US2518511A - Scanner - Google Patents

Description

Aug. l5, 1950 G. E. wHlTE ErAL SCANNER 5 Sheets-Sheet 1 Filed Sept. 14, 1944 www NNUU' ,III Imm" G/F'FORD E.

INVENTORSW 006145 Cl G 'f EY.

Aug. 15, 1950 G. E. WHITE ETAL SCANNER 5 Sheets-Sheet 2 Filed Sept. 14,. 1944 Aug. 15, 1950 s. E. WHITE ETAL SCANNER 5 Sheets-Sheet 3 Filed Sept. 14, 1944 HHH H ellHH IIII|||IIIIIIIIIIIIIIIIIIIIIIIIH ATLTORNEY.

Aug. l5, 1950 G. E. WHITE Erm.

SCANNER 5 Sheets-Sheet 4 Filed Sept. 14, 1944 INVENToRs D GIF/FORD E. W/l 7E @Quema c 66 l ATTORNEY.

Aug. 15, 1950 G. E. WHITE ErAL 2,518,511

scANNER Filed sept. 14, 1944 s sheets-sheet 5 4 BY l y' 1 M yi f ATroRNEY.

Patented Aug. 15, 1950 SCANNER Gifford E. White, Hempstead, and Douglas Clegg,

Great Neck, N. Y., assignors to The Sperry Corporation, a corporation of Delaware Application September 14, 1944, Serial No. 554,038

141Claims. (Cl. Z50-33.65)

This invention relates to a scanning device and more particularly to a scanning device for projecting and scanning radiant energy beams.

An object of the invention is to provide a scanning device of simplified construction having greater emciency than Vformer scanning devices o f the kind.

The invention co-ntemplates an arrangement for projecting a sharply directed beam from a suitable antenna or other projecting device which is rotated about a spin aXis for what is generally described as a tracking operation, a further nodding motion being imparted to the projecting device icr searching operations. The nodding motion causes a solid angle of radiant energy to be transmitted in a series of spiral paths usually of a substantially conical shape whereby with suitable auxiliary apparatus an object within the area of the cone may be located and thereafter tracked by the apparatus. described in the copending application Serial No. 438,388 of Leon A. Maybarduk, et al., led April 10, 1942, now Patent No. 2,410,831 granted November 12, 1946. The present invention is directed particularly to an improved mechanism for spinning and imparting a nod motion to an antenna arrangement.

Another object of the invention is to provide a scanning device in which the number of moving parts of the spinning mechanism has been considerably reduced as compared with former devices of the kind and which can be made of small size and light weight for use on aircraft.

Still another object is the provision of an improved nod mechanism which allows a much faster and more positive return from any position in spiral scan to tracking than did previous mechanisms of the kind.

A further object is the provision of a novel and simplied mechanism for aligning the antenna automatically with respect to the spin axis on changing from spiral scan to track.

A still further object is the provision of an automatic speed regulating arrangement by which the rotary speed of the antenna is retarded at the larger nod angles to provide closer scanning in the outer areas of the spiral path of the antenna.

Other objects will appear1 in the following description given with the aid or the accompanying drawings, of which Fig. 1 is a side view of the scanning mechanism and its support;

Fig. 2 is an elevational view of the scanning mechanism and support;

These operations are Fig. 3 is a plan view, partly in sections, the section being taken through 3 3 of Fig. 8;

Figs. 4 and 5 are views showing details of the nod mechanism;

Fig. 6 is a View of the overrunning clutch, partly in section, the section being through 6-6 of Fig. 4;

Fig. 7 is a view in section of the nod mechanism, the section being taken through 1-1 of Fig. 5;

Fig. 8 is a view of the gear assembly for rotating the antenna, and also of the clutch mechanism for selectively controlling spin and nod motions thereof, as well as other pick oir gears driven from the antenna drive assembly;

Fig. 9 is a sectional view taken through 9 9 of Fig. 8 showing details of the clutch mechanism for selectively controlling spin and nod movements, and also the gearing connecting the drive motor therewith;

Fig. 10 is a sectional view taken through lll-i il of Fig. 8 showing the gear arrangement by which reference current generators are driven from the spin mechanism;

Fig. 11 is a sectional view through il--H of Fig. 8 which shows the cam drive for a nod reference generator;

Fig. 12 shows a cam operated switch for controlling the speed of the driving motor; Y

Fig. 13 is a circuit diagram for the motor speed contro-l; and

Fig. 14 shows the nod cam.

