Method and apparatus for making expansible gusset envelopes

Claim 2

In a machine for fabricating an expansible gusset envelope from a blank having first and second panels hinged to each other along triple transverse fold lines defining inwardly collapsible bottom gusset sections therebetween, and flaps hinged to the sides of one of said panels along triple longitudinal fold lines defining inwardly collapsible side gusset sections therebetween, and including a tab hinged to each side gusset section with adjacent tabs hinged to each other along a line registering with the medial longitudinal fold line detached from the bottom gussets, apparatus comprising: bending means for folding each of the side gusset sections inwardly with respect to each other, crimping means for crushing adjacent tabs along the line hinging them together to define inwardly directed corner gusset saddles at each side with the hinge line thereof oriented generally transverse to the medial longitudinal fold line, means for folding the bottom gussets inwardly with respect to each other, including means for tucking said bottom gussets in glued nested disposition within the corner gusset saddles, and means for folding said flaps and said other panel in glued disposition with respect to each other and in overlying disposition with respect to the first panel.

Claim 3

The apparatus of claim 1 including conveying means for transporting the blanks longitudinally with respect to the longitudinal fold lines during the inward folding of said side gusset sections.

Claim 4

The apparatus of claim 2 including second conveying means for transporting the blanks longitudinally with respect to the transverse fold lines during inward folding of said bottom gusset sections.

Claim 5

The apparatus of claim 2 wherein said crimping means comprises a cam interposed in the path of travel of said inwardly folded side gusset sections.

Claim 6

The apparatus of claim 2 including means to bend back each pair of tabs along the line hinging them to the side gusset sections.

Claim 7

The apparatus of claim 5 wherein said bending means comprises a longitudinally extending rail of sidewise Vee-cross section, a longitudinally extending rib having a cross section complementary with that of the rail and adjacently spaced therefrom to define a V-shaped channel therebetween, and blade means for directing the side gusset sections with their bent back tabs within said V-shaped channel.

Claim 8

The apparatus of claim 6 including a cam interposed in the path of travel of said side gusset sections as they emerge from said V-shaped travel.

Claim 9

The apparatus of claim 7 wherein said cam includes a finger which engages the leading edge of said side gusset sections along the line hinging the tabs thereto so as to effect rotation of said cam, and a pawl on said cam which crushes the tabs along the line hinging them together during rotation of said cam.

Claim 10

The machine of claim 8 wherein said rib includes a V-shaped notch at the downstream end thereof, said notch forming an angular wall for shaping triangular gusset corners in the side gusset sections when said tabs are crushed into saddle configuration by said cam.

Claim 11

The apparatus of claim 9 including ironing means to press said side gusset sections together.

Claim 12

The apparatus of claim 10 including ironing means to press said bottom gusset sections together with said saddles nested therein.

Claim 13

Apparatus for fabricating an expansible gusset envelope from a blank having first and second panels hinged to each other along first, second and third transverse fold lines which define inwardly collapsible bottom gusset sections therebetween, and flaps hinged to the sides of one of said panels along first, second and third longitudinal fold lines which define inwardly collapsible side panel sections therebetween, and including a tab hinged to each side panel section along a line registering with the first transverse fold line and hinged to each other along a line registering with the second longitudinal fold line, comprising: conveying means for transporting the blanks longitudinally with the longitudinal fold lines, curling means for bending back the tabs along the line hinging them together, means for folding the flaps inwardly along the first longitudinal fold line, outwardly along the second longitudinal fold line, and inwardly along the third longitudinal fold line, crimping means for crushing said tabs and the underlying portion of the side panel sections along the line hinging the tabs together to define corner gusset saddles whose hinge line is generally transverse to the second longitudinal fold line, means for folding the other panel inwardly along the first transverse fold line, outwardly along the second transverse fold line and inwardly along the third transverse fold line so as to tuck the outer margins of the bottom gusset sections into nested engagement within the corresponding corner gusset saddles.

Claim 14

Apparatus for fabricating an expansible gusset envelope from a blank having first and second panels hinged to each other along first, second and third transverse fold lines which define inwardly collapsible bottom gusset sections therebetween, and flaps hinged to the sides of one of said panels along first, second and third longitudinal fold lines which define inwardly collapsible side panel sections therebetween, and including a tab hinged to each side panel section along a line registering with the first transverse fold line and hinged to each other along a line registering with the second longitudinal fold line, comprising: conveying means for transporting the blanks longitudinally with the longitudinal fold lines, curling means for bending back the tabs along the line hinging them together, means for folding the flaps inwardly along the first longitudinal fold line, outwardly along the second longitudinal fold line, and inwardly along the third longitudinal fold line, crimping means for crushing said tabs and the underlying portion of the side panel sections along the line hinging the tabs together to define corner gusset saddles whose hinge line is generally transverse to the second longitudinal fold line, means for folding the other panel inwardly along the first transverse fold line, outwardly along the second transverse fold line and inwardly along the third transverse fold line so as to tuck the outer margins of the bottom gusset sections into nested engagement within the corresponding corner gusset saddles.

Claim 15

The apparatus of claim 12 including means for glueing said corner gusset saddles within said bottom gusset sections.

Claim 16

The apparatus of claim 13 including means for glueing said second panel and said flaps into overlying disposition with said first panel.

Claim 17

The apparatus of claim 12 wherein said crimping means comprises a cammed pawl interposed in the path of travel of the inwardly folded side panel sections.

Claim 18

The apparatus of claim 15 wherein said cammed pawl includes a lobe for engaging the side panel sections along the line hinging the tabs thereto so as to effect rotation of said cam, and a portion of said cam abutting the tabs along the line hinging them together during cam rotation.