Machine for pull-on and pull-out of dampener cover of offset printing press

A machine used for operations of pull-on and pull-out of a water dampener cover to and from the rubber roller of an offset printing press includes a roller holding apparatus for firmly holding the rubber roller constituting a main part of dampening roller or the used dampening roller with a water dampener cover fitted over the surface of the rubber roller and a cover pulling apparatus for pulling the water dampener cover fitted onto the one end of the rubber roller or the water dampener cover fitted over the whole surface of the water dampening roller in the axial direction of the rubber roller while grasping the one end of the water dampener cover to fit the cover over the rubber roller or remove the former from the latter.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a machine usable for operations of pull-on 
and pull-out of a dampener cover to and from the rubber roller of offset 
printing press and more particularly to a machine used for fitting a water 
feed cover over the rubber roller constituting a main part of dampening 
roller adapted to feed water to the printing surface of a printing drum in 
the offset printing press and removing the used cover from the rubber 
roller to replace it with new one. 
2. Description of the Prior Art 
As is well known in the art of offset printing, water is fed to the 
printing surface of a printing drum by using dampening roller and 
thereafter oil based ink is fed thereto by means of a rubber roller which 
serves to feed printing ink. 
The water dampener roller is constructed by fitting a cover having a nature 
of good water absorption over the whole surface of the rubber roller. The 
cover is usually made of knit material in the cylindrical configuration 
and binding strings are provided at both the open ends of the cover. 
When a cover is to be fitted over the surface of a rubber roller, the one 
open end of the cover is previously closed by tightening the binding 
string but the other open end is kept opened with an operator's hands. 
Thereafter, the cover is fitted onto the upper end of a rubber roller 
standing upright on the floor by handling with both the hands of an 
operator, it is then drawn downwardly and finally the other open end of 
the cover which has reached the lower end of the rubber roller is bound 
about the roller shaft by tightening the binding string. Thus, a cover 
fitting operation is achieved. 
However, due to the remarkable progress of printing technology in the 
recent years there has been raised a requirement for more tight fitting of 
a cover over the whole surface of the rubber roller. To satisfactorily 
meet the requirement measures are taken such that the cover is 
strengthened and moreover it is modified so as to exhibit a nature of 
highly increased contractibility when it gets wetted with water. However, 
it takes a long time and a large amount of manpower that the thus improved 
and strengthened cover is manually fitted over the whole surface of the 
rubber roller in the same manner as in the case of the conventional 
dampening roller. Therefore, it becomes hard work. When the used cover is 
replaced with a new one, a cutter is usually used to tear the cover which 
is tightly fitted to the whole surface of the rubber roller but there is a 
danger of damaging the rubber roller or injuring an operator. 
SUMMARY OF THE INVENTION 
Thus, the present invention has been made with the foregoing background in 
mind and its object resides in providing a machine used for operations of 
pull-on and pull-out of a water dampener cover to and from the rubber 
roller of an offset printing press which assures that the cover is easily 
and reliably fitted over the whole surface of the rubber roller and, 
moreover, replacement of an used cover with new one is easily achieved 
without any necessity for a cutter or the like means merely by drawing it 
in the direction away from the roller. 
It is another object of the present invention to provide a machine used for 
operations of pull-on and pull-out of a water dampener cover to and from 
the rubber roller of an offset printing machine which can be easily 
handled by an operator's hand. 
It is another object of the present invention to provide a machine used for 
operations of pull-on and pull-out of a water dampener cover to and from 
the rubber roller of an offset printing machine which can be handle by 
means of a hydraulically operated device such as a hydraulic cylinder or 
the like. 
To accomplish the above objects there is proposed according to the present 
invention a machine used for operations of pull-on and pull-out of a water 
dampener cover to and from the rubber roller of offset printing press 
which essentially comprises a roller holding apparatus for firmly holding 
the rubber roller (constituting a main part of the dampening roller or the 
used dampening roller with a water dampener cover fitted over the whole 
surface of the rubber roller) in the substantially horizontal posture and 
a cover pulling apparatus for pulling the water dampener cover fitted onto 
the one end of the rubber roller or the water dampener cover fitted over 
the whole surface of the dampening roller in the axial direction of the 
rubber roller while grasping the one end of the water dampener cover to 
fit the cover over the rubber roller or to remove the former from the 
latter. 
Other objects, features and advantages of the invention will become more 
clearly apparent from a reading of the following description which has 
been prepared in conjunction with the accompanying drawings.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now, the present invention will be described in a greater detail hereunder 
with reference to the accompanying drawings which illustrate preferred 
embodiments thereof. 
