Abstract:
A structure and method for a locking nut with a deformable member is provided. The locking nut has an elongated body relative to a comparable standard non-locking nut, allowing the nut to provide a standard length of thread for engaging bolt members while also defining a void for carrying the deformable locking member. The void has a forged side-wall structure that substantially engages the locking member within the void while shipping or handling the lock nut. The locking member deforms and flows into thread areas, thereby providing locking and vibration dampening functions, and also deforms or flows into the side-wall structures, thereby enabling the lock nut to impart sufficient frictional forces to the member to remove the deformed member from an assembly when the nut is removed. The locking forces imparted to the structure by the member may be varied and, therefore, increased by user-applied forces.

Description:
BACKGROUND OF THE INVENTION 
   Fastening objects together through methods incorporating threaded nut and bolt structures is well known. Typically, a male-threaded bolt projection from a first item is passed through an aperture in a second item, and a threaded nut is rotated onto the bolt projection until the bolt tightly compels the second item against the first item to form an assembled structure. Problems arise in maintaining the integrity of the resultant structure, as well as the individual components. For example, operational vibrations from use of the resultant structure may become translated into rotational movement of the nut relative to the bolt that loosens the bolt. Using a deformable insert component to provide a locking effect upon the threads of the nut and bolt assembly is well known in the art. One example is U.S. Pat. No. 3,938,571 to Heighberger for a “Nut with Sealing Insert.” Alternatively, rigid metallic locking devices have been used, which apply frictional locking forces upon the bolt member threads. An example of this type of device is U.S. Pat. No. 4,069,854 to Heighberger for “Locknut with Segmental Locking Elements.” 
   However, the prior art methods and structures have structural and functional disadvantages. Significantly, in the prior art, nut thread area is lost in order to allow for insertion of the locking element. For example, a conventional two-inch thread-nut has two inches of total body length and thread length along its central axis C. The prior art two-inch bolt with locking component also has two inches of total body length, but formation of a mounting void for containing the locking component results in a corresponding reduction of thread length. This shortening of thread length results in a reduction in structural strength in the nut which, in turn, results in a higher rate of nut thread failure when compared to a nut with a conventional (and therefore longer) thread length. Although the reduction in strength is dependent upon other factors, such as type of assembly and nut materials, it has been found that, as a general rule, a 25% reduction in thread engagement length can result in a 25% reduction in performance strength of a nut. 
   Another disadvantage with structures and methods utilizing a rigid locking insert is that the rigid member distorts the bolt threads through compressive force. This distortion results in damage to the bolt, which cannot be reused, and, therefore, the assembly cannot be disassembled and reassembled. This type of assembly is only useful for a single use or permanent installation, and is not available for uses that may require disassembly and re-assembly. 
   A further disadvantage of the prior art locking members is that a structural retaining element must physically and firmly retain the member within a member-carrying void during shipping and transport of the lock nut; otherwise, the member may become separated and lost. Similarly, a retaining structure is also needed to hold the member in place within the member-carrying area of the lock nut while the nut is being rotated about a threaded bolt member, and importantly during removal of the nut from the bolt. Prior art nuts, such as the aforementioned Heighberger “Nut with Sealing Insert”, utilized a machine-knurled edge to “grip” the member during transport, application and removal. However knurl patterns formed by machining techniques have limited knurl element height, width and depth dimensions and, consequently, limited member retaining capabilities. The member often becomes separated and may be lost during shipping. More importantly, the “gripping” abilities of the machine-knurled patterns are limited and insufficient to impart the frictional forces required to rotate and remove the deformed member from a bolt as the nut is rotated off of a bolt. Consequently, a user must find another mechanical means to engage and remove the deformed member from the bolt, resulting in greatly increased time for removal and disassembly. 
