Web edge sensing and guiding apparatus

Claim 2

In a web handling system for laterally guiding a web along a predetermined longitudinal path of travel in which the web engages a web guide apparatus mounted on a stationary support structure for tilting movement relative thereto in a plane of motion from a mid-position and exits from the web guide apparatus in an exiting plane transverse to the plane of motion of the web guide apparatus and wherein a web edge sensor is positioned at a sensing location to sense the lateral position of an edge of the web in said exiting plane and to operate a power means for tilting the web guide apparatus in said plane of motion in a direction to correct deviation of the web edge from a preselected lateral position, the improvement comprising means defining a rectilinear guideway on said stationary support structure paralleling said predetermined longitudinal path of web travel and extending transverse to the exiting plane of the web, means including a follower slidable along said guideway for supporting said web edge sensor, and means responsive to movement of said web guide apparatus in said plane of motion for moving said follower along said guideway in a direction and distance to cause said web edge sensor to substantially follow the component of movement of the exiting web at the sensing location that is substantially perpendicular to the exiting plane of the web while maintaining the sensor at a uniform spacing laterally of said predetermined longitudinal path of travel to thereby accommodate pass-line fluctuation of the exiting web caused by tilting of said web guide apparatus in said plane of motion.

Claim 3

In a web handling system including a movable web guide apparatus mounted on a stationary support structure for tilting movement relative thereto in a plane of motion from a mid-position, and wherein the web exits from the web guide apparatus in an exiting plane transverse to said plane of motion, a web edge sensor at a sensing location after the web exits from said movable web guide apparatus to sense movement of the web edge laterally in said exiting plane from a preselected lateral position, and power means operated by the web edge sensor for tilting the movable web guide apparatus in a direction to correct lateral deviation of the web edge from said preselected lateral position, the improvement comprising means defining a rectilinear guideway on said stationary support structure paralleling said predetermined longitudinal path of web travel and generally perpendicular to the exiting plane of the web, means including a follower slidable along said guideway mounting the web edge sensor for substantially straight line movement along a sensor shift path which is generally perpendicular to said exiting plane when the web guide apparatus is in its mid-position, and means for moving said sensor along said sensor shift path as said movable web guide apparatus is tilted in said plane of motion to substantially follow movement of the edge of the exiting web in a direction perpendicular to said exiting plane to thereby accommodate pass-line fluctuation of the web at the sensing location.

Claim 4

In a web handling system including a movable web guide apparatus mounted on a stationary support structure for tilting movement relative thereto in a plane of motion from a mid-position, and wherein the web exits from the web guide apparatus in an exiting plane transverse to said plane of motion, a web edge sensor at a sensing location after the web exits from said movable web guide apparatus to sense movement of the web edge laterally in said exiting plane from a preselected lateral position, and power means operated by the web edge sensor for tilting the movable web guide apparatus in a direction to correct lateral deviation of the web edge from said preselected lateral position, the improvement comprising means defining a rectilinear guideway on said stationary support structure paralleling said predetermined longitudinal path of web travel and generally perpendicular to the exiting plane of the web, means including a follower slidable along said guideway mounting the web edge sensor for substantially straight line movement along a sensor shift path which is generally perpendicular to said exiting plane when the web guide apparatus is in its mid-position, and means for moving said sensor along said sensor shift path as said movable web guide apparatus is tilted in said plane of motion to substantially follow movement of the edge of the exiting web in a direction perpendicular to said exiting plane to thereby accommodate pass-line fluctuation of the web at the sensing location.

Claim 5

A web handling system according to claim 2 wherein the movable web guide apparatus has a movable support frame mounted on said stationary support structure for tilting movement in said plane of motion, and said means for moving the web edge sensor includes linkage means operatively connected to said follower and to said movable support frame.

Claim 6

A web handling system according to claim 2 wherein the movable web guide apparatus includes an exiting web guide roller mounted by a movable support frame for tilting movement in said plane of motion about an effective arc center perpendicular to said plane of motion and spaced from said exiting web guide roller, said means for moving said web edge sensor including linkage means operatively connected at one end to said follower and at the other end to said movable support frame at a point laterally offset from said effective center about which the exiting web guide roller tilts.

