US3897292A - Method of producing a printing magnetic saddle - Google Patents

Abstract

A magnetic saddle for use in printing comprising the base plate for saddle consisting of a non-magnetic material and superposed on the printing cylinder, a plurality of yokes arranged at regular intervals on the surface of said base plate lengthwise, and the permanent magnet consisting of a plurality of small blocks of ferromagnetic material, said blocks being arranged between said yokes and conjoined by virtue of the binder consisting of a thermosetting resin and filling the gaps, wherein the base plate, the yoke and the permanent magnet are integrated.

Description

[ July 29, 1975 3,350,030 10/1967 Green 156/173 3,568,286 3/1971 Ross.......... 156/169 3,635,775 1/1972 Wesch......... 156/173 3,670,646 6/1972 Welch, Jr. 101/382 MV 3,733,233 5/1973 156/173 Primary ExaminerDaniel J. Fritsch Attorney, Agent, or FirmWoodhams, Blanchard and Flynn [57] ABSTRACT A magnetic saddle for use in printing comprising the base plate for saddle consisting of a non-magnetic material and superposed on the printing cylinder, a plurality of yokes arranged at regular intervals on the surface of said base plate lengthwise, and the permanent magnet consisting of a plurality of small blocks of ferromagnetic material, said blocks being arranged between said yokes and conjoined by virtue of the binder consisting of a thermosetting resin and filling the gaps, wherein the base plate, the yoke and the permanent magnet are integrated.

4 Claims, 9 Drawing Figures 264/263 B32B 1/10; B32B 5/12; B65H 81/08 MAGNETIC SADDLE Inventor: Yasuo Fukuyama, Osaka, Japan Assignee: Yamauchi Rubber Industry Co., Ltd., Hirakata Japan June 4, 1973 Appl. No.: 366,722

Related U.S. Application Data [62] Division of Ser. No. 281,642, Aug. 18, 1972, Pat. No.

264/257; 264/261' Int. CL Field of Search 156/153, 154, 169, 172, 156/173, 174, 245, 425, 426, 443, 250; 101/382 MV; 264/162, 159, 241

References Cited UNITED STATES PATENTS 8/1967 Nutt et United States Patent Fukuyama METHOD OF PRODUCING A PRINTING [22] Filed:

PATENTEDJUL29IH75 1891292 SHEET 1 FIG. 3

PATENTEI] JUL 2 9 I975 SHEET FIG?- FIG. 5

FIG.

METHOD OF PRODUCING A PRINTING MAGNETIC SADDLE This is a division of application Ser. No. 281,642, filed Aug. 18, 1972, now US. Pat. No. 3,824,926.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic saddle to be mounted on the printing cylinder of a printing machine and a method of producing the same.

2. Description of the Prior Art The fitting of a saddle of this type on the printing plate has heretofore been performed by the use of an adhesive tape. Such means of fitting, however, is defective in that it takes too much time not only in fixation of the printing plate, amendment of the position thereof, and so on, but also in removal of the adhering adhesive tape per se and clearing off the adhering remnants after the demounting of said printing plate.

With a view to making up for these defects, a variety of magnetic saddles designed to make the printing plate magnetically fit thereon have already been proposed.

However, such a magnetic saddle as being satisfactory in strength, stiffness and magnetic force concurrently has never been proposed.

In the case of a magnetic saddle composed of sinterred ferrite magnets, for instance, though it admittedly possesses sufficient strength and stiffness, it is defective in that, because of its poor impact resistance, it is apt to be damaged or its edge chipped when dropped by mistake, and, not only that, its production cost becomes too high as it requires a large-sized press.

As to a magnetic saddle composed of a mixture of ferrite and synthetic rubber, synthetic resin or the like, it is defective in that it is difficult not only to produce such one as having a magnetic force of required strength but also to realize and maintain the dimensional accuracy thereof.

