Telescopic rod antenna

Dec. 18, 1945.

2,391,202

F. TELLANDER ET AL

TELESCOPIC ROD ANTENNA.

Filed May 15, 1943

Sheets-Sheet 1

<img file="US2391202A_D0001.tif" />

<img file="US2391202A_D0002.tif" />

F. TELLANDER ET AL

2,391,202

TELESCOPIC ROD ANTENNA

Sheets-Sheet 2

Filed May 15, 1943

<img file="US2391202A_D0003.tif" />

Dec. 18, 1945

2,391,202

F. TELLANDER ET AL

TELESCOPIC ROD ANTENNA

Filed May 15, 1943

Sheets-Sheet 3

<img file="US2391202A_D0004.tif" />

Patented Dec. 18,1945

2391,202

UNITED STATES PATENT OFFICE e

2,391,202

TELESCOPIC ROD ANTENNA

Frederic Tellander, Franklin Park, and Otto E. Wagenknecht, Chicago, Ill., assignors to Zenith Radio Corporation, Chicago, III., a corporation of Illinois

Application May 15,1943, Serial No. 487,088

Claims.

This invention relates to telescopic rod antennas and has for its principal object to provide an improved antenna of the type which will automatically project and retract at the desire of the operator.

In accordance with our invention we provide a telescopic rod antenna constituted of a plurality of telescopic sections. The sections are provided with means whereby they are held against relative rotation in all their positions. All the actuated sections are provided with a nut at or adjacent their lower ends, which nuts are adapted to be engaged and actuated in turn by a screw which is rotatably mounted within the lower section. The screw terminates somewhat above the bottom of the lowermost section and it is connected to a rod of lesser diameter which extends downwardly below the lowermost section and is driven in suitable manner in either direction, for example by means of a reversible motor.

When the actuable sections are fully retracted, the nut of the uppermost actuable section is clear of the lower end of the screw and bears against it reslliently. At the end of the retracting operation the end of the screw cooperates with the nut of the uppermost actuable section to provide a clicking noise which indicates to the operator that the antenna is fully retracted so that he should stop the motor. When the motor is started in the proper direction, the nut of the uppermost actuable section threads onto the screw and the uppermost section is elevated.

To Insure that only one section at a time shall be actuated outwardly, we prefer to provide between the second and third sections and between the third and fourth sections and so on, means providing friction of progressively greater degree. Thus, the first said friction means prevents the second actuable section from being carried up with the first actuable section until the first actuable section is projected to full extent relative to the second actuable section. When this occurs the nut of the second section is brought into engagement with the lower end of the screw and the friction means between the second and third sections is overcome and the second section is projected upwardly. The lower friction means, providing greater friction, maintain all the sections below the second actuable section in their initial position until the second section is fully projected. Thereupon the third section is engaged by the screw and is forced outwardly and so on until the antenna is fully projected.

When the antenna is fully projected, the nut of the second section from the bottom engages the (Cl. 189—28) toP of the screw and, being reslliently pressed against the screw so as to be In readiness to be rethreaded upon the screw when the screw is reversely rotated, and a clicking noise is again provided to indicate to the operator that the projection of the antenna is complete and that he should turn off the motor.

Since a lower nut is brought into engagement with the lower end of the screw shortly before the next higher nut disengages the screw, it is preferred, in order to prevent any possibility of jamming, to provide a certain degree of freedom between the nuts, that is, a degree of freedom which enables the lowermost nut to remain stationary for a short period of time until it properly engages the rotating screw.

This degree of freedom is provided in one embodiment of our invention by allowing the nuts to move longitudinally with respect to their sections, springs being provided to maintain the nuts in a normal position on their sections. In another embodiment of our invention we mount the nuts rigidly on their sections and provide an extensible screw shaft to ensure proper engagement of the nuts therewith. In still another embodiment of our Invention we provide resilient means between adjacent sections so as to permit slight displacement of the nuts at the time of engagement with the screw.

