US2926602A - Automatic printer - Google Patents

Description

March 1, 1960 MacDONALD ErAL AUTOMATIC PRI TER Filed May 20. 1957 4 Sheets-Sheet l INVENTORS.

INVENTORS.

4 Sheets-Sheet 2 AUTOMATIC PRINTER D. N. M DONALD ETA]- QQQEQ A March 1, 1960 Filed May 20, 1957 Match 1, 1960 D. N. MacDONALD ETAL AUTOMATIC PRINTER 4 Sheets-Sheet 3 Filed May 20, 1957 mwefl m 0N5 r v; 0 W W Mm J M m Mm. m:

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AUTOMATIC PRINTER Filed May 20, 1957 4 Sheets-Sheet 4 4 V fn iz V AUTOMATIC PRINTER Duncan N. MacDonald, Arcadia, and Edward L. Glaser, Altadena, Calif., assignors to Burroughs Corporation, Detroit, Micln, a corporation of Michigan Application May 20, 1957, Serial No. 660,318

Claims. (Cl. 101-93) This invention relates to printing machines and, more particularly, is concerned with a high-speed tabulating device for printing alphanumerical information.

Printing machines for tabulating information, such as derived from a computer, for example, are well known. Such printing machines can be generally classified as one of two types. In the series type, one character is printed at a time, successive characters being printed until a complete line is made, at which time another line is started. The ordinary typewriter forms a basis of a printing machine of this type. In the parallel type, a complete line of characters is printed out simultaneously in the manner of the familiar adding machine. Printing machines which are a hybrid of these two types also have been developed in which groups of characters but not complete lines of characters are printed out during each print cycle.

Printing machines of the series type are generally simpler in construction and simpler in the circuitry required to control them from the input information. However, printing rates for the series type printing machine are relatively low. Printing machines of the parallel type can be operated at very much higher speed by printing out complete lines during each print cycle. However, their mechanism is much more costly and complex and generally the control circuitry is complicated by the requirement of a memory arrangement by which a complete line of information can be stored at a time.

The present invention is generally classed as a seriestype print machine, although in one embodiment it may be considered a series-parallel type machine. It is characterized by its relative simplicity, ruggedness, and low cost of construction and operation. Although it is a series-type printing machine, it is capable of printing speeds which are considerably in excess of known seriestype printers, although still not as fast as is achieved by some parallel-type printers. Thus, the present invencost.

The present invention achieves these results by means of a novel printing arrangement which in essence consists of a cylindrical type wheel having type characters arranged around the outer circumference in the form of a helix. The type wheel is continuously rotated and at the same time is advanced across the face of theprinting medium along its axis of revolution by an amount equal to the pitch of the helix with each revolution of the type wheel. Thus, each of the type characters in one turn of the helix is brought opposite a fixed point on the printing medium during one revolution of the type wheel. Successive revolutions of the type wheel bring each of the type characters opposite other fixed points along a line, the points being spaced by an amount equal to the pitch of the helix. A print bar extends in back of the printing medium and strikes a character on the type wheel through the printing medium to print out selected characters in response to the input information.

tion provides moderate printing speed at relatively low.

For a better understanding of the invention, reference should be had to the accompanying drawings, wherein:

Fig. 1 is a plan view of the printer according to the present invention;

Fig. 2 is a sectional view taken substantially on the line 2-2 of Fig. 1;

Fig. 3 is an end view looking at the right-hand end of the printer as shown in Fig. 1;

Fig. 4 is a schematic showing of the commutator assembly and control circuit associated with the printer of Fig. 1;

Fig. 5 is a fragmentary plan view of a modified version of the printer of Fig. 1;

Fig. 6 is a sectional Fig. 5; and

Fig. 7 is a schematic block diagram of a suitable view taken on the line 6-6 of control circuit for use with the modified version of the printer of Figs. 5 and 6.

Referring in particular to Figs. 1-3, the numeral 10 indicates generally the main frame of the printer, the main frame including a pair of spaced parallel side plates 12 and 14. Journaled in the side plates 12 and 14 is a rotatable keyed shaft 16 on which is carried a type wheel 18. The type wheel 18 is arranged to slide along the shaft 16 in the direction of the axis of rotation, but

by virtue of a key 20 engaging key slots in the shaft 16 and in the type wheel 18, rotational movement is imparted to the type wheel 18 by rotation of the shaft 16. In the embodiment shown in Figs. 1-3, the type wheel 18 is provided around its periphery with raised type characters representing the numerals 0 through 9 and the sign characters and The type characters are arranged around the outer periphery of the type wheel 18 in a single helical turn.

To rotate the shaft 16 and the associated print wheei 18, a suitable motor 22, mounted on the main frame 10, drives the shaft 16 through a belt drive, for example. To this end a belt pulley 24 is secured to one end of the shaft 16, a suitable fiat belt 26 extending between the shaft of the motor 22 and the belt pulley 24.

Axial movement of the type wheel 18 is achieved by means of a bracket 28 having arms 29 extending on either side of the type wheel 18 by means of which the type wheel maybe urged along the shaft 16 in an axial direction. ;The bracket 28 is slidably supported by means of a fixed shaft 30 secured at its ends in the side plates 12 and 14 of the main frame 10. By means of openings in the ends of the arm portions 29 of the bracket 28 through which the shaft 16 passes, the bracket 28 is also slidably supported by the shaft 16.

Movement is imparted to the bracket 28 by means of a flat steel band 32. One end of the flat steel band 32. is

' wound on a spring-loaded drum assembly, indicated generally at 34, by means of which tension is applied to the steel band 32. for urging the bracket to the left as viewed in Fig. 1.

The other end of the steel band 32 is secured to a drum 36, the drum 36 when rotated drawing the bracket 28 to the right, as viewed in Fig. 1, against the action of the spring-loaded drum assembly 34. The drum 36 is rotatably supported by a vertical shaft 38 journaled at its ends in suitable brackets 40 secured to the outer surface of the I end plate 14. A worm wheel 42 is journaled on the shaft 38, the worm wheel 42 being rotated by a worm gear 44 on the end of the shaft 16, whereby rotation of the shaft 16 imparts rotation to the worm wheel 42.

To rotate the drum 36 in one direction from the worm wheel 42, a clutch arrangement is provided which includes a driving member 46 which is feathered or keyed to the shaft 38 and engages a mating driven member 48 integral with the worm wheel 42. A spring 50 urges the driving member into engagement with the mating member 48. The clutch is disengaged by a runner 52 engaging an annular groove in the driving member 46. The runner 52 is actuated by a solenoid 54 through suitable linkage whereby energization of the solenoid 54 disengages the clutch. This permits the drum 36 to rotate freely, whereby the bracket 28 may be returned to its left hand position by the action of the spring-loaded drum assembly 34.

The diameter of the drum 36 and the gear ratio of the worm drive imparting rotation thereto from the shaft 16 are designed to advance the bracket 28 and associated type wheel 18 a distance equal to the pitch of the helix formed by the type characters on the type wheel with each complete revolution of the shaft 16. By this means it will be seen that the type characters in effect thread themselvespast a fixed point during each revolution of the shaft 16, the fixed points during successive revolutions of the shaft 16 being spaced parallel to the axis of rotation thereof a distance equal to the pitch of the helix.

The solenoid 54 is actuated by means of a microswitch 56 mounted on the inside of the end plate 14. A lug 58 secured to the bracket 28 engages the microswitch 56 when the bracket 28 reaches the right hand extent of its travel. Actuation of the microswitch 56 energizes the solenoid 54 from a suitable electrical energy source (not shown) thereby disengaging the clutch and permitting the bracket 28 and type wheel 18 to return to the left hand extent of their travel.

It should be noted at this point that a positive-acting clutch is provided, preferably of the type having engaging V grooves as shown in Fig. 3. The angular spacing between the V grooves is to the angular rotation imparted to the clutch with one revolution of the shaft 16. This insures that when the clutch engages, the same relationship between the rotational position of the type wheel 18 and the axial position thereof is maintained. By this means, characters printed in successive lines always fall directly below each other in vertical columns.

Printing is done on a suitable printing medium, such as a strip of paper 60 (see Fig. 2). The paper is advanced downwardly by means of a pair of paper feed rolls 62 between which the paper passes. The paper feed rolls 62 are preferably rotated by a solenoid 64 which advances the paper in incremental steps through a ratchet and pawl linkage as indicated generally at 66 in Fig. 3. The solenoid 64 is connected in series with the solenoid 54 so that the paper is advanced each time the print wheel completes a line and is returned to its initial left hand position. pair of guide shafts 68 extending between the side plates 12 and 14 of the frame that supports rollers 69. To effect printing on the paper 60, print actuating means is provided which includes a printing bar 70 extending the width of the paper on the opposite side of the paper from the type wheel 18. The printing bar 70 is supported at its ends by a pair of bell-crank arms 72 and 74 which are respectively pivotally supported, as indicated at 76, to

. the side plates 12 and 14 of the frame 10. The opposite ends of the bell-crank arms 72 and 74 are respectively linked to a pair of solenoids 78 and 80. Suitable spring means, such as indicated at 82, normally holds the print bar 70 in spaced relationship with respect to the type wheel 18.

A printing ribbon, such as indicated at 83, is fed between 21 pair of ribbon reels 84 and 86 secured to the end plates 12 and 14 by suitable bracket means 88 and 90. The reels may be spring loaded to hold the ribbon in tension, and the reel 84 may be provided with overrunning clutch means which permit the ribbon to advance only from the reel 86 to the reel 84. The ribbon is supported in the space between the type wheel 18 and the paper 60 by a pair of spring guide clips 92 and 94 secured to the respective arms 29 of the bracket 28. The spring clips preferably grip the ribbon tightly enough to withdraw The paper is preferably threaded between a 4 ribbon from the reel 86 during the return of the type wheel 18.

Thus, when the solenoids 78 and are energized, the print bar '70 presses the paper 60 and the ribbon 83 against a type character on the type wheel 18 which is at that instant directly opposite the type bar 70. With proper timing of the energization of the solenoids 78 and 80, any selected one of the type characters can be printed out while the type wheel 18 is continuously rotated. A whole line of type is generated by actuating the type bar 70 once during each successive revolution of the type wheel 18, whereby a series of type characters are printed out at intervals on the paper corresponding to the pitch of the helix formed by the type characters on the type wheel 18.

The solenoids 78 and 80 are controlled in response to information fed to the printer. One suitable control circuit is shown in Fig. 4 for printing out decimal characters. Synchronization with the rotation of the type wheel 18 is achieved through a commutator indicated generally at 96 mounted on the outer face of the end plate 12 and rotated by the shaft 16. The commutator includes an insulating plate 98 having a series of equally spaced contacts 100, the contacts being angularly spaced the same amount as the type characters on the periphery of the type wheel'18. The corresponding type characters are indicated in Fig. 4 by the numerals 0 through 9 and the sign characters and One contact, indicated at 102, has a corresponding blank space on the periphery of the type wheel 18.

A rotary contact arm 104 is secured to the shaft 16 and rotated thereby. The arm 104, as it is rotated, successively engages the contacts and 102. A suitable slip ring arrangement, including a brush 106 and ring 107 insulated from the shaft 16 completes an electrical circuit between the contact arm 104 and a source of potential 108. Pulses are thereby formed as the arm 104 successively engages the contacts of the commutator.

Assuming, for example, that the printer is to be used in' combination with a source of binary-coded decimal digits received in the form of D.C. levels, as from an electronic computer, paper tape or magnetic tape readers, or the like, such levels are applied to four and gates 110. Each of these and gates is connected to the blank contact 102 of the commutator 96. Once each revolution of the shaft 16 a pulse is produced as the circuit is momentarily completed between the potential source 108 and the contact 102. This pulse gates open the and gates 110 thereby transferring the D.C. levels representing the binary-coded digital information to the respective four triggers forming a counter 112. The counter 112 is a conventional binary type counter made up of trigger circuits and is arranged to be counted down by a series of input pulses.

All of the contacts 100 of the commutator 96 are connected in series to the counting pulse input of the counter 112. Thus as the arm 104 of the commutator 96 is rotated past successive contacts, a series of pulses are generated which are applied to the counter 112. The counter is arranged to count down and produce an output carry pulse when it passes through zero. The output carry pulse from the counter 112 is applied to the type actuator solenoids 78 and 80.

It will be appreciated from the above description that by means of the control circuit of Fig. 4, the solenoids are actuated in response to the input digit information stored in the counter 112, since the commutator must rotate through a number of contact positions equal to the number stored in the counter 112 before an output pulse is generated for actuating the type bar 70. For example, if the binary-coded decimal digit 5 is stored in the counter 112, the shaft 16 must rotate the commutator arm 104 past six contacts to the contact corresponding with the type character 5 on the type wheel. These six pulses count the counter 112 back to 0, producing an output pulse when the commutator arm 104 engages the contact 100 corresponding to thetype character position At this instant the type bar 70 is of the type wheel. actuated, thereby typing out the number 5 on the surface of the paper 60. I

The printer and associated control circuit as thus far described are particularly suited to the printing of numeric information. Where alphanumeric information is to be printed, a modification of the printer is desirable, as hereinafter described in connection with Figs. 5-7. While the printer as above described may be used for alphanumeric information by enlarging the type wheel to provide all the necessary characters in one helical turn, the speed of operation is adversely aifected, since the speed of the moving type past the print bar is the principal limiting factor in the printing rate.

In the modified version as shown in Fig. 5, a printing wheel 118 is provided in which the alphanumeric type characters are spaced around the outer periphery of the type wheel in four helical turns, thereby providing for four times as many type characters as in the above-described arrangement using a single helical turn of type characters. In place of the single type bar 70, four type bars 120, 122,124, and 126 are arranged in a quadrant, as best shown in Fig. 6. The upper two print bars 120 and 122 are supported at their ends by suitable bell-crank arms 123 and 139 respectively, which are pivotally secured to the end plates 12 and 14 of the main frame 1% at common pivot points 132. The bell-crank arms 128 and 1910 project in opposite directions and are linked to separate pairs of actuating solenoids 134 and 136 respectively. Similarly, the two lower type bars 124 and 126 are actuated by separate pairs of solenoids 138 and 140 respectively through suitable pivoted bell-crank arms 142 and 144. It will be understood that two solenoids are provided for each type bar at either end thereof, as in the previously described printer arrangement.

Each of the four type bars is provided with a plurality of spaced hammers; 141, 143, 145, and 147 indicate the hammers associated respectively with the four type bars 120, 122, 124, and 126. The distance between the hammers 141 associated with the type bar'120 is equal to four times the pitch of the helix formed by the type characters on the wheel 118. The hammers 143, 145, and 147 are respectively spaced the same distance on the other three type bars but are arranged in interlacing relationship such that the space between adjacent hammers is equal to the pitch of the helix. Thus with any given position of the type wheel 118, four different characters can be printed out by actuating means associated with the four printing bars.

Tooperate the modified printer described in connection with Figs. 5 and 6, a six-bit parallel alpha code is preferably used in which characters are represented by a fourbit binary-coded decimal numeric digit and a two-bit binary-coded decimal zone digit for each alphanumeric character. A suitable control circuit for operating the printer in response to alphanumeric information received serially from a digital source is shown in Fig. 7. The sixbit coded characters are fed to suitable four-place registers, the two-bit zone register being indicated at 146, and the four-bit numeric register being indicated at 148. The bits of successive characters are shifted in serially into the registers 146 and 148 by shifting pulses derived from a commutator identical to the commutator 96 of Fig. 4, and more specifically derived from the contact 1112 of the commutator 96 whereby one shifting pulse is received for each revolution of the type wheel 118. The shifting pulses may also be fed back to the digital information source to synchronize the shifting out of information from the source with the shifting in of information to the control circuit of Fig. 7.

The register 146 comprises eight trigger circuits which are arranged to store the two binary bits of each of four binary-coded decimal digits representing the zone information of the corresponding four "alphanumeric charae ters from the information source. Any one of four different decimal digits is thereby stored in each of the four successive positions of the zone register 146. Four and gates 150, 152, 154, and 156 are provided which are connected respectively to the pairs of triggers forming each of the four storage positions in the register 146. The and gate 150 is arranged to be gated open when a binary-coded decimal digit 0 is stored in the first position of the zone register 146. Similarly the gates 152, 154, and 156 are arranged to be gated open when the binary-coded decimal digits 1, 2, and 3 are respectively stored in the second, third, and fourth positions of the zone register 146. Each of the and gates is also connected to the contacts of the commutator 96, whereby pulses are passed by the particular and gates which are gated on by the zone register during any one revolution of the type Wheel 118. The pulses passed are in synchronism with the advancing of the type characters past the type hammers.

The numeric register 148 comprises four binary counters, each of which is equivalent to the counter 112 of Fig. 4. Each of these counters thus stores one of the binary-coded numeric digits as they are serially shifted through the register 148 from the information source. Each of the four binary counters forming the register 148 is counted down by pulses passed by the and gates 150, 152, 154, and 156 respectively. Carry pulses are produced by the respective counters when they are counted down through zero.

The carry pulses from the four counters forming the register 148 are coupled to the solenoids associated with each of the four type actuators of the printer through a commutating stepping switch indicated generally at 160. The stepping switch 166 is stepped in response to the impulses from the commutator 96 that shift the registers 146 and 148. The stepping switch 160 includes four poles which are connected respectively to the four pairs of type actuator solenoids. The stepping switch advances through four positions with each successive stepping pulse, contacts of each of the four positions being connected respectively to the carry pulse outputs of the four counters comprising the register 148. Thus as a coded alphanumeric character is successively shifted through the four positions of the registers 146 and 148 in synchronism with the revolution of the printing wheel 11%, it is associated through the stepping switch 160 with the same printing actuator. In this way the proper character isprinted at a given position on the paper during a selected one of four revolutions of the type wheel depending on which one of the four helical turns of type the character is located.

While operation of the above-described alphanumeric printer is believed evident from the description thereof, a

brief review of the operation follows by way of sum mary. The six-bit coded information received from the digital source includes a binary-coded numeric zone digit and a four-bit binary-coded decimal numeric digit. The zone digits, numbering 0 through 3, identify respectively the four turns of the helix on the type wheel where the particular alphanumeric characters are located. The numeric digits, which may have any value up to 0 through 15, identify the angular position on the type wheel wh re a particular type character is located. As the zone digit advances through the register 146, advancing one position for each revolution of the type wheel, it reaches the storage position in which the value is such as to gate open the associated and gate. Thus if the zone digit were a 0, the and gate would be gated open. With the proper and gate open, pulses are passed to the associated counter in the numeric register 148, where the numeric digit of the coded character is stored. It will be appreciated that the zone digit and the numeric digit of a particular character advance together through the four positions of the respective registers 146 and 148. With the associated and gate open, the counter in the numeric register is counted down through by a number of pulses corresponding to the value of the numeric digit stored in the counter. As a result, a carry pulse is generated after the type wheel has advanced through a fraction of a revolution so as to bring the appropriate type character identified by the numeric digit into position opposite one of the hammers. By the action of the stepping switch, the proper one of the four hammer actuators is connected to the carry output of the respective counters in the register to print the character in the proper position on the paper.

While one particular arrangement has been described to rotate, advance, and return the type wheel for printing out successive lines, it will be appreciated that other mechanical arrangements are possible for imparting the desired rotational advance to the type characters within a points along a line parallel to the axis of rotation of the type wheel. Various modifications are possible in the design of the driving circuits and the commutator also to accommodated difierent coded forms of the input.

We claim:

1. A tabulator system for printing out alphanumeric information received serially in the form of a six bit parallel alpha code including a four bit binary-coded decimal numeric digit and a two bit binary-coded decimal zone digit for each alphanumeric character, the tabulator system comprising a cylindrical type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in four separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, four type actuators, each actuator including a plurality of projecting hammers adapted to Strike the type characters moved into position by rotation and advancing of the type wheel, every fourth hammer being operated by the same actuator, the spacing between adjacent hammers being equal to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, means responsive to the zone digits of the coded alphanumeric characters and synchronized with the axial movement of the type wheel for selecting the hammer actuators to be energized during a given revolution of the type wheel, and means responsive to the numeric digits and synchronized with the rotational movement of the type wheel for pulsing the selected actuators at the time the desired characters pass under the hammers of the selected actuators.

2. A tabulator system for printing out alphanumeric information received serially in the form of a six bit parallel alpha code including a four bit binary-coded decimal numeric digit and a two bit binary-coded decimal zone digit for each alphanumeric character, the tabulator system comprising a cylindrical type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in four separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type Wheel, four type actuators, each actuator including hammer means adapted to strike the type characters, the hammer means of the respective actuators being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, means responsive to the zone digits of the coded alphanumeric characters and synchronized with the axial movement of the type wheel for selecting the hammer actuators to be energized during a given revolution of the type wheel, and means responsive to the numeric digits and synchronized with the rotational movement of the type wheel for pulsing the selected actuators at the time the desired characters pass under the hammer means of the selected actuators.

3. A tabulator system for printing out alphanumeric information received serially in the form of a six bit parallel alpha code including a four bit binary-coded decimal numeric digit and a two bit binary-coded decimal zone digit for each alphanumeric character, the tabulator system comprising a cylindrical type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in a plurality of separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, a plurality of type actuators, equal in number to the number of turns of the helix formed by the type characters on the type wheel, each actuator including hammer means adapted to strike the type characters, the hammer means of the respective actuators being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, means responsive to the zone digits of the coded alphanumeric characters and synchronized with the axial movement of the type wheel for selecting the hammer actuators to be energized during a given revolution of the type wheel, and means responsive to the numeric digits and synchronized with the rotational movement of the type wheel for pulsing the selected actuators at the time the desired characters pass under the hammer means of the selected actuators.

