US2239614A - Extensible aerial - Google Patents

Description

April 22, 1941. c. w. MARTIN EXTENSIBLE AERIAL Filed Jan. 29, 1940 2 Sheets-Sheet 1 I N VEN TOR.

CARY W.MART|N ATTORNEYS April 22, 1941- c. w. MARTIN EXTENSIBLE AERIAL 2 Sheets-Sheet 2 Filed Jan. 29, 1940 22A FIG.8.

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CARYWMARTIN 1.1; 74 m? ATTOR lays Patented Apr. 22, 1941 2,239,614 EXTENSIBLE AERIAL Gary W. Martin, Los Angeles, Calif.

Application January 29, 1940, Serial No. 316,153 12 Claims. 401150-43) This invention relates to extensible radio antennae, particularly for motor vehicles, having as its principal object the provision of an improved power-operated extensible and retractible i aerial which, when retracted, is almost entirely concealed within the body of the vehicle, but

which is readily extensible, by the mere operation of a button-like control located in the passenger compartment, to project to any desired extent within its range of movement.

Aerials constructed in accordance with the present invention incorporate a cylindrical casing within which the antenna is housed when retracted, and within which a piston travels to actuate the aerial. The piston in turn is actuated, under the control of a valve, by means of suitable pres-sure changes, which may be derived from the intake manifold of the engine of the vehicle. In the operation of aerials of this class, it has been difficult to keep water from entering the casing-cylinder, and there short-circuiting the antenna. Since a reduced pressure existsin the casing cylinder during operation of the aerial, a positive pressure difference tends to force water 1 into the interior. It has been the practice to pro-,

vide stuffing boxes at the point of emergence of the antenna rod, but these cannot be completely air tight under all conditions, and the means for increasing the actuating pressure in,

vacuum within the cylinder accordingly has been i sufiicient to draw water into the cylinder, in numerous instances. Inasmuch as a drop or two of water within the cylinder of such an aerial is sufficient to destroy its efiiciency, this difiiculty has been an extremely serious one. An important object of the present invention, therefore, is to provide improved and simplified means for positively preventing entrance of water to the cylinder of an antenna of the character indicated. Inasmuch as the room which is available within the body of modern motorcars for installation of aerials of this class is very limited, it is necessary that the operating cylinders be of small diameter, and this in turn limits the power available to operate the same if manifold pressure is used as the motivating agency. It is accord ingly not feasible to utilize tight stufling boxes, or other sealing means which would impose material resistance to movement of the rod, and a further and related object of the present invention is to provide means for positively preventing entrance of water to the casing or cylinder without increasing the drag upon the antenna element and the power required to operate the same.

Still another object-is to provide such an operative antenna having a grounded metallic casing cylinder which serves as an electrical shield for the antenna, when retracted or partly re- .tracted thereinto, preventing electrostatic and electromagnetic influences within the Vehicle body from affecting radio reception, while at the same time providing an actuating cylinder for the antenna, the piston comprising an insulating r member and cooperating with other insulating means to insulate the antenna from the casing cylinder.

A further object is to provide improved means furnishing electrical and pneumatic connections 1 to the antenna and to the operating means therefor, the electrical connection being of such efficiency that undue electrical losses, noises in the radio receiver and other troubles which accompany inefficient aerial connections are eliminated,

j despite the fact that a friction connection of the sliding type is employed.

Still another object is to provide improved proportion to the size of such an antenna, and to provide extremely simple and positive means whereby such an aerial of very compact proportions, consisting of a plurality of telescoping sections, may be projected and retracted in a manner rendering fully automatic the movement of all of such sections.

Other objects and advantages will be apparent from the following description, wherein reference is made to the accompanying drawings illustrating preferred embodiments of my invention and wherein similar reference numerals designate similar parts throughout the several views.

In the drawings:

Figure l is a fragmentary and somewhat diagrammatic view showing in vertical section the forward portion of a motor vehicle equipped with an aerial constructed in accordance with the present invention.

Figure 2 is a longitudinal elevational view principally in substantially diametric cross section, but partly in side elevation, and centrally broken away.

Figure 3 is a cross section taken substantially on the line 33 of Figure 2, and looking in the direction of the arrows.