It will be understood that the same degree of freedom or resilience is effective when the nuts are engaged at the upper end for retraction of the antenna which engagement occurs before the next lowermost nut is disengaged by the screw.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. The present invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof may best be understood by references to the following description taken in connection with accompanying drawings in which:

Figure 1 is an elevatlonal view of our antenna mounted in the cowl of an automobile, which cowl is shown in section;

Fig. 2 is a longitudinal section through one embodiment of our Invention, the intermediate part of the antenna being omitted;

Fig. 3 is a sectional detail taken on the line 3—3 of Fig. 2;

Fig. 4 is a sectional detail taken on the line 4—4 of Fig. 2;

Fig. 5 is a sectional detail taken on the line S—3 of Fig. 2;

2,391,302

Fig. 6 shows an elevational view of a modified form of our antenna mounted on the exterior of a vehicle such as a tank and provided with a resilient mounting to enable the vehicle to pass beneath branches of trees and other overhead obstructions without injury to the antenna;

Fig. 7 is a fragmentary sectional detail of a modified form of our antenna employing a resilient screw;

Fig. 8 is a longitudinal section of another antenna embodying our invention; and

Fig. 9 is a diagrammatic view showing the manner in which our improved antenna may be mounted on the roof of an automobile.

Referring to the drawings, and particularly to Figs. 1 to 5 inclusive, our improved collapsible rod antenna comprises a plurality of tubes In telescopic relation. The lowermost tube 10 cooperates with an inner tube 11 which in turn cooperates with a still smaller tube 12. The tube 12 telescopically receives the tube 13. These tubes are in the retracted condition of the antenna located around an inner screw 14 in the manner shown in Fig. 2.

The upper ends of the tubes 10, 11 and 12 are provided with reduced necks 15 which provide frictional sliding support for the tubes 11,12 and 13, respectively. The tubes 11, 12 and 13 are provided with enlarged lower ends 16 which are arranged to have a sliding fit in the major portions of the tubes 10, 11 and 12, respectively. The tube 10 has an enlarged end 17 which is received rigidly In a suitable support 18.

In order to limit the projection of the tubes 11, 12 and 13, relative to the tubes 10, II and 12, respectively, the tubes II, 12 and 13 are provided at elevated positions thereon with enlargements 19 which are arranged, in the extended condition of the antenna, to engage the shoulders provided by the necks 15. In the case of the tube II, the projection 19 is shown as the upper part of the enlarged lower end 16.

Each of the tubes II, 12 and 13 carries at its lower end a nut 20 which is threaded operatively to receive the screw 14. The screw 14 is carried on the upper end of a reduced unthreaded shaft 21 and when the antenna is fully retracted, as shown in Fig. 2, the nuts 20 are located below the threaded portion of the screw 14 with the nut 20 of the tube 13 in contact with this threaded portion.

The shaft 21 is supported by a double thrust bearing 22 mounted in the support 10. Means are provided for preventing relative rotation between the tubes 10, II, 12 and 13. For this purpose the main portions of the tubes 10, 11 and 12 are provided with vertical flutes 23 (Figure 5) and the enlarged portions 16 of the tubes II, 12 and 13 are each provided with corresponding vertical flutes 24 (Figure 4) in such manner that they receive first said flutes respectively.

The nuts 20 are provided with vertical recesses or flutes which receive the flutes of the enlarged portions 16 which carry the nuts, thus providing for limited relative longitudinal movement between each nut and the tube which carries it while preventing relative rotation between the nuts and the tubes.

In the case of tubes II and 13, the nut 20 is forced resiliently downwardly by means of a coil spring 25, the lower end of which bears against the nut 20. The upper end of each spring 25 abuts against a washer 26 located within the enlarged portion 16 of the tube.

In the case of the tube 13, the washer 26 bears against an annular shoulder 17 which may suitably be rolled in the enlarged portion 20. In the case of the tube II, the washer 20 may suitably bear against a C spring 28 which has portions projectS ing through openings in the enlarged portion 16 (Figure 3) of the tube II.

The nut 20 of the tube 12 is resiliently supported by two coil springs 20 and 30 so that it is free to move in either direction relative to the 10 tube 12. The coil spring 30 abuts against the lower end of the nut 20 of the tube 12 and against a shoulder rolled on the lower end of the enlarged portion 10 of the tube 12.

