US2439411A

US2439411A - Portable two-way wave-signal space-communication set

Info

Publication number: US2439411A
Application number: US543167A
Authority: US
Inventors: Donald H Mitchell
Original assignee: Motorola Inc
Current assignee: Motorola Solutions Inc
Priority date: 1944-07-01
Filing date: 1944-07-01
Publication date: 1948-04-13
Anticipated expiration: 1965-04-13

Description

April 3, 1948. D. H. MITCHELL 439,411

PORTABLE TWO-WAY WAVE SIGNAL SPACE-COMMUNICATION SET Filed July 1, 1944 6 Sheets-Sheet l April 13, 1948. D. H. MITCHELL PORTABLE TWO-WAY WAVE SIGNAL SPACE-COMMUNICATION SET Filed July 1, 1944 6 Sheets-Sheet 2 frzz/enforx flan/QM H/Ytfcei April 13, 1948. D. H. MITCHELL PORTABLE TWO-WAY WAVE SIGNAL SPACE-COMMUNICATION SET Filed July 1, 1944 SSheets-Sheet 3 April 13, 1948.

D. H. MiTHELL 2,439,411

PORTABLE TWO-WAY WAVE SIGNAL SPACE-COMMUNICATION SET Filed July 1, 1944 V6 Sheets-Sheet 4 April 1948. DB. MITCHELL- 2,439,411

PORTABLE TWO-WAY WAVE SIGNAL. SPACE-COMMUNICATION SET Filed July 1, 1944 6 Sheets-Sheet 5 fnz/eni 7':- flanald/ H M Lit/2e16,

April 1948- D. H. MITCHELL 2,439,411

PORTABLE TWO-WAY WAVE SIGNAL SPACE-COMMUNICATION SET Filed July 1, 1944 6 Sheets-Sheet 6 31 Q .136 I/II/IIIIII'I/IIII/ I VIII/11111111111 1 a Patented Apr. 13, 1948 PORTABLE TWO-WAY WAVE-SIGNAL SPACE-COMNIUNICATION SET Donald H. Mitchell, Chicago, 111., assignor to Motorola, Inc., a corporation of Illinois Application July 1, 1944, Serial No. 543,167 Claims. (01. 25043) This invention relates to a portable two-way wave-signal space-communication set and more particularly to such a set of the type comprising a complete self-contained radio transmitter-receiver set includin a mouth-piece and an earpiece and dimensioned and shaped so that it may be readily grasped in the hand of the operator and used in the manner of a conventional telephone receiver,

In applicants copending application Serial No. 431,722, filed February 20, 1942, now U. S. Patent Number 2,439,408, entitled Portable radio device, and assigned to the same assignee as the present application, there is described and claimed a portable radio transmitter-receiver of the type referred to. The present invention constitutes an improvement on that of the said copending application.

It is an object of the invention to provide a new and improved portable two-way wave-signal space-communication set by means of which the replacement of components becoming defective in service is facilitated.

t is another object of the invention to provide a new and improved portable two-way wavesignal space-communication set in which the antenna and the chassis are removable from the housing independently of each other and of any other portion of the set.

It is a further object of the invention to provide a new and improved portable two-way Wavesignal space-communication set of increased simplicity of construction and operation and of improved performance.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following description taken in connection With the accompanying drawings while its scope will'be pointed out in the appended claims.

In accordance with the invention, a self-contained portable two-way wave-signal space-communication set comprises an elongated unitary chassis including transmitting and receiving circuit means, and signal-transmitting and signalreproducing devices. The set also-comprises an elongated housing closely fitting about the ch'assis and being longitudinally divided into base and cover portions proportioned, when open, to expose normally replaceable elements of the chassis for replacement. The set also includes provisions within the housing for receiving power supply means for the set, which may be one or more dry batteries, a vibrator power pack, or a selected one of either of these two conventional forms of power supply.

Further in accordance with the invention, a self-contained portable two-way wave-signal space-communication set comprises an elongated unitary chassis including transmittin and receiving circuit means, and. signal-transmitting and signal-reproducing devices. The set also comprises an elongated housing closely fitting about the chassis and comprising base and cover portions proportioned, when, open, to permit removal of the chassis. The set is also provided with an extensible antenna supported solely from and within the housing and mechanically independent of the chassis but electrically connectible thereto, whereby the chassis may be removed from the housing independently of the antenna or vice versa.

