Change-down prevention mechanism for vehicular automatic transmission - is engaged and disengaged by electromagnet responsive to ignition switch, tachometer, brake pedal and selector lever

摘要

The mechanism has a pawl (8) on the gear selector (5) which engages a ratchet (9) which is pivoted about an axis (10) through the gear selector housing (7) and has three catches (12-14), one or other of which contacts the pawl (8) in all ratios/positions except Neutral. Selections of ratio 2 (from 1), Drive (from 2) and Park (from Reverse) can be made manually, overcoming a spring (11). The opposite moves are impossible unless the ratchet (9) is positively disengaged by the electromagnet (19). ADVANTAGE - Simple mechanism preventing engine overspeed through manual selection of too low gear, also serves as brake-lock.