EP0174381A1 - Print hammer bank of modular construction - Google Patents

Abstract

Tongue-shaped plungers are used as pressure hammers, which have a plurality of anchor webs which, when electromagnets are excited, pull magnetic working gaps assigned to them. The working gaps for print hammers 5, 6 arranged next to one another are formed between mutually aligned pole faces by electromagnets of an upper (3) and lower (4) row of modules. The rows of modules consist of modules (7, 8, 9, 10) of the same geometric shape and structure that lie side by side. In each module, the adjacent electromagnetic units (wider than the print hammers) are offset from each other for packing reasons, which also results in a mutual offset of the anchor bars in adjacent print hammers. The modules have a parallelogram-like shape - the number of print hammers per module is even.

Description

The invention relates to a print hammer bank in a modular design for known electromagnetic print hammer drives of the type described in the preamble of claim 1.

These electromagnetic pressure hammer drives are based on the principle described in European patent application 80 103 387.9 in connection with FIGS. 1 a, 1 b, 2, 3, 4 and 6. This application relates to a fast electromagnetically actuated plunger drive, which can be used in particular for impact printers. The electromagnet basically consists of essentially symmetrically constructed magnetizable yoke halves with a corresponding excitation coil (s). The facing pole ends of the yoke halves form aligned magnetic working gaps. A plunger which is displaceable in the direction of the alignment line of the working gaps is arranged between the magnetic working gaps. The cross section of the ram is adapted to the area of the working column. It can have a cylindrical or cuboid shape. It contains, for example, (disc or) cuboid anchor elements made of magnetizable material and spacing elements made of predominantly non-magnetizable material arranged between them. The anchor elements have such a geometric design that their volume is in the order of the working gap volume. In the starting position of the plunger, the armature elements are essentially in front of the working gaps when the electromagnets are not excited. When the electromagnet is excited, they are drawn into this working column and he drive an acceleration. In arrangements of this type, the plunger moves in a straight line.

A distinction is made between cylinder-shaped and tongue-shaped plungers in print hammer drives of this type.

Tongue-shaped plungers come into consideration for the present invention.

• Aufwendige Herstellung, komplizierte Auswechselbarkeit der Stößeleinheiten und Schwingungsanfälligkeit.

The European patent application 82 101 861.1 (GE 980 052E) describes a bench for accommodating ram units lying next to one another. These each consist of a flat, narrow frame. A tongue-shaped tappet, which is driven by an electromagnetic drive unit, runs within a recess in the frame. For receiving and guiding the individual plunger units, the bench comprises a receiving rail and a comb-like holding rail, between which the frames are arranged. Attachments of the lower frame parts can be received by slots in the receiving rail. The upper frame parts are held in incisions in the comb-like holding rail. The tongue-shaped plungers are guided laterally through the electromagnetic drive units arranged on both sides of the frame and aligned with one another. Such a print hammer bank has a number of disadvantages:

• Elaborate production, complicated interchangeability of the tappet units and susceptibility to vibration.

It is therefore an object of the invention to provide a print hammer bank in a modular design to avoid these disadvantages.

This object is achieved by the measures mentioned in the characterizing part of claim 1. Then modules of identical shape are used to form the print hammer bank. These modules have a high packing density for electromagnetic units. The identical form of the modules (under supervision) is based on a modified parallelogram. Each module, encapsulated in plastic, has pole faces of electromagnetic yokes arranged in columns. The magnetic working gaps are formed between the aligned pole faces of the modules of an upper row of modules and the modules of a lower row of modules. Adjacent modules are interlocked. A tongue-shaped plunger (pressure hammer) is assigned to each gap in the modules. Each print hammer has a series of anchor bars. Each tie bar is assigned to a working gap. A working gap is formed between a pole face of a module in the upper row of modules and the pole face of a module in the lower row of modules. For reasons of a high packing density, the electromagnetic units for pressure hammers lying next to one another are arranged offset in the modules. This also results in a mutual offset of the anchor webs of adjacent pressure hammers.

If the plastic in which the modules are cast is made of a good heat-conducting material, there is very good heat dissipation in the pressure hammer bank.

Advantageous developments of the invention can be found in the subclaims.

An embodiment of the invention is shown in the drawings and will be described in more detail below.

