US2911471A - Receiving system for telegraph signals - Google Patents

Description

Nov. 3, 1959 J. AUGUSTIN ETALY RECEIVING SYSTEM FOR TELEGRAPH SIGNALS Filed Jan. 7, 1957 MN vw QM mm QM mm a lillllllllllllll N w m A ATTORNEY United States Patent RECEIVING SYSTEM FOR TELEGRAPH SIGNALS Johann Augustin and Otto Holstein, Pforzheim, Germany,

assignors to International Standard Electric Corporation, New York, N.Y., a corporation of Delaware Application January 7, 1957, Serial No. 632,719 Claims priority, application Germany January 7, 1956 5 Claims. (Cl. 17826) This invention particularly relates to receiving selector mechanism for telegraph signals of the code combination type in which the telegraph signal elements arrive suc cessively.

According to the prior art receiving selector mechanisms are known in which upon the initial relapse of the armature of the receiving magnet the selector cam barrel is started in rotation and controls the advance of the so-called selecting sword members toward the armature of the receiving magnet whereby they are set, in dependency upon the position of the armature, into one of two possible positions. One such sword member is provided for each signal element of the telegraph code which is used. After the sword members have been thus set, they are moved in the opposite direction, i.e. away from the armature, to eifect the setting of other control-elements, e.g. the. selecting bars. Such an arrangement when used for the reception of the conventional start-stop type fiveunit code at a telegraph speed of 50 bands, operates as sword member toward an extension on the armature,

whereby this sword member is moved into its left-hand or right-hand position.

The change in position of the selecting sword member is determined by the position assumed by the armature at the moment in which the sword member is advanced toward it. If the first telegraph signal element, arriving after the start element, is a no-current or space element then the armature will remain dropped but if this element is of the current-on or mark type, then the armature, in the meantime, has been attracted again, thus causing the first selecting sword member to assume a position corresponding to the current condition of the first code signal element. After this first selecting sword member has again been withdrawn from the armature, the second selecting sword member, after a period of about 50 milliseconds, subsequently to the commencement of rotation of the selector cam barrel, will be advanced toward the extension on the armature of the receiving magnet. Accordingly, this selecting sword member, in the same manner as the first one, will be moved into a defined, predetermined position which, in turn, depends on the position of the armature and, consequently on the no current or current on condition of the second signal element. 7 4

In the same manner the third, fourth and fifth selecting sword members also are moved toward the armature of the receiving magnet and set to their respective positions. After all of the five signal elements have been received there will be effected the current on stop element, which is customary with the .start-stop type. fiveranged operating edges-or noses of the registering ele- 2,911,471 Patented Nov. 3, 1959 unit code, is received and causes the re-attraction of the armature.

Subsequently to the re-attraction of the armature when the selector cam barrel has completed a rotation its limiting stop arm will meet the armature, and be retained in this position until the arrival of the next character code signal.

Upon arrival of the new code signal the start element again causes the relapse of the armature of the receiving magnet, and the releasing of the selector cam barrel; in this way there is initiated the repeated process of receiving successive telegraph signal codes.

With respect to receiving systems of the aforementioned type, however, it has proved to be very disadvantageous that the armature has to be attracted by the magnet, and that the exploring process takes up too much time.

To avoid these drawbacks receiving systems have already been proposed in which the armature of the receiving magnet, in a predetermined rhythm and by the action of a mechanical drive, is advanced toward the magnet, and is retracted from its advanced position in the case of a no current or space signal element.

In such an arrangement in order to facilitate the setting of the sword members, the extension of the armature is not rigidly connected with. the armature, but is hinged to it in a resilient manner. Even when disregarding the extremely complicated construction of such types of receiving systems, it is impossible with them toachieve a substantially greater receiving margin and higher telegraph speeds.

Furthermore, other types of receiving systems are known, employing a'plurality of armatures which are successively advanced toward the receiving magnet. To eachof these armatures there is assigned an individual selecting sword member which, at a predetermined time position, is moved toward its associated armature, and thereby assumes a position determined by the nature of the received code signal element.