The coll spring 29 bears against the upper side IS of the nut 20 and against a collar 31 slidably mounted in the enlarged portion 10 of the tube 12. The collar 31 is adapted to make contact with a C spring 32 which extends through openings in the enlarged portion 10 of the tube 12 in the same 20 manner as the C spring 28 (Figure 3) extends through openings in the enlarged portion 16 of the tube II. The collar 31 is provided with an upwardly directed reduced sleeve portion 33 which Is adapted to project upwardly through 25 the C spring 32 and to engage the lower end of the enlarged portion of the tube IS in the manner shown in Fig. 2.

When the antenna is fully retracted, as shown in Fig. 2, all the nuts 20 are located below the 30 threaded portion of the screw 14, the nut 20 of tube 13 bearing against the lower end of the threaded portion of the screw under the combined action of the springs 20 and 30 which are compressed. It will readily be understood that when 35 the screw I* is rotated in the clockwise direction as viewed from above (assuming that it has a right-hand thread), it will pick up the nut 20 of the tube 13 and that tube will be projected outwardly relative to the other tubes until its nut 20 40 runs off the upper end of the screw 14.

Means are provided to ensure that the other nuts 20 are not engaged by the threaded portion of the screw 14 before the tube 13 has been projected to full extent relative to the tube 12 and ⁴⁵ likewise means are provided for ensuring full projection of the tube 12 before movement of the tube II. This object is attained by providing progressively increasing friction between tubes 13 and 12, between tubes 12 and II, and between 50 tubes II and 10, in that order. This friction is suitably attained by the provision and proper design of the C springs 32 and 20. When the tube 12 starts to move up, the C spring 32 carried by it engages the inner shoulder provided by the upper 55 end of the enlarged portion 16 of the tube 11 and it is only when the tube 12 is positively driven upwardly that the friction provided by the C spring 32 is overcome.

The C spring 28 provides still greater friction •0 and it is only when the tube 12 is projected to full extent that the tube II starts to move up. The C spring 28 is arranged to engage the inner shoulder provided by the upper end of the enlarged portion 17 of the tube 10.

The screw 14 is of such length that the nut 20 of the tube 12 is engaged by it before the nut 20 of the tube 13 clears the screw 14 and the nut 20 of the tube 11 is engaged before the nut 20 of the tube 12 clears the screw 14.

⁷⁰ Assuming that the antenna is in the fully retracted condition as shown in fig. 2 and that the screw 14 is driven in clockwise direction as viewed from above, it being a right-hand screw, the tube 13 is projected out of the tube 12. If the friction between the tubes 13 and 12 tends

2,301,202 to move the tube 12 up at the same time, the C spring 32 is brought into contact with the inner shoulder of the enlarged portion IS of the tube

11, and if the tube II tends to move upwardly as a result of the upward movement of the tube

12, the C spring 23 is brought into engagement with the corresponding shoulder on the enlarged portion II of the tube 10.

Consequently, only the tube 13 is projected and this projection continues until the enlargement it of the tube 13 engages the inner shoulder provided by the neck IS of the tube 12., Thereupon the tube i2 is positively drawn upwardly by the tube 13. The nut 20 of the tube 13 is still engaged by the screw 14 and this engagement continues until the nut 20 of the tube 12 Is brought into engagement with the lower end of the screw 14. Consequently, the screw 14 threads into the nut 20 of the tube 12, the spring 30 permitting a slightly downward displacement of this nut 20 to enable its proper engagement with screw 14.

Both the nuts 20 of the tubes 13 and 12 are in engagement with the screw 14 and as the rotation of the screw continues, both the tubes i3 and 12 are projected upwardly. After the nut 20 of the tube 13 runs off the screw 14, the screw projects the tube 12 upwardly and the tube 13 is carried up with it owing to the frictional engagement between the tubes 12 and 13.

The projection of the tube 12 continues until Its projection 19 engages the shoulder provided by the neck 16 of the tube II. When this happens, the tube 11 is positively moved upwardly by the tube 12 and the nut 20 of the tube II is brought into engagement with the lower end of the screw 14. In the event that this nut 20 is not presented correctly to the screw 14, the nut 20 of the tube 12 may move up slightly relative to the tube 12 against the action of the spring 29, thus permitting the screw 14 to pick up the lowermost nut 20 on tube 11.