First, description will be made below as to a machine in accordance with 
the first embodiment of the invention with reference to FIGS. 1 to 4. In 
the drawings reference numeral 10 designates a rubber roller constituting 
a main part of dampening roller. The rubber roller 10 includes roller 
shafts 11 at its both ends. Further, reference numeral 20 designates a 
water dampener cover which is formed to the cylindrical configuration to 
fit the dampening roller. Specifically, the water dampener cover 20 is 
made of knit material having a heavy thickness in the cylindrical 
configuration and has the nature of good water absorption. To firmly fix 
both the open ends of the cover 20 onto the roller shafts 11 strings 21 
(one of which is not shown in the drawings) are provided at both the open 
ends of the cover. 
Reference numeral 40 designates a lefthand roller holding section as seen 
in the drawings. The roller holding section 40 is constructed such that a 
roller support shaft 44 with a roller shaft insert hole 43 formed at the 
right end thereof is slidably supported in the horizontal posture in a 
bush 42 mounted on the top of a stand 41 at the left end of a base plate 
30 and the roller support shaft 44 can be immovably held in the bush 42 by 
means of a fitting pin 45. Reference numeral 50 designates a right-hand 
roller holding section. Specifically, the roller holding section 50 is 
constructed in the substantially same manner as the lefthand roller 
holding section 40 such that a roller support shaft 54 with a roller shaft 
insert hole 53 formed at the left end thereof is slidably supported in the 
horizontal posture in a bush 52 mounted on the top of a stand 51 at the 
right end of the base plate 30 and the roller support shaft 54 can be 
immovably held in the bush 52 by means of a fixing pin 55. Thus, a roller 
holding apparatus is constituted by a combination of the left-hand roller 
holding section 40 and the righthand roller holding section 50. 
Reference numeral 60 designates grasping means for grasping the open end of 
the cover 20 around its inner and outer periphery. The grasping means 60 
essentially comprises an the inner ring 61 of which inner diameter is 
determined to be larger than the outer diameter of the rubber roller 10 
and an outer ring 62 adapted to be fitted onto the inner ring 61, as will 
be best seen in FIG. 3. The inner ring 61 is provided with a pair of hooks 
63 at its lefthand end face as seen in the drawing which are adapted to 
come in operative engagement to eyelets 65 at the righthand ends of 
pulling ropes 64. As will be apparent from FIGS. 1 and 2, the ropes 64 are 
horizontally extended to V-shaped pulleys 66 which are mounted on a rotary 
shaft 68 which is bridged between an opposing pair of bearing stands 67 
located in the proximity of the left end of the base plate 30 so that they 
are wound about V-shaped pulleys 66. Further, the other ends of the ropes 
64 are fixed to a winding drum 78 mounted on a shaft 77 which is bridged 
between an opposing pair of channel-shaped bearing stands 74 and 76 
located at the substantially middle part of the base plate 30. The one 
channel-shaped bearing stand 74 is provided with a worm wheel 73 on the 
winding shaft 77 so that the worm wheel 73 meshes with a worm 70 mounted 
on the rotary shaft 71 which is bridged between both the side walls 75 of 
the channel-shaped bearing stand 74 at its upper end. As is apparent from 
FIG. 4, a handle 72 is attached to the one end of the rotary shaft 71. 
Thus, a manual winding section 80 is constituted by a combination of worm 
70 with handle 72 attached thereto, worm wheel 73, winding shaft 77 and 
winding drum 78 which are arranged in that way and, moreover, a manual 
cover pulling apparatus is constituted by a combination of pulling ropes 
64, V-shaped pulleys 66 and manual winding section 80. 
Next, the operations of the machine in accordance with the first embodiment 
of the invention will be described below. 
First, the inner ring 61 is fitted onto the rubber roller 10 and the cover 
20 is fitted onto one of the roller shafts 11. The rubber roller 10 is 
then fixedly held by both the roller holding section 40 and 50 so that the 
cover 20 is oriented toward the righthand roller holding section 50. Then, 
the right end of the cover 20 is firmly bound about the roller shaft 11 
located at the righthand roller holding section 50 by using the string 21, 
while the other open end of the same is fitted with the inner ring 61 
around the inner periphery thereof. Thereafter, the open end of the cover 
20 with the inner ring 61 fitted thereto is tightened with the outer ring 
62 from the outside whereby the open end of the same is grasped by the 
grasping means 60. Next, the hooks 63 on the grasping means 60 are engaged 
to the eyelets 65 of the ropes 64. After completion of engagement of the 
ropes 65 to the grasping means 60 the handle 72 is gradually rotated by an 
operator's hand so that the ropes 64 are wound around the winding drum 78 
via the manual winding section 80. Thus, the cover 20 is ready to be 
pulled in the direction as identified by an arrow mark a. When it is 
confirmed that the rubber roller 10 is fully covered with the cover 20, an 
operator stops rotation of the handle 72, removes the grasping means 60 
from the cover 20 and binds the open end of the cover 20 about the roller 
shaft 11 by using string which is provided around the open end of the 
cover 20 whereby a required dampening roller is built. Finally, the thus 
built dampening roller is disconnected from the roller holding apparatus 
and thereby the roller fitting operation is completed. 
