JPH0547651Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial field of application] The present invention relates to a type wheel selection mechanism, and in particular to a type wheel in a printer that selects appropriate type based on the contents of a printing command and stops the type wheel at the printing position. Concerning the selection mechanism.

[Conventional technology]

In conventional type wheels and printers equipped with a type wheel selection mechanism, the type wheels, on which letters, numbers, symbols, etc. are formed on the outer periphery, are arranged in parallel in the axial direction for the same number of digits required for printing. A selection claw of a type wheel selection mechanism provided corresponding to each type wheel is driven to select each type wheel.

Further, the conventional type wheel selection mechanism is provided with the same number of electromagnetic means as the type wheels, and by energizing the electromagnetic means, the selection pawl is driven in the selection direction, and the selection pawl is placed in the locking recess that stops the type wheel. When engaged, the type is stopped at the printing position.

In such a conventional type wheel selection mechanism,
Since the same number of electromagnetic means as selection claws are provided, the structure is complex, the number of parts is large, the overall shape of the printer is large, and the coils of each electromagnetic means must be energized, resulting in high power consumption. It was hot.

Therefore, the present inventor has proposed a type wheel selection mechanism in which each of the two type wheels can be appropriately selected by driving two selection pawls separately using one electromagnetic clutch.

FIGS. 2 to 4 show such a type selection mechanism, in which an electromagnetic clutch 2 is connected to a selection shaft 1 extending in a parallel direction of the type wheel units. The electromagnetic clutch 2 is composed of an electromagnetic coil 4 in which a rotating sleeve 3 made of a magnetic material is rotatably loosely fitted into a center hole, and a support member 5 that supports the electromagnetic coil 4. has been done. Further, the rotary sleeve 3 is connected to the selection shaft 1 by a spline connection (not shown), so that the rotation sleeve 3 is always driven to rotate integrally with the selection shaft 1.

Further, a pair of plates 6 made of magnetic material are provided at both axial ends of the electromagnetic clutch 2, respectively.
6 is loosely fitted onto the selection shaft 1, and each of these pair of plates 6, 6 has a leaf spring member 7 interposed between it and another pair of adjacent plates (not shown). The end face of the rotary sleeve 3 and the inner surface of the plate 6 are brought into elastic contact with each other by the spreading elasticity. The pair of plates 6, 6 are formed in a symmetrical shape, and each of the plates 6 has a type ring extending from a central disk portion that comes into elastic contact with the end surface of the rotary sleeve 3 and covers the end surface of the electromagnetic coil 4. a selection pawl 8 that engages and disengages from a locking recess (both not shown) to selectively stop the type wheel, and a locking pawl 11 that engages and disengages from a peak 10a of a locking spring 10 fixed to the case 9; The engagement between the magnetic field closing tongue part 14 which holds the drive plate 13 made of a magnetic material to which the drive shaft 12 is fixed and the selection claw 8 which is engaged with the locking recess part is released when resetting the type. A scooping protrusion 15 used for scooping is provided in a protruding manner.

In the type wheel selection mechanism, when the electromagnetic coil 4 is not energized, the pair of plates 6, 6 are affected by the frictional force between the end surface of the rotary sleeve 3 and the inner surface of the plate 6 and the magnetic field closing tongue portion 14. The locking pawl 11 of the plate 6 is held at the initial position held below the peak 10a of the locking spring 10 against the frictional force between the micro protrusion 16 formed on the drive plate 13. .

When the electromagnetic coil 4 is energized, the pair of plates 6, 6 are attracted to the rotating sleeve 3 by magnetic force, and the electric field closing tongue portion 14 of the plate 6 is attracted to the rotary sleeve 3 by magnetic force.
The drive plate 13 fixed to the drive shaft 12 is held between the two. Thereby, rotational force is transmitted to the plate 6 by the rotational drive of the rotary sleeve 3 by the selection shaft 1 and the rotational drive of the drive plate 13 by the drive shaft 12, and the locking pawl 11 of the plate 6 is rotated by the locking spring. It is rotated so as to overcome the peak portion 10a of No. 10. The selection pawl 8 of the plate 6 is used to stop the type wheel at a desired position to perform desired printing.

When resetting the type ring, a reset cam (not shown) rotates the scooping protrusion 15 of the plate 6 clockwise in FIG. The plate 6 is returned to its initial position by being moved over downwardly.

[The problem that the idea attempts to solve]

However, in the type wheel selection mechanism shown in FIGS. 2 to 4, the rotary sleeve 3 is made of iron material, and the surface of the rotary sleeve 3 is in contact with the inner circumferential surface of the electromagnetic coil 4. In order to reduce the frictional force, a lubricant such as oil is applied, so when the electromagnetic coil 4 is energized to attract the plate 6, this lubricant film acts as a resistance.
The plate 6 cannot be quickly suctioned,
There is a problem in that the response speed of the attraction operation to the energization of the electromagnetic coil 4 is reduced. Moreover, in order to prevent such a reduction in reaction speed, the drive plate 13 is sandwiched to obtain rotational force, so the drive plate 13 is required, which complicates the structure and increases manufacturing costs. There is a problem.

The present invention has been made in view of these points, and the object is to provide a type wheel selection mechanism that can increase the reaction speed of the suction operation of the plate to energization of the electromagnetic coil without using a drive plate. That is.

