JPH0743482Y2 - Eccentric bush fixing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an eccentric bush fixing device used when adjusting the position of the center of a shaft.

Prior Art First, a conventional example is shown in FIGS. Although only one side is shown, 1 is a support body such as a frame, and the eccentric bush 2 is held by these support bodies 1. These eccentric bushes 2 are shafts of a bearing portion 6 in which both ends of a shaft 5 are fitted to the shaft center of a cylindrical portion 4 rotatably fitted in a fitting portion 3 formed in the support 1. The center is eccentric, and a large number of teeth 7 are integrally formed on the outer periphery of the cylindrical portion 4 at equal intervals. Further, a tightening ring 8 that is in contact with the end surface of the eccentric bush 2 is locked at the end of the shaft 5.
Further, as shown in FIGS. 7 and 8, the eccentric bush 2
A mark 9 is formed on each of the teeth 9 in the vicinity of the tooth 7.

Therefore, the eccentric bush 2 can be rotated around the shaft center of the cylindrical portion 4, and the position of the shaft center of the bearing portion 6 is changed according to this rotation angle to adjust the position of the shaft center of the shaft 5. be able to. In this case, the guideline for the rotation angle of the eccentric bush 2 can be judged by looking at the position of the mark 9, and the eccentric bush 2 can be turned to an arbitrary position as shown in FIG. 7 or 8. After this adjustment work, the eccentric bush 2 is fixed by the locking body 30. The locking body 30 is rotatably held by the support body 1 around a fulcrum 10, a pawl 31 meshed with the teeth 7 of the eccentric bush 2 is formed at one end, and the fulcrum 10 is formed at the other end. An elongated hole 11 is formed along the centered radius. Therefore, by engaging the tooth 7 and the claw 31 with each other and tightening the screw 12 passed through the long hole 11 to the support body 1,
30 is fixed, and the eccentric bush 2 is fixed by this locking body 30.

Problems to be Solved by the Invention There are various reasons for determining the position of the shaft center of the shaft 5. For example, in a line printer, if the shaft center of the shaft of the print drum is not constant, the relative position between the print drum and the print hammer changes, and a phenomenon of one-sided contact occurs during printing. Further, in a dot printer or the like, a clear printing state cannot be obtained unless the gap between the tip of the dot printer head held by a carrier that moves along the platen and the printer is constant. Therefore, the eccentric bushes that support the shafts at both ends of the carrier shaft or both ends of the platen are rotated to determine the positions of the shaft centers of those shafts.

Thus, fine adjustment may be required to determine the position of the shaft 5. This requirement is achieved by making the pitch of the teeth 7 of the eccentric bush 2 fine, but on the other hand, since the teeth 7 are small, the amount of meshing with the pawl 31 of the locking body 30 is insufficient, and the eccentric bush 2 is fixed. If the pitch of the teeth 7 is increased in order to obtain a sufficient fixed state, the adjustment accuracy of the position of the shaft 5 is deteriorated.

Means for Solving the Problems The shaft center of a bearing part in which both ends of the shaft are fitted is eccentric to the shaft center of a cylindrical part that is rotatably fitted in a fitting part formed in a support body. A pair of eccentric bushes, a large number of teeth arranged at equal intervals on the outer peripheral portions of these eccentric bushes, a claw that meshes with the valleys of these teeth, and a tooth located at the center of the tip of this claw that meshes with the teeth. And a locking body that has a groove formed in a shape and that is movable forward and backward with respect to the outer circumference of the eccentric bush.

Action Selecting a state in which the pawl of the locking body is engaged with the root of the tooth of the eccentric bush and a state in which the groove formed at the center of the tip of the pawl is engaged with the tip of the tooth of the eccentric bush. Thus, the rotation angle of the eccentric bush can be finely adjusted with a pitch of ½ of the tooth pitch of the eccentric bush.

Embodiment An embodiment of the present invention will be described with reference to FIG. 1 and FIG. The same parts as those described in FIGS. 6 to 8 are designated by the same reference numerals, and the description thereof will be omitted. As shown in FIGS. 1 to 3, the support 1 is provided with a locking body 13 which rotates about a fulcrum 10. At one end of these locking bodies 13, a claw 14 that substantially matches the shape of the valley of the tooth 7 of the eccentric bush 2 and a V-shaped groove 15 formed at the center of the tip of the claw 14 are formed. A slot 11 is formed at the other end. The print drum 16 in the line printer has a shaft 5 protruding from both ends, and both ends of the shaft 5 are rotatably supported by the bearing portion 6 of the eccentric bush 2.

Next, as shown in FIGS. 4 and 5, a comb-teeth-shaped paper stopper 18 for supporting the paper 17 is provided on the outer periphery of the print drum 16. An ink roller 19 supplies ink to the print drum 16. Further, the print hammers 20 facing each other on the outer periphery of the print drum 16 are urged in the returning direction by the springs 21 and are rotatably held around the shaft 22, and are engaged with the print hammers 20. A trigger (23) is urged upward by a spring (24) and held by a guide member (25) so as to be vertically movable and horizontally movable. Further, a plurality of electromagnets 26 are arrayed, and a pin 28 connected to the rotating free end of the armature 27 of these electromagnets 26 is arranged in the vicinity of the upper surface of the trigger 23. Further, one power shaft 29 having a ridge 29a on the outer circumference is connected to the motor and provided along the arrangement direction of all the trigger shafts 23.

