JPH0629545Y2 - Breaking device for feeding clutch - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a brake device for a paper feed clutch applied to a paper feed device such as a printer, and particularly to prevent excessive rotation due to rotational inertia of a clutch disc. The present invention relates to a brake device.

[Conventional technology]

A printer is one of the output devices of a computer system, an office automation system, etc., and is known from Japanese Patent Laid-Open No. 1780/1980.

FIG. 4 shows an external view of this type of printer. Reference numeral 1 is a printer unit, and 2 is an automatic paper feeding unit detachably set on the printer unit 1.

In the automatic paper feeding unit 2, the driving force for feeding the paper (not shown) housed in the first magazine 3 to the platen portion (not shown) of the printer unit 1 and the paper for which printing is completed are performed. The driving force for sending out to the second magazine 4 is given from a driving source (not shown) built in the printer unit 1, and the control command for sending these is also given from the printer unit 1.

However, the sheet feeding from the first magazine 3 to the platen is performed by a sheet feeding roller (not shown) provided in the printer unit 1, and the line feeding after being pinched by the platen of the printer unit 1 is performed. The sheet is discharged to the second magazine 4 by the normal rotation operation of the platen. It is necessary to separate the driving force of the platen from the drive system so that the driving force of the platen is not transmitted to the paper feed roller until the printing and discharging processes are completed after the platen has been held. That is, when the paper feed roller is continuously driven after holding the paper in the platen, the front side of the paper is fed to the platen and the back side of the paper is fed by the paper feed roller, so that the peripheral speeds of the platen and the paper feed roller are accurately measured. If they do not match, the print may not be clean or the paper may run out. Furthermore, the paper end is
When the paper is separated from the paper feed roller, the next paper is fed out, and the subsequent steps cannot be performed accurately. For this reason, the paper feed roller is separated from the drive system, and when the paper is fed by the platen, the paper feed roller rotates along with the feeding of the paper. A unidirectional clutch is generally used to separate and contact the paper feed roller and the drive system (see Japanese Patent Laid-Open No. 60-101326).

5 to 7 show a conventional clutch disclosed in Japanese Patent Laid-Open No. 60-101326 and the like.
Reference numeral 5 denotes a paper feed shaft rotatably attached to the paper feeding unit 2. A drive disc 6 is rotatably attached to the feed shaft 5, and the drive disc 6 and a gear train 7 connected to a platen. It is equipped with a meshing gear 6a.
Reference numeral 8 denotes a clutch disc rotatably attached to the feed shaft 5 in the vicinity of the drive disc 6, and a claw hole 8a is formed in the outer peripheral wall of the clutch disc 8.
A ratchet pawl 9 attached to the drive disc 6 is recessed into the inside a, and the ratchet pawl 9 is constantly pressed against the outer peripheral surface of the clutch disc 8 by a spring (not shown). A drive gear 10 located inside the clutch disc 8 and locked by the ratchet pawl 9 is fixed to the feed shaft 5. The drive disk 6 is constantly rotating in accordance with the normal and reverse directions of the printer body, and the ratchet pawl 9 is engaged with the drive gear 10 by the normal rotation until the sheet is fed from the first magazine 3 to the platen ( The clutch disc 8 disengages the ratchet pawl 9 and the drive gear 10 (clutch disengagement) for normal and reverse rotations at other times, but the clutch disc 8 is not in contact with the clutch disc 6. Ratchet pawl 9 is clutch disc 8
Since it rotates in contact with the outer peripheral surface of the drive disk 6, when the drive disk 6 rotates unnecessarily, or when the rotation is reversed, excessive rotation due to inertia causes the relative positions of the ratchet pawl 9 and the pawl hole 8a to shift, and the clutch connection, Since the disengagement becomes inaccurate and the paper cannot be fed, a brake mechanism for preventing the clutch disk 8 from over rotating is attached. That is, as shown in FIG. 7, when the drive disk 6 normally rotates in the Y direction, since the clutch disk 8 receives the braking force by the brake 11, the ratchet pawl 9 passes through the idling allowance zone I. The rotation is stopped until it comes into contact with the stopper 8b.
When the ratchet pawl 9 contacts the stopper 8b and the drive disk 6 further rotates in the Y direction, the clutch disk 8
Is rotated against the braking force of the brake 11, but the drive shaft 6 is not rotated (clutch disengaged) because both the drive disc 6 and the clutch disc 8 are loosely fitted to the feed shaft 5. The ratchet pawl 9 is in contact with the stopper 8b, so that the ratchet pawl 9 and the pawl hole 8a as a so-called home position are rotated in this state.
The space angle θ _{1 between and} is maintained. Next, when the drive disc 6 reverses by θ _{1 in the} X direction, the ratchet pawl 9 is deflected by the turning surface 8c of the clutch disc 8 which has stopped due to the braking force of the brake 11, and the ratchet pawl 9 is projected into the pawl hole 8a and the tip thereof is fed to the feed shaft 5. It engages with the tooth 10a of the drive gear 10 fixed to. Then, the drive disk 6 which is reversed in the Y direction
Drives the drive gear 10 together with the clutch disc 8 through the ratchet pawl 9 against the braking force of the brake 11 to rotate (clutch joint) the sheets housed in the first magazine 3 into the printer unit 1. Send it to the platen section. Further, when the rotational drive force to the drive gear 10 is cut off, the clutch disc 8 stops rotating due to the braking force of the brake 11, so the drive disc 6 is reversed in the X direction by θ ′, and then θ _{2 by} Y. If the ratchet pawl 9 is rotated in the normal direction, the ratchet pawl 9 returns to the home position. Further, the brake shoe 11 is formed of a bar-shaped member, and a substantially middle portion thereof is pivotally attached to a fixed portion by a pin 12, and a coil spring 14 is hooked between one end thereof and the fixed pin 13. Thus, the other end of the brake shoe 11 is pressed against the outer peripheral surface of the clutch disc 8 to prevent the clutch disc 8 from excessively rotating.

