US3772989A

US3772989A - Planetary drum printer with movable gear segments to control type carrier rotation

Info

Publication number: US3772989A
Application number: US00241913A
Authority: US
Inventors: G Burkhardt; A Metschnabl
Original assignee: Diehl GmbH and Co
Current assignee: Diehl Verwaltungs Stiftung
Priority date: 1971-04-08
Filing date: 1972-04-07
Publication date: 1973-11-20
Anticipated expiration: 1990-11-20
Also published as: DE2117336B2; SE367785B; GB1331008A; IT951220B; DE2117336C3; FR2136246A5; DE2117336A1; CH551048A

Abstract

Roller printer, especially for data processing machines, in which a rotatable drum has axial rods rotatable therein and circumferentially spaced near the periphery of the drum, each rod has a raised type element thereon to roll over a member to be printed thereon by rotation of the rod in a printing region. Each rod has an external gear segment thereon and an internal gear segment concentric with the drum is arranged to mesh with the external gear segments. A pawl is provided which is selectively operable to initiate rotation of the rods near the printing region to cause meshing of the external gear segments with the internal gear segment. The pawl is normally latched out of effective position by a latch lever arrangement and electromagnetic means connected to the latch lever arrangement is energizable for selectively moving the latch lever to release the pawl for movement into effective position.

Description

United States Patent 1 Burkhardt et al.

[ Nov. 20, 1973 PLANETARY DRUM PRINTER WITH MOVABLE GEAR SEGMENTS TO CONTROL TYPE CARRIER ROTATION [75] Inventors: Gottfried Burkhardt, Winkelhaid;

Andreas Metschnabl, Numberg, both of Germany [73] Assignee: DIEI-IL, Nurnberg, Germany [22] Filed: Apr. 7, 1972 [21] Appl. No.: 241,913

[30] Foreign Application Priority Data Apr. 8, 1971 [52] US. Cl. 101/110, 101/77 Germany P 21' 17 336.4

7/1964 Howard 101/110 X 7/1969 Huber lOl/llO X [5 7 ABSTRACT Roller printer, especially for data processing machines, in which a rotatable drum has axial rods rotatable therein and circumferentially spaced near the periphery of the drum, each rod has a raised type element thereon to roll over a member to be printed thereon by rotation of the rod in a printing region. Each rod has an external gear segment thereon and an internal gear segment concentric with the drum is arranged to mesh with the external gear segments. A pawl is provided which is selectively operable to initiate rotation of the rods near the printing region to cause meshing of the external gear segments with the 12 Claims, 7 Drawing Figures PATENTEU NOV 2 0 I973 SHEET 2 EF 3 PLANETARY DRUM PRINTER WITH MOVABLE GEAR SEGMENTS TO CONTROL TYPE CARRIER ROTATION The present invention relates to a roller printer for data processing machines with a continuously rotating type drum on which are rotatably joumaled toothequipped type elements which by a positive engagement with a control means roll on a printing station.

A printing principle of the above mentioned type has been disclosed in German patent No. 1,270,854, according to which the printing operation is carried out by combined rolling movements of a reversible pinion and of a type element cooperating therewith, said printing operation being forced during the rotation of the drum. The roller movement of the reversible pinion is effected on a gear segment which is displaceable radially with regard to the drum and which is stationarily arranged in the interior of the drum and is adapted to be actuated directly by an electromagnet. The rolling movement of the type element occurs at the printing station of the printing support. For returning the type element, there is provided a spring.

This printing principle will, in order to be able safely to control such type elements and reversing pinion, require a construction of a relatively large size, which is due to the meshing length of the displaceable gear segment. In connection therewith, with this control manner it is possible to obtain the high printing speed meeting modern requirements only using relatively complicated constructions.

It is, therefore, an object of the present invention to provide a simpler and more compact roller printer with a type drum which will make it possible with a high number of types, for instance, 45 types, to print on an average 15 characters per second.

These and other objects and advantages of the invention will appear more clearly from the following specification, in connection with the accompanying drawings, in which:

FIG. 1 illustrates a typedrum for a series printer with a printing roller.

FIG. 2 is a partial section through an individual type element of FIG. 1 with pawl.

FIG. 3 shows an electromagnet with scissors-shaped actuating mechanism for the pawl of FIG. 2.

FIG. 4 shows the pawl of FIGS. 1 to 3 in operative position as seen from above.

FIG. 5 shows type elements with a dish section.

FIG. 6 illustrates a type drum with an alpha numerical printer.

