Patent Publication Number: US-2019178282-A1

Title: Reaction washer with belleville spring induced radially inward progressing bottom bite action and tightening and securing system

Description:
RELATED APPLICATIONS 
     The present application is a continuation-in-part of U.S. application Ser. No. 16/150,633, filed Oct. 3, 2018, which is a continuation of U.S. application Ser. No. 14/932,768, filed Nov. 4, 2015, now U.S. Pat. No. 10,107,325, issued Oct. 23, 2018, both of which are incorporated herein by reference. The present application is also a continuation-in-part of U.S. application Ser. No. 15/605,876, filed May 25, 2017, which is incorporated herein by reference. If any disclosures are incorporated herein by reference and such incorporated disclosures conflict in part or whole with the present disclosure, then to the extent of conflict, and/or broader disclosure, and/or broader definition of terms, the present disclosure controls. If such incorporated disclosures conflict in part or whole with one another, then to the extent of conflict, the later-dated disclosure controls. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to reaction washers for transferring onto a base surface underneath a circumferentially received reaction torque resulting from actuating a nut or bolt head that is resting on the reaction washer. In particular, the present invention relates to reaction washers with belleville spring induced radially inward progressing bottom bite action and tightening and securing system. 
     BACKGROUND 
     Reaction washers are increasingly employed to transfer onto a base surface underneath a reaction torque that is resulting from actuating a nut or bolt head resting on the reaction washer. Prior Art Reaction washers have either planar arrayed serrations or circumferentially arrayed bite spikes on its bottom side for biting into the base surface underneath in order to transfer the reaction torque onto it. 
     It is imperative for proper function of the reaction washer that it never slips during the tightening phase during which the axial load on the reaction washer ramps up from an initial minimum to the final tightening load of the nut or bolt head above the reaction washer. To meet this requirement, the slippage resistance in between the reaction washer bottom and the base surface has to be at any time higher than the friction in the respective actuated thread interface. This is difficult to accomplish in a flat surface contact, since common threads have about 60 deg thread flank angle resulting in a normal force on the thread flanks and the corresponding friction force to be at least 13.3% higher than in between a flat surface pair of similar configuration. Hence, and in particular at the beginning of the torque wrench induced tightening phase with minimal loads and consequently in absence of serration biting, the mean diameter of initial bottom serration contact with the base surface is desirably substantially more than 13.3% larger than the mean thread diameter. This may be a suitable minimum for ideal surface conditions in between the reaction washer bottom and the base surface with to the surface conditions, Nevertheless, inadvertent contamination in the thread interface and presence of lubricant, paint or other friction reducing elements on the base surface may occur in field conditions. Therefore, there exists the need for a reaction washer and tightening system that provides an initial bottom serration contact area that is at a minimum and at a maximum distance from the reaction washer axis. The present invention addresses this need. 
     During initial manual assembly and preloading, sliding resistance in between the nut or bolt head and the reaction washer on one hand and in between the reaction washer and the base surface on the other hand are commonly similar in some prior art reaction washers. This may cause inadvertent sliding of the reaction washer on the base surface and debris or chip build up in the grooves in between bottom serrations during pre-tightening. The debris or chip build up in the grooves may result in an impaired biting action of the bottom serrations during following torque wrench assisted full tightening. Therefore, there exists a need for a reaction washer configuration that prevents inadvertent sliding and bottom serration clogging during initial manual pre-tightening. The present invention addresses also this need. 
     A prior art reaction washer of the present inventors has circumferential bite spikes or radially oriented serrations that are arrayed along the periphery of the washer bottom. Although such prior art reaction washer provides excellent initial bite, this reaction washer may be required to be within a predetermined height at which its structural stiffness may not be sufficient to completely distribute the load centrally received from the nut or bolt head onto the peripheral bottom serrations or spikes. In that case, the prior art reaction washer may collapse resulting in insufficient bite action towards the final tightening load. Therefore, there exists a need for a reaction washer that provides an initial bottom serration contact area that is at a minimum and at a maximum distance from the reaction washer axis and a final bottom serration contact area that extends radially substantially further inward towards the washer axis than the initial bottom serration contact area. The present invention addresses also this need. 
