US3187333A

US3187333A - Antenna scan torque reducer

Info

Publication number: US3187333A
Application number: US205623A
Authority: US
Inventors: Marek W Ciotek; Muller Kurt
Original assignee: ITE Circuit Breaker Co
Current assignee: ITE Circuit Breaker Co
Priority date: 1962-06-27
Filing date: 1962-06-27
Publication date: 1965-06-01
Anticipated expiration: 1982-06-01

Description

June` 1, 1965 Mammals @WAL 3,187,333

C$EN RQRQLE HEBlJCER {Filed June 27, 1962 5 Sheets-Sheet 1 FIG. l

June 1, 1955 M. w. cxoTEK ETAL 3,187,333

ANTENNA SCAN TORQUE REDUCER Filed June 27, 1962 5 Sheets-Sheet 2 'Q foray: Ff: /b

/o fz /4 la o", 30

June l, 1965 Filed June 27, 1962 M. W. CIOTEK ETAL ANTENNA SCAN TORQUE REDUCER INMENTORS fune L 1965 M. w. clorEKf; ETAL ANTENNA SCAN TORQUEI'TREDUCERX Fled' Jfune 27, 1962 www k ,Sl

June 1, 1965 M. w. cloTr-:K ETAL ANTENNA SCAN TORQUE REDUCER 5 Sheets-Sheet 5 Filed June 27, 1962 5 a, 9 //b///////////////// w v y r l u a u l w ,Q? 9 v., 9 9 ,a w

. ning motion.

Aexerted at the, instant of motion reversal.

j, Patented June 1, 1965 3,187,333 u 4 ANTENNA SCAN TORQUE REDUCER s Marek W. Ciotek and Kurt Muller, Philadelphia, Pa.,

assignors to I-T-E Circuit Breaker Company, Philadelphia, Pa., a corporation of Pennsylvania Filed .lune 27, 1962, Ser. No. 205,623

2 Claims. (Cl. 343-766) This invention relates'to a torque reducer, and more particularly to the use of an energy storage means in conjunction with an oscillating antenna scan drive to reduce the drive torque requirements.

It is known in many electronic communications and radar antenna systems to provide for an oscillatory scan- Such antenna systems typically include a drive means which'provides azimuth and/ or elevation motion for moving the'antenna from a lirst end position to a ,second end position, and then reversing the direction o-f movement to return to said first end position. This motion is then repeated, thereby providingan oscillation between the two end points. The basic drive means for effecting such an oscillatory motion usually include electric motors interconnected to the antenna shaft through a system of gears and an appropriate linkageV to convert the rotary motion to oscillating moti-on. Since antenna systemsusually have an appreciable amount of inertia, the torque requirements at the end of the stroke, whereat a reversal of motion takesplace, are quite considerable. The entire gear drivel of lsuch systems must therefore be designed to withstand the peak torque In addition,

the motion reversal at the `end of the path is accompanied With a torque reversal Vwith a change from deceleration to acceleration. Such a change causes backlash in the gearing, resulting in dyna-mic impact loading. K

Our invention avoids these high torque requirements of the pri-or art by providing an energy storage means to assist the motion and torque reversal at the end points of the scan.A Preferably, ,they energy storage means also coact with 4the drive means throughout a significant portion of the 'intermediatetraveh to thereby reduce the drive torque requirement over that portion too of the oscillating scan.

In one exemplary embodiment of our invention, the energy storing mean-s consists of compression springs which operatively engage an abutment member tostore the system kinetic energy during the decelerated travel towards the end point, and transfervthe stored energy to the drive means upon reversal of motion and accompanyf ing accelerated motion. If the springs are matched to perform exactly the same oscillation that thegear train produces,`the drive means will ideally be used to provide frictional and wind load torque only; the conversion of the kinetic energy during deceleration, to potential energy in the energy storing means,`providing the basic acceleration torque upon motion reversal.

