Abstract:
A valve assembly includes a valve and a gearbox. The valve includes a valve body having a drive opening and a mounting surface adjacent the drive opening. At least one mounting bore is formed in the mounting surface. At least one rigid pin is fixed to and projects from the mounting surface. A rotatable valve member is disposed in the valve body. A gearbox is operable to rotate the valve member through the drive opening. The gearbox includes a casing including a mounting wall positioned adjacent the mounting surface of the valve body. At least one mounting hole is formed in the mounting wall and is disposed adjacent the mounting bore. At least one pin hole is formed in the mounting wall and receives the pin. A drive hole is formed in the mounting wall and communicates with the drive opening. At least one fastener extends through the mounting hole and engages the mounting bore to secure the casing to the mounting surface. The pin resists relative rotational movement of the casing and the valve body.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to valves and, more particularly, to valves including gearboxes mounted thereon. 
     BACKGROUND OF THE INVENTION 
     Polymeric ball valves are widely used for a variety of industrial applications. Polymeric ball valves typically provide the advantages of relatively light weight, low cost, corrosion resistance, and the ability to be welded on site into a piping system. 
     A known method of forming a polymeric ball valve includes providing a polymeric body/end piece and a polymeric end piece. A valve ball is disposed in the body/end piece and the end piece is fused to the body/end piece to enclose the valve ball in an integral valve body. A pair of resilient, ring-shaped seats provide seals between the ball and the body/end piece and the end piece. Each seat is held in place by a respective ring-shaped seat retainer. An example of a valve of this construction is disclosed in U.S. Pat. No. 5,232,201 to Spears et al. 
     A preferred method for forming a ball valve of the type described includes inserting a first seat, a first seat retainer and the ball into the body/end piece. Thereafter, a second seat retainer, a second seat and the end piece are placed over the ball and the end piece is fused to the body/end piece. 
     During the assembly procedure, the seats should be maintained in the desired position to ensure proper mating between the seats and the ball. One method for holding the seat retainer, and thereby the seat, in place includes providing flanges projecting inwardly from the body/end piece and the end piece, outer threads on the flanges and inner threads on the seat retainers. The seat retainers are screwed onto the flanges and thereby held in place. However, the threads must be molded, machined or otherwise formed on the body/end and end pieces. The thread formation may add significantly to the cost and inconvenience of manufacturing the valve. In particular, because the seat retainers and the body/end and end pieces are typically formed of polyethylene or polypropylene, care must be taken in forming the threads. Furthermore, care must be taken in screwing the seat retainers on to avoid cross-threading and damaging the threads. Additionally, a tendency may exist to distort the seat as the seat retainer rotates into engagement with the seat, or to apply too much or too little pressure to the seat by under-tightening or over-tightening the seat retainer. 
     Polymeric ball valves (and other valves including rotatable valve members) may be provided with a gearbox to facilitate rotation of the ball to open and close the valve. Typically, the gearbox includes a casing, a gear reducer and a drive shaft adapted to engage a valve stem which is connected to the ball. Drive means such as an electric motor may be disposed in or on the casing or otherwise associated with the gearbox. 
     In order to secure the gearbox to a polymeric ball valve, it is known to provide an integral upstanding flange on the valve body. The flange surrounds the valve stem. Holes are formed radially through the flange. The gearbox may be mounted on the flange by inserting bolts through the holes. 
     The foregoing gearbox mounting arrangement may suffer from a number of potential drawbacks. The provision of an upstanding flange which is strong enough and secure enough to resist torque from the gearbox without failure may add significantly to the weight and to the cost of forming the valve. Moreover, it may be necessary to provide a special bracket on the gearbox to allow mounting on the flange. 
     SUMMARY OF THE INVENTION 
     According to embodiments of the present invention, a valve is adapted to receive a gearbox. The valve includes a valve body having a drive opening and a mounting surface adjacent the drive opening. At least one mounting bore is formed in the mounting surface and is adapted to receive a fastener. At least one rigid pin is fixed to and projects from the mounting surface. A rotatable valve member is disposed in the valve body and is operable through the drive opening. 