In the drawings,

Fig. la is a perspective view in elevation of the portable set of the invention with the cover opened;

Fig. 1b is a perspective view of a power supply unit for use in connection with the set of Fig. 1a, while Fig. 1c is a perspective view of batteries which may be used in lieu of the power supply unit of Fig. 1b;

Fig. 2a is a top perspective view of the chassis portion of the set of Fig. 1a, while Fig. 2b is a bottom perspective view of such chassis;

Fig, 3 is a circuit diagram, partially schematic, of the transmitting and receiving circuit of the set of Fig. 1a;

Fig. 4 is a view of the set of Fig. 1a. in use as a hand held set;

Fig. 5a is a view of the set of Figs. 1 and 1a, supported from the operator by strapping means and utilizing an auxiliary headset, while Fig. 5b is rear view of the same application of the set of the invention;

Fig. 6a is an elevation and Fig. 6b is a longitudinal section of the improved extensible antenna utilized in the set of Fig. 1a;

Fig. 6c is a view of the enclosing case for the antenna of Figs. 6a and 6b Fig. 7a is a front elevation and Fig. 7b a side elevation of a switch for controlling the energizatlon of the set, while Fig. 8 is a detail of a vent for the set housing.

Referring now to Figs. 1a., 2a and 2b of the drawings, there is represented a self-contained portable two-way wave-signal space-communication set embodying the inventlon and comprisin Fig. 1a, the portions 13a. and 13b of the housing are proportioned so that, when open, they expose the normally replaceable elements of the chassis it for replacement. The coverportion I319 may be secured to the base portion |3aby hinge-like hasps Hi and locked in place by hasps l5. Preferably, there is disposed a sealing gasket 01 washer lSc in the top of the cover portion liib near the periphery thereof for engaging a rim |3d of the base portion [3a fortightly closing or sealing the housing of the set.

There are included within the housing i311, itbprovisions for receiving the power supply means for the set. Preferably, these provisions are incorporated inthe chassis and may be in the form of a compartment consisting of a well um and a pair of end brackets Nib which together are proportioned selectively to receive either battery means, such as an A battery l6 and a B battery I! (Fig. 1c) or a self-contained power supply unit It (Fig. 117) preferably including a storage battery and a vibrator or other means for converting the. low-voltage direct current into a suitable operating voltage. In either event, the powersupply means of the type described are supported solely by the chassis compartment of the type describedrather than being supported from the

housing

13a, 13b. The compartment comprising the well Ilia and the end brackets ltb includes resilient means such as springs 69 and 23 for retaining the battery means in the compartment. As apparent from a consideration of Figs. land 1c, the A battery is adapted to be disposed in the well la and the B, battery 57 is adapted to be held by the end brackets tab of the compartment. Preferably, each of the springs I9 and 20 includes auxiliary locking means (not shown) for retaining them in a compressedcondition when the set is to be operated from the power supply unit it. The power supply unit H3 is of such configuration that it can be positioned .on the chassis in the compartmentwith a portion thereof extending in the well Mia and the remainder extending in the space between the end brackets 98b. The unit 43 is provided with a plug l8a,

cooperating with a socket N30 for making suitable electrical connections between the power supply means and the transmitter-receiver chassis l0.

The transmitter-receiver circuit incorporated in chassis it may be of any type suitable for the service intended. By way of example, there is illustrated in Fig. 3 a circuit diagram, partially schematic, of a complete wave-signal receiving circuit and a separate wave-signal transmitting circuit which is suitable for embodiment in the chassis iii. Since the circuit of Fig. 3 is substantially conventional, it is considered unnecessary to describe it in detail; however, the basic components will be identified and indicated by the reference numerals which are also applied to corresponding components of the chassis in Figs.

