[1]K-atented Oct. 18, 1949 21485,278 UNITED STATES PATENT OFFICE 2,485,278 HAND MICROPI-IONE AND SWITCH Webster E. Gilman, River Forest, and Raymond C. Bierman, Clarendon HUls, Ill., assignors to Permoflux Corporation, Chicago, Ill., a corporation of Illinois Application March 31, 1945, Serial No. 585,910 -11 Claims. (Cl. 179-121) 2 This invention relates to transducers, and particularly to hand-held microphone devices. Where a microphone is to be used in situations that require repdy movement of the microphone, so as to make it impractical to utilize a conven- 5 tional support or microp-hone stand, it has been customary to provide what has been termed a hand-held microphone that may be laid upon a table, the floor, or any other convenient shelflike surface when not in use, and which is grasped 10 and held in the hand of the operator when the microphone is to be used. Hand-held microphones are, of course, intended for use in a close-talking relationship, and for this reasori most liand-held microphones are highly direc- 15 tional in Gharacter, and in the use of hand-held microphones as heretofore constructed, the inherent difhculties experienced in handling and orienting the microphone, so as to insure impingement of the sound directly on the diaphragm 20 of the microphone, have resulted in faulty transmission as well as objectionable delays in transmission, and to enable such difficulties to be avoided and eliminated is an important object of this invention. 25 Further @bbjects related to the foregoing are to ena@ble microphones to be so constructed that the user may quickly and easily grasp a microphone in such a manner that orientation of the microphone may be accomplished easily and 30 accurately and without loss of time so that in a practical sense the microphone is self-orienting, to eriable microphones to be so construgted and arranged that they may be readily grasped in the hand of the user in such a position that the 35 user may readily and easily deterniine the location of the sound receiving openings of the microplione, and to enable the connector cord that extends from the microphone to contribute to the selforienting properties or characteristics of 40 the device. A more specific object of the invention is to enable microphones to be embodied in a relatively long and narrow form so that the body that is thus aff orded may be readily grasped in the hand of the user, and a further and more 45 specii-ic object is to so locate the sound receiving openinp,,s of such a microphone at one end of an elongated body that is adapted to be grasped in the hand of the user so that when this body is thus grasped, the user will at once know that 50 the sound receiving openings of the microphone are located in a particular end of the body. In those instances where the user may be required to support a hand-held microphone in an ' operating position for long periods of time it is 55 highly desirable that the user's arm and hand be disposed in a natural or normal position so as to thereby avoid strain and fatigue, but in hand-held microphones as heretofore constructed it has been impossible to attain this desirable result. Thus, in prior hand-held microphones, the form and relatioiiship of the parts has invariably required that the user grasp and support the microphone with the palm of the user's hand faced toward the user's mouth. This required twisting of the hand and lower arm to a strained and unnatural liosition, and as a result it has been found that objectionable fatigue and strain are imposed upon the user. It is therefore a further object of this invention to enable hand-held microphones to be supported in an operative relation to the user's mouth while the user's hand and arm are disposed in a natural or normal holding position. A related object is to enable such a hand-held microphone to be grasped in a normal encircling relation by the hand of the user and to be sup-ported il'i the desired operative relation to the user's inouth while the thumb-side of the hand is disposed adjacent to the mouth. In many uses of hand-held mirrophones, it is customary to embody a control switch as a part @of the microphone so that by manipulation of this control switch, the operator may render the microphone or the associated transmitter, or both, operative or inoperative at will, and a furfher object of the present invention is to silnplify the operation of such a control s,@7itch as embodied in a microphone. Another and related object is to embody control switch means in a microphone in such a manner that the switch may be readily operated by the user as soon as the microphone is picked up in a normal manner. A further object is to enable a microphone to be constructed in an elongated form adapted to be grasped in the hand of the user and to locate the switch control member on the side of the elongated body so that the coiitrol switch may be readily operated merely by squeezing the elongated member as it is normally grasped in the hand -of the user. Where communications equipment such as a microphone is to be used in warm and humid climates, it is essential that switch means as well as the other electrical elements of the microPhone be effectually sealed against the entrance of water or water vapor, and to enable this to be accomplished in a sirnple and expeditious manner is a further object of the present invention. Another object related to the foregoing is to enable a microphone and a control switch therefor to be so mounted and related that a con-
[2]3 trol switch as well a-s the microplione are effectually sealed against the entrance of water or water vapor, and a further and related object is to enable a inicrophone, a control switch means and an impedance matching transformer to be so related and housed as to protect the operative electrical elements thereof against water or water vapor. When hand-held microphones of the character to which the present invention relates are in service In the field, it often becomes necessary to replace or repair some of the parts thereof, and particularly, it beco@nes necessary to replace the connector cord whereby the microphone is connected to the transmittin.