US2144038A - Aerial and aerial mounting arrangement - Google Patents

Description

Jan. 17, 1939. E. H. TRUMP AERIAL AND AERIAL MOUNTING ARRANGEMENT Filed Oct. 24, 1956 \NVENTOR E H TRU M P BY *5 9 ZWM ATTORNEY Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE AERIAL AND AERIAL MOUNTING ARRANGEMENT Application October 24, 1936, Serial No. 107,342

In Great Britain October 24, 1935 8 Claims.

This invention relates to aerial and aerial mounting arrangements and has for its object to provide an improved aerial mounting arrangement suitable for use upon vehicles, for example, upon tanks. More specifically, the invention seeks to provide an aerial mounting arrangement which can be satisfactorily employed without serious risk of damage upon a vehicle which may be required to travel over such rough ground that the aerial may be subjected to mechanical violence not only due to vibration and varying wind pressure but also due to collision with obstructions.

According to this invention an aerial is car-- ried from a vehicle by means of one or more springs which support the said aerial but will allow it to be moved away e. g. by collision with an obstruction, from its normally supported position and return it to said normally supported position afterwards.

Preferably the spring support for the aerial is constituted by two helical coil springs, one spring being a closely wound spring with considerable residual tension and the other (which is prefer- 26 ably inside the first spring) being a second helical spring stretched under heavy tension and secured between the two ends of the outer spring. Preferably also the aerial itself is of relatively flexible structure and is supported so as to be 80 normally in the same straight line as the spring mounting means therefor.

In cases where a very light, small aerial only about four or five feet in length is required to be mounted above a vehicle, the said aerial may 35 be mounted quite simply by means of a helical spring one end of which is attached to a convenient point on the vehicle and the other end of which is attached to the aerial and forms its only support. In general it will be preferable 4 for the lower end of the aerial and the upper end of the supporting spring to coincide and for the axes of the spring and aerial (when in normal position) to be in the same straight line.

This simple form of spring mounting is, how- 5 ever, only satisfactory for relatively short and light aerials and when longer and heavier aerials are to be employed a multiple-spring support arrangement, such as that described below and illustrated purely schematically in the accom- 50 panying drawing should be adopted.

In the generally preferred construction in accordance with this invention and illustrated in the accompanying drawing the aerial is mounted upon a spring mounting constituted by two heli- 55 cal springs, I, 2, one inside the other, the outer spring I being closely wound with considerable residual tension and the inner spring 2 being stretched under heavy tension as shown. The provision of the inner spring may be regarded as equivalent to providing an outer spring with 5 an increased residual tension. The outer spring I is carried by means of a suitable insulator 3 from the roof 4 of the tank or other vehicle, the lead-in conductor 5 passing through said insulator to the inside of the vehicle. A flexible l0 conductor 6 electrically short circuits the spring mounting so that the high frequency currents induced in the aerial do not have to pass through the spring. The conductor 6 should be so designed and fitted that, in normal use, it never 15 touches the spring. Lead 5 may be secured to the end of conductor 6 as by a screw M.

The aerial itself is in the same straight line with the normal longitudinal spring direction and, as illustrated the said aerial is made after 20 the manner of a large tubular metal fishing rod comprising a plurality of tubes 1 of different diameters (the upper tubes being smaller) fitted into one another. This gives a very light and flexible construction. A cord 8 or the like is fixed at one end to the top section or tube of the aerial and passes down inside the tubes to a bobbin 9 firmly fixed to the aerial and coaxial with it. The other end of the cord is fixed by means of the grub screw ID to the bobbin leaving a loop of cord. This loop is wound upon the bobbin until only a small bight or V is left and this is then slipped over one of four evenly spaced pegs (not shown) provided on the bobbin to receive it. When the cord has been tightened in this way the aerial is mounted in position the bobbin being then covered over as shown by being inserted in the housing formed in the mount and indicated by the broken line H. The pegs for retaining the V or final bight of cord are of such length that there is only a small clearance between the tops of the pegs and the interior of the housing so that, when the bobbin is in position in the housing there is no room for the bight to slip off its peg. Thus the cord which is normally tight, assists in holding the aerial tubes together. When the cord loop is unwound the aerial tubes can be pulled apart to the extent of a few inches and the aerial folded up to occupy a small space, the cord preventing the loss of any aerial tube. In the event of an aerial tube being damaged the end of the loop can be released by removing the grub-screw l0 and the aerial can now be dismantled and a new tube fitted. The aerial, with its bobbin and cord,

is fixed in position on the spring mounting in any convenient manner. In the example given the housing H fits within a bore of a supporting cap H? which is secured to the upper end of the springs l, 2.

With the aerial construction illustrated, if only the top of the aerial is struck by an obstruction, the aerial itself will probably bend sufficiently to prevent damage although in any case the spring supporting means will yield, if necessary.

The spring or springs: employed in carrying out the present invention may be arranged to be adjustable as to tension so that in any given installation upon a vehicle there will be a range of adjustment to permit of the installation being adjusted to the best resilience or yielding power.

In place of providing an insulator between the spring mounting and the vehicle, an insulator may be provided between the spring mounting and the aerial. I

The invention enables aerials to be carried upon vehicles, such as tanks, without serious risk of damage to the aerial and without permitting any undesirably large mechanical vibrations r oscillations of the aerial in normal circumstances.

Having now particularly described and ascertained the nature of my invention and in what manner the same is to be performed I declare that what I claim is:

1. An antenna installation for a vehicle comprising, a plurality of axially aligned tubular metallic members of successively decreasing diameter, said members being adapted to be assembled to form a hollow rod, a cord passing through said member, one end of said cord being attached to the small end of the rod, means connected to the member at the large end of the rod for gripping said cord, said last named means being arranged to hold the cord taut to thereby hold the members in position, a supporting member secured to said vehicle, an outer spring secured to said supporting member and being closely wound with residual tension, an inner spring stretched under tension, and means for connecting the large end of the rod to the outer portions of said springs.

2. An arrangement as described in claim 1 characterized by that the supporting member is formed of insulation material, and means are provided for securing said member to a portion of said vehicle and by that said spring is tensioned to maintain the rod in a substantially vertical position.

3. An arrangement as described in claim 1 characterized by that the gripping means is operable to loosen the cord sufficiently to permit taking down the antenna rod.

EDWARD HERBERT TRUMP.

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