JP5602205B2 - Fastener - Google Patents

Description

  The present invention relates to a fastener, and more particularly, to a fastening system having a swage-type fastener having a multi-member structure and a swaging tool, and presenting an optimum balance between a low swage load and high strength. . The present invention also relates to a simple installation method using a low swage load fastening system.

  In many commercial applications, two-part threaded or swaged fasteners, commonly known as lock bolts, are used to secure multiple workpieces together. Reference examples include U.S. Pat. Nos. 2,531,048, 3,215,024, 3,915,053, 4,472,096, and 5,090,852. The material properties of these fasteners (non-limiting examples are tensile strength and hardness) vary depending on the commercial application in which the fastener is used. In order to distinguish the various properties of fasteners, fasteners are typically labeled with grades. Fastener grade is an indicator of its strength. Industry standards establish the strength that fasteners need to conform to a particular grade, and the strength of individual fasteners is determined by the strength of the materials of the fastening bolts and fastening pins. For example, a 1/2 inch Grade 5 fastener has a 1/2 inch diameter pin or bolt shank portion for use in opening a 1/2 inch nominal diameter workpiece and is SAE Standard J429 Grade 5 Or in accordance with ASTM standard A-325, such a grade 5 fastener must have a minimum tensile strength of 120 KSI (kiloponds per square inch). By comparison, in order to be compatible with SAE J429 Grade 8 or ASTM Standard A-490 Grade 8 fasteners, the fasteners must have a minimum tensile strength of 150 KSI. Grade 5 fasteners are frequently used in scenes such as railroads (eg, railroad trains). Grade 8 fasteners are typically used in commercial transportation situations, for example, to secure truck parts in the commercial truck industry.

  Typically, swage type fasteners have pins and collars. Most of these fasteners are tension-type variants and include a pin shank, which includes a locking portion having a locking groove and a pulling portion having a pulling groove. These tension grooves are suitable for being gripped by the corresponding teeth of the chuck jaws of the installation tool with a swage anvil. The swage anvil is suitable for engaging the collar to provide a relative axial force between the pin and the collar, and for moving over the collar to swage the collar into the locking groove. The relative axial force consists of a combination of a tensile load on the pin due to the chuck jaws and a compressive load on the collar due to the swage anvil. The pull portion of many swage-type fasteners is connected to the lock groove portion through a reduced strength break groove. The break groove is configured to break when the axial force or tension reaches a preselected size (greater than that required for swaging the collar). Thus, the tensioned portion or pin tip is broken and removed from the pin shank upon completion of swaging. In addition, there are swage fasteners that have tension portions that remain on the pins after installation is complete. In this regard, reference may be made, for example, to US Pat. Nos. 5,315,755, 5,548,889, and 5,604,968, which disclose thread tension portions that are not cut from the pins. That is, these fasteners do not have pin tips, as can be seen from FIGS. 1-8 of US Pat. No. 5,315,755, for example.

  Often a problem in swage type fasteners of relatively high strength (eg grade 5 and above) is that a fairly large tensile load is required to fully swage the collar. This leads to premature wear of the installation tool, in particular the tensile structure, and peeling of the pulling groove of the pin. Also, high swage loads generally complicate the installation process, especially when manual installation tools are used. In an attempt to overcome some of these drawbacks, various installation tool modifications have been made. For example, U.S. Pat. No. 4,299,519, which is hereby fully incorporated by reference, discloses an akon shaped pin pulling portion and a tool gripping structure that forms a complementary pair therewith. The gripping structure of the tool brings about engagement with all the tension grooves in the tension portion, and is configured to withstand peeling of the tension grooves. In this regard, reference can be made, for example, to FIGS. 1-5 of US Pat. No. 4,299,519. Other tools simply incorporate hydraulic and / or pneumatic piston cylinders as an aid to apply the necessary swaging force. Reference can be made, for example, to U.S. Pat. Nos. 4,597,613 and 4,878,372. However, this can make the tool larger and heavier, which can be inconvenient and limited in accessibility, potentially resulting in precise application when using the fastener and the resulting end result. The installation quality is dangerous. Thus, there is room for improvement in methods for installation tools and swage type fastening systems.

The primary cause of high swage loads is that the walls are thick, so that the locking groove is overfilled or overfilled to reach the required strength of certain fastener grades (eg grade 5 or grade 8). The use of a fastener collar configured in the above. As an example, the above-mentioned U.S. Pat. No. 5,090,852 (discloses an improved pin thread shape with shallow groove and streamlined groove bottom shapes, the tube thickness of the collar being thick to achieve the required shear strength, It has sufficient material to overfill such shallow grooves). Also, US Pat. No. 5,315,755, US Pat. No. 5,548,889, and US Pat. No. 5,604,968 (a shallow pin groove structure and a color shank having an amount of at least 16% excess material to overfill the groove. See also (disclosed). There are many problems with overfilling the lock grooves. This is due to the above-mentioned non-ideal excessive high swage load. Therefore, several attempts have been made to overcome these drawbacks and, in particular, extremely high swage loads, by modifying the design of the swage type fasteners.

  For example, U.S. Pat. Nos. 6,233,802 and 6,497,024, which are hereby fully incorporated by reference, are fastening systems for two-part swage type fasteners having a width of Has a wide and shallow lock groove thread shape, so that the fasteners can be installed at lower swage loads compared to conventional swage type fasteners of the same grade, but basically the same physics when installed. Fastening systems that retain the desired properties (eg, tensile strength and clamp load) are disclosed. Since the swage load is low, a small and lightweight installation tool can be advantageously used. This system can be applied to a fastener with a pin tip or a fastener without a pin tip. A pull-type swage fastener with a threaded tension portion that is not broken does not require additional force to break the break groove, as described in US Pat. No. 5,315,755. It is said that it helps to engage fewer threads at the tension. By using such a configuration, (1) the stress applied to the thread that engages the thimble (metal ring) or the nut member with the screw thread of the tension tool is reduced, so the tool life is increased, 2) Since the number of pulling grooves to be gripped is reduced, the protruding portions of the pins required to grip these can be shortened, so that shorter and cheaper pins can be used. (3) Necessary for final installation Since the applied load applied is small, it is said that the installation tool can be made small, and therefore lightweight and inexpensive. This system also facilitates the use of the inner drive. See, for example, FIGS. 17 and 18 of US Pat. No. 5,315,755 (illustrating an inner drive structure with a threaded tension rod or spindle that can mate with a threaded tension groove in the end of a pin shank). Use such an inner drive as detailed in US Pat. Nos. 5,315,755, 5,548,889, and 5,604,968, which are incorporated herein by reference as if fully set forth by reference. As a result, the protruding portion can be made smaller than the outer drive unit. Using an outer drive instead makes the final engagement and appearance of the fastener more effective.

  However, as disclosed in the above-mentioned US Pat. No. 6,497,024, in order to achieve the above-mentioned advantages, it was necessary to change the thread shape (for example, a lock groove structure) to a wide and shallow form. Modifying the thread shape is feasible as an option to reduce the swage load, but the thread disclosed in the aforementioned 6497024 is a significant change, with a significantly larger pitch and multiple Different radii, relatively abrupt changes between radii, and transitions discontinuously (eg from one radius to another). For this reason, it is difficult and costly to produce a pin having the disclosed thread shape. Furthermore, the discontinuous transition between thread-shaped radii prevents maximizing thread-shaped complementary engagement by the collar groove when the fastener is swaged. For this reason, there is still room for improvement in the thread shape for the pin lock groove.

  In addition, in the types of collars disclosed in US Pat. Nos. 6,233,802 and 6,497,024, if the hardness is too high, the swage load becomes extremely high, and if the hardness is too low, the strength becomes insufficient. Hardness is limited to a fairly narrow range. In particular, higher grade fasteners (eg grade 5 and above) are required to have both bolts and collars with increased hardness to meet the tensile strength requirements in the industry. Configurations that are limited to a narrow range are problematic. Thus, conventional collars must be subjected to heat treatment in order to be soft enough to swage, be compatible with modified thread shapes, and have strength that meets industry grade standards. This makes the manufacture of fasteners more expensive and complex. For example, considering two such heat treatment methods, including stress relief and quenching / tempering, it is very difficult to achieve a desired hardness stably by stress relief, and quenching / tempering is It is expensive and is very difficult to complete without carburizing or decarburizing the surface of the collar. Both of these methods are time consuming and costly, for example requiring additional furnace operation costs.

  From such circumstances, a fastening system with a high strength and a low swage load is disclosed in the above-mentioned U.S. Pat. Nos. 4,299,519, 5,315,755, 6,233,802 and 6,497,024, among other characteristics. It would be highly desirable to provide a fastening system that provides all the advantages of a low swage fastener, but which is time consuming and costly and does not require heat treatment of the collar.

  Thus, there is room for technical improvement in a fastening system with high strength and low swage load.

  One object of the present invention is to provide a swage type fastener that exhibits an optimal balance between low swage load and high strength.

  Another object of the present invention is to provide a fastener using a forged (as-headed) collar that does not require heat treatment (eg, quenching / tempering, stress relief).

  Another object of the present invention is to provide a high-strength collar having a small wall thickness and thus a light weight and a low swage load while maintaining strength.

  Yet another object of the present invention is to provide a forged collar that has sufficient physical properties (eg, hardness and strength) to meet the desired fastener grade (eg, grade 5 or grade 8). is there.

