US2693357A - Front registry mechanism for printing machines - Google Patents

Description

Nov. 2, 1954 w w. DAVIDSON FRONT REGISTRY MECHANISM FOR PRINTING MACHINES 2 Sheets-Sheet l Filed Aug. 2, 1952 drrae/vex Nov. 2, 1954 w. w. DAVIDSON 2,693,357

FRONT REGISTRY MECHANISM FOR PRINTING MACHINES Filed Aug. 2, 1952 2 Sheets-Sheet 2 W L [UmjNVZJTQR drizzle/var United States PatentO FRONT REGISTRY MECHANISM FOR PRINTING MACHINES William Ward Davidson, New Yorlr N. Y.', assignor to Davids-on Corporation, a corporation of Illinois Application August 2, 1952,.S'erial No. 302,375

3 Claims.- (Cl. 271-53) This invention relates to rotary printing presses: of either the direct or offset type, and more particularly, to sheet feeding arrangements for machines of this general organization wherein a sheet, fed'either by. hand or automatic means, is advanced to aseries of registering stops, which stops are removed at a predetermined time in the machinecycle and the sheet fed to the printing cylinders.

In such machines, it is customarywfor thel sheets'to be presented between. the upperand lowerfeed rollers and against the stops at a. time when; thenpper roller is raised in relation. to the lowerroller, andiat the proper time in the machine cycle, thenpper rolleris adapted to be dropped into frictional feeding contact with the sheet as the stops are lowered to permit the forward advance of the sheet to moving grippers which carry the sheet to the cylinders to be printed. The purpose of the reciprocatory movement of the upper feed roller toward and away from the lower power driven roller is to facilitate the insertion of the sheet between the roller and to allow for any sideways or transverse movement of the sheet to insure the lateral alignment thereof. In these machines, of course, it is necessary to feed the paper to the stops and to properly souare otf the front edge of the sheet against the stops while the rollers are so separated.

The present invention provides anew and improved feeding system wherein upper feed rollers are permitted, even before presentation of the sheet thereto, to idle in light frictional contact with a lower feed roller, either bv their own wei ht or under light spring pressure. When a sheet is fed therebetween. the rollers serve to gentlv advance the front or leading edge of the-sheet to the paper stops and then, if necessarv, to pivotallv adiust the sheet to square off the leading ed e finsh a inst the sto s. The friction l contact that he idler rollers make with the lowerroller, althou h sufficient to translate the paper and to souare off thezleadingedge a ainst the stops, is li ht enou h to prevent anv'buckling of the sheet even in feeding thin sheets. such as onion skin. and once squared off; the idler rol ers make only slipping contact with the: sheep untiladditional feeding pressure is applied to them and the paper stops are lowered to advance the sheet to the grippers.

' The present invention is particularly applicable to machines where lateral alignment or registration. of a sheet is achieved by means other'than last minute lateral movement of the paper, and is especially adapted to hand fed machines or machines where the sheets are individually fed to the rollers between sidewalls or guides which take care of lateral alignment.

One of the distinct advantages offered by the present invention is that the individual sheet need be fed only to the bite between the rollers, rather than beyond the rollers to the paper stops, and the feed rollers, in turn, serve not only to advance the sheet to the paper stops, but to automatically square otf the leading edge of the sheet against the stops as well. This feature is a very decided advantage in machines which are hand fed in that it enables the operator to devote his full attention and concentration to presenting the sheets to the rollers and leaves him free to forget about the proper registration of the sheet against the stops.

The above and other features of the present invention will be more fully brought out in the specification which follows and the accompanying drawings.

2,693,357 Patented Nov. 2, 1954 .Referring to theldrawings: Fig. '1 is a side elevation of atprinting machine equipped with the present invention.

Fig. 2 is a perspective view of the mechanism shown in Fig. l, but with. the parts in different operative position. Fig. 3 is a view similar to Fig. 1, but illustrating the application of pressure to theidler rollers and the lowering of. the stops.

Fig. 4 is a top plan viewv of the feed roll mechanism.

Fig. 5 is a detailed perspective view of one of the upperfeed rollers in contact with the lower roller.

