JPS6137861Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a clutch mechanism used in printing devices and the like.

Conventionally, the printing head conveying means in a printing device has been configured to perform printing by sliding the printing head in the left-right direction using the driving force of a motor via a reduction gear train or a clutch mechanism.

By the way, the conveying means for the print head in this printing device prints within a predetermined width on the printing paper, so when one line of printing is finished, the clutch mechanism is instantly released, and the conveying means automatically returns to the home page. It was meant to move to a different position. The structure of the clutch mechanism in this case is such that the two clutch gears mesh with each other through teeth provided on opposing surfaces of the two clutch gears in order to achieve printing positional accuracy. .

However, when one line of printing is finished, if the clutch mechanism does not release due to some malfunction, the driving force of the drive motor will still try to move the conveying means, and in the worst case, the clutch gear teeth There was a risk of an accident causing damage to the parts.

The present invention eliminates the above drawbacks and includes:
An embodiment in which the present invention is applied to a printing device will be described below.

FIG. 1 shows the entire printing device. Both ends of guide shafts 3 and 4 are fixed between the base plates 1 and 2 on both sides, and the conveyance device 5 of the printing head can freely slide on this guide shaft. It is attached to. A printing head (not shown) is mounted and fixed on the upper part of the conveyance device 5, so that it can print on the recording paper inserted between it and the platen 6 via a ribbon. It's getting old.

By the way, both ends of the cable 7 are tied to the conveyance device 5. The cable 7 is passed around a pulley 8 rotatably attached to the base plates 1 and 2, and
A part of it is wound around one spiral guide groove 10 formed on the feed drum 9. Also, a return spring 11 is provided at one end (left side) of the conveyance device 5.
One end of the transport device is locked, and serves to return the transport device to the home position. and pulley 1
This return spring 11 is hung around 2.

By the way, the rotational drive mechanism of the feed drum 9 is as follows. In other words, the drive pinion 1 of the drive motor
A gear 14 for deceleration meshes with the gear 3, and a small gear 15, which is provided coaxially with this gear and rotates in conjunction with the gear, is connected to the gear 16 of the feed drum 9 via the clutch mechanism A.
It is designed to rotate.

Therefore, regarding the detailed structure of clutch mechanism A,
This will be explained with reference to FIG.

A solenoid 17 is fixed to the inside of the main plate 2, and one end of a return spring 19 that applies a spring force in a direction to move the operating shaft backward is attached to one end (left side) of an operating shaft 18 that passes through the solenoid. It is locked and the operating shaft is pulled. Actuation axis 18
The other end passes through the base plate 2, and a boss 20, a fixed clutch gear 21, and a movable clutch gear 22 are rotatably supported in order on this operating shaft. A clutch receiver 23 for regulating the position of the moving clutch gear 22 is mounted on the outside of the moving clutch gear 22, and cannot be removed from the operating shaft 18. In this way, the solenoid 1 is installed inside the main plate 2.
7, and the fixed clutch gear 21 and movable clutch gear 22 are provided on the outside, the positional space of the clutch mechanism A can be reduced. A fixed clutch gear 21 and a moving clutch gear 22
A clutch spring 25 is interposed between the clutch gears and the clutch gears to apply a repulsive force to each other. The opposing surfaces of both fixed clutch gears 21 and 22 are provided with tooth portions 26 and 2 that can engage and disengage each other and have a triangular cross section as shown in the third figure.
7 are formed, and are always in meshing and interlocking relationship. The spring force of the clutch spring 25 is equal to that of the return spring 1.
When the solenoid 17 is energized, the operating shaft 18 is lower than the spring force of the return spring 19.
It is possible to protrude against the spring force of , that is, to move to the right in FIG.

When the printing device starts a printing operation, the driving force of the driving pinion 13 rotationally drives the feed drum 9 via the gears 14, 15, the fixed clutch gear 21, and the movable clutch gear 22 of the clutch mechanism A.
Therefore, the cable 7 moves the conveying device 5 in the direction of arrow a in FIG. 1 in synchronization with the printing operation, and the moment the final printing is completed, the solenoid 17 is energized. Therefore, the operating shaft 18 of the solenoid 17 moves to the right in FIG. 2 against the spring force of the return spring 19, so that the movable clutch gear 22
It moves to the right due to the spring force of (the state shown by the chain line). Therefore, the movable clutch gear 22 is disengaged from the fixed clutch gear 21 and becomes free. When the moving clutch gear 22 becomes free, the feed drum 9 naturally becomes free, so the spring force of the return spring 11 moves the conveying device 5 in the direction opposite to the direction of arrow a, returning to the original position. to return to.

The above is a case where the solenoid 17 is operating normally. However, if the solenoid 17 does not operate due to a failure, the conveyance device 5 will not be able to receive the output from the drive pinion 13 even if it reaches the final printing position. It tries to move further to the right (in the direction of the arrow) due to the driving force. However, the transport device 5 cannot move any further in the direction of arrow a. Therefore, even in an abnormal situation where the rotational driving force of the drive pinion 13 is greater than the spring force of the return spring 19 minus the spring force of the clutch spring 25 and an excessive load is applied, the fixed slip gear 21 and the movable slip gear 22 The teeth 26 and 27, each having a triangular cross section, rotate idly because the movable clutch gear 22 moves to the right against the spring force of the return spring 19 due to the slope of the teeth. Therefore, damage to the tooth portions 26 and 27 of both clutch gears 21 and 22 is prevented. The meshing force of the teeth 26 and 27 or the torque value for releasing the meshing force can be freely changed by selecting the spring force of one or both of the return spring 19 and the clutch spring 25. Note that the solenoid 17 may be of a type that includes a built-in return spring 19 that urges the actuating shaft 18 in a backward direction. In such a type of solenoid, its actuation shaft would protrude through it at only one end.

As described above, according to the present invention, in the event of an abnormal situation where an excessive load is applied, the meshing of the clutch gear is disengaged to prevent damage to the teeth, and the torque value for disengaging the meshing can be determined by selecting the spring force. It has the effect of being able to be changed freely.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the printing device, FIG. 2 is a sectional view of the clutch mechanism, and FIG. 3 is a front view of the clutch gear. A...Clutch mechanism, 17...Solenoid, 1
8... Operating shaft, 19... Return spring, 21... Fixed clutch gear, 22... Moving clutch gear, 23
...Clutch bridge, 25...Clutch spring, 26,
27...Tooth part.

Claims (1)

[Claims for Utility Model Registration] A solenoid is provided with an actuating shaft that is pushed in a backward direction by the spring force of a return spring and protrudes against the spring force of the return spring when energized; A pair of clutch gears having removable teeth with a triangular cross section are rotatably received on the operating shaft, and a clutch spring is inserted between the two clutch gears to bias the clutch gears in a direction of separation, A clutch receiver for regulating the position of the outer clutch gear is provided at the end of the operating shaft, and the spring force of the clutch spring is weaker than the spring force of the return spring and in a non-energized state, the spring force of the return spring and the above A clutch mechanism characterized in that the clutch gear is engaged due to a difference in spring force between the clutch spring and the clutch spring.