In such a structure, the trigger 23 is normally pulled upward by the urging force of the spring 24 as shown in FIG. 4, but when a specific electromagnet 26 is excited, as shown in FIG. Since 27 is attracted to the core of the electromagnet 26, the pin 28 pushes down the trigger 23 so as to interfere with the rotation locus of the protrusion 20a of the power shaft 29. As a result, the trigger 23 is kicked by the ridge 29a of the power shaft 29, and the print hammer 20 collides with the print drum 16 with the paper 17 in between. As a result, printing is performed.

Here, the shape of the tip of the print hammer 20 is formed in an arc shape so as to match the outer peripheral surface of the print drum 16.
If the position of the shaft center of the
Hits the print drum 16 one-sided. For this purpose, as shown in FIG. 3, the screw 12 is loosened to retract the locking body 13 from the outer circumference of the eccentric bush 2, and in this state, the eccentric bush 2 is rotated to adjust the position of the shaft center of the shaft 5. At this time, as shown in FIG. 1, the state in which the claws 14 of the locking body 13 are engaged with the valleys of the teeth 7 of the eccentric bush 2 and the central part of the tip of the claws 14 as shown in FIG. By selecting a state in which the groove 15 formed on the eccentric bush 2 is engaged with the tooth tips of the teeth 7 of the eccentric bush 2, the rotation of the eccentric bush 2 is performed with a half pitch of the pitch of the teeth 7 of the eccentric bush 2. You can fine-tune the corners. Also,
Since it is not necessary to make the pitch of the teeth 7 smaller than necessary,
The claw 14 or the groove 15 and the tooth 7 are meshed with each other with a sufficient meshing amount, so that the eccentric bush 2 can be reliably prevented from rotating. Furthermore, the existing eccentric bush 2 can be used by replacing the locking body 13 having the groove 15 at the tip of the pawl 14, and therefore the cost required for improving the fixing device for the eccentric bush 2 can be reduced. .

Effect of the Invention As described above, the present invention has a shaft center of a bearing part in which both ends of the shaft are fitted to a shaft center of a cylindrical part rotatably fitted in a fitting part formed in a support body. A pair of eccentric bushes that are eccentric, a large number of teeth arranged at equal intervals on the outer periphery of these eccentric bushes, a claw that meshes with the troughs of these teeth, and a center of the tip of this claw. By having a locking body that has a groove formed in a shape that meshes with the teeth and that is provided so as to be movable back and forth with respect to the outer circumference of the eccentric bush, the claws of the locking body are provided with teeth of the eccentric bush. It is possible to select a state of engaging the valley portion and a state of engaging the groove formed in the central portion of the tip of the claw with the tooth tips of the teeth of the eccentric bush, whereby the pitch of the teeth of the eccentric bush is selected. The rotation angle of the eccentric bush can be finely adjusted with a half pitch of Since it is not necessary to reduce the tooth pitch of the eccentric bush more than necessary, the claw or groove and the tooth can be engaged with each other with a sufficient amount of engagement, and the eccentric bush can be reliably prevented from rotating. The existing eccentric bush can be used by replacing the locking body having the groove with the above, and therefore, the cost required for improving the fixing device for the eccentric bush can be reduced.

[Brief description of drawings]

1 to 5 show an embodiment of the present invention.
1 and 2 are side views showing a state in which the eccentric bush is fixed, FIG. 3 is a side view showing a state in which the locking body is retracted from the eccentric bush, and FIG. 4 is a partially sectioned line. FIG. 5 is a side view of the printer, FIG. 5 is a side view showing the printing operation,
6 to 8 show a conventional example, FIG. 6 is a sectional view showing a support structure for an eccentric bush and a shaft, and FIGS. 7 and 8 are side views showing a state where the eccentric bush is fixed. is there. DESCRIPTION OF SYMBOLS 1 ... Support body, 2 ... Eccentric bush, 3 ... Fitting part, 4 ... Cylindrical part, 5 ... Shaft, 6 ... Bearing part, 7 ... Tooth, 13 ... Locking body, 14 ...
Nail, 15 ... groove

Claims (1)

[Scope of utility model registration request] 1. A pair of bearings, in which both ends of a shaft are fitted with respect to an axis of a cylindrical part which is rotatably fitted into a fitting part formed on a support body, and a shaft center of which is eccentric. Eccentric bush, a large number of teeth arranged at equal intervals on the outer periphery of these eccentric bushes, a claw that meshes with the valleys of these teeth, and a shape that is located at the center of the tip of this claw and meshes with the teeth. An eccentric bush fixing device, comprising: a locking body having a groove formed therein and being capable of advancing and retracting with respect to the outer circumference of the eccentric bush.