The energy storage means are illus-trativelyV shown contained in housings connected to the antenna shaft at regions corresponding to the end points of azimuth travel. As the shaft oscillates between its end positions, the kinetic energy is alternatively stored in one of the energy storage means and subsequently transferredrto the antenna shaft upon motionre-versal and accompanying change of deceleration to acceleration. The springs and abutment member are preferably positioned to coact and provide energy transfer during a substantialportion of the overall oscillating motion.

As a furthcr`aspect, the abutment lmember which operates in conjunction with the energy storing means is re-tractablefr'om the path of theenergy storagemeans;

' ning.

Thus, in those system applications wherein both oscillating scanning and continues scanning are required, the

abutment member may be retracted to permit continuous scanning. The abutment member may at other times be positioned in the path of the energy storage means when oscillatory scanning is required. Where such a retractable'` abutment member is used, the switching means which converts the antenna scanning from an oscillatory mode to a continuous mode is preferably,interconnected to the abutment member retraction means to Vprevent theV antennafrom attempting to go intoa continuous mode of operation with the abutment means positioned in the energy u storage means path.

A preferred form which our invention may take uses a lSingle torsion storage means operatively interconnected to the antenna drive sha-ft. Our particular illust-rative construction uses a` torsion spring, one end of which is interconnected to the antenna shaft drive gear. When the other end of the torsion spring isV held stationary, the deceleration energy of the system will be transferred to the torsion spring wherein it is stored and transferredV back to the system during an acceleration period. This embodiment advantageously c-oaots with the drive means over the entire path of oscillatory scan thereby minimizing the` drive means torque requirements. As an additional advantage this embodiment may be contained within a lunitary housing adapted to be iieldsite installed to an existing antenna system as optional equipment. As a further feature of this embodiment, one end of the torsion spring is operatively connected to a braked member to permit both'oscillatory and kcontinuous scan. When continuous scan is required the brake is released. The torque reducerwill then be in idler gear engagement with the antenna drive gear.

It is thus seen that the basic concept of our invention resides in the use of energy storage means in conjunction with anV oscillatory scan antenna system, to convert the kineticenergy during .the deceleration period to potential energy for` utilization during the acceleration period, thereby veffecting a substantial reduction in the torque requirements of the antenna drive mechanism.

It is accordingly a primary object of this invention to utilize energy storing means in an antenna system n having an oscillating scan motion to thereby reduce `the drive means torque requirements. I K

A further object of this invention is to utilize a spring as a storage means Vt-o absorb the kinetic energy during the deceleration period of an antenna scan system and transfer said stored energyV to the antenna drive means during the acceleration period of the antenna scan.

An additional object of this invention is to provide in an antenna scan system, including an energy` storing means which operatively engages the antenna drive means at the end regions of its travel to provide a torque to assist in the reversal of antenna direction, thereby reducing the torque requirements of the basic antenna drive rmeans during motion reversal.

Another object of the invention is to provide such an energy storage means which also coacts with the antenna drive during the intermediate portions of travel, to thereby reduce the drive torque requirement over substantially the entire scan sector.

Still a further object of this invention is to utilize an energy storage mans in conjunction with an oscillating motion antenna scan system to provide a reduction of driveV troque requirements, said energy storage meansV being disengagable from the drive means to permit switching of the antenna system to a continuous modeof. scan- Still an additional object of the invention is to elect a torque reduction in thev'drive means required for oscillating sectorial motion of antenna systems by operatively connecting a torsion "energy storage means to the an- 3 deceleration period of travel, and transfer said' stored energy to the antenna drive during the acceleration period of the antenna scan.

Still another object of this invention is to provide for both a continuous and oscillating mode of antenna scanning in such an antenna system by releasing the other end of the torsion storage means during continuous mode scanning, thereby having the interconnecting gear serve as an idler gear.

Yet a further object of this invention is to effect a torque reduction in the drive means yrequired for oscillating sectorial motion of an antenna system, by operatively connecting a first and second energy storage mea-ns to the antenna shaft at positions associated with the end points of antenna scan, and moving said energy storage means as a unit with the antenna shaft in a path obstructed by an abutment member.

Yet an additional object of this invention is to provide for both a continuous and oscillating mode of antenna scanning in such an antenna system by providing for retraction of the abutment member from the path of the energy storage means during continuous mode scanning.