4. A tabulator system for printing out alphanumeric information received serially in the form of a code, the tabulator system comprising a type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in four separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, four type actuators, each actuator including a plurality of projecting hammers adapted to strike the type characters moved into position by rotation and advancing of the type wheel, every fourth hammer being operated by the same actuator, the spacing between adjacent hammers being equal to the Spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, and means for operating the actuators at selected times in response to the serially received coded information.

5. A tabulator system for printing out alphanumeric information received serially in the form of a code, the tabulator system comprising a type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in four separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, four type actuators, each actuator including hammer means adapted to strike the type characters, the hammer means of the respective actuators being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, and means for operating the actuators at selected times in response to the serially received coded information.

6. A tabulator system for printing out alphanumeric information received serially in the form of a code, the tabulator system comprising a type wheel having a plurality of type characters arranged in a helix around the 9 peripheral surface of the wheel, the characters being arranged in spaced relation in a plurality of separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, a plurality of type actuators, equal in number to the number of turns of the helix formed'by the type characters on the type wheel, each actuator including hammer means adapted to strike the type characters, the hammer means of the respective actuators being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, and means for operating the actuators at selected times in response to the serially received coded information.

7. A tabulator system for printing out information received serially in the form of a code, the tabulator system comprising a type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation in a plurality of separate turns of the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, a plurality of actuators, each actuator including hammer means adapted to strike the type characters, the hammer means of the respective actuators being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, and means for operating the actuators at selected times in response to the serially received coded information.

8. A tabulator system for printing out information received serially in the form of a code, the tabulator system comprising a type wheel having a plurality of type characters arranged in a helix around the peripheral surface of the wheel, the characters being arranged in spaced relation along the helix, means for rotating the type wheel, means for moving the type wheel along its axis of rotation by an amount equal to the pitch of the helix with each revolution of the type wheel, hammer means adapted to strike the type characters at spaced positions parallel to the axis of rotation of the type wheel as the wheel advances, the hammer means being spaced at intervals corresponding to the spacing between adjacent type characters as measured parallel to the axis of rotation of the type wheel, and means for operating the hammer means at selected times in response to the serially received coded information.

9. In a printer, means for supporting a record medium upon which it is desired to print at a plurality of positions spaced along a line on the medium, a circular member having a plurality of different printing characters arranged in a helix around the periphery of the member, the characters being arranged in spaced relation in a plurality of separate helical turns, means mounting the member so that its axis extends parallel to the line of printing positions on the record medium and so that it is rotatable about its axis and bodily movable therealong, means for continuously rotating the member about its axis and for continuously bodily moving the member along its axis of rotation as it rotates, the axial movement of the member being so related to its rotational movement and the helical formation of the printing characters around the periphery of the member that all of the printing characters successively thread past each of the printing positions of the record medium and means positioned opposite the circular member for effecting simultaneous transfer of one or more print characters from selected ones of the several turns of the helix as the characters are threaded past the printing positions.

10. An automatic printer for printing characters on a printing medium comprising a main frame, a type wheel having a plurality of type characters arranged in a plurality of helical turns around the outer periphery of the type wheel, means for rotating the type wheel, means for advancing the type wheel in one direction along its axis of rotation a distance equal to the pitch of the helix with each complete revolution of the wheel, means for returning the type wheel in the opposite direction along its axis of rotation at a high rate of speed after the wheel has been advanced to the limit of its travel by said advancing means, means supported by the main frame for movably supporting the printing medium in spaced but substantially tangential relationship to the outer periphery of the type wheel as it rotates, means synchronized with said type wheel returning means for advancing the printing medium a predetermined amount in a direction at right angles to the axial displacement of the type wheel each time the type wheel is returned, and a plurality of separately actuatable means for selectively engaging the printing medium with type characters in any one of the plurality of helical turns during one revolution of the type wheel.

References Cited in the file of this patent UNITED STATES PATENTS 723,567 White Mar. 24, 1903 950,473 Campbell Mar. 1, 1910 1,405,722 Siepmann Feb. 7, 1922 2,457,133 Deloraine Dec. 28, 1948 2,540,654 Cohen Feb. 6, 1951 2,600,952 Ackell June 17, 1952 2,773,443 Lambert Dec. 11, 1956 2,776,618 Hartley Jan. 8, 1957 2,802,049 Masterson Aug. 6, 1957 2,811,102 Devol Oct. 29, 1957 2,831,424 MacDonald Apr. 22, 1958 FOREIGN PATENTS 323,582 Italy Dec. 28, 1934

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