Figure 4 is a detail sectional view, on a larger scale, of a part of the telescoping antenna element, showing the friction and contact means by which the extension portion is held against unwanted movement and maintained in proper electrical contact with the outer section.

Figure 5 is a side elevational view of the control valve.

Figure 6 is an enlarged substantially diametric cross sectional view thereof.

Figure 7 is a cross sectional view taken substantially on the line 1-1 of Figure 6, and lookin in the direction of the arrows,

Figure 8 is a view similar to Figure 1, showing a somewhat modified construction.

Figure 9 is a longitudinal sectional view thereof, similar to Figure 2.

Figure 10 is a substantially diametric sectional view of the separate vacuum and pressure cylinder assembly which is employed to boost the actuating pressure in the modified embodiment; and

Figure 11 is a cross section taken substantially on the line of Figure 9.

Referring now to the drawings:

Reference character |8 designates generally the body of a motor vehicle, which is illustrated fragmentarily and only in sufiicient detail to indicate the manner of installation of my improved antenna construction, inasmuch as the construction of the vehicle forms no part of my present invention. The vehicle is shown as provided with an engine l2 having an intake manifold I4, and an engine hood l5. A dash panel l1 separates the engine compartment from the passenger compartment, 28, and a cowl 22 covers the portion of the passenger compartment forward of the windshield. An instrument panel 25, located in the passenger compartment, serves to support a control valve 38 by which raising and lowering of the antenna is regulated.

A cylindrical casing 33 is provided, in which the antenna is housed when retracted. Within the tubular casing pressure changes developed in the intake manifold of the engine are made to act upon a piston to move the aerial. The casing assembly may be mounted to project through any suitable portion of the sheet metal sheathing of the vehicle body. In the shown arrangement it is hung from the cowl portion 22 at one side of the passenger compartment. When so positioned it is preferably located within the space between the inner and outer sheathing of the body. The upper end of the antenna casing is reduced in diameter and projects through the cowl, as shown in Figure 1, so that the antenna when extended projects. above the car body, as indicated in dotted lines in Figure 1.

The details of construction of the antenna assembly are best shown in Figure 2. The cylindrical casing 33 is preferably a sheet metal tube, of aluminum or the like, having a smooth interior surface and forming a cylinder which is closed at its bottom by a cupped closure 35, and at its top by a head assembly comprising a body portion 31 formed of hard rubber or other suitable insulating material. The heads 35, 31 may be screwed into the tube 33, as shown. A bore 38 in the head 31 is axially aligned with the cylinder 33 and guides a tubular antenna element 40, which at its lower end is attached to an actuating piston assembly. The piston assembly comprises two rigid sections designated 4|, 42 having slidably interfitted central portions and formed of hard rubber, plastic, or other suitableinsulating material. Between the rigid sections 4|, 42 and spaced from the rod by the interfitted central portions thereof is a soft packing member 43, of oil-treated leather or the like, adapted to provide a tight seal with the Wall of the tube. The packing disc 43 is compressed between the discs 4|, 42 by a spring 44 reacting against the discs and against an abutment pin 46 carried by the end of the piston rod portion upon which the piston assembly is mounted. Rod 45 will be seen to comprise an extension of the tubular antenna element 48, to the end of which it is secured by interfitting groove portions 41.

Two packing glands or stuffing boxes are provided in the head 31, one near the bottom and the other near the top of the passage 38 through which the aerial extends. The lower gland is generally designated 50, and is provided with a spring 5| which constantly tends to tighten the packing. A similar gland is mounted in the nut by which the assembly is secured in place, the packing spring 56 being housed partly in the nut and partly in the counter-bored upper extremity 39 of the bore 38. Thus the stuffing boxes are so located that one is outside the body and the other inside the body when the aerial is installed.

The tubular casing is adapted to be grounded to the vehicle body or chassis, as by the wire 34, and the shielding efiect is continued upwardly to juncture with the cowl 22 by means of a sheet metal shield cap 62 fitted over the head 37. Above and below the cowl 22, upon the reduced neck portion of the head, soft rubber fillers 64, 65 are arranged in such manner that they are compressed when the nut 60 is tightened, and seal the aperture in the cowl through which the antenna assembly projects. A collar 66 above the top filler, 64, finishes the exterior and transmits the compressive eiiect of the nut, the reaction being taken against a shoulder 68 formed by the reduced diameter of the upper extremity of the head assembly. Collar 66 is also preferably of insulating material.