- or other related apparatus, and to facilitate and simplify such repair or replacement operations is a further object of ti,iis invention. In the event that hand-held microphones of the kind to which this invention relntes are to be used in tropical climates, the electrical elements thereof must be ef-rectually sealed against the action of water and water vapor, and to effect such sealing of the parts requires exceptionally skilled workmen. Therefore it is desirable that this sealed relationship be maintained at all times, and that the sealed relationship be eff ected in such a manner that the usual servicing operations may be performed without disturbing the sealed relationship of the major parts of the device, and to enable this to be accomplished is another object of the invention. A more specific object is to mouiit the microphone element of a hand-held rnicrophone device in such a relation that it may be readily removed from a sealed relationship for repair or replacement, and another and related object is to afford a hand-held microphone device embodying terminal means and switch means in such association with a microphone that either the microphone or the connections to the terrqinais may be repaired or replaced without disturbing the sealed relationship of the switch means. When a connector cord is extended into the casin@ ol' a hand-held microphone or the like so O's to connect the wires of the cord to terminal means with;@n the housina, it is desirable that a seal be aff ordecl about the connector cord so as to prevent entrance of water or water vapor into the space where the wires are connected to the terr(linal means, and to enable this to be accomplished in a simple and effective manner is still another object of the present invention. Other and further objects related to the foregoi-ng are to enable a connector cord to be firm ly gripped at the point where such a cord enters a terminal charaber of a hand-held r-qicrophone device or the like, thereby to prevent endwise withdrawal of the cord, and to enable such a grippin,,- of the cord to be accomplished without twistin@:, of the connector cord, thereby to avoid tei,isiowon the connections between the wires and the terminals. More specifically it is an object to p@.-ovi.de a releasable gland for embracing a connector cord at the Doint where such a cord enters -.@ terminal housing or the like, and to enable such a @land to be tightened by rneans of a screw threaded member that is so associated with the other elements of the gland that the desired sealing and gripping action is attained without imparting rotative or twisting movement to the cony).ector cord. Other and further objects of the present invelition will be apparent from the following descript-Ion and claims and are illustrated in the accompanying drawings Nvhich, by way of illus2,485,278 4 tration, show preferred embodiments and the principle thereof and what we now consider to be the best mode in which we have contemplated opplying that principle. Other embodiments of the invention embodying the same or equivaleni principle may be used and structural changes may I)e i-r@ade as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. 10 In the drawings, Fig. I is a perspective view of a hand-held microphone embodying the features of the invention, the hand-held microphone being shown in an operative relationship to-.the mouth of a ],g user; Fig. 2 is a longitudinal sectional view shown at full scale and illustrating the relationship of the rfticrophone device to one form of noise shield that may be used in association therewith, the noise shield having been rotated slightly with respect to the position shown in Fig. 1; Fig. 3 is an end eievational view of the noise shield; Fi@-. 4 is an enlarged front elevational view of the microphone device with the noise shield removed; Fig. 5 is a side elevational view of the microphone shown in Fi,. 4; Fig. 6 is an end elevational view of the upper end of 'the microphone device shown in Fig. 4; Fig. 7 is a Ion.-itudinal sectional view taken on an enlarged scale along the line 7-7 of Fig. 4; Fig. 8 is a sectional view taken substantially along the line 8-8 of Fig. 7 and showing the manner in which the control switch means and the other elements of the microphone are mounted in one section of the casing; Fig. 9 is a view similar to Fig. 8 and taken along the line 9-9 of Fig. 7 so as to show the I other section of the casina and the marmer in which the switch control member is mounted in this section of the casing; Fig. 10 is a sectional view taken substantially along the line I 0- I 0 of Fig. 4, 4@5 Fig. 11 is a sectional view taken substantially along the line I I -I I of Fig. 4; Fig. 12 is a sectional view taken substantially along the line 12-12 of Fig. 9 and illustrating details 6f the retaining ring and the transducer 50 terminals; Fi-. 13 is a view taken in section substantially alon; the line 13-13 of Fig. 12; Fig. 14 is a side elevational viev,7 of one form of microphone unit that may be utilized in the hand-held microphone of the present invention; 55 Fig. 15 is a longitudinal sectional view taken substantially along the li-,le 15-15 of Fig. 14; Fig. 16 is an end elevational view of the soundreceiving end of the microphone shown in Fig. 14; @Fi-. 17 is a transverse sectional view substan-0 tially' along the line 17-17 of Fig. 15; and Fig. 13 is an enlarged fra.-Mental cross seetional view taken substantially along the line 18-18 of Fig. 16 and illustrating the manner in which the electrioal connections are established 65 betwep-n the voice coil and the terminais of the microphone. For purposes of disclosure the invention is herein illustrated as embodied in a hand-held microphone device 20 that has its coniiector cord 70 21 extended from one end thereof while the sound-receiving or sound sensitive mear@s 22, including a noise shield 23, aTe arranged at the other end thereof so as to face axially away from the end to which the cord 21 is connected. The 75 hand-held microphone -device 20 of the present
[3]5 invention has the body thereof constructed in an elongated form and of such size and dimeiasions that the device may be readily grasped in the user's hand, as shown in Fig. 1, and in accordance with certain aspects of the invention, coiitrol switch means are afforded within the body of the device and are operable by laterally project'-ng switch operating means 24 extended along one side of the body of the device so as to be readily engageable by a portion of the user's hand in any rotative relationship in which the device may be grasped. When the microphone device 20 is thus grasped, it may be readily and easily supported with the sound sensitive means 22 and the noise shield 23 in an operative relationship to the user's mouth, as shown in Fig. 11 and the switch operating means 24 may be operated at will by a mere contraction or squeezing action of the hand. In providing the hand-held microphone device 20 of the present invention, a sectional housing 25 that is preferably of generally cylindrical external form is made from a rigid insulating niaterial such a,-, Bakelite to afford elongated sections 25A and 25B that are separable substantially in a central longitudinal pla-ne indicated at 25C in Fig. 5 of the drawings. The sections 25A and 25B are held together by