WO1991005172A1 - Blind fastener with large bearing area - Google Patents
Blind fastener with large bearing area Download PDFInfo
- Publication number
- WO1991005172A1 WO1991005172A1 PCT/US1990/005161 US9005161W WO9105172A1 WO 1991005172 A1 WO1991005172 A1 WO 1991005172A1 US 9005161 W US9005161 W US 9005161W WO 9105172 A1 WO9105172 A1 WO 9105172A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- fastener
- sleeve section
- pin
- sleeve
- workpieces
- Prior art date
Links
- 239000000463 material Substances 0.000 claims abstract description 23
- 230000000007 visual effect Effects 0.000 claims abstract description 6
- 238000009434 installation Methods 0.000 claims description 20
- 230000004044 response Effects 0.000 claims description 11
- 239000010963 304 stainless steel Substances 0.000 claims description 3
- 229910000589 SAE 304 stainless steel Inorganic materials 0.000 claims description 3
- 229910001069 Ti alloy Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 2
- 229910001220 stainless steel Inorganic materials 0.000 claims description 2
- 230000002829 reductive effect Effects 0.000 abstract description 8
- 239000002131 composite material Substances 0.000 abstract description 7
- 235000019589 hardness Nutrition 0.000 description 22
- 238000010276 construction Methods 0.000 description 12
- 230000007704 transition Effects 0.000 description 7
- 241001136800 Anas acuta Species 0.000 description 4
- 238000005452 bending Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 230000002401 inhibitory effect Effects 0.000 description 2
- 230000013011 mating Effects 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000005482 strain hardening Methods 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000036961 partial effect Effects 0.000 description 1
- 230000036316 preload Effects 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 229920005992 thermoplastic resin Polymers 0.000 description 1
- 239000004634 thermosetting polymer Substances 0.000 description 1
- 238000011179 visual inspection Methods 0.000 description 1
Classifications
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- 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
- F16B19/08—Hollow rivets; Multi-part rivets
- F16B19/10—Hollow rivets; Multi-part rivets fastened by expanding mechanically
- F16B19/1027—Multi-part rivets
- F16B19/1036—Blind rivets
- F16B19/1045—Blind rivets fastened by a pull - mandrel or the like
- F16B19/1063—Blind rivets fastened by a pull - mandrel or the like with a sleeve or collar sliding over the hollow rivet body during the pulling operation
-
- 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
- F16B19/08—Hollow rivets; Multi-part rivets
- F16B19/10—Hollow rivets; Multi-part rivets fastened by expanding mechanically
Definitions
- the present invention relates to blind fasteners for securing workpieces of a crushable or composite material arid more particularly to a blind fastener providing a blind head with a large effective bearing surface on the blind side of such workpieces.
- a blind fastener providing a large bearing area under the blind head. The large bearing or surface area around the workpiece opening on the blind side assists in inhibiting localized crushing and flaking of the workpiece material engaged by the blind head.
- the preceding patents generally disclose a multipiece fastener including a main sleeve or nut member and an expandable sleeve which forms a blind head as it is axially moved by a pin member over the blind end of the main sleeve.
- the '900 patent to Villo generally shows this type of structure but the resultant fastener does not form a blind head ' having a large bearing area or "footprint".
- the , 222 patent to Wilson shows a structure including three expandable sleeves utilized in an effort to provide a blind head having a large bearing area.
- the '650 patent to Dahl et al and '652 patent to Pratt each show an expandable sleeve having a reduced section portion at the leading end which bulbs radially outwardly to ostensibly provide a large bearing area.
- a variation of these structures is shown in the '346 patent to Hall et al where the reduced section portion engages a shoulder on the pin member.
- the expandable sleeve has a primary section of one wall thickness or cross-section and a secondary section of reduced wall thickness or cross-section.
- the main sleeve or nut member has a tapered nose portion at its blind side.
- the expandable sleeve is radially expanded as it moves axially over the tapered nose portion via a relative axial pulling force applied between the pin member and the nut member.
- the blind head is formed by folding of the secondary section as it engages the workpiece surface.
- the softened, expandable sleeves do not consistently provide, if at all, a blind head having the desired large bearing area against the engaged workpiece surface. This is due to radial inward movement of the leading end of the primary sleeve section as it moves axially over the tapered nose portion of the main sleeve. It is believed that this deformation occurs in response to hoop stresses resulting from the initial radial expansion.
