Patent GB-682549-A (GB)
Title: Apparatus for detecting inequalities of thickness in web and strand material
IPC: D06H3/10
Filed: 1950-06-01
Abstract: 682,549. Finishing and inspecting fabrics; knitting machines; gauging thickness of paper. ROBBINS MILLS, Inc. June 1, 1950. [Dec. 2, 1949] No. 13706/50. Classes 42 (i), 42 (ii), 74 (ii) and 96. [Also in Groups IX and XVI] Apparatus for detecting inequalities of thickness of a strand, e.g. yarn passing to a knitting machine, or of a web of material, e.g. cloth or paper, comprises a support in contact with which the material is traversed, one or more rings of electrically conducting material loosely suspended on another support arranged so that the ring or rings contact one side of the material, an electric circuit, one or more electrical contacts and a source of electrical energy in the circuit, whereby inequalities of thickness of the material will cause movement of the ring or one or more of the rings about the point or points of suspension so as to engage the contact or one or more of the contacts and complete the circuit so that traverse of the material is interrupted, a stop motion is actuated or a visual or audible signal is given. As shown, Fig. 4, a fabric or paper web F being fed to a three-bowl calender passes over a support 52. A series of detecting rings 91 arranged across the width of the web hang from a support 90 in contact with the web F, support 90 being carried in bearings 81 sliding in brackets 75 and being adjustable towards and away from the web by rotating an eccentric shaft 82 engaging each bearing 81. Brackets 75 can be adjusted around supports 52. On the passage of a thick portion of web, a ring 91 is caused to swing about support 90 so as to contact a conducting wire 96, stretched across the web width between insulating pulleys 111, and operate an electric stop motion for the calender. In an alternative arrangement, web support 52 is disposed to one side and above the axis of support 90, the web passing beneath support 52 and electrical contacts 96 being disposed adjacent opposite sides of rings 91 so that the rings can make electrical contact with one or other of the contacts 96 to detect either a projection or a depression in the material. In another arrangement, Fig. 8, associated with a fabric inspection apparatus, an individual conducting wire 206 in circuit with a lamp 217 is provided in connection with each ring 191, so that when a ring is raised to contact its wire 206, the corresponding lamp 217 lights up. In a further arrangement, Fig. 13, for use with a tricot or circular knitting machine, a detecting ring 327<SP>1</SP> is carried loosely on a support 320<SP>1</SP> between collars 325<SP>1</SP> and rests in the position shown on a tensioned travelling yarn S<SP>1</SP>. On the passage of a thick portion of yarn, ring 327<SP>1</SP> swings forwardly and upwardly to contact a coiled wire conductor 330<SP>1</SP>, or if the yarn slackens or breaks ring 327<SP>1</SP> swings rearwardly to contact a similar conductor 352 ; in either case a circuit is closed to actuate an electrical stop motion or operate a warning signal such as a lamp or buzzer. In a modification, the detecting ring rests on the yarn immediately above a stationary supporting member, and acts only to detect thick yarn portions. The apparatus may include connections to a counter or marking device for marking or registering the total number of defects in a piece of material.