US2763341A

US2763341A - Extensible and collapsible antenna mast

Info

Publication number: US2763341A
Application number: US193771A
Authority: US
Inventors: Gerald G Wentworth
Original assignee: Individual
Current assignee: Individual
Priority date: 1950-11-03
Filing date: 1950-11-03
Publication date: 1956-09-18
Anticipated expiration: 1973-09-18

Description

Sept. .18, 1.956' G, G. wEN-rwoRrH EXTENSIBLE AND COLLAPSIBLE ANTENNA MAST 2 Sheets-Sheet I F'ld NOV. 3, 1950 Inventor Gera/d 6. Weniworfh sept.- 1s, 1956 G. G, WNTWR'TH 2,763,341

EXTENSIBLE AND COLLAPSBLE llq-TENIQIA MAST Filed Nov. s, 195o 2 Sheets-Sheet 2 l Inventor Gerald 6. Wen/worth ama/Wawy .6mm

United States Patent O 2,763,341 EXTENSIBLE AND COLLAPSIB'LE ANTENNA MAST Gerald G. Wentworth, Houston, Tex. Application November 3, 1950, Serial No. 193,771v 2 Claims. (Cl. 1879-26) This invention relates to extensible and retractible mast structures for antennae and more particularly to structures for television antennae which are erected on housetops or roofs or on the ground for the purpose of bringing the radiation receiving element of the antenna into a position in which said element is clear of interference by surrounding objects. l

Mast structures for small and inexpensive antennae, such as television antennae must be made collapsible for the purpose of transportation and especially for bringing them to the location on which they are mounted for nstance to the roof, and the construction should be of such a type that a single operator is able to perform the mounting of the mast and antenna in the shortest possible time. Nevertheless, the antenna mast and antenna must be capable of withstanding the considerable strain and stress to which it is subjected by atmospheric conditions.

While collapsible and extensible antenna mast constructions are known most of-these constructions are not suitable for the conditions prevailing in the case of a television antenna mounted on a private home. The mast structure must not only be of light weight and of very limited size when collapsed, but must also be extensible to considerable length by a simple manipulation. Moreover it must not only be safely locked, when in extended condition, against collapsing, but must also be provided with means which preventrthe unlocking or releasing ofthe locking means by the considerable forces which are acting'on the antenna and the mast. l

It is therefore an object of the invention -to provide a mast structure for antennae of this type with telescoping members which lock themselves automatically when brought into their extended position and which cannot be unlocked by the stress or strain produced by the forces acting upon the antennae.

It is a further object of the invention to provide a mast structure for antennae of this type with telescoping rods or tubes which are safely locked when extended and which unlock themselves automatically by means of a simple manipulation without any regard tothe strain to which the antenna or antenna mast is submitted by gravity or by prevailing atmospheric conditions.

It is a further object of the invention toqprovide'an extensible and collapsible mast of the telescoping tube type in which the telescoped tubes are positively held With respect to each other, said positive engagement between the tubes also permitting the maintenance of their rotational relationship so that the mast can be used for rotatable antennae which undergo orientation and are rotated by the user.

It is a further object of the invention to providean extensible and collapsible mast of the type using telescoping tubes which are automatically locked and which unlock themselves automatically if a relative movement of the rods, excluded when the antenna .is mounted and locked, is imparted to them manually, said unlocking pro` ducing the collapsing of the extensible members.

It is a further object of the invention to provide means whereby an effective antenna member. (such as a dipole,

the examples were selected in order to explain the princi-` ple of the invention and the bestmode of applying said principle. The specification and drawings do not attempt to give a survey of all the possible modifications of the invention and a departure from the examples shown is therefore not necessarily a departure from the principle of the invention.

In the drawing:

Figure l is an elevational sectional view of the extensible and collapsible mast structure, the section being taken through one of the planes of symmetry.

Figure 2 is a perspectiveview of the divided sleeve holding the radiation receiving element of the antenna.

Figure 3 is an elevational sectional View illustrating the locking device, the section being taken along the line 3--3 ofFigurel.

Figure 4 is a sectional plan view, the section being taken along line 4--4 of Figure13.

