JPH0435175Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention is a wire support part that is made of an elastic body and moves the wire up and down with an armature in the printing head of a wire dot printer. It is about improvement.

[Prior Art] FIG. 7 is a partially cutaway sectional view of a print head of a conventional nine-dot wire dot printer. In the figure, reference numeral 1 denotes a core assembly, which is a main body, and has an annular permanent magnet 3 inside a cylindrical yoke 2 having a flange 2a and a hole (not shown) in the bottom.
and a plurality of electromagnets 4 (nine in the illustrated example). In the electromagnet 4, an exciting coil 4b is wound around a magnetic pole core 4a. 7 is the printing wire 16
and an armature 17, which moves the wire 16 up and down by moving the armature 17 up and down by turning the electromagnet 4 ON and OFF. Further, the flange 2a of the yoke 2
includes an auxiliary yoke 5, a first spring receiving member 6, a second spring receiving member 8, and a cover 9 having a printed nose 9a.
are mechanically positioned and mounted, respectively, and fixed to the flange 2a of the core assembly 1 with a plurality of fixing screws 10.

11 is a flexible wire, and electromagnet 4
A current is supplied to the excitation coil 4b according to the print signal.

Reference numeral 12 denotes a heat sink for discharging heat generated inside the core assembly 1 to the outside, and is made of a good heat conductive material such as aluminum. Part 2a
It is tightly fixed to the bottom of the core set 1 through the.

In recent years, there has been a trend toward miniaturization of printers, and as a result, miniaturization of print heads has become a necessary condition. Therefore, we reduced the length between the spring fulcrum 15 of the wire support part 7 and the wire 16 to reduce the size, and at the same time, made the vertical movement of the armature 17 lighter to improve followability while applying strong printing pressure to the wire 16. must be generated. For that purpose, 1
Since there is a limit to the number of thick spring members due to fatigue stress, for example, two thin spring members 7a and 7b may be used.
has been improved to use. Therefore, the wire support section 7 is constructed as shown in the plan view of FIG. 8 and the partially cutaway side view of FIG. 9. That is, the wire support part 7 has a wire 16 with silver brazing at the tip and is a thick connecting plate 7c that can withstand printing pressure.
and the armature 17 facing the magnetic pole core 4a of the electromagnet 4 are laser welded to the plurality of tongues 7d of the upper annular thin plate spring 7a in the relative positions as shown in the figure.A through hole is provided as an escape hole for the armature 17. A lower annular thin plate spring 7b having a weight of 7 g is fitted onto the outer periphery of the armature 17 to form a stacked spring system. Reference numeral 18 indicates a mounting hole for assembling the print head, and reference numeral 19 indicates a positioning hole.

On the other hand, the upper annular thin plate spring 7a has a plurality of tongues 7d radially extending from the outer peripheral edge 7f toward the center, as shown in the plan view of FIG. A cutout groove 7e is formed and manufactured by punching out a thin plate of spring steel or the like using a precision press.

The x mark indicates the position where the thick connecting plate 7c is set on the front side and the armature 17 is set on the back side, and the three members are simultaneously laser welded.

Further, FIG. 11 shows a plan view of the lower annular thin plate spring 7b, and the difference from the upper annular thin plate spring 7a in FIG. are similar.

A seventh device incorporating the wire support portion 7 explained above.
In the print head shown in the figure, when the electromagnet is not energized, a magnetic path is formed between the permanent magnet 3, the yoke 2, the auxiliary yoke 5, the armature 17, the air gap, and the magnetic pole iron core 4a. Therefore, the wire support part 7 is connected to the spring fulcrum 15
The armature 17 rotates counterclockwise around the center, and the armature 17 is attracted to the magnetic pole core 4a.

Next, when the electromagnet is excited, the magnetic flux of the electromagnet is induced in the opposite direction to the magnetic flux of the permanent magnet, the elastic force of the wire support part 7 overcomes the attractive force, and the wire support part 7 is centered around the spring fulcrum 15. Rotate clockwise. Therefore, the wire 16 moves in a straight line direction (in the direction of the solid line arrow) and presses the ink ribbon and recording paper (not shown) to perform printing.

