US2286283A

US2286283A - Multiplying operating mechanism for permeability tuning purposes

Info

Publication number: US2286283A
Application number: US257312A
Authority: US
Inventors: Martin J Kirk; Frederick N Jacob
Original assignee: Johnson Laboratories Inc
Current assignee: Johnson Laboratories Inc
Priority date: 1939-02-20
Filing date: 1939-02-20
Publication date: 1942-06-16
Anticipated expiration: 1959-06-16

Description

June 1 6, 1942. M. J. KIRK ETAL 2,286,283

MULTIPLYING OPERATING MECHANISM FOR PERMEABIL-ITY TUNING PURPOSES Filed Feb. 20, 1939 INVENTORS MflET/IYJ k/EK FREDERICK/V J4 c015.

MMEM

ATTORNEY.

Patented June 16, 1942 MULTIPLYING OPERATING MECHANISM FOR. PERMEABILITY TUNING PURPOSES Martin J. Kirk and Frederick N. Jacob, Chicago, Ill., assignors to Johnson Laboratories, Inc., Chicago, 111., a corporation of Illinois Application February 20, 1939, Serial No. 257,312

'6 Claims.

Our invention relates to mechanism for operating the movable elements of inductors havin variable permeability, to change the inductance of said devices for desired purposes, for example for effecting the tuning of resonant circuits of which said inductors may be parts. Our invention is applicable particularly to inductors provided with cylindrical ferromagnetic cores, in which permeability variation is effected by giving different positions to the cores relatively to the coils with whichthey are used, either by moving the cores, the coils, or both.

With inductors of the kind referred to, particularly where the inductance variation is desired to tune resonant circuits over a band such as the broadcast band, it is found in practice desirable to impart a considerable amount of movement to the movable elements of the inductors, which movable elements are generally for convenience taken as the cores of the inductors rather than the coils, since it is found in practice that more satisfactory results are S e y using co ls of relatively small diam- .eter and substantial length, and cores of the same proportions rather than coils and cores of large diameter and short length. With inductors of the particular type last referred to, it is important that the operating mechanism shall impart a straight line movement to the cores,

to effectively operate them and avoid friction in the operating mechanism. At the same time, it is desirable to provide the operating mechanism with parts having rotary movement to facilitateconnection with operating knobs and to facilitate the use of indicating scales of one kind or another, the operating knobs being preferably related to the rest of the operating mechanism so that they have considerably more movement than other parts of the operating mechanism and also than the cores, so that the adjustment of the cores may be effected with any degree of precision desired.

By our invention we provide improved mechanism for transforming the rotary motion of the operating mechanism into rectilinear motion so that the ferromagnetic cores of the inductors may be operated in substantially an ideal manner.

Our invention will be best understood by reference to the accompanying drawing illustrating a preferred embodiment thereof, in which:

Fig. 1 shows our operating mechanism in front elevation;

Fig. 2 shows our operating mechanism and variable inductors operated thereby in rear elevation;

Fig. 3 is a vertical, sectional view of the structure shown in Figs. 1 and 2, taken along the line 3-3 in Fit. 2, and

Fig. 4 is a fragmentary view illustrating a modified form of link mechanism between the operating shaft and the core carrying member of the operating mechanism.

Similar numerals refer to throughout'the several views.

As shown in Fig. 1, our operating mechanism is provided with a mounting plate ll supporting a shaft II for rotary movement, a drum I! being rigidly secured to said shaft in front of said plate. A rotary spindle I3 is also mounted in the plate It and extends forwardly therefrom for connection with the drum I! by a cable J4 to drive said drum by rotation of said spindle. As shown in Fig. 3, the spindle II is provided with an operating knob It for operation by the operator of the device. The diameter of the spindle I3 is very much less than the diameter of the drum l2, and in that way the amount of rotation of the spindle I3 is much greater than the amount of rotation of the shaft H, which facilitates accurate operation of said shaft. As shown in Figs. 1 and 3, the cable I] is continued from the upper portion of the drum in opposite irections horizontally around grooved sheaves I6 and H, from which said cables return to a pointer l8 mounted for sliding horizontal engagement on the upper edge of a plate l9 supported by the mounting plate ID in front of the upper part of the drum l2, to carry an similar parts indicating scale 20. The movement of the pointer I8 relative to the scale 20 is thus proportional to the angular movement of the shaft ll.