These as well as other objects of our invention will readily became apparent after'` reading the following description of the accompanying drawings in which:

FIGURE l is a simplified illustration of the movement of a pendulum to analogize the oscillating motion of a sectorial scan antenna.

FIGURE 2 is a simplied illustration depicting the basic concept of our invention.

FIGURE 3 is a simplified illustration of one embodiment of our invention.

FIGURE 4 is a typical drive means which may be used to provide both oscillating sectorial scan and continuous scan.

FIGURE 5 is a plan view of one embodiment of our invention, in accordance with the teachings of FIGURE 3.

FIGURE 6 is an end view along lines 6 6 of FIG- URE 5 and looking in the direction of the arrows, which illustrates the connection of the energy storing means to the antenna shaft.

FIGURE 7 is a cross-section along lines 7-7 of FIG- URE 5 and looking in the direction of the arrows, illustrating the retractable abutment `means of our invention.

FIGURE 8 is a simplified illustration of a preferred embodiment of an invention.

FIGURE 9 is a cross-sectional elevation of a torque reducer constructed in accordance with the teachings of FIGURE 8.

FIGURE 10 graphically illustrates the interrelation of the spring constant to the system torque requirements, showing `the resultant torque reduction obtained with our invention.

Referring initially to FIGURE 1 the oscillating motion of a sectorial scan antenna system may be analogized to the motion of pendulum 10, oscillating in a horizontal plane with simple harmonic motion between end points 11 and 12. At the center 13 of its stroke, pendulum 1G will have maximum velocity and hence maximum kinetic energy. As the pendulum travels to one end of its stroke, as for example 11, it will be decelerating, and therefore driving the gear train of the analogized antenna drive. Upon reaching end point 11 pendulum 19 will undergo a reversal in motion as it will now begin to travel back towards center position 13, and onto other end position 12. While traveling from positions 11 to 13, pendulum 10 undergoes a reve-rsa1 in torque direction, thereby being accelerated and demanding torque from the drive means motor of the analogized antenna drive. It is thus seen that the reversal of direction at end 11 (and 12) will impose a high torque requirement on the drive means of the analogized antenna system. The basic concept of our invention, the actual structure of which will be more fully set forth below, is to store the kinetic energy during the deceleration period of motion,as potential energy, and then utilize it during the acceleration period to assist in torque reversal and acceleration. In this manner the gears and motor of the drive means will ideally be used merely to provide and, transmit the frictional torque.

Reference is now made to FIGURE 2, which illustrates, in simplified form the basic concept of our invention. Antenna 14 is driven in an oscillatory manner between 15' and 15 by a motor drive 215, shown in simplified form. Rod 16 is connected to the antenna shaft at 17. Crank mechanism linkage bar 18 is pivoted at', one end 19 to rod 16 and at its other end 2t) to gear 21 of drive assembly 25. Motor 24 is interconnected by gears Z2 and 23 to gear 21 to provide an oscillating motion of antenna 15 via previously described linkage members 16 and 1S.

In accordance with the teachings of our invention energy storage means 30 are included. Energy storage means 30 are illustratively shown as a pair of compression springs 31, 32 appropriately matched to the dynamics of the system. Ends 33, 34 of

springs

31, 32 respectively are xedly connected to an appropriate pedestal member. Their opposite ends 35, 36 respectively abut linkage rod 16. Energy storing means 30 may alternatively include torsion bars or any other elastic elements properly matched to the dynamics of the oscillating motion of theparticular yantenna system. Also, springs 31 and 32 may conversely be secured at their ends 35, 36 to linkage rod 16 and strike abutting members placed at 33, 34. As antenna 14 is driven to one of the extremes of its oscillating motion, as for example 15 shown dotted for purposes of clarity, spring 32 will be compressed between rod 16 and the pedestal member to which end 34 is connected. This compression of spring member 32 effects the storage of the kinetic energy during the travel of the antenna from its intermediate position to end position 15, which kinetic energy is stored as potential energy in spring 32. Upon reaching position 15 the antenna drive will effect a reversal of direction of antenna 14, wherein it will move back towards intermediate position 15. During this interval, spring 32 will gradually expand, thereby transferring its kinetic energy to linkage rod 16 and the drive means associated therewith, to provide an accelerating force. Upon reaching intermediate position 15, spring 32 will be unloaded, and as the antenna moves towards its other end position 15 the aforo-described energy storage and transfer operation will take place in conjunction with spring 31.

