Safety device for ink forming rollers

In a safety device for ink forming rollers, each of the rollers is supported on a frame through a moving shaft movable in an axial direction to remove the ink forming roller, a safety pin is provided which is urged and supported on the frame, the moving shaft is formed with a recess for engagement with the safety pin and guide surface for guiding the safety pin to the recess against the urging force of the safety pin. When the ink forming roller is mounted, the safety pin automatically engages to interrupt movement of the moving shaft, thereby preventing the ink forming roller from falling down due to an external cause such as a power stoppage or a misoperation, and the safety device being prevented from careless locking failure, thereby improving the safety of the printing machine.

FIELD OF THE INVENTION 
This invention relates to a safety device for ink forming rollers which 
contact the outer peripheral portion of a plate cylinder to apply ink 
thereto. 
BACKGROUND OF THE INVENTION 
A printing machine is equipped with a sheet feeder, a printing unit, a 
paper discharge device, and an ink unit, and this printing unit is in 
contact with a blanket cylinder, an impression cylinder, a transfer 
cylinder, a plate cylinder and the like, and supported on a shaft. The 
inking unit is provided with a group of rollers including ink forming 
rollers corresponding to the plate cylinder, and ink fountains. 
A plurality of the ink forming rollers contact a single plate cylinder, 
individually applying ink of different colors to the plate cylinder. The 
ink forming rollers are provided with patterns according to the printed 
matter, and, therefore must be replaced when the printed matter is changed 
or the roller surface is worn out. 
Prior art ink forming rollers are rotatably supported on the frames, and 
one end of each cylinder is supported by a moving shaft which is supported 
on the frames and movable in the axial direction. The moving shaft is 
mounted with a hydraulic cylinder to which a hydraulic pump is connected. 
The ink forming rollers are replaced by operating the hydraulic cylinder 
to move the moving shaft, allowing removal of the ink forming rollers from 
the frames. 
Such ink forming rollers are removed by moving the moving shaft in the 
axial direction by means of the hydraulic cylinder. Therefore the 
positional holding of the ink forming rollers depends on the hydraulic 
cylinder. If the hydraulic pump stops due to a power failure or the like, 
the pressure of the hydraulic cylinder decreases. As a result, the 
retaining force on the moving shaft, and, in turn, on the ink forming 
rollers is decreased, and the ink forming rollers can fall down from the 
frames due to their weight. 
Furthermore, since the operation of the hydraulic cylinder is controlled by 
the pressing of a button by an operator, if the operator presses the 
button by mistake during operation of the printing machine, there may 
occur defective printing or damage to the ink forming rollers or even 
damage to the printing machine. 
To prevent this, a safety pin has been provided in order to prevent the ink 
forming rollers from falling down even when the hydraulic pump stops or 
due to the operator's misoperation. Therefore, when the ink forming 
rollers are mounted, this safety pin is moved by the operator to lock the 
ink forming rollers, thereby retaining the ink forming rollers in 
position. When the safety pin is moved to an unlock position to unlock the 
ink forming rollers, the rollers can then be replaced. 
Such a safety pin is provided to prevent the ink forming rollers from 
falling down due to a stoppage of the hydraulic pump or the operator's 
misoperation. However, since the safety pin is operated manually by the 
operator, the operator may fail to move the pin to the lock position when 
the ink forming rollers are mounted. In such a case, the ink forming 
rollers cannot be prevented from falling down due to a stoppage of the 
hydraulic pump or the operator's misoperation, and the ink forming rollers 
or even the printing machine may be damaged. 
SUMMARY OF THE INVENTION 
With a view to eliminate such prior art problems, it is a primary object of 
the present invention to provide a safety device for ink forming rollers, 
which positively prevents the ink forming rollers from falling down for 
improving the safety of the printing machine. 
In accordance with the present invention, there is provided a safety device 
for ink forming rollers which are rotatably disposed in contact with the 
outer peripheral surface of a plate cylinder, one end being supported on a 
frame through a moving shaft, and detachable from the frame by moving the 
moving shaft in an axial direction, comprising a safety pin provided on 
the frame and urged in a direction to engage into the moving shaft, the 
moving shaft being formed with a recess for engagement with the safety pin 
and a guide surface for guiding the safety pin to the recess against the 
urging force when mounting the ink forming rollers. 
When the ink forming rollers are mounted, the guide surface of the moving 
shaft moves the safety pin against the urging force to automatically guide 
the safety pin to the recess in the moving shaft. Therefore, the safety 
pin prevents the moving shaft from moving in the axial direction due to an 
external cause such as a power stoppage or the like, thereby preventing 
the ink forming rollers from falling down. Furthermore, when the ink 
forming rollers are replaced, the safety pin can be removed from the 
moving shaft against the urging force, making the moving shaft movable in 
the axial direction and the ink forming rollers replaceable.