  Another object of the present invention is to provide a collar that can be used with an existing fastener and its thread form and that exhibits the required strength of a desired grade (as a non-limiting example, Grade 5 or Grade 8). is there.

  Another object of the present invention is to reduce the swage load required to set the fastener, thereby reducing the components of the installation tool (as a non-limiting example, a swage anvil, thimble) and It is to reduce the wear of the half shell) and extend the tool life.

  Another object of the present invention is to provide a fastener that can omit an expensive heat treatment step (for example, stress removal, quenching, and tempering) in the fastener collar.

  Yet another object of the present invention is a part of a new or existing item that can be retrofitted with a collar, including, but not limited to, fasteners with pin tips and fasteners without pin tips. It is to provide a collar that can be used with various forms of swage type fasteners.

  Another object of the present invention is to increase the hardness of the collar in order to reduce the swage load while maintaining or improving the strength level of the collar by not overfilling the lock groove of the fastener pin.

  It is yet another object of the present invention to provide an improved fastener locking groove thread shape designed to overcome the disadvantages experienced in conventional shallow or corrugated thread shapes.

  Another object of the present invention is to provide a lock groove thread shape that is configured to reduce swage load, while being relatively simple to manufacture and therefore economical.

  Yet another object of the present invention is to provide complementary pull groove and tool gripping structure shapes that provide some of the advantages by improving engagement between the pull groove and the gripping structure, among other advantages. In particular, for example, by reducing the diameter of the pin tension part and enlarging the thimble cross section, increasing the thickness and strength of the tension thread and minimizing the protruding length of the pin tension part This extends the useful life of the gripping structure (eg, thimble).

  Accordingly, it is a primary object of the present invention to provide an improved, high strength swage type fastener and a forged collar for the fastener, which can be reduced by existing tools with a low swage load. And exhibits optimum material properties (eg, hardness and strength) at the desired fastener grade. It is also a main object of the present invention to provide a low swage load fastening system with at least one of a forged collar, an improved pin pull and installation tool shape, and an excellent fastener thread shape. It is in.

  These and other objects are achieved by the present invention which provides a low swage load fastening system and method.

  In one embodiment of the invention, the fastener of this system has a collar with high hardness and thin wall thickness that is suitable to avoid overfilling the lock groove. This collar can be produced very economically compared to known fasteners of comparable grade and can be easily swaged. This is because the collar of the present invention is used as it is forged, so that no expensive heat treatment (for example, quenching / tempering or stress removal) is required. This collar also does not require modification of the thread shape of the pin lock groove. Therefore, this collar can be easily used with existing pins and installation tools with various lock groove thread shapes, and the thin wall makes the installation tool less The service life of the instrument is increased and / or the installation tool is lighter and easier to handle. The fasteners and collars therefor exhibit all of the aforementioned effects while exhibiting surprising and unexpected high strength performance sufficient to meet grade 5 and grade 8 industrial fastener standards.

  Thus, this low swage load fastening system is for a swage type fastener configured to secure a plurality of workpieces together. The swage-type fastener includes a pin member having an elongated pin shank suitable for placement within an aligned opening in the workpiece. One end of the pin member terminates in an enlarged head suitable for engaging a surface on one side of the plurality of workpieces, and the other end is on the opposite side of the plurality of workpieces, Terminate with a grooved section suitable for extending past the opposite surface. The grooved portion of the pin comprises a locking portion having a plurality of locking grooves defined by a circumferentially extending pin groove and associated pin shoulder terminating at a pink rest (pin top). Yes.

  The fastener can be selected from the group consisting of fasteners with pin tips and fasteners without pin tips. In addition, the grooved portion of the pin of the fastener may have a female threaded screw hole without having a pin tip, and in this case, the installation tool is screwed into the screw hole while swaging the fastener. An inner drive unit configured as described above is provided.

  In another embodiment of the present invention, the low swage load fastening system comprises a pin that is a substantially straight tension portion with a plurality of tension grooves extending from the second end of the pin. Have The outer diameter of the tension portion is smaller than the outer diameter of the lock portion of the pin. A related installation tool has a collet with a tension part for complementary engagement with the tension groove of the tension part. The length of the protruding portion protruding from the end of this pin is relatively short. For this reason, the tensile portion can be left on the pin even after swaging, or it can be cut off, or removed by breakage in a break groove optionally provided in the pin. Due to the small diameter of the tension part, the installation tool becomes thicker and stronger. Further, since the tension portion is straight, excellent engagement with the installation tool is possible.

  The diameter of the first tooth of the tension portion of the installation tool may be larger than the other teeth of the tool, which extends the tool's useful life. This tool is further improved by providing a relatively small swage load, and the swage load can be further reduced.

  In yet another embodiment of this low swage load fastening system, the thread form of the fastener pin is defined by having a plurality of different radii, and the thread form between each radius is substantially smooth. It may be migrated. This improves the fit into the groove when the collar is swaged. In this type of thread shape, the thread rolling die used for thread rolling is not complicated.

  Another aspect of the invention disclosed in this specification is a low swage load fastening system for a swage type fastener configured to secure a plurality of workpieces together. The swage-type fastener includes a pin member having an elongated pin shank suitable for placement within an aligned opening in the workpiece. One end of the pin member terminates in an enlarged head suitable for engaging a surface on one side of the plurality of workpieces, and the other end is on the opposite side of the opposite side of the plurality of workpieces Terminate with a grooved portion suitable for extending past the surface of the substrate.

  The grooved portion includes a locking portion having a plurality of locking grooves defined by a circumferentially extending pin groove and associated pin shoulder terminating at a pink rest (pin top). .

  The installation tool includes an anvil member having a swage cavity. The collar is also swaged into the lock groove of the pin member in response to a relative axial force or swage load applied between the pin member and the forged collar by the installation tool. Equipped with a generally straight color shank suitable for

  A desired amount of clamping load applied to the workpieces that are fixed together defines the joint to be fastened. The swaging cavity of the installation tool is configured to engage the collar shank and swage (squeeze) it radially inward. The forged collar has a collar groove and a shoulder that engages with the pin groove and the pin shoulder when swaged. The pin member and the forged collar are made of different materials having different magnitudes of maximum shear stress so that yielding of the pin member is substantially avoided when swaging the collar on the pin member. .

  The collet has a protruding portion from the collet, whereby the length of the collet pulling portion extends in the collar direction, thereby increasing the contact area with the anvil.

  The forged collar does not require heat treatment, and the wall thickness of the generally straight color shank of the forged collar is relatively thin, reducing the swage load required for the forged collar.

  The projecting portion forms an annular flat surface adjacent to the front of the tip thread of the collet, an annular front inclined surface is provided in front of the flat surface, and the second flat surface and the collet There is an inclined flat surface that returns to the line of intersection with the diameter.

  The end of the pin tension is not thinned to a diameter position coinciding with the bottom of the groove, thereby increasing the shear strength of the end tensile crest (top).

  In a further different aspect, the final tensile crest of the pull has a contour that matches the expanded pull radius of the final teeth of the collet.

  All of the aforementioned low swage load structures may be used individually or in any suitable combination. Also disclosed is a swage-type fastener and method for securing a plurality of workpieces together using the low swage load system described above.

  A comprehensive understanding of the invention can be obtained by reading the following description of preferred embodiments of the invention in conjunction with the accompanying drawings.

FIG. 4 is a cross-sectional view of a low swage load fastening system and upset forging collar therefor according to an embodiment of the invention when used in a swage type fastener having a pin with a removable pin tip. . FIG. 2 is a cross-sectional view of the low swage load fastening system shown in FIG. 1 and the upset forging collar for use in a swage type fastener without a pin tip. FIG. 4 is a cross-sectional view of the low swage load fastening system and the upset forging collar for it shown in FIG. 1 in another embodiment of the present invention when used in a swage type fastener without a pin tip. FIG. 3 is a plan view of a collar for a swage type fastener in the prior art. FIG. 4 is an isometric view of the upset forged collar shown in FIGS. 1-3 having a reduced wall thickness in accordance with an embodiment of the present invention, with a small tube thickness according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a corrugated lock groove thread shape. It is a cross-sectional sample figure of a deep lock groove thread shape. It is a cross-sectional sample figure of a hybrid lock groove thread shape. FIG. 6 is a cross-sectional view of an improved fastener pin tension portion and installation tool shape, in accordance with an embodiment of the present invention. It is sectional drawing of the edge part of the collet for the installation tool shown in FIG. It is sectional drawing of the anvil member shown in FIG. FIG. 6 is a cross-sectional view of an improved fastener pin tension portion and installation tool shape, in accordance with an embodiment of the present invention. FIG. 11 is a cross-sectional view of the end of the different collet for the installation tool shown in FIG. 10.

  As used herein, directional expressions such as upper, lower, forward, rearward, etc. relate to the arrangement of the elements shown, and do not limit the scope of the claims.

  As used herein, the term “plurality” refers to singular or more (eg, plural).

  As used herein, the term “as-headed” refers to a color that has been strain-hardened by, for example, cold forging rather than changing the hardness by heat treatment (eg, quenching, tempering or stress relief). Refers to that. The collar of the present invention exhibits high strength (for example, strength of grade 5 or 8) while heat treatment is unnecessary.

