Sorting conveyor

Claim 2

Sorting apparatus including a support surface to receive objects to be sorted, means to move received objects to a point of selective discharge from the support surface, means to produce said selective discharge, an indicator movable to objects supported on the surface to indicate the position of an object to be sorted in a particular way by said selective discharge, means to co-operate with the indicator to record the position of the indicator and the proximity of the indicator to said recorded position, means to generate a signal to identify the position to be recorded, means responsive to the recorded position and to the action of the means to move the objects to operate said selective discharge means to appropriately sort the object on discharge from the surface, and including means responsive to the record of the proximity of the indicator to said position to generate a signal representing the size of the object whose position is indicated, said means to produce selective discharge being responsive to said object size signal to adjust the suit the size of an object to be discharged.

Claim 3

Apparatus according to claim 1 in which the indicator includes means to generate a signal and the means to co-operate with the indicator includes electronic circuit means to compare the generated signal collected by each of a plurality of pick-up means spaced under the support surface with a time-varying signal to determine by their coincidence the pick-up means nearest to the indicator postion.

Claim 4

Apparatus according to claim 2 in which the time-varying signal is a ramp changing in value towards the picked-up signal itself changing in the opposite sense as the indicator position is approached.

Claim 5

Apparatus according to claim 3 in which the change is linear and in synchronism with a scan of all the pick-up means.

Claim 6

Apparatus according to claim 2 in which the comparison is made separately along crossing directions below the support surface.

Claim 7

Apparatus according to claim 5 in which the directions are orthogonal along and across the direction of movement of the objects.

Claim 8

Apparatus according to claim 5 in which there are two directions both inclined to said direction of movement.

Claim 9

Apparatus according to claim 2 in which the electronic circuit means to compare the time-varying and picked-up signals is effective to compare the time-varying signal with each picked up signal in turn.

Claim 10

Apparatus according to claim 2 in which the electronic circuit means to compare the time-varying and picked-up signals is effective to compare the time-varying signal with all the picked-up signals at one time.

Claim 11

Apparatus according to claim 2 including means to protect the action of the apparatus from electrical interference including a further pick-up means under the support to respond to electrical interference incident on the apparatus to produce a signal to inhibit the transfer of the result of the comparison of the collected generated signal.

Claim 12

Apparatus according to claim 2 in which the identity of the pick-up means determined on the coincidence of the signals is retained in an electronic circuit latch to record the identified position.

Claim 13

Apparatus according to claim 2 in which the identity of the pick-up means determined by the comparator means is encoded as a multibit binary word for use by the selective discharge control means.

Claim 14

Apparatus according to claim 2 in which the means to co-operate with the indicator includes furthr electronic circuit means to assess the size of the generated signal used to determine the pick-up means nearest to the indicator position.

Claim 15

Apparatus according to claim 13 in which the size of the generated signal is assessed by comparison of a further time-varying signal with a signal derived from the time-lapse before the coincidence of the first ramp signal and the generated signal.

Claim 16

Apparatus according to claim 14 in which the further signal is an exponential ramp signal.

Claim 17

Apparatus according to claim 14 in which the time-lapse derived signal is a stepwise varying voltage.

Claim 18

Apparatus according to claim 14 in which the further signal is non-linear.

Claim 19

Apparatus according to claim 1 including means to protect the action of the apparatus from electrical interference including means to respond to electrical interference incident on the apparatus when the means to record the position co-operates with the indicator to produce a signal to inhibit the recording of the position of the indicator.

Claim 20

A sorting control appartus for a sorting station of a conveyor having at the station an array of signal pick-up coils and an indicator movable over the array to indicate a position of a conveyed object to be sorted from other conveyed objects, together with means to selectively remove an indicated object, the control apparatus including a circuit arrangement to supply a signal from each pick-up coil for each direction of the array to a comparator for comparison with a ramp waveform to identify the coil nearest to the indicator position for each said direction and record the identity of the identified coils and derive information about the proximity of the indicator position to the array corresponding to the size of the object indicated, means to respond to the movement of objects by the conveyor towards the means to remove objects selectively and respond to the indicator position represented by the identified coils of the array to provide an output to the means to remove objects selectively to cause said means to remove a conveyed object, having a position and size indicated by said indicator and then recorded, on movement of said object to the removal means.

Claim 21

A sorting control appartus for a sorting station of a conveyor having at the station an array of signal pick-up coils and an indicator movable over the array to indicate a position of a conveyed object to be sorted from other conveyed objects, together with means to selectively remove an indicated object, the control apparatus including a circuit arrangement to supply a signal from each pick-up coil for each direction of the array to a comparator for comparison with a ramp waveform to identify the coil nearest to the indicator position for each said direction and record the identity of the identified coils and derive information about the proximity of the indicator position to the array corresponding to the size of the object indicated, means to respond to the movement of objects by the conveyor towards the means to remove objects selectively and respond to the indicator position represented by the identified coils of the array to provide an output to the means to remove objects selectively to cause said means to remove a conveyed object, having a position and size indicated by said indicator and then recorded, on movement of said object to the removal means.