US1798790A - Speed control for electrical typewriters - Google Patents

Description

March 31, 1931. w, c GOULD SPEED CONTROL FOR ELECTRICAL TYPEWRITERS 3 Sheets-Sheet 1 1 Filed May 14, 1930 'T WILLIAM C. GOULD March 31, 1931. w, GOULD 1,798,790

SPEED CONTROL FOR ELECTRICAL TYPEWRITERS Filed May 14, 1930 3 Sheets-Sheet 2 WILLIAM C. GOULD v O fil EN ro/e AT NE) March 31, 1931. w. c. GOULD SPEED CONTROL FOR ELECTRICAL TYPEWRITERS 3 Sheets-Shele'c 3 Filed May 14, 1930 WILLIAMjCBULD p TOR M w. M

ATT NE) ih nin titt il on filed liter it,

ohject invention is to provide o r sing he copi'tel letters ol? en c inted t pewriter to strilte the no then the lower cese iii-pen ting the greater con copi'tels end producing hel icehle to the class oil type-hm. is ectneted in brought into con o'venient ot the linger hey, at it constant speed, chines oi"- this the roller is engaging suriece oi the coinis vcl end, on contact with the roller, the described it seinirerolntion hetore coin rest. in others the surface oi the toughened end the coin is replaced is snhstentiolly e hoolr connected to e hor noechnnisni, this hook engoging e the roller and tollowing it onch'ed oil theliinit of its tro /eh purpose of my inventionthesetWo e cnniirel nt es eoch ol thcin octeits the type-hair th e torce which, in any niochine, directly with the I speed of the roller.

iting machines oi the cless referredit known and understood and are no or my present invention. ln order, howi. to niolre my invention clear it is necesto state that in these electrically operated es the roller or its equiveilent is driven hp at ell electric motor the speed of Which is controlled hr at rheostet. 'lhis rheostat is placed in perollel With the motor armature end hoth are connected in series With o choke coil or other tired resistance which may he one the field windings, hy Whichthe power input to the orinziture is controlled. Connected in this manner the rheostotactsos tt shunt tor the erinntnre end thus when the rheostzit is adjusted to its position of maximum resistance the power input into the motor is at its maximum end Vice Verse. its the motor is necessarily oi" the Variable speed type the speed of the motor end of the roller which it drives ore at their maximum With the rheostet it inexirnuni resistance and at their minitill I hy the operetor,

M139. Serial no. diiftfilllti.

rn'uni With the rheostzit et ininiinunrresieh once, while it the rheostot'he cutout coinpietely the motor Will receive the toil power input nah" h the fined insistence Will pose end Will occelerote to a speed greater then that which it Will ettoin With the rheostzit in ciron end inziiriinuni resistance invention in its simpler torin comprise 'nieens for increasing the resistiince oi the rheostet When the usual shitt key is octueted This increase in resistance, on there solid, increoses the speed. of the new tor and ot the roller and causes the upper case letters, Which ore brought into play by the usual oction of the shitt key, to he i0- tnn'ted more strongly then the lower case let-- ters. My invention also comprises means by which "the iflegree oi increese in resistance niey he adjusted hy the operator to secure co nplete evenness of impression between the two ceeesi it have thither toned that t more in th resistance ofi'credlo he so limited as to restroin the speed of the motor Within e lined maximum and that when so limited the acceleration of the motor is unduly sluggish, lit Will he understood that the shift key is used hy the operator. either to strilre e single capitol, es the initial letter oil at mine of a, sentence, or to Write o Word or at line in cepitsls, end-thot in the increase the rheostet innst letter case the ultimate speed of the motor iniusthe such as to give the correct Weight of impression Such being the case, it "Will he obvious that unless the motor occelerotes With extreme -mpidity o single capital Will in order to ovoid this diiliculty end to ohliti tein the desired rapid acceleration of the .rootor my invention further comprises means for breaking the rheostet circuit during an extremely brief period 0t" time, thus throwing into the motor at power input much higher than it would tolerate in continued operation and causing it to accelerate with the greatest possible rapidity, This initial breaker thus bringing the platen into a mechanism which need not be kick having been given to the motor the rheostat circuit is again formed, but at a point where the resistance is increased to a-des'ired degree, and the motor speed is thus brought to and held at a point which will produce the desired weight of impression in case a plurality of capitals are entire cycle of operations takes -place auto matically, in response to a single depression of the shift key, and with such rapidity that a single capital, such as an initial,-formed in the ordinary use of the machine by the most rapidoperator, will come up with the same force as the succeeding caps in a line of upper case letters. I

