| 摘要 |
1368279 Packaging; feeding webs TETRA PAK INTERNATIONAL AB 31 Dec 1971 [7 Jan 1971] 60901/71 Headings B8C and B8R [Also in Division B5] A roll 46 of packaging material comprises a web having a plurality of openings and tabs heat sealed to the web over the openings. The web may be used to form tetrahedron or parallelepipedic containers and may comprise a laminate of one or more layers of paper laminated on one side to layers of polyethylene or polypropylene and having on the other side a layer of wet strength paper, and/or a layer of wax or polyethylene. The paper layer(s) may be replaced by a layer of foam polystyrene covered on one or both sides by a layer of polystyrene. The web may include a metal foil layer. A web 10 is fed through a supply chamber 30, and tension control 32 to a chamber 34 where a set length of the web accumulates. Rollers 245, 260 then pull the set length successively through a punch chamber 36 and a tab heat seal chamber 38. The web passes into a collection chamber 42 before being wound into the roll 46. Photocells 62, 66 in the chambers 30 and 42 control the speed of rollers 22, 24 and 44, 45 feeding the web into and out of, respectively the two chambers. In the chamber 34 with an exit clamp 74 closed, accumulators 76, 77 are moved downwardly by cam actuated rods and a roller 100 moved downwardly by a cylinder 78. When the accumulators 76 and the roller 100 have completed their movement and a photo-cell 50 has detected indicia on the web the entry clamp 72 closes and the cylinder 78 retracts, the final movement of accumulator 77 taking up the stack in the web. The roller 245 is alternately pressed against driven roller 260 to pull the web out of the chamber 34 and against driven roller 240 to maintain its rotational speed. The punch chamber 36 comprises two rows of staggered rods 128 which are reciprocated by a cam 130 to punch holes in the web when it is stationary. In chamber 38 heated platens 152 reciprocated by arms 155 (Fig. 14) press a tab over each opening, the tabs being cut by blades 162 from tapes 164 fed by rollers 168 intermittently rotated by a ratchet. Each tape is supplied from a roll in a bin and is passed over a stop motion wire which is actuated by the tape pulling the core tube of the roll against it on exhaustion of the roll. The tape then pasess over pull back preventer 172 to eccentrically mounted rollers 176, 178 which are moved upwardly by the arm 155 to supply tape to roller 168 just before it is rotated. A photo-cell 70 detects the absence of a tab over an opening. |
