 4B  is an elevation view of another embodiment of the assembly (similar to  FIG. 1A ) illustrating the placement of lock pins relative to the fixed pivot pin for direction reversing motion and increased displacement (1.0:1.5 gain); 
         FIG. 4C  is an elevation view of yet another embodiment of the assembly (similar to  FIG. 1A ) illustrating the placement of lock pins relative to the fixed pivot pin for direction reversing motion and decreased displacement (1.5:1.0 gain); 
         FIG. 5A  is a sectioned view of the mechanism of  FIG. 5D  cleaved axially along diameter line A-A, wherein the active pivot pin is cut along its length and the active shaft is shown; 
         FIG. 5B  is a sectioned view of the mechanism of  FIG. 5D  cleaved axially along diameter line B-B wherein the active shaft is shown and the straight side of one semicircular rocker is illustrated; 
         FIG. 5C  is an isometric perspective view revealing interior parts of the mechanism of  FIG. 5D  by illustrating some elements in phantom outline only; 
         FIG. 5D  is a representative direction preserving mechanism illustrated in isometric perspective view with a disk-shaped passive element upward nearest to the actuator; 
         FIG. 6  is an exploded view of the direction-preserving mechanism of  FIG. 5D ; 
         FIG. 7A  is the representative mechanism of  FIG. 5D  axially sectioned along a cord bisecting the upward and downward links of a rocker element; 
         FIG. 7B  is the corresponding residual from  FIG. 7A  illustrating the second axial slot in the upper passive element, wherein another link is engaged to couple with the other rocker element; 
         FIG. 8A  is an elevation view of the assembly of  FIG. 5D , illustrating the placement of lock pins relative to the active pivot pin for direction-preserving motion with doubled displacement (1.0:2.0 gain); 
         FIG. 8B  is an elevation view of another embodiment of the assembly (similar to  FIG. 5D ) illustrating the placement of lock pins relative to the active pivot pin for direction preserving motion with increased displacement (1.0:2.5 gain); and 
         FIG. 8C  is an elevation view of yet another embodiment of the assembly (similar to  FIG. 5D ) illustrating the placement of lock pins relative to the active pivot pin for direction preserving motion and slightly decreased displacement (1.0:1.6 gain). 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now more particularly to the drawing figures, wherein like reference numerals designate identical or corresponding parts throughout the several views and embodiments, there is shown in  FIG. 1A  an embodiment of a direction reversing assembly  100  constructed in accordance with the principles of the present invention. The assembly  100  comprises a disk-shaped active element  120  disposed nearest to an actuator (not shown), typically for a valve, as discussed above, though other applications are within the scope of the invention as well. Directly below the disk-shaped active element  120  is a semicircular left rocker element  140  and an adjacent semicircular right rocker element  160 , both of which are supported by a passive pivot pin  190 . Directly below the rocker elements  140 ,  160  is a disk-shaped reactive element  180  nearest to movable elements of a valve (not shown) to be actuated. The mechanism assembly  100  may be fabricated of a variety of materials, such a metals, plastics, composites, or ceramics, but heat-treated tool steels, such as A2, D2, or H13, or a heat-treated stainless steel having spring-like characteristics, such as 17-4PH alloy, are considered appropriate to many applications, while aluminum alloys such as 6061 may also be used. The direction-reversing mechanism assembly  100  of the embodiment shown in  FIG. 1A  may, in one particular application, have an outside diameter of about 0.6 inch with an axial length of about 0.5 inch, and may optionally be surrounded by a sleeve  101 , which is represented using phantom lines in  FIG. 1A . 
     Mechanical action of the direction reversing mechanism assembly  100  may be understood by appreciating that slight rotation of a rocker element  140 ,  160  about the passive pivot pin  190  results in one end of the rocker element moving upwardly toward the active element  120 , while simultaneously the other end of the same rocker element moves downwardly toward the reactive element  180 . Appropriate mechanical coupling of one end of each rocker element  140 , 160  to the active element  120 , in combination with similar mechanical coupling of the corresponding other end of each rocker element  140 ,  160  to the reactive element  180 , causes the active element  120  and reactive element  180  to move in opposing directions. The mechanical coupling of the active element, two rocker elements  140 ,  160 , and the reactive element  180  will be further described below, in conjunction with a review of additional drawing figures. 
     A typical approach for coupling the rocker elements  140 ,  160  to the active element  120  and the reactive element  180  is by use of links and lock pins. For convenience of identification only, links connecting the rocker elements  140 ,  160  to the active element  120  are referred to as upward links  142 ,  166  ( FIG. 1A ), while links connecting rocker elements  140 ,  160  to the reactive element  180  are referred to as downward links  144 ,  168  ( FIG. 1B ). Upward links  142 ,  166  and downward links  144 ,  168  may be of various shapes (circular or rectangular cross-section, for example), but a simple flat part with circular holes through the thin dimension, and rounded ends about those holes, is conveniently manufactured. To preserve symmetry and proper function of the direction-reversing mechanism assembly  100 , upward links  142 ,  166  are generally identical and downward links  144 ,  168  are generally identical, but the upward links may differ in configuration and appearance from the downward links. With reference particularly to  FIG. 2 , it can be seen that the upward link  142  has a hole  146  therethrough, the upward link  166  has a hole  162  therethrough, the downward link  144  has a hole  148  therethrough, and the downward link  168  has a hole  164  therethrough. Corresponding lock pins  132 ,  176 ,  134 , and  178  are arranged for insertion into holes  146 ,  162 ,  148 , and  164 , respectively, for effecting connection between a link and an appropriate element of the direction reversing mechanism assembly  100 . 
     Continuing with reference particularly to  FIG. 2 , the upper disk-shaped active element  120  is pierced by two axial slots  122 ,  126  located in mirror symmetry about the center of the active element  120 . A left axial slot  122  is located, for example, forward and to the left of the disk center, while a right axial slot  126  is placed in the mirrored location rearward and to the right of the disk center. The axial slots  122 ,  126  are shaped and configured to receive ends of the upward links  142 ,  166  that project from the left and right rocker elements  140 ,  160  positioned below the active element  120 . Each axial slot  122 ,  126  is intersected by a corresponding lock pin hole  121 ,  125 , respectively, with the lock pin holes being geometric cords parallel to the diameter of symmetry within the active element disk shape  120 . Each axial slot  122 ,  126  and the end of the corresponding upward link  142 ,  166 , respectively, mate in a manner that allows the upward links  142 ,  166  to move easily about the inserted lock pins  132 ,  176 , respectively. The lock pins  132 ,  176  are inserted through the lock pin holes  121 ,  125 , respectively, of the active element  120  and the upper hole  146 ,  162 , respectively, of each upward link  142 ,  166 . Friction between the wall of an axial slot  122 ,  126  and the face of a flat upward link  142 ,  166 , respectively, may be minimized by providing narrow inward facing projections  123 ,  124 ,  127 ,  128  as shown in  FIGS. 1A and 2 , on opposing walls of the axial slots  122 ,  126 , whereby the projections serve as bearing surfaces. A chamfered cavity  129  may be provided in the upper surface of the active element  120  to receive a thrust ball (not shown) to compensate for possible misalignment with an actuator (not shown). 
