Abstract:
A power valve wrench includes a power drive assembly having a motor and a speed reduction device driving an annulus which defines a large center opening and a plurality of lugs or recesses on the interior wall of the annulus. The opening in the annulus receives a drive member having complementary lugs or recesses. The drive member, in turn defines a concentric polygonal opening which may be square, hexagonal, octagonal or other regular polygon shape which receives a complementarily configured stanchion of a valve handwheel drive member. A selection of valve handwheel drive members having 4, 6, 8, 10 or 12 slots may be utilized with the power valve wrench. A safety or retaining ring removably attached to the valve handwheel drive member retains the member on a valve handwheel.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates generally to wrenches for opening and closing valves operable by hand wheels and more particularly to a power valve wrench having a motor which drives a hand wheel engaging member through a speed reduction device. 
     In refineries, petrochemical plants, steam or nuclear power generating plants, water treatment plants and other facilities where large liquid and gas flows are common, significant numbers of large valves are equally common. Typically, such valves are operated by hand wheels having diameters of from several inches to a few feet. Although hand wheel size is related generally to the size of the valve and the torque necessary to open and close it, the actual torque necessary to open and close a valve, either as it ages or is only occasionally operated, can increase dramatically from the initial operating torque. In many instances, the operating torque of an aging or seldom used valve may be great enough to present the potential for human injury or it may simply render it inoperable. 
     This problem has been addressed in the prior art. For example, U.S. Pat. No. 1,460,922 discloses a valve actuating means compromising a radially extending handle which is disposed about the valve stem and includes projections which engage the valve hand wheel or its spokes. 
     A similar construction is illustrated in U.S. Pat. No. 2,920,517 wherein an elongate handle is received on the stem of the valve and a pair of spaced apart projections straddle a valve spoke and engage the hand wheel. 
     U.S. Pat. Nos. 2,086,722 and 2,539,262 disclose valve turning tools which both engage only the outer wheel portion of the hand wheel at two spaced apart locations. 
     U.S. Pat. Nos. 2,682,189 and 4,715,252 both disclose wrench like valve tools which engage the handwheel at one location. While these tools as well as several of the foregoing facilitate the application of increased torque to the valve handwheel, they have in common a significant disadvantage. Because they apply unbalanced force to the handwheel at a single location, a static bending moment is created. Such unbalanced force application is less efficient than balanced, i.e., on center, torque application and can also damage the valve. 
     Study of the foregoing patented devices reveals another difficulty. Many of these devices may slip upon the valve handwheel when torque is applied. Clearly an abrupt, spontaneous repositioning of the device on the handwheel is undesirable. Furthermore, many of these designs are not self retaining and will disconnect and fall from the valve handwheel if not held in position by an operator. Finally, many of the foregoing devices are suitable for only a specific size or limited range of sizes of valve handwheels. 
     My prior U.S. Pat. No. 5,203,240 addresses many of these problems. Here, a circular drive member having a plurality of T-shaped slots engages the spokes of a valve handwheel and is rotated by a ratchet drive mechanism having a handle. While this device addresses many of the problems of the prior art, the opening and closing of a large valve which may require several turns and significant torque application through a ratchet mechanism can be tedious and time consuming. 
     The foregoing suggests that improvements to devices for applying torque to valve handwheels are both desirable and possible. 
     SUMMARY OF THE INVENTION 
     A power valve wrench includes a power drive assembly having a motor and a speed reduction device driving an annulus which defines a large center opening and a plurality of lugs or recesses on the interior wall of the annulus. The opening in the annulus receives a drive member having complementary lugs or recesses. The drive member, in turn defines a concentric polygonal opening which may be square, hexagonal, octagonal or other regular polygon shape which receives a complementarily configured stanchion of a valve handwheel drive member. A selection of valve handwheel drive members having 4, 6, 8, 10 or 12 slots may be utilized with the power valve wrench. A safety or retaining ring removably attached to the valve handwheel drive member retains the member on a valve handwheel. 
     Accordingly, it is an object of the present invention to provide a power apparatus for applying torque to valve handwheels. 
     It is a further object of the present invention to provide a power apparatus for applying torque to handwheels which quickly opens or closes a valve. 
