Now secure a piece of unstretchable leather (belting is preferable). This belting or leather should be slightly longer than the pattern you have just completed and sufficiently wide to embrace the curve; about twelve to fifteen inches wide for the average clutch will be sufficient, and about three-sixteenths of an inch thick.
Cut out the paper pattern and lay it on the leather belting as shown in [Fig. 108], and cut out with a sharp knife, leaving one-half inch over at each end as a safety measure and for mitering the joints. Fit this leather to the cone and cut the ends the exact size, miter the ends and cement with a good leather cement. Be sure that you have the rough or flesh side of the new facing on the outside; rivet it firmly in place and smooth down the rough spots with a piece of coarse sand paper, clean off all dirt, grease, and grit, especially the grit from the sand paper, as this will grind and score the smooth surface of the flywheel and cause clutch slipping. Paint the leather with Neat’s foot oil and the clutch is ready to be assembled and adjusted.
Cone Clutch Cleaning.—Cone clutches usually do not require any special care or cleaning unless oil or grease, other than (Neat’s foot or castor) are applied accidentally or by mistake to the leather face. If this happens the grease must be thoroughly cleaned off of the leather face with kerosene or gasoline otherwise the clutch will not hold. After the clutch leather has been washed allow it to dry for twenty minutes and apply a thin coat of Neat’s foot oil evenly on the leather face before reassembling the clutch.
CHAPTER XXIX
TRANSMISSIONS, TYPES, OPERATION AND CARE
Transmission came into use with the application or adoption of the internal combustion engine as a factor in motor car propulsion.
As this type of engine develops its power by a rapid succession of explosions in the combustion chambers, each explosion delivers an impulse or power stroke to the piston, which in turn sets the crank shaft and flywheel to revolving. The momentum gathered by the crank shaft and flywheel may therefore be termed the power for duty, or in other words, unless there is momentum or carrying motion at this point, there will be little or no power for duty.
This brings us up to a point where it is easy to see that a rapid series of explosions are necessary to gain carrying momentum or power to move a dead weight load. As this motional power could not be applied to the load without serious damage to the gears and bearings, it was necessary to invent a device to gradually transmit or apply the power to the movable load by graduating the leverage. This resulted in the development of the automobile transmission. The natural way of doing this at first seemed to be by applying the power to the load by frictional slippage. Many ingenious devices of this sort were tried out without much success until the driving and driven disc type made its appearance.
[Fig. 109] shows the driving and driven disc type of friction transmission. This type of transmission is not being used by any of the present day manufacturers of automobiles, but may still be found on some of the three and four-year-old models still in operation.
A, the drive shaft, is squared and slides backward a distance of three inches through a squared sleeve extending from the hub of the flywheel. The action of this shaft is controlled by a leverage arrangement to a foot pedal. B, the steel plate driving disc, is attached to the end of shaft A, and drives C, when held back against it by pressure on the foot pedal. Disc C can be slid in any position on the jack or cross shaft D, and is controlled by a leverage arrangement connected to a hand lever. The various speeds are obtained by sliding disc C into different positions and contacts on the left side of disc B. Reverse speeds are obtained by sliding disc C over center where it forms contact on the right side of B and is driven in an opposite direction.
