GB677640A - Improvements in envelope making machines - Google Patents

Abstract

677,640. Making envelopes. CARLAW (ENGINEERS), Ltd., D. Oct. 5, 1950 [May 13. 1949], No. 12772/49. Class 94(ii) In a machine for gumming and folding envelope blanks provided with a pair of side flaps and top and bottom closing flaps the blanks are fed forwardly in succession by an endless chain conveyer 11 to a pair of co-operating feed rollers 14, 15 which advance them to a gumming device which comprises a roller 12 provided with circumferentially spaced relief pads arranged to apply gum to the leading and trailing edges respectively of the blank and, in addition, is provided with a presser member located within a cavity in proximity to the pad that gums the trailing edge of the blank and arranged so that it can be projected or retracted in synchronism with the advance of the blanks to act as a feeding device in co-operation with a pressure roller 13 mounted beneath the gumming- roller. The presser member 20, Fig. 3, comprises a metal pad at the outer end of a slidable plunger 25 which is located within a radial aperture in the gumming roller 12 and urged outwardly by a compressed helical spring 26. Movement of the plunger is controlled by a bar 27 which is slidable within an axial passage 28 in the gumming roller shaft 29 and has a wedgeshaped inner end 30 engaging within a corresponding slot in the plunger and operating in opposition to a compressed spring 31 located within an axial orifice, the other end of the bar 27 being provided with a roller 32 which bears against a stationary cam face 33. The arrangement is such that the cam 33 effects an inward longitudinal movement of the gumming roller 12, thereby forcing the plunger 25 inwardly and retracting and holding the presser 20 clear of the gum-transferring roller 22. The shaft 29 of the gumming- roller 12 is resiliently supported in end bearings 29<SP>1</SP> to allow for inequalities in the thickness of the paper blanks. Gumming pads 16 and 21 are mounted on removable arcuate plates 12<SP>1</SP>, 12<SP>2</SP> which enable ranges of different envelope sizes to be dealt with by interchanging with others of a set of pads. The pressure roller 13 is of the full width of any blank that the machine will accommodate and although driven at the same peripheral speed as the gumming roller 12 is of slightly larger diameter so that adhesive coming on the pressure roller is at recurrently different places. From the gumming-roller the blank is advanced by two pairs of co-operating: rollers 14", 15<SP>1</SP> which engage the side flaps, the rollers 14" being freely mounted on spring-pressed arms 18'. These rollers feed the blanks to the creasing-box below a plunger 34, the correct alignment of the blanks relative to the plunger being determined by a pair of gauges 35 which are reciprocated towards and away from the plunger, under the control of means which raise them behind each blank so that they advance it with a direct pushing action. The gauges are each pivoted to one end of a longitudinally reciprocating rod 37 which moves within guides in one of the two stationary carrier plates 43 forming the sides of the creasing-box, each gauge being drawn over a cam surface 36<SP>1</SP> which raises it through a slot 42 in the carrier plate into a position to engage behind a side flap of the envelope. The rods 37 are reciprocated by double-armed levers 38' operated by arcuate racks 40 linked to the machine drive. Adjustment of the stroke of the rods 37 for different sizes of blanks is effected by a nut 46 on the screw-threaded end of a pivotal extension 37<SP>1</SP> of the rod 37. Lateral adjustment of the gauges 36 relative to the carrier plates 43 is provided by bolts 49, Fig. 7, which pass through transverse holes in the carrier plates and. have slotted heads 52 to receive and guide the rods 37, the bolts being adjusted by knurled finger nuts 50. Specification 677,710 is referred to.