• Fig. 1 eine schematische perspektivische Darstellung einer Explosionszeichnung der unteren und oberen Modulreihe der Druckhammerbank mit dazwischen nebeneinander angeordneten Druckhämmern;
• Fign. 2A eine schematische perspektivische Dar-und 2B stellung einer Modul-Basisplatte, wobei
• Fig. 2A die den Druckhämmern zugewandte Seite und
• Fig. 2B die den Druckhämmern abgewandte Seite zeigt;
  (Fig. 2B versteht sich als Darstellung der um 180° um die Achse 1 gedrehten Modul-Basisplatte nach Fig. 2A.)
• Fign. 3A eine Aufsicht auf in der Druckhammerbank und 3B nebeneinanderliegende Druckhämmer, bei denen die für den Antrieb wirksamen Ankerstege gegeneinander versetzt sind;
• Fig. 4 eine schematische perspektivische Darstellung einer Explosionszeichnung der Elektromagnetspuleneinheit, bestehend aus zwei U-förmig nebeneinander angeord- . neten Jochen, deren benachbarte Schenkel von einer Spule umfaßt werden;
• Fig. 5 zwei nebeneinanderliegende Modul-Basisplatten der oberen Modulreihe in perspektivischer Darstellung mit einem Blick auf die den Druckhämmern zugewandte Seite;
• Fig. 6 zwei nebeneinanderliegende Modul-Basisplatten der unteren Modulreihe in perspektivischer Darstellung mit einem Blick auf die den Druckhämmern zugewandte Seite;
  (Bei der zusammengebauten Druckhammerbank kann man sich die Modul-Basisplatten gemäß Fig. 5 um 180° um die gedachte Achse 2 derart gedreht denken, daß zwischen den Modul-Basisplatten nach -Fig. 5 (gedreht) und denen nach Fig. 6 ein Abstand zur Aufnahme der Druckhämmer bleibt.)
• Fig. 7 eine ausschnittsweise schematische perspektivische Darstellung eines zwischen der oberen und unteren Modulreihe liegenden Druckhammers.

Show it:

• Figure 1 is a schematic perspective view of an exploded view of the lower and upper row of modules of the print hammer bank with print hammers arranged next to each other in between.
• Fig. 2A shows a schematic perspective illustration and FIG. 2B shows a module base plate, wherein
• 2A the side facing the print hammers and
• 2B shows the side facing away from the printing hammers;
  (FIG. 2B is a representation of the module base plate rotated by 180 ° about axis 1 according to FIG. 2A.)
• Fig. 3A shows a plan view of printing hammers lying next to one another in the printing hammer bank and FIG.
• Fig. 4 is a schematic perspective view of an exploded view of the electromagnetic coil unit, consisting of two U-shaped arranged side by side. neten yokes, the adjacent legs of which are enclosed by a coil;
• 5 shows two side-by-side module base plates of the upper row of modules in a perspective view with a view of the side facing the print hammers;
• 6 shows two side-by-side module base plates of the lower row of modules in a perspective view with a view of the side facing the pressure hammers;
  (In the assembled print hammer bank, one can think of the module base plates according to FIG. 5 rotated by 180 ° about the imaginary axis 2 such that there is a distance between the module base plates according to FIG. 5 (rotated) and those according to FIG. 6 remains to accommodate the print hammers.)
• Fig. 7 is a fragmentary schematic perspective view of a print hammer located between the upper and lower row of modules.

Fig. 1 shows a schematic perspective view of an exploded view of the lower and upper Row of modules of the print hammer bench with print hammers arranged side by side in between.

Modules 7, 8, 9, 10 of identical form are used to form the print hammer bank. Adjacent modules 9 and 10 form an upper row 3 of the print hammer bank and adjacent modules 7 and 8 form a lower row 4 of the print hammer bench. The upper 3 and lower 4 row of modules are spaced apart. Between them are pressure hammers arranged side by side, of which only two, 5 and 6, are shown in FIG. 1. The direction of action of the print hammers is indicated by the arrow direction D. Each module 7, 8, 9, 10 has a plurality of pole faces PF of electromagnetic yokes on the side facing the pressure hammers. The pole faces of the upper row of modules are aligned with the pole faces of the lower row of modules. A large number of magnetic working gaps are defined by the spaced pole faces of the upper and lower row of modules. These working gaps are activated by an appropriate electromagnetic coil excitation.

