US2235722A

US2235722A - Radio tuning device

Info

Publication number: US2235722A
Application number: US275097A
Authority: US
Inventors: William H Murray
Original assignee: Individual
Current assignee: Individual
Priority date: 1939-05-22
Filing date: 1939-05-22
Publication date: 1941-03-18
Anticipated expiration: 1958-03-18

Description

- March 18, 1941. w. H. MURRAY RADIO TUNING DEVICE 4 sheets-sheet 1 Filed May 22, 1939 3mm WHMarrag I N 'gil SSN UT @www March 18, 1941. w. H MURRAY 2,235,722

RADIO TUNING DEVICE Filed May 22, 1939 4 Sheets-Sheet 2 l 4530/54 4530 155 4530 /z-i-S 79 WI' il om 4W 94M NORM/.54,

i 47 WHMW@ March 18, 1941. w, H, MURRAY 2,235,722

RADIO TUNING DEVICE Filed May 22, 1939 4 Sheets-Sheet 5 gz WHMur-ray 4 '5 @a s( @www March 18, 1941. w. H. MURRAY RADIO TUNING DEVICE Patented Mar. 18, 1941 UNITED STATES PATENT OFFICE Claims.

This invention relates to radio tuning devices and more particularly to an automatic time controlled device for use in combination with a radio receiver having automatic station selecting means 5 associated therewith.

An object of this invention is to provide a time controlled means in combination with a push button tuning device incorporated in a radio for automatically tuning the radio receiver to a selected station at a predetermined time.

Another object of this invention is to provide an electrically operated radio tuning actuator and means controlling operation of the actuator at a predetermined time.

A further object of this invention is to provide a radio tuning means of this kind which is so constructed that one portion of the device may be operatively connected to the radio set and another portion of the device may be disposed remote from the radio set for controlling the operation of the radio set from a remote point and at a particular time in order that a particular radio station may be tuned in by the radio receiver at a predetermined time.

A still further object of this invention is to provide a time controlled and electrically operated ,tuning means in combination with an automatically operated radio tuning control, the device being so constructed that any desired number of radio stations may be tuned in at intervals selected by the user of the device, the intervals being co-ordinated with the beginning of the broadcast of the selected radio stations.

A further object of this invention is to provide in a device of this kind an automatically operable time controlled tuning means including a solenoid operated circuit making and breaking means and also solenoid operated circuit breaking means associated with the first circuit making and breaking means so as to prevent oscillation of the first circuit making and breaking means.

Another object of this invention is to provide in a device of this kind a controlling switch whereby the device may be readily cut off in order to permit manual operation of the radio apparatus.

To the foregoing objects and to others which may hereinafter appear, the invention consists of the novel construction, combination and arrangement of parts as will be more specifically referred to and illustrated in the accompanying drawings, wherein is shown an embodiment of the invention, but it is to be understood that changes, variations and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

(Cl. Z50-20) Figure 1 is a vertical section of a radio tuning device constructed according to an embodiment of this invention mounted on a radio shown in fragmentary side elevation,

Figure 2 is a vertical section of the control 5 means for the operator shown in Figure 1,

Figure 3 is a sectional View taken on line 3-3 of Figure 2,

Figure 4 is a diagrammatic view of the electric circuits embodied in this invention, l0

Figure 5 is a fragmentary Vertical section partly in detail taken on line 5-5 of Figure 3,

Figure 6 is a vertical section partly in detail taken on line 6-6 of Figure 3,

Figure 7 is a fragmentary side elevation of the 15 structure shown in Figure 2,

Figure 8 is a fragmentary sectional view on an enlarged scale taken on the line 8-8 of Figure 3,

Figure 9 is a longitudinal section taken through a modified form of this invention, 20

Figure l0 is a fragmentary plan view of the circuit closing means embodied in the structure shown in Figure 9, and

Figure 11 is a vertical section through the drive means incorporated at one end of the structure 25 shown in Figure 9.

Referring to the drawings, the numeral I5 designates generally a radio cabinet including a push button or lever operated tuning means I6. The tuning means I6 at present forms a part of 30 the radio apparatus I5 and in the present instance, the tuning means I6 is constructed in the form of a push button although if desired, the tuning member I 6 may be a pivoted or slidable tuning means. A housing I'I is mounted in face 35 abutting relation to the front of the cabinet I5 and comprises a front wall I8, a rear wall I9 provided with an opening 20 through which the tuning operator I 6 is adapted to project. A top wall 2I is secured to the side walls I8 and I9 and the 40 end walls 22 and a bottom wall 23 is secured to the lower ends of the front and rear walls I8 and I9 and the end walls 22.

