Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
  • F16B13/04—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front
  • F16B13/06—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B19/00—Bolts without screw-thread; Pins, including deformable elements; Rivets
  • F16B19/04—Rivets; Spigots or the like fastened by riveting
  • F16B19/05—Bolts fastening by swaged-on collars
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
  • F16B13/00—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose
  • F16B13/04—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front
  • F16B13/06—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve
  • F16B13/063—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve by the use of an expander
  • F16B13/065—Dowels or other devices fastened in walls or the like by inserting them in holes made therein for that purpose with parts gripping in the hole or behind the reverse side of the wall after inserting from the front combined with expanding sleeve by the use of an expander fastened by extracting the screw, nail or the like

Definitions

• the present invention relates to anchor bolts to be set in concrete or the like.
• the present invention generally relates to two-piece swage type fasteners or lockbolts of the type illustrated in ⁇ . S. Patent Nos. 3,915,053, 2,531,048 and 4,472,096.
• Bolts for anchoring workpieces to concrete frequently utilize a mandrel and an expansion sleeve, with the sleeve being expanded in response to relative movement by the mandrel resulting in an expansion type interference fit with a pre-drilled bore in the concrete.
• the latter is accomplished by a relative axial force applied between the pin and sleeve.
• the blind head type connection between the expanded portion of the sleeve and the concrete bore could be compromised.
• the mandrel could move to such an extent relative to the sleeve that its final position would be unpredictable; in extreme cases the mandrel could move excessively to a position substan ⁇ tially through the sleeve.
• the present invention provides an anchor bolt for fastening a workpiece to a structure of concrete or the like by a relative axial force applied by a pull tool to the anchor bolt when positioned within a fastening bore in the structure, said anchor bolt comprising a tubular expansion sleeve having a through bore, a pin including a shank, a pull portion on said pin shank, a lock portion on said pin shank having a plurality of circumferentially extending lock grooves, a breakneck groove defining the weakest portion of said pin shank and located between said pull portion and said lock portion, a shank portion located adjacent said lock portion and being of a diameter to be received within said sleeve bore, a sleeve expansion section located at the opposite end of said shank portion, a tubular collar adapted to be located on said pin shank and to be swaged into said lock grooves in response to a first preselected magnitude of said relative axial force, said sleeve expansion section adapted to be moved axial
• sleeve expansion has been provided by an enlarged expansion portion of a mandrel being drawn into the sleeve.
• the pin is provided with an extended expansion section which will expand the associated ' portion of the sleeve radially outwardly to provide a first level of expansion grip or lock between the sleeve and the concrete bore.
• the expansion section of the pin terminates in an enlarged pin head having a flat or planar surface which is adapted to engage the expanded end of the sleeve.
• this engagement acts as a positive stop between the pin and sleeve to locate the pin at a desired position relative to the opposite end of the sleeve.
• the engagement of the enlarged pin head can provide further radial expansion of the inner end of the sleeve either by radially outward bulbing as in a column type buckling or by radial sleeve expansion if the head moves into the sleeve end.
• additional sleeve expansion and a second level of expansion grip will be provided by the pin head to enhance the lock between the sleeve and concrete bore. Even in this latter event, the additional movement of " the pin can be relatively minor with the result that the final location of the pin will be within a predictable, acceptable range.
• the expandable end of the sleeve may be serrated or roughened to enhance the biting or frictional engagement with the walls of the concrete bore.
• a flanged collar may be used to provide an enlarged reaction bearing surface against the concrete'or workpiece outer surface.
• a relatively straight collar is used with a flat washer to provide the reaction or bearing surface against the concrete or workpiece outer surface.
• the lock grooves of the pin are in the form of a helical male thread.
• the collar is provided with a mating, female thread of a preselected limited extent such that a pre-assembly of the sleeve, pin and collar can be accommodated.
• the strength of the female collar thread is selected such that, in response to the relative axial setting force, at a level prior to the initiation of collar deformation or swaging into the lock grooves of the pin, it will shear or deform such that the collar will now be free to respond to the installation loads in the same manner as a collar without such limited female thread form.
