Reduced weight aircraft collar and method of making same

Abstract

A nut or collar formed from a high-speed cold working process wherein the nut or collar has portions of the material forming the nut or collar removed therefrom thereby maintaining the strength of the nut or collar. The removed material is preferably in the form of curved scallops at the base of the collar or nut at spaced locations thereon formed during the cold working process.

Description

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates to aircraft fasteners, and particularly to nuts or collars that threadably mate to pins and the method of making the same.

[0004] 2. Related Art

[0005] In our U.S. patent application Ser. No. 09/552,474, filed Apr. 18, 2000, and commonly assigned, we disclose a fastener having a pin with a specific thread and a plurality of nuts adapted to threadably mate with the pin. One of these nuts is disclosed as having a plurality of generally rectangular cut-out areas spaced about the outside periphery of the nut. The nut has a threaded bore adapted to mate with the modified thread of the pin.

[0006] The cut-out areas on the nut reduce the overall weight of the nut. This reduction will amount to a great savings in overall aircraft weight, since so many nuts are required on the aircraft. As in our pending application Ser. No. 09/552,474, such savings in weight must be accomplished without compromising aircraft industry standards.

[0007] There is a need for a nut or collar having such weight savings that can be threaded to any threaded pin. Many different types of nuts or collars are used in the aircraft industry. Many of these collars or nuts are designed for single-use applications and are used to fasten aircraft panels to the aircraft structure. This is shown in FIGS. 1 and 8 of our pending application Ser. No. 09/552,474 and described therein. However, existing nuts or collars used in the aircraft industry do not incorporate means for removing the nuts or collars from the installation if necessary. For example, existing nuts or collars that incorporate a hex portion for installation have such hex portion broken off or removed during installation. This allows no way by which to remove the collar or nut.

[0008] This need to reduce weight and yet still satisfy aircraft industry standards is a key element in the design of any such nut or collar. There is also a need for removing such a nut or collar from the installation if necessary.

INVENTION SUMMARY

[0009] It is an object of this invention to provide a threaded nut or collar for use in the aircraft industry that can be fastened to any conventional pin or to the threaded pin in our co-pending application Ser. No. 09/552,474, the teachings of which are incorporated herein by reference, which has substantially reduced weight, yet still satisfies aircraft industry standards.

[0010] It is a further object of this invention to provide a nut or collar having portions of the material forming the nut or collar removed therefrom, using a high-speed cold working process, thereby maintaining the strength of the nut or collar.

[0011] It is still further an object of this invention to provide a method of making such nuts or collars.

[0012] It is still another object of this invention to provide a method of using such portions to install or such nuts or collars to an installment or remove such nuts or collars from the installation.

[0013] These and other objects are preferably accomplished by forming curved scallops at the base of the collar or nut at spaced locations during a cold-working process on the nut or collar. Further weight saving may be made between the shank of the nut or collar and the base of the nut or collar by reducing the diameter of the nut or collar.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is perspective view of a collar in accordance with the teachings of the invention;

[0015] FIG. 2 is a detailed view of one of the cut-out areas alone of the collar of FIG. 1;

[0016] FIG. 3 is a cross-sectional view of the collar of FIGS. 1 and 2;

[0017] FIG. 4 is a view taken along lines 4-4 of FIG. 3;

[0018] FIG. 5 is a detailed view of the breakaway groove of the nut or collar of FIGS. 1 to 4;

[0019] FIG. 6 is a perspective view of the nut or collar of FIG. 3 after breakoff of the hex shank portion of the nut or collar;

[0020] FIG. 7 is a view similar to FIG. 3 of a modified nut or collar;

[0021] FIG. 8 is an elevational view of a modification of a nut or collar in accordance with the teachings of the invention;

[0022] FIG. 9 is a cross-sectional view of the nut or collar of FIG. 8;

[0023] FIG. 10 is a perspective view of a nut or collar similar to the nut or collar of FIGS. 8 and 9 having a smooth bore interior;

[0024] FIG. 11 is a perspective view of prior art hex shaped bar stock;

[0025] FIG. 12 is a cross-sectional view of a nut or collar, such as the nut or collar of FIG. 1, formed by a conventional process;