     According to further embodiments of the present invention, a valve assembly includes a valve and a gearbox. The valve includes a valve body having a drive opening and a mounting surface adjacent the drive opening. At least one mounting bore is formed in the mounting surface. At least one rigid pin is fixed to and projects from the mounting surface. A rotatable valve member is disposed in the valve body. The gearbox is operable to rotate the valve member through the drive opening. The gearbox includes a casing including a mounting wall positioned adjacent the mounting surface of the valve body. At least one mounting hole is formed in the mounting wall and is disposed adjacent the mounting bore. At least one pin hole is formed in the mounting wall and receives the pin. A drive hole is formed in the mounting wall and communicates with the drive opening. At least one fastener extends through the mounting hole and engages the mounting bore to secure the casing to the mounting surface. The pin resists relative rotational movement of the casing and the valve body. 
     According to further embodiments of the present invention, a method for mounting a gearbox on a valve of the type having a valve body and a rotatable valve member disposed in the valve body includes placing the gearbox on a mounting surface of the valve body such that a drive hole formed in a mounting wall of the gearbox communicates with a drive opening in the valve body and such that at least one rigid pin fixed to and projecting from the mounting surface is received in at least one corresponding pin hole in the mounting wall of the gearbox. The method further includes inserting fasteners through at least one mounting hole in the mounting wall such that the fastener engages a bore formed in the valve body to secure the gearbox to the mounting surface. 
     According to embodiments of the present invention, a method for forming a valve includes providing a body piece including an axially extending annular flange having an outer surface and a first element. The first element comprises at least one of a recess defined in the outer surface of the flange and a projection extending from the outer surface of the flange. A valve seat is placed on the flange. An annular seat retainer is provided. The seat retainer has an inner surface and includes a second element comprising at least one of a recess defined in the inner surface of the retainer and a projection extending from the inner surface of the seat retainer. The seat retainer is slid axially onto the flange until the first and second elements snap fit into engagement and such that the seat is thereby retained in position on the flange. 
     Preferably, the first element comprises a continuous, endless, circumferential, radially extending groove, the second element comprises a continuous, endless, circumferential, radially extending rib, and the step of axially sliding the seat retainer onto the flange includes snap fitting the rib into engagement with the groove. 
     According to further embodiments of the present invention, a valve includes a valve body defining a cavity and including a flange having an outer surface and a first element. The first element includes at least one of a recess defined in the outer surface of the flange and a projection extending from the outer surface of the flange. A seat retainer is mounted on the flange and has an inner surface. The seat retainer includes a second element including at least one of a recess defined in the inner surface of the seat retainer and a projection extending from the inner surface of the seat retainer. A valve seat is retained on the flange by the seat retainer. The seat retainer is secured to the flange by a cooperative snap fit engagement between the first and second elements. A valve member may be rotatably mounted in the cavity and engage the valve seat. 
     Preferably, the first element comprises a continuous, endless, circumferential, radially extending groove, and the second element comprises a continuous, endless, circumferential, radially extending rib. The seat retainer is secured to the flange by a cooperative snap fit engagement between the rib and the groove. Preferably, the groove is defined in the outer surface of the flange and the rib extends radially inwardly from the inner surface of the seat retainer. 
     The valve body may include first and second body pieces. The body pieces may be fused together. Preferably, the body pieces and the seat retainer are formed of polymeric material. 
     According to further embodiments of the present invention, a valve assembly includes a valve and a gearbox. The valve includes a valve body having a drive opening and a mounting surface adjacent the drive opening. A rotatable valve member is disposed in the valve body. The gearbox is operable to rotate the valve member through the drive opening. The gearbox includes a casing including a mounting wall positioned adjacent the mounting surface of the valve body. At least one mounting hole is formed in the mounting wall. A drive hole is formed in the mounting wall and communicates with the drive opening. At least one rigid pin is fixed to and projects from one of the mounting surface and the bottom wall and is received in the other of the mounting surface and the bottom wall. At least one fastener extends through the mounting hole to secure the casing to the mounting surface. The pill resists relative rotational movement of the casing and the valve body. 
