US2694976A

US2694976A - Plate lock-up mechanism for printing machines

Info

Publication number: US2694976A
Application number: US165029A
Authority: US
Inventors: William F Huck
Original assignee: HUCK CO
Current assignee: HUCK CO
Priority date: 1950-05-29
Filing date: 1950-05-29
Publication date: 1954-11-23
Anticipated expiration: 1971-11-23

Description

W. F. HUCK Nov. 23, 1954 PLATE LOCK-UP MECHANISM FOR PRINTING MACHINES 2 Sheets-Sheet 1 Filed May 29, 1950 SMQW ATTORNEY INVENTOR Wuuan E HUcK.

W. F. HUCK Nov. 23, 1954 PLATE LOCK-UP MECHANISM FOR PRINTING MACHINES 2 Sheets-Sheet 2 Filed May 29, 1950 lA/Vi/VTOR Wmum E H um. B).-

ATTOH/YE/ United States Patent L TE LOCK-UP MECHANISM FOR PRINTING MACHINES Wil am F- 'Huck, Forest Hi s, N- Y, assiguor to Huck This invention relates to printing machines and more particularly to means for holding, tensioning and locking-up a flexible printing plate on the plate'cylinder of a rotary printing machine' Many different types and kinds of mechanisms have been devised for securing flexible printing plates to plate cylinders of printing machines. However, advances in the printing art have demanded greater and greater accuracies in printing with the result that the plate holding devices heretofore used have not always proved entirely satisfactory. Therefore, one of the principal objects of the present invention is to provide an improved plate holding device for printing machines.

Another object of the invention is to provide an improved plate lock-up mechanism in which the maximum available force of a spring maybe used to ciarnp and tension the plate.

A further object of the invention is to provide an improved plate lock-up mechanism in which both ends of the plate may be accurately registered and. ripped.

A still further object of the invention is to provide ,an improved plate lock-up mechanism in which both ends of the plate are held by the same type of clamping bar.

Other important objects of the invention will be applarent from the following specification and appended c aims.

In the accompanying drawings, which form part of this specification:

Fig. 1 is an elevational view of a portion of a printing machine showing a plate cylinder equipped with 'a plate holding and loclleunv m h i m mbody ng the p esent invention, portionsof the mechanism having been cut away to show internal details;

Fig. 2 is a cross sectional view of a portion of the. plate cylinder as seen along the line 2-2 of Fig. 1,. the means or n n g he ra l ng end of the. plate b ingshown in the unlocked or open position.

Fig. 3 is a composite, cross-sectional View of the plate cylinder, the right hand portion of Fig, 3 being viewed. o g e l n 3+ of Fig. 1, and he left hand portion being viewed along the line 3' 3 of the same figure;

Fig. 4 is a viewsimilar to Fig. 1 but showing a modiw fied form of the invention;

Fig. 5 is a crpss sectional view as seen along the line 5-5 of Fig. 4; and

Fig. 6 is, a composite cross sectional view similar to Fig. 3 but as viewed along the line 6.-6. and 6z+6" of Fig. 4.

Certain subject matter disclosed but not claimed herein, constitutes the claimed subject matter of my copending divisional patent application, Ser. No. 407,766, filed February 2, 1954.

Referring more in detail, to the drawings, which accompany and form part of this specification, and especially to Figs. 1, 2, and 3', the numerals 11-.-11"' indicate a pairof side frames of a printing machine. These frames support a pair of bearing bushings 12-12 that rotatably support a pair of journals 13--13" formed on opposite ends of a plate cylinder indicated generally by the numeral 15. The plate cylinder comprises a pair of spaced end discs 16-16, connectedrby, a cylindrical" shell 17, and having a gap 18, that extends longitudinally. the total distance between the,

discs

16 and 16", which gap allows access to a plate lock-up. mechanism, later. to be described.

