US2243195A

US2243195A - Blanket cylinder

Info

Publication number: US2243195A
Application number: US212860A
Authority: US
Inventors: Curtis S Crafts
Original assignee: GOSS PRINTING PRESS CO Ltd
Current assignee: GOSS PRINTING PRESS Co; GOSS PRINTING PRESS CO Ltd
Priority date: 1938-06-10
Filing date: 1938-06-10
Publication date: 1941-05-27
Anticipated expiration: 1958-05-27

Description

5 Sheets-Sheet 1 Filed June 10, 1958 May 27, 1941. c. s. CRAFTS 2,243,195

aLANkET CYLINDER Filed June 10, 1938 3 Sheets-Sheet 2 g g i Patented May 27, 1941 BLANKET CYLINDER Curtis S. Crafts, Oak Park, 111., assignor to The Goss Printing Press Company, Chicago, 111., a corporation oflllinois Application June 10, 1938, Serial No. H2560 '7 Claims.

The present invention relates to printing presses and more particularly to a novel and improved blanket or impression cylinder for rotary printing presses.

Objects and advantages of the invention will be set forth in part hereinafter andin part will be obvious herefrom, or may be learned by practice with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The invention consists in the novel parts, constructions, arrangements, combinations and improvements herein shown and described.

The accompanying drawings, referred to here.- in and constituting a part hereof, illustrate embodiments of the invention, and together with the description, serve to explain the principles of the invention.

Of the drawings:

Figure 1 is a side elevation, with certain parts being shown in section, of a typical embodiment of the present invention;

Figure 2 is a cross section taken on the line 2-2 of Figure 1;

Figure 3 is a cross section taken on the line 3-3 of Figure 1;

Figure 4 is a fragmentary end elevation of the impression cylinder shown in Figures 1, 2 and 3.

The present invention has for its object the provision of a novel and improved blanket or impression cylinder for use in high speed rotary printing presses. A further object is the provision of an improved blanket cylinder in which separate means are provided for securing and tensioning a plurality of sheets on the surface of the cylinder and these means permit the outer sheet to be released and lifted from the surface of the cylinder without disturbing the other sheet or sheets. A further object of the invention is the provision of a strong blanket cylinder having extremely narrow slots longitudinally thereof through which the surfacing sheets are clamped, thereby providing for the printing of sheets with very narrow margins between adjacent page impressions.

In accordance with an illustrative embodiment of the present invention, the blanket cylinder comprises a relatively long and narrow cylinder which is provided on its surface with one or more longitudinally extending slots which open into corresponding cavities formed within the body of the cylinder, these cavities being of considerably larger size than slots, but not sufficiently large as to destroy the rigidity of the cylinder.

Along one side of each slot, and within the periphery of the cylinder, the cylinder is provided with pins which are adapted to pierce and secure the ends of two or more sheets of paper or other material used for the impression surface of the cylinder. Within the cavity is provided one or more reel rods, which may be long and of rather small diameter, slotted for most of their length, and adapted to receive the other end of the under sheet held by the pins, and as this reel rod is rotatably mounted the under sheet may be drawn tightly about the surface of the cylinder by turning this rod. In case a second reel rod is provided within the cavity, it may serve to tighten the upper sheet on the cylinder surface. Suitable ratchet means are provided for holding the reel rods in the position to which they are turned, and manual means may be provided for turning them to tighten the under sheets and top as much as is necessary. For clamping and tightening the outer sheet, when only a single reel rod is provided, there is provided a jaw member which is movably mounted within the cavity and is adapted to clamp the outer sheet over the pins pressing and pulling it against the ends of the previously secured sheets, and so that the outer sheet is drawn and stretched as it is firmly clamped. The clamping jaw is preferably angularly movable about one of the reel rods and they may be coaxially mounted for compactness, although they are separately actuated and the clamping jaw may be released without releasing the under sheet. Spring means are provided for holding the clamping jaw in or out of its clamped position.

The present invention is particularly useful in connection with the printing of stereotype or other relief printing plates, although in certain of its aspects it is applicable to other forms of rotary printing presses. When used for printing from stereotype or other relief printing plates, the impression blanket is generally used as the under sheet and the overlay or other makeready may be supported on this sheet, while the outer sheet is generally the pacln'ng or impression sheet. Thus, the outer sheet may be replaced in case it becomes soiled or worn, and the makeready may be shifted for register or otherwise varied without disturbing the stretch which has already been imparted to the blanket during a previous run. a Itwill be understood that the foregoing general description and the following detailed description as well, are exemplary and explanatory of the invention but are not restrictive thereof.

Referring now in detail to the illustrative embodiment of the invention as shown in the accompanying drawings, the invention is shown as applied to the blanket cylinder of a rotary relief printing press which cylinder is two pages in circumference, and may be several pages in width. The printing cylinder It) is provided at its ends with shafts II by which it is rotatably supported and driven in the conventional manner. This cylinder is provided with narrow slots 26 extending longitudinally of the cylinder for at least one or more full page lengths, and the number of slots is preferably the same as the circumference of the cylinder as measured in pages. Slots 20 are provided with inwardly extending and divergent side walls 2| and 22 and open into the larger 1ongitudinally extending cavities 24 formed within the body of the cylinder, these cavities containing the clamping and tensioning mechanism for the sheets forming the impression surface on the periphery of the cylinder.

Means are provided for securing a plurality of sheets by one end within the slot, and these sheets may comprise the impression blanket and the outer sheet or draw sheet. As embodied, pins 25 extend inwardly into the slot 20 from side wall 2| in which they are mounted, and these pins are adapted to retain the sheets and 3| in the manner shown in Figure 2.

