US2064620A - Means for applying a trimming condenser to a main condenser - Google Patents

Description

Dec. 15, 1936 D |BBY 2,064,620'

MEANS FOR APPLYING A TRIMMIIQG CONDENSER TO A MAIN CONDENSER Filed July 30', 1932 FIG. 1' 9 7 ll 8 I (O 4 6 h II P- l" l ll 0 In I] CE- WW: 30 l I I a I 27 I3 I I4 Z5 I 2 v 1 HI 3 26 a 2 I6 17 I f INVENTOR ALBION D. T. LIBBY Patented Dec. 15, 1936 PATENT omcs MEANS FOR APPLYING A G- con- TBIHMIN DENSER TO 'A MAIN CONDENSER Albion D. '1. Libby, East Orange, N. 1., assignor to Condenser Development Corporation, Newark,

Application July 30, 1932, Serial No. 626,452

3Claims.

This invention relates to improvements in the design of variable electrical condensers such as used in radio receiving sets.

In the design of gang condensers, it is the usual practice to provide each condenser unit with what is known in the trade as a trimmer. This trimmer condenser ordinarily consists of a single plate mounted so as to function in parallel with its associated main condenser unit, whereby the initial capacity of the main condenser may be slightly varied by adjustment of the trimmer plate.

It is also quite the usualpractice to provide the main condenserunits with some compensating means whereby the capacity curve of the condenser may be automatically varied over its-range in order that the various tunable circuits may be brought as near alike as possible to the maximum tuning point at various settings of the tuning dial. Various other features are sometimes specifled by the receiving set manufacturers so that the condenser manufacturer must be imposition to furnish condensersthat will meet all the various requirements which may or may not include the trimmer condenser.

If the gang condenser can be built and placed in stock without the trimmer condenser, but arranged so that the same may be readily added without changing the adjustment of the various Y units of the gang, much time and expense can be saved when an order is received requiring a trimmer plate. w

My invention is directed to means for quickly attaching the trimmer condenser without disturbing the normal calibration ofthe main condenser with which it is associated, so that if the condenser manufacturer, on receipt of an order, has condensers in stock without the trimmer, and a trimmer is required, the same may be quickly added; orif the condensers in stock have trimmers thereon and the order calls for tuning condensers without trimmers, these trimmer plates may be quickly removed without disturbing the adjustments that have already been made on the main condenser.

Another object of my invention is to provide means for mounting a trimmer condenser which is applicable to a gang condenser of the compact type; that is to say, one in which the condenser units are small or compressed in dimensions, as well as one where the mounting space isnot limited. Y

My improvement is shown in the annexed draw- 1 ing, in connection with a-two-gang condenser, but

it is to be understood that'any number of condenser units may be included in the gang. In the drawing:

Figure 1 illustrates a side elevation of a twogang condenser in which the groups of rotor plates are in partial engagement with their respective stator plates, one of the units of the gang being equipped with a trimmer plate, while on the other unit the trimmer plate has been removed to show certain details.

Figure 2 is a fragmentary sectional view on the line 22 of Figure l.

Figure 3 is a view on an enlarged scale of the preferred form of means for'mounting the main and trimmer condensers.

In the drawing, 1 is a frame having end- support plates 2 and 3 carrying an operating shaft 4 suported preferably on anti-friction bearing members carried in the races 5 and 6, all as shown and described in Cramer Patent 1,800,719, issued April 14, 1931. The shaft 4 carries sleeves I and 8 to which the rotor groups of. plates 8 and II are attached in any satisfactory manner. As illustrated, the outer ends of the rotor plates 0 are fastened together by tieplate ll, while the outer ends of the groups of rotor plates III are fastened together by tie-plate l2.

The side members of the frame I have openings l3 and It therein with upturned lugs l5 and It projecting a short distance into these openings. Fastened to the lugs I! and it in any satisfactory manner, as by rivets II, are insulators II. To the other ends of the insulators I. are attached the stator group of plates IS. The plates is are provided with notches or recesses 20 over which a tie-bar II is positioned, and to which tie-bar the plates I! are fastened in any satisfactory manner.

' screw 23', while having an external thread 2|,is

also provided with an internal thread 25. The internal thread llis'adapted to receive an auxiliaryfastening means or screw 26 which latterscrew is-adapted to mount the trimmer condenser plate 21 on the insulator It. It will be seen from Figures 2 and 3 that the trimmer plate will be clamped by the auxiliary "screws 26 against the heads II, to the main fastening means or screws The trimmer condenser plate 21 overlaps the frame I as'shown in Figures 1' and 2, and is kept from electrical contact therewith by an insulator 29, and adjusted with respect thereto by means of an adjusting screw 30 insulated from the trimmer plate 21 by an insulator 3|. The lower end of the trimmer plate 2'! ends in a terminal 32 to which electrical connections may be made. Electrical connection to each stator may be made by means of a small clip permanently fastened under the head 28 of the screw 24; or as is some times done, it may be made by the clip being mounted under the heads of the corresponding standard screws on the opposite side of the condenser in the usual manner.

From what has been said, it will be readily understood that the main fasteners or screws 23 which are used for mounting the main condenser as explained, are much heavier than the screws 26, and when the main fastening screws 13 are set up, the main condenser is rigidly held in place. Since the auxiliary screws 26 are independent of the mounting screws 23, it will be seen that the trimmer plate may be put on or taken off without in any way disturbing the main mounting screws or the setting of the main condenser, and no additional mounting means are required on the insulators l8.

Having thus described my invention, what I claim is:

1. For an electrical condenser having a frame and relatively movable sets of elements carried thereon and also having means for attaching one set of said elements to at least two insulators carried by the frame, said attachment means including members going through the insulators; a trimmer condenser plate adapted to be quickly mounted on the insulator by means directly engaging said attachment members but without disturbing the same, and means for adjusting the capacity position of said trimmer plate with respect to the frame.

2. For an electrical condenser having a frame and relatively movable sets of elements carried thereon and also having means for attaching one set of said elements to at least two insulators carried by the frame, said attachment means including members going through the insulators; a trimmer condenser plate adapted to be quickly mounted on the insulator by means of independently operated screws going directly into certain of said attachment members, and means for adjusting the capacity position of said trimmer plate with respect to the frame.

3. Means for mounting a trimmer condenser plate in operative relation to a main condenser and its supporting frame, said means including screws for assisting in fastening the main condenser'to the frame, at least a part of said screws having an internal thread as well as an external thread, and auxiliary screws threaded into the internal threads of said first-mentioned screws for holding the trimmer plate against the heads of said first-mentioned screws.

ALBION D. T. LIBBY.

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