Those cams which are keyed to their shafts are accurately and rigidly set and the keyways so cut that there is slight chance of a mistake in returning a cam that has been removed.
The cams are sometimes forged with their shaft in a solid piece, while in other designs they are keyed in place, but whatever type is used, thecams and their shaft may be considered as integral with each other.
As has been stated, the cams on many motors are forged integral with their shafts, and there is consequently no possibility of the removal of one from the other.
Therefore such surfaces as the cams or valve stem rollers will demand less oil than will the bearings revolving at higher speed and carrying heavier loads.
If the motor is of the "L"-head type, all the cams will be placed on the one shaft.
Such valves may be operated by the same type of cams and cam shaft as those used to open the valves at the side.
The cam shaft to which the cams that operate the valves are attached is generally placed inside the crank case.
The bearings and camsof such a shaft are generally enclosed in oil and dustproof casing screwed to the top of the cylinders.
The valves are usually of the "poppet" variety, and are operated by cams which act at the ends of long levers having their fulcra on the opposite side of the valve, the stem of which latter is attached at an intermediate point.
The blast was secured by a fan, and the valve-gear was worked by camsinstead of eccentrics.
In the engine the steam enters at A, at the bottom of the case, and presses the cams apart.
The larger cams lift the levers and consequently the hinged cards, with the balls of different colors, and keep them lifted for some time, and during this period the smaller cams act upon the levers of the arms that hold the cups.
Each of the double cams which are provided with the toy is cut so that its operation will cause the figure to draw some well-known object.
The levers are kept in snug contact with the cams by a pair of spiral springs.
The pinion, which rotates in a horizontal plane, is provided with a couple of pins upon which is placed one of the sets of removable cams which accompany the toy.
The cams are double, being provided with two separate peripheral edges, and each edge is engaged by the short arm of a pair of levers, as shown in the engraving.
Yet they were affecting the cams and cogs and pulleys of young Mr. Perry's love affairs, and he felt the matter must be repaired, and put in running order.
Each of these camshas four or five points respectively, to suit the number of cylinders.
The mechanically operated valves were actuated by specially shaped cams, and were so arranged that only two cams were required for the set of eight valves.
Lubricate the embossed cams in the cam housing with a thin film of vaseline every fifty hours of actual running.
In this case not only the cams but also the gears used in driving the auxiliary shafts are forged integral.
The shaft is moved longitudinally in its bearings by means of an eccentric to put these cams into action.
It is made from a low carbon specially heat treated nickel forging, is first roughed out and drilled entire length; the cams are then formed, after which it is case hardened and ground to size.
The cam-shafts, cams and heads of the valve stems are all enclosed in oil-tight removable housings of cast aluminum.
This construction was afterwards changed to seven male camsand simple valve operating plunger and roller cam followers as shown at Fig.
Each valve is cam operated through a tappet, push rod and rocker arm, seven cams being used on a seven-cylinder engine and nine cams on the nine-cylinder.
The oil forced out of the ends of the cam-shaft bearings fills pockets under the cams and in the cam rocker levers.
Various forms of valve-lifting cams are shown at Fig.
In the event of the cams being loose, care should be taken to use new keys or taper pins, as the case may be.
Cam-shafts are usually simple members carried at the base of the cylinder in the engine case of Vee type motors by suitable bearings and having the cams employed to lift the valves attached at intervals.
The cams are then checked to see that they are separated by the proper degree of angularity.
How to Make Small Cams [Illustration: Channels of the Cams Formed with Strips of Brass Soldered to the Drum or Disk] In making models of machinery or toy machines, cams are very often required.
The washers beneath these heads are dished to give them elasticity and enable them to steady the cams without undue friction.
A method of producing cams without a lathe especially adopted for the purpose is shown in Figs.
The range of governor action, so far as the governor itself is concerned, is obviously a constant amount, because a certain amount of rise and fall of the governor balls will move the cams a given amount.
Suppose the work to be pushed through the rolls and to rest against the stop S, then when the cams C D meet it they will pull it through and reduce its thickness by compression towards the workman.
We have in these engine cams considered the steam supply and point of cut-off only, and it is obvious that a second and separate cam would be required to operate the exhaust valves.
The first usually employ fly ball governors which actuate cams or stops to trip the valves for the steam cylinders.
Similarly for the cutting of cams, an attachment fastened to the work table by three bolts is used, which cuts either cylinder or face cams of considerable size, and as conveniently as a machine built solely for cam cutting.
All that is necessary for cutting cylinder cams is to set the device with its spindle at a right angle to the machine spindle and move the supporting bracket so that its roller will meet the perimeter of the former cam.
The easiest way to take out the cams is to take off the back and front of the keyboard (Fig.
The keyboard cams should be taken out and thoroughly cleaned every six or eight months and oiled with a drop of clock oil on the journal pin.
Except where it is required to knit the needle rests on what may be termed the normal ledge, and it is only moved from this position when the camsreach it to make it knit.
A section of the dial or ribber, as it is often called, is shown crosswise at D with the cams at CB1.
At the same time the cams in the back bed are set for plain work and the needles there knit as usual at every course.
Each needle is free to prepare and complete its own loop, this being done in rapid succession as the camstraverse the heels or butts.
This is performed on the flat knitting machine by raising the cams for a shorter loop, and lowering them so as to draw a larger loop.
On the left of the plate are arranged the cams as in the front bed whilst the right-hand arrangement gives the set of the cams in the back.
This set of cams is placed on each bed right and left and the constituent parts are indicated as follows.
Cam B is shown in a dotted position raised so as to draw a shorter loop and the length of the loop can be varied according to the height of either knitting cams A or B within certain limits.