[Problems to be solved by the invention] As explained above, the wire support part constituting the print head of a conventional dot printer consists of a plurality of annular thin plate springs (for example, upper and lower). The connecting plate was stacked on multiple tongues provided on the plate, and laser welding was performed so that the connecting plate and the armature sandwiched the annular thin plate spring. Furthermore, due to the repeated stress during printing, this welding point became fatigued, causing a defect that could lead to a breakage accident.

The present invention solves the above-mentioned deficiencies of the prior art, and reduces the bending stress applied to the welded part of the annular thin plate spring by arranging the stress part applied to the annular thin plate spring and the welded part apart from each other. purpose.

[Means for solving the problem] This invention consists of an armature that moves back and forth by energizing or de-energizing an electromagnet in response to a print signal, and an armature whose annular outer periphery is fixed to a yoke assembly of the head body and which moves toward the center. A thin plate spring made of an elastic body, which has a plurality of tongues extending radially, and a through hole in which the armature can be fitted loosely in the approximately middle portion of the tongue in the longitudinal direction; A connecting plate is welded Y, a printing wire is welded at right angles to the tip, and the armature is inserted in the through hole of the thin plate spring, and the connecting plate is placed in close parallel to and close to the thin plate spring, and the armature at the base end of the connecting plate and the armature at the tip end of the connecting plate. This invention proposes a print head for a wire dot printer, characterized in that the intermediate portion between the print head and the wire is welded to a thin plate spring.

[Example] An example of the present invention will be described below based on the drawings.

Fig. 1 is a partially cutaway side view of the printing head of a wire dot printer according to an embodiment of the invention, Figs. 2 and 3 are a plan view and a side view of the wire support section, and Fig. 4 is , FIG. 5 is a plan view of the upper annular thin plate spring to which the armature constituting the wire support portion is fixed, and FIG. 6 is a plan view of the lower annular thin plate spring.

Components that are the same as those in the conventional example shown in FIGS. 7 to 11 are designated by the same reference numerals.

FIG. 1 is an enlarged view of this embodiment corresponding to the wire support section 7 of FIG. 7. The configuration of the wire support section 20 will be explained with reference to FIGS. 2 to 6.

In Figure 4, there is a wire attachment hole 20i at the tip.
The armature 17 is welded at the base end (welded portion Y) to the thick connecting plate 20h that can withstand printing pressure.

In FIG. 5, a plurality of tongues 20c of the upper annular thin plate spring 20a extend radially from the outer peripheral edge 7f toward the center, and have a wire attachment hole 20d formed at the tip, and a wire attachment hole 20d is formed in the center of the tongue 20c. A through hole 20g, which is loosely fitted as a relief hole for the armature 17, opens. A Y-shaped notch groove 20 is provided between each tongue piece 20c.
e is formed and manufactured by punching out a thin plate of spring steel or the like using a precision press.

In FIG. 6, the lower annular thin plate spring 20b
differs from the above upper annular thin plate spring 20a in the following points:
The other aspects are the same except that the tongue piece 20c does not have a tip extending from the through hole 20g.

Next, to explain the assembly of each of the above parts, the wire attachment hole 20i of the connecting plate 20h and the wire attachment hole 20d of the upper annular thin plate spring 20a are overlapped, one end of the wire 16 is inserted, and the connecting plate 20h is welded by brazing. The upper annular thin plate spring 20a and the wire 16 are fixed (welded X) together.

Furthermore, the connecting plate 20h is laser welded (welding Z) to the opposing upper annular thin plate spring 20a at the intermediate portion between the base armature and the tip wire.
The armature 17 is loosely fitted into the through holes 20g of the upper and lower annular thin plate springs 20a and 20b, and both plate springs and connecting plates are welded in parallel.