Referring to Figs. 1 and 2, casing IQ enclcses and supports the rotary members of the scanning mechanism. rIhe casing is supported substantially in balance by trunnions El! and El between the arms 22 and 23 of yoke 24 mounted for rotary azimuth movement in suitable bearings on a base 25. The yoke may be turned in azimuth by any suitable means, a gear sector 26 secured to the yoke and driven by gear 2'! of a suitable servo motor being shown for the purpose in the drawings.

Casing i9, Fig. 3, is an irregularly shaped casting preferably of a light metal having a head portion 28 provided with a cover the head comprising an approximately nat circular cavity. A tubular section 3E] of the casing projects from the midsection of the head and encloses a rotary sleeve 3l driven by gearing disposed within the head near one end of the sleeve. An enlarged end portion 3B of the sleeve, arranged to turn in bearings 39 suitably sealed against dust and moisture, supports, beyond the end of tubular section 30, a yoke 32 provided with arms 33 and 34 having near their ends aligned bearings in which a support for an antenna 35 and a reflector therefor are free to nod, under control of mechanism to be described, while the yoke and sleeve 3| are rotating.

The driving gear lil for the sleeve 3| is secured thereto by key 4|, Fig. 3. The gear is turned by the following mechanism. A driving motor 42, Fig. 9, supported by casing i9 has a shaft carrying a gear 43, which is connected thereto by a friction clutch 44. Gear 43 drives gears 45, 46

and 41, the latter being fastened to shaft 48 to which is keyed the driving member 49 of a clutch 5U, the driven member being formed on the side of gear 5| which is free to turn on the shaft when the clutch members are disengaged. Gear 5| is in mesh with gear 40 on the sleeve and turns the sleeve only when the clutch is engaged. The clutch is controlled by solenoid 54 supported by the casing. rlhe solenoidY controls a throw-ofi arm 52attached to shaft 53 pivoted to the casing. With the arrangement shown, when the solenoid is energized, the throw-off arm slides the driving member 49 along shaft 48 disengaging it from the driven member. Suitable spring means, not shown, tends to hold the clutch in engagement.

Gear 41, as described, is driven constantly by motor 42 independently of the clutch. Gear 41 is in mesh with gear 56 secured to a cam sleeve 51 having a ring 58 formed on its inner surface which rides on a bushing 59 disposed on sleeve 3| spaced by a washer from a tubular extension Bil of gear 4|). Gear 56 and the integrally formed sleeve 51 are free to turn with respect to gear 49 and sleeve v3| which are keyed together, but are restrained from axial movement by the ring 58, the edgeof which engages a spacing washer which rests against a shoulder 64 on sleeve Si. A portion of cam sleeve 51 adjacent to inner ring 58 is formed with an enlarged bore and on the surface of sleeve 3| and extending into the bore is a flanged ring 6| provided with a longitudinal groove 62 formed on its inner surface which rides -on a spline 63 on the outer surface of sleeve 3|. The ilanged ring, dueto the spline arrangement turns with sleeve 3| but may'move axially thereon under control of a cam mechanism about to be described.

A cam groove t5, Figs. 3 and 5, is formed in the outer surface of cam sleeve 51. Attached to the ilange E6 of ring 6| by means of a clamping ring 61 and screws G8 is an annular member 'ha'ving an inwardly extending ridge or ring 1li which rides on the surface of cam sleeve 51. A cam roller 1|, Fig. 5, which rides in cam groove 55 is supported for rotation on a stud 12 secured by clamp i3 to annular member 69.

If gears 4c and 56 are driven at diierent relative speeds, then the cain sleeve yand the cam roller will be rotating at different speeds about a common axis, referred to herein as the spin axis, thereby causing anged ring 6| to reciprocate on spline 63. This axial movement of ring 6| is used to impart a nodding motion to the antenna by Vmeans of a reciprocating shaft, to be described further on. rlhe mechanism for 'selectively controlling the nodding motion will now be described.