The nuts 20 of the tubes 12 and II are thus driven together by the screw 14 until the nut 20 of the tube 12 runs off the upper end of the screw 14. Thereafter the tube II is driven upwardly by the screw 14 and the tubes 13 and 12 are carried upwardly owing to the frictional engagement between the tubes 13 and 12 and 12 and II.

During the upward projection of the tube It. the lower spring 25 is compressed slightly by the friction of the tube 11 with the tube 10 acting on one side of the spring 25 and the drive of the lowermost nut 20 by the screw 14 acting on the other side of the spring 25. Consequently, when the tube I i is fully projected, the lower spring 25 is under some compression and as the screw 14 continues to rotate, the lowermost nut 20 slips on the end of the thread at the upper end of the screw 14 in the manner which provides an audible signal that full extension of the antenna has been attained, and maintaining the nut 20 of tube 11 ready for rethread on screw (4 when that screw is reversely rotated.

In order to retract the antenna, the screw 14 is rotated in the opposite direction and since the nut 20 of tube 11 is pressed downwardly towards the upper end of the screw by the lower spring 25, the nut 20 of the tube 11 is engaged by the screw 14 and the tubes II, 12 and 13 are initially moved downwardly as a unit. Before the nut 20 of the tube II clears the lower end of the screw 14, the nut 20 of the tube 12 is brought into engagement with the upper end of the screw and becomes engaged thereby. If there is a slight upward movement of the nut 20 of the tube 12 by the screw 14 due to the fact that the threads on nut 20 of tube 12 are not exactly in cooperating relationship with the threads on the screw 14 when such nut Initially engages the screw, this 5 slight movement is permitted by compression of the spring 20 whereby such nut 20 may be threaded on the screw without jamming.

Shortly after the engagement of the nut 20 of the tube 12 by the screw 14 and subsequent 10 threading thereon, the nut 20 of the tube II clears the lower end of the screw 14 and the C spring 20 is engaged by the lower end of the tube 12 to effect downward movement of the tube II.

The nut 20 of the tube 12 is moved downwardly by the screw 14 but before it reaches the lower end of the screw, the nut 20 of the tube 13 is engaged by the upper end of the screw. If the nut 20 of the tube 13 is not properly presented 20 to the upper end of the screw for ready engagement, the nut 20 of the tube 12 continues to move downwardly slightly against the action of the spring 30 and moves tube 13 downwardly, the nut 20 on tube 13 moving slightly upward against 25 the action of upper spring 25 until proper engagement of nut 20 on tube 13 with screw 14 is obtained whereby the latter nut is prevented from jamming. Thereafter the nut 20 of the tube 13 is moved downwardly by the screw 14 30 until it clears the lower end of the screw. Before doing so, the lower end of the tube 13 engages the sleeve 33 and the tubes 12 and 11 are positively carried down by the downward movement of the tube 13.

When the nut 20 of tube It clears the lower end of the screw 14, it is biased upwardly by the springs 29 and 30 which are under compression and consequently as the screw 14 continues to rotate, the nut 20 of the tube 13 is recipro40 cated upwardly and downwardly against the end of the thread of the screw 14, giving an audible signal which indicates that full retraction has been attained and maintaining the nut 20 of tube 13 ready to rethread on screw 14.

it will be understood that all the nuts 20 may be mounted in their sections similar to the mounting provided for the second nut from the bottom in Fig. 2, or the nuts may all be mounted with the aid of a single spring 25 as shown In 50 the two extreme nuts of Fig. 2. If only single springs are employed with all nuts 20, it is, in some cases, possible, by manual interference, to overload the motor because nuts may start to thread on screw 14 so as to jam. If only the 55 spring 25 is used on tube 12, and if tube 13 is manually pressed down so as to fully compress spring 25 of this tube, then nuts 20 of tube 13 and 12 may jam, because no relative movement can take place between them. On the other 60 hand, if spring 30 is used, then even if spring 25 of tube 13 is fully compressed due to manual interference, spring 29 or 30 will yield to provide for relative movement between nuts 20 of tubes (3 and 12. With the double springs 29 and 30, ⁶⁵ the motor is not thus overloaded, since the compression of one spring Is opposed by the compression of the other spring and the displacement of a nut supported by the double springs is not accompanied by an increase of compression as 70 is the case with single springs.