When the used cover is removed from the dampening roller to replace it with 
a new one after a certain period of running time elapses, the removing 
operation is achieved by way of the steps as described below. 
First, the inner ring 61 is fitted into the used dampening roller and the 
assembly of dampening roller and inner ring is then fixedly supported by 
means of both the roller holding sections 40 and 50 which constitute the 
roller holding apparatus. Next, binding strings at both the ends of the 
cover 20 are loosened and the grasping means 60 is attached to the open 
end of the cover 20 located in the area of the lefthand roller holding 
section 40. The eyelets 65 at the one end of ropes 64 are engaged to the 
hooks 63 on grasping means 60 and thereafter the operator gradually 
rotates the handle 72 with his hand whereby the cover 20 tightly fitted 
over the rubber roller 10 is drawn. When the cover 20 is completely 
removed from the rubber roller 10, he stops rotation of the handle 72 and 
the rubber roller 10 is then removed from the roller holding apparatus 
whereby the cover removing operation is finished. 
As will be readily apparent from the above description, the machine 
according to the first embodiment of the invention has an advantageous 
feature that a cover having a high intensity of contractive force can be 
very easily fitted merely by manually rotating the handle while the roller 
is fixedly supported with the aid of the roller holding apparatus. Another 
advantageous feature of the machine is that a used cover tightly fitted 
over the roller can be easily removed therefrom by way of the steps of 
loosening binding strings at both the ends of the roller and repeating the 
above-described operations. Thus, there is no necessity for the tearing of 
the used cover by means of a cutter or the like tool as is often seen with 
the conventional machine and, therefore, the removing operation is safely 
achieved without a fear of causing damage on the rubber roller or injuring 
an operator. 
Next, description will be made below as to the machine in accordance with 
the second embodiment of the invention with reference to FIGS. 5 and 6. In 
the drawings reference numeral 10 designate a roller, reference numeral 11 
designates a roller shaft, reference numeral 20 designates a cover and 
reference numeral 21 designates a string in the same way as in the 
foregoing embodiment. 
Further, reference numeral 140 designates a lefthand roller holding 
section. Specifically, the lefthand roller holding section 140 is 
constructed such that a main cylinder 141 includes a main piston 142 with 
a roller shaft insert hole 143 formed at its foremost end. Reference 
numeral 150 designates a righthand roller holding section. The righthand 
roller holding section 150 is constructed such that a bush 152 adapted to 
receive the roller shaft 11 therein is carried on the top of a stand 151 
at the right end of a base plate 130. Thus, a roller holding apparatus is 
constituted by a combination of the lefthand roller holding section 140 
and the righthand roller holding section 150. 
As will be apparent from FIG. 5, the main cylinder 141 is fixedly mounted 
on the upper surfaces of main cylinder supporting members 144 which are 
slidably supported along cylinder guide rods 146 which are extended in 
parallel with one another in the horizontal posture between both stands 
145, one of them being located at the left end of the base plate 130 and 
the other one being located at the position in proximity of the right end 
of the same. Further, each of the main cylinder supporting members 144 has 
an openable nut 147 fixedly secured to the bottom thereof, the openable 
nut 147 being threadably engaged to a screw rod 148 which is located below 
the cylinder guide rods 146 while extending in the horizontal direction 
between both the stands 145. When the nuts 147 are opened, the main 
cylinder supporting members 14 are free to move, whereas when the nuts 147 
are closed, they are threadably engaged to the screw rod 148 and therefore 
the cylinder supporting members 144 are immovably held by the latter. 
Reference numeral 149 designates a hydraulic passage. 
In the drawings reference numeral 160 designates grasping means for 
grasping the open end of the cover 20. Specifically, the grasping means 
160 essentially comprises a flanged inner pipe 161 having an inner 
diameter larger than the outer diameter of the rubber roller 10, the 
flanged inner pipe 161 being adapted to be fitted into the inner 
peripheral edge at the open end of the cover 20, and sub-pistons 164 with 
grasping pieces 164' attached thereto at the foremost end which are 
adapted to abut against both the sides of the flanged inner pipe 161 by 
actuating sub-cylinders 163. The sub-cylinders 163 are fixedly secured to 
the upper surface of a sub-cylinder supporting member 165 which is 
slidably supported on the cylinder guide rods 146. An openable nut 166 
adapted to be threadably engaged to the screw rod 148 is attached to the 
lower surface of the sub-cylinder supporting member 165 at its center. 