securi-ng means such as a self-tapping screw 20 that is extended through a bore 29 in the section 2rB and istapped into a bore 30 in the section 25A, as shown in Fig. 7 of the drawings, and when the screw 28 is in its final position, the head thereof is loc,-ited within a clearance recess 31 formed in the section 25B. After the sections 25A and 25B are Dlaced in their assembled relationship as shown in Fig. 7 of the drawings, the opposite ends thereof are covered by end caps 35 and 36 that are made from metal and are of generally cupshaped form so as to be movable in an endwise direction into an encircling relationship with respect to the opposite end portions of the cqsing 25. The end of the casing 25 that is embraced by the end cap 35 is so formed as to afford a mounting chomber 40 within which a microphone unit 41 is positioned, and the chamber 40 is afforded by matching recesses formed in the casing sections 25A and 25B. The recess 40 opens outwardly or longitudinally through the end of the casing 25 so that when a microphone unit 41 is disposed in position within the chamber 40, the soundreceiv"*ig openings 42 of the microphone unit moy face outwardly toward soundreceiving openings 43 formed in a dome-shaped central portion 35A of the end wall of the end cap 35. The chan-iber 40 terminates in a bottom surface .44 that constitutes one side of a division wall 45 that separates the chamber 40 from another mounting chamber 50 that is formed in the casing 25 by matching recesses 50A and SOB formed respectively in the sections 25A and 25B. The mounting chamber 58 constitutes the chamber in which associated electrical elements are to be disposed, and in the present instance such associated electrical elements include an impedance matching transformer 51 and switch means 52 that are operable by the switch operating means 24. Tiie impedance matching transformer 51 and the switch means 5i are associated with each other and with the connector cord 21 and the microphone unit 41 in a manner which will hereinafter be described in detail, and circuits are extended therefrom to terminal means 55 that are housed within a terminal chamber 56 that is 2)486.278 6 provided by the end cap 36. Ilence, when the end cap 36 is removed from the position shown in Fig. 7, the terniinal means 55 are exposed for such servicing operations as are required, and this may be accomplished without disturbing the other elements of the device. In affording the terminal chamber 56, the section 25B of the casing is terminated at 57 just within the edge of the end cap 36, while the sec10 tion 2 5A has an integral extension 2 5' that serves as a mounting for the terminal means 55 and also as means for enabling the end cap 36 to be secured in the desired position on the end of the casing 25. Thus, the extension 25' of the casing 15 section 25A has a laterally facing recess 60 formed therein and this recess is shouldered at 61 to afford a mounting face for an arm 62 of an angle bracket 63. The arm 62 of the angle bracket, in effect, comprises a relatively large 20 plate having an opening 62' folrmed therein so as to open into a chaml>er 60A that in reality constitutes an extension of the recess 60. The chamber 60A has an opening or passage 65 extended through the material of the casing section 25 25A and into the recess 50A, and within the recess 50A the passage 65 merges into a longitudinal groove 65A formed along the bottom of the recess 50A so that wires may be extended through the recess 50A beneath the transformer 51 and switch ,,, 0 means 52. Thus it is possible to extend connecting wires from the electrical means within the chamber 50 to the chamber 60A, and within this chamber, such wires are connected to electrical terminals 69 that are carried on a fibre ,3 @-) insulating plate 70 that covers the opening 62' in the plate 62. The terminals 69 are secured in place on the insulating terminal plate 70 by integral tubular rivet portions or extrusions and the necessary electrical connection between a wire 4(j and a tern-iinal 69 is effected by passing the wire through the tubular rivet portions and solderiiig the same so as to close the opening in the tubular rivet as indicated at 69' in Fig. 8 of the drawings. The insulating plate 70 and the mounting plate 45 62 are secured in position on the shoulder 61 by drive-screws 71, or self - tapping screws may be used in place of drive-screws in this instance as well as ihe other cases where drive screws have been shown or described. The mounting bracket 50 63 has a second arm 75 that serves as a support for a connecting gland 76 that includes means for clamping the end cap 36 iii place aiid also includes means for clamping the connector cord 21 in the desired position at its point of entry into 55 the terminal chamber 56, as will hereinafter be described in detail. In accordance with the present invention, all of the electrical eleinents that are permanently mounted in the device are mounted on the sec60 tion 25A of the casing so that asseilibi of the . y device is thereby facilitated. Thus the transformer 51 and the switch means 52 are permanently mounted within the recess BOA in the casing section 25A, as shown in Tligs. 7 alid 8, and 65 this mounting is accomplished in such a manner that when the two casing sections 25A and 25B are assembled, the switch means 52 are disposed in an operative relationship with respect to the switch operating means 24. Thus the switch 70 means 52, which in the present instance includes two switches 52-1 and 52-2, are disposed in the recess 50A near the end thereof that is adjacent to the chamber GOA. Such switch means may of course take many different forms, but as herein 75 shown, the switch means are of the over-center
[4]7 type. Thus the switch means include a mounting block 80 seated in the deep pdrtion of the recess 50A and having a mounting bar Of @along its upper edge, and the mounting bar-8 I has 7its ends rested upon pedestals 82 formed opposite sides of the recess SOA on ?the shoulder 82' so that securing means such as drive-screws 83 may be extended through the ends 81 and into the pedestals 82 so as to secure the switch means -52 in place. Each switch of the switch means @52 includes a stationary contact 84 that is in the form of a blade extended through the mounting block 80 to expose one end 84' thereof for connection with a wire that is to be associated with the switch. Each switch also includes a movable contact blade 85 that is also extended through the block 80 as at 85' to afford terminal means for connection with the wire or the like. The raovable contact 85 is adapted to be bent or shifted fror@i the normal open position shown.in Fig. 7 to a closed position wherein it engages the stationary con'uact 84, and this is accomplished by an over-center sprin.