     Still with reference primarily to  FIG. 2 , the lower disk-shaped reactive element  180  has a profile essentially identical to the upper disk-shaped active element  120 , while being of approximately the same thickness. The lower disk-shaped reactive element  180  is pierced by two axial slots  184 ,  188  located in mirror symmetry about the center of the reactive element. A right axial slot  188  is located, for example, forward and to the right of the disk center, while a left axial slot  184  is placed in the mirrored location rearwardly to and to the left of the disk center. The axial slots  184 ,  188  are shaped and configured to receive ends of the downward links  144 ,  168  that project from the left and right rocker elements  140 ,  160 , respectively, positioned above the reactive element  180 . Each axial slot  184 ,  188  is intersected by a corresponding lock pin hole  183 ,  187 , respectively, with the lock pin holes being geometric cords parallel to the diameter of symmetry within the reactive element disk shape  180 . Each axial slot  184 ,  188  and the end of the corresponding downward link  144 ,  168 , respectively, mate in a manner that allows the downward links  144 ,  168  to move easily about inserted lock pins  134 ,  178 . The lock pins  134 ,  178  are inserted through the lock pin holes  183 ,  187  of the reactive element  180  and the lower hole  148 ,  164  of each downward link  144 ,  168 . Friction between the wall of an axial slot  184 ,  188  and the face of a flat downward link  144 ,  168 , respectively, may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. One or more threaded holes  189  may be provided in the reactive element  180  to provide connection with valve moving parts (not shown). 
     The left rocker element  140  is semicircular in shape and has a profile essentially identical to one half of the upper disk-shaped active element  120 . It is also of approximately the same axial thickness. The left rocker element  140  is pierced through radially by a pivot pin hole  149  that bisects the semicircular shape. The left rocker element  140  is axially pierced by a front axial slot  141  which is shaped to receive an end of the front left upward link  142  and located coincident with the above positioned left axial slot  122  of the active element  120  above. The front axial slot  141  is intersected by a front lock pin hole  143 , wherein the front lock pin hole is parallel to the pivot pin hole  149 . The coincident location of the front axial slot  141  and the above left axial slot  122  allows coupling of the left rocker element  140  and the active element  120  by the front left upward link  142  using a first lock pin  133  inserted through the link  142 , and the left rocker front lock pin hole  143  along with a second lock pin  132  inserted through the link upper hole  146  and the active element left lock pin hole  121 . Additionally, the left rocker element  140  is axially pierced by a rear axial slot  147  shaped to receive an end of the rear left downward link  144  and located coincident with the below positioned left axial slot  184  of the reactive element  180  below. The rear axial slot  147  is intersected by a rear lock pin hole  145 , wherein the rear lock pin hole is parallel to the pivot pin hole  149 . The coincident location of the rear axial slot  147  and the below positioned left axial slot  184  allows coupling of the left rocker element  140  and the reactive element  180  by the rear left, downward link  144  using a third lock pin  135  inserted through the link  144  and the left rocker rear lock pin hole  145 , along with a fourth lock pin  134  inserted through the link lower hole  148  and the reactive element left lock pin hole  183 . The distance between the rocker element front lock pin hole  143  and the pivot pin hole  149  may differ from the distance between the rocker element rear lock pin hole  145  and the pivot pin hole  149 . Friction between the wall of an axial slot  141 ,  147  in the left rocker element and the face of a flat link  142 ,  144  may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. 
     The right rocker element  160  is semicircular in shape having a profile essentially identical to one half of the upper disk-shaped active element  120  and being of approximately the same axial thickness. The right rocker element  160  is pierced through radially by a pivot pin hole  169  that bisects the semicircular shape. The right rocker element  160  is axially pierced by a front axial slot  161  shaped to receive an end of the front right downward link  168  and located coincident with the below positioned right axial slot  188  of the reactive element  180  below. The front axial slot  161  is intersected by a front lock pin hole  167 , wherein the front lock pin hole is parallel to the pivot pin hole  169 . The coincident location of the front axial slot  161  and the below positioned right axial slot  188  allows coupling of the right rocker element  160  and the reactive element  180  by the front right downward link  168  using a fifth lock pin  177  inserted through the link  168  and the right rocker front lock pin hole  167 , along with a sixth lock pin  178  inserted through the link lower hole  164  and the reactive element right lock pin hole  187 . Additionally, the right rocker element  160  is axially pierced by a rear axial slot  163  shaped to receive an end of the rear right upward link  166  and located coincident with the above positioned right axial slot  126  of the active element  120  above. The rear axial slot  163  is intersected by a rear lock pin hole  165 , wherein the rear lock pin hole is parallel to the pivot pin hole  169 . The coincident location of the rear axial slot  163  and the above positioned right axial slot  126  allows coupling of the right rocker element  160  and the active element  120  by the rear right upward link  166  using a seventh lock pin  176  inserted through the link upper hole  162  and the active element right lock pin hole  125 , along with an eighth lock pin  175  inserted through the link  166  and the rocker element rear lock pin hole  165 . The distance between the rocker element front lock pin hole  167  and the pivot pin hole  169  may differ from the distance between the rocker element rear lock pin hole  165  and the pivot pin hole  169 . Friction between the wall of an axial slot  161 ,  163  in the right rocker element and the face of a flat link  168 ,  166  may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. 
     The supporting sleeve  101  is typically held in a fixed location by steps, flanges, or other structures in a valve assembly (not shown). The inside diameter of the supporting sleeve  101  is slightly greater than the outside diameter of the active element  120 , the rocker elements  140 ,  160 , and the reactive element  180  so the coupled elements may be fit inside the support sleeve  101  with sufficient clearance to allow motion of the elements. The outside diameter and length of the supporting sleeve  101  may be chosen according to convenience related to other structures in a valve assembly (not shown). The passive pivot pin  190  passes through diametrically opposite pivot pin holes  108 ,  109  that radially pierce the supporting sleeve  101 , or alternatively suitable features may be provided in a valve assembly to hold the passive pivot pin  190  in a fixed axial location without a supporting sleeve. The passive pivot pin  190  also simultaneously passes through the pivot pin hole  149  of the left rocker element  140  and passes through the pivot pin hole  169  of the right rocker element  160 . Consequently, the passive pivot pin  190  locates the rocker element pivot pin holes  149 ,  169  axially fixed relative to an actuator (not shown) secured in the valve assembly. While it is imperative that the left and right rocker elements  140 ,  160  must be free to rotate independently about the passive pivot pin  190 , designers skilled in the art may choose to make the passive pivot pin  190  fit snugly into supporting sleeve pivot pin holes  108 ,  109  ( FIGS. 1A ,  1 E) or may choose other methods for retaining the passive pivot pin, such as clips. 