     A key function of conventional prior art reaction washers may also be to withhold the nut or bolt head from inadvertently loosening. For that purpose, well known Belleville washers are employed that have a flat conical shape and springily collapse upon receiving the tightening load and maintain resilient contact between the nut or bolt head above and the base surface beneath. A prior art reaction washer of the present inventors incorporates a Belleville body concentrically inside a planar washer portion with the bottom serrations. In this prior art reaction washer, the collapsing and springily resistance of the central Belleville body is limited by the radial extension of it. Therefore, there exists a need for a reaction washer with Belleville configuration that extends substantially into bottom serrations. The present invention addresses also this need. 
     Reaction washers feature torque receiving structures placed at the washer circumference. To transfer the reaction torque from a reaction socket onto them, the reaction socket commonly features a drain interface that couples in a torque transferring fashion with the torque receiving structures. To keep the coupling between reaction washer and reaction socket compact and within eventually very limited space available around the nut or bolt head to be tightened, it is desirable to have the drain interface and torque receive structures to snuggly fit. On the other hand, the collapsing of a Belleville spring causes angular displacement around its periphery, which may adversely affect a snug fit between torque receiving structures and drain interface. Therefore, there exists a need for a reaction washer and tightening system including drain interface and torque receiving structures that provide a snug fit that is insensitive to the displacement occurring during collapsing of a Belleville spring configuration of the reaction washer. The present invention addresses also this need. 
     A prior art reaction washer stack of the present inventors provides additionally against inadvertent loosening of a nut or bolt head by the means of a top washer resting via a helical ramp interface on a bottom washer. The helical ramp interface has a ramp pitch that is larger than a thread pitch of the respective nut or bolt such that upon inadvertent rotation of the nut or bolt the top washer is dragged along via its top serrations biting into the nut or bolt head while the bottom washer remains fixed via its bottom serrations biting into the base surface. Since the ramp pitch exceeds the thread pitch, inadvertent rotation in loosening direction of the thread interface increases tension of the nut or bolt head. Nevertheless, such prior art washer stacks require a certain stacking height which may exceed common heights of securing washer systems. Also, such prior art reaction washer stacks do not provide for an initial bottom serration contact area that is at a minimum and at a maximum distance from the reaction washer axis and a final bottom serration contact area that extends radially substantially further inward towards the washer axis than the initial bottom serration contact area. Therefore, there exists the need of a reaction washer stack including a helical ramp functionality that may have an overall stack height that fits within eventual predetermined height limits for washers and at the same time provides an initial bottom serration contact area that is at a minimum and at a maximum distance from the reaction washer axis and a final bottom serration contact area that extends radially substantially further inward towards the washer axis than the initial bottom serration contact area. The present invention addresses also this need. 
     SUMMARY 
     A reaction washer has a Belleville spring body with radial serrations on its shallow conical bottom and top faces. A narrow central serration free rim on washer top and bottom may prevent stress spikes in the serration grooves along the central washer hole during collapsing of the reaction washer at full load. 
     During initial loading, a minimum serration contact ring along the washer bottom circumference is in contact with the base surface in a maximum distance to the washer axis. Inadvertent eventual increased friction in the tread interface as well as eventual friction reducing elements on the base surface such as paint, dust or lubricant are thereby counter acted and slippage between the reaction washer and the base surface is prevented. 
     The small initial serration contact area causes also a biting of the bottom serrations at an earliest moment of load increase during tightening phase thereby transitioning earliest on from a pure friction-based contact to a biting contact. As the tightening load increases, the reaction washer continues to collapse and the bottom serrations extend their bite into the base surface towards the washer axis and within the radial extension of the nut or bolt head contact area with the washer top. At a maximum tightening load, the reaction washer is substantially flattened out and eventual top serrations of the reaction washer bite into the nut or bolt head and assist together with Belleville springily washer resistance in withholding it against becoming inadvertently loose. 
     A number of torque receiving structures are radially outward protruding arrayed along an outer circumference of the reaction washer and with their top substantially flush with the circumference of the conical serration top face. Their bottom is vertically offset from the conical serration bottom face to provide sufficient clearance to a base surface the reaction washer may be biting into while transferring a tightening load from an above nut or bolt head. During collapse of the reaction washer, the reaction washer experiences toroidal deformation causing the torque receiving structures to tilt upwards of about the angle about which a radial washer cross section collapses when flattening out. Torque receiving faces of the torque receiving structures are substantially radially oriented such that the angular deflection of the torque receive structures leaves their orientation substantially unaffected. Consequently, the contact with a drain interface of a reaction socket remains snug during deformation of the reaction socket between relaxed and flattened state and free of peak surface stresses. 
