Patent GB-1491156-A (GB)
Title: Apparatus for trimming carrots
IPC: A23N15/04
Filed: 1975-04-29
Abstract: 1491156 Cutting heads off carrots M R TAMKIN 14 April 1976 [29 April 1975] 17819/75 Heading A4C [Also in Division G1] Apparatus for cutting the heads off carrots comprises a horizontal wheel conveyer 1 which passes through a cutting station 5, a paddle 10  operated by a pneumatic ram pushing each carrot individually off the conveyer and passed one of blades 6 or 7 depending on its direction of taper, the cut-off head falling into shoot 13 and the carrot body falling into shoot 12 between the blades. A second pair of blades 8, 9 are located on the opposite side of the conveyer so that the following carrot can be cut as the paddle returns to its initial position. One or more addition conveyers 1' and cutting stations may be provided concentric with the first conveyer and utilize the same drive. The direction of taper of each carrot is determined by a sensor 4 receiving light from a source 3. The sensor may be a charge coupled device 30 with 256 photo-sensitive elements scanned on every pulse from a master clock source 34 synchronized with the speed of rotation of the conveyer. A video output from device 30 on line 32 is fed to a black level clamp and shaping circuit 38 where it is converted into a two level digital output. When the lowermost elements of the device 30 are shadowed, as detected by counter 40, this is indicative of the presence of a carrot and a signal from the counter through memory 44 will produce an output, at AND gate 48, called a beginning of carrot signal (BOC). At the end of a carrot a similar signal (EOC) will be produced at the output of AND gate 50. To avoid errors caused by misshapen carrots the BOC and EOC signals will only be produced if the carrot or lack of carrot is detected for four consecutive scans. Counter 52 by first counting up and then down the illuminated elements of device 30 and producing a net count can determining the direction of taper of a carrot, e.g. if the carrot is head first the number of illuminated elements in the second scan will exceed that in the first so that the net count will be negative. The control of counter 52 is by counter 54, the latter being connected to the clock source. The occurance times of the BOC and EOC signals are stored in three sets of two registers 56, 58, 56', 58', 56", 58" through a switch matrix 60. As soon as the direction of taper of a carrot is determined one of the signals in a register set will be erased and the other used to actuate solenoid valve 17 to operate paddle 10. For example if the carrot is head first the EOC signal will be erased and the BOC signal used to push the carrot passed either of blades 7 or 9. The master clock source is synchronized with the conveyer by providing four equally spaced radial arms on the latter which intersect a light source. A signal from a light detector is applied to a discriminator circuit which also receives input from an oscillator. If the conveyer and oscillator are synchronized a predetermined number of pulses will occur during each 90 degrees of rotation of the conveyer wheel. Any deviation will be fed back to the oscillator which is adjusted so that two divided outputs, which serve as the master clock signals, are synchronized with the conveyer wheel speed.