• the lock grooves may be constructed to be of a unique configura ⁇ tion having the desired high strength to resist distortion.
• the lock grooves in the pin are very shallow and are constructed to have roots of a simulated streamlined shape. While the lock grooves define a desired thread configuration, the shallow and simulated streamlined shape provide a resultant tensile strength, resistance to deformation during collar swage and fatigue life which is superior to that of comparable threaded fasteners or prior lock groove constructions.
• the collar is constructed to have a predeter- mined wall thickness, and hence volume, not only to provide an over fill condition of the lock grooves during swaging to assure a good fill of the lock grooves but also to provide sufficient hoop stiffness to inhibit spring back of the collar material out of the shallow lock grooves in the pin.
• the latter retained clamp between the pin, sleeve and collar having a magnitude which is a high percentage of the installation load and of the yield strength of the pin in tension across the lock grooves.
• the resultant preload on the pin is slightly below that at which yielding would occur in the helical lock grooves of the pin.
• the collar is longer than that required to provide engagement of the appropriate number of pin and collar shoulders to hold that preload; in this case fail- ure of the fastener under tensile loading will occur diametrically across the pin lock grooves.
• the magnitude of the latter tensile loading will be equal to (and preferably greater) than the ultimate design tensile load for the fastened joint such that failure will occur in the concrete or across the lock grooves. It is advantageous that the pin be of a high strength construction such that there will be no signi ⁇ ficant yielding in response to the swage load.
• Figure 1 is an elevational view with some parts shown in section of an anchor bolt of the present invention in a concrete bore prior to being set by an installation tool;
• Figure 2 is a view, similar to Figure 1 depicting the anchor bolt after it has been partially set with an end portion of the sleeve radially expanded against the concrete bore surface;
• Figure 3 is a view similar to Figures 1 and 2 depicting the anchor bolt after the pin head has engaged the expanded end of the sleeve and the collar has been swaged onto the pin;
• Figure 4 is a view similar to that of Figure 1 showing a modified form of anchor bolt;
• Figure 5 is a fragmentary view similar to Figure 1 of an anchor bolt having high strength helical lock grooves of a shallow configuration and embodying features of the present invention.
• Figure 6 is a fragmentary sectional view to enlarged scale of a preferred form of the helical lock groove for the pin of the anchor bolt of Figure 5.
• an anchor bolt 10 is shown located in a pre-drilled bore 12 in a concrete member 14 prior to being set to secure a workpiece 16 to the outer surface 18 of the concrete member 14.
• the workpiece 16 has a bore 20 adapted to be aligned with concrete bore 12.
• the anchor bolt 10 has a pin or mandrel 22 having an elongated shank 24 terminating at one end in an enlarged head 26.
• the pin shank 24 has a straight shank section 28 of a uniform diameter adjacent the head 26 followed by an expansion, tapered portion 30.
• the tapered portion 30 connects the straight shank section 28 with a straight, reduced diameter shank section 32 of a uniform diameter wnich in turn is followed by a lock portion 34 comprised of a plurality of helical lock grooves 36.
• a pull portion 38 comprised of a plurality of annular pull grooves 40 terminates the opposite end of pin shank 24 and an annular breakneck groove 42 defines the weakest portion of the pin shank 24 and is located between the pull portion 38 and the lock portion 34.
• the anchor bolt 10 also includes an elongated, tubular sleeve 44 of a generally uniform cross section throughout its length.
• the sleeve 44 has a central bore 45 which is in a close clearance fit with the reduced diameter pin shank section 32.
• the maximum diameter of the lock portion 34 is no greater than around that of the reduced pin shank section 32 while the pull groove portion 38 can be of a smaller maximum diameter than reduced shank section 32.
• the sleeve 44 can be freely assembled onto the pin shank 24 down to the tapered portion 30 and can be lightly staked or othersie secured to the pin 22 such that the pin 22 and sleeve 44 can be handled as an assembly.
