Object detection apparatus and method

• US 6,064,629 A
• Filed: 12/15/1998
• Issued: 05/16/2000
• Est. Priority Date: 09/01/1989
• Status: Expired due to Fees

• Current Assignee: Quantronix Incorporated
• Original Assignee: Quantronix Incorporated
• Inventors: Kennington, Robert L., Stringer, Bradley J.
• Primary Examiner(s): Pihulic, Daniel T.
• Application Number:
  US09/212,191
• Time in Patent Office: 518 Days
• Field of Search: 367/99, 367/128, 702/159, 342/54, 342/52, 356/379
• US Class Current: 367/128
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/04 specially adapted for measuring length or width of objects while moving
• CPC Class Codes: G01B 17/00 Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
• CPC Class Codes: G07B 2017/00685 Measuring the dimensions of mailpieces

Abstract

A method and apparatus for ensuring accuracy of weight measurement of objects on a conveyor and providing security against pilferage or miscoding of the objects. A series of sensors such as photocells linked to a process control unit sense passage of objects to respectively activate a scale and cubing system associated with the conveyor, to release an additional object for weighing and cubing, to sense overlong objects exceeding the length of the scale, and to detect when an object has been stolen or otherwise removed (as by falling off) the conveyor between various locations through the use of programmed timing "windows" between the various sensors. If an object does not trigger a sensor within the window measured from passage past a preceding sensor, an error message is generated.

Claims

1. An apparatus for detecting a location of at least one object moving on a conveyor, comprising:

a conveyor including at least one segment comprising a scale segment and at least another segment comprising a cubing system segment;

a plurality of object presence detecting sensors longitudinally spaced along a length of the conveyor, at least one sensor of the plurality located between the scale segment and the cubing system segment, at least another sensor of the plurality located before the scale and cubing system segments and at least one other sensor of the plurality located after the scale and cubing system segments, taken in a direction of conveyor movement; and

a process control unit to which each of the plurality of sensors is operably linked.

2. The apparatus of claim 1, wherein a first sensor before the scale segment is adapted to trigger the process control unit to activate the scale segment upon complete passage of an object past that sensor.

3. The apparatus of claim 2, wherein a second sensor is adapted to trigger the process control unit to deactivate the scale segment prior to passage of an object therefrom.

4. The apparatus of claim 3, wherein the process control unit is adapted to recognize an erroneous weight reading by the scale segment responsive to substantially simultaneous sensing of an object by the first and second sensors.

5. The apparatus of claim 4, further including a third sensor adapted to indicate entry of an object into the cubing system segment.

6. The apparatus of claim 5, wherein the entry indication by the third sensor is adapted to initiate release of another object into the scale segment.

7. The apparatus of claim 6, further including a fourth sensor adapted to sense a presence of an object and activate at least one function of the cubing system segment through the process control unit.

8. The apparatus of claim 7, further including a fifth sensor adapted to sense passage of an object from the scale segment and cubing system segment.

9. The apparatus of claim 1, wherein the process control unit is programmed to recognize, based upon conveyor speed, when an object has failed to pass between two sensors.

10. The apparatus of claim 1, wherein the plurality of sensors comprises through-beam photocells.

11. A method of detecting at least one moving object, comprising:

moving an object along a path at a determinable rate of speed;

providing sensors to detect a presence of the object at a plurality of longitudinally-spaced locations along the path;

determining a time of passage of the object between at least two locations of the plurality based upon the determinable rate of speed; and

recognizing when arrival of the object is overdue at a second of the at least two locations after passage from a first of the at least two locations.

12. The method of claim 11, further including weighing the object after complete passage thereof past a sensor is detected at one of the plurality of locations.

13. The method of claim 12, further including determining a weight is in error by detecting a substantially simultaneous presence of the object at two locations of the plurality.

14. The method of claim 11, further including determining at least one dimension of the object responsive to detection of the object at a location of the plurality.

15. The method of claim 11, further including releasing a second object for movement responsive to detection of a presence of the object at a location of the plurality.

16. The method of claim 11, wherein the plurality of sensors comprises photocells and presence of an object is detected by interruption of a through-beam of a photocell.