Attach it to core group 1 by assembling as described above.
That is, the armature 17 is fitted onto the excitation coil 4b, the positioning holes are aligned, the fixing screw 13 is passed through the mounting hole 18, and the armature 17 is fixed with a hexagonal nut 14.

A backstop 9a is arranged on the cover 9 facing the base of the connecting plate 20h and separated from the connecting plate 20h. This is to prevent the connection plate 20h from overrunning upward as the armature 17 moves up and down. This gap is sized to provide some leeway in the armature stroke.

Next, the operation will be explained. When the electromagnet 4 is OFF, the armature 17 is attracted to the permanent magnet 3 and moves downward. At this time, the connecting plate 20h to which the armature 17 is fixed is connected to the wire 16.
and is pressed downward together with the upper and lower annular thin plate springs 20a and 20b. At this time, the leaf springs 20a and 20b into which the armature 17 is loosely fitted are not directly subjected to downward bending stress from the armature as in the conventional case, and the welding point Z is connected to the supported outer peripheral edge 7f.
Since it is far away from the center, the bending stress is smaller than that of the conventional case.

Next, when the electromagnet 4 is turned on, the armature 17 loses its downward pulling force, and the upper and lower annular thin plate springs 20a and 20
The connecting plate 20h to which the armature 17 is fixed also moves upward (to the printing position) together with the wire 16.
At this time, the bending stress applied to the welding point Z is also smaller than that of the conventional welding point because it is away from the outer peripheral edge 7f.

[Other Embodiments] In the above embodiments, the thin plate spring is made up of two sheets, but it may be made up of a larger number of sheets. In addition to welding point Z, there is also a wire attachment part (welding point
In , the connecting plate and the annular thin leaf spring were fixed, but
Instead of using the wire in common, both members may be fixed at one point.

Further, the print head using the wire support portion 20 according to the present invention is applicable not only to a 9-dot print head but also to a 24-dot print head.

[Effects of the invention] As described above based on the embodiments, according to the invention, the welding point Z between the connecting plate and the annular thin plate spring is located at a different position from the mounting part of the armature, so that the armature cannot be driven. As a result, no bending stress is applied to the welded part Z, and the conventional problems of fatigue and destruction are eliminated.

[Brief explanation of the drawing]

1 to 6 show one embodiment of the present invention, in which Fig. 1 is an enlarged partial sectional view showing the state in which the wire support part is assembled to the wire dot print head, Fig. 2 is a plan view of the wire support part, Fig. 3 is a sectional view of the same, Fig. 4 is a perspective view of the connecting plate, Fig. 5 is a plan view of the upper annular thin leaf spring, and Fig. 6 is a plan view of the lower annular thin leaf spring.
FIG. 1 shows a conventional example, FIG. 7 is a partial cross-sectional view of a wired printer head, FIG. 8 is a plan view of a wire support portion, FIG. 9 is a cross-sectional view of the same, FIG. 10 is a plan view of an upper annular thin leaf spring, and FIG. 11 is a plan view of a lower annular thin leaf spring. 3: permanent magnet, 4: electromagnet, 7, 20:
Wire support, X, Y, Z... welding points.

Claims (1)

[Scope of Utility Model Registration Claim] An armature that moves back and forth by energizing or de-energizing an electromagnet in response to a print signal, and a plurality of armatures whose annular outer periphery is fixed to a yoke assembly of the head body and which extend radially toward the center. A thin plate spring made of an elastic body, which has a tongue piece formed therein, and a through hole in which the armature can be fitted loosely is provided at approximately the middle part in the longitudinal direction of the tongue piece; the armature is welded to the base end, and the tip part The printing wire is welded at a right angle to the connecting plate, and the armature is inserted into the through hole of the thin plate spring, and the connecting plate is placed parallel to and close to the thin plate spring, and the intermediate part between the armature at the base end and the wire at the tip of the connecting plate A print head for a wire dot printer characterized by a welded Z to a thin plate spring.