This invention relates to a gear shitting device for an automotive constant mesh transmission system.
The transmission system in a vehicle multiplies the engine torque in accordance with the gear ration and supplies it to the wheels. A. typical four speed constant mesh transmission has four forward gear pairs and one reverse gear pair. The drive and driven gears are in constant mesh for all the gear pairs, the drive gears being mounted rigidly or integrally with the input shaft while the driven gears rotate freely over the lay shaft. To select a particular speed gear the freely rotating gear is made to rotate with its shaft using a star mechanism. The driver shifts the gear through the eternal gear shift mechanism and proceeds via internal gear shift mechanism to the star mechanism. The gear shift rod and gear shift star are parts of the internal gear shift mechanism.
In a typical four slot gear the angular distance to be travelled by the gear shift star to enter into the chosen gear is more, as it has to cover a 90 degree angle. This increases the gear shift time and gear shift effort abd reduces the life of the star mechanism as it has to overcome the actual loads to shift into a gear.
This invention reduces the shift time by reducing the angular distance to be travelled by the gear shift star during shifting. This can be accomplished by providing two sets of four slots 90 degrees apart in the gear each at an interval instead of the typical one set of 90 degree interval slot. Thus it reduces the gear shift time by approximately 50 %.

The gear shifting device for an automotive constant mesh transmission system, according to this invention, comprises a lay shaft, driven gear, a gear shiftrod, and a gear shift star, the said gear having eight slots positioned at intervals of 45 degrees, the gear shift star being inserted into the lay shaft of the system and the gear shift rod being fastened to the gear shift star; the gears of the said system being assembled on the lay shaft, whereby the gear shift star is tree to translate from one gear to the other through the slots provided in the driven gear.
This invention will now be described with reference to the accompanying drawings which illustrate, by way of example, and not by way of limitation, one of possible embodiments thereof,
Figs. 1 and 2 illustrating the embodiment in perspective and end views Fig. 3 illustrates the shift mechanism of the embodiment in the neutral position where it is not located inside the slots provided in the gear Fig. 4 illustrates the shift mechanism of the embodiment in the engaged position where the star is positioned inside the gear, thus engaging the gear.
The gear shifting device for an automotive constant mesh transmission system comprises a lay shaft, driven gear G2, a gear shift rod Rl, and a gear shift star SI, the said gear having eight slots T positioned at intervals of 45 degrees, the gear shift star being inserted into the lay shaft of the system and the gear shift rod Rl being fastened to the gear shift star SI, The entire assembly con be translated inside the lay shaft. The gears are assembled on the lay

shaft, whereby the gear shift star is free to translate from one gear to the other through the slots T provided in the driven gear. The lay shaft is supported on bearings and the input shaft gears rotate the constantly meshed lay shaft gears.
The earlier system uses four slots in the gear for the purpose of engagement. The shaft gear shift performs a linear translation motion inside the lay shaft thus passing the star through the gear shift slots. In the prenent invention, the gear is provided with 8 slots. Due to leas angular travel lor star to engage into a geur, the gear shift time is reduced by 50 % and the lite of the star is increased because of less fatigue as the star can enter the gear shirt slot in hull' the time.

We Claim:
1. A gear shifting device for an automotive constant mesh transmission system comprising a lay shaft, driven gear, a gear shift rod, and a gear shift star, the said gear having eight slots positioned at intervals of 45 degrees, the gear shift star being inserted into the lay shaft of the system and the gear shift rod being fastened to the gear shift star; the gears of the said system being assembled on the lay shaft, whereby the gear shift star is tree to translate from one gear to the other through the slots provided in the driven gear.
2. A gear shifting device for an automotive constant mesh transmission system substantially as herein described with reference to the accompanying drawings.