  As used herein, the expression “low swage load” refers to similar grades due to the characteristics of the fastening system of the present invention (eg, forged collar, small pin tip tension, modified thread shape). It is an expression used for comparison purposes to explain that the required swage load is reduced compared to the conventional fasteners. Representative examples of such low or reduced swage loads are represented numerically in the tables and corresponding disclosure herein.

  Similarly, the expression “reduced wall thickness” as used herein refers to a structure in which the wall thickness of the collar of the present invention is thinner compared to a collar of a conventional fastener of similar grade. It is an expression used for the purpose of comparison, which is explained. For example, the wall thickness of the exemplary collar is thin and the amount of material is small, so that unlike many known fasteners, the lock is not overfilled.

  As used herein, the term “pull portion” refers to an exemplary pin pull portion of a fastener pin and a complementary pull portion of an installation tool that engages the pin pull portion. As will be described later in this specification, an exemplary tensile portion shape comprises a substantially straight, small diameter, parallel on both sides, such as, for example, U.S. Patents incorporated herein. Compared to the tapered Akon-shaped pulling portion of No. 4,299,519 and the portion of the tool that complements this, the length protruding from the end portion of the lock groove portion of the pin is short.

  As used herein, the expression “thread shape” refers to an exemplary improved pin lock groove thread shape of the present invention. Among other new features, this new thread shape is hybrid in that it is, in a sense, a hybrid of certain features of various thread shapes. However, it will be appreciated that various tests and experiments were required to develop this exemplary hybrid thread shape and achieve its benefits that could be contributed in this context.

  Although the fasteners in the embodiments of the present invention are defined with respect to a certain size, i.e., nominal diameter, the concept can be easily applied to fasteners of various sizes (e.g., diameter and length). it can.

  As shown in FIGS. 1-3 and 7, the present invention is based on multiple parts (eg, pins and collars), such as the fastener described in the above-mentioned US Pat. No. 6,497,024, incorporated herein by reference. To a swage type fastener. 1-3, 6B, 6C, and 7, the equivalent fastener parts are numbered the same in each figure, except that the distinguishing alphabets “a” (FIG. 2), “b” (FIG. 3). ), “C” (FIG. 6B), and “d” (FIGS. 6C and 7), and unless otherwise specified, are considered substantially the same. The first features of the exemplary low swage load fastening system 50 and the forged collar 14 are shown in FIGS. 1, 2, 3, 6B, 6C and 7, respectively, as fasteners 10, 10a, 10b, 10c, 10d. It is shown in the state used for each of.

  FIG. 1 shows a fastener 10 comprising a pin member 12 having a pin tip 41 and a forged low swage load collar 14 of the present invention. Pin member 12 has an elongated shank 15 that extends through a pair of aligned openings or holes 16 and 17 in workpieces 18 and 20 to be secured to each other. A head 22 that is widely raised at one end of the shank 15 engages a back surface 23 of the workpiece 18. The shank 15 has a straight and smooth cylindrical shank portion 24 adjacent to the head portion 22 that is received in a clearance fit in the aligned holes 16 and 17. Is suitable. However, it is understood that depending on installation conditions, the size of the straight shank portion 24 can be determined to provide a tight tolerance or interference fit with respect to one or both of the holes 16 and 17. Let's go. The straight shank portion 24 is adjacent to and integrally joined with a lock shank portion 25 having a plurality of annular lock grooves 26 extending in the circumferential direction.

  The fastener 10 shown in FIG. 1 includes a pin tip or tension shank portion 41 having a straight annular land 42 followed by a plurality of annular tension grooves 44 as described above. The fracture groove 40 having a small valley diameter is located between the lock portion 25 and the annular land 42 of the tension portion 41, and this is the weakest cross section of the pin shank 15. The diameter Da of the tension portion 41 including the land 42 and the tension groove 44 is smaller than the diameter Db of the crest 71 of the lock groove 26 of the lock portion 25. The diameter Db is equal to the diameter of the straight shank portion 24. However, in applications where the holes 16 and 17 are not shown but fitted with a marginal tolerance or a slight interference fit, the diameter of the crest 71 of the lock groove 26 is greater than the diameter of the straight shank portion 24. It will be understood that they are also small (not shown). The pull groove 44 is suitable for being gripped by the installation tool 100 used in installing the fastener 10 in the manner shown and described in US Pat. No. 6,497,024.

  The tool 100 required for installation (e.g., swaging) of the collar 14 can generally be constructed in a manner known to those skilled in the art and is therefore only partially illustrated for the sake of brevity. In overview, the tool 100 includes a nose assembly 102 having a plurality of circumferentially spaced jaws 104. This jaw 104 is suitable for gripping the pulling groove 44 of the pulling shank portion 41. The jaw 104 is disposed inside a tubular collet assembly 106 that is slidably supported within the anvil housing 108, with one end of the anvil housing 108 terminating at a swage anvil portion 110 having a swage cavity 112. Typically, the jaw 104 is elastically biased axially forward by the jaw follower assembly 116 (partially shown in FIG. 1) within the conical track 114 toward the illustrated position of radial convergence. . However, as discussed herein, other suitable installation shapes other than those shown and described with respect to FIGS. 1-3 (e.g., the small diameter pin tip tension portion 177 shown in FIGS. Reference) and method are also preferred when recalled from this exemplary low swage load fastening system 50.

  2 and 3 show an exemplary collar 14 used in two representative examples of fasteners 10a, 10b without pin tips, respectively. Furthermore, these figures show how the exemplary collar 14 can be easily used with a wide variety of existing installation tools. For example, FIG. 2 shows an installation tool 200 that includes an outer drive 202 having an internally threaded screw hole 204 and a detection rod 206. This installation tool 200 is also described in detail in US Pat. No. 6,497,024, which description is incorporated herein. In general, the outer drive 202 engages the groove 26a and drives or exerts a relative axial force on the swage anvil 210 so that the collar 14 is received within the swage cavity 212 of the swage anvil 210 and the workpiece. Swage anvil 210 swages collar 14 so that 18a and 20a are secured together.

  FIG. 3 shows an exemplary collar 14 used in another type of pinless fastener 10b. The pin shank 15b is a female threaded screw hole 77 suitable for use with an installation tool 300 having an inner drive 306 with a drive rod 302 having a thread 304 corresponding to the thread of the female threaded screw hole 77. Is provided. Such an installation tool is also described in US Pat. No. 6,497,024. In summary, the inner drive 306 of the installation tool 300 engages the internally threaded screw hole 77 of the pin shank 15 b and pulls the swage anvil 310 toward the collar 14, so that the collar 14 is within the swage cavity 312. Accepted and swaged.

  Accordingly, the forged low swage load collar 14 of the present invention includes a wide variety of fasteners and tools for the fasteners, including fasteners with pin tips and fasteners without pin tips. These fasteners and tools can be used in conjunction with the improved thread shape shown in FIGS. 2 and 3 and described in connection with the invention described in US Pat. No. 6,497,024 above. It has a conventional annular or helical lock groove thread shape with deeper, narrower grooves or shorter pitch. This is an important advancement. This is because, as briefly described below, the fastener structure of US Pat. No. 6,497,024 reduces the required swage load to a size that can be handled. The collar needs to be changed and the collar is subjected to heat treatment (eg quenching / tempering and stress relief) to obtain the necessary material properties (eg strength). Although the collar 14 of the present invention is applicable to fasteners having the above-described modified thread form (eg, shown in FIGS. 2 and 3), conventional or standard screws with narrow and deep locking grooves It can also be easily used for a fastener having a mountain shape. See FIGS. 7 and 7A and the invention disclosed in US Pat. No. 6,497,024. As will be described later in this specification, the exemplary forge collar 14 may also be easily used with the improved hybrid thread shape 26d (FIG. 6) of the exemplary fastening system 50 of the present invention. it can.

  4 and 5 illustrate a known prior art collar (eg, 14 ') in comparison to the exemplary collar 14 of the present invention. The collar 14 ′ includes an enlarged flange 59 ′ having an arbitrary diameter together with a cylindrical shank 61 ′ and a through hole 65 ′. The color shank 61 'has a substantially uniform cylindrical shape with a substantially uniform wall thickness t'. The collar 14 'has a straight shank portion 69' whose outer end terminates in a radially outwardly extending shank portion 67 '. This shank portion 67 'is also of a substantially thickness t'.

  Like the exemplary collar 14 of the present invention (FIGS. 1-3, 5, 7), before being swaged, the collar 14 'is suitable for placement outside the pin shank 15 (eg, FIG. 1), together with the workpieces 18, 20 (FIG. 1), the collar shank 61 'is aligned radially with the locking groove 26 (FIG. 1). At the same time, the flange 59 ′ engages the outer surface 73 of the workpiece 20. The total thickness t1 (FIG. 1) of the workpieces 18 and 20 defines the nominal grip of the fastener (eg, 10). However, the fastener 10 is used over a predetermined grip range from a workpiece (not shown) having a minimum total thickness smaller than t1 to a workpiece (not shown) having a maximum total thickness larger than t1. It will be understood that it can be done.

