Sorting conveyor control system

• US 3,880,298 A
• Filed: 07/24/1972
• Issued: 04/29/1975
• Est. Priority Date: 07/24/1972
• Status: Expired due to Term

• Current Assignee: Andrew B. Huttula, James D. Habegger
• Original Assignee: Andrew B. Huttula, James D. Habegger
• Inventors: Habegger, James D., Huttula, Andrew B.
• Primary Examiner(s): Spar, Robert J.
• Assistant Examiner(s): Johnson, R. B.
• Application Number:
  US05/274,566
• Time in Patent Office: 1,009 Days
• Field of Search: 214/11R,11 198/208,38 33/147L,147N,134A
• US Class Current: 198/349.95
• CPC Class Codes: B65G 47/50 according to destination signals stored in separate systems

Abstract

An endless loop sorting conveyor includes a plurality of article carrying trays which receive randomly fed articles from one or more induction stations and selectively discharge the articles onto a plurality of discharge chutes adjacent the conveyor such that articles on trays identified by destination codes for the articles thereon will be sorted by discharging the articles onto correspondingly identified discharge chutes. A control circuit includes memory means for storing article destination codes and corresponding chute identification codes and receives tray position information from sensors positioned along the conveyor such that the instantaneous article carrying tray position with respect to the discharge chutes can be predicted. The control circuit actuates mechanisms for discharging articles onto discharge chutes when the trays are in alignment with correspondingly addressed chutes. A compensation control corrects for length variations of the sorting conveyor loop to insure accurate discharge of articles onto the chutes.

Claims

1. A system for sorting articles inducted onto trays of a conveyor which pass a plurality of individual discharge chutes positioned adjacent the conveyor by diverting articles from preselected trays when in alignment with desired discharge chutes, said system comprising:

a conveyor segmented into a plurality of discharge zones along its length, wherein each discharge zone includes a plurality of alternately spaced first and second discharge locations, said conveyor including a plurality of trays and also including a conveyor drive member for transporting said trays along said conveyor and wherein means are provided for detecting changes in at least one dimension of said conveyor drive member which is subject to change during use;

a plurality of uniquely identified discharge chutes Positioned along said conveyor in alignment with said plurality of discharge locations;

a single set of sensors for providing timing signals, said set comprising a plurality of spaced tray detectors each positioned at a reference location along a single segment of the conveyor and spaced a predetermined distance from an adjacent sensor to detect trays passing thereby, means coupling each detector with a plurality of discharge locations of one of said alternately spaced first and second discharge locations such that each alternate discharge location has a plurality of associated detectors;

means for providing article destination information which identifies at least one of said uniquely identified discharge chutes for each tray having an article inducted thereon;

control means coupled to said tray detectors and to said providing means and responsive to signals from said tray detectors for periodically generating first and second divert signals in response to the detection of a tray passing first and second detectors, respectively, of said set for simultaneously diverting articles from article carrying trays when in alignment with correspondingly identified discharge chutes at first and second discharge locations in preselected discharge zones at the time said first and second detectors, respectively, are actuated by said tray, and means for applying signals representative of detected dimension changes to said control means to selectively change the time of diverting of articles by developing said first and second divert signals upon detection of a tray by different detectors of said set to compensate for dimension variations of said drive member; and

divert means positioned at each discharge location and coupled to said control means, said divert means responsive to divert signals from said control means to divert an article from a tray at said discharge location onto a discharge chute.

2. The apparatus as defined in claim 1 wherein at least some of said discharge locations have oppositely positioned discharge chutes and wherein said control means selectively develops divert signals for each of said discharge locations to actuate said divert means positioned at said discharge locations to divert an article onto a select one of said discharge chutes at said discharge location.

3. The apparatus as defined in claim 1 wherein said control means develops divert signals for said first discharge locations of preselected discharge zones when predetermined ones of said plurality of tray detectors detect a tray passing thereby and develops divert signals for said second discharge locations of preselected discharge zones when predetermined other tray detectors detect a tray passing thereby.

4. The apparatus as defined in claim 3 wherein said control means includes computing means for predicting the alignment of trays with corresponding discharge chutes and for controlling the generation of said divert signals for said discharge locations to occur in timed coordination with the predicted time of alignment when one of said tray detectors detects a tray passing thereby.

5. The apparatus as defined in claim 4 wherein said conveyor is an endless loop conveyor and said drive member comprises an endless loop to which said trays are coupled and which is supported between a pair of rotatable end members, one of which is lineally movable, and wherein said system includes means for shifting the position of said movable member to maintain relatively constant tension on said endless loop as its length varies during use.

6. A system for sorting articles inducted onto trays of a conveyor which pass a plurality of individual discharge chutes positioned adjacent the conveyor by diverting articles from preselected trays when in alignment with desired discharge chutes, said system comprising:

an endless loop conveyor segmented into a plurality of discharge zones along its length, wherein each zone includes a plurality of alternately spaced first and seCond discharge locations said conveyor including an endless loop conveyor drive member to which said trays are coupled for transporting said trays along said discharge chutes said endless loop drive member supported between a pair of rotatable end members, one of which is lineally movable, and wherein said system includes means for shifting the position of said movable member to maintain relatively constant tension on said endless loop as its length varies during use and wherein means are provided for detecting changes in at least one dimension of said conveyor drive member which is subject to change during use and for applying signals representative of detected dimension changes to said control means to selectively change the diverting of articles in a manner to compensate for dimension variations of said drive member;

a plurality of uniquely identified discharge chutes positioned along said conveyor in alignment with said plurality of discharge locations;

a plurality of sensing means positioned at predetermined reference locations along the conveyor to detect trays passing thereby;

means for providing article destination information which identifies at least one of said uniquely identified discharge chutes for each tray having an article inducted thereon;

control means coupled to said sensing means and to said providing means for generating first and second divert signals for article carrying trays in alignment with correspondingly identified discharge chutes at first and second discharge locations in preselected discharge zones when first and second ones of said sensing means are actuated wherein said control means develops divert signals for said first discharge locations of preselected discharge zones when predetermined ones of said plurality of sensing means detect a tray passing thereby and develops divert signals for said second discharge locations of preselected discharge zones when predetermined other sensing means detect a tray passing thereby, and wherein said control means includes computing means for predicting the alignment of trays with corresponding discharge chutes and for controlling the generation of said divert signals for said discharge locations to occur in timed coordination with the predicted time of alignment when one of said sensing means detects a tray passing thereby;

divert means positioned at each discharge location and coupled to said control means, said divert means responsive to divert signals from said control means to divert an article from a tray at said discharge location onto a discharge chute; and

wherein said means for shifting the position of said movable end member comprises a fixed framework and a carriage on which said end member is rotatably coupled slidably positioned on said fixed framework; and

wherein said detecting means comprises a generator including cam means positioned on one of said movable carriage or said fixed frame and follower means positioned on the other of said movable carriage or fixed frame to generate signals in response to the travel of said movable carriage on said fixed frame as the length of said endless loop varies during use.

7. The apparatus as defined in claim 6 wherein said endless loop is a chain having a plurality of links and wherein said follower means comprises a plurality of limit switches selectively actuated by said cam means to develop chain length representative signals therefrom.