[Problems to be solved by the device]

In the conventional brake device for a sheet feeding clutch as described above, the brake shoe 11 is pressed against the clutch disc 8 from one direction and is pressed from a position deviated from the pivotal support portion of the clutch disc 8. Therefore, the pressing force also acts directly on the feed shaft 5, and a considerably large frictional resistance is generated between the feed shaft 5 and the clutch disc 8 fitted and supported by the feed shaft 5, which causes the drive load of the paper feeding unit. Making it big.

Also, in the printer, a small output motor of, for example, about 80 to 150 gr ^- cm is used as the platen drive motor for cost reduction, compactness, and weight reduction. The increase in the load on the motor causes the motor to become overloaded, resulting in overheating of the motor and beat noise.

The present invention solves the above problems and eliminates the braking pressure of the brake shoe against the clutch disc from acting on the pivotal support portion of the clutch disc, and reduces the load on the drive motor. It is intended to provide.

[Means for Solving the Problems]

A brake device for a sheet feeding clutch according to the present invention is a sheet feeding unit with a unidirectional clutch for intermittently feeding a sheet to a predetermined position, and a drive disk in which the unidirectional clutch is rotatably attached to a sheet feeding shaft. A relative position of the drive disk to the pawl, a clutch disk rotatably provided on the paper feed shaft adjacent to the drive disk, and a ratchet pawl of the drive disk fixed to the paper feed shaft. The drive gear engages through the clutch disc, and a pair of brake shoes that press-contact the outer peripheral surface or the inner peripheral surface of the clutch disk from opposite diametrical directions. The pair of brake shoes are a common fulcrum. It is axially supported by and is symmetrical with respect to this fulcrum, and is uniformly biased in one direction by one biasing means. Is composed of a pressing force so as to generate said clutch disc, compared paper feed shaft,
It is loosely fitted with a gap provided, and a constant pressing force that is even and always opposite to each other from the pair of brake shoes is due to the frictional force between the ratchet pawl and the clutch disc and the frictional force between the clutch disc and the drive disc. The pressing force is always larger than the sum, and is always applied to the clutch disc, and the pressing force keeps the rotating shaft core of the clutch disc aligned with the shaft center of the paper feed shaft, and the clutch disc has a gap with respect to the paper feed shaft. It is configured to be held at a uniform interval.

