US2861125A - griffith - Google Patents

Description

Nov. 18, 1958 R. G. GRIFFITH APPARATUS FOR TRANSLATING ELECTRICAL SIGNALS Filed May 2. 1955 INTO MECHANICAL PERMUTATION SETTINGS 2 Sheets-Sheet 1 1958 R G. GRIFFITH 2,86

APPARATUS F OR TANSLATING ELECTRICAL SIGNALS INTO MECHANICAL PERMUTATION SETTINGS Filed May 2, 1955 I 2 Sheets-Sheet 2 INVEA/TOR. Ran/.4; 0 6. G/e/F' 7-H 2,861,125 Patented Nov. 18, 1958 APPARATUS FOR TRANSLATING, Ecrmc L ggn Lgmro M CHANICAL. PERM T O Ronald G. Grifii h, MontrcaLQnebee, Cana a p a o May 2. 1.955;. S ria N 05.419 Claims priority, application Great Britain May s, 195.4.

5 Claims. c1. 1781-33),

The present invention relates to an apparatus for translating a coded electrical signal into a corresponding coded setting of a plurality of permutation members, to be used particularly with telegraph type printing apparatus.

Apparatus according'to the present invention fills, a need for equipment of this type which is capable of satisfactory operation even whent-he input signal has a relatively high degree of distortion. The manufacture of this equipment is greatly simplified because according to the invention one element requires a high degree of accuracy in its manufacture while agreater tolerance can be allowed in the other elements.

The present invention consists of a signal actuated member, a double-ended lever having a centrally located fulcrum and means initiated by the signal actuated memher to cause oscillatory sidewis'e displacement of the pivoted axis of the lever. One end of the lever, upon such sidewise displacement, is arranged to coact witha signal actuated member depending on its state of actuation. The other end of the lever is adapted to control the code setting of the permutation members.

According to a preferred; form of the invention the means for causing oscillatory sidewise of transverse displacement of the lever comprises a multipoint cam and a cam follower. A pivot shaft forms the fulcrum for the lever and the pivot shaft is connected to the cam follower. The cam follower is biased into coaction with a multipoint cam. The rotation of the cam is initiated by the signal actuated member. The means controlled by the lever for code setting the permutation members may consist of a plurality of pivoted latch mechanisms of which'the latching action is controlled by the lever. The latching action in turn controls the code setting of the permutation members.

In accordance with a preferred form of the invention a cam actuated bail is provided for pivoting the latched latching mechanisms in'one direction and a second cam operated bail is provided for pivoting the nnlatched latching mechanisms in the opposite direction. The direction of pivoting of the latching mechanisms controls the code setting of the permutation members.

A preferred embodiment of the invention is illustrated in the accompanying drawings in which:

Figure 1 is a pictorial view of a preferred embodiment of the invention;

Figure 2 is a partly sectional pictorial view of a modified mechanism for controlling the setting of the permutation members; and

Figure 3 is a graph illustrating the relative movement of various elements of the apparatus.

Figure 4 shows a modified arrangement of certain parts;

Referring to Figure 1 the selecting cam shaft 140 is in this preferred embodiment frictionally 'driven. The selecting cam shaft 140 is normally restrained in the normal rest condition by coaction between the cam shaft stop 16,1 and the detent 141 of the trip lever 142. The trip lever 142 is constantly urged to disengage the cam shaft stop, by the spring 143, but the disengagement is arrested by the trip pawl 144 by engagement of its detent 2. 160 with the stop 145. The stop 145 is rigidly attached to the frame of the apparatus. A signal recording magnet 270 is provided with windings 200 which are energized by the received coded electrical signals. Themagnet armature 201 is pivoted at 201a and is urged in a 7 counterclockwise direction by the spring 202. Energization of the magnet windings causes a degree of clockwise rotation of the armature 201, against the influence of the spring 202.

