US3440344A - Telegraph selector - Google Patents

Description

April 1969 R. R. SMESSAERT 3,440,344

TELEGRAPH SELECTOR Filed Feb. 17, 1966 INVENTOR RAYMOND R. SMESSAERT BYK ATTOR EY United States Patent 3,440,344 TELEGRAPH SELECTOR Raymond R. Smessaert, Chicago, 111., assignor to Teletype Corporation, Skokie, 111., a corporation of Delaware Filed Feb. 17, 1966, Ser. No. 528,155 Int. Cl. H041 17/16 US. Cl. 17817.5 8 Claims ABSTRACT OF THE DISCLOSURE A telegraph selector mechanism for receiving characters comprised of bits including a plurality of selector members that are individually moved to selected positions in response to received bits and that are collectively restored to unselected positions at the start of each character and an auxiliary selector member for storing the condition of a bit received during restoration of the selector members and for transferring the condition of that bit to one of the selector members.

In automatic telegraph apparatus selectors are used to accept a telegraph character in serial form from a remote transmitting device and to transform the character into parallel form. Typically, these devices employ a plurality of selector elements which are individually set in either a marking or a spacing position depending on the nature of the bits comprising the received character and which are stripped to a spacing condition before the beginning of a subsequent character so that the subsequent character may be received. In recent years the telegraph industry has changed from a five-level code (five bits per character) to an eight-level code (eight bits per character) and has increased the speed of transmission from four characters per second to fifteen characters per second. As a result of these changes it has become necessary to modify telegraph selectors so that the function of stripping the previously set selector members does not interfere with the receipt of a subsequent character.

Accordingly, an object of this invention is to improve the reliability of telegraph selectors.

Another object of this invention is to provide a telegraph selector capable of high speed operation.

A further object of this invention is to provide a mechanism for assuring that the stripping of previously set selector members will not interfere with the setting of the selector members in accordance with a subsequently received character.

In the preferred embodiment of the invention these and other objects are achieved by providing an auxiliary selector member positioned adjacent the regular selector member which is individual to and which is selected by the first intelligence bit of characters received. While the regular selector members are being stripped so that they may receive a subsequent character, the auxiliary selector member detects and stores the nature of the first bit of the subsequent character. The auxiliary selector member transfers the nature of the first bit of the subsequent character to the regular selector member with which it is associated and is then stripped to an unseleced position so that it is ready to respond to the first bit of the next character received.

A more complete understanding of the invention may be had by referring to the following detailed description when taken in conjunction with the drawing wherein:

FIG. 1 is a side view of a portion of a telegraph selector apparatus employing the present invention and showing the selector apparatus in an initial state of its cycle of operation;

3,440,344 Patented Apr. 22, 1969 FIG. 2 is a view similar to FIG. 1 showing the various components of the selector at a somewhat later state in the cycle of operation, and

FIG. 3 is a view similar to FIGS. 1 and 2 showing the various components of the selector in a still later state of the cycle of operation.

Referring now to the drawing wherein like reference numerals designate like parts throughout the several views there is shown a portion of a telegraph selector mechanism made in accordance with the teaching of United States Patent No. 2,595,745, granted to W. J. Zenner on May 6, 1952. Insofar as possible the reference numerals used therein are used herein to designate the same or similar parts.

Referring now to FIG. 1 there is shown a selector magnet 11 having an armature 12. In a typical telegraph application the selector magnet 11 is connected to a telegraph line. Telegraph signals are presented to the selector 11 over the telegraph line and the selector 11 moves its armature 12 upwardly in response to marking (current) signals and downwardly in response to spacing (no current) signals. The telegraph line which is connected to the selector magnet 11 is kept in a marking (current) state whenever no signals are being sent over the telegraph line. When it is desired to send a signal, a start bit, which is invariably a spacing (no current) bit, is sent and then a permutation combination of marking and spacing bits equal in number to the levels of the code being used are sent.

The reception of the start bit causes the armature 12 0f the selector magnet 11 to fall and, by means of a mechanism not shown herein but which is disclosed in the above-identified Zenner patent, this causes the tripping of a single revolution clutch (not shown). The tripping of the single revolution clutch connects a cam sleeve 26 to a constantly rotating shaft 27 for one cycle of revolution. Connection of the cam sleeve 26 to the constantly rotating shaft 27 causes a flutter cam (not shown) to be rotated through one revolution. The flutter cam has a plurality of indentations spaced substantially equally around its periphery and is used to free a marking lock lever 15 having an upstanding projection 19 for movement toward the selector magnet 11 under the action of a spring 22 during the interval assigned to each intelligence bit in the character received. The marking lock lever 15 will move to the right; that is, it will follow the indentation of the flutter cam if the armature 12 is in the upper or marking position during the time that indentation of the flutter cam is presented to the marking lock lever 15. If, however, the armature is in the lower or spacing position the upward projection 19 will engage the armature and will prevent the marking lock lever 15 from moving to the right, that is from following the indentation of the flutter cam, under the action of the spring 22.

