GB112540A - A Safety Device to Prevent a Back Stroke while Starting an Internal Combustion Engine by a Hand Crank. - Google Patents

Abstract

112,540. Bloxam, A. G., (Bosch, R., [Firm of]). Feb. 27, 1917. Turning-gear.-To prevent reversal of the engine at starting, the movement of the starting- handle to engage the engine shaft is utilized to cut out the ignition in the event of the timing being so far advanced that ignition would occur before the crank passes the dead centre. In the arrangement shown in Fig. 4, b is the primary winding of a magneto and c, d the interrupter. During normal running, an igniting current is generated in a secondary winding (not shown). In the event of the timing-lever f being set in its advance-spark position and the starting-handle l being engaged with the engine shaft, contacts p, q are closed and the primary current earthed through the connexions b, t, u, 10, 8, 6, 4, 12, 5, 7, 9, 11, p, o, and q. By turning the lever f into its position for retarded ignition, the connexions between the contacts 6, 7 and 8, 9 are broken, thus closing the primary circuit and enabling ignition to occur. According to a modified construction, a rotating switch is mounted upon the armature shaft and carries a carbon contact which engages contact pieces in an insulated disk. When the switch portion carrying the carbon contact is set for advanced ignition, any movement of the starting-handle closes a switch similar to that shown at o, p, q, Fig. 4, and earths the primary current. In a further modification, a rotary switch having a carbon contact, as in the modification referred to above, short-circuits the primary current as an alternative to earthing it. Cther modifications are described in which the invention is applied to magnetos having interrupters actuated by cams for breaking the primary circuit. In the arrangement shown in Fig. 10, an auxiliary magneto 36, actuated by the starting handle, supplies the current at starting. The main magneto 30 is connected to a distributor 35 in the ordinary way, the starting magneto being connected to the same distributor through a ring 41 and a contact 42 which is set so that ignition can occur only when the piston has passed the top dead centre. At starting, the auxiliary magneto is driven from the starting-handle through a flexible shaft 51 and the current from the main magneto is earthed by closing the switch p, q, o. The invention may be used in conjunction with battery ignition.