[Means to solve the problem]

In order to achieve the above object, the type wheel selection mechanism according to the present invention is provided with an electromagnetic clutch for every two digits of the type wheel, each consisting of a rotary sleeve that is loosely fitted into the center hole of an electromagnetic coil, and which is rotated at all times. Plates each having a selection pawl formed thereon for stopping the type wheel at a desired type position are disposed at both axial ends of the plate, and each plate is attracted to the rotary sleeve by energization of the electromagnetic coil to be integrated into one piece. The type wheel selection mechanism rotates and stops the type wheel using the selection pawl, characterized in that the rotating sleeve is made of a sintered material.

[Effect]

According to the type wheel selection mechanism of the present invention, since the rotary sleeve is formed of a sintered material, pores are formed in the rotary sleeve, and a lubricant such as oil is applied to the outer periphery of the rotary sleeve. When applied, the lubricant penetrates into the interior of the pores, so that no excess lubricant is present on the outer periphery of the rotating sleeve. Therefore, when the electromagnetic coil is energized, the lubricant does not act as resistance and prevent the suction operation of the plate, and the reaction speed of the plate can be significantly increased. Since a drive plate is not required for transmitting rotational force, the structure is simple and can be easily manufactured, and manufacturing costs can be reduced.

〔Example〕

Hereinafter, an embodiment of the present invention will be described with reference to FIG.
The same parts as those in FIG. 4 will be described with the same reference numerals.

FIG. 1 shows an embodiment of the present invention, in which a rotating sleeve 3a made of a sintered magnetic material is loosely fitted into the center hole of an electromagnetic coil 4 and is spline-coupled to the selection shaft. The rotating sleeve 3a and the electromagnetic coil 4 constitute an electromagnetic clutch 2.

Further, a pair of plates 6 made of magnetic material are provided at both axial ends of the electromagnetic clutch 2, respectively.
6 is loosely fitted to the selection shaft 1, and the pair of plates 6, 6 elastically press the end surface of the rotary sleeve 3 and the inner surface of the plate 6 by the spreading elasticity of a leaf spring member (not shown). It is designed so that they are in contact with each other. The pair of plates 6, 6 are formed symmetrically, and a part of the plate 6 (lower in FIG. 1) has a magnetic flux of a closed magnetic field formed when the electromagnetic coil 4 is energized. In order to maintain a high density, the magnetic field closing tongues 14 without microprotrusions 16 are arranged close enough to each other to avoid contact.

Next, the operation of this embodiment will be explained.

In this embodiment, when the electromagnetic coil 4 is energized, the pair of plates 6, 6 are moved to the rotating sleeve 3.
The rotational force of the selection shaft 1 drives the plate 6 to rotate together with the rotary sleeve 3, thereby selecting a desired type on a type wheel (not shown). When the electromagnetic coil 4 is de-energized, the plate 6 is separated from the rotating sleeve 3 and returned to its initial position by a reset mechanism (not shown).

At this time, in this embodiment, since the rotating sleeve 3 is made of a sintered material, pores are formed in the rotating sleeve 3.
When a lubricant such as oil is applied to the outer periphery of the rotary sleeve 3, the lubricant penetrates into the pores, thereby eliminating the presence of excess lubricant on the outer periphery of the rotary sleeve 3. .

Therefore, in this embodiment, when the electromagnetic coil 4 is energized, the lubricant does not act as resistance and prevent the suction operation of the plate 6, and the reaction speed of the plate 6 can be significantly increased. becomes possible. Moreover, as described above, since the reaction speed of the plate 6 when the electromagnetic coil 4 is energized can be increased, the drive plate 13 for transmitting rotational force to the plate 6 and the drive shaft 12 for rotating it, etc. is not required, the structure is simple, it can be easily manufactured, and manufacturing costs can be reduced.

Note that the present invention is not limited to the above-mentioned embodiments, and can be modified as necessary.

[Effect of idea]

As described above, in the type wheel selection mechanism according to the present invention, the rotary sleeve is formed of a sintered material and the lubricant is infiltrated into the pores formed in the rotary sleeve. There is no excess lubricant on the outer periphery of the electromagnetic coil, and when the electromagnetic coil is energized, the lubricant does not act as resistance and impede the suction operation of the plate, making it possible to significantly increase the reaction speed of the plate. becomes. Moreover, as mentioned above, the reaction speed of the plate when the electromagnetic coil is energized can be increased, so there is no need for a drive plate to transmit rotational force to the plate, resulting in a simple structure and easy manufacturing. This has the advantage of being able to reduce manufacturing costs.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the type wheel selection mechanism of the present invention, FIG. 2 is a side view showing a conventional type wheel selection mechanism, and FIG. 3 is an exploded perspective view of a part of the conventional example. FIG. 4 is a longitudinal sectional view of a conventional example. 2... Electromagnetic clutch, 3... Rotating sleeve, 4
...Electromagnetic coil, 6...plate.

Claims (1)

[Scope of utility model registration request] An electromagnetic clutch consisting of a rotating sleeve that is always driven to rotate loosely fitted into the center hole of an electromagnetic coil is provided for every two digits of the type ring, and the type ring is stopped at a desired type position at both axial ends of this electromagnetic clutch. a type wheel, in which plates each having a selection pawl formed thereon are disposed, and when the electromagnetic coil is energized, the plates are attracted to the rotary sleeve and rotated together, and the selection pawl stops the type wheel; A type wheel selection mechanism, wherein the rotary sleeve is made of a sintered material.