The plate cylinder carries a flexible printing plate:

(a 20, of which the leading end is held to the cylinder by a leading-end plate-clamp 21 comprising a lower clamp bar 22 and an upper clamp bar '23. The lower bar 22, and thus the clamp 21 as a whole, is held in a groove 24 formed in and extending the length of the shell 17. The exact position of the clamp 21, and thus the position of printing matter (not shown) on the plate circumferentially and axially with respect to the cylinder 15 is governed by a register pin carried by the cylinder 15. This pin 25 enters a register hole 26 formed .in an appropriate portion of the bar '22 of the clamp 21. The upper bar 23 is held to the lower bar '22 by a plurality or spaced, counter-sunk screws '27.

The means for holding the clamp 21 in the groove 24 comprises a plurality of spaced screws '28 which are screwed through threaded holes formed in a hook shaped portion of the plate cylinder 15. The front end of these screws engage an inclined edge 29 formed on the leading edge of the lower clamp bar 22. It will be apparent that tightening of the screws 28 not only forces the clamp bar 22 against an edge 30 formed on the cylinder 15, but, due to the incline 29 and a recess 31 formed in the shell 17, also retains the bar 22 and thus the whole clamp 21 on the cylinder 15.

From the clamp 21 the flexible printing plate 26 is wrapped in a clockwise direction around the cylinder shell 17, the trailing end of the plate 20 being held to the cylinder and tensioned by a tensioning mechanism 40. O ne part of the tensioning mechanism 40 comprises a trailing-end plate-clamp 21 which is a duplicate of the leading-end plate-clamp 21 hereinbefore described. The parts that appear in both clamp structures will be designated by the same numerals except that the numeralsdesignating the plate-clamp associated with the tensioning mechanism 40 will be primed, as for example 22 -23, etc. Thus the plate clamp 21', associated with the mechanism 40, has a lower clamp bar 22', and an upper clamp bar 23, the lower bar 22 being held in a groove 24' formed in a tensioning block 41 later to be described. The exact position of the clamp 21' and thus the position of printed matter (not shown) on the plate, axially, with respect to the block 41 is governed by a register pin 25 carried by the block 41 and entermg a register hole 26 formed in an appropriate portion of the bar 22'. The upper bar 23 is held to the lower bar 22 by a plurality of spaced screws 27'. The means for holding the clamp 21 'in the groove 24 comprises a plurality of spaced screws 28' screwed through, threaded holes formed in a hook shaped portion of the tensioning block 41. The front end of these screws engage an inclined edge 29 formed on the trailing edge of the lower clamp. bar 22'. As in the previous instance, it will be apparent that tightening the screws 28' not only forces the clamp bar 22 against an edge 30' formed on the tensioning block 41 but, also retains the bar 22 and thus the Whole Clamp. 21 on the tensioning block 41.

As best seen in Fig. 1, the tensioning block 41 is shown as extending the distance between the end discs 16 and 16], and as seen in Fig. 2 the portion of the block 41 nearest the axial center of the cylinder 15 is pivotally mounted on a rod or shaft 42 which extends the length of the cylinder 15, the ends of the shaft 42. being held in the discs 16-16. Intermediate portions of the shaft 42 are supported by a pair of bases or lugs 44-44, that are formed integral with the cylindrical shell 17 and project inwardly therefrom. The block 41 is provided with a plurality of rectangular holes 47, in this case three, the purpose of these holes will presently appear.

At this point it might be well to note that the plate clampv 21, hereinbefore described, is located on the free end of the block 41. Thus the clamp 21" becomes a movable clamp that may be moved in a trailing direction with respect to the cylinder 15 to tension the trailing end of the plate 20.

The mechanism for moving the free end of the block 41, and thus tensioning the plate 20, includes an oscillatory or rotary shaft that extends the full length of cylinder 15,, the axis of the shaft 55. being parallel 3 to the axis of the cylinder 15. Opposite ends of the shaft 55 are journaled in the end discs 16-16 and 1ntermediate portions of the shaft 55 are journaled in holes 49 in the lugs or bosses 44-44. The shaft 55 is provided with a plurality, in this case three, slots or notches 56.