- 87 that has one end thereof Pivoted to the end of the movable contact 85 while the other end thereof is pivoted to an operating spring arm 88 mounted in the mounting block 80. When the operating spring arm 88 is moved to the left in Fig. 7, the movable switch contact 85 is also forced to the left until the back face thereof comes into contact with an abutment plate 89 that is carried in the mounting block 80, and after the movement of the arm 88 has progressed to such an extent as to move the upper end of the- spring 87 substantially to the left beyond the position of the lower end of the spring 87, the overcenter action of the spring causes the movable contact 85 to be quickly shifted to the right and into its closed relationship with respect to the stationary contact 04. SimilarlY, when the operating spring arm 88 is allowed to return in a right-hand direction toward the position shown in Fig. 7, the spring 87 again moves through its center position so as to quickly move the movable contact from its closed POsit,"Gn to its op-en position. The operation of the spring arm 88 is accorqplished by the switch operating means 24 in the nlanner that will hereinafter be described in detail. The impedance matching transformer 51 is disposed within the recess 50A in the casing section 25A in the space between the switch means 52 and the wall 45, and such mountina is accomplished by mounting straps 95 that are secured as by rivcts 95' to opposite ends of the core or laminationp, of the transformer 51. The other ends of the mounting straps are disposed on the ends of what may be termed pedestals 96 formed at adjacent ends of the ledges 82', and drive screws 97 secure these ends of the straps 95 on the tops of the pedestals 96. One of the windings of the transformer 51 has the leads 98 thereof .tssociated with the microphone unit 41 and in accomplishing such association, the leads 98 are extended to a pair of terminals 100 mounted in the recess 58A of the section 2@.A. The terminals 100 are secured on the lower face of the wall 45 as viewed in Figs. 7 and 8 by means such as rivets IO 1 that extend through the wall 4 5. The upper ends of the rivets 101 are arranged to secure terminal brackets 102 in position within recesses 103 formed in the upper face 44 of the wall 45, as will be evident in Figs. 7, 8 and 12 of the drawings. The rivets IO 1 extend the -electo the brackets 102, and these brackets 102 have angularly related terminal arms 105 formed thereon as shown in Flgs. 7 to 12 so as to extend upwardly along one side of the recess 40 in spaced gro(>ves 106. The terminal brackets 102 are n-iade from a spring material such as phosphor bronze so as to enable efficient contact to be made with the connecting terminals 107 of the microphone unit 4 1, and the upper ends of 10 the terniinal arms 105 are in position for engagement by such connecting terminals 107 when a microphone unit 41 is moved in an endwise direction into position in the chamber 40 as will hereinafter be explained. 15 Leads iC8A and IOBB from the other winding of the transformer 51 are extended toward the bottom of the recess 50A and into the groove 65A, and are then extended within the groove 65A toward the passage 65. In the present instance 20 the wire -108A is extended directly through the passage 65 and into the chamber 60A, and is connected to an appropriate one of the terminals 69. The other lead 108B however is extended beneath the mounting block 80 and is then ex25 tended out of the groove 65A and to the stationary contact'84 of the switch 52-2, to which it is connected as by soldering. The other or movable contaclu 85 of the switch 52-2 has a wire JOSA connected thereto as by soldering, and this 30 wire is led into the groove 65A and through the passage 65 and into the chamber 60A where it is connected to another one of the terminals 69. Wires 109C and IOSD are connected to the other two terminals 69, and are extended through the 3,5 passage C5 fron-i which they are further extended into the recess 50A and are connected respectively to the terminals 84 and 85 of the switch 52-1. Thus, the closure of the switch 52-2 closes circuit from two of the terminals 69 41) through one winding (>f the transformer 5 1, thereby to control circuit to the microphone unit 41, while closure of the switch 52-1 completes circuit between the other two terniinals 69. Such operation of the switch 52-1 may be utilized to 45 cause operation (>f relay means or the like for governing operation of an asso-ciated transmitter or other related equipment. The switch operating means 24 are mounted on the other section 25B of the casing so as to co50 operate with the spring arras 88 in effecting operation of the switches 52-1 and 52-2. Thus, the section 25B of the casing has an elongated slot II 0 formed therein so as to extend longitudinally of the casing, and an operating lever 55 1 1 1 formed from a rigid insulating material such as Bakelite is disposed in this slot so as to extend outwardly beyond the side of the casing section 25B. The operating lever arm I I I is supported on a xnounting plate I 1 2 that has ears I 1 3 60 formed thereon in spaced relation so that a pivot lug II 4 formed on the lower end of the arm I I I as shown in Fig. 7 may be disposed between the ears 113. A pivot pin 115 extends through the lug I 1 4 and into the ears I 1 3 so that the arm I I I 65 may be pivoted about the ax,@'s of the pivot pin II 5. The mounting of the lever arm I I I in the slot 110 is in the present case accomplished in such a manner as to seal the opening or slot II 0 against the entry of water or water vapor. This 70 is accomplished through the provision of a sheath 120 that is molded from a flexible material such as rubber so as to embrace the side surfaces and the outer surface of the lever arm I I I and the sheath also is formed to afford a flange 121 at trical eir@auits from the respective terminals 100 '75 the innermost edge of the sheath, and this flange
