JPH05248422A - Clamp assembly with integral anti-rotation means and method of manufacturing thereof - Google Patents

Abstract

PURPOSE: To reduce overall production and transportation cost of a clamp assembly used for fixing objects to a base material precluding possibility of losing the lock ring. CONSTITUTION: The clamp assembly 10 comprises a first threaded portion 14, a second threaded portion 16 and an integral anti-rotation means 12 between those threaded portions 14, 16. The clamp assembly 10 is produced from a cylindrical blank. First, a cup-shaped flange portion with an upward slant and a downward groove is formed between the first and second portions of the blank intended for respective threaded portions. Then, the blank is passed through a die. The flange portion is formed parallel to the axis, and serration if formed on the circumference.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastener having an integrated anti-rotation means mounted on a material. This fastener is associated with other fasteners that secure the object to the base material.

[0002]

2. Description of the Prior Art Lock rings have been used in the past to prevent loose studs and inserts used to hold objects in place from vibrations such as those generated by high performance aircraft engines. Many solutions have been proposed using.

US Pat. No. 2,577,810 to Lohsan discloses an insert having an annular locking head with serrations at one end. The insert is installed in a counterbore threaded hole formed in the base material. The expansion tool expands the lockhead, i.e. its part. The lock head is expanded radially outward so as to mesh with the serration of the base material and locked in the base material.

US Pat. No. 3,720,969 to Lohsan et al. Discloses a stud fastener assembly that is threaded at both ends. The lock ring is threaded through the stud fastener after being threaded at one end and before being threaded at the other end, thus retaining the lock ring in the fastener assembly.

US Pat. No. 4,568,228 to Lohsan discloses a fastener with an additional locking ring. The fastener is manufactured with a lock ring attached to it, the lock ring being attached to the fastener by a metal tab or metal sleet that shares the same material as the fastener. Of course, the studs, inserts and lock rings are manufactured separately, but the separate lock rings are interlocked during insert / stud manufacture to prevent loss.

A further problem with connecting separate lock rings is that they increase the associated costs during the stud and insert manufacturing process, as described in US Pat. No. 4,568,228.

Therefore, it is desirable to form a lock ring in the fastener assembly as part of the stud / insert manufacturing process.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a method of forming a fastener having an integral anti-rotation means that functions as a conventional lock ring. The cylindrical blank is first formed to have an inclined bowl-shaped flange portion. The blank is then forced through the die with a force on the flange portion in a position substantially parallel to the longitudinal axis of the blank. At the same time, serrations are formed to form anti-rotation means. After the heat treatment, threads are formed on the blank, and the blank is subjected to coating treatment or plating treatment by a known method. The length of the means is longer than the length of the counterbore of the corresponding base material by a predetermined length. The fastener is then screwed into the hole in the blank until the shoulder of the means abuts the counterbore. The drive tool exerts a downward force on the fastener to crimp the knurled portion of the anti-rotation means and press it against the base material. Thus, the fastener resists rotational or torsional forces.

[0009]

Thus, the present invention provides a method of forming an insert or stud with an integral means that acts as a lock ring, thereby reducing the overall manufacturing and shipping costs of the fastener assembly. At the same time, it eliminates the need to hold a separate lock ring.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to help understanding of other objects and features of the present invention, the following description will be added with reference to the accompanying drawings.

The perspective view of FIG. 1 shows a novel fastener assembly 10 according to the present invention, in particular a stud with integrally formed anti-rotation means 12. The stud 10 has a first threaded portion 14, a second threaded portion 16, means 12 sandwiched between the portions 14 and 16, preferably the portion 16 is longer than the portion 14.

As shown by A-C in FIG. 2, the head-side blank 20 is formed by using a known method.
Preferably, the blank 20 is formed from a stainless steel bar (wire) cut into a predetermined length. The blank 20 includes a first portion 22 and a second portion 24, a tip portion 2
5, 27, and a flange portion 26 formed in a substantially inclined bowl shape. Both the land and the flange portion 26 are formed by cold head working means. Other methods such as threading means may be used, but cold head machining is preferred because it requires less material. The outwardly extending portion 26 is angled relative to the longitudinal axis 30 of the blank 20, as shown in detail and clearly in FIG. 2C. Details will be described later, but part 14,
The bowl-shaped flange portion 26 integral with 16 is utilized to form a component that performs the same function as a conventional independently formed locking ring. As used herein, the term "cup-shaped" refers to a cylindrical disc member with upwardly extending walls such that a substantial portion inside the flange is hollow.

The specific dimensions of the head-machined blank shown in FIG. 2A are as follows (unit is inch). A = 0.770 B = 1.350 C = 0.380 (before serration processing or screw processing) D = 0.2207 to 0.2217 E = 0.2260 to 0.2270 α = 45 °

FIG. 2C shows details of the bowl-shaped flange portion 26, the specific dimensions of which are as follows. R = 0.042 S = 0.020 T = 0.015 (radius) W = 0.010 (radius)

The flange angle typically ranges from 0 ° to 30 ° and is selected to match the angle of the base material counterbore.
This will automatically place it at a predetermined height above the surface of the base material before installation.