A plunger `or slide member 24 is slidable in a bearing or cylindrical bushing 25 secured to the 45 fron-t wall I8 and is provided at its forward end with a head 26 disposed in confronting rela-tion to the button or tuning operator I6. A lever or plunger operator 2l is rockably mounted on a shaft 28 carried by the housing I'I and is provided 50 with an elongated slot 29 through which a pin 30 engaging through la slot 3| in the plunger 24 is adapted to engage. The pin 30 engages against one end of a spring 32 positioned about the plunger 24 and the opposite end of the spring engages 55 against the head 25. A solenoid coil 33 is secured in depending relation to the top wall 2| of the housing |1 and a movable core or armature 34 engages within the coil 33 and is provided at its lower end with a head 35. The core 34 is adapted to gravitationally move downwardly to an inoperative position. The lever or arm 21 is provided with an angularly 4disposed arm or extension 36 which extends downwardly from the shaft 28 and the extension 38 is connected to the solenoid 34 by a link 31. The link 31 is pivotally connected as at 38 to the lower end of the arm or extension 35 and pivotally mounted `as at 39 in a slot 48 provided in the lower side of the head 35. In this manner when the core 34 is drawn upwardly by the solenoid coil 53, the -plunger 34 is moved forwardly and to the left as viewed in Figure 1 for engagement with the tuning operator I8.

The operator hereinabove described which is mounted in the housing I1 and engageable with the tuning button I8 is adapted to be electrically connected to a time controlled tuning device shown in Figures 2 to 8 inclusive, the operator being interposed in the electric circuits shown in Figure 4, to be hereinafter described.

The tuning operator l1 shown in Figure 1 is electrically connected with a selective and time controlled tuning device generally designated as 4| which comprises a cylindrical s-tationary housing 42 mounted lon a base 43. rIhe housing 4| is provided with a top wall 44 which is secured to the upper end of the cylindrical member 42. The cylindrical wall 42 is provided with a plurality of circum-ferentially spaced apart openings 45 which are arranged in a plurality of vertically spaced apart ser-ies 45a, 45h, 45e, 45d, 45e and 45j, the number of rows of openings 45 corresponding to the number of buttons carried by the radio apparatus I5. The wall 42 on the inner side thereof is provided with a circular band 48 for each series of openings 45 and leach band 46 is provided with openings 41 registering with the openings 45. A pair of yieldable clips Vor clamping members 48 are secured to the inner surface or side of the band 46 and :a metallic key or pin 49 is adapted to be inserted through the openings 45 land 48 and is provided at its inner end with a groove or clip engaging portion 58 which is positioned outwardly from a rounded head or contact 5| carried by the inner end of the pin 49. The outer end of the pin 49 is provided with a button or knob 52 preferably, of insulated material so that the key or pin can be handled without shocking the person handling the key.

Each row of openings 45 has a band 45 associated therewith and clips or holding members 48 mounted on the inner side thereof for engagement with a key 49. The holes 45 are `arranged in such a manner that the space between each pair of holes is equivalent to a predetermined time and in the present instance, this time is fteen minutes, being a period of Itime during which certain radio broadcasting stations are :operating on a particular broadcast. A cylindrical member 53 is disposed interiorly of the hou-sing 4| and is provided with an upper wall 54, the cylindrical member 53 and the wall 54 being for-med of insulating material. A vertically disposed shaft 55 is rotatably mounted at its lower end in a bearing 55 carried by the base 43 and a second shaft or extension 51 is coupled to the upper end of the lower shaft 55 by an insulated coupling member 58. The shaft extension 51 is provided with threads 59 and nuts 88 .and 8| are threaded onto the threads 59 and engage the top wall l54 of the cylindrical member 53 so as to tightly secure Ithe cylindrical member 53 to the shaft member 51 for rotation thereby.