The pole faces are arranged in columns (C). In Fig. 1, each column of a module has four pole faces. The print hammer (detailed illustration in FIGS. 3A and 3B) has as many soft iron webs (anchor webs) as there are working gaps defined by pole faces in the column assigned to it; in the given embodiment also four pieces. The distance between the soft iron bars in a print hammer corresponds to the distance between the working columns in the corresponding column of the print hammer bank. In the rest position of the print hammer, its soft iron bars are in front of the working columns assigned to them, which are formed by opposite pole faces of the modules.

When the magnetic working column for a printing hammer is activated, the anchor webs of the printing hammer are drawn into the working column and accelerated, so that the printing hammer undergoes a drive movement in the printing direction D. The modules of a row of modules are interlocked. The upper 3 is spaced from the lower 4 module row by appropriate spacing elements to form the working gaps. The modules of the top 3 and bottom 4 rows are held together by appropriate screw, rivet or similar connections. Such connections can e.g. through the through-holes marked P1 / P2, P3 / P4, P5 / P6, P7 / P8. A large number of connections 46 for the electromagnetic units are provided on the side of the modules facing away from the pressure hammers. The following details are given about details of the electromagnetic units, the spacing elements for the module rows, the positive connection of the modules within a module row and about the structure and structure of the modules.

The column boundary identified by 72 is described in detail in connection with FIG. 7.

A module consists of a module base plate (for example 11 in the case of module 7) and a part 12 connected to it, in which the electromagnet units 30 (FIG. 4) are arranged or cast with it. As already mentioned, adjacent modules are positively connected to each other in the print hammer bank. The pole faces of the modules are arranged in columns (C in Fig. 1). A print hammer is assigned to each column.

For reasons of tight packing, the electromagnetic units for adjacent module gaps are offset from one another.

Seen from above, the identical form of the modules is based on a modified parallelogram. It permits a close packing density of the side-by-side pressure hammers, the anchor webs of which are also offset from one another in accordance with the pole faces (or electromagnet units) which are offset from one another in adjacent columns. If all modules of the print hammer bank are identical in shape, both in the upper and in the lower module row, the number of print hammers per module is always even.

FIG. 4 shows a schematic perspective illustration of an exploded drawing of a magnet coil unit. It consists of two yokes 31 and 32 arranged next to one another in a U-shape, the adjacent legs of which are encompassed by a common coil 45. The coil carrier consists of a diamond-shaped base plate 50 and an upper cover plate 49. Both plates are connected to one another by two spacer elements 48 and a centrally arranged hollow body 51. The spacer elements 48 are connected beyond the base plate to contact pins 46 for the electrical connections of the coil 45. The base plate 50 has openings 74 and 75 for the passage of the outer yoke legs of the pair of yoke legs 31, 32 and an opening in the region of the hollow body 51 for receiving the adjacent yoke legs of the pair of yoke legs 31, 32. There are four in the cover plate 49 Openings 41, 42, 43, 44 are provided for receiving the leg ends of the yokes 31 and 32. After inserting the yokes into the coil former and then fixing them, for example by casting in plastic, the yoke ends protrude somewhat above the upper cover plate 49.

The following describes how the electromagnetic units and the module base plates are connected to each other.

The figures 2A and 2B show a schematic perspective illustration of a module base plate, FIG. 2A showing the side facing the print hammers and FIG. 2B showing the side facing away from the print hammers. FIG. 2B is understood to be a representation of the module base plate according to FIG. 2A rotated through 180 ° about axis 1. While a perspective top view of the module base plate is shown in viewing direction U in FIG. 2A, a top view of its underside in viewing direction B can be seen in FIG. 2B. The pole faces in a column are formed by the four ends of the yokes of a pair of magnetic yokes 31, 32. These ends are labeled 31-1, 31-2, 32-1 and 32-2 in Fig. 4. The electromagnet units are plugged on with the top surface 49 first on the back of the module base plates in direction B, so that the yoke ends 31-1 to 32-2 in slightly protruding from the openings 41, 42, 43 and 44 beyond the top surface 49 of the electromagnet unit the openings corresponding to them (the pole faces in the openings of the first and second column in FIG. 2A are designated with (32-1), (32-2), (31-1) and (31-2) corresponding to the pole ends of the electromagnetic unit ) fit a column in the module base plate. The yokes are inserted into these openings until their pole face ends with the plane of the module base plate. It should be noted repeatedly that an electromagnetic unit is provided for each module column.

For reasons of a high packing density, the electromagnetic units for module columns lying next to one another are arranged offset. As a result, the pole faces of adjacent module columns are also offset from one another. Two mutually offset electromagnet units are indicated in FIG. 2B by the contours of their cover plates arranged in broken lines.

