Browse Prior Art Database

Automatic Cartridge Tape Library Grip Mechanism

IP.com Disclosure Number: IPCOM000105529D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-20
Document File: 4 page(s) / 134K

Publishing Venue

IBM

Related People

Ellis, J: AUTHOR

Abstract

Disclosed is a design for a simple, reliable grip mechanism for handling tape cartridges in an automatic library.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 48% of the total text.

Automatic Cartridge Tape Library Grip Mechanism

      Disclosed is a design for a simple, reliable grip mechanism for
handling tape cartridges in an automatic library.

      The gripper grasps 3480 cartridges by means of a stationary
finger and a pivoting thumb.  The thumb is forced closed (+ theta-Y)
by grip springs.  The thumb is pivoted open (-theta-Y) by energizing
a solenoid.  The thumb and finger are as thin as material strength
will allow to permit insertion between closely-spaced cartridges in
library storage cells.  The thumb has a ridge on its lower surface to
engage the label recess in top of the cartridge.  The finger has an
elastomeric pad on its interior surface to increase friction with the
cartridge (Figure).

      The grip mechanism employs an eject bar which translates in the
X direction guided by linear bearings and biased forward (+X) by 2
eject springs.  The eject bar serves three purposes:

1.  A sensor sensing the forward end-of-travel of the bar notifies
    the gripper controller that a cartridge is present.
2.  A second sensor sensing the rear position of the eject bar
    notifies the gripper controller that the cartridge is fully
    seated in the grip and gives the OK to close the grip.
3.  When the gripper arrives at its destination with a cartridge, the
    grip opens and the spring-loaded eject bar ejects the cartridge
    from the grip.

      The grip open sensor is triggered by a flag on the thumb.  This
sensor confirms to the grip controller that the thumb is rotated
fully in the (-theta-Y) direction and to proceed to move the grip
mechanism forward (+X) over a cartridge.

      The grip assembly is supported by two parallel shafts extending
from the grip mount.  The grip assembly rides on linear bearings and
is permitted to translate (+/-X) on the compliance shafts.  The grip
assembly is biased forward (+X) by 2 compliance springs.  This causes
stops fixed to the compliance shafts to be held against seats on the
grip body and against the compliance sensor.  This sensor senses the
gap between the stop and the grip body to notify the grip controller
that the grip mechanism has stopped forward (+X) motion.

The purpose of this is twofold:

1.  If the grip unexpectedly encounters an obstacle when moving in
    the +X direction, the sensor notifies the grip controller,

    allowing it to stop forward motion and if required, back-up (-X)
    and re-try.
2.  During the "teach" process of the library, the accessor can move
    the grip forward (+X) until the grip encounters its target,
    establishing the depth-of-reach parameter to the accessor
    controller.

      The solenoid is fixed to the solenoid mount.  The solenoid and
mount are permitted to rotate (+/-theta-Y) on pins and bushings held
in journals in the grip body.  The purpose of this is to permit the
solenoid body to conform to the rotational motion of the thumb
attached to t...