[5]2,485,278 9 121 is claniped against a shoulder 122 formed about the inner edge of the slot I I 0. Such clamping action is in the present case effected by the bordering edge of the mounting plate 112, this bordering edge being secured against the shoulder 5 122 by drive-screws 124, as will be evident in Figs. 7, 9 and 11 of the drawings. The lever arm I I I has a switch operating finger 125 formed thereon that extends through an opening 126 formed in the mounting plate 112, and as will be evideilt 10 in Figs. 9 and 11, this operating finger 125 is of such a width that it will engage both of the operating spring arms 88 of the two switches. The spring arms 88 act on the lever arm I I I to normally maintain the arm I I I in its outwardly pro- 15 jected relationship of Fig. 7, thereby to maintain the switch.means 52 normally open, and the strength of the spring action of the arms 88 is such that the switch means 52 will not be inadvertently closed as for in.stance when the device 20 20 is laid down with the switch operating means 24 in a downward position. Thus when the user applies a positive inward pressure to the sheatli 12 0, the arxn I I I is -Divoted about the axis If 5, thereby to force the spring arms 88 in a - switch- 25 closing direction. In order that damaae to the switch means may be avoided, a stop 3nger 128 is provided near the free end of the lever arm _ I I 1, and this stop finger is arra,nged to engage the mounting plate 112 when the lever arm " 1 3(@ has been moved for a distance sufficient to cause closure of the switch means. V,Then a hand-held microphone of the character to which the present iiivention relates is to be utilized in a tropical climate, it is desirable 3:0 that all of the electrical elements of the device be sealed against the entry of water or water vapor, and hence the association of the elements of the microphone device of this invention is accomplished in such a manner as to effect such .,,, desirable sealing of the electrical elements. It is particularly desirable that the electrical means included within the chamber 50 be permanently sealed against the entry of water or water vapor, and insofar as the switch operating means 24 45 are concerned, it will be evident that the provision of the sheath 120 serves to effect this result. In this connection however, it may be pointed out that a suitable sealing compound or adhesive means may be applied to the shoulder 122 be- 50 fore the sheath is clamped in place against this shoulder. Another path along which water or water vapor might tend to enter the chamber 50 is afforded along the separation line or plane 25C, and to simplify the provision of an effective 5,5 seal between the two sections 25A and 25B, an interlocked arrangement is provided about at least a portion of the border about the cavities that provide the chamber 50. Thus as shown in Fip,s, 7, 8, 9 and 11, a continuous ridge or rib 130 00 is provided about the sides and lower edge of the cairity 50A that is formed in the section 25A. this rib being bordered at its outer edge by a flat si.7rf-,Ace 131 that lie,,@ in the plane of separa,tion 25C. The section 25B has ,t flat surface 132 that 65 is adapted to have flat surface engagement with the bordering surface 131 of the section 25A, and inside of the bordering surface 132, the section 25B has a continuous groove 133 into Nvhich the rib 130 is adapted to -fit, as will be evident in Figs. 70 7 and 11. In the portions of the two sections 25A and 2513 that afford the upper end of the casing, the sections 25A gnd 25B are provided respectively with flat surfaces 134 and 135 that have a flat surface engagenient when the two 75 10 sections are in their assembled relationship. In the course of assembly of the two parts or sections 2 5A and 2 5B, it is preferable to apply a suitable adhesive or sealing cornpound along the sides of the cavities that form the chamber 40, and in a continuous line about the borders of the cavities 50A and 50B so as to cover at least a portion of the surfaces that -.re to be placed in abuttilig relationship, as indicated in Fig. 11, and hence when the two sections are drawn together by tightening of the self-tapping screw 28, the sealing compound will provide Pn effective and continuous sea] about the entire border portion of the chamber 50 and along the bottom and sides of the chamber 40. The seal that is thus afforded is maintained by the interlocking action of the rib 130 and the groove 133 which are in turn held in such interlocking relation by the screw 28. It will be recalled that the chamber 50 comrnun4cates with the chamber 60A through a passage 65, and hence, in order that the electrical means may be fully sealed, the mounting of the plates 62 and 70 across the face of the recess 60A i.@ accomplished in such a manner as to effectually seal the charnber ODA. Thus a suitable adhesive or sealing compound is placed between 'uhe plate 62 and the shoulder 6 1, while such a compolind is similarly placed between the abutting faces of the plate 70 and the plate 62. Thus when the two plates are secured in position by the action of the screws 7 1, the border portions of the chamber GOA are properly sealed. It will also be recalled that the rivets that serve to secure the terminals 69 in place originally have openings therethrough, but in the course of connecting the wires to the terminals 69, the soldering at 69' serves to effectually close and waterproof these openings. The openings through which the rivets 101 are extended are also sealed against passage of water and water vapor, and this is accomplished by application of a sealing compound or substonce about the rivets IO 1 and the terminals 100 and 102 when these elements are put in Place. Thus the chamber ODA as well as the chamber 50 are effectively sealed against the entry of water or water vapor. In associating the connector cord 21 with the rnicrophone device of the present invention, the end cap 36 is removed, thereby to exl)ose the co-nnecting arms of the terminals 69 so that the wires 2 1 A of the connector cord 21 may be connected as by soldering to the appropriate terminals 69. In this connection it will be observed that the end cap 35 has an axial opening 140 forw-ed therein so as to surround one end of an externally threaded nipple 141 that is secured as by spinning or staking the nipple in the lateral projecting arm of the bracket 63. The nipple 141 h,-@v means screw threaded thereon for clamping the end cap 36 in position on the end of the casing 25, and in this connection it will be -noted that the end cap 36 is so related to the other elements of the device that the terminal chamber 56 is sealed against water or water vapor when the end cap 36 is properly secured in position. Thus it will be evident in Fig. 7 of the drawings that an anpular washer 144 of a resilient materiol is disposed against an annular shoulder 145 on the casirig 25, and the washer 144 is so located that it will be engaged by the edge of the cup-shaped end cap 36 when the end cap is placed in p-osition. About the nipple 14 ( ond in abutment with the end wall of the end cap 36, another sealing washer 146 is provided in
