US3431843A - Detecting device for a copy sheet clamping device in an offset printing machine - Google Patents

Description

March 11, 1969 TAMAKI KANEKO ETAL 3,431,843 DETECTING DEVICE FOR A COPY SHEET CLAMPING DEVICE IN AN OFFSET PRINTING MACHINE Filed Dec. 28, 1966 Sheet ofs F/G. f ilf \7 INVENTOR M rch 1 .1969 TAMAKI KANEKO ETAL 3,431,343

DETECTING DEVICE FOR A COPY SHEET CLAMPING DEVICE IN AN OFFSET PRINTING MACHINE Filed Dec. 28, 1966 Sheet 2- of5 INVENTOR A rfs Mar h 1969 TAMAKI KANEKO ET-AL 3,431,343

DETECTING DEVICE FOR A COPY SHEET CLAMPING DEVICE v IN AN OFFSET PRINTING MACHINE Filed Dec. 28. 1966 Sheet 3 of :5

I 4? 65 be m 52 I J 9'0- Q' l 5/ l 62; e I I INVENTOR United States Patent O 40/s1,s9s U.s. Cl. 101-218 Int. Cl. 1541f 7/02, 1/30, 21/00 4 Claims ABSTRACT OF THE DISCLOSURE A safety device for a printing machine which separates the blanket and impression cylinders when there is no copy sheet, or copy sheet is improperly positioned on the impression cylinder.

BACKGROUND OF INVENTION This invention relates to a detecting device which indicates whether a copy sheet clamping device in a rotary offset printing machine has correctly operated. A means which indicates whether copy sheets have normally been delivered one sheet at a time towards the direction of an impression cylinder by means of an automatic paper feeding device from a stack of copy sheets piled in the front part of an offset printing machine, or a means which indicates whether a copy sheet has correctly been fed into a copy sheet passage channel extended between a paper feeding device and an impression cylinder, is well-known in the art and is incorporated in some of the conventional offset printing machines. However, such known means merely indicates whether the copy sheet has been delivered in the direction of the impression cylinder, but does not show whether the copy sheet has correctly been caught by a copy sheet clamping device provided on the circumference of the impression cylinder.

A detecting device according to this invention has a function, when activated, to operate a contacting and detaching device for a blanket cylinder and an impression cylinder so that, when a copy sheet is not delivered and caught properly for some reason or other, the blanket cylinder will be removed from the impression cylinder, thus preventing a possible back printing which results from the inked image on the blanket cylinder being transferred onto the impression cylinder when a copy sheet is not delivered and then being retransferred on the back of the following copy sheet.

With the known device having no function of detecting whether the copy sheet was correctly caught by the clamping device, operation of said contacting and detaching device is not altered so long as the copy sheet is delivered by the paper feeding device, irrespective of clamping operation.

Consequently, the blanket cylinder and the impression cylinder continue to rotate in contact with each other even if the copy sheet were not fed thereinbetween, entailing transfer of the inked image onto the circumference of the impression cylinder.

Therefore, it is a primary object of this invention to provide an offset printing machine with an operation detector for a copy sheet clamping device, whereby performance of said clamping device provided on a part of the circumference of the impression cylinder is correctly detected and a back printing phenomenon often caused by the conventional offset printing machine can be completely removed.

Patented Mar. 11, 1969 SUMMARY OF THE INVENTION This invention is characterized in that, in an offset printing machine having a function of pressing and detaching a blanket cylinder and an impression cylinder, the impression cylinder, which carries a copy sheet clamping device on its circumference for clamping the leading edge of a copy sheet fed by a paper feeding device, is provided with a pin movable approximately in a radius direction of said impression cylinder, said pin being so designed as to protrude its outer end to the circumference of said impression cylinder when a copy sheet is not caught by said copy sheet clamping device, said pin activating, by the aforesaid protruding movement, said contacting and detaching device so as to detach said blanket cylinder from a contact condition with said impression cylinder.

FIG. 1 is a left side view of an offset printing machine according to the embodiment of this invention.

FIG. 2 is a sectional view taken on dotted line IIII of FIG. 1.

FIG. 3 is a side view of a paper feeding mechanism used in the above-mentioned printing machine.