- a large blind side bearing area can be achieved by providing an expandable sleeve structure having its primary section to be of a higher hardness than the secondary section and thus to have a greater resistance to hoop stresses imposed during installation; as noted it is the hoop stresses present during installation which cause radial inward deformation of the softened sleeves of the prior art.
- the magnitude of the lower hardness of the secondary section will be selected to promote folding for formation of the blind head at the desired installation load; at the same time, the magnitude of the higher hardness of the primary section will be selected to inhibit radial inward deformation of that section resulting in the formation of the blind head with large bearing area by the secondary section.
- the fastener of the present invention is constructed to be set by a relative axial force applied between the pin on the one hand and the main sleeve and expandable sleeve on the other hand whereby the expandable sleeve is moved over the tapered blind end or nose portion of the main sleeve.
- the secondary sleeve section will be radially expanded first and moved axially until its free end engages the blind side of the workpieces.
- the secondary sleeve section is and remains integrally connected to the primary sleeve section; when the axial or column load attains a preselected magnitude the secondary sleeve section will fold to form a blind, bulbed head having a large effective bearing area whereby localized crushing of the engaged workpiece is inhibited.
- the relative axial load continues to increase until the pin fractures at a breakneck groove severing a pintail portion of the pin leaving a pin shank of a predetermined minimal length.
- the leading end of the primary sleeve section will be radially expanded as it moves axially over the tapered nose portion of the main sleeve.
- the higher hardness, and hence strength, of the primary section will resist and substantially preclude radial inward deformation of that section throughout the installation whereby the final formation of a blind head of desired large bearing area by the softer secondary sleeve section will be promoted.
- solution treated or softened sleeves the blind head in some conditions can be partially deflected away from the engaged workpiece surface by the radially inward movement of the primary sleeve section thereby reducing the effective size and integrity of the footprint of the blind head.
- Fasteners of the type of the present invention are provided in different diameters and in different lengths to accommodate workpieces varying in .thickness.
- the nominal total thickness of workpieces to be secured by a fastener of a given length is considered to be the "grip" of that fastener. It is desirable that a fastener of such given length or “grip” can be used to clamp or secure workpieces varying in total thickness over a predetermined range.
- the noted range is considered to be the "grip range" of the fastener.
- the desired large 'footprint' and hence large effective engaged area of the blind head can be provided by the fastener of a given; length (or grip) for joining workpieces varying in total thickness over a considerable grip range.
- the installed fastener provide an indication that the fastener with proper grip has been installed with workpieces within its grip range; the most effective means of indication of the use of a fastener of correct or incorrect grip is the final position of the pin.
- the buckling could be such that the axial travel of the pin would continue until the pin head engaged the nose or tapered end of the main sleeve or nut member.
- the operator or inspector on the open side of the workpieces by visual inspection, could erroneously conclude from the overtravel of the pin that a fastener with incorrect grip was used. In other circumstances the operator or inspector could fail to detect that the fastener was used in an incorrect grip.
- the total amount of pin travel is controlled since the primary section of the expandable sleeve will not buckle; thus, over the selected grip range of the fastener of a given grip, the pin break location will occur near the outer sheet line or surface of the outer workpiece with a maximum grip condition and at a determinable distance beyond the outer sheet line with a minimum grip condition. Any deviation from these extremes will indicate or flag an improper or undesirable grip condition for the set fastener. In this way, the present invention provides a visual and/or measurable indication that the fastener of proper grip has been used.
- Fasteners of this type are utilized to secure workpieces being predominantly subjected to shear loads rather than tensile loads.
- shear loads In a lap shear type joint, however, there is also a twisting or bending load being applied which has a tensile component.
- the magnitude of shear load capacity of such fasteners will be influenced by its ability to withstand the combination loading applied resulting from twisting and/or bending loads.
- the resultant larger footprint of the blind head plus the higher hardness of the primary sleeve portion and its general freedom from buckling provides a fastener construction having a greater resistance to the twisting or bending loads and hence provides a higher shear load capability than fasteners utilizing the softened construction.