The bore 38 will be seen to fit the antenna snugly only at its upper end, adjacent the upper stuffing box 55, the rest of the bore being enlarged to provide substantial clearance around the antenna element throughout the greater part of the distance between the two stuffing boxes. An aperture, 18, is formed in the side of the head 37, and its cap 62, to provide communication between the bore 38 and the space beneath the cowl. This opening is large enough to prevent reduction of pressure in the passage 38, and thus breaks any vacuum which might otherwise exist in the passage 38 due to leakage through the stuffing box 58, and accordingly prevents any tendency to draw water or other foreign matter through the upper stuffing box. This opening is of course in a protected position, and will be seen to provide an escape for any water which might find its Way through the upper stufi'ing box-although such leakage is almost impossible, in view of the equalized pressure which exists upon the two sides of the stufiing box 55.

Slidable in the antenna element 40 is a manually operable extension 48, which also may be of tubular construction. To the upper end of the extension a ball 49 is attached, forming both an ornament and a convenient handle by which the extension may be grasped and pulled out or pushed into the main antenna element 40 at will. Frictional and electrical contact between the extension section and the main antenna tube 48 is provided by bifurcating the end of the extension section, as indicated at 12, and stressing the arms thus formed outwardly in such manner that they tend to expand against the interior of the antenna tube 40. The extremities of the arms may also be rounded, as indicated at 13,

to insure smiooth wiping engagement, and their expanding, effort may be reinforced. by a rubber block 14, trapped between the arms in the space.

provided by the outwardly rounded sections, such rubber block acting as a spring for this purpose.

Electrical contact with the antenna assembly is furnished by spring brush fingers 15 carried by a supporting ringllmounted in the head 31, and loosely encircling the antenna. The ends of the spring fingers 15 which engage the antenna are curved about a shorter radius .than that of the antenna tube 40, to provide reduced areas of engagement, and increase the unit pressure between such fingers or brush members and the antenna rod. Brushes 15. may be formed of phosphor bronze, and undue wear of the rod is prevented by plating it with a hard chromium plating. This arrangement will be seen not only to provide materials of high conductivity, but to allow substantial pressure between the brushes and the antenna, so that imperfect connections cannot develop. The brush-supporting ring 1'! is held by a hollow stud 80, threaded thereinto and projecting radially through the side of the antenna casing. Stud 80 serves as a binding post, the antenna lead-in wire 8| being connected thereto. The stud isinsulated from the portions 62, 33 of the casing assembly by means of insulating- washers 82, 83. The hollow post or stud80 and the connected end of the lead-in assembly will be seen to be housed in a shield can 85, from the s'ide of which the lead-ihwire extends to connection with the radio apparatus (unshown), through shielding loom 81, which is also suitably grounded.

The inner end of the hollow post 80 communicates with the space above the piston in the cylinder '33, and a rubber tube or other conduit 90 is connected to the projecting outer end of the post, and extends through an opening in is effected by means of a valve, the casing of which is generally designated 30, mounted upon the instrument panel of the vehicle and constructed in such manner that'the vacuum line 95 to the intake manifold is normally closed, but may be connected at will, by movement'of the valve, toeither of the'tubes 90, 94, the former connected to the nipple 80 andthe latter to the nipple 92, as previouslydescribed' The valve body is designated 91, andwill be'seen to be normally centered in the valve casing 30 by means of springs IOI, I02, arranged one at each end of the valve body.- A stem I03 and knob I04 attached to the valve body enable the same to be moved at will by the operator against the efiort of the springs; Nipples I06, I01 and. I08 afford connection to the interior of the valve casing, their inner openings being .adapted to be selectively connected by.means of a slot H in the valve body. Travel of thevalve is limited by a pin and slot connection I,II,'. II2. Vent apertures II 3, II4uare. provided in thelcasing at,

each endlof the valve, so that when the tubes 90, 94 which are connected to each end of the cylinder are not connected to the intake manifold, they are vented to atmosphere. The pressure differential due to the vacuum normally existing in the intake manifold tends to draw the valve tightly against the side of the valve casing nearest nipple I01, and so seal the line 95, while the slot H0 is of such length and so positioned that it may bridge only the distance required to connect either of the tubes 90, 94 to the vacuum line, 95.