     As another favorable result of the substantially radially oriented torque receive faces, the reaction torque transfer from the torque transfer flanks of the drain interface onto the torque receiving faces is substantially free of radially acting forces, which in turn eliminates the need for a circumferentially continuous support around the drain interface. The torque inducing structures that provide the torque transfer flanks are consequently tapering downwards on their outside resulting in a wedge shape of them. This further reduces radial access space necessary to transfer the reaction torque onto the reaction washer and clears out eventual debris or paint that may cover the gaps between torque receiving structures. The radially outward open gaps between the torque inducing structures provide for an outward ejection of the debris while the reaction socket is pushed down over the reaction torque receiving interface of the reaction washer. 
     In a stacked dual washer configuration of the reaction washer, a top washer features on its bottom side a downward facing first multi ramp cone matched by a second upward facing multi ramp cone on the top said of a bottom washer. The conical multi ramp interface provides for a low height of the overall stack while at the same time providing the well-known functionality of a lock washer stack. A serration top face on the top washer has preferably the same Belleville angle than the serration bottom face on the bottom washer such that both top and bottom washer flatten out simultaneously. The toroidal deformation experienced by both top and bottom washers is synchronized across the conical ramp interface. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a first perspective cut down view of a first embodiment reaction washer that is supporting a nut above and that is resting on a base. 
       Also shown is a bottom portion of a reaction socket circumferentially engaging with the reaction washer. 
         FIG. 2  is the first perspective cut down view of the reaction washer and reaction socket of  FIG. 1 . 
         FIG. 3  is a second perspective cut up view of the reaction washer and reaction socket of  FIG. 1 . 
         FIG. 4  is the first perspective cut down view of the reaction washer and base of  FIG. 1 . 
         FIG. 5  is the second perspective cut up view of the reaction washer of  FIG. 1 . 
         FIG. 6  is the first perspective cut down view of a second embodiment reaction washer stack that is supporting a nut above and that is resting on a base. Also shown is a bottom portion of a reaction socket circumferentially engaging with a bottom washer of the reaction washer stack. 
         FIG. 7  is the first perspective cut down view of the reaction washer and base of  FIG. 6 . 
         FIG. 8  is a third perspective exploded down view of the reaction washer of  FIG. 6 . 
         FIG. 9  is a fourth perspective exploded down view of the reaction washer of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-5 , a reaction washer  10  of a first embodiment of the invention has a washer axis  10 A, a conical top face  13 , a conical bottom face  17  and a reaction torque receiving interface  23 . The washer axis  10 A may coincide with a reaction torque axis  100 A around which a reaction torque RT may be transferred onto the reaction torque receiving interface  23  via a drain interface  132  of a reaction socket  130 . The reaction torque RT may result from applying an oppositely acting actuation torque TL/TT as a tightening torque TT or a loosening torque TL on an actuation receiving structure  1  such as a nut or bolt head  1 . An actuation torque TT/TL may be applied by a well know torque wrench via a well-known actuation socket coupled to the actuation receiving structure  1 . Due to the thread pitch of the tightening thread  2 , the tightening torque TT may result during tightening in a rotation of the actuation receiving structure  1  and a sliding of the tightening thread  2  in a downward direction and increase from an initial load LI towards final tightening load LF onto base surface  7 . During loosening, the loosening torque TL may result of a sliding of the tightening thread  2  in loosening direction and the final tightening load LF being reduced again. 
     Loads LI and LF in between initial and final state are transferred via a load inducing face  3  at the bottom of the actuation receiving structure  2  onto a conical top face  13  of a reaction washer  10  or in case of the second embodiment of a top washer  55 . Top serrations  16  may be circumferentially arrayed on the conical top face  13  and a central serration free top rim  15  may be employed concentrically inside the conical top face  13 . In this case and due to a top Belleville angle  13 A, the central serration free top rim  15  may be slightly higher than the top serrations  16  such that during load transfer of a minimal load LI, the preferably planar load inducing face  3  may be resting on and sliding around the central serration free top rim  15  in an initial low resistance sliding contact. 