In the case of a magnetic saddle wherein an electromagnet is laid, it is also defective in that it tends to be complicated in structure per se, requires troublesome wiring to supply electricity to the electro-magnet, and calls for special consideration in respect of the safety device to ward off danger involved in the application of electricity.

SUMMARY OF THE INVENTION The principal object of the present invention is to provide a printing magnetic saddle which makes up for the aforementioned defects of the conventional magnetic saddles and is possessed of less thickness, more strength and stiffness, and a very strong magnetic force, as compared with the latter.

Another object of the present invention is to provide a printing magnetic saddle which makes it possible not only to fix the printing plate magnetically on the saddle by merely placing the former on the latter, but also to perform amendment of the position of the printing plate easily as compared with the conventional saddles.

A further object of the present invention is to provide a printing magnetic saddle which has a base consisting of a non-magnetic material, said base plate being so devised that the magnetic line of force emanating from the permanent magnet disposed on its outside leaks to the side of the printing cylinder to thereby prevent the flux density on the surface of the saddle from decreasing and generate a strong magnetic force on said surface.

A still further object of the present invention is to provide a printing magnetic saddle, wherein the base plate consisting of a non-magnetic material is composed of a wound fibrous layer impregnated with a thermosetting resin, said base plate combined with the yoke and the permanent magnet being molded into a whole and imparted with flexibility and elasticity.

Still another object of the present invention is to provide a printing magnetic saddle, wherein the yokes and the small block-shaped magnets are arranged on the base plate consisting of a non-magnetic material along the circumferential direction to maintain the stiffness, and said yokes and magnetic are made to adhere firmly and integrally by means of a thermosetting resin on the base plate composed of a fibrous layer impregnated with a thermosetting resin, so that it is free of deformation by the frictional heat arising at the time of use and is possessed of a hardness and mechanical properties enough to cope effectively with the printing pressure.

An additional object of the present invention is to provide a printing magnetic saddle, wherein a coating film of rubber or high molecular substance having a large coefficient of friction is formed on its surface, whereby the printing plate put thereon is prevented from sliding, the surface of the permanent magnet is free from damage, and the yoke is prevented from getting rusty.

Yet another object of the present invention is to provide a printing magnetic saddle, wherein said wound fibrous layer forming the non-magnetic base plate consists of a plurality of inner layers, each inner layer being composed of fibers as wound round the iron core in parallel at essentially a right angle to the axial direction of the iron core, and a plurality of outer layers of fibers as wound round the iron core at an oblique angle to the axial direction of the iron core, said outer layers consisting of the layer of fibers as wound at said oblique angle clockwise and the layer of fibers as wound at the same oblique angle but anticlockwise, alternately, and is not only possessed of sufficient flexibility as well as elasticity but also capable of demonstrating an extremely high work accuracy without resorting to delicate internal finishing work.

Still an additional object of the present invention is to provide a printing magnetic saddle, wherein the diameter of the iron core for the purpose of molding a cylindrical material for the saddle is determined to be very slightly smaller than the diameter of the printing cylinder by taking into consideration the fact that said cylindrical material tends to expand outward when split into plural saddles resulting in an enhanced radius of curvature of the saddle, thereby making the saddle fitting for the printing cylinder.

BRIEF DESCRIPTION OF THE DRAWING FIG. 4 is a perspective view of the state of the fibrous layer as wound round the iron core.

FIG. 5 is a plan of the yoke with the blocks of permanent magnet arranged thereon.

FIG. 6 is a cross-sectional view taken along the line VI-VI in FIG. 5.

FIG. 7 is a front view of the longitudinal cross-section of the state of a mold at the time of pouring the thermosetting resin therein.

FIG. 8 is a perspective view of a couple of semicylindrical saddles obtained from one cylindrically molded material.