The spirit of my invention may best be understood by reference to the attached drawings and the following description thereof, in which I show an illustrative embodiment of my invention in connection with certain allied parts of a standard make of electrically operated typewriter. In these drawings, for the sake of clear distinction, I have indicated such parts as belong to the existing machine by means of index letters A, B etc., and the parts of my device by index numbers 1, 2 et seq. In these drawings Fig. 1 is an isometric projection of certain portions of the frame of the typewriter showing the osition of the shift key and the shift raif and of those parts of my device which are located in relation thereto;

Fig. 2 is a rear coils showing the contacts and the breaker in face;

Fig. 3 is a cross section through the rheostat coils and the low resistance contact and high and low resistance low resistance contact Fig. 4 is an end elevation of the rheostat subframe showing a portion of the low resistance contact breaking mechanism, and

Fig. 5 is a .wiring' diagram of the machine as modified from its original inclusion of my various, devices.

Referring toFig. 1, A-A, B and C1-C2 are portions of the typewriter frame, which may here be considered merely as position of certain moving parts. D is the shift cross barby which the carriage is raised in response to a depression of the shiftkey,

' osition to rerom the type ceive upper case impressions blocks.

The bar 1) is raised b an upward movement of the shift lever F which ispivoted at F, this movement in turn being produced by a partial forward rotation o the shift rocker lever G which is rigidly attached to the shift rocker-sha t nalled at I.I and is rocked by. means of further traced, to say that this mechanism it being sufficient depression of the shift key is responsive to a to be struck Thiswhich, for illustrative purpose,

elevation of the rheostat of the shift key L.

2 may form by thefixing the 141), while on depression 0 f H. This shaft is jour and that in so responding the lever G swings forward or in a right hand direction.

J is the shift key lever which ispivoted at K on a fixed part of the machine not shown. -LL are the two shift keys and M the shift lock key. N is the shift rocker rod by means of which a movement .of the right hand key is transmitted to the left hand bar. This rod is bent at each end into the form of a crank which is pivoted at 0-0 as shown, and when the shift key is depressed these cranks swing downwardly.

It will be understood that the above are parts of the existing typewritinglmachine to ply tain parts of my device, and that they are not of my invention.

Referring again to Fig. lever which is firmly attached to the end of the shift rocker rod N near the pivot point 0. \Vhen the shift key is depressedthe lower end of this lever moves backward or in a le hand direction, carrying with it the push rod 2 which is pivoted into the lower end of lever 1 as at 3. Y T

The box- 44 maybe of metal, fiber or other suitable material and is fastened inside the typewriterframe in any suitable manner as by means of screws passed through the lugs 55. A block 6, preferably of fiber or other insulating material, is attached at 7 -t0 the end of the push rod and is thus caused toreciprocate within the box as the push rod is .actuated by lever 1 in response to movement This block may be maintained in an upright bearing rod 8 and a compression spring 9 be. used to take up lost motion and return the block to its forward or retracted position. Through the upper part of the block I pass a-metalhc conducting stud lOto which I attach theterminal 11 of a conducting cable 12 13 which is preferably of metal but which must be insulated from the frame of the machine and therefore from the box if the latter is metallic. From each end of this strap I project inwardly the contact points 140,-- 14?), preferably adjustable as to length and so adjusted that when the block 6 is in the forward position the front end of the stud 10?) forms an electrical contact with the point f-the shift key and a responsive movement of block-6 to its rearward limit the stud 10a contacts with point 1411. These two points 14a'14b must be in electrical communication with each other and with the terminal 15 of the cable 16.-

By means of this device the circuit through the rheostat, which is a part ing machine, is broken and remade as will be disclosed.

Referring now to Figs. 2 and 3, separated coils of resistance wire wound on 1, 1 is a rocker position by means of a To one lug of the box I fasten a bent strap of the typewrittiU " position on the spring arm tact points 26, and the lower end of the .spring arm is connected 1ng through the coils P by breaking the circuit through bridge 18 and leaving bridge 19 in contact, the length of resistance wire through WhlCh the current flows is increased, and with it the resistance interposed between the terminals 12 and 17 Bridge 18 is based on a block 20 of fiber 2 or other insulating material which is'threaded to engage the long screw 21. This screw is restrained against end movement and is rotated by means of a thumb wheel 22, the bridge being thereby moved to right or left as preferred. 4

The bridge proper consists, first, of two contact arms 23 and 24, each of which bears on one coil and is made fast to the block. These arms are insulated from each other and are connected only by closing the make and break about to be described.