An extension 204 of the magnet armature 201 is arranged to coact with the pawl 144 in such a manner that when the pawl 144 is holding the selecting cam shaft against rotation and the magnet windings 200 become de-energized the extension 204 lifts the spring loaded pin 205. The pawl stop detent 160 is thus disengaged from the stop plate 145. The trip lever 142 is thus allowed a degree of counterclockwise revolution about its pivot 271 thereby disengaging the cam shaft stop 161 and the detent 141.

Thus the selecting earn shaft 140 is released for revolution. Owing to the cam face 206 of the pawl 144 the spring loading pin 205 is held out of interference with the armature extension 204, when the pawl 144 is in the release condition. The counterclockwise rotation of the armature 201 is limited by the stop 203. Toward the end of a one-half of one revolution the selecting cam shaft 140, by coaction of the reset cam 158 and the cam follower 159 of the trip lever 142, shifts the detent 160 of the pawl 144 to the left beyond the stop by rotating the trip lever 142 clockwise. At the same time the clockwise rotation of the trip lever 142 places the detent 141 in the path of the stop 161. Consequently, following the re-setting of the pawl 144 to engage the stop 145 under the influence of the spring 207, the selecting cam shaft 140 is arrested by the detent 141. The selecting carn shaft 140 thus rotates one-half of one revolution each time the spring loading pin 205 is lifted by the armature extension 204.

The pin 205 is spring loaded so that, should the magnet circuit remain de-energized for any reason, the selecting cam shaft will still be arrested after one-half of one revolution. In this case when the trip lever 142 is rotated clockwise the end of the pin 205 will strike the armature extension 204. The spring 272 will permit movement of the pawl 144 to the left while'pin 205 remains in contact with extension 204 so that the detent may still engage the stop plate 145.

The selecting cam shaft 140 carries a multipoint cam 208 which is arranged to oscillate a pivoted cam follower 209 in timed relationship with signal units, commonly referred to as mark and space, received by the windings 200. The cam follower 209 is pivoted at 20% and is biased into coaction with the cam 208 by a spring 214. A single double-ended transfer lever 210 has a pivot 213 mounted in a dependent lug 209a of the cam follower 209, and the left end of lever 210 is constantly urged into engagement with a stop 212 on lever 209 by a spring 211. It will be realised that the downward movementof the pivot 213 and transfer lever 210 is effected as a result of a positive drive from the cam 208 through the cam follower 209 and lug 209a, whilst its upward movement is effected by the spring 214. The oscillatory movement of the pivot 213, made up of these upward and downward movements, is, as can be seen, in a direction substantially perpendicular to the axis of the pivot213.

The selecting cam shaft 140 carries five selector cams 216-220. Each selector cam is arranged to control the movement of an associated selector pawl lever during the rotation of the cam shaft 140, forexarnple, the cam 216 and the selector pawl lever 221. As the cam 216 rotates. the pawl lever 221 is urged to move in a clockwise direction about a pivot shaft 273, under the influence of a spring 226, and this allows a pivoted permutation member in the form of a selector latch 228 to move forward (i. e. to the left as shown in Figure 1). On further rotation of the cam 216, the selector latch 228 is pushed back by the lever 221 to its normal position (as shown in Figure 1), provided it has not been operated upon by a striker 232 provided on the right end of transfer lever 210.

Thus the selector latch 228 is moved forward to lie under the striker 232 of the transfer lever 210, and is then pushed back to its normal rest position. Each of the latches, such as 228, is pivoted to a member or arm, such as 230, which is pivotally mounted on the common shaft 273 and urged in a clockwise direction by a spring, such as 231. The latch 228 is kept in engagement with the lever 221 by this spring 231 and by a spring 231a connecting the latch 228 with the arm 230. The five cams 216-220 are all identical but are displaced about the cam shaft 140 in such a way that the five latches are brought forward, one at a time, under the striker 232, and are each returned to their normal rest position unless they have been operated upon by striker 232.

These movements of the latches are in timed relationship 5 withthe signal units received by the winding 200.