FIG. 4 is a side view showing a contacting and detching device for a blanket cylinder and an impression cylinder, with other parts omitted.

FIG. 5 is a sectional view of the main part of a detecting device according to one embodiment of this invention.

FIG. 6 is a slant view showing a detecting member provided on an impression cylinder, with other parts omitted.

FIG. 7 is a sectional view illustrating a part of FIG. 5 in developed scale.

FIG. 8 is a plan View of an impression cylinder.

FIG. 9 through'FIG. 11 respectively show sectional views taken on dotted line )QI-XI of FIG. 8, illustrating various operative positions of a detecting device.

FIG. 12 is a side view of a cam disc which activates a. copy sheet clamping device and a detecting device.

FIG. 13 is a side view corresponding to FIG. 11, illustrating a modified embodiment of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT A full understanding of the nature of this invention will be had by reference to the above described drawings and herein specification.

1 is a left side wall of a rotary offset printing machine. 2 is a plate cylinder on which is rolled an offset plate. 3 is a blanket cylinder on which circumference the inked image is transferable from the plate cylinder. 4 shows an impression cylinder on which said blanket cylinder 3 is pressed at a suitable time. A blanket cylinder shaft 5, on which the blanket cylinder 3 is loosely mounted, is provided at an end face thereof, with an eccentric shaft 5a which is rotatably supported by a bearing fixed on the aforesaid side wall 1.

On said eccentric shaft 5a are provided an operating lever 6 and a correspondingly movable lever 7, said operating lever 6 being rotatably mounted on said eccentrio shaft whereas said movable lever 7 is fixed on the latter. The operating lever 6 and the movable lever 7 are connected by means of a compressing spring 8. A bent portion 6a provided on a (lateral) side edge of said operating lever 6 is pressed against an abutment provided on a side edge of the movable lever 7. The operating lever 6 tends to rotate counterclockwise around said eccentric shaft 5a under the influence of a spring 9 which is fixed, at its one end, to the side wall 1, rotation of said operation lever 6 being limited by the bent portion 6b of said lever striking against a roller 10.

A base portion of the roller 10 is provided on a free end of an oscillating arm 12 which, in turn, is pivoted on the side wall 1 by a shaft 11. On the back of said oscillating arm 12 is provided a roller 14 which is pressed, by the force of a spring not shown, on the circumference of a cam disc 15 fixed on a shaft 4a which rotates integral with the impression cylinder 4. The oscillating arm 12, therefore, is given, by an angular cam 15a of said cam disc 15, an oscillation movement which is imparted to the aforesaid operating lever 6. Over a bent portion 60 extruding from a right lateral edge of the operating lever 6 extends an extreme end of a stopper member 16 which is fixed on a shaft rotatably supported on both side walls of the printing machine. At one end portion of said shaft 17 proximate to a side wall corresponding the side wall 1 is fixed, as shown in FIG. 5, an upper edge 18a of a wire arm 18 which is adapted to rotate counterclockwise by an operation hereinafter described whereby a shoulder portion 16a of the aforesaid stopper member 16 disengages from the bent portion 60 of the operating lever 6.

Referring now to FIG. 1, in an upper right position over that of a shaft 4a of the impression cylinder 4 is provided a bent lever 19 pivoted on the side wall 1 by a shaft 20, said bent lever carrying, at its free end, a roller 43 cooperating with a cam plate 42 fixed on the back of the aforesaid cam disc 15.

At an elbow portion of said bent lever 19 is pivoted one end of a connecting link 21 which is secured, at the other end, on a gear 22. Gear 22 is loosely mounted on shaft 23, secured to side wall 1. Said idler gear 25 meshed with gear 22 ismounted on oscillating plate 24. Said idler gear 25 being meshed with a gear 26 on oscillating plate 24. A shaft 27 of the gear 26 extends, through arcuate slots 28 respectively provided on each side wall of the printing machine, cut of a right side wall 1 (refer to FIG. 3) and is rotatably supported, outside of said side wall 1', by an oscillating plate 29 provided on the aforesaid shaft 23.