5 shows two side-by-side module base plates of the upper row of modules in a perspective view with a view of the side facing the pressure hammers. The left base plate 9 has extensions 93 and 94 on its left side and cutouts 91 and 92 on its right side. For the right base plate 10, the extensions are marked with 103, 104 and the cutouts with 101 and 102. The extensions and recesses have such a shape that they fit into one another in a form-fitting manner.

6 shows two side-by-side module base plates 7 and 8 of the lower module row in a perspective view with a view of the side facing the pressure hammers.

In the assembled print hammer bank, the module base plates 9 and 10 according to FIG. 5 can be thought to be rotated by 180 ° about the imaginary axis 2 such that there is a distance between these module base plates in the rotated state and those 7, 8 according to FIG. 6 remains to accommodate the print hammers.

FIG. 7 shows a fragmentary schematic perspective illustration of a printing hammer lying between the upper and lower row of modules.

The section of the module in the upper row of modules is shown with 80, the one in the lower row with 70. The upper and lower row of modules are spaced apart from one another by spacers 83 running in grooves 82. The course of these spacers corresponds to the column boundaries indicated in FIG. 1 by simple lines. A print hammer is assigned to each column. 7 shows one of these print hammers and is identified by 71. The direction of action of the print hammer is indicated by the arrow D. Details of the print hammers are shown in FIGS. 3A and 3B. These figures show a top view of print hammers lying next to one another in the print hammer bank, in which the anchor webs effective for the drive are offset from one another.

The anchor webs of the pressure hammer 5 are identified by 51, 52, 53 and 54. They are assigned to the working columns, which e.g. are defined by the pole faces 32-1, 32-2, 31-1 and 31-2 (FIG. 2A) of a base plate of the upper module row and "of the pole faces aligned on these pole faces of a corresponding base plate of the lower module row. The same applies to the printing hammer 6 with the anchor bars 61, 62, 63, 64. These anchor bars are assigned to the pole faces 32-1, 32-2, 31-1, 31-2 of the second column in Fig. 2A. The pressure hammers 5 and 6 have recesses 55, 56, 66 and 65 to reduce their weight and are provided with print hammer heads 57 and 67 at their action ends.

The pressure hammers are returned in a conventional manner, e.g. by a leaf spring which engages in a suitable recess 55, 56 or 66, 65. In the above-mentioned recesses or at the ends of the print hammers opposite the print hammer heads 57, 67, damping elements can also expediently be provided for defining the starting position of each print hammer.

Claims (3)

1. pressure hammer bank in modular design for electromagnetic pressure hammer drives known per se, in which electromagnetically activatable magnetic working gaps are defined and a tongue-shaped element (plunger, pressure hammer) which is displaceable in the direction of the working gap is provided and which has anchor webs made of magnetizable material, of which each anchor web is assigned to a work gap,
in which the working gaps of opposing pole ends are each formed by excitation coils of magnetizable yoke halves and the anchor webs have such a geometric design that their volume is in the order of the working gap volume and the anchor bars in the starting position of the pressure hammer are in the non-excited state of the electromagnet in front of its working gaps and are pulled into its working gap when the electromagnet is excited,
characterized,
that the print hammer bank from a lower row (4) of adjacent modules (7, 8) and an upper row (3) of adjacent modules (9-10) of the same geometric shape and structure,
that between the lower (4) and upper (3) row of modules, working gaps for receiving adjacent pressure hammers (5, 6) are defined; the working gaps between opposing pole ends (31-1, 31-2; 32-1, 32-2: PF) of the modules of the lower and upper rows are formed,
that for side-by-side print hammers, the electromagnets assigned to them (with a greater width than the print hammers) are mutually offset within a module,
and that the modules have a shape similar to a parallelogram when viewed from the side facing the print hammer plane. 2. Arrangement according to claim 1,
characterized,
that the electromagnets (30) for each print hammer consist of two successive, spaced-apart U-shaped magnet yokes (31, 32) with a common coil (45) common to their adjacent legs (31-1, 32-2). 3. Arrangement according to claim 1,
characterized,
that each module consists of a base plate (11) facing the pressure hammer side and a body (12) connected thereto, in which the electromagnet units (30) are cast, and that the base plate has openings for receiving the pole ends of the yokes of the electromagnet units.

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