Patent ID: 8052371

Claim:
A bag supply apparatus for supplying bags onto a conveyer for transporting a bag bundle stacked in such a format that an upper level bag is shifted forward, comprising a bag lifting device for lifting a rear edge of the bag bundle which is on the conveyer; and a bag feeding device, provided at a rear of the conveyer, for transporting a new bag forward, when the rear edge of the bag bundle on the conveyer is lifted, and feeding the bag between the bag bundle lifted above the conveyer and a conveyance surface of the conveyer; wherein said bag lifting device is comprised of: a pair of bag support members disposed opposite one another on either side of the conveyer and having bag supporting portions protruding inwardly and horizontally; and a rotation mechanism for imparting translational motion of rotation to the bag support members, the translational motion being symmetrical on a plane that is perpendicular to a conveyance direction of the conveyer and being in mutually diverging directions in an upper half of a rotation track of the bag support members; and wherein the rotational center and the rotational radius of the bag support members relative to both side edges of the bag bundle are configured such that the bag supporting portions of bag support members, when the bag support members are moving upward, are brought into contact from below with both side edges of the bag bundle and lift the rear edge of the bag bundle, and then the bag supporting portions are separated outwardly from both side edges of the bag bundle, wherein the bag lifting device includes, as a part of the rotation mechanism, a pair of rotation transmission members that make a translational motion of the same rotational radius and rotational direction as each one of the bag support members on a plane perpendicular to the conveyance direction, wherein the bag support members are respectively provided on the rotation transmission members wherein the rotation mechanism of the bag lifting device is comprised of: four crank mechanisms in which two of the crank mechanisms are linked to each one of the rotation transmission members, and a drive power source for operating the crank mechanisms; and wherein in said two crank mechanisms linked to each rotation transmission member: crank shafts thereof are disposed at a same height and with a distance in between in a horizontal direction, provided in parallel in the conveyance direction of the conveyer, and rotated synchronously in a same direction, crank arms thereof have a same length and are provided so as to be mutually parallel, and one of the rotation transmission members is linked to each crank pin thereof.