Figure 5 is an elevational partly sectional view of the uppermost part of a modication of the. antenna, the section being taken through one ofthe planes of symmetry passing through the axis of the mast.

Figure 6 is a diagrammatic elevational view of the antenna. `As has been explained before there frequently arises the necessityof placing a television antenna high above the structure on which it is supported in order to bring the radiation receiving portionor member of the antenna into a position in which'it dominates the surroundings to a certain extent and in which it may pick up the short wave radiationuwithout interception by other structures or in which .the antenna listo be removed from sources of local interference due to reflection or the like.

As masts of considerable height are ditlicult to handle especially when they are to be mounted on a roof, extensible and retractible masts consisting of telescoping tubes have been proposed, the extensible elements of which are provided with locking devices which are capable of locking said' elements in their extended position. However certain diiculties are experienced in connection with such devices as the locking and the erecting of the mast in general sometimes entails a rather complex manipulation. A simple manipulation for erecting the antenna mast and for collapsing the mast is however not only necessary in order to save labor and cost but is especially indispensable in those places in which tropical storms with very high wind velocityoccur and in which therefore the antenna must be dismounted in the event of a storm, as antennae of this type cannot usually be constructed to withstand excessive strain without unduly raising the cost of the en tire installation. p The invention therefore comprises essentially a collapsible mast structure with telescoping tubes which are self locking and self-unlocking and which may be erected'on a housetop or on theA ground with a small number 0f slmple manipulations, such as the pulling out of the telescoping rods or the fixing of the guy wires, manipulations which may be undertaken by unskilled persons. Likewise the dismountingv must be performable by unskilled persons Patented Sept. 18, 19756 and therefore the antenna must be provided with automatic unlocking means which cannot be unlocked by the load or lateral stresses but which produce automatically collapsing of the mast upon a simple manipulation.

More specifically it is customary to provide unlocking means based on frictional resistance or on the withdrawal of 4locking members. Such unlocking means are however usually unsafe or very diicult to operate when under load. According to the invention however the locking and unlocking means are of the positively and automatically locking type and are disengaged automatically upon a relative movement of the telescoping rod which cannot be produced by load or by lateral forces and which is not affected or impeded by said forces.

v The telescoping mast structure for television antennae according to the invention comprises a number of telescoping tubes or rods 10, 11', 12 fitting into each other and each provided at its upper end with a collar 16, 17 having a downwardly curved portion 19 to which the guy wires 20 may be attached. The collar is provided with a number of holes 22 corresponding to the number of guy wires used and loops at the end of the guy wires are passed through the said holes. The tubes are moveover provided with automatic locking devices for locking them when extended. For this purpose each tube is provided at its lower end with a substantially triangular opening 25 preferably equipped with rounded corners. The apex of the triangle is vpreferably turned upwardly. The side walls of the triangular opening lie in a plane which is downwardly inclined relative to the surface of the tube forming a fiattened notch therein. The lower edge 26 of the triangular opening 25 has therefore the shape of an inwardly extending lip as seen in Figure 1 in order to permit the flattening or depression of the portion of the tube at which the opening is provided.

Each tube is moveover provided at its top with a locking latch 30 consisting of an elastic spring arm 31 which may be spot welded or otherwise fixed to the tube at one end. Said arm is provided with a projecting tongue or locking member 32 at its end. The projecting tongue or locking member passes through the hole 33 in the tube so that it may reach the interior within which the telescoping tubes 11, 12 may slide.

As will be clear the tongue or locking member 32 enters the opening 25 and thus is capable of supporting and locking an inner tube whenit has been drawn out sufficiently to bring the opening 25 in front of the locking latch or dog 30. The lip 26 forms a surface on which tongue 32 can ride until seated in one of the rounded corners of opening 25.

At the upper end of each tube a mark 35 is arranged whichindicates the position of the opening 25 within the covered portion of the tube which is surrounded by an outer tube.

