US3035765A - Word counter - Google Patents

Description

May 22, 1962 R. E. zx-:NNER ETAL 3,035,765

WORD COUNTER 3 Sheets-Sheet 1 Filed Jan. 16, 1958 INVENTORS @gewi/Mfr@ 3J: s'm/d May 22, 1962 A Filed Jan. 16, 1958 R. E. ZENNER ETAL WORD COUNTER 5 Sheets-Sheet 2 May 22, 1962 Filed Jan. 16, 1958 R. E. ZENNER ETAL 3,035,765

woRn COUNTER 5 Sheets-Sheet 3 /A/Pur cwwrsurva) United States Patent Otiice 3,035,765 Patented May 22, i962 3,035,765 WORD @GNTER Raymond E. Zenner, Park Ridge, and Howard E. Morris, Skokie, lil., assignors, by mesne assignments, to Victor Comptometer Corporation, Chicago, El., a corporation of Illinois Filed Ian. 16, 1958, Ser. No. 709,227 6 Claims. (Si. 23S- 92) This invention is concerned with counting apparatus, most particularly with a word counter such `as used in conjunction with teletypewriter apparatus and the like.

For various reasons it is often desirable to know the traiiic count for any given teletypewiiter machine or circuit or the like. As is well known to those skilled in the art, there is one letter transmitted for each band or time interval ion teletypewriter circuits. During each band or time interval there are transmitted one or more pulses, the number, duration, yand spacing of which determine the character that will be printed 4at the receiving station. It is possible to count the number of :time intervals during the time intelligence is being transmitted, and by assuming -a word to be comprised of an arbitrary number of time intervals, it is possible to utilize a counting device to ascertain the number of words carried overthe circuit. p f Y In prior word counters for use in conjunction with teletypewriter circuits, electromagnetic devices have simply vbeen connected directly into the line and have been actuated by the line current. This has certain inherent drawbacks. For one thing, the pulses of current on the line ideally are of a square wave or shape. Thus, the receiving device or machine is provided with sharp pulses which properly actuate the machine. Unfortunately, when electromagnetic devices lare connected into -the line the inductance thereof distorts the wave form to ya greater or lesser extent. It is quite possible for the wave form to be so distorted under some conditions as to prevent proper operation of the receiving machine, thus leading to a garbled message. Furthermore, the nominal line current when in full on condition is supposed to be twenty milliamperes (for a so-called twenty mil circuit), but may drop to as low vas fifteen milliamperes, thus leading to chattering or slow closing of contacts in an electromagnetic device. Conversely, when the circuit is in full oft condition, there is supposed to be no current whatsoever owing. However, there may be a leakage current of `as much as fi've milliamperes. This is likely to cause sticky magnetic operation, causing slow opening of contacts. Accordingly, it is the object of this invention to provide a word counter which is connected into a teletype- Writer line or the like without introducing any inductance into Ithe circuit, and introducing only a negligible amount of resistance.

Accordingly, it is an object of this invention to provide a word counter for connection to a teletypewriter circuit or the like wherein even a rather high leakage current produces no reaction, and wherein a much lower than normal line current produces a full and complete reaction.

More specifically, it is an object of this invention to provide a word counter wherein an electromagnetic counting device is `operated by a transistor connected across a teletypewriter line or the like.

Yet another object of this invention is to provide a word counter which is electromagnetically operated and wherein the electromagnet normally operates with a very small air gap, and wherein the armature normally need not move more than a small part of its full operating stroke.

Otherand further objects and advantages of the presen-t invention will be apparent from the following description when taken in connection with the `accompanying drawings wherein:

FIG. l is a perspective view of the outside of a word counter constructed in accordance with the principles of this invention.

FIG. 2 is a perspective view showing the word counter as adapted for panel or rack mounting.

FIG. 3 is a perspective view of the word counter with the case removed, taken from above and to the rear yand to one side.

FIG. 4 is -a perspective view of the word counter with the case removed, taken from below and to the rear, and rom the opposite side.

FIG. 5 is a longitudinal sectional view through part of the drive mechanism as taken substantially along the line 5--5 in FIG. 4.

FIG. 6 is a cross-sectional view through a part of the actuating mechanism or drive train as taken substantially along the line 6 6 in FIG. 4.

FIG. 7 is a schematic diagram illustrating the electrical aspects of the invention.

FIG. 8 is a graph representing the response of the word counter.

In FIG. 1, there is shown a word counter identified generally by the numeral l@ and adapted as a table model. The word counter includes a generally rectangular housing or casing l2, having a screened Ventilating opening 14 in one side thereof. The word counter is provided with -a front cover 16, incorporating a counting device or totalizer having numerals visible lthrough a window at l, tand having `a knurled reset knob 20. Such counting devices `or totalizers are well known in the art, and the one incorporated in the word counter herein may be of any known type. An on-oi switch 22 `also is provided in the front cover. Wires 24 are shown leading from the housing, and may be suitably connected to a teletypewriter line and to `a power line.