It will be seen that when the valve is pushed in by means of the knob I04, connection of the vacuum to the tube results in a reduction of pressure within the cylinder-.33 (while the space below the piston remains connected to atmos- The phere through the tube 94 and vent II I). antenna assembly is thereforelifted. When the valve is released it immediately resumes the centered position shown in Figure 6, and the antenna assembly is held in whatever position it may then be in, by the friction imposed by the stuffing boxes, brushes 15, and piston assembly. Lowe ering of the antenna assembly is effected in like manner by pulling the valve .down to connect the vacuum line to tube 94. This will be seen to effect a reduction of pressure below the piston, and to draw the piston assembly down and return the aerial to the lowered position in which it is shown in full lines in Figures 1 and 2.

In the modified construction shown in Figures 8, 9 and 10, in which parts equivalent to those already described have been given corresponding reference numerals distinguished by the addition of the letter A to each, the tubular sheet metal casing 33A is adapted to be supported in similar fashion, to project through the cowl 22A or other suitable portion of the vehicle. The casing 33A is grounded in similar fashion to act as a shield, and the telescoping aerial portions 40A, 48A are extensible therefrom. In this embodiment, however, the inner or extension antenna section 48A is also equipped at its lower end with piston sealing means, 433, while the piston assembly (generally designated 43A) of the outer extensible aerial section 40A, is provided with a central aperture I25 extending therethrough to afford pressure communication permitting direct actuation of both sections of the antenna by pressure changes transmitted to the area below both the pistons, through coupling means 92A and conduit I26 connected thereto.- The coupling assembly will be seen to form a closure for the lower end of the cylinder.

The piston means 43A is constructed to insulate the antenna assembly from the casing atthe lower end, while at the upper end of the assembly insulation is also provided by a sleeve 31A and insulating washer 31B of suitable material. At its upper end the aerial is secured in place by a nut 60A containing a packing gland 55A which serves to seal the tubular antenna section 40A with respect to the cowl in a manner to prevent infiltration of water. A vent 10A is also provided in the side of the casing tube 33A above the piston assembly but inside the body. This vent is of ample size to break any vacuum which might otherwise develop above the pistonv assembly 43A upon descent of the latter, thus preventing any tendency to draw water through the packing gland.

The central or extension antenna section48A is sealed with respect to theouter section 40A by means of a second gland I55, anda vent I10 is formed in the side of the antenna tube MA at a point which lies below the gland 55A when the aerial is fully retracted, air passages I60 being formed in the insulating sleeve 31A to provide free communication between vents 79A and H when the aerial sections are retracted. The arrangement is such that when pressure is applied to the lower end of the casing, both pistons are raised at once, the extension section remaining fully retracted into the outer section until the latter is fully raised. When the outer section 40A has risen to its full height, however, continued pressure forces the central section outwardly to raise the extension. During the first stage of this double extension, the air above piston assembly 43A escapes through vent A, while during the second stage air above piston assembly 43B escapes through vent I10. When the pressure in the lower part of the casing is lowered sufficiently to cause retraction of the antenna sections, both sections first fall at once carrying the vent I10 down into the casing and below the gland 55A before the extension section 48A moves inwardly with respect to the outer section 40A. Accordingly no air is drawn into the space above piston assembly 433 until such air can enter from within the vehicle body through vent 10A and communicating passages I60. During the first stage of the downward movement air of course enters the space above the piston assembly 43A through the vent 10A.

The pressure changes by which both sections of the antenna are projected and retracted are generated in a special pressure cylinder I21, to which conduit I26 is connected. A piston I30 in the pressure cylinder is operable in response to pressure changes induced in a larger vacuum cylinder I33, attached at one end to the pressure cylinder in co-axial relation therewith. A rod I34 connects piston I30 to a larger piston I35 in the vacuum cylinder, and conduits 90A, 94A, connect opposite ends of the vacuum cylinder to the nipples IUBA, I08A, respectively of the control valve, the casing of which is generally designated 30A.