An outer arm of spring metal is in one piece and is permanently in contact at its upper end with the upper arm 23. At the lower end of arm 24 and in a corresponding 25 are placed conto an extension spring 27 which is adapted to be moved backward by a movable rod 28. On moving the rod'in this direction the contact points are separated,-while a contrary movement permits the spring 25 to bring them together and to complete a connection between the two coils P.

The means by which the contact points 26 are separated and the circuit normally existand the bridge 18 broken are indicated in parts in Figs. 1 to 4 inclusive. In Fig. l a stiff wire 29 is shown as passed through the u per end of lever G and as this lever swings f drward to raise the carriage in response to a depression of the shift key the Wire 29 is also pulled forward.

In Fig. 4, which is an end elevation of the resistance coil housing, the opposite end of this wire is shown as passing through the upper end of a crank 30 which is affixecl to an end of the rod 28. This rod is journalled in the coil housing as at 31-31 and is bent downwardly as at 32-32 to form a double crank. This crank moves backward in response to a pull on the wire 29 and thus flexes the spring 27 and separates the contact points 26. it is desirable to provide a screw nut 33 on the end of wire 29 to adjust the throw of and heat resisting cores and same form as block crank 28 and the time of separation of the contacts 26.

Bridge 19 .is basedv on a block 34 which should be of insulating material and of the 20. Block 34, however, need not necessarily be threaded to engage long screw 21 but may merely have a. hole through which the screw passes freely. The spring 35 is formed of one piece of metal and bears permanently on both coils, thus establishing a permanent electrical connection between them at a point farther from the terminals 12-17 than that at which bridge 18 connects them. 1 Therefore the resistance through the circuit 12-19-17 which comes into operation when bridge 18'is rendered inoperative by separating the contact points 6 -is greater than that of the circuit 1218-17 which is established when the points 26 are in contact.

The block 34 may be retained in any desired position merely by the tension of the spring 35 and the friction of its tips on the coils, being thus movable by hand if it is desired to increase or decrease the resistance of the circuit 121917. This simple method seems to be quite sufficient in practice, but if preferred the block may be passed through a slot formed in the cover plate and retained in a movably fixed position by clamps, or it may be threaded into the long screw so as to move in unison with block 20 and at a fixed distance therefrom when the screw 21 is revolved by the thumb wheel 22.

The electrical connections through which my device operates may be understood with reference to Fig. 5, which is strictly diagrammatic. The. motor which constitutes the prime mover in the illustrative typewriting machine is a high speed universal motor adapted to either direct or alternating current. This motor has the armature Q, the commutator the two field coils T1T2. The field T1 is connected in series with the armature and to the main power leads, while the field T2 is on a shunt which includes the armature windings and the rheostat. It is in this shunt that I place the make and break indicated at 4 in Fig. 1 and the rheostat bridges indicated at 18 and 19 in Fig. 2.

Tracing out the main circuit, the power lead 36 passes through a switch 37" to the brush S2, through the armature windings to the brush S1, through the lead 38 to the field T1 and thence to the power lead 39. The leads 36 and 39 are fused in the customary manner as at 40 and 4.1.

Tracing out the shunt circuit, the main lead '36 is connected by the lead 42 to the field coil T2 and by the lead 16 to the box 4 which, as, already described, has 14a and 14b. Either one of these points cs tablishes a connection through the studs 10 and the lead 12 to the lower rheostat coil,

R, the two brushes S1S2 and the contact points i thence through the bridge 18 s block 6 and during the movement of the rod 28 acts to I depression of the shift key but (or through the bridge 19 if the contacts in bridge 18 be separated, to the upper rheostat coil, thence through the lead 17 to the brush S1 and through the armature windings back to the lead 42 and the field coil T2.