Mounted on the marking lock lever 15 is a selector element control pin 64. The pin 64 moves to the right or remains in the leftward position in accordance with the movement of the marking lock lever 15 as determined by the position of the selector armature 12. A plurality of selector elements, each similar to a selector element 42 are pivotally mounted on a rod 66 and are each urged to rock clockwise around the rod 66 by a spring 67.

The selector elements each have a projection 68 which engages a camming surface 131 of a selector cam similar to selector cam 32 individual to each of the selector elements. The selector cams each have a high portion 132 and a low portion 133 formed in their camming surfaces 131 and are all attached to the cam sleeve 26. The low portion 133 of the individual cams are spaced circumferentially with respect to each other so that the projection 68 of one of the selector elements is presented to a low portion 133 of its respective selector cam during each bit of the character received. Thus, if all of the cams and all of the selector elements are considered as a unit, one of the cams and its individual selector element may be thought of as being assigned to each bit in the character received.

When the low portion 133 of the selector cam assigned to any individual bit is presented to the projection 68 of the selector element individual to that bit, the selector element is freed for movement clockwise about the shaft 66 under the action of its spring 67. The selector element will move to the right if the selector element control pin 64 on the marking lock lever has been moved to the right under the action of spring 22 as controlled by the flutter cam and the selector magnet armature 12. If, however, the marking lock lever is prevented from movement to the right by the selector magnet armature 12 being in the lower or spacing position, the pin 64 prevents the selector element from following the camming surface 131 of the selector cam.

Mounted just above and to the left of the selector elements are a plurality of selector members sometimes referred to as push levers, each similar to selector member 72. The selector members are mounted for oscillation and lateral movement on a rod 137 and are urged to rock clockwise and to move to the right with respect to the rod 137 by individual springs 76 attached to each of the selector members. In their normal position the selector members ride on a surface 134 of the selector elements. If, during the portion of the cycle of the selector mechanism assigned to a given intelligence bit the selector element individual to that bit is allowed to follow the low portion 133 of its selector cam by the movement of the marking lock lever 15 to the right, the selector member individual to the selector element and to the intelligence bit then being received fall off of the surface 134 and onto a shoulder 73 of the selector element with which it is associated. When the high portion 132 of the selector cam is again presented to the selector element the selector member is driven to the left against the action of the spring 76 and a surface 75 of the selector member may be used to actuate some portion of a telegraph mechanism which is controlled by the selector mechanism.

On the other hand, if, during the time that the low portion 133 of the selector cam individual to the bit being received is presented to the selector element individual to the bit the selector magnet armature 12 is in the spacing position, the marking lock lever is prevented from movement to the right and the pin 64 prevents movement of the selector element individual to the bit being received to the right. Thus, the selector member associated with the intelligence bit being received does not fall off the surface 134 and when the high portion of the selector cam is again presented to the selector element, the selector element simply remains in its leftward position and does not affect the selector member whatsoever.

After all of the bits of the character being received have been accepted by the selector magnet 11 and have caused appropriate movement or non-movement of the marking lock lever 15 so as to control the selection or non-selection of the selector members associated with each of the bits of the characters received, the selector members are simultaneously returned to their first position, that is, to the position wherein they rest on the surfaces 134 of the selector elements by the action of a stripper bail 142. The stripper bail 142 either at the end of the cycle of the operation of the selector assigned to a given character or at the beginning of the cycle of operation assigned to the next subsequent character, is rocked counterclockwise about the rod 137 by a stripper cam 36 which is mounted On and drawn by the cam sleeve 26. This action is effected by means of a cam follower 141 which rides upon the stripper cam 36 and which rocks the stripper bail 142 whenever the high portion 38 of the cam 36 is presented to the cam follower 141. After the selector members 72 are stripped by the stripper bail 142, the selector member is in position to receive a subsequent character over the telegraph line. A more complete and detailed understanding of the construction and function of the parts just described may be had by referring to the above-mentioned Zenner patent.