The shaft 27 further carries a plurality of friction wheels 30 fixed thereon between side walls 1 and 1. The lower edge of a free end of the aforesaid oscillating plate 29 is provided with a studded screw 31, the lower end of said screw being adapted to be pushed by an upper end of a thrust lever 32, whereby the aforesaid friction wheels 30 comes in contact with, or thrusted apart from, piled copy sheets 33.

The abovementioned thrust lever 32 is movably supported by means of its slot 35 and a headed stud 34 fixed on the outer surface of the side wall 1 and is pivoted, by a shaft 38, at an arm end of a bell crank 37 which is secured on the side wall 1 by a shaft 36. At the other end of said bell crank 37 is fixed a roller 39 which is pressed on a fan-shaped cam 40 by the force of a spring (not shown) acting on said bell crank 37. The fan-shaped cam 40 is fixed, at an outer side of the side wall 1, on a shaft 4a integrated with the impression cylinder 4.

Therefore, the integral rotation of said fan-shaped cam 4a with the impression cylinder 4 provides the oscillating plate 29 with an oscillation movement through the aforesaid bell crank 37 and the thrust lever 32, thereby bringing the friction wheels 30 into contact intermittently with the copy sheets.

Referring to FIG. 1, an irreversible rotation device 41 is provided between the gear 26 and its shaft 27, so that to the shaft 27 is imparted a rotative movement when the gear 26 revolves in the direction of the arrow, while it is retained in a stationary position when said gear 26 revolves in the opposite direction. The aforesaid reciprocating rotation of said gear 26 is provided by a similar movement of a gear 22 driven by the connecting link 21 when the bent lever 19 makes a reciprocating movement by the action of a cam plate 42.

In a position above the oscillating plate 24 is located a lever pivoted on the side wall 1 by a shaft 44. The said lever 45 is urged to rotate in a counterclockwise di rection around its shaft 44 by the force of a contractable spring 46, and retains the aforesaid oscillating plate 24 in a stationary position by engaging, at its shoulder portion 45a, with a bent portion 24a of the latter plate. Said lever 45 is adapted to be moved when the copy sheets start to be fed, by an outer force in the arrow direction, whereupon the said lever is disengaged from the oscillating plate 24. A contractable spring 47 which appears to be pulling up the oscillating plate 24 lacks sufiicient elasticity to do so alone, but rather, it is adapted to suitably control the pressure of the friction wheels 30 when the latter is in contact with the copy sheets. At both end walls 48a and 48b of indentation 48 which is provided on one part of the circumference of the impression cylinder 4 (refer to FIGS. 5, 7 and 8) are loosely supported the ends of a shaft 49 extending in parallel with an impression cylinder shaft 5, said shaft 49 transfixing finger supports 52 which carry conventional copy sheet clamping fingers fixed by studded screws 51. One end 49a of said shaft 49 extending through the aforesaid end wall 48a is fixedly secured with a base portion of a short arm 53 which is connected to said oscillating member 54, with a pin 53a fixed on its free end loosely fitted into a slot 54a of the oscillation member 54. The oscillating member 54, pivoted at an end face of the impression cylinder by a shaft 55, is urged to rotate counterclockwise around said shaft 55 by the force of a spring 56 fixed, at one end thereof, on a portion of the impression cylinder, whereby the fingers 50 are adapted to open, as shown in FIG. 9, when a roller 57 secured on said oscillating member 54 is pressed on a cam 58a, and close, as shown in FIG. 10', when said roller 57 is separated from said cam 58a.

The cam 58a is fixed, by a stud 60, on the inner surface of another cam 59 secured on the inner surface of a side wall 1 (refer to FIG. 8). Said cam 58a is adapted to push out the roller 57 in order to open the fingers 50 when the impression cylinder 4 takes a rotated position as shown in FIG. 9 ready to catch the leading edge 62a of the copy sheet 62 fed in a high speed into the copy sheet passage channel. Subsequently, when the impression cylinder rotates counterclockwise from the position shown in FIG. 9, causing the roller 57 to disengage from the cam 58a as shown in FIG. 10', the fingers 51 are closed so as to clamp the leading edge of the copy sheet 62. The above mentioned roller 57 cooperates with another cam 58b in addition to the cam 58a.