[0026] FIG. 13 is a cross-sectional view of a nut or collar, such as the nut or collar of FIG. 1, formed by high speed cold forming process of the invention illustrating grain flow;

[0027] FIG. 14 is a cross-sectional view of the nut or collar of FIG. 13 illustrating the final configuration; and

[0028] FIG. 15 is a view similar to FIG. 10 illustrating another version of the nut or collar of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Referring now to FIG. 1 of the application, an aircraft nut or collar 10 is shown. Nut or collar 10 has a base portion 11, an integral intermediate generally cylindrical portion 12, and a forward shank portion 13 integral with cylindrical portion 12 and separated therefrom by breakaway groove 14 (see FIGS. 3 and 5).

[0030] Nut or collar 10 includes a throughbore 15 which is preferably threaded and adapted to threadably mate with the threaded shank of an aircraft pin. This preferred thread may be conventional, to thereby mate with the thread of a conventional aircraft pin. Alternatively, the inner threaded bore 15 of nut or collar 10 may have a thread adapted to mate with the thread of a pin as described and claimed in our co-pending application Ser. No. 09/552,474, the teachings of which are incorporated by reference. Further, the throughbore 15 may be smooth and interlock with the annular ridges or threads of a pin.

[0031] As seen in FIGS. 1 and 3, the cylindrical portion 12 tapers to base portion 11 which is greater in outer diameter than intermediate portion 12.

[0032] A plurality of spaced scalloped portions 18, such as 6 such portions (see FIG. 4), are provided cut-out of base portion 11 of nut or collar 10, generally equally spaced therearound. One of the scalloped portions 18 is shown in detail in FIG. 2. Each scalloped portion 18 thus has an upper curved arch portion 19 that curves downwardly on each side thereof (sides 20 and 21, respectively) away from arch portion 19 to the bottom thereof (adjacent mid-portion 12). It can be seen that the spacing between terminal ends 22 and 23 of sides 20 and 21, respectively, is equal to the spacing between sides 20 and 21 at their greatest width.

[0033] The nut or collar 10 is preferably of metal, such as stainless steel, and is formed in any suitable manner. The scalloped portions 18 are formed in the metallic material during a high-speed cold forming process.

[0034] The carving out of the scalloped portions 18 removes weight while retaining the structural integrity of the nut or collar using the high-speed cold forming process. This method results in a nut or collar 10 that is about 18% to 25% lighter in weight than currently-used aircraft nuts or collars, while at the same time meeting aircraft industry standards.

[0035] The scalloped portions 18 about the base portion 11 of the nut or collar 10 are arranged to maximize the aforementioned weight savings and minimize the impact of the structural integrity of the nut or collar due to the weight reduction.

[0036] Further weight reduction may be made by reducing the outer diameter of the section 12′ (FIG. 7.—like numerals referring to like parts of the nut or collar 10 of FIG. 3). Also, in this embodiment, throughbore 15′ may be smooth instead of threaded, as shown.

[0037] The outer hex configuration of nut or collar 10 assists in driving the same onto the mating thread of a pin, using a suitable installation tool. By using a high-speed cold forming process, high volume production of such nuts or collars is attained with improved metallurgical characteristics imparted to the nuts or collars for strength purposes.

[0038] The large curved surfaces and radiused corners of the scalloped portions 18 reduce stress concentrations and provide an efficient load path. This has been evidenced in testing of nuts or collars 10 formed using the techniques disclosed herein.

[0039] As seen in FIG. 5, the breakaway groove 14 enables the hex-shaped shank portion 13 to break off during installation of nut or collar 10 (broken off at area 100 in FIG. 6). That is, as the collar 10 is installed and bottoms out against the application, the shank portion 13 breaks off at the correct torque. The torque value relates to the tension preload of the collar and pin assembly.

[0040] Any suitable dimensions may be used. For a ¼″ fastener diameter, the diameter of the breakoff groove 14 may be about {fraction (5/16)} of an inch, and the sides surrounding the groove 14 may be at an angle a of about 30° (see FIG. 5). For a ¼″ thread diameter of a fastener, each scalloped portion 18 may be about 0.125 inches long, about 0.020 inches deep and about 0.125 inches at their widest part. As seen in FIG. 4, the spacing c between portions 18a and 18c (separated by portion 18b) may be about 0.340 inches. The angle between the centerline of adjacent portions, such as portions 18d and 18e, may be about 60° (see angle d in FIG. 4).