A worm gear 82 is secured yto the upper end of the shaft member 51 and a worm 83 operated by a clock mechanism 34 engages the worm gear 62 so as to rotate the cylindrical member 53. The clock mechanism 84 is preferably an electrically operated clock mechanism mounted in' the housing 85 carried by the upper wall 44 of the housing 42 and :an opening 86 is provided in the central portion of Ithe wall 44 through which the shaft 51 projects.

A vertically disposed circuit closing bar 81 is secured as by fastening members 88 to the outer side of the cylindrical member or drum 53 and is adapt-ed upon rotation of the drum 53 to contact with a key or pin 49 in a selected :opening 45. An extension 69 is connected `at one end to one end of lthe wiper or circuit closing bar 61 and the opposite end of the extension 89 is provided with a downturned portion 18 secured las by fastening means 1| to the lower shaft 55. The bearing 58 for the shaft 55 is provided with an extension 12 and a terminal 13 is connected to rthe extension 12 so that a wire connected to the terminal 12 will close a circuit as will be hereinafter described upon engagement of the wiper or movable contact bar 81 with a selected key 49.

A cylindrical upwardly extending and transparent member 14 having a bottom wall 15 is mounted on the upper Wall 54 of the drum 53-54 and the bottom wall 15 is interposed between the upper wall 54 and the upper nut 6| so that the cup-shaped member formed by the wall 14 and the bottom 15 will rotate with the circuit closing drum 53-54. The periphery of the cylindrical part 14 is provided with graduations and time indicating means and a pilot light 18 mounted in a socket 11 carried by the bracket 18 is supported interiorly of the cylindrical member 14. The outer wall 42 of the housing 4| is provided with a window 19 through which the graduations on the drum 14-15 are visible. The graduations on the drum 14-15 are co-ordinated with the clock 85 so that when a selected key 49 is mounted in a selected opening 45 a circuit will be closed at a selected time. The bracket 18 is secured by a fastening means 88 to the housing 4| and in the present instance, is secured to the cylindrical wall 42.

An insulated base member 8| is mounted on the base 43 Within the housing 4| and a pair of L- shaped brackets 82 are secured as by fastening means 83 to the base member 8|. A rock shaft 84 is rockably mounted in the upstanding legs 85 of the L-shaped members 82 and a bar or lever 85 is secured to the rock shaft 84. The base 8| has secured to one side thereof a spring contact clip 81 and the lever or bar 85 has movably mounted thereon a circuit closing pin 83. The circuit closing pin 88 is slidable through the lever or bar 88 and is provided with a shoulder 89 limiting the movement in an upward direction of the pin 8B relative to the bar 8B. A spring 98 is disposed about the pin 88 above the lever 86 and at one end engages against the lever 85 and at the other end engages against a shoulder or collar 9| carried by the pin 88 at its upper end so as to constantly maintain the shoulder 89 in engagement with the under side of the lever 88.

A solenoid coil 92 is supported by a bracket 93 secured as by fastening means 94 to the base 8| and a movable core 95 having a lower head 96 is movable interiorly of the coil 92. The head 96 is connected to the rock lever 86 by means of a pivoted link 91 so that vertical movement of the core 96 will rock the lever 86 so as to thereby move the pin or circuit closing member 88 relative to the clip 81.

A second clip 98 similar to the clip 81 is secured to the base 8| on the opposite side of the rock shaft and the second circuit closing pin or member 99 is slidably mounted in the opposite end of the rock lever 86. The pin 99 has a shoulder |00 below the lever 86 so as to limit the upward movement of the pin 99 relative to the lever 86. A spring |0| is disposed about the pin 99 on the upper side of the lever 86 and the upper end of the spring engages a shoulder 92 carried by the pin 99 at its upper end and the lower end of the spring |0| engages the upper side of the lever 86. The pin 99 is adapted to be connected to one side of an electric circuit as will be hereinafter described.

A liquid switch |09 is mounted in a clip or holder ||0 carried by the rock shaft 84 and extends transversely of the rock shaft 84, This liquid switch |09 is adapted to be interposed in an electric circuit which is opened and closed by rocking of the shaft 84 and the lever 86 under the action of the movable core members 95 and |06. In this manner movement of the lever 86 in one direc tion will operate to break an electric circuit through the liquid switch |09 and movement of the rock lever 86 in the oposite direction will act to close the electric circuit associated with the switch |09. The lever 86 is provided on its under side with a depending member |21 and a yieldable lever holding member |28 is secured to the base 8| and is engaged with the depending member |21 so as to yieldably hold the lever 86 in a selected position determined by operation of one of the solenoid coils 92 or |03.