• the sleeve 44 being of a uniform cross section, can be assembled from either end onto the pin shank 24.
• a tubular locking collar 46 is adapted to be located over the portion of pin shank 24 protruding from the outer end of workpiece bore 20.
• Collar 46 has a relatively straight shank portion 48 and an enlarged flange 50 adapted to overengage the confronting or outer end of sleeve 44 and the workpiece bore 20 such that it partially engages the surrounding portion of outer surface 52 of the workpiece 16.
• the collar 46 is adapted to be swaged into the helical locking grooves 36 to lock the pin 22 and sleeve 44 together after the anchor bolt 20 has been set by a relative axial force applied between the pin 22 and collar 46 via a pull tool 54.
• the pull tool 54 can be of a conventional structure well known in the art and hence is only partially shown for illustration purposes.
• the collar 46 can be pre-assembled to the pin 22 whereby the pin 22, the sleeve 44 and the collar 46 will be held together as an assembly.
• the collar 46 can be provided with a partial mating thread 62.
• This construction will facilitate pre- assembly of the pin 22, sleeve 44 and collar 46.
• the noted fastener components can be pre-assembled by threading the collar 46 onto the threaded lock portion 34 of the pin 22.
• the collar flange 50 can be provided with a conventional hex head or other irregular configuration to permit gripping by a suitable tool.
• the pull portion 38 of the pin 22 can be provided with flats for gripping to prevent relative rotation during the threaded pre-assembly.
• ⁇ the end of the pin shank 24 can be provided with an Allen head type opening to assist in preventing relative rotation during pre-assembly.
• the flange 50 could be annular.
• the concrete bore 12 is drilled to a depth sufficient to accept the assembly of the pin 22, sleeve 44 and collar 46 such that with the workpiece 16 in place, the sleeve 44 will not extend above the surface 52 of the workpiece 16. At the same time a sufficient number of the pull grooves 40 will extend beyond the workpiece surface 52 to facilitate gripping by a gripping jaw assembly 56 of tool 54.
• the pre-assembled fastener 10 including the pin 22, sleeve 44, and collar 46 is positioned in the concrete bore 12 and workpiece bore 20 with the collar flange 50 engaging the workpiece surface 52.
• the pull tool 54 is applied to the fastener 10 with the jaw assembly 56 gripping the pull grooves 40 and a swage anvil 58 engaging the outer end of the collar 46.
• a rela ⁇ tive axial force is applied between the pin 22 and collar 46.
• the pin 22 moves the expansion tapered portion 30 of the pin shank 24 into sleeve bore 45 causing the inner end of the sleeve 44 to expand radially outwardly to engage the confronting surface of the concrete bore 12.
• the tapered portion 30 moves further into the sleeve bore
• the inner end of sleeve 44 is expanded to overengage of the enlarged smooth shank section 28 of the pin 22.
• the sleeve expansion continues as noted until the enlarged pin head 26 engages the expanded end of the sleeve 44; this defines the first level of expansion grip or lock between the sleeve 44 and concrete bore 12.
• the engagement of the pin head 26 with the expanded end of the sleeve 44 acts as a pin stop to inhibit f rther pin travel and also confines .the end of the sleeve 44 and inhibits it from extruding past the pin head 26.
• the relative axial setting force can attain a magnitude such that the anvil 58 of the tool 54 will swage the collar 46 into the locking grooves 36 which are now in a desired alignment with the collar 46.
• a further increase in relative axial force results in the pin shank 24 being severed at the breakneck groove 42. This completes the installation resulting in a set joint generally as shown in Figure 3.
• the collar thread 62 is limited in number and radial depth, and hence strength, such that when the installation sequence is commenced the collar thread 62 will readily deform or shear as the pin 22 is moved axially relative to the collar 46; this will occur at a relatively low axial load such that premature swaging of the collar 46 into the pin lock grooves 36 will not occur.
• a single collar thread 62 of around a 360° circumferential extent was adequate for pre-assembly purposes while still being readily deformable during installation.
