US2041280A - Condenser - Google Patents

Description

May 19, 936- M. H. BENNETT 2,041,280

CONDENSER Filed Aug. 50, 1934 I 2 Sheets-Sheet l v \n\\\\\\\\\\ -& J I6 I 15 a W 9ATTORNEYS May 1936- M. H. BENNETT 2,041,280

CONDENSER Filed- Aug. :0, 1954 2 Sheets-Sheet 2' lNVE OR Patented May 19, 1936 CONDENSER Morris H. Bennett, Prospect, Conn, assignor to Scovill Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Application August 30, 1934, Serial No. 742,059

4 Claims.

densers.

An object of the invention is to provide a variable condenser in which the rotor and stator 5 plates are in permanent predetermined spaced relation to each other, and in which this result is secured by a novel method of constructing the condenser, this being accomplished without the use of screws or other adjusting means. in Another object of the invention is to provide a condenser and method of constructing it which will lower the cost of manufacturing.

Another object is to provide a novel rotor plate unit and novel means for insulatably and perl-w manently securing this unit to the rotor shaft.

A further object of the invention is to provide, in connection with the rotor plate unit, a trimmer condenser carried by the frame, one of whose plates is provided with one or more arms making wiping contact with the rotor plate assembly throughout its range of movement.

Still further objects and advantages of the invention will appear from the following description taken in connection with the accompanying drawings, which illustrate a preferred embodiment of the invention, and in which:

Fig. l'is a top plan view of the preferred embodiment;

' Fig. 2 is aside elevation thereof; Fig. 3 is a transverse section therethrough;

Fig. 4 is an enlarged fragmentary sectional view showing part of the rotor plate unit and its insulated permanent attachment to the rotor shaft; V Fig. 5 is a top plan view, partly in horizontal section, showing the trimmer condenser and its wiping contact arms; Fig. 6 is a fragmentary vertical transverse sectional view showing in further detail the trimmer condenser structure of Fig. 5, and 40 Fig. '7 is a fragmentary transverse sectional view through the rotor shaft showing the mounting for it in one of the condenser frame ends.

Referring in detail to the drawings, a condenser frame has front and rear end plates l2 and I4, respectively, and side plates l6 having an integral bottom portion l8. provided with suitable openings 20 for the insertion of the spacing combs hereinafter referred to.

The sides and bottom are provided with slotted I re-entrant portions 22, in which are placed a plurality of stator plates 24, the edges of the stator plates protruding through the slots being staked over to lock the stator plates permanently and rigidly in predetermined desired relation.

In accordance with'the invention, a rotor plate The present invention relates to variable con-,

unit is provided and includes a plurality of rotor plates 28. In assembling the rotor plate unit, the rotor plates are properly positioned in an assembly jig and a tie bar 3!! placed in position with a plurality of tongues 32 on each'- rotor plate pro- 5 acting through slots in the tie bar. The tongues are then staked over and the rotor plates of the unit are thereby rigidly and permanently held in desired spaced relation.

The rotor plate tie bar 35 has a channel por- 10 tion 34 fitting the curved cut-outs in the rotor plates, and, as shown in'the drawings, each rotor plate is provided with three tongues staked to the tie bar channel port-ion and with two tongues staked to the flat part of the tie bar extending 15 along-the upper edges of the rotor plates.

This structure, constituting the rotor plate unit, is placed in the frame .with the rotor plates properly interleaved with the stator plates. accurate interleaving being insured by the use of spacing g0, combs insertible through openings 20, or by other desired means, and while so held the rotor shaft is placed in position in the frame.

The rotor shaft is provided with a plurality of passages extending diametrically through it and 25 in alignment with each other. These holes are counterbored for the reception of cylindrical porcelain washers 38. A bridge plate or assembly plate 40 has. a seating pocket for a second porcelain washer 42. The porcelain washer seats in 30 the shaft and in the assembly plate are deep enough to receive the washers up to about half the height of the washers, and when the assembly plate and washers are in position, a rivet or eyelet is inserted through the washers and through an 35 opening in the washer seat of the assembly plate slightly" greater in diameter than the rivet or eyelet. The rivet or eyelet 46 extends through the 'shaft opening and is then closed over at both ends (Fig. 4), thus providing an exceptionally 4o rigid construction with excellent electrical insulation. I

The shaft carrying the assembly plate is placed in the condenser frame and is preferably assembled therein so that it cannot moveaxlally. As 4, indicated in Fig. 4, the assembly plate 40, carried by the shaft, lies within the channel portion 34 of the rotor plate tie bar.

