US2036999A - Wireless receiving apparatus - Google Patents

Description

2&36399 April 1 R s. BUNTING WIRELESS RECEIVING APPARATUS Filed. March 50, 1955 3 Sheets-Sheet l g m m m M 0 MW m w z 7 M fl// mm \ww April 14-, W36 R. s. BUNTXNG I WIRELESS RECEIVING APPARATUS Filed March 50, 1953 I5 Sheets-Sheet 2 April 4, 1936, R. s, BUNTING WIRELESS RECEIVING APPARATUS I5 Sheets-Sheet 5 Filed. March 50, 1933 Eh W II ATTOF/Vfy Patented Apr. 14, 1936 UNITED STATES PATENT OFFICE signor to The British ited, London, England Application March 30, 1933,

Radio Corporation Lim- Serial No. 663,602

In Great Britain April 4, 1932 Claims.

In the specification a wireless receiver is described which comprises a series of inductances corresponding in number to the tuned input or intervalve circuits on the high frequency side of 5 the receiver, hereinafter referred to generally as input circuits and separate assemblages of fixed or semi-fixed condensers arranged in definite banks or groups, the number of such banks or groups corresponding to the number of different stations to which the receiver can be tuned, while the number of condensers in each group corresponds to the number of tuned stages and switching mechanism whereby each of the said inductances is simultaneously combined with one or other of said condensers to form a predetermined chain or sequence of similarly tuned circuits.

According to this invention, a step by step adjustable control member is provided, having a multiplicity of rotary setting positions in one range of movement, in which it switches in fixed tuning condenser elements having predetermined capacities to tune the input circuit or circuits to selected predetermined Wave lengths, and another range of movement during which it controls the volume of the output of the apparatus without affecting the tuning.

Inductance and condenser elements are connected to form a plurality of partially completed circuits tuned to predetermined fixed wave lengths with a selector switch for completing any of said circuits through the aerial and detecting system of the apparatus, an operating member for moving this selector switch in one direction only, and a variable resistance controlling the valve filament current, rotation of the operating member in one direction operating the selector switch, and rotation thereof in the opposite direction operating the variable resistance without operating the selector switch.

The apparatus comprises a condenser, or a series of condensers corresponding to the plurality of circuits to be tuned, such condensers or each condenser comprising two sets of fixed plates, one set being all permanently connected to the input circuit to be tuned and the other set being insulated into connected groups of varying surface areas, the rotary selector switch being adapted toconnect any one of said groups, or a plurality of selected units of said groups in parallel, into the input circuit to be tuned, by a step by step rotary movement of the switch in the same direction, movement of said switch in the reverse direction controlling the output volume of the apparatus without affecting the tuning.

Each inductance may comprise a pair of coils arranged in sequence, one of the coils of each pair being adapted for short-wave reception by short circuiting the other coil by the operation of the switch mechanism.

The input circuit or circuits is or are tuned to 5 the wave-length of the selected station by rotation of the single controlling knob in one direction, rotation of the knob in the reverse direction, controlling the volume of the signals as required.

The single controlling knob may also control the on and off switch to the source of electrical supply to the apparatus and a gramophone control switch.

The switching mechanism aforesaid comprises a number of spider frames mounted side by side on an operating spindle, the number of radial arms or vanes of each spider depending upon the number of stations to which the receiver can be tuned; the arms of each spider are staggered relatively to each other and each arm carries a contact member on its outer end adapted when the spiders are rotated to make contact with contacts connected to the condenser plates, there being one of such contacts to each single fixed plate and each combination of two or more fixed plates.

The invention will be best understood from the following description taken in conjunction with the accompanying drawings including Figures 1-8 which show a wireless receiver tuning ap paratus having an input circuit and two intervalve circuits on the high frequency side of the receiver.

In the drawings- Figure 1 is the plan view of the tuning mechanism constructed according to the present invention and adapted for the aerial and two intervalve circuits;

Figures 2, 3, and 4 are sectional views looking in the direction of the arrows respectively associated with the lines A-A, B-B, and CC of Figure 1.

