US20698A - Improved pantographic telegraph - Google Patents

Description

UNITED STATES PATENT OFFICE0 GIOVANNI OASELLI, OF FLORENCE, ITALY.

IlVl PROVED PANTOGRAPHIC TELEGRAPH.

Specification forming part of Letters Patent No. 20,695, dated June 29, 1858.

To all whom it may concern:

Be it known that I, GIOVANNI GAsELLI, of Florence, in the Kingdom of Italy, have invented new and useful Improvements in Electric Telegraphs, which improved telegraph I call the Iantographic Telegraph, of which the following is a specification.

The nature ot' my invention consists in the production and transmission with the greatest possible rapidity of facsimiles of writings and drawings by sending and receiving at the saine time several dispatches by a single wire, and without effecting any change in the arrangement ot' the telegraphic lines already in existence.

As one ot' the chief` advantages of my telegraph lies in the rapidity with which dispatches can be received and transmitted, I hasten to state that this rapidity can be increased, as we shall see later, in the ratio of the dimensions which it is proposed to give to the telegraphic machines.

The following is a full description, reference being had to the accompanying drawings.

A B O l), a cast-iron stand ot' a pyramidal form, supports a metallic pendulum, a b c d, of the length of one hundred and forty centimeters. It is suspended by a horizontal axis, ot' which the two extremities are cylindrical, and which restson four wheels of equal diameter. Figure III represents the cast-iron stand, seen laterally.

At the lower extremity of the pendulum there is fixed at right angles an electro-magnet, d', having the form of a rectangular parallelopiped, as is morevclearly seen in Fig. IV, as well as in Fig. V, representing the same pendulum where viewed laterally.

Two pieces, c c', thoroughly welded, are of forged iron, destined to serve as armature on the electro-magnet d. They are solidly fixed on the sides of the base ofthe stand A B C D, as is also seen in Fig. VIII, representing the plan of the machine.

Fig. VII represents an electro-magnetic apparatus, which I shall term interrupter of the line,77 and ot" which we shall presently see the action.

B is a voltaic pile ot' Bunsen, of whichthe circuit is formed by acopper wire. (Represented in the drawings by a dotted line.)

far as the point s, to which itis joined by a spiral wire, and after having traversed the mercury which is in the basin u', arrives at the screw-button No. 4 and returns to Bunsens pile B. The electric current of this pile having thus magnetized the piece of iron d', which is at the extremity of the pendulum, the latter is retained by the armature c, but it is unable to touchit, from its being covered with alayer of caoutchouc.

In order to interrupt the current of the pile B', which I shall call the local pile,77 there is employed (as we shall see) the current of the telegraphic line, proceeding from the battery D. Before examining the direction taken by the current of this battery, let us tix fora moment our attention on the other pieces of the telegraphic machine.

A stand of cast-iron, L L, supports two parallel cylinders, one,ff, is visible in the ,Iirst gure, and the position of the other,j"f, may be observed in Fig. VIII, which represents the ground plan ofthe machine. A horizontal metallic rod, o o, bent at right angles at c and if, and jointed at the point c', must in consequence follow the movements of the pendulum. It is supported by the vertical rod s a, in such a way that its extremity x traverses a straight horizontal line, while the pendulum oscillates and the point o describes the arcs ot' a circle. The other rod, o o', also traverses with its eX- tremity a horizontal line. Now, if we sup pose that the current of the electro-telegraphic battery D leaves the pole l we shall see that it arrives by means of the copper wire (repreA sented in the drawings by red lines at the knob or button No. 2 of the machine, Fig. l) and reaches the point a, where the said wire branches oft in lines. The one of these two branches which descends as far as the cylinder f f, which is isolated, can afford no passage to the current, which by the other branch will In proceeding to examine the direction to be conducted to the point2 at the cup a, filled with mercury. The electric current will pass from the mercury to a platina point attached to the spring m, which is pressed on by the small cylinder z, fixed on the lever u z. This current then traversing the mechanical interrupter t, it will come to the knob or button No. 8, and will arrive at the interrupter of the line, Fig. VII. Thence, after having passed along the electro-magnetic reels p', the same current will return to the machine by the knob or button No. 9, and it will touch the point u, where the metallic communication is again divided into two branches. That formed by the lever u s, having, as we shall presently see, no continuity, cannot afford a passage to the electricity 5 but the other branch conducts the current by the knob or button No. 1 to the wire by which the two stations are placed in communication.