     Actuator force applied to the chamfered cavity  129 , or otherwise communicated to the active element  120 , is immediately transferred to the rocker elements  140 ,  160  by the upward links  142 ,  166  whereby rotation of the rocker elements  140 ,  160  about the fixed passive pivot pin  190  then reverses the motion direction, and the reversed motion is transferred to the reactive element  180  by the downward links  144 ,  168 . The active element  120  is coupled to the front left upward link  142  by the second lock pin  132  inserted through the link upper hole  146  and the active element left lock pin hole  121 . Consequently, downward motion of the active element  120  causes downward motion of the front left upward link  142 , thereby pushing downward the first lock pin  133  and the left rocker front lock pin hole  143 . This action forces the front portion of the left rocker element  140  to move downward as the left rocker element  140  undergoes a slight rotation about the passive pivot pin  190 . The slight rotation of the left rocker element  140  causes the rear portion of the left rocker element  140  to move upwardly, thereby pushing upward the left rocker rear lock pin hole  145  and the third lock pin  135 . This action forces the rear left downward link  144  to move upwardly as well. The rear left downward link  144  is coupled to the reactive element  180  by the fourth lock pin  134  inserted through the link lower hole  148  and the reactive element left lock pin hole  183 . Consequently, upward motion of the rear left downward link  144  imparts upward motion to the reactive element  180 . The active element  120  is also coupled to the rear right upward link  166  by the seventh lock pin  176  inserted through the link upper hole  162  and the active element right lock pin hole  125 . Consequently, downward motion of the active element  120  causes downward motion of the rear right upward link  166 , thereby pushing downward the eighth lock pin  175  and the right rocker rear lock pin hole  165 , thus forcing the rear portion of the right rocker element  160  to move downwardly as the right rocker element  160  undergoes a slight rotation about the passive pivot pin  190 . The slight rotation of the right rocker element  160  causes the front portion of the right rocker element  160  to move upwardly, thereby pushing upwardly the right rocker front lock pin hole  167  and the fifth lock pin  177 . This action forces the front right downward link  168  to move upward as well. The front right downward link  168  is coupled to the reactive element  180  by the sixth lock pin  178  inserted through the link lower hole  164  and the reactive element right lock pin hole  187 . Consequently, upward motion of the front right downward link  168  imparts upward motion to the reactive element  180 . The foregoing explains how downward motion of the active element  120  is translated into opposite (upward) motion of the reactive element  180 . 
     Those skilled in the art may appreciate the need to avoid undesirable friction by keeping the active element  120  centered inside the supporting sleeve  101 . Parallel motion devices like the direction reversing mechanism assembly  100  can allow the active element  120  to tip and cease being perpendicular to the mechanism central axis whereby undesirable friction also may occur. A flat disk spring  107  attached to the upper surface of the active element  120  and extending to contact the end of the support sleeve  101  is a convenient approach for preventing undesirable friction. The flat disk spring  107  may be attached to the active element  120  by welding, adhesive, small threaded fasteners, or other suitable means. 
     The left rocker element  140  and right rocker element  160  are substantially identical in the illustrated embodiment, and merely rotated by 180 degrees about the direction reversing mechanism central axis. Thus, the rocker lock pin holes  143 ,  165 , enabling connection to the upward links  142 ,  166 , are identically spaced from the pivot pin holes  149 ,  169 . Similarly, the other rocker lock pin holes  145 ,  167 , enabling connection to the downward links  144 ,  168 , also are identically spaced from the pivot pin holes  149 ,  169 , though that spacing distance may be different than is the case for the rocker lock pin holes  143 ,  165 . The ratio of these distances establishes the specific translational multiplication (gain) available from a particular direction reversing mechanism assembly  100 . Representative dimensions and resulting movement ratios are shown in Table 1 and illustrated in  FIGS. 4A ,  4 B, and  4 C. Retention of the eight lock pins may be accomplished by providing a snug fit in the holes of link elements, or a snug fit in the lock pin holes in the various full and partial disk-shaped elements, or a suitable combination of these or other choices (e.g. threads, adhesive, staking, etc.), as optimized for particular manufacturing methods. 
     The previously described first representative example of a direction-reversing mechanism assembly  100 , illustrated in  FIGS. 1A-1F ,  2 ,  3 A, and  3 B, has the same distance between the pivot pin holes  149 ,  169  and the rocker front lock pin holes  143 ,  167  versus the rocker rear lock pin holes  145 ,  165 , as noted above. As may be seen in  FIG. 4A , the lock pin hole placement in the rocker elements is symmetrical. However, in a second representative embodiment of a direction reversing mechanism, as illustrated in  FIG. 4B , rocker elements  240 ,  260  in this second embodiment have lock pin holes that are not symmetrically disposed with respect to the corresponding pivot pin holes. The rear left lock pin hole  245  and the front right lock pin hole  267  are the same distance from the corresponding pivot pin holes  249 ,  269  as in the first embodiment, and thus make the downward link locations suitable for coincident matching with axial slots  184 ,  188  in the same reactive element  180 . The front left lock pin hole  243  and the rear right lock pin hole  265 , however, are disposed at a smaller distance from the corresponding pivot pin holes  249 ,  269  compared to the first embodiment and thus make the upward link locations different as well. A different active element  220  must be used, having axial slots properly placed to intercept the upward links, for the second embodiment. The ratio of the smaller upward link separation compared to the previous distance in the first embodiment makes the second embodiment rocker elements  240 ,  260  function as levers that impart more reversed motion to the reactive element than the actuator imparts to the active element. 
     A third embodiment of the direction reversing assembly of the invention is shown in  FIG. 4C . In this embodiment, the rocker elements  340 ,  360  have lock pin holes that are not symmetrically disposed with respect to the corresponding pivot pin holes. The rear left lock pin hole  345  and the front right lock pin hole  367  are a smaller distance from the corresponding pivot pin holes  349 ,  369  compared to the previous first and second embodiments and thus make the downward link locations different as well. A different reactive element  380  must be used, having axial slots properly placed to intercept the downward links, for the third embodiment of  FIG. 4C . The front left lock pin hole  343  and the rear right lock pin hole  365  are placed at the same distance from the corresponding pivot pin holes  349 ,  369  as in the first embodiment, and thus make the upward link locations suitable for coincident matching with axial slots  124 ,  128  in the same first embodiment active element  120 . The ratio of the smaller downward link separation compared to the previous distance makes the third embodiment rocker elements  340 ,  360  function as levers that impart less reversed motion to the reactive element than the actuator imparts to the active element. 
     
