THE KEYBOARD

The linotype keyboard is power driven and mechanically operated, the operator merely touching the keybutton lightly to get a matrix. The keyboard and escapement mechanism consists of ninety-one mechanical units, or series of levers, escapements, and cams—one series for each key on the keyboard.

The keyboard consists of the frame; the keylevers, extending through the slots to the back of the keyboard frame; the keylever fulcrum rods, which are the pivot rods for the keylevers; the keybars, that groove into the rear end of the keylevers; the keybar banking bar, (fastened to the right- and left-hand keyboard posts), holding the keybars in place; and the keyboard locking bar. The various parts of the keyboard are held in their respective places by the keyboard frame.

Mounted on the top, at the rear of the keyboard, are the two cam yoke frames. The keyboard cam yoke frames contain the cams and the cam yokes, assembled; the cam yoke triggers; the cam stop strips; the hinge rods; the keyboard cam rubber roll shafts, with the pulleys or the gears and friction springs; and the rubber rolls, assembled. The frames are fastened to the keyboard posts by a screw at each end of the frame, which extends through the rubber roll shaft brackets. Both the frames are equipped with cover pans.

The keyboard action for releasing a matrix from the magazine is as follows: When the keybutton is depressed it lowers the outer end of the keylever, raising the back end. The keylever raises the keybar. The keybar raises the lower end of the trigger, causing the upper end to tilt. This allows the free end of the cam yoke to drop, causing the cam to engage the revolving rubber roll. The cam is revolved by the rubber roll, and as it reaches the high point it raises the free end of the cam yoke. This end of the cam yoke engages the keyrod and causes it to be raised. The keyrod operates the escapement mechanism in the magazine and releases the matrix.

Keyboard Parts

The keylevers extend through slots in the keyboard frame and are pivoted near their center by the fulcrum rods. The front end of the keylevers carry the keybuttons and the back ends fit into notches in the keybars.

The keybars are held in place on the back of the keyboard by the banking bar and the upper and lower keybar guides. The keybars have notches on the upper end into which the triggers set. Also there are notches into which the keylevers extend. These notches are cut at different points on each six keybars, to correspond with the point at which the keylever protrudes through the frame.

On the late model machines the keybars are made with notches so they will fit in any alternate position, each bar having three notches, any one of which will register with the keylever. In removing the bars for cleaning, always take them off in groups of six and keep them in order so that no difficulty will be experienced in replacing them. It is always better to replace each bar in its original place after having them off.

The keyboard locking bar extends across the back of the keyboard, just above a shoulder on the keybars. When this bar is forced down it prevents the keybar from being raised, thus locking the keyboard.

Keyboard Cams and Parts

The keyboard cams are small, brass, non-circular or eccentric pieces and are used to raise the cam yokes to operate the keyrods. The cams are pivoted and held in place in cam yokes. The outer end of the cam yokes are pivoted to the frame, while the inner ends are left free to move up or down in slots in the frame, directly underneath the keyrods.

When the cams are setting at normal, the free end of the yokes are supported by the pivoted triggers, which set directly beneath the yokes. When a trigger is moved by the keybar, it allows the free end of the yoke to drop, carrying the cam against the revolving rubber roll. The low part of the cam has small teeth cut in it, so when it drops on the revolving rubber roll, it is caused to turn. When the high part of the revolving cam is on the rubber roll, the free end of the cam yoke is raised to its highest point, raising the keyrod.

There are ninety-one cams and yokes in a keyboard. In order to get the cams in the smallest possible space, forty-five of them are located in the front frame, and forty-six in the back frame. The cam on the right-hand end of the back row is used to operate the spaceband lever.

A stop strip is fastened by means of six screws to each cam frame in such a manner that the small cross pins in the revolving cams come in contact with small pins which extend downward, stopping the cams after their revolution and holding them in normal position. The front strip has forty-five teeth and the rear strip has forty-six teeth; therefore they are not interchangeable. The strip should be located so the teeth do not bind the sides of the cams.

The top row of keys on the keyboard operate the cams in the back frame, the keys in the second row operate the cams in the front frame, the third in the back, etc., alternating for each row, so when tracing keyboard troubles it is known in which frame an offending cam will be found.

Several types of cam yokes have been manufactured for the various models of machines. Some are made of brass, others are stamped out of steel, while still another kind is milled out of a solid piece of steel. Different methods of fastening the pivoted end of the yoke have also been used. The older models were held by a pivot wire which ran through the yoke. The later models, however, have spring bars which set just above the pivoted end of the yoke, the yoke being hooked on the hinge rod and held down by a spring and plunger directly above the yoke, in the bar. This spring and plunger takes the strain off the yoke and keyrod when in an unusually heavy pull, and prevents damage to the rubber rolls.

On the top of the spring bar is an adjusting screw bushing through which the plunger projects. This plunger is forced against the top of the cam yoke by a spring. As the free end of the cam yoke raises, the spring must be strong enough to hold the pivoted end of the yoke from raising more than enough to give the full stroke of the keyrod. If something prevents the free movement of the escapement, the strain would come to the pivoted end of the yoke, forcing the plunger up, thus releasing the keyrod, cam, or rubber roll of undue strain. If this spring becomes weak, it will allow the pivoted end of the yoke to raise too high, thus lessening the up stroke of the keyrod. This shortened stroke of the keyrod does not permit the full stroke operation of the escapement, and does not allow the matrix to drop.