FIG. 7 shows a portion of the printer of FIG. 1 with interengaging parts to facilitate understanding of the operation thereof.

The roller printer for data processing machines is characterized in that each type element has associated therewith a gear segment which when controlling the type element by a pawl-shaped control means meshes with an inner gear segment that is associated with the printing area and rests relative to the type drum.

To this end the gear segment may be equipped with a guiding section formed by a missing tooth. This guiding section will directly after an effected meshing of the gear segment with the inner gear segment abut a guiding surface which rests relative to the type elements, said guiding surface arresting the type element in its starting position. I

The printing device according to the invention may advantageously be composed of a few and simple elements in order positively to control all movement sections, namely, the rolling of the printing type and the returning of the type element. The type elements may thus be arranged closely adjacent in the type drum in view of the pawl requiring only a slight engaging width, so that the type drum may have only a small diameter.

According to a further embodiment of the present invention, the gear segments of adjacent type elements having the shape of shafts may be axially offset relative to each other so that adjacent gear segments will partially overlap each other in the type drum. As a result thereof, an even closer adjacent arrangement of the type elements and thus an extremely short drum diameter of low circumferential speed will be made possible.

According to a further development of the invention, the tooth spaces of the inner gear segment are arranged in a dish extending around the type drum, which dish by means of a guiding surface positively guides the type elements through the intervention of their guiding section during the rotation of the type drum in its rest position. In this way, a positive guiding of the type element until the selection of the type element for roller printing, and a likewise positive return to its starting position will be made possible. I

For a series printer, according to a further development of the invention, printing types may be arranged below an upper plate of the type drum on the type shafts.

For an alpha-numerical printer with which each print is to be visible immediately, it is suggested according to a further feature of the present invention to provide printing types which are arranged on the type shafts above an upper plate of the type drum. Between the type shafts arranged in the type drum there are provided gaps so that a printed type can without delay be recognized in view of a stroboscope-like effect of the rotating type drum.

For controlling the type element, there may be employed, a pawl which is controllable by an electromagnet and which is provided with a double-forked end face toward the type element. From said end, a wedgeshaped pawl end is, for initiating the rolling of the type element, adapted to be moved or pivoted into the path of a control means in the form of a control tooth whereas the pawl is adapted by the other blunt pawl end to be returned by an abutment immediately after the pivoting movement, said abutment being arranged on the type element and being angularly offset relative to the control tooth. The wedge-shaped pawl end advantageously assures the timely engagement for selecting type to be printed. A faulty type selection as it is possible with the heretofore known printer by belatedly controlling or controlling the reversing pinion or holding the latter for too long a time is practically completely eliminated by the arrangement according to the invention. The return of the pawl is brought about by the turning movement of the type link. Therefore, no return spring is necessary in contrast to the heretofore known printer.

For assuring a safe operation, the printer according to the present invention is, according to a further development of the invention, equipped with an electromagnet which pivots a scissor-like element in such a way that the pawl is pivoted by a spring into the path of the control gear to be controlled in order subsequently to arrest the pawl in its starting position after it has been ejected or relieved by a second scissor-shaped element. In this way, it will be assured that already an energization of the electromagnet will suffice to release the pawl which then independently of a possible timely delayed withdrawal of the armature is, by the second scissor-shaped element, secured in its starting position already prior to the starting position of the armature being reached.

Referring now to the drawings in detail, according to FIGS. 1 and 2 a type drum 1 comprises an upper plate 2 and a lower plate 3 between which at the circumference, type shafts 4 are rotatably joumaled. The type drum 1 is connected to a shaft 6 which in a nonillustrated manner is joumaled in the frame 5, for instance, of a writing carriage. Screwed onto the frame by means of supports 7' is a dish 7 which comprises the type basket 1 within the range of gears 8 (FIG. 2) of the type shaft 4. Within the range of a printing roller 9, the dish 7 has an inner gear segment 10 with five tooth spaces 11. Thus, the gear drive 8 has five teeth 12 l6 and a guiding section 17 formed by a missing tooth. On the type shaft 4 shown by way of example in FIG. 2 there is provided an elevated type 18.

For frictional or positive holding of the type shaft in its starting position there is provided a leaf spring 21 which is fastened to the upper plate 2 and engages a cam of the type shaft 4. A pawl 23 which by means of a pivot 22 is pivotally mounted in the frame 5 has that end thereof which faces the type shaft 4 provided with a double fork-shaped portion. Its upper wedgeshaped pawl end 24 cooperates with a control tooth 25 which is arranged on the type shaft 4, whereas the lower blunt pawl end 26 is adapted to be actuated by an abutment surface 27 of the type shaft 4.