As the instruments of the two stations are exactly equal in their construction, it follows that the current of the line arrives at the knob or button No. l, second ligure. It takes, in a contrary sense, in this second machine the same direction that it has taken in the other. It reaches a copper plate, p Z, which is plunged in a well, and returns by the earth to the battery D', Fig. I. This constant traversing of the electric current is accomplished in a fraction of time quite indistinguishable, whatever be the distance existing between the two stations. It is thus that when the pieces of the instrument will have the positions represented in the drawings the current of the line must traverse at the same time the reels ot the interrupter of the line, Fig. VII, and of' the one corresponding to it at the other station. The temporary magnetism produced by these reels in the iron cylinder, by which they are traversed, exerts its force at both stations on the levers w. The currents of the local piles B being thus interrupted, at the same time the pendulums will no longer be detained by the electro-magnets d', and both are set in motion to accomplish their oscillations in obedience to the terrestrial attraction. When the movement of the pendulums has commenced the platina points being no longer pressed down in the cups 'w y by the small cylinder z and by the small hammer u, (which follows the movement of the lever u s, in which they are tixed,) separated from the mercury, and thus at this part also the metallic communications of the piles B' D remain broken. As the sm all cylinder z' on arriving presses the spring m an instant before the oscillation of the pendulums has been completed, it closes again the circuit of the local pile B', and the electromagnet d' is attracted toward its armature e', from which it cannot be detached until the little hammers n have unclosed the circuit of the telegraphic line. Then the parallelopipedon of iron d', Figs. I and 1I, remaining both deprived of magnetism, will fall back toward the iron armatures e and e', which are on the other side. In this manner the oscillations of the pendulum ought to be continuous and synchronous. It will be entirely understood that this synchronism is not dependent on the velocity, which is naturally peculiar to the two pendulums set in motion by the terrestrial attraction, because if even one of the two should arrive from any cause whatsoever and complete its oscillation a moment before the other it ought to stop attached to its ar1nature,wait ing until the other pendulum should complete its movement to fall back with it at the same instant. It results from this arrangement that the local piles B', Figs. I and II, supply the force, keeping up the oscillating motions of the pendulums, and that the current of the line regulates the synchronism of movements.

Let us now proceed to examine the functions of the current of the line while the pendulums drawn by their own weight are removed i'rom the armatures e c'. They advance to the right or the left. K

We have already seen how, when the spring m is no longer pressed down by the small cylinder z, it rose, withdrawing the platina point from the mercury contained in the vase w. The current ot' the line has been thus interrupted on this side, but at the same moment. The steel point r, which is attached to the lever p, being freed by means of the pressure ot' the small cylinder m on the piece b2, has come to rest on the cylinderff, and grazes it in the direction of the oscillation otl the pendulum. Meanwhile the current of the line having arrived at the button or knob No. 1, and afterward at the point u, traverses the rods u' s and o' o' x' until it reaches the metallic point r. From this point the electric current passes by the cylinder ff to the copper wire y y', and having reached the point r r, being unable to pass by thelittle vase w, from which the platina point has been raised by means of the spring m, it continues its course to the button or knob No. 2 across the battery D', arrives at the copper plate p Z, plunged in the Well, and, passing through the earth to the other station, traverses equally the battery D', and enters by the button or knob No.2 the other telegraphic machine,where, after having followed, in an inverse sense, the same path already taken in the first machine, it comes out at the button or knob No. l and performs by the wire of the line the telegraphic circuit.

