Patent GB-901807-A (GB)
Title: A sorting machine
IPC: B07C5/18
Filed: 1959-12-22
Abstract: 901,807. Sorting by weighing. ENEVOLDSEN, S.V. Dec. 22, 1959 [Dec. 23, 1958], No. 43469/59. Class 143.  A sorting machine has at least one two-armed weighing lever on one arm of which weights are deposited or removed by rotating cams, the other arm supporting a pivoted member engageable by the teeth of a ratchet wheel which is rotated in synchronism with the weight placing cams and which operates when the weighing lever tilts to turn the said member to activate a control mechanism determining the destination of an object being weighed. The said pivoted member carries a pawl which, when the weigh bar tilts, is pushed by a tooth of the ratchet wheel to engage a second pivoted member which operates the control mechanism. As shown in Figs. 1 and 2, the weighing lever 1 carries at one end a weight carrier 32 loaded by a fixed counterweight 33 and held against a stop by a spring-loaded rod 15 until released by the action of a cam 13 on the rod 15. A supplementary weight 17, normally also loading the carrier 32, is liftable by a rod 16 acted on by a cam 14. The cams 13, 14 are mounted on a shaft 2 which also carries a ratchet wheel 26 operating the control mechanism. The control mechanism comprises three rods 9, 10, 11 vertically reciprocable respectively by cams 6, 7, 8 on shaft 2. Two balls 20 serve, whenever one of the rods 9 to 11 is lowered by its cam, to lock the adjacent rod or rods in their upper position by engagement with constrictions 18 in the rods. In addition, the rods 10, 11 may be held in their upper position by means of the inter-engagement of cams 21 on the upper ends of the rods withholding cams 22 on a pivoted lever 23. This inter-engagement is released when the weighing lever tilts under load, an arm 24 pivotally suspended from the scale pan 5 and terminating in a pawl 25 being pushed by a tooth of the ratchet wheel 26 to tilt the lever 23. The control function of the mechanism is performed by the rod 11 whose upper end acts on a lever 27 whose end 28 is engageable with the cam 29: when the rod 11 is in its lower position this cam is locked against rotation and holds closed a counterweighted pivoted gate 3. In use, articles 30 are fed singly to the scale pan 5 on a conveyer 4 and the rotation of the shaft 2 controls the following sequence of operations. The rod 15 is first raised by its cam to release the weighing lever, loaded with the weights 33 and 17. If the article is over-weight this causes pawl 25 of the arm 24 to be lowered into the path of tooth T 0  on ratchet wheel 26 and cause the tilting of lever 23. At this stage rods 9 and 11 are raised by their cams but not rod 10, which, disengaged from its holding cam 22, holds and locks the other rods in their upper position so that the gate 3 is not locked. The article, when discharged from the scale pan, will subsequently be rejected as it passes the gate. If the article is of correct weight, it fails to turn the scale before tooth T 0  passes the arm 24 but will turn before tooth T n  arrives as a result of the removal of the supplementary weight 17 by its cam 14. In this case, rod 11 falls when the tooth T n  hits pawl 25, thereby locking the gate 3. If the article is underweight, there is no turn of the scale and rod 11 remains suspended from its holding cam 22 and the unlocked gate 3 is turned by the article which is thus rejected from the conveyer path. The ball 20 between the rods 10 and 11 may be omitted and the descent of rod 10 made to operate a switch initiating a visual or audible alarm so that over-weight objects are indicated but not rejected. The cams 13, 14 on the one hand and the cams and ratchet wheel of the control mechanism on the other may be on synchronously driven shafts perpendicular to the weighing lever and carrying further cams for the simultaneous operation of other weighers set up parallel to the one shown. In the form shown in Figs. 7 and 8, the ratchet wheel 26 has six teeth and there are five supplementary weights 45 corresponding to the weight 17 of the first embodiment. A plurality of lamellae 40 are conveyed in an endless path over the weigher, each lamella carrying an end plate 42 fitted with a roller 43 engageable with a trackway 39. When the scale tilts, the pivoted lever 24 is pushed by a tooth of the ratchet wheel 26 to operate pivoted lever 34 to release a spring- urged rod 37 which closes a gap in the track 39. The rollers of those lamellae which, at this stage, have passed the weigher will have entered the gap and tilted their lamellae into a position where they pass above an object on the scale pan 5, whereas the subsequent lamellae will be untilted and the first such untilted lamella pushes the weighed object over the pivoted gates 46. When the position shown in Fig. 7 is reached, all the gates 46 are unlatched and that supporting the object falls and directs the object to a take-away path corresponding to its weight.