     It is a still further object of the present invention to provide a power apparatus for providing torque to valve handwheels having a plurality of castellated drive members with various arrangements of T-shaped slots. 
     It is a still further object of the present invention to provide a power apparatus for bi-directionally applying torque to valve handwheels. 
     It is a still further object of the present invention to provide a power apparatus for bi-directionally applying torque to valve hand wheels having a safety ring for retaining the apparatus on a valve hand wheel. 
     Further objects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like referenced numbers refer to the same component, element or feature. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is perspective view of a power valve wrench assembly according to the present invention disposed on a handheel of a valve; 
     FIG. 2 is a fragmentary, perspective view with portions broken away of a gear drive mechanism of a power valve wrench assembly according to the present invention; 
     FIG. 3 is an exploded, perspective view from below of a portion of a power valve wrench assembly according to the present invention; and 
     FIG. 4 is a perspective view of a castellated valve drive member having  6  slots for use with a handwheel having  2 ,  3  or  6  spokes. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIG. 1, a power valve wrench assembly according to the present invention is illustrated and generally designated by the reference number  10 . The power valve wrench assembly  10  includes a generally elongate frame  12  having a handle  14 . Both the frame  12  and the handle  14  may include hand grips  16  which may be engaged by the hands of an operator to steady the power valve wrench assembly  10  during use. The hand grip  16  in the handle  14  protects a single or multiple switches (not illustrated) which control the activation and direction of activation of the power valve wrench assembly  10 . An electrical power cord  18  having a suitable plug (not illustrated) is connected to a source of electrical energy when the power valve wrench assembly  10  is in use. 
     Use of the power valve wrench assembly  10  is typically with a large, manually operable fluid control valve  20 . The fluid control valve  20  is disposed in a pipe  22  and includes a rotatable handwheel  24  having a plurality of radially extending spokes  26 . There may be three, four, six, eight or ten spokes  26  and, as noted, they may be radially oriented, obliquely 
     Referring now to FIGS. 1,  2  and  3 , the power valve wrench assembly  10  also includes a bi-directional electric drive motor  30  having an output shaft  32  which bi-directionally drives a worm gear  34 . The worm gear  34  is received within a rectangular housing  36  secured to or integrally formed with a portion of the elongate frame  12  adjacent the electric drive motor  30 . 
     The frame  12  defines a large circular opening  40  which receives a circular drive hub or collar  42  having teeth  44  disposed about its periphery which engage and are driven by the worm gear  34 . Rotation of the output shaft  32  of the electric motor  30  and the worm gear  34  thus rotate the circular drive collar  42  about its axis at a rotational speed greatly reduced from the speed of the electric drive motor  30 . 
     The circular drive collar  42 , in turn, defines a circular opening  48  and includes a plurality, preferably at least four, equally circumferentially spaced-apart notches or recesses  50 . The notches or recesses  50  all open in one direction and receive complementarily configured radial lugs or projections  52  formed on the periphery of an intermediate drive collar  54 . 
     It will be appreciated that the notches or recesses  50  may be interchanged with the lugs or projections  52  such that the notches or recesses  50  are disposed on the intermediate drive collar  54  and the lugs or projection  52  are disposed on the circular drive collar  42 . Alternatively, analogous or similarly functioning coupling structures such as radially extending pins, male and female splines or gear teeth or bayonet type latches, for example, may be utilized to couple the intermediate drive collar  54  to the circular drive collar  42 . 
     The drive collar  54  is cylindrical and defines an outside diameter just slightly less than the inside diameter of the circular opening  48 . One end of the intermediate drive collar  54  is open and the other end is partially closed by an integrally formed end plate  56  which defines a polygonal opening  58 . Preferably, the polygonal opening  58  is hexagonal although other regular polygonal shapes such as eight-sided, ten-sided and twelve-sided may be readily utilized. If, in fact, it is desired to limit use of this device to specific, not readily available components or to limit its use to only authorized personnel, five-sided or seven-sided, for example, polygonal openings or openings having other numbers of sides or irregular shapes may also be utilized. 