When the magnet windings 200 are energized the armature extension 233 is placed for interference with the detent 234 of the transfer member 210, that is, extension 233 blocks downward movement of detent 234.

This position of the armature extension 233 will be referred to hereinafter as the mark condition. When the armature extension 233 is in themark condition and the pivot ca'rn follower 209 is oscillated the detent 234 of the transfer member 210 pivots about the end of armature extension 233 so that the transfer member 210 experiencesa degree of clockwise rotation about its pivot 213, This increases the stroke of striker extension 232 of the transfer member 210 to actuate any latches (such as latch 228) placed underneath it. The phase relationship of the fiutter cam 208 and the selector cams 216, 217, 218, 219, 220 is such that a latch is placed for coaction with the striker 232 just prior to the signal transfer member 210 reaching the position for coaction with the armature extension 233. This instant will be referred to hereinafter as the instant of selection. If the magnet windings 200 are de-energized at theinstant of selection then the detent234 will not engage the armature extension 233 as the armature 201 will be rotated counterclockwise out of the reach of the detent 234. Consequently the transfer member 210 does not receive a clockwise rotation about its pivot 213 and the latch (such as latch 228) placed under the striker at that instant is not unlatched because the striker does not move far enough to engage the latch. The selecting cam (such as cam 216) then withdraws this latch to the normal rest position in the latched condition.

When actuated by the striker 232, the selector latches such as latch 228 disengage their pawl levers (such as pawl lever 221). Consequently the pivoted lever 230 experiences a degree of clockwise rotation under the influence of spring 231. The pawl lever 221 then rides on the cam face 257 of the latch member 228 and causes this member to experience a degree of counterclockwise rotation about its pivot 227. The clockwise rotation of lever 230 is arrested by coaction of the latch stop 235 and the detent 236 of the mark transfer bail 247. The selector pawl lever 221 is then actuated by the earn 216 back to the normal rest position leaving the latch 228 disengaged. As the pawl lever 221 approaches its rest position it coacts with the cam face 257 so that the latch 228 experiences a further degree of counterclockwise rotation thus placing the detent 248 in position for actuation bv the detent 236 of the mark transfer bail 247 as described hereinafter; and also prevents further coaction with the striker 232.

After the cam shaft 140 has rotated one-half of one revolution each of the latch members will have been.

conditioned for coaction with the striker 232. Consequently the received signals are at this point recorded in the form of either latched or unlatched latch members.

The operating cam shaft 237 may be controlled by a conventional clutch mechanism which is arranged to be released when the cam shaft has about completed its cycle of operation. Alternatively, the operating cam shaft 237 could be integral with the selecting cam shaft 140. In this case the cams 238 and 239 would be carried by the cam: shaft 140. However, since this is a matter of design this alternative and the conventional clutch mechanism have been omitted for the sake of simplicity.

When the cam shaft 140 has about completed its cycle of operation the cam shaft 237 is released for one-half of one revolution, two cams 238 and 239 are rigidly attached to the operating cam shaft 237 and are arranged to effect the transfer of the selection set up on the latch members to corresponding code permutation members only one of which is shown at 3. The operation of the selecting cam shaft 237 causes the space transfer cradle 240 to experience a degree of anti-clockwise rotation about its pivot shaft 273, The space transfer cradle 240 coacts with all the selectorpawllevers at their extensions 241, 242, 243, 244 and 245 and causes them to have a predetermined degree of counterclockwise movement about their pivot cam shaft 273. Consequently all the latch members such as latch member 228 which are still in the latched condition (the condition shown in Figure 1) experience a degree of displacement in a counterclock= wise direction. As a result the pins (such as pin 246) causes the permutation members of the latched latches to move to the right. At the same time as cam 238 ope'rates, the cam239 operates therriark transfer cradle 247 causing it to have a predetermined degree of clock wise displacement about the pivot shaft 273. During this movement the transfer cradle extension 236 engages the detents 248 of any unlatched latches and imparts to the latch members, such as 228, and thesupporting levers, such as lever 230, a degree of clockwise rotation about the pivot shaft 273. As a result the pins such as pin 246 cause the permutation members associated with the unlatched latches to move to the left.