• the pull groove portion 38 has a maximum diameter less than the inside diameter of the collar thread 62 whereby the collar 46 can be readily moved onto the pin 22 and the collar thread 62 engaged with the helical lock groove portion 34.
• the clearance between the concrete bore 12 and the outer surface of sleeve 44 will be such as to have a preselected magnitude to facilitate reception of the assembly of pin 22 and sleeve 44 in the bore 12 but still being of a restricted clearance such that, upon expansion of the inner end of sleeve 44, a secure lock between the sleeve and the concrete bore 12 will be attained.
• the enlarged pin head 26 is of a diameter generally equal to the outside diameter of the inner end of sleeve 44.
• the adjacent straight shank portion 28 has a diameter which is generally equal to the mean diameter of the sleeve 44 i.e.
• the pin shank 24 had its reduced diameter shank section 32 with a diameter of around 1.143 cm (.450 inches) and the enlarged diameter shank section 28 with a diameter of 1.435 cm (.565 inches).
• the enlarged pin head 26 had a diameter of around 1.587 cm (.625 inches).
• the axial length of the enlarged diameter shank section 28 was within a range of approx ⁇ imately around two to three times the length of the tapered expansion pin portion 30.
• the tapered portion 30 extended at an angle of around 15° with the axis of the pin 22.
• the enlarged shank section 28 had an axial length of 1.955 cm (.770 inches) while the tapered portion 30 had an axial length of 0.838 cm (.330 inches).
• the total diametrical clear ⁇ ance between the outside diameter of the sleeve 44 and the concrete bore 12 was between .0254 cm (.010 inches) and .101 cm (.040 inches) .
• the lock formed upon final expansion of the sleeve 44 as the pin head 26 engages the expanded end of sleeve 44 will provide a desired, first level lock between the set fastener 10 and the concrete bore 12 to securely hold the workpiece 16 to the concrete member 14.
• the clearance between concrete bore 12 and the sleeve 44 may be larger than desired.
• the concrete bore 12 in the area of sleeve expansion may have excessive local pulverization.
• the adequacy of the lock at the first level of radial expansion may be impaired. With the present construction, however, such variations can be reasonably accommodated while still providing an adquate lock at the second level of expansion.
• the pin head 26 engages the inner, expanded end of the sleeve 44, if the expanded end of sleeve 44 has not tightly engaged the wall of the concrete bore 12 it will still be capable of further radial expansion. In this case the pin head 26 can cause the sleeve end to bulb radially outwardly as in a column buckling type situation or the pin head 26 can move axially into the inner diameter 45 of the sleeve 44.
• the engaging end surface 60 of the pin head 26 is generally .transverse or in quadrature to the pin axis; this will provide for a planar surface of engagement against the inner end of sleeve 44.
• the pin head 26 can move into the sleeve 44 generally without deformation to the pin head 26.
• the engaging surface 60 of the pin head 26 may shear a ring of material from the inner end of sleeve 44 facilitating its entry into the bore 45 and also facilitating radial expansion of the sleeve 44.
• the result is an increase in radial expansion of the sleeve 44 whereby the noted situations can be accommodated to provide a secure lock between the set fastener 10 and the concrete bore 12.
• the pin 22 was constructed of AISI 4140 Alloy Steel having a hardness of Re 33-36 while the sleeve 44 was constructed of AISI 1020 Carbon Steel having a hardness of Rb 80-90.
• the contour of the engaging surface of the collar 46 relative to that of the swage anvil 58 is constructed such that swaging of the collar 46 into the lock grooves 36 will not occur until the above described setting sequence has been completed i.e. collar " swage will be held off until the blind head 59 has been finally formed and, where required, the second level of increased radial expansion via the pin head 26 has occurred.
• the threaded lock section 34 in one form of the invention has an axial length such that upon completion of installation a substantial portion extends beyond the outer end of the collar 46, see Figure 3. This facilitates attachment of additional structures to the fastener assembly 10 with a threaded connection via a suitably threaded member.