Claim 7

In a web edge sensing and guiding apparatus for laterally guiding a longitudinally travelling web along a predetermined path of web travel including an exiting web guide roller extending transverse to a travelling web, a stationary support structure, means including a movable frame mounting said exiting web guide roller for movement relative to said stationary support structure in a plane of motion in which the exiting web guide roller is disposed generally tangent to a curved path about an effective arc center, said exiting web guide roller in the mid-position thereof extending perpendicular to the desired path of web travel and being arranged to have the travelling web extend partially therearound and exit therefrom in an exiting plane transverse to said plane of motion, a web edge sensor at a sensing location after the web exits from the exiting web guide roller for sensing lateral movement of the web edge in said exiting plane from a preselected lateral position, power means operated by the web edge sensor for moving said movable frame and said exiting web guide roller in a direction to correct deviation of the web edge from said preselected lateral position, the improvement comprising: a rectilinear guideway on said stationary support structure paralleling said predetermined path of web travel and extending generally perpendicular to the exiting plane of the web, a follower slidable along said rectilinear guideway, means mounting said web edge sensor on said follower for movement therewith along a sensor shift path, which sensor shift path generally parallels a plane through said effective arc center and perpendicular to said exiting web guide roller when the latter is in its mid-position, and a linkage operatively connected to said follower and to said movable frame for moving said sensor along said sensor shift path in a direction and distance to substantially follow movement of the edge of the exiting web in a direction normal to said exiting plane while maintaining the sensor at a uniform spacing laterally of said predetermined path of web travel to thereby accommodate pass-line fluctuation of the exiting web at the sensing location.

Claim 8

In a web edge sensing and guiding apparatus for laterally guiding a longitudinally travelling web along a predetermined path of web travel including an exiting web guide roller extending transverse to a travelling web, a stationary support structure, means including a movable frame mounting said exiting web guide roller for movement relative to said stationary support structure in a plane of motion in which the exiting web guide roller is disposed generally tangent to a curved path about an effective arc center, said exiting web guide roller in the mid-position thereof extending perpendicular to the desired path of web travel and being arranged to have the travelling web extend partially therearound and exit therefrom in an exiting plane transverse to said plane of motion, a web edge sensor at a sensing location after the web exits from the exiting web guide roller for sensing lateral movement of the web edge in said exiting plane from a preselected lateral position, power means operated by the web edge sensor for moving said movable frame and said exiting web guide roller in a direction to correct deviation of the web edge from said preselected lateral position, the improvement comprising: a rectilinear guideway on said stationary support structure paralleling said predetermined path of web travel and extending generally perpendicular to the exiting plane of the web, a follower slidable along said rectilinear guideway, means mounting said web edge sensor on said follower for movement therewith along a sensor shift path, which sensor shift path generally parallels a plane through said effective arc center and perpendicular to said exiting web guide roller when the latter is in its mid-position, and a linkage operatively connected to said follower and to said movable frame for moving said sensor along said sensor shift path in a direction and distance to substantially follow movement of the edge of the exiting web in a direction normal to said exiting plane while maintaining the sensor at a uniform spacing laterally of said predetermined path of web travel to thereby accommodate pass-line fluctuation of the exiting web at the sensing location.

Claim 9

A web edge sensing and guiding apparatus according to claim 5 wherein said effective center is spaced from the side of said exiting web guide roller at which the web enters said exiting web guide roller and said linkage is operatively connected at one end to said follower and pivotally connected at the other end to said movable guide frame at a point laterally offset from said effective center.

Claim 10

A web edge sensing and guiding apparatus according to claim 6 including a second web guide roller mounted on said movable frame adjacent said effective center.

Claim 11

A web edge sensing and guiding apparatus according to claim 5 wherein said means mounting said web edge sensor includes an arm having one end pivotally attached to said follower for straight line motion of said one end of the arm with the follower, said arm extending from said follower crosswise of the path of web travel, means mounting the other end of said arm on said stationary support structure for combined pivotal and sliding movement in a direction crosswise of said path of web travel as said one end of the arm moves in said straight line motion, and means mounting the sensor on said arm for adjustment along the arm to adapt the web guide apparatus for webs of different width.

Claim 12

A web edge sensing and guiding apparatus according to claim 8 wherein the pivot axis of said other end of the arm is located approximately medially between opposite side edges of the web.