A DEVICE TO FACILITATE GEAR CHANGING.
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Gears Automatically Brought to the Correct Speed for Meshing by Means of Friction Wheels.
AN ingenious device has recently .been designed and patented by Mr. :Percy 0. Rowland, of Chester Road, :Castle Bromwich, Birmingham, which is arranged as an adjunct to the ordinary type of gearbox with the object of bringing the gears to the correct speeds for qniet engagement. The action is ,entirely automatic and relieves the driver of the complicated manipulation of clutch, accelerator .pedal and gear lever, which the ordinary transmission demands if a noisy and damaging gear change is to be avoided.
The illustration reproduced shows the device fitted as an auxiliary to a gear.box of orthodox design, but it is obvious that a neater mechanism would result if the gearbox were designed from the start to incorporate this patented method for bringing the gears to the required speeds.
Mounted at the end of the main shaft and slidably splined thereto is a set of friction wheels opposite to which is a second set mounted upon a movable auxiliary shaft placed in line with the layshaft. This auxiliary shaft, when shifted sideways, causes the friction wheels to engage and, at the same time, conveys the drive to the layshaft through the medium of internal and external friction surfaces. The ratios adopted for the diameters of the sets of friction wheels correspond to the ratios of the gear within the box. The method of automatic control adopted displays considerable ingenuity. It will be seen that the slots in the gate are staggered instead of being placed opposite to one another, so that whenever a fresh gear is selected the lever must be brought to neutral and then moved sideways through the gate. This sideways movement is conveyed through rods and levers to the sliding friction wheels on the main-shaft extension so that the correct pair of wheels for the gear about to be engaged is automatically selected.
The other control is automatically operated when the clutch pechd is fully depressed, rods and levers then moving the auxiliary shaft sideways so as to bring the friction wheels into contact and, at the same time, couple the auxiliary shaft to the layshaft.
The action can best be understood by supposing that the driver has started off in first gear and wishes to change into second. He declutches, moves the gear lever into neutral and then moves it sideways through the gate until it is opposite the slot corresponding to second gear ; these operations result in the friction wheels coming into action and spinning the gear wheels at the required speed. The gears can then be engaged with the assurance of a quiet change. Exactly the same sequence of operations occurs whatever gear it is desired to engage.