[Function of device]

In the present invention, since the pair of brake shoes uniformly generate a constant pressing force in the opposite directions by one urging means, the pressing force is constantly applied to the outer peripheral surface of the clutch disc or the inner peripheral surfaces facing each other in the diametrical direction. The sliding contact prevents the braking force of the brake shoe against the clutch disc from acting on the pivotal support portion of the clutch disc, and the frictional resistance of the pivotal support portion of the clutch disc does not increase. Also, in order to prevent the braking force from acting as bending stress on the paper feed shaft, a uniform braking pressure is applied to the clutch disc in the diametrical direction at all times so that there is a gap between the paper feed shaft and the clutch disc to prevent deviation. Can be supported by.

[Example of device]

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

1 and 2 show an example of a brake device for a paper feeding clutch according to the present invention. In the figure, the same parts as those in FIGS. 5 to 7 are designated by the same reference numerals, and the description thereof will be omitted.
The points different from those in FIGS. 5 to 7 will be mainly described.

That is, in this embodiment, the braking force applied to the clutch disc 8 of the brake device is prevented from acting on the pivot portion of the clutch disc 8. Therefore, the brake device for preventing the clutch disc 8 from over-rotating has a pair of L-shaped brake shoes 15, 16 and one end portion 15a, 1 of the L-shaped brake shoes 15, 16.
6a are overlapped with each other, and the middle portion thereof is connected to the pivot pin 1
7, the other end portions 15b and 16b are arranged so as to be rotatably pivoted to a fixed portion (sheet feeding unit main body), and slidably contact the outer peripheral surface of the clutch disk 8 from the diametrical direction opposite to each other. Both ends of the tension coil spring 18 are connected between the free ends of 15a and 16a, so that the other ends 15b and 16b of the L-shaped brake shoes 15 and 16 are pressed against the outer peripheral surface of the clutch disc 8 with a predetermined pressure. The clutch disc 8 is applied with a braking force for preventing over-rotation.

In the above embodiment, the other ends 15b and 16b of the L-shaped brake shoes 15 and 16 contact the outer peripheral surface of the clutch disc 8 from the diametrical direction at the same pressure. The braking pressure of the L-shaped brake shoes 15, 16 is hardly applied to the rotation pivotally supporting surface of the clutch disc 8 with the feed shaft 5, and the L-shaped brake shoes 15, 16 are pressed against the clutch disc 8. Even if the position is deviated from the pivotal portion, the clutch discs 8 loosely fitted to the feed shaft 5 are held concentrically with the axial center of the feed shaft 5 because they slidably contact the opposite sides in the diametrical direction with the same pressure. At the same time, since the clutch disc 8 is supported by the feed shaft 5 with a uniform gap, even if the feed shaft 5 and the clutch disc 8 respectively rotate, the L-shaped brake shoe 15 does not generate rotational shake. 16 the pressing force of without acting on the feed shaft 5 via the clutch disc 8, it becomes equal to the absence of L-shaped brake shoe 15, 16. Accordingly, the frictional force due to the braking force of the L-shaped brake shoes 15 and 16 is eliminated at the pivot portion of the clutch disc 8, the driving force of the sheet feeding unit becomes smaller than that of the conventional one, and the platen driving motor of the printer is excessively driven. It is possible to prevent overheating and roaring noise that are not applied by a heavy load.

FIG. 3 shows another embodiment of the brake device of the present invention. In this embodiment, the L-shaped brake shoe 15,
Protrusions 19 and 20 for pivotal attachment are provided on one end side of 16 so as to protrude inward, and the ends of the protrusions 19 and 20 are pivotally attached to a fixed portion by a pin 21 and also have an L-shape. At the other ends of the brake shoes 15 and 16, shoe parts 15c and 16c, which are in sliding contact with the inner peripheral surface of the clutch disc 8, are formed.
Both ends of the tension coil spring 18 are connected between one ends of the L-shaped brake shoes 15 and 16 on the 9 and 20 side so that the above-mentioned shoe parts 15c and 16c are pressed against the inner surfaces of the clutch disc 8 facing each other. It was done. In the figure, the same reference numerals as those in FIG. 1 denote the same parts.