   Other prior art nuts utilize a cap member element, which is formed over a portion of the top surface of the locking member and holds the member within a carrying void, to retain the member during transport, removal and disassembly. An example of such a prior art nut is the ESNA® NU locknut. The ESNA cap member also exerts frictional forces upon the surface of the member to help compel it to rotate about a threaded bolt as the nut is rotated about the bolt. It is readily apparent that such a structure requires an additional sacrifice of effective thread length by consuming corresponding nut body material for the formation of the cap member. Also, the presence of this fixed and rigid cap structure makes replacement of an individual locking member impossible and, where the member has been degraded or failed, the entire nut must be discarded and replaced. 
   Additionally, it is the compressive interaction of the projections, member-carrying void and the bolt threads that causes the deformable ESNA member to impart locking characteristics to the ESNA lock nut. As a result, the deformable member cannot freely rotate about the bolt threads, but instead must deform as it travels about the bolt. This deformation results in a great deal of frictional force that must be overcome as the ESNA nut is threaded onto or off of the bolt. Similarly, the member must deform and becomes structurally altered immediately upon application of the nut onto a bolt. 
   Furthermore, the frictional force exerted upon the bolt threads by the ESNA-type locking member is limited to a constant value resulting from the compressive forces exerted upon the member through the cap/void wall/bolt thread interaction. This frictional force value reaches a maximum value once the bolt threads engage the entire thread-engaging inner surface of the deformable member. It is apparent that this value will not be increased by further tightening of the nut upon either the bolt or upon a workpiece disposed about the bolt, since this tightening will not increase the compressive forces imparted to the member by the cap/void wall/bolt thread interaction. Moreover, as the deformable member travels along the bolt threads, frictional abrasion from the bolt threads degrades the deformable member. Therefore, the maximum frictional force value imparted by the deformable member upon the bolt threads decreases every time the nut is tightened or loosened about a bolt member. Eventually, the member will be degraded beyond a point of meaningful frictional engagement with the bolt threads and, since the ESNA nut structure does not provide for replacement of the deformable member, the entire nut and member assembly must be discarded and replaced. Therefore, the prior art ESNA-type nut is not preferred for applications requiring a large travel distance along the bolt threads for application, nor for those applications requiring disassembly and re-assembly of the nut/bolt structure. 
   Another desired characteristic is a vibration dampening function. The other prior art nuts limit their vibration-dampening characteristics to absorbing vibrations between the thread bodies of the nut and bolt. This type of dampening may be insufficient in some applications, and additional vibration dampening devices may be required between nuts and workpieces in order to ensure that the prior art lock nuts remain in a fixed position when the assembly is subject to operational vibrations. 
   What is needed is a locking nut that has the thread engagement strength of a comparable standard non-locking nut. What is also needed is a locking member that does not distort and thereby damage the threads of the nut or bolt member. The nut must also retain the locking member during shipping and transport, and during rotation about a bolt and, more importantly, during removal of the nut from an assembly. What is also desired is a locking member that freely travels over bolt member threads until the member reaches a locking engagement point, thereby avoiding degradation of the member during assembly and disassembly. It is also desired that the lock nut provide vibration-dampening qualities beyond the thread engagement areas and including the nut-to-workpiece interface, in order to provide adequate locking and vibration dampening and resisting characteristics. And lastly, it is desired that the a user may vary the amount of locking force required to lock the locking nut in position, and thereby also vary the force imparted to the final assembly by the locking member. 
   SUMMARY OF THE INVENTION 
   A structure and method for a locking nut with a deformable member is provided. The locking nut has an elongated body relative to a comparable standard, non-locking nut. The elongated body allows the nut to provide a standard length of thread for engaging bolt members, while also defining a void for the receipt and retention of the deformable locking member. The member-carrying void has a forged gear-shaped sidewall structure that substantially engages the locking member within the void while shipping or handling the lock nut, and also causes the member to rotate with the nut as the nut is rotated onto a bolt member. Imparting rotational force to the lock nut when engaged in a nut-workpiece-bolt assembly may compel the locking member to deform and flow into thread areas, thereby providing locking and vibration dampening functions. The member may also deform or flow into the gear-shaped side-wall structures, thereby enabling the lock nut to impart sufficient frictional forces to the member to remove the deformed member from an assembly when the nut is removed. The member may also deform into a void between the workpiece and the nut and thereby provide a vibration-dampening interface between the nut and workpiece. The locking forces imparted to the structure by the member may be varied and, therefore, increased by user-applied forces. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a top plan view of a lock nut according to the present invention. 