- a blind fastener for fastening workpieces of a crushable or composite material and which provides a blind head having a large bearing area against the adjacent blind side of the workpieces. It is another object of the present invention to provide a blind fastener of the above described type having a'main sleeve and an expandable sleeve with the expandable sleeve having a secondary section of reduced cross-section which is of a lower hardness than the remainder or primary section of the expandable sleeve such that the secondary sleeve section can fold to form the blind head while the primary section can resist radial inward deformation at the axial loads necessary to set the fastener whereby the blind head will be formed with a desired large bearing area.
- Figure 1 is an elevational view with some parts shown in section of a fastener embodying features of the present invention and in assembly relationship with a pair of workpieces of maximum total thickness to be fastened together and including a main sleeve, an expandable sleeve and a pin member;
- Figure 2 is an end view of the assembly of Figure 1 taken in the direction of the arrow 2;
- Figure 3 is an elevational view with some parts shown in section of the fastener of Figure 1 after it has been set;
- Figure 4 is an enlarged fragmentary view of that portion of the fastener of Figure l in the area indicated by the arrow 4 depicting the transition area from the soft to hard sections of the expandable sleeve;
- Figure 5 is a view similar to that of Figure 3 depicting the fastener of Figures 1-4 after it has been set and fastening workpieces of a minimum total thickness;
- Figure 6 is a view similar to that of Figure 3 and depicting a fastener constructed in accordance with the prior art after it has been set and fastening workpieces of a maximum total thickness
- Figure 7 is a view similar to that of Figure 5 and depicting the prior art fastener of Figure 6 after it has been set and fastening workpieces of a minimum total thickness.
- a multipieced fastener 10 includes a pin member 12, a main sleeve or nut member 14 and an expandable sleeve 16.
- Pin member 12 has an enlarged head 18 at one end and a threaded pin shank 20.
- a pintail portion 23 is connected to the threaded shank portion 20 via a breakneck groove 26 and is formed with a thread which is continuous with that of shank portion 20.
- the threaded shank portions 20 and 23 are adapted to threadably engage mating threads in a through bore 22 of main sleeve 14.
- the expandable sleeve 16 By applying torque between the pin member 12 and the main sleeve 14, the expandable sleeve 16, which is located on the shank portion 20 adjacent the pin head 18, will be moved axially relative to the main sleeve 14.
- a pair of diametrically opposed flats 24 are provided on pin member 12 on the pintail portion 23 for accepting the chuck of a power tool (not shown) adapted to apply torque between the pin member 12 and main sleeve 14.
- the annular breakneck groove 26 is of a reduced cross-sectional area which is designed to fracture at a predetermined axial .or torsional load.
- the breakneck groove 26 is of an annular construction formed in a manner so as not to interfere with the threading of the pin 12 into the bore 22 of the main sleeve 14.
- the fastener 10 could be constructed as a pull type fastener with the pin member 12 having a generally smooth shank and a plurality of circumferential pull grooves on the free end of pin shank 19 instead of external threads and without mating threads in main sleeve or nut member 14.
- Such pull grooves are commonly employed on similar pulling pin structures and are formed to be gripped by conventional pull-type tools for exerting the necessary axial force on pin member 12.
- the main sleeve 14 is of a flush head type and includes an enlarged conical head 28, a straight shank portion 30 of generally constant outside diameter and a tapered nose portion 32.
- the tapered nose portion 32 can be formed with an angle A of between around 13° to around 17° with a line parallel with the axis X of the threaded bore 22 and of the fastener 10.
- An angle A of between around 10° to around 25° can be employed.
- the shank portion 30 of main sleeve 14 extends through aligned openings 34 and 36 in a pair of workpieces 38 and 40, respectively, with the flush head 28 designed to seat within a countersunk opening 41 in the outer or accessible surface 42 of workpiece 38.
- the outside diameter of shank portion 30 of main sleeve 14 is selected to fit through the aligned openings 34 and 36 with a relatively close tolerance fit.
- the outside diameter of the expandable sleeve 16 and pin head 18 can be accepted through the openings 34 and 36 in a clearance relationship. It is to be understood that while a flush head 28 is shown other configurations such as a protruding head may be used.
- the fastener 10 is particularly useful where the workpieces 38 and 40 are constructed of crushable materials such as composites, or the like.
- the composite materials for example can be of a graphite/thermoset resin or graphite/thermoplastic resin structure.