• the installed fastener 10 should sustain that design load without significant movement out from the concrete bore 12.
• the extra threaded portion extending beyond the end of collar 46 facilitates the application of a test tool to the pin 22 whereby the proof test can be conducted.
• FIG. 4 Another form of the invention is shown in Figure 4.
• components similar to like components in Figures 1-3 have been given the same numerical designation with the addition of the letter postscript "a” and hence a description of some of the components has been omitted for purposes of simplicity.
• anchor bolt 10a is located in a pre- drilled bore 12a in*a concrete member 14a for securing a workpiece 16a to the concrete member 14a.
• the pin or mandrel 22a is constructed substan ⁇ tially the same as pin 22 of Figures 1-3 except that the lock portion 34a is provided with one or more axially extending grooves 63 which act as an antirotation mechanism to prevent relative rotation between -collar 46a and pin 22a and hence inhibit removal of the collar 46a from the threaded lock grooves 36a after the fastener 10a has been set.
• the inner end of the sleeve 44a is provided with a section 64 having a roughened outer surface which can be in the form of a knurl or serrations.
• the roughened section 64 has an axial length at least equal to around the axial length of the smooth pin shank section 28a. Prefer ⁇ ably, the length of section 64 is greater such that upon installation, the roughened section 64 will at least partially overengage the tapered expansion pin portion 30a.
• the roughened surface of section 64 will tend to bite into the confronting surface- of concrete bore 12a to enhance the gripping action or lock between the sleeve 44a and concrete bore 12a.
• the collar 46a has generally straight sidewalls except for an enlarged hold-off bead 66 at its outer end.
• the hold-off bead 66 along with the contour of the engaging swage surface of the swage anvil (not shown) will provide the desired resistance or hold-off from initial swage until a desired magnitude of relative axial setting force is attained.
• the inner end of the collar 46a is of a generally straight tubular configuration.
• a flat washer 68 is located between the collar 46a and the outer end of the sleeve 44a and is adapted to engage the workpiece surface 52a to provide the fastener reaction surface for the installation loads.
• the washer 68 has a bore 70 which is generally of the diameter of sleeve bore 45a.
• the helical collar thread 62a in cooperation with the threaded lock groove portion 34a will hold the pin 22a, sleeve 44a, reaction washer 68 and collar 46a together in a pre-assembly to facilitate handling.
• anchor bolt 10a The general operation of the anchor bolt 10a is similar to that of anchor bolt 10 of Figures 1-3 and will not be repeated.
• a concrete joint fastened with the anchor bolt of the present invention have sufficient strength to accept a tensile load of a magnitude below a preselected ultimate load without failure either in the anchor bolt or in the surrounding concrete.
• an annular lock groove configuration could be employed utilizing certain of the features of the present invention, in many applications a thread form (as shown in Figures 1-4) , having the advantages discussed, is desirable.
• a conventional thread form has a configuration which, in some cases, could result in a failure at a tensile load lower than the desired ultimate design tensile load or even at the installation loads.
• a conventional thread form would be susceptible to deformation from collar swage whereby its capability to function as a threaded connection could be impaired.
• the lock grooves 36b of the lock groove portion 34b of pin 22b are of a shallow construction and have a closely approximated streamlined root configuration.
• a streamlined contour provides a transition between two different diameters with essentially no stress concentra ⁇ tion or an effective stress concentration factor (Kt) of one (1) .
• the helical lock grooves 36b, which are separated by annular crests or shoulders 78 can be considered to be defined by a root portion 72, which is connected at one end to a leading transition portion 74 and at the opposite end to a trailing transition portion 76.
