Automatic mechanical transmission system

Claim 1

An automatic mechanical transmission system (10) comprising compounded multi-ratio main and splitter auxiliary sections (48, 50) connected in series by means of a common mainshaft (68), wherein: said main section (48) has one or more countershafts (64, 66) driven from an input shaft (54) to the system, gears (74-78) fixed on each countershaft and in constant mesh with corresponding main mainshaft gears (80-84) mounted on and selectively jaw-clutched to the mainshaft, engagements of the jaw clutches (86-90) by shift means (122-126) being of the releasable non-blocked, non-synchronized variety, said mainshaft extending into the auxiliary section (50) as the input thereto, and; said auxiliary, splitter section has an output shaft (20) with an output gear (158) splined thereon to serve as overall output of the system, and one or more countershafts (132, 134) each having fixed thereon plural ratio gears (136-142) constantly meshed respectively with the output gear (158) and with auxiliary section gears (152-156) on said common mainshaft, and; these gears (158, 152-156) are selectively connectable non-rotatably either to the output shaft or to the mainshaft as appropriate by blocked jaw clutch means (162-168, 202-206) which are resiliently biased (178, 184) towards engagement when permitted by full alignment but not by substantial alignment of an array of conditional blocking projections (212­216), and; the blocking projections tend to rotate with respective engageable components (204, 206) of the jaw clutch, said full or said substantial alignment of the blocking projections (212-216) occurring only when said jaw clutch components approach synchronism, and; cooperating ramps (218-224) on said blocking projections (212-216) tend to bring about said full alignment from said substantial alignment only when no ratio of the main transmission section is engaged, the auxiliary section comprising also; shift means (190-196) to tend selectively to engage one of said jaw clutches and hence conditionally to engage one of said auxiliary ratios or said output gear when synchronism is present or at least approached with the main section disengaged, and characterized by a control assembly (38) for automatically operating said main section and auxiliary section shifting means, said control assembly having means to receive input signals (22, 28, 32, 36, 40), a central processing unit for processing said input signals in accordance with a program or set of logic rules and means to generate command output signals to said shifting means (34), said processing unit commanding changes in transmission ratio involving a change in auxiliary section engaged ratio in the sequence comprising shifting the main transmission section to neutral, completing a shift in the auxiliary section while the main section remains in neutral and thereafter reengaging the main transmission section, during each such ratio change; and wherein, said input shaft is driven by a throttle (24) controlled engine (14) through a master clutch (16), said input signals include at least a signal indicative of throttle position and a signal indicative of engine speed and said output command signals are effective to engage and disengage said master clutch (30) and to control fuel supply (26) to the engine independently of the operator throttle position, and said shifting sequence includes reducing the fuel fed to said engine prior to shifting said main transmission section to neutral.