  As discussed in US Pat. No. 6,497,024, which is incorporated herein by reference, the relative axial load required to swage the color shank is a straight collar hole portion 69 'of uniform diameter, and It is minimized by reducing the gap between the lock groove 26 and the crest 71 (see, for example, FIG. 1). In the invention of US Pat. No. 6,497,024, this radial clearance is particularly reduced in the radial direction, about half that of a conventional rock bolt. See, for example, FIG. 7 of US Pat. No. 6,497,024 (showing the thread shape of a typical swage-type fastener). Due to the small radial clearance provided by the minimized inner diameter ID ′, the outer diameter OD ′ can be limited to that of the thickness t ′ required to provide the desired volume. Thus, as discussed in US Pat. No. 6,497,024, the inner diameter ID ′ and the outer diameter OD ′ are selected to provide the desired wall thickness t ′ of the color shank 61 ′, thereby providing the color material required for swaging. The amount and the desired amount of lock groove filling, while providing the desired reduction in swage load.

  However, as shown in FIGS. 4A, 7A, 8A and 9A of US Pat. No. 6,497,024 and discussed in that specification, such fasteners and collars 14 ′ therefor are provided with locking grooves 26. Of the improved groove structure (the improved groove structure shown in FIGS. 4A, 8A and 9A of US Pat. No. 6,497,024 is similar to that of the prior art shown in FIG. Wide (relative to fasteners) and generally shallow. In addition, the improved fastener thread shape contributes to overcoming the high swage loads described above, but it also provides the collar 14 'to maintain the necessary material properties (eg, strength). High cost heat treatment is required.

  Thus, from the perspective of previous attempts to improve the design of swage type fasteners, the technical field of such fasteners is an economic and demonstrating the optimal balance between low swage load and high strength. Producing high-grade fasteners has long been a well-known desire. While the fasteners described above serve the purpose of substantially reducing the swage load, so far this has been achieved only by costly collar heat treatment and thread shape improvements. The low swage fastening system 50 of the present invention, among other methods, overcomes these drawbacks because it can be easily used with a wide variety of existing fasteners and thread forms therefor, and can be forged. By providing the improved collar 14 described above that exhibits high grade (e.g., grade 5 and grade 8) material properties (as a non-limiting example, strength), while not requiring heat treatment. Thus, the collar 14 can be retrospectively used with existing fasteners as an improved independent component or alternatively in combination with other low swage features of the exemplary fastening system 50. .

  FIG. 5 is a more detailed illustration of an exemplary forged low swage load collar 14 being used with the fasteners 10, 10a, 10b, 10c, 10d of FIGS. 1-3, 7 respectively. Shown in an isometric perspective view. A portion of the collar 14 is cut away to show an illustratively reduced wall thickness t of the collar 14 (eg, compared to the thickness t 'of the collar 14' shown in FIG. 4). Thus, for fasteners of the same grade, the inner diameter ID of the collar 14 of the present invention is the same as the inner diameter ID 'of the collar 14' shown in FIG. It is substantially equal to Db. However, the outer diameter OD of the exemplary collar 14 is smaller than the outer diameter OD ′ of the prior art collar 14 ′, resulting in a reduction in the exemplary wall thickness t of the color shank 61. As will be described in more detail above, as the wall thickness t is reduced, it is swept into the lock grooves (26, 26a, 26b, 26c, 26d shown in FIGS. 1-3, 6B, 6C and 7 respectively). The amount of material that should be reduced. This, coupled with the increased hardness of the exemplary collar 14, results in not overfilling the locking grooves (eg, 26, 26a, 26b, 26c, 26d), which is the color design of many prior art. And the opposite. Also, by reducing the inner diameter ID of the collar, the distance that the collar moves during engagement with the lock groove during swaging is reduced. Since the clearance from the outer shape of the crest to the collar is less than in the prior art, the swage load consumed when swaging the collar of the present invention into the lock groove is less. In prior art lock bolt systems, the gap between the collar and the outer diameter of the crest was larger, so more swage load on the collar before the collar passed through the gap air and swaged into the lock groove Had been put on. The reduced wall thickness t that does not overfill the locking grooves 26, 26a, 26b, 26c, 26d and the reduced clearance between the collar and the outer diameter of the crest of the locking bolt swage the exemplary collar 14. To reduce the relative axial load required for

  Thus, the present invention completes the reduction of swage load to a similar point in a more economical and improved manner than the known prior art. The exact difference or reduction of the wall thickness t of the exemplary collar 14 compared to, for example, the tube thickness t 'of the collar 14' is dependent on the size of the fastener in question (1/2 inch as a non-limiting example). , 5/8 inch, 3/4 inch). For example, the difference in color wall thickness tends to be greater in pairs of equivalent grade 3/4 inch fasteners than in pairs of equivalent grade 1/4 inch fasteners, for example. The effect of reducing the thickness t of the color shank 16 of the present invention and examples of representative values of the thickness t will be described and understood in more detail in the examples described below. These embodiments evaluate the effect of reducing the wall thickness t of the color shank 61 in the forged and unstretched high-strength collar 14 and fasteners (eg, 10, 10a, 10b, 10c, 10d). The results of some experiments carried out for the purpose are shown and discussed. Moreover, the Example described below shows an improvement point further, and does not limit this invention.

  The purpose of Experiment 1 was to determine whether a grade made with HS5CF-R12 dimensions would meet the Grade 8 criteria, even if it was forged and used. The HS5CF-R12 fastener is a commercially available grade 5 swage type fastener manufactured by Hack International, Inc., located in Waco, Texas.

  This experiment 1 includes the outer diameter (OD), hardness, swage load, tension, and preload tests of a typical grade 8 collar that has been quenched and tempered. Tested in comparison with a forged collar. Results are quantified in Table 1 below.

As shown in Table 1, the swage load is 18% lower in both colors “A” and “B” than the current general HS8CF-R12 color, and both require grade 5 as an industry standard. Meet the requirements of tension and preload. Experiment 1 revealed that color “A”, which is a forged color, has two different effects over color “B”.
1) Color “A” does not require heat treatment operations (eg, quenching / tempering or stress relief) and therefore does not experience the additional steps of cleaning or decarburizing the collar,
2) Color “A” has a higher preload margin than color “B” than the minimum value in the industry specification.

  The color “A” did not have the full high tension and preload actually equivalent to the current general grade 5 color, but its swage load was noticeable (18%) It was low. Thus, this test shows that according to the present invention, a forged collar with a small outer diameter OD and therefore a thin wall thickness exhibits optimum material properties and economically achieves a reduction in swage load (18%). I confirmed that I can do it.

  Experiment 2 stems from the desire to develop an economical method to improve the life of the installation tool and reduce the cost of making a grade 8 collar. Specifically, the purpose of this experiment was to increase the snubber load and reduce the swage load while the thinner wall forged collar maintains the same tension and preload as a typical hardened and tempered collar. Was to determine if it could be. The snubber load is a load when the collar 14 is first engaged with the pin lock grooves 26, 26a, 26b, 26c, and 26d. After this engagement position, the collar 14 is overlaid on the pins 12, 12a, 12b, 12c, 12d, so that the sheet (eg, workpieces 18, 20; 18a, 20a; 18b, 20b; 18c, 20c). Pulling out the gap is limited. If a gap remains after snubbing, clamping will be reduced because the collar extension will reduce the gap instead of stretching the pins 12, 12a, 12b, 12c, 12d.

  HSCF-R20 colors with the same operating procedure and raw material (tension 50 KSI) were divided into four groups. The HSCF-R20 color is a commercially available color that is manufactured by Hack International, Inc., located in Waco, Texas.

  Group 1 was a control group and was treated by a general method (for example, quenching and tempering). The color outer diameter OD was 25.63 mm (1.009 inches). Group 2 was forged and the collar outer diameter OD was reduced to 25.40 mm (1.000 inches). Group 3 was forged and the outer diameter OD of the collar was reduced to 25.27 mm (0.995 inch). Group 4 was forged and the collar outer diameter OD was reduced to 25.14 mm (0.990 inch).

  All colors were shot blasted and waxed to have the same surface quality and lubricity. In addition, because the same installation tool and the same test instrument, the same pin work procedure was used in all tests. Three tests were performed with each group assigned a snubbing load, swaging load, preload and tension category. To simplify the reporting, only the average value of the test is reported in Table 2 herein.

  The tolerance range of the color outer diameter OD for a typical collar is 25.70 mm (1.012 inches) to 25.55 mm (1.006 inches). Using the same tolerance range for the forged collar, the allowable collar outer OD range is approximately 25.43 mm (1.001) inches to 25.27 mm (0.995 inches). As shown in Table 2, the values of the outer diameter OD in Table 2 range from about 25.14 mm (0.990 inches) to 25.63 mm (1.009 inches), and these values are the minimum and maximum values. It can be regarded as a value. Thus, the average value of 25.40 mm (1.000 inch) and 25.27 mm (0.995 inch) can be directly compared to the nominal value of 25.63 mm (1.009 inch).

