Method of, and means for folding a container blank into a tubular body

Claim 3

A method as claimed in claim 1 wherein said steps are carried out at successive stations and further comprising passing the blank from one station to the next for carrying out the successive steps.

Claim 4

A method as claimed in claim 1 wherein the step of flexing the folded and sealed blank to break the fold lines comprises flattening the sealed blank in a diagonal plane opposite to that plane in which it is flattened during sealing.

Claim 5

A method as claimed in claim 1 wherein the blank is squared to provide a substantially rectangular cross section.

Claim 6

Apparatus for forming a tubular container body from a flat blank of package-forming material having a heat-sealable surface, said blank having four side-by-side panels, one of said outer panels including an outer sealing flap therealong said panels and flap being separated by parallel fold lines therebetween, said apparatus comprising in succession, means for simultaneously folding up the two outer panels about their fold lines to positions upstanding from the plane of the inner panels, means for heating the outer edge zones of the upstanding panels, means for folding down the upstanding panels toward the inner panels so that the heated edge zones overlap, means for applying pressure to the overlapping edge zones to seal said edge zones together, means for flexing said folded and sealed blank to break the fold lines and means for squaring said flexed blank to form the tubular container body.

Claim 7

Apparatus for forming a tubular container body from a flat blank of package-forming material having a heat-sealable surface, said blank having four side-by-side panels, one of said outer panels including an outer sealing flap therealong said panels and flap being separated by parallel fold lines therebetween, said apparatus comprising in succession, means for simultaneously folding up the two outer panels about their fold lines to positions upstanding from the plane of the inner panels, means for heating the outer edge zones of the upstanding panels, means for folding down the upstanding panels toward the inner panels so that the heated edge zones overlap, means for applying pressure to the overlapping edge zones to seal said edge zones together, means for flexing said folded and sealed blank to break the fold lines and means for squaring said flexed blank to form the tubular container body.

Claim 8

Apparatus as claimed in claim 5 and further comprising conveyor means for advancing the blank from one means to the next means.

Claim 9

Apparatus as claimed in claim 6 wherein said flexing means, upon receiving the sealed blank flattened in one diagonal plane of the tubular body flattens the blank in the other diagonal plane of the body.

Claim 10

Apparatus as claimed in claim 5 and further comprising means for squaring the flexed flattened blank to form a tubular body having a substantially rectangular cross section.

Claim 11

Apparatus as claimed in claim 5 wherein the means for folding up the outer panels includes rotatable suction means for folding said outer panels and retainer means for holding the folded panels in their upward direction after said suction means is released.

Claim 12

Apparatus as claimed in claim 9 wherein said retainer means comprises bars movable to positions behind the panels after they have been folded up to support said panels.

Claim 13

Apparatus as claimed in claim 9 and further comprising means for moving said suction means and said retainer means synchronously.

Claim 14

Apparatus as claimed in claim 10 wherein said bars are spaced from said outer panels so that said panels spring back to engage said bars when said suction means is released.

Claim 15

Apparatus as claimed in claim 5 wherein said heating means comprises one means for heating the edge zone of one panel and a second means for heating the edge zone of the other panel.

Claim 16

Apparatus as claimed in claim 13, wherein said heating means comprises burners for providing gas jets for heating the edge zones of said panels.

Claim 17

Apparatus as claimed in claim 6 and further comprising means for holding the upstanding panels at substantially the same angle with respect to the inner panels when advanced from the means for folding up the outer panels to the heating means.

Claim 18

Apparatus as claimed in claim 15 wherein said holding means comprises a plurality of rollers in series.

Claim 19

Apparatus as claimed in claim 5 wherein the means for folding down the upstanding panels includes means for receiving the panels at substantially the same angle with respect to the inner panels as when passing the heating means.

Claim 20

Apparatus as claimed in claim 17 wherein said receiving means comprises a series of rollers.

Claim 21

Apparatus as claimed in claim 17 wherein said receiving means are rockable for folding down the upstanding panels toward the inner coplanar panels of the blank.

Claim 22

Apparatus as claimed in claim 18 wherein the axes of said rollers are disposed at right angles to the axis of a rotatable shaft extending parallel to the passage of the blank to the means for folding down said upstanding panels.

Claim 23

Apparatus as claimed in claim 5 wherein said means for applying pressure to seal said heated edge zones together comprises pressure roller means.

Claim 24

Apparatus as claimed in claim 21 wherein said pressure roller means includes a cooled roller means for cooling the sealed edge zones.

Claim 25

Apparatus as claimed in claim 5 wherein said flexing means comprises a pair of elements reciprocable toward and away from each other and adapted to receive the flattened blank from the pressure sealing means when spaced apart from each other and to flex the flattened blank when said elements move toward each other to flatten the blank in the opposite plane of the body.

Claim 26

Apparatus as claimed in claim 23 wherein said flexing means further includes suction means for holding a panel of said flexed blank when said reciprocable elements are withdrawn after flexing said folded blank.

Claim 27

Apparatus as claimed in claim 24 and wherein said squaring means includes a plate means for engaging the panel adjacent the panel held by said suction means for positioning said adjacent panel at right angles to the panel held by the suction means and thus square the flexed blank to form a substantially rectangular tubular container body.