US1587872A - Means for supporting antenne used in wireless telegraphy - Google Patents

Description

June 8 1926. 158K872 s'r. GEIGRGE-MGURE ET AL MEANS FOR SUPPORTING ANTENNAE USED IN WIRELESS TELEGRAPHY Filed Sept. .16, 1920 Patented June 8, 1926.

UNITED STATES PATENT OFFICE.

RICHARD ST. GEORGE-MGOEE OF LONDON, AND GEORGE SCOVELL WHITMORE, OF EASTCOTE, ENGLAND, ASSIGNORS TO RADIO CORPORATION OF AMERICA, A COR- PORATION OF DELAWARE.

MEANS FOR SUPPORTING ANTENNEE USED IN WIRELESS TELEGRAPHY.

Application filed September 16,

IVireless antennae have frequently been supported by means of a wire or cable led over a sheave at the top of a mast and secured to an anchor behind the foot of the mast, the portion of the wire or cable between the sheave and the anchor acting as a back stay or guy rope, but this method of supporting the antenna results in a bending stress being applied to the mast. Obviously this bending stress can be reduced by increasing the distance between the foot of the mast and the anchor, but the stress cannot be entirely eliminated in this way, and moreover it is very inconvenient to locate the anchor at a great distance from the mast.

The object of this invention is to provide improved means for supporting an antenna by the use of which means the resultant stress upon the mast shall be entirely vertical.

According to this invention we provide means for connecting an antenna to a back stay in such a way that the tension of the back stay may be greater than that of the antenna and that the resultant stress upon the mast may be vertical.

According to one method of carrying this into eliect we pivot to the mast a bell crank lever having arms of different length and we attach the antenna to the longer arm and the back stay to the shorter arm, the proportion between the lengths of the arms and the angle that the back stay makes with the mast being so chosen that the resultant stress on the mast is vertical.

Or preferably in place of a lever we mount in bearings at the top of the mast two drums of diiierent radii and wind the antenna cable several times around the larger drum and the back stay several times round the smaller drum, the proportion between the radii of the two drums and the angle that the back stay makes with the mast being so chosen that the resultant stress upon the mast is vertical. This arrangement has the advantage that should either the antenna or the back stay break the other can unwind to such an extent that its pull upon the mast will be innocuous. Preferably one of the drums can be rotated independently of the other but can be se cured to it when the desired tension has been put on the antenna and back stay.

1920, Serial No. 410,648, and in Great Britain November 3, 1919.

According to another method we provide at the top of the back stay a sheave and we pivot a sheave to the top of the mast and lead the antenna cable over this second sheave and'round the first and then either secure it to the top of the mast or preferably lead it round a guide pulley at the top of the mast to the ground so that it can be used as a halyard for tightening the antenna and back stay. The angle that the back stay makes with the mast can then be adjusted according to the point of attachment of the antenna cable so that resultant stress upon the mast will be vertical.

Our invention is illustrated by the ac companying drawing, in which Fig. 1 shows our invention as applied to the mast carrying a drum of two diameters. Fig. 2 shows a modification wherein the angle which the back stay makes with the ground is fixed, and Fig. 3 shows a modification of Fig. 1 wherein a bell crank lever having two arms is used instead of a two diameter drum.

In Figure 1, A is a mast at the top of which are journalled a drum B around which the antenna cable C is wrapped and a drum D around which the back stay E is wrapped. It then we assume that the antenna cable is horizontal, by anchoring the back stay at a point at such a distance from the foot of the mast that the cosine of the angle the back stay makes with the horizontal is equal to the ratio of the radius of drum D to the radius of drum B, the re sultant stress upon the mast will be vertical.

In Figure 2 the antenna cable is led over a sheave G at the top of the mast round a sheave H at the top of the back stay and over a pulley 1 at the top of the mast and is then attached to the foot of the mast. In this case if the back stay makes an angle of 60 with the horizontal the resultant stress on the mast will be vertical. By attaching the end of the antenna cable to a point on the ground on the same side of the mast as is the anchor F the distance between 'the anchor and the foot of the mast may be reduced. On the other hand, if it is desired to attach the end of the antenna cable to a point on that side of the mast which is remote from the anchor, the distance of the anchor from the foot of the mast must be increased.

Fig. 3 shows a modification of Fig. 1 in which a bell crank lever K having two arms L and M respectively of different lengths is pivoted to the mast A and as in Fig. 1 the antenna is connected to the longer arm and the back ay to he shorter,

Having now particularly described and ascertained the nature of our said invention and in What manner the same is to be per formed, We declare that What We claim is 1. The combination of a mast, an antenna, a bet k, Stay a two drums Qt di erent ra i ur all'ed Q1 the meet he a t nna being Wound round the larger drum and the back ay b ng o nd r m' cl t maller, and h adi at th rum b i g s chosen; th t th sultan t ess pon t mast m y be w -a su st ti lly. a descr e 2a Th qm'b ne i n- Q-f meet, a substanly horizon al able, a ro a a e m m er mounted upon mast, and a back stay, aid able a d sai ba k taybe ng se ured to Sai qtatab e mem er and th distance between the center of rotation of said rotatable member and the point of attachment of said cable being greater than the distance between said center of rotation and the po nt o a ta hm nt a d backstay su stantially as and for the purpose described.

3. In combination a mast, a substantially horizontal cable, a rotatable member carried by said mast and a backstay, said cable and said backstay being attached to said rotatable member at difi'erent distances from the center of rotation thereof, the tensions in said cable and said backstay being so chosen that the horizontal force acting upon said mast is zero and the distancesbet'ween the center of rotation of said rotatable member and the points of attachment of said cable and said backstay being so chosen that the turning moment actingthereon is also zero.

RICHARD ST. GEQRGE-MQORE. GEORGE SCOVELL WHITMORE.

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