By means of receiving systems of the last-mentioned kind it is rendered possible, at a telegraph speed of 50 bands, to receive telegraph signals in an unobjectionable withapparatus incorporating selecting sword members there are experienced very high accelerations, e.g. between the swordand armature-control levers, of up to 6-10 km./sec. For this reason a telegraph speed of 50 bands cannot be very much exceeded in such types of arrangements, since this would lead to a mechanical breakdown within a very short time.

In order to avoid such lever accelerations and, in the case of critical receiving conditions, to extend the receiving margin as far as possible into the range around i50%, and at the same time to ensure reliable reception also'in the event of a varying operating amperage, and to permit of substantially increasing the telegraph speed, it is proposed in accordance with the instant invention that the receiver control bush with levers and small levers registers or stores the elements of a signal combination mechanically in a register, e.g. consisting of slides, in such a way that for this registering process there are only required very slight forces and lever movements. The power-consuming setting of the selecting bars, how- 'ever, is taken over and carried out by a cam plate which,

at the end of the registering of the signal combination, via a lever, moves the exploring elements toward the set registering elements,thus, by the meeting of one of the ends of said exploring elements on to the oppositely arments, performing the simultaneous setting of the elements of a selecting mechanism in the course of one operation. Thereby, despite the increased printing speed, the receiver control bush moves the armature control lever at half or at the same speed of rotation as beforewhich depends on the desired printing speed-toward the receiving magnet. In this way there is achieved a quieter operation of the lever arrangement at the smallest lever wear and at an increased printing or telegraph speed.

The objects and features of the invention will be better understood from the following detailed description of one embodiment read in conjunction with the accompanying drawings in which Fig. 1 is a diagrammatic representation of sufficient of the selector mechanism of a teleprinter for a proper understanding of the invention;

Fig. 2 is a view of the selector cam barrel, and

Fig. 3 illustrates the profiles of two of the cam disks.

Referring to Fig. 1 the reference numeral 14 represents a plurality of displaceable slide members which serve as code element storage means and the number of which corresponds to the number of signal elements in the type of telegraph code used. The slides 14 are urged in one direction by springs 15, and can be latched and unlatched by the action of pawls 11, under the control of levers 6, projecting teeth 8 on which are urged by the associated springs 7 with slight force against the peripheries of cam plates 27 on the selector cam barrel, so that they are capable of engaging in shallow depressions 29, provided that they are not prevented from doing so in this moment by an extension of armature 2. The armature 2, by the action of the teeth 28 of a star-shaped wheel 26 (see Figs. 2 and 3), is in known manner moved at a predetermined time position toward the magnet 1.

The armature 2 of the receiving magnet 1 is pivoted at point 3 and, at its front end 4, is provided with a detent 5, which when used with the standard five-unit code cooperates with five three-armed levers 6. By the action of a spring 9 the armature 2 is removed from the receiving magnet whenever this magnet is de-energized. Under the light forces of the five springs such as 7, the arms 10 of the five levers 6 are pressed with their teeth 8 against the edges of five cam disks 27 on the cam barrel and thereby actuate the pawls 11, which are pivoted at point 12, and the ends 13 of which cooperate with the five side members 14 for storing a signal combination. The slide members 14 are provided with depending projections 16 which abut against an arm of a lever 17, which is pivoted at point 18, and, in conjunction with a roller 35, is acted upon by a cam disk 20. The cam disk 20 takes over the power setting of the selecting bars under the control of the slide members 14 by actuating a lever 21, which is pivoted at point 22, and the end 23 of which is provided with the five T-shaped members 24, adapted to coact with the five slide members 14 of the storage means. It will be noted that all the levers involved in the control process only perform slight movements during the latching and the unlatching operations.

