Joints and connections – With adjunctive protector – broken parts retainer – repair,...
Reexamination Certificate
1998-10-20
2001-01-23
Browne, Lynne H. (Department: 3629)
Joints and connections
With adjunctive protector, broken parts retainer, repair,...
C403S013000, C403S315000, C403S329000, C101S415100, C101S383000
Reexamination Certificate
active
06176634
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a machine plate fastening means for simply mounting a machine plate in an offset press and, more particularly, to a machine plate fastening means that can be attached in a condition that it is gripped by a plate lock-up device originally installed in a conventional offset press and does not require the offset press to undergo any new processing at the time of attaching.
BACKGROUND OF THE INVENTION
As a press plate for offset printing, not only a presensitized plate using an aluminum plate as a substrate (hereinafter referred to as “a PS plate”) but also a paper plate using a paper substrate and a film plate using a plastic film as a substrate have been prevailingly used. In particular, the use of a low-priced paper or film plate has markedly increased in frequency because of a recent tendency to diversify the purpose of printing and require a small number of copies in printing. Under these circumstances, reduction in time required for replacement work of machine plates has become a great problem.
For instance, in a case where the printing of a small number of copies, such as 300 copies, was performed in the past, the time taken from the start to the finish of printing was about 5 minutes, while the replacement work of machine plates took at least 5 minutes. In other words, it occurred in some cases that the time for attaching a machine plate was longer than a net printing time. Therefore, many devices which enable reduction in working time for replacement of machine plates have been proposed in recent years. For instance, such devices are disclosed in Tokkai Sho 59-1262, Tokkai Hei 3-93546, Tokkai Hei 6-328669, Tokkai Hei 8-39779 (The term “Tokkai” as used herein means an “unexamined published Japanese patent application”), Jikkai Hei 3-19037, Jikkai Hei 3-45133, Jikkai Hei 3-45134 (The term “Jikkai” as used herein means an “unexamined published Japanese utility model application”), and Jikko Hei 6-11782 (The term “Jikko” as used herein means an “examined Japanese utility model publication”).
Each of those devices requires a plate cylinder or/and a plate lock-up device to undergo certain direct processing. However, it is difficult to perform accurate processing at the job site. In attaching such a device to a printing machine which has already been in operation, therefore, it is necessary to detach the parts to be worked from the printing machine and process them with a NC machine in order to secure printing accuracy; as a result, the operations at the job site increases in complexity.
SUMMARY OF THE INVENTION
Therefore, a first object of the present invention is to provide a machine plate fastening means that can be fixed in an offset printing machine at the job site without requiring the printing machine to undergo any processing and enables a paper or film machine plate to be easily attached to and detached from a press cylinder.
A second object of the present invention is to provide a joint plate which can be attached to the aforesaid fastening means when it is required for fixing the fastening means in an offset printing machine at an angle properly adjusted depending on the printing machine.
The above-described objects are attained with a machine plate fastening means for an offset press: which is attached to the offset press in a condition that one end of the means is gripped by a plate lock-up device fitted in the cut-off part of a plate cylinder for the offset printing, and comprises (i) a lower plate having the back part to be gripped by the plate lock-up device, the middle part over which a machine plate is fastened by putting fastening pins in fastening holes punched therein and the front part for introducing the insertion of the machine plate, (ii) a leaf spring for pressing a machine plate inserted and fastened by the fastening pins at the fastening holes which has a bent form and a hole or holes corresponding to the fastening pin or pins and enabling the fastening pin head to go therethrough, and (iii) an upper plate laid on the lower plate and united in the back part of the lower plate; wherein, when the upper plate is arranged only on the back part of the lower plate, the fastening pins are fixed to the middle part of the lower plate so as to project into the space above the lower plate and the leaf spring is held between the upper plate and the lower plate, or when the upper plate is bent into a step and the front part thereof extends over the middle part of the lower plate so as to form a space for fastening the machine plate inserted, the fastening pins are fixed to the middle part of the lower plate or the front part of the upper plate so as to project into the space between the upper plate and the lower plate: and with a joint plate bent in a deformed S-shape which is fixed to the aforesaid fastening means when it is required for attaching to the plate cylinder at a proper angle.
The machine plate fastening means according to the present invention has a great advantage in that no processing is required for an offset press at the time of attaching the fastening means to the offset press. In a special case where a machine plate fastening means is designed so as to have a length slightly shorter than the length of a plate lock-up device originally installed in an offset press, the fastening pins can be fitted in the intended positions with ease and with high accuracy by the use of a NC processing machine; as a result, the present machine plate fastening means can sufficiently answer strict requirements for the registration of machine plates in color printing. Moreover, in accordance with the embodiments of the present invention, the machine plate fastening means can be attached to any types of offset press, so the efficiency in replacement work of machine plates can be significantly heightened.
REFERENCES:
patent: 1379936 (1921-05-01), Quiggan
patent: 2507279 (1950-05-01), Smulski
patent: 3626848 (1971-12-01), Tafel et al.
patent: 5375520 (1994-12-01), Kobler et al.
patent: 5526746 (1996-06-01), Capdeboscq
patent: 5715752 (1998-02-01), Rother et al.
patent: 0 387 397 (1990-10-01), None
patent: 0 872 343 (1998-09-01), None
Patent Abstracts of Japan, Publication No. 03093546, Apr. 18, 1991, all dates 1900.
Patent Abstracts of Japan, Publication No. 08039779, Feb. 13, 1996, all dates 1900.
Browne Lynne H.
Cottingham John R.
Hirakawa Kogyo Sha Co., Ltd.
Millen White Zelano & Branigan
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