FIG. 9 is a front view of the longitudinal cross-section of another mold applicable in practicing the pouring of the thermosetting resin.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1, the numeral reference 1 denotes the printing cylinder, 2 denotes the magnetic saddle according to the present invention as mechanically fitted on said printing cylinder, and 3 denotes the printing plate as magnetically fixed on the surface of said magnetic saddle 2.

In FIGS. 2 and 3 showing the essential part of said magnetic saddle 2 on an enlarged scale, the numeral reference 4 denotes the non-magnetic arcuate base plate composed of fibrous layer impregnated with a thermosetting resin, and 5 denotes the yoke having a high magnetic permeability which consists of soft iron, Ni-Mo-Fe alloy, Mn-Zn ferrite, Ni-Zn ferrite, Ni-Zn-Co ferrite and the like and is provided with the blockshaped magnets 6 disposed on the surface of its one side at regular intervals along the circumferential direction. Accordingly, the yokes 5 and the magnets 6 are disposed alternately along the axial length of the base plate 4. On this occasion, the magnets 6 are disposed in such a fashion that the confronting sides of the neighboring magnets 6 along the axial length of the base plate 4 are of the same polarity and repel each other. The top side of the magnet 6 is inside the circumference of the yoke 5, and the gap between the top side of the magnet and the outer circumference of the yoke as well as the gap between the circumferentially spaced magnets are filled with the thermosetting resin 7, whereby these members are firmly conjoined. In FIG. 2, M denotes the magnetic lines of force.

Hereunder will be described the method of producing the foregoing magnetic saddle by reference to FIG. 4 and those that follow.

Referring to FIG. 4, a glass fiber having the glass content of 75 80% and impregnated with a thermosetting resin such as expoxy resin and the like is wound round the iron core 8 which is smaller in diameter than the printing cylinder by 0.2 0.6% in parallel and essentially at right angles to the axial direction of the iron core 8 in the beginning. Subsequently, the same glass fiber is wound round the same iron core 8 in clockwise spiral fashion at an oblique angle to the axial direction of said core to form a layer of spirally wound glass fiber and next in anticlockwise spiral fashion at said oblique angle to the axial direction of said core to form another layer of spirally wound glass fiber. Upon obtaining a fibrous layer of a prescribed thickness by repeatedly forming the foregoing two types of layers of glass fiber wound spirally in the opposite directions alternately (fibers of two adjacent ones of said layers being diagrammatically indicated at 8A and 8B respectively in FIG. 4), said fibrous layer is heated to harden the component resin and then its external surface is subjected to grinding work to be made into the cylindrical member 9 of about 3 mm thick. Thereafter, the cylindrical member 9 is released from the iron core 8.

FIGS. 5 and 6 show the yoke with magnets: that is, the ring-shaped yoke 5 of less than 2 mm thick made of soft iron is provided with a plurality of block-shaped magnets 6 of 5 15 mm thick each as fixed on its one side with an adhesive at regular spaced intervals along the circumferential direction.

FIG. 7 shows a mode of fixing the yoke with magnets on the surface of the aforesaid cylindrical member 9: that is, the cylindrical member 9 is put erect on the base plate 10; after applying adhesive to the surface of the cylindrical member 9, the yoke 5 with magnets is fitted on the cylindrical member 9 by its central hole one after another; when the pile of yokes 5 attain a prescribed height, the cylindrical outer mold 11 having an inside diameter slightly larger than the outside diameter of the yoke 5 is fitted on said pile; a colored thermosetting resin, such as epoxy resin, as mixed with 20 50% of a filler is poured into the thus set outer mold l 1; the resin is hardened by applying heat; and thereafter the outer mold ill and the base plate 10 are removed.

Next, after grinding the external surface of the product to attain the prescribed measurements, by cutting said product with a metal saw and the like as shown in FIG. 8, a plural number of saddles 2 are obtained.

Hereunder will be given an example embodying the present invention by reference to FIG. 9.