- the expandable sleeve 16 includes a primary sleeve section 46 adjacent the pin head 18 and a secondary sleeve section 48 having a wall of reduced thickness or cross- sectional area located adjacent the tapered nose portion 32 of main sleeve 14.
- Secondary sleeve section 48 has an outer surface 50 of a diameter Dl which is slightly larger than the diameter D2 of outer surface 52 of primary sleeve section 46.
- diameter Dl was around .6% to around 1% larger than diameter D2. This slight difference in diameter is a result of a selective cold working operation via rolling to be described and results in an outer transition surface 71.
- the inside diameter D3 of bore or bore surface 54 of secondary sleeve section 48 is greater than the inside diameter D4 of bore or bore surface 56 of primary sleeve section 46.
- the secondary sleeve section 48 defines a cylindrical column having a wall thickness 't' which is substantially less than the wall thickness 'tl' of the primary sleeve section 46; in this regard, the inner surface 54 of secondary sleeve section 48 is substantially radially offset from the inner surface 56 of the primary sleeve section 46.
- the inner surface 56 of the primary sleeve section 46 terminates at the juncture with the inner surface 54 of the secondary sleeve section 48 in a a slightly chamfered inner surface 58.
- a relative axial force is exerted by torquing the pin member 12 relative to the main sleeve 14 and expandable sleeve 16.
- the flush head 28 may include recesses 44 adapted to accept a portion of the power tool (not shown) to hold the main sleeve or nut member 14 from rotating during setting of the fastener assembly 10.
- the free end 60 of expandable sleeve 16 engages the tapered nose 32 on main sleeve 14, and as the secondary sleeve section 48 moves axially to overengage the surface of the tapered nose 32 it is radially expanded.
- the secondary sleeve section 48 continues to move axially until the free end 60 moves past and separates from the tapered nose 32; at this point the free end 60 of the secondary sleeve section 48 begins to move radially inwardly in response to hoop stresses. This action continues until the free end 60 engages the blind side surface 62 of workpiece 40. This engagement, in a sense, defines a stop surface. As more torque is applied to pin member 12, the axial column load on the secondary sleeve section 48 will increase until folding of the secondary sleeve section 48 begins.
- the leading end 58 of the hardened primary sleeve section 46 moves along and past the tapered nose portion 32, without radial inward movement, it guides the secondary sleeve section 48 to move the fold line radially outwardly resulting in a large diameter footprint.
- the "fold line” is the point at which the secondary sleeve section 48 folds over on itself and it shown as the radially outer extent 66' of the blind head 66 ( Figure 3) .
- the secondary sleeve section 48 continues to fold until it is substantially completely collapsed to define the blind head 66 in substantially full circumferential, planar engagement with the blind side surface 62 of workpiece 40 (see Figure 3) .
- This maximum diameter, substantially fully engaged bulbed head is typically around 1.5 times or greater than the original unexpanded diameter Dl of secondary sleeve section 48.
- the radial length of the footprint or engaged surface of the blind head 66 is shown in Figure 3 which also indicates the blind head 66 to have a large outside diameter DR.
- Some form of locking configuration may be provided between pin member 12 and main sleeve 14 to keep the pin member from rotating and separating axially after the fastener 10 is set and hence to maintain the preload in the fastened joint.
- the main sleeve 14 may be provided between pin member 12 and main sleeve 14 to keep the pin member from rotating and separating axially after the fastener 10 is set and hence to maintain the preload in the fastened joint.
- leading edge 60 of the secondary sleeve section 48 could include a radius or combination of curvatures which would inhibit marring of the blind side surface 62 of workpiece 40 as the bulb forms. It should also be noted that the secondary sleeve section 48 could be selectively annealed along its length LI to provide a hardness gradient between it and the primary sleeve section 46. In addition, lubricants are provided between the engaging surfaces of main sleeve 14 and expandable sleeve 16 to reduce the forces required to expand and bulb the expandable sleeve 16.
- leading edge 60 was formed with a surface inclined axially rearwardly and radially outwardly at an angle B of between around 4° to around 10° with a line transverse to the fastener axis X. It is believed that this avoids angular point contact inhibiting surface damage from highly localized loads.
- the expandable sleeve 16 could .be constructed of 304 stainless steel having strength characteristics to be defined and having dimensional characteristics within the following ranges, in millimeters, with the "-06" designating a nominal diameter for the fastener, i.e. 4.83 millimeters:
- diameters Dl through D5 and lengths LI through L5 are shown in Figure l.
