Patent ID: 6640700
Filing Date: 2003-11-04
Classification: B65B

Abstract:
An apparatus for bundling one or more objects with flexible strap material, the apparatus comprising:a frame; a track coupled to the frame and substantially enclosing a strapping station sized to receive the one or more objects, the track releasably receiving a portion of the strap material about the strapping station; a first motor coupled to the frame; a feed and tension unit coupled to the frame and having: a second motor, a feed drive roller rotatably coupled to the second motor, a feed pinch roller controllably biased against the feed drive roller, wherein the feed pinch and feed drive rollers feed a free end of the strap material about the track under control of the second motor, a primary tension drive roller rotatably coupled to the second motor, and a primary tension pinch roller controllably biased against the primary tension drive roller, wherein the primary tension drive roller and the primary tension pinch roller may retract a first upstream portion of the strap material under control of the second motor to provide a primary tensioning of the strap material about the one or more objects, and a secondary tension drive roller rotatably coupled to the first motor and a secondary tension pinch roller controllably biased against the secondary tension drive roller, wherein the secondary tension drive roller and the secondary tension pinch roller may retract a second upstream portion of the strap material under control of the first motor to provide a secondary tensioning of the strap material about the one or more objects; a joining unit coupled to the frame and positioned proximate the track and the feed and tension unit, the joining unit having first and second grippers, the first gripper retaining the free end of the strap material while the primary tension pinch and drive rollers retract the first upstream portion of the strap material, the second gripper retaining the second upstream portion of the strap material following the primary tensioning, and the joining unit joining the free end and second upstream portion of the strap material together and severing the second upstream portion from a remainder of the strap material; and wherein at least one of the feed pinch roller, the primary tension pinch roller, or the secondary tension pinch roller is coupled to a solenoid that controllably biases the at least one of the feed pinch roller, the primary tension pinch roller, or the secondary tension pinch roller against the feed drive roller, the primary tension drive roller, or the secondary tension drive roller, respectively, based on a pinch signal supplied to the solenoid, the pinch signal having a first pulse width modulated stage that provides a full pinch force and a second pulse width modulated stage that provides a reduced pinch force.