Gear-changing Made Easy
Page 49
If you've noticed an error in this article please click here to report it so we can fix it.
First Particulars of an Interesting Crossley Device
MANY attempts have, during recent years, been made to simplify the operation. of changing gear, but. with one or two notable exceptions, such devices have ne5t found their way int6 ordinary, production vehicles. The latest and, in our epinionv one of the best devices of this type hails from the works of Crossley Motors, Ltd., in Manchester. It takes the form of an auxiliary clutch which is located at the rear of the gearbox and which s in operation only at the time when the normal clutch between the engine an gearbox working. As will be seen from he drawings, the device is not unduly large ind as worked out by the Crosby engineers the assembly fits in nieel with the layout of the normal nassenge chassis. To the tail of the main shaft of the gearbox is keyed an inner race w ich has eight cam faces. Rollers of an inch diameter operate on these faces, i e miter race being controlled by a bani brake which Is connected to the clutci pedal. The action is therefore most simple.
When the clutch peda is depressed the gearbox is isolated'rem both the engine and the propeller shaft, so that the dutch brake (which, in all Crossley vehicles, is a powerful d viee) quickly stops the gears and shafts from rotating. The gear lever can the p be pushed through to any gear that ray be selected and the clutch released a ain, when the drive of both the main and auxiliary clutches is immediately t en up.
As will be seen from the sectional drawing, the cam faces in the • inner race of' the dutch are si ilar in sl,lape, so that the device work equally'well when the vehicle is being i riven forward or in reverse gear. It foil WR, therefore, that overrunning in eithe direction can take place without the engine being allowed to get into a " fr, " position.
We have actually tried gearbox as fitted to a 22-seater bu and we can • speak with coufidence as o its effectiveness. Without any prel inary instrue. Eon we made about 50 g ar changes in both upward and downward 'directions without the slightest sound emanating from the meshing pinions.
:Naturally, one has to drive in a sensible manner and avoid changing from, say, top to bottom at high road speeds. Indeed, when changing from top to third gear one .instinctively touches the accelerater before re-engaging the clutch. If this simple precaution be taken there is, noOthe slightest shock experienced by the passengers and it is possible to appreciate the feet that a _change of gear has been made only by the alteration in the engine note and by the slight gearbox whine on the indirect gears.
This new Crossley device is one which 'should prove a boon to operators of bus services involving a great deal of stopping and starting. The attendant operating gear of the auxiliary clutch does not seem materially to have increased the load on the pedal, so that drivers should not be fatigued on this score.