The present invention relates generally to the manufacture of book covers and particularly to the controlled and gradual establishment of contact between the adhesively coated cover cloth and cover boards during assembly of a book cover. More specifically, this invention relates to improved methods of and apparatus for fabricating book covers.
Book covers consist of a covering material, front and back cover boards and a spine board positioned between the two cover boards. The boards are glued to the covering material over their entire area. The covering material that projects beyond the cover profile defined by the boards is turned in on all four sides to define flaps. In the industrial manufacture of book covers, these manufacturing operations are accomplished by book cover assembly apparatus.
In a known cover fabrication apparatus, the cut-to-size covering material, or cover cloth, is separated from a magazine and fed to a glue roller via a cloth cylinder. A gripper bar acquires the glue-coated cloth and deposits it on a cover table. Feeder elements push the cut-to-size front and back cover boards from magazines to a ready-use supply station simultaneously with the infeeding of a spine board that has been cut to length from a reel.
Two cover boards and a spine board are simultaneously picked up at the supply station by a suction head mounted on an arm. The arm is rotated through 180.degree. to bring the boards into registration with a glue-coated cloth which is lying on the cover table. Due to the materials being brought into contact while substantially parallely oriented, i.e., the board and cloth are pressed flat against one another, attempts to increase production rate result in air being entrapped between the cloth and boards. Such entrapped air, in turn, results in blisters which give the book cover an unsightly appearance and, if they are comparatively large, will result in the cover being rejected by quality control.