As shown in Table 2, the quantified results indicate that the forged and uncolored collar presents the following points as an advantage over the general quenched and tempered collar.
1. Increased mechanical strength snubbing load is about 44% greater, swage loading is about 11% lower, and tensile strength and preload are increased by about 5%. The preload is about 7% larger than the industry standard minimum for both types of collars, but using a forged collar improves the tensile strength from about 3% above the standard minimum to about 9% above the standard. Is done. It is a very important effect that the forged collar reduces the installed tool pressure by about 10% to 20%, resulting in reduced tool wear resulting in smaller and lighter tools that are easier to use.
2. Improved quality If the color is not quenched and tempered, the problem of hardened layer and decarburization is eliminated. Furthermore, the consistency of hardness remains the same because the forged collar has a hardness range of about 10 Rb. Also, when the hardness approaches Rb68, which is the minimum value of the grade specification, some of the tempered and tempered collars may not meet the tension requirements. This is not a problem for the exemplary forged collar with increased hardness.
3. Cost reduction By eliminating the heat treatment and associated blast cleaning steps, the cost of producing the forged collar is reduced. In addition, the cost of the color raw material is an exemplary forging because the annealed AISI 1010 steel wire commonly used to make the collar is work hardened substantially as the annealed AISI 1010 steel wire. This can be reduced by replacing it with hot rolled AISI 1006 wire that can be used to manufacture the collar. The forged collar may be made from low carbon steel that has not been annealed or has been annealed. This is also not annealed and is therefore less expensive.
4). Lead Time Reduction By omitting the heat treatment and associated inspection, about 2-3 days of the time typically required to produce a collar can be reduced.

  Therefore, the results of Experiment 2 further supported the advantage of using the forged collar in the present invention. Furthermore, when viewed in conjunction with Experiment 1, the ability of the fasteners and collars of the present invention to reduce wear of installed tool parts (e.g., anvils and thimbles) and extend tool life becomes apparent. Although an exemplary forged collar is stiffer, anvil wear was expected to increase, but it has been discovered that the anvil wear reduces the outer diameter OD of the exemplary collar 14. By reducing the wall thickness t, it did not change significantly in practice, and the thimbles had a longer service life by reducing the required tool pressure.

  With regard to the results of Experiment 1 and Experiment 2, Experiment 3 further tested the effect of increasing the collar hardness while reducing the wall thickness of the collar and sought to find the optimal balance between high strength and low swage load. Clearance drawing results in lower results than a clamp that is optimal for coupling. However, as Experiment 2 demonstrates, increasing the hardness of the collar also increases the swaging force required to install the collar. Further, by reducing the wall thickness of the collar, the swaging force is disproportionately reduced compared to the snubbing (gap pulling) load. Therefore, combining the findings of the two previous experiments, this experiment was designed to maintain the tension and preload unchanged and increase the life of the installation tool by increasing the snubbing load while reducing the swage load. The aim was to overcome the limitations of conventional fastener designs by balancing the increase in hardness with the decrease in collar wall thickness. The experiment also changed the above to change the general pin or installation tool to make the switch to the new color expected in the future as simple and cost-effective as possible. The goal is to achieve without.

  For consistency, the same color procedure was used during the test. The wall thickness of the collar was reduced by machining the outer diameter OD of the collar by 0.254 mm (0.010 inch). Snubbing load, swaging load, discharge load, preload, and tensile strength were examined in detail for optimum wall thickness. The most consistent way of significantly increasing the hardness of the collar is to leave the collar forged, as learned from Examples 1 and 2, which increases the hardness by about 20-25 Rb points in net. . Once the optimum color wall thickness was determined, the same test was made to compare the pin of the type already described herein in connection with US Pat. No. 6,497,024 to a common pin. The type of pin associated with U.S. Pat. No. 6,497,024 was heat treated to the same hardness and pin breakage as a typical pin. This was done to determine the effect of the lock groove shape. All tests were performed on production test equipment using a general test procedure.

  Since there was no significant deviation between the tests, only the average of the three tests is reported for each condition to simplify the reporting. Table 3 shows the results when an exemplary small wall thickness collar is used with common thread shapes.

  As can be calculated from Table 3, the forged collar with an outer diameter OD of 24.77 mm (0.975 inches) is calculated to have the same clamping force and tension values as the current general collar, The snubber load increases by about 54% and the swage load decreases by about 6%. This result further supports the nature of the fastener in the present invention and the nature of the forged, thin wall thickness, low swage load collar.

  Snubbing, clamping, and tension data for this group of common locking grooves (eg, of the type discussed with reference to FIGS. 7 and 7A of US Pat. No. 6,497,024) are the first group in Table 3. Prove the validity of the data. The swage load was about 1,300 pounds lower than expected, or about 12% instead of 6% on the original. There was no significant difference in the value derived from the thread shape of the lock groove. The swage load of the improved hybrid lock groove combined with a hard and thin walled forged collar is significantly higher than the swage load in the general spiral lock groove thread shape and quenched and tempered collar ( About 40%).

  In summary, this experiment can consistently increase the hardness by using a forged collar, and also increase the hoop strength with this higher hardness, thus reducing the color wall thickness. I confirmed that I can do it. Decreasing the collar outer diameter OD to 24.77 mm (0.975 inches) does not change the actual values of preload and tension, but increases the gap pull-out by about 50% and reduces the swage by about 10%. . By increasing the hardness by about 20 Rb, the calculated wear resistance of the collar is increased by about 40%, and when swaging the forged collar, there is no need to deform the pins or the swage anvil. Thus, not only the fasteners and collars therefor of the fastening system 50 of the present invention exhibit optimized physical properties, low swage loading, and economy, but the collar 14 is an improvement over the present invention. It can easily be used with a wide variety of existing fastener pins and their thread shapes as well as the hybrid thread shape 26d (FIG. 6c).

  Pins 12, 12a, 12b, 12c, 12d (FIGS. 1-3, 6B, 6C, and 7) are not crushed by excessively swaged loads, or excessive tensile yielding or local throttling occurs. It is desirable for the collar 14 to be sufficiently hard to resist the resistance. Thus, in one embodiment of the present invention, for example, in a Grade 5 type fastener, the pins 12, 12a, 12b, 12c, 12d are AISI 1038 steel, AISI1541 steel, or the same grade with a hardness of about Rc 24-35, maximum It may be made from other equivalent materials with a tensile strength of at least 120 KSI. Typically, conventional collars for this type of fastener (Example 14 ') have an AISI 1010 carbon that needs to be heat treated to a maximum tensile strength of at least about 60 KSI with a hardness between about Rb 65-85. It was made of steel.

However, as discussed above, the exemplary collar 14 is made from, for example, AISI 1006 steel, or other suitable, annealed or unannealed low carbon steel material. AISI 1006 steel is not annealed. An unannealed steel wire, commonly referred to as “green wire”, is less expensive, thus making the manufacture of the exemplary collar 14 more economical. The pins 12, 12a, 12b, 12c, 12d have sufficient hardness to accept both the desired high tensile preload and swage load applied to the collar 14 without substantially yielding. In addition, the collar 14, such as the collar discussed in US Pat. No. 6,497,024, can be coated with a water-soluble polyethylene wax or a conventional lubricant such as cetyl alcohol. The collar 14 can be galvanized. This helps to maintain the swage load at the desired low level and minimize wear of the swage cavities 112, 212, 312, 412. Therefore, as shown in Examples 1 to 3, the shank 61 (FIG. 5) of the collar 14 has a sufficient wall thickness t and therefore a sufficient volume so that a sufficient color material is elongated in the axial direction. However, at the same time, the pin shoulder 60 (FIG. 1) and the collar shoulder formed in the swage are substantially fully engaged when the tensile load on the joint reaches the design tensile load. It should be strong enough to maintain the wet state. In so doing, the wall thickness t (FIG. 5) required by the exemplary collar shank 61 is slightly increased for fasteners with a large diameter and slightly decreased for fasteners with a small diameter, and also exhibits the advantages discovered in the present invention. And is thinner than known prior art collars of equal size and grade. Further, Table 4 shows a conventional hardened and tempered collar 14 ′ and a forged collar 14 of the present invention, conventional grade 5 and grade 8 fasteners 10, 10 a, 10 b, 10 c, 10 d, and exemplary low swage. The improvements of collar 14 are summarized in a comparison when used with improved grade 5 and grade 8 fasteners 10c, 10d (FIGS. 6 and 7) of load fastening system 50. FIG. Various color dimensions are shown for three different nominal fastener sizes: 12.70 mm (1/2 inch), 15.88 mm (5/8 inch) and 6.350 mm (1/4 inch). For the former two types of fasteners, the color dimensions of the existing quenched and tempered collar 14 'are shown first, and the value of the forged collar 14 of the present invention is shown indented to the right. Only the forged color valves shown for grade 5 and grade 8 fasteners are referred to as “next generation”. These fasteners use the exemplary hybrid thread shape 126 (FIG. 6C) of the present invention, discussed herein.

  As shown in FIG. 4, in the forged collar of the present invention, the ratio of the outer diameter OD to the inner diameter ID of the forged collar is roughly (i) 15.88 mm (5/8 inch), grade 5 conventional fastening 1.491 for tools, (ii) 15.88 mm (5/8 inch), 1.540 for grade 8 conventional fasteners, (iii) 15.88 mm (5/8 inches), grade 5 next generation fasteners Was 1.481, (IV) 15.88 mm (5/8 inch), and the grade 8 next generation fastener was 1.502. A suitable range of the ratio of the outer diameter to the inner diameter in the collar of the present invention is likely to be about 1.47 to 1.55, or a specific range within this range. Additional exemplary embodiments for ranges are not described for simplicity of definition. In prior art quenching and tempering collars, the ratio of outer diameter to inner diameter of the collar is approximately (i) 15.88 mm (5/8 inch), 1.509 for grade 5 fasteners, (ii) 15. 88mm (5/8 inch), 1.557 for grade 8 fasteners.