       FIG. 2  is a side sectional view, taken about on the line  2 — 2  of  FIG. 1 , of the lock nut of  FIG. 1  and incorporating a sectional view of an inserted locking member according to the present invention. 
       FIG. 3  is a top fragmentary detail plan view of the lock nut of  FIG. 1  illustrating spline elements according to the present invention. 
       FIG. 4  is a top plan view of a locking member according to the present invention. 
       FIG. 5  is a sectional view, taken about on the line  4 — 4  of  FIG. 4 , of the member of  FIG. 3 . 
       FIG. 6  is an enlarged side sectional fragmentary view of an assembly of a locknut and locking member according to the present invention, a workpiece threaded bolt and an engagement workpiece. 
       FIG. 7  is another view of the assembly of  FIG. 6 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1 , a top-end view of an embodiment of a lock nut  10  with threads  12  according to the present invention is illustrated.  FIG. 2  is a side sectional view, taken about on the line  2 — 2  of  FIG. 1 , of the lock nut of  FIG. 1 . As is conventional, the nut  10  has six exterior side-walls  14  for engagement with tools for rotational application about a mating threaded bolt workpiece (not shown), although it is readily apparent that other side-wall configurations are suitable, and the invention is not limited to lock-nuts with six exterior sidewalls. Between the exterior side-wall  14  and the threads  12 , a locking member-carrying aperture  16  is defined. The aperture  16  is a locking member carrying region bounded by a splined circular interior sidewall element  18  and an actuating wall  24 , and extending into space above the top surface  62  of the locknut  10 . The splined side-wall  18  is defined by a series of vertical splines  20 , each spline  20  preferably about parallel to a central axis C of the nut  10  and located along a radius R about the axis C, wherein the threads  12  and the actuating wall  24  are also defined radially about the same axis C. The actuating wall  24  is defined between the bottom ends  22  of the splines  20  and the threads  12 . 
   Although the present embodiment of the spline  20  is parallel with the central axis, this alignment is not required and alternative alignments of the splines will be apparent to one skilled in the art. For example, the splines may taper inwardly (not shown) with respect to the central axis as one views the splines from the top surface. This configuration would enable easier insertion or removal of a deformable member from the locknut of the present invention. Alternatively, the splines may taper outwardly (not shown) with respect to the central axis as one views the splines from the top surface. This latter configuration would facilitate retention of a deformable member, compressed and flowed according to the present invention within the member-carrying aperture when the locknut is loosened and removed from a workpiece bolt. 
   Referring now to  FIG. 2 , a side sectional view of the nut  10  of  FIG. 1  is provided, incorporating a sectional view of an inserted locking member  30  according to the present invention. Although, in the present embodiment, the aperture  16  has a conical portion  17  defined by the conical shape of the conical actuating wall  24  and a cylindrical splined aperture wall portion  19  defined by the parallel orientation of the splines  20  along the central axis C, other wall  18  and  20  shapes may be practiced by the present invention, and the invention is not limited to these specific shapes. For an example, an alternative actuating wall (not shown) may have a flat circular shape parallel to the radius R. Similarly, alternative splines (not shown) may have an orientation other than parallel to the central axis C, as described above. Accordingly, the embodiment of the invention described is exemplary of the invention, and the invention is not limited to the embodiment illustrated in the figures. 