2a and. 2b. In brief,.the receiving circuit com-.

prises an antenna 20, a radio-frequency ampliher 2! coupled in cascade with an oscillator modulator 22, an intermediate-frequency transformer 213, an intermediate-frequency amplifier 2d, a second intermediate-frequency transformer 25, a detector and first audio-frequency amplifier 2%, a second audio-frequency amplifier 21 and an output transformer 28, having a secondary winding adapted to be connected to the loud speaker i2 through a press-to-talk selector switch 44.

The transmitting circuit of Fig. 3 comprises an inputtransformer 3! adapted to be connected to the internal microphone H through the selector switch lid. The contacts at and y of the selector switched also serve selectively to energize the filaments of the tubes of the receiving channel and the transmitting channel, respectively. The switch lid is provided with an operating push button sea (Fig. 2b) adapted to register with a flexible diaphragm sealing an aperture in the housing base l3a so that it may be pressed from the exterior of the housing by the operator to transfer the circuits of the set from operation as a receiver to operation as a transmitter.

. The output transformer 28 also has an additional secondary winding adapted to be connected to an external signal-reproducing device or earphone, while the input transformer 3! also has an additional primary winding adapted to be connected to an external signal-transmitting device or microphone. For this purpose, there are provided the jacks 29, 32 for individually receiving plugs associated with the remote signalreproducing and signaltransmitting devices, respectively, and there is provided a switch 45 (Figs. la and 3) mounted in thehousing cover iBh and accessible when the housing cover is open for individually connecting the signal-input circuit of the transmitting circuit and the signal-output circuit of the receiver circuit to the said signal-transmitting and signal-reproducing devices, respectively, or tothejacks 29 and 32, respectively. 7

The secondary winding of input transformer 31 is coupled to the duplex tube 32a comprising an oscillator and first audio-frequency amplifier however, if desired, the power supply unit 18 may be substituted therefor, the circuit diagram thereof being as illustrated and connectible to the power circuits of the receiver'and transm tter of Fig. 3 by means of the plug Eta and socket iilc.

The receiver set also preferably includes a unit assembly of the tuned circuits for the radio frequency amplifierZl, the power'amplifier 33 and the crystals for the oscillator 22 of the receiver and the oscillator'33 of the transmitter. This tuning unit is represented at Mend includes a socket Sta adapted to register with a plug Hid of the chassis. The tuning unit 34 as represented in Fig. la is provided with a recess including a shielding. cam which fitslover and encloses the radio-frequency, amplifier 2 i,

The set also includes an extensible antenna 35 supported within the base portion Hi of housing and preferably supported solely therefrom so as to be mechanically independent of the chassis but electrically connectible thereto. The details of the antenna 35 are illustrated in Figs. 6a and 62) from which it is seen that it comprises the well known telescopic construction comprising an outermost sleeve or cylinder 35a. and a plurality of

inner sleeves

35b, 35c, 35d and 358, terminating in a friction or gripping knob 35f. Each of the inner sleeves 35b to 35c, inclusive, is provided with a spring contact element 35g which is fastened to the inside of the sleeve near the end thereof, as by a spot-weld, and extends outwardly through an aperture to make a sliding spring contact with the next outer sleeve, thus insuring a good electrical continuity from the innermost sleeve 352 to the outer sleeve 35a. Between the successive sleeves and near the outer ends thereof there is provided an extended washer of packing material 35h to minimize the entrance of dust, moisture, etc., at the outer end of the antenna.

There are provided means external of the housing base 13a for removably supporting the antenna 35 from the housing and securing it thereto, this means constituting the sole support of the antenna, whereby the antenna. may be removed from the housing independently of the chassis or of any other portion of the set. This securing means comprises a ferrule 36 having a head 36a formed thereon for actuation by a wrench and having a threaded portion 36b for engaging an internally threaded mounting bracket 31 secured to the back of the housing base [3a (see Fig. 6c). The head 35a cooperates with a gasket 38 of rubber or other resilient material to form a sealing flange; that is, the ferrule and gasket 38 provide a sealing flange for sealing the antenna to the housing base [3a while permitting removal of the antenna. The ferrule is also provided with an inwardly projecting sleeve 360 on which is supported a resilient split contact sleeve 39 for establishing and maintainin electrical contact with the mounting bracket 33. Extending from the mounting bracket 3'! is a tubular sleeve 39 of insulation material, such as Bakelite, the other end of which is supported in a mounting bracket 40 disposed at the other end of the housing base 13a. The bracket 40 is provided with apertures 40a registering with holes in the jacks 29 and 32, Figs. 2a, 21), for connection to an external headset. Attached to the inner end of the sleeve'35a is an enlarged cap 352 which engages the sleeve 360 when the antenna is extended to prevent complete withdrawal of the antenna from the housing except upon the removal of the ferrule 36. Secured to the upper end of the ferrule 36 is a. cup-shaped packing member ll for packing the joint between the ferrule 35 and the outermost sleeve 35a against entry of dirt, moisture, etc. The supporting bracket 31 is provided with a machined electrical contact element 31a which, when the chassis I0 is inserted in the casing, registers with a contact 42 (Figs. 2b, 3) connected to the tuning unit plug Hid.

