JPH043145Y2 - - Google Patents

Description

[Detailed description of the invention] [Summary] A pair of half-shaft bearings are provided in the shaft bearings in which the lever holds the first and second planetary gears, and the first and second planetary gears are held in the half-shaft bearings. The structure of the planetary gear mechanism is simplified by compressing the rotating shafts of the gears.

[Industrial application field]

The present invention relates to a planetary gear mechanism used, for example, to wind up an ink ribbon in a fixed direction in a printer or the like.

Recently, various serial printers have been used as input/output terminals of data processing devices, word processors, and the like.

Among them, serial dot printers print characters etc. made up of dots, so there are many types of characters etc., and office automation (OA:
Its use as a terminal device in office automation is increasing.

Most of these printers use an ink ribbon, and when printing, the ink ribbon is wound up in a fixed direction.

A planetary gear mechanism is used in this winding part, but in order to lower the price, there is a need to reduce the number of parts and simplify assembly.

[Conventional technology]

As shown in the schematic diagram of FIG. 2, a printer to which a conventional planetary gear mechanism is applied has a platen 1, a print head 2 facing the platen 1, and a print head 2.
and a carrier 3 which is mounted with an ink ribbon cassette (not shown) mounted on the carrier 3 and moves back and forth parallel to the platen 1 as shown by arrow C-D. Printing is performed on paper 4 on platen 1 via an ink ribbon supplied to the front surface of paper 4 .

During printing, it is necessary to always wind up the ink ribbon in a fixed direction, and for this purpose, the carrier 3 is equipped with an ink ribbon winding mechanism.

For example, a planetary gear mechanism 5 as shown in the drawing is used as the ribbon winding mechanism.

The planetary gear mechanism 5 includes a drive shaft 6 that engages with a winding mechanism (not shown) of the ink ribbon cassette to rotate the winding mechanism, a drive shaft gear 7 attached to the drive shaft 6, and a drive shaft gear 7. A first planet gear 8 facing the drive shaft gear 7, an idle gear 9 meshing with the drive shaft gear 7, a second planet gear 10 facing the idle gear 9, and meshing with the first and second planet gears 8, 10. a lever 13 that brakes and supports the rotation of the first and second planetary gears 8 and 10 and rotatably engages the shaft portion 12 of the sun gear 11; It consists of a rotating means 14 for rotating.

The rotating means 14 includes a pulley 15 fixed to the shaft 12 of the sun gear 11 and a rope 16 wound around the pulley 15 and stretched parallel to the platen 1.

Therefore, when the carrier 3 moves in either the left or right direction by a drive source (not shown), the rope 16
It is pulled clockwise or counterclockwise.

The operation of the planetary gear will be explained below with reference to the operation diagram shown in FIG.

When the carrier moves to the right (in the direction of arrow D) in the state shown in FIG. 3a, the pulley 15 rotates counterclockwise (in the direction of arrow E) and rotates the sun gear 11 in the same direction.

Then, the first planetary gear 8 and the second planetary gear 10 that are meshed with the sun gear 11 both rotate clockwise, and the drive shaft gear 7 that is meshed with the first planetary gear 8 is rotated counterclockwise. At the same time, the drive shaft 6 is rotated in the same direction (counterclockwise) to wind up, for example, an ink ribbon (not shown).

At this time, the first planetary gear 8 is pressed against the drive shaft gear 7 by the rotational force of the sun gear 11, so that the first planetary gear 8 does not come out of mesh.

Next, when the carrier moves to the left (in the direction of arrow C), the pulley 15 rotates clockwise (in the direction of arrow F), as shown in FIG.

Then, the first planetary gear 8 and the second planetary gear 10 that are meshed with the sun gear 11 both rotate counterclockwise, and the lever 13 is rotated counterclockwise due to the rotational force of the sun gear 11. The second planetary gear 10 is engaged with the idle gear 9, and the drive shaft gear 7 is rotated counterclockwise via the idle gear 9, and at the same time, the drive shaft 6 is rotated in the same direction (counterclockwise). Wind up the ink ribbon.

That is, the drive shaft 6 is configured to always rotate counterclockwise to wind up the ink ribbon even if the carrier moves in either the left or right direction.

Furthermore, when the planetary gears 8 and 10 are alternately switched as the lever 13 rotates, if the engagement of the supporting portion of the lever 13 that supports the planetary gear is loose, the rotational force of the lever 13 will be insufficient. , the phenomenon of tooth skipping occurs when teeth mesh smoothly.

In order to avoid this phenomenon of tooth skipping, braking force is added to the rotation of the planetary gear.

As the method of adding, for example, the method shown in the enlarged side view of the holding portion in FIG. 4 is used.

That is, a stud 17 is provided upright on the lever 13, and the planetary gears 8, 10 are inserted into the stud 17.

Then, a disc spring (disc-shaped leaf spring) 18 is interposed between the stud 17 and the planetary gears 8, 10,
A predetermined load is applied to the planetary gears 8 and 10.

[Problem that the invention attempts to solve]

The planetary gear mechanism has the structure as explained above, but the structure of the support part where the lever supports the planetary gear has a large number of parts and is complex, and the problem is that it requires many man-hours to assemble and is expensive. It was hot.