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 Direction 
                 left rocker element 
                 left rocker element 
                 left rocker ratio 
                 right rocker element 
                 right rocker element 
                 right rocker ratio 
                   
               
               
                 Reversing 
                 front lock pin hole 
                 rear lock pin hole 
                 of active element 
                 front lock pin hole 
                 near lock pin hole 
                 of active element 
               
               
                 Mechanism 
                 (upward link) to 
                 (downward link) to 
                 connection to 
                 (downward link) to 
                 (upward link) to 
                 connection to 
                 ratio of 
               
               
                 Assembly 
                 pivot pin hole 
                 pivot pin hole 
                 reactive element 
                 pivot pin hole 
                 pivot pin hole 
                 reactive element 
                 reversed 
               
               
                 Figure 
                 spacing 
                 spacing 
                 connection 
                 spacing 
                 spacing 
                 connection 
                 motion 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 4A 
                 0.165″ 
                 0.165″ 
                 1.0 
                 0.165″ 
                 0.165″ 
                 1.0 
                 1.0 
               
               
                 4B 
                 0.110″ 
                 0.165″ 
                 0.67 
                 0.165″ 
                 0.110″ 
                 0.67 
                 1.5 
               
               
                 4C 
                 0.165″ 
                 0.110″ 
                 1.5 
                 0.110″ 
                 0.165″ 
                 1.5 
                 0.67 
               
               
                   
               
             
          
         
       
     