While there is only one armature 2, lever 17 and lever 21, five of the levers 6 and 11, slide members 14 and of the T-shaped members 24 are provided. The selector cam barrel (Figs. 2 and 3) carries a single star wheel 26 provided with teeth 28 (Figs. 2 and 3b) for actuating the armature 2 in the manner described heretobefore. In addition there are mounted on the cam barrel five cam disks 27 which are provided with diametrically disposed shallow depressions 29 and'29' (Figs. 2 and 3a) for causing the actuation of the levers 6 and two limiting stop arms 25. The cam barrel is driven through a friction clutch and is arrested after each cycle of operation by a stop arm 25. Such arrangements'are well-known and are described, for example, in US. Patents 2,505,008 issued April 25, 1950, and 2,329,580 issued September 14, 1943. The cam disks 27 are arranged on the cam barrel shaft in such manner that the depressions 29 and 29' on each half their circumference are staggered by a suitable amount with respect to one another. On each half of the circumference of the star wheel 26 there are formed six teeth 28. Five of these teeth are provided for controlling the response to the signal code elements, and one for the stop element. In this manner the cam barrel is capable of controlling the reception of a complete teleprinter code signal in half a rotation, that is, the cam barrel, in response to the start element of this signal, is released for this half rotation by the action of one limiting stop arm 25. During the next half rotation of the cam barrel, i.e. after its release is effected by the second limiting stop arm 25, the reception of a next successive teleprinter code signal is controlled. With an exploring time of 150 milliseconds, which is customary at present, for a teleprinter signal including the start-stop elements, the cam barrel thus only needs to rotate at half the customary speed, or if the presently customary speed of rotation of the cam barrel is employed the exploring of a signal may be performed in milliseconds. Hence with a receiver cam barrel rotating at half the speed customary nowadays there may be obtained a printing speed of 50 bands, and with a cam barrel rotating at the full speed customary at present there can be reached a printing speed of bauds. Taking into account the reduction of the exploring time of the levers involved in the receiving process for a teleprinter signal, the advantages resulting from the latching and the unlatching operations being carried out with as small as possible lever movement, and the increase of the operating speed being achieved without necessitating an increase in the customary speed of rotation of the cam barrel, it is possible in accordance with the invention to enlarge the receiving margin so that it approaches the theoretically possible margin of ':50%, at the same time maintaining silent operation of the lever mechanism and keeping the amount of wear to a minimum.

The mode of operation of the receiving system is as follows:

In the normal condition the armature 2 is continuously attracted by the closed-circuit current flowing through coil 1, and the cam barrel is arrested in known manner by the engagement of a limiting stop arm 25 controlled by the armature with a limiting stop on the cam barrel. Upon arrival of the first start element, the armature 2, under the action of spring 9, will drop off and by withdrawing the stop arm releases the cam barrel to perform half a rotation. The cam barrel then commences to rotate in the direction as indicated by the arrow at such speed that the teeth 28 on the star wheel 26 periodically advance the armature 2, in about the middle of the time positions of the telegraph signal elements following the start element, toward the receiving magnet 1. If the magnet, in the first element time position, is energized due to a mark condition, then the armature 2 will remain attracted. However, when the magnet is not energized in this particular time position due to a space condition, then the armature 2 will drop off with its detent edge 5 in front of the right hand of the levers 6 thus latching them. In the case of a mark element the armature 2 via its detent 5 will unlatch the lever 6, and the first lever 6, under the action of spring 7, will perform an instantaneous slight clockwise rotation, because its tooth 8 is now able to engage depression 29 provided at a suitable point on the periphery of the first cam disk 27. The remaining levers 6 are thereby unlatched but do not perform a movement, because they rest on the circumference of their respective cam disks 26. The rotation of the first lever 6 also causes the pawl 11 to rotate slightly in an anti-clockwise direction thereby unlatching the associated slide member 14 which, under the influence of spring 15, moves with its limiting stop 16 to the right. In this manner the first mark element of the telegraph signal is fed into the storage means. In about the middle of the next following telegraph signal element the armature 2, by the action of the next tooth 28 of the star wheel 27, is again moved toward the receiving magnet. If in this case the signal element is a no current one, the armature 2 will drop off and will latch the levers 6 by means of its detent 5. Now the second lever 6 is incapable of moving. The pawls 11 and their associated slide members 14 likewise will remain in their left-half positions. In this manner the second or space element of the signal is registered in the storage means. The above described processes will be repeated for the third, fourth and fifth element of the telegraph signal, depending on whether they are mark or space elements.