   A conventional non-locking nut typically has a thread length roughly equivalent to the thread size. Accordingly, a two-inch thread-nut has two inches of thread length along its central axis. Prior art lock nuts (not shown) are typically formed from standard non-lock nuts by creating a locking insert void within the nut body, and the formation of the void necessarily results in a corresponding loss of thread length. This shortening of thread length results in a reduction in structural strength in the nut which, in turn, results in a higher rate of nut thread failure when compared to a non-locking nut with a conventional (and therefore longer) thread length. Although the reduction in strength is dependent upon other factors, such as type of assembly and nut materials, it has been found that, as a general rule, a 25% reduction in thread engagement length can result in a 25% reduction in performance strength of a nut. 
   Referring again to  FIG. 2 , one important advantage the present invention is that the total thread length TL is about equivalent to the thread size W. This is accomplished by forming the locknut  10  from a nut body with a greater body length than a conventional prior art locknut or non-locking nut. Aperture  16  is formed within a portion of the locknut  10  having an aperture length dimension IL, which results in an overall locknut length BL that is the sum of the thread length TL dimension and the aperture length dimension IL. Accordingly, the locknut  10  has about the same thread strength as a convention non-lock nut, and greater thread strength than prior art lock nuts, which have a diminished thread length dimension. 
   As illustrated in  FIG. 2 , the splines  20  have a length dimension SL. Referring now to  FIG. 3 , a partial view of the splined aperture wall  19  is provided. The splines  20  shown in  FIG. 3  have a preferred gear shape and array structure, although other shapes and array structure may be practiced with the present invention. The geared splines  20  have a depth dimension SD between each spline tip  40  and spline base  42 . The splines  20  also define an angle A between adjacent spline walls  44 , and further define spline voids  21  between adjacent spline walls  44 . The preferred depth dimension SD and angle A dimensions will vary depending upon the size of the locknut  10 , the application of the locknut  10  and the type of deformable locking member  30  utilized with the locknut  10 . 
   Although the spline  20  embodiment described thus is of a pointed triangular shape with uniform dimensions SD and SL and wall angles A, and is distributed uniformly around the entire circumference of the splined aperture wall  19 , the invention is not limited to this configuration. For example, some applications of the invention may not require that the entire circumference of the splined aperture wall  19  be comprised of splines. Instead, a limited distribution of splines may be spaced about smooth aperture wall portions (not shown). Alternatively, splines may be grouped in discrete clusters (not shown) separated by smooth aperture wall portions. The exact number of splines  20  or distribution of splines  20  is not important to the invention. What is important is that a sufficient number of splines  20  are provided, and that the splines  20  have sufficient depth dimensions SD and length dimensions SL to ensure that the deformable locking member  30  is fly engaged by the splines  20 . 
   A preferred embodiment of the deformable member  30  is formed from a resilient plastic material, such as a polypropylene or a polytetrafluoroethylene, which have excellent qualities of elastic memory and are well suited for low-temperature applications. Polypropylene has a high melting point, low density, excellent environmental stress crack resistance and chemical resistance, and provides a good barrier to moisture, grease or oil. It is preferred for application operating temperatures below 225 degrees Fahrenheit (° F.). For higher temperatures, up to 500° F., a polytetrafluoroethylene material, such as Teflon®, is preferred. Alternatively, where the nut applications may be subject to high temperatures above 500° F., the deformable member  30  may be formed from a soft metal, such as a copper or aluminum metallic compound. For example, where operating temperatures may rise above 500° F., polytetrafluoroethylene would liquefy and, therefore, would not be suitable. A copper or aluminum compound, however, may be soft enough to deform and provide the vibration and locking characteristics described above, and yet maintain solid characteristics at high temperatures. 