That is to say, the roller 57 is again pushed out by the cam 58b when the impression cylinder 4 is rotate-d counterclockwise from the rotated position shown in FIG. 10, causing previously closed fingers 51 to open and thereby release the leading edge of the copy sheet from the impression cylinder. The copy sheet thus released is delivered to a receiving tray through a suitable guide. The copy sheet clamping device referred to above is wellknown in the art.

On the lateral wall 480 of the indentation 48 (refer to FIG. 7) proximate to the circumference of the impression cylinder is fixed, by a headed screw 65, a feeler pin support 64 carrying as many feeler pins 63a as the clamp fingers 50, said feeler pins 63 being loosely fitted so as to be movable approximately in a radius direction. Said feeler pins 63 are respectively fixed, at its inner ends, to a bar 66. The connecting shafts 67a and 67b, respectively provided on each end of said bar 66, are extended, through slots 68 on both end walls of the indentation 48, and out to both ends of the impression cylinder 4, said slots 68 being elongated in the radius direction (refer to FIG. 7). Both extreme end shafts 67a and 67b of the bar 66 are loosely held by notches 70a and 70b respectively provided on a pair of oscillatable arms 69a and 69b provided on each end face of the impression cylinder 4.

The abovementioned pair of arms 69a and 69b are fixedly secured respectively on each end of a shaft 71 extending through the inside of the impression cylinder 4, one arm 69a carrying a roller 72 which cooperates with the aforesaid cam plate 59 as shown in FIG. 11 On the other hand, the oscillating plate 73, coaxially pivoted with the aforesaid oscillating member 54, is urge-d to rotate in a counterclockwise direction around a shaft 55 by the force of a compressing spring 74 which is fixed, at its one end, on a part of the impression cylinder 4, the rotation of said oscillating plate 73 being limited by a pin 75, fixed thereon, striking against the inner edge of an extreme end of the aforesaid arm 69a. When the impression cylinder 4 is rotated in a counterclockwise direction, the cam plate 59 provides an oscillation movement to the arm 69a which is indirectly being affected by elasticity of the aforesaid spring 74, thereby causing the feeler pins 63 to make a reciprocating movement in a radius direction of the impression cylinder. FIG. 9 shows a mode of operation in which the roller 72 is pushed out by the circumference 59a of the cam 59, causing the outer edge of a feeler pin 63 to take an inner position from the circumference of the impression cylinder 4. FIG. 11 illustrates a mode of operation in which the roller 72 is disengaged from the circumference 59a, causing the outer edge of the feeler pin 63 to protrude from the circumference of the impression cylinder 4. FIG. 11 shows a mode of operation in which the above mentioned protruding movement of the outer end of the feeler pin 63 is obstructed by the copy sheet despite the roller 72 is disengaged from the circumference 59a.

The oscillation movement of the above mentioned arm 69a is imparted to an oscillating plate 73, whereby a control pin 76 (FIG. 8) fixed proximate to the circumference of the impression cylinder 4 is moved closer to, or away from, the shaft 5 of the impression cylinder. Namely, the pin 76 takes a retreated position from the shaft 5 when the outer edge of the detecting pin 63 is protruded from the circumference of the impression cylinder, whereas said pin 76 takes a closer position relative to said shaft 5 when the feeler pin 63 is retreated from the circumference of said impression cylinder 4.

Let the impression cylinder 4 rotate in a counterclockwise direction when the aforesaid pin 76 takes an outside position, viz, when the outer edge of the feeler pin 63 is in a protruded position as shown in FIG. 11, the pin 76 kicks the lower end of 18b of a wire arm 18 as shown in FIG. 5, causing the stopper member 16 to rotate in a clockwise direction around a shaft 17.

However, if the clamp finger 50 caught the copy sheet, the pin 76 takes an inside position and hence, the wire arm 18 is not activated. Referring to FIG. 1, let the plate cylinder 2, the blanket cylinder 3 and the impression cylinder 4 are respectively rotated in the arrow directions. The rotation of the impression cylinder 4 provides the bell crank 37 with a reciprocating movement through a fan-shaped cam 40 as shown in FIG. 3, causing thrust lever 32 to be connected to the bell crank 37 to make the same movement. In this case, however, since the oscillating plates 29 and 24 which support the friction wheels 30 are prevented from this oscillation movement by a lever 45 as shown in FIG. 1, said thrust lever 45 merely makes an idle motion.