     A first representative embodiment of a movement increasing mechanism assembly  500  constructed in accordance with the principles of the present invention is illustrated in  FIG. 5D . The assembly  500  has an upward directed axially centered active shaft  505  for coupling force from an actuator (not shown). The active shaft  505  passes through a centered axial hole  529  that pierces a disk-shaped passive element  520  comprising the uppermost portion of the movement increasing mechanism assembly  500 . Directly below the disk-shaped passive element  520  is a semicircular left rocker element  540  and an adjacent semicircular right rocker element  560 . Both of the rocker elements  540 ,  560  are simultaneously situated upon an active pivot pin  590 . The rocker elements  540 ,  560  additionally have axially centered semicircular reliefs  504 ,  506  (making each rocker element similar to one half of a wide ring shape) ( FIG. 6 ) which allow the active shaft  505  to also engage the active pivot pin  590 . Directly below the rocker elements  540 ,  560  is a disk-shaped reactive element  580  nearest to movable elements of a valve (not shown). One end of each rocker element is coupled to the passive element  520  while the other end of each rocker element is coupled to the reactive element  580 . The mechanism assembly  500  may be made from a variety of materials, such as metals, plastics, composites, or ceramics, but heat treated tool steels, such as A2, D2 or H13, or a heat treated stainless steel having spring-like characteristics, such as 17-4PH alloy, are considered appropriate to many applications, while aluminum alloys such as 6061 may also be used. The movement increasing mechanism assembly  500  of the illustrated embodiment has an outside diameter of about 0.6 inch with an axial length of about 0.5 inch and may be optionally surrounded by a supporting sleeve  501  that is illustrated using phantom lines in  FIG. 5D . 
     The mechanical coupling of the passive element  520 , two rocker elements  540 ,  560 , and the reactive element  580  will be described further in connection with discussion of  FIGS. 5A ,  5 B,  5 C,  5 D,  6 ,  7 A, and  7 B. A typical means for coupling the rocker elements  540 ,  560  to the passive element  520  and the reactive element  580  is by the use of links and lock pins, as in the prior embodiments. For convenience of identification only, links connecting rocker elements  540 ,  560  to the passive element  520  are referred to as upward links  542 ,  566 , while links connecting rocker elements  540 ,  560  to the reactive element  580  are referred to as downward links  544 ,  568 . Upward links  542 ,  566  and downward links  544 ,  568  may be of various shapes (circular or rectangular cross-section, for example), but a simple flat part with circular holes through the thin dimension, and rounded ends about those holes, is conveniently manufactured. To preserve symmetry and proper function of the movement increasing mechanism assembly  500 , upward links  542 ,  566  are generally identical and downward links  544 ,  568  are generally identical, but upward links may differ in configuration from downward links. Links have an upper hole  546 ,  562  and a lower hole  548 ,  564  through which corresponding lock pins  532 ,  576 ,  534 ,  578 , respectively, are inserted to effect connection between a link and an appropriate element of the movement increasing mechanism assembly  500 . 
     Mechanical action of the movement increasing mechanism assembly  500  may be understood by appreciating that downward movement of the active pivot pin  590  will cause slight rotation of a rocker element  540 ,  560  about an axially fixed lock pin  533 ,  575  that couples one end of the rocker element to an upward link  542 ,  566 . The slight rotation results in further downward motion of a lock pin  535 ,  577  that couples the other end of the same rocker element to a downward link  544 ,  568 , moving that link downward toward the reactive element  580 . Appropriate mechanical coupling of one end of each rocker element  540 ,  560  to the passive element  520 , in combination with similar mechanical coupling of the corresponding other end of each rocker element  540 ,  560  to the reactive element  580 , thus causes increased movement of the reactive element  580 . Upward movement of the active pivot pin  590  will of course result in a corresponding increased upward movement of the reactive element  580 . 
     The upper disk-shaped passive element  520  is pierced by two axial slots  522 ,  526  located in mirror symmetry about the center of the passive element. A left axial slot  522  is located, for example, forward and to the left of the disk center, while a right axial slot  526  is placed in the mirrored location rearward and to the right of the disk center. The axial slots  522 ,  526  are shaped to receive ends of upward links  542 ,  566  that project from the left and right rocker elements  540 ,  560  positioned below the passive element  520 . Each axial slot  522 ,  526  is intersected by a corresponding lock pin hole  521 ,  525 , with the lock pin holes being geometric cords parallel to the diameter of symmetry within the passive element disk shape  520 . Each axial slot  522 ,  526  and the end of the corresponding upward link  542 ,  566  mate in a manner that allows the upward links  542 ,  566  to move easily about the inserted lock pins  532 ,  576 . The lock pins are inserted through the lock pin holes  521 ,  525  of the passive element  520  and the upper hole  546 ,  562  of each upward link  542 ,  566 . Friction between the wall of an axial slot  522 ,  526  and the face of a flat upward link  542 ,  566  may be minimized by providing narrow inward facing projections  523 ,  524 ,  527 ,  528  on opposing walls of the axial slot  522 ,  526  whereby the projections serve as bearing surfaces. The upper disk-shaped passive element  520  is additionally pierced by the centered axial hole  529  through which passes the upward directed axially centered active shaft  505 . The active shaft  505  is radially pierced by a diametrical shaft pin hole  508  which engages the active pivot pin  590  to transmit force from an actuator (not shown). A chamfered cavity  509  may be provided in the upper end surface of the active shaft  505  to receive a thrust ball (not shown) to compensate for possible misalignment with the actuator. 
     The lower disk-shaped reactive element  580  has a profile similar to the upper disk-shaped passive element  520 , but of smaller external diameter, while being of approximately the same thickness. The reactive element  580  is pierced by two axial slots  584 ,  588  located in mirror symmetry about the center of the reactive element. A right axial slot  588  is located, for example, forward and to the right of the disk center while a left axial slot  584  is placed in the mirrored location rearwardly and to the left of the disk center. The axial slots  584 ,  588  are shaped to receive ends of downward links  544 ,  568  that project from the left and right rocker elements  540 ,  560  positioned above the reactive element  580 . Each axial slot  584 ,  588  is intersected by a corresponding lock pin hole  583 ,  587 , with the lock pin holes being geometric cords parallel to the diameter of symmetry within the reactive element disk shape  580 . Each axial slot  584 ,  588  and the end of the corresponding downward link  544 ,  568  mate in a manner that allows the downward links  544 ,  568  to move easily about inserted lock pins  534 ,  578 . The lock pins  534 ,  578  are inserted through the lock pin holes  583 ,  587  of the reactive element  580  and the lower hole  548 ,  564  of each downward link  544 ,  568 . Friction between the wall of an axial slot  584 ,  588  and the face of a flat downward link  544 ,  568  may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. One or more threaded holes  589  may be provided in the reactive element  580  to provide connection with valve moving parts (not shown). 