     Objects of the present invention will be appreciated by those of ordinary skill in the art from a reading of the Figures and the detailed description of the preferred embodiments which follow, such description being merely illustrative of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a center cross-sectional view of a valve assembly according to the present invention; 
     FIG. 2 is a center cross-sectional, fragmentary, enlarged view of a second body piece, a seat retainer and a seat of the valve assembly of FIG. 1; 
     FIG. 3 is a front, perspective view of the second body piece of the valve assembly of FIG. 1; 
     FIG. 4 is a front elevational view of the second body piece of the valve assembly of FIG. 1; 
     FIG. 5 is a center cross-sectional view of the second body piece of the valve assembly of FIG. 1 taken along the line  5 — 5  of FIG. 4; 
     FIG. 6 is a center cross-sectional, fragmentary, enlarged view of the second body piece of the valve assembly of FIG. 1; 
     FIG. 7 is a center cross-sectional view of a first body piece of the valve assembly of FIG. 1; 
     FIG. 8 is a front, perspective view of the seat retainer of the valve assembly of FIG. 1; 
     FIG. 9 is a front elevational view of the seat retainer of the valve assembly of FIG. 1; 
     FIG. 10 is a cross-sectional view of the seat retainer of the valve assembly of FIG. 1 taken along the line  10 — 10  of FIG. 9; 
     FIG. 11 is a front, perspective view of the seat forming a part of the valve assembly of FIG. 1; 
     FIG. 12 is a cross-sectional view of the seat of the valve assembly of FIG. 1 taken along the line  12 — 12  of FIG. 11; 
     FIG. 13 is an exploded, perspective view of the valve assembly of FIG. 1 showing a gearbox casing and means for mounting the same to the valve assembly; 
     FIG. 14 is a perspective view of the valve assembly of FIG. 1 with the gearbox mounted thereon; 
     FIG. 15 is a top, schematic view of the valve assembly of FIG. 1 indicating the relative locations of holes, bores and pins forming a part of the valve assembly; 
     FIG. 16 is a cross-sectional, fragmentary, enlarged view of the valve assembly of FIG. 1 taken along the line  16 — 16  of FIG. 15; and 
     FIG. 17 is a cross-sectional, fragmentary, enlarged view of the valve assembly of FIG. 1 taken along the line  17 — 17  of FIG.  15 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. 
     With reference to the drawings, a valve assembly according to a preferred embodiment of the present invention is shown therein and generally designated  100 . The valve assembly  100  is preferably and illustratively a polymeric ball valve. With reference to FIG. 1, the valve assembly  100  defines a lengthwise axis A—A. As used herein, “radially ” refers to those directions perpendicular to and outward from the axis A—A. The valve assembly  100  includes a first body piece  130  (also shown in FIG. 7) and a second body piece  140  (also shown in FIGS. 2-6) joined to the first body piece along respective faces  130 A,  140 A. The body pieces  130 ,  140  form opposed end body portions of the valve assembly  100 . The body piece  130  also includes a center body portion  139  extending axially toward the second body piece  140 . 
     The center body portion  139  defines a cavity C. A valve ball  120  is disposed in the cavity C. A valve stem  110  extends through a hole  137  in the body piece  130  and includes a tab  112  keyed into a slot in the ball  120  such that the ball  120  may be rotated by turning the stem  110 . A first passageway P 1  is defined in the second body piece  140 , a second passageway P 2  is defined in the ball  120  a third passageway P 3  is defined in the first body piece  130 . 
     As will be recognized by those of ordinary skill in the art, the valve assembly  100  may be opened by rotating the ball  120  about the axis B—B of the stem  110  such that the passageways P 1 , P 2  and P 3  are aligned, and closed by rotating the ball  110  such that the passageway P 2  is perpendicular to the passageways P 1  and P 3  and the flow of media through the valve assembly  100  is blocked by the ball  120 . Elastomeric, annular valve seats  160  are positioned between the first and second body pieces  130 ,  140  and the ball  120 . The seats  160  provide a seal between the body pieces  130 ,  140  and the ball  120  when the valve assembly  100  is closed to prevent or inhibit media from flowing through the passage P 1  or the passage P 3  and around the ball  120 . As discussed in more detail below, the seats  160  are retained and supported by respective associated seat retainers  150  (see FIGS. 8-10) and flanges  131 ,  141  of the first and second body pieces  130 ,  140 . 
     Turning to the second body piece  140  in more detail and with reference to FIGS. 1-6, the body piece  140  includes an axially projecting annular flange  141  and a surrounding axially extending groove  144 . An endless, annular end groove  146  is defined in the inward end of the flange  141 . The end groove  146  has adjoining walls  146 A,  146 B. An endless, annular, continuous, radially inwardly extending groove  142  is formed in the outer peripheral surface of the flange  141 . The groove  142  has a radially extending wall  142 B, an axially extending wall  142 A and an angled wall  142 C. Preferably, the groove  142  is formed such that the axis A—A extends through the center of the circle defined by the groove  142  and such that the axis A—A is orthogonal to a plane defined by the wall  142 B of the groove. 