It is thus seen that the storage of kinetic energy in 30 during deceleration of the antenna and its subsequent transfer during acceleration will effect a substantial reduction in the torque requirements of antenna drive assembly 25. Ideally, drive means 25 need provide frictional and Wind load torque only after initial start up.

It is naturally understood that various arrangements of positioning the energy storage means and abutment members may be practiced in accordance with the teachings of our invention to provide the requisite storage and transfer of energy between a storage means and the antenna drive means. One such system is shown in the simplified schematic of FIGURE 3, wherein spring actuated energy storage means 41, 42 are shown connected to the antenna shaft 43 of antenna system 40. Antenna shaft is illustratively shown as providing azimuth scanning for an antenna 45 interconnected thereto at upper region 44. Alternatively our invention may be practiced in conjunction with the elevation scanning mechanism of an antenna. Energy storage means 41, 42 are connected to shaft 43 at positions corresponding to the end positions of the antenna 45 azimuth sectorial scan. Drive means 50 having an output gear 51 is operatively connected to antenna shaft 43 Via gear 60 to provide the required oscillatory scan. 'The operation of drive means 50 will be subsequently set forth in conjunction with FIGURE 4.

Abutmentmem'beri70` is provided in the path of energy Vstoring means 41, 42. It Awill now be appreciated that as shaft 43 moves clockwise, spring member 42 willstrike abutment member 70, thereby having the kinetic energy of the system stored therein. Upon reaching its 43, and thereby effecting a reduction in the torque requirements of drive 50. As such counter-clockwise motion of shaft 43 is continued past itsintermediate position, energy storing spring 41 will then strike abutment Y member 70, thereby'etfecting an analogous storage and transferring of energy, as described above in conjunction with energy storage means 41.

Antenna system 40 is preferably designed to permit both an oscillating scanning and continuous scanning mode. To deactivate the torque reductionenergy storage means of our invention-during the continuous `scanning mode, abutment member 70 is retracted from the path of energy storing means 41, 42. This may typically berprovided by solenoid 71 havingabutment means 70 operatively connected to its armature. During the oscillating scan period of 4antenna -system 40, energy storing means 41, 42 preferably strike abutment means 70 at rightangles to the solenoid retraction motion. Switch means 72 is preferably interconnected to both solenoid 71 and drive means 50 as a safety device to prevent the drive motor frombeing energized should the antenna system be converted to continuous scanning and abutment member 70 fail to be retracted. For example, switch 72 may include a member in the physical path of the armature of solenoid 71 in its retracted position.

FIGURE 4 illustrates a typical drive means 50 which may be used in conjunction with antenna system'40 to provide both oscillating sectorialV scan and continuous scan. Gear 60 of shaft 43 (asalso shown in FIGURE 3) is directly driven by gear 51 of the drivemeans. Gear 51 may be alternatively driven in an oscillating manner via sector gear 52, or in'a continuous mode by gear 53, in accordance with particular braking signals set forth below.f To obtain oscillating sectorial movement, brake 65 is applied, thereby preventing movement of gear 54. Drive motor 76 will thereby translate to gear 61 via gears 55,` 56, 57, 58, and 62. Gear 61 is appropriately interconnected to gear 63 via crank and sector' gear 52. VGear 63 will thereby be driven in an oscillatory manner, which motion is directly transferred to gear 51 via drive shaft 64, thereby providing oscillatory sector scan of antenna shaft 43.

