Sheet-feeding device for printing presses

Claim 2

Sheet feeding apparatus for printing presses including a printing cylinder oN a single revolution shaft having a rotating pregripper drum with gripper means thereon to receive sheets from a feeding table and transfer them, the improvement of drive means for rotating the pregripper drum comprising, a five-part Maltese cross transmission having radially extending slot openings between walls defining the parts and a cooperating rotating driving plate for driving the Maltese cross, said driving plate having three drive rolls mounted thereon circumferentially equally spaced for rotating the Maltese cross, said walls of the Maltese cross defining the slots extending in circular arc curves in opposite directions and adjacent slot outer ends act to temporarily block the Maltese cross between two of said driving rolls received therein, said Maltese cross having drive means thereon cooperating with drive means on the pregripper drum for periodically rotating the pregripper drum, and means for rotating said driving plate whereby it and its driving rolls rotate at one-third speed of said single revolution shaft, said temporary blocking of the Maltese cross causing a relatively short resting time of the rotary pregripper and the driving by the Maltese cross causing the rotary pregripper to have a relatively long acceleration angle.

Claim 3

Sheet feeding apparatus according to claim 1 wherein said gripper means on the pregripper drum are reversal grippers.

Claim 4

Sheet feeding apparatus according to claim 2 wherein said sheet feeding table has front lays having means operating them from below the same and said rotating pregripper drum is positioned below said feeding table.

Claim 5

Sheet feeding apparatus according to claim 3 wherein said feeding table has covered front lay control means.

Claim 6

Sheet feeding apparatus according to claim 4 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 7

Sheet feeding apparatus according to claim 3 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 8

Sheet feeding apparatus according to claim 2 wherein said feeding table has covered front lay control means.

Claim 9

Sheet feeding apparatus according to claim 7 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 10

Sheet feeding apparatus according to claim 2 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 11

Sheet feeding apparatus according to claim 1 wherein said sheet feeding table has front lays having means operating them from below the same and said rotating pregripper drum is positioned below said feeding table.

Claim 12

Sheet feeding apparatus according to claim 10 wherein said feeding table has covered front lay control means.

Claim 13

Sheet feeding apparatus according to claim 11 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 14

Sheet feeding apparatus according to claim 10 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 15

Sheet feeding apparatus according to claim 1 wherein said feeding table has covered front lay control means.

Claim 16

Sheet feeding apparatus according to claim 14 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means on the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 17

Sheet feeding apparatus according to claim 1 wherein said pregripper drum has two rows of gripper means and wherein said drive means on the pregripper drum and the drive means of the Maltese cross transmission have a drive means ratio of 2.5 to 1.

Claim 18

Sheet feeding apparatus according to claim 1 wherein said gripper means on the pregripper drum are dip grippers.

Claim 19

Sheet feeding apparatus according to claim 1 wherein said gripper means on the pregripper drum are suction grippers.

Claim 20

Sheet feeding apparatus for printing presses including a printing cylinder on a single revolution shaft having rotating pregripper or stop drum with gripper means thereon to receive sheets from a feeding table and transfer them, the improvement of drive means for rotating the pregripper or stop drum comprising, a five-part Maltese cross transmission for driving the pregripper or stop drum and having radially extending slot openings equally spacing said parts thereof and a cooperating rotating driving plate for rotating the Maltese cross, said driving plate having three drive rolls mounted thereon circumferentially equally spaced for rotating the Maltese cross, said Maltese cross having drive means thereon cooperating with driven means on the pregripper or stop drum for periodically rotating the same, said Maltese cross having the outer opposite ends of the walls defining said radial slots extending in circular arc curves in opposite directions and adjacent slot outer ends act to temporarily block the Maltese cross between two of said driving rolls received therein, and means for rotating said drive plate whereby the temporary blocking of the Maltese cross drive causes a relatively short resting time of the rotary pregripper and the driving by the Maltese cross causes the rotary pregripper to have a relatively long acceleration angle.

Claim 21

Sheet feeding apparatus for printing presses including a printing cylinder on a single revolution shaft having rotating pregripper or stop drum with gripper means thereon to receive sheets from a feeding table and transfer them, the improvement of drive means for rotating the pregripper or stop drum comprising, a five-part Maltese cross transmission for driving the pregripper or stop drum and having radially extending slot openings equally spacing said parts thereof and a cooperating rotating driving plate for rotating the Maltese cross, said driving plate having three drive rolls mounted thereon circumferentially equally spaced for rotating the Maltese cross, said Maltese cross having drive means thereon cooperating with driven means on the pregripper or stop drum for periodically rotating the same, said Maltese cross having the outer opposite ends of the walls defining said radial slots extending in circular arc curves in opposite directions and adjacent slot outer ends act to temporarily block the Maltese cross between two of said driving rolls received therein, and means for rotating said drive plate whereby the temporary blocking of the Maltese cross drive causes a relatively short resting time of the rotary pregripper and the driving by the Maltese cross causes the rotary pregripper to have a relatively long acceleration angle.