     The body piece  140  is preferably integrally formed from a suitable polymeric material, more preferably a thermoplastic material. More preferably, the body piece  140  is formed of high density polyethylene, low density polyethylene, or PVC. Most preferably, the body piece  140  is formed of high density polyethylene. The body piece is preferably machined from billet or bar stock, but may be molded. The grooves  142 ,  144  and  146  are preferably molded into the body piece  140 . However, one or more of the grooves  142 ,  144 ,  146  may be machined into the body piece  140 . 
     As best seen in FIGS. 8-10, the seat retainer  150  is a circular ring having an annular head  158  and an annular base  154  extending axially from the head. The head  158  has an angled front wall  158 A, an angled rear wall  157  and an annular projection or rib  156  extending inwardly. A continuous, annular projection or rib  152  extends radially inwardly from the inner surface of the base  152 . The projection  152  is preferably endless as shown. The projection  152  includes a radially extending wall  152 C, an axially extending wall  152 A and an angled wall  152 B. The seat retainer  150  is preferably formed from a resilient material. More preferably, the seat retainer is formed of a material having a modulus of elasticity of between about 29×10 −6  psi and 9.0×10 −4  psi. Preferably, the seat retainer  150  is formed of stainless steel, polyethylene, or polypropylene. Most preferably, the seat retainer  150  is formed of polypropylene. The seat retainer  150  may be formed by molding or fabrication. The inner diameter V (see FIG. 9) of the base  154  of the seat retainer  150  (not including the projection  152 ; see FIG. 9) is preferably substantially the same or slightly greater than the outer diameter U (see FIG. 5) of the flange  141 . 
     As best seen in FIGS. 11 and 12, the seat  160  forms a circular ring. The seat  160  has an inner, forward lobe or portion  163 , an outer, forward portion  167  and a rearward portion  166 . Preferably, the seat  160  is formed of rubber. Preferably, the durometer of the seat  160  is between about  50  and  90 . The seat  160  may be formed by molding. 
     FIG. 2 illustrates the relative arrangement of the second body piece  140 , the seat  160  and the seat retainer  150  for retaining the seat  160  on the body piece  140 . The base  154  surrounds the flange  141  and the projection  156  extends radially inwardly. The seat  160  is captured between the flange  141  and the projection  156  such that the portion  166  (see FIG. 12) is disposed in the groove  146 , the projection  156  is received between the portions  163  and  167 , and the portion  163  is exposed. 
     The projection  152  is received in the groove  142 . The groove  142  and the projection  152  have complementary shapes and sizes so that the projection  152  is fully received in the groove  142 . The reversed barb shapes of the projection  152  and the groove  142  cause the projection  152  and the groove  142  to resist removal of the seat retainer  150  by way of the seat retainer  150  sliding axially off of the flange  141 . 
     From the foregoing description, it will be appreciated that the seat  160  is retained on the flange  141  and the seat retainer  150  such that the seat portion  163  is exposed and positioned to operatively engage the periphery of the ball  120 . As will be better appreciated from the description below of the method for assembling the valve assembly  100 , the seat retaining arrangement allows for improved convenience and consistency in the manufacture of the valve assembly. 
     The groove  142  is located a prescribed distance N (FIG. 6) from the front edge of the flange  141 , preferably between about 0.12 and 2.0 inches. The prescribed spacing ensures a prescribed axial distance between the head  158  and the flange  141 , and thereby a prescribed and desired pressure on the seat  160 . 
     The radial depth F (FIG. 6) of the groove  142  is preferably between about 0.060 and 0.380 inch greater than the radial height J (FIG. 10) of the projection  152 . The height J of the projection  152  is preferably between about 0.030 and 0.370 inch. The axial length K (FIG. 10) of the wall  152 C is preferably between about 0.12 and 0.50 inch. The angle L (FIG. 10) of the wall  152 B with respect to radial is preferably between about 10 and 80 degrees. The angle E (FIG. 6) of the wall  142 C with respect to radial is preferably the same as the angle L. The axial depth I of the groove  146  and the angle H between the walls  146 A and  146 B are preferably complementary to the shape of the portion  167  of the seat  160 . The projection  156  preferably has a length Q (FIG. 10) of between about 0.030 and 0.300 inch. The angle M of the wall  158 A with respect to radial should be sized to provide clearance with the ball  120  in the assembled valve assembly  100 . 
