Patent GB-1075985-A (GB)
Title: Improvements in and relating to a machine for applying material internally to a length of flexible tubular material
IPC: B29C31/00
Filed: 1965-09-14
Abstract: 1,075,985. Making valve bags &c. G. GALIMBERTI. Sept. 14, 1965 [Sept. 15, 1964], No. 39096/65. Heading B5D. [Also in Division F2] A machine for attaching material internally to a length of flexible tubular material comprises an internal structure 8 (Fig. 1) which is retained in the interior of the tubular material by rollers 9 supported through the wall of the tubular material, on rollers 5 of an external structure. The internal structure 8 includes a supply 17 of material 18, and a device for applying the material 18 to the inside wall of the tube. In the form shown, which is a machine for forming valves in the wall of plastics bag forming material, the tubular material 3 is fed in flattened form to a roller 2a, and then passes over resiliently-mounted tensioning wheels (15), Fig. 3 (not shown) at the level of rollers 9, Fig. 1, to produce a rectangular cross-section tube between the rollers 9 and further rollers 10, which coact through the tubular material 3 with external rollers 6 to centralize the structure 8. Material 18 is fed over a roller 20 into contact with the tubular material 3, an externally mounted idler roller 22 being engageable against the tube wall to draw material 18 from the supply 17 as the tubular material is fed downwardly. The roller 22 may alternatively be driven. Below the roller 20 a member 27 directs the material 18 away from the material 3, and an external blade 39 engages the tubular material to cut a longitudinal slit. Below the member 27 the material 18 is directed back into contact with the tubular material 3, passing between it and a dolly 40. An external welding die 42 then welds the materials 3 and 18 together in the slitted region of the material 3, to form a valve (Fig. 2, not shown). Resilient portions 41 on the dolly 40 co-operate with the shaped die 42. An external member 50 pushes against the material 3 to engage a linkage 36 mounted on the internal structure 8, thereby operating a cutter 29 to cut the material 18. The tubular material 3 then passes over further tensioning wheels at the level of rollers 10, and returns to its original flattened form over a roller 2b. In another embodiment (Figs. 4-15, not shown) the form of cross-section of the tube is changed in two stages, by tensioning wheels, firstly to that of the above embodiment and then to substantially rectangular form rotated through 45 degrees relative to the first crosssection. After processing the tube returns to its original or flattened form through a reverse process. In this embodiment the internal structure (67), Fig. 9 (not shown), includes a plate (70), carrying certain tensioning wheels and support rollers, the plate being laterally movable to allow for different sizes of tube. Resilient mounting of tensioning wheels (92), Fig. 11 (not shown), on the plate (70) allows for small variations in tube size. The engagement of an orientatable roller (59) outside the tube with an internal roller (73) mounted on oscillatory bearings acts on the tube to remove twist prior to re-flattening. Shaped aprons (76, 77) mounted rigidly and resiliently respectively on structure (67), assist in directing the tubular material correctly on to the output roller (54), similar aprons at the top of the structure (67) assisting in the opening of the tube. The welding arrangements are generally as in the previous embodiment, but the material applied to the internal wall of the tube is cut by a resistance heater (114), Fig. 14 (not shown), and a roller (139) prevents feed of more material if the welded portion of material is not properly cut. Electrical power for the heater (114), and for other purposes is provided through a transformer having its primary and secondary windings (147a, 147b) respectively outside and inside the tubular material. A switch (145) detects absence of the material being applied, the relevant signal being passed out from the apparatus through the transformer (148d, 148b) arranged similarly to the previous transformer. In this embodiment the internal structure (67) is supported from below by rollers (71, 58), Fig. 9 (not shown), and is centred by equivalent upper rollers.