Relatching of a latch which has been unlatched during one cycle of operation takes place during the subsequent cycle (assuming no operation of the srtiker 232 takes place) as the lever, for example lever 228, moves to its forward position when permitted to do so by its cam, such as cam 216.

In the above manner, a series of signal units making up a signal character received during one half revolution of shaft 140 actuate the magnet armature 201, one after another, and are translated into a mechanical code setting which consists of a series of bars, for example bars 3, displaced in accordance with the signal character. It will be realised that this translation is to a large extent independent of any distortion of the signal units received, since such distortion, although it affects the position of the extension 233, is not usually sufficient, by itself, to cause this extension 233 to move from a point out of the path of movement of the detent 234 to a point in this path, or vice versa. Knife-edge selection is thus obtained, and is obtained, as can be seen, by causing oscillations of the pivot 213 of transfer lever 210. Such oscillations need to be accurate, but this entails, in practice, the accurate manufacture of only one part; the multi-point cam 208.

Figure 2 discloses a modified arrangement for effecting the displacement of the permutation bars in which the space and mark cradles are replaced by a single pivoted transfer member. In this modification the operation of unlatching the latched members such as latch member 249 shown on Figure 2 is exactly the same as the unlatching action of the latched members 228 of Figure 1. The cam shaft 237 can be integral with the cam shaft 140 or can be arranged to be released by the cam shaft 140 for a one-half of one revolution. In either case the cam shaft 237 is arranged to actuate the transfer cradle 251 after the latching action has been completed and the pivoted pawls such as pawl 230 have been returned to their normal and rest position. In other words, the cam shaft 237 is released for operation after the cam shaft 140 has completed its cycle of operation. The cam 250 rotates the transfer cradle 251 counterclockwise about the pivot 252 so that the pivot transfer member 253 moves towards the selector bar 254. If the latch 249 is in the latch condition (as shown in Figure 2) the transfer cradle 253 then coacts with the detent 256. As a result the transfer cradle 253 experiences a degree of counterclockwise rotation and its slot 274 coacts with the pin 275 to displace the bar 3 in a first direction to the right. If the latch 249 were unlatched then the pawl 230 would rotate clockwise under the influence of spring 276. This movement would be arrested by the stop 277. As a result when the transfer cradle 253 approaches the selector bar 254 the detent 255 causes the transfer cradle 253 to experience a degree of clockwise rotation. This results, by the coaction of the slot 274 and the pin 275, in the bar 3 being displaced in a second direction to the left.

Figure 3 illustrates the relative times of movement of the signal transfer member and the selecting pawl members. By way of example, three of the pawl members are illustrated on the graph (identified as SEL No. 1, SEL No. 2 and SEL No. 5). The remaining pawl members would have the same time of operation, merely differing in phase relationship to that of the other selecting pawl members. Degrees of rotation of the cam shaft 140 are illustrated along one axis, also time is shown in milliseconds based on the speed of operation of approximately 45 bauds. The second axis represents relative motion. The flutter curve illustrates the oscillation of the pivot 213 of the signal transfer lever 210. As can be seen from the graph, the period of oscillation is approximately 22 milliseconds while the time of movement of each pawl member is approximately 48 milliseconds. Therefore the code element selecting members 221 and 228 have more than twice the time of the unit signal element in which to operate. This means that one member (cam 208) of the apparatus has to operate sequentially within the unit signal element time spacing and even this member is moved in a sine type motion. Further, with this design of construction the instant of selection only varies between immediately following selections by the irregularities of manufacture of the flutter cam and by any variations to its angular velocity. As these variations can simply be reduced to a negligible factor the selecting mechanism provides a telegraph signal selecting mechanism capable of operating satisfactorily with high signal distortion placing of high degree of accuracy of manufacture on only one element and thereby providing maximum tolerance of manufacture in all the other elements.