Figure 5 is an end view looking in the direction of the arrow D, of Figure 1.

Figure 6 shows the panel indicating arrangements.

Figure 7 shows an arrangement by which a second receiver such as a television signal receiving apparatus using a similar condenser arrangement to that shown in Figure 1 may also be controlled by the single controlling knob, and

Figure 8 shows the circuit arrangements of the tuning apparatus of Figure 1.

Referring more particularly to Figure 1 it will be seen that in the example shown there are three similar sets of stationary condensers I, 2, 3 and a fourth set 4 all supported by, but insulated from the frame 5 in the usual manner.

In each similar set of condensers l, 2, 3, one set of alternate plates are connected together whilst the other set of alternate plates is divided into groups consisting of one, two or more plates according to the capacity desired, the plates of each group being connected together so as to give a determined capacity value and each group being connected to a respective contacting brush 6 supported by, but insulated from the support I. The number of similar sets of condensers corresponds with the number of input circuits to be simultaneously tuned. Each set of condensers is screened ofi by the partitions ll.

With each contacting brush 6 is associated a metal spider 8, having two more radial arms 9, than the number of wave lengths to which the apparatus is to be tuned. In the present example there are fourteen arms 9, capable of tuning to l2 difierent wave lengths. The spiders 8 are arranged parallel to each other and are mounted on and in electrical connection with a spindle Iii, which is supported in suitable bearings 12, I3. It will be noticed that the spindle It does not pass through the control panel 2!].

The radial arms 9 of each spider 8 are staggered so that according to the angle of rotation of the spindle Iii from its inoperative position only certain predetermined arms make contact with the brushes 6 thus only throwing into circuit a predetermined capacity value. The corresponding arms of two or more spiders of each set may be used at one time to give the desired capacity, thus throwing in parallel two or more groups of plates.

Each spider arm 9 is provided near its end with a contact M which contacts with a brush 6; there being four different sets of condensers there are four corresponding sets of spiders, three sets being similar and the fourth set associated with the condenser set 4 which will be referred to later. One spider 8a of each similar set, is insulated from the spindle l0, and contacts with a brush 6a in predetermined positions for a purpose hereinafter described.

The end of the spindle IE adjacent to the control panel is provided with one or-more toothed wheels IE, it around each of which a chain passes to drive another controlling spindle or switching mechanism as shown in Figure '7 and which will be referred to later. The outermost wheel [6 (see also Figure 2) is provided with a pin 11, projecting parallel with the axis of the wheel.

The controlling knob i8 is mounted on a spindle ii! which is supported in the panel 23 in the usual way, and carries on its other end a sleeve 21 which is rigidly fixed to the spindle l9 and carries a projecting radial pin 22. The contacting brush 23 which contacts with the resistance coil 25 is carried on a collar 23a l-oosely mounted on the spindle 9, a friction washer Zia being interposed between the sleeve .H and the collar 23a, the outer face of which bears against a spring washer. Thus by rotation of the knob 18 the brush 23 can be caused to travel in either direction with respect to the coil 24.

The pin 22 contacts with the pin I1 and as the controlling knob I8 is turned in one direction (clockwise) the pin 22 pushes the pin H forward thus causing the spindle ID with its spiders 8 to rotate.

At the other extremity, the spindle I0 is provided with a pawl and ratchet mechanism 25 (see Figure 5) which allows the spindle ID to rotate in one direction (anti-clockwise) (in Figure 5) only.

The tension of the pawl-controlling spring 25a is so adjusted and the teeth of the ratchet wheel so shaped that the frictional resistance is greater than the frictional resistance between the friction washer 2 la and the collar 23a. Thus the spindle I0 is held stationary when by rotation of the knob iii the brush 23 is operated for volume control.

The spiders associated with the condenser set 4 are two in number which are insulated from the spindle l0 and from one another. One set of plates of the condenser 4, the aerial condenser, are divided into two groups so as to give two difinite capacity values. One group of plates is connected to a brush 4a and the other group of plates is connected to a brush 41) (see Figure 1). The set connected to 4a give a small capacity and is used when greater selectivity is required or when tuning in to a powerful station. The set connected to 4b is of greater capacity quired is not so great, or when tuning in to a weaker station.

