US1257538A - Blanket-cylinder. - Google Patents

Description

m1. & W. 0. SCOTT.

BLANKET CYLINDER.

APPLICATION HLED JULY 21. I914.

Patented Feb. 26, mm.

2 SHEETS-SHEET I.

WITNESSES A TTOR/I/EV,

D. Jl. & W. C. SCOTT.

BLANKET CYLINDER.

APPLICATION FILED JULY 21.1914.

edl 1M). 26, 1918. 2 SHEETS-SHEET 2- lNl/E/VTORS,

ATTOR/VEV B WaZfiaWU 500%.

* I MIA/5820M DAVID JOHNSCOTT AND WALTER CHARLES SCOTT, 0F PIIAINFIELD, NEW JERSEY, ASSIGNORS T0 ISABELLA SCOTT AND DAVID J. SCOTT, EXEGUTORS 0F WALTER SCOTT, LATE 0F PLAINFIELD, NEW JERSEY.

BLANKET-CYLINDER.

Specification of Letters Patent.

Patented Feb 2%, 191.,

Application filed Jul? 21, 1914:. Serial No. 852,155.

To all whom it may concern Be it known that we, DAVID J. ScoTT and WALTER C. ScoTT, citizens of the United States, and residents of Plainfield, in the county of Union and State of New Jersey, have invented certain new and useful llmprovements in Blanket-Cylinders, of which the following is a specification.

As is well known in the art, offset printing is produced by printing from a form on a resilient transfer surface (usually a cy linder carrying a rubber blanket) and thls blanket in turn prints on the paper, metal, glass or wood, etc. While a slightly yielding surface is required in order to receive and transmit perfect impressions, it is nevertheless quite important that this surface be a reasonably firm one, and to accomplish this result, a comparatively thin rubber blanket, consisting of several plies of canvas, rubber-treated and vulcanized together and with a rubber surface, is stretched over the transfer surface of the cylinder. lit is important that this blanket be drawn very tight in order to prevent excessive working of the surface while it receives and delivers the impression, because excessive working would wear away the design and cause blurs and discrepancies in the register. Also, as it is difficult to produce rubber blankets that are perfectly uniform in thickness, it is important that the clamping arrangement be such that the blanket can be taken off to underlay it and put on packing'with the utmost despatch in order to reduce the time lost in making the press ready to the minimum.

In the regular offset presses, Where the printing surface or transfer surface extends only partially around the blanket cylinder, the location and arrangement of the blanket clamps is a comparatively easy matter, but in adapting offset presses for periodical and newspaper work, where comparatively narrow margins are the rule, and the printed ing; to have this blanket clamping system capable of being worked rapidly so as to minimize lost time, and also have it of a substantial character, enabling the proper tension to be given to the blanket to prevent the excessive working of the surface while Fig. 2 is a detail View of one ofthe adjustable ratchets.

Figs. 3, 4 and 5 are sectional views through one of the reel rods showing the stages of operation in tightening the blanket on the cylinder.

Fig. 6 is a sectional view substantially on the line 66 of Fig. 1.

Similar characters of reference indicate corresponding parts in the different views.

1 indicates a blanket or other cylinder having a continuous supporting surface 16 v with the exception of the opening 2, which opening is partly closed to form a relatively narrow slot by the overhanging ledges 17 which form continuations of the supporting surface 16. 3 is the flexible member here shownas a rubber blanket each end of which is preferably provided with reinforcing means consisting of bars 4: and 5 coming on opposite sides of the blanket and secured thereto in any improved manner, as by means of the bolts 6. The bar 4 is provided with a downwardly projecting extension 8 and has at its upper end a beveled edge 7. 9 indicates the reel rods which, as shown, are located underneath the overhanging ledges 17 of the cylindrical supporting surface 16 opposite sides of the plane of the slot. Each of these reel rods is provided with a longitudinally extending groove 11 adapted to receive the projection 8. The outer wall 12 of this groove 11 constitutes a stop against which the extension 8 is adapted to hear when the reinforced end of the blanket is clamped to the reel rod. 10 is an abutment member on the reel rod for preventing the downwardly projecting extension 8 from being withdrawn out of the longitudinally extending groove 11 when the reel rod is turned, and serves thereafter to tighten the blanket in position on the supporting surface of the cylinder. The width of the opening 2 in the blanket cylinder should be sufiicient to permit two thicknesses of the blanket to pass through, plus the thickness of the reinforcing means, this opening being sufliciently wide to allow the ordinary operators fingers to start the reinforcing means of the blanket into the longitudinal groove 8. i