As shown in Fig. 2, the shaft H has secured to its back end a crank 2|, the outer end of which crank is pivotally connected at 22 with the mid-portion of a lever 23, the upper end of which is provided with a roller 14 held in rolling engagement with a fence 25 by a spring 26, said fence being formed fromthe mounting plate II and being horizontally disposed, assuming that as shown in Fig. 2, vertical movementis to be imparted to the ferromagnetic cores employed. The other end of the lever 23 is pivotally connected at 21 with a yoke 28 rigidly secured at its mid-portion to a bar 29 mounted for sliding engagement in a flange ll formed from the mounting plate l0, so that said bar may slidefreely through said flange in a vertical direction.

The lower edge of the mounting plate |8 is provided with a flange 3| supporting the lower ends of insulating tubes 32 on which inductance coils 33 are wound, the upper ends of said tubes being supported by'a plate 34 of insulating material carried by flanges 35 formed from the mounting plate I 8. The tubes 32 contain with a sliding fit ferromagnetic cores 38 from the upper ends of which slender threaded rods 31 extend for connection with the yoke 28. The rods 31 carry thin-walled insulating sleeves 38 adjacent the yoke-28, which sleeves are preferably of material much softer than the rods 31, for example, fibre, and at first loosely fit the rods 31; said sleeves are pressed firmly against the yoke 28 by clip plates 39 secured to yoke 28 in any suitable mannenforexample by rivets 48, said clip plates being resilient so as t exert yielding pressure on the sleeves 38 sufficient to press the sleeves more or less into the threads on the slender rods 31, to prevent accidental turning of said rods in said sleeves, as well as to hold said sleeves in fixed position on the yoke 28. This provides a construction which insulates the cores 36 from the yoke 28 and at the same time permits adjustment of the cores relatively to the yoke by turning the rods 31, for any desired purposes, such as aligning and tracking the cores.

We find it desirable to restrict the movement of the crank 2| to substantially 90 by stops 4| and 42 formed from the mounting plate In in such a manner that the movement of the crank 2| is substantially 45 above and 45 below a horizontal line through the center of the shaft II, for the direction of movement of the cores 36 illustrated in Fig. 2. The effective length of the crank 2| is made equal to the center-tocenter dimension between the pivotal connection 22 and the roller 24, as well as equal to the center-to-center dimension between the pivotal connection 22 and the pivotal connection 21, the centers of the pivotal connections 22, 21 and the center of the roller 24 being in substantially a straight line. The diameter of the roller 24 is so taken that the center of the roller is maintained by the fence 25 and the spring 28, in a horizontal line extendingthrough 'the axis of theshaft With the relation of parts described, angular movement of the crank 2| between the stops 4| and 42 will move the center of the pivotal connection 21 in a vertical line extending through the axis of the shaft H, and as a result, operation of said crank moves the yoke 28 vertically, and thus imparts no lateral movement to the rods 31 and the cores 36.

The lever 23 is provided with a spring 43 en- The coils 33 may be enclosed by a shield 48 if desired, which shield is removed in Fig. 2 to more clearly show the parts contained therein.

In Fig. 4 we illustrate a modified form of the connecting device of our operating mechanism, in which the lever 23 is pivotally connected at its upper end at 43 with a link 58, extending vertically and pivotally supported at its upper end at 5| from the mounting plate l8, the'rest of the construction being the same as above described in connection with Fig. 2. In this case, a spring 52 engages the pivotal connections 49 and 5| to take up the lost motion of said connections.

With this construction, the accuracy of movement of the pivotalconnection 21 at the lower end of the lever 23, in a vertical line through the axis of the shaft II, is determined by the length of the link 58, the departure of the piv otal connection 21 from said vertical line of movement being inappreciable where the crank 2| is restricted to the mid-portion of its movement and the link 58 is of substantial length.

It is to be noted, that if desired inany'case, the angle of movement of the crank 2| may be made greater than 90, or said movement may be unequally distributed relatively to a horizontal line through the axis of the shaft or both, without departure of the pivotal connection 21 from straight line vertical movement, if the roller and fence construction, 24, 25, of Fig. 2 is employed, for which greater angle of operation, however, there may be a slight departure of the pivotal connection 21 from vertical straight line movement if the link connection 58 of Fig. 4 is used, the amount of said departure being determined by the length of the link 58.

While we have shown our invention in the particular embodiment above described, it will be understood that ,we do, not limit ourselves thereto as we may employ equivalents thereof without departing from the scope of the appended claims.