The spider arms 1c are so staggered that an armof only one of the sets is in contact with either of the brushes 4a or 41). A brush 4d is supported by, but insulated from, the frame 5 so as to bear on the arms or" both spiders and is connected to the aerial terminal 38 (see Figure 4). A Vernier condenser 3% is also provided and this is connected directly to the aerial circuit.

Figure 4 shows more clearly the device for switching on and off the electrical power supply to the apparatus when the tuner is brought into use. This comprises a pair of spring iuged contacts 25, 21 one of which 23 engages a cam disc 28 on the operating spindle [0, thereby making contact which is broken when a recess on the cam disc 28 comes, in the course of the rotation of the disc, opposite to the contacts and they are separated, as shown in Figure 4 thus opening the circuit of the electrical power supply to the apparatus. The recess in the disc 28 is arranged to come opposite the contacts in the off position of the operating spindle ii). A similar device to that shown in Figure 4 may be adopted for use as a gramophone control switch, such as a notched disc which when the controlling knob I8 is set to gramophone position allows contact members to come together to complete the connections of the wireless receiver system with the electrical pick-up system of the gramophone. The panel indicating arrangements shown in Figures 6 and 7 consist of a plate 29 provided at intervals with slots framing transparent name plates bearing the wave lengths, names of transmitting stations or other indicia of the received signals. Behind this plate there is a rotating arm 30 mounted on a spindle 3| which, as shown in Figure '7 is provided with a driving wheel 32 which is driven by a small chain or belt from the main spindle Ill. The spindle 3| is supported in bearings on the bracket 33 fixed at the back of the loud speaker bafiie 29a. The free end of the arm 30 is provided with a lamp holder and indicating lamp 34. An insulated contact plate rotates in unison with the spindle 3| and the contacts of the plate are connected up to one of the lamp 34 terminals. When the lamp 34 is rotated behind the plate 29 the contact on the insulated contact plate completes a circuit to supply the;

and is used when the selectivity relamp with current, the return of the circuit being through the spindle 3|. Thus the lamp indicates to which wave length or transmitting station etc., the tuner is tuned by reflection through the particular transparent name plate.

.Figure 7 also shows how a television signal receiving set 35 may be tuned in unison with another signal receiving set by means of the belt or chain coupling 36 driven fromthe operating knob l8 and spindle l0.

- Referring to Figure 8, the coil S. W. alone is used for short wave lengths, the coil L. W. used only for long waves, being cut out .of action by a contacting brush 31, which is always in contact with spiders 8a, the arms of which in short wave positions contact with brush 6a thereby short circuiting the coil L. W. The arms of the spider 8a corresponding to long wave positions do not make contact with brush 6a so that the coil L. W. remains in circuit in series with coil S. W. Similar arrangements are provided for each high frequency stage as well as for the detector stage D.

It will be understood that the receiver is adjusted in the course of manufacture in such a manner that the contacts M on the staggered arms of the spider elements 8 of the switching mechanism contact with predetermined contact brushes 6 connected to the fixed condenser plates according to the capacity required to suit the wave lengths of the several stations to which the receiver can be tuned and also the arms of the spider element 811 are staggered in a predetermined manner to perform their operation when required.

When it is required to tune in the receiver to one of the stations indicated on the selector panel, the controlling knob is rotated, say in a clockwise direction, and the pin 22 pushes the pin l'l forward causing the spindle H] to rotate. Continued rotation of the spindle brings the indicator lamp 34 opposite the name plate of the station required.

The spider elements 8 also having been rotated with the spindle ID, a successive set of the arms or vanes 9 thereof are brought into contact with predetermined contact brushes 6 connected to the first condenser plates to suit the wave length of the station selected. The spiders 40 will also have been rotated so as to select the right capacity for the aerial condenser and if the station selected transmits on a short wave, the long wave inductance coils L. W. will be short circuited as already explained. In the example shown there are fourteen arms equally spaced on each spider element. One corresponds to the off position of the switch controlling knob when the main circuit is broken at 26, 21, all the spider arms being then out of contact with brushes 6 and 6a and another corresponds to the gramophone position of the controlling knob, when the wireless apparatus is connected to the gramophone pick-up unit, as already described, by a switch similar to the switch 26, 21, 28. Thus each spider has two arms which are, in fact, dummies. The remaining twelve positions are taken up with twelve stations of definite wave lengths.