If the oscillating plate 24 supporting friction wheels were maintained in a stationary position, that is to say, when the copy sheets are not being fed, the pin 76 on the oscillating plate 73 provided on the impression cylinder 4 takes a position shown in FIG. 5. By turning the impression cylinder 4 under such status as hereinabove described, the pin 76 kicks a lower end 18b of the wire arm 18 at each rotation of the impression cylinder 4, providing a stopper member 16, integrated with a wire arm 18, with an oscillation movement. On the other hand, cam plate 15, which rotates integral with said impression cylinder 4, provides a reciprocating movement to an oscillating arm 12.

The movement of said oscillating arm 12 around a shaft 11 as a fulcrum causes the operating lever 6 to rotate in a clockwise direction around an eccentric shaft 5a against elasticity of a spring 9, whereby the movable lever 7 connected with said operating lever 6 through a spring 8 is also rotated in the'same direction. This, in turn, rotates an eccentric shaft 5a carrying, secured thereon, said movable lever 7, thereby pressing the impression cylinder 4 to a blanket cylinder 3 supported by a shaft 5 integrated with said eccentric shaft 5a.

The blanket cylinder 3 and the impression cylinder 4 are thus brought into contact to each other at each rotation of the cam plate 15 when the angular cam 15a thereof pushes out the oscillating arm 12, whereupon, of course, the indentation formed on the circumference of said impression cylinder 4 is adapted to face the blanket cylinder 3 as shown in FIG. 5. Furthermore, as shown in FIG. 5, the pin 76 pushing out the wire arm 18 is adapted to be always synchronous with the pushing motion of the angular cam 15a hereinabove described. Therefore, even if the operating lever 6 movable by a roller 10 of said oscillating arm 12 were rotated clockwise from the position shown in FIG. 1, the stage 16a of the stopper member 16 would not engage with the bent portion of the operating lever 6. The engaged status of the stopper member 16 with the operating lever 6 as shown in FIG. 4 is realized only when the copy sheet is caught by the clamp fingers 50. In other words, in a case when the copy sheet was not caught by said clamp finger 50, the stopper member 16 takes such a position as to enable engagement with the operating lever 6 by the action of the wire arm 18 and the pin 76. It follows, therefore, that under circumstances where the copy sheets are not being fed, the blanket cylinder 3 and the impression cylinder 4 come temporarily into contact with each other at the indentation 48, instead of revolving continuously with respective circumferences in contact with each other, thus avoiding the inked image on the blanket cylinder 3 from being transferred onto the impression cylinder. Explanation hereinabove described applies when the copy sheets were not fed.

The operations of respective mechanism when the copy sheets were fed one sheet at a time by the friction wheels are described hereafter. Referring now to FIG. 1, if an end 45b of a lever 45 is moved in the direction of an arrow and disengaged from the oscillating plate 24 to release the latter from an oscillation movement, the oscillating plate 24 is provided a reciprocating movement by a vertical motion of a thrust lever 32 (refer FIG. 3). Instantaneous with the friction wheels 30 being brought into contact with the copy sheets, the gear 22 is rotated in the arrow direction by the action of a bent lever cooperating with the cam 42 (refer FIG. 1) through a connecting link 21, causing said friction wheels 30 to rapidly rotate in a clockwise direction and deliver one topmost copy sheet from copy sheets piled on the paper stack.

The copy sheet thus delivered is caught at its leading edge by clamp fingers 50 and drawn between the blanket cylinder 3 and the impression cylinder 4. When the copy sheet is thus correctly delivered, the pin 76 provided on the impression cylinder takes an inner position to disengage said pin 76 from a wire arm 18. As a result of the wire arm 18 taking a position shown in dotted line 18', the stopper member 16 integrated with said wire arm takes a position shown in dotted line 16' wherein stage 16a of said 16 is enabled to stop the operating lever 6.