In this embodiment, L-shaped brake shoes 15, 1
Although the method of press-contacting the clutch disk 6 of 6 is different, the same effect as that of the embodiment is obtained in FIG.

[Effect of device]

As described above, according to the present invention, the drive disc in which the one-way clutch is rotatably attached to the paper feed shaft and the relative position to the claw of the drive disc are held, and the drive disc is rotatably attached to the paper feed shaft. An adjacent clutch disc, a drive gear fixed to the paper feed shaft and engaged through the ratchet claw of the drive disc and the clutch disc, and the outer peripheral surface or the inner peripheral surface of the clutch disc are pressed and slid from the opposite diametrical directions. It has a pair of brake shoes, and the pair of brake shoes are axially supported by a common fulcrum, and are symmetrical with respect to this fulcrum, and are uniformly biased in one direction by one urging means. The clutch disc is loosely fitted to the paper feed shaft with a gap between the pair of brake discs. The constant pressing force, which is more uniform than that of the clutch and always in the opposite directions, is a pressing force that is greater than the sum of the frictional force between the ratchet pawl and the clutch disc and the frictional force between the clutch disc and the drive disc. , Due to the pressing force against the axis of the paper feed shaft,
Since the clutch disc is configured to hold the rotary shaft cores in line with each other and to keep the gap between the clutch disc and the paper feed shaft at even intervals, the braking pressure of the brake shoe against the clutch disc is applied to the pivot portion of the clutch disc. Since the driving force of the paper feeding unit can be reduced without acting, and the relative positional relationship between the clutch disc and the ratchet pawl is maintained, the clutch can be accurately engaged and disengaged.

[Brief description of drawings]

FIG. 1 is a front view showing an example of a brake device for a sheet feeding clutch according to the present invention, and FIG. 2 is a side view of a partial cutout thereof,
FIG. 3 is a front view showing another embodiment of a brake device for a paper feeding clutch according to the present invention, FIG. 4 is an external view of a printer having a paper feeding unit, and FIG. 5 is a conventional paper feeding clutch. FIG. 6 is a front view of the brake device, FIG. 6 is a side view of a part of the brake device, and FIG. 7 is a corresponding explanatory view of the ratchet pawl and the clutch disc when the home position is shifted. 1 ... Printer unit, 2 ... Automatic paper feeding unit, 5
…… Feed shaft, 6 …… Drive disk, 7 …… Gear train,
8 ... Clutch disc, 9 ... Ratchet claw, 10 ...
... drive gear, 15, 16 ... L-shaped brake shoe, 17 ... pivot pin, 18 ... tension coil spring.

Claims (1)

[Scope of utility model registration request] 1. A paper feed unit with a one-way clutch for intermittently feeding a sheet to a predetermined position, a drive disk having the one-way clutch rotatably attached to a paper feed shaft, and a claw of the drive disk. A clutch disc that is held in a relative position and is rotatably provided on the paper feed shaft and adjacent to the drive disc, and a drive gear that is fixed to the paper feed shaft and is engaged with the ratchet pawl of the drive disc and the clutch disc. And a pair of brake shoes that press-contact the outer peripheral surface or the inner peripheral surface of the clutch disk from opposite diametrical directions, and the pair of brake shoes are pivotally supported at a common fulcrum. It is symmetrical with respect to the fulcrum, so that a single biasing means can evenly generate a constant pressing force in opposite directions. The clutch disc is loosely fitted to the paper feed shaft with a gap, and a constant pressing force is applied to the ratchet pawl and the clutch by the pair of brake shoes evenly and always in opposite directions. A pressing force that is larger than the sum of the frictional force between the disc and the frictional force between the clutch disc and the drive disc, and is constantly applied to the clutch disc, and the pressing force causes the rotation axis of the clutch disc with respect to the axis of the paper feed shaft. A sheet feeding clutch brake device, characterized in that the cores are held together and the clutch discs are arranged so as to maintain a uniform gap with respect to the paper feed shaft.