US 4,697,246 AGranted

Method and apparatus for detecting the engagement of a proper number of articles

AssigneeBell & Howell Company

InventorsEdward H. Zemke, deceased, Gary L. Vandersyde, K. George Rabindran, Kenneth L. Guenther

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Abstract

Method and apparatus for detecting article engagement errors and for calibrating engagement error detection apparatus associated with a plurality of gripper arms (16) of an insertion machine (10). Gripper arms (16) at each of a plurality of insert stations S comprise a first jaw member (24) and a second jaw member (26) which selectively engage articles therebetween. Field-generating means (420) is mounted on one jaw member while a Hall Effect sensor (400) is connected on the other jaw member. The sensed flux density of the generated field is a function of the relative displacement of the first and second jaw members (24,26). A signal generated by the sensor (400) operated in a slide-by mode is related to the separation of the first jaw member (24) and second jaw member (26). If the sensor-generated signal is within predetermined limits of a stored reference signal a proper number of articles are engaged between the first and second jaw members (24,26). The reference signal is stored for each insert station S in accordance with a method and apparatus for calibrating an engagement error detector (364) associated with the station S. The engagement error detectors for a plurality of insert stations can be calibrated one-at-a-time in serial fashion or, in an alternate mode, essentially simultaneously using a master calibration switch (MCS).

Claims26

Dependent claims

A gripper arm for selectively engaging and retrieving articles from a station proximate the gripper arm, said gripper arm comprising:

a gripper arm housing having a first end and a second end, said gripper arm housing having two parallel panels which define a space therebetween;
means at the second end of said housing for securing said gripper arm to oscillating drive means;
a first jaw member proximate said first end of said gripper arm housing;
a second jaw member proximate said first end of said gripper arm housing, said second jaw member being selectively movable with respect to said first jaw member for the engagement of articles therebetween;
actuation means for selectively moving said second jaw member with respect to said first jaw member whereby articles are selectively engaged between said jaw members;
and,
means for detecting whether a proper number of articles are engaged between said first jaw member and said second jaw member of said gripper arm, said detecting means comprising:
means for creating a magnetic field, said magnetic field-creating means being mounted on one of saw jaw members;
Hall Effect sensor means for sensing the flux density of said magnetic field and for generating an output signal proportional thereto, said sensor means being mounted with respect to the other of said jaw members;
and,
biasing means for biasing said magnetic field-creating means relative to said sensor means whereby a first plane including an essentially planar surface of said magnetic field-creating means remains in a predetermined relationship with respect to a second plane including an essentially planar surface of said sensor means in a manner whereby slidable displacement occurs between said field-creating means and said sensor means as said second jaw member is moved with respect to said first jaw mcmber, said field-creating means and said sensor means being positioned in said space defined by said gripper arm housing panels and mounted relative to said jaw members in a manner whereby said output signal of said sensor means is related to the distance separating said first and second jaw members as said slidable displacement occurs.

8 more elements

A method of operating a gripper arm of an insertion machine in a manner to determine whether a proper number of articles are engaged between first and secnd jaw members comprising said gripper arm, said method comprising the steps of:

oscillating said gripper arm whereby said gripper arm approaches a hopper whereat an article is stored;
creating a magnetic field by using field-creating means, said field-creating means being mounted with respect to one of said jaw members and positioned in a space defined between two parallel panels of said gripper arm housing;
biasing said magnetic field-creating means with respect to Hall Effect sensor means, said Hall Effect sensor means also being positioned in said spaced defined by said gripper arm housing panels, said biasing occurring in a manner whereby a first plane included in an essentially planar surface of said magnetic field-creating means remains in a predetermined relationship with respect to a second plane including an essentially planar surface of said sensor means, said first and second planes being parallel to one another and whereby slidable displacement can occur between said field-creating means and said sensor;
activating actuation means whereby said second jaw member moves toward said first jaw member in a manner whereby slidable displacement occurs between said field-creating means and said sensor and whereby said hopper-stored article is engaged between said first jaw member and said second jaw member;
sensing the flux density of said magnetic field using said Hall Effect sensor means when an ariticle is engaged between said first jaw member and said second jaw member, said Hall Effect sensor means being mounted with respect to the other of said jaw members in a manner suitable for sensing any change in displacement of the jaw members relative to one another;
generating an output signal proportional to said sensed field flux density;
and,
using the magnitude of said output signal as an indication of whether a proper number of articles are engaged between said first and second jaw members.

5 more elements

Dependencies are inferred from the claim text.