Patent GB-465899-A (GB)
Title: An electrically controlled stop-motion device for detecting metallic substances in fibrous materials and stopping its passage into process machinery, such as scutching, opening, carding, scribbling and like machines
IPC: D01G31/00
Filed: 1935-12-06
Abstract: 465,899. Stop-motions. MERCHANT, T. Dec. 6, 1935, No. 33825. [Class 42 (i)] [Also in Group IX] Metallic substances are detected in unwoven or unfabricated fibrous material, felt or wadding, by passing the material through a pair of rollers arranged in an electric circuit so that any metallic substances in the material will bridge the rollers, establish the circuit and stop and/or reverse the feed of the material. The circuit may control a stop-motion and/or alarm for the feed device or machine, while the rollers are preferably covered with Garnett teeth or wire cloth to penetrate the material and detect even small pieces of metal. The detector mechanism comprises rollers A, B, Fig. 1, covered with Garnett wire or wire clothing a, b, geared together by gearwheels A<1> B<1> and the bottom rollers A driven through gearwheels A<2>, A<3> from the shaft C. The rollers are mounted in bearings a<1>, b<1>, having insulating material b<2>, the gear-wheel B<1> being insulated from the shaft of the roller B. The shaft C is driven by a pulley C<1> loosely mounted thereon and having a clutch D controlled by a setting-on lever E. A casing F for the electric control gear is provided with a pivoted arm or lever G the arm g engaging the setting-on lever E and the arm g<1> engaging an arm K controlled by an electromagnet K<1>, Fig. 9. The arm K holds the lever G against the pull of the spring H which tends to pull the lever E in the direction to disengage the clutch D. The electric circuit includes the rollers A, B the electromagnet K<1>, a transformer K2, a relay coil K<3>, a bell K4 and a stop push switch K<5> connected as shown in Fig. 9. The rollers A, B are connected to terminals 3, 4. Current is supplied from the mains to terminals 1, 2 and passes to the primary terminal 5 of the transformer K<2> through one terminal 7 of the electromagnet K<1> the other terminal 8 of which is connected to the primary terminal 6 of the transformer K<2> through the secondary terminals 9, 10 of the relay coil K<3>. The secondary terminals 11, 12 of the transformer K<2> are connected to the primary terminals 13, 14 of the relay coil K<3> which are in series with the terminals 3, 4. The bell K<4> is arranged in parallel with the electromagnet K<1>. When a metallic substance comes into contact with the teeth or wires a, b of the rollers A, B and causes the terminals 3, 4 to be bridged secondary current from the transformer K<2> will pass through the relay coil K<3> which permits primary current from the mains to energize the electromagnet K<1> which then operates the arm K and moves the lever G out of engagement with the handle E and allows the spring H to move the clutch D away from the pulley C<1>. Simultaneously the bell K<4> is energized. The circuit is broken immediately thereafter to prevent any possibility of the teeth or wires becoming heated. Instead of the rollers being driven through a clutch they may be driven by a reversing motor, e.g. the feed rollers A<3>, B<3> of a Garnett machine are driven from a reversing motor L through gearing 11 .. 16, Fig. 10, so that on completion of the current through the rollers a relay is energized which reverses the motor contacts. After a predetermined number of revolutions in the reverse direction limit switch M driven by chain gearing m comes into operation to stop the motor L or to rotate it again in the forward direction. In a modification, the top roller is arranged to lift against a spring a<6>, Fig. 8, on the passage of a relatively large metallic substance.