JPH084874A - Power transmission device - Google Patents

Abstract

PURPOSE:To reduce a manufacturing cost by connecting a motor as a driving source to a gear, providing a stopper on a bracket which holds the gear for positioning the bracket, and thereby dispensing with an idler gear and a tension roller. CONSTITUTION:In a power transmission device such as ink-ribbon driving device for a printer, gears 1 and 2 are meshed with each other at the closing time of a sub-frame. Rotation of a motor 9 is transmitted to the gear 2 through a belt 8 and the gear 1. When the sub-frame is released, meshing of the gears 1, 2 is released and the rotation of the motor 9 is not transmitted to the gear 2. A bracket 4 is rotated around a rotational center 12 by means of a spring 6. A stopper 10 is brought into contact with an edge of a main frame 11 for stopping motion of the bracket 4. The stopper 10 is so positioned in respect to the main frame 11 as to obtain optimum tensile force of the belt 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive source mounted on one frame of an apparatus, a driven section mounted on the other frame of the apparatus, and a frame on which the driven section is mounted. The present invention relates to a power transmission device used for transmitting power from a drive source to a driven part in a device having a structure that can be opened and closed with respect to a frame to which a drive source is attached.

[0002]

2. Description of the Related Art FIG. 2 is a front view showing an example of a conventional power transmission device.

For example, like an ink ribbon drive device in a printer, the drive source is attached to one frame of the device, the driven part is attached to the other frame of the device, and the driven part is attached. A conventional power transmission device used to transmit power from a drive source to a driven part in a device having a structure in which a frame to be opened and closed can be opened and closed with respect to a frame to which a drive source is attached has a structure as shown in FIG. have.

In FIG. 2, the bracket 24 is rotatably attached to the main frame 31 at a center of rotation 32, and an idler gear 23 is attached to the center of rotation 32. The gear 21 attached to the end of the bracket 24 meshes with the idler gear 23. The motor 29 is fixed to the main frame 31, and the rotation of the motor 29 is transmitted to the idler gear 23 by the belt 28. A tension roller 27 is provided on the side of the central portion of the belt 28 to apply tension to the belt 28. A spring 26 is attached to the end of the bracket 24 opposite to the end to which the gear 21 is attached.
6 acts in a direction to move the gear 21 toward the gear 22.

A gear 22 that meshes with the gear 21 is rotatably attached to a bracket 25.
Are fixed to subframes (not shown). This sub-frame can be opened and closed with respect to the main frame 31, and when the sub-frame is moved in the direction of the arrow B and opened, the bracket 25 has a reference numeral 25.
The gear 22 and the gear 21 are disengaged from each other at the position a.

In the conventional power transmission device configured as described above, when the subframe is moved in the direction of arrow A and closed, the gear 21 and the gear 22 mesh with each other.
Is transmitted to the gear 22 via the belt 28, the idler gear 23, and the gear 21, but when the subframe is moved in the direction of the arrow B and opened, the gear 22 and the gear 21 are rotated.
Since the meshing with the
2 will not be transmitted. When the tooth tips of the gear 21 and the gear 22 come into contact with each other when the subframe is closed again,
The bracket 24 rotates about the rotation center 32,
The gear 22 and the gear 21 are allowed to normally mesh with each other. At this time, a force is applied to the gear 21 in the direction of the gear 22 by the spring 26, so that both can be reliably meshed.

[0007]

As described above, since the conventional power transmission device requires the idler gear and the tension roller, the structure is complicated and the number of parts is large, so that the manufacturing cost is high. It has drawbacks.

[0008]

According to a first aspect of the present invention, there is provided a power transmission device having a stopper which is supported by a first frame with a central portion as a center of rotation and which is provided on one side surface of one end portion so as to contact the first frame. Bracket, a first gear rotatably attached to the other end of the first bracket, a motor fixed to the first frame, and the rotation of the motor transmitted to the first gear. The first belt to
A spring attached to the one end of the first bracket and acting in a direction to give tension to the first belt, and fixed to a second frame that can be opened and closed with respect to the first frame. A second bracket and a second gear that is rotatably attached to the second bracket and meshes with the first gear when the second frame is closed with respect to the first frame. It is equipped, and further
The second bracket is provided with an elongated hole for adjusting a fixed position with respect to the second frame.

[0009]

Embodiments of the present invention will now be described with reference to the drawings.

FIG. 1 is a front view showing an embodiment of the present invention.