EXAMPLE A glass roving (GYR-6O PWE) made by Nitto Bo K.K. as subjected to dipping in an epoxy resin (CIBA GY 250)/acid anhydride (I-IHPA: hexa-hydrophthalic anhydride) was wound around the iron core 8 measuring 325.35 mm (outside diameter) X 500 mm (length) by means of a filament winding machine in such a fashion that first winding the glass roving in parallel at essentially a right angle to the axial direction of the iron core 8 to form 2 3 layers consisting of said glass roving, thereafter winding clockwise in parallel at an oblique angle to said axial direction to form a layer of said glass roving on the foregoing layers, next winding anticlockwise in parallel at the same oblique angle to form another layer of the glass roving, and repeatedly forming the above two types of layer of glass roving wound spirally in the opposite directions alternately, whereby the cylindrical member 9 composed of wound multilayers of glass roving was formed. After hardening this cylindrical member 9 by heating at C for 3 hours, its surface was subjected to grinding to attain the diameter of 331 mm.

Subsequently, said cylindrical member 9 was put erect on the base plate 12, the washer 13 was fitted on the cylindrical member 9, the anisotropic sinterred ferrite blocks 6 measuring 7 mm (t) X 4 mm (w) X 20 mm (1) each (See FIGS. 5 and 6) were arranged on the surface of said washer 13 along the circumferential direction, the yokes 5 made of soft iron and measuring 350 mm (outside diameter) X 332 mm (inside diameter) X 1 mm (thickness) each were put on said ferrite blocks by fitting on the cylindrical member 9, said ferrite blocks 6 arranged as above and the yokes 5 being piled up alternately to attain 400 mrn in height, and the washer 14 was put on the top of the pile. On this occasion, the yoke 5, the ferrite blocks 6 and the cylindrical member 9 were conjoined with an epoxy adhesive (ClBA GY-252/A-l55/l-l4) at the room temperature.

Next, the cylindrical outer mold having the inside diameter slightly larger than the outside diameter of the yoke 5 was fitted to the exterior of the structure built as above, and then a liquid epoxy resin (ClBA GY-252) mixed with a coloring agent and a filler was poured into it from its top so as to fill all the gaps, hardened at the room temperature, and thereafter completely hardened by 12 hours after-cure at 60C.

Subsequent to the curing, after removing the base plate 12 and the outer mold 15, the structure was subjected to grinding to attain 346.l3 i- 0.02 mm in outside diameter, then cut into a couple of semicylindrical segments with a metal saw and the like and released from the iron core, whereby the magnetic saddles of about 10 mm thick for use in printing newspapers were obtained. These saddles were next coated with urethane resin having the static friction coefficient of 0.65 to attain 0.06 mm in thickness.

A magnetic saddle for use in printing newspapers is generally required to be possessed of a thickness accuracy of 2/100 mm and the magnetic flux density of more than 1,000 gauss.

The magnetic saddle produced as above according to the present invention proved to have the thickness accuracy of 1.5/ 100 mm and the magnetic flux density of 1,500 gauss.

What is claimed is:

l. A method of producing a magnetic saddle for use on a printing cylinder in printing, which comprises: winding a fibrous layer impregnated with a thermosetting resin round an iron core for molding purposes; hardening said fibrous layer by heating; grinding the external surface of the hardened fibrous layer to form a non-magnetic cylinder; piling up a plurality of ringshaped yokes having an inside diameter almost equal to the outside diameter of said cylinder by fitting said yokes on the cylinder one after another with a layer of magnets between each pair of yokes wherein said layer of magnets comprises a plurality of small block-shaped magnets circumferentially disposed at regular intervals along the sides of the adjacent pair of yokes; fitting a cylindrical outer mold having the inside diameter slightly larger than the outside diameter of said yoke on the circumference of the pile of yokes; pouring a liquid thermosetting resin into said outer mold so as to fill all the gaps between the magnets and the yokes; hardening the thus filled liquid resin by heating; removing the outer mold; and cutting the molded product along the axial direction into the prescribed number of saddles.