The valve may be constructed similarly to the valve disclosed in connection with the first described embodiment, the central nipple IU'lA thereof being connected to the intake manifold I SA of the engine IZA, by means of a vacuum conduit 95A. When the knob IBSA of the valve is pushed up, conduit 95A is connected to the vacuum line, and the reduction of pressure at the left side of piston I35 (as viewed in Figure 10), forces that piston to the left, and with it the piston I30. This increases the pressure in cylinder I21, and accordingly in the space within cylinder 33A below both pistons. Both antenna sections are thus forced outwardly, to project them above the vehicle body to any desired extent, in accordance with the increase of pressure. Air above the piston 43A, 43B is allowed to escape through vents I40, I4I. When the valve is pulled down, reduction of pressure to the right of piston I35 draws piston I30 in the same direction, reducing the pressure in cylinder I21 and in the connected spaces below the pistons 43A, 43B, which are thus drawn into their respective tubes to retract the antenna sections.

As shown in Figure 8, the pressure and vacuum cylinder assembly may be mounted principally in the engine compartment, as by supporting the same from the dash of the vehicle, the arrangement being shown as such that only the end of the pressure cylinder projects into the passenger compartment to a point adjacent the aerial. It will be recognized, however, that with this arrangement, the aerial might be located at a remote point, to project through the roof of the vehicle, for example, or at any other desired point. It will also be recognized that more than two extensible sections could be provided in like fashion. Extreme compactness is secured, in practical fashion, by reason of the fact that it is possible to project and retract all sections by the power-operating means, and the increased pressure provided by the booster unit consisting of the pressure and vacuum cylinders, permits use of antenna tubes of smaller diameter than could be operated directly by the vacuum developed in the intake manifold, at least against the drag imposed by effective sealing means.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiments to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

What I claim is:

1. A radio aerial construction adapted to be supported within a vehicle body portion, comprising a casing assembly including a metallic tube, an insulating head portion closing the upper end of said tube, means for supporting said casing assembly with its upper extremity extending through and above a vehicle body portion, and with said insulating head portion projecting above and below the material of the body portion, said head having a passage extending longitudinally therethrough, an antenna element slidably extending through said passage and movable inwardly and outwardly with respect to the casing assembly but insulated therefrom by said head portion, piston means connected to an inner end of said antenna element Within the tube to actuate and guide the same, said inner end of the antenna element also being insulated from the tube, means for directing fluid under pressure against said piston to actuate the antenna element, stufling means located near the top of the casing assembly but below the portion of the body portion through which the assembly projects, for sealing the antenna element with relation thereto, and a vent connecting the exterior of the casing assembly with the passage in the head through which said antenna element extends, said vent being located below said portion which is adapted to extend through the vehicle body, whereby the pressures in said passage above and below said portion of the vehicle body may be neutralized.

2. A radio aerial construction adapted to be supported within a vehicle body, comprising a casing assembly including a metallic tube and a head portion closing the upper end of said tube, means for supporting said casing assembly with its upper extremity extending through and above a vehicle body, and with said head portion projecting above and below the material of the body, said head portion having a passage extending longitudinally therethrough, an antenna element slidably extending through said passage and movable inwardly and outwardly with respect to the casing assembly, pressure-operable means for actuating said antenna element, stuffing means located near the top of the casing assembly but below said portion thereof which is adapted to project through the vehicle body, for

sealing said antenna element with respect to said passage and thereby with respect to the easing assembly, and a vent portion connecting the exterior of the casing assembly with said passage in the head, said vent also being located below said portion which is adapted to extend through the vehicle body, whereby the pressures in said passage above and below said portion of the vehicle are not influenced by' the pressure within the casing assembly below said stuffing means.

3. A radio aerial construction adapted to be supported within a vehicle body, comprising a casing assembly including a metallic tube and an insulating head portion closing the upper end of said tube, means for supporting said casing as-- sembly with its upper extremity extending through and above a vehicle body, an antenna element slidably extending through said head portion and movable inwardly and outwardly with respect to the casing assembly but insulated therefrom by said head portion, piston means also formed at least partly of insulating to juncture with the vehicle body.