  As the swage load is reduced, the size of the installation tool (eg, 100, 200, 300 in FIGS. 1-3, respectively; see also installation tool 400 in FIGS. 7-9) can be reduced, resulting in the conventional The weight reduction is up to 40% compared to the weight of the installation tool. See, for example, US Pat. No. 6,497,024, which describes a reduction in tool weight compared to tool 148 in FIG. 7 of that specification.

  Many fasteners (e.g., 10, 10a, 10b, 10c, 10d) that can be used together with the collar 14 of the present invention have tension portions and / or pin tips that are reduced in size and / or length. In view of the fact, it would be desirable to provide a structure for gripping the pins and collar together when initially pre-assembled to the workpiece in preparation for installation. Thus, the collar may optionally include a flexible pre-assembly tab 90 (FIG. 5). See, for example, US Pat. No. 4,813,834. If an optional assembly tab 90 is used, its structure and implementation is substantially the same as that disclosed in the above-mentioned US Pat. No. '834, which is incorporated herein as if fully described by reference. The same. Briefly, the pre-assembly tab 90 is located within the countersink portion 55 of the collar 14 and has a limited length in the circumferential direction. The pre-assembled tab 90 is preferably a flexible structure, as described in the above-mentioned US Pat. No. '834, and may thus be made from a plastic material such as polyethylene. The tab 90 extends radially inward by a distance sufficient to be positioned in a locking groove such as the grooves 26, 26a, 26b, 26c, 26d. Once positioned in one lock groove in this way, the collar 14 is held on the pins 12, 12a, 12b, 12c, 12d that cooperate therewith. Tab 90 is located in countersink portion 55 at a point aligned with flange 59. Optional tab 90 facilitates movement of collar 14 onto the pin and indexing of tab 90 on the locking groove crest. It will be appreciated that the tab 90 may alternatively be located at the opposite end of the collar 14. It will also be appreciated that the collar may not use any tabs 90.

  It will also be appreciated that one or more portions of the collar 14 may have different configurations than those described herein with the figures. For example, the collar may be free of flanges (not shown), may have a smaller size flange (not shown), and / or the collar may not include countersink portions 55. . Furthermore, the collar 14 may optionally be provided with this type of countersunk portion at the opposite end of the collar (not shown). Also, as discussed in US Pat. No. 4,867,625, an optional assembly tab (eg, 90) holds the collar 14 and cooperating pins pre-assembled to the workpiece. In addition, there may be more tight and limited threads (not shown) pre-selected to the extent that some initial clamping of the workpiece is obtained. See, e.g., U.S. Patent No. '625, which is incorporated herein as if fully set forth by reference for disclosure regarding limited internal threads.

  Another means by which the low swage load fastening system 50 of the present invention reduces swage load is shown in FIG. 6C, and in particular in comparison with FIG. 6C and FIGS. 6A and 663. Specifically, as shown in FIG. 6C, a hybrid thread shape 26d is provided for the locking groove 26d of the pin 12d and is corrugated locking groove 26b and deep locking groove 26c of the embodiment of FIGS. 6A and 6B, respectively. To improve the known thread shape, such as The exemplary thread shape of FIG. 6C is defined by a unique fusion of features, including many mixed radii, which is substantially between the crest 28d, 30d and the bottom of the lock groove 26d. To bring a smooth transition. More specifically, the first crest 28d has a first radius R1, the second crest 30d has a fourth radius R4, and the two intermediate radii R2, R3 define the bottom or valley 132 of the groove 26d. The first radius R1 and the fourth radius R4 are smoothly interconnected. In this way, the hybrid thread shape 26d (FIG. 6C) improves the relatively non-smooth abrupt transition between the shallow and deep thread shapes 26b, 26c in FIGS. 6A and 6B, respectively. Specifically, the relatively shallow waveform 26b of FIG. 6A requires more radii and transitions between radii relatively discontinuously, and the deep lock groove thread shape 26c of FIG. 6B compares between radii. It moves sharply and without mixing. Further, as shown in the figure, the waveform 26b of FIG. 6A has a wide pitch 36b and a relatively shallow depth 38b, whereas the deep thread shape 26c of FIG. 6B has a relatively narrow pitch 36c. With a much greater depth 38c.

  As will be understood with respect to each of FIGS. 6A and 6B with continued reference, the relatively shallow corrugation 26b tends to overfill as the collar 14 is swaged, as previously discussed. As a result, the swage load increases disadvantageously. In contrast, as shown, the abrupt transition in the deep thread shape 26c of FIG. 6B is a fit that occurs between the locking groove 26c of the pin 12c and the collar 14 when the collar 14 is swaged. It tends to have the opposite effect that the amount is less than the desired amount.

  Referring to FIG. 6C, comparing the exemplary hybrid thread shape 26d with the thread shapes 26b and 26c of FIGS. 6A and 6B, the hybrid thread shape has a somewhat moderate pitch 36d and depth 38d. It will be understood that it has. This provides a smooth and mixed thread shape 26d in combination with the mixed radii R1, R2, R3, R4 described above, and therefore, when the collar 14 is swaged, the collar groove 62 and the lock The complementary meshing engagement with the groove 26d is promoted, thereby reducing the swage load. The advantages of the exemplary thread shape 126 can be further appreciated from the values in Table 5 below. Table 5 shows three different grade 8 15.88 mm (5/8 inch) fasteners described with respect to FIGS. 6A, 6B and 6C, each with a different thread shape 26b, 26c, 26d. Figure 7 summarizes a non-limiting comparative example of the value of a fastener having pins 12b, 12c, 12d.

  The deep lock groove thread shape described in Table 5 was developed to reduce the problems associated with flaking of the female threaded holes 204 illustrated in FIG. It has been found that increasing the depth of the lock groove 26c is effective in reducing damage to the female screw hole 204. Subsequently, it was found that the deep locking groove 26c was not necessary for the tensile mold structure 177 of the type shown in FIG. The hybrid lock groove thread profile described in Table 5 was developed for use in a tensile structure 177 of the type shown in FIG.

  As shown, hybrid lock groove thread shape 26d (FIG. 6C) has a relatively moderate depth 38d and pitch 36d compared to corrugated and deep lock groove thread shapes 26b and 26c, respectively. On the other hand, it achieves all of the aforementioned advantages, including maintaining a low swage load that is roughly equivalent to the deep locking groove 26c of FIG. 6B. It will also be appreciated that the exemplary hybrid thread shape 26d may be used in combination with the forged collar 14 described above to further reduce swage loading. For example, for the 15.88 mm (5/8 inch) grade 8 fastener of FIG. 6C and Table 5, when using the exemplary hybrid thread shape 26d of FIG. 6c with the forged collar 14 described above. The swage load can be expected to be reduced by about 11% compared to the case where the corrugated lock groove is used. Also, for the 15.88 mm (5/8 inch) grade 8 fasteners of FIG. 6C and Table 5, when using the exemplary hybrid thread shape 26d of FIG. 6c with the forging collar 14 described above. The swage load can be expected to be reduced by about 40% compared to using a spiral lock groove.

  In the forged collar of the present invention, the ratio of shear strength between the pin and the collar is approximately: (i) 1.8 for grade 8 fasteners and (ii) 1.6 for grade 5 fasteners. It turns out that. A suitable range for the ratio of shear strength between the pin and collar of the present invention would be about 1.5 to 2.1, or some other range within this range. Additional exemplary embodiments of that scope will not be described to simplify the definition. The ratio of shear strength between pin and collar in prior art hardened and tempered collars is approximately 2.5 for (i) Grade 8 fasteners and (ii) 2.2 for Grade 5 fasteners. It turns out that.

  Also, in the forged collar of the present invention, the lock groove is typically (i) a grade 8 fastener, about 40% in the deep lock groove 26c thread shape, and the spiral lock groove 26d thread shape. And (ii) in grade 5 fasteners, about 30% in the thread shape of the deep lock groove 26c and about 50% in the thread shape of the spiral lock groove 26c. I understood. It has been found that the use of deeper locking grooves in sub-fill conditions is desirable from the standpoint that the pins are accompanied by a paint finish that is applied to the pins and accumulates in the recesses of the locking grooves.

  It has also been found that the typical ratio of pitch length to lock groove depth is about 2.8 for deep lock groove threads and about 3.6 for hybrid lock groove threads. Yes. A suitable range for a typical ratio of pitch length to lock groove depth would be about 2.5-4.0, or some other range within this range. In prior art corrugated lock grooves, the typical ratio of pitch length to lock groove depth was about 4.8.

  FIGS. 7, 8 and 9 further illustrate structures in the present invention that reduce the swage load and thereby extend the useful life of the installation tool. Like the previously discussed hybrid thread shape 26d and the forged collar 14, the following low swage load structures can also be used independently or hybrid thread shape 26d (FIG. 6C) and forged as described above. Any suitable combination with one or both of the free collars 14 (FIGS. 1-3, 5, 6A, 6B and 6C) may be used.

  FIG. 7 shows a fastener 10d and installation tool 400 for securing two workpieces 18d, 20d to each other, where the fastener is substantially straight on the second end 19 of the pin 12d. A tensile structure 177 with a relatively short tensile portion 179. In addition, four sequential steps are shown for installing fastener 10d using a typical low swage load system 50 in accordance with the method of the present invention.