A weak spring will sometimes cause the matrix to drop slowly, due to the lug of the matrix binding on the lower pawl. By using the adjusting bushing this trouble can be remedied. Be careful in adjusting the spring, because too much tension will cause the cam to cut the rubber roll.

On some models the spaceband cam is of a different shape or larger than the other cams. This is done to accomplish the timing of the dropping of the spacebands.

To remove a single cam from the frame, shut off the power of the machine, take off the cover pans, touch the keybutton of the desired cam, draw out the pivot wire on old models or release the latch and tilt the spring bar on new models, turn the rubber rolls by hand until the end of the cam yoke raises, then lift the yoke and cam out.

Keyboard Rubber Rolls

The rubber rolls are held on shafts which extend through the cam frame. The right end of the shafts run in bushings which are held in the cam frame by a screw extending through the cam frame bracket into the shaft bushing. Two kinds of rubber rolls may be obtained: corrugated and ground. The rolls must be kept free from oil at all times. About once each month they should be removed and washed with soap and water to remove all oil, and freshen the rubber. The rubber roll may be livened up by the use of course sandpaper, rubbing from end to end and turning the roll so it does not become flat. The roll should be washed after using the sandpaper to remove the small particles of rubber that may be adhering to the surface.

If the rubber rolls become worn until they are grooved where the cams operate on them, or if they become hard with long use, they should be replaced with new rubber. Good, live rubber rolls have much to do with quick, even response of the matrices.

A rubber roll that is in good shape with the exception of a groove or two, can be used by cutting out the worn parts and placing in a good piece of another roll and fitting it to the shaft. Save parts of old rubber rolls for this purpose. They at least may be valuable for emergency patching, until a new roll can be ordered from the factory.

The rubber roll shafts are driven by friction, so that if anything binds unduly the shaft will stop, preventing damage to the rubber.

To replace a rubber roll, remove the old roll, polish the shaft, using care to clean thoroughly. A new roll must fit tightly and if the shaft is not clean and smooth, it will be hard to force the new roll on. Place the shaft in an upright position, start the end of the roll through the pulley end of the shaft. Place your thumb or hand over the other end of the roll to hold in the air and push down on the roll until it is in position.

On the later models the shaft carries a collar, pin, and oil collar on each end. This assembly must be removed on one end before the roll can be removed. The collar is held to the shaft by a taper pin and the oil collar forced over the top of the pin and collar. This oil collar must be pried off before the pin can be driven out.

Keyboard Troubles

Many of the mechanical troubles will be found in the keyboard, such as continuous response or non-response of matrices.

The keylevers sometimes get gummy or sprung to one side and bind on the frame, causing a continuous response of matrices. Another cause for continuous response may often be traced to some foreign substance such as metal shavings or dirt getting between the keylever and the frame.

A large percentage of keyboard troubles can be traced to the keybars. Most continuous response trouble is due to dirty or sticking keybars. These bars have several points of contact with other parts, and frequently a very small particle of dirt or dust will prevent the proper return of the keybar after being raised. This will hold the trigger out from under the cam yoke, which will continue to revolve and cause more than one matrix to drop. This trouble can usually be remedied by blowing out all dust from around the keybars and then washing them with gasoline, using a squirt can or brush to apply the gasoline. Before applying the gasoline, it is best to place a pan or cloth beneath the keybars to catch the surplus gasoline.

Be very careful not to get any gasoline on the cams or rubber rolls, as it will cut the lubrication on the yoke pivot and soften the rubber roll. After washing the bars, blow the surplus gasoline off with an air hose or bellows. Keep the air from the keyboard cams as much as possible, as it has a tendency to dry the oil on the yoke pivot pins, causing slow moving cams.

Sometimes the trouble is above the keybar banking bar. In this case it will be necessary to remove the back cam frame to clean the bars above the banking bar.

Should the keyboard locking bar become loose it may drop down a trifle and, preventing free action of the keybars, make the keyboard touch heavy.

In addition to the continuous response caused by the keylever or keybar, sometimes a dirty and sticking trigger or the trigger hinge rod being bent will cause this trouble. If one of the pins in the stop strip or the cam becomes worn or broken, the cam will continue to revolve.

Some of the common troubles of non-response might be caused by the free end of the cam yoke being dirty or gummy, a rusty, gummy, or bent cam yoke hinge rod, not allowing the cam to drop. A dry cam pivot will often prevent the cam from turning. A hard or oily rubber roll will not cause the cam to turn, especially on a cold morning. A tooth on the stop strip being bent sideways might bind the cam. Something binding the rubber roll, not allowing it to revolve, stops all cam response. A dry cam pivot or a sluggish cam will cause transposition of letters.

To locate the cause of a non-response, first observe if the keyrod is moving. If it is, the trouble will probably be found in the magazine or magazine escapement. If the keyrod does not raise, look for the trouble in the keyboard.

Do not take the keyboard apart every time a few matrices fail to respond correctly. It is much quicker to correct the trouble with the individual parts that may be bothering. Always locate the cause of the trouble before attempting to correct it.