• the root portion 72 is generally elliptically shaped and can be generally defined by the relationship: 2 L_ + y _ ⁇
• P is the pitch between successive helical lock grooves 36b;
• P/X is the width of the shoulders 70 where X is selected to provide proportioned strength between the ultimate shear strengths of the material of collar 46b and the material of pin 22b such that, under tensile load, a failure in shear could occur at the effective shear plane across either the pin shoulders 78 or the resultant shoulders in the swaged collar;
• h is the depth of helical lock grooves 36b;
• Dr is the effective root diameter of helical lock grooves 36b;
• Du is the crest diameter ⁇ f pin shoulers 78 (or the diameter defined by the crests of the threaded pin 22b) ;
• Da is the major axis of the ellipse defining the elliptical root contour of root portion 72;
• Db is the minor axis of the ellipse defining the elliptical root contour of root portion 72;
• Db/2 is one half of the minor axis or the distance along the minor axis
• L is the axial distance between the respective tangential intercepts of the leading transition portion 74 and the -trailing transition portion 76 with the ellipse portion defining root portion 72; and 10. W is the radial distance along the minor axis Db from root portion 72 to the axial line defined by the axial length L.
• the leading transition portion 74 was provided to be at a 40° angle with a plane transverse to the axis of pin 22b while the trailing transition portion 76 was provided to be at a steeper angle of 20°.
• the angle of the leading portion 74 facilitates flow of the material of collar 46b in swage while the steeper angled trailing portion 76 provides a buttressing effect relative to the swaged collar material. This buttressing effect facilitates clamping of the collar 46b and the sleeve 44b as the collar 46b elongates during swage.
• the transition portions 74 and 76 tangentially intercept the elliptical root portion 72 whereby a smooth transition in contour is provided.
• the elliptically shaped root portion 72 has an axial length L which is less . than the major diameter Da with a radial width W which is less than the minor axis dimension Db/2.
• the root portion 72 will always have a length L and width W no greater than the major and minor axes Da and Db, respectively. However, in order to assure a smooth transition with the essentially straight transition portions 74 and 76, generally at the angles of inclination noted, it is desirable that the width W be no less than around 80% of the minor axis dimension Db/2 or 40% of Db. With the fastener construction of Figures 5-6, it has been foun ' d that the depth of each of the grooves can be selected to provide a desired minimum ratio of depth h to the crest diameter Du of the pin 22b. In this regard, the major criteria of groove depth h is that it be sufficiently deep as a practical matter to receive and retain the material of the collar 48b after swage.
• a groove depth h of around 0.04 x Du or less is desirable
• the groove 36b being shallow will permit the use of the simulated stream ⁇ lined or elliptical shape at root portion 72 resulting in a significantly reduced stress concentration factor Kt. Again, the result will be an increase in fatigue life over a comparable conventional threaded fastener.
• the same comparison holds true with regard to a comparison with anchor lock grooves of the prior art (supra) .
• the volume of collar 46b was selected to provide 'overpacking' , i.e., a volume of collar 46b to provide substantially more volume of collar material for filling grooves 36b than they could normally accept within the swage envelope defined by the throat 80 of the swage cavity of anvil 58b and the confronting portion of the lock groove portion 34b of pin 22b.
• a volume of collar material which has an excess of at least around 16%. With the shallow helical grooves 36b, excess collar volume over the noted 16% is not required since the amount of radial inward movement of collar material is not as great as with prior lock grooves of a deeper construction.
• the percentage 'overfill' or 'overpacking' noted can be generally determined for a finite length of the effective swage portion of throat 80 (see Figures 5 and 6) by the relationship:
• Da is the diameter of the throat 80 of anvil 58b
• Dc is the outside diameter of the collar 46b before swage
• ID is the inside diameter of the collar 46b before swage
• Dm is the mean diameter of the lock grooves 36b; and dl is considered to be a finite length within the swage portion of throat 80.
• the pin 22b could be made of AISI 4140 alloy steel or AISI 1541 carbon steel having an ultimate shear strength of at least around 95 KSI.
• the collar 46b could be made of AISI 1035 (or AISI 1020) carbon steel having an ultimate shear strength of at least around 45 KSI.
• the pin 22b has an ultimate shear strength relative to that of collar 46b in the ratio in a range of around 1.8:1 to around 2.4:1.
• the pin 22b has a sufficient hardness to accept both the high tensile preloads desired and the swage loads on the collar substantially without yielding.