     The first body piece  130  is preferably formed in the same manner and from the same materials as discussed above for the second body piece  140 . The arrangement for retaining the seat  160  on the first body piece  130  is essentially a mirror image of the arrangement for retaining the seat  160  on the second body piece  140  about a plane passing through the valve stem axis B—B and normal to the axis A—A. With reference to FIG. 7, the body piece  130  includes a flange  131 , a groove  132 , a groove  134  and an end groove  136  corresponding to the flange  141 , the groove  142 , the groove  144  and the groove  146 , respectively, of the second body piece  140 . The seat retainer  150  and the seat  160  mounted on the body piece  130  are preferably duplicates of the seat retainer  150  and the seat  160  mounted on the body piece  140 . While the body piece  130  is not shown in perspective view, it will be readily appreciated that the shape of the body piece  130  is substantially the same as that of the body piece  140  (see, e.g., FIG. 3) with the further provision of the annular wall  139  extending forwardly. 
     According to a preferred method of the present invention, the valve assembly  100  may be assembled in the following manner. The seat  160  is mounted in the groove  136 . The first resilient seat retainer  150  is then slid axially over the flange  131  until the projection  152  is received and snaps into the groove  132 , thereby latching the seat retainer  150  onto the flange  141 . In this manner, the projection  156  of the seat retainer  150  engages the seat  150  between the portions  163  and  167 . The seat  160  is now securely retained on the flange  131  so that the body piece  130  may be handled and reoriented as desired. The continuous and radially oriented groove  132  ensures that the seat retainer  150  is positively located and uniform pressure is applied along the full perimeter of the seat  160 , ultimately allowing a uniform seal with the ball  120 . 
     The ball  120  is then inserted into the cavity C such that it engages the seat  160 . The stem  110  or portions thereof also may be inserted into the cavity C, suitable methods for mounting the stem being known to those of ordinary skill in the art. 
     Prior to, concurrently with or following the insertion of the ball  120  into the cavity C, the seat  160  and the seat retainer  150  are mounted on the second body piece  140  in the same manner as described for mounting the seat  160  and the seat retainer  150  on the first body piece  130 . Again, it will be appreciated that, because the seat  160  is now securely retained on the flange  141 , the subassembly may be handled and reoriented as desired. 
     The subassembly including the body piece  140 , the seat retainer  150  and the seat  160  is then mounted on the body piece  130  so as to encapsulate the ball  120  in the cavity C. Any suitable method for joining the body piece  140  to the body piece  130  may be employed. Preferably, the body piece  140  is secured to the body piece  130  by heating and fusing the faces  130 A and  140 A. Suitable equipment for fusing the body pieces includes a high velocity fusion machine such as the Model No. 824 available from McElroy Manufacturing, Inc of Tulsa, Okla. Alternatively, the body pieces  130 ,  140  may be joined by fastening, gluing or spin welding, for example. 
     The seat retaining arrangement secures, at least temporarily, the seats  160  on the body piece  130  and the body piece  140  so that the body pieces may be oriented as desired to facilitate other assembly steps. In particular, the seat retaining arrangement allows the body pieces to each be oriented and moved as needed to facilitate the body joining procedure (e.g., the fusing step). This convenience is provided without requiring relatively complex, unreliable, costly and/or precise machining or forming operations or special handling considerations. Moreover, the grooves  132 ,  142  and the projections  152  securely retain the seat even when the body pieces  130 ,  140 , seat retainers  150  and/or seats  160  expand and contract due to changes in temperature. 
     While the arrangement described above is preferred, it is also contemplated that the locations of the projections  152  and the grooves  132 ,  142  may be reversed (not shown). Make particularly, the annular projections may be integrally formed or attached to the outer surfaces of the flanges  131 ,  141  and the complementary grooves may be formed in the inner surfaces of the seat retainers  150 . 
     Similarly, while the grooves  132 ,  142  and projections  152  are preferably continuous and endless as described above, it is also contemplated that each projection  152  may be replaced with a plurality of spaced apart projections with circumferential gaps between adjacent projections. The projections would otherwise be formed as described above. If this configuration of projections is employed, the corresponding groove  132 ,  142  may be replaced with a plurality of spaced apart recesses with circumferential gaps between adjacent recesses. The recesses would otherwise be formed as described above. 