5. In an aerial construction as set forth in claim brush contact means carried by said head portion and wipingly engageable with said antenna element, and lead-in contact means extending through and insulated from the grounded portions of said casing assembly and connected to said brush contact means.

6. In an aerial construction as set forth in claim 3 brush means carried by said head portion and wipingly engageable with said antenna element, lead-in contact means extending through and insulated from the grounded portions of said casing assembly and connected to said brush means, said means comprising a hollow connector opening at its inner end at a point in communir cation with the interior of said casing assembly above said piston, and means for connecting a pressure-conducting conduit to the exterior of said connector.

7. In an aerial construction as set forth in claim 3, brush means carried by said head portion for providing electrical contact with said antenna element, a hollow metallic connector extending through and insulated from the grounded portions of said casing assembly and electrically connected to said brush means, the innerend of said connector opening at a point in communication with the interior of said casing above said piston, said brush means being supported by the inner end of said connector, and means for making electrical and pressure connections to the outer end of said connector.

8. In an extensible and retractible radio aerial, a plurality of telescoping sections, a substantially pressure-tight casing enclosing the lower end of the outer section, and means for applying variant pressures to said casing to enable selective projection and retraction of said sections,

comprising a vacuum cylinder having connections at opposite ends thereof and a piston adapted to travel thereinbetween said connections, a pressure cylinder arranged substantially coax- -ially withrespect to said vacuum cylinder and of smaller diameter, a piston in said pressure cylinder, means providingmechanical connection .between said pistons; means providing pressure communication between the pressure cylinder and said casing, and valve means for selectively connecting said connections of the vacuum cylinder to a source of variant fluid pressure.

9. In a pressure-operated aerial construction, in combination with a tubular casing adapted to be mounted in a vehicle body, said casing having a head portion adapted to project through and above the sheathing of the body, said head portion having a longitudinal passage therein, an

antenna element slidable in said passage inwardly and outwardly of the casing to project to varying extent from a body in which the aerial is installed, two stufflng means in said passage, one arranged above and the other below said portion of the head which is adapted to project through the sheathing, said passage having a vent located at a point above the lower stufiing means but below said portion adapted to project through said sheathing and connecting said passage to the exterior of the casing.

10. In an aerial construction as set forth in claim 3, electrical coupling means carried by said head portion and adapted to conduct high frequency energy between said antenna element and desired radio apparatus or the like, lead-in terminal means connected to said coupling means and adapted to be connected to such radio apparatus or the like and extending through and insulated from the grounded portions of said casing assembly, said lead-in terminal means comprising a hollow connector opening at its inner end at a point in communication with the interior of said casing assembly above said piston, and means for connecting a pressure-conducting conduit to the exterior of said connector.

11. In an aerial construction as set forth in claim 3, electrical coupling means carried by said head portion and adapted to conduct high frequency energy between said antenna element and desired radio apparatus or the like, a hollow metallic connector extending through and insulated from the grounded portions of said casing assembly and electrically connected to said electrical coupling means, the inner end of said connector opening at a point in communication with the interior of said casing above said piston, said electrical coupling means being supported by the inner end of said connector, and means for making electrical and pressure connections to the outer end of said connector.

12. A radio aerial construction adapted to be supported by a vehicle body and to project through a portion thereof, comprising a casing assembly including a tubular housing, a head portion substantially closing the upper end of said housing but having a passage therein adapted to slidably receive an antenna element, means for supporting said casing assembly with the upper end thereof extending through and with said head extending above said vehicle body portion, an antenna element slidably extending through said passage in the head portion and movable inwardly and outwardly with respect to the. tubular housing and insulated from the vehicle body, packing means operatively engaging the antenna element and the housing and located between said passage and the interior of the housing to resist entrance of moisture into the housing along the antenna element, and vent means connecting said passage at a point above to said passage along the antenna element, to said packing means to the exterior of the casing prevent reduction of pressure at the upper end of assembly below that portion thereof which prosaid passage which communicates with the exjects through the vehicle body portion, whereterior of the body.

by said vent breaks any reduction of pressure Within the housing which may be communicated CARY W. MARTIN.

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