Improvements in and relating to methods of and machines for applying adhesive

摘要

An adhesive pattern is applied to a sheet having a plane surface by forming on said sheet a temporary relief surface corresponding to the adhesive pattern to be produced, by temporarily distorting the sheet in a manner permitting it to return readily to its plane surface form, applying adhesive to the relief surface while the sheet is subjected to the distorting force, and then permitting the sheet to return to its normal plane surface condition. In the apparatus shown, sheets a are lifted, in individual succession, by a suction feed head 23 from a hopper 10 and are carried over the gumming device 19 to a feeding means 15, 17 for box body blanks 16 to which the sheets are to be applied. The suction feed head 23 has a perforated lower plate 24, provided with a recessed surface 29 and a relief surface 28 corresponding to the adhesive pattern to be applied to the sheet a. It can be moved along the transverse rail 32 by means of an oscillating lever 39, and can also be moved vertically by means of levers 34 which carry a shaft 36 oscillated in predetermined timed relationship with the movements of the blank feeding fingers 15. The application and discontinuance of suction to the head 23 is controlled by timed valving. When a sheet a from the hopper 10 is caused to adhere to the lower face of the plate 24 it will be distorted in such a fashion that adhesive is applied only to such parts as correspond with the relief surface 28. After the application of adhesive, the sheet is brought over and pressed into contact with a blank 16, the suction head then returning upwardly and laterally, above the roller 19, to the hopper 10. The roller 19 may be replaced by an adhesive-applying brush.