In FIG. 1, a bracket 4 is rotatably attached to a main frame 11 at a center of rotation 12 and a gear 1 is rotatably attached to an end of the bracket 4. . The motor 9 is fixed to the main frame 11, and the rotation of the motor 9 is
It is transmitted to the gear 1 by the belt 8. A spring 6 is attached to the end of the bracket 4 opposite to the end to which the gear 1 is attached, and the spring 6 acts in a direction to apply tension to the belt 8. A stopper 10 formed by bending and bending a part of the bracket 4 is provided on the upper side surface of the end of the bracket 4 on which the spring 6 is mounted, and the stopper 10 serves as an edge of the main frame 11. By making contact, the movement of the bracket 4 is stopped.

A gear 2 meshing with the gear 1 is rotatably attached to a bracket 5, and the bracket 5 is fixed to a sub-frame (not shown). This sub-frame can be opened and closed with respect to the main frame 11. When the sub-frame is moved in the direction of the arrow B and opened, the bracket 5 is at the position of the reference numeral 5a and the gear 2 and the gear. The mesh with 1 disengages. Bracket 5
The mounting position of the sub-frame on the sub-frame can be adjusted by the slot 13.

Next, the operation of the power transmission device configured as described above will be described.

When the sub-frame is moved in the direction of arrow A and closed, the gear 1 and the gear 2 mesh with each other, so that the motor 9
Is transmitted to the gear 2 via the belt 8 and the gear 1, but when the subframe is moved in the direction of the arrow B and opened, the gear 2 and the gear 1 are disengaged from each other. Will not be transmitted to gear 2. At this time, the bracket 4 rotates in the direction of arrow C around the rotation center 12 by the force of the spring 6, the stopper 10 comes into contact with the edge of the main frame 11, and the movement of the bracket 4 stops. The position of the stopper 10 with respect to the main frame 11 is set so that the tension of the belt 8 at this time is in an optimum state.

When the tooth tips of the gear 1 and the gear 2 come into contact with each other when the subframe is closed again, the bracket 4 rotates about the rotation center 12 so that the gear 2 and the gear 1 normally mesh with each other. To be able to At this time, a force is applied to the gear 1 in the direction of the gear 2 by the spring 6, and the belt 9 is rotated by the rotation of the motor 9.
Since the rotation is transmitted to the gear 1 via the
And 2 can be positively engaged. The backlash of meshing of the gears 1 and 2 can be adjusted to an optimum value by adjusting the mounting position of the bracket 5 by the elongated hole 13.

[0016]

As described above, in the power transmission device of the present invention, the motor of the drive source is directly connected to the first gear without relaying the idler gear, and the first gear is held. Positioning the first bracket by providing a stopper on one bracket, and setting the position of the stopper with respect to the main frame so that the tension of the belt connecting the motor and the first gear at that time becomes the optimum value. As a result, there is an effect that the idler gear and the tension roller can be removed, and therefore, there is an effect that the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention.

FIG. 2 is a front view showing an example of a conventional power transmission device.

[Explanation of symbols]

 1 ・ 2 ・ 21 ・ 22 Gear 4,5 ・ 24 ・ 25 Bracket 6 ・ 26 Spring 8 ・ 28 Belt 9 ・ 29 Motor 10 Stopper 11 ・ 31 Main frame 12 ・ 32 Rotation center 13 Long hole 23 Idler gear 27 Tension roller

Claims (2)

[Claims] 1. A first bracket, which is supported by a first frame with a central portion as a center of rotation and has a stopper that is in contact with the first frame on a side surface of one end portion, and the other of the first brackets. A first gear rotatably attached to an end, a motor fixed to the first frame, a first belt for transmitting the rotation of the motor to the first gear, the first gear A spring attached to the one end of the bracket and acting in a direction to apply tension to the first belt, and a second bracket fixed to a second frame that can be opened and closed with respect to the first frame. When,
A second gear that is rotatably attached to the second bracket and that meshes with the first gear when the second frame is closed with respect to the first frame. Power transmission device. 2. A first bracket, which is supported by the first frame with a central portion as a center of rotation, and has a stopper on one side surface that comes into contact with the first frame, and the other of the first bracket. A first gear rotatably attached to an end, a motor fixed to the first frame, a first belt for transmitting the rotation of the motor to the first gear, the first gear A spring that is attached to the one end of the bracket and acts in a direction that gives a tension to the first belt, and the second frame that is fixed to a second frame that can be opened and closed with respect to the first frame. A second bracket having an elongated hole for adjusting a fixed position with respect to the first bracket, and the second bracket rotatably attached to the second bracket when the second frame is closed with respect to the first frame. One A power transmission device comprising: a gear and a second gear that meshes with the gear.