WO2001098673A1

WO2001098673A1 - Visually distinctive safety wire

Info

Publication number: WO2001098673A1
Application number: PCT/US2000/017110
Authority: WO
Inventors: Bruce Chahanovich
Original assignee: Bruce Chahanovich
Priority date: 2000-06-22
Filing date: 2000-06-22
Publication date: 2001-12-27
Also published as: AU2000258828A1

Abstract

Safety wire (20A, 20B) is provided whose differing sizes and/or compositions are visually distinguishable.

Description

TSUΆT.T.Y DISTINCTIVE SAFETY WTRF,

Technical Field

This invention relates in general to safety wire, and, more particularly, to a visually distinctive safety wire and method therefore.

Background of the Invention

Safety wire, or lock wire, is used to secure threaded parts to prevent disengagement due to vibration and the like. Common applications include fasteners, nuts, connectors and fuse caps. As best seen in Figs. 3 and 4, parts 10 which utilize safety wire 12 will have holes 14 drilled therethrough into which wire 12 is threaded. Wire 12 is then routed to prevent parts 10 from unthreading. This is usually accomplished by twisting safety wire 12 against itself and/or leading it to another safety wired part 10 or some other convenient tether point such that any loosening of the part in question would lead to a tensioning of safety wire 12 prevent further loosening. In some cases such as fuse cap installation, a single strand of safety wire leads from part to part with the ends being twisted together to form a loop. Safety wire is mandated by a number of federal agencies, particularly, the Federal Aviation Administration and the Department of Defense for securing parts nuts in aircraft assembly. There are a number of differing specifications for safety wire. For example, the Bob Martin Co. of El Monte,

California lists 14 separate specifications for safety wire in its website (www.bobmartin.thomasregister.com/olc/bobmartin/ martin2.htm). To meet these various specifications, safety wire comes in a number of differing sizes (the Bob Martin Co. lists six) and compositions (again, the Bob Martin Co. lists eleven, however, the most common compositions are either nickel alloys or stainless steel) . The sizes and/or composition are denoted by indicia 16 printed upon reels 18 upon which safety wire 12 is provided as illustrated in Fig. 1.

However, in any maintenance shop or assembly plant, such indicia 16 can become obscured by grease or dirt or become detached from reel 18. While experienced workers are able to determine the proper size and composition from appearance or feel, less experienced or hurried workers may not use the proper wire for the application at hand. In addition, the safety wire is often trimmed to the appropriate length after installation resulting in small bits and pieces falling from the cutting area. Since often the small metallic pieces will be lost in the overall metallic appearance of an aircraft or the like, these loose missing pieces are a safety hazard.

For the same reason, the small clipped ends of safety wire may not be visible to workers operating in close proximity thereto. The sharp edges of the cut wire can injure workers who contact same .

U.S. Patent No. 5,489,174 entitled "Locking System fo Threaded Fasteners" which issued on February 6, 1996 to Lesson discloses a locking system for threaded fasteners in which a ferrule may be crimped onto the locking wire. The ferrule may be color coded at the factory.

U. S. Patent No. 4,995,274 entitled "Locking Pin and Nut Combination and Method for Visual Inspection Thereof" which issued on February 26, 1991 to Kleeman shows the use of a colored cotter pin which is useful in assemblies such as aircraft. The presence of the cotter pin can be visually determined more easily by its color from a corresponding nut.

U. S. Patent No. 5,114,289 entitled "Displaced Filler Nut" which issued on May 19, 1992 to Coiffman shows a filler which will show various colors as a nut is tightened. The filler is color coded so that different colors represent different degrees of tensile strength. None of the references disclose the present invention. Thus, there is a need to provide a safety wire whose size and/or composition is easily apparent even without an appropriate label. Further, the wire should be easy to see for safety reasons.

Further objects and advantages of the invention will become apparent as the following description proceeds and the features of novelty which characterize this invention will be pointed out with particularity in the specification annexed hereto.

Brief Description of the Drawings

Fig. 1 is a side view of a reel of the prior art upon which indicia indicate the size of the wire thereon; Fig. 2 illustrates two color coded wires of the present invention; and

Figs. 3 and 4 illustrate the prior art use of safety wire .

Description of the Preferred Embodiment

The present invention is best shown in Fig. 2 as wires 20A and 20B having means for visually distinguishing sizes and/or compositions of said wire. In the preferred embodiment, wires 20A have outer surfaces which are color- coded whereby each separate size is given its own color. For example, the most commonly used sizes in aircraft assembly and maintenance are .020, .032 or .041 (See R. Alexander, "Aircraft Hardware", EAA Sport Aviation, March, 1998) . One color scheme is the use of colors red, yellow and blue for the respective sizes in wires 20A. Coloring is preferred as it will more readily be distinguished as a foreign object when small cut pieces fall from the work area. Coloring can be accomplished by painting, dyeing or by wrapping the wires.

In an alternate, the three sizes are distinguished by imprinting stripes on the wire. Again, using the common sizes, the corresponding stripes are 1, 2 or 3 stripes corresponding to the respective sizes.

In still a third embodiment, the sizes are distinguish via the use of differently colored metals as the wire or plated on the wire. For example, one system uses copper, aluminum and brass which are visually distinctive metals. Table 1 illustrates:

TABLE 1

Wire Size color 20A Stripes 2QB .020 Red or copper One .032 Yellow or aluminum Two .041 Blue or brass Three It will be understood by those skilled in the art that the actual colors or stripping system employed is quite arbitrary and the present invention is not limited to the illustrated examples. In addition, those skilled in the art will recognize that coloring wire via plating, wrapping, dyeing or painting is well known. For example, colored electrical wires are readily available off the shelf from sources such as Antona Corporation of Los Angeles, California. Although only certain embodiments have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the spirit of the invention.

Claims

What is claimed is:

1. A safety wire system having a plurality of different safety wires for securing a corresponding plurality of threaded parts from unintentional disengagement, the system comprising: each one of the plurality of different safety wires having an outer surface having a means for visually distinguishing the one of the plurality of different safety wires from all of the other of the plurality of different safety wires.

2. The safety wire system of claim 1 wherein the visually distinguishing means comprises color coding.

3. The safety wire system of claim 1 wherein the visually distinguishing means comprises imprinting striping on the safety wires .

. The safety wire system of claim 1 wherein the visually distinguishing means comprises the use of differing metals on each of the plurality of differently sized safety wires.

5. A method for a safety wire system having a plurality of different safety wires for securing a corresponding plurality of threaded parts from unintentional disengagement, the method comprising visually distinguishing each one of the plurality of different safety wires from all of the others of the plurality of different safety wires.

6. The method of claim 5 wherein the step of visually distinguishing comprises color coding each one of the plurality of different safety wires.

7. The method of claim 5 wherein the step of visually distinguishing comprises imprinting striping on each on of the plurality of different safety wires.

8. The method of claim 5 wherein the step of visually distinguishing comprises using differing metals on each one of the plurality of different safety wires.