To switch to continuous mode scanning brake 65 is released and brake 75 applied. Brake 75 acts via gear 61 to maintain gear 62 stationary. ,In this condition inotor 76 will drive gear 53 in rotary motion via

gears

55, 56, 57, 58,59, 66, 67,754 and 60. Gear 53 will drive gear 63 in'rotary manner via gears 77, 69, 73 and 74. Gear 63 will in turn drive gear 51 via shaft 64, gear 51 driving gear 60 of antenna shaft 43. It is thus seen that by the alternate engagement of brakes 65 andr75 drive means 50 may provide oscillating antenna scan motion and continuous scan of shaft 43.

Reference is now made toFIGURES 5-7, which illustrate an antenna system torque reducer constructed in accordance with the aforementioned embodiment of our invention. The antenna shaft (such as 43 of FIGURE 3) includes a circular mounting plate 100. Energy storing means 101, 102 are secured to arcuately separated positions 103, 104 respectively of antenna shaft mounting plate 100. The antenna shaft which is driven by an appropriate drive means (such as 50 of FIGURE 3) carries plate 100 and energy storage means 101, 102, through Y a corresponding sector of the azimuth antenna scan.

Energy storing means 101, 102 are shown as including a spring 105, as 'the basic energy storing device thereof. Springs 105 are matched to the dynamics of the oscillating motion of the particular antenna' system, as will be shown in conjunction with the discussion` of FIG- UREV 10. In many instances' such motion will not kbe simple harmonic and therefore the acceleration and de-v celeration will not be linear with angular displacement. In those situations itis necessary for optimum performance to provide a non-linear spring characteristic, possibly having different stiffness for each side of the stroke. Where the antenna motion closely approximates simple harmonic motion, linear springs may be used. Abutment member 106 is suitably attached to the antenna pedestal and is interposed in the path of energy storing means 101,102. This may best be seen by comparing the fully unloaded energystorage means 101V with the retracted position shown by energy storage means 102. It is naturally understood that this is merely for illustrative purposes; energy storage means 102 being actually retracted only when in abutting engagement with 106. As shaft mounting plate is driven in the oscillating manner discussed above in conjunction with FIGURE 3, energy storing means 101, 102, which correspond to 41, 42 respectively of thattigure, Will react with abutment member 106, corresponding to member 70 of FIGURE 3, to effect the storage land transfer of energy, in the manner discussed above in conjunction with FIGURES.

Energy storing means 101, 102 aretypically shown connected in the manner shown in FIGURE 6 to the bottom portion of antenna shaft mounting plate 100. The construction of the energy storage means is best seen byv referring to energy storing means 102. Spring 105 is contained in a housing 106. Extension rod 107 abutting spring 105 at one end extends beyond the end 108 of housing 106 a sufficient length to engage abutment member 106 to effect the requisite translation of motion to spring 105 for energy storage and transfer, during a substantial portion of the scan path.' The lower tip 109 of rod 107 is preferably spherical to mate with circular abutment member 106. Plate 110 covers end 108. of energy storing housing 106', and is appropriately enclosed' by seal 111 and bushing 112. The rear end 113 of 'housing 106 is similarly sealed by plate 114 and bushing`115. Housing 106 is appropriately attached, as by welding, to connecting members 117 and 118, which in turn lare securably attached, as by bolted'rod-like members 119, 119', to antenna shaft mounting plate 100.` Rod-like members 119, 119', which project downward from the lower surface of antenna shaft mounting plate 100, appropriately positioned energy storage means 101, 102,

such that tip 109 engages abutment member 106. Memi ber` 106, 107 and 110 are preferably formed of standard available roll stock steel, and member 110, 114 and 118 of standard plate stock, for minimum manufacturing costs.

