US3504108A

US3504108A - Wire stand-off

Info

Publication number: US3504108A
Application number: US774045A
Authority: US
Inventors: Joseph Kihs
Original assignee: Rohm Manufacturing Co
Current assignee: Rohm Manufacturing Co
Priority date: 1968-11-07
Filing date: 1968-11-07
Publication date: 1970-03-31
Anticipated expiration: 1987-03-31

Description

- LjKlHs March 31, "1970' WIRE STAND-OFF Filed Nov. 7. 1968 1 N VENTOR.

z/ose ob g M United States Patent U.S. Cl. 174154 2 Claims ABSTRACT OF THE DISCLOSURE A wire stand-off for electrical wire which has one end adapted to be attached to a cylindrical pole such as a pipe and the other end adapted to carry an insulator for receiving the electrical wire. The end adapted to be attached to the cylindrical pole has a substantially spirally wound wire section formed so as to encircle the pipe and springly engage it at four predetermined points spaced around the circumference of the pipe.

BACKGROUND OF THE INVENTION Field of the invention This invention relates to electrical wire guidance and insulation devices, and more particularly to a guidance device of the type usually known as a wire stand-off.

Prior art Wire stand-offs having substantially spiral ends for engaging a cylindrical pipe or rod are known to the art. (See for example my US. Patent No. 3,263,026.) However, such prior art devices have contacted the pipe or rod at only three places around its circumference. The first point of contact lay at least a quarter of the circumference of the pipe away from the point at which the extended arm of the stand-off began to spiral around the pipe. In this manner, a large moment arm was created allowing up-and-down movement of the long arm of the stand-oil which could weaken the gripping action of the stand-01f around the pipe.

SUMMARY The present invention overcomes the deficiency in the prior art by providing a wire stand-01f made of a single piece of formed wire rod which grips the cylindrical pole in four places. The stand-off of this invention can be easily attached to the cylindrical pipe by a simple twisting movement and, because of the four-point contact, will thereafter remain rigidly attached to the pipe.

The above-mentioned prior art problem of the long moment arm is avoided by having the first point of contact with the cylindrical pipe at the point where the extending stand-oft arm first reaches the periphery of the pipe and beginning the downward spiral directly at that point. This is accomplished by providing an angular bend adjacent the point of contact which causes the extending arm to project chordally to the pipe rather than tangentially as in the prior art. Thus the moment arm is reduced in length and caused to act against the pipe itself at the point of contact.

The angular bend besides projecting the mid-portion of the stand-off chordally from the pipe also provides a fulcrum point adjacent the bend and from 60 to 90 degrees away from the first of the intermediate contact points. This fulcrum point causes axial forces acting against the insulator to pivot against the pipe in such a manner that the force acts into the pipe either at the fulcrum point or at the free end of the spiral section. Further, because the fulcrum point grips the pipe partway around the circumference thereof from the first of the intermediate contact points it is possible to produce,

in selectively sprung spirals, a constant gripping between the two intermediate contact points.

In the preferred embodiment the free end of the spiral is bent radially inwardly a few degrees to enhance the gripping properties of the stand-off.

It is then an object of this invention to provide an improved wire stand-01f.

It is a further object of this invention to provide an improved wire stand-off consisting of a single piece of wire rod having one end formed to receive an insulator and the other end thereof formed spirally to encircle and grip a cylindrical object.

' It is a further and more important object of this invention to provide a wire stand-off having a spirally curved end adapted to encircle and frictionally engage the cylindrical object at four points therearound, which has an arm extending from the end of the spirally curved portion at an angle thereto chordal to the cylindrical object.

Other and further objects of this invention will be apparent to those skilled in this art from the following detailed description of the annexed sheet of drawings which, by way of a preferred embodiment of the invention, illustrates one example of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a plan view of the wire stand-off of this invention with a pipe illustrated by broken lines.

1 FIGURE 2 is a fragmentary top plan view of the wire stand-off of this invention illustrated encircling a crosssectioned pipe.

FIGURE 3 is a fragmentary plan view of the free end of the spiral portion of the stand-off of this invention in position on a pipe.

DESCRIPTION OF THE PREFERRED EMBODIMENT FIGURE 1 illustrates the wire stand-01f 10 of this invention. The stand-off is constructed of a single piece of wire rod 11 which has a straight mid-portion 12 adapted to extend outwardly from a pipe P. One end of the mid-portion 12 projects outwardly through a small angled bend 13 into a semi-circular end ring 14 adapted to receive and hold therein an insulator 15. The insulator 15 has a groove 16 therein for receiving a wire such as a flat television antenna wire.

The other end of the mid-portion 12 has a sharp small angled bend 17 therein through which the mid-portion 12 is integral with a portion 18 formed substantially spirally. The portion 18 terminates in a clawed or pointed end 19 approximately 410 to 450 degrees spirally beyond the bend 17.

The spiral portion 18 preferably has a diameter slightly smaller than the diameter of the pipe P around which the portion 18 spirals. In this manner, when the stand-01f 10 is placed in position around the pipe P, the spiral 18 will be slightly sprung to enhance the frictional grip of the wire rod 11 on the pipe P.