To render this description clearer we have hitherto supposed that the steel point touched immediately the cylinderff; but now we must remark that on this cylinder are placed certain sheets of paper, 7c 7c, which the said point 2 grazes in a straight line. The paper placed on the cylinder ff, Fig. I, must be silvered over or covered over with a very tine coating of tin or zinc. On this metallized paper there has been previously written, with common pen and ink, the dispatch of which a fac-simile is required at the other station. On the corresponding cylinder at the other station there is placed paper chemically prepared with cyanide of potassium. If the voltaic batteries were arranged in such a way that the point r' belonging to the second machine were electried positively bythe current of theline during the oscillations of the pendulum, this point would produce on the chemical paper p p a line of blue color parallel with the axis of the cylinder f j'. The oscillation of the pendulum being continual, the point 1 ought to go backward and forward by the same line on the chemical paper; but itis necessary to observe that the said cylinder is in communication with a special mechanism, t', which imparts to it a rotating motion about its own axis, so that at each oscillation of the pendulum the surface of the cylinder, and consequently of the paper placed on it, keeps constantly advancing in the direction of the arrow j', Fig. I. This mechanism consists, chiefly, in a disk of brass, fixed by its center on the continuation of the axis of the cylinder. Fig. Vl represents it seen laterally, and in front a lever, a b, grooved at i, terminates in a little plate of iron, b i". Asecond lever, s s', grooved in thefirst ath, rests with its extremity aon the periphery of the disk c1, and is kept there by the pressure of the spring m, Fig. Vl. By causing the lever a bto describe arcs around the center t in moving alternately to the right and left its extremity b, the disk d and the cylinder to which it is attached will acquire a rotating motion on their common axes in the direction of the arrow s. This motion is produced in the telegraphic machines by successive shocks inthe following manner: We have already seen how at the termination of even oscillations ofthe pendulum the circuit ofthe local pile B remains closed for a moment. While this happens a secondarycurrent is developed in the wire t b, which, by magnetizing the electro magnets, attracts the piece of welded iron b i', which, then, on the interruption ofthe current, is brought back to its primitive position by the antagonistic spring r. The same rotating motion of the cylinders and consequent unwinding of the paper is contemporaneous in the two corresponding machines. Supposing, now, that the ink with which the dispatch has been written be an imperfect conductor of electricity, (and common black ink has, in truth, this quality,) we can easily understand that whenever the point 1', in grazing the metallic paper pp, happens to touch the writing the current of thetelegraphicline will be interrupted, and, to speak more strictly, weakened, and as with every diminution ofthe force of the current the intensity ot'the color on the chemical paper placed at the other station will be also weakened, there will be seen on the latter a multitude ofpoints less colored, which, on a sheetof deeper ground, will be so arranged as to present the image ofthe writing or drawing intended to be reproduced. This image, however, will always be pale and with difficulty discernible, and if the original be not written in-a very large character no effect will be produced. This imperfection is owing to the fact that as these do not become immediately destroyed `by the interruption of the current, the chemical action of the iron point o",

the colored lines are prolonged more than is necessary and tendto fill up the intervals, which, by remaining blank, ought to form the telegraphic fac-simile.

