Patent GB-875803-A (GB)
Title: Folding mechanism for envelope machines
IPC: B31B19/00
Filed: 1957-12-04
Abstract: 875,803. Sheet-delivery apparatus. SMITHE MACHINE CO. Inc., F. L. Dec. 4, 1957 [Dec. 21, 1956], No. 37821/57. Class 100(1) [Also in Group XVII] Making envelopes. Folding mechanism. for envelope making machines, adapted for relatively folding a body portion 12 and an adjoining flap portion 18 of an envelope blank 10 along an intervening score line 14 comprises a drum 32 for carrying the blank continuously forward at high speed with one of the portions leading and the other trailing, suction means 34 for holding the trailing portion immovably to the drum in an area closely adjacent to the score line, means 42 for deflecting the leading portion away from the drum to initiate and carry forward the folding of the blank and a member 44 co-operative with the drum and disposed to intercept the deflected leading portion, turn it down on to the trailing portion, and press it firmly into place. The envelopes, comprising the body portion 12, leading flap portion 18 and trailing flap portion 20, are fed over a table 38 by rollers 30 to the drum 32 when the body portion 12 is held by suction passages 34 the suction in which is caused to come on at or just before the time when the passages 34 reach blank engaging position. At the same time the flap 18 is engaged by means 42 comprising a rotating suction segment which bends the flap upwardly. The sucker 42 rotates at the same peripheral speed as the drum 32 which is designed to deal with four blanks each revolution. The sucker 42 makes two revolutions for each blank dealt with so that valve means are provided which apply suction only on every alternate revolution. The crease line 14 between the portions 12 and 18 is thus presented to the nip of drum 32 and roller 44 and the folding of the leading flap is thereby completed. The flap 18 constitutes the bottom flap of the envelope and is folded on to the previously folded and gummed side flaps 24. As the folded flap 18 emerges from the roller 44 suction is applied to further passages 36 carried on the drum 32 which hold the trailing flap portion 20 of the envelope. At the same time a blower 46, also on the drum 32, is operated to blow outwardly the envelope portions 12 and 18 so that portions 12 and 20 fold about the crease line 16. The crease line 16 is presented to the nip of the drums 32 and 48 as shown at 10a in Fig. 1. The drum 48 includes presser bars 54 and suction passages 56 to which suction is applied after the body portion of the blank has been folded back upon the flap 20 and suction is cut-off from the passages 36. The folded envelope blank is thus transferred to the drum 48 for delivery. Rotary and stationary valve members are provided on the drum 32, shaft 72 of the sucker 42, and on the drum 48 for controlling the supply of suction or air in proper timed relationship to the passages 34, 36 and blower 46, the sucker 42, and the passages 56 respectively. In a second embodiment (Fig. 14, not shown) the drum 32 may be made up of one set of four segments including the passages 34, and two sets of two segments fixed with respect to each other, but circumferentially adjustable with respect to the one set of four segments, carrying the passages 56 and blowers 46, the circumferential adjustment enabling different sizes of envelope blanks to be dealt with. In a further embodiment (Fig. 17, not shown) the blowers 46 are replaced by cam operated thrust rods which push up the body portion 12 when the trailing flap 20 is held by the suction passages 36. Bending of the portion 12 about the line 14 is attained by an S-wheel rotating at the speed of the blank and which engages the portion 12 after it has been pushed away from the drum 32 by the thrust rods. The S-wheel is located between the roller 44 and the drum 48. In this embodiment the suction passages 56 are omitted from the drum 48, transfer of the folded blank to the drum 48 being effected by further cam operated thrust rods on the drum 32. Sheet-delivery apparatus. As shown in Fig. 1 the folded envelopes held by the drum 48 pass over guides 58, over rollers 60, 62 and are then forced into a slot 71 of a rotary stacker 64. The slots are of partial spiral shape and hold the envelopes by friction when the suction to the passages 56 is cut off. The envelopes 10b are stripped from the stacker 64 by a table 72 along which the envelopes are horizontally delivered. In the embodiment where the suction passages 56 are omitted from the drum 48 and transfer of the envelopes from drum 32d (Fig. 21) to drum 48d is effected by thrust rods the drum 48d consists of a pair of discs or pulleys 214 mounted on shaft 52d between two blocks 220 also mounted on shaft 52d. Between the blocks 220, presser bars 218 are mounted with limited radial movement and are normally spring biased outwardly. Midway between the discs 214 a twoarmed block 234 is mounted which carries shoes 238 which are also mounted on springs which urge them outwardly. After operation of the thrust rods the leading edge of the envelope is engaged by fixed guide wires 258 and guided between drum 48 and driven belts 246 which cooperate with the discs 214. The envelope is delivered to the stacker 68d directly from the belts 246 and drum 48d.