Our improved antenna may be provided with a manually operable section or sections. Thus, as shown in Fig. 2. we may mount on the upper end of the tube 13 through spring 37 a socket 34 75 which frictlonally receives a rod 35 one end of

9,391,soa spring 37 being fastened in socket 8* and the other end of spring 37 being secured in socket 27 which, in turn, is secured on tube 13. The rod 36 carries at its upper end a knob 36 whereby it may be manually pulled out from the socket 34. The screw 14 may suitably be made hollow so that the rod 35 may be telescoped thereinto. The rod 35 and the socket 34 are provided with complementary shoulders to prevent complete withdrawal of the rod 35 from the socket 34.

Since the rod 35 will normally provide a very high antenna, it is preferred to provide a resilient mounting of the socket 34 upon the tube

13. Thus, we may connect the socket 34 to the upper end of the tube 13 by means of a closewound spring 37 rigidly connected to both the socket 34 and the socket 27 on tube 13.

Consequently, if the rod 35 strikes a high obstruction, the spring 37 can flex to enable the antenna to pass under the obstruction without injury thereto. To enhance the action of the spring 37, and keep it under compression with its colls flat together, we prefer to provide within it a coil spring 38 under considerable tension and having its ends secured to the socket 34 and to the tube 13.

The screw 14 may suitably be driven by a reversible motor 39 which is connected thereto by means of an insulating coupling 40. Our improved antenna may be mounted in any suitable location and is particularly suitable for use on automotive vehicles. In Fig. 1 is shown the preferred manner of mounting the antenna for use on an automobile. The tube 10 is supported on the cowl 41 of the automobile by means of an insulating bushing 42. The lower end of the tube 10 is supported by means of an insulating bushing 43 on a bracket 44 carried by the vehicle adjacent the floor level. When this manner of mounting is employed, an insulating lead-in wire 45 is connected to an elevated position on the tube 10 and a grounded shield 46 is arranged around the portion of the tube 10 inside the vehicle.

In the embodiment of the invention shown in Fig. 7, the screw 14' is constituted by a stout coil of wire which is rigidly mounted on a rod 46'. This rod is carried at the upper end of a smaller rod 21 which is driven in the manner described in connection with the last-described embodiment. The extremities of the coil 14' extend beyond the rod 46' so that these portions of the screw are relatively resilient. The nuts 20 in this embodiment are conformed to cooperate with the coil screw 14’, and are rigidly mounted at the lower ends of their sections.

As shown in Fig. 7, the uppermost nut is in engagement with the lower end of the screw 14' when the antenna is fully retracted. This lower end is then slightly compressed. When the rod 21 is driven in the proper direction, the uppermost nut 20 meshes with the screw 14' and the uppermost actuable section is consequently driven upwardly. The next two lowermost sections are held by the springs 28 in the same manner as in the first described embodiment, until the shoulder of the uppermost actuable section engages the corresponding shoulder of the next lowermost section and elevates that next lowermost upwardly into engagement with the screw 14'.

As in the previously described embodiment, the second nut engages the screw 14' before the first nut is disengaged, and so forth. At the time of the engagement of the second nut of the screw 14', the distance between the two nuts engaging the screw is determined by the location of the nuts and the shoulders on the 5 sections. The resilience of the ends of the screw 14’ provides such change of dimension as may be necessary for the proper engagement of the engaging nut. That is, the resiliency of the screw 46' permits a slight collapse of the resilient screw 10 46' to enable the end of the screw to have threaded thereon a cooperating nut without jamming, Such collapsing of the screw takes place when the nut is improperly presented to the screw either at its upper or lower ends.

In this embodiment of the invention the sections may be held against relative rotation as in the first described embodiment of the invention, but the sections may be provided with sufficient resistance to rotary movement to enable 20 the nuts to be engaged and disengaged without providing flutes or other means for holding the sections against relative rotation.