     During torque wrench tightening with actuation socket and reaction socket  130 , rotational resistance between the actuation receiving structure  1  and the reaction washer  10  or top washer  55  is of no substantial functional concern. During initial manual assembly and preloading up to the initial load LI to the contrary, rotational resistance between the actuation receiving structure  1  and the reaction washer  10  or top washer  55  may be of concern. Sliding of the bottom serrations  17  along the base surface  7  may cause material removal from the base surface  7  that may clog the bottom serrations  17  and impair their biting during the following torque wrench assisted tightening. Hence, the initial low resistance sliding contact may be favorably utilized during manual assembly of reaction washer  10  or reaction washer stack  55 ,  75  and actuation receiving structure  1  and eventual manual establishment of the initial load LI without need to manually hold the reaction washer  10  or reaction washer stack  55 ,  75  against inadvertent rotation and inadvertent clogging of the bottom serrations  17 . 
     Also referring to  FIG. 6  and once the actuation receiving structure  1 , the reaction washer  10  or reaction washer stack  55 ,  75  are assembled with washer holes  11 / 56 ,  76  being concentrically with respect to washer axis  10 A and torque transfer axis  100 A aligned with the base hole  8  and the tightening thread  2 , the conical top face  13  or central serration free top rim  15  may be loaded by the load inducing face  3 . A reaction socket  130  may be coupled via its drain interface  132  with a reaction torque receiving interface  23  of the reaction washer  10  or reaction washer stack  55 ,  75  and an actuation socket coupled with the actuation receiving structure  1 . For clarity, omitted are well known actuation socket and thread bolt against which the actuation receiving structure  1  in the depicted example of a nut  1  may be screwed on as is well known in the art. 
     The conical top face  13  may have a number of top serrations  16  that are circumferentially arrayed around the washer axis  10 A. The conical bottom face  17  features a number of bottom serrations  20  that are also circumferentially arrayed around the washer axis  10 A and that are radially inward extending from a bottom conical face circumference  18 . The reaction torque receiving interface  23  has a number of torque receive structures  25  that are radially outward protruding and circumferentially arrayed around the washer axis  10 A along an outer circumference of the reaction washer  10  and bottom washer  75 . 
     The reaction washer  10  may have a cross section thickness  10 H that is substantially continuous in radial direction at least in between the conical top face  13  and conical bottom face  17 . A top Belleville angle  13 A of the top conical face  13  and a bottom Belleville angel  17 A of the bottom conical face  17  are generally in between 0.1 and 8 degrees such that upon an initial load received via load inducing face  3  on at least one of the conical top face  13  and a top central serration free rim  15 , substantially only an initial peripheral serration contact rim  21  of the bottom serrations  20  penetrates into a base surface  6 . Preferably, the Belleville angles  13 A,  17 A are in between 2 and 5 deg. The base surface  6  is part of a base  5  and is underneath the reaction washer  10  and opposing the initial load LI. Upon increasing the initial load LI up to a final tightening load LF, the conical bottom face  17  is flattening out and the bottom serrations  20  are radially inward penetrating the base surface  6  up to a full load serration contact area  22 . 
     The torque receive structures  25  may be part of an actuation flange  35  positioned along a peripheral circumference of the reaction washer  10 . The actuation flange  35  may have a flange top  39  and a flange bottom  40 . The flange top  39  may be substantially level with and adjacent to a first conical top face circumference  14 . The flange bottom  40  is recessed from and adjacent to a second conical bottom face circumference  18 . The torque receive structures  25  may be extending in between the flange top  39  and flange bottom  40 . The torque receive structures  25  have torque receive faces  29  that are substantially radially inward oriented and aligned with the washer axis  10 A such that a reaction torque RT around the washer axis  10 A received by the torque receive faces  29  results in a contact force FC that is substantially free of any radial force component. 
     Part of a reaction torque drain system  100  and while the torque receiving interface  23  is coupled to a drain interface  132  of a reaction socket  130 , the torque receive faces  29  are oppositely substantially mating a number of torque transfer flanks  137  provided by torque inducing structures  135  that are circumferentially arrayed around a bottom flange  149  of a reaction socket  130 . Since the contact force FC is substantially in circumferential direction and free of any radial force component, the torque inducing structures  135  of the drain interface  132  may extend individually downward from the bottom flange  149  without need of any circumferentially continuous support structure. Moreover, the torque inducing structures  135  may have outer faces  139  that are conically downward and radially inward tapered in direction away from the reaction socket  130 . As a favorable result, the drain interface  132  may be fitted with tight spaces around the reaction washer  10 . As another favorable result, the drain interface  132  may with the downward wedge-shaped torque inducing structures  135  may easily penetrate into eventual thick debris layers around the torque receiving interface  23  and in between the torque receive structures  25  and may be radially self-cleaning as debris may radially outward eject from in between the torque inducing structures  135 . Such debris may be present particularly when having to access a reaction torque receiving interface  23  that has been painted over or otherwise exposed to environmentally induced debris deposits. 