The set also includes switch means mounted on the chassis for controlling the energization thereof and including actuating means engageable by the antenna 35 when it is substantially inserted within the housing for operating the switch to circuit-opening position but normally being biased to circuit-closing position and operable thereto upon extension of the antenna from the housing. This switch may be in the form of a slide switch 30 (Fig. 21)) having a pivoted actuating lever 30a which, when the antenna is withdrawn from the casing, extends through a slot 39a (Fig. 6c) of the antenna tube 39. Upon insertion of the antenna for a sub- 6 stantial distance into the tube 39, and thus into the housing, the antenna cap 351 ejects the actuating lever 38a from the tube 39 to operate the switch.

The details of the slide switch 30 are shown in Figs. 1a and lb. The pivoted lever 30a is provided with an angularly projecting arm or lug 3%, the end of which is pivotally connected with a slide member 380 by means of a pin 30d. The slide member 300 is provided with a pair of pins See riveted or otherwise secured thereto and extending through slots 30 in a mounting plate 369, to the other side of which is riveted a sheet of fiber or other insulating material 30h. To the other end of the guide pins 30c is riveted or otherwise secured an electrical shorting plate 302' cooperating with the three spring clip contacts 307', the center one of which is connected to a terminal talc mounted on the grounded mounting plate 39g, while the other clips are connected to insulated terminals 36m and 3012, respectively. The ends of the mounting plate 30g are formed as upturned flanges 300 for suitably mounting the switch. The slide member 300 is biased by a spring .tiigo to the position shown in Figs. 2b and 7a with the lever 30a extending beyond the limits of the switch and into the aperture 39a (Fig. 60) for engagement by the antenna. upon insertion thereof.

In case the set is used with the power supply unit it, Fig. 11), including a wet storage battery and a vibrating power pack, the storage battery generates gas during operation and it is desirable to release this gas, at the same time sealing the housing lSa, I3b at all other points and at this point except when utilizing the power supply means it. To this end, the storage battery we (Fig. 8) of the power pack I8 is provided with a nipple-like gas vent [81), while the housing cover portion 13b is provided with an aperture [3e therein and a self-sealing vent 43 is so disposed therein as to register with the battery vent. The self-sealing vent 43 comprises a cylindrical plug 3a provided with an enlarged head #31) and with longitudinal flutings 43c and a cross fluting or channel 43d interconnecting the fiutings 430 at the face of the enlarged head 43b. Fitting over the plug 430. and its enlarged head is a flanged sleeve ite of rubber or like resilient material cooperating with a second flanged sleeve 43] closely surrounding the plug 43a and projecting through the aperture I36 in the housing cover 322. The flanges of the sleeves 43c and 431 are sealed together and to the housing l3b by a cupshaped member 43g which is riveted or otherwise suitably secured to the housing 13b. Surrounding the sleeve 43a is a spiral biasing spring 43h which, when the chassis and the power supply unit are in position, biases a shoulder on the sleeve 43c into engagement with the battery vent i312. The other end of the plug 43a is provided with an enlarged cap or head 431' secured thereto by suitable means such as a screw 42w. Thus it is seen that, when the cover portion I31) and the power supply I8 are in the relative positions shown in Fig. 8, there is a tight seal between the casing 31) and the battery vent 18b to permit escape of gas generated by the battery of the power supply means while at the same time the housing I3b is sealed with respect to all other portions of the set. When the set is operating from batteries and the power supply unit it is removed, the biasing spring 43h forces the rubber sleeve 43c inwardly and this sleeve, in turn, engages the head 43?) of the plug 43a,

point strap fitting 5.8.

