Clutch (mechanics)

“ This form of clutch, it may be noted, is—or should be—always used in conjunction with a clutch of the friction order—i.e. whilst individual portions of gear may be connected with and disconnected from each other by the use of positive clutches, a friction clutch always connects the engine with the machinery so that the shock is taken up there. The teeth, notches, or projections of positive clutches require to be very carefully and accurately cut and properly hardened, for if they are not they are very apt to be chipped and to wear by the action of engagement. ”

“ If clutch adjustment is correctly maintained, clutch will cause very little trouble. Ease of gear shifting and service life of transmission gear shifter clutch dogs depend largely upon full disengagement of the clutch. Clutch adjustment is in two parts; namely, control linkage and spring tension. Do not adjust clutch spring tension before correcting control adjustment.
b. Clutch Control Linkage (fig. 22) . Operation of foot pedal, control cable, and clutch release lever actuates the push rod through hollow transmission shaft, disengaging or engaging clutch at will. ”

“ As a general rule, it is most advisable to set a clutch to take as hard a grip as it can without interfering with its releasing power. Where a clutch grips weakly, it is subject to undue wear owing to slippage, whereas a strongly regulated clutch absolutely prevents slippage wear. ”

“ The engine shaft has on its rear end the fly-wheel, which has a broad and heavy rim, turned to a conical shape inside. Close to this, revolving loosely on the shaft, is the clutch plate, a heavy disc with a broad edge so shaped as to fit the inside of a fly-wheel. It is generally faced with leather. A very strong spring presses the plate into the fly-wheel, and the resulting friction is sufficient to prevent any slip. Projections on the rear of the clutch engage with the gear-box shaft. The driver throws out the clutch by depressing a lever with his foot. ”

“ The motor and the main clutch shaft must be truly in line, but if these two main parts of the mechanism are separately attached to a weak frame, the frame twists and bends sufficiently to cause trouble with the clutch, because the one part of the clutch is not parallel with the other, and the inner cone only presses locally in the outer cone instead of fitting all round. Clutches used much when this is the case slip most when slipping is least wanted, soon cause much trouble, and only complete refitting and renewal of the cone surface can secure perfect action. ”

“ The power of the release clutch spring E, acting through the throwout-collar F, and the bell crank pivot G, drives the thrust shoes outwardly with a lever wedge toggle combination of powers against the overhanging, inward beveled face to the thrust ring H, since the parts on which they are mounted are backed against the cover wall or rigid end of the clutch casing. ”

“ When the clutch is disengaged there is no friction between the shaft B, and the throw out sleeve D. The thrust bearing takes the rotating drag of the clutch shaft, thereby eliminating the necessity for a brake to check the spinning action. The friction and power action is readily understood as, when the clutch is thrown in, all the rotating parts are friction locked into a single combination and revolve as one with the flywheel. ”

“ Pressure on a forked lever fulcrumed to the base of the machine, one end of which encircles the collar and the other end touching the lower stop lever, holds the clutch out of action. When the pressure of the forked lever against the collar is released, the clutch spring expands and the clutch rod moves the collar inward until the leather buffers are pushed against the inner surface of the driving pulley, causing the shaft to rotate. ”

“ The clutch shown is built to run in the direction indicated by the arrow, but such clutches may be built to run in either direction; they should always be run in the direction for which they are designed, so that the load may always come on the fixed arm. If the band be tightened slowly, there will be no sudden start or jerk on the rope, as the slip of the band will prevent the entire force of the grip taking effect at once; and after the drum reaches full speed, there is little or no slipping of the driving-band. ”

“ When the clutch makes x-1-x fast to either gear 2 or gear 2x, it causes it to let go of the other one, and that other one, thus released, runs around on the shaft independently, at the rate it is carried by its connection with the gear back of it. ”

“ As soon as the engine fires the starting pedal should be released immediately, as the overrunning motor clutch is operating from the time the engine fires until the starting gears are out of mesh. Since they operate at a very high speed, if they are held in mesh for any length of time, there is enough friction in this clutch to cause it to heat and burn out the lubricant. There is no necessity for holding the gears in mesh.
The motor clutch operates between the flywheel and the armature pinion for the purpose of getting a suitable gear reduction between the motor generator and the flywheel. ”

“ Study the friction clutch adjustments, but do not change them every time something stops the machine. It is much easier to break an adjustment than to make one.
A piece of metal from a squirt lodged between the mold disk guide or back of the rim on the disk will cause it to bind, placing more pull on the clutch. ”

“ In the crank-clutch cycles the clutch is used for the purpose of detaching the cranks from the spindle when the machine requires no driving, as in running down grade, but when once the clutch is gripped, it remains so till further power ceases to be required. Now, this is also just the action of all belt-pulley clutches, and between such action and that required in a lever-clutch cycle the difference is exceedingly conspicuous. In the crank-clutch cycle, as in other uses, the immediate solid grip is a matter of little concern ”

“ When the clutch is thrown out the pulley or sheave stands idle and the driving shaft revolves freely within the quill. As there is no contact between moving parts there is no wear. Jaw clutches should be used for drives demanding positive angular displacement. ”

“ If your clutch fails to hold, or sticks, it is not the fault of the clutch, it is not adjusted properly. And you may have it correct today and tomorrow it will need readjustment, caused by the wear in the shoes; you will have to learn the clutch by patience and experience. ”

“ When the car is to be started the clutch foot pedal (usually on the left side of the steering column) is pressed down. This throws the part attached to the drive shaft out of contact with the part attached to the flywheel, and in its backward movement it comes into contact with the clutch brake, as shown in Fig. 105, which stops it from revolving. The hand gear control lever is shifted into the first speed slot or position. The pressure on the foot pedal is then gradually released and the clutch is carried in by spring tension, and the car moves off at first speed. ”