     The torque receive structures  25  are preferably offset from the conical bottom face  25  such that a hooking nose  141  extending from a distal end of the torque transfer flanks  137  is hooking in underneath the respective torque receive structures  25  immediately above and clear off the base surface  7  while the drain interface  132  is coupled and reaction torque RT transferring to the reaction torque receiving interface  23 . The hooking noses  141  may be extending from both transfer flanks  137  of the torque inducing structures  135  so that they may hook underneath the torque receive structures  25  during application of a tightening torque TT or a loosening torque TL on the actuation receiving structure  1 . 
     The reaction washer  10  may further feature on its washer top  12  a central serration free top rim  15  and on its washer bottom  24  a central serration free bottom rim  19 . Central serration free top and bottom rims  15 ,  19  may provide for continuous stress levels that may be at a maximum around the washer hole  11  while the reaction washer  10  is flattened out and may eliminate peak stress areas in the grooves between the serrations  16 ,  20  along the most stress sensitive areas around the washer holes  11 ,  56 ,  76 . 
     Referring to  FIGS. 6-9  and a second embodiment of the invention, the reaction washer  55 ,  75  may be configured as reaction washer stack  55 ,  75  including a top washer  55  and a bottom washer  75 . The top washer  55  provides thereby the conical top face  13  with preferably the top serrations  16 , whereas the bottom washer  75  provides the conical bottom face  17  with the bottom serrations  20 . A conical multi ramp interface  58  in between the top and bottom washers  55 ,  75  is provided by a first multi ramp cone  59  on the bottom of the top washer  55  and a second multi ramp cone  79  on the top of the bottom washer  75 . The first multi ramp cone has a number of conical ramp faces  64  that are circumferentially arrayed and interposed by first ramp face steps  69  around the washer axis  10 A such that a cross section of the top washer  55  is outwards declining from an inner maximum top washer cross section thickness  55 CI towards an out outer top washer circumference  57 . There, the top washer  55  has a minimum top washer cross section height  55 CO. 
     The bottom washer  75  provides the reaction torque receiving interface  23 , preferably with the actuation flange  35  and torque receiving structures  25 . The bottom washer  75  features also the conical bottom face  17  with the circumferentially arrayed bottom serrations  20  that are radially inward extending from the bottom conical face circumference  18 . On the top of the bottom washer  75  is a second multi ramp cone  79  that is oppositely mating with its circumferentially arrayed second conical ramp faces  84  interposed by second ramp face steps  89  the first multi ramp cone  59  such that a cross section of the bottom washer  75  is outwards inclining from an inner bottom washer cross section thickness  75 CI towards the reaction torque receive interface. In that way, the first multi ramp cone  59  is snug contacting and rotationally blocked by the second multi ramp cone  79  in a thread tightening direction TT and is helically free sliding against the second multi ramp cone  79  in a thread loosening direction TL. The conical multi ramp interface  58  has an interface cone angle  58 A in radial direction relative to the washer axis  10 A that defines the proportion between respective inner and outer cross section thicknesses  55 CI- 55 CO,  75 CI- 75 CO. The ramp faces  64 ,  84  have an interface ramp angle  58 RA in circumferential direction around the washer axis  10 A that defines the pitch of the conical multi ramp interface  58 . The interface ramp angle  58 RA is larger than the well-known thread pitch of the tightening thread  2  such that during inadvertent rotation of the actuation receiving structure  1  in loosening direction around the washer axis  10 A, the top washer  55  may be dragged along via its top serrations  16  biting into the load inducing face  3  and the top washer  55  may ramp up against the bottom washer  75  more than the actuation receiving structure  1  may axially displace away from the base surface  7 . 
