Worm gear torque apparatus

A torque applying tool (10) having a housing or body (14) including a rectangular body portion (16) having a worm receiving opening (20) extending therethrough and an arcuate housing portion (18) having a gear receiving opening (22) extending therethrough at right angles to the worm receiving opening (20). A toothed gear (26) is mounted within gear receiving opening (22) and has a central opening (32) of a hexagonal shape to receive nut (N) therein to be rotated. Worm gear (38) is received within worm receiving opening (20) and has a helical thread (39) thereon formed of a concave shape to engage teeth (28) on gear (26) for rotation of gear (26) and nut (N).

FIELD OF THE INVENTION
 The present invention relates to a worm gear torque apparatus, and more
 particularly to such a worm gear torque device to rotate a nut for
 applying a torque force.
 BACKGROUND OF THE INVENTION
 Flanges, joints, and various pressure lines and pressure vessels are widely
 used in the industry. Opposed flanges on separate members are formed with
 aligned openings and the two members are joined to one another in a
 pressure type manner by first providing a gasket between the two flanges
 and then by connecting the flanges together with threaded stud-like
 members, such as studs, bolts, or stud-bolts, which extend through the
 aligned openings and have a nut engaged thereon. The amount of torque
 applied to the nuts normally determines the tensioning of the studs. It is
 important, particularly in large diameter members, that the tension in the
 studs be sufficient to withstand imposed forces and be uniform as to avoid
 deformation of the flanges and the members to which they are fixed. The
 term "stud" as used herein refers to stud-like members to which the
 invention applies.
 Various devices have been provided heretofore for tensioning studs and have
 been hydraulically actuated as well as non-hydraulically actuated. The
 nuts are normally rotated by a driving member fitting over the nuts for
 rotating the nuts in a manner sufficient to obtain the desired tensioning
 of the stud on which the nut is positioned.
 Prior art stud tensioning devices have utilized a gear fitting over a nut
 in driving relation with the gear rotated by a power mechanism engaging
 the gear for rotating the gear and the nut. The nut is threaded onto a
 stud for tensioning the stud. A power device, such as a fluid motor or
 reciprocating cylinder, has been removably connected to the drive
 mechanism for effecting rotation of the gear and the associated nut.
 In subsea operations the flange members are connected to each other in
 subsea completion systems, such as completion systems for subsea gas
 wells, and it is desirable that stud tensioning devices be operated from
 remotely operated vehicles (ROV), particularly at increased water depths.
 Many of the subsea oil and gas wells are positioned at water depths over
 2,000 feet which is generally undesirable for divers. The torque applying
 device must be capable of fitting over a nut and powered from a suitable
 fluid motor for rotation to obtain the desired tensioning of the stud.
 In some subsea uses, the torque device is utilized for applying a torque to
 a shaft for rotating or driving a separate member. For example, an adapter
 having a male hexagonal end may be inserted within the gear opening with
 the adapter receiving a shaft on an opposite end for rotating the shaft.
 The shaft may be connected to a valve for actuating the valve, for
 example.
 It is an object of the present invention to provide a device for tensioning
 studs which is easily positioned about a nut on the stud for rotation of
 the nut to a desired tensioning of the stud.
 Another object of the invention is to provide such a tensioning device
 which is particularly adapted for subsea use and operation from a remotely
 operated vehicle (ROV).
 SUMMARY OF THE INVENTION
 The present invention is directed to a torque applying apparatus having a
 torque applying device or tool including a worm gear on a drive shaft for
 engaging and rotating a toothed gear having a central opening receiving a
 male hexagonal member such as a nut or bolt head. The drive shaft extends
 axially in a direction perpendicular to the longitudinal axis of the stud.
 An extending end of the drive shaft has a drive connection for releasable
 connection to a drive motor, such as an electric hydraulic or electric
 pneumatic motor, for rotation of the drive shaft and nut. The central
 opening of the gear corresponds in shape to the nut for receiving the nut
 with the planar surfaces defining the opening engaging corresponding
 surfaces of the nut.
 The worm gear has a central outer concave periphery including a helical
 thread engaging in meshed relation the outer surfaces of teeth about the
 toothed gear for driving rotation of the gear. The direction of rotation
 of the toothed gear and nut may be reversed by reversal of the rotation of
 the fluid motor within any repositioning of the tool. A predetermined
 driving force may be provided by the drive motor and the drive shaft may
 be easily engaged and driven by a suitable drive motor from a ROV in a
 subsea environment such as required for subsea wells on the sea floor.
 Various sizes of toothed gears and worm gears may be provided for
 different nut sizes and different stress limits for the studs. One
 embodiment of the invention utilizes a nut drive for an extension socket
 or the like for exerting a torque on another nut or rotatable member.
 Other features and advantages of the invention will be apparent from the
 following specification and drawings.

