Patent Publication Number: US-2021180638-A1

Title: Wing nut

Description:
TECHNICAL FIELD 
     This patent disclosure relates generally to pumping conduits and, more particularly, to wing nuts used to connect conduit sections for pumping operations. 
     BACKGROUND 
     Pumping operations using conduits in which high, cyclically applied stresses are known. For example, pumping operations in industries like hydraulic fracking (or “fracking”), concrete pouring, well service, and others, include pumps that send fluids having high viscosity and/or under large pressure through conduits. The conduits are typically made from pipe sections that are connected to one another using threaded nuts. The nuts include wings that provide the ability to apply torque to tighten or loosen the nuts, often by use of a sledge hammer or a hydraulic hammer to provide the large impact loading or toque required to install or uninstall the nuts. 
     Traditionally, wing nuts for such pumping operations are known to have a limited service life due to the extreme conditions of their use and installation. Often, the wings on nuts become deformed from repeated loading during nut installation. Additionally, the nuts are prone to cracks when the pipe segments they are used to connect are subject to bending loads, and to fatigue failures when subjected to cyclical pressure loading from the incompressible fluid being pumped at high pressure within the pipe segments. 
     One example of a known wing nut can be seen in WO 2016/205208 (“Witkowski”), which describes a wing nut having a “full root radius” and an “increased wall thickness.” While the wing nut of Witkowski may represent an improvement over known wing nuts, it is still ineffective in improving all aspects of use and operation of wing nuts. 
     SUMMARY 
     The disclosure describes, in one aspect, a wing nut. The wing nut includes a body having a generally cylindrical shape extending along a centerline. The body includes a sidewall that surrounds a central opening. The sidewall includes an outer peripheral surface having a front end and a rear end, and extending over a length along the centerline. The central opening is threaded along a threaded portion having a threaded length extending from the back end towards the front end, the threaded portion having a thread shape. At least two wings are integrated with the sidewall and extend away from the sidewall in a radial direction relative to the centerline. A rib extends peripherally around the sidewall, in a radially outward direction along an outer surface of the sidewall such that a wall thickness of the sidewall increases to a maximum value moving along the centerline away from the rear end, and decreases along the centerline moving towards the front end from the maximum value. The maximum value of the wall thickness is disposed at an axial location that overlaps an end of the threaded length. 
     In another aspect, the disclosure describes a wing nut. The wing nut includes a body having a generally cylindrical shape extending along a centerline. The body includes a sidewall that surrounds a central opening. The sidewall includes an outer peripheral surface having a front end and a rear end, and extending over a length along the centerline. The central opening is threaded along a threaded portion having a threaded length extending from the back end towards the front end. The threaded portion has a thread shape. Three wings are integrated with the sidewall and extend away from the sidewall in a radial direction relative to the centerline. Each wing has a curved outer face, which generally follows a circular shape of the sidewall. The thread shape includes a plurality of internal threads, each internal thread formed by an internal crest and a root portion. The internal crest is flat and the root portion is rounded such that the root portion is tangential to both adjacent thread flanks. The threaded portion terminates at a thread release undercut, which axially spans between the threaded portion and a flange. The flange is disposed adjacent the front end of the body. The body further comprises a guide bore defined axially between the flange and front end of the body. 
     In yet another aspect, the disclosure describes a wing nut. The wing nut includes a body having a generally cylindrical shape extending along a centerline. The body includes a sidewall that surrounds a central opening. The sidewall includes an outer peripheral surface having a front end and a rear end, and extends over a length along the centerline. The central opening is threaded along a threaded portion having a threaded length extending from the back end towards the front end, and has a thread shape. Three wings are integrated with the sidewall and extend away from the sidewall in a radial direction relative to the centerline. A rib extends peripherally around the sidewall. The rib extends radially outwardly along an outer surface of the sidewall such that a wall thickness of the sidewall increases to a maximum value moving along the centerline away from the rear end, and decreases along the centerline moving towards the front end from the maximum value. The maximum value of the wall thickness is disposed at an axial location that overlaps an end of the threaded length. Each wing has a curved outer face, which generally follows a circular shape of the sidewall. Each wing also has a corresponding lug centerline extending parallel to, but at an offset distance from, a corresponding radius of the central opening that intersects the centerline at a center point, and includes a forward facing side surface and a reverse facing side surface, the forward and reverse facing side surfaces being planar and each being parallel to the centerline. A width of each forward facing side face is larger than a width of each reverse facing side face. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1 and 2  are outline views from different perspectives of a wing nut in accordance with the disclosure. 