In the aforesaid status wherein the stopper member 16 is put in a position to hook the operating lever 6, and if the operating lever 6 were rotated as shown in FIG. 4 in a clockwise direction around an eccentric shaft 5a by the actions of a cam plate 15 and the oscillating arm 12, the shoulder 16a of the stopper member 16 hooks the bent portion 60 of the operating lever 6, stopping thereby the returning movement of the operating lever 6 which would otherwise have occurred by the force of a spring 9, whereby the blanket cylinder 3 and the impression cylinder 4 are kept in contact with each other, allowing the copy sheet travelling therebetween to be printed.

While the engagement between said operation lever 6 and the stopper member 16 is maintained during a period when copy sheets are continuously being fed, the operating lever 6 and the stopper member 16 are disengaged by the action of the pin 76 of the impression cylinder 4 when the copy sheets are emptied or when a copy sheet is not caught for some reason or other by a clamping device of the impression cylinder, whereby the blanket cylinder 3 and the impression cylinder 4 are separated.

The pressure with which the blanket cylinder 3 is brought in contact with the impression cylinder 4 can be suitably determined by colliding a movable lever 7 with a cam 77 and thereby limiting the rotating angle of the eccentric shaft 541 integrated with said movable lever 7. The aforementioned cam 77 is rotably mounted on the side wall, the shaft 78 of said cam '77 being fixed with a rotation adjustable knob (not shown) at the outside of the printing machine.

Referring now to FIG. 13 illustrating another embodiment of this invention, an arm 169, which is provided an oscillation movement by a cam plate 59, is provided an extension 169a integrated therewith, so that, when the impression cylinder 4 is rotated with the pin 63 in a protruded position, said extension 169a is adapted to kick an arm 118 (a member corresponding to a wire arm 18 in FIG. 5) substantially integral with a stopper member 16 and the operating lever 6 can be either enabled to engage with each other, or disengaged from each other, as the case may be, eliminating thereby the necessity of incorporating the oscillation plate 73.

It goes without saying that a device embodying this invention is not limited to the example embodiments heretofore described, but inclusive of all variations which fall within the scope of the inventive step of this invention.

We claim:

1. In an offset printing machine with impression, plate, and blanket cylinders, and means for feeding copy paper onto the periphery of said impression cylinder, characterized by means for separating said impression and said blanket cylinders upon malfunction the copy paper, feeding mechanism for the copy paper, copy sheet clamping fingers arranged axially on a suitable bar in a recess on the periphery of said impression cylinder, a row of feeler pins in said recess projecting radially out- Wardly adjacent said clamping fingers, a control pin adapted to project above the peripheral surface of said impression cylinder, said control pin located in advance of said row of feeler pins and clamping fingers as said impression cylinder rotates, means mechanically interconnecting said control pin and said row of feeler pins so that when the latter projects radially from the surface of the impression cylinder so will the former, cam and lever means for pressing together said blanket and impression cylinders when the former carries a copy sheet properly positioned thereon and for separating said cylinders when said copy sheet is improperly positioned or not on the impression cylinder at all, means pivotally mounted independently of said cylinders but in the path of said control pin as said impression cylinder rotates, and said last named means adapted to control the position of said cam and lever means so as to provide for separation of said blanket and impression cylinder when there is no copy sheet properly located on the latter cylinder.

2. A device as described in claim 1, wherein said last named means operates as a stop on said cam and lever means to prevent separation of said impression and blanket cylinders.

3. A device as described in claim 1, wherein said last named means comprises an arm pivoted at one end with a stop shoulder at the other end adapted to cooperate with said cam and lever member.

4. A device as described in claim 1, wherein said cam and lever means comprises a pivoted lever rotatable in a counterclockwise direction by a circular cam and a spring loaded bifurcated lever rotatable in a clockwise direction by said pivoted lever.

References Cited UNITED STATES PATENTS 1,351,175 8/1920 Lehr 101-234 2,392,391 1/ 1946 Kaddeland 10l247 X 3,046,881 7/1962 Jurny 10l2l8 WILLIAM B. PENN, Primary Examinler.

FRED A. WINANS, Assistant Examiner.

US. Cl. X.R. 101-409

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