   It is important that the splines  20  firmly engage the deformable member  30  and thereby hold the member  30  within the member-carrying aperture  16  during shipping and during application of the locknut  10  to a bolt and workpiece. The tips  40  of the present embodiment are pointed, and define a tip array diameter  46  about the central axis C which is less than that of the outer deformable member diameter  48 . The member  30  is pressed into the aperture  16 , causing the tips  40  to impinge into the outer surface  50  of the member  30 . It is important that the member  30  has an inherent resilience that causes the outer surface  50  to impart reactive expansion forces against the impinging tips  40 . The interaction of the tips  40  and the outer surface  50  results in frictional forces that retain the member  30  within the aperture  16  while the nut  10  is being shipped, transported or otherwise handled. 
   Referring now to  FIGS. 4 and 5 , the inner surface  52  of the deformable member  30  is of a cylindrical shape, shaped about a central axis CM common to the cylindrical outer surface  50 . It is preferred that the member axis CM is aligned with the nut central axis C when the member  30  is inserted into the aperture  16 .  FIG. 6  illustrates an assembly of the locknut  10 , the locking member  30 , a workpiece threaded bolt B and an engagement workpiece E. It is also preferred that the inner surface  52  have a diameter greater than the thread size W of the locknut  10 , thereby creating a space  64  between the inner surface  52  and the workpiece bolt threads BT. Therefore, when the locknut  10  and inserted deformable member  30  are rotated about the bolt B, the deformable member  30  will not engage the bolt threads BT. Moreover, the member  30  will pass over the bolt threads BT without frictional interaction or rotative restraint imparted to the member  30  and locknut  10  assembly by engagement of the deformable member  30  with the bolt threads BT. This is important in preventing degradation or wear effects upon the member inner surface  52  by application or removal of the member  30  and locknut  10  assembly to or from the bolt B. 
     FIG. 7  shows the assembly of  FIG. 6 , wherein the locknut  10  has been tightened about the bolt B sufficient to cause the deformable member upper surface  60  to engage the workpiece bottom surface EB, and the deformable member bottom surface  70  to engage the actuating wall  24 . As the locknut  10  is further tightened about the bolt B, the member  30  is compressed by the actuating wall  24  and the engagement workpiece bottom surface EB, causing the member  30  to deform and cold-flow into spaces  64 , the bolt threads BT, the spline voids  21 , and into the interface region  17  defined between the workpiece engagement bottom surface EB and the locknut  10  upper surface  62 . 
   The compressed and cold-flowed member  30  thereby forms thread-engaging regions  66 . The thread-engaging regions  66  impart a resilient expansion force against the bolt threads BT and a corresponding frictional force that resists movement of the bolt threads BT relative to the member  30 . The same resilient expansion forces are imparted by the compressed and deformed member  30  against the locknut  10  actuating wall  24 , the splines  20 , and the locknut threads  12 , and therefore the same corresponding frictional force that resists movement of the locknut  10  relative to the member  30 . Additionally, referring again to  FIG. 3 , the spline walls  44  exert normal force vectors V against portions of the deformable member  30  flowed into the spline voids  21  responsive to rotation forces exerted upon the deformable member  30  relative to the locknut  10 . Accordingly, the deformed and flowed member  30  provides locking forces that “lock” the locknut  10  into place relative to the bolt B and workpiece E. 
   Moreover, a resilient plastic material with elastic memory is particularly preferable in order for the deformable member  30  to relax slightly when the nut  10  is loosened. By relaxing, the frictional forces imparted by the deformable member  30  against the bolt threads BT are reduced sufficiently to allow the member  30  to move relative to the bolt threads BT as the locknut  10  is loosened about the bolt B. Although the frictional forces exerted against the bolt threads BT by the member  30  are reduced, the portions of the member  30  that flowed into the spline voids  21  are still firmly engaged by the spline walls  44  and, accordingly, the member  30  is compelled by the splines  20  to rotate with the locknut  10  as the locknut  10  is loosened about the bolt B. The greater the elastic memory and resiliency of the deformable member  30 , the greater the ability of the deformable member  16  to be reused in further applications. One embodiment of a plastic deformable member according to the present invention comprises polypropylene. Other embodiments are comprised of Teflon. Other suitable plastic materials will be readily apparent to one skilled in the art. 
