METHOD AND APPARATUS FOR ENVELOPING AND AN ENVELOPE SHEET

摘要

1396229 A method, and apparatus, for enveloping an envelope sheet B L CASSEL 23 May 1973 24550/73 Heading B8C A method of producing a sealed envelope with a mail item included therein comprises arranging a flat envelope sheet in a first plane, and a mail item sheet, of a somewhat smaller width and length, symmetrically to the envelope sheet in a second plane parallel to and adjacent the first plane, applying a force substantially perpendicular to, and through a centre line of, the mail item sheet, such that the latter, whilst being folded about said central line, is moved through said second plane towards the envelope sheet in the first plane to fold the envelope sheet about its central line enclosing the mail item sheet, and to move the envelope sheet and the mail item sheet through the first plane; and thereafter applying pressure to the folded sheets so as to press the envelope sheet edges projecting beyond the mail item sheet against each other for adhesively securing said edges. As shown, a planar tray 1, for receiving a mail item sheet and which is divided by a transverse slit 3 and has guide strips 2 along its side edges, is located symmetrically above a tray 4 which is similarly constructed, but which has overall dimensions which slightly exceed those of the tray 1, to receive an envelope blank. As a plunger 7, located above the tray 1 and having a head 7 which is adapted to pass through the slits 3, 6, is moved downwardly it folds a mail item sheet, about a centre line as it pushes the sheet through the slit 3, further downward movement of the plunger 7 causing an envelope blank in the tray 4 to be folded symmetrically about the folded mail item as both are transferred downwardly through the tray slit 6. The side edges of the folded envelope blank, which carry a pressure-sensitive adhesive and which extend beyond the folded mail item, enter the nips between pairs of rotating, pressing wheels 13, 14 and 131, 141 which are mounted on the ends of corresponding axles 12, 13 and which seal said side edges. The downward movement of the plunger 7 is arrested when the folded envelope blank is caught by the wheels 13, 14 and 131, 141. After passing the pressure wheels 13, 14 and 131, 141 the front edge of the folded envelope blank enters between a pair of rolls 16, 17 which complete the sealing of the envelope blank by pressing the trailing edges thereof, which carry adhesive, together. The sealed envelope then falls on to a guide 18 for conveyance, e.g. to a franking machine. The adhesive agent may be applied to the edges of the envelope blank immediately before the edges are pressed together. An envelope blank Fig. 4, not shown, has, on one side, a peripheral strip of adhesive (21) which is preferably slightly wider than half the difference between the width of the mail item and the envelope blank, and preferably has a fold line (24), a tear perforation being provided at (25). The plunger 7 may be replaced by a filamentary member which remains in the sealed envelope.