FIG. 3 shows the electromechanical operation of the pawl 23. An armature 28 of an electromagnet 29 is, by means of a pivot 31, linked to a power pivotable scissor-shaped element 30. The lower element 30 keeps by means of a nose 32 a downwardly angled-off pawl end 33 in its rest position against the thrust of a spring 34. An upper scissor-shaped element 35 has its nose 36 spring biased by a spring 37 and rests on the back side of the pawl 33. The angled-ofi' pawl end 33 is pivotable within the range of a recess 38 of the frame 5. A return spring 39 is provided for the lower link 30.

FIG. 4 shows the working position of the pawl 23 which is controlled by the energization of the electromagnet which pivotally controls the lower link 30. The angled-off link end 33 is pivotable in clockwise direction by the spring 34 and engages the upper end of the recess 38 of the frame 5. The wedge-shaped pawl end 24 catches behind the control tooth 25.

According to FIG. 5, the gears 8', 8", 8" of adjacent type shafts 4", 4", 4" are axially offset with regard to each other. Correspondingly, the guiding surface 40' of the dish 7' with the tooth spaces 11 has at least double tooth thickness of the transmission 8 8".

FIG. 6 shows type shafts of which only two type shafts 42, 43 are shown in order to simplify the figure. These type shafts are rotatably joumaled in an upper plate 44 and in a lower plate 45 of a type drum 46. Printing types 47(A), 48 (F) are arranged on those ends of the type shafts 42, 43 which protrude beyond the upper plate 44.

If a print of a type is to be made, the electromagnet '29 is actuated by a pulse of a commercially customary electronic control. The type drum 1 will in these circumstances be in a continuously uniform rotation. The pawl 23 is released by the scissor-shaped link 30 which is operable in the direction of the arrow by the armature 28, and actuated by the thrust of spring 34 drops in front of the control tooth 25 of the transmission to be selected. The wedge-shaped pawl end 24 will now in the course of the further rotation of the type drum 1 turn the control tooth 25 as a result of which the type shaft 4 rotates about its axis, and the tooth 12 drops into the respective adjacent first tooth space 11. The continuous rotation of the type drum 1 brings about the complete rolling or development of the gear 8 in the inner gear segment 10 by an angle of 360 and thus the rolling or development of type 18 on a sheet, plate, or the like 41 on the printing roller 9. After the fifth tooth 16 of the transmission 8 pivots out of the last one of the tooth spaces 11, tooth l2 abuts the guiding surface 40 of the dish 7. As a result thereof, the type shaft 4 is again arrested in its starting position aided by the leaf spring 21. The return of the pawl 23 is effected shortly after the start of the rotation of type shaft 4. The blunt pawl end 26 is pushed back in counterclockwise direction by the abutment surface 27 of the type shaft 4. The upper scissor-shaped link 35 will by means of its nose 36, in case of the link 30 being returned too late, catch the angled-off pawl end 33 of pawl 23 in its starting position. In the course of the withdrawal of the lower link 30 by the electromagnet 29, the upper link 35 frees the link 23 for engagement with the nose 32 of the lower link 30. The starting position of the pawl as shown in FIG. 3 is thus again restored.

In supplementing the above embodiment, it is also possible for damping the noise developed when selecting the respective type element for printing purposes, advantageously slightly resiliently to journal the inner gear segment or the dish 7 relative to the frame 5. To this end, the dish 7 may be connected to frame 5 by means of suitably shaped rubber bodies.

As a record carrier there may be employed print sensitive paper. On the other band, also a colored band may be employed which is guided at the printing place between the.printing types and the printing roller or a customary paper band as record carrying means.

The operation of the device may best be understood from FIG. 7 in which the lever 30 engages the pawl lever portion 33 by means of nose 32 when lever 30 is pivoted in the direction of the arrow A in response to the energization of the electromagnetic means, nose 32 will release the pawl lever 30 to the influence of its spring 34. When the pawl lever is cammed back by its cam end 26, if lever 30 has not yet returned, the lever 35 engages part 33 of the pawl lever 30 by nose 36.

Nose 36 is offset from nose 32, and when lever 30 returns, an abutment element B thereon pushes lever 35 back so that nose 36 leaves portion 33 of the pawl lever 30 and releases portion 33 to drop against nose 32 of lever 30.

It is, of course, to be understood that the present invention is, by no means, limited to the particular constructions shown in the drawings, but also comprises any modifications within the scope of the appended claims.

