Apparatus and method for positioning objects/mailpieces

• US 7,778,728 B2
• Filed: 07/13/2006
• Issued: 08/17/2010
• Est. Priority Date: 07/13/2006
• Status: Expired due to Fees

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Stemmle, Denis J.
• Primary Examiner(s): Crawford; Gene
• Assistant Examiner(s): BURGESS, RAMYA PRAKASAM
• Application Number:
  US11/487,202
• Publication Number:
  US 20080015735A1
• Time in Patent Office: 1,496 Days
• Field of Search: 209/584, 209/583, 209/900, 209/922, 209/933, 700/228, 700/224
• US Class Current: 700/228
• CPC Class Codes: B07C 1/00 Measures preceding sorting according to destination
• CPC Class Codes: B65G 43/08 Control devices operated by article or material being fed, conveyed or discharged and controlling the discharging devices B65G47/42

Abstract

An apparatus and method for positioning objects at a desired reference position, including a sensor for determining the length of each object/mailpiece from a leading to a trailing edge, a transport mechanism having a positionable drive element for transporting the object/mailpiece, and a controller or processor for controlling the position of the drive element to release the object/mailpiece at a desired reference position. The described embodiments of the invention relate to positioning an object/mailpiece in a clamp assembly of a mixed mail sorter. The jaws of the clamp assembly are separated to receive the object/mailpiece by a pair of spiral cams. The spiral cams interpose and engage tabs of each jaw to open and close the clamp assembly as they concomitantly effect translation of the clamp assembly linearly past the positioning apparatus. The apparatus and method ensures predictable conveyance and release of objects/mailpieces while being manipulated by automated handling equipment.

Claims

1. An apparatus for positioning objects at a desired reference position, comprising:

a sensor for determining the length of each object from a leading to a trailing edge thereof and issuing signals indicative of length;

a transport mechanism for transporting the object, the transport mechanism including a positionable drive element, and

a processor, responsive to the length signal, for issuing a position signal to the positionable drive element, the drive element operative to release the object upon reaching the desired reference position.

2. The apparatus according to claim 1 wherein the transport mechanism comprises a constant velocity transport mechanism disposed upstream of a variable velocity transport mechanism for conveying the objects to the desired reference position.

3. The apparatus according to claim 1 wherein the length sensor records the time difference between the leading and trailing edges of each object passing a reference point.

4. The apparatus according to claim 3 wherein the length sensor includes at least one optical sensor for detecting the time difference between leading and trailing edges of each object.

5. The apparatus according to claim 1 wherein the transport mechanism comprises at least one drive belt in combination with at least one roller to define a nip for conveying each object.

6. The apparatus according to claim 5 wherein the positionable drive element includes an actuator for linearly displacing the roller, thereby varying the point of object release.

7. The apparatus according to claim 2 wherein the constant velocity transport mechanism moves the object at a transport velocity, and wherein the variable velocity transport mechanism reduces the transport velocity prior to release of the object from the positionable drive element.

8. The apparatus according to claim 1 wherein:

the transport mechanism further comprises;

at least one drive belt and the positionable drive element of the transport mechanism includes a roller to define a nip for conveying each object;

an actuator for linearly displacing the roller, thereby varying the point of object release.

9. A system for transporting and positioning mailpieces of variable size into a clamp assembly, comprising:

a drive mechanism including a pair of rotating spiral cams engaging jaws of the clamp assembly, the spiral cams effecting separation and closure of the clamp assembly jaws;

a mailpiece length sensor for determining the length of each mailpiece from a leading to a trailing edge thereof and issuing a signal indicative of the length of each mailpiece;

a transport mechanism for transporting the mailpiece toward the clamp assembly, the transport mechanism including a positionable drive element,

a processor, responsive to the length signal, for issuing a position signal to the positionable drive element, the drive element operative to move in response to the position signal and release the mailpiece to a desired reference position within the jaws of the clamp assembly.

10. The system according to claim 9 wherein the clamp assembly defines a gravitational centerline and wherein the desired reference position relates to substantial alignment of the area centroid of each mailpiece with the gravitational centerline of the respective clamp assembly.

11. The system according to claim 9 wherein the clamp assembly includes separation tabs formed along a peripheral edge of each clamp assembly jaw and wherein the spiral cam defines cam surfaces interposing the tabs such that rotation of the cam surfaces effects opening and closure of the clamp assembly jaws.

12. The system according to claim 11 wherein rotation of the cam surfaces effects linear translation of the clamp assembly along the length of the spiral cam drive mechanism.

13. The system according to claim 9 wherein cam surfaces define a pitch dimension therebetween which varies in magnitude such that the clamp assembly jaws are spread at a first axial position along the spiral cams to accept a mailpiece and are closed at a second axial position to secure the mailpiece within the clamp assembly.