In order to obtain a perfect specimen and true fac-simile of the original characters described in colored lines on white paper it was necessary, rst, to give to the electrical circuits an arrangement which there might be obtained an effect opposed to that which we have traced, and nd a way that the chemical action of the point 2 might remain instantaneously destroyed, not only by the interruption of the current of the line, but by the mere weakening of the same. I succeed in procuring this result by arranging the circuits ofthe voltaic pile in the manner which, for greater clearness, is drawn in Fig. X. A wire, de f g, connects in the usual way the poles of the voltaic battery a b. The line 7s is a second copper wire, which, united at f with the other wire, performs the partial circuit 7c b g ofthe galvanic element a Y What will happen in the wire k while the entire battery a b is in action? The electric current directed from the point g toward the opposite pole, d, is compelled, on its arrival at the point j", to divide. Part of it follows the wire k in the direction of the dark arrow. The other part goes from the point f to the pole d. The voltaicelement, however, a', having its own electric circuit, tends to transmit a portion of its own current by the same wire ic according to the direction or" the red arrow. Thus there will be two currents in an opposite direction in the same wire ic,- or, to speak with greater truth, there will only pass by this wire the difference of the currents themselves. The electro-motive force of the sole element a is inferior to that derived from the other elements united. The wire 7c will therefore have a surplus of current in the direction of the black arrow, especially it' the wire 7c be ot' such a nature as to offer a marked resistance to the passage ofthe electricity 5 but as often as the metallic circuit shall bc interrupted at g there will be an inversion ofthe current in the wire k, which will then freely be traversed by the contrary electricity derived from the element a'. In this way, as the circuit of the pile a will remain always closed, there can be pro'- du-ced at will an inversion of the current in the wire ir.

XVe shall now see how, by these combinations of the electric circuit, we can obtain from the pantographic telegraph-dispatches colored with the utmost exactness on a white ground. In Figs. I and II we see some lines ofa blue color, of which we have not hitherto spoken. The copper wire represented by these lilies is attached to the metallic arc 00', which is isolated, and cannot have any iniiuence in the electric operations ofthe machines, Fig. I, which we have hitherto described, but in Fig. Il we see that while the pendulum oscillates from left to right the small cylinder 002, fixed to the lever c a, grazes with its metallic part and establishes just such a system of electric communication in the telegraph analogous with that represented in Fig. X. In fact, the current of the line derived from the first machine reaches the second at the button or knob No. directs itself toward u in the lever u s', passes, by means of the small cylinder .002, to a mctallicarc, m rm, and thence to the knob No. 3, continues its course as far as the positive pole of the pile a', (which thus becomes placed in communication with the other pile, D', forming, along with it, a single voltaic battery,) and returns by the earth to the other station. The wire g/ is thus put in communication with the positive pole of the pile D and at the saine time with .the negative pole ofthe pile d. It thus arrives at the knob No. 2 of the machine, Fig. II, and the electric communication which is established continues by the wire 102 w' to, arrives at the cylinder ff, and at the iron point r, continues along the rods 0 s s u2 and comes to the point u2, where it is reconnected with the circuit of the whole battery, consisting of the piles a D. The wireQ,I `ig. I, is thus placed in the same conditions with the wire k, Fig. X, when the pendulum oscillates from left to right, and the direction of the current belonging to it will be immediately reversed at every interruption occurring in the current connecting the two stations. Now, as often as the iron point 1" shall becolne positively electrified the color will appear in the point of the chemical paper placed beneath it 5 and as the interruption of the current of the line and the consequent electrization of the iron point is repeated, as we have seen, at each point of the writing or original drawing touched by the metallic stylus r, Fig. I, it is evident that the colored point will represent on the chemical paper a facsimile of the original placed on the cylinder at the transmitting-station.

In hitherto describing the different operations of the pantograph we have considered only the effects derived from the oscillation of the pendulums when going from left to right. Iiet'us now examine what occurs in the contrary oscillationsthose from right to left.

When we attentively observe in both machines the small cylinder x2, lixed on the lever a c, we see that it, when the pendulum is in motion, will alternately graze the upper and lower surface of the arc n fn, which is formed by an elastic band of metal. In this way as the circuit ofthe pile a remains successively closed and opened the telegrapic machine Fig. II will transmit dispatches while the pendulum moves from left to right, and will receive them while performing the contrary motion. The same thing in an inverse order occurs in the machine Fig. I, so that while the latter transmits the former receives dispatches, and the reverse. In order better to understand how this happens we must observe the form and use of certain mechanism.

Fig. IX represents the pendulum a b c t separated from the machine with its appendages.

