US2025797A - High speed keying - Google Patents

Description

Dec. 31, 1935. l l v YQUNG 2,025,797

HIGH SPEED KEYING Filed Feb. 24, 1934 INVE NTOR LLOYD L. YOUNG ATTORNEY Patented Dec. 31, 1935 UNITED STATES PATENT OFFICE HIGH SPEED KEYING Application February 24, 1934, Serial No. 712,687

5 Claims.

This invention relates to transmitter keying means and more in particular to means cooperating with a signal perforated tape or signal marked tape to convert at high speed the perforations or marks on said tape into electrical energy, the intensity of which is representative of the signal markings or perforations on the tape.

General arrangements known heretofore in the prior are for keying a tape, comprise contact members which make and break in accordance with the markings on the tape. The tape generally includes a continuous row of uniformly spaced traction or center hole perforations in addition to the rows of signal perforations on each side of the center row. The tape is passed over or adjacent to keying members which cooperate with a Contact member to complete a circuit through the perforations or markings, thereby changing the signal markings or perforations into characteristic electrical energy.

In such arrangements considerable difficulty is encountered in providing contacts light enough to operate at high speed and yet sturdy enough to stand up under the voltages involved in keying the transmitter. Another disadvantage, one which is very serious, is that the speed at which the tape can be keyed is limited by the size and weight of the keying members and the rate at which they can be reversed in motion.

In my U. S. application No. 573,057, filed November 5, 1931, I disclose a high speed keying device which overcomes many disadvantages, including those mentioned above, inherent in such keying apparatus. The present invention is an improvement over the high speed keying device disclosed in said application.

The object of the present invention is to provide a new and improved high speed keying device in which no electrical contacts through which current flow are used. Another object of the present invention is to provide a new and improved high speed keying device in which a minimum number of moving parts are used. In this device the only parts which move, move through a very small distance.

Briefly the above objects and advantages are attained in accordance with the present invention by providing a magnetic circuit, the reluctance of which is varied at signal frequency. The circuit is free of contact making and braking elements. The keying device which. comprises a wheel having a plurality of metal paths on the periphery thereof which complete magnetic circuits during rotation of the wheel, `is sturdy in construction, though simple, and is -enclosed within a dustproof casing or cover which supports the incompleted magnetic circuits. The structure oi the wheel and of the casing and associated apparatus is such that it is practically impossible for the same to get out of order. The voltage variations produced by the successive completion of the magnetic circuit by the armatures controlled by perforations in the tape as the wheel rotates may be utilized in any manner for signalling purposes. Preferably said impulses are used by Way of thermionic relays to actuate a tripping circuit which keys a transmitter.

The novel features of my invention have been pointed out with particularity in the claims attached hereto. The nature of my invention and the operation of the same will be better understood from the following detailed description thereof and therefrom when read in connection with the attached drawing inV which the Figure 1 illustrates a high speed keying device arranged in accordance with my invention and connected to a thermionic relay which'actuates a tripping circuit to pro-duce current impulses of the desired shape and amplitude for signalling purposes;

While Figure 2 is an end view partly in section of the keying wheel of Figure l and is for the purpose of showing more clearly certain elements in the structure of the keying wheel.

Referring to the drawing, M is a ilanged wheel of non-magnetic material mounted on a shalt H which turns in bearings K, K. The bearings K, K may be supported in any manner desired. The wheel M carries a plurality of armatures C, C of soft magnetic iron of high permeability. The armatures C are elongated as shown and are spring biased toward the periphery of the wheel by means of springs N, N. The ends of the wheel M and the armatures C carried in the periphery Yof the wheel are covered by covers of non-magnetic material J, J. The covers J, J areV xed on the bearings K so that they do not rotate with the wheel M. Mounted in the edge or inner portion of each cover J, J is the soft iron core d of an electro-magnet. Each core d carries a winding d which is connected as shown toa source of alternating current of above audible frequency, say 10,000 cycles per second. Around the periphery at the middle of the face of the wheel M is a plurality of traction pins, a, for

pulling the tape T and aligning the tape with rer spect to the wheel M. The flanges or face of the wheel M are drilled with a multiplicity of holes to correspond to the signal perforations o r mark-Y ings on the transmitter tape. One end of the armatures C, C carries a pin, b, which protrudes as shown a short distance through the holes in the flanges of M. Normally the armature C is biased or forced by springs N against the outer periphery of the slots in which they are mounted so that the pins, b, protrude above the outer surface of the wheel. 'Ihe armatures C are pivoted as shown to rockabout the points O, O. The wheel M is built up around and on the shaft H and a ring integral with the shaft H and is cornposed of non-magnetic parts f, f; e, e, and M for ease of manufacture and assembly. The parts are keyed to the shaft by a key y as shown and may be bolted or fastened together by .machine screws not shown. In order to prevent the armatures from tipping and binding, suitable guides are milled in the rings e, ,f as shown more in detail in the end view at Figure 2 so as to give circumferential or side support to the armatures. The tape T is passed over the periphery of the wheel and when the wheel rotates either due to a driving force on the shaft H or to tension on the tape T, the tape is advanced over the wheel end dragging the wheel with it or being pulled by the wheel due to the traction effect of the pins, a, on the wheel or on the tape.