A circuit breaking relay generally designated is mounted on a base ||2 secured to the base 43 within the housing 4|. This circuit breaking relay comprises a pair of stationary contacts ||3 and ||4 as having terminals ||5 and ||6 respectively. These contacts ||3 and ||4 are disposed in spaced apart relation and are adapted to be connected to electric circuits to be hereinafter described. A solenoid coil ||1 is supported by a bracket or supporting member ||8 of substantially U-shape which is secured to the base ||2. A movable core ||9 is movable within the coil ||1 and the core ||9 has a head |20 at its lower end. A contact bridging member |2| is adapted, when in operative position, to bridge the two contacts 3 and ||4 and is provided with a central opening |22 through which a bar |23 slidably engages. The bar |23 at its lower end is provided with a head |24 and the upper end of the bar |23 is secured as at |25 to the head |20. A spring |26 is disposed about the bar |23 and the upper end of the spring |26 engages against the head |20 and the lower end of the spring |26 engages against the bridging member |2|.

A transformer |29 is mounted on the base 43 within the housing 4| and the primary of the transformer |29 is adapted to be connected to a source of electric current supply. The secondary of the transformer 29 is adapted to be connected to the solenoids hereinbefore described.

'I'he transformer |29 has the primary coil thereof connected as by conductors |30 and |3| to a source of electric current supply. The clock mechanism 64 is connected as by conductors |32 and |33 to the conductors |30 and |3| respectively. A pilot light |34 is interposed in the conductors |32 and |33.

The liquid switch |09 has one side thereof connected as by a conductor |35 to the conductor |3| and the other side is connected as by a conductor |36 to one side of the radio apparatus I5. The other side of the radio apparatus I5 is connected by a conductor |31 to the conductor |30. The secondary |38 of the transformer |29 has a conductor |39 connected to one side thereof and a conductor |40 connected to the other side thereof. The conductor |39 is connected to one side of each of the solenoid coils 92, |03, and ||1 as shown in Figure 4. The conductor |40 is connectedto the terminal 13 which is electrically connected to the wiper or circuit closing bar 6T. A conductor |4| is connected to the upper ring 46 carried by the drum 53 and is also connected to the terminal H5. The opposite side of the circuit breaking relay is connected as by a conductor |42 to the conductor |4|. The contact ||4 is connected to the yieldable contact or clip 81 by a conductor |43 and this conductor |43 is also connected to the yieldable clip or contact 98. One side of the solenoid coil 33 of the button operating member is connected as by a conductor |44 to a ring 46a and the other side of the solenoid coil 33 is connected as by a conductor |45 to the conductors |39 on one side of the secondary coil |38.

abl

The band |65 is maintained in the desired spaced relation to the underside of the metal strips |62 by means of an arcuate or arched guide member |11 which is secured as by supporting brackets |18 to the side walls |58 of the housing |56. The housing |56 is provided on the interior thereof with a relay |18a which is similar to the relay embodied in Figure 2 comprising the solwenoids 92 and |03 and the operating parts associated therewith. A circuit breaking relay or switch member |19 is also mounted in the housing |56 and is similar to the circuit breaking relay I I and a voltage reducing transformer similar to the transformer |29 is mounted in the housing |56. The electrical connections between the relays |189, |19 and the transformer |90 are similar in every detail to the diagrammatic connections shown in Figure 4.

In the use and operation of this radio apparatus tuning means the tuning operator I1 is adapted to be secured in any suitable manner to the iront face of the radio receiving apparatus I5 so that the tuning members I6 will project through the opening 20 into the interior of the housing supporting the operators. A key member 49 is inserted in a selected opening 45 and snugly held by means of the clips 48 for wiping engagement with the circuit closing bar 61. The key member 49 shown in contact with the bar 61 will close the lower voltage circuit from the secondary of the transformer |29 through the conductor |40, conductor I4I, bridg ingmember I2I, conductor |43 and conductor |39. Upon closing of th-e circuit to the secondary |38 of the transformer |29, the electric current will fiow through the solenoid coil |I1, through the conductor |42 and at this time, the core II9 Awill be raised, moving the switch operating bar |23 upwardly. In view of the fact that the head |24 of the bar |23 is spaced downwardly from the bridging member |2|, there will be a delay in the breaking of the circuit between the two contacts II4 and H5. This delay in the brea1 ing of the circuit between the conductor I4I and the conductor |43 will permit the electric current to flow to the solenoid |03. When the solenoid |03 is energized the core |06 will be drawn upwardly so as to disconnect the blade or pin 99 from the terminal or clip 98. The sliding connection between vthe pin 99 and the bar 86 will also permit a slight -delay in the breaking of the electric circuit to the solenoid |03, the bar 86 moving upwardly with the movement of the core |06 and compressing the spring IOI.

