JPH0647725Y2 - Wire dot head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a wire dot head.

[Conventional technology]

A description will be given based on FIGS. 2 and 3. FIG. 2 is a structural example of a wire dot head, and FIG. 3 is a perspective view of a metal damper spacer portion. In FIG. 2, the armature 10 is attracted by the energization of the coil 5, and the wire 6 arranged at the tip of the armature causes the printing paper 9 through the ribbon 7.
Are struck on the platen 8 to form dots on the printing paper 9. The armature 10 is returned to the standby position by the repulsive force due to the collision with the printing paper and the spring force of the wire return spring 4. An elastic body 33 is installed on the side opposite to the platen in order to absorb the impact force of the armature 10 when it is returned and quickly return the armature 10 to a predetermined waiting position. Elastic body
On the 33, a metal damper spacer 31 is attached in order to prevent the armature 10 from cutting into the elastic body 33 and breaking the elastic body 33 by cutting. The metal damper spacer 31 is extremely thin, about 0.05 mm, so as not to reduce the impact absorption capability of the elastic body 33, and the armature 10
High hardness steel is used so that it will not be destroyed even if it collides with. The elastic body 33 and the metal damper spacer 31 are held by a holding member 32. As shown in FIG. 3, since the metal damper spacer 31 has a specified shape 31-b of the collision portion with the armature 10, the holding member 2 that determines the mounting position of the metal damper spacer 31 and the armature 10 has a shape. Positioning engagement portions 31-a and 32-a are provided that are engaged with each other and perform positioning. The metal damper spacer 31 is manufactured by pressing or etching.

[Problems to be solved by the device]

However, in the above-mentioned structure, the vibration of the metal damper spacer due to the impact at the time of armature collision causes the metal damper spacer to bite into the convex portion of the positioning engagement of the holding member during long-term use, and the metal damper spacer at that portion The rigidity of the armature increases, normal shock absorption cannot be performed, the armature may not operate properly, or the metal damper spacer may be damaged in some cases, and the fragments may scatter inside the head drive, damaging the drive part. It was sometimes lost. In order to prevent this bite, it is sufficient to increase the thickness of the metal damper spacer and increase the contact area, but the rigidity of the metal damper spacer becomes high, and it becomes impossible to obtain the prescribed shock absorption capability. There was a problem of being lost. As means for preventing the metal damper spacer from biting while maintaining the shock absorbing ability, (1) a pin having a high hardness is driven into a positioning engagement portion of the holding member with the metal damper spacer, and (2) a holding member. There have been means such as subjecting the entire surface to high hardness surface treatment (plating, carburizing, etc.), (3) using a material having a high hardness as the material of the holding member itself.

However, these methods have a problem that the shape of the holding member is limited (a complicated shape cannot be formed) and the cost is increased.

Therefore, the present invention solves such a problem, and an object of the present invention is not to limit the material of the holding member so much while maintaining the shock absorbing ability, and it can withstand long-term use at low cost. To provide a wire dot head.

[Means for Solving the Problems]

The wire dot head according to the present invention is provided with an armature for driving a wire provided at a tip thereof, an elastic body for damping movement of the armature at the time of returning, and a plurality of positioning protrusions abutting on the back surface of the elastic body. A holding member for holding the body, and a thin plate-shaped metal damper spacer provided on the surface of the elastic body and provided with a plurality of positioning engaging portions that are bent so as to slidably contact the side surface of the positioning protrusion. It is what

[Action]

As described above, if the metal damper spacer is used, the contact area of the positioning engagement portion with the holding member can be set to be large depending on the material of the holding member while maintaining the elasticity required for shock absorption of the armature. Therefore, the metal damper spacer does not bite into the positioning engagement portion of the holding member and can withstand long-term use.

[Embodiment 1] An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, press working is performed so that the contact portion width l of the positioning engagement portion 1-a with the holding member 2 of the metal damper spacer 1 is 2-3 times the thickness of the metal damper spacer plate (0.05 mm). It is bent at. The material of the metal damper spacer is SUS304 4 steel, which can be easily bent and has high hardness.

BS is used as the holding member. As a result of carrying out the life test of the wire dot head with this combination, stable head performance can be obtained without the metal damper spacer biting into the positioning engaging portion 2-a of the holding member even at 2 oc strokes / wire. I was able to.

[Example 2] In the metal damper spacer, a metal damper spacer bent so that the positioning engagement portion width l of the metal damper spacer has a dimension of 5 to 6 times the metal damper spacer plate thickness (0.05 mm); In the combination with the holding member, a 2-octoke / wire life test was performed, and as a result, the metal damper spacer did not bite into the positioning engagement portion 2-a of the holding member, and good results were obtained. .

Table 1 shows the results of the examples and the prior art.

Meaning of symbols in the table ×: 0.5 oct stroke / bite before wire occurs △: 1 oct stroke / wire to 1.5 oct stroke / bite occurs with wire ○: 2 oct stroke / no bite occurs at the wire EFFECTS OF THE INVENTION According to the present invention, the positioning engagement portion of the metal damper spacer has a simple shape such as a bent shape, so that the material of the holding member, surface treatment, etc. are not limited and can be maintained for a long period of time. The effect is to obtain stable head performance. Further, since it is not necessary to require a special material or surface treatment for the holding member, the cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a metal damper spacer portion showing an embodiment of the present invention. FIG. 2 is a sectional view showing a structure of a wire dot head. FIG. 3 is a perspective view showing an example of a conventional metal damper spacer portion. 1-Metal damper spacer 1-a-Positioning engagement part of metal damper spacer 2-Holding member 2-a-Positioning engagement part of holding member 3--Elastic body 4--Wire return spring 6 --- wire

Claims (1)

[Scope of utility model registration request] 1. An armature for driving a wire provided at a tip, an elastic body for damping movement of the armature at the time of return, and a plurality of positioning protrusions abutting on the back surface of the elastic body, the elastic body And a thin plate-shaped metal damper spacer provided on the surface of the elastic body and provided with a plurality of positioning engaging portions that are bent so as to be in sliding contact with the side surface of the positioning protrusion. Characteristic wire dot head.