After the five elements forming the character code have been registered or stored in this manner, during which the cam barrel is only loaded with slight forces by levers 6 and the light springs 7, the armatureat a suitable time positionduring the stop element and by the action of the sixth tooth 28 on the star wheel 26 is advanced toward the receiving magnet 1, and since the stop element is a current-on element, the armature remains against the magnet. In this time position, due to a suitable dimensioning of the driving gears, a limiting stop arm 25 on the cam barrel (Fig. 2) in well-known manner engages -a limiting stop and the cam barrel is arrested until the next telegraph signal arrives. Upon arrival of such a next telegraph signal the operation is repeated in the manner as described hereinbefore, with the exception that the teeth 8 of the levers 6 drop into the respective depressions 29' on the other halves of the respective cam disks 27.

After a slide member 14, which is associated with the last element of a telegraph signal, has moved in accordance with e.g. mark element, that is, after all elements of a telegraph signal have been stored in the slide members 14, the cam disk 20 now takes over the powerrequiring or power-consuming setting of the elements 38 of the selecting bars under the control of the slide members 14 which have been set with only slight forces. This is accomplished in such a way that, subsequently to the storage of a signal combination, the lever 21 is turned clockwise by the action of the cam disk 20, because shortly after the storage of a signal combination, by means of a further cam on the selector cam barrel, the cam disk 20 is released for performing one rotation. The further cam is not shown but such arrangements are wellknown in the art and are described, for example, in US. Patent 2,329,580 previously referred to. By means of the clockwise rotary movement of the lever 21 about the point 22 the exploring members 24 are moved toward their respective slide members 14. Thus their depending end 39 or 40 engages a projection on the right or lefthand side of the edge of the respective slide member 14 and is rocked about the point 37 in one direction or the other dependent upon the setting of the slide member.

In this manner the selecting elements 38 are correspond ingly displaced to actuate printing or perforating mechanism of any suitable and known type. After the operating tooth 31 of the cam disk 20 has moved past the roller 32 of the lever 21, this lever 21 is returned to normal by the action of spring 33. Immediately thereafter a further tooth 34 engages the roller 35 on a lever 17, which performs an anti-clockwise rotation. Thereby the end of one arm of the lever 17 engages the depending projections 16 of the slide members 14, which are moved toward the left and latched again by the pawls 11 in their normal positions. The process of restoring the slide members 14, which clears the storage means is terminated prior to the arrival of the first element of the next tele graph code signal. Hence the storage means is ready again to register the next, immediately following telegraph cotle signal.

While we have described above the principles of our inventions in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation to the scope of our invention as set forth in the objects thereof and in these accompanying claims.

What is claimed is:

1. Selector mechanism for telegraph receiving apparatus comprising a rotatable selector cam barrel, a receiving magnet, an armature for said magnet, a plurality of slide members, first lever means which under the control of said cam barrel and responsive to the attracted or relapsed condition of said receiving magnet armature is arranged to successively set said slide members according to the nature of the respective signal elements of a received character code, an individual exploring member for each slide member, selector means individual to each said exploring member and controlled by the movement thereof, a rotatable cam disk, and second lever means associated with said cam disk and said exploring members for simultaneously actuating said exploring members to explore the setting of all said slide members and thereby actuate said selector means during one operative cycle of said cam disk.

2. Selector mechanism according to claim 1, wherein said first lever means comprises a plurality of levers one for each signal element and provided with projecting teeth, and said selector cam barrel comprises an equal plurality of selector cam disks formed around their peripheries with shallow depressions, light spring means being provided for urging said projecting teeth on said levers against the peripheries of the respective selector cam disks.

3. Selector mechanism accordin to claim 2, wherein each of said selector cam disks is provided on its periphhery with a pair of diametrically opposite shallow depressions whereby a code receiving cycle is performed during half a rotation of said cam barrel.

4. Selector mechanism according to claim 1, in which said selector cam barrel carries a star wheel the teeth of which during the rotation of said cam barrel cooperate with said magnet armature to move the latter towards said magnet at predetermined time intervals.

5. Selector mechanism according to claim 1, further comprising third lever means in cooperative relation with said rotatable cam disk and said slide members and arranged to restore the latter simultaneously to their normal position after said selector means has been actuated responsive to a received character code.

No references cited.

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