In the embodiment of the invention shown in Fig. 8, the nuts 20 are rigidly mounted at the 25 lower ends of the sections and springs 47 are provided between a shoulder 48 near the lower end of an upper section and a shoulder 48 near the upper end of the next lowermost section. It will readily be understood that when the nut of 30 an upper section is near the upper end of the screw 14 and has carried the next lower nut into engagement with the lower end of the screw 14, the spring 47 is compressed slightly until the lowermost nut starts threading on the screw. 35 Likewise, during retraction of the antenna, an upper nut is brought into engagement with the upper end of the screw before the next lower nut is disengaged and the spring 47 is again slightly compressed until the upper nut starts onto the 40 upper end of the screw. In this embodiment of the invention, a spring 50 is provided at the bottom of the lowermost section. When all the sections are retracted, the lower ends of the sections 13 and 12 bear against the friction springs 45 28 of the sections 12 and II respectively, or rigid means carried by the sections 12 and II respectively, and the lower end of the section 11 bears uppermost nut 20 to be forced gently against the lowermost end of the screw 14 so that it can be 50 engaged thereby when the motor is started in the proper direction. As in the first described embodiment, the sections may be held against relative rotation, for example by flutes in the major lengths of sections 12, II and 10 and en₅₅ gaging flutes in the enlarged portions of the sections 13, 12 and II, respectively, below the shoulders 48.

Our improved antenna may be mounted outside a vehicle, preferably on the roof thereof. 60 Thus, in Fig. 6, we have shown our antenna mounted on the sloping wall of a tank. The lower section of the antenna is connected by a spring assembly 51, which may preferably be of the same construction as that provided by the 65 springs 37 and 38, upon an insulator 52 carried by a bracket 53 mounted on the wall 54 of the tank. In this embodiment the shaft 21 terminates immediately below the lower end of the lower section and is connected to a motor 55 by 70 means of a flexible shaft 56 which extends upwardly through an opening in the insulator 52 and through the spring connection 51. An insulating connection 57 connects the shaft 56 to the motor and the lead-in 58 of the antenna may 75 be connected to the outer stationary portion of

2,301,202 the flexible shaft 66. It win readily be understood that the actuation of the motor 6B in either direction win effect a projection of the antenna or the retraction thereof. The spring connection Si enables the antenna to be moved past an 5 overhanging obstruction without injury to the antenna.

Our improved antenna may be mounted in other suitable locations on an automotive vehicle. Thus, as shown in Fig. 9, we may mount the an- 10 tenna on the roof of an automobile, preferably immediately above and behind the center of the windshield. For this purpose, we may employ a housing 6B whch may suitably be of plastc material upon the roof of an automobile. The hous- 15 Ing 60 may contain a motor 61 which is connected by an insulatng connector 62 to a shaft 63 which projects out of the housing at the angle which the antenna is intended to occupy.

The lowermost section 10 of the antenna is 20 rigidly secured to the close wound spring 64 which is rigidly mounted on the housing 60. Within the spring 64 is located a coaxial spring 65 under substantial tension and secured to the lower end of the section 10 and to the housing 60. A flexible 25 shaft 66 extends through the springs 64 and 65 and connects the shaft 63 to the shaft 21 which extends out of the lower end of the section 10 in the manner previously described. A lead-in wire 61 may be connected to the lower end of the sec- ³⁰tion 10 and it may pass through a suitable opening in the roof 68 of the automobile.

The motor 61 and the motors of the previously described embodiments may be connected to the battery of an automotive vehicle or to other ³⁵source of electrical energy by means of a conductor 65. The conductor 69 is connected to a single-pole three-position switch 70 whereby the line 69 may be connected to a line 11 or 72 connected to the motor 61 so as to drive the motor ⁴⁰61 in one direction or the other direction. In the normal intermediate position of the switch 10, no energy is supplied to the motor. The motor may have a single return wire 13 which may suitably be grounded. The switch 70 may be located ⁴⁵on the Instrument panel of an automobile or in other suitable position within the vehicle on which the antenna is mounted.

While particular embodiments of the present indention have been shown and described, it will ⁶be obvious to those skilled in the art that changes and modifications may be made without departing from this Invention in its broader aspects, and, therefore, the aim in the appended claims is to cover all such changes and modifications as ⁵⁵fall within the true spirit and scope of this invention.