US2546026A - Flexible antenna mounting - Google Patents

Description

March 20, 1951 J. P. cooN 2,546,026

FLEXIBLE ANTENNA uounnuc Filed April 15, 1947 Inventor; James F? Coon, byM AM.

His" Attorhey.

Patented Mar. 20, 1951 FLEXIBLE ANTENNA MOUNTING James P. Coon, Syracuse, N. Y., assignor to General Electric Company, a corporation of New York Application April 15, 1947, Serial No. 741,655

6 Claims. 1

My invention relates to a flexible antenna mounting having particular utility in mounting a whip antenna on a radio equipped vehicle.

It is common practice in radio equipped cars, such as police patrol cars, to mount a mast or whip antenna on such a vehic e that extends up ward for several feet above the roof of the vehicle, necessitating some type of mounting that will permit the antenna to be deflected when it strikes an obstruction such as an overhanging limb, viaduct, doorway or the like.

Considerable difficulty has been encountered in the past in providing a satisfactory radio frequency connection when using such a flexible mounting. For example, when a spring is used for mounting the antenna, a flat braid has been used to make an R. F. connection through the spring. The initial installation of this connection is inconvenient and a positive connection is somewhat doubtful. The rate of breakage of this connection is also very high due to the fact that the braid must be long enough to enable the spring to be bent. When the spring is returned to the straight free position, the excess length of flat braid doubles up inside of the spring and works in between the turns of the spring and rapidly becomes chewed apart.

It is the object of my invention to provide a flexible antenna mounting with an improved radio frequency connection. The features of' this invention which I believe to be novel, are set forth with particularity in the appended claims. My invention itself, however, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which Fig. 1 is a fragmentary side elevation view of a radio equipped motor vehicle provided with an antenna which illustrates one embodiment of my invention; Fig. 2 is an enlarged vertical cross-section of the flexible mounting in upright position showing the R. F. connection; Fig. 3 is an enlarged top plan view of the flexible mounting; Fig. 4 is an enlarged vertical cross section view with the mounting flexed substantially 90 degrees.

Referring particularly to Fig. 1 of the drawing, I have shown a vehicle I, which may, for example, be a police patrol car, equipped with radio apparatus 2 comprising conventional transmitter equipment within the vehicle and a rod or whip antenna 3 extending upwards from a flexible mounting 4 which is supported on insulating base 5. The dotted line 3:: shows the antenna in a deflected position.

Fig. 2 is a vertical cross-section view of the flexible mounting 4 in which are shown the helical spring 6, each end of which is fitted over an end cap 1 and securely held thereto by friction or other suitable means. The end caps 1 are electrically connected together by means of the tubular braided metallic conductor 8. In each end of said conductor there is inserted a metallic plug 9 of approximately the same diameter as the inside diameter of the conductor 8 so as to form a solid portion upon which set secrews H] engage to secure conductor 8 in recesses I l in the center of the end caps 1. Each end cap has a threaded portion l2 for mounting and attaching the antenna 3. The two end caps may be substantially identical, as shown.

In normal operation the flexible joint is in an upright position as shown in Fig. 2. When the mast portion 3 encounters an obstacle, such as overhanging limbs, viaducts, low doorways and the like, the bending forces flex the helical spring 5, permitting the antenna 3 to deflect, for example, to a position as shown in Fig. 4. When this force is removed, the antenna is returned to its normal upright position by the spring 6.

When the antenna is deflected as described, the tubular braided metallic conductor acts somewhat like a bellowsv and has suflicient flexibility to stretch and bend in a radius similar to that of the helical spring, and returns to normal when the bending effort is removed. Since it is round, there is no tendency for it to get in between the turns of the spring. Also there is no excessive slack when in the upright position as, due to the construction of such a braided conductor, it lengthens and becomes smaller in diameter when tension is applied and returns to its original shape when tension is removed.

While I have shown a particular embodiment of my invention, modifications thereof will occur to those skilled in the art. I desire it to be understood, therefore, that my invention is not to be limited to the particular arrangement and methods disclosed, and I intend in the appended claims to cover all modifications which come within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A flexible mounting for a whip antenna comprising in combination a helical spring member, a substantially round plug member inserted in each end of said spring member, one of said plug members supporting the whip antenna and the other being adapted for mounting said spring member, and a tubular woven metallic conductor extending substantially axially of said spring, said conductor being electrically bonded to said plug members and having sufiicient rigidity to retain its tubular shape when said helical spring member is deflected substantially from its axis, the relative lengths and diameters of said spring member and tubular conductor being such that said conductor is supported away from the convolutions of said spring member when said spring member is bent through any angle of ninety degrees or less in an direction.

2. An antenna installation for a vehicle comprising a vertical member extending in normal operation a substantial distance above said vehicle, a helical spring member, a terminal member attached to each end of said spring member, said spring member having a greater coil diameter at its center than at its ends, means comprising one of said terminal members for supporting said vertical member, means comprising the other of said terminal member for mounting said installation on said vehicle, and a flexible tubular braided conductor electrically bonded to said terminal members and extending axially inside said spring members, said conductor having sumcient stiffness to retain its tubular form when said spring member is deflected from its vertical ax1s.

3. A flexible mounting for a whip antenna comprising in combination a helical spring member, a plug member fitted into each end of said spring member, means comprising said plug members for supporting a whip-antenna from a suitable support, and a flexible tubular braided conductor extending substantially axially or said spring member, said conductor being electrically bonded to said plug members and having svilicient stifiness to retain its tubular shape when said helical spring member is deflected substantially from its axis, the relative lengths and diameters of said spring member and tubular conductor being such that said conductor is supported away from the convolutions of said spring member when said spring member is bent through any angle of ninety degrees or less in any direction.

4. A flexible mounting structure for the whip antenna of a radio equipped vehicle comprising in combination a helical spring member, a cap secured to each end of said spring member, and a flexible tubular conductor electrically bonded to said caps and extending axially of said spring member, said conductor being braided to have suificient flexibility rigidity to retain its tubular form while flexing lengthwise when said spring member is substantially deflected from a vertical ax1s.

5. In combination, an antenna for moving vehicles, a support attached to said vehicle, a helical spring attached at one end to said support said antenna being attached to and supported from the opposite end of said spring whereby said spring permits free deflection of said antennav from normal when said antenna engages an object in its path of movement, and a flexible, braided tubular conductor for radio frequency currents extending from the base of said antenna through said spiral spring, said conductor having an elastic quality so as to elongate upon application of tension when said spring is deflected and to return to normal when said tension is removed the relative lengths and diameters of said spring and conductor being such that said conductor is supported away from the convolutions of said spring when said spring is bent through any angle of ninety degrees or less in any direction.

6. The combination of a whip antenna, a base, a helical spring attached to said whip antenna and to said base for supporting said antenna on said base, means for energizing said antenna comprising a tubular braided metallic conductor extending axially within the coils of said spring, said conductor being coupled to said antenna at one end and having sufficient resilience to flex lengthwise substantially without strain in ac.- cordance with the deflection of said spring,

JAMES P. COON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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