The word counter is shown in FIG. 2 adapted for rack mounting. The word counter 10 remains as before, except that a panel 26 is incorporated between the cover 16 and the housing l2. This panel is conventionally connected to a rack 28 by means of screws 30.

The mechanical construction of the word counter l0 is shown in FIGS. 3 and 4. The mechanical construction includes a base plate 32 having a short forwardly extending hexagonal rod 34 at a pair of diagonally opposite corners. These rods are provided with reduced diameter forward extensions 36 having tapped axial apertures therein receiving screws 38 (FIG. l) holding the cover i6 in place. Longer hexagonal rods 4t) extend rearwardly from the base plate 32 and are provided at the opposite ends with threaded axial apertures 42. The apertures at the forward ends of the rods 40 are not shown, but it will be understood that headless screws are threaded into these apertures and into corresponding apertures in the rear ends of the short rods 34 to hold the rods 34 and 4G on the base plate.

The internal construction of the word counter further includes a mounting wall or plate 44 perpendicular to the base plate 32 and extending transversely thereof. The mounting wall or plate 44 is secured to the base plate by means of suitable flanges 46 on the mounting plate secured to the base plate by means such as nuts and bolts. Furthermore, the mounting plate is provided along one corner with a flange or gusset 43 having a turned over flange Sil at the tip thereof secured by means such as a nut and bolt to the base plate 32. The iiange or gusset 48 further is provided with a right angle flange S2 spaced from the base plate 32, and mounting a lamp socket Sci. A light bulb 56 is ydetachably received in the socket S4,

. and projects from it through a relieved area 58 along the edge of the base plate into the vicinity of the counting device or totalizer whereby to illuminate the dials or numerals 18 thereon.

On one side of the mounting plate 44, as shown in' EIG. 3, there is mounted a small electric motor 66, preferably of the shaded pole type and driven at a constant speed from lcommercial power lines. The physical connections of the various electrical components will not be Specifically described with regard to FIGS. 3 and 4, since they are more readily seen from the schematic wiring diagram of FIG. 7. The rearwardly extending end of the shaft of the motor y66 is provided with a fan 62, preferably of molded plastic such as nylon. The fan is positioned adjacent the screened opening 14, and as will be apparent, other openings, not shown, are provided for a continuous air path through the word counter.

A condenser 64 also is mounted 'on the same side of the mounting plate as is the motor 61B. The condenser is mounted by conventional means, and forms a part of a powersupply hereafter to be set forth.

in addition, there is mounted on the same side of the mounting plate an electromagnet 66 comprising a pair of coils 68 wound on a corerhaving a pair of poles 70. An armature 72 is pivotally mounted on a stud 74 suitably secured to Ythe base plate 32, and has the front end thereof in `close proximity to the tips of the poles 7f3. The armature is provided with a rearwardly extending tail 75, and a coil spring 76 is stretched between this tail and a post 78 mounted on the base plate 32, whereby normally to hold the armature away from the tips of the poles 76.

The stem Sil of a clutch control fork S2 is fixed on the side ef the armature for movement therewith. The stern extends through an aperture 84 in the mounting plate 44,

and as will be seen in FIG. 4, is provided at its opposite end with a transverse member $6 supporting a pair of tines 86 Iand 90 -respectively having right angularly disposed tips 92 and 94. The function of the control fork will be set forth more fully hereinafter.

On the opposite side of the mounting plate 4'4, as seen in FIG. 4, there is provided a small transformer 96. A disk rectifier 9S is mounted adjacent the transformer. A transistor 10ft also is mounted on this side of the mounting piate as is a terminal strip 102.

The forward end `of the motor shaft extends through an opening in the mounting plate 44 and is provided with a worm 164 meshing with a worm gear 106 fixed on the end of a shaft assembly 108. The shaft assembly is journaled in the plate 32 and also in a bracket 110 fixed to the mounting plate 44. The shaft assembly preferably is mounted in nylon bearings one of which is illustrated at 112 in the base plate 32.

In order to operate the shaft assembly at the proper speed in accordance with the speed of transmission over the teletypewriter line, i.e. in accordance with a word rate of 60, 75 or 100 words per minute, the gear 106 is replaceable. The diameter `of the gear 1.66 determines the gear ratio with the worm 164, and the motor 60 is adjustably mounted by means of a bolt-in-slot connection 114 in order to mesh the worm with the gear regardless of the size of the gear. As will be apparent, the aperture 116 through which the forward end of the motor shaft extends is sufficiently large to allow the motor to be shifted a substantial distance.