In a preferred embodiment of the invention, driving gears 40 and 56 are coupled together for tracking operations by means of an overrunning clutch. The clutch comprises a `pawl 15, Figs. 4 to 6, pivoted on a stud 16 in a slot 11 'formed in a ring 18 on the side of gear 56. The pawl cooperates with a single tooth '|9 formed on sleeve 4 E attached to gear 49. A spring urges pawl l1 into engagement with tooth 19.

The overrunning clutch operates as follows: Assuming that the gear ratios are such that gear 49 is turned more rapidly than gear 56 and that clutch 56, Fig. 9 is engaged so that both gears 49 and 55 are driven by motor 42, then, as indicated by the arrows of Fig. 6, both the pawl of gear 56 and the cooperating single tooth ratchet are turning in the same direction, but the gear carrying the tooth is turning at the greater rate, and the tooth `passes under the pawl periodically, the overrunning clutch, under the circumstances being ineiective. As already described, due to the relative movement of gears 49 and 55, the cam mechanism will cause the flanged ring 5| to reciprocate to provide a nodding motion to the antenna.

When clutch 59 is disengaged, the nodding movement is eliminated as follows: Gear 5| no longer drives gear 4B to which clutch tooth 'i9 is attached, but gear 56 is still driven from the motor. Pawl 15 carried by gear 55 will engage tooth 15 and will cause sleeve 3| and the associated parts to turn therewith at the same rate, and since there is no relative motion of the cam groove and its roller, the nodding movement stops. Due to the single tooth arrangement oi the clutch, sleeve 3| is always engaged in the same angular position, and in this position, the relation of the roller and cam groove is such that the antenna is maintained in alignment with the common spin axis of the members driven by gear 56 or at some desired angle with respect to this axis. Under these conditions the scanner may be used for so-called tracking operations.

When the solenoid 54 is deenergized, clutch 50 engages, and the nodding motion resumes as already described.

The novel nod and spin mechanism of the present inventionV is much simpler than former mechanisms o the kind. All spinning and nod movements are transmitted to the antenna support by but two gears, 45 and 56. No gears, racks, or rotary shafts are employed in the spinning portion of the mechanism, which, consequently, is greatly simplified and readily balanced. The clutch mechanism for selectively controlling gear 46 and the nod movement is stationary with re.- spect to the spin mechanism and the operation of the clutch imposes no external load on the spinning mechanism. The antenna is automatically aligned with respect to the spin axis when the overrunning clutch is effective which simplifies the device by eliminating special means, such as detents and the like for holding the antenna in alignment with the spin axis when tracking takes place. The change from search to track and vice versa occurs immediately after the solenoid is operated one way or the other, the time required for the change from search to track being unaiiected by the extent of the spiral movement of the antenna.

Sleeve 3| turns in bearing 39 held in position against a shoulder formed on the enlarged portion 38 of the sleeve by nut 9|) which is threaded thereon. Between the nut and bearing is a soft washer 9|. A cap'92 secured to the tubular extension 39 by screws 93 retains the bearing and sleeve against endwise movement. A soft washer 94 is inserted in the cap andother soft washers 95 are held by the cap against the side of the bearings to keep out dust and moisture and prevent oil leakage.

The opposite end of sleeve 3| is threaded, and assembled thereon and held in place by nut 98 `is a soft washer 97, a flange 98 and a bushing 99 separating the flange from the extension 59 of gear 49. Assembled on bushing 99 are a pair of rings |99 and |0| supported by a reentrant portion |02 of cover 29 which forms a support bearing for sleeve 3 I.

A tube |03, extending through sleeve 3| is associated with joints |94 and |05 at opposite ends thereof are a part of the high frequency plumbing. The following applications describe high frequency plumbing systems and elements thereof which might be used with the present scanning mechanism: Serial No. 441,188, of Holschuh, et

al., filed April 30, 1942; Serial N0. 471,780 f G. E.

White, led Jan. 8, 1943, now Patent No. 2,419,239 granted April 22, 1947; Serial No. 481,640, of Mallett, et al., led April 2, 1943; Serial No. 447,- 524, led June 18,V 1942, now Patent No. 2,407,318 granted September 10, 1946; and Serial No. 462,- 434, filed Oct. 17, 1942, now Patent No. 2,429,640 granted October 28, 1947, both of Mieher, et al.