The striker arm 232 is adapted to effect the unlatching operation of a latch such as latch 228 when a cam such as cam 216 has allowed its associated pawl, such as pawl 221, to rotate to a forward position but this action takes place at a time just after the most forward position of the pawl 221. Consequently on a second cycle of operation of the cam shaft 140 when the pawl 221 rotates through its most forward position the pawl 221 will latch into the latching position and in this way an unlatched latch may be relatched. Re-latching action of the appartus disclosed in Figure 2 is the same as the re-latching described above.

Referring to Figure 4 of the drawings, the mechanism for releasing the cam shaft 140 may be modified to the form shown in Figure 4. In this case the release lever 142 (of Figure l) is replaced by the two members 301 and 302. The lever 301 rotates about its pivot 303 to actuate the pawl 144 in a similar manner as described in relation to Figure l. The detent 304 of the lever 302 coacts with the cam shaft detent 161 in the same manner as the detents 141 and 161 of Figure 1. The pivot 305 for the lever 302 may be varied in its angular position with respect to the cam shaft 140. This variation provides for a different angular position of rest for the cam shaft 140. The extension 306 of the lever 301 couples the movement of the pawl 144 and the lever 301 with the lever 302. Thus the cam shaft may be released for operation in the same way as described in relation to Figure l. The extension 306 also couples the movement of the pin 307 caused by the reset cam 158 to the pawl 144 and thus the pawl 144 may be re-engaged with the stop plate 145 in the same manner as described in relation to Figure 1.

What I claim as my invention is:

1. A mechanical telegraph signal selecting mechanism comprising a single pivoted transfer lever having first and second arms on opposite sides of the pivot, driving means for oscillating said pivot of said lever in a direction substantially perpendicular to the pivotal axis of said pivot through a complete cycle of movement in each signal unit interval of each character cycle, said driving means acting with a positive drive to move said pivot in one direction of the oscillation, signal-responsive means comprising a single member controlled by received signal units having one nature to place said single member in a position in which it is engaged by said first arm of said lever during its positive drive movement and responding to signal units of another nature to move said single member into a position in which it is not engaged at all by said first arm of said lever, a plurality of pivoted members arranged to be moved in succession in timed relationship with received signal units into the path of movement of said second arm of said lever and being positioned to be engaged and operated upon by said second arm of said lever only when said transfer lever is rocked by engagement with said single member, whereby the positions of said pivoted members at the end of a cycle of signal character selecting operation depend on the nature of the corresponding units of the signal character.

2. A mechanism according to claim 1, and also comprising a plurality of pivotally mounted elements, each of said pivoted members being pivotally mounted on a corresponding one of said pivotally mounted elements so that movement of each of said pivoted members into and out of the path of movement of said second arm of said transfer lever is accompanied by rocking of the corresponding one of the said pivotally mounted elements.

3. A mechanism according to claim 2, each of said pivoted members being in the form of a latch which, at the end of the cycle of signal character selecting operation, is in a latched or unlatched position depending upon the nature of the corresponding unit of the signal character, said mechanism also comprising a first cam operated element arranged to act upon the latched members to cause turning of their pivotally mounted elements in one direction, a second cam operated element arranged to act upon the unlatched members to cause turning of their pivotally mounted elements in the opposite direction and a set of permutation members corresponding to the said pivoted members and moved into position by the turning movement of the said pivotally mounted elements.

4. A mechanism according to claim 1, said driving means comprising a cam follower and a multi-point cam controlling said follower, and means responsive to receipt of a signal character for releasing said driving means for operative movement through a complete cycle.

5. A mechanism according to claim 2, said driving means comprising a cam follower and a multi-point cam controlling said follower, and means responsive to receipt of a signal character for releasing said driving means for operative movement through a complete cycle.

References Cited in the file of this patent UNITED STATES PATENTS 2,675,425 Salmon Apr. 13, 1954

Images