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US 6,003,442 AGranted
Dynamic clamps for external drum platesetter
AssigneeScitex Corporation Ltd.
InventorsYehuda Barnes Solomon, Moshe Beres
Life of this patent
Estimating the term…
Abstract
A clamp for gripping an edge of a plate that is mounted on the surface of a rotatable drum. The clamp includes a hinge, attached to the drum and including a pivot axis, and a gripper, formed to have a tip, operative to press the edge of the plate against the drum. The gripper is attached to the hinge so that the center of mass of the gripper is in a direction from the pivot axis that is generally opposite the direction of the tip from the pivot axis.
Claims16
An apparatus for clamping a flexible sheet medium onto a rotatable support surface with forces that increase as the rotational speed of the support surface increases, said apparatus comprising:
- a rotatable support member, having a cylindrical support surface, for supporting the flexible sheet medium thereon;
- at least one clamp, attached to said support member and operative to clamp an edge of the sheet medium onto said support surface with a clamping force that is partly derived from a centrifugal effect during rotation of said support member;
- and
- release means operative to directly engage any of said at least one clamp, while stationary, so as to counter its clamping action;
- said clamp including:
- a hinge, attached to said support member and having a pivot axis that is generally parallel to a nearest section of said support surface;
- a gripper, attached to said hinge so as to be pivotable about said pivot axis;
- and
- a spring attached to said hinge and to said gripper;
- said gripper being formed to have a tip and a body section, said body section having a center of mass and an outer surface which are disposed in a direction from said pivot axis that is generally opposite the direction of said tip from said pivot axis;
- said tip being operable to engage said edge of the sheet medium for clamping it onto said support surface;
- said spring being operative to impart a pivoting momemt to said gripper such as to cause said tip to press on said edge of the sheet medium against said support surface;
- and
- said outer surface being pushably engagable by said release means.
11 more elements
A plate marking apparatus comprising:
- a rotatable drum, having a cylindrical support surface for mounting one or more plates thereon;
- and
- a plurality of clamps, each operative to clamp an edge of a plate, at least two clamps being slidable clamps, each slidable clamp being slidably attached to said drum and operative to clamp an edge of a plate onto said support surface with a clamping force that is partly derived from a centrifugal effect during rotation of said drum and including:
- a base, slidably attached to said drum and including a hinge with a pivot axis that is generally parallel to a nearest section of said support surface;
- a gripper, attached to said hinge so as to be pivotable about said pivot axis;
- and
- a spring attached to said base and to said gripper;
- said gripper being formed to have a tip and a body section, said body section having a center of mass and an outer surface which are disposed in a direction from said pivot axis that is generally opposite the direction of said tip from said pivot axis;
- said tip being operable to engage said edge of a plate for clamping it onto said support surface;
- and
- said spring being operative to impart a pivoting momemt to said gripper such as to cause said tip to press on said edge of a plate against said support surface.
8 more elements
An apparatus for clamping a flexible sheet medium onto a rotatable support surface with forces that increase as the rotational speed of the support surface increases, said apparatus comprising:
- a rotatable support member, having a cylindrical support surface, for supporting a flexible sheet medium thereon;
- at least one clamp, slidably attached to said support member and operative to clamp an edge of the sheet medium onto said support surface with a clamping force that is partly derived from a centrifugal effect during rotation of said support member;
- each clamp including:
- a base, slidably attached to said support member and including a hinge with a pivot axis that is generally parallel to a nearest section of said support surface;
- a gripper, attached to said hinge so as to be pivotable about said pivot axis;
- and
- a spring attached to said base and to said gripper;
- said gripper being formed to have a tip and a body section, said body section having a center of mass and an outer surface which are disposed in a direction from said pivot axis that is generally opposite the direction of said tip from said pivot axis;
- said tip being operable to engage said edge of the sheet medium for clamping it onto said support surface;
- and
- said spring being operative to impart a pivoting momemt to said gripper such as to cause said tip to press on said edge of the sheet medium against said support surface.
8 more elements
A method for mounting a plate on the surface of a rotatable drum, comprising the steps of
- (a) providing a plurality of clamps, each operative to grip an edge of the plate, said clamps being configured in two groups, a first group being fixedly attached to the drum and aligned along a line essentially parallel to the axis of the drum and a second group being slidably attached to the drum, each clamp being slidable along a circumferential path;
- (b) providing a mechanism reversibly operative on any of said clamps in said second group to engage it, to prevent it from gripping and to cause it to become slidable with respect to the surface of the drum;
- (c) causing all of said clamps in said second group to stay clear of an area of the surface of the drum, such that will allow attachment of the plate thereto;
- (d) causing suitable ones of said clamps in said first group to grip a first edge of the plate;
- (e) temporarily attaching the plate to the drum's surface;
- (f) operating said mechanism so that desired ones of said clamps in said second group become engaged and slidable and are presented from gripping;
- (g) rotating the drum while said desired ones of said clamps continue to be engaged by said mechanism and slide circumferentially with respect to the drum;
- and
- (h) operating said mechanism so that said desired ones of said clamps become disengaged and grip a second edge of the plate.
6 more elements
Dependencies are inferred from the claim text.