A spring rod 57 passes through each of the holes 47 in the block 41. One end of each of the spring rods 57 is fulcrumed on a pin 58 that is embedded in one of the notches 56. Each pin 58 is held in place by a pair of screws 60-60 that enter threaded holes radially formed in the shaft 55. A helical spring 62 surrounds each of the rods 57 and these springs are compressed between shoulders 63 formed on the ends of each of the rods 57 and spring receiving recesses 64 formed in a shaft 50 journaled in a plurality of concentric holes 51 formed in the block 41. The free end of each of the spring rod '7 passes through a diametrical hole 67 in the shaft 50, and a pin 65 passes transversally through the free end of each of the spring rods 57, it being noted that the 2.

pins 65 are on the side of the shaft 50 remote from the spring recesses 64. The pin 65 prevents the end of the rod 57 from passing through the hole 67 in the shaft 50. The pin 65 also preloads the spring 62.

As best seen in Figs. 1 and 3, the shaft 55 carries, on

its right end 70, a plurality of worm gear teeth 71 that do not extend around the complete circumference of the shaft 55. The teeth 71 are in mesh with a worm 72 positioned in a substantially radially disposed hole 73 formed in the end disc 16'. The worm 72 is held in place by having a lower journal 75 journaled in a bearing 76, and by means of an upper journal 78 supported in a screwed bushing 79 held by threads 80. An extension of the upper journal 78 is squared and may be engaged by a T-wrench 82, shown in dash-dot lines in I Fig. 3. The end thrust of the worm 72 is taken by a pair of washers 83-83.

The operation of the hereinbefore described plate lockup mechanism is as follows: When it is desired to apply a flexible printing plate to the surface of the cylinder 15, the wrench 82 is attached to the square end of the journal 78 and the worm 72 and worm gear 71 are turned and thus the shaft 55 is turned counterclockwise until the spring rod 57 moves to the left as shown in Fig. 2. This moves the tensioning mechanism 40 in a leading direction toward the shell 17. Then the printing plate 20, which has secured to its leading end the clamp 21 and to its trailing end the clamp 21, is brought to the printing cylinder 15. It will be understood that the

clamps

21 and 21 had previously been secured to the plate and in register therewith. Several different means may be used to effect this preregister, but I prefer to preregister the clamps 21 and 21' with respect to the plate by means of a mechanism for preregistering printing and other plates disclosed in my patent application Serial No. 127,191, filed November 14, 1949.

During the preregistering the leading end of the printing plate is secured to the leading plate-clamp 21 by means of the bars 22-23 and screws 27. The printing plate 20 is wrapped in a clockwise direction around the cylinder 15 and the trailing end of the plate is secured to the relaxed tensioning mechanism by means of the plate clamp 21. When the plate 20 is secured at both ends, turning of the T wrench 82 rotates the worm 72, the gear 71 and the shaft 55, the latter in a clockwise direction (Fig. 3) thereby compressing the spring 62 and causing the block 41 to turn clockwise about the rod 42. This pulls on the trailing end of the plate 20 and tensions it.

From the above, it will be seen that the spring 62 is comparatively small and stiff, the maximum force of the spring in compression being used when the plate is locked-up. This provides a very high tension in the printing plate 20. Since there are a plurality of springs 62 positioned across the cylinder 15, it will be understood that the plate 20 is in uniform tension throughout. To unlock the plate 20, the shaft is rotated counterclockwise (Fig. 2) to release the spring 62 to move the rod 57 and the pin to the left and thus to release the tension in the plate 20. This provides an extremely accurate means for securing and tensioning or lockingup a printing plate on a plate cylinder, in which both ends of the plate are clamped accurately and registered.