     The intermediate drive collar  54  is positioned within the circular opening  48  of the circular drive collar  42  such that the plurality of lugs or projections  52  align with and are received within the plurality of recesses  50 . So disposed, the circular drive collar  42  transmits bi-directional rotational energy to the intermediate drive collar  54  and rotates it upon rotation of the output shaft  32  of the electric drive motor  30  as will be readily appreciated. 
     The intermediate drive collar  54  is retained within the circular opening  48  of the drive collar  40  by a flat retaining annular plate or ring  62 . A plurality of threaded fasteners  64  are utilized to secure the retaining ring  62 . The plurality of threaded fasteners  64  extend through openings  66  in the retaining ring  62  and into a like plurality of threaded blind openings  68  in the intermediate drive collar  54 . The retaining ring  62  thus retains the intermediate drive collar  54  within the center opening  48  of the circular drive collar  42  in a first axial direction. Interengagement of the lugs or projections  52  with the recesses  50  inhibits axial motion of the intermediate drive collar  54  through the center opening  48  of the circular drive collar  42  in the other axial direction. Thus it will be appreciated that the intermediate drive collar  54  is retained within the center opening  48  of the circular drive collar  42  and generally within the frame  12  of the power valve wrench assembly  10 . 
     Referring now to FIGS. 3 and 4, the power valve wrench assembly  10  also includes an annular valve drive socket assembly  70 . The socket assembly  70  includes a central disk or end portion  72 , a cylindrical sidewall portion  74  extending in one direction from the disk or end portion  72  and a drive stanchion  76  extending in the opposite direction from the disk or end portion  72 . At a plurality of preferably equally circumferentially spaced locations in the cylindrical sidewall  74  are disposed T-shaped slots  78 . The T-shaped slots  78  define a narrow, spoke receiving throat region  80  and a wider spoke retaining rectangular region  82 . The axial depth of the rectangular region  82  is preferably at least equal to or slightly greater than the diameter of a typical valve spoke  26 . Preferably, the rectangular region  82  is circumferentially centered on the throat region  80 , that is, adjacent ledges  84  are of equal circumferential length. The ledges  84  in each slot  78  are defined by a pair of opposed teeth  86  which assist retention of the spokes  26  of the handwheel  24  within the slots  78  of the valve drive socket assembly  70 . The valve drive socket assembly  70  illustrated in FIGS. 3 and 4 includes four T-shaped slots  78  equally spaced at  90  degree intervals about the cylindrical sidewall  74 . Such a socket assembly  70  will function with a valve handwheel  24  having either two or four spokes  26 . 
     The socket assembly  70  also includes a drive stub or stanchion  76  having a plurality of axially extending, preferably identical, chordal flats  88 . The flats  88  are preferably six in number and disposed in opposed parallel pairs to form a hexagonal outer surface on the drive stanchion  76 . However, more or fewer flats  88  may be utilized to complement, as noted above, various configurations of the polygonal opening  58  as well as other axially separable couplings such as splines or radially oriented, spring biased detents or locking pins. The drive stanchion  76  terminates in a narrow annulus  92  having a circumferential groove  94  formed in its peripheral surface. The circumferential groove  94  receives a snap ring or C-washer  96  or similar structure which selectively retains the socket assembly  70  in the intermediate drive collar  54  as illustrated in FIGS. 1 and 3. The drive stanchion  76  is hollow and defines a through, preferably circular aperture  98  which may receive the valve stem  28  as illustrated in FIG.  1 . 
     It will be appreciated that the location of the drive stub or stanchion  76  may be exchanged with that of the polygonal opening  58  such that a similarly configured drive stub or stanchion is integrally formed with and extends (downwardly) from the intermediate drive collar  54  and a polygonal opening is disposed in the socket assembly  70 . 
     It is anticipated that in order to make the power valve wrench assembly  10  fully adaptable to all valves  20  and specifically various patterns of spokes  26 , a small number, typically two, three or four valve drive socket assemblies  70  will be available for interchangeable use with a single power valve wrench assembly  10 . For example, in FIG. 4, an alternate embodiment annular valve drive socket assembly  70 ′ is illustrated which includes six T-shaped slots  78 . The six T-shaped slots  78  are in all respects identical to the T-shaped slots  78  illustrated in FIGS. 1 and 3. The six T-shaped slots  78  are arranged at equal  60  degree intervals about the cylindrical sidewall  74  of the socket assembly  70 ′. It will be appreciated that the valve drive socket assembly  70 ′ is adapted for use with a handwheel  24  having either two, three or six equally spaced spokes  26 . It should thus be understood that various and additional socket assemblies  70  defining, for example, five or ten T-shaped slots  78  or any other convenient or necessary number of T-shaped slots  78  required to engage particular handwheel/spoke configurations is wholly within the purview of the present invention. 