Reference is now made to FIGURE 7, which illustrates a typical construction of a retractable abutment member106, to provide an oscillating and continuous mode of antenna scanning, as set forth above in conjunction with FIGURE 3. Abutment member 106 is operatively connected to the armature of solenoid 120, said solenoid being activated upon switching to a continuous antenna scanning mode. Solenoid120 is preferably a spring loaded push type solenoid in which the piston reacts automatically by means of springs in the event of power failure. Abutment member 106 is removably connected to the armature 121 of solenoid 120 by roll pin V123 inserted in mating openings of

members

121 and 106. Abutment member 106 is contained in housing 124 appropriately enclosed as by end plate 125, seal 126 and bushing 127. Extension 128 of housing 124 is ap-V FIGURE 8 is a simplified illustration of a preferred i embodiment of our invention. By comparing to FIG- URE 3, it is seen that individual energy storage means 41, 42, abutment member 70 and associated switch 72 have been replaced by an integrated assembly 80 directly interconnected to antenna shaft drive gear 69. Assembly 80 includes gear member 81 which engages antenna drive gear 60. Lower shaft 82 extending from drive gear 81 is connected to end 83 of torsion member 85, which may typically be a torsion spring or torsion bar appropriately matched to the dynamics of the system. Opposite end 84 of torsion member 85 is connected to upper shaft 86, which is in turn connected to member 87', which in turn is braked by member 88. With brake member 88 engaged, member 87 will be stationary, and rotary motion of gear 81 will be directly translated to torsion member 85. It is thus apparent that with

members

87 and 88 braked, the oscillating scan motion of 60 will load torsion member 85 during the deceleration period of antenna scan, with said load being transferred back to the drive system during a period of shaft acceleration in the same manner as separate energy storage means 41, 42 of FIG- URE 3.

. Assembly 80 is preferably contained within a unitary assembly, which is designed to be readily adaptable to an existing antenna system 4t), as an optional item of equipment. Thus, this system has found particular applicability in the retrot and improvement of existing eld site antenna systems. Advantageously, this embodiment coacts with the drive means during the complete path of oscillating movement, thereby serving to reduce the torque at all portions of the travel.

During rotating scan, brake 88 is released thereby allowing free rotation of spring end 84. Hence gear 81 will act as an idler gear in conjunction with antenna drive gear 60.

FIGURE 9 is a cross-sectional elevation of a torque reducer constructed in accordance with the schematically illustrated system 80 of FIGURE 8, with like components being similarly numbered. Lower shaft 82 is connected to gear 81 via taper pin 89.

Shafts

82 and 86 are appropriately housed within supports 91 containing bearings 92 and bushing 93. Retaining rings 94 enclose the bearing assembly. The intermediate portion of torque reducer 80 is contained within support housing 90. O-rings 95 are appropriately placed to connect brake cover 96 to lower external housing 97, providing a unitary assembly for shipment and installation at the eld site.

Reference is now` made to FIGURE which graphically illustrates the manner in which the spring constant of the torque reducer coacts with the drive means to effect a reduction in drive torque requirements. Abscissa 130 indicates the angular position of the antenna shaft with respect to the center of its scan. Ordinate 131 indicates the requisite acceleration torque. Curve 132 represents typical torque requirements of an antenna system having a sectorial scan, before the addition of the torque reducer of our invention.

Dotted lines

133 and 134 indicate typical negative torques which may be obtained from the energy storage means of our invention. The resultant torque required from the antenna drive is the difference between curves 132 and the particular spring torque curves such as 133. Systems have been constructed in accordance with the teachings of our invention to provide a 3 to 1 torque reduction with an increase 'of less than 3% of the antenna system cost. By proper matching of the springs, any desired amplitude and frequency of oscillation can be achieved. By selecting springs matched to perform exactly the same c oscillation that the gear train is designed to produce, drive means 50 would ideally be required to merely supply suticient torque to overcome friction and wind load if any. The spring characteristics illustratively illustrated in 133 and 134 provide a linear torque displacement relation with respect to the pedestal. The antenna motion, however, due to nite dimensions of its crank linkage, deviates from simple harmonic motion, and hence its torque is not a linear function of displacement, as shown in curve 132.

It is thus seen that our invention provides an appreciable reduction in the torque requirements of an oscillating scan antenna drive, and is adapted to permit switch-over to continuous antenna scan. Ey effecting such a reduction in drive torque requirements, we provide an appreciable reduction in gear wear, brake unreliability, lubrication problems, shaft fatigue and similar failures which otherwise would reduce the usable life of the antenna system.