- the pin member 12 could be constructed of A286 stainless steel, solution treated and aged to a minimum ultimate shear strength of around 95 KSI. It should be understood, however, that other suitable materials such as titanium alloys could be employed.
- the main sleeve or nut member 14 in one form of the invention could be constructed of 6A1-4V titanium alloy which was solution treated and aged to have a minimum ultimate shear strength of around 95 KSI.
- the pin member 12 could be provided with a major thread diameter D6 of between around 3.391 mm and 3.442 mm.
- the outside diameter D7 of pin head 18 is slightly larger than the outside diameters D2 and D5 of primary sleeve section 46. In one form the outside diameter D7 was between around 4.928 mm to around 5.004 mm.
- the underside surface 70 of pin head 18 will slightly overengage the end surface 72 of the end portion 68 of the primary sleeve section 46.
- the maximum outside diameter of fastener 10 is sufficiently less than diameters of workpiece bores 34 and 36 to facilitate initial location therein.
- the magnitude of relative axial load required to fold and eventually flatten the secondary sleeve section 48 be low in order to avoid high localized bearing stresses on the engaged blind side surface 62 of workpiece 40. This is to inhibit damage to surface 62 which, as described, is constructed - of a crushable material.
- a substantially higher axial load is desirable to provide a high clamp load and ultimately a high retained clamp load on the orkpieces 38, 40 after the fastener 10 has been set. Once the blind head 66 has been formed, however, these higher clamp loads can be applied without damage to the surface 62.
- the maximum magnitude of axial load applied to fold and collapse the secondary sleeve section 46 was no greater than around 60% of the maximum axial load to finally install the fastener 10, i.e. to cause pin break at breakneck 26.
- the expandable sleeve 16 is formed with the primary sleeve section 46 generally having a higher hardness and of a higher strength than the secondary sleeve section 48.
- the expandable sleeve 16 for the n - ⁇ 6 n size noted was constructed from a solid blank of 304 stainless steel having an outside contour generally approximating that of the expandable sleeve 16 as shown in Figure 1 but having a uniform diameter Dl.
- the blank is solution treated to have a hardness of around 65 to around 70 Rb on the Rockwell "b" scale.
- Portions of the blank corresponding to the end portion 68 and remaining portion 69 of the primary sleeve section 46 are then surface cold worked with rollers to selectively work harden those portions to a higher hardness and higher ultimate shear strength than the remainder of the blank.
- the bores 54 and 56 are drilled resulting ih the expandable sleeve 16 of the construction of Figure 1.
- the end portion 68 is rolled and work hardened slightly more than portion 69 to provide a slight further increase in hardness and strength relative to the remaining portion 69 of the primary sleeve section 46.
- the diameters D2 and D5 of portions 69 and 68, respectively, of primary sleeve section 46 are slightly, progressively smaller than diameter Dl of secondary sleeve section 48.
- the remaining portion 69 was of a surface hardness of between around 75 to around 80 Rb on the Rockwell "b" scale.
- the primary sleeve section 46 will substantially not buckle or deform radially inwardly under the required installation loads. In this way the integrity of the primary sleeve section 46 is maintained providing for the formation of a resultant blind head 66 of a large diameter with a substantial bearing area in contact with the confronting surface 62 of workpiece 40.
- a minimum differential of around 15% in hardness between the surface hardened portion 69 of primary sleeve section 46 and the secondary sleeve section 48 is desirable.
- the preceding hardnesses are by way of example for a ⁇ - ⁇ e* nominal size fastener and can vary for fasteners of different sizes and/or of different materials. It is important, however, that the relative strengths of the primary and secondary sleeve sections be constructed with the sufficient differential in strength to promote folding of the secondary sleeve section 48 while precluding radial inward movement and buckling of the primary sleeve section 46.
- Both the underside surface 70 of the pin head 18 and the sleeve end surface 72 are flat or angled slightly axially forwardly and radially outwardly at an angle C relative to a line transverse with the axis X.
- the angle C was around 7°; however an angle C of between around 0° to around 10° could be utilized. With this angulation and the slight difference in outside diameters D5 and D7 the material of the outer end portion 68 of expandable sleeve 16 will be captured underneath the pin head 18 and urged generally radially inwardly in response to the relative axial installation force.