     Referring now to FIGS. 1,  3  and  4 , the power valve wrench assembly  10  and specifically the valve drive socket assemblies  70  and  70 ′ preferably include a safety or retaining ring assembly  100 . The retaining ring assembly- 100  includes a metal ring  102  which extends through an arc of approximately 300° and, in any event, at least about 270° and preferably leaves a gap  104  between its ends sufficiently large that it can be positioned about the central portion of a valve  20  and hand wheel  24  from the underside of the hand wheel  24 , that is, the side adjacent the body of the valve  20 . The ring  102  includes a plurality, preferably at least four, radial through apertures  106  which align with a like plurality of radial through apertures  108  formed in the side wall  74  or  74 ′ of the socket assembly  70  or  70 ′ respectively. When positioned as illustrated in FIG. 1 with the apertures  106  in the ring  102  and apertures  108  in the side wall  74  or  74 ′ of the socket  70  or  70 ′, a plurality of register or retaining pins  110  may be inserted therethrough. Each of the register pins  110  includes a radial passageway  112  on its end opposite an enlarged head portion  114 . Each of the through radial apertures  112  receives a respective removable and reusable cotter pin  116  which retains the register or retaining pin  110  in the passageways  106  and  108  and thereby retains the retaining ring  102  on the drive socket  70  or  70 ′ and, in turn, retains the valve hand wheel  24  and specifically the spokes  26  within the T-shaped slots  78 . 
     The retaining ring assembly  100  is positioned as illustrated in FIGS. 1 and 4 after the socket assembly  70  or  70 ′ is installed upon a valve handwheel  24  and facilitates retention of the valve handwheel  24  within the T-shaped slots  78  of the socket assembly  70   70 ′ and reduces the likelihood of unanticipated disconnection of the valve drive socket assembly  70  or  70 ′ from the valve handwheel  24 . 
     To utilize the power valve wrench assembly  10  of the present invention, a specific socket assembly such as the socket assembly  70  or  70 ′ is selected which includes a pattern and number of T-shaped slots  78  which match that pattern and number of the spokes  26  of a particular valve handwheel  24  to be rotated. The selected valve drive socket assembly  70  or  70 ′ and specifically the drive stub or stanchion  76  is then aligned with and inserted into the polygonal opening  58  of the intermediate drive collar  54 . The snap ring  96  is then installed in the circumferential groove  94  to retain the valve drive socket assembly  70  or  70 ′ in the intermediate drive collar  54  as illustrated in FIG.  2 . The valve drive socket assembly  70  or  70 ′ is then positioned on a valve handwheel  24  as illustrated in FIG.  1 . Finally, the retaining ring assembly  100  is positioned as illustrated in FIGS. 1 and 4 and secured to the valve drive socket assembly  70  or  70 ′. 
     So disposed upon the valve handwheel  24 , the switches in the hand grip  16  in the handle  14  are activated to rotate the handwheel  24  in the desired direction and open or close the fluid control valve  20 . As noted in FIG. 1, the circular aperture  98  which extends through the drive stanchion  76  of both the valve drive socket assemblies  70  and  70 ′ permits the valve stem  28  of the fluid control valve  20  to readily extend from the fluid control valve  20 . 
     The foregoing disclosure is the best mode devised by the inventor for practicing this invention. It is apparent, however, that apparatus incorporating modifications and variations will be obvious to one skilled in the art of power wrenches. Inasmuch as the foregoing disclosure presents the best mode contemplated by the inventor for carrying out the invention and is intended to enable any person skilled in the pertinent art to practice this invention, it should not be construed to be limited thereby but should be construed to include such aforementioned obvious variations and be limited only by the spirit and scope of the following claims.