Means are provided for securing the other ends of the sheets and for tensioning the sheets and these means are also located within each cavity 24. As embodied, there is provided a reel rod 33 which extends from beyond one end of the cylinder It to a point slightly beyond the center of the cylinder, and the rod is rotatably supported parallel to the cylinder axis by means of its reduced

ends

35 and 35 by which ends it is journalled in corresponding recesses in the cylinder. Reel rod 33 is slotted throughout a considerable portion of its length, as at 40, and is adapted to receive one end of the blanket or under sheet 30,

this end being passed through the slot 43 after f.

which the reel rod is turned to wrap the sheet end around it. Rod 33 is provided at its extremity with a squared portion 3'! to which a wrench may be fitted for easy turning of the rod.

Means are provided for clamping the other end of the sheet 3|, and these means comprise a jaw member 43 positioned in the slot 23 and having teeth on it adjacent to the side wall 2|. The jaw member is also provided with apertures 44 to fit over the sharpened ends of the sheet-holding pins 25. Jaw member 43 forms the outer extension of a hollow member 46 which is relatively long and substantially encloses and surrounds the reel rod 33, being preferably coaxially mounted therewith, and rotatably supported upon the ends of reel rod 33 just beyond its slotted portion. As jaw 43 is moved towards the surface 2|, the end of sheet 3| is first punctured by the pins 25, and thereafter the sheet 3| is further tensioned and clamped in place by the pressure exerted by jaw 43 on it.

Means are provided for securing the jaw 43 in clamping or open position and for moving the jaw from one position to the other. As embodied, the jaw member 43 is formed at one end with an enlarged head 50 which is provided with an awrture 5| into which an operating bar may be inserted to rotate the jaw. Adjacent to the aperture 5| and formed as a part of the head is a boss 52 which cooperated with a long, round nosed arcuate spring 54 fastened at one end to the cylinder body by screws 56. The rounded end 51 of this spring is adapted to bear against either side of boss 52 and securely holds the jaw member 43 in either of its positions.

Ratchet means are provided for securing the reel rod 33 in tensioning position and a ratchet wheel 60 is keyed to the outer end of rod end 36, this ratchet cooperating with the double pawls 62 which are pressed against the ratchet teeth by springs 64. Pawls 62 are formed with extensions 65 by which they may be lifted to release the tension on the blanket when the blanket is to be replaced.

The construction above described for one longitudinal half of the cylinder may be duplicated for the other half, and is generally angularly displaced therefor.

In operation, the ends of the sheets, including makeready sheets, if desired, are first clamped against face 2| by jaw 43, thereby impaling the sheets on pins 25. The sheets are then wrapped around the cylinder and the other end of the blanket 30 is inserted through the slot 40 in reel rod 33. By turning the reel rod the blanket is tightened and securely fastened. Thereafter,

suitable makeready is attached to the blanket, jaw 43 is opened and the free end of sheet 3| is inserted in the jaw to be clamped against face 2| and as jaw 43 is closed, this end is impaled and is .then pulled tight by the outer end of the jaw. Before clamping this free end at the beginning of a run, however, the ends of the sheets 3|] and 3| for the other circumferential half of the cylinder are impaled on their pins 25.

During printing, the blanket 30 may be tightened as necessary by turning the reel rod 33 and the draw sheet 3| may be renewed or the makeready changed without disturbing the blanket.

The invention in its broader aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principles of the invention and without sacrificing its chief advantages.

What I claim is:

1. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity in the cylinder body, said cavity containing means for holding two sheet ends, an

angularly movable jaw for clamping a third sheet end and moving it relatively to the first two ends and a slotted reel rod for independently drawing a fourth sheet end, said jaw being concentric with reference to the slotted reel rod.

' 2. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity in the cylinder body, said cavity containing pins for holding two sheet ends, an angularly movable jaw for clamping a third sheet end over said pins for drawing it over the first two sheet ends and a reel rod to which a fourth sheet end may be fastened for independently drawing the fourth sheet end, said jaw having its center within the periphery of the reel rod.

3. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity within the cylinder body, ;a jaw jaw being movable to stretch one sheet on the other, a slotted reel rod within the cavity to wind up the end of a sheet to tighten it, a cam secured to said jaw, a circumferentially extending groove near the end of the cylinder, and a leaf spring operating therein on the cam for resiliently moving said jaw.

4. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity within the body of the cylinder, a slotted roller rotatably mounted within said cavity and means for attaching one end of a sheet within said slot, said means including a hollow slotted clamping jaw angularly movable within the cavity and having its center within the periphery of the slotted roller and partially enclosing said roller.

5. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity within the body of the cylinder, means within the cavity for engaging the end of, and stretching, a sheet, a jaw for engaging the end of another sheet, a cam secured to the jaw, a groove in the cylinder, and a circumferentially extending spring secured to said cylinder in said groove for actuating the jaw through the cam.

6. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity within the cylinder body, projecting pins for holding a sheet in said slot, a jaw for pressing a sheet over said pins and holding it firmly on said pins, a cam secured to the jaw, and a circumferentially extending spring secured to said cylinder for actuating the jaw through the cam.

7. A blanket cylinder for printing presses including in combination a rotatable cylinder body having a narrow slot therein opening into an enlarged cavity within the body, a rotatable roller within the cavity to which a sheet end may be attached, a curved member having a jaw extending therefrom and pivotally mounted for clamping movement toward and from one edge of the slot, said roller being partially surrounded by said curved member and said curved member and jaw being movable about said roller.

CURTIS S. CRAFTS.