In setting forthvthe operation of the keying wheel it will first be assumed that the tape has signal perforations or dots. In this case there will be a perforation for each pin, b, on the armature C and the pins, b, will protrude through the perforations in the tape as the tape is drawn over the wheel. In other words, under these circumstances, there will be no movements of the armatures since they are normally biased towards the periphery of the wheel. `Now assume that the tape is entirely blank except for the perforations at the center for driving purposes through which pins, a, protrude. Under these circumstances, there will be no perforations for the pins, b, and as the tape passes over thewheel, each pin, b, will be depressed, causing each armature to rock about its pivot at O. When the pin is fully depressed by the tape the outer end of the armature will be raised until the top surface comes in contact, or substantially in contact, with the inner side rim of cover J. This places the metallic material C close to the pole faces of the core, d, which are just flush with the inside surface of the rim cover J. It is now apparent that i when an armature C passes under the pole faces of the electro-magnet, while the armature pin, b, is depressed by the tape T, the length of the air gap between the pole faces of the core, d, will be reduced to substantially zero. The reluctance of the magnetic path is now different than it was before the gap was so short.

Now assume that the tape T has normal signal perforations or marks thereon in addition to the traction perforations. Whenever a signal perforation is over the armature C adjacent the core, d, the pin, b, will extend through said perforation and C will not be rocked and will not shorten the air gap. When a space occurs in the tape, that is no marking, the pin of the armature C at that instant adjacent the magnet, d, will be depressed by the tape, thus shortening the air gap as that particular armature passes under the pole faces of the corresponding magnet core, d. As one set of perforations on the tape T gives the marking impulses and the other row of perforations or marks gives the space impulses it is evident thatV when, for instance, the tape has a perforation for one armature pin and not for the next adjacent pin, there will be a change in the reactance in the magneticV windings on the core, d,

when the air gap is decreased by the absence of the perforation. This change in reactance of the circuit produces a change in the voltage drop across the windings d thereon; This change in voltage may be utilized as excitation for any 5 signalling purposes. For example, this change in voltage may be utilized as excitation for a suitable thermionic tube relayand telegraphic signal impulses will be sent out when the tape is passed over the wheel. lo

Suitable provision for the proper biasing of the mark and space characters on the tape may be obtained by the proper position of the two magnets with respect to each other. The tape may be pulled by an outside means or power l5 may be applied to the shaft H so that the traction pins, a, on the wheel pull the tape. Suitable end thrust bearings may be provided in K to permit the wheel M to run true and free and the clearances between the cover J and the 20 wheel M may be so small as to reduce trouble from dust to a minimum. Small size and accessibility, together with the capacity for operation at high speeds without the introduction of retarding effects of inertia of parts, are obtainable 25 because a movement of each armature C can occur only once each revolution of the wheel M and the distance of travel of the armature is only about 51g of an inch and the time of travel is about equal to 1A; revolution of the'wheel. Al- 30 though the wheel might appear from thedrawing to be large, it may be small or large as desired to meet the particular requirements. In the drawing it is shown sufficiently large to clearly illustrate the relation of the parts in- 35 volved.v

The wheel of the present invention has numerous advantages not found in the high speed keying wheel of my prior application No. 573,057. For example, the magnetic circuit is consider- 49 ably shortened. The air gap in the circuit is shortened. The wheel and in particular the moving parts thereof are practically completely enclosed as far as the natural elements are concerned. This lengthens the operative life of the 45 wheel considerably. Moreover, in this wheel no dust can reach the moving parts to clog the same.