3A and 3B show the next step of the method of the present invention. In particular, the blank 20 is passed through a second die and is placed in a bowl where the outer peripheral cylindrical cup, i.e. the shell, is substantially parallel to the axis 30 of the blank 20 (if α is not 0 °). The flange portion 26 is molded. Further, as shown, serrations 32 are formed on the outer peripheral surface of portion 26, thus forming anti-rotation means 12. Next, a thread is formed on the portion 14 by rolling. The portion 16 is then threaded as close to the shoulder 34 as possible, as shown in FIG. The heat treatment and cleaning process performed before rolling and the cleaning, finishing, and / or plating process performed after rolling are the same as conventional ones, and therefore description thereof is omitted here. The fastener 10 shown in FIGS. 1 and 3A (the stud being illustrated) was formed in accordance with the present invention and is a molded portion corresponding to a standard locking ring, ie, an anti-rotation means. It has twelve. In the conventional lock ring, the anti-rotation means 12 is a separate body, but the lock ring of the present invention is different from the conventional one in that it is integrated with other parts of the stud. Further, the anti-rotation means 12 has a deep annular channel or groove 37. Conventional lock rings are solid (except for holes that allow the lock ring to move over inserts or studs) and require more metal material for manufacture.

FIG. 5 shows the completed stud of FIG. 4 installed on the base material 40. The length of the lock ring portion of the stud is longer than the length of the counterbore 42 formed on the base material 40 by a predetermined length. First, the stud
Until the shoulder 34 of the lock ring abuts the counterbore 42,
It is screwed into the base material hole. A drive tool 44 (shown in FIG. 6) with an integral cylindrical portion 46 is inserted into the stud so that the portion 46 contacts the cylindrical portion of the anti-rotation means 12. A downward force is applied to squeeze (cage) the cylindrical portion of the anti-rotation means 12 and the serrations are pressed around the base material of the counterbore 42, as shown in FIG. Thus, the fastener can withstand rotational forces (torsion).

As described above, the present invention provides an improved insert and stud integrally formed with a means for functioning as a lock ring to reduce manufacturing costs. More importantly, the inconvenience of disposing a separate formed locking ring and fitting it to its associated insert or stud can be eliminated and handling costs reduced.

Although the present invention has been described with reference to the preferred embodiments, it is needless to say that various modifications and equivalent structural changes can be made without departing from the scope of the present invention. Moreover, various modifications can be made to suit a particular situation without departing from its essence.

[Brief description of drawings]

FIG. 1 is a perspective view of a novel stud type fastener according to the present invention.

FIG. 2 shows a process for manufacturing the fastener assembly of the present invention, where A is a partial sectional view of a stud, B is a top view thereof, and C is an enlarged sectional view of a flange portion.

FIG. 3 shows a process for manufacturing the binding assembly of the present invention, where A is a partial sectional view of the stud and B is a top view thereof.

FIG. 4 is a partial cross-sectional view showing a stud type fastener assembly of the present invention.

FIG. 5 is a cross-sectional view when a stud of the present invention is installed on a base material.

FIG. 6 is a sectional view showing an installed state after the anti-rotation means is caulked in the base material and a tool therefor.

[Explanation of symbols]

 10 Fastener Assembly 12 Anti-Rotation Means 14 First Threaded Part 16 Second Threaded Part 20 Blank 22 First Part of Blank 24 Second Part of Blank 26 Flange Part 30 Shaft 32 Serration 34 Mold Part 37 Groove 40 Base Material 42 End Guri 44 Drive Tool

Claims (5)

[Claims] 1. A method of manufacturing a fastener assembly with integral anti-rotation means, the method comprising forming a cylindrical body of a predetermined length with a longitudinal axis, the length of said body comprising: Forming a bowl-shaped flange portion at a predetermined position along the direction, forming serrations on the outer peripheral surface of the flange portion, and forming an outer thread on the first portion of the cylindrical body below the flange portion. A method consisting of. 2. The method of claim 1, further comprising forming an outer thread on a second portion of the cylindrical blank above the flange portion. 3. The method of claim 1, wherein the flange portion extends outward at an angle to the longitudinal axis. 4. The method of claim 3, wherein the flange portion is biased in a position substantially parallel to the longitudinal axis when the serration is formed. 5. A fastener assembly for connecting a base material having a screw hole and a counterbore formed in the screw hole, wherein the fastener assembly is screwed into the screw hole. A cylindrical body having a longitudinal axis with a first threaded portion and a bowl-shaped integral flange portion located near the first threaded portion, the flange portion having a predetermined thickness with serrations. A wall, the flange adapted to be mounted in the hole such that a bottom of the flange portion substantially abuts the counterbore, and when a downward force is applied to the counterbore. A fastener assembly, wherein the wall engages a side wall of the counterbore to expand the flange portion to prevent rotation of the fastener.