When the nut 166 is opened, the sub-cylinder supporting member 165 is free 
to move, whereas when the nut 166 is closed, the sub-cylinder supporting 
member 165 is threadably engaged to the screw rod 148 and therefore the 
sub-cylinder supporting member 165 is immovably held by the latter. 
Reference numeral 167 designates a pair of pulling rods with hooks 168 
attached to their foremost end which are engaged to the flange 162 of the 
flanged inner pipe 161. The pulling rods 167 are fixedly secured to the 
upper surface of the main cylinder supporting member 144 on both the sides 
of the main cylinder 141. Thus, an automatic cover pulling apparatus is 
consisting mainly of a combination of main cylinder 141, main piston 142, 
main cylinder holding members 144 and pulling rods 167. In the drawings 
reference numeral 169 designates a hydraulic passage on each of the 
sub-cylinders 163. 
Next, operations of the machine according to the second embodiment of the 
invention will be described below. 
First, the flanged inner pipe 161 is fitted onto the rubber roller 10 and 
the cover 20 is fitted onto the one roller shaft. Next, the cover 20 is 
oriented toward the righthand roller holding section 150 and the rubber 
roller 10 is fixedly supported by means of the roller holding sections 140 
and 150 which constitute the roller holding apparatus. The right end of 
the cover 20 is bound about the roller shaft 11 located in the area of the 
righthand roller holding section 150 by using string 21 and the flanged 
inner pipe 161 is inserted into the inner periphery around the left open 
end of the cover 20. Thereafter, the sub-cylinders 163 are actuated until 
the grasping pieces 164' of the sub-pistons 164 come in abutment against 
the flanged inner pipe 161 whereby the open end of the cover 20 is grasped 
by means of the grasping means 160. Next, the hooks 168 at the right ends 
of the pulling rods 167 are operatively engaged to the flange 162 of the 
flanged inner pipe 161. When the thus assembled main cylinder 141 is 
actuated so as to allow the main piston 142 to be displaced outwardly, the 
roller shaft 11 is thrusted with the main piston 142. However, due to the 
fact that the latter is held immovably, the main cylinder 141 is caused to 
move in the leftward direction. As the main cylinder 141 is displaced in 
the leftward direction, the main cylinder supporting member 144, the 
pulling rods 167 and the grasping means 160 are displaced also in the 
leftward direction and thereby the cover 20 is pulled in the direction as 
identified by an arrow mark b. When it is confirmed that the rubber roller 
10 is fully covered with the cover 20, actuation of the main cylinder 141 
is stopped and the openable nuts 147 are closed whereby the main cylinder 
supporting members 144 are threadably engaged to the screw rod 148 and the 
sub-pistons 164 are retracted. Thus, the flanged inner pipe 161 can be 
removed from the cover 20. Thereafter, the open end of the cover 20 is 
bound about the roller shaft 11 by using string. As a result, a dampening 
roller is built. Finally, thus built dampening roller is removed from the 
roller holding apparatus and thereby the cover fitting operation is 
finished. 
The removing operation of a used cover is achieved by way of the steps as 
described below so as to replace it with new one. 
Prior to removing of the used cover from the dampening roller, the flanged 
inner pipe 161 is fitted onto the dampening roller and the latter is then 
immovably held by means of both the roller holding sections 140 and 150. 
Next, binding strings at both the ends of the cover 20 are loosened and 
the open end of the cover 20 located in the area of the lefthand roller 
holding section 140 is grasped with the aid of the grasping means 160. 
After the hooks 168 of the pulling rods 167 are engaged to the flange 162 
of the flanged inner pipe 161, the main cylinder 141 is actuated in the 
leftward direction and thereby the cover 20 tightly fitted over the rubber 
roller 10 is pulled. When the cover 20 is fully removed from the rubber 
roller 10, actuation of the main cylinder 141 is stopped and thereafter 
the rubber roller 10 is displaced from the roller holding aparatus. Thus, 
the cover removing operation is finished. 
As will be readily understood from the above description, the machine in 
accordance with the second embodiment of the invention has an advantageous 
feature that a cover having high intensity of contractive force can be 
very easily fitted merely by simple operations comprising the steps of 
immovably holding the rubber roller on the roller holding apparatus and 
displacing the main cylinder. Further, another advantageous feature of the 
machine is that replacement of a used cover with a new one is achieved 
simply and safely by way of the steps of loosening binding strings at both 
of the ends of the dampening roller and then repeating operations as 
described above to remove from the roller the cover which is tightly 
fitted over the latter. 
While the present invention has been described above with respect to two 
preferred embodiments, it should of course be understood that it should 
not be limited only to them but various changes or modifications may be 
made in any acceptable manner without departure from the spirit and scope 
of the invention as defined by the appended claims.