Intorthe uppermost tube a sleeve 40, divided longitudinally along a plane passing through its axis into two

half sleeves

41, 42 is inserted. This sleeve has a cylindrical lower portion 45 fitting exactly into the interior of the uppermost tube 12 and a tapering or somewhat conical upper portion 46 the smaller diameter of which is at its lower end and'is slightly smaller than that of the cylindrical sleeve while the diameter at the upper end of the tapering portion is larger than the diameter of the 4tube 12. The cylindrical portion 45 of this divided sleeve may therefore slide down within the uppermost tube 12 until the tapering portion 46 rests rmly in the orifice of the uppermost tube 12.

, The said divided sleeve has a central cylindrical bore 48 of such width that a standard size mast piece 49 of a television antenna 50 will be firmly held in said bore. The mast pieces which carry the television antennae are usually made of a pipe length of a standard size and the antenna proper is attached toV them by means of U-shaped bolts. It will be noted that Vthe above described construction permits to grip this mast piece 49 firmly between the two

halves

41, 42 of the divided tube 40, as the two half tubes are firmly pressed towards each other when the sleeve is pushed downwardly by the weight of the mast and antenna structure. Any small difference in size between the mast and the bore of the sleeve is thus automatically eliminated as the length of the tapering portion 46 which reaches down into the tube 12 may slightly vary accordingly. The mast and

antenna structure

49, 50 is therefore firmly held without any necessity of adjustment by the operator erecting the structure and the firm grip of the mast holding the antenna is such that it withstands all forces resulting from winds of normal strength. No noise due to play between the parts can therefore be produced.

The tube 10 is fixed to a roof of a building in the well known manner.

The telescoping mast structure according to Figures 5 and 6 is slightly modified and reinforced so as to be suitable for a mast construction to be erected on the ground. The telescoping mast structure differs from that shown in Figures 1 to 4 merely by the duplication of the locking latches or dogs 36 which are arranged on two opposite sides of the tubes 10, 11 and by the reinforced collars 27 which are welded to the upper ends of the tubes and which are therefore adapted, to accommodate heavier guy wire loops.

A complete structure erected on the ground is shown in Figure 6 diagrammatically. The lowermost tube 10 is secured in the ground in the well known manner which need not be described and the telescoping extensible and collapsible structure is then erected in the same way in which the corresponding structure is erected on a house roof.

In order to erect a telescopic mast structure as before described, the operator mounts the lowest pipe or tube 10 on the roof or on the ground in t-he same way in which non-telescopic masts are mounted. The tube may pass from the outside into the house, if the structure is rotational for orientation purposes. The guy wires must all be attached to the collars before the mounting operation starts and the erection of the expansible and ex tensible mast may now proceed. The operator inserts the antenna Si) with a short attached antenna mast section 49 into the sleeve 40 and also turns the antenna into the direction which has been selected. Then the operator raises the innermost tube 12 until the latch locking device 30 snaps into the triangular opening 25. The mark 35 indicates to the operator whether the triangular hole or opening is in proper position. Once the locking device 30 has snapped into the opening 25 the operator may release the tube which he holds in his hand and may permit the tube 12 to slide down. The tube will then automatically come to rest on the tongue 32 of the dog or latch in the apex of the triangular opening 25 as the sides of the triangular opening will guide the tongue of the latch. The tongue supports the weight of the tube in this position which is a perfectly fixed one. The operator may now raise the next tube 11 proceeding in the manner aforedescribed. When the mast has been fully extended the guy wires are fixed and the antenna structure has reached the place which is assigned to it, the direction towards which the antenna points being also a fixed one corresponding to the direction which was selected by the operator when inserting the antenna Si).

vThe manipulation which has been described is extremely simple and takes only a very short time.

To dismount the antenna the guy wires are loosened and the tube 11 projecting from the tube 1G which is fixed to the roof is slightly raised and is turned around through an angle of around The raising of the tube 11 disengages the tongue 32 as the said tongue now leaves the opening which is inclined but merely projects into the space which 'is left free and which is enclosed between the flat portion of the inner tube and the cylindrical portion of the outer tube. The dog or latch 30 thus permits the rotation of the tube 11 during which the said tongue Will come to rest against the outside of the tube 11. The said tube may now slide down as it is no longer held by the latch or dog 30. After the tube 11 has been lowered the next tube 12 is handled similarly. Again the mark 35 will assist the operator to locate the proper position of the covered opening 25. The removal of the antenna 50 with the attached mast 49 is performed by raising the sleeve 40 slightly, thus separating the two halves to the extent which permits such removal.