   As shown in  FIG. 7 , it is preferred that a sealing and insulating portion  68  of the member  30  flows into the interface region  17 . This insulating portion  68  thereby serves as a sealing and vibration-dampening interface between the locknut  10  and workpiece E. The preferred thickness of the insulating portion  68  sufficient to provide insulating and/or sealing characteristics will depend upon the size of the locknut  10  and the desired application. For example, for a two-inch locknut  10  with a polypropylene locking member  30 , an insulating portion  68  having a thickness of about one-sixteenth inch has been found to provide good vibration dampening characteristics. However, a greater insulating portion  68  thickness may be desired for applications subject to greater vibration forces, and the one-sixteenth inch thickness is only illustrative of one possible embodiment. If desired, the nut upper surface  62  may be knurled or splined (not shown), in order to provide additional locking characteristics resultant from increasing frictional resistance to rotational movement of the insulating portion  68  relative to the locknut  10 . 
   In practicing the invention, the locknut  10  is tightened against the workpiece E sufficient to flow the member  30  into bolt thread regions  64 , and into the interface region  17  to form the insulating portion  68 . The resiliency of the member  30  exerts expansion forces against the constraining and deforming elements: the bolt threads BT, workpiece engagement bottom surface EB, the locknut upper surface  62 , actuating wall  24  and splined side-wall  18 . The locking characteristics of the deformable member  30  are proportionate to the expansion forces exerted by the member  30  against these restraining elements. The expansion forces exerted by the deformed member  30  may be increased by further tightening the locknut  10  about the bolt B, which increases the compressive forces acting upon the member  30  by the constraining and deforming elements and, therefore, the reactive expansion forces by the member  30 . Some of this force will be translated into additional member  30  material flowing into the interface region  17 . But the interaction of the cold-flow fluid dynamics of the member  30  and the decreasing size of the interface region  17  will limit the amount of force dissipated by material flow of the member  30  into the interface region  17 . Accordingly, a portion of the increased compressive forces acting upon the member  30  will be translated into additional expansion forces exerted by the member against the constraining elements. In this manner, the locking forces imparted to the structure by the deformable member may be varied and increased, an improvement over the prior art ESNA® type of locknut. 
   In order to ensure that sufficient material will cold-flow into the thread regions  64  and interface region  17 , it is necessary that the locking member  30  have a dimensional volume size larger than the volume of the member-carrying aperture  16 . The excess material volume will provide the material deforming and flowing into the thread regions and interface region  17 . Accordingly, the preferred dimensional size of the deformable member  30  relative to the aperture will depend upon the size of the locknut  10 , the size of the bolt thread region engaged by the deformed material, and the desired size of the interface region  17  (if any). 
   Another important feature of the present invention is that the locking member  30  rotates and remains engaged with the locknut  10  when the locknut  10  is loosened and removed from the bolt B. This enables the rapid removal of the member  30  with the locknut  10  and, accordingly, rapid disassembly of the member  30  and locknut  10  from the workpiece assembly. In contrast, prior art deformable locking inserts typically remain engaged and secured about the bolt and workpiece interface when the prior art locknut is removed. 
   As discussed in the background of the invention material, prior art nuts, such as the aforementioned Heighberger “Nut with Sealing Insert”, utilize a machine-knurled edge to “grip” the member during transport, application and removal. However knurl patterns formed by machining techniques have limited maximum knurl element height, width and depth dimensions, due to the problems inherent in machining patterns within the relatively small member-carrying voids. Only a relatively small portion of the knurling tool can fit within the void and, accordingly, only small-dimensioned knurls can be formed without damaging the prior art locknut. Most importantly, a knurl applied through a machining means has a limited depth within an insert carrying void, limiting the prior art knurl pattern to only that portion of the insert carrying void near the surface of the void. Consequently, the “gripping” abilities of a machine-knurled pattern is limited and insufficient to impart the frictional forces required to rotate and remove the deformed member from a bolt as the nut is rotated off of a bolt. 
