GB2183100A - Variable capacitor and variable resistor combinations - Google Patents

Abstract

A variable capacitor (1) is provided with a plurality of terminals (1a) and has a rotatable rotor shaft (1b). A switch (8) having its electrodes (1c and 1d) formed on the front base of the variable capacitor (1) has sliders (4a, 4b) fitted around the rotor shaft for contacting the electrodes (1c, 1d) to provide electric conduction therebetween. A variable resistor (9) is mounted on the terminals of the variable capacitor (1) and comprises sliders (3a, 3b) fitted around the rotor shaft for contacting with the resistor terminals to provide electric conduction therebetween. Thus, the rotor shaft (1b) acts as a common drive shaft for the variable resistor (9) and the switch (8) so that the capacitance of the variable capacitor (1) and the resistance of the variable resistor (9) may be varied and the switch (8) may be turned on or off as the rotor shaft (1b) is turned. <IMAGE>

Description

SPECIFICATION Variable condenser assemblies The present invention relates to variable condenser assemblies. In variable condenser assemblies a variable condenser is integrated with a variable resistor and with a control for varying the capacitance of the condenser and the resistance of the resistor and for turning the control on or off.

Audio products which use such variable condenser assemblies include radio receivers and cassette tape recorders with radio receivers. In recent years, these audio products are promoted for their size reduction and high integration and are increasingly desired to have multiple functions such as the reception of TV audio bands. In order for a variable resistor to be assembled integrally with a variable condenser and to effect the high integration and the multiple functions, there has already been produced the so-called "variable condenser assembly with a variable resistor", in which the variable resistor is mounted on a common rotor shaft forming with a variable condenser and the resistance of the variable resistor can be simultaneously varied by rotating the common shaft.

In the radio receiver or the cassette tape recorder with the radio receiver in which the so-called "variable condenser assembly with the variable resistor", generally speaking, the variable condenser is used for receiving the AM and FM bands of radio frequencies and the VHF bands of TV audio frequencies whereas the variable resistor is used for receiving the UHF bands of the TV audio frequencies.

In a TV set with a radio receiver, which is being produced in recent years, on the contrary, the variable condenser is caused to bear the receptions of the AM bands and the FM bands whereas the variable resistor is caused to bear the receptions of the VHF and UHF bands of the TV audio frequencies by the scale characteristics and the image processing after turning off the TV set. If the variable resistor is thus used for receiving the VHF bands, the design is made such that an additional switch or the like is used to switch a tuned voltage or a circuitry between the third and forth channels so as to equally space the scale characteristics from the first to twelfth channels because the frequency range between the third and forth channels is wide.

However, the addition of the switch makes a drive mechanism necessary for driving the switch synchronously with the variable condenser assembly having the variable resistor. Moreover, the scale plate is required to have such an accuracy as to be switched between the third and fourth channels. The intention to enhance that accuracy is inevitably limited by the disposition of the drive mechanism in addition to the disposition of the switch and the variable condenser assembly with the variable resistor in their qualities and accuracies.

The prior art thus far described is troubled by the problems in the high integration, the number of assembling steps and the improvement of the switching accuracy of the products Moreover, the requirement for the switch drive mechanism causes an increase in the cost for the products.

It is an object of the present invention to provide an improved variable condenser assembly.

According to the present invention, there is provided a variable condenser assembly for having its capacitance made variable as a rotor shaft is turned, comprising: a variable condenser having a plurality of terminals and having said rotor shaft made turnable at its front base; a switch having its electrodes formed in the front base of said variable condenser and its sliders fitted around said rotor shaft for contacting with said electrodes to provide electric conduction inbetween; and a variable resistor having a group of elements mounted on the terminals of said variable condenser and its sliders fitted around said rotor shaft for contacting with the terminals thereof to provide electric conduction in between so that said rotor shaft may act as a common drive shaft for said variable resistor and said switch, whereby the capacitance of said variable condenser and the resistance of said variable resistor may be varied and said switch may be turned on or off as said rotor shaft is turned.