forcing itinwa'rdly until its head 432' engages the sealing sleeve 43], whereupon the aperture we of the housing I3b-is completely sealed; that is, the self-sealing vent is disposed to be opened by the battery vent when the battery is in place but includes means for biasing-it to seal the housing vent or aperture except for connection to-the battery vent.

In Fig. 4 is a pictorial representation 'of'the use of the set as a hand held set. The elongated casing is shaped .so that it 'may be conveniently grasped by the operator while the sound reproducer or earpiece and the microphone or mouthpiece are relatively disposed as man ordinary telephone hand receiver, so that the operator can utilize the apparatus in a similarfashion. The

set is normally connected .to operate as a reset is ready to operate as a transmitter.

Figs. 5a and 5b illustrate .the'operation f the .set with an extension hand-set '50 provided with .a connecting cable andplugs52 for insertion .in the jacks 29, 32 of the chassis.

For this use, the set is provided with

strap fittings

53, 54 at each end of the housing base I3a.and a mid-- An extensible shoulder strap 55 is connected between theend fittings :53, 56, while an extensible chest strap 511s attached to the midpoint. fitting 5t andincludes provisions for detachably engaging one of the

strap fittings

53 or 54 and, when detached-therefrom, to pass around the operators body "and engage the shoulder strapv at a' point approximately opposite-the midpoint fitting 56, thus to support the set securely from the operators body without any manipulation. When'used with the extension headset, as illustrated in Figs. c, 5a and 5b, the operation .is'the sameas when used as a hand held set, except that in this instance the switch id is replaced'bya switch included in the grip of the headset. 50.

While the portable two-way wave-signal set of the invention is adaptable to a'wide range of service applications, there follows by way of example the primary electrical characteristics of a particular set which has been found to be satisfactory in opera ion.

Frequency of both transmitting and receiv- While there has been described what is at present considered to be the preferred embodiment of the invention, it will .be apparent to those" skilled in the art that various changes and modifications may be made therein .without departing rom the spirit or .scope ofltheinvention.

I claim: 1. A self-contained portable "two-way wavesignal space-communication set comprising, elongated unitary chassis including transmitting and receiving circuit means and a compartment for receiving power supply means for energizing said transmitting and receiving circuit means, signal-transmitting and signal-reproducing devices, an elongated housing enclosing said chassis and said devices and being longitudinally divided into base and cover portions, said chassis being positioned in said housing so that when said base and cover-portions thereof are open said power supply means and normally replaceable elements of said circuit means are exposed for replacement, said compartment bein proportioned to receive either non-renewable battery means or a self-contained power converter supply unit and including disengageable connectors for making electrical connections thereto.

2. A self-contained portable two-way wave-signal space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means and a compartment for receiving power supply means for energizing said transmitting and receiving circuit means, signaltransmitting and signal-reproducing devices, an

elongated housing enclosing said chassis and said devices and being longitudinally divided into base and cover portions, said chassis being positioned in said housing so that when said base and cover portions thereof are open said power supply means and normally replaceable elements of said circuit meansare exposedfor replacement, said compartment being proportioned to receive either battery means or a self-contained power converter supply unit and including disengageable connectors for supporting and making electrical connection to said battery means and additional disengageable connectors for supporting and making electrical connection to said self-containedpower converter supply unit.

3. A self-contained portable two-way wave-signal space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means, signal-transmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and com-.

prising base and cover portions proportioned when open to-permit removal of said chassis, and

an extensible antenna supported within said housing and including securing means external of said housing, said securing means being removable so-that said antenna can be removed from said housing independently of any other portion of the set.