         FIG. 3  is a front view of a wing nut in accordance with the disclosure. 
         FIG. 4  is a side view of a wing nut in accordance with the disclosure. 
         FIG. 5  is an outline view from a front and side perspective of a wing nut in accordance with the disclosure. 
         FIG. 6  is a sectional view of a wing nut in accordance with the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure relates to pumping system conduits and, more particularly, to wing nuts for connecting segments of pipe or conduits such as those used in fracking, concrete pumping, well servicing and the like in the oil and gas, construction and other industries. In the embodiment illustrated herein, the wing nut is used on a hammer union for connecting two pipe segments that are used to transfer fluids under pressure during oilfield service or production operations. 
     One embodiment of a wing nut  100  is shown in  FIGS. 1 and 2  from a front and rear perspective to illustrate the major aspects thereof. The wing nut  100  includes a body  102  having a generally hollow cylindrical shape that includes a sidewall  103  and a threaded opening  104 . The sidewall  103  is ring-shaped and has a length, L, along an axial direction of a centerline, R, and a wall thickness, T, in a radial direction relative to the centerline R. The wall thickness T varies along the length L of the wing nut, as is described in the description that follows in further detail. 
     The wing nut  100  includes three lugs or wings  106  disposed along an outer surface  108  of the sidewall  103  disposed along equally spaced angles along the periphery of the sidewall  103 . Each of the three wings  106  extends axially along at least a portion of the length L of the body  102 . The body  102  forms a front annular face  110  and a rear annular face  112 , which are planar and perpendicular to the centerline R at either end of the body  102  in a lengthwise direction along the centerline R. The threaded opening  104  is surrounded by an internal threaded portion  114  and terminates at a flange  116  adjacent the front annular face  110 . 
     An outline view from a front perspective of the wing nut  100  is shown in  FIG. 3 . As shown in this view, each wing  106  has a generally trapezoidal shape defined between a forward facing side face  118  and a reverse facing side face  120 . During installation, a user may strike or otherwise engage the forward facing side face  118  and apply a force that produces a torque in a tightening direction to install the wing nut  100 , which in the orientation shown in  FIG. 3  would tend to turn the wing nut  100  in a clockwise direction. Similarly, striking or otherwise engaging the reverse facing side face  120  would produce a torque in a loosening direction to remove the wing nut  100 , which in the orientation shown in  FIG. 3  would tend to turn the wing nut  100  in a counter-clockwise direction. The shape of the wing  106  includes a curved outer face  122 , which generally follows the circular shape of the sidewall  103  instead of being flat or, stated differently, instead of being parallel to a tangent of the outer periphery of the sidewall  103 . 
     Each wing  106  has a corresponding lug centerline  124 , which extends parallel to, but is offset by a distance, D, from a corresponding radius  126  that extends to the center point, C, of the threaded opening  104 , which center point C also lies on the centerline R ( FIG. 1 ). In other words, the three lug centerlines  124  of the three wings  106 , if extended, would form an equilateral triangle (illustrated in  FIG. 3 ), the center of which would coincide with the center point C. Because of the offset D between the lug centerline  124  and the corresponding radius  126 , a width of the forward and reverse facing side faces  118  and  120  will differ, with a width W 1  of each forward facing side face  118  being larger than the width W 2  of each reverse facing side face  120 . As a consequence, the forward facing side faces  118  present a larger strike target to facilitate tightening during installation of the wing nut  100 . 