14. The system according to claim 9 further comprising a constant velocity transport mechanism disposed upstream of a variable velocity transport mechanism for conveying the mailpieces to the desired reference position.

15. The system according to claim 9 wherein the length sensor records the time difference between the leading and trailing edges of each mailpiece passing a reference point.

16. The system according to claim 9 wherein the length sensor includes at least one optical sensor for detecting the time difference between leading and trailing edges of each mailpiece.

17. The system according to claim 14 wherein the constant velocity transport mechanism moves the object at a transport velocity, and wherein the variable velocity transport mechanism reduces the transport velocity prior release of the object by the positionable drive element.

18. The system according to claim 17 wherein the positionable drive element includes an actuator for displacing the roller in a direction parallel to the transport direction, thereby varying the point of mailpiece release.

19. A method for positioning an object to a reference position, the object having a leading and trailing edge, the method comprising:

transporting the object;

measuring a length dimension between the leading and trailing edges of the object during transport;

calculating a desired position for a positionable drive element as a function of said measuring of the length dimension of the object;

moving the positionable drive element to the desired position to release the object upon the object reaching the desired reference position.

20. The method according to claim 19 wherein the object is transported at a transport velocity and further comprises:

decreasing the transport velocity of the object prior to release of the object by the positionable drive element.

21. The method according to claim 19 wherein the object defines an area centroid and further comprises positioning the object such that the area centroid is aligned with respect to the reference position.

22. The method according to claim 19 further comprising:

providing a clamp assembly having a pair of separable jaws;

opening the jaws of the clamp assembly to receive the object;

closing the jaws of the clamp assembly to secure the object therebetween upon release of the object by the positionable drive element.

23. A method for transporting and positioning mailpieces of variable length dimension into a clamp assembly, the method comprising:

feeding mailpieces to a transport mechanism;

transporting the mailpieces;

measuring a length dimension between a leading and trailing edge of each mailpiece during transport;

providing a plurality of clamp assemblies each having a pair of separable jaws;

separating the jaws of each clamp assembly to receive each mailpiece;

calculating a desired position for a positionable drive element;

moving the positionable drive element to the desired position to release the mailpiece upon reaching the desired reference position.

24. The method according to claim 23 wherein the mailpiece is transported at a transport velocity and further comprises:

decreasing the transport velocity of the mailpiece prior to the release by the positionable drive element.

25. The method according to claim 23 wherein the mailpiece defines an area centroid and further comprises positioning the mailpiece such that the area centroid is aligned with respect to the reference position.

26. The method according to claim 23 wherein each mailpiece is fed to the transport mechanism by an automated delivery system.

27. The method according to claim 23 wherein each mailpiece is fed to the transport mechanism by an operator assisted delivery system.

28. The method according the claim 23 wherein some mailpieces are fed to the transport mechanism by an automated delivery system and other mailpieces are fed to the transport mechanism by an operator-assisted delivery system.

29. An apparatus for positioning objects at a desired reference position, comprising:

a transport mechanism for transporting objects in succession lengthwise along an object transport path;

the transport mechanism comprising;

a positionable drive element;

a mechanism to position the positionable drive element selectively with respect to the object transport path in response to a position signal;

a sensor for (1) determining object length from a leading edge to a trailing edge of each the object as each the object is transported along the object transport path, and (2) issuing an object length signal indicative the object length;

a processor, responsive to the object length signal, for issuing the position signal to the positionable drive element to position the positionable drive element at a position as a function of the object length to release the object upon reaching the desired reference position.

30. An apparatus comprising:

a transport mechanism for transporting objects in succession lengthwise along an object transport path;

a drive mechanism positioned to receive the objects from the transport mechanism and to drive the objects in succession along a direction transverse to the lengths of the objects with each of the objects being maintained in desired reference position while being driven by the drive mechanism;

the transport mechanism comprising;

a positionable drive element;

a mechanism to position the positionable drive element selectively with respect to the object transport path in response to a position signal;

a sensor for (1) determining object length from a leading edge to a trailing edge of each the object as each the object is transported along the object transport path, and (2) issuing an object length signal indicative the object length;

a processor, responsive to the object length signal, for issuing the position signal to the positionable drive element to position the positionable drive element at a position as a function of the object length to release the object upon reaching the desired reference position to be driven by the drive mechanism.

31. The apparatus according to claim 30, wherein:

the desired reference position for each of the objects is the geometric center of each of the objects in relation to the driving direction of the drive mechanism.

32. The apparatus according to claim 30, wherein:

the desired reference position for each of the objects is the geometric center of each of the objects being aligned relative to the driving direction of the drive mechanism.