Figs. 4, 5 and 6 illustrate a modified form of plate lock-up comprising many parts that are identical with parts shown in Figs. 1, 2 and 3. The parts which are common to both figures are designated by numerals that are less than and, since these parts have been described hereinbefore, a detailed description thereof need not in every case be repeated. The printing machine of Figs. 4, 5 and 6 includes side frames 11-11, bearings 12-12, journals 13-13 and a plate cylinder 15 having end discs 16-16' connected by the shell 17 having a gap 18. As in the former case, a printing plate 26 is carried by the cylinder 15, and the leading end of the plate 20 is clamped and held by the leading-end plate clamp 21 preferably having structure identical with the clamp 21 hereinbefore discussed. The trailing end of the plate 20 is tensioned and/or locked to the cylinder by a plurality of tensioning plate clamps that are spaced longitudinally of the cylinder 15. In the modification illustrated in Figs. 4, 5 and 6 there are three tensioning clamps 140. However, it will be understood that any suitable number of clamps may be employed depending on the length of the printing cylinder 15 and the axial length of the plate 20. Since the tension clamps 140-140-140 are identical, only one will be described in detail. Each clamp has a substantially radially disposed, lower jaw plate 141 and an upper jaw plate 148. The inner end of the jaw plate 141 is fulcrumed on a rod 42 which extends axially of the cylinder 15 and which is supported by passing through apertures in the end discs 16-16, as well as by passing through apertures formed in the pair of lugs 44-44 formed integral with the shell 17 and extending substantially radially.

inside thereof. The jaw plate 141 has an aperture 143 and the plate 141 extends substantially radially outwardly from the rod 42 and the free end of the plates 141 is spaced just a short distance below the outer circumference of the cylinder 15. The jaw plate 141 is substantially in the form of a rectangular plate, and the outer or free end of the plate acts as a clamping surface 145. A pair of spaced lugs 146-146 extend at right angles to the jaw plate 141 adjacent the free end thereof and both of the lugs are apertured to accommodate a pivot pin 147, the latter extending parallel to and spaced from the jaw plate 141.

The pin 147 acts as the pivot for the upper jaw plate 148, the main portion of which is in the form of a rectangular plate of smaller size than the plate 141 and having an upper clamping dog 149 that extends outwardly from one end of the plate 148 and substantially normal thereto. The plate 148, being pivoted as it is to the plate 141, is positioned adjacent one side of the plate 148 and, in the position shown in Fig. 5, the two plates are substantially parallel. A helical compression spring 153 is imbedded in recesses formed in adjacent portions of the

plate

141 and 148, thus the spring exerts a force that tends to separate the

plates

141 and 148. A clamping surface 150 is formed on the dog 149 and is positioned opposite the clamping surface 145. Thus the clamping surface 150 cooperates with the previously described clamping surface of the plate 141 to grip the trailing end of the printing plate 20. The main body portion of each jaw plate 148 is indicated by the numeral 151, and this portion is provided with an aperture 152 later to be discussed.

The plate cylinder 15 carries an oscillatory or turnable shaft 55 that extends the full length of the cylinder and is parallel to the axis thereof. The shaft 55 is located on the side of the lower jaw plate 141 which is remote from the side thereof to which the upper jaw plate 148 is adjacent. Opposite ends of the shaft 55 are journaled in the end discs 16-16 and intermediate portions of the shaft 55 are journaled in the lugs 44-44 as previously described. The shaft 55 is provided with a plurality of slots or notches 56, the number of slots 56 being equal to the number of tensioning clamps 40.

A spring rod 57 passes through each of the apertures 152 in each upper jaw plate 148 and also passes through the aperture 143 formed in the plate 141. One end of each spring rod 57 is fulcrumed on a pin 58 that is embedded in grooves 56 formed in the shaft 55, there being one groove for each tensioning clamp 140. Each pin 58 is held inplace by a pair of screws 60-60 that enter threaded holes radially formed in the shaft 55. A helical spring 62 surrounds the rod 57 and is compressed between a shoulder 63 formed on the end of the rod 57 and a spring receiving recess 164 formed in the side of the upper plate 148 that is adjacent to the lower plate 141.

A pin 65 passes transversally through the free end of the spring rod 57, it being noted that the pin 65 is on the side of the plate 148 that is remote from the spring recess 164, thus the pin is adjacent to the face remote from the plate 141. The pin 65 engages one face (Fig. 5) of the plate 148 and thus prevents the plate 148 from passing over the end of the rod 57. The pin 65 also preloads the spring 62 which along with the rod 57 passes through the aperture 143 in the plate 141. The shaft 55 and the means for operating the same are identical with that shown in Figs. 1 through 3 and thus will not he redescribed.