What is claimed is:

1. In a roller printer, especially for a data processing machine; a frame, a rotatable drum in the frame, a printing region in the frame disposed in a predetermined circumferential position relative to the axis of the drum, a plurality of rods extending axially of said drum and in circumferentially spaced relation near the periphery of the drum and rotatable on the drum, each rod having a type element thereon operable to print on a member in said printing region and over which member the type element is adapted to roll, an external gear segment on a first peripheral portion of each rod, a second peripheral portion of each said rod being free of any external gear segment, an internal gear segment in the frame within the axial range of said external gear segments and within the circumferential range of said printing region and coaxial with said drum but out of circumferential range of said second peripheral portion of said rod, biasing means normally biasing said external gear segments into such rotated position as to pass idly by said internal gear segment during rotation of said drum with the related rod in such rotated position that said type element remains out of engagement with a member in said printing region, and control means adjacent said printing region actuatable for causing a said external gear segment to mesh with said internal gear segment as said drum rotates and carries the respective rod past said printing region thereby to cause the rod to rotate and roll the type element thereon on a member in said printing region and print thereon.

2. A roller printer according to claim 1 in which each rod has a control element and in which said control means includes a pawl lever mounted in said frame and moveable upon actuation into engagement with the control element pertaining to the external gear segment which is to mesh with said internal gear segment.

3. A roller printer according to claim 1 in which each external gear segment is in the form of a gear with a missing tooth, an internal guiding surface coaxial with said drum, each external gear segment upon disengagement from said internal gear segment being in such rotated position that the teeth on opposite sides of said missing teeth engage said guiding surface and hold the respective rod against rotation in said drum.

4. A roller printer according to claim 1 in which the said external gear segments of adjacent ones of said rods are in axially ofiset overlapping relation.

5. A roller printer according to claim 1 in which said internal gear segment is formed in a ring coaxial with said drum and comprise a predetermined number of tooth spaces, each external segment comprising the same number of teeth as said number of tooth spaces and a gap formed by a missing tooth, the teeth of said external gear segment on opposite sides of said gap cooperating with the untoothed portion of the inner periphery of said ring to hold the respective rod in a predetermined position on the drum as the drum rotates and carries the rod along said untoothed portion of the inner periphery of said ring.

6. A roller printer according to claim 1 in which said drum has axially spaced plates in which said rods are journalled, said type elements being carried by said rods on the side of one of said plates opposite the other said plate.

7. A roller printer according to claim 1 in which said drum has axially spaced plates in which said rods are joumaled, said type elements being carried by said rods between said plates.

8. A roller printer according to claim 2 in which said pawl lever is pivoted in said frame and has a first pawl end engageable with the control element of a said rod upon actuation of the pawl lever whereby rotation of said drum causes the respective rod to turn and bring the external gear segment pertaining thereto into mesh with said internal gear segment, said pawl lever having a second pawl end, and cam means on said rod engageable with said second pawl end when said rod rotates due to engagement of the external gear segment thereon with said internal gear segment, said cam means being operable to move said pawl lever back to nonactuated position wherein said first pawl end is outside range of said control elements.

9. A roller printer according to claim 8 in which said pawl lever is spring biased toward control element engaging position, a latch lever pivoted in said frame and having a nose engageable with said pawl lever when the pawl lever is in retracted position and spring urged toward pawl lever engaging position, and electromagnetic means connected to said latch lever energizable for withdrawing said latch lever from engagement with said pawl lever.

10. A roller printer according to claim 9 which includes a second latch lever having a nose engageable with said pawl lever in the retracted position of the pawl lever and operable to hold said pawl lever in retracted position prior to the first mentioned latch lever returning to pawl lever engaging position following energization of said electromagnetic means.

11. A roller printer according to claim 10 in which the nose on the first mentioned said latch lever is offset from the nose on said second latch lever in the direction in which the region of said pawl lever engaged by said noses moves when the pawl lever is released to the influence of the biasing spring therefor, and means for disengaging said second latch lever from said pawl lever when the first mentioned latch lever returns to pawl lever engaging position.

12. A roller printer according to claim 3 in which the control element on each rod is in the form of a tooth axially spaced from the external gear segment on the respective rod and circumferentially located on the rod to align with the missing tooth on the respective rod.

' =0 II t i

Claims

4. A roller printer according to claim 1 in which the said external gear segments of adjacent ones of said rods are in axially offset overlapping relation.

7. A roller printer according to claim 1 in which said drum has axially spaced plates in which said rods are journaled, said type elements being carried by said rods between said plates.