US1984588A - Sheet feeding apparatus - Google Patents

Description

Dec. 18, 1934.

M. LIEBUSCH 1,984,588

' SHEET FEEDING APPARATUS Filed Sept. 6, 1952 s SheetsSheet 1 "By I y 18, 1934. usc 1,984,588

SHEET FEEDING APPARATUS Filed Sept. 6, 1932 3 Sheets-Sheet 2 [was/v70? SHEET FEEDING APPARATUS- Filed Sept. 6, 1932 3 Sheets-Sheet 3 I 5 By Patented Dec. 18, 1934 PATENT OFFICE 1,984,588 SHEET FEEDING APPARATUS Max Liebusch, Kotzschenbroda, Germany Application September 6, 1932, Serial No. 631,918 In Germany April 19, 1932 10 Claims. (01. 271-53) In machines for printing separate sheets it is necessary for each sheet to be levelled to obtain accurate register before it is passed to the impression cylinder. Thus every sheet introduced onto the laying-on table must be arrested by the registering stops and there brought into correct position before it is allowed to proceed on its way. Naturally the fresh sheet can only gain access to the registering stops when the rear end of the preceding sheet has moved'completely out of range of the said stops. As the time available for setting the sheets is extremely short, it is of great advantage to increase this time as much as possible. As, on the other hand, the disengagement of the registering stops by the preceding sheet is dependent upon the essential condition that the sheets must be moved at the point of their transference to the impression cylinder at thespeed of printing, it follows that the period available for. setting the sheet to the registering stops on the laying-on table is itself de pendent upon the speed of printing. Since however, as already pointed out, it is of great advantage to increase the period for setting the sheet whilst retaining the same speed of printing, many attempts have been made in this direction and practicable apparatus constructed for this purpose, all based on the idea of accelerating the speed of the rear end ofthe sheet in relation to that of its forward end, whose speedof advancement is governed by the speed of printing. In the arrangements hitherto known this was effected by moving the sheet transversely out of its normal path after its forward end had left the laying on stops, thereby, to a certain extent, lengthening the path of the rear end of the sheet in comparison with that of the forward end. Even though these arrangements were per se suflicient for their purpose, they had,

nevertheless, the defect that the sheet was removed from its smooth and even disposition on a secure and rigid base and to a certain extent suspended in the air, so that there was a possibility of mishap.

The object in view could be far better obtained if the sheet could be moved out of the range of the registering stops without it being necessary to remove it from its normal path of movement, which cannot always be done without the application of a certain amount of force.

The object of the present invention is to embody this method of solving the problem and consists in inserting in the path of the sheet to the feeding cylinder'between the laying-on table acceleration of movement is obtained by a uniformly accelerated rotation of the feeding cylinder in combination with a lag or retardation of the sheet holding grippers as the sheet is transferred to the impression cylinder.

As will be evident, by these means the rear end of the sheet can be withdrawn from the range of the registering stops without it being necessary to move the sheet from its normal path or lift it from its base. The apparatus for carrying out the method according to the invention may be of various constructions, according as the first, second or third method is employed.

For carrying out the first form of the method according to the invention, the grippers provided on the uniformly rotating and non-accelerated feeding cylinder are mounted to oscillate about the axis of the said cylinder and are actuated by special means in such manner that after gripping the sheet they carry out a movement in the direction of feed in addition to the move- .ment of the cylinder and before the transference of the sheet to the impression cylinder they are moved in opposite direction relative to the feeding cylinder.

For the second embodiment of the invention the device is so constructed that the feeding cylinder is controlled by separate mechanism which first accelerates its speed of rotation after the sheet has been gripped, and then slows it down after the sheet has left the laying-on table, so that the sheet is passed to the impression cylinder at the speed of printing.

In the final embodiment of the process according to the invention, the grippers are mounted on the uniformly accelerated feed cylinder to pivot about the axis thereof and are so controlled that, as they approach the impression cylinder, they carry out a retrograde movement relative to the movement of the cylinder.

If in carrying out the process the feeding cylinder is caused to run at accelerated speed, it is preferable to make the diameter of this cylinder greater than that of the impression cylinder. In all cases it is desirable to lengthen as far as possible the path of the sheet between the laying-on table and the impression cylinder. This object can be simply attained according to the invention by disposing the laying-on table at a higher altitude than usual.

Reference will now be made to the accome panying drawings which illustrate the-three constructions of the device for carrying out the process according to the invention. I

Figures 1, 2 and 3 illustratediagrammatically the first form of construction,

Figures 4, 5 and 6 illustrate the second form,

and Figures '7, 8 and 9 illustrate the third form.