The shaft assembly 108, as best may be seen in FIG. 5, comprises a relatively small diameter shaft 118, journalled in the bracket 110` and having the gear 106 fixed thereon. The gear preferably is rnade of nylon, while the worm with which it meshes is of metal. The shaft 118 terminates short of the base plate 32, and the end thereof is received in a bearing sleeve 120 inserted in the enlarged end 122 of a shaft 124 extending through the nylon bearing 112 in the base plate 32 and having a worm 126 fixed on the end thereon, or formed integral therewith. The worm 126 meshes with a gear 128, driving the counting device or totalizer previously referred to.

Two clutch plates 130 and 132Yare keyed or otherwise nonrotatably secured to thegshaft 11S, but are axially movable relative to this shaft. The bearing sleeve 120 spaces the clutch plate 130 from the end of the shaft enlargement 12,2, while the other clutch plate 132 is positioned on a sleeve 134 fixed on the shaft 118 and abutting the `clutch plate 130. A spring 136 encircles the sleeve 134 and is held against the clutch plate 132 by a nut 133 and a jam nut 144i.

The confronting faces of the clutch plates 13G and 132 bear against felt washers 142 and 144, respectively and a driven clutch plate 146 is resiliently gripped between these washers. An axial pin 146` on the driven clutch plate extends into a notch 150 in the periphery of a disk or flange 151 on the shaft enlargement 122, whereby to drive the shaft 124 with a driven clutch member 146. The periphery of the driven clutch member 146 is provided withsix equally arcuately spaced notches 152 adapted to be entered by one or the other of the ends or fingers 92 and 94 of the tines of the clutch control fork. The spring 76 urges the finger 94 resiliently against the periphery of the driven clutch member and tends to urge the linger 94 into one of the notches or recesses 152 as is shown in FIG. 6. When the electromagnet structure 66 is actuated, the armature 72 is pivoted and this tends to bring the end or finger 92 into one of the notches 152, the finger 94 simultaneously being urged away from the periphery. l

Normally, when the magnet is off, the finger 94E- Will ride on theperiphery of the driven clutch member 146. However, if the magnet remains in oi condition for long enough, as if the line should go dead, the finger 94 would drop into a notch 152 to halt the driven member, the felt washers thereafter slipping along the faces thereof and the totalizer being stopped. Similarly, most of the time when the magnet is in on condition, as when characters are being transmitted, the finger 92 will ride along the periphery of lthe driven clutch member 146. As is known, the time period for transmitting a character is divided into five increments, the current being on for di'erent ones of the increments depending upon the character being transmitted. At the end of the character, the current cornes on as a stop condition and stays on for `a predetermined period. The gear ratio of the worm 104 and gear 106 is so chosen that'the driving clutch members and driven clutch member make slightly less than one sixth of a revolution during the five increments of the transmission period for a character, and the full on line current for the stop condition comes on just as one of the notches 152 approaches the finger 92. The finger thus is pressed against the periphery of the driven clutch member, and dropped into the notch to stop the driven clutch member after exactly one sixth revolution. At the end of the stop signal, the line current is momentarily full off, and this causes the spring 76 to pivot the armature whereby to retract the finger 92 from the notch or recess 152. Since the motor 60 operates continuously whenever the word counter is turned on, the driven clutch member and totalizer then begins to move with the driving clutch members and the shaft 118.

As will be observed in FIG. 6, the finger 92 is displaced somewhat over degrees in the direction of rotation of the shaft and clutch members from the position of the finger 94. Accordingly, when the line current goes off at the end of a stop period and the spring 76 retracts the finger 92, the finger 94 has already been passed by the nearest notch, and the finger 94, thereupon rides on the periphery of the driven clutch member, rather than dropping into one of the notches. The full on line current comes on with the stop signal before the finger 94 can drop into a notch.

The worm 126 and gear 128 have a gear ratio of 10 to 1. Accordingly, for each full revolution of the shaft 124, the counting device or totalizer registers one unit on the counter. 1n other words, the shaft of the counting device seamos or totalizer makes one tenth revolution for each six printing telegraph characters.

In accordance with the foregoing construction, it will be apparent that when the magnet 66 is de-energized, the linger 94 will normally engage the periphery of the driven clutch member to limit movement of the armature, thus providing a small magnet airgap during normal telegraph signals. rThis increases magnet sensitivity. Only conditions of distorted telegraph signals or an open line condition will cause finger 94 to enter a slot in disc 146, in which case a maximum magnet air gap condition will exist. Thus, for normal operation, an air gap less than the maximum occurs.

Reference to the schematic wiring diagram FIG. 7, will indicate the connection of the various parts. Thus, the electrical power supply line is connected at the terminal strip to the switch 22, and through the switch tothe light 56 in paraliel with the motor 6d and also in parallel with the primary of the transformer 96. The rectiiier 93 is of the full wave variety and is connected across the output of the transformer, the condenser 64 being connected across the output of the rectifier as indicated. The positive terminal of the con-denser and of the rectifier is conected to the emitter of the transistor 100, while the negative terminal is connected through the coils 68 of the magnet structure 66 in series to the collector of the transistor. (The transistor 160 preferably is of the 2N352 type.) A resistor d is connected between the base and the emitter of the transistor and also into the signal line as connected at the terminal strip 102.