• the shallow grooves 36b are more easily formed than the prior, deeper lock grooves and, in fact, can be formed after the pin has been hardened.
• the collar 46b must have a sufficient wall thickness and, hence, volume to insure that enough collar material will move axially in elongation. At the same time it is desirable that the swaged collar have sufficient wall thickness and, hence, have sufficient strength to resist any significant spring back from the shallow lock grooves 36b.
• the collar wall also should have sufficient thickness to resist significant radial expansion under tensile load such that the pin shoulders 70 and collar shoulders remain in substantially full engagement as the design tensile load on the joint is reached. If the collar wall after swage does not provide sufficient radial stiffness, the collar 46b could expand radially under tensile load, reducing the effective shear plane carrying the load.
• the collar wall thickness is selected to provide the necessary material to promote swaging into the shallow helical lock grooves 36b and flow in elongation to provide the desired clamp load.
• the collar wall thickness at final swage is also selected to provide sufficient, radial stiffness or hoop strength to resist significant radial spring back from the grooves 36b both during initial swage and also under subsequent tensile loading.
• the volume of the collar 46b and swage cavity 80 are selected to provide movement of the material of collar 46b into the grooves 36b to assure a good fill.
• the width of the helical pin grooves 36b and pin shoulders 78 and the complementary grooves and shoulders of the swaged collar 46b be proportioned in width relative to the respective shear strengths of the materials of pin 22b and collar 46b such that both the shoulders defined by pin grooves 36b of the pin 22b and the shoulders defined by interlocking grooves of the swaged collar 46b are in incipient or simultaneous failure in shear at or above the preselected minimum ultimate design tensile load on the fastened joint. It is preferred that the design provide for the shoulders defined by the grooves of collar 46b to fail prior to the shoulders defined by pin lock grooves 36b, i.e.
• the shoulders 78 of pin lock grooves 36b would fail in shear at approximately 110% of the tensile load at which the shoulders of swaged collar 46b would fail.
• proportioning the grooves as noted, the engaged length of pin and collar can be minimized for a given tensile load.
• the application of proportioned strength permits the pin grooves 36b to be elongated relative to the shoulders 78 whereby the use of an approximated, stream ⁇ lined root shape can be more effectively employed.
• the shallow groove structure permits smooth transitions between the root 72 and the connecting side- walls 74 and 76. While the elliptical contour employed will closely approximate the desired streamlined shape other similar continuous curves could be utilized.
• the swaged collar 46b With the fastener 10b installed, the swaged collar 46b will have a complementary female thread formed in its bore. This will now permit the collar 46b to be removed by torquing it off the pin 22b. At the same time the collar 46b could, in some circumstances, have additional torque applied.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Dowels (AREA)
• Joining Of Building Structures In Genera (AREA)

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Citations (2)

• 1986
  • 1986-04-24 EP EP86903029A patent/EP0221144A1/en not_active Withdrawn
  • 1986-04-24 AU AU58149/86A patent/AU579733B2/en not_active Ceased
  • 1986-04-24 JP JP61502486A patent/JPS63500196A/ja active Pending
  • 1986-04-24 WO PCT/US1986/000870 patent/WO1986006447A2/en not_active Application Discontinuation
  • 1986-04-28 ES ES1986296605U patent/ES296605Y/es not_active Expired
  • 1986-04-29 PT PT82478A patent/PT82478A/pt not_active Application Discontinuation
  • 1986-04-29 AR AR303797A patent/AR240191A1/es active
  • 1986-04-29 ZA ZA863199A patent/ZA863199B/xx unknown
  • 1986-04-29 IL IL78645A patent/IL78645A0/xx unknown
  • 1986-04-29 CN CN86102960.7A patent/CN1004722B/zh not_active Expired
  • 1986-04-29 IN IN336/CAL/86A patent/IN163030B/en unknown
  • 1986-12-29 KR KR860700950A patent/KR880700172A/ko not_active Application Discontinuation

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