As in prior art devices, the stand-01110 contacts the periphery of the pipe P at the terminal end 19 and at twov

other points

20 and 21 angularly spaced from the end 19. In this manner, a three-point gripping of the pipe P is obtained. However, in prior art devices, the midsection 12 was tangential to the pipe P and the first area of friction engagement with the periphery of the pipe P and the wire rod 11 was angularly displaced from the point where the mid-section was tangent to the pipe. Thus -a long moment arm was created between the point of frictional engagement and the insulating device on the other end of the mid-section.

This prior art three-point frictional engagement allowed the axes of the spiral section to change through a twisting moment of the stand-off when subjected to high Winds acting on the antenna wire in a direction which would produce axial forces acting on the insulator. This is due to the fact that an axial force acting against the wire rod at the insulator would transfer to the spiral through the long moment arm of the mid-portion and the first point of contact would slide on the pipe surface with the pointed end acting as a pivot point for the spiral.

In order to overcome this objection, the present invention provides the small angled bend 17 thereby projecting the mid-point 12 chordally from the pipe P. That is to say that the stand-off section of the wire stand-off projects away from the pole on a plane which is chordal to the pole. In this manner, a fourth frictional gripping point 22 is created adjacent the exterior of the bight of the bend 17. This decreases the moment arm of the standoff to the area between the insulator and the bend 17. Further, it provides a fulcrum at the bend which causes any axial movement of the insulator end of the standoff to act against the entirety of the spiral end around the pole. In this manner, the first point of contact at the bend 17 tends to act as a pivot point and directs the force into the surface of the pipe at the chordal angle. Therefore, a firmer frictional gripping engagement is obtained around the pole.

It is to be understood that although the fulcrum is described as being at the bend, the actual contact point is spaced a short distance from the bend as can be seen in FIGURE 2. It is further to be understood that although the specification has descriped a four-point contact having a gripping relationship with the pipe at

points

19, 20 and 21 and 22 that in those instances where the spiral portion has been sprung to a sufficient degree in gripping an increased diameter pipe, the contact points 20 and 21'may be closer together and provide for continuous contact between the

points

20 and 21 producing in reality a threepoint contact. Even though such is a true three-point contact the objects to the prior art are still overcome because of the fulcrum contact and the chordal projection of the mid-portion 12. Therefore axial forces will be directed either into the pipe at the fulcrum point in the case of upwardly directed axial forces or into'the pipe at the clawed end 19 in the case of downwardly directed axial forces.

It is to be understood that although the portion 18 has been described as being a spiral, it is not necessary that it have a consistently specific diameter, but that the end portion 19 may be bent inwardly and have a shorter radius to enhance its gripping abilities. It is also to be understood that the bend 17 and the point of the section 18 directly below the bend 17 are spaced apart approximately the diameter of the pipe P to facilitate attaching of thestand-olf to the pipe, which attachment is made in substantially the same manner as in prior art devices.

Inserted in the preferred commercial embodiment of this invention, the spiral section of the stand-off is sized so that contact is continuous between

points

20 and 21. Further, to enhance the ability of the stand-off to resist circular movement around the pipe the free end 26 of the spiral section is bent radially inwardly at a point 27 in close spaced relation to the end. The end is bent only a few degrees. As can be seen from FIGURE 3, this bend 27 urges the free end 26 into sharper angle contact with the pipe P thereby resisting circular rotation of the standoff. This bend also aids in bringing the spiral into contact with the pipe continuously between the

points

20 and 21.

I claim as my invention:

1. A cable stand-off for use in association with a cylindrical pole comprising: a straight wire rod mid-portion, a

semi-circular ring at one end thereof integral therewith,

insulating means within said ring, a substantially spirally wound pole gripping portion at the other end of the said mid-portion integral therewith through a small angle bend portion, said spirally wound portion adapted to encircle and frictionally engage at only four spaced points the said cylindrical pole, one of said points at the end of said spirally wound portion remote from said midportion, a second of said points adjacent the said smallangled bend portion, said other two points intermediate said first and second points, the said bend portion projecting the said mid-portion from the said spiral portion chordally to the inner diameter of the said spirally wound portion, and the said second point providing a fulcrum for the said mid-portion and ring against the periphery of the said pole.

2. The stand-off of claim 1 wherein the spiral wound portion has a diameter smaller than the diameter of the pole to which it is to be attached whereby attaching the stand-off to the pole results in a springing or dimeter increase of the spiral portion to create constant contact against the circumference of the pole between the said other two points.

References Cited UNITED STATES PATENTS 2,459,514 1/ 1949 Flickinger 248-302 X 2,627,276 2/1953 Eggleton. 2,767,240 10/ 1956 Webster et al. 3,263,026 7/1966 Kihs 174154 3,381,824 5/1968 Blumenschein 248302 X LARAMIE E. ASKIN, Primary Examiner U.S. Cl. X.R.