JPS6134133Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a print wheel mounting device for a printer.

Conventionally, in a serial printer using a print wheel with a large number of type parts on the outer periphery,
The print wheel must be selected and replaced depending on the type of type. For this purpose, as shown in FIG.
is formed, the hub 3 is pushed into this fitting part 5, and the rotation locking part 6 of the rotary plate 2 is attached to the print wheel 4.
The motor 1 and the print wheel 4 are connected by engaging with the hub 3. However, if there is any play between the fitting part 5 and the hub 3, the rotation transmission will be inaccurate, so it is necessary to push the motor 1 and the print wheel 4 together without causing any play. Must-have. Therefore, a large force is required for fitting, and there is a risk that the print wheel may be tilted with respect to a plane perpendicular to the axis of the hub 3.

This invention has been developed in view of these points, and the object is to provide a print wheel mounting device for a printer that facilitates the mounting and removal of the print wheel and also ensures that the print wheel is securely mounted.

This idea provides a centering section made of a magnetic material on the print wheel, and a permanent magnet that approaches and leaves the front surface of the centering section using a knob, and the rotating body made of a magnetic material connected to the motor and the centering section are coaxially connected to each other. The magnetic coupling force of the centering part is changed by the movement of the permanent magnet toward and away from the centering part, and therefore,
The rotating body and the print wheel are magnetically attached very easily, and the centering part is centered and fitted to the rotating body, and the rotation locking part is engaged to connect the rotating body and the print wheel. It is constructed so that it can be connected reliably.

An embodiment of this invention will be explained based on FIGS. 2 to 8. The same parts as those explained in FIG. 1 will be explained using the same reference numerals. 1 is a motor, and a plate-shaped rotating body 2 made of a magnetic material is connected to the motor 1. This rotary body 2 is provided with a detent locking portion 6 bent in the axial direction and a conical protrusion 7 projecting on the axis at the outer circumferential portion. The print wheel 4 has a plurality of radially projecting pieces 8.
A type portion 9 is formed at the tip of each of these pieces 8, and a rotation locking portion 10 that engages with the rotation locking portion 6 is formed. Furthermore, a recess 11 is formed in the center of the print wheel 4 and projects forward on the opposite side from the motor 1. A centering disk 12, which is a centering portion made of a magnetic material, is fitted into the recess 11 while being prevented from rotating by a rotation preventing projection 13 protruding from its outer periphery.
A conical hole 14 is formed in the center of the centering disk 12 and is fitted into the conical projection 7 in a tapered manner. Further, a permanent magnet 15 is fitted into the recess 11 so as to be prevented from rotating and slidable in the axial direction.
A guide cylinder 16 is fixedly fitted into the center of this permanent magnet 15. This guide tube 16 is formed with a protrusion 18 that engages with a recess 17 formed in the permanent magnet 15 and is prevented from rotating, and a protrusion 19 that protrudes from the inner circumferential surface. Furthermore, the recess 11
A knob 20 is rotatably fitted into the holder, and a helical lead screw 21 and a slot 22 are formed on the shaft portion of the knob 20 to engage with the projection 19. The knob 20 is urged by a plate spring 23 fixedly inserted into the slot 22 so that the flange portion 24 comes into close contact with the front end of the recess 11. The plate spring 23 includes a U-shaped fitting portion 27 that is inserted into the slot 22 and has a hole 26 that is inserted into the protrusion 25 formed in the slot 22;
Elastic pieces 29 and 30 having protruding portions 28 facing each other with an interval of 180° are formed. At the bottom of the recess 11, four locking holes 31 are formed at 90° intervals to engage with the protrusion 28.

In such a configuration, at the position of the knob 20 shown in FIG. 1, the distance between the centering disk 12 and the permanent magnet 15 is large, and the magnetic coupling force between the centering disk 12 and the rotating body 2 is weak. . Therefore, the force required to remove the print wheel 4 is extremely small. When attaching the print wheel 4, the rotating body 2 and the centering disk 12 are faced to each other with this magnetic coupling force being weak, and a centering operation is performed in which the conical protrusion 7 is fitted into the conical hole 14. is also easy. Next, knob 2
When turning 0 by 90 degrees, the protrusion 19 connects to the lead screw 21.
By engaging with the guide tube 16 and the permanent magnet 15, the guide tube 16 and the permanent magnet 15 approach the centering disk 12, increasing the magnetic coupling force between the rotating body 2 and the centering disk 12. Therefore, the force required to attach and detach the print wheel 4 can be extremely small, and the print wheel 4 can be attached at right angles to the axis of the rotating body 2. Note that when rotating the knob 20, clear moderation can be obtained by the engagement between the protrusion 28 of the leaf spring 23 and the locking hole 31 of the recess 11.

Since this invention is constructed as described above, the centering part of the print wheel and the rotating body can be very easily connected by the magnetic coupling force of the permanent magnet, and the centering part of the print wheel and the rotating body can be connected very easily. This has the advantage that the unloading operation can be carried out extremely easily in a state where the magnetic coupling force is weak.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional side view showing an example of the conventional method, Figs. 2 to 8 show an embodiment of this invention, and Figs. 2 and 3 show the approach and separation of the permanent magnet from the centering disk. 4 is a front view and a cross-sectional view of the centering disk, FIG. 5 is a side view and a front view of the permanent magnet, FIG. 6 is a front view and a cross-sectional view of the guide tube, and FIG. 7 is a longitudinal side view showing the operation. The figure shows a top view, side view, and front view of the knob.
FIG. 8 is a side view and a front view of the leaf spring. DESCRIPTION OF SYMBOLS 1... Motor, 2... Rotating body, 4... Print wheel, 6... Rotation locking part, 9... Type part, 10... Rotation locking part, 12... Centering disc (center ), 15...Permanent magnet, 20...Knob.

Claims (1)

[Scope of utility model registration request] A rotating body connected to a motor is formed of a magnetic material, a print wheel is provided having a plurality of printed parts on the outer periphery and facing the front surface of the rotating body, and the print wheel is fitted coaxially to the rotating body. A centering part made of a magnetic material to be aligned is provided, and a permanent magnet is provided that moves toward and away from the front surface of the centering part by a knob, and the permanent magnets are engaged with opposing surfaces of the print wheel or the centering part and the rotating body. A print wheel mounting device for a printer, characterized in that a rotation prevention locking portion is formed.