2. A method as defined in claim 1, wherein said iron core for the purpose of molding the non-magnetic cylinder is very slightly smaller in diameter than the printing cylinder whereon the magnetic saddle to be produced is to be mounted for use in printing.

3. A method as defined in claim 1, wherein said step of winding the fibrous layer round said iron core for molding purposes includes winding plural inner layers of fibers round the iron core with the fibers of each layer in parallel at essentially right angles to the axial direction of the iron core and then winding plural outer layers of fibers round the inner layers on the iron core with the fibers thereof at an oblique angle to the axial direction of the iron core, wherein the fibers of alternate ones of said outer layers are wound at said oblique angle clockwise and the fibers of the other outer layers are wound at the same oblique angle but anticlockwise.

4. A method as defined in claim 1 including, between said grinding and piling steps, the further step of placing said cylinder erect on a base plate; and, after said step of hardening the filled resin, removing said base plate.

Claims (4)

1. A METHOD OF PRODUCING A MAGNETIC SADDLE FOR USE ON A PRINTING CYLINDER IN PRINTING, WHICH COMPRISES: WINDING A FIBROUS LAYER IMPREGNATED WITH A THERMOSETTING RESIN ROUND AN IRON CORE FOR MOLDING PURPOSSE, HARDENING SAID FIBROUS LAYER BY HEATING, GRINDING THE EXTERNAL SURFACE OF THE HARDENED FIBROUS LAYER TO FORM A NON-MATNETIC CYLINDER, PILING UP A PLURALITY OF RING-SHAPED YOKES HAVING AN INSIDE DIAMETER ALMOSE EQUAL TO THE OUTSIDE DIAMETER OF SAID CYLINDER BY FITTING SAID YOKES ON THE CYLINDER ONE AFTER ANOTHER WITH A LAYER OF MAGNETS BETWEEN EACH PAIR OF YOKES WHEREIN SAID LAYER OF MAGNETS COMPRISES A PLURALITY OF SMALL BLOCK-SHAPED MAGNETS CIRCUMFERENTIALLY DISPOSED AT REGULAR INTERVALS ALONG THE SIDES OF THE ADJACENT PAIR OF YOKES, FITTING A CYLINDRICAL OUTER MOLD HAVING THE INSIDE DIAMETER SLIGHTLY LARGER THAN THE OUTSIDE DIAMETER OF SAID YOKE ON THE CIRCUMFERENCE OF HE PILE OF YOKES, POURING A LIQUID THERMOSETTING RESIN INTO SAID OUTER MOLD SO AS TO FILL ALL THE GAPS BETWEEN THE MAGNETS AND THE YOKES, HARDENING THE THUS FILLED LIQUID RESIN BY HEATING, REMOVING THE OUTER MOLD, AND CUTTING THE MOLDED PRODUCT ALONG THE AXIAL DIRECTION INTO THE PRESCRIBED NUMBER OF SADDLES.

2. A method as defined in claim 1, wherein said iron core for the purpose of molding the non-magnetic cylinder is very slightly smaller in diameter than the printing cylinder whereon the magnetic saddle to be produced is to be mounted for use in printing.

3. A method as defined in claim 1, wherein said step of winding the fibrous layer round said iron core for molding purposes includes winding plural inner layers of fibers round the iron core with the fibers of each layer in parallel at essentially right angles to the axial direction of the iron core and then winding plural outer layers of fibers round the inner layers on the iron core with the fibers thereof at an oblique angle to the axial direction of the iron core, wherein the fibers of alternate ones of said outer layers are wound at said oblique angle clockwise and the fibers of the other outer layers are wound at the same oblique angle but anti-clockwise.

4. A method as defined in claim 1 including, between said grinding and piling steps, the further step of placing said cylinder erect on a base plate; and, after said step of hardening the filled resin, removing said base plate.

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