The present invention is shown and described in connection with and as applied to a duplicating machine of the general organization disclosed in United States Patent No. 2,387,750 to W. W. Davidson. The machine comprises generally two cylinders 1 and 2 arranged in tangential relationship, the formerbeing twice the size of the latter. The machine is capable of doing both direct and offset printing, and for a complete understanding of its operation, reference can be hadto the above patent. For present purposes, it suffices to say that when employed in direct printing the large cylinder 1 carries type which prints directly onto the paper passing between the cylinders, the small cylinder under such circumstances acting only as .an impression cylinder against which the paper is printed' When used for offset printing, however, the small cylinder acts as a blanket, receiving the ink impressions'tfrom a printing plate segment attached to the large cylinder and thereupon printing directly onto the paper against a platen segmentof the large cylinder. .The cylinders 1, 2 are rotatably mounted on shafts 3,v 4, respectively, mounted inside frames A of the machine.

According to the present sheet feeding arrangement, the sheets x are individually fed, either mechanically or by hand, onto a table 5 and into the bite between a constantly rotating lower roller 6 and a plurality of upper idler rollers 7 which advance the leading edge of the sheet to a series of stop fingers 8. The upper idler rollers are normally adapted to be held in very light frictional contact with the lower roller in order to pick up a sheet fed thereto and presented therebetween and advance the leading edgeto the stops 8 and, furthermore, to properly register or square off the leading edge of the sheet against the stops. The frictional contact made by the upper idler rollers 7, however, is so slight L that oncethe leading edgeof the sheet has beencarried 1 the effect of buckling the sheet.

to and squared off against the paper stops, the rollers have no further effect on the sheet, althoughthev lower power driven roller 6 continuesto rotate and make slipping contact with the sheet so positioned without having At the appropriate time in the machine cycle of operation, the sheet grippers 9, which, as usual, are mounted on a shaft 10 extending between and carried by a pair of endless chains 11' (see Figr 2), travel around to the sheet receiving position and are caused to open by the enga ement of a roller 12 carried at the endof the shaft 10 with a fixedcam 13 mounted to the side frame of the machine. More or less simultaneously, the: stop fingers 8 are lowered and pressure isapplied to the upper idler rollers 7, forcing them against the lower roller 6 and thereby increasing the strength of the bite in order to advance the leading edge of the sheet into the open grippers. The grippers 9 thereupon clamp the leading edge of the sheet and carry it between the printing cylinders and thereafter to the usual delivery or discharge receptacle.

The general scheme of operation of the present invention having been explained, it is now ap ropriate to go into the mechanical details thereof. The constantly driven roller 6 is supported on a rotatable shaft 15 journaled in bearings in the side walls A. The roller 6 is preferably metal and has a rou h or knurled finish. The upper idler rollers 7 are rotatablv mounted on arms 16 fixedly mounted to a rock shaft 17 supported in the side frames of the machine. The rollers 7 are preferably of rubber and normally idle in light frictional contact against the lower roller 6. As best shown in Fig. 2, the rock shaft 17 is provided at one end with a hook 17a adapted to be acted upon by a very light adjustable spring 19.

The finger stops 8 are spaced at intervals on a rock shaft 18, which shaft is also rotatably mounted in the side frames of the machine, and, in their operative raised position, the stops project through slots in the forward end of the table in position to engage the leading edge of a sheet fed between the rollers 6, '7. As explained above, a sheet need be fed only as far as and presented to the rollers 6, 7, and, from that point on, the sheet is under the control of the machine cycle. The sheet is first gently advanced in the bite of the rollers to the finger stops, and then, if necessary, pivotally adjusted or squared off against the stops. However, once the sheet is in feeding position, it is held there until the appropriate time in the machine cycle, even though the roller 6 continues to rotate, the said rollers, as previously mentioned, making merely slipping contact with the sheet without buckling it against the stops.

When the grippers 9 reach the sheet receiving position, the stops are lowered and downward pressure is applied to the idler rollers 7. These operations are controlled by a pair of cams 20, 21 (see especially Fig. 2) adjustably mounted for proper timing on the shaft 3. A pair of centrally pivoted levers 22, 23 having rollers 24, 25 at their upper ends are supported from one of the side frames of the machine, the rollers being maintained in engagement with the contour of the cams by springs 26, 27.

