Patent GB-875797-A (GB)
Title: Improvements relating to the grading of articles, particularly eggs, according to weight
Inventor: LAWSON CLIFFORD WILLIAM
IPC: A01K43/00
Filed: 1957-06-25
Abstract: 875,797. Grading eggs by weight. BRECKNELL DOLMAN & ROGERS Ltd. June 24, 1958 [June 25, 1957; May 15, 1958], Nos. 20045/57 and 15618/58. Class 143 [Also in Groups XVII and XXX] Eggs, or other articles, to be graded according to weight alone, are progressed in single file along an ordered path, during which each egg is weighed without arresting its movement or disturbing the order of flow, and are subsequently discharged from the path into the appropriate one of a number of weight groupings by means controlled by a record of the weights memorised automatically at the time of weighing. General description. After a candling test, the eggs are fed manually side-on,with their pointed ends all in the same direction, on to a conveyer A, Fig. 1, which carries them in single file on to successive rotating scale pans 5b, Fig. 3 of a weighing station B whereat they are carried through each of four weighing positions WI . . .  W4 corresponding to large, standard, medium and small weight gradings. Overweight eggs are discharged into a tray K before the weighing positions are reached. According to the weight of the egg in each scale pan, the scale co-operates with a grading cam 11, Fig. 6, at the appropriate one the of four positions W1...W4 and operates a corresponding switch S1 ... S4, Fig. 2 controlling solenoids M1 ... M4 respectively allocated one to each of the four discs 50 of a memory device C. After passing through the four weighing positions each scale pan is tipped to discharge its egg on to a transfer device D which turns the egg on end, pointed end downwards, and deposits it on to a pocketed conveyer F carrying the eggs across four take-off conveyers P1 ... P4. The discharge of the eggs from the conveyer F into Keyes tray V on the appropriate take-off conveyer is effected by distributer units N1 ... N4 under the control of the memory device C and in accordance with the memorised weights of the eggs. Weighing station B comprises a continuously rotating table 19, Fig. 3, carrying about twenty scale pans 5b each pivotally mounted on the end of a weigh beam 4 which is in turn pivoted on a pin 6 to a bracket 3 on the table 19. When a scale pan reaches that weighing position Wl . . . W4 whereat its tilt causes a rear extension 10 of its beam 4 to ride up on the fixed grading cam 11, Fig. 6, the beam 4 is further tilted to depress the arm 1B of a spring-loaded bell crank lever 1 thereby causing the other arm 1A thereof to release a catch 7 pivoted on the pin 6. At the same time, the beam extension 10 moves a lever 25 to operate the plunger 27 of a weight position switch, say S4. When the extension 10 has moved clear of the grading cam 11, the bell crank 1 is moved by its spring 12 to raise the weigh beam 4 into engagement with a stop 17, in which position any operation of succeeding weigh position switches is avoided. On reaching the position adjacent the transfer device D a tail 5a on the scale pan 5b engages a tip-out cam 15a causing the scale pan to deposit the egg into a holder 101, Fig. 9, of the device D, the beam 4 having been lowered against the action of spring 12 by engagement of the extension 10 with a fixed cam 11a. At the same time, a cam 15 pivots catch 7 so that when the beam 4 is released by cam 11a and returns to its rest position, the nose 7A of the catch 7 engages the arm 1A of the bell-crank 1 to hold it out of operation. The memory device C comprises four coaxial discs, one for each weighing position, rotated in synchronism with the weighing turntable 19, each disc, such as C1, Fig. 7, having a series of trip levers 57 pivoted around its periphery. Each time the switch S1 ... S4 of the associated weighing position is operated, a stationary solenoid 53 (M1 . . . M4) is energized to rock an armature 54 and cause a roller 56 thereon to depress the adjacent leading end 57A of a trip lever 57, whereupon a catch lever 58 engages in a notch in the trailing end 57B of the trip lever to hold it proud of the disc periphery ready to actuate a series of switches El ... E6 adjustably mounted adjacent to the disc periphery. The switches E1 ... E6 are positioned so that they are actuated by the trip lever 57 slightly in advance of the time when the egg which caused, via switch S1 ...S4 and solenoid Ml . . . 