     Reaction washer  10  and top and bottom washer  55 ,  75  may be made of well-known materials such as hardened steel suitable of providing sufficient hardness for the serrations  16 ,  20  to bite into common materials of actuation receiving structures  1  and bases  6  while at the same time providing sufficient resilience for the Belleville spring action of them. A reaction washer  10  or reaction washer stack  55 ,  75  may be positioned with its hole  11 /( 56 ,  76 ) over a base hole  8  on a base surface  7 . Then the actuation receiving structure  1  such as a nut or bolt may be manually screwed on until the load inducing face  3  is in snug contact with either the conical top face  13  or the central serration free top rim  15  and an initial load LI is established without the reaction washer  10  or washer stack  55 ,  75  sliding with their bottom serrations  20  in general and the initial peripheral serration contact rim  21  in particular on the base surface  7 . During initial loading LI, the reaction washer  10  or reaction washer stack  55 ,  75  remains substantially in its natural shape without any flattening and the bottom serrations  20  in the bottom Belleville angle  17 A to the base surface  7  such that only their very outward end may contact the base surface  7  in a sharp point contact. All the sharp point contacts may circumferentially combine to the initial peripheral serration contact ring  21  that is in a maximum concentric distance around the washer axis  10  and has minimal contact area. Both of these criteria substantially contribute to a successful bite action of the bottom serrations  20  at initial load LI even across lubricant, or paint layers present on the base surface  7 . 
     In a following step, a well-known torque wrench is coupled to the actuation receiving structure  1  via an actuation socket to induce rotation and is coupled with its housing to the reaction torque receiving interface  23  via the reaction socket  130  to transfer and drain reaction torque RT. While a tightening torque TT is applied to the actuation receiving structure  1  and it being screwed downward along the tightening thread  2 , the bottom serrations  20  free of debris bite unimpeded into the base surface  7  and drain the corresponding reaction torque RT received via the reaction torque receiving interface  23  into the base  6 . 
     As the initial load LI ramps up to the final tightening load LF, the reaction washer  10  or reaction washer stack  55 ,  75  flattens out and the bottom serrations  20  gradually bite radially inward towards the washer axis  10 A and directly underneath the load inducing face  3  for a straight axial transfer of the full tightening load LF onto the bottom serrations  20  resulting in maximum bite action and rotational resistance of the reaction washer  10  or reaction washer stack  55 ,  75 . Any eventual lubricant or paint layers are thereby also gradually squeezed into the base hole  8  thereby maximizing bite of the bottom serrations  20  even in the eventual presence of lubricant or paint on the base surface  7 . 
     The flattening of the reaction washer  10  or reaction washer stack  55 ,  75  introduces an angular displacement of the torque receive structures  25 . Due to the preferably substantially radial alignment of the torque receive faces  29 , the snug contact with torque transfer flanks  137  is maintained and thus surface peak stresses and destructive deformation and galling prevented during washer flattening. In case of the reaction washer stack  55 ,  75 , the flattening of the top washer  55 ,  75  happens simultaneously and full functionality of the above described initial peripheral serration contact ring  21  is provided. Top and bottom Belleville angles  13 A and  17 A are preferably equal in particular in case of the second embodiment such that full load serration contact area  22  is provided while at the same time snug contact in the conical multi ramp interface  58  is maintained up to full load LF. 
     At full predetermined load LF, the eventual top serrations  16  bite into the load inducing face  3  such that the actuation receiving structure  1  is withheld by the reaction washer  10  or reaction washer stack  55 ,  75  against inadvertent rotation in loosening direction. At the same time, the Belleville resilient load carrying of the reaction washer  10  or reaction washer stack  55 ,  75 , the actuation receiving structure  1  is prevented from axially disengaging from the top serrations  16  in case of severe axial load vibrations as are well known in the art. In case of the reaction washer stack  55 ,  75  additional safety against inadvertent loosening of the actuation receiving structure  1  is provided by the conical multi ramp interface  58  while at the same time providing the reaction washer stack  55 ,  75  within a height that is similar to that of the reaction washer  10 . 
     To loosen the actuation receiving structure  1  again, the drain interface  132  may be reengaged with reaction torque receiving interface  23 . Any debris accumulated around the reaction torque receiving interface  23  or in between the torque receive structures  25  is displaced by the wedge-shaped torque inducing structures  135  and radially outward ejected via the radially outward open gaps between them. Once reaction socket  130  and actuation socket are coupled a loosening torque TL is applied to a level such that the friction in the tightening thread  2  and between the load inducing face  3  and the conical top face  13  with its eventual biting top serrations  13  is overcome. In case of the reaction washer stack  55 ,  75 , the loosening torque TL may be brought to a level such that the first conical ramp faces  64  fully slide around their respective second conical ramp faces  84  and plunge axially down over the ramp face steps  89  into the next following conical ramp face  84 , which may sufficiently stretch the thread bolt for it to become loose at that time. If not, then the actuation receiving structure  1  may be destructively removed in a well-known fashion. 
     Accordingly, the scope of the present invention described in the Figures and Specification above is set forth by the following claims and their legal equivalent: