US3633499A

US3633499A - Printing mechanism

Info

Publication number: US3633499A
Application number: US840203A
Authority: US
Inventors: Gosta Curt Hjerpe
Original assignee: F A PREKO ING
Current assignee: F A PREKO ING; ING F-A PREKO
Priority date: 1968-11-14
Filing date: 1969-07-09
Publication date: 1972-01-11
Anticipated expiration: 1989-01-11
Also published as: FR2023294A1; SU382312A3; DE1942323A1; CH502898A; NL6917066A; SE332533B; GB1295469A; BE741707A

Abstract

Printing apparatus preferably for printing numerals in calculating machines is disclosed, such apparatus having a plurality of substantially sector-shaped-type carrying members, each of such members being pivotally mounted and provided with a predetermined number of illustratively impression-type members movable generally radially in the vicinity of the circumference of the sector-shaped portion. A ratchet mechanism is provided on each of the sector-shaped portions for ruling or interrupting movement of each of the type carrying members. A plurality of spring-loaded printing hammers are arranged to strike the type members to print selected characters, each of the hammers being provided with corresponding linkage for controlling its movement. The entire apparatus is preferably mounted on a laterally movable carriage, and electronic coding and sensing may be provided for controlling the apparatus for example, in the event of computerized operation.

Description

United States Patent [72] Inventor Gosta Curt Hjerpe Molndal, Sweden [21] Appl. No. 840,203 [22] Filed July 9, 1969 [45] Patented Jan. 11, 1972 [73] Assignee Ing. F-a Preko Molndal, Sweden [32] Priority Nov. 14, 1968 [33] Sweden [31] 15447/68 [54] PRINTING MECHANISM 23 Claims, 8 Drawing Figs.

[52] U.S.Cl. 10l/93C [51] Int. Cl B4lj [50] Field ofSearch 101/93 MN,

[56] References Cited UNITED STATES PATENTS 1,608,837 11/1926 Bryce 101/93 C 1,705,983 3/1929 Lasker et a1. lOl/93 C Primary ExaminerRussell R. Kinsey AttorneyDarby & Darby lOl/93C 101/93C ABSTRACT: Printing apparatus preferably for printing numerals in calculating machines is disclosed, such apparatus having a plurality of substantially sector-shaped-type carrying members, each of such members being pivotally mounted and provided with a predetermined number of illustratively impression-type members movable generally radially in the vicinity of the circumference of the sector-shaped portion. A ratchet mechanism is provided on each of the sector-shaped portions for ruling or interrupting movement of each of the type carrying members. A plurality of spring-loaded printing hammers are arranged to strike the type members to print selected characters, each of the hammers being provided with corresponding linkage for controlling its movement. The entire apparatus is preferably mounted on a laterally movable carriage, and electronic coding and sensing may be provided for controlling the apparatus for example, in the event of computerized operation.

PATENTED JAN! 1 1972 SHEET 2 [1F 8 1. ow 9n minnow 1 m2 3.333.499

SHEET 3 [IF 8 PATENTED JAN] 1 I972 SHEET 4 BF 8 PATENTEU JAM 1 i972 SHEET 5 BF 8 PATENTED JAN] 1 m2 SHEET 6 OF 8 PATENTED JAN] 1 1972 SHEET 7 [IF 8 mm mm mm PATENTED mu 1 1972 31 33499 saw a or a 39 fTTfiTiW 8 13H|IIIHHH 1 HHHHI'I' 1 PRINTING MECHANISM The present invention relates to a printing mechanism particularly for printing numerals in, for example, calculating machines and of the type comprising substantially circle-sector-shaped-type carriers adapted to be set and provided with radially movable types, means for ruling the type carriers in set positions, preferably spring-loaded printing hammers and cocking means, and a device for releasably hooking said printing hammers.

The invention has as its object to produce a printing mechanism which simultaneously satisfies a plurality of very far-reaching desires, such as a very small spacing, for example 0.1 inches for adjustment to typewriter text, very small assembly height, for example for rendering possible a laterally movable attachment in combination with a typewriter of the writing-ball type, and complete flexibility in the choice of mechanic or electric control of the printing mechanism with allowing for a high printing capacity. Further desires to be satisfied by the invention are low manufacturing costs, safe operation and long life.

A printing mechanism for the aforesaid objects is characterized according to the invention substantially in that every decade of the printing mechanism comprises two detail groups located to the side of each other and lying substantially entirely within the type width, one of said groups comprising the substantial part of the type carrier which shows a substantially radial portion and connected therewith a circumferential portion, said group also comprising a ruling hook disposed in the space inside of the circumferential portion for engaging with cogs formed on the inside thereof, for which ruling hook is provided a blocking member, the other of said detail groups comprising a member disposed on the circumferential portion of the type carrier for supporting radially inwardly directed shanks of the types and a preferably spring-loaded printing hammer disposed in the space inside of said supporting member.

A suitable embodiment of the invention will be described in greater detail in the following, with reference to the accompanying drawings in which:

FIG. I is a sectional view of the printing mechanism showing the type carrier in initial position with the printing hammer cocked;

FIG. 2 is a sectional view of the printing mechanism showing the type carrier latched in a setting position;

FIG. 3 is a view similar to FIG. 1 showing the hammer in a printing position;

FIG. 4 is a view similar to FIG. 2 showing the type carrier in an upper end position;

FIG. 5 is an elevational end view of the printing mechanism showing the drive shaft of the mechanism and motion-transmitting members for positioning a portion of the printing mechanism;-

FIG. 6 is a view similar to FIG. 5 showing linkage for suspending and positioning the printing mechanism.

FIG. 7 is a perspective assembly drawing of the printing mechanism and partially shown in an exploded view, FIG. 8 is a block diagram referring to an electronic unit for controlling the printing mechanism.

As appears most clearly from FIGS. 1-4, each of the types 1 of the printing mechanism is supported by substantially sectorshaped type carn'ers 2, in such a manner, that each of such type carriers is provided with types corresponding to the numerals 0 through 9. Each of the types 1, as appears most clearly from FIG. 3, is arranged so as to be radially movable in relation to the type carrier. Each of the type carriers 2, which freely can pivot about a shaft 3 common to all type carriers, comprises an entirely plane portion which preferably may be punched out of sheet metal. Said plane portion shows a substantially circular hub, a substantially radially directed portion and a substantially circumferential portion projecting from the end of said radially directed portion, each of the types being mounted on one side of said circumferential portion. For this purpose, each of the types is so designed that its shank projects substantially radially in relation to the type carrier and is movably placed in a bearing portion 2a which is rigidly connected with the circumferential portion of the type carrier, said bearing portion 20 on the side facing towards the type shank being provided with radiated grooves for the type shanks. The bearing portion 2a preferably may be formed of synthetic resin and be given a thickness such that the bearing portion together with the remaining part of the type carrier is lying entirely within the type width, although the type width may be chosen very small, for example 0.1 inches, in order to be in agreement with the type width usual at typewriters.

In the vicinity of the hub portion of every type carrier 2 a dog member 2b is pivotally rivetted, which is provided with. a substantially hook-shaped portion and loaded by a tension spring 20 mounted between said dog member and the radial portion of the type carrier, so that said dog member with its hook-shaped portion releasably embraces a rod 4a associated with a double setting bridge 4, said rod being adapted to cooperate with the dog members of all type carriers, in such a manner, that the setting bridge is rigidly connected with the shaft 3 common to all type carriers. Said shaft 3, as will be described later on, is adapted during every setting and printing operation to oscillate in clockwise direction between the starting position illustrated in FIG. 1 and a position somewhat past that shown in FIG. 3.

Upon the clockwise rotation of shaft 3 from the position shown in FIG. I, the rod 4a by means of the dog members 2b causes the type carriers 2 to participate in the swing of the setting bridge about the shaft 3 to the upper end position of the swing shown in FIG. 4. Said upper position is determined by a check rod 5 which extends through the printing mechanism and against which the upper end edge of a recess 2e made in the hub portion of every type carrier is intended to abut, provided that the type carriers are not therebefore obstructed in their swing in a swing position corresponding to a type being in position for printing. When a type carrier during its clockwise swing thus is blocked for setting, as it is illustrated in FIG. 2, the hook-shaped dog member 2b of the type carrier, as shown in FIG. 3, is swung out of the engagement with rod 4a against the action of spring 20 and by the action of said rod, which rod thereafter is allowed to slide along a surface of the dog member 2b, which surface is peripheral in relation to the shaft 3. During the anticlockwise return motion of the setting bridge 4, when the rod 4a again arrives at the position shown in FIG. 2, the dog member 2b by action of spring 2c again is swung into engagement with said rod which simultaneously is caused to abut to a stop surface 2d of the type carrier for nonresiliently resetting the type carriers to the starting position shown in FIG. I.

For rendering it possible to block the type carriers in individual setting positions during the clockwise setting motion, every type carrier is provided on the inside of its circumferential portion with a cog or ratchet-arrangement 2f corresponding to the existing types, with which cogs a corresponding latch or pawl 7 pivotally mounted on a shaft 6 is intended to be engaged by action of a locking member which is designed as an arm 9 pivotally mounted about a shaft 8. Said arm is loaded by a spring 10in that direction of swing in which the latch 7 is actuated in the direction of engagement, as appears from FIG. 2. Said arm 9 is adapted to be swung in anticlockwise direction to the end position of its swing and thereby to tension the spring 10, both during the setting motion of the type carrier in question to the blocking moment and during the resetting motion, as shown in FIG. 4, in which position the arm is adapted releasably to be retained in a way which will be described later on. In this cocked position of the arm 9 the corresponding latch 7 is swung in clockwise direction to the nonoperative end position of its swing by cooperation between the lower side edge of the'arm 9 and the corresponding upper edge surface of a finger 7a projecting substantially radially from the lower end portion of the latch in relation to the shaft 6. The latch, however, in its operative end position for blocking the type carrier 2, as shown in FIG. 2, is

actuated substantially by an end edge of arm 9 formed downwardly with increasing radial distance from shaft 8. Said end surface of the arm 9 thereby cooperates by key effect with an arc-shaped edge surface of the latch 7, the key angle as well as the positions of said contact surfaces in relation to the shafts 6 and 8 so being chosen that the latch 7 cannot be moved out of its position as long as the arm 9 by action of the spring 10 is retained in its position shown in FIG. 2.

The swinging motion of arm 9 to the swing end position shown in FIG. 4, by which motion the spring 10 is tensioned and the latch 7 is swung to its nonoperative position, is effected by a resetting bridge 11 common to all arms 9, which bridge by two end walls 110 is pivotally mounted about the shaft 6 for the latches 7. The end walls 11a of said resetting bridge are connected with one another at their end portions remote from the shaft 6, by means of a rod llb abutting to the upper surfaces of the arms 9, said rod upon clockwise swing of the resetting bridge effecting the anticlockwise swing of the arms 9 to said position shown in FIG. 4. The clockwise swing of the resetting bridge 11 is intended to be effected by two cam disks [2 abutting to radial sides on the end walls Ila in question, said cam disks being rigidly connected with a shaft 13. Said shaft 13, as the

aforementioned shafts

3, 6 and 8, is mounted in end walls 14 intended for the printing mechanism. Said end walls 14 also support the check rod 5, a holder 15 intended in part for the springs 10, and guide members l6, l7 and 18, respectively, provided for the type carriers 2, the latches 7 and the arms 9, respectively.

As it should have appeared from the above functional relation between type carrier 2, latch 7 and arm 9, the two lastmentioned details may be formed entirely plane, like the type carrier 2, by punching them out of sheet metal, and they may be arranged in a plane in common with the type carrier, all three of said details thus requiring very little of the width of the printing mechanism, preferably only one-third of the selected type width. According to the invention, the remaining part of the type width which is utilized in part for the bearing portion 2a intended for the types 1 and to some extent also by the dog member 2b, therefore can be utilized for the printing function.

In the space between the bearing portion 2a and the shaft 3 for supporting the type carriers, a printing hammer 19 is provided to the side of latch 7 and arm 9, said hammer being pivotally mounted about the shaft 6 intended in part for the latches 7, in such a manner, that printing hammer and latches are arranged alternatingly on said shaft. The complete set of printing hammers and latches is enclosed near to the end walls 14 by the end walls lla of the resetting bridge 11 which also are pivotal about the shaft 6. Each of the printing hammers 19, which is provided with a head 19a for striking against the angular end portion of the type shank of a type I, is spring loaded in the striking direction by a tension spring 20 stretched between the lower end portion of the printing hammer and the holder 15 for the springs 10. At some distance from shaft 6 the printing hammer is formed with a projection 19!) directed substantially to the shaft 3, which projection for cocking the hammers 19 in clockwise direction is adapted to cooperate with a second rod 415 at the double setting bridge 4 intended for setting the carriers 2. Said second rod 4b, upon the resetting motion of the setting bridge 4 from the position shown in FIG. 3 to the starting position shown in FIG. 1, causes by:- directly acting on said hammer projection 19b the hammer to swing into the cocked position shown in FIG. 1, in which position a ratchet 19c is caused to engage with a hooking bar 210 of the hooking bail 21, which hooking bar is intended for all hammers and extends between the two end wall portions 21b of the hooking bail which are disposed near to the end wall plates 14 of the printing mechanism. The hooking bail 21 is mounted with its two end wall pieces pivotally about bearing bushings 22 acting as a bearing for a shaft 23 which will be described later on. Each of the two end wall pieces 21b of the hooking bail 21 is formed with an upwardly directed projection, the upper end of which abuts to a corresponding cam disk 24. The two cam disks 24 are rigidly connected with the aforementioned shaft I3 which, as appears from FIGS. 5 and 7, is coupled with the shaft 23 by means of a transmission gear 25 with the gear ratio 1:1. It further appears from FIGS. 5 and 7 that on shaft 13 is arranged an eccentric disk 26 on which one end of a rod 27 is mounted, the other end of said rod being articulated by a journal 28 with an arm 29 which projects radially from and is rigidly connected with the shaft 3. Upon rotation of the shaft 13, thus, both the cam disks l2 and 24 and the eccentric disk 26 are caused to rotate and thereby by means of the rod 27 to impart to the arm 29 and, thus, to the shaft 3 an oscillating motion, in which motion the setting bridge 4 is caused to participate.

On the shaft 13, furthermore, is rigidly mounted an additional eccentric disk 30, on which is rotatably mounted one end of a link rod 31, the other end of which by means of a threaded stud 33 is articulated with a suspension means 32 for the mounting of the printing mechanism. In the lower corner portions of those end edges of the end wall plates 14 of the printing mechanism which face towards a paper platen 34, as appears most clearly from FIGS. 2 and 4, recesses [40 are arranged which are intended to receive each its of the aforementioned bushings 22, each of which is rigidly connected with a corresponding portion of the suspension means 32. For retaining the printing mechanism in the position shown in FIG. 6 relative to the bushings 22, a corresponding mounting member 35 rotatably mounted about the bushing 22 in question is releasably screwed into the outside of every end wall 14. Thus, upon the rotation of shaft 13 the printing mechanism, as indicated by the arrow a, is swung upwards and downwards by action of the eccentric disk 30 and by means of the link rod 31, in such a manner, that the printing mechanism is swung about the bushings 22, i.e., concentrically with the shaft 23 rotatabiy mounted in said bushings, so that during said swinging motion of the printing mechanism the center distances between the shafts 23 and l3 remain unchanged. The eccentric disk 30 and the link rod 31 as well as the cam disks l2 and 24 together with the corresponding projections 21c of the hooking bail are maintained in their definite lateral positions by action of a guide cam 36 mounted on the inside of every end wall plate 14, as shown in FIGS. 4 and 7.

In the embodiment illustrated in FIG. 7 the printing mechanism is mounted laterally movable, in such a manner, that the suspension means 32 comprises a carriage which in the embodiment shown is a substantially U-shaped bar 32a. Said bar, on the inside of its upwardly facing leg portions, is provided with V-shaped grooves for receiving a number of balls 32b intended to cooperate with corresponding grooveshaped recesses in a horizontal guide member 37. Said guide member 37 is intended to be rigidly connected with end wall plates 38 comprised in the machine in question, for example an accounting machine, of which plates only one is partially illustrated in FIG. 7. Said end wall plates 38 also are intended to support the roll 34 of the machine and to serve as a bearing for the shaft 23 intended for driving the printing mechanism, which shaft 23 besides is axially fixed in the end wall plates 38. The one cogwheel in the transmission gear 25 which is Iocated on the shaft 23, thus, can be moved along the shaft 23 together with the printing mechanism, whereby the printing mechanism by the rigid connection between the shaft 23 and said cogwheel is driven from the shaft 23 independent of the moving position of the printing mechanism.

The arms 9, as mentioned before, are intended to be retained in their cocked positions shown in FIG. 4 against the action of the springs 10, in which positions the corresponding latches 7 are moved into their nonoperative positions. Said retaining capacity is intended to be effected by an electromagnet 39 corresponding to every arm 9, each of said arms being provided with an armature 9a which corresponds to the magnet in question and in cocked position of the arm abuts to the stator of the electromagnet. Said arms 9 are made of nonmagnetic material, in order to prevent unfavorable magnetic in fluence via the arms 9 to the latches 7 and other adjacent details. The electromagnets 39, which for space reasons are placed in staggered relationship in the longitudinal direction of the arms 9 and arranged in groups of three magnets which in their turn are placed to the side of each other, are mounted on and electrically connected to a printed circuit card 40, which is mounted on the upper portion of the guide cam 16 and in the end wall plates 14 of the printing mechanism. As long as current flows through the electromagnets, the arms 9 are maintained in their cocked positions, but as soon as the current flow is interrupted by anyone of the electromagnets, the corresponding spring by means of the associated arm 9 moves the corresponding latch 7 into engagement with the cogs 2f of the type carrier 2 in question. If said release of the magnets 39 takes place during the setting motion imparted to the type carriers 2 by the setting bridge 4, the type carriers will be stopped by the latches 7 in question in positions corresponding to the release moment of the electromagnets in question during the setting motion. This embodiment is well adapted to be fitted to electronic as well as electromechanical calculating machines or the like, but the printing mechanism also can be imagined to be fitted to purely mechanical machines, in which case the electromagnets 39 can be exchanged against mechanic members.

In the embodiment shown the printing mechanism is intended for use in connection with electronic calculating machines or the like at which the numeral values are stored as binary information in an associated storage unit. FIG. 8 illustrates in a schematic way by means of a block diagram a suitable embodiment of an electronic control unit intended for releasing the electromagnets 39, the operation cycle of said unit being intended to be synchronized with the setting course of the printing mechanism by action of a photoelectric position transmitter comprised in the printing mechanism, which transmitter is illustrated in FIGS. 5 and 7 and indicated also in FIG. 8. In the embodiment shown the position transmitter comprises a radially projecting arm 41 which is rigidly connected with the shaft 3 and at its end portion remote from said shaft formed with an arc-shaped portion 41a projecting axially and being concentric with the shaft, which portion 41a is provided with five axially distributed and circumferentially extending rows with light openings designated by A, B, C, D and E. On one side of said axial portion 41a a tube lamp 42 is arranged which is intended to illuminate all hole rows and, as indicated in FIG. 5, disposed in a suitable lamp housing 43. On the other side of said portion 41a a group of photodiodes or the like corresponding to the hole row and designated by 44 are arranged on a holder 45 mounted between the end walls 14 of the printing mechanism, which holder as indicated by dash-dotted lines in FIG. 5 preferably is part of a housing assembled to one unit with the lamp housing 43.

The numerals to be set for printing by locking the type carrier 2 in question during the clockwise swing motion of the setting bridge 4 are in the embodiment in question intended to be registered in the storage shown in FIG. 8. Said storage preferably is a core storage in which said numeral registrations are intended to be sensed by decades and one numeral after the other in accordance with the order of the numerals in the setting direction on the type carriers. For rendering possible said sensing of the numerals one by one, the electronic part must be given continuous information on the current setting position of the type carriers, i.e., the electronic part must be kept informed on which numeral common to all type carriers is in setting position in the moment in question. This information is given to the electronic part by action of the code formed by the hole rows B-E, said code being sensed by the corresponding photodiodes 44 which transform the light signals arriving through said holes into corresponding electric signals which through a line group 46 are fed to a control transformer which, as appears from FIG. 8, also is connected to corresponding outlets 47 of the core storage. Said outlets 47 from the core storage are further connected, as also is shown, to a sensing member for unessential noughts, i.e., such noughts which precede the number proper and, therefore, are

not to be printed. Said sensing member is connected by a line 48 to a gate 49 to which also the outlet line 50 of the control transformer is connected. The outlet of the gate 49, as indicated schematically, can selectively be connected in proper order to a number of magnetoswitch circuits corresponding in number to the release magnets 39, the number of said switch circuits, thus', being 13 decades. The connection of the outlet of gate 49 to the different switch circuits is effected by the action of a decade selector shown in the drawing, which selector also is intended synchronously to shift an ingoing sensing line 51 between inlets of the core storage corresponding to the 13 decades. The shifting of the connections in proper order between the magnetoswitch circuits and the different inlets of the storage is effected by toggle circuits (not shown), in such a manner, that the decade selector for the synchronous stepping is controlled by a pulse generator which may be designed so as to emit a continuous sequence of pulses while the decade selector performs only one shifting sweep for every time a starting signal caused by a corresponding light opening in the hole row A is received from the corresponding photodiode 44 via a connecting line 52. Such a starting signal can also be supplied to the decade selector via an inlet 53.

In the embodiment in question the type carriers 2 have no types in the starting position shown in FIG. 1. After this position the types are arranged in the order of 0,l,2,39 and may thereafter, for example, be followed by a comma symbol. Immediately prior to the start of the clockwise swing motion of setting bridge 4 for setting the type carriers 2, a start signal is supplied to the decade selector via the inlet 53 whereby the decade selector timed with the signals received from the pulse generator senses the storage portions corresponding to the decade while simultaneously switching the outlet of gate 49 between the corresponding magnetoswitch circuits. During this sensing sweep which starts with the 13 decade and continues in proper order to the first decade, usually first a number of unessential noughts are met. Said noughts are transmitted via the outlet lines 47 of the storage to the control transformer as well as to the sensing member for the unessential noughts, which latter member via the outlet line 48 normally sends a signal causing the gate 49 to assume a state of conductive function. As the photodiodes 44 corresponding to the hole rows B to E in a corresponding starting position of the position transmitter 41 emit signals corresponding to zero to the control transformer, every registration of an unessential nought received from the storage effects an outgoing signal via the outlet line 50 of the control transmitter, the gate 49 and further to the magnetoswitch circuits in question which thereby interrupt the current flow through the corresponding magnets 39. Hereby the corresponding type carriers 2 are locked in their start positions by action of the associated latches 7 which are moved into their locking positions by ac tion of the springs 10 and by means of the arms 9. Said locking takes place by decades in a rapid rhythm and synchronously with the stepping of the decade selector to corresponding decades in the store of the magnetoswitch circuits, which stepping is controlled by the pulse generator. When during this first sensing sweep a registration of a numeral differing from zero is met in the storage, also this numeral is transmitted via the outlet lines 47 of the storage both to the control transmitter and to the sensing member for unessential noughts, said sensing member being so designed that the signal going out via the line 48 changes polarity and thereby interrupts the current flow through the gate 49.

Signals possibly going out from the control transmitter via the outlet line 50, therefore, will not be transmitted to corresponding magnetoswitch circuits even if such signals are emitted by the control transmitter due to essential noughts met during the continued part of the first sensing sweep. The latches 7 corresponding to essential numerals in decades in question, therefore, are retained in their nonoperative function positions shown in FIG. 4 and, therefore, the type carriers 2 corresponding thereto are allowed to follow with the setting bridge 4 when it starts its clockwise setting-motion. At the beginning of the setting motion of the type carriers 2 the outgoing signal of the sensing member for unessential noughts again is caused to change polarity and thereby also the position transmitter 41 assume the first setting position in which the type carriers are provided with noughts, the signals emitted from the photodiodes 44 corresponding to the hole rows B to E are not changed, so that the control transmitter still emits an outgoing signal for every zero registration read from the storage. As, however, the registrations corresponding to the unessential noughts already previously have caused the release of the latches 7 associated with the corresponding magnets 39, these registrations now are not of any importance, nor will such registrations sensed from the storage which refer to numerals differing from zero cause any release of magnets 39 associated with corresponding decades, because these sensed registrations will be compared with the signals which represent zero and are supplied to the control transmitter from the photodiodes 44 via the lines 46. During this second sensing sweep which is started by a signal emitted by the corresponding photodiode 44 through one of the first light openings in the hole row A to the decade selector via the line 52, thus, the current flow will be interrupted only for the electromagnets 39 corresponding to decades in which essential noughts have been sensed. The type carriers comprised in these decades, thus, will be locked in the setting position of the nought by associated latches 7.

When the type carriers 2 and thereby also the position transmitter 41 assume the next setting position corresponding to the numeral 1, a light opening in the hole row B will produce an outgoing signal from the corresponding photodiode 44 whereby the control transmitter so is switched that only registrations met in the storage and corresponding to the numeral I produce an outgoing signal via the line 50 and gate 49, which is maintained in conductive function state during the entire continued setting operation. Possible registrations in the storage which correspond to numeral 1, thus, will in the corresponding decades in question cause the locking of the type carriers in the setting position of numeral one. In a corresponding way all numerals registrated in the storage will during the sensing sweep in question he set in the decades intended. The time required in every setting position for setting all decades does not exceed -l0 ms. as long as the number of decades can be held within reasonable limits and, therefore, the complete setting of the printing mechanism can be effected very rapidly, which is highly important as hereby the applicability of the printing mechanism can be increased to a high degree.

The setting of the printing mechanism is made by starting from the backswept position shown in FIG. 6, in which position the shaft 13 of the printing mechanism is held in the position shown in said Figure as well as in FIGS. 1, 5 and 7 the drive shaft 23 being in its corresponding position shown in the same Figures. in this starting position of the printing mechanism the sensing of possible unessential noughts is commenced, which thereby are set by locking corresponding type carriers 2 in their starting positions shown. In direct connection therewith the drive shaft 23 of the printing mechanism is started for one clockwise revolution, during which the shaft 13 driven thereby is rotated through one anticlockwise revolution by means of the gear transmission 25. As soon as the anticlockwise rotation of the shaft 13 has commenced, the type carriers 2 are swung for their setting in clockwise direction by action of the setting bridge 4, the rotation of said bridge being effected by action of the eccentric disk 26 by means of the rod 27, the journal 28, the arm 29 and the shaft 3, which also effects the swing motion of the position transmitter 41 synchronized with the setting bridge. in the anticlockwise rotation of shaft 13 also participate the

cam disks

12 and 24 and the eccentric disk 30, of which said latter by means of the link arm 31 causes the printing mechanism to swing to the printing position indicated by dash-dotted lines in FIG. 6. After the completion of the setting motion and when the printing mechanism has arrived in its upper end position of the swing, the hooking bail 21 with its hooking bar 21a is swung out of the engagement with the spring-loaded printing hammers 19 by action of the cam disks 24 acting upon the hooking bail. Hereby the printing hammers are caused to strike against the types corresponding to the setting position of the type carriers 2 in question and thereby the types are caused to strike against the writing sheet 340 indicated by a dash-dotted line. An inked ribbon (not shown) is to be placed in usual manner between the types and the written sheet.

Subsequent to the printing the printing mechanism again is swung to the lower end position of its swing as shown in H6. 6 and simultaneously the setting bridge 4 with the rod 4b returns the printing hammers 19 to their cocked positions in which they are hooked up by the spring-loaded hooking bail 21. Said bail abuts to a lower portion of the cam disk 24 after the printing hammers have arrived at their cocked positions. After completed printing also the arms 9 are returned to their cocked positions shown in FIG. 4 by action of the resetting bail 11 controlled by action of the cam disks 12, the latches 7 thereby being moved out of engagement with the cogs 2f of the type carriers. in connection therewith and simultaneously with the cocking of the printing hammers 19 also the type carriers 2 are returned to their starting positions by action of rod 4a of the setting bail 4, which rod thereby cooperates with the stop surface on each of the type carriers. While the printing hammers 19 are cocked and the type carriers 2 are reset also the position transmitter 41 is returned to the upper end position of its swing shown in FIGS. 5 and 7. When the printing mechanism in this way has reassumed its starting position, the drive shaft 23 and thereby the shaft 13 which have carried out each its revolution are stopped, the starting and stopping of the drive shaft 23 preferably being effected by means of a coupling (not shown) by which the drive shaft 23 can be coupled to an electromotor (not shown) or the like. For service and overhaul of a printing mechanism of the aforedescribed type, the mechanism very easily can be removed from the machine in question by loosening the studs 33 screwn in whereby the link arms 31 are released, and by loosening the holding members 35 from the end wall plates 14 of the printing mechanism. If the printing mechanism entirely is to be removed from the machine, also a cable (not shown) intended for the electromagnets 39, the tube lamp 42 and the photodiodes or the like 44, must be disconnected, which very simply can be done while it is connected to the machine, by a multipole plug or the like.

The invention, of course, is not restricted to the embodiments described above and illustrated in the drawing, but can to its details be varied within the scope of the inventive idea.

What 1 claim is:

1. Printing apparatus for applying printed characters to paper or the like, said apparatus comprising:

a movable housing;

a plurality of type carrying members pivotally connected to said housing, each of said members'having a substantially sector-shaped portion and an arm portion extending substantially radially from said sector portion;

ratchet means forming part of each of said sector portions for interrupting movement of respective ones of said members;

a plurality of type members mounted on each of said sector portions and movable generally radially in the region of the circumference of said portion;

a plurality of printing hammers pivotally connected to said housing, each of said hammers being associated with one of said type carrying members; and

means for controlling the movement of said hammers to cause said hammers to engage selected ones of said type members, thereby to move said ones of said types into printing position.

2. Apparatus as in claim 1 wherein said ratchet means comprises a plurality of inclined teeth on the inner perimeter of said sector portion.

3. Apparatus as in claim 2 further comprising, a plurality of pawl members connected to said housing, each of said pawl members being movable to engage said inclined teeth of corresponding ones of said sector portions and a plurality of locking members, each of said locking members being engageable with one of said pawls to predispose said pawl for engagement with selected ones of said teeth.

4. Apparatus as in claim 3 further comprising, a plurality of dog members, each of said dog members being pivotally connected to one of said type-carrying members and biased in one direction, and first bridging means for simultaneously positioning each of said type-carrying members, said dog members being adapted releasably to engage said bridging means.

5. Apparatus as in claim 4 wherein said controlling means comprises spring means for biasing each of said hammers in the striking position relative to said type members, and latching means forming part of said first bridging means for releasably engaging each of said hammers to move said hammers against the bias of said spring means.

6. Apparatus as in claim 5 wherein, with respect to each of said type carrying members, said arm portion, said inclined teeth, said pawl and said locking members are substantially coplanar.

7. Apparatus as in claim 6 wherein, with respect to each of said type carrying members, said dog member and said printing hammer are substantially coplanar.

8. Apparatus as in claim 7 wherein each of said locking members is pivotally mounted relative to its corresponding pawl member, and comprises first and second surfaces for engaging said pawl, said first surface being eccentric relative to the pivot point of said locking member whereby one end of said surface is radially farther from said pivot point than other parts of said first surface.

9. Apparatus as in claim 8 further comprising second bridging means simultaneously engageable with each of said locking members for setting said locking members to a first position whereby said second surface engages said pawl to move said pawl out of engagement with said ratchet teeth, each of said locking members being spring biased to a second position in which said second surface is at least partially disengaged from said pawl whereby said pawl engages said ratchet teeth.

10. Apparatus as in claim 9 further comprising electromag netic means for actuating each of said locking members.

11. Apparatus as in claim 10 wherein said pawl members and said second bridging means are pivotally mounted about a common axis.

12. Apparatus as in claim 11 wherein said printing hammers are pivotally mounted about said common axis.

13. Apparatus as in claim 12 wherein said latching means comprises a latching member pivotally mounted relative to said hammers and simultaneously engageable with a portion of each of said hammers, said latching member being movable into and out of the path of motion of said hammers.

14. Apparatus as in claim 13 further comprising means for moving said housing into at least three positions relative to the paper, one of said positions being a printing position.

15. Apparatus as in claim 14 wherein said moving means comprises a first rotatable shaft connected to said housing.

16. Apparatus as in claim 15 wherein said moving means further comprises, a second rotatable shaft connected to said housing, and means connecting said first and second shafts for transmitting movement of one of said shafts to the other of said shafts, said second shaft having a first eccentric member mounted thereon and connected to said housing to induce oscillatory movement of said housing between said three positions.

17. Apparatus as in claim 16 further comprising a second eccentric member mounted on said second shaft and connected to said first bridging means to induce oscillatory movement in said bridging means simultaneously with said oscillator movement of said housin 8. Apparatus as in claim 7 further comprising a plurality of restraining bails, each of said bails being engageable with one of said hammers, and a plurality of cam members connected to said second shaft, each of said cam members being engageable with corresponding ones of said restraining bails for moving said bails selectively into and out of engagement with said hammers.

19. Apparatus as in claim 18 further comprising a cam member periodically engageable with said second bridging means to actuate said locking members.

20. Apparatus as in claim 19 wherein each of said restraining bails is pivotally mounted on said first shaft.

21. Apparatus as in claim 20 wherein said housing is adapted for lateral movement along said first shaft.

22. Apparatus as in claim 21 further comprising carriage means having first bearings connected to said first shaft and second bearings concentric with said first bearings for the pivotal bearing of said housing.

23, Apparatus as in claim 22 further comprising an elec tronic storage register to emit electric impulses for actuating said electromagnetic means, a code member movable synchronously with said first bridging means and having a plurality of machine readable code configurations, each of said configurations corresponding to one type position of said type carrying members, and means for scanning said code configurations, said scanning means being adapted according to a scanned code to emit an electric signal for sensing said storage register with respect to the presence of a corresponding character registration.

Claims

1. Printing apparatus for applying printed characters to paper or the like, said apparatus comprising: a movable housing; a plurality of type carrying members pivotally connected to said housing, each of said members having a substantially sectorshaped portion and an arm portion extending substantially radially from said sector portion; ratchet means forming part of each of said sector portions for interrupting movement of respective ones of said members; a plurality of type members mounted on each of said sector portions and movable generally radially in the region of the circumference of said portion; a plurality of printing hammers pivotally connected to said housing, each of said hammers being associated with one of said type carrying members; and means for controlling the movement of said hammers to cause said hammers to engage selected ones of said type members, thereby to move said ones of said types into printing position.

10. Apparatus as in claim 9 further comprising electromagnetic means for actuating each of said locking members.

17. Apparatus as in claim 16 further comprising a second eccentric member mounted on said second shaft and connected to said first bridging means to induce oscillatory movement in said bridging means simultaneously with said oscillatory movement of said housing.

18. ApparatUs as in claim 17 further comprising a plurality of restraining bails, each of said bails being engageable with one of said hammers, and a plurality of cam members connected to said second shaft, each of said cam members being engageable with corresponding ones of said restraining bails for moving said bails selectively into and out of engagement with said hammers.

23. Apparatus as in claim 22 further comprising an electronic storage register to emit electric impulses for actuating said electromagnetic means, a code member movable synchronously with said first bridging means and having a plurality of machine readable code configurations, each of said configurations corresponding to one type position of said type carrying members, and means for scanning said code configurations, said scanning means being adapted according to a scanned code to emit an electric signal for sensing said storage register with respect to the presence of a corresponding character registration.