4, the cocking of the trip lever is vertically above one of the six-in-line cells of a row in a Keyes tray on the appropriate conveyer P1 . . . P4. The positioning of the switches is adjustable individually and collectively to suit different types of collecting tray. Any trip lever which has been cocked is reset after passing the switches E1 ... E6 by engagement of a fixed stop 64 with a tail member 58A of the catch lever 58. In a modified form of memory disc (Figs. 18- 20, not shown) the trip levers are replaced by a series of pins extending through holes around the disc periphery parallel with the disc axis, each pin being displaceable axially in the hole by operation of the associated solenoid to effect subsequent operation of the switches E1 ... E6. The transfer device D, Fig. 9, comprises a turntable 100 carrying a series of egg holders 101 each with an associated clamp member 124 which is spring loaded to the egg clamping position, but is operable by a plunger 120 and a fixed cam 126A to be opened when the associated holder reaches the egg discharge position over the conveyer F, and to remain open until another egg is received in the holder from the weighing station B. Each holder is pivotally mounted in a bracket 103 on the turntable and carries a pinion 106 meshed with a quadrant 108 which is carried by a pivoted rocker arm 109. In operation, as each holder 101 receives an egg from the weighing station B and is carried round by the turntable 100, the clamp member 124 moves to the egg clamping position and a roller 112 on the rocker arm 109 rides around a ring cam 113 which rotates the rocker arm and thereby the quadrant 108, to rotate the holder 101 from the horizontal position to a vertical discharge position. On reaching this position the clamp member 124 is operated to release the egg which then drops, pointed end downwards, into a pocket 150 of the, distributing conveyer F. The distributing conveyer F, Figs. 10 and 11, comprises a pair of parallel endless chains 153, 154 supported along their upper run on guide rails 155, 156. The cups 150 are each in two parts 150A, 150B supported on transverse pivot pins 151, 152 respectively, which are carried by links of the endless chains, the pin 151 carrying a trip lever 157 at one end and a forked lever 158 at the other. The fork 158A of lever 158 engages a pin 160 projecting from a triangular plate 159 which is fixed to the pivot pin 152, and a spring 164 extends between the pin 152 and the trip lever 157 to bias the pocket halves together sufficiently to hold an egg. To provide positive support when the egg first drops into the pocket a roller 162 on the plate 159 bears on a shelf 163 carried by the guide rail 156. Discharge of the egg from each pocket 150 is effected over the appropriate takeoff conveyer P1 ... P4 by a pin 180 which is projected into the path of the trip lever 157 by distributer units under the control of the memory device switches E1 ... E6, the consequential rocking of lever 157 operating through the forked lever 158 and pin 160 to open the pocket halves and drop the egg into the waiting cell of the Keyes tray. The distributer units, comprise four banks N1 ... N4 (one for each weighing position) each of six solenoids G1 ... G6 and six associated sequence switches R1...R6. Because each cocked trip lever 57 of each disc of the memory device operates all the six switches El ... E6, and thereby primes all the six associated solenoids G1 . . . G6, the sequence switches R1 ... R6 are necessary to ensure that only that solenoid is energized appropriate to the next empty cell in the waiting row of the Keyes tray on the underlying take-off conveyer. Figs. 12 and 13 show a distributer unit N1 as a casing 175 housing the six solenoids G1 ... G6 each of which when energised operates a bell-crank lever 177 to project a pin 180, carried on rod 178, into the path of the trip lever 157 of the oncoming conveyer pocket 150. Operation of the bell crank lever 177 effects rocking of a lever 182 to close a pair of contacts 186, 189 comprising that sequence switch Rl . . . R6 associated with the next succeeding solenoid. This switch is held on by an arm 190C of a catch lever 190 engaging a step 182B of the lever 182. When the solenoid, say G2, is de-energized by passage of the trip lever 57 beyond the associated switch E2, the bell-crank lever 177 is thrown back, by a return spring 195 on the rod 178, with sufficient momentum to engage an arm 190A of the catch lever 190 and thereby release the catch lever arm 190C from the lever 182 and allow opening of the switch contacts 186, 189 of that sequence switch R2 controlling the solenoid (G2) just de-energized. To effect this, as shown in Fig. 13, each catch lever 190 comprises a boss 190B having one arm 190A associated with the bell-crank lever 177 of one solenoid, say G2, and the arm 190C associated with the lever 182 of the sequence switch R2 which is operated when the preceding solenoid, G1, is energized. The catch lever 190 associated with the end solenoids G1, G6 is in two parts each pinned to a coupling shaft 193 on which the bosses 190B of the other levers 190 are loosely mounted. To allow for that memory device trip lever 57 which has effected, through switch E6, energization of solenoid G6 with consequential priming of solenoid G1, to pass beyond switch E1 and thereby avoid incorrect operation of solenoid G1, a delay solenoid is coupled with solenoid G6 to open the circuit of solenoid G1 for the necessary time. The take-off conveyers P1 ... P4 are mounted side by side below, and at right angles to, the conveyer F, and are driven by a common shaft 200, Figs. 14, 15, which rotates cont