JPH0322315B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blanket tensioning device used for stretching a blanket onto a blanket cylinder in a printing press.

In a printing press, as shown in FIG. 1, a plate cylinder 10 and a blanket cylinder 2 are used.
0 and an impression cylinder 30, and the plate cylinder 10 is attached with a dampening mechanism and an inking mechanism. A printing plate is attached to the plate cylinder 10, dampening water is applied to the non-image areas of the printing plate by a humidifying device, and ink is applied to the image areas by an inking device. This ink is transferred to the blanket cylinder 20 by further rotation of the plate cylinder 10. The blanket cylinder 20 transfers the ink passed from the plate cylinder 10 via the blanket B to a metal plate A or the like which is a printing medium. Impression cylinder 30
This cylinder and blanket cylinder 20
This applies the pressure necessary for ink transfer to the metal plate A passing between the two. Of the three cylinders of this printing press, blanket cylinder 20 is wrapped with blanket B.
It comes in contact with the plate cylinder 10 to receive ink from the printing plate, and further rotates to transfer the ink to the surface of the metal plate A between it and the impression cylinder 30. Among them, the blanket B plays this role directly, and in order to print the image accurately, it is necessary to always tension the blanket B in an appropriate state so that it does not loosen or sag on the blanket cylinder 20. Blanket B
The first step is to attach the cylinder to the blanket cylinder 20.
As shown in the figure, both ends of the blanket B are fixed to the blanket clamp shafts 2, and by rotating each clamp shaft 2, the blanket can be wrapped around the blanket cylinder 20 and tensioned. Conventionally, this blanket cylinder 20
The structure is such that the clamp shaft 2 is rotated via a worm when obtaining blanket B, but since the tension of blanket B depends on the individual worker's perception, adjustment by an expert is required, and even then, It was inevitable that individual differences would occur between workers, and it took time to make adjustments. For this reason, it is desired to develop a countermeasure technique that can easily and quickly tension a blanket to a desired tension without requiring skilled workers, and without causing individual differences among workers.

This invention was made in view of the above circumstances, and it prevents the transmission of excessive torque exceeding a set value, prevents excess tensile force from acting on the blanket, and maintains the tension of the blanket in a preset state. It is possible to easily detect when the blanket has reached the desired tension, and it is possible to easily and quickly tension the blanket to the desired tension without relying solely on skilled workers, and without causing individual differences among workers. The object of the present invention is to provide a blanket tensioning device for a printing press that can be used in a printing press.

Corresponding to this purpose, the blanket tensioning device for a printing press of the present invention places a blanket clamp shaft of a blanket cylinder of a printing press and a worm wheel in a rotational transmission relationship via a torque limiter, and extends the blanket from the worm wheel to the blanket. When the torque transmitted to the blanket clamp shaft exceeds a set value, the torque limiter limits the rotational transmission relationship between the blanket clamp shaft and the worm wheel within a certain rotation angle range corresponding to the length of the elongated hole. The torque limiter includes a first clutch plate in a rotation transmission relationship with the worm wheel and a second clutch plate in a rotation transmission relationship with the blanket clamp shaft, which face each other in the direction of the same rotational axis. and a locking member movable in the direction of the rotation axis, and the first clutch plate has an engaging portion formed at a predetermined radial position that can abut and engage with the locking member. , a second hole through which the locking member can pass is formed in the second clutch plate at the radial position, and the locking member straddles the engagement portion and the second hole. the first clutch plate and the second clutch plate are configured to be connected to each other by entering and exiting a connecting position where the clutch plate is connected;
The normal line of the contact surface when the engaging portion and the locking member are in contact with each other is inclined with respect to the rotation axis, and the engaging member is elastically pressed to the connection position. a pin is interposed between the second clutch plate and the worm wheel, the pin is fixed to either the second clutch plate or the worm wheel, and the second clutch plate is fixed to the second clutch plate or the worm wheel. By engaging with the elongated hole formed in the rotational direction in the other of either the clutch plate or the worm wheel,
It is characterized in that relative rotation between the second clutch plate and the worm wheel is allowed within the predetermined angular range corresponding to the length of the elongated hole.

