OPERATION
A clutch always consists of two parts, one part which is attached to the flywheel, and another part which operates on or against the part formed by the flywheel.
While there are five to seven different types of clutches, but two types are used by the majority of automobile manufacturers. The single or multiple disc clutch is used almost exclusively in unit power plant construction, while the cone type is used when the transmission is carried in a separate unit.
[Fig. 105] shows the cone clutch with its three adjusting springs and clutch brake. The cone is shown in a lighter color than the flywheel. It has a funnel-shaped surface with a slant or angle of from thirty to thirty-eight degrees. The slanted surface is faced with leather and fits into the rim of the flywheel which has been ground to the same slant. The cone clutch is not attached to the flywheel but forms a part and revolves with it when the faces are in contact. The cone is carried on a separate short shaft which extends into the transmission case. This shaft carries a steel plate or disc at the front end to which the cone which slides on the shaft is anchored by studs extending from the plate through the cone. The studs usually number three or four and carry a two to three inch spring on the outer end back of the cone. The cone is backed out of contact with the flywheel face, against the tension of these springs, in a toggle leverage connected to the foot pedal. The clutch brake shown in [Fig. 105] is adjustable and makes contact with the rim of the cone retarding the rotation when the cone is drawn out of contact with the flywheel.
Cone Clutch Care.—The leather face of the cone should receive 5 to 7 drops of Neat’s foot oil every thirty days. A grease cup will be found on the cone which provides lubrication for the shaft on which the cone slides. This should be given a half turn every second day.
Cone Clutch Adjustment.—The three studs extending through the cone, have a lock nut adjustment on the outer end, and the cone may be adjusted up to make a stronger face contact by loosening the lock nut and turning the inner nut to the right. This strengthens the spring tension and causes the contact faces to set more firmly. This adjustment, however, should take place only when clutch slipping is noted. Only a little movement of the nuts is necessary, and all three or four nuts should be taken up a like amount in order to prevent the cone from running out of line or making uneven contact.
[Fig. 106] shows the multiple disc clutch used almost exclusively in connection with the unit power plant. This type of clutch consists of a set of plates attached and driven by the flywheel, and another set of plates or thin discs attached to the drive shaft. The drive shaft plates operate between the flywheel plates. The contact is frictional and the plates are held together by spring tension.
Fig. 106. Multi-Disc Unit Power Plant, Clutch and Transmission