  The length 183 of the pulling portion 179 of the pin 12d is relatively short so that the extension or protruding distance of the pin 12d from the second end 19 is short. In fact, the protruding length 183 of the exemplary tensile portion is short, unlike the acorn-shaped tensile portion of US Pat. No. 4,299,519, which is incorporated herein by reference (see, eg, FIGS. 1-5). Thus, the tension portion 179 of the present invention is not intended to be cut after installation. However, the cutting of the pulling portion 179 can be assumed by using the breaking groove of the pin 12d or by cutting off the pulling portion 179 with a cutting tool (not shown) according to another embodiment of the present invention. This advantageously eliminates the impact load of the installation tool 400, which is attributed to a sudden break in the break groove (see, for example, break groove 40 in FIG. 1). It also eliminates pin tip debris and pin break noise. The preferred embodiment of the akon-shaped tension portion of US Pat. No. 4,299,519 suffers from these disadvantages. More specifically, for example, in a 5/8 inch, grade 8 fastener 10d, the exemplary tensile portion 179 is about 0.10 inch, or US Pat. No. 4,299,519. It protrudes less than the Akon-shaped tension part. Similarly, unlike the Aicon-shaped tensile portion of U.S. Pat. No. 4,299,519, the exemplary tensile portion 179 extends substantially straight and all of its tensile grooves 181 have a substantially equal diameter DB, the diameter DB Is smaller than the outer diameter Da of the lock portion 25d of the pin 12d as shown. As described below, the straight, smaller diameter DB configuration of the exemplary pull portion 179 facilitates better engagement by the installation tool 400 and extends the life of the tool. It is also significantly easier to manufacture than a tapered aicon-shaped configuration, for example, US Pat. No. 4,299,519, where each groove in the tensioned portion has a different diameter.

  Other improvements of the fastening system 50 of the present invention are also shown in FIGS. Specifically, a typical installation tool 400 for installing the fastener 10d is configured to complementarily engage the groove 181 of the pull portion 179 of the pin (eg, pin 12d) as described above. And a collet 402 having a tension portion 404 having a plurality of teeth 408 and an anvil member 410 having a swage cavity 412 for swaging the collar 14. The exemplary tensile portion 179 has a small diameter DB and a generally straight configuration, which can increase the cross-sectional thickness T (FIGS. 7 and 8) of the collet 402 (FIGS. 7 and 8). Specifically, the thickness T can be increased to the full difference between the diameters Da ′ and DB of the pin lock portion 25c and the tension portion 179, respectively. This makes the installation tool 400 stronger and thereby lengthens its service life. The exemplary small diameter tension portion 179 also results in less material required to manufacture the tension portion 179, for example, compared to the tension portion and lock portion 25a of the fastener 10a of FIG. Instead, the pull groove 181 of the exemplary pin pull portion 179 and the corresponding tooth 408 of the installation tool pull portion 404 can have a greater thickness, thereby removing the pull groove 181 and Scraping can be reduced. Tensile groove peeling and scrubbing are disadvantages known for many years in this type of technical field. The first few of the tapered Akon design threads of US Pat. No. 4,299,519 may be susceptible to debonding and scuffing due to their small diameter, thus reducing strength and delamination resistance.

  As mentioned above, FIG. 7 also illustrates a general installation method using the exemplary low swage load fastening system 50 of the present invention. Specifically, as shown, once the pin 12d has been inserted into the workpieces 18d, 2Od through the aligned openings 16d, 17d as shown, the collar 14 is mounted on the second end of the pin 12d. As described above, the collar may or may not be the exemplary forged collar 14 described above. Next, the collet 402 of the installation tool 400 is engaged with the pulling portion 179 of the pin 12d. An exemplary collet is a split gripper collet 402 that extends to an open position (top view of FIG. 7) and contracts to a clamped or closed position (second view from the top of FIG. 7), where the collet tension The teeth 408 of the portion 404 are complementary and substantially completely engaged with the pulling groove 181 of the pulling portion 179. The installation tool 400 is then driven to retract the collet 402 into the swage anvil 410 and close the tension portion 404 of the collet 402 so that the collet 402 pulls the pin 12d and collar 14 into the swage cavity 412 of the anvil 410. As a result, a swage load is applied radially inward to swage (draw) the collar 14 into the pin lock groove 26d. The detection rod 406 detects when the swaging operation is completed by detecting when the pin 12d is completely pulled, and accordingly, the collet 402 is released, the tension portion 179 is opened, and the collar 14 is released. Is discharged from the anvil 410 and the installation tool 400 is stopped. In this way, the exemplary installation system 50 and installation method achieves all of the advantages of pinless installation, dramatically improving fastener installation and simplifying the thimble (metal The associated drawbacks such as the high wear rotation that inevitably occurs on the ring) are avoided and the thimble is replaced by a long-life collet 402. This makes it possible to omit several other independent parts of the installation tool, such as an independent collet, a release and discharge device, an independent jaw, and a follower and spring, which are essentially one piece, ie the exemplary split gripper collet 402 can be replaced. In this way, the present invention reduces installation cycle time, cost, and known rotational complexity for engagement, provides a faster, lighter, quieter, less moving parts installation tool and is notable. Realize significant cost savings.

  It will be appreciated that other installation methods and structures may be used that are different from those described herein with the figures. For example, as described above, it is believed that a severable pin pull portion (not shown) or an inner drive pull structure (not shown) can be used without departing from the scope of the present invention. Also, the tension portion 179 is shown as having an annular tension groove 181; however, if a corresponding improvement is made to the installation tool, other thread shapes (as a non-limiting example, a helical screw It will be understood that Yama) can also be used.

  The improvement of the exemplary installation tool 400 obtained by the exemplary pin pull substructure is further understood from FIGS.

  FIG. 8 shows a portion of the pull portion 404 of an exemplary split gripper collet 402 for the installation tool 400. The tension portion 404 has an engagement end portion 405 (portion facing leftward in FIG. 8) and a plurality of teeth 408. In the example of FIG. 8, the tension portion 404 has four teeth 408. The first tooth 409 adjacent to the engagement end 405 has a first inner diameter ID1. The other tooth 408 has a second inner diameter ID2 that is smaller than ID1. By expanding the inner diameter ID1 of the first tension tooth 409, the collet design of the present invention resists the chipping of the tooth 409, as shown.

  Specifically, the top of the exemplary first tooth 409 (shown in phantom in FIG. 8) has been removed to widen the inner diameter ID1 at that location. This instead moves the main point of the load from this position to the back of the tension portion 404 (eg, to the right in FIG. 8), thereby adding to the foremost root radius r of the tooth 409. The moment is reduced, and as a result, the useful life of the collet 402 is extended. More specifically, for example, referring to the first tooth height h in the embodiment of FIG. 8, the tooth height is about 30% lower, resulting in a dramatic increase in the service life of the tool 400, previously The anterior tooth 409 ceased to function at 14,000 cycles, whereas in a grade 5 fastener having an exemplary tension portion 179 (FIG. 7), about 12,000 pounds of swage pressure was about Installation cycles increased to 24,000 cycles. As described above, the dramatic improvement is that the inner diameter ID1 is increased and the moment arm of the front tooth 409 is shortened, so that the damage form is more robust in the tension portion 404 of the collet 402 (for example, fourth from the left). Due to the movement to the tooth 408). This improvement is in addition to the extension of the tool life obtained by increasing the wall thickness t of the collet 402 described above. Further, as previously mentioned, all of these are obtained using an exemplary single piece split gripper collet 402 that requires an independent jaw, independent drain, or independent follower and spring. It is suitable for expansion and tightening. This is because the exemplary split gripper collet 402 has at least one slit (not shown), which is from the position where the gripper collet 402 is relaxed or widened (top view of FIG. 7), Allows the anvil 410 to be tightened by being pulled into the inner bore 420 (FIG. 9) of the anvil 410 to a closed or clamped position (second view from the top of FIG. 7). Apply a radially inward force to close the collet tension portion 404. However, other known or suitable alternative collet designs (not shown) having, for example, a non-limiting example of an independent tightenable jaw (not shown) can be used, for example, in the pin tension portion 179 (FIG. 7). It will be understood that it can be used to engage and pull.

  FIG. 9 illustrates yet another advancement of an exemplary low swage load fastening system 50.

  Specifically, the exemplary swage anvil 410 has a swage cavity 412 that includes a collar 14 (FIG. 7), a swage land 416, and an inner bore 420, as shown. Has an enlarged inlet portion 414 to assist in initial mating. The swage land portion 416 has a first diameter D1, and the inner hole 420 has a second diameter D2 that is larger than the first diameter D1. Accordingly, the bore diameter D2 that spreads behind the swage land portion 416 releases the compression swage load that occurs in the collar 14 (FIG. 7). This is made possible by the relatively narrow (ie, small) exemplary swage land 416 (best shown in the enlarged partial view of FIG. 9). The narrow width 418 of the swage land portion is different from the case where the swage anvil 410 has a single diameter substantially continuously over the entire length L of the swage anvil 410, so that the narrow width portion 418 widens from the narrow land portion toward the inner diameter D 2. Define a small swage area. The enlarged diameter D2 of the inner bore 420 of the exemplary anvil 410 also provides a space to accommodate the thicker and hence stronger wall thickness T (FIGS. 7 and 8) of the collet 402, thereby allowing the tool The service life is further extended. Further, the length L of the improved anvil 410 of the present invention may be shorter than, for example, the anvil 110 of FIG. Thus, the low swage load fastening system 50 of the present invention reduces the number of parts in the tool, reduces the weight of the tool, reduces the swage load required by the tool, reduces the cost of manufacturing the tool, Extending the expected lifetime has resulted in many improvements to the installation tool 400.