4. A self-contained portable two-way wave-signal space communication set comprising, an elongated unitarychassis including transmitting :and receiving circuit means, signal-transmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said :chassis and also enclosing said devices and comprising base and cover portions proportioned when .open to ;.permit removal of said chassis, and an extensibleantenna supported within said housing .and including securing means external of said housing, said securing-means being removable so that said'antenna can be removed from said housing independently of any other portion of :nal space-communication set comprising, an

elongated unitary chassis including transmitting and receiving circuit means, signal-transmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and com prising base and cover portions proportioned when open to permit removal of said chassis, said housing having an opening in one end thereof, and an antenna assembly supported within said housing and including an extensible antenna and a ferrule for receiving said antenna and provided with a sealing flange and a threaded portion engaging and extending into said aperture in said housin said ferrule being removable from said housing so that said antenna assembly can be removed from said housing independently of any other portion of the set, said sealing flange serving to seal said aperture through which said antenna extends.

6. A self-contained portable two-way wave-signa-l space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means, signaLtransmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and comprising base and cover portions proportioned when open to permit removal of said chassis, and an extensible antenna including supporting means for supporting the same solely from and Within said housing and mechanically independent of said chassis, said antenna and its supporting means being out of the path of move ment of said chassis during its removal, and switch means mounted on said chassis for controlling the energization of said circuit means and operable to circuit-closing position upon extension of said antenna from said housing.

7. A self-contained portable two-way wave-signal space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means, signaLtransmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and comprising base and cover portions proportioned when open to permit removal of said chassis, and an extensible antenna including supporting means for supporting the same solely from and within said housing and mechanically independent of said chassis, said antenna and its supporting means being out of the path of movement of said chassis during its removal, and switch means mounted on said chassis for controlling the energization of said circuit means and biased to circuit-closing position and including actuating means engageable by said antenna when substantially inserted within said housing for operating the switch means to circuit-opening position.

8. A self-contained portable two-way wave-signal space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means, signal-transmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and being longitudinally divided into base and cover portions proportioned when open to expose normally replaceable elements of said chassis for replacement, and provisions for receiving within said housing a power supply means for the set including a storage battery having a gas vent, and a self-sealing vent disposed in said housing to register with said battery vent.

9. A self -contained portable two-way wave-signal space-communication set comprising, an elongated unitary chassis including transmitting and signal-reproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and being longitudinally divided into base and cover portions proportioned when open to expose normally replaceable elements of said chassis for replacement, and provisions for receiving within said housing a powe supply means for the set including a storage battery having a gas vent, a vent in said housing disposed to register with said battery vent, and a resilient seal for said housing vent disposed to be opened by the battery vent when in place and including means for biasing it to seal said housing vent except for connection to said battery vent.

19. A self-contained portable two-Way Wavesignal space-communication set comprising, an elongated unitary chassis including transmitting and receiving circuit means including a transmitter signal-input circuit and a receiver signal output circuit, signal-transmitting and signalreproducing devices, an elongated housing closely fitting about and enclosing said chassis and also enclosing said devices and being longitudinally divided into base and cover portions proportioned when open to expose normally replaceable elements of said chassis for replacement, jacks for individually receivin plugs associated with remote signal-transmitting and signal-reproducing devices, and switch means mounted within said housing and accessible when said cover is open for individually connecting the signal-input circuit of said transmitter circuit and the signaloutput circuit of the receiver circuit, respectively, to said set signal-transmitting and signal-reproducing devices or to said jacks, and provisions within said housing for receiving power supply means for the set.

DONALD H. MITCHELL.

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

UNITED STATES PATENTS Number Name Date 1,531,696 Grebe Mar. 31, 1925 1,765,027 Mitchell June 17, 1930 1,783,899 Barton Dec. 2, 1930 1,903,665 Adey Apr. 11, 1933 1,991,604 Drabin Feb. 19, 1935 2,142,993 Brown Jan. 10, 1939 2,252,671 Ludwig Aug. 12, 1941 2,276,933 Collom Mar. 17, 1942 2,285,083 Cover, Sr. June 2, 1942 2,337,987 Galloway Dec. 28, 1943 2,378,663 Striker June 19, 1945 FOR IGN PATENTS Number Country Date 462,529 Great Britain Mar. 4, 1937 OTHER REFERENCES Radio Craft, pages 464, 465, 505 and 507; Feb. 1939.