| 摘要 |
1,136,714. Stencils. LUXAR S.A.R.L. 24 Jan., 1966 [25 Jan., 1965], No. 3200/66. Heading B6C. An apparatus for successively fitting taut screens, e.g. silk screens for printing, to a frame comprises supporting means for the frame, screen stretching members actuable by a pressure fluid to stretch each screen before it is attached to the frame, frame compressing members actuable by a pressure fluid to impart a preliminary compression to the frame in a manner opposed to the stretching forces before attachment of the screen and means for supplying a pressure fluid to both members to subject the frame to compression forces proportional to the stretching forces exerted on the screen. The pressure fluid actuable means preferably consist of a series of jacks mounted on a table, each of said jacks comprising traction means for pulling the screen and pressure means for compressing the frame, e.g. the jacks may each include a cylinder and a piston slidable in the cylinder, the stretching and compressing being carried out one by the cylinder and the other by the piston. The table may be provided with two sets of mutually perpendicular guideways formed between guide heads, each of the jacks being slidable along their respective guide paths. In Fig. 3, a single jack is shown. A cylinder 6 is provided in a support 5. The cylinder contains a piston 7 connected to a piston-rod 8. Rod 8 is connected by a transverse bar 13 to spring strip 16 which is in turn connected to assembly 17 which assembly forms a clamp for attaching to the screen 4 which is to be stretched. The screen 4 holds one edge of the frame 35 in the stepped portion 34/36 provided in the cylinder support 5. The chamber 11 at the right hand end of cylinder 6 behind the piston 7 can be supplied with compressed air as the " pressure fluid ". A base-plate 41 is provided on each jack support to slide under the overhanging top plates 39 of circular guide heads (38, Fig. 2) so that each jack may slide backwards and forwards between two parallel sets of guide heads but is held on to the table 1. Opposite rows of jacks in their respective guides may be fed simultaneously with compressed air resulting in regular stretching of the screen 4 and in compression of the frame with pressure proportional to the traction exerted on the screen. |
