GB895028A - Improved method and apparatus for treating sheet material - Google Patents

Abstract

895,028. Stretching sheet material such as leather. BLATZ, P. A. June 30, 1960, No. 23015/60. Class 76. Sheet material, the physical properties of which are improved by stretching, is stretched and suppled by the application of opposing forces which are laterally fixed relative to each other and to the sheet, these opposing forces being applied substantially perpendicularly to the sheet and upon opposite sides of it in spaced zones upon one side of the sheet and yieldably in a continuous zone upon the other side of the sheet in line with and in between the spaced zones, said opposing forces being strong enough to prevent any lateral movement of the sheet disposed in the path of said opposing forces which meet each other at said spaced zones and to force the length of the sheet disposed between said spaced zones out in the direction of the forces applied in the continuous zone to stretch said lengths. In an apparatus for carrying the invention into effect, a piece of leather 18 (Fig. 1) is drawn by the rotation of steel discs 14 which are from 3/16 to # inch in thickness into firm contact with the surface of an elastomeric body 12 which may be made from rubber of 10-50 durometer hardness. This body is firmly supported on a member 20 to apply a force which reacts against the contacting ends 13 of the discs 14 and the adjacent surfaces of body 12, thus causing the leather to be stretched and suppled at the same time. In a modification (Fig. 3) a substantially thick belt 12b of 30 durometer rubber about 4 to 5 feet in width is supported and rotated upon a pair of steel drums 34 which are mechanically rotated. Supporting drums 36 are rotatably mounted in contact with the lower surface 38 of the upper traverse of belt 12b. A series of rollers 40b, 42b and 44b successively repeated in that order are disposed along the upper surfaces of the upper traverse of the belt 126. Rollers 40b and 42b include spiral ribs 46b and 50b respectively which are of opposite hand one from the other to increase the suppling effect. Roller 44b is rotated by mechanically rotated pulley 52b and belt 54b at a peripheral speed higher than that of the belt 12b. Alternatively roller 44b may be allowed to rotate freely. In Fig. 9 a reciprocating projection means 60e is mounted above the surface of the rubber belt 12e, and a reciprocating means 64e is connected to a projection means 60e to move the projection means in and out of firm engagement. A series of projections 66e extend from the bottom of plate 62e and cause the leather (not shown) to be forced against the belt 12e which is itself supported by a force-resisting plate 68e. Compound rollers and rollers fitted with helical ribs set at 45 degrees may also be used.