The details of this invention will be explained below with reference to the drawings showing one embodiment.

In FIGS. 1, 2, and 3, 1 is a blanket tensioning device. The blanket tensioning device 1 includes a blanket clamp shaft 2 and a worm wheel 3, and the blanket clamp shaft 2 and the worm wheel 3 are placed in a rotation transmission relationship via a torque limiter 5. The torque limiter 5 includes a first clutch plate 6 and a second clutch plate 7 located coaxially and oppositely to the rotation axis of the blanket clamp shaft 2, and a locking member 8 movable in the direction of the rotation axis.
and a pressing member 9. As shown in FIG. 4, the first clutch plate 6 is fixed to the side surface of the worm wheel 3 and has an engaging portion 11 formed of a hole 12 penetrating in the direction of the rotation axis. The diameter d of this hole 12 is the diameter of a steel ball 23, which will be described later.
Therefore, the steel ball 23 cannot pass through. On the other hand, the second clutch plate 7 is mounted on the blanket clamp shaft 2 and is fixed to the blanket clamp shaft 2 by a key 13. Second clutch plate 7
has a hollow shaft portion 14 and a flange 15 formed at one end thereof. Shaft 1 of second clutch plate 7
A worm wheel 3 is rotatably mounted on the worm wheel 4 via a bearing 16. A worm 17 is engaged with the worm wheel 3. The worm 17 is attached to a worm shaft 19 supported by a bearing 18 in a fixed position. The second clutch plate 7 has an engaging portion 11 of the first clutch plate 6.
A hole 21 is formed at the same radial position as (hole 12) and penetrates in the direction of the rotation axis. The diameter D of this hole 21 is larger than the diameter R of a steel ball 23, which will be described later, so that the steel ball 23 can pass therethrough. Also, the thickness H of this flange 15 is the diameter R of the steel ball 23.
smaller than

The locking member 8 is made of a steel ball 23, is housed in the hole 21 of the second clutch plate 7, and is pressed by the pressing member 9 to the engaging part 11 (hole 1) of the first clutch plate 6.
2). And this locking member 8
The first clutch plate 6 and the second clutch plate 7 are connected to each other by moving in and out of the connecting position spanning the engaging portion 11 (hole 12) and the hole 21. The surface of the steel ball 23 is a curved surface, and when it comes into contact with the edge of the hole 12, the normal line of the contact surface is inclined with respect to the center line of the hole 12, so that the partial pressure in the direction of the center line of the contact pressure is It acts between the first clutch plate 6 and the steel ball 23. Here, the steel ball 23 is used in the first
This locking member 8 connects the second clutch plate 6 and the second clutch plate 7 and obtains a component of the contact pressure in the direction of the center line.
In addition to No. 3, other members having slopes capable of producing such a component of the contact pressure in the center line direction on the abutment surface can be used.

The pressing member 9 includes a pressing plate 25 having a thickness of t that faces the outside of the second clutch plate 7 and is in contact with the steel ball 23, and a disc spring 26 that presses the pressing plate 25.
and an adjustment screw 2 for adjusting the amount of predeformation of the disc spring 26
7.

A pin 29 is interposed between the second clutch plate 7 and the worm wheel 3. The pin 29 is fixed to the worm wheel 3 and the second clutch plate 7.
It engages with an elongated hole 31 formed in the direction of rotation. Therefore, as shown in FIG. 5, the second clutch plate 7 and the worm wheel 3 are free to rotate relative to each other within a predetermined angular range corresponding to the length of the elongated hole 31. Note that the pin 29 may be fixed to the second clutch plate 7, in which case the elongated hole 31 would be formed in the worm wheel 3.