The windings d of the vmagnets may be energized in any manner. For example, they may 50 be energized by an alternating current source Il connected as shown with the windings. The current changes due to changes in the reactance of the windings d which are in turn due to changes in the reluctance of the magnetic circuits, which changes are trulycharacteristic of the signal perforations or markings on the tape, may be utllized in any manner for signalling purposes. For example, these voltage changes or current changes may be applied to the terminals of a co pair of resistances R connected as shown between the control grids of a pair of tubes Il). The control grids of these tubes may be maintained at the desired operating potential by source l2 connected as shown. The anodes of the tubes l0 65 may be connected together by way of resistances R1 and to a source of potential not shown. Points on the resistances R1 may be connected to a resistance R3 and may be conected by way of additional resistances I4 to the control grids of "0 a pair of tubes I6 connected in a tripping circuit. The anodes of tubes I6 are connected together as shown by resistances I 8 and to a source of' potential 20. The anode of each of the tubesV lr6 may be connected by resistance 22 to the 75 control grid of the other tube. This is to produce a tripping eifect in this circuit. By tripping effect it is meant that when current starts to flow in the anode circuit of one tube due to a biasing impulse on the control grid thereof, the drop of potential through the resistance I8 in the anode circuit of said tube will be trans- Initted by way of a resistance 22 to the control grid of the other tube to bias the same more negative so that less current will flow in the anode of said other tube. Of course, when less current ows in the anode of the said other tube there is a rise in the potential of the resistance I8 in the anode circuit of said tube, which rise is transferred by the resistance 22 to the control grid of the first tube to make the same more positive. The effect is accumulative so that if the control grid of one of the tubes I6 is biased more positive there is an instant switch of the current of the system to the anode circuit of said tube. This switching of current from one tube to the other may be utilized for marking purposes or to key a transmitter. The tripping circuit described above has been disclosed more in detail in Finch United States application No. 364,831, filed May 2l, 1929, and application No. 380,447, filed July 23, 1929, and has been claimed in said applications and per se forms no part of the present invention. The description of the tripping circuit is thought unnecessary at this point.

Having thus described my invention and the operation thereof, what I claim is:

l. A high speed keying device comprising, a rotatable shaft, a non-magnetic wheel on said shaft, a plurality of armatures pivotally mounted in said wheel and biased toward the periphery thereof, said armatures each having a pin normally extending through an opening in the face of said wheel, a tape guide on the periphery of said wheel whereby a perforated or marked tape may be passed over said wheel so that said pins may extend through the perforations or into the markings in said tape, and a xed magnet mounted adjacent the periphery of said wheel, said magnet having an air gap adjacent the path of rotation of said armatures in the periphery of said wheel.

2. A high speed keying device comprising, a rotatable shaft, a non-magnetic wheel on said shaft, a plurality of armatures pivotally mounted in said wheel, said armatures being spring biased and each having a pin normally extending through an opening in the face of said wheel, a tape guide on the periphery of said wheel whereby a perforated tape may be passed over said wheel so that said pins may extend through the perforations in said tape, a non-magnetic cover for said wheel, said cover being non-rotatably mounted relative to said wheel, and a magnet in said cover having an air gap adjacent' the path of rotation of said armatures in said wheel.

3. A high speed keying device comprising, a rotatable shaft, a non-magnetic wheel mounted on said shaft for rotation therewith, said wheel having a plurality of slots in its periphery,'said slots having an opening at one end extending through the periphery of said wheel, an armature pivotally mountedin each of said slots, said armatures having an extending portion at one end, springs biasing each of said armatures toward the outer periphery of said wheel so that said extending portion passes through said openings in said wheel, a magnetic circuit adjacent the periphery of said wheel, said magnetic circuit having an air gap adjacent the path of rotation of said armatures in said slots, and a tape guide on the periphery of said wheel, said tape having markings or perforations in'which the extending portions on said armatures may pass when a tape is pulled over said wheel, whereby said armatures are pivoted by the absence of a perforation or marking in said tape to close or shorten said air gap in said magnet to change the reluctance of said magnetic circuit.

4. A high speed keying device comprising, a rotatable shaft, a non-magnetic Wheel mounted on said shaft for rotation therewith, bearings for said shaft at each end of said wheel, said wheel having a plurality of slots in its periphery, each of said slots having an opening at one end extending through the periphery of said wheel, an armature pivotally mounted in each of said slots, said armatures having an extending portion at one end, springs biasing each of said armatures toward the outer periphery of said wheel so that the extending portions normally pass through said openings in said wheel, a wheel cover mounted on said bearings and extending over the periphery of said wheel, a magnetic circuit in each of said coverings, said magnetic circuit having an air gap adjacent the path of rotation of said armatures in said slots, and a tape guide on the periphery of said wheel, said tape .having markings in which the extending portions on said armatures may enter when a tape is pulled over said Wheel, whereby said armatures are pivoted by the absence of marking in said tape to close or shorten said air gap in said magnet to change the reluctance of said magnetic circuit.

5. A high speed keying device comprising, a rotatable shaft, a non-magnetic wheel on said shaft for rotation therewith, a plurality of armatures pivotally mounted in recesses in the outer periphery of each end of said wheel, each armature having a pin normally extending through an opening in the periphery of said wheel, a tape guide on the periphery of said wheel, said tape having signal perforations therein through which said pins may pass, a non-magnetic cover mounted on a bearing at each end of said wheel, said cover extending over said wheel, and a magnetic circuit including an air gap mounted in each of said covers, said air gap vbeing placed adjacent the path of rotation of said armatures, whereby vwhen said tape is passed over said Wheel and said armatures are rocked on their pivots due to the presence or absence of signal perforations in said tape, the air gap is lengthened and shortened. LLOYD L. YOUNG.

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