Patent GB-813431-A (GB)
Title: Improvements in or relating to electrical capacitors and to the manufacture thereof
Inventor: COTTON JAMES HENRY
IPC: H01G4/30
Filed: 1954-06-03
Abstract: 813,431. Capacitors. DUBILIER CONDENSER CO (1925), Ltd. Sept. 1, 1955 [June 3, 1954], No. 16451/54. Class 37. Parallel-plate capacitors are manufactured by assembling one or more dielectric sheets bearing on at least one surface a plurality of electrode areas on posts together with foil strips which serve as terminal connections in the finished capacitors, the posts penetrating the dielectric sheets and foil strips and serving as rivets in the finished capacitors or forming holes in which rivets are inserted and the sheet or sheets being cut after assembly between the electrode areas to provide a plurality of individual capacitor units. As illustrated, the capacitor structure comprises one or more dielectric sheets A, Fig. 1, each having a plurality of spaced metallized coatings on each surface thereof, the metallized areas on each surface being opposite corresponding areas of the opposite surface and the sheets being provided with apertures B arranged in two rows, the metallizing on one surface of each sheet extending up to the apertures in one row only and the metallizing on the opposite surface extending up to the apertures in the other row only, the structure being assembled upon supporting posts F which are arranged in two rows corresponding to the apertures B. The completed assembly is then severed between the metallized areas to provide a plurality of individual capacitors. The supporting posts F preferably also serve as eyelets or rivets and have terminal leads G secured thereto, or as shown, formed integrally therewith. The posts F are arranged in two rows and apertured metal strips D1, D2 are fitted over the posts. An unmetallized insulating plate H having apertures similar to those in the plate A is then placed over the strips D1, D2 and the strip D1 is then folded over so that a further set of apertures fits over the corresponding posts F. A metallized plate A is then fitted over the posts, the other strip D2 is folded over and its further set of apertures fitted over the corresponding posts and the structure is completed of the addition of a further unmetallized plate H1. The upper ends of the posts F are then deformed to rivet the assembly together; alternatively the posts F are replaced by eyelets or rivets which are then deformed to clamp the assembly together. The assembly is then cut along the gaps between the metallizing thus providing in the examples shown, five individual capacitors. These capacitors are then sealed with a thin wax or varnish coating. In a second embodiment, shown in Fig. 6, the assembly comprises more than one metallized plate A, so that each final individual capacitor comprises a stack of metallized dielectric elements. In a modification, Fig. 8 (not shown), the dielectric sheets are metallized on one side only and at least two are used in the manufacture of the capacitors, being placed one above the other on the posts with the terminal strips interleaved between them. The dielectric employed may be mica or a synthetic plastic. Specification 550,419 is referred to.