In the present invention, therefore, the sliders of a variable resistor and the sliders of a switch are so fitted on a rotor shaft acting as the drive shaft of a variable condenser that the capacitance of the variable condenser and the resistance of the variable resistor may be varied and the switch may be turned on or off as the rotor shaft is turned.

According to the present invention, the rotor shaft of the variable condenser and the drive shaft for the variable resistor and the switch are made common and assembled with a slider group. As a result, the common single shaft can vary the capacitance and the resistance and can turn on or off the switch while making the drive mechanism unnecessary for synchronously driving the switch and the variable condenser having the variable resistor as a whole product. Thus, the present invention can contribute to the high integration and the reduction of assembly steps of the product and can improve the switching accuracy of the switch.

A variable condenser assembly embodying the present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Fig. 1 is an exploded perspective view of the variable condenser assembly; and Fig. 2 is a fragmentary sectional view of the assembly of Fig. 1.

The variable condenser assembly includes a control switch and a variable resistor (which will be shortly referred to as a "varicon with SW and VR").

As shown in Figs. 1 and 2, the varicon with SW and VR is constructed of a small-sized variable condenser 1 using a fiim (although not shown) as its dielectric element, a switch 8 and a variable resistor 9. The switch 8 is composed of: a pair of electrodes 1c and 1d, which are formed in the upper surface of a front base 1 h of the variable condenser 1; and a slider support 2 which carries and supports sliders 4a and 4b adapted to contact with the paired electrodes 1c and 1d, respectively, for providing electric conduction inbetween.The variable resistor 9 is composed of: a base 5; an element 6 formed with a resisting layer 6c and a collecting layer 6d; and the slider support 2 which carries and supports sliders 3a and 3b adapted to contact with the resisting and collecting layers 6c and 6d, respectively, for providing electric conduction inbetween.

From the upper surface of the front base 1 h of the variable condenser I, as viewed from Fig. 1, there project both a rotor shaft 1 b for turning a rotor plate (although not shown) arranged in the variable condenser 1, and a plurality of terminals 1a for constituting posts to support a stator plate (although not shown) and to provide electric conduction with the same. These rotor shaft 1b and terminals 1 a have their respective positions spacings standardized so that the variable condenser 1 may be mounted in an audio device or connected with a circuit base (although not shown).

Thus, in the variable condenser 1 of flexibie usage, the standards are fixed irrespective of the value of the capacitance and the number of sections (i.e.

bands to be tuned). For the variable condenser 1 to be mounted in the audio device or connected with the circuit base, moreover, the terminals 1 a are projected, too, from the lower side of the variable condenser 1 to form legs 1 g.

The electrodes Ic and Id forming partofthe switch 8 are fixed in the upper surface of the front base of the variable condenser 1 by the insert moulding, for example, such that the electrode 1 d is formed generally in an annular shape around the rotor shaft Ib of the variable condenser 1 whereas the electrode 1c is formed generally in a semicircular shape around the former electrode 1 d so that the switch 8 may be turned on within a predetermined angular range. These electrodes Ic and Id have their respective outward lead terminals le and li bent generally at a right angle around the outer edges 1k of the front base I h of the variable condenser 1 and along the sides of the variable condenser 1 to project from the lower side of the variable condenser 1, as shown in Fig. 1.Reference numeral 1j denotes a switching position, and numeral If denotes an earth lead.

A slider group 10 is composed of the slider support 2 and a plurality of pins 2a which are anchored in the two sides of the slider support 2 for fixing slider units 3 and 4. The slider group 10 is formed therein mounting holes 3c and 4e for anchoring the pins 2a. Thus, there are fixed on the slider support 2 the slider units 3 and 4 which carry the sliders 3a and 3b, and 4a and 4b forming part of the switch 8 and the variable resistor 9, respectively.