When the station has been selected the controlling knob I8 is turned in the reverse (or anti-clockwise) direction causing the brush arm 23 to travel over and in contact with the resistance element 24, and thereby regulating the volume of the signals as required.

Arrangements may be made to increase the amount of coupling between the various tuned circuits by bringing in or cutting. out additional condensers which would be governed .by the switching mechanism and is obvious to those skilled in the art.

It is to be understood that the invention does not include within its scope any multiple variable condenser unit having movable condenser plates, or having fixed plates in combination with a plate selecting switch, unless the latter also has a range of rotary movement during which it controls the volume output of the apparatus without affecting its tuning.

What I claim is:-

1. Wireless receiving apparatus including a tuning apparatus for input circuits, condensers corresponding to a plurality of circuits to be tuned, such condensers comprising two sets of fixed plates, one set being all permanently connected to an input circuit to be tuned and the other set being insulated into connected groups of varying surface areas, in combination with arotary selector, a rotary volume control member, an operating member loosely engaging said selector and fixedly carrying said control member, said selector adapted to connect any one of said groups, or a plurality of selected units of said groups in parallel into the input circuit to be tuned, by a step by step rotary movement of the selector, means for effecting rotation of the selector by rotation of the operating member in one direction only, and means for efiecting rotation of the volume control member alone by rotation of the operating member in the opposite direction.

2. In a wireless receiving apparatus including a tuning apparatus for input circuits, condensers corresponding to a plurality of circuits to be tuned, said condensers comprising two sets of fixed plates, one of said sets being permanently connected to an input circuit to be tuned, the other set of plates being insulated into connected groups of varying surface areas, a rotary selector rotatable in one direction only adapted to connect a plurality of selected units in parallel with the input circuits to be tuned, a rotatable operating member loosely engaging said selector, a controlling member adapted to actuate said operating member to tune the input circuits with the wave length of the selected station when rotated in one direction, a volume regulating member on said controlling member, means for rotating said selector and control member with rotation of said controlling member in one direction, and means for rotating said volume member alone with rotation of said controlling member in the opposite direction.

3. In a wireless receiving apparatus having an aerial and detecting system, inductance and condenser elements connected to form a plurality of partially completed circuits tuned to predetermined fixed wave lengths, a selector switch for completing any of said circuits through the aerial and detecting system of the apparatus, a rotatable operating member, means engaging said switch and said member for moving said selector switch in one direction only, a variable resistance carried by said member and controlling the valve filament current, means engaging said resistance and said member upon rotation of the member in the opposite direction to effect adjustment of the variable resistance independently of the selector switch, said inductance means comprising a pair of coils arranged in sequence, and means controlled by said operating member for cutting out one of said coils through said switch mechanism.

4. Wireless receiving apparatus including a tuning apparatus for input circuits, condensers corresponding to a plurality of circuits to be tuned, such condensers comprising two sets of fixed plates, one set being all permanently connected to an input circuit to be tuned and the other set being insulated into connected groups of varying surface areas, in combination with a rotary selector adapted to connect any one of said groups, or a plurality of selected units of said groups in parallel into the input circuit to be tuned, by a step by step rotary movement of the selector, a volume control member, an operatlng member loosely engaging said selector and fixedly engaging said control member, means for rotating said selector and operating member in one direction, and means for rotating said operating member and said volume control member in the reverse direction independently of said selector.

5. Wireless receiving apparatus including a by step rotary movement of the member in the same direction, movement of said member in the reverse direction controlling the output volume of the apparatus without ailecting the tuning, and pawl and ratchet means for holding said spindle and selector from rotating relative to each other in one direction.

REGINALD STEWART BUNTING.

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