It will thus be seen that to make circular work we arrange the cams on the front bed so that they will knit in going to right but miss in going to left, whilst in the opposite bed the reverse holds good.
When the cams are rotating in one direction push-up cam PC1 operates the needles, and when the direction of knitting is reversed PC gives the needles their upward thrust to receive the yarn.
The old mortar remained, but the beating was done by iron-shod hammers, which were raised and released by cams on a shaft turned by water-power.
The beating was done by iron shod hammers which were raised and released by cams on a shaft turned by water power: this machine called a stamper is shown in the foreground of this picture.
The main difficulty in this machine was in the complex arrangement for forcing the collars upon the cams or wedges.
The valve is rotated by a rod lying on the band of the cylinder; upon this rod are two cams which perforate the band of the cylinder.
Though engines have been designed with devices for reversing by means of the cams operating the valves, the reversal of the screw's movement is generally effected through gears on the transmission apparatus.
This chamber is connected by pipes to the inlet valves of the cylinders, which are mechanically opened alternately by the action of special cams on the crank-shaft.
The cams constituting a drum are of heavy construction while the brushes are of fine copper several leaves thick.
These bear on cams constituting a drum, and they are usually made of several strips of copper.
Iron cams are used, the current being taken therefrom by six-leaf brushes, provided with stiffeners.
The movement imparted to the yoke by the camsis thus transmitted through the pinions and rock-shaft to the cross-slide.
The cams which operate the cross-slide are mounted on the right-hand end of drum E and actuate the yoke A (see Fig.
The arrangement of the cross-slide cams is shown in Fig.
Either one of these speeds can be automatically engaged at any time, by adjusting the cams N on disk D.
As will be seen, the different cams give different feeds.
On the periphery of disk D are also clamped dogs or cams N, which operate a horizontal swinging lever P connected by a link with vertical lever J, which controls the two spindle speeds with which the machine is provided.
Diagram of Cross-slide Cams and Feeding Mechanism] =Setting the Cross-slide Cam.
The cams for operating the turret slide are mounted upon the periphery of drum E.
The roll which engages the angular faces of these cams and imparts movement to the turret is carried by an intermediate slide which has rack teeth engaging a pinion on the square shaft C.
A bracket bolted up to the side of cylinder forms a bearing for one end of the side shaft, and also carries a spindle at its lower end on which the levers oscillate, transmitting the motion imparted to them by the cams to the valves.
Assuming that we have both cams finished to the proper shape and size, and the keyway cut in the side shaft, we can commence to mark off the position of keyway in the air cam.
An end view of the three camskeyed up on the side shaft is given in fig.
We may now consider the relative positions these two cams will occupy when keyed up on the side shaft.
The timing of the spark will be dealt with in the chapter on Cams and Valve Settings.
Having once thoroughly grasped the important part the cams play in the working of the engine, it will be an easy matter to adjust the valve settings, and to keep them adjusted correctly.
In small engines it is convenient to have the air and exhaust cams made in one casting, when one key only will be required.
Foster, who recently bought the Cams Hall estate in the county named, took it into his head to explore the mansion, and in doing so came across a number of old volumes which had been abandoned by the late proprietor.
It is because no machine that is built of human cogs and cams and levers and pulleys may ever work at one hundred per cent.
The big machine of modern industry must indeed have many odd camsand levers adjusted to it.
Above, and to one side of the "baster plate" was the shuttle race, through which the shuttle carrying the second thread was driven by two strikers, which were operated by two arms and cams located on the horizontal main shaft.
In the circular machine a circular series of vertical parallel needles slide in grooves in a cylinder, and are raised and lowered successively by an external rotating cylinder which has on the inner side cams that act upon the needles.
The valve h and the lever l are operated by cams mounted on the shaft m, and they are so set that the spark at i occurs when the chamber Q is full of the explosive mixture and the piston is at the top of the cylinder.
On that account the cams that move the valve h and the lever l are placed on a separate shaft, which is geared to the main shaft in the ratio of two to one; that is, the wheel K is twice the diameter of the wheel J.
The cams not only penetrate into the slots of the back posts, but project three digits beyond them.
The cams are of almost semicircular shape, of which the widest part is three palms and a digit wide, and they are a palm thick; they are distributed according to the four sides of the axle, on the upper, the lower and the two lateral sides.
The levers are of the same number as the bellows, and when depressed by the cams of the long axle they compress the bellows.
By this plan it is necessary that the current which has been diverted should fall down from a greater height upon the upper water-wheels, because these turn axles whose cams raise heavier stamps.
So that if the cams which depress the levers of the bellows turn from north to south, the cams of the stamps turn from south to north.
Thereupon it is immediately placed on the anvil, and repeatedly beaten by the large iron hammer that is raised by the cams of an axle turned by a water-wheel.
As it has two cams to depress each of the levers, it is necessary that it should have twenty-four cams, which project beyond it a foot and a palm and a digit.
The machine whose cams depress the lower lever is made as follows.
In like manner all the cams are inserted into the consecutive holes, for which reason it happens that the cams depress the levers of the bellows in rotation.
The key is adjustable and may be arranged for any station desired by means of the movable cams shown on the rear in Fig.
On the return of the dial, however, these cams engage the projection on the spring 15 in the opposite way and the passing of each cam forces this vertical spring into engagement with the ground spring.
When the dial is being pulled by the subscriber's finger, these cams engage the spring 15 in such a way as to move it away from the ground spring and no electrical contact is made.
A systematic, if not rigorous, approach to the design of gears and cams also is usually presented in such a course.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "cams" in a variety of sentences. We hope that you will now be able to make sentences using this word.