[6]2,485,278 snugly -fitting relation to the nipple 14 1, and this resilient Njasher 146 is clamped against the end wall of the cap 36 by a metallic washer 147 and a clamping nut 148, the nut 143 being on the niPPle 141. The sealing gland 73 also 5 includes a clamping nut or member 150, and,,-,.,)ien the iiashers 146 and 147 and the nuts 143 and 159 are removed, the end cap 36 may be removed by endwise withdrawal along the axis of the nipple 14 1. The gland 7 6 utilizes the nut or thread10 ed sleeve 15-3 to apply clamping and sealin-. pressure to the connector cord 2 i, and for this purpose, the lower end of the nipple 141 is reamed to afford an inivardly tapering conical surface 152 against Nvhich an enlarged conical end por1,5 tion I 53 of a resilient sealing sleeve 154 '@s adapteil to engage. The nut 150 is flanged inwardly at 155 to afford an an.-ularly disposed shoulder -Lipon which a inetal@lic Nvasher i56 is disposed. The washer ll.'-g engages an annular abutment shoulder of the sleeve 154 so that by tightening the nut 150, the enlarged sealing end 153 of the sleeve 154 may be forced inwardly into the conic-al surface 152 of the nipple 14 1. Thus the sealing poi@- tion 153 is compressed or contracted so as to clamp the cord 21 and eff ect a tight seal about the surface thereof, and this is accomplished without objectionable rotative mgvement of the sleeve 154 and the connector cord 2 1. Thus twisting of the cord 21 with the consequent damage to 30 the connections with the termiiials 69 is avoided. The compression of the sealing sleeve 154 and the resultant clamping of the cord 21 serves to prevent endwise displacement of the cord. At the other end of the casing 25, the end cap 35 35 is so associated with the casing 25 and with the microphone unit 41 that objectionable entry of water or water vapor into the chamber 40 is prevented. Thus it will be noted that the eiid cap 35 fits down over the upper end of the cas40 ing as viewed in Figs. 7 and 8, and the lower edge of the end cap 35 is arranged to rest upon 9, resilient annular sealing washer 160 that in turn bears upon an annular abutment shoulder 161 formed on the two sections of the casing 25. 45 When the end cap 35 is thus positioned, it is held in a firmly clamped relationship with respect to the sealing ring or washer IGO by a retainin.- 3:lng 165 that is annular in character and which surrounds the side walls of the end cap 35. This re50 taining ring 16 5 has a pluralit37 of set screws i 6 @,@ extended therethrough, as,@vill be evident in Figs. 4, 5, 10, 12 and 13, and these set screws are enga--ed i@7ith matching recesses 167 formed in the w@lls of the casing sections 25A and 25B. It 55 be observed in Fig. 12 that tlle casing section 25A has a relatively wide rib 169 formed longitudina.Ily thereof opposite the grooves 106, thereby to afford Proper wall thickness adjacent these grooves, and the end cap 35 has 0, complemental 60 rib 170 formed therein to embrace the rib 161;1,. The outer surface of the securing ring ISE, is, however, truly annular in character, but the inner surface thereof is cut away as at 171 so as to Provide clearance for the rib 170 of the 65 end cap 35. The mounting of the end cap 35 on the casing 25 serves alsc) to hold the microphone unit 41 iii, position in the chamber 40, and the relationshi,o of the parts is such that the chai-pber P(, 70 is eff ectually sealed against the entrance of water or water v,-,por. As will hereinafter be described in greater detajl, the microphone unit 41 has a cap 175 that ;@s formed of Bakelite or like material so as to overlie the diaphragm 176 of the 75 12 microphone, and it is in the cap 175 that the sound-receiving openings 42 are formed. The diaphragm i 7 6 is of a waterproof construction so j@-, t--) t-',lereby protect the iiiternal elements of the unit 41 against the entry of water -,nd -@-,Tater vapor, and a sealed arrangement is a@@(ir@,,ed about the upper border portions of the cap 175 so that water or water vapor cannot pass into the chomber 41. Thus the cap 175 has a rib i75A about the area in which the openings 42 -,re forr@-led, such rib 175A be-ing annular in character as viill be evident in Fig. 10 of the dra@vings. INhen the microphone unit 41 is to be placed i-,.2 the chamber 40, a cushioning pad IT8 of rubber or c@l.her resilient material is placed in the bottom of the chamber 40 against the surfac@- @ll of the wall 45, and in many instances it mLy be desirable to secure this cushionin.@ pad in positirn by adhesive so as to insure against loss of the pad. The microphone unit 41 is moved crdv75se into position in the chamber 40, and in the course o-f such movement the terminals 107 of @he microphone unit are moved into operative cn,,ageir@n,@ the spring terminals 105. The .-@ouiitin.- operation thus described also moves the bj"@or@-i of th.- n-i,@'crophone unit 41 into abutment with the pad 170, -,T,7hich, it Nvill be noted, serves tc) i.-isiLL'a-Lc the unit from the rivets 101 and the ucrT@i4nal brickets 102, and after this has been l,tceoinplished, a sealing washer 180 of rubber or like riiotc,, i,-,l is placed in such a position that it engages the upper edge of the flange 175A as ,is t7le upper ed-es of the walls that define the cha-,iiber 41,1. In this conenction it should be notcd that the sealing washer 180 is of such a form thct i-t extends onto the top of the rib 169, thereby to effectlially close the upper ends of the slots The end cap 35 is then put into positi-on and is forced downwardly so as to compress the lower sealing ring 100 and the - Lipper sealing ring @(lig, there also being an incidental compression of the pad 1'73 - ,7ihich serves to hold the led,e ITC)A firmly against the sealing ring 180. Th@is the chamber 40 is sealed against the entry of vvater or water vapor, and the electrical elements such as the t,-rmipals 105 are protect-,d aga4.nst ,iiay undesirable action that might result fi,oin the presence of such w-,Lter or 'water vapor. When thr@ two metallic end caps 35 and 36 are thus s@,cured in place on opposite ends of the casing 25, they serve i'lot only as additional means for preventin-,7 separation of the casing sections 2.@A and 2'@B, but also as a protecting means about the ends and end edges of the casing, and hence the end caps strengthen the assembly and preveii4@, damage that might otherwise be caused by blovvs s'@riking the ends of the device. The cia-@,npi@-ig or fastening ring 165 also serves as a part ol the r@,iounting means for removably srz:curiii, the noise shield 23 in position on the ricrop@@,one device, and as will be evident in Fig. 2 of the drawin@s, the noise shield 24 has a sleeveIii-@e portion I f@u that s rrounds the side wall of the end 'Cap 35, and thuis sieeve-like portion 185 has an internal groove 186 formed near one end "hereof that embraces the securing rin- 105, th@-reby to hold the sleeve-like portion in p@sition on the microphone device. At the other end of the sleeve-like port-Ion 185, the noise shield 21@ includes a flared portion f 88 having its end edges !,38A formed in such a manner as to be adapted to embrace the surfaces of the user's face about the mouth as shown in Fig. 1, thereby to exclude outside noise. The noise shield 23 has a plurality of Pressilxe reliej@L openings or passages 190 formed