Furthermore, the worm shaft 19 is provided with a reverse rotation prevention device 33.
is installed. As shown in FIGS. 6 and 7, the reverse rotation prevention device 33 includes two brake pieces 34, 35 that can be relatively displaced in a linear direction, and a screw member 36 that allows the two brake pieces 34, 35 to be relatively displaced. and the worm shaft 19 is sandwiched between the two brake pieces 34 and 35.
is configured to constrain.

Blanket tensioning device 1 configured in this way
The operations for blanket tensioning work are as follows. First, the adjustment screw 27 of the pressing member 9 is operated to adjust the amount of predeformation of the disc spring 26, and when the component of the contact pressure described later becomes larger than the elastic pressing force of the disc spring 26, the blanket is The steel ball 23 is elastically pressed against the edge of the hole 12 of the first clutch plate 6 with a predetermined contact pressure so that the tensile strength becomes a predetermined value. Next, worm shaft 1
When 9 is turned with a tool, the rotation is caused by the worm shaft 1
9, worm 17, worm wheel 3, first clutch plate 6, steel ball 23, second clutch plate 7,
The tension is sequentially transmitted to the blanket clamp shaft 2 via the key 13, and as the blanket clamp shaft 2 rotates, the blanket is gradually tensioned. Next, when the tension of the blanket reaches the set value, the component of the contact pressure between the steel ball 23 and the second clutch plate 6 in the direction of the center line of the hole 12 overcomes the pressing force of the disc spring 26. , the steel ball 23 is removed from the hole 12, and the second clutch plate 7 or the blanket clamp shaft 2 is free to rotate. At this time, the force applied to the worm 17 suddenly decreases (almost halved), which the operator can feel, and as shown in FIG. When the distance S between the clutch plate 7 and the push plate 25 becomes larger, the operator can know that the blanket tensioning is completed. On the other hand, pin 2 driven into worm wheel 3
9 is freely inserted into the elongated hole 31 of the second clutch plate 7, but when the steel ball 23 comes off and the second clutch plate 7 becomes free to rotate, as shown in FIG. The clutch plate 7 of 2 is slightly reversed, and the pin 2
9 approaches the end of the elongated hole 31 of the second clutch plate 7 and transmits force instead of the steel ball 23.

When the blanket tensioning work is completed, the reverse rotation prevention device is operated to clamp and fix the worm shaft 19 between the brake pieces 34 and 35.

In the blanket tensioning device for a printing press constructed in this manner, the pressure with which the steel ball 23 is pressed against the hole 12 of the first clutch plate 6 is set at a constant level by operating the adjustment screw 27 of the torque limiter 5. , the tension of the blanket gradually increases during the blanket tensioning operation, and the blanket tension when the clutch is released is always constant, and by ending the blanket tensioning operation when the clutch is released, the blanket tensioning operation can be adjusted. Individual differences between people will disappear.

Dislodging of the clutch during blanket tensioning work is caused by: (1) When tensioning the blanket, the worm shaft is rotated with a tool, but the force required to do so decreases rapidly once the clutch disengages. (About half.) (2) When the clutch is disengaged and the steel balls move, the gap between the second clutch plate 7 and the counter plate 25 becomes larger. (For example, 0.8mm→3.3mm) (3) The clamp shaft is reversed.

Workers can easily make judgments based on these facts.