Having thus described our invention what we claim is:

1. An operating mechanism for the movable element of a variable inductance device having straight-line movement, consisting of a rotary shaft, a crank carried by said shaft, a lever pivotally connected at its mid-portion with and gaging the pivotal connection 22 to take up any a lost motion there may be in said connection, and the yoke 28 carries a spring 44 engaging the pivotal connection 21 to take up any lost motion there may be in that pivotal connection. The lower end of the bar 29 is connected with a side wall of the mounting plate l8 by a spring 45 which eliminates lost motion between the bar 28 and the guiding flange 38.. As shown in Figs. 1 and 3, the mounting plate l8 may be provided on its front wall with capacitors 48 .and 41 of the trimmer type, which may be concarried by said crank, said crank having movement in opposite directions from a position in alignment with said lever, and means restraining movement of one end portion of said lever substantially to the center line of said alignment, whereby movement of the other end portion of said lever is limited to substantially straight-line movement perpendicular to said center line of alignment and said other end portion of said lever may be mounted for movement inthe line of movement of the movable element of the in- ,ductance device for operative connection with said movable element.

2. An operating mechanism for the movable element of a variable inductance device having straight-line movement, consisting of a rotary shaft, a crank carried by said shaft, a lever pivotally connected at its mid-portion with and carried by said crank, said crank having movement in opposite directions from a position in alignment with said lever, and means restrain- 1 ing movement of one end portion of said lever pacity in operation after they are so aligned.

substantially to the center line of said alignment, whereby movement of the other end portion of said lever is limited to substantially straight-line movement perpendicular to said 'tion of said lever may be mounted for movement in the line of movement of the movable element of the inductance device for operative connection with said movable element, said restraining means including a member having a plane surface extending in the direction of said center line of alignment and in engagement with the restrained lever end held against and movable along said plane surface towards and from said shaft.

3. An operating mechanism for the movable element of a variable inductance device having straight-line movement, consisting of a rotary shaft, a crank carried by said shaft, a lever pivotally connected at its mid-portion with and carried by said crank, said crank having movement in opposite directions from a position in alignment with said lever, and means restraining movement of one end portion of said lever substantially to the center line of said alignment, whereby movement of the other end portion of said lever is limited to substantially straight-line movement perpendicular to said center line of alignment and said other end portion of said lever may be mounted for movement in theline of movement of the movable element of the inductance device for operative connection with said movable element, said restraining means including a member having a plane surface extending in the direction of said center line of alignment, a roller carried by the restrained end of said lever, and means holding said roller in engagement with said plane surface.

4. An operating mechanism for the movable element of a variable inductance device having straight-line movement, consisting of a rotary shaft, a crank carried by said shaft, a lever pivotally connected at its mid-portion with and 'carried by said crank, said crank having movement in opposite directions from a position in alignment with said lever, and means restraining movement of one end portionof said lever substantially to the center line of said alignment,-

whereby movement of the other end portion of said lever is limited to substantially straight-line movement perpendicular to said center line of alignment and said other end portion of said lever may be mounted for movement in the line of movement of the movable element of the inductance device for operative connection with said movable element, said restraining means in-' cluding a membenhaving a plane surface extending in the direction of said center line of alignment, a roller carried by the restrained end of said lever, and spring means holding said roller in engagement with said plane surface.

5. An operating mechanism for the movable element of a variable inductance device having straight-line movement, consisting of a rotary shaft, a crank carried by said shaft, a lever pivotally connected at its mid-portionwith and carried by said crank, said crank having movement in opposite directions from a position in alignment with said lever, and means restraining movement of one end portion of said lever substantially to the center line of said alignment, whereby movement of the other end portion of said lever is limited to substantially straight-line movement perpendicular to said center line of alignment and said other end portion of said lever may be mounted for movement in the line of movement of the movable element of the inductance device for operative connection with said movable element, said restraining means including a link pivotally connected at one end with said restrained end portion of said lever and extending in a direction substantially perpendicular to said center line of alignment, said link being pivotally connected at its other end to a stationary support.

6. A permeability tuning operating mechanism for converting rotary motion into substantially rectilinear motion, including a rotary driving member, a driven member having reciprocating movement, a lever attached at one of its ends to said driven member and at its mid-portion directly connected with said driving member, and a bar pivotally connected at one of its ends with the other end of said lever, the other end of said bar having pivotal connection with a fixed support and restraining motion of said other end of said lever to arcuate movement determined by said bar whereby motion of said first-mentioned end of said lever is restrained to a substantially straight line extending perpendicularly to the line of movement of said other end of said lever.

MARTIN J. KIRKi FREDERICK N. JACOB.