Patent GB-777445-A (GB)
Title: Improvements in or relating to machines for applying adhesive to sheet materials
IPC: B05C1/08
Filed: 1953-06-26
Abstract: A machine having opposed adhesive impression and presser rolls for applying areas of adhesive to each of a series of paper or other sheets passing in regular succession therebetween, which rolls are held in normal pressure-applying position all the time the sheets are so passing, has means for preventing the presser roll from picking up adhesive from the adhesive impression roll whenever the regular continuity or flow of sheets is interrupted, <PICT:0777445/III/1> comprising a mounting for the rolls which will permit them to assume a separated or non-pressure applying position, and means operating automatically as a result of such interruption to effect the separation of the rolls.  The interruption of flow may be detected by photoelectric or mechanical means.  As shown, pre-cut blanks B1, B2 are forwarded from a feeding apparatus comprising a shoot, feed roll and feed roll brush, by a belt 16 having fingers 24, which determine the spacing of the blanks.  They are then fed through the nips of the roller pairs 26, 27, 28, 29, 30, 31, which may perform creasing or other operations on the blank, and then pass beneath the adhesive impression roller 41, journalled on a shaft 42.  Adjacent the roller 41 are aditional guiding rolls (not shown) supporting a belt or belts 48.  After passing the impression roller 41, the blanks are carried forward by the belt or belts 48 and a co-operating lower belt 47, rollers, not shown, being placed above and below the belts to apply pressure to them. The impression roll 41 is of known character and may be made so that it may be adjusted sideways, its width and shape changed, and adhesive-applying pads 56, 57, the number, size and shape being determined by the job in hand, placed on its periphery. Beneath the roll 41 is a pressure roll 60, journalled on a shaft 61 which is carried by a bent lever 62 mounted on a shaft 64. Pivoted independently on the shaft 64 is a lever arm 67, its lower end being pivoted to a link 70 connected to the core 71 of a solenoid 72 which is attached to the frame 10 of the machine.  A link 85 connects the arm 67 to the centre pivot 83 of a toggle comprising links 80, 81, connecting the bent lever 62 with a pivot 79 on a bracket fixed to the frame 10.  A spring 86 extending between the pivot 83 and an anchorage 87 on the frame 10 urges the toggle against an adjustable abutment screw 88, thus tending to lift the roll 60 into contact with the impression roll 41. Conversely, operation of the solenoid 74 separates it therefrom; but the functions of the spring 86 and solenoid 74 may be reversed, with appropriate modifications to the electrical control system for the solenoid.  This comprises manual control means and an automatic control which operates should the machine fail to feed a blank at the appropriate time.  The shaft 42 of the impression roll 41 is provided with cams 94, 95 corresponding in number and angular spacing to the adhesive impression pads 56, 57 and arranged to operate a switch 98, which has a slotted mounting 101 to permit precise adjustment of the timing.  On the line 102, 103 there is a provided a sensing device for determining the presence of the sheets; as shown this comprises a lamp 105 and a photo-electric cell 106, both adjustably mounted.  The cell 106 is connected to an amplifier 120, and when illuminated causes closure of the contacts 133A of a relay 133, which are in series with the switch 98, so that, if, owing to the failure of the feeding arrangement, a blank does not intercept the light beam when the switch 98 is closed, a circuit is completed from the mains L1, L2 through the coil 138 of relay 139, causing its two pairs of contacts 139A, 139B, to close.  A self-sustaining circuit through the contacts 139A and coil 138 is thus completed, and is only broken when the contacts 133A re-open. Closure of the contacts 139B completes a circuit through the coil 74 of the solenoid 72, thus operating the toggle mechanism and causing the roll 60 to be retracted from the adhesive impression roll 41; at the same time an indicator lamp 153 is lit.  A manual control switch 146 is provided, which, when closed, also energizes the solenoid 72 and lights the lamp 153. The roll 41 may be made retractable and the roll 60 fixed, or both rollers may be mounted for relative movement. Specification 688,210 [Group XL(b)] is referred to.