Yoke 32,V which supports the antenna, is a hollow casting secured between spaced arms llil and il fastened to the part 38 of sleeve 3|, Fig. 4. A member |2, Fig. 3, which supports antenna 35 and reflector 3B is supported in bearing |23 and ||4 held respectively by arms 33 and 34 of yoke 32.

As shown in Fig. 4, a rod ||5 is pivoted at H5 to member |i2, the pivot being eccentrically disposed with respect to bearings I3 so that endwise movement of the rod will cause a rocking of the antenna assembly in its bearings. adjustable in length, a nut ||7 on an extension HB threaded into the rod being provided for adjustment purposes. Extension H8 is pivoted by pivot H9 to a shaft |29, Fig. 5, guided for reciprocation by a bearing I2| formed in the end -a portion 38 of sleeve 3l. The end of rod |25 is coupled as shown in Figs. 4, 5 and 8 by cross piece |22 and screws |23 to the flange 66 of ring 5|. By means of the reciprocating shaft arrangement just described connecting the ring 6| and the antenna assembly, the axial movement of the ring imparts a nodding movement to the antenna assembly, and when the axial movement of the ring ceases, the antenna assembly is held in a iixed position corresponding to that of the ring by the rod arrangement, and this, as already described is where the antenna is aligned with or substantially aligned with the spin axis, such position being adapted to be used for tracking purposes.

rlhe joint |95 of the wave guide plumbing is connected to the antenna input member |39 through joint |3 I, member |32 and a bent tubular member |33. Rotary joint |04 at the opposite end of tube |03 is connected by a tubular conducting member l34, Fig. 2, through a rotary joint |35 associated with trunnion member 25 of the elevation axis to a tubular member |38 through a rotary joint |37 associated with the azimuth axis to a horizontal portion |33 of the plumbing to which at |39 suitable external circuits may be connected. The upwardly extending portion |45 of the base 25, Fig. 1 may be used to support control switches for the device, or a control panel.

In'Fig. 2, an elevation gear sector |45 is shown attached to casing |9. The sector is positioned by gear |46 of a suitable servomotor arrangement |47 mounted on arm 23 of yoke 24 for turning the scanner in elevation.

Rod H5 is l mum nod angle.

A rotary transformer for furnishing a nod reference current is shown in Fig. 1l supported in a seat formed in the wall of casing 28 with the shaft |B| of its rotary member extending into the interior of the casing. A The transformer may be rotated in its seat for phase adjustment purposes. A crank |52, mounted on shaft |6|, enters an opening in one end of a lever |53 mounted on shaft I5. At the opposite end of lever |63, a roller |64 is mounted that acts as a cam follower for a cam |95 secured to shaft |55. Spring |66 holds the follower against the cam. Cam |65 is shaped to rock lever |59 in accordance with the variation of the nod angle of the antenna, and the lever effects a corresponding movement of the rotary member of the transformer with a resulting change in the transformer ratio. The nod cam is driven from gear 45, so consequently the operation of the cam depends on clutch 5B which controls the operation of gear 40. The cam and its shaft |44 are driven from gear 40 by a train of gears which mesh in the following order, best shown in Fig. 8. Gear 49 meshes with gear |59 and drives gears |5i, |52, |53, |54 the latter being secured on shaft |55, Fig. l1.

The present :invention provides for increased range and accuracy by scanning the outer areas of the cone more closely for a given normal spin rate than was possible with former scanners. This may be accomplished by decreasing the motor speed at the greater nod angles. Various means may be used for the purpose and an effective arrangement is shown in Figs. l1 and 12 where a cam 79 mounted on shaft |55 operates a switch i7 i during a 'portion of its rotary cycle. In a preferred arrangement, the cam is designed to actuate the switch during the time the nod angle is greater than some predetermined angle, for example 45.