The outer end of the reel rod 9 is milled square, as at 13, so as to form a wrench head. Mounted on this square portion 13 is a ratchet 14:, the pawl 15 mounted on the end frame .of the cylinder serving to prevent the backward rotation of the reel rod after the blanket has been tightened.

Inasmuch .as it is necessary that the two reel rods be close together in order to be in a position to be reached by the operators fingers when inserted through the narrow opening 2, and in order not to reduce the size of the ratchets 14 below that of substantial proportions, the said ratchet 14 is mutilated and has teeth only on a portion of its circumference. By this means, and as shown in 'Fig. 1, it is possible to bring the.

reel rods very closely together since the mutilated portions of the two ratchets are brought opposite to each other. In order to permit these ratchets to be adjusted to always bring the teeth thereof into operative position wlth the pawls 15, the inside of the ratchets are squared out, as shown at 18, so that the ratchet may be removed from the squared end 13 and replaced after having been turned 45. This adjustment is especially desirable on account of varying length of the blankets.

The reinforcing members 4: and 5 are secured to the ends of the blanket before it is inserted Within the cylinder. Thereafter the blanket is stretched over the supporting surface of the cylinder, andthe ends thereof dropped through the opening 2 of the cylinder. At this time, the rotatable members are in such position that the provisions for engaging the reinforcing means 5 and 6 are facing each other on opposite sides of the plane of the slot so that when the pendent free ends of the flexible member 3 are slightly inclined from a line passing through the plane of the slot, the projections 8 will enter the grooves 11 in unlocked position. The reel rods are now turned first to effect an inteilocked connection with the reinforc ing means, as shown in Fig. 5, said rotation continuing thereafter until the blanket is sufiiciently tightened upon the cylinder and the pawls 15 are dropped into the ratchets 14 in order to retain the reel rods in their adjusted position. When it is desired to remove the blanket it is only necessary to release the ratchets and pawls and to rotate the reel rods in a direction opposite to that indicated by the arrows when the reinforeing means will automatically tumble out of the grooves 11 in the reel rods.

By the foregoing means it will be seen that a very substantial construction is obtained within a small compass, so that while a small opening in the cylinder, producing a narrow margin only, is provided, the clamping means are amply sufiicient to insure proper straining of the blanket or other flexible member on the cylinder to give a perfect impression.

What is claimed, is:

1. A sheet carrying cylinder comprising a cylindrical supporting member having a relatively large opening terminating at the cylindrical surface of said member in a relatively narrow slot so as to provide overhanging ledges over the opening, a flexible sheet extending over said cylindrical surface and having its free ends projecting through said slot into said opening, rigid reinforcing means on the free ends of said flexible sheet, and two rotatable members located within said opening under said ledges on opposite sides of the plane of the slot, said members having provisions which, when facing each other on opposite sides of the plane of the slot, are adapted to receive the rigid reinforcing means in unlocked position when the pendent free members are inclined slightly, from a line passing through the plane of the slot, in opposite directions with respect to each other, said members acting, when rotated, first to elfeet an interlocked connection with the reinforcing means and thereafter to tighten the flexible sheet over the cylindrical surface.

2. A printing machine cylinder comprising: a cylindrical supporting member having an opening in its surface, a flexible member stretched over the said supporting member and having its ends projecting into said opening, two reel rods located in said opening, a mutilated ratchet on each reel rod, pawls for engaging with the unmut-ilated portions of the ratchet, and means for adjusting said ratchets to bring the mutilated portions thereof adjacent to each other.

Signed at Plainfield, in the county of Union and State of New Jersey this 18th day of July, A. D. 1914.

DAVID JOHN SCOTT. WALTER CHARLES SCOTT. Witnesses:

CARL E. DRANGE, JACOB V. CoLEs.

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