The operating characteristics of the circuit including the transistor are illustrated by the graph in FIG. 8. The resistor 154 is preferably of 15 ohms. Although the signal line is connected in series to the terminal strip 102, and in series through the resistor 1.54, the line current of twenty milliamperes is so small that the voltage drop is negligible. When a 15 ohm resistor is used, as indicated, the 15 ohm curve of FiG. 8 results. Thus, for the maximum leakage current of ve milliamperes, the load current is negligible. However, upon rising of the input current to as little as fifteen milliamperes, the minimum to be expected, the load current or output current of the transistor rises to its maximum value. A curve also is shown for an 18 ohm resistor, and it will be apparent that there is a more substantial output current at the tive milliampere leakage current, and hence the l5 ohm load is to be preferred. Lower values of resistance are not desirable since they may not allow a full output current to be supplied when the line current drops to fifteen milliamperes.

The transistor introduces no inductive load into the line, and the resistance introduced is more or less negligible. Furthermore, when the Word counter is designed to operate on a twenty milliampere line, as disclosed, it can also be used on a sixty milliarnpere line without requiring any change whatsoever.

From the foregoing it will be apparent that an improved word counter has been disclosed, being superior in electrical and mechanical characteristics. Various changes in structure will no doubt occur to those skilled in the art, and will be understood as forming a part of the invention insofar as they fall within the spirit and scope of the -appended claims.

The invention is claimed as follows:

l. A Word counter for teletypewriter circuits and the like comprising a base including an intermediate longitudinal wall and a transverse wall adjacent one end of said longitudinal wall, a housing detachably mounted on said base and including a Wall disposed adjacent said transverse wall and having a window therein, a counter mounted on said transverse Wall forwardly thereof and visible through said window, said front wall having opening means therein, drive means operatively connected to said counter and extending through said opening means and on one side of said longitudinal wall, said longitudinal wall having opening means therein and said drive means further extending through this opening means to the other side of said longitudinal wall, said drive means on the first mentioned side of said longitudinal wall having clutch means therein, electric motor means connected to said drive means on the other side of said longitudinal wall for driving said drive means, further opening means in said longitudinal wall, clutch control means extending through said further opening means and operatively connected to said clutch means for alternately rendering said drive means effective and ineffective, a-n electromagnet mounted adjacent said transverse wall on said other side, means operatively connecting said electromagnet to said clutch control means for operating said clutch control mea-ns, a pair of terminals supported from said base and adapted for connection to a teletypewriter line or the like, means electrically connecting said terminals to said electromagnet, terminal means supported from said base and adapted for connection to a power source, and electric means connecting said terminal means to said motor.

2. A word counter for teletypewriter circuits and the like `as set forth in claim 1 wherein the means electrically connecting the terminals to the electromagnet comprises electronic switch means non-responsive to currents below a predetermined minimum,

3. A word counter as set forth in claim 2 wherein the electronic switch means comprises a transistor and a resistor, said resistor being connected directly across said terminals, said transistor having a base, a collector element and an emitter element, said base and one of said elements being connected directly across said terminals.

4. A word counter as set forth in claim l and further including a transformer and a rectifier mounted on said one side of said longitudinal wall.

5 A word counter as set forth in claim 1 wherein the clutch means has arcuately spaced stops thereon, wherein the eleotromagnet has an armature, and wherein the clutch control means comprises `an elongated fork and a stem disposed substantially perpendicular to the drive means in the vicinity of the clutch, said stem being operatively connected to said armature, said fork further having a pair of spaced -tines having portions thereof alternately engageable with the stops of the clutch means.

6. A word counter as set forth in claim 5 wherein the fork is made of sheet material and the tine portions engageable with the clutch means stops comprise bent-over tips on said tines.

References Cited in the file of this patent UNITED STATES PATENTS 267,062 Cowell Nov. 7, 1882 1,977,781 Staegemann Oct. 23, 1934 2,522,734 Wood Sept. 19, 1950 2,584,990 Diamond a Feb. 12, 1952 2,827,995 Keith et al. Mar. 25, 1958 2,864,975 Sumner Dec. 16, 1958 2,866,925 Wunderman Dec. 30, 1958 FOREIGN PATENTS 772,055 Great Britain Apr. l0, 1957 OTHER REFERENCES Bell Telephone Labs. Ins., The Transistor, Selected Reference Material on Characteristics and Applications, (1951), page 198 relied on.

A Phototransistorized Photoelectric Counter from Radio and Television News, June 1954.

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