- end portion 68 is of a higher hardness than the remaining portion 69 and in one form of the invention was of a hardness around 5 Rb higher than remaining portion 69.
- end portion 68 being of a higher hardness than the remainder of the primary sleeve section 46 it will resist deformation from the compressive forces of the confronting, engaged surface 70 of the pin 12 and thus will resist partial or complete pin pull through.
- end portion of increased hardness has been used with prior art constructions.
- the dimensional relationship of the end portion 68 to the hardened portion 69 can be determined from the prior Table I and related description.
- transition area 71 provides for a relatively smooth, tapered transition in wall thickness between the thicker walled primary sleeve section 46 and the thinner walled secondary sleeve section
- the fastener 10 of Figures 1 and 3 was depicted for securing workpieces 38 and 40 of maximum total thickness for the grip range of that fastener.
- the pin break will occur within the enlarged sleeve head 28, axially inwardly from the outer surface 74. If the softer, solution treated construction were used in such an out-of-grip condition, the collapsing of the primary sleeve section could still locate the break surface of the pin near the outer surface of the main sleeve head such that a reliable, determinable indication would not be possible; see Figure 6 and the discussion which follows.
- the fastener 10a has been shown after installation with a pair of workpieces 38a and 40a of a total thickness which is the minimum grip condition for the grip range of the fastener 10, 10a.
- the blind head 66a has been similarly formed as blind head 66 and that there has been no radially inward deformation of the leading end 58a of primary sleeve section 46a and also no column buckling of that section.
- the blind head 66a will have a desirable large footprint or engaged surface of a radial length Ra similar in extent to that length R of the embodiment of Figure 3; also the blind head 66a provides a large outside diameter DRa which is larger than diameter DR because of the greater travel involved of expandable sleeve 16a to initially engage the blind side surface 62a.
- the axial travel of the pin 12a will be greater than that of fastener 10 in the maximum grip condition of
- this determinable maximum protrusion Ya can be used to provide an indication that the correct fastener has been used for the particular combined thickness of the workpieces.
- the end surface 76, 76a will be within the specified range of
- the threaded pin shank portion 20a is threaded for a sufficient distance whereby overtravel of the pin 12a will occur if the workpieces are less than the minimum grip condition.
- the threaded portion 20a is of a length such that after the maximum desired travel of the pin 12a in the minimum grip condition of Figure 5, there will still be at least around two full threads remaining between the pin head 18a and the nose portion 32a; this will assure that the pin 12a will have the capability of overtravelling in an out-of-grip which is less than minimum grip whereby it can flag or indicate an improper installation, i.e. for workpieces of a total thickness less than the minimum grip condition for the fastener.
- FIG 6 a fastener 10b having a configuration generally similar to fastener 10, 10a is shown in an installed assembled relationship with workpieces 38b and 40b having a combined thickness defining the maximum grip condition for the grip range of the fastener.
- the primary sleeve section 46b has buckled and the leading end 58b has deformed radially inwardly.
- the leading end 58b begins to deform radially inwardly as it moves past the tapered nose portion 32b of the main sleeve or nut member 14b. This is responsible for the deflection of the folded portion 66b' away from the surface 62b.
- blind head 66b having a footprint or engaged area of a radial length Rb which is substantially less than the radial lengths R, Ra of the embodiment of the present invention of Figures 1-4 and 5.
- this radial inward deflection of the primary sleeve section 46b results in the blind head 66b having an effective outside diameter DRb which is substantially smaller than diameters DR and DRa.
- the fractured end 76b of the pin shank portion 20b will extend a distance Yb which is not determinable within a reasonably effective range because of the unpredictability of the amount of buckling of the primary sleeve section 46b.
- the buckling could be to such an extent that the pin head 18b would engage the tapered nose portion 32b.
- the protrusion Yb could incorrectly indicate a proper installation.
- FIG. 7 a fastener 10c being of the same configuration and construction of fastener 10b is shown in assembled relationship with workpieces 38c and 40c having a combined thickness defining the minimum grip condition for the grip range of the fastener.
- the primary sleeve section 46c has buckled and the leading end 58c has deformed radially inwardly.