   What is new in the present invention is forming of substantial member-engaging elements by a forging process. The present invention can be practiced with either hot or cold forging techniques. What is important is that member-engaging elements of a substantial depth and height are formed, so that the deformable locking member cold-flows about the member-engaging elements and engages them substantially. Therefore, when a locknut according to the present invention is removed from a bolt and/or workpiece, the deformable member remains substantially engaged by the locknut and is removed along with it. 
   Referring again to  FIG. 2 , an embodiment of a deformable member-engaging element is illustrated, the gear shaped splines  20 . The spines  20  have a substantial height SL. The height SL is determined by the size of the locknut  10  and the size of the deformable insert  30 . For a two-inch locknut according to the present invention, an exemplary height SL is about three-sixteenth of an inch. For a half-inch locknut, a spline height SL of about one-sixteenth of an inch is preferred. The splines  20  define the circular interior sidewall element  18  and, accordingly, it is preferred that the height of the circular interior sidewall element  18  is about the same as the spline height SL. 
   Prior art knurl patterns are generally of a shallow surface depth, due to the limitations of machining technology. The forged gear-shaped splines  20 , according to the present invention shown in  FIG. 3 , have substantial triangular shaped spline voids  21  defined by substantial spline depth SD and tip-to-tip TD dimensions. The spline tips  40  are preferably of a pointed form. This pointed tip form enables the splines  20  to pierce into the outer deformable member surface  50  when the member  30  is pressed into the aperture  16 , since the tip array diameter  46  is less than that of the outer deformable member diameter  48 , as discussed earlier. The pointed tips  40  also pierce into the member  30  when the member is compressed against the splines  20  as the locknut  10  is tightened against the bolt B and workpiece E, thereby urging the cold-flowing of the member  30  into the voids  21 . The triangular shape of the voids  21  imparted by the straight and smooth linear planar shape of the spline sidewalls  44  enables the member  30  to deform and fill virtually the entire void  21 . This ensures that enough of the deformable member  30  flows into the voids  21  so that the member  30  is firmly engaged by the locknut  10  as the locknut  10  is loosened and removed from the bolt B and workpiece E. The pitch, angle A and spline height SL values enabled by the forging process according to the present invention are substantially greater than those attainable by prior art knurling processes. It is preferable that the angle A has a value selected from the range of about 60 degrees to about 120 degrees, and that the pitch of the spline tips  40  per inch is a value selected from the range of about 10 to about 24. A preferred exemplary two-inch locknut according to the present invention has an angle A value of about ninety degrees, and a spline tip  40  pitch of about 14. However, preferred values will change based upon the size of the locknut; for example, for locknuts larger than two-and-one-half inches, a preferred pitch for a plastic deformable insert is about 10. For locknuts below one-inch in thread diameter, it is preferred that cold-forging processes are used to form the splines. For locknuts above one-inch in thread diameter, it is preferred that hot-forging processes are used. 
   It is also well known in the arts that structures formed by forging have a superior integrity to those structures formed by machining. The act of machining a knurl pattern creates knurl structures by substantially removing material from the nut body through cutting forces. In contrast, forming the splines  20  through a forging process results in material being compressed into the desired shape by a stamping action. This results in an increased material density in the forged spline and actuating wall areas, resulting in a corresponding increased structural integrity of the spines  20  as compared to prior art knurl structures. 
   While preferred embodiments of the invention have been described herein, variations in the design may be made, and such variations may be apparent to those skilled in the art of making tools, as well as to those skilled in other arts. The materials identified above are by no means the only materials suitable for the manufacture of the tool, and substitute materials will be readily apparent to one skilled in the art. The scope of the invention, therefore, is only to be limited by the following claims.