The operation of the hereinbefore described plate lock-up mechanism is as follows:

When .it is desired to apply a flexible printing .plate to the surface of the cylinder the wrench 82 is attached to the squared-end .of journal 78and the worm '72 and worm .gear 71 are turned until the spring rod 57 moves inwardly against the pressure of the pre-loaded spring 62. This opens .the jaws of jaw plates 141-148 as shown in Fig. 5. Then the leading end of the printing plate is secured by means of the plate clamp 21 and and screws 27. The printing plate 20 is then wrapped around the cylinder and the trailing end of the plate is placed between the clamping

surfaces

145 and 150. Turning of the T wrench 82 rotates the worm 72, the gear 71 and the shaft 55, the latter in a clockwise direction (Fig. 6). This causes the spring rod 57 and the spring 62 to move toward the. right as seen in Fig. 6, thereby separating the

plates

141 and 148 about the pivot 147. This first closes the clamping surfaces 145 and 150 and grips the trailing edge of the plate 20. When the jaws are fully closed further clockwise rotation (Fig. 6) of shaft 55 causes the plate 141, which of course carries the plate 148, to rotate about the rod 42. This results in the tensioning of the plate 20 and at the same time causes maximum compression of the spring 62.

From the above, it will be seen that the spring 62 is comparatively small and stiff. This provides a very high tension in the printing plate 20. Since there are a plurality of spring biased plate clamps 140 positioned across the cylinder, it will be understood that the plate 20 is subjected to uniform tension for its entire width. To unlock the plate 20, the shaft 55 is rotated counter clockwise (Fig. 5) which in turn releases the spring tension when pin 65 engages the outer surface of the clamp plate 148. As the shaft 55 is turned and the pin 65 moves, the tension exerted on the plate 20 is first removed, then the spring 153 is compressed and the plate 48 is moved about its fulcrum 147 to open the clamping surfaces 145 and 150. When the clamp plates 148 abuts against the plate 141, and the latter against the trailing edge of the gap 18 the trailing end of the plate 20 is fully released.

From the foregoing it will be noted that the instant invention provides a plate lock-up mechanism for printing machines in which the spring, that tensions the plate, is under maximum compression when it is performing these operations.

Having thus set forth the nature of my invention, what I claim and desire to secure by Letters Patent of the United States is:

1. A plate lock-up for holding and tensioning one end of a flexible printing plate to the plate cylinder of a printing machine, said plate lock-up comprisinga shaft journaled in said plate cylinder, means for turning said shaft, a spring rod having one of its ends pivotally connected to said shaft, a compression spring surrounding said spring rod, a tensioning block pivotally carried by said plate cylinder, a spring seat on said spring rod, a shaft turnably carried by said tension block and having an aperture through which said spring rod extends, a spring seat on said last named shaft, a pin carried by said spring rod and positioned on the side of said last named shaft that is remote from the said seat, and means carried by said tensioning block for engaging and holding one end of said printing plate.

2. Means for holding a flexible printing plate to the plate cylinder of a printing machine, comprising, a plateclamp secured to the leading end of said printing plate; a second plate-clamp secured to the trailing end of said printing plate; a fixed mounting having a groove formed to receive one of said plate-clamps; a movable mounting having a groove to receive the other of said plate-clamps; a compression spring of which one end of secured to said 6 movable moun ing; an Q Pressing an en g ng the other end of said spring for compressing said compresslql spring to move said movable mounting and tension said printing plate, each of said plate clamps comprising an upper and a lower clamp bar positioned in its respective groove and each of said grooves having an abutment edge against which the lower clamp bar is engaged, an inclined surface on each of said lower clamp bars, and a screw, of which the axis is perpendicular to said inclined surface, said screw engaging said inclined surface and thereby forcing said lower clamp-bar circumferentially of said cylinder and into engagement with said abutment edge.