- the leading end 58c begins to deform radially inwardly as it moves past the tapered nose portion 32c of the main sleeve or nut member 14c.
- blind head 66c having a footprint or engaged area of a radial length Re, which as with blind head 66b, is substantially less than the radial lengths R, Ra of the embodiment of the present invention of Figures 4 and 5; similarly, the blind head 66c provides an effective outside diameter DRc which is substantially smaller than diameters DR and DRa.
- the fractured end 76c of the pin shank portion 20c can extend a distance Yc which is excessive and which is not determinable within a reasonably effective range because of the unpredictability of the amount of buckling of the primary sleeve section 46c.
- variations in buckling and hence final pin position could provide a protrusion similar in length to Yc.
- the protrusion Yc would not reliably provide an indication that the fastener has been used in a proper or improper grip condition.
- the primary sleeve section 46b, 46c buckles and deforms radially inwardly.
- the resistance of this buckled and deformed structure to twisting and bending loads, which can occur when the fastened workpieces are subjected to lap shear loads, will be less than that of the fastener 10, lOa constructed in accordance with the present invention.
Abstract
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BR909007706A BR9007706A (en) | 1989-10-02 | 1990-09-12 | BLIND RETAINER WITH LARGE SUPPORT AREA |
KR1019920700764A KR920704026A (en) | 1989-10-02 | 1990-09-12 | Blind fasteners with large bearing area |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US07/415,744 US4950115A (en) | 1989-10-02 | 1989-10-02 | Blind fastener with expandable sleeve forming a blind bulbed head with large bearing area and a pin having a controlled protrusion length |
US415,744 | 1989-10-02 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991005172A1 true WO1991005172A1 (en) | 1991-04-18 |
Family
ID=23647013
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1990/005161 WO1991005172A1 (en) | 1989-10-02 | 1990-09-12 | Blind fastener with large bearing area |
Country Status (10)
Country | Link |
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US (1) | US4950115A (en) |
EP (1) | EP0495002A1 (en) |
JP (1) | JPH05502926A (en) |
KR (1) | KR920704026A (en) |
AU (1) | AU6713390A (en) |
BR (1) | BR9007706A (en) |
CA (1) | CA2066681A1 (en) |
IE (1) | IE903505A1 (en) |
IL (1) | IL95802A0 (en) |
WO (1) | WO1991005172A1 (en) |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
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US4457652A (en) * | 1981-04-13 | 1984-07-03 | Pratt John D | Composite buckling blind fastener |
-
1989
- 1989-10-02 US US07/415,744 patent/US4950115A/en not_active Expired - Lifetime
-
1990
- 1990-09-12 EP EP90916637A patent/EP0495002A1/en not_active Ceased
- 1990-09-12 JP JP2515490A patent/JPH05502926A/en active Pending
- 1990-09-12 CA CA002066681A patent/CA2066681A1/en not_active Abandoned
- 1990-09-12 WO PCT/US1990/005161 patent/WO1991005172A1/en not_active Application Discontinuation
- 1990-09-12 BR BR909007706A patent/BR9007706A/en unknown
- 1990-09-12 AU AU67133/90A patent/AU6713390A/en not_active Abandoned
- 1990-09-12 KR KR1019920700764A patent/KR920704026A/en not_active Application Discontinuation
- 1990-09-26 IL IL95802A patent/IL95802A0/en unknown
- 1990-10-01 IE IE350590A patent/IE903505A1/en unknown
Patent Citations (3)
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US4089247A (en) * | 1976-06-25 | 1978-05-16 | Standard Pressed Steel Co. | Blind fastener |
EP0152531A1 (en) * | 1984-02-23 | 1985-08-28 | Monogram Industries, Inc. | Blind fastener |
GB2168122A (en) * | 1984-12-04 | 1986-06-11 | Avdel Ltd | Blind fastener |
Also Published As
Publication number | Publication date |
---|---|
BR9007706A (en) | 1992-07-21 |
EP0495002A1 (en) | 1992-07-22 |
CA2066681A1 (en) | 1991-04-03 |
US4950115A (en) | 1990-08-21 |
JPH05502926A (en) | 1993-05-20 |
AU6713390A (en) | 1991-04-28 |
KR920704026A (en) | 1992-12-19 |
IE903505A1 (en) | 1991-04-10 |
IL95802A0 (en) | 1991-06-30 |
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