The circuit breaking member II I is provided so as to prevent continued rocking of the lever 86 and alternate opening and closing of the switch |99 which would result by closing of the electric circuit to the coil |93 which raises one end of the lever 36 until the lever 66 breaks the circuit to the coil |03. At this time the switch |99 is closed and the opposite end of the lever 86 has closed a circuit through the clip 81 and pin 90 to the coil 92. At this time also the circuit breaker I I I has broken the circuit from the wire |4| to the wire |43 and this circuit will remain broken so long as current ows from wires I4I and |42 to th-e coil ||1 and the wire |39, so that even though the coil 92 is connected through the switch comprising the pin and the clip 91 and coil 92 is not energized because the switch comprising the terminals I|4 and II5 and bridging member I2I is open.

Rocking of the bar 86 under the upward movement of the core |96 will cause the liquid switch |99 to be rocked to a circuit closing position, closing the electric circuit from the primary |53 of the transformer |29 through the conductors |35 and |36 and the conductor |31 to the radio apparatus. Closing of the liquid switch |99 will effect a closing of the main operating circuit to the radio apparatus I5 so as to energize the radio apparatus.

At the same time that the circuit closing bar 61 engages the key 49, the bar 61 will engage a selected key 49a. which closes a circuit through the conductor |44 and the conductor |45 to .the solenoid 33. When the solenoid 33 is energized, the core 34 will be drawn upwardly and movement of this core 34 upwardly will effect forward movement of the plunger 24. The head 26 of the plunger 24 will then engage the tuning member I6 and effect movement `thereof so as to thereby tune a selected .broadcast band in the radio apparatus I5. The forward movement of the plunger 24 is cushioned by the spring 32.

A tuning device constructed according to this invention may be partly connected directly to the radio apparatus and another part disposed remote from and connected to the rst part for controlling operation of the radio apparatusunder a time controlled means. It will, of course, be understood that if desired the time controlled means may be directly incorporated in the radio cabinet or apparatus, but primarily the device is constructed as an attachment for connection to the present structure of radio apparatus provided with selective station tuning devices. The time controlled tuning means hereinabove described may be `either cut on or on by operation of the manually operable switch |46 which is connected to the transformer |29 and also to the liquid switch |09. If it is desired to manually control the radio apparatus the switch |46 will be positioned as shown in full lines in Figure 4.

However, if it is not desired to control the radio apparatus by the hereinb'efore described time controlling means, the switch |46 is moved to the dotted line position shown in Figure 4 wherein the blade |52 bridges the two terminals |41 and I5! and the blade |54 bridges the terminals |59 and I5I.

vThe radio receiving apparatus I may be cut oir at a predetermined time by inserting a second key 49 in a succeeding opening 45 so that when the clock mechanism 65 rotates the drum 53,4the bar 61 will contact the second k-ey 4t and thus close the circuit through the conductors |39, |40, |4| and |43 to the solenoid coils Ill, 92 and |03. While the radio apparatus is in operation the switch |09 is closed and the pin 9D is in contact with the terminal 81. Upon closing of the circuit by the succeeding pin di, the solenoid coil 92 will be energized so as to move the pin 9) to a released position, thus moving the bar 86 to a position whereby the switch |09 will be in a circuit breaking position. In this manner the radio apparatus l5 may be cut off at any predetermined time and if it is desired to turn the radio apparatus on again at a succeeding time, an additional pin or key 49 may be inserted in a further succeeding opening or socket 45.

