GB957519A - Tentering machine - Google Patents

Abstract

957,519. Film-stretching apparatus. B. KAMPF, E. KAMPF, and H. KAMPF, [trading as ERWIN KAMPF MASCHINENFABRIK]. July 21, 1960 [July 25, 1959], No. 25485/60. Heading B5B. [Also in Division D1] A tentering machine for transversely stretching a travelling web 1 comprises a plurality of separate clips 8 to grip the longitudinal edges of the web 1 whilst moving along two tracks which lie one on each side of the web 1 and diverge transversely outwardly in the plane thereof, a screw conveyer 41, 42 adapted to move the clips 8 along each track, means at the entry of each track to close the clips to grip the web edges and means at the exit of each track to release the grip of the clips 8. The threads of the conveyers 41, 42 are in the form of grooves 44, as shown, or ribs with which the clips 8 engage and preferably progressively increase in pitch as the conveyers diverge so that the web 1 is stretched longitudinally as well as transversely. The conveyers 41, 42 driven by motors 119 and 120 are carried by arms 30, 31 pivotable about axes 22, 23 and mounted on nuts 28, 29. Each of the arms 30, 31 carries at least one screw conveyer. The threads of the nuts 28, 29 are of the opposite hand to each other so that rotation of a spindle 104 by a hand wheel 34 alters the width to which the web is to be stretched. Supplementary conveyers 127, 128 comprising endless conveyers entrained around pulleys 10, 11, 113, 114, 117, 118 and including slides 147, 148, Fig. 8, receive the clips 8 running off the conveyers 41, 42 and return them to the beginning thereof. The pulleys 10, 11 mounted on nuts 100, 99 and the pulleys 117, 118 mounted on nuts 109, 110 are adjustable by hand wheels 106, 107 respectively. In the stretching zone 7 an infra-red heating device (not shown) may be provided to heat the web and therefore the clips. These are partly cooled in the zone 129. The clips are passed through an additional cooling zone 96 which may consist of a cooling coil 97 or a tunnel in which nozzles 98 spray the clips with a cooling fluid. Each clip 8 may be equipped with two guide bolts 45, 46 of which the bolt 45 is guided in the helical groove of the conveyer 41 and the bolt 46 engages a guide 47, Fig. 4, or a second conveyer 43, Fig. 5 (not shown). In the latter construction guides 48, 49 prevent transverse movement of the clip 8 relative to the conveyers 41, 43. The jaws 18, 19 at each clip 8 are pivoted at 50 and are preferably urged closed by a spring 51 when they are not held open by cams 16, 17. The clips 8 may be transferred from the conveyers 127, 128 to the conveyers 41, 42 and vice versa by star wheels 53, Fig. 6, each having prongs 53 to push the clips 8. In a modification, Figs. 7 and 8, each clip 8b comprises a plate 54 on which the bolt 45 is secured and which has a post 55, to which a rocking arm 56 is hinged, connected thereto. A spring 65 urges the arm 56 into clamping engagement with the web. A projection 57 on the arm 56 runs against a guide 58 to operate the clip. The tentering machine may be structurally combined with a known roll cutting machine. The machine may be used for stretching foils, synthetic plastic foils, textiles or paper.