[0041] As seen in FIG. 8, further weight reduction can be made by eliminating intermediate portion 12 as seen in nut or collar 60 in FIG. 8. Nut or collar 60 has a hex portion 61 and an integral base portion 62 having a first tapered portion 63 leading from portion 61 to a cylindrical portion 64, greater in outer diameter than portion 61. A plurality of scalloped portions 65, such as 6, are spaced about the outer periphery of portion 64 identical to the scalloped portions 18 of FIG. 1. These scalloped portions 65 can also be used to drive nut or collar 60 by grasping the same manually or using a suitable tool, such as pliers or any other tool having a suitably configured nose piece, so as to grasp the nut or collar 60 at the portions 65. Thus, such portions 65 or portion 61 can be used to install or remove nut or collar 60 from its application. Such portions 65 can also be used in like manner to grasp the nut or collar 60, using any suitable tool, to remove the nut or collar 60.

[0042] As seen in FIG. 9, nut or collar 60 may be threaded on its interior threads 66 adapted to mate with a threaded bolt as heretofore discussed. Alternatively, as seen in FIG. 10, wherein like numerals refer to like parts of FIG. 8, nut or collar 67 may have a smooth or non-threaded throughbore 68 which mates and interlocks with annular ridges or threads of a suitable bolt by swaging of the collar 67 on to the threads or ridges of a bolt. Thus, the nut or collar 67 is designed to be swaged onto the mating pin or bolt. It may also be smooth walled, as at wall 72, on its outer surface. The scalloped portions 65 are thus used to install or remove the nut or collar in an installation if threaded to a threaded pin or bolt.

[0043] The nut or collars disclosed in FIGS. 1 to 10 may be formed in any suitable manner known in the prior art. For example, a hex shaped bar 69 of stainless steel or aluminum is shown in FIG. 11. Such bar may be about 0.437 inches in hex size. Normally, a nut or collar formed from a conventional process, such as nut or collar 70 in FIG. 12, (essentially identical to the nut or collar 10 of FIG. 1), would have grain flow extending in grain flow lines parallel to the longitudinal axis of nut or collar 70 as seen by line 71.

[0044] Using a conventional high-speed cold-worked process, round wire of stainless, titanium, or aluminum may be used to form nuts or collars, such as the nuts or collars disclosed in FIGS. 1 to 10, one of which, nut or collar 72, is shown in FIG. 13. Prior to forming groove 14, grain flow is along grain flow lines 73 parallel to the longitudinal axis of nut or collar 72 at the shank portion 74, intermediate portion 75, and base portion 76 terminating in enlarged terminal end 77. It is to be understood that the blank shown in FIG. 13 is the first step in the process of forming the final configuration of the nut or collar 78 shown in FIG. 14.

[0045] As can be seen in FIG. 13, the grain flow lines 79, at terminal end 77, flow or curve from lines 73 as shown. The final configuration of the nut or collar blank shown in FIG. 14 shows a groove 80, similar to groove 14, has now been formed and intermediate portion 75 may be threaded on its interior, at threads 81, (or left otherwise smoothbored, as previously discussed).

[0046] The grain flow formed on the nut or collar 78 of FIGS. 13 and 14 results in a stronger part, the material flowing into the scalloped portions 82 as seen in FIGS. 13 and 14 (portions 82 being otherwise identical to the scalloped portions, such as portion 18, as otherwise discussed).

[0047] In addition to the weight-to-strength efficiency of nut or collar 10 accomplished herein, a more effective sharing of the weight between all of the threads of the threaded throughbore 15 takes place. The reduction in material provided by scalloped portions 18 at the base portion 11 of nut or collar 10 allows adequate deflection on the nut or collar 10 to induce a moment at base portion 11. In turn, the moment induces a centrifugal deflection of the base portion 11, which consequently relieves the load concentration of the first few internal threads of nut or collar 10 and redistributes the load more evenly among the rest of the internal threads. The effect of the material removal geared for weight reduction also promotes the equal sharing of the load by all the threads of the threaded throughbore 15 of nut or collar 10.

