The carriage glides easily forward upon a rod at the back of the machine, supported from the frame by ordinary standards. At the front center, the carriage is supported by a small wheel of hardened steel. A yoke with steel collars connects the carriage to the traveling rack, and thus they move together, one space at a time, and just as fast as the dog passes from one rack to the other. The paper is fed into the machine from behind and passes between two rubber rollers which hold tt, firmly in place. The smaller of the two, the feed roll, is pressed firmly against the larger by means of feed springs, held in place by set-screws. This insures an even tension at both ends and causes the paper to feed straight. It also admits paper of any thickness and any number of sheets, as the set-screws make time apparatus adjustable. This is one of the most valuable recent improvements. There are two inter changeable rollers or platens, of different diameters, for each machine. These are adjusted, the one for single copy work and the other for manifolding.
The Remington .3fachine (Fig. 2).—The printing is produced in this machine by type bars rising, so that one set of type strikes at one common printing point, and another set of type strikes at adother common printing point, both of which are a trifle off the center of the basket. These bars are hung from the top plate of the machine. The type, however, are arranged in pairs upon the type bars, so that one key answers for two type, requiring, how ever, an auxiliary shift when any of the upper-case letters are required. This gives a smaller keyboard, there being but 40 keys, which obviously represent 76 characters, as two keys are used for shifting. being this arrangement gives a more compact keyboard. two separate strokes arc required to produce any of the upper-case letters. The stroke is made by levers fulcrumed at the back of the machine. This is an easy leverage, requiring a stroke. The carriage is a 7 x 01 in. frame, which rides upon three wheels, two being at the back and one in front. Those at the back are grooved to fit the back rail, while the one in front is flat and has a plain track. The platen, feed roll, and connecting gear are fitted to slide forward and back when a shift from one ease to the other is required. Two yoke blocks connect these to the shift rail, which is in front, This rail has a forward-and back movement correspond ing to that of the carriage. A strong spring holds it well forward, so that the printing surface of the platen remains directly over the lower-case type. To print an upper case character, the shift key is pressed, throwing the platen back, with the printing sur face directly over the upper case characters. In the Cali graph the platen is corru gated, giving a flat surface upon which the type strike, and the type faces are plain ; while in this machine the platen is round and type faces are concave. Two rub ber straps, which pass be neath the platen and around each end of the feed roll, hold it in place. By switching, the platen may be made to bold a constant upper-case printing position, and then the lower-case shift must be used to find lower-case characters. This is useful in tabulating work and in printing headings. The carriage is drawn from right to left by a coiled spring attached to it by a leather strap. A yoke with steel bushings joins the carriage to a rack which engages its teeth with a dog in such a manner that the movement is made one space at a time. Here, however, the rack is single and the dog double, being split. When the machine is at rest, the forward dog engages the rack teeth and is pressed forward against its spring until aligned with the rear dog. By a rocker-bar movement both dogs are swung forward at each stroke, and just far enough to free the forward dog, when its spring carries it back the distance of one tooth. As soon as the rocker bar, resuming its normal position, has carried the front dog through the next tooth, it is again sprung forward and the spacing is made.
A ratchet is attached to the shaft carrying the coiled spring, and so arranged that it gears only when the carriage travels from right to left. At the other end of this shaft is a cog, which engages the teeth of another cog turning a shaft at right angles to it, which carries the ribbon spool. Thus the ribbon is reeled as the spring gradually unwinds, and receives its power from that spring, thus lightening the touch. The intermediate shaft just mentioned has bearings at both sides of the machine and is geared the same at both ends. By means of a switch, either one can be put in gear, and when the ribbon has been wound about one spool, it can he reversed and wound about the other.
The Smith Premier (Fig. 3).—The impression of the type is made in this machine by
the same upward stroke as in those previously described, but the type bars are arranged in a different manner. They are hung on bearings, one half of them being supported above the plate, and the other half below. But instead of forming chords of the plate circle, as in the machines already described, the bear ings are secant lines to that circle, and the type bar proper is at the extreme inner bear ing. In making a strong, firm stroke, the type bar should be at right angles to its bearing, but from the position of the bearing this is obviously impossible, and so the bars arc bent in such shape that the line of the bar at its striking point has such a position relative to its bearing. The theory is that with the increased length of bearing, the alignment will be permanent. The rocker-bar movement is used throughout the ma chine. Connecting rods are attached to the. other end of the type-bar bearing, and thus the ends draw against each other when the bar is in opera tion, The key levers of this machine are entirely different from what have been described. Circular bars. 76 in number, and about an eighth of an inch iu diameter, reach from front to rear and below the keyboard. They have a bearing at each end, and work with a circular movement, A rocker-bar movement attaches the key stem to this bar, and the same kind of an arrangement is used for joining it to the connect ing rods. These rocker-bar levers are arranged in 12 banks, with those of a bank directly over each other. The keyboard consists of 76 characters, corresponding to the same number of rocker-bar levers and type. Its arrangement is quite different from either keyboard described. The capitals are arranged in three banks above, and the small letters below, where they are conveniently touched. The numerals are arranged at the sides, and the punctuation marks occupy the remaining spaces. The carriage moves upon ball bearings, which have an enclosed track of their own. This arrangement insures a steady, even motion. The platen is hung on an open bearing, and is so attached to another set of bearings above that it can be swung out of its true bearings forward, so as to expose to the operator's view the printing surface of the platen and any writing upon the paper. The feed roll is attached to the rear carriage rod, so as to admit of a swing motion, governed by springs which press it against the platen. By pressing the paper table forward the two are disengaged and the paper can bo easily removed. The carriage is attached to a coiled spring at the rear of the machine by a fine steel chain, and is carried from right to left by it. The spring is joined to a wheel which turns upon a shaft, reaching from front to rear as the side. Back of the spring wheel is a weight, hung on an eccentric which rises and drops as the wheel turns, thus striking a bell. It is ganged, as in all machines, to trip and strike at the end of each line of writing. The ribbon spool is hung loosely upon this (;-in. shaft, a spring holding it pressed against a spiral stop at the front of the machine. As the carriage is pressed back from left to right, the spring is wound up, the shaft is turned, and with it the spiral stop, which presses the spool along the shaft also.
The Yost Machine.—The Yost is the only machine of its class which does not use a ribbon ; a pad is used instead. This is a circular piece of felt, saturated with ink, which fits the circumference of the machine disk. When at rest the type bars stand in a vertical Position with the type faces resting on the pad. There is no attempt at alignment, as the type are forced to a common printing point by means of a perforated diaphragm, haying a flaring opening which draws to a center the size of the type shank. The type bars have what is known as the ‘• grasshopper motion," and are operated by levers of the first class. The action is a complicated one, three additional levers being necessary, one of the second class and two of the third.
The Fr•anblin.—This is a type-bar machine which prints with a downward stroke ; thns the writing is visible without any movement of the paper carriage. There is a direct connec tion between the levers and type bars, which arc cog-geared. Teeth at the end of levers of the first class engage similar teeth on the type bars, so that the bars are forced down by a rolling motion. The machine has two type on a bar, the upper-case letters being printed by means of an auxiliary shift. Type-bar guides force the type to print at a com mon point. There are 40 keys, which can be modified by the shift, printing 80 characters.
The machine has a circular keyboard, radiating from the common printing point. .