It is naturally understood that the basic concept of our invention may be practiced in various other embodiments other than that illustrated; thus We prefer not to be bound by the disclosure herein but only by the appended claims.

The embodiment of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. In an oscillatory antenna scan system including an antenna carrying shaft and a drive means oscillating said shaft about its axis between arcuate first and second end positions; the improvement comprising an energy storage means operatively connected to said shaft in a region including said rst and second end positions; means restraining the movement of said energy storage means; said energy storage means and restraining means operatively engaged to store energy during a deceleration period of oscillating antenna scan, and transfer said stored energy to said shaft during an acceleration period of antenna scan, whereby the torque requirement of said drive means is reduced; said energy storage means comprising a tor sion means having a rst and second end; one of said ends being twisted with respect to the other of said ends, about a longitudinal axis, to effect energy storage; said first end being directly connected to a first gear; said rst gear being in mesh engagement with said antenna drive means; said restraining means comprising a brake limiting the movement of said second end about said longitudinal axis; the releasing of said brake providing substantially unrestrained movement of said torsion means about said longitudinal axis, whereby said rst gear is in idler relationship with said antenna drive.

2. The energy storage means of claim 1, wherein said torsion means, first gear and brake comprise an integrated assembly adapted to be installed to an existing antenna system drive.

References Cited by the Examiner UNITED STATES PATENTS 1,744,548 1/ 30 Hershey 343-763 2,408,825 10/46 Varian et al. 343-763 2,698,902 1/55 Farrow et al 343-760 2,945,229 7/60 Klauser 343-766 2,945,384 7/60 Briden 343-763 2,956,279 10/60 Bartholoma 343-766 3,026,517 3/62 Nameth et al. 343-758 3,125,888 3/64 Fox et al. 343-766 ELI LIEBERMAN, Prima/'y Examiner.

HERMAN K. SAALBACH, Examiner.

Claims

1. IN AN OSCILLATORY ANTENNA SCAN SYSTEM INCLUDING AN ANTENNA CARRYING SHAFT AND A DRIVE MEANS OSCILLATING SAID SHAFT ABOUT ITS AXIS BETWEEN ARCUATE FIRST AND SECOND END POSITIONS; THE IMPROVEMENT COMPRISING AN ENERGY STORAGE MEANS OPERATIVELY CONNECTED TO SAID SHAFT IN A REGION INCLUDING SAID FIRST AND SECOND END POSITIONS; MEANS RESTRAINING THE MOVEMENT OF SAID ENERGY STORAGE MEANS; SAID ENERGY STORAGE MEANS AND RESTRAINING MEANS OPERATIVELY ENGAGED TO STORE ENERGY DURING A DECELERATION PERIOD OF OSCILLATING ANTENNA SCAN, AND TRANSFER SAID STORED ENERGY TO SAID SHAFT DURING AN ACCELERATION PERIOD OF ANTENNA SCAN, WHEREBY THE TORQUE REQUIREMENT OF SAID DRIVE MEANS IS REDUCED; SAID ENERGY STORAGE MEANS COMPRISING A TORSION MEANS HAVING A FIRST AND SECOND END; ONE OF SAID ENDS BEING TWISTED WITH RESPECT TO THE OTHER OF SAID ENDS, ABOUT A LONGITUDINAL AXIS, TO EFFECT ENERGY STORAGE; SAID FIRST END BEING DIRECTLY CONNECTED TO A FIRST GEAR; SAID FIRST GEAR BEING IN MESH ENGAGEMENT WITH SAID ANTENNA DRIVE MEANS; SAID RESTRAINING MEANS COMPRISING A BRAKE LIMITING THE MOVEMENT OF SAID SECOND END ABOUT SAID LONGITUDINAL AXIS; THE RELEASING OF SAID BRAKE PROVIDING SUBSTANTIALLY UNRESTRAINED MOVEMENT OF SAID TORSION MEANS ABOUT SAID LONGITUDINAL AXIS, WHEREBY SAID FIRST GEAR IS IN IDLER RELATIONSHIP WITH SAID ANTENNA DRIVE.