Cam |79 operates switch |7| by means of a roller |72 that rides on the cam. One type of circuit arrangement for controlling the motor speed is shown in Fig. 13 where the contacts of the cam switch |7| are closed for the purpose of decreasing the speed of a conventional shunt wound motor having an armature |73, a series field |74, and a shunt eld |75, operated from a source of direct current. Resistance |75 in the armature circuit is bridged by the tongue and back contact of a relay |77 controlled by a circuit including the contacts of switch |7| and the tongue and back contact of a relay |78 which is interconnected by circuits, not shown, with the clutch solenoid 55, relay |78 being energized during tracking operations thereby disabling the control of switch over the motor circuit. With the circuit shown, the switch contacts will be closed at a predetermined nod angle operating relay i7? and breaking the shunt circuit around resistance |78, thereby reducing the speed of the motor and thus providing closer scanning in the outer area of the cone scanned by the antenna in s spiral path.

The load on the motor increases as the nod angle increases due to the antenna assembly becoming increasingly offset from the spin axis and since the speed of a shunt wound motor having resistance in the armature circuit is sensitive to load, the speed of the motor will further vary with the changing load as the nod angle changes, the speed being slowest at the maxi- Alternatively, if; the motor speed is constant at all nod angles the cam may be shaped to provide closer scanning at the greater nod angles by shaping the part of the cam inthe areas indicated by reference `#characters 119 in Fig. 14, so as to more closelywspace the spirals in the outer area of the cone. For the optimum Yscanning pattern,A however, the variable speed motor arrangement is employed together with a cam formed to provide :decreased spacing r.between the spirals at the. greater nod angles.

Gear 40 is in mesh with a gear l8,-Fi'gs. 8 and 1-0, on shaft 18| that carries a second gear |82 which meshes with gear |83 on the shaft |811 of a generator |35 Whose shaft is in alignment with and drives that of a second lgenerator l86.,or rotary transformer, mounted thereon. Members 185 and H35 are supported by a seat formed in ycasing 28 in which they may -be rotated for phasing. Their driving gear ratio is such that they turn at lthe same rate as thev spin axis. vGenerator H85 may be of any desired type but preferably is a two-phase generator to supplyV a two-phase reference current. The `member 185 may be of the Teletorque type of rotary transformer, the output of which is fed into a demodulator during search 'for controlling the spiral pattern of a cathode -ray tube.

Since many changes could be made in the -above construction and many apparently widely diierent vembodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in 'a-limiting sense.

What is claimed is:

1. In a scanning device "comprising an an'- t'enna, a pair of coaXially disposed sleeves, means for rotating the sleeves at different rates, a support for the antenna coupled with one of the sleeves whereby the antenna rotates therewith,

a bearing'turning with one of the sleeves, `a shaft supported for reciprocation in the bearing, means controlled 'by the relative movement of the sleeves for imparting a reciprocatory movement to the shaft, means controlled by said movement of the shaft for imparting a nodding movement 'to the antenna' in its support, and means for coupling `the sleeves in predetermined angular `relationto maintain the antenna in a xed angu lar position with respect to the axis of the sleeves.

2. In .a scanning device comprising an antenna, a pair of coaxially disposed sleeves, means for rotating theV sleeves at di'erent rates, a support for the antenna coupled with one of the sleeves whereby the antenna rotates therewith, a bearing turning with one of the sleeves, -a shaft supported for reciprocation in the bearing, cam means turning with the other of the sleeves for imparting a reciprocatory movement to the shaft, means controlled by the shaft for imparting a nodding movement to the antenna in its support, and means for coupling the sleeves in predetermined angular relation to maintain the antenna in anxed angular position with respect to the axis of the sleeves.

3. A scanning device comprising -a rotary antenna, means to rotate and nod the antennacomprising a pair of members, means for rotating the members at different rates about a common axis, means controlled by the relative movement of the members Afor imparting a nodding move- .ment to the antenna forsearch scanning, means for disconnecting the driving means from the 'more rapidly rotating member to eliminate the nodmovement of the antenna. means comprising an. over-running Aclutch effect-ive after -a disconnecting operation of said meanstov couple the members in predetermined angular relation whereby the members turn together for track scanning.