     The left rocker element  540  is semicircular in shape, having a profile similar to one half of the upper disk-shaped passive element  520 , but of smaller external diameter while being of approximately the same axial thickness. The left rocker element  540  is pierced through radially by a pivot pin hole  549  that bisects the semicircular shape. The left rocker element  540  is axially pierced by a front axial slot  541  shaped to receive an end of the front left upward link  542  and located coincident with the above positioned left axial slot  522  of the passive element  520  above. The front axial slot  541  is intersected by a front lock pin hole  543  wherein the front lock pin hole is parallel to the pivot pin hole  549 . The coincident location of the front axial slot  541  and the above positioned left axial slot  522  allows coupling of the left rocker element  540  and the passive element  520  by the front left upward link  142  using a first lock pin  533  inserted through the link  542  and the left rocker front lock pin hole  543  along with a second lock pin  532  inserted through the link upper hole  546  and the passive element left lock pin hole  521 . Additionally, the left rocker element  540  is axially pierced by a rear axial slot  547  shaped to receive an end of the rear left downward link  544  and located coincident with the below positioned left axial slot  584  of the reactive element  580  below. The rear axial slot  547  is intersected by a rear lock pin hole  545 , wherein the rear lock pin hole is parallel to the pivot pin hole  549 . The coincident location of the rear axial slot  547  and the below positioned left axial slot  584  allows coupling of the left rocker element  540  and the reactive element  580  by the rear left downward link  544  using a third lock pin  535  inserted through the link  544  and the left rocker rear lock pin hole  545  along with a fourth lock pin  534  inserted through the link lower hole  548  and the reactive element left lock pin hole  583 . The distance between the rocker element front lock pin hole  543  and the pivot pin hole  549  may differ from the distance between the rocker element rear lock pin hole  545  and the pivot pin hole  549 . Friction between the wall of an axial slot  541 ,  547  in the left rocker element and the face of a flat link  542 ,  544  may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. The left rocker element  540  additionally has an axially centered semicircular relief  504  (making the rocker element similar to one half of a wide ring shape) which allows the active shaft  505  to also engage the active pivot pin  590  which passes through the pivot pin hole  549 . 
     The right rocker element  560  is semicircular in shape and has a profile similar to one half of the upper disk-shaped passive element  520 , but of smaller external diameter while being of approximately the same axial thickness. The right rocker element  560  is pierced through radially by a pivot pin hole  569  that bisects the semicircular shape. The right rocker element  560  is axially pierced by a front axial slot  561  shaped to receive an end of the front right downward link  568  and located coincident with the below positioned right axial slot  588  of the reactive element  580  below. The front axial slot  561  is intersected by a front lock pin hole  567 , wherein the front lock pin hole is parallel to the pivot pin hole  569 . The coincident location of the front axial slot  561  and the below positioned right axial slot  588  allows coupling of the right rocker element  560  and the reactive element  580  by the front right downward link  568  using a fifth lock pin  577  inserted through the link  568  and the right rocker front lock pin hole  567  along with a sixth lock pin  578  inserted through the link lower hole  564  and the reactive element right lock pin hole  587 . Additionally, the right rocker element  560  is axially pierced by a rear axial slot  563  shaped to receive an end of the rear right upward link  566  and located coincident with the above positioned right axial slot  526  of the passive element  520  above. The rear axial slot  563  is intersected by a rear lock pin hole  565  wherein the rear lock pin hole is parallel to the pivot pin hole  569 . The coincident location of the rear axial slot  563  and the above positioned right axial slot  526  allows coupling of the right rocker element  560  and the passive element  520  by the rear right upward link  566  using a seventh lock pin  576  inserted through the link upper hole  562  and the active element right lock pin hole  525 , along with an eighth lock pin  575  inserted through the link  566  and the rocker element rear lock pin hole  565 . The distance between the rocker element front lock pin hole  567  and the pivot pin hole  569  may differ from the distance between the wall of an axial slot  561 ,  563  in the right rocker element rear lock pin hole  565  and the pivot pin hole  569 . Friction between the wall of an axial slot  561 ,  563  in the right rocker element and the face of a flat link  568 ,  566  may be minimized by providing narrow inward facing projections on opposing walls of the axial slot whereby the projections serve as bearing surfaces. The right rocker element  560  additionally has an axially centered semicircular relief  506  (making the rocker element similar to one half of a wide ring shape), which allows the active shaft  505  to also engage the active pivot pin  590  which passes through the pivot pin hole  569 . 
     A supporting sleeve  501  is typically held in a fixed location by steps, flanges, or other structures in a valve assembly (not shown). The inside diameter of the supporting sleeve  501  is slightly greater than the outside diameter of the rocker elements  540 ,  560  and the reactive element  580 , but smaller than the outside diameter of the passive element  520 . This arrangement causes the supporting sleeve  501  to hold the passive element  520  axially fixed, while the other coupled elements may be fit inside the support sleeve  501  with sufficient clearance to allow the motion of the elements. The outside diameter and length of the supporting sleeve  501  may be chosen according to convenience related to other structures in a valve assembly (not shown). Alternatively, suitable features may be provided in a valve assembly to hold the passive element  520  in a fixed axial location without a supporting sleeve  501 . Mechanical coupling among the elements of the movement increasing mechanism assembly  500  has been previously described regarding links and lock pins. It is to be further understood that mechanical coupling of the active shaft  505  to the rocker elements  540 ,  560  is effected by the active pivot pin  590  simultaneously passing through the pivot pin hole  549  of the left rocker element  540 , though the shaft pin hole  508 , and through the pivot pin hole  569  of the right rocker element  560 . While it is imperative that the left and right rocker elements  540 ,  560  must be free to rotate independently about the active pivot pin  590 , those skilled in the art may choose to make the active pivot pin  590  fit snugly into the shaft pin hole  508  or may choose other methods for retaining the active pivot pin such as clips (not shown). 