[7]13 therein whereby air pressure within the noise shield 23 is relieved while entrance of objectionable noise from the outside is prevented. It will be recognized that under the broad aspects of the present invention, the character or type of the microphone unit 41 as -@vell as the noi.-,e shield 23 may take difj.'erent forms, but as herein illustrated, the microphone unit 41 is so constructed and arranged that it is in eff ect complemental to the specific construction of the noise shield 23 insofar as frequency response characteristics may beconcerned, and the joint action of the particular microphbne unit 41 and the noise shield 23 is such as to -produce a substantially flat frequency response curve throughout the normal range of speech frequencies. In the form that is herein illustrated, the microphone unit 41 is of the dynamic or moving coil type, and as shown in Figs. 14 to 18 of the drawings, this microphone unit co,-nprises a cup-like outer shell or housing 200 having integral annular side Walls 201. Adjacent the upper end of the side walls 20 1, an internal annular shoulder 202 is provided, and above the shoulder 202, the wall 201 is relatively thin as indicated at 201A in Fig. 15 of the drawings. The shoulder 202 is disposed in a plane parallel to the inner surface 204 of the bottom wall of the housing 200, and a cylindrical permanent magnet 205 is rested on the surface 204 of the bottom wall so as to be concentric with the shoulder 202. The magnet 205 is preforgbly secured in position on the surface 204 by soldering the same to this surface as indicated at 206. The housing 200 is made from a soft iron material so that it constitutes a part of the magnetic circuit of the microphone, and the upper end Df the magnet 205 constitutes the inner pole of the magnetic circuit. . The outer pole of the magnetic circuit is provided by a soft iron pole plate 208 that has a ceiitral Gpening 209, Fig. 18, formed therein so as to be spaced frorn the magnet 205 and thereby afford an annular magnetic gap. The outer pole plate 208 is fitted into the upper end of the housing 200 so as to rest upon the shoulder 202, and in order that an upward annular rim or ledge 208A may be afforded about the upper surface of the plate 200 for supporting the diaphragm 176 in a spaced relation to the plate 208, the plate 208 is formed or coined so as to be offset about its outer edge, thereby to also provide a rabbeted annular groove 208B about its lower outereorner. Thisr,.tbbetedannulargroove2C8B fits over the shoulder 202. Before the outer pole plate 2 08 is put in position in the housing 200, means are mounted within the annular space about the magnet 205 for coiqtrolling t@ie response characteristics of the microphone, and in the present instance such means are relatively simple in character. Thus a molded washer-like member 212,made from hard rubber or other moldable materiai is put in position about the magnet 205, and this member 212 serves to accurately define a back chamber and limit the volume of air that is trapl)ed between the upper surface 212A of the member 212 and the lower surface of the outer pole plate 208. After the outer pole plate 208 has been put into position, the diaphragm 176 is mounted in position so as to be supported upon the annwa,r ledge 208A. In the form herein shown the diaphragm 176 is made in two parts from a waterproof m-,tterial such as molded paper pulp having a waterproofing ingredient such as a thermo-setting resin included therein. The diaphragm 176 thus in2,485,278 14 tion 176A, the outer border of which is seated upon and secured as by adhesive means to the upper face of the annular ledge 208 A. The inner edge of the annular flexing portion i 76A has a generally cylindricai portion 176B formed thereon in an relationship so as to afford a voice coil support. This cylindrical portion 176B has an annular offset or shoulder 176C formed therein so that on the outer surface of the cylindrical por10 tion 176B, the offset 176C affords a guiding shoulder against which one end of a voice coil 215 may be wound. The annular portion @76B is so disposed on the flexing portion 176A that the voice coii 215 is disposed within the annular magnetic 1,3 gap formed between the surface 209 and the magnet 205. After the flexing portion 176A has been secured in position on the annular ledge 208A in a properly centered relationship which centers the voice coil with respect to the axis of the magnetic gap, a dome portion 170D having a cylindrical flange 176E at its outer edge is inserted into the cylindrical portion 17 6B, and such inserting movement is limited by engagement of the flange 176E with the offset 976C. The dome 176D is of course 2i5 secured by a waterproof adhesive in the position that is thus determined by the offset 176C, and thus the waterproof diaphragm is completed. The ends 215A of the voice coil 215 are extended upwardly through the flexing portion 176A of the 30 diaphragm in a sealed waterproof relation there b,@-ing a waterproof substance applied to the wires and the diaphragm at the Points where the wires extend through the diaphragm, and the wires are theii extended outwardly in a generally radial 35 directlen along the upper surface of the flexing Portion and are secured thereto by adhesive means. Th,- outer ends of the wires 215A are extended substantially beyond the edge of the flexing portion 176A for connection with the termi40 nals 107 as will now be described. The terminals 107 are mounted in an oiitwardly extending terminal block portion 17-5B of the cap 175, and provision is made for extending the wires 215A outwardly beneath the edge of the cap 175 in a sim4 -j ple and effective manner. Thus it ivill be noted in Figs. 15 and 18 o.L the drawings that the cap 175 has an outward extension or flange 220 about its edge and this fiange has a downwardly extending annular flange 221 formed at its outer edge. 50 The cap 175 is ins6rted in the upper end of the wall 201A so that the flange 221 bears Lipon the border portion of the diap@hr,,tgm to hold the same down against the ledge 208A, and it will be observed that the radially projecting terminal block @ 5 175 extends through a slot 223 forrled in the rim orupperedgeofthewaII201A. Afterthecaphas been put in position as just described, the upper edge of the wall 2 0 1 A is flanged inwardly as indicated at 225 so as to overlie the flange 220 of the (i( cap, 175 and thus the cqp 175 is held in position. It will be observed that when the cap is in this position, the downwardly extetiding flange 221 on the cap provides an appreciable clearance space 22S above the flexing portio@n of the diaphragm 65 176. In extending the wires 21,5A outwardly for association with the terminals 107, it sholild be observed that down@vard@,,y facing notches 230 are @ormed in the flonr,,e 221 and these notches extend outwardly into vertically extending grooves 231 70 formed in the out(Ir face of the terminal block portion 175B. TIlese vertical grooves extend Lipwardly so as to enter the respective bores 233 in which the slaanks 107A of the terminals 107 are to be driven. Th,,is when the wires 215A are led cludes a substantially flat annular flexing por- 75 outwardly through the notches 230, they are then