[0048] Still another version of the nut or collar of the invention is shown in FIG. 15 wherein like numerals refer to like parts of the nut or collar of FIG. 10. Here, nut or collar 70 has a threaded throughbore 72 and a smooth walled exterior 71. It may be threaded to a threaded bolt, as heretofore discussed, and installed or removed from an installation using scalloped portions 65, as heretofore discussed.

[0049] The term “thread” as used herein includes a helical thread having spaced thread portions, or a plurality of spaced annular thread portions or ridges, each separate from the other and separated by grooves. Any suitable dimensions may be used. The threaded throughbore 15 of nut or collar 10 may be in conformance with well-known standards in the aircraft industry for conventional nuts or collars, or modified in accordance with industry standards, as disclosed in our co-pending application Ser. No. 09/552,474.

[0050] The invention disclosed herein greatly reduces the weight of the nut or collar without compromising the strength required for the particular application in the aircraft industry. All of the embodiments herein are formed by a high speed cold working process.

[0051] It can be seen that various versions of a nut or collar can be formed using the techniques of the invention all having pockets or scallops or cut-out portions formed in the nut or collar during a high speed cold working process. These versions are as follows:

[0052] 1. A round collar or nut as shown in FIG. 1. The nut or collar has internal threads and a twist off hex portion 13 and is installed (or removed) using the twist-off hex portion 13.

[0053] 2. A hex nut or collar with a threaded portion as shown in FIG. 8. This nut or collar may be installed (or removed) using either the scalloped portions 65 or the hex portion 61.

[0054] 3. A round collar or nut with an internal threaded portion as seen in FIG. 15. In this embodiment, the nut or collar is installed (or removed from an installation) using scalloped portions 65 as heretofore discussed.

[0055] 4. A round collar with a smooth throughbore as seen in FIG. 10. In this version, the nut or collar is swaged onto the threads, serrations or annular ridges or grooves of a threaded bolt. The scalloped portions 65 are used to install (or remove) this version from its installation if installed on to a threaded pin or bolt.

[0056] Thus, the nuts or collars disclosed herein allow the nut or collar to be installed using the scalloped portions or removed from the installation using the scalloped portions. The scalloped portions provide weight reduction while at the same time allow the customer the additional option of using such scalloped portions to install the nuts or collars or, if necessary, remove the nuts or collars from the installation.

[0057] Although a particular embodiment of the invention is disclosed, variations thereof may occur to an artisan, and the scope of the invention should only be limited by the scope of the appended claims.

Claims

1. A reduced weight aircraft collar comprising: a base portion having an outer periphery and a terminal end; a forward shank portion; an intermediate portion interconnecting said base portion and said shank portion; a throughbore extending through said collar; and a plurality of spaced cut-out portions extending about the outer periphery of said base portion.

2. The collar of claim 1 wherein a portion of said throughbore is threaded.

3. The collar of claim 1 wherein said cut-out portions are scalloped portions, each of said scalloped portions having an arched portion adjacent the terminal end of said base portion, with spaced side portions extending from opposite sides of said arched portions to the junction of said base portion with said intermediate portion.

4. The collar of claim 1 wherein said collar is of metal formed from a high-speed cold-worked process.

5. The collar of claim 4 wherein said collar is of stainless steel.

6. The collar of claim 3 wherein six scalloped portions are provided.

7. The collar of claim 1 wherein said intermediate portion has an outer diameter less than the outer diameter of said shank portion.

8. The collar of claim 1 wherein said base portion has a first generally cylindrical portion tapering to an enlarged circular portion at said terminal end.

9. The collar of claim 1 wherein said intermediate portion is generally cylindrical and lesser in outer diameter than said base portion.

