Patent GB-157912-A (GB)
Title: Electric ignition apparatus for internal combustion engines
IPC: F02P1/00
Filed: 1921-01-10
Abstract: 157,912. Mõdler, F. L. May 7, 1919, [Convention date]. Void [Published under Sect. 91 of the Act]. Interrupters, mechanical, for use in conjunction with ignition apparatus in high speed internal combustion engines, in which the ignition circuit is opened and re-closed mechanically, are provided with means to earth or break the ignition circuit immediately after the spark has occurred. Fig. 1 shows a form of interrupter giving four interruptions per revolution. The shaft a carries an interrupter ring b made of insulating material, which has four projecting cams. A two-armed lever c has its two arms elastically connected by means of a torsion spring and carries projections k, m adapted to be actuated by the cam surfaces of the ring b, and at one end carries a contact which normally touches a fixed earthed contact f. The internal surface of the ring b carries four metal segments which form projections of a supporting spider c, these segments thereby being connected to earth. A small stationary carbon brush d rubs over the segments, the brush d and the lever e being connected to one pole of a primary ignition circuit comprising a battery i and coil h, the other pole of the ignition circuit being earthed. Almost immediately after the circuit is interrupted at f, the ignition circuit is earthed by the brush d thus preventing the possibility of more than one spark passing at each interruption. The projection m is raised by the following cam shortly after the interruption, thereby assisting the re-closing of the contacts. Fig. 3 illustrates a modification in which two pairs of contacts are employed one at each end of the two-armed interrupter lever, a separate interrupter ring being provided for each engine cylinder. The contacts d serve to interrupt the ignition circuit causing a spark to pass when the cam a strikes the projection g, and an instant later the projection e passes off the cam, thus opening the contacts c cutting off the ignition circuit from this interrupter ring during the firing of the other cylinders. In the form shown in Fig. 2 a separate ring is provided for each cylinder, the interrupting cam a holding the contacts apart after each interruption until the other interrupter rings have functioned. The projection on the auxiliary arm in this case slides in a groove c in the cam a thereby assisting in the opening and closing of the contacts. A carbon brush cooperating with earthed segmental contacts is provided in this form of interrupter as in the form illustrated in Fig. 1. Fig. 5 illustrates the above type of interrupter mounted with a distributing device. The necessary number of rings 1 - - 4 are mounted with a short-circuiting device c of the type described on a common shaft passing through a metallic casing a. A cover e of insulating material is secured non-rotatably to the casing by suitable clips. A metal terminal f having a non-circular shank passes through the centre of the cover, and carries internally a metal member having multiple spring arms g, Fig. 4. A face cam d, carried by the interrupter shaft in its rotation over inclined surfaces i on the arms g, thereby depresses them in turn against contacts h, arranged circumferentially, the central contact f being connected to the high tension source, and the radial contacts h to the respective engine cylinders.