[8]15 extended upwardly through the grooves 231 and are wound about the respective shanks of the terminals 107 which are at this tirre partially insertedintothebores233. Thewiresmaythenl)esoldered to the shanks if desired, after which the terminals 107 are driven completely into the bores 233, such inward movement being limited by elalarged spacing shotilders 107B formed on the terminals 107. The microphone device of the present invention is normally shipped in completely assembled relationship so as to iliclude a connector cord 21 in an operative relationship to the device, and hence the initial associatioii of thcmicrophone device with a transmitter or the like is accomplished merely I)y establishin, the desired connection between the other end of the connector cord and the equipment with which the device is to be used. In the use of the device the operator may rely upon the self-orienting characteristics of the microphone as afforded by the p,:esent invention, and when the microphone device is to be used, the operator merely grasps the elongated body of the device in the manner shown in Fig. 1 of the drawings. When the bc)dy of the microphone device has been encirclf-,d by the hand of the user, the switch operating means 24 are invariably in such a position that they may be readily operated merely by a squeezin- action of the user's hand. In the course of the movement of the device from the floor or other location -%vhere it has been positioned diiring an idle period, the retarding action of t'he cord 21 as the operator lifts the micropholle toward his face serves to cooperate with the elongated form of the microphone device to indicate which end of the device constitutes the sound-receiving end thereof, and hence, by the time the device has been r,,loved relatively close to the user's mouth, the us@-r will know which end of the device is to be moved into ouerative relationship with respect to the mc>iith. It ,,iill be clear therefore that as soon as the microphone device has been moved relatively close to the mouth of the user, it will invari,ably be possible for the user to locate the microphone device in a proper position so that transmission may start immediately. The fact that the switch operating means 24 is at this moment invariably positioned so that it may be operated also contributes to the efficiency of operation that may be attained with microphone devices constructed under the present invention. The characteristics of the switch operating means 24 of the present invention that enable this switch operating means to be actuated by a squeezing action of the h-and also imdart to the present microp',ione device an added range of usefulness, for it will be apparent that the switch operating means 24 may readily be operated even though the user may be wearing reiatively heavy gloves. The microphone device of the present invention is also capable of being serviced in a relatively easy and efficient manner, and this may be accomplished without disturbing the sealed relationship of the eledt,,ical elements that are disposed @,,7-4thin the mounting chamber 50. Moreover, it will be evident that the microphone unit P, I -r,,iy be removed and replaced in a relatively siml,le manner and this may be accomplished V,Tithout disturbing the sealed relationship of the terminal chamber 56. Furthermore, the connector cord may be readily replaced by opening the terminal chamber 56, and this may be accomplished without disturbing the sealed relationship of the microphone 4 1. The servicing operations in respect to the connector cord 21 are materially 2,485)278@ 16 of the sealing gland 76 which not only clamps the connector cord 21 but aiso produces the desired seal about the cord so as to prevent entry of water or water vapor. The sealing and clamping action that is thus accomplished by the gland 76 is cff ected in such a way that objectionable rotative n-iovement of the cord is avoided, and this, taken in connection with the clamping action that is exerted on the cord 2 i, serves to prevent unde10 sirable stresses upon the connections that have beenestablished between the wires 21A and the terminals 69. From the foregoing description it will be evident that the present invention materially simpli15 fies the problem of attaining rapid and efficient transmission wih microphones of the hand-held. type, and it will also be evident that the microphone unit of the present invention is in effect self-orienting so as to enable the microphone to 20 be readily grasped and used for transmission purposes when this is required. The hand-held microphone device of ti-ie present invention is of such a character that it may be supported in the desired operative relationship to the user's mouth 25 without placing the hand and arm of the user in an unnatural or strained relationship, and because of this, the microphone device of the present invention may be used for relatively protracted periods without undue strain or fatigue. 30 it will also be evident that the hand-held microphone device of the present invention attains an effective sealing of the electrical elements thereof in a simple and highly effective manner; and it will be clear that this sealing 35 action is attaiiied in such a way that the normal servicing operations that must be performed upon devices of this character may be accomplished without disturbing the sealed relationship of most of the elements of the device. 40 The hand-held microphone device of the present invention also ma'uerially simplifies the operation of switch means that are in some instances associated with hand-held microphone devices, and in accordance with the present invention, such switch means may be readily and easily oper45 ated as soon as the user has grasped the device in the normal manner. Thus, while we have illustrated and described the preferred embodiment of our invention, it is to be understood that this is capable of variation and 50 modification and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims. 55 We