10. The collar of claim 1 wherein a breakaway groove separates said shank portion from said intermediate portion.

11. The collar of claim 10 wherein said shank portion is hex-shaped in outer configuration.

12. The collar of claim 10 wherein said shank portion is smooth walled in outer configuration.

13. A reduced weight aircraft collar comprising: a base portion having an outer periphery and a terminal end; a shank portion integral with said base portion; a throughbore extending through said portions; and a plurality of spaced cut-out portions extending about the outer periphery of said base portion.

14. The collar of claim 13 wherein said at least one of said portions of said throughbore is threaded.

15. The collar of claim 13 wherein said shank portion is hex-shaped in outer configuration.

16. The collar of claim 13 wherein said shank portion is smooth-walled in outer configuration.

17. The collar of claim 16 wherein at least one of said portions of said throughbore is threaded.

18. The collar of claim 13 wherein said cut-out portions are scalloped portions, each of said scalloped portions having an arched portion adjacent the terminal end of said base portion, with spaced side portions extending from opposite sides of said arched portions to the junction of said base portion with said intermediate portion.

19. A method of forming a reduced weight collar having a base portion having an outer periphery and a terminal end, a forward shank portion, an intermediate portion interconnecting said base portion and said shank portion, and a throughbore extending through at least one of said portions, the method comprising the steps of: forming a plurality of spaced cut-out portions extending about the outer periphery of said base portion.

20. The method of claim 19 wherein the step of forming said spaced cut-out portions includes the step of forming scalloped portions, each having an arched portion adjacent the terminal end of said base portion, with spaced side portions extending from opposite sides of said arched portions to the junction of said base portion with said intermediate portion.

21. The method of claim 19 wherein the step of forming said portions includes the step of forming the same during a high-speed cold-working process.

22. A reduced weight aircraft collar comprising: a base portion having an outer periphery and a terminal end; a forward shank portion integral with said base portion; a throughbore extending through at least one of said portions; and a plurality of spaced cut-out portions extending about the outer periphery of said base portion.

23. The collar of claim 22 wherein said throughbore is threaded.

24. The collar of claim 22 wherein said cut-out portions are scalloped portions, each of said scalloped portions having an arched portion adjacent the terminal end of said base portion, with spaced side portions extending from opposite sides of said arched portions to the junction of said base portion with said shank portion.

25. The collar of claim 24 wherein said collar is of metal formed from a high-speed cold-working process.

26. The collar of claim 25 wherein said collar is of stainless steel.

27. The collar of claim 24 wherein six scalloped portions are provided.

28. The collar of claim 22 wherein said base portion has a first generally tapered portion tapering to an enlarged circular portion at said terminal end.

29. The collar of claim 22 wherein said shank portion is hex-shaped in outer configuration.

30. The collar of claim 22 wherein said shank portion is smooth walled in outer configuration.

31. A method of forming a reduced weight collar from a round wire comprising the steps of: cold-working said wire in a high-speed process to form the same into a collar having a base portion with an outer periphery and a terminal end, a forward shank portion, and an intermediate portion interconnecting the base portion and the shank portion with a throughbore through at least one of said portions, and a plurality of spaced cut-out portions extending about the outer periphery of said base portion, the flow of grain of the material of said collar being along lines generally parallel to the longitudinal axis of said collar, but flowing outwardly and curving about said scalloped portions at the terminal end of said base portion.

32. A method of forming a reduced weight collar from a round wire comprising the steps of: cold-working said wire in a high-speed process to draw the same into a collar having a base portion with an outer periphery and a terminal end, an integral forward shank portion with a throughbore through at least one of said portions, and a plurality of spaced cut-out portions extending about the outer periphery of said base portion, the flow of grain of the material of said collar being along lines generally parallel to the longitudinal axis of said collar, but flowing outwardly and curving about said scalloped portions at the terminal end of said base portion.

33. A method of installing a nut or collar into an installation and removing the same therefrom comprising the steps of cold working a round wire to form a nut or collar. cold-working said wire in a high-speed process to draw the same into a collar having a base portion with an outer periphery and a terminal end, an integral forward shank portion with a throughbore through at least one of said portions, and a plurality of spaced cut-out portions extending about the outer periphery of said base portion, the flow of grain of the material of said collar being along lines generally parallel to the longitudinal axis of said collar, but flowing outwardly and curving about said scalloped portions at the terminal end of said base portion.