The larger the amount of reversal of the clamp shaft, the easier it will be to confirm the above-mentioned clutch-off.
If the tension of the blanket is optimal at the time of clutch-off, the tension of the blanket will be loosened by the reversal of the clamp shaft.In order to minimize the amount of reversal of the clamp shaft, a pin 29 and a second pin are installed on the worm wheel. An elongated hole 31 is provided in the clutch plate, and the clamp shaft is held in a position reversed by the elongated hole, providing a mechanism for maintaining optimal blanket tension. Note that the size of the elongated hole is set to such an extent that it does not affect the blanket tension. As described above, in the blanket tensioning device of the present invention, if an excessive torque exceeding a set value is transmitted, the connection between the worm wheel and the blanket clamp shaft is cut off, and the tension of the blanket is maintained at the preset state. Since it is possible to easily detect when the desired tension has been reached, the blanket can be stretched to the desired tension easily without relying solely on skilled workers, and without causing individual differences among workers. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing a cylinder of a printing press, Fig. 2 is a front view of a blanket tensioning device according to an embodiment of the present invention, Fig. 3 is a longitudinal sectional view of the blanket tensioning device, and Fig. 4 shows a torque limiter. FIG. 5 is an explanatory diagram showing the connection between the worm wheel and the second clutch plate by a pin, and FIG.
The figure is a longitudinal sectional view of the anti-reverse device, Fig. 7 is a perspective explanatory view of the anti-reverse device, Fig. 8 is a longitudinal sectional view of the torque limiter, and Fig. 9 is a pin-based connection between the worm wheel and the second clutch plate. FIG. DESCRIPTION OF SYMBOLS 1... Blanket tensioning device, 2... Blanket clamp shaft, 3... Worm wheel, 5... Torque limiter, 6... First clutch plate, 7... Second clutch plate, 8... Locking member , 9... Pressing member, 10... Blanket cylinder, 11... Engaging portion, 12... Hole, 17...
Worm, 21...hole, 23...steel ball, 25...
Push plate, 26... disc spring, 33... reverse rotation prevention device.

Claims (1)

[Scope of Claims] 1. A blanket clamp shaft of a blanket cylinder of a printing press and a worm wheel are placed in a rotation transmission relationship via a torque limiter, and the torque transmitted from the worm wheel to the blanket clamp shaft is at a set value. The torque limiter is configured to interrupt the rotation transmission relationship between the blanket clamp shaft and the worm wheel within a certain rotation angle range corresponding to the length of the elongated hole when the torque exceeds the length of the elongated hole. a first clutch plate that is in a rotational transmission relationship with the worm wheel and a second clutch plate that is in a rotational transmission relationship with the blanket clamp shaft, and a lock that is displaceable in the rotational axis direction; the first clutch plate has an engaging portion formed at a predetermined radial position that can abut and engage with the locking member, and the second clutch plate has an engaging portion that can abut and engage with the locking member; A second hole through which the locking member can pass is formed at a position in the direction, and the locking member moves in and out of a connection position spanning the engagement portion and the second hole. The first clutch plate and the second clutch plate are configured to be discontinuously connected, and the normal line of the contact surface when the engaging portion and the locking member are in contact with each other is inclined with respect to the rotation axis. and a pressing device configured to elastically press the engagement member to the connection position, a pin being interposed between the second clutch plate and the worm wheel, and the pin being inserted into the connection position. By fixing it to either the second clutch plate or the worm wheel and engaging the elongated hole formed in the rotational direction in the other of the second clutch plate or the worm wheel. A blanket tensioning device for a printing press, characterized in that relative rotation between the second clutch plate and the worm wheel is allowed within the predetermined angular range corresponding to the length of the elongated hole. 2. The locking member is a steel ball, and the engaging portion penetrates the first clutch plate in the direction of the rotation axis at the same radial position as the second hole with a diameter smaller than the diameter of the steel ball. a first hole formed therein, and the pressing device includes a pushing plate that faces the outside of the second clutch plate and is in contact with the steel ball; a spring member that presses the pushing plate; A blanket tensioning device for a printing press according to claim 1, further comprising an adjusting member for adjusting the amount of predeformation of the spring member. 3. A reversal prevention device is attached to the worm shaft of the worm that meshes with the worm wheel, and the reversal prevention device includes two brake pieces that can be relatively displaced in a linear direction, and a screw member that allows the two brake pieces to be relatively displaced. Claim 1 or 2, characterized in that the worm shaft is restrained by sandwiching the worm shaft between the two brake pieces. blanket tensioning device for printing presses.