More or less vertically disposed arms 28 are loosely and pivotally positioned on the shaft 17, each adjacent to one of the idler carrying arms 16 (see Fig. 5), and the arms 28 are provided with forwardly projecting yielding members or leaf springs 29 which engage the arms 16, so that when the arms 28 are rocked about the shaft 17 in a counterclockwise direction (as viewed on the drawings), a yielding pressure will be applied to the idler rollers 7, forcing them against the lower roller 6. This counterclockwise rotation is controlled by a raised portion of the cam 20 (see Fig. 1) through a rod 30 pivotally connected at one end to the lower end of the lever 22 and at the other end bent in such a manner to pass through each of the rock arms 28.

As best shown in Figs. 2 and 3, the operation of the finger stop 8 is controlled from the cam 21 through a rod 31 loosely connected at one end to the lower end of the lever 23 and at the other to an arm 32 attached to the shaft 18 supporting the stops. The raised portion of the cam 21 pivotally rotates the shaft 18 to lower the finger stop 8 below the surface of the table 5. The lowering of the stops 8 and the application of pressure to the idler rollers 7 is more or less simultaneous, and in timed relation to the travel of the grippers 9, so that the sheet will be immediately accelerated in that direction and the leading edge of the sheet presented to the open moving grippers.

The above described sheet feeding arrangement is suitable to accommodate sheets of a wide variety of thicknesses without adjustment. In feeding very thin sheets, such as onion skin, the pressure of the spring 19 is adjusted to be nil, or practically nil, the weight of the idler rollers 7 by themselves producingsufiicient frictional engagement with the sheets. In feeding heavier and thicker sheets, however, a very slight spring pressure is desirable, and the spring 19 may be adjusted accordingly.

The invention has been shown and described in its preferred form and obviously many modifications and variations may be made therein without departing from the spirit of the invention. It is to be understood, therefore, that the invention is not to be limited to any specific form or embodiment, except insofar as such limitations are specified in the appended claims.

The invention having been described, the following claims are made:

1. Sheet feeding means for a printing machine comprising a feed table, stops to engage the forward edge of the sheet to be fed while the sheet is traveling across said table, a constantly rotating feed roller, a roller adapted normally to idle in light spring controlled frictional engagement with the constantly rotating roller, said idler roller cooperating with the constantly rotating roller to advance a sheet presented between the rollers to the stops and to square off the leading edge of the sheet against the stops Without buckling the sheet, power controlled means to lower the stops to inoperative position, and power controlled means operable in timed relation to the lowering of the stops to apply pressure to the idler roller against the sheet in order to present the sheet to the printing mechanism.

2. Sheet feeding means for a printing machine comprising a feed table, stops which in their operative position engage the leading edge of a sheet traveling across the feed table, a constantly rotating feed roller, a plurality of idler rollers adapted to normally make light frictional contact with the constantly rotating feed roller, an adjustable spring to maintain a very light controlled pressure on the idler rollers, said idler rollers and feed roller cooperating to advance a sheet presented between them to the stops and to square off the leading edge thereof against the stops Without buckling of the sheet, cam controlled means to lower the stops to inoperative position, and cam controlled means operable in the timed relation to the lowering of the stops to transmit through a yielding connection feeding pressure to the idler rollers.

3. Sheet feeding means for a printing machine comprising a feed table, stops which in their operative po sition engage the leading edge of a sheet traveling across the feed table, a constantly rotating feed roller, a plurality of idler rollers adapted normally to make light frictional contact with the constantly rotating feed roller, a rock shaft upon which the idler rollers are mounted, an adjustable spring to maintain a very light controlled pressure in the idler rollers, said idler rollers and feed rollers cooperating to advance a sheet presented between them to the stops and to square off the leading edge thereof against the stops without buckling the sheet, a yieldable member loosely mounted on the rock shaft, said yieldable member being inoperative during the registrationof the sheet by the idler rollers, cam controlled meansto lower the stops, and cam controlled means op- UNITED STATES PATENTS Number Name Date 752,383 Dexter Feb. 16, 1904 1,683,635 Thatcher Sept. 11, 1928 2,428,769

Bobst Oct. 14, 1947

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