The device'illu'strated functions in the following manner. When the shift key L is depressed the arm 1 swings rearwardly and imparts a corresponding movement to the rod 2 and the block 6, thus separating the contact points 10?) and 14b and breaking the shunt circuit. When the shift key is completely 4 depressed the block 6 has moved back to the limit of its travel and the contacting points 1011 and 1411 are brought together, thus remaking the shunt circuit through. the rheostat. An extremely brief but material interval of time elapses between the separation of the contacts 10?) and 14b and renewal of the contact between10a and 14a and during this time interval the shunt circuit is broken and the full power load is thrown on field coil I1 and the armature windings, thus giving the motor its maximum power input and causing it to accelerate with extreme rapidity. 1

Synchronously with the movement of the brief time interval mentioned certainmechanism, which is a part of the typewriting machine, causes the lever G to rotate to lift the carriage and bring the platen into position to receive a capital letter impression. This movement of the lever G imparts a similar movement to the wire 29 and the crank 30 and a reverse or backward movement to the bent rod 28. Thisbackward separate the contact points 26 and to break the circuit 12-1817, while .the circuit 12-1917 (which has a greater resistance) remains closed. It will thus be seen that, as there is a certain amount oflag to the movement of the arm G, due to the time required for the cam which actuates this arm to come into function, a depression of the shift key producesthree successive functions: first,- the breaking of the shunt circuit and the rapid acceleration of the motor; second, the open I ing of the contacts 26 and of the lower resistance circuit through the rheostat, and third, the remaking of the shunt circuit through the rheostat coils and the fixed bridge through a resistance greaterthan that previously existing, thus permitting the motor tooperate continuously, if desired, at a speedgreater than that revailing prior to the less-than the speed at which it would operate with the shunt circuit interrupted.

On the release of the shift key these func--. tions are reversed in order and the motor is decelerated, by the remaking of the lower resistance circuit through the rheostat, to the speed at which it should operate to give the the single without the interposition of breal l in the rheostat pression of said depression of said shift key for depression of said proper impression to the lower case letters.

While I have described my device as applied to a motor having a rheostat in a shunt around the armature and which therefore increases in speed when the shunt circuit is broken, I do not limit myself to this specific application It will be obvious that a reversal of the and of the bridge 18 would make my device applicable to a motor in which the rheostat was in series with the armature. In such case thefunction of the make and break 4 would. be to close or shunt around the rheostat, by which the motor would be suddenly accelerated, while the function of the crank rod 28 wouldbeto close a bridgeplaced across the rheostat coils at a position of less resistance than that atfunctions of the make and break and then to open a ground.

thus governing the speed of the motor at a rate higher than that at which it would revolve with this bridge open; l

It should also be understood t h at the portion of my device which comprises the two bridges 18 and 1 9 may be usefully applied the make and the ontacts 26' separate when the platen risesto the capital letter position and the motor accelerates because of the increased resistance thus thrown into the shunt circuit.

that which takes place when the shunt circuit is entirely broken and break and with the machine in the hands of a rapid operator the first one or two imressions in. a line of capitals would be somewhat lighter than succeeding impressions.

I claim as my invention:

1. In a typewriting machine having a shift key for bringing capital letters into function and-a power roller driven by a variable speed electric motor:- means responsive to a deshift key for accelerating said motor and saidpower roller when a capital letter is to be struck.

2. In a typewriting machine having a shift key" for bringing capital letters into funcspeed electric motor: means responsive to a accelerating capital letter is to be struck and for governin said speed at anincreased rate when said sh ft keyis held in a depressed position. a In a typewriting machine having a shi keyforbringing capital letters into function, a power rbller driven by a variable speed electriccmoto'r and a' rheostat adapted to vary the speed of saidmotori; means responsive to a s iftkey for so altering the resistance of said rheostat as to increase the speed of said motor when a capital letter is to be struck.

4. In a typewriting machine havinga circuit. In such case by the use of the make.

The acceleration, however, is not so rapid as iao shift key for bringing capital letters into function, a power roller driven by a variable speed electric motor and a rheostat adapted to vary the speed of said motor: means to place the rheostat out of function and thereby to rapidly accelerate said motor'; means to so alter the resistance of said rheostat as to govern the speed of said motor at 1 said means being responsive to a single depression of said shift key.

in a typewriting machine having a shift for bringing capital letters into function means responsive to a depression of said shift key for first opening and then closing said shunt circuit means for increasing the resistance of said rheostat when said shunt circuit is closed.

6. In a typewriting machine having a shift key for bringing capltal letters into function, a power roller driven by avariable speed electric motor and two parallel resistance units in shunt with the armature of said motor: a circuit breaker interposed in said shunt circuit and adapted to open said shunt circuit in response to a partial depression of said shift key and to close said shunt circuit in response to a further depression of said shift key; a bridge connecting said units at a point at relatively low resistance; a second ridge connecting said units at a point of, higher resistance, and means responsive to depression of said shift key for interrupting the circuit formed through first said bridge.

In witness that I claim the foregoing I have hereunto subscribed my nainethis 8th May, 1930.

WILLIAM C. GOULD.

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