“ The purchaser of a traction engine should see that it has a Friction [Pg 12] Clutch as an engine with a clutch is much more practical, convenient and safe to handle upon the road than one without a clutch. The matter of brackets, braces, gearing, traction wheels, axle, the manner in which the engine is mounted upon the boiler should be well considered as there are many kinds and styles, all of which have their merit “more or less.” ”

“ When operating a friction clutch, always draw or push the lever over gradually. By doing this the engine will start slowly and easily, while if the lever is jammed over suddenly, the engine will start with a jerk, which is liable to damage the traction gear. ”

“ Apropos of clutches, great care must be exercised in tightening them up while the shafting is in motion, for if the least bit overdone the clutch may start up or, on being locked for trial (according to the clutches' structure) , continue running without possibility of release until the main source of power be cut off. Nothing can exceed the danger of a clutch on a sprung shaft.
Heavily loaded shafting runs to much better advantage when center driven than when end driven, and what often constitutes an overload for an end drive is but a full load for a center drive. ”

“ The roller over which these chains pass is operated by a silent clutch, and in order to give an additional motion to the chains when a pan is full, and it is desired to bring the next pan into position, an additional clutch is caused to operate upon the roller. This clutch is kept out of gear with its pulley by means of a projection upon it bearing against a disk slightly greater in diameter than the pulley, and provided with two notches, into which the projection passes when the additional feed is required. ”

“ A fork or clutch rotates along with the shaft, and is capable of being moved longitudinally by a handle. When the clutch is moved towards the hoop, its arms catch those of the hoop, and cause the hoop to rotate and to communicate its rotation to the pulley by friction. ”

“ The most usual form of clutch is the friction cone, in which the fly wheel of the engine is utilized as the driving part, the rim being broad and thick, with its inner side funnel-shaped, or beveled. A metal cone that fits the bevel is carried on the end of a shaft of the transmission, the shaft at this point being square, to fit a square hole in the hub of the cone. ”

“ By moving the clutch over to the left, wheel a is held fast to and driven by the shaft upon which the clutch slides, whilst by moving it in the opposite direction, wheel a is freed, and wheel b held fast, and if the clutch be held stationary at a point midway between the two, both wheels are free and neither is driven. ”

“ When the clutch slips, it is due to wear, or to insufficient spring pressure, and a new adjustment is necessary; and it is frequently the case that the rod between the clutch and pedal must be taken up, this being the case, usually, where there is any wear in the clutch itself.
The disks are, usually, wholly of metal. Among other materials, cork is used to face friction surfaces of different clutch designs, and a variety of materials are constantly added to the list, which have good wearing qualities. ”

“ Where space is very much circumscribed, the clutch and the brake may be combined, by fitting a disk with brushes on one side, and projections on the other, so that it may be brought by a lever against a second disk, for transmitting motion, and against a third, fixed, for stopping it. ”

“ If the hill is a very steep one, as soon as the engine begins to lose speed, release the clutch, remove pressure from accelerator and, without applying the brake, shift to a lower speed gear. Let clutch in quickly and at the same time open accelerator wide. ”

“ The Apperson contracting band clutch excels for this work, because it never starts the car with a jerk whether flooded with oil or covered with sand, but always moves it off gently and smoothly under all conditions. ”

“ Great care must be taken that the clutch is not permitted to bind suddenly, for that would probably result in the stripping of the gears. If the low-speed gears are engaged, the checking would be so sudden, no matter how slowly the clutch might be engaged, that the shock would probably throw the passengers from their seats. ”

“ Ninth.—To shift to second speed advance the gas throttle until the car gathers a smooth rolling motion, press in the clutch pedal and allow three to five seconds for the brake to retard the speed of the clutch, then shift the lever to second speed and release the clutch pedal easily. ”

“ On old-style machines this adjustment was made by two nuts, one on each side of the clutch rod. Putting cardboard under the buffers will not satisfactorily drive the machine if something else is wrong. If there is too much packing under the leathers the starting and stopping lever will have no effect on the clutch and the machine will not stop properly. ”

“ But the good engineer knows better than to treat his engine that way.
Never attempt to pull your loads over a steep hill without being certain that your clutch is in good shape, and if you have any doubts about it put in the tight gear pin. Most all engines have both the friction and the tight gear pin. The pin is much the safer in a hilly country, and if you have learned the secret of the throttle you can handle just as big load with the pin as with the clutch, and will never tear your gearing off or lose the stud bolts in boiler. ”

“ If clutch release lever has more than 1⁄4–inch free play at end of cable, turn adjusting screw to the right (clockwise) to decrease amount of free play. Tighten lock nut after correct adjustment is obtained. Replace inspection hole cover. CAUTION: If end of clutch release lever has no free play as explained above, clutch will not hold when fully engaged. If too much free play is allowed, clutch will drag when disengaged; consequently, transmission gears will shift hard, clash, and eventually become damaged.
RA PD 310223
Figure 26—Adjusting Clutch Spring Tension
d. ”

“ Fig. 41 gives the starting-handle in part section. The handle H is attached to a tube which terminates in a clutch, C. A powerful spring keeps C normally apart from a second clutch, C1, keyed to the engine shaft. When the driver wishes to start the engine he presses the handle towards the right, brings the clutches together, and turns the handle in a clockwise [Pg 95] direction. As soon as the engine begins to fire, the faces of the clutches slip over one another. ”