Patent GB-190804860-A (GB)
Title: Improvements in Automatic Weighing Scales.
Inventor: THOMPSON WILLIAM PHILLIPS
Filed: 1908-03-03
Granted: 1909-04-05
Abstract: 4860. Thompson, W. P., [Bond Scale Co.]. March 3. Automatic-feed weighers.-A machine for automatically weighing-out definite quantities of material has means for varying the time of cut-off to allow for the quantity of material in suspension between the valves and the receptacle and to eliminate inaccuracy arising from the momentum of the falling material. The scale platform b, Figs. 1 and 3, is connected to the scale-beam 21 by a rod, 22, The material passes through a shoot 3 on opposite sides for the reception of two cut-off gates 7, 12. The gate 7, which is pierced with a dribble hole 9, is keyed to a shaft 8 and is connected by a rod 10 with an automatic door-check 19, which closes the gate slowly when it is freed. The smaller gate 12 is arranged to cover the hole 9 when the gates are closed, and is secured to an arm 11 keyed to a rotating shaft 46. An elbow 16 forming part of the arm 7<1> of the gate 7 has a circular face 15, which, when the gate 7 is opened, engages the end 14 of a rearward extension of the arm 11 and opens the gate 12. The shaft 8 has also secured to it an arm 23, Fig. 5, carrying at its end a spring-controlled dog 24, which engages a detent 25 on a post 26 pivoted to a bracket on the plate 2. A knuckle 30 and a finger 31 are both fixed to the post 26 and the finger engages a notch 32 on the upper edge of a trip latch 33, Fig. 9, which is pivoted on a plate 34 and has a shoulder 35 which rests on the pivoted armature 36 of an electro-magnet 40. When the magnet circuit is closed, the latch falls and releases the finger. The post 26 then revolves under the pull of the dog 24, the detent 25 releases the dog, and the shaft 8 turns and closes the gate 7. An elbow 29 secured to the shaft 8 engages the knuckle 30 as the gate closes and re-sets the tripping-gear, the magnet circuit having been broken. The wires in the circuit are joined to contact-pieces 42, 43, Fig. 5, and an arm 45 carried by the arm 23 closes this part of the circuit when the gate is open and opens it as the gate closes. The smaller gate 12 is closed by a spring coiled round the shaft 46, and is held and released by a tripping-device similar to that described. The latches may be re'eased manually by a V-shaped lever 63, which is pivoted on the shaft 46 and carries depending fingers 64 which move the magnet armatures when a cord attached to the lever is pulled. The battery 64<1>, Figs. 1 and 3, has one pole connected to the frame of the machine and the other to the contact-pieces from which wires lead to a contact-box 66 carried below the scale beam. A lever 67, Fig. 16, pivoted to this box extends under the scale and is lifted as the beam rises by a rod 70. This rod is pivoted to two parallel links 71, 72, which in turn are pivoted to the frame of the box, and is lifted by a spring 80 the tension of which may be adjusted by moving a pointer over a graduated face. The links carry a contact-piece 73 which makes contact with another piece 74 as the beam rises and releases the gate 12. Another contact-piece 75 pivoted to the frame of the box makes contact wich a piece 77 as the beam commences to rise and releases the gate 7. The contact 75 is lifted by a spring 78 the tension of which is adjusted by means of a nut 79. By altering the tension of the spring 80, the time of closing of the gate 12 may be adjusted to compensate for the amount of material in suspension beneath the gates and the receptacle. When weighing freely-flowing heavy material the gate 7 is caused to close earlier by increasing the tension of the spring 80. The door-check 19 closes the gate 7 slowly, thus preventing any rebounding of the scale beam by reason of the sudden release from pressure caused by the momentum of the falling material.