What I claim is:

1. An attachment for a radio receiving apparatus having selective tuning members, an electro-magnetic operating member for each tuning member, circuit closing means for said operating member, a switch connected to the supply source for the radio apparatus and connected to the radio apparatus, a switch operating circuit, an electro-magnetic operator connected to said switch for moving said switch to a circuit closing position, a second electro-magnetic operator connected to said switch for moving said switch to a circuit breaking position, a single electric circuit for said electro-magnetic operators, a circuit making and breaking means in said latter circuit and connected to said operators for operation thereby, said circuit making and breaking means including means whereby energization of one of said operators will break the electric circuit thereto, and simultaneously close the circuit to the other operator, a relay in said single circuit for breaking said circuit upon energization of one of said operators, and means for energizing said rst electro-magnetic operating member.

2. An attachment for a radio receiving apparatus having selective tuning members, an electro-magnetic operating member for each tuning member, circuit closing means for said operating member, a switch connected to the supply source for the radio apparatus and connected to the radio apparatus, a switch operating circuit, an electro-magnetic operator connected to said switch for moving said switch to a circuit closing position, a second electro-magnetic operator connected to said switch for moving said switch to a circuit breaking position, a single electric circuit for said electro-magnetic operators, a circuit making and breaking means in said latter circuit and connected to said operators for operation thereby, said circuit makingand breaking means including means whereby energization of one of said operators will break the electric circuit thereto, and simultaneously close the circuit to the other operator, said circuit making and breaking means also including means whereby the breaking of the electric circuit to an operator is delayed until an operator has substantially completed a cycle in its operation, a relay in said single circuit for breaking said circuit upon energization of one of said operators, and means for energizing said rst electromagnetic operating member.

3. An attachment for a radio receiving apparatus having selective tuning members, an electro-magnetic operating member for each tuning member, circuit closing means icr said operating member, a switch connected to the supply source for the radio apparatus and connected to the radio apparatus, a switch operating circuit, an electro-magnetic operator connected to said switch for moving said switch to a circuit closing position, a second electro-magnetic operator connected to said switch for moving said switch to a circuit breaking position, a single electric circuit for said electro-magnetic operators, a circuit making and breaking means in said latter circuit and connected to said operators for operation thereby, said circuit making and breaking means including means whereby energization of one of said operators will break the electric circuit thereto, and simultaneously close the circuit, to the other operator, said circuit making and breaking means also including means whereby the breaking of the electric circuit to an operator is delayed until an operator has substantially completed a cycle in its operation, a relay in said single circuit for breaking said circuit upon energization of one of said operators, said relay including means for holding said single circuit closed for a period of time sucient to permit an operator to complete a cycle of its operation, and means for energizing said rst electro-magnetic operating member.

4. An attachment for a radio receiving apparatus having selective tuning members, an electro-magnetic operating member for each tuning member, circuit closing means for said operating member, a switch connected to the supply source for the radio apparatus and connected to the radio apparatus, a switch operating circuit, an electro-magnetic operator connected to said switch for moving` said switch to a circuit closing position, a second electro-magnetic operator connected to said switch for moving said switch to a circuit breaking position, a single electric circuit for said electric-magnetic operators, a circuit making and breaking means in said latter circuit and connected to said operators for operation thereby, said circuit making and breaking means including means whereby energization of one of said operators will break the electric circuit thereto, and simultaneously close the circuit to the other operator, said circuit making and breaking means also including a pair of loosely coupled members operable to delay the breaking of the circuit to an operator until the operator has substantially completed a cycle in its operation, a relay in said single circuit for breaking said circuit upon energization of one of said operators, and means for energizing said rst electro-magnetic operating member.

5. An attachment. for a radio receiving apparatus having selective tuning members, an electro-magnetic operating member for each tuning member, circuit closing means for said operating member, a switch connected to the supply source for the radio apparatus and connected to the radio apparatus, a switch operating circuit, an electro-magnetic operator connected to said switch for moving said switch to a circuit closing position, a second electro-magnetic operator connected to said switch for moving said switch to a circuit breaking position, a single electric circuit for said electric-magnetic operators, a circuit making and breaking means in said latter circuit and connected to said operators for operation thereby, said circuit making and breaking said circuit upon energization of one of said operators, said relay including a pair of loosely coupled members for holding said single circuit closed for a period of time to permit an operator to complete a cycle of its operation, and means for energizing said rst electromagnetic operating member.

WILLIAM H. MURRAY.