DESCRIPTION OF THE INVENTION
 Referring now to the drawings for a better understanding of this invention,
 and more particularly to the embodiment shown in FIGS. 1-4, a generally
 schematic showing of the torque applying apparatus of the present
 invention is shown at 10 in FIG. 1. Torque applying device or tool 10 is
 shown as fitting about a nut N on a threaded end of stud S which extends
 upwardly through an opening in flange F. Stud S which is secured to a
 subjacent flange is tensioned a predetermined amount upon rotation of nut
 N in one direction. Torque applying device or tool 10 easily receives nut
 N and is supported on the upper surface of flange F. Studs S and nuts N
 are normally spaced at arcuate intervals along flange F with adjacent nuts
 N having corners spaced from each other a distance between about one half
 (1/2) inch and two (2) inches. Tool 10 is designed to easily fit between
 adjacent nuts N as shown in FIG. 1.
 Tool 10 has a body or housing 14 including a rectangular body portion 16
 and an integral arcuate body portion 18 extending from rectangular body
 portion 16. Body portion 14 has an axial bore 20 extending therethrough
 and arcuate body portion 18 has an axial bore 22 extending therethrough at
 right angles to bore 20. Bores 20 and 22 intersect as shown in FIG. 3 for
 communication of bores 20 and 22.
 A gear generally indicated at 26 fits within opening 22 and has a plurality
 of teeth 28 about its outer periphery 24. Each tooth 28 has a pair of
 inclined side surfaces 29 and an outer arcuate surface 30. Teeth 28
 adjacent the juncture of bores 20 and 22 project within bore 20 as shown
 in FIG. 3. Gear 26 has a central opening 32 of a hexagonal configuration
 or contour defined by flats or planar surfaces 34 to receive hexagonal nut
 N thereon. The height of gear 26 as shown in FIG. 4 is less than the
 height of nut N so that gear 26 may be positioned over nut N at any
 location. Opening 32 can obviously be formed of any desired shape
 conforming to the shape of nut N. Gear 26 is supported within bearings 36
 received within opening 22 for rotation of gear 26.
 Mounted within bore 20 for driving rotation of gear 26 is a worm gear
 generally indicated at 38 having a helical thread 39 and mounted on a
 drive shaft 40. Drive shaft 40 has opposed end shaft portions 42 and 44.
 End shaft portion 42 is received within a flanged bearing 46 which is
 mounted within an end cap 48 secured by bolts 50. End shaft portion 44 is
 supported within a flanged bearing 49 and has an end drive connection 52
 with planar surfaces received within an inner end of socket member 54.
 Socket member 54 has an outer end socket 56 receiving an end drive member
 58 having a splined end connection 60 for engagement with a suitable drive
 motor shown at broken lines at 61 in FIG. 1 for rotation of end drive
 member 58, socket member 54, and drive shaft 40 for rotating worm gear 38.
 Socket member 54 and end drive member 58 are mounted within a motor
 adapter housing generally indicated at 62 having an end flange 64 bolted
 to housing 16 by bolts 65. Housing 62 has a splined end 66 and an annular
 abutment 68 adjacent splined end 66. Drive motor 61 has an end meshing
 with splined end 66 and positioned against abutment 68 for proper mating
 of drive motor 61 onto spined end 60. Rotation of drive shaft 40 rotates
 worm gear 38 and tooth gear 26 for rotation of nut N.
 Operation
 In operation, torque applying or tensioning device 10 is positioned over a
 nut N to be rotated for tensioning a threaded stud S threaded onto nut N.
 Nut N is received within opening 32 of gear 26 with the lower surface of
 tensioning device 10 supported on the upper surface of flange F as shown
 in FIG. 1. In this position, fluid motor 61 is fitted over splined end 66
 with splined outer end connection 60 meshing with a drive member of motor
 61 for rotating outer end connection 60 thereby to rotate worm gear 38 and
 toothed gear 26 for tensioning stud S under a predetermined force. Upon
 tightening of nut N to the desired force level, tool 10 is removed and may
 be positioned over an adjacent stud until all of the studs S for a flanged
 connection have been tensioned to the desired force level. A suitable
 drive motor is sold by Air Tool of Houston, Texas under Model 55 RNRT-2T.
 Embodiment of FIGS. 5 and 6
 Referring to the embodiment shown in FIGS. 5 and 6, torque applying tool 10
 is illustrated for use with a separate drive adapter shown generally at
 100. Tool 10 is identical to the tool of FIGS. 1-5 except for drive
 adapter 100. Drive adapter 100 has an adapter body or nut 102 thereon
 which fits within hexagonal opening 32 of gear 26. Adapter body or nut 102
 has an integral flange and an integral square drive connection 106
 extending outwardly from flange 32 adapted for fitting within a socket for
 a suitable extension tool. Nut 102 has a threaded opening 108 therein and
 an externally threaded bolt 110 is bottomed within opening 108. A washer
 112 receives bolt 110. Thus, washer 112 and bolt 110 rotate with nut 102.
 The socket extension tool (not shown) is utilized for rotating a nut or
 other member to be driven. Thus, nuts that may be inaccessible to the tool
 as shown in FIGS. 1-4 are accessible to the arrangement shown in FIGS. 5
 and 6 with the use of a suitable extension socket. A single drive nut 102
 may be utilized for rotation of different sizes of nuts within a desired
 power range.
 Another adapter (not shown) similar to adapter 100 may be utilized with a
 socket end instead of drive connection 106 with the socket end receiving a
 shaft for rotating a separate member, such as a valve. Such an arrangement
 is particularly adapted by subsea use by an ROV.
 From the above, a stud tensioning tool 10 has been provided utilizing a
 driving connection provided between a worm gear 38 and a toothed gear 26
 for rotation of a nut in a desired direction. Worm gear 38 has a helical
 thread 39 with a center concave shape for engaging the outer teeth 28 of
 adjacent toothed gear 26 for driving gear 26. Gear 26 may be rotated in
 opposite directions by reversing hydraulic motor 61.
 While preferred embodiments of the present invention have been illustrated
 in detail, it is apparent that modifications and adaptations of the
 preferred embodiments will occur to those skilled in the art. However, it
 is to be expressly understood that such modifications and adaptations are
 within the spirit and scope of the present invention as set forth in the
 following claims.