The device shown in the accompanying drawing is a modification of the selector mechanism shown in Zenner Patent No. 2,595,745 which allows that device to operate at extremely high speeds. In FIG. 1 the device is shown in a position wherein a selected regular or normal selector member 72 assigned to the first intelligence bit of characters received is resting on the shoulder 73 of its associated selector element 42 and has been driven to the left by the presentation of the high portion 132 of the associated selector cam 32 to the projection 68 of the selector element 42. The timing of the device shown in the drawing is such that the stripping of the selector member 72 from the shoulder 73 of the selector element 42 occurs simultaneously with the reception by the selector magnet 11 of the first intelligence bit of the next subsequent character. This is an example of an extreme case to which the present mechanism may be put; however, it should be understood that this device is capable of use in other timing situations so as to prevent any interference of the stripping operation with the selection of the first intelligence bit in the next subsequent character.

Referring now to FIG. 2 there is shown the mechanism shown in FIG. 1 at a somewhat later state in the cycle of operation. The low portion 133 is shown presented to the projection 68 of the selector element 42 and the high portion 38 of the stripper cam 36 is shown presented to the cam follower 141. The presentation of the high portion 38 to the cam follower 141 causes the stripper bail 142 to rock counterclockwise about the rod 137 thereby disengaging the previously set selector member 72 from the shoulder 73 of the selector element 42. The stripping of the selector member 72 does not, however, affect the positioning of an auxiliary seletcor member 172 which is mounted adjacent the selector lever 72 and which is associated with and controlled by the same selector element 42 which controls the regular selector member 72. Thus, if the selector element 42 moves to the right in response to the presentation of the low point 133 to the projection 68 and the movement of the marking lock lever 15 to the right, the auxiliary selector member 172 falls off of the shoulder 134 of the selector element 42 and comes to rest with its downwardly extending tab 173 positioned behind a vertical wall 74 of the selector element 42. The auxiliary selector 172 is driven to this position by the action of an auxiliary spring 176 which urges the auxiliary selector member to move to the right and clockwise about the rod 137. When the high portion of the selector cam 32 is presented to the projection 68 of the selector element 42, the auxiliary selector member 172 is driven to the left against the action of the spring 176 if the tab 173 has been positioned behind the 'vertical wall 74.

However, if the selector elemnet 42 does not move to the right when the low portion 133 of the selector cam 32 is presented to the selector element 42 due to the selector magnet armature 12 being in the lower or spacing position and thus blocking the upper portion 19 of the marking lock lever 15, the tab 173 cannot fall behind the vertical wall 74 of the selector element 42. Therefore, when the high portion 132 of the selector cam 32 is again presented to the projection 68, the selector element 42 merely remains in its leftward position and does not affect the auxiliary selector member 172 in any manner.

When the stripper bail 142 disengages the normal selector member 72 from the shoulder 73 of the selector element 42, the spring 76 would normally drive the regular selector member 72 to the right thus invariably placing the selector member 72 on the surface 134 of the selector element 42 and thereby causing the loss of the first intelligence bit of the character currently being received by the selector mechanism if the detection of the first intelligence bit in any way coincided with the operation of the stripper bail 142. This loss is, however, prevented by a tab 177 on the auxiliary selector member 172 which engages a surface 77 on the regular or normal selector lever 72 and prevents or inhibits movement thereof if the auxiliary selector member 172 is in its leftward position. Thus, if the auxiliary selector member 172 is driven leftwardly by the selector cam 32, the tab 177 is moved to the left and the regular selector lever 72 is prevented from rightward movement under the action of the spring 76 after it is stripped by the bail 142 through the interaction of the tab 177 on the auxiliary selector member 172 and the surface 77 on the normal selector member 72.

After the high portion 38 of the stripper cam 36 is moved out of engagement with the cam follower 141, the stripper bail 142 is moved downwardly and clockwise about the rod 137 as the cam follower 141 returns to engagement with the normal surface of the cam 36. The spring 76 thereupon causes the regular selector member 72 to rock clockwise about the rod 137 thereby coming into engagement with either the shoulder 73 or the surface 134 of the selector element 42 with which it is associated depending on the position of the tab 177. Thus, the normal selector member 72 is now in the position in which it would normally be in response to the first intelligence bit of the character received in spite of the fact that during receipt of the first bit the member 72 was being stripped from the position it assumed during the previous character by the stripper bail 142. Thus, the auxiliary selector member 172 has acted to record the nature of the first intelligence bit during the stripping of the regular selector member 72 and to transfer the nature of the first intelligence bit to the normal selector member 72 which is associated with the first intelligence bit thereby preventing loss of the first bit due to the stripping operation.