     The valve assembly  100  is also provided with an improved gearbox mounting arrangement. With reference to FIGS.  1  and  13 - 17 , a gearbox  180  (see FIG. 1) is mounted on a mounting surface  135  of the body portion  139 . The gearbox  180  may be any suitable gearbox. Suitable gearboxes include Model No. SQ-6 available from Dynatorque of Muskegon, Mich.. Conventionally, the gearbox  180  includes a motor  188 , manual actuator or the like which selectively drives the stem  110  via a gear reducer  188 A that engages an upper portion  114  of the stem  110 . The gearbox  180  has a casing  182  including a bottom wall  182 A. Such gearboxes are well known to those of ordinary skill in the art and, therefore, will not be described in farther detail herein. 
     As shown in FIG. 14, the casing  182  (and, thereby, the gearbox  180 ) is positively secured to the body piece  130  by four threaded bolts  190 . Additionally, a pair of rigid, upstanding pins  196  brace the gearbox  180  against reactive torque as drive force is applied to the stem  110 . 
     With reference to FIG. 13, the bolts  190  are received through holes  184  in the bottom wall  182 A and threadedly engage respective threaded bores  192 . Preferably, and as shown, the holes  184  are countersunk to positively locate the bottom wall  182  with respect to the bolts  190 , and thereby with respect to the mounting surface  135 . A hole  187  is also formed in the bottom wall  182 A and is positioned to overlie the hole  137  when the casing  182  is mounted on the body piece  130 . The stem  110  (not shown in FIGS. 13 and 14) extends up through the holes  137 ,  187  and engages the gear reducer. 
     Preferably, each bore  192  includes an internally threaded nut  192 A as shown in FIG.  16 . Each nut  192 A is formed of a material that is harder than the material of the body piece  130 . Each nut  192 A is bonded and/or adhered within a bore formed in the body piece  130  as shown. Preferably, each nut  192 A is formed of metal. The nuts  192 A provide a more secure engagement with the bolts  190 . The nuts  192 A also facilitate manufacture because threads need not be formed in the body piece  130 . More or fewer bores  192  and bolts  190  may be provided; however, preferably at least four bores  192  and four bolts  190  are used. 
     The pins  196  are preferably formed of metal and, more preferably, of stainless steel. The pins  196  are embedded in the body piece  130  as shown in FIG.  17 . The polymeric material of the body piece  130  is bonded and/or adhered to the pins  196 . If bonded, the pins  196  are preferably bonded in place during the molding of the valve body piece  130 . If adhered, preferably a structural acrylic adhesive is used. The pins  196  are received in respective holes  186  formed in the bottom wall  182 A. More or fewer pins  196  may be provided; however, preferably at least two pins  196  are used. 
     Preferably, the pins  196  each have a length P extending above the mounting surface  135  (see FIG. 17) of at least 0.12 inch, and more preferably of between about 0.12 inch and 0.75 inch. Preferably, the pins  196  each have a length Y embedded in the body piece  130  which is between about one and one and a half times the diameter of the pin  196 . The centers of the pins  196  are equidistant from the axis of stem rotation and are on diametrically opposite sides thereof. Preferably, the pins  196  are each spaced between about 1 and 6 inches from the center of the hole  137 , depending on the anticipated torque loads. 
     When the gearbox  180  is mounted on the mounting surface  135 , the bolts serve to positively position and secure the gearbox  180  on the body piece  130 . In this way, the mounting arrangement ensures that the gearbox  180  is properly aligned with the stem  110  and other components of the valve assembly  100 . The pins  196  serve to resist reactive forces from the motor as the gearbox attempts to turn the ball  120 . In this manner, stresses on the bolts  190  and the nuts  192 A are reduced or eliminated. 
     Alternatively, the pins  196  may be affixed to the bottom wall  182 A of the casing  182  and received in mating bores in the mounting surface  135 . Preferably, in this configuration, the pins are press fitted into the mating bores in the body to provide a tight fit and to accommodate relaxation of the polymeric body material. However, this alternative configuration may not be as convenient to assemble and may not provide as tight a fit as the gearbox mounting arrangement described above. 
     Also alternatively, the threaded bores  192  may be replaced with externally threaded, upstanding studs partially embedded in the valve body. The studs extend up through the holes  184  and the gearbox is secured in place by internally threaded nuts. However, due to the tendency of the polymeric valve body material (especially polyethylene) to relax under load, this alternative gearbox mounting arrangement may not provide as rigid and durable of a mount as the gearbox mounting arrangement first described above. 
     It will be appreciated that the valve assembly may include other gearbox mounting arrangements or may not use a gearbox. It will also be appreciated that the gearbox arrangement described herein may be used with valve assemblies of other designs. 
     The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the appended claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.