On account of the fact that no turning of the tubes can occur when the guy wires are iixed it is not possible that any strain imparted to the extensible and collapsible structure or any force applied from without may unlock the automatic locking device. While on the other hand such unlocking occurs automatically as soon as the tube is raised by the operator and is slightly turned.

It will be clear that the invention has been described in specific terms; changes of an unessential nature will not in any way affect the principle of the invention as defined by the annexed claims.

Having described the invention, what is claimed as new is:

1. An extensible and collapsible antenna mast structure having telescoping cylindrical tube sections surrounding each other comprising a movable supporting tongue member xedly carried on the outside of each telescoping tube, said tube being provided with a hole through which the supporting tongue member projects inwardly, a flattened inwardly and downwardly inclined notch on each tube near the lower end of the same, said flattened notch forming a substantially triangular opening cooperating with the tongue member to support the cylindrical tube, the side walls of said flattened notch being tapered from top to bottom whereby the lower apices of the triangular opening are spaced inwardly of the upper apex, the apex of the triangular opening being near the point at which the said attened inwardly and downwardly inclined notch joins the cylindrical section of the tube, the portion of the triangular opening near the apex being brought into register with the hole in the enclosed cylindrical tube Vthrough which the tongue member carried on the outside of said surrounding tube projects into the interior of the same, the bottom of said opening being inwardly spaced from said surrounding tube a distance greater than the length of said tongue member, said mast structure being brought into extended condition by raising successively the inner tubes bringing the apex of the triangular opening of each tube into register with the supporting tongue member projecting from the encircling tube so that the wall of the inner tube may rest on the tongue member when under the influence of gravity, and said mast structure being collapsed by lifting the inner tube until the tongue member is free of the downwardly and inwardly inclined opening and then rotating the said tube whereby the tongue member is brought to bear against the cylindrical wall of the inner tube and is no longer capable of supporting the same so that the inner tube may telescope into the outer tube under the action of gravity.

2. An extensible and collapsible antenna mast structure with telescoping cylindrical tube sections, comprising a latch member ixedly carried on the upper eud of each tube encircling a telescoping tube, said tube having a hole near its upper end, a flattened downwardly and inwardly inclined substantially triangular notch near the lower end of each tube encircled by another telescoping tube, said notches being provided with an inwardly projecting lip, said flattened triangular notch defining a `triangular opening the apex of which is located near the upper end of the flattened notch where the latter joins the cylindrical section, the side walls of said flattened notch being tapered from top to bottom whereby the lower apices of the triangular opening are spaced inwardly of the upper apex, an inwardly projecting tongue member on said latch member projecting through the hole near the upper end of the tube into the interior thereof and fixedly mounted on a resilient carrier xedly held by said tube, the bottom of said opening being inwardly spaced from said surrounding tube a distance greater than the length of said tongue member, the tongue being of a length not exceeding the length of the inwardly projecting lip, the tongue of the latch member thus, when a tube is drawn out until the triangular opening at its lower end registers with the hole on the upper end of the encircling tube through which the tongue of the latch member projects, supporting the inner tube when it catches the apex of the triangular opening, the mast being collapsed by lifting each tube until the tongue member is clear of the triangular opening in the inwardly and downwardly inclined surface, and then rotating the tube whereby the cylindrical surface of the inner tube presses on the tongue member without however holding it up against gravity.

References Cited in the file of this patent UNITED STATES PATENTS 143,879 Cathcart Oct. 21, 1873 426,036 Michael Apr. 22, 1890 544,478 Damm Aug. 13, 1895 838,519 Bremer Dec. 18, 1906 839,297 Kennedy et al. Dec. 25, 1906 849,860 Searle Apr. 9, 1907 923,714 Searle June l, 1909 1,284,358 Kelley Nov. 12, 1918 1,337,487 Schlatter Apr. 20, 1920 1,581,325 Sands Apr. 20, 1926 1,644,613 Royer et al. Oct. 4, 1927 2,321,028 Johnson June 8, 1943 2,369,534 Cohen Feb. 13, 1945