Referring now to FIG. 3 there is shown an auxiliary stripper cam 136 connected to the cam sleeve 26 and having a high portion 138 which engages a cam follower 241 to cause an auxiliary stripper bail 242 to move counterclockwise about the rod 137 thereby disengaging the tab 173 of the auxiliary selector member .172 from the vertical surface 74 of the selector element 42 if it is positioned behind the surface 74 and thus allowing the spring 176 to drive the auxiliary selector member 172 to the right and clockwise with respect to the rod 137. This re-engages the tab 173 with the surface 134 of the selector element 42 and thus repositions the auxiliary selector member 172 to record and store the nature of the first intelligence bit of a subsequent character while the regular selector member 72 is being stripped by the stripper bail 142.

From the foregoing it should be clear that by recording and storing the nature of the first bit of .a subsequent character in the auxiliary selector member 172 and by transferring the nature of the bit to the regular selector member 72 after the stripping operation is completed, the period of time available to effect the stripping operation is appreciably lengthened and the critical necessity of having the stripping operation completed by the time the detection of the first intelligence bit is started is dispensed with. Thus, the operation of the selector mechanism at high speed is made much more reliable.

What is claimed is:

1. In a telegraph selector having selector elements that permutatively impart a selected condition to associated selector members during receipt of a telegraphic code combination and move the selected selector members to a selected position after which the selector members are stripped to their unselected position to await receipt of a succeeding telegraphic code combination:

means for storing a succeeding selected condition of one of the selector element-s upon receipt of a succeeding telegraphic code combination during the stripping of the selected members;

means for imparting the succeeding selected condition to the selector member associated with said one selector element; and

means for clearing the stored information from the storing means after the succeeding selected condition has been imparted to the associated selector member.

2. In a telegraph selector having cam-operated, armature-blocked selector elements that latch and move associated normal selector members to a predetermined selective condition when unblocked by the armature:

means for unlatching the normal selector members from their associated selector elements after the normal selector members have been moved by the selector elements;

means associated with one of the normal selector members and its associated selector element for latching by the associated selector element when the unlatching means is unlatching the normal selector members and for causing its associated normal selector member to relatch with its associated selector element; and

auxiliary means for unlatching said associated means following relatching of the associated selector memher.

3. In a receiving selector for automatic telegraph apparatus having:

'an electromagnet responsive to incoming line signals;

a cyclically operated selector cam having a camming surface provided with a camming indentation;

a selector element;

means for urging the selector element to engage the camming surface and to follow the contour thereof including the indentation;

an armature lever selectively actuated by said electromagnet to block or unblock said element and upon unlocking to qualify said element to respond to the indentation of the camming surface;

a selector member operable by said element from a first selective condition to a second selective condition upon response of the element to the indentation; and

means for restoring the operated member to its first selective condition, the combination with said selector member of:

an auxiliary selector member associated with said element and operable thereby from a first selective condition to a second selective condition upon response of the element to its cam indentation for nullifying the restoration of the selector member.

4. The combination with said selector member according to claim 3 also including auxiliary means for restoring said auxiliary selector member to its first selector condition after it has nullified the restoration of the selector member.

5. The telegraph selector according to claim 1 wherein the means for storing a succeeding selected condition is an auxiliary selector member positioned adjacent the selector member associated with said one of the selector elements which determines the condition of said one of the selector elements while the selector member associated therewith is being stripped to its unselected position.

6. The telegraph selector according to claim 1 includmg:

a stripper cam; and

a stripper bail for operation by the stripper cam to strip the selector members to their unselected position; and wherein the means for clearing the stored information is an auxiliary stripper bail for operation to strip the storing means to an unselected position.

7. The telegraph selector according to claim 2 wherein the means associated with one of the normal selector members is an auxiliary selector member positioned adjacent said one of the selector members and having means for moving said one of the selector members to a selec tive condition while the unlatching means is unlatching said one of the selector members.

8. The telegraph selector according to claim 2 wherein the means for unlatching is a cam operated main stripper bail which simultaneously unlatches all of the normal selector members at a given point in the cycle of the selector and wherein the auxiliary unlatching means is a cam operated auxiliary stripper bail which is operated at a point in the cycle of operation of the selector after the given point to unlach the means associated with one of the normal selector members.

References Cited UNITED STATES PATENTS 2,623,118 12/1952 Salmon 178-175 2,667,628 1/1954 Chaveneaud 178-17.5 3,381,094 4/1968 Hackett et a1.

10 THOMAS A. ROBINSON, Primary Examiner.

US. Cl. X.R. 17833

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