     Both the forward and reverse facing side faces  118  and  120  form an included angle, 2α, with the lug centerline, with each being disposed at an angle α relative to lug centerline  124 . In the illustrated embodiment, the angle α is 15 degrees, but other angles may be used. The selection of a larger included angle will act to lengthen the widths W 1  and W 2 . A larger offset distance D in the direction shown will lengthen the width W 1  and shorten the width W 2 . It should be appreciated that, in the event a larger width is desired in the loosening direction, the offset may be taken on the opposite side of the centerline, in which case the width W 2  will become larger than the width W 1  (not shown). Stated differently, the lug and wing nut would appear as a mirror image of the embodiment shown herein. 
     Selection of the offset distance D, and also the included angle, is a matter of design choice and depends on the dimension or ratio between W 1  and W 2  that is desired for a particular application. It should be appreciated that, in addition to presenting a larger target for striking the wing nut in a tightening direction, the offset location of the wings also serves in internally redirecting the direction of application of the tightening impulse force in a more tangential direction relative to the threaded opening  104 , which reduces internal stresses acting transversely within the sidewall  103 . It should also be appreciated that the curved shape of the curved outer face  122  strengthens the outer corners  128  of each wing  106  by increasing their included angle and material thickness at each corner as compared to a wing design having a flat or tangentially-extending outer surface relative to the threaded opening  104 . 
     Still in reference to  FIG. 3 , it can be seen that each forward-facing side of the wings  106  includes two raised ridges  130 , which can provide visual contrast. Of course, the shape, orientation and number of ridges  130  may be different than what is shown in  FIG. 3 . 
     To further increase the strength and resilience of the wing nut  100 , a rib  132  is disposed generally peripherally around the sidewall  103  at an axial location that lies generally at a termination of the threaded portion  114 . More particularly, and in further reference to  FIGS. 4, 5, and 6 , the rib  132  may extend entirely in segments between adjacent wings  106 , as shown by the dashed line  134  (shown in  FIG. 3 ), or it may alternatively be interrupted by radial depressions  136  in areas adjacent the forward facing side face  118 . As can be seen in  FIG. 5 , the radial depressions  136  decrease the height of the rib  132  to more readily provide access for the user to strike the forward facing side face  118  when installing the wing nut  100 , to improve accuracy of the strike onto that surface, and to reduce the frequency of corner-only strikes, which traditionally have been known to lead to damage of wing nuts. As can be seen from  FIG. 4 , and also  FIG. 6 , a side profile of the rib  132  indicates that the wall thickness T of the sidewall tends to gradually increase and then gradually decrease along the axial length L of the body  102 . A maximum thickness of the sidewall  103 , which is referred to herein as the rib  132 , is axially disposed around at a length of about 0.4*L from the front annular face  110 , but other locations may be used. In the illustrated embodiment, the maximum thickness is axially located to overlap an end of the threaded length of the threaded portion  114  along the centerline. 
     Referring now to  FIG. 6 , which illustrates a cross section through the wing nut  100 , it can be seen that the threaded portion  114  partially extends along an inner portion of the threaded opening  104  from the rear annular face  112  towards the front annular face  110  along the centerline R, and includes a plurality of internal threads. Each internal thread is made from an internal crest or inner diameter portion  138  and an outer diameter portion or root portion  140 . The threads are designed according to a modified thread standard, for example, a J-series screw thread, in which the inner diameter portion  138  is flat, but the root portion  140  is rounded such that the root becomes is tangential to both adjacent thread side faces or flanks. In this way, sharp roots are avoided, which can create stress concentrations, and fatigue strength of the wing nut is improved. 
     The threaded portion  114  terminates at a thread release undercut  142 , which as can be seen in  FIG. 6  axially spans between the threaded portion  114  and the flange  116 . The thread release undercut  142  is constructed to provide an unthreaded portion in which a leading portion of the mating inner thread (not shown) of the pipe segment (not shown) onto which the wing nut  100  will be installed may be disposed when the wing nut is installed to ensure that little deformation occurs in that area for a proper seating of the flange  116  against a blunt end flange of the pipe section. The thread release undercut  142  also provides clearance for a more precise cutting of the threaded portion  114 . A guide bore  144  is axially disposed between the thread release undercut  142  and the front annular face  110 . The guide bore  144  helps center and secure the wing nut  100  onto the pipe section (not shown) it connects. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure applicable to wing nuts for use when connecting pipe sections or segments. 
     It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.