BRIEF DESCRIPTION OF THE DRAWINGS
A preferred embodiment of the present invention will be elucidated with reference to the drawings, in which:
FIG. 1 shows a gripper device according to the present invention;
FIG. 2 shows a gripper of the gripping device;
FIG. 3 shows a schematic view of the gripper;
FIG. 4A shows the upper and lower arms of the gripper; and
FIG. 4B shows a gripper pad of the gripper.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT
FIG. 1 shows a preferred embodiment of a gripper device 14 having gripper arms 16 with gripper bases 15. A gripper 20 is mounted on each base 15 in such a way to allow grippers 20 to rotate as gripper device 14 rotates. Thus, grippers 20 maintain an upright position 18 as gripper device 14 rotates clockwise.
As a printed product 40 is transported along an escalator tucker 12, escalator tucker 12 lifts printed product 40 up to be gripped by grippers 20. Gripper device 14 is timed with escalator tucker 12 via a controller 80 controlling individually driven servo motors 82, 84, although the escalator tucker 12 could be geared to gripping device 14 as well. Gripper 20 removes printed product 40 from escalator tucker 12 and delivers printed product 40 to delivery conveyor 10. Delivery conveyor 10 transports printed product 40 further along. Escalator tucker 12 may be similar to the signature transport device disclosed in U.S. Patent Application Publication No. 2005/0225023, hereby incorporated by reference herein.
FIG. 2 shows a gripper 20 from gripper device 14. Gripper 20 includes upper arm 22 and lower arm 23 having gripper pads 24, 25 and pivots 26, 27 respectively. One end 28 of upper arm 22 is connected to a coupler link 30, while one end 29 of lower arm 23 is connected to another end of coupler link 30. Coupler link 30 is connected at another end 31 to a spring link 32. Spring link 32 is controlled by the movement of cam follower 72 via links 34 and 36. Link 38 pivotally supports cam follower 72 via a pin 172.
The gripper 20 is spring-loaded in an open position, for example, by a cam spring forcing link 30 downwardly in FIG. 2 by forcing link 38 in a direction D. When cam follower 72 is forced opposite direction D, link 38 moves against the cam spring force rotating about a pivot 138, pushing link 34 via link 36 to counteract the cam spring force and force the entire spring link 32 upwardly. When spring link 32 moves upward, coupler link 30 moves upward and ends 28, 29 are pushed upward. Thus, gripper 20 closes as gripper arms 22, 23 rotate around pivots 26, 27.
FIG. 3 shows a schematic of the actuation of gripper 20. When gripper 20 is closed, (solid lines, high cam dwell) upper arm 22 with gripper pad 24 is contacting lower arm 23 with gripper pad 25. As cam follower 72 follows cam 70 to a low dwell, links 38, 36, via the cam spring, move causing link 34 to move into position 34′. Link 34 actuates spring link 32, by pulling spring link 32 downward into position 32′. Spring link 32 pulls coupler link 30 downward into position 30′ causing upper arm 22 to rotate open around pivot 26 and lower arm 23 to rotate open around pivot 27. Upper arm rotates into position 22′ with gripper pad 24′ while lower arm rotates into position 23′ with gripper pad 25′.
FIG. 4A shows upper arm 22 and lower arm 23. Gripper pads 24, 25 are adjustable and may be covered with a layer of polyurethane, for example. Gripper pads 24, 25 are mounted to upper arm 22 and lower arm 23 via gripper bars 62, 63. Each gripper pad 24, 25 has a bore 64, 65 into which bars 62, 63 fit. Pads 24, 25 can be rotationally fixed to bars 62, 63 via a collar screw 60. The bores 64, 65 may be eccentric to the diameter of gripper pads 24, 25. By loosening collar screws 60, gripper pad supports 61 may be loosened to loosen bores 64, 65 and thus pads 24, 25 may be rotated. This can increase or decrease pressure on products, as the eccentric permits adjustment of the contact location between pads 24, 25. In addition, gripper pads 24, 25 may be coated in a layer of polyurethane, so gripper pads 24, 25 may be rotated to replace worn out sections of polyurethane.
FIG. 4B shows gripper pad 24. Gripper pad 24 has a bore 64 and a diameter 66. Bore 64 is eccentric with respect to outer diameter 66. Gripper pad 24 may be rotated around bore 64 into position 68 via fixed collar screw 60 thus increasing the amount of pressure applied to printed product 40, since the contact point of gripper pads 24, 25 changes.
Patent Application
20080007076