DETAILED DESCRIPTION OF THE INVENTION 
An embodiment according to the present invention will now be described in 
detail with reference to the drawings. 
As shown in FIG. 2, a plurality of ink forming rollers 3 are supported on 
shafts in contact with a plate cylinder 2 which is supported on a frame 1 
of a printing machine. Each of the ink forming rollers 3 is provided with 
a safety device 4. 
Referring to FIG. 3, one end of the ink forming roller 3 is rotatably 
supported on one frame by a supporting shaft (not shown) and the other end 
is supported on the frame 1 by an axially movable shaft 5. 
Specifically, a cylindrical connecting member 6 is fixedly mounted to the 
said other end of the ink forming roller 3, and a tapered bore 7 is formed 
in the connecting member 6. A cylindrical member 8 engages with the outer 
periphery of the moving shaft 5 and supports a disk 9 at its end. The 
cylindrical member 8 is supported by a sleeve 10 mounted in the frame 1. 
An axial grove 11 is formed on the outer periphery of the cylindrical 
member 8, and a key 12 is fixed to the inner periphery of the sleeve 10. 
The key 12 engages with the groove 11 to support the cylindrical member 8, 
and in turn the moving shaft 5, so as to be movable in the axial direction 
relative to the sleeve 10, but unrotatable in the circumferential 
direction. 
The moving shaft 5 is integrally formed with an engaging portion 13 for 
engagement with the tapered portion 7 of the connecting member 6. A 
hydraulic cylinder 14 is supported by the frame 1, and the front end of a 
connecting rod 15 of the hydraulic cylinder 14 is connected to the disk 9 
of the cylindrical member 8. The hydraulic cylinder 14 is also connected 
with a hydraulic pump (not shown) to supply hydraulic pressure. 
Therefore, the hydraulic cylinder 14 can be actuated to move the 
cylindrical member 8 and the shaft 5 either to an ink forming roller 3 
supporting position, as indicated by solid lines in FIG. 3, in which the 
engaging portion 13 is engaged by the tapered portion 7, or, to an ink 
forming roller 3 replacement position, indicated by double broken lines in 
FIG. 3, in which the tapered portion 7 is withdrawn from the engaging 
portion 13. 
A safety device 4 is provided to prevent the ink forming roller 3 from 
falling down. As shown in FIG. 1, a bracket 16 is mounted on the outer 
periphery of one end of the sleeve 10. A through hole 17 extends through 
the bracket 16 and through the bearing 10. A recess 18 is formed at the 
outer periphery of the cylindrical member 8, at a position corresponding 
to the through hole 17. A locking pin 19 is slidably supported in the 
through hole 17, and is urged by a spring 20 in a direction to engage 
within the recess 18 of the cylindrical member 8. 
The rear end of an operation lever 21 is rotatably supported on the bracket 
16, and on the front end of the operation lever 21 is mounted a latch 22. 
The operation lever 21 is slidably connected to the locking pin 19 by a 
pin and slot connection. Therefore, by turning the operation lever 21 in 
the direction of the arrow in FIG. 1, the locking pin 19 can be moved in 
the arrow direction to remove the front end from the recess 18 of the 
cylindrical member 8, and, the latch 22 can then be turned for its free 
end to contact against the outer periphery of the cylindrical member 8, as 
indicated by broken lines in the Figure. 
One end of the cylindrical member 8 is formed with an inclined surface 23 
to guide the locking pin 19 to the recess 18 when the ink forming roller 3 
is mounted. 
An ink forming roller 3 is mounted, by moving the cylindrical member 8 with 
the moving shaft 5 to the position shown in FIG. 1, i.e., in the leftwards 
direction, during which time the protruding locking pin 19 is pushed by 
the inclined surface 23 to move upwards in FIG. 1 against the urging force 
of the spring 20. Further leftwards movement of the cylindrical member 8 
then causes the locking pin 19 to engage within the recess 18. 
As shown in FIG. 1 and 3, the locking pin 19 is then urged by the spring 20 
to engage within the recess 18 of the cylindrical member 8 and the moving 
shaft 5 and its supporting cylindrical member 8 are thus locked against 
movement in axial directions, and, the ink forming roller 3 is thus locked 
in a predetermined operating position in which the engaging portion 13 is 
firmly engages within the tapered portion 7. In this case, even when the 
hydraulic pump stops operating due to an external cause, such as a power 
stoppage or the like, the shaft 5 is held by the locking pin 19 against 
movement in the axial direction, and, the ink forming roller 3 remains 
positively held in the said predetermined position. 
When the ink forming roller 3 is to be replaced, first the latch 22 is 
turned to move the locking pin 19 out of engagement with the moving shaft 
5, thus releasing the cylindrical member and the shaft 5 for movement in 
the axial direction. Then, the hydraulic cylinder 14 is actuated to 
release the engaging portion 13 of the moving shaft 5 from the tapered 
portion 7, thus allowing removal of the ink forming roller 3 for 
replacement. 
At this time, since the cylindrical member 8 has moved to the inside the 
bearing 10, the latch 22 has no supporting surface, and the locking pin 19 
is moved to the locked position by the spring 20. 
To mount another ink forming roller 3, that ink forming roller 3 is set in 
the frame, and the hydraulic cylinder 14 is then operated to cause the 
engaging portion 13 of the moving shaft 5 to engage into within the 
tapered portion 7. During this movement, the locking pin 19 is raised by 
the inclined surface 23, and, when the cylindrical member 8 reaches the 
roller supporting position, the locking pin 19 is moved by the spring 20 
to engage within the recess 18 and thus lock the cylindrical member 8 in 
that position. The latch 22 then contacts the cylindrical member 8. 
However, since the spring 20 has pushed down the locking pin 19, the 
operation lever 22 remains in the state indicated by solid lines in FIG. 
1. 
Thus, a safety device 4 having a locking pin 19 is provided in addition to 
the hydraulic cylinder 14, thereby preventing the ink forming roller 3 
from falling down in the event of a power stoppage or the like. 
Furthermore, since the locking pin 19 is always urged by the spring 20 in 
the engaging direction, when the moving shaft 5 is moved to mount the ink 
forming roller 3, the locking pin 19 automatically engages with the recess 
18 to lock the ink forming roller in place.