Browse Prior Art Database

Pawl Return Latch Mechanism

IP.com Disclosure Number: IPCOM000088988D
Original Publication Date: 1977-Sep-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Parks, HM: AUTHOR

Abstract

Track-stepping ratchet noise produced during a return operation is eliminated with a frictionally restrained return latch mechanism.

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Pawl Return Latch Mechanism

Track-stepping ratchet noise produced during a return operation is eliminated with a frictionally restrained return latch mechanism.

In a