     Actuator force applied to the chamfered cavity  509  in the upper end surface of the active shaft  505 , or otherwise communicated to the active pivot pin  590 , is immediately transferred to the rocker elements  540 ,  560  by the pivot pin holes  549 ,  569  located diametrically opposite to one another. The passive element  520  is coupled to the front left upward link  542  by the second lock pin  532  inserted through the link upper hole  546  and the passive element left lock pin hole  521 . Consequently, the passive element  520  being held in an axially fixed location also holds the front left upward link  542  axially fixed, and thereby further holds the first lock pin  533  and the left rocker front lock pin hole  543  axially fixed. Motion imparted to the left rocker pivot pin hole  549  thus makes the left rocker element  540  undergo a slight rotation about the front lock pin hole  543 . The slight rotation of the left rocker element  540  causes the rear portion of the left rocker element  540  to move in the same direction by a greater amount with the left rocker rear lock pin hole  545  and the third lock pin  535  thus forcing the rear left downward link  544  to move as well. The rear left downward link  544  is coupled to the reactive element  580  by the fourth lock pin  534  inserted through the link lower hole  548  and the reactive element left lock pin hole  583 . Consequently, downward motion of the active shaft  505  causes downward motion of the rear left downward link  544  which imparts downward motion to the reactive element  580 . The passive element  520  is also coupled to the rear right upward link  566  by the seventh lock pin  576  inserted through the link upper hole  562  and the passive element right lock pin hole  525 . Consequently, the passive element  520  being held in an axially fixed location also holds the rear right upward link  566  axially fixed and thereby further holds the eighth lock pin  575  and the right rocker rear lock pin hole  565  axially fixed. Motion imparted to the right rocker pivot pin hole  569  thus makes the right rocker element  560  undergo a slight rotation about the rear lock pin hole  565 . The slight rotation of the right rocker element  560  causes the front portion of the right rocker element  560  to move in the same direction by a greater amount with the right rocker front lock pin hole  567  and the fifth lock pin  577 , thus forcing the front right downward link  568  to move as well. The front right downward link  568  is coupled to the reactive element  580  by the sixth lock pin  578  inserted through the link lower hole  564  and the reactive element right lock pin hole  587 . Consequently, downward motion of the active shaft  505  causes downward motion of the front right downward link  568  which imparts downward motion to the reactive element  580 . The foregoing explains how movement of the active shaft  505  is translated into increased movement of the reactive element  580  in the same direction. 
     Undesirable friction in the mechanism is avoided by keeping the active shaft  505  centered inside the corresponding central axial hole  529 , which pierces the upper disk-shaped passive element  520 . A flat disk spring  507  attached to the upper surface of the passive element  520  and extending to contact the end of the upper surface of the passive element  520  is a convenient approach for preventing undesirable friction. The flat disk spring  507  may be attached to the active shaft by welding, adhesive, staking to a ridge (not shown) around the perimeter of the chamfered cavity  509 , or other suitable means. 
     In the disclosed embodiment, the left rocker element  540  and right rocker element  560  are substantially identical and merely rotated by 180 degrees about the movement-increasing mechanism central axis. Additionally, the rocker lock pin holes  543 ,  565  enabling connection to the upward links  542 ,  566  are spaced at a substantially identical distance from the pivot pin holes  549 ,  569 . The other rocker lock pin holes  545 ,  567 , enabling connection to the downward links  544 ,  568 , also are spaced at a substantially identical distance from the pivot pin holes  549 ,  569 , though that distance may be different. The ratio of these respective distances establishes the specific translational multiplication (gain) desired from a particular movement increasing mechanism assembly. Representative dimensions and resulting movement ratios are shown in Table 2 and illustrated particularly in  FIGS. 8A ,  8 B, and  8 C. Retention of the eight lock pins may be accomplished by providing a snug fit in the holes of the link elements, or a snug fit in the lock pin holes in the various full and partial disk-shaped elements, or a suitable combination of these or other choices (e.g. threads, adhesive, staking, etc.) as optimized for particular manufacturing methods. 
     The embodiment discussed so far, in connection with  FIGS. 5A ,  5 B,  5 C,  5 D,  6 ,  7 A, and  7 B, has the same distance between the pivot pin holes  549 ,  569  and the rocker front lock pin holes  543 ,  567  as between the pivot pin holes  549 ,  569  and the rocker rear lock pin holes  545 ,  565 . As may be seen in  FIG. 8A , the lock pin hole placement in the rocker elements is symmetrical for this embodiment. However, a second modified embodiment of the movement increasing mechanism  500  is illustrated in  FIG. 8B , wherein the rocker elements  640 ,  660  have lock pin holes that are not symmetrically located with respect to the corresponding pivot pin holes. The rear left lock pin hole  645  and the front right lock pin hole  667  are the same distance from the corresponding pivot pin holes  649 ,  669  as in the prior embodiment, and thus make the downward link locations suitable for coincident matching with axial slots  584 ,  588  in the same reactive element  580 . The front left lock pin hole  643  and the rear right lock pin hole  665  are located a smaller distance from the corresponding pivot pin holes  649 ,  669  compared to the previous embodiment, and thus make the upward link locations different as well. A different passive element  620  must be used, having axial slots properly placed to intercept the upward links, for the second embodiment of  FIG. 8B . The ratio of the smaller upward link separation compared to the previous distance makes the second example rocker elements  640 ,  660  function as levers that impart more increased motion to the reactive element  580  than the actuator imparts to the active shaft  505 . 
     A third modified embodiment of a direction reversing mechanism  500  constructed in accordance with the principles of the present invention is illustrated in  FIG. 8C , wherein modified rocker elements  740 ,  760  have lock pin holes that are not symmetrically placed with respect to the corresponding pivot holes. The rear left lock pin hole  745  and the front right lock pin hole  767  are a smaller distance from the corresponding pivot pin holes  749 ,  769  compared to the prior embodiments, and thus make the downward link locations different as well. A different reactive element  780  must be used, having axial slots properly placed to intercept the downward links, for this embodiment. The front left lock pin hole  743  and the rear right lock pin hole  765  are located at substantially the same distance from the corresponding pivot pin holes  749 ,  769 , and in the previous embodiment, and thus make the upward link locations suitable for coincident matching with axial slots  524 ,  528  in the same first embodiment active element  520 . The ratio of the smaller downward link separation compared to the previous distance makes the rocker elements  740 ,  760  of this embodiment function as levers that impart less increased motion to the reactive element  780  than the actuator imparts to the active shaft  505 . 
     