Referring first to Figs. 1-3, asheet 5 is transferred to the grippers 1 of the sheet feeding cylinder 2 by the gripping members 3 of the oscillating pivoted preliminary grippers 4, which grip the sheet on the laying-on table 6 after it has been levelled at the stops 1 to produce accurate-register. The preliminary gripper arms 4 are connected by a link 21 to a roller lever 20.

which is actuated by an eccentric 19 whereby the preliminary grippers 3 are properly operated. The eccentric 19 is of such a shape that the grippers 3 stop at the table 6 to receive one end of a sheet 5 and then'the speed thereof is progressively increased until it is equal to the speed of the feeding grippers 1, which speed, in

' this instance, is the same as that of the cylinder 2 and the printing speed, so that the sheet may be readily transferred to the feeding grippers 1. By the rotation of the feeding cylinder 2 the sheet 5 would be withdrawn from the table 6 at the speed of rotation of the said feeding cylinder, and not until then would the stops 7 be able to, receive a fresh sheet. According to the invention, however, the shaft 8 of the grippers 1 is not mounted for fixed movement with the cylinder, but is carried in similar manner to the preliminary grippers 3 and 4 by levers 9 mounted to rotate about the axis of the cylinder. The levers 9 of the grippers 1 are connected by a link 24 to a roller lever 23 which is actuated by a cam 22 whereby the grippers 1 are properly operated. It is thus possible by the proper shaping of the cam 22 to cause the whole gripper device 1 8 and 9 to move separately from and relative to the cylinder, so that during the rotation of the cylinder 2 from the position shown in Fig. 1 to the position shown in Fig. 2, the feeding gripper device 1, 8, 9 can carry out a separate faster or leading movement in addition to the movement caused by the cylinder, whereby the whole sheet 5, and not only its rear portion, is withdrawn from the laying-on table at accelerated speed, so that more time is available for setting the following sheet. As the cylinder 2 continues to rotate, the cam 22 causes the gripper arrangei ment 1, 8, 9 to carry out a separate retarded or lagging movement, so that the forward edge" 10 of the cylinder jacket or case gradually overtakes the grippers and comes into register therewith shortly before the sheet is transferred by the grippers 1 to thegrippers 11 of the impression cylinder 12. During the transference of the sheet (Fig. 3), the gripper arrangement 1, 8, 9 therefore moves at the same speed as the cylinders 2 and 12, so that the sheet can be readily transferred from one cylinder to the other.

A further embodiment of the same inventive idea is illustrated in Figs. 4 to 6. In this case 13 and owing to the greater diameter of the cylinder 13, the peripheral speed thereof is greater than that of the impression cylinder 12 so that the sheet 5 is withdrawn from the table 6 at a speed greater than that of printing. The preliminary gripper device 3, 4 is operated by mechanismsimilar to that shown in Fig. 1 and from the'position in which it receives a sheet from the table 6, the speed thereof is caused to graduallyincrease until it is equal to the peripheral speed of the cylinder 13 at the point where the grippers 14 thereof receive the sheet from the preliminary gripper device. After the sheet has been withdrawn from the range of the stops 7, as shown in Fig. 5, the speed of rotation of the cylinder 13 is causedto fall owing to an automatic'speed changing mechanism 15 which comprises a pair of elliptical gears which are arranged so that each of the cylinders lz; and 13 make one complete revolution in the same time, but these gears are related so that shortly before the transference of the sheet from the grippers 14 to the grippers 11 of the impression cylinder 12, the cylinder 13 is caused to assume the same peripheral speed as the impression cylinder 12 so that, as shown in Fig. 6, the sheet may be readily transferred to the cylinder 12. Later the cylinder 13 again increases in peripheral speed so that it can withdraw the fresh sheet taken up by the grippers 3, 4 at increased speed.

Figs. 7 to 9 illustrate a form of construction in which the accelerated removal of the sheet from the laying-on table is again effected by means of an enlarged feeding cylinder 13. In this case however the cylinder 13 rotates at a uniform peripheral speed which is greater than that of the impression cylinder 12, so that the intermediate speed varying mechanism 15 employed in the construction according to Fig. 4 is not required. The grippers 16 of the cylinder 13 are not fixed to the cylinder as in Fig. 4, but are mounted on levers 17 rotatable about the axis of the feeding cylinder as in Fig. 1, and are capable of carrying out a separate movement relative to the cylinder. After the grippers 16 have taken the sheet over from the oscillating preliminary grippers 3, 4, as shown in Fig. '7, they remove it from the table 6 at a greater speed than that of cylinder 12 and the printing speed. The preliminary gripper device 3, 4 is actuated in a manner similar to that shown in Fig. 1 and the speed of the grippers 3 is increased so that it is equal to the speed of grippers 16 at the time ofthe transfer of a sheet thereto. As the sheet 5 held by the grippers 16 is drawn by the forward movement of the lever 17 forwardly over the surface of the feeding cylinder 13, this surface is provided with a number of brackets 18 for supporting the sheet, as shown in Figs. 1-3. When the end of the sheet has passed out of the range of the stops '7 (Fig. 8), the movement of the gripper arrangement 16, 17 is retarded, this lagging being so regulated that in accordance with the rotation of the cylinder 13 it enables the sheet to be transferred to the cylinder 12 at normal printing speed. The retardation of the gripper device 16, 17 is accomplished by mechanism similar to that shown in Fig. 2 and is so reguwithdrawing the entire sheet from said prede-- termined position at a speed in excess of the printing speed, decreasing the speed of the entire sheet after it has rapidly cleared said predetermined position to the constant speed of said printing member and presenting said sheet to said printing member.

