GB761830A - Improvements in tension responsive control apparatus for weft-straighteners - Google Patents

Abstract

761,830. Automatic tension control. ROBERTSON, J. D. Oct. 25, 1954 [Dec. 2, 1953], No. 30678/54. Class 38 (4). [Also in Group XVI] A web tension-responsive control for weft straighteners comprises a web guide, the longitudinal tension of the web acting on the guide to maintain it in a first position, a biasing means, acting in opposition to this tension, provided at each end of the guide to respond to differences in tension of the selvedges, and a mechanism which associated with each end of the guide to actuate further mechanism causes equalization of the tension difference. A tension detecting roller 16 is arranged, such that a decrease in tension of either selvedge of a web passing around the roller causes actuation of a normally closed electric switch 42 at the end of the roll adjacent the selvedge which decreases in tension. The roller is rotatable on an axle 30 prevented from rotating by a pin 38 screwed into supporting member 34 provided with an elongated hole 32. The axle 30 is urged at each of its ends by a spring 52, the tension of which is adjustable by a screw 54 connected to the screw by a pin 58 and a surrounding ball-bearing 56. Should the tension of the web passing around the roller 16 decrease at one selvedge, the appropriate end of the axle 30 slides in the hole 32 to operate a pin 46 engaging a member 44 attached to the switch 42. The switches 42 are in the circuit of relays, not shown, either of which relays, when closed, energizes a reversible electric motor, not shown, which controls the inclination of one or more weft straightening rollers.