       
         
               
               
               
               
               
               
               
               
             
               
               
               
               
               
               
               
               
             
           
               
                 TABLE 2 
               
               
                   
               
               
                 Movement 
                   
                   
                 left rocker ratio 
                   
                   
                 right rocker ratio 
                   
               
               
                 Increasing 
                 left rocker element 
                 left rocker element 
                 of active shaft 
                 right rocker element 
                 right rocker element 
                 of active shaft 
               
               
                 Mechanism 
                 front lock pin hole 
                 rear lock pin hole 
                 movement to 
                 front lock pin hole 
                 rear lock pin hole 
                 movement to 
                 ratio of 
               
               
                 Assembly 
                 (upward link) to 
                 (downward link) to 
                 reactive element 
                 (downward link) to 
                 (upward link) to 
                 reactive element 
                 movement 
               
               
                 Figure 
                 pivot pin hole 
                 pivot pin hole 
                 movement 
                 pivot pin hole 
                 pivot pin hole 
                 movement 
                 increase 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 8A 
                 0.165″ 
                 0.165″ 
                 0.5 
                 0.165″ 
                 0.165″ 
                 0.5 
                 2.0 
               
               
                 8B 
                 0.110″ 
                 0.165″ 
                 0.4 
                 0.165″ 
                 0.110″ 
                 0.4 
                 2.5 
               
               
                 8C 
                 0.165″ 
                 0.110″ 
                 0.6 
                 0.110″ 
                 0.165″ 
                 0.6 
                 1.67 
               
               
                   
               
             
          
         
       
     
     Thus, as can be seen from a review of the foregoing description and accompanying drawings, the inventive system and methods involve an innovative mechanical coupling between an actuator, such as a piezoelectric actuator, and a valve, such as a diaphragm valve. The coupling permits the stroke to be adjusted (expanded, contracted, or reversed), and operates using a scissor-lift concept. 
     While this invention has been described with respect to various specific examples and embodiments, it is to be understood that various modifications may be made without departing from the scope thereof. Therefore, the above description should not be construed as limiting the invention, but merely as an exemplification of preferred embodiments thereof and that the invention can be variously practiced within the scope of the following claims.