[Means for solving problems]

FIG. 1a is a block diagram showing the planetary gear mechanism of the present invention.

The lever that rotatably supports the planetary gear is composed of a pair of arms separated by a slit, and a substantially semicircular holding part provided at the tip of each arm. It should be smaller than the outer diameter of the gear rotation shaft.

[Effect]

Since the inner diameter of the holding part provided on the pair of arms separated by the slit is set to be smaller than the outer diameter of the rotating shaft of the planetary gear, the shaft of the planetary gear attached to the holding part is , a load is applied so as to cause braking by the elasticity of the arm.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

Identical parts are designated by the same reference numerals throughout the figures.

In the present invention, as shown in FIG. A clamping means 22 as shown in FIG. 2B is provided for clamping the shafts 19a and 20a.

That is, the planetary gear mechanism 23 of the present invention, as shown in FIG. An idle gear 9 that meshes with the drive shaft gear 7, a second planetary gear 20 that faces the idle gear 9, a sun gear 11 that meshes with the first and second planetary gears 19, 20, and a first and second a lever 21 that brakes and supports the rotation of the planetary gears 19 and 20 and rotatably engages the shaft portion 12 of the sun gear 11; a pulley 15 and a rope 16 as means 14 for rotating the sun gear 11; When the sun gear 11 is rotated counterclockwise by the rotating means 14, the first and second planetary gears 19 and 20 rotate in the same direction as the sun gear 11, and the first planetary gear 19 rotates in the same direction as the sun gear 11. meshes with the drive shaft gear 7 to rotate the drive shaft 6 counterclockwise.

When the sun gear 11 is rotated clockwise, the second planetary gear 20 meshes with the idle gear 9 to rotate the drive shaft 6 counterclockwise via the drive shaft gear 7 in the same manner as described above. It is something.

The clamping means 22 for rotationally supporting the planetary gears is shown in detail in FIG. 1b.

The lever 21 is made of synthetic resin and is connected to the sun gear 11.
is rotatably supported on the same axis. The lever 21 is divided into a pair of arms 21c and 21d, and a holding portion 21a is formed at the tip of each arm 21c and 21d. The holding portion is approximately semicircular, and its inner diameter is the rotation shaft 19a of the planetary gear.
It is slightly smaller than the outer diameter of 20a.

Therefore, the rotation shaft of the planetary gear is held by the holding portion 21.
When attached to point a, each arm 21c and 21d opens slightly as shown by the two-dot chain line due to its elasticity and holds the shaft. Therefore, a drag force in the G direction is applied to the shaft of the planetary gear, and a braking force is applied to the planetary gear.

[Effect of idea]

As explained above, by using the planetary gear mechanism of the present invention, the number of parts can be reduced, assembly can be simplified, and many other economic and industrial effects can be achieved.

[Brief explanation of the drawing]

Fig. 1a is a block diagram showing the planetary gear mechanism of the present invention, Fig. 1b is an enlarged view of section A in Fig. 1a, Fig. 2 is a schematic diagram of a printer to which the conventional planetary gear mechanism is applied, and Fig. 3 Figures a and b are explanatory views of the operation of the planetary gear, and Figure 4 is an enlarged side view of the planetary gear holding section. In the figure, 5 and 23 are planetary gear mechanisms, 6 is a drive shaft, 7 is a drive shaft gear, 8 and 19 are first planet gears, 9 is an idle gear, 10 and 20 are second planet gears, and 11 is the sun gear, 12 is the shaft, 13, 21
is a lever, 14 is a rotating means, 15 is a pulley,
16 is a rope, 17 is a stud, 18 is a disc spring,
19a is the rotation shaft of the first planetary gear, 20a is the second
21a is a shaft bearing, 21b is a slit, 21c and 21d are arms, and 22 is a half shaft bearing.

Claims (1)

[Claims for Utility Model Registration] A drive shaft 6, a drive shaft gear 7 attached to the drive shaft 6, and a first planetary gear 19 facing the drive shaft gear 7.
and an idle gear 9 that meshes with the drive shaft gear 7.
and a second planetary gear 2 facing the idle gear 9
0, a sun gear 11 meshing with the first and second planetary gears 19 and 20, and braking and supporting the rotation of the first and second planetary gears 19 and 20; It consists of a pair of levers 21 rotatably engaged with the shaft portion 12, and a means 14 for rotating the sun gear 11, and when the sun gear 11 is rotated by the rotating means 14, the first and second levers are rotated. The first planetary gears 19 and 20 revolve in the same direction as the sun gear 11, the first planetary gear 19 meshes with the drive shaft gear 7 to rotate the drive shaft 6 in a predetermined direction, and the first planet gear 19 rotates in the opposite direction. When each lever 21 rotates, the second planetary gear 20 meshes with the idle gear 9 and rotates the drive shaft 6 in the same direction as the above-mentioned direction via the drive shaft gear 7. Each has a pair of elastic arms 21d and 21c separated by a slit 21b, and is provided at the tip of each arm 21d and 21c,
The holding portion 21a has a substantially semicircular shape, and the inner diameter of the holding portion 21a is equal to that of each of the planetary gears 1.
A planetary gear mechanism characterized in that the outer diameter is smaller than the outer diameter of the rotating shafts 19a and 20a of the rotating shafts 9 and 20.