3. Means for holding a flexible printing plate to the plate cylinder of a printing machine, comprising, means securing .one end of the printing plate to the plate cylinder; a tensioning block extending substantially the full axial length of the cylinder, said block being provided with a plurality of concentric holes; means pivotally mounting one portion of said tensioning block on said cylinder; means securing the other .end of the printing plate .to the free end of said tensioning block; an abutment shaft having a plurality of diametrical holes and saidabutment shaft being journaled in the concentric holes in said tensioning block; a spring-rod passing through each of said diametrical holes in said abutment shaft; a helical compression spring surrounding each of said spring-rods and each of said springs engaging said abutment shaft; and means for compressing said springs and thereby causing said compression spring to move said abutment shaft, said block and said second plateclamp in a direction to tension said printing plate.

4. Means for holding a flexible printing plate to the plate cylinder of a printing machine, comprising, means securing one end of the printing plate to the plate cylinder; a tensioning block extending substantially the full axial length of the cylinder, said block being provided with a plurality of concentric holes; means pivotally mounting one portion of said tensioning block on said cylinder; means securing the other end of the printing plate to the free end of said tensioning block; an oscillating shaft journaled in said cylinder; an abutment shaft having a plurality of receiving recesses and a plurality of diametrical holes and said abutment shaft being journaled in the concentric holes in said tensioning block; a headed spring-rod passing through each of said diametrical holes in said abutment shaft; means for pivotally mounting one end of each of said spring-rods on said oscillating shaft; a helical compression spring surrounding each of said spring-rods and each of said springs engaging the head of its spring-rod and one of the receiving recesses of said abutment shaft; and means for turning said oscillating shaft and thereby causing the head of said spring-rod to compress said compression spring to move said abutment shaft, said block and said second plate-clamp in a direction to tension said printing plate.

5. Means for holding a flexible printing plate to the plate cylinder of a printing machine, comprising, means securing one end of the printing plate to the plate cylinder; a tensioning block extending substantially the full axial length of the cylinder, said block being provided with a plurality of spaced rectangular holes and a plurality of concentric holes; a pivot rod extending substantially the full axial length of the cylinder; means pivotally mounting one portion of said tensioning block on said rod; means securing the other end of the printing plate to the free end of said tensioning block; an abutment shaft having a plurality of receiving recesses and a plurality of diametrical holes and said abutment shaft being journaled in the concentric holes in said tensioning block; a headed spring-rod passing through each of said rectangular holes in said block and also passing through the diametrical holes in said abutment shaft; means for pivotally mounting one end of each of said spring-rods in one of the notches of said oscillating shaft; a helical compression spring surrounding each of said spring-rods and each of said springs engaging the head of its spring-rod and one of the receiving recesses of said abutment rod shaft; and means for turning said oscillating shaft and thereby causing the head of said spring-rod to compress said compression spring to move said abutment shaft, said block and said second plate-clamp in a direction to tension said printing plate.

6. Means for holding a flexible printing plate to the plate cylinder of a printing machine, comprising, a first plate-clamp secured to the leading end of the printing plate; means for securing said first plate clamp to the cylinder; a second plate-clamp identical with said first plate clamp and secured to the trailing end of said printing plate; a tensioning block extending substantially the full axial length of the cylinder, said block being provided with a plurality of spaced rectangular holes and a plurality of concentric holes; a pivot rod extending substantially the full axial length of the cylinder; means pivotally mounting one portion of said tensioning block on said rod; means securing said second plateclamp to the free end of said tensioning block; an oscillating shaft journaled in said cylinder and extending substantially the fully length thereof, said oscillating shaft being provided with a plurality of notches; an abutment shaft having a plurality of receiving recesses and a plurality of diametrical holes and, said abutment shaft being journaled in the concentric holes in said tensioning block; a headed spring-rod passing through each of said rectangular holes in said block and also passing through the diametrical holes in said abutment shaft;

means for pivotally mounting one end of each of said spring-rods in one of the notches of said oscillating shaft;

a helical compression spring surrounding each of said References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,215,344 Clark Feb. 13, 1917 1,715,893 Bertinetti et a1 June 4, 1929 1,913,392 Jacobson June 13, 1933 2,088,862 Lang Aug. 3, 1937 2,123,997 Jirousek July 19, 1938