Those slider units 3 and 4 are placed on the slider support 2 and are then fixed by the pins 2a of the slider support 2. Moreover, this slider support 2 is formed generally at its centre with a shift inserting hole 2b in which the rotor shaft 1 b of the variable condenser 1 is inserted and fixedly press-fitted.

An element group 11 is composed of: the element 6 which is formed with the resisting layer 6c on its outer side and the collecting layer 6d on its inner side and which is equipped with four terminals 7; and the base 5 in which the element 6 is mounted and retained. This element 6 is formed generally at its centre with a shaft inserting hole 6a in which the rotor shaft I b acting as the drive shaft for the variable condenser 1 is loosely fitted. The terminals 7 are fixed by grommets 7a in eyelet holes 6b formed in the element 6.The base 5 has an element mounting portion Sc for mounting and retaining the element 6 therein, and the portion Sc is formed at its central portion with a shaft inserting hole 5b, in which the rotor shaft 1 b is loosely fitted, and at its outer edge with a plurality of terminal inserting holes 5a which can be press-fitted on the terminals la of the variable condenser 1. The shaft inserting hole 6a of the element 6 and the shaft inserting hole 5b and the terminal inserting holes 5a of the base 5 are arranged in such positions as to align with the rotor shaft 1 band the terminals 1 a of the variable condenser 1, respectively.Thus, the element 6 is retained with its resisting and collecting layers 6c and 6d being positioned underneath, and the terminals la are press-fitted and fixed in the terminal inserting holes 5a.

As a resuit, the variable condenser assembly thus far described is integrated with the variable condenser 1, the switch 8 and the variable resistor 9 by press-fitting the rotor shaft I b in the shaft inserting hole 2b of the slider support 2 and the terminals la in the terminal inserting holes 5a of the base 5 at the projecting side of the rotor shaft 1 b of the variable condenser 1. Thus, the variable condenser 1, the switch 8 and the variable resistor 9 can be easily assembled merely by forming the shaft inserting hole 2b in the slider support 2 and the terminal inserting holes 5a in the base 5.Thanks to the press-fitted strueture of the shaft inserting hole 2b of the slider support 2 and the rotor shaft 1 b of the variable condenser 1, the rotor plate (although not shown) in the variable condenser 1 and the sliders 3a, 3b, 4a and 4b fixed on the slider support 2 are turned together, as the rotor shaft 1 b is turned so that the capacitance of the variable condenser 1 and the resistance of the variable resistor 9 can be varied together while the switch 8 is being turned on or off by the common shaft.

The variable condenser described is constructed such that the electrodes of the switch are formed in the front base of the variable condenser, such that the element group of the variable resistor is mounted on the terminals of the variable condenser, and such that the slider group of the variable resistor is press-fitted on the rotor shaft of the variable condenser so that the capacitance and the resistance can be varied and the switch can be turned on or off as the rotor shaft is turned. Thus, the production can dispense with any drive mechanism for synchronously driving the switch and the variable condenser having the variable resistor to provide practical effects in the high integration and the reduction in the assembly steps of the product and in the improvement in the switching accuracy.

Claims (3)

1. A variable condenser assembly for having its capacitance made variable as a rotor shaft is turned, comprising: a variable condenser having a plurality of terminals and having said rotor shaft made turnable at its front base; a control having its electrodes formed in the front base of said variable condenser and its sliders fitted around said rotor shaft for contacting with said electrodes to provide electric conduction in between; and a variable resistor having a group of elements mounted on the terminals of said variable condenser and its sliders fitted around said rotor shaft for contacting with the terminals thereof to provide electric conduction inbetween so that said rotor shaft may act as a common drive shaft for said variable resistor and said control, whereby the capacitance of said variable condenser and the resistance of said variable resistor may be varied and said control may be turned on or off as said rotor shaft is turned.

2. Avariable condenser assembly according to Claim 1,furthercomprising a slidersupportfixing thereon the sliders of said variable resistor for varying the resistance of the same and the sliders of said control for turning on or off the same.

3. A variable condenser assembly substantially as hereinbefore described with reference to the accompanying diagrammatic drawings.