  With particular reference to FIGS. 6A, 6B and 6C, the interaction between the collar and the bolt will be described. When the collar first tries to pull the bolt to the preload, the collar is not strong enough so that the first bolt crest shears the collar, creates a void and rolls up the color material in front of the bolt crest. The same thing happens in the second bolt crest, but to a lesser degree. Eventually enough collar material will engage the bolt and no voids or windings will occur. This occurs faster because of the higher shear strength in the hard forged collar than the quenched and tempered collar. A stiffer collar will pull the bolt faster and generate a greater preload.

  FIG. 10 is a cross-sectional view of an improved fastener pin tension portion and installation tool shape in one embodiment of the present invention when swaging a fastener collar using the improved pin tension portion with a different collet. The four sequential installation steps are shown. The system shown here is the same as in FIG. 11, similar to FIG. 8, is a cross-sectional view of the end of a different collet for the installation tool of FIG. 10.

  Figures 10 and 11 disclose a low swage load fastening system for a swage type fastener configured to secure a plurality of workpieces together. The swage type fastener includes a single pin member having an elongated pin shank suitable for placement within an aligned opening in the workpiece. One end of the pin member terminates at an enlarged head adapted to engage one surface of the plurality of workpieces, and the other end is opposite the opposite side of the plurality of workpieces Terminate with a grooved portion suitable for extending past the surface of the substrate.

  This grooved portion has a plurality of locking grooves defined by a pin groove extending in the circumferential direction and a pin shoulder terminating at a pink rest (pin top) in relation to the pin groove. It has.

  The installation tool includes an anvil member 410 having a swage cavity. The forged collar 14 is provided with a generally straight color shank, and this collar shank depends on the relative axial force or swage load applied between the pin member and the forged collar by the installation tool. Suitable for swaging into the lock groove.

  The joint to be fastened is also determined depending on how much load is desired as the clamp load applied to the workpieces fixed to each other. The swaging cavity of the installation tool is configured to engage the collar shank and swage it radially inward. The forged collar has a collar groove and a pin shoulder that meshes with the pin groove and the pin shoulder when swaged. The pin member and the forged collar are different materials having different magnitudes of maximum shear stress such that yielding of the pin member is substantially avoided when swaging the collar on the pin member. Consists of.

  The collet 600 has a protruding portion 602 from the collet so that the length 604 of the tensile portion extends in the direction of the collar 14, thereby increasing the contact area with the anvil 410. Increasing the length of the tension increases the contact area with the anvil, thereby reducing pressure and scuffing. This also allows the pull to have a bite angle as it returns through the smaller anvil hole.

  The forged collar does not require heat treatment and the wall thickness of the generally straight color shank of the forged collar is relatively thin, reducing the swage load required for the forged collar.

  The protruding portion 602 forms an annular plane 606 that is adjacent to the front of the tip thread 608 of the collet 600. In front of the plane 606, there is an annular front inclined surface 610. There is also a second plane 612 and an inclined flat surface 614 that returns to the line of the intersection region 616 with the outer diameter of the collet 600. The shear strength of the last bolt crest is increased by not reducing the outer diameter of the headed blank at the bolt end.

  The end 618 of the pull 620 is not reduced to a diameter position that coincides with the bottom 622 of the groove 624. This increases the shear strength of the end tensile crest 626 of the tensile portion 620. The tension tooth shears the bolt thread at line 636.

  The tension final tension crest 626 has a contour 628 that matches the expanded tension radius 630 of the final tooth 622 of the collet 600.

  Further, the first teeth 632 having a short tensile portion increase the thickness 634, so that the chipping is reduced.

  As described above, the present invention provides a low swage load fastening system and method, including a forged collar, a hybrid lock groove thread shape, an improved pin pull, and various installation tools. There are many improvements in fasteners and installation tools, including improvements, all these improvements reduce swage load, either independently or in any appropriate combination, and swage type fasteners To improve the installation of

  Although specific embodiments of the present invention have been described in detail, it is understood that those skilled in the art can develop various variations and modifications to these details in view of the overall teachings of the present disclosure. Will be done. Accordingly, the specific configuration disclosed is merely an example, and the present invention is not limited in scope thereto, and the present invention has a sufficient spread over the scope of the claims and the equivalents thereof. It is.

10 Fastener 12 Pin member 14 Low swage load collar 15 Shank 16, 17 Hole 18, 20 Work piece 22 Head 24 Shank portion 25 Lock shank portion 26 Lock groove (thread shape)
40 breaking groove 41 pulling shank portion 42 annular land 44 pulling groove 50 fastening system 71 crest 90 tab 100, 200, 300, 400 installation tool 102 nose assembly 104 jaw 106 tubular collet assembly 108 anvil housing 110, 210, 310, 410 swazien Building part 112,212,312,412 Swage cavity 114 Conical track 116 Jaw driven assembly 179 Pin pulling part 402,600 Collet 404 Collet pulling part 406 Detection rod 408 Teeth 416 Swage land part 606 Annular plane 610 Forward inclined surface 612 First Two flat surfaces 614 Inclined flat surface 616 Crossing region 618 End portion 620 Tensile portion 622 Bottom 624 Groove 626 End portion tensile crest

Claims (6)

In fasteners,
A pin member having an elongated pin shank suitable for placement in an opening aligned with a plurality of workpieces, wherein the first end of the pin member engages a surface on one side of the workpiece. Terminates at the head and the second end terminates in a grooved portion extending past the opposite surface on the opposite side of the workpiece, the grooved portion extending in the circumferential direction A pin member having a locking portion having a plurality of locking grooves defined by a pin groove and a pin shoulder terminating in a pink rest relative to the pin groove;
A substantially straight tension portion extending from the second end of the pin member and comprising a plurality of tension grooves, the tension portion having an outer diameter that is smaller than the outer diameter of the lock portion of the pin member When,
A collar comprising a generally straight collar shank, said collar shank adapted to swage the lock groove of the pin member in response to relative axial force applied to said pull portion of the pin member, Thus, the collar is configured to apply a desired amount of clamping load to the workpiece, the collar having a collar groove and a collar shoulder that meshes with the pin groove and the pin shoulder when swaged. ,
The pin member and the collar are configured to have different magnitudes of maximum shear stress so that yielding of the pin member is substantially avoided when swaging the collar;
The locking groove of the pin member has a hybrid thread shape defined by a number of radii for each of the pin groove, the pin shoulder and the pink groove of the locking groove, and the radius is between the radii. Various sizes are mixed to make a substantially smooth transition, so that when the collar is swaged, the collar groove and collar shoulder and the locking groove interlock with each other. Promotes and reduces the swaging load required to swage the collar,
The tension part of the pin member has a length shorter than the length of the lock part of the pin member, and the protruding length of the tension part from the second end of the pin member is relatively short; Further, the tension portion is configured to remain at the second end portion of the pin member after installation of the fastener.
Fasteners.   The fastener according to claim 1, wherein all of the pulling grooves in the pulling portion of the pin member have the same diameter. In fasteners,
A pin member having an elongated pin shank suitable for placement in an opening aligned with a plurality of workpieces, wherein the first end of the pin member engages a surface on one side of the workpiece. Terminates at the head and the second end terminates in a grooved portion extending past the opposite surface on the opposite side of the workpiece, the grooved portion extending in the circumferential direction A pin member having a locking portion having a plurality of locking grooves defined by a pin groove and a pin shoulder terminating in a pink rest relative to the pin groove;
A collar having a generally straight collar shank, the collar shank being suitable for swaging in the locking groove of the pin member in response to a swage load applied between the pin member and the collar, A collar configured to apply a desired amount of clamping load to the workpiece, the collar having a collar groove and a collar shoulder that operate in conjunction with the pin groove and the pin shoulder when swaged;
The pin member and the collar are configured to have different maximum shear stresses such that yielding of the pin member is substantially avoided when swaging the collar;
The locking groove of the pin member has a hybrid thread shape defined by a number of radii for each of the pin groove, the pin shoulder and the pink groove of the locking groove, and the radius is between the radii. Various sizes are mixed to make a substantially smooth transition, so that when the collar is swaged, it promotes complementary engagement of the collar groove and the locking groove, In addition, the swage load required to swage the collar is reduced,
Each said locking groove has a pitch length and depth, wherein the ratio of pitch length to depth is about 2.5 to 4;
Fasteners.   The crest of each pin groove includes a first crest and a second crest, a distance between the first crest and the second crest defines a pitch of the lock groove, and the radius is first and second. , Third, and fourth radii, and the second radius and the third radius define a bottom portion of the pin groove, the first, second, third, and fourth radii therebetween 4. Fastener according to claim 3, wherein the fastener is mixed so as to transition substantially smoothly as described above. The fastener of claim 4, wherein the hybrid thread shape defined by the blended radius is selected from the group consisting of an annular hybrid thread shape, a helical hybrid thread shape, and a corrugated hybrid thread shape. .   The fastener of claim 3, wherein the ratio of shear strength between the pin and the collar is between about 1.5 and 2.1.

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