At its forward end the rotor shaft 4| has fixed to it a disc 50 having two stop shoulders 52 and 50' 53 to limit the rotation of the shaft in either direction by contacting a lug 54 punched out of the end plate l2. The disc 50 serves to retain the balls 56 in their raceway 5B in the front end plate and to prevent movement of the rotor shaft axialll ly to the right as viewed in Fig. 1. A pointed pressure screw ill, carried by the rear end plate ll, supports the other end of the shaft and prevents it "from moving to the left.

While the rotor plate units are held in interleaved position by combs or otherwise, the assembly plate 40 is soldered along its upper edges,

' as at 65, to the rotor plate tie bar 30 along both means that can permit the destroying of this adjustment by vibration or otherwise. Moreover, it will be noted that expensive adjusting operations are eliminated.

Referring to the trimmer construction, the frame side It is provided with an opening II, in which is inserted the lower end of a flexible movable trimmer condenser plate 14, whose upper end is movable toward and from a fixed trimmer condenser plate It by adjusting nut 18 on a screw 80 carried by the frame side plate. The fixed plate 16 bears on an-insulator 82 between itself and the frame side I 6 and is provided with an opening through which the screw 80 extends. A sheet of mica 84, or similar material, is located between the fixed and movable plates of the trimmer condenser. The fixed plate 16 is provided with attaching portions 88 passing through openings in the insulator 82 and bent over to lock the fixed plate in position as shown in Pig. 5.

At each end the fixed plate 16 is provided with a flexible arm 90 having a turned-up end 92 bearing on an edge of the channelportion 34 of the rotor ,tie bar. The fixed plate 16 is also provided with a pair of ears 94 which may be used as $01- derin'g lugs to make the connection. It will be noted that the wiper arms 90 conduct energy from the rotor directly to the trimmer plate I8;

that a minimum of insulation is employed; and

- that the movable plate 14, being grounded, acts as a shield to prevent stray electrostatic fields from adjacent trimmers afl'e'cting each other. Moreover, it will be seen that there are no joints between the wiper arms 90 and fixed trimmer plate 16 to become defective or to loosen and cause poor connection, leading, in a radio set, to consequent noise. Also, the inductance of the wiper arms is constant regardless of the position of the rotor unit.

What is claimed is:

1. In a condenser, and in combination, a rotor unit comprising a plurality of rotor plates, 8. tie

bar to which the several rotor plates are rigidly .secured, a rotor drive shaft, an assembly plate secured in fixed integral metallic relation to said tie bar, an insulating washer between the shaft and said assembly plate, a second insulating washer on the opposite side of the assembly plate, the assembly plate having an opening and the shaft having a diametrical bore in line with said washers, and a rivet passing through said bore, opening and washers and headed over at its ends to secure the shaft and assembly plate together in rigid and insulated connection.

2. In a condenser, and in combination, a rotor unit comprising a plurality of rotor plates having arcuate cut-outs about the shaft, a tie bar having a flat portion and a channel portion corresponding to said cut-outs, a plurality of tongues on each of said rotor plates extending into openings in the tie bar and staked over therein, an assembly plate bridging and soldered to the channel portion of the tie bar, and means for rigidly connecting the shaft to-said assembly plate.

3. In a condenser, and in combination, a rotor unit comprising a plurality of rotor plates having arcuate cut-outs about the shaft, a tie bar having a flat portion and a channel portion corresponding to said cut-outs, a plurality of'tongues on each of said rotor plates extending into openings in the tie bar and staked over therein, an assembly plate bridging and soldered to the channel portion of the tie bar, an insulating washer between the shaft and said assembly plate, a second insulating washer on the opposite side of the assembly plate, the assembly plate having an opening and the shaft having a diametrical bore in line with said washers, and a rivet passing through said bore, opening and washers and headed over at its ends to secure the shaft and assembly plate together in rigid and insulated connection.

4. The herein described method of assembling the parts of a condenser in permanent adjusted relation which comprises rigidly and permanently securing the stator plates in a frame, rigidly and permanently securing the rotor. plates to a tie bar, interleaving the rotor plates with the stator plates, inserting temporary spacing members between the two sets of plates to eifect predetermined spacing, mounting the shaft in the frame and confining it against axial movement, and, while the temporary spacing members are still in place, rigidly and permanently securing the shaft to the tie bar.

MORRIS H. BENNE'I'I

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