The cross-lever m j' is supported by means of a pivot at the pointf from the perpendicular lever ej", jointed in c. The length of the levers c f and c f has such proportions that while the pendulum oscillates, and, in consequence, j" f describes arcs around the centers c c, the extremities x of the cross-levers take a direction nearly approaching that of a straight line, and the space which it traverses is equal to that of the chords subtending the arcs themselves, which are of equal length. This system of levers in the pantograph is double, and we have x and fr', which traverse the space in a straight line. At .r and there are xed small levers p, having at their ends the needles that are to graze along the paper. Vhen the pendulum swings from left to right a small lever supported by a hasp is raised in such a way that the point does not touch the paper placed on the cylinder; but when the oscillation has been completed the same lever, freed from the hasp, falls, and by its own weight presses on the paper with its point at the same time the lever is raised up and caught in the hasp by means of the small cylinder. The two points act thus alternately, and their effects are produced separately on the two cylinders ot' each machine. If a chemical paper be placed on the second cylinder of the instrument Fig. I, and the metallic sheet on which the dispatch is written be laid on the corresponding cylinder of the machine Fig. II, a new telegraphic communication will be opened, and our machine can thus at the same time transmit and receive several dispatches.

To complete the present description of the I pantograph it remains to prove the truth of what we said in the commencement, viz., that the rapidity of the transmission of the dispatches augments in the ratio of the size of the telegraphie machine.

In the machine of which wehave here given the plan, the point a ofthe pendulum describes in a second an arc, of which the chord, equivalent to the space traversed on the paper by the point writing, is about sixty centimeters. Supposin g that the dimensions of the machines were quadrupled, the point writing a ought to traverse in two seconds a space of two hundred and forty centimeters. In this way the product of the telegraphic machine would be quadrupled in twice the time or double in any given time. It is not necessary to add that this velocity would be greatly augmented if short-hand writing were employed in the transmission of dispatches. y Note I. The interruption of the circuit of voltaic pile B is produced by the interrupter, Fig. VII, when the current ofthe telegraphic line passes along the spirals on m. The lever rises and interrupts the circuits by means of the platina point t, which comes out of the mercury contained in little bowl y, and remains immersed in the alcohol, which is placed above the mercury itself. The point y remains always immersed in the mercury of the other Vase, s.

Note II. This small cylinder x" is thus composed: One half of copper and the other half iron, each having the form of a half-cylinder. Ihe surfaces of the two pieces in contact with each have the figure of a rectangular plane, dividing the cylinder into two equal parts, passing through its axis.

Note III. To construct a telegraphic machine of any size whatever the measure of the lever alb may be found by the following trigonometrical formula: If 2 be the length, ef: the half of the angle of the oscillation of the pendulum, ab e d u the cross-lever,f p the portion of the said line comprised between the jointing, j" f: w the unknown line f e', we shall have 00:00 sine 25k (1022L p)|a2 r.

In short, the advantages of my invention are rapidity of transmission ot' fac-similes of writings, drawings, or ciphers; secrecy of the correspondence; the transmitting different dispatches at the same time and with a single wire; the width of the dispatches in proportion to dimension of machinery; impossibility of error in transmission; continuity of work, as dispatches can be put on the cylinder without interrupting the movement; regularity in the movement of the machines kept up by terrestrial attraction, and by the continuous action of the telegraphic current.

I do not claim the general use of electricity for producing fac-similes upon chemically-prepared paper or other material; but

What l do claim as new, and desire to secure by Letters Patent, is-

1. The mode of rapidly transmitting the facsimiles of writings, drawings, ciphers, and arbitrary signs, in colored characters, upon ordinary white or chemically-prepared paper, substantially as described.

2. The mode of receiving and transmitting different dispatches at the same time and with a single wire, as described.

8. rIhe use of local piles with circuit always closed for the production of the characters on chemically-prepared paper, as described.

Paris on the 20th July, 1857.

GIOVANNI OASELLI.

Witnesses:

GEO. HU'r'roN, JNO. WALLER.

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