2. The method of feeding sheets to a printing member operating at a constant speed, which consists in arranging a sheet in a predetermined position, seizing the front end of the sheet and drawing it toward the printing member, increasing the speed of the entire sheet so that it rapidly clears said predetermined position, thereafter decreasing the speed of the entire sheet to the constant speed of said printing member, then presenting said sheet to said member, and arranging another sheet in said predetermined position.

3. A sheet feeding apparatus for delivering sheets to a member travelling at a constant speed, comprising a table, means for locating a sheet on said table, and feeding means for gripping the front edge of a sheet from said table and withdrawing the entire sheet from said table at a speed greater than the speed of said member and thereafter delivering the sheet to. said member at substantially the same speed as that of said member whereby the sheet is rapidly'removed from said table to afford a long time for the locating of another sheet thereon.

4. A sheet feeding apparatus for delivering sheets to a printing member travelling at a constant speed, comprising a table, means for locating a sheet on said table, feeding means including gripper devices for gripping the front edge of a sheet from said table and delivering it to said printing member, and means for driving at least one of said devices at a speed greater than the constant speed of said'printing member for removing the entire sheet from said table at a speed in excess of the printing speed and thereafter at a retarded speed substantially edge of said sheet from said preliminary gripe ping device, means for rotating said .feeding gripper at 'a speed greater than the speed of said feeding roll during a portion of its travel and then reducing the speed thereof belowthe speed of said printing roll and a gripper on said printing roll for receiving the front edge ofthe sheet from said feeding gripper when the speed thereof is substantialLv equal to the speed of said printing roll.

6. A sheet feeding apparatus for delivering sheets to a printing roll travelling at a constant speed, comprising a table, means for locating a sheet on said table, a preliminary gripping device for withdrawing the front edge of a sheet from said table, a feeding cylinder having 'means for receiving the front edge of the sheet from said preliminary gripping device, said feeding cylinder being of a diameter greater than that of said printing roll, and mechanism for rotating said feeding cylinder at a greater peripheral speed than that of said printing roll during a portion of its travel and for reducing the peripheral speed thereof before transferring the sheet to said printing roll to the peripheral speed of the printing roll whereby to properly transfer the sheet from said feeding cylinder to said printing roll.

7. A sheet feeding apparatus for delivering sheets to a printing roll travelling at a constant speed, comprising a table, means for 10- cating a sheet on said table, a preliminary gripping device for withdrawing the front edge of said sheet from said table, a feeding cylinder of larger diameter than that of said printing ,roll at the time of the transference of the sheet to said printing roll, and a gripper on said printing roll to receive the front edge of said sheet.

8. A sheet feeding apparatus for delivering sheets to a printing roll traveling at a constant speed, comprising a table, means for locating a sheet on said table, a preliminary gripping device for withdrawing the front edge of a sheet from said table, a feeding cylinder mounted on a shaft for rotation at the same speed as that of said printing roll, a feeding gripper mounted on said shaft for movement independent of the movement of said feeding cylinder and adapted to receive the front edge of said sheet from said preliminary gripping device, means for rotating said feeding gripper at a speed greater than that of said feeding cylinder until the entire sheet has been withdrawn thereby from said table and for then reducing the speed thereof below that of said feeding cylinder, means on said feeding cylinder for engaging said feeding gripper and urging the same toward said printing roll at the same speed thereof whereby to properly transfer the sheet, and means on said printing roll for receiving the sheet from said feeding gripper.

9. A sheet feeding apparatus for delivering sheets to a printing roll traveling at a constant speed, comprising a table, means for locating a sheet on said table, a preliminary gripping device for withdrawing the front edge of a sheet ripheral speed than that of said printing roll until the entire sheet has been withdrawn thereby from said table and for reducing the peripheral speed thereof until it is equal to the peripheral speed of said printing roll at the time of the transference of the sheet to said printing roll, and means on said printing roll for receiving the sheet from said feeding cylinder.

10. Av sheet feeding apparatus for delivering sheets to a printing roll traveling at a constant speed, comprising a, table, means for locating a sheet on said table, a preliminary gripping device for withdrawing the front edge of a sheet from said table, a 'shaft, a. feeding cylinder mounted on said shaft and having a larger diameter than that of said printing roll and traveling at a constant peripheral speed greater than. that of said printing roll, a feeding gripper mounted on said shaft for movement independent of the movement of said feeding cylinder and adapted to receive the front edge of the sheet from said preliminary gripping device, means for moving said feeding gripper at a speed in excess of that of said feeding cylinder before the reception of the sheet by said feeding gripper and for then moving said feeding gripper at the speed of said feeding cylinder where- \by to withdraw the entire sheet rapidly from said table in excess of the printing speed and finally reducing the speed of said feeding gripper to the speed of said printing roll whereby to properly transfer the sheet thereto, and means on said printing roll for receiving the sheet.

. MAX LIEBUSCH.

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