4. A mechanism for projecting a beamofradiant energy comprising a pair of coaxially disposed sleeves, driving means for each sleeve eiective to drive the sleeves yat differentl rates, a lshaft supported for endwise movement by one of the sleeves, a cam groove formed in the other sleeve, a roller in the groove coupled to the shaft whereby relative movement of the sleeves causes reciprocation of the shaft, a yoke supported for frotation by the more rapidly turningsleeve, a scanningV device `pivoted between the` arms of the yoke, a Vcoupling between `the device `and the shaft whereby the endwise movement thereof imparts a nodding movement to the scanning device, an overrunning clutch having drivingv and driven members Yconnected. to the respective sleeves, a second Vclutch effective when operated to disconnect the driving means from the more rapidly turning sleeve whereupon the overrunning clutch becomes. effective to couple the sleeves, causing both to turn at the same irate and thereby interrupt the nodding motion of the scanning device.

5. In a scanning device wherein an antenna is spun about an aXls for track scanning and-nodded as well as spun about the axis for. search scanning, a pair of members rotatable abouti-said axis, `a sup-port for the antenna coupled to one of the members so that the antenna rotates .therewith, a gear attached to each member, a driving arrangement for said gears comprising a shaft, a fdriven gear secured to the shaft meshing with one of said gears, a second gear free to turnl on the shaft meshed with the other of said gears, a clutch for coupling the second gear to the shaft whereby both members are driven, the gear ratios being `such as to turn the members at diiierent rates, means controlled by the relative movement of the members for imparting a nodding moveu ment to the antenna, a second clutch disposed v,between the'members operable after theuncoupling ofthe second gear from its shaft 4by the rst mentioned clutch to couple the members so that they turn at the same rate in predetermined angular relation whereby the nodding movement is eliminated.

6. In a scanning device wherein an vantenna-is spun about an axis for track` scanningand nodded Aas well as spun about the `axis for search scanning, a pair of members rotatable about the axis, a support for the vantenna coupled with one of the members so that thelantenna rotates "therewith, a gear attached to each member, a driving 'arrangement for said gears comprising a shaft, a driven gear secured to the shaft meshing with one of .said gears, a second gear free to turn on the shaft meshed with the other ofsaid gears, a clutch for coupling the second gear to the shaft Athereby causing both members to be driven, the

7. A scanning device according to claim 3, in which reference current generator means `are driven from the driving means for the more rapidly turning sleeve, whereby after the operation of the disconnecting means the generator means are turned at the rate of the slower sleeve.

8. A scanning device according to claim 3, in which a two-phase reference current generator is driven from the driving means for the more rapidly turning sleeve, whereby after the operation of the disconnecting means the generator is turned at the rate of the other sleeve.

9. A scanning device according to claim 3, in which means for periodically changing the speed of said rotating means is turned by said rotating means.

10. A scanning device according to claim 3, in which said rotating means comprises a motor and gears driven thereby, a cam disposed to be turned by the gearing, and switch means -controlled by the cam for changing the speed of the motor in predetermined angular positions of the sleeves.

11. A scanning device according to claim 3, in

which said rotating means comprises a motor and gear means driven thereby, a cam disposed to be turned by the gear means, switch means con- Y prises a motor and gear means driven thereby, a

cam adapted to be rotated by the gear means, switch means controlled by the cam, and circuits controlled by the switch means for reducing the speed of the motor to provide closer scanning at the greater nod angles.

13. A scanning device according to claim 3, in which said means for rotating the members comprises a motor and gear means driven thereby, a cam adapted to be rotated by the gear means, means controlled by the cam for reducing the speed of the motor at the greater nod angles to provide closer scanning, and means controlled by the disconnecting means for rendering the speed reducing means ineffective.

14. A scanning device according to claim 3, in which said means for rotating the members comprises a motor and gear means driven thereby, means driven by the gear means for changing the motor speed periodically, and means controlied by the disconnecting means for rendering the speed changing means ineffective.

GIFFORD WHITE. DOUGLAS CLEGG.

REFERENCES CITED y The following references are of record in the ile of this patent:

UNITED STATES PATENTS Number Name Date 1,026,498 Delauna-Belleville May 14, 1912 2,407,305 Langstroth et al. Sept. 10, 1946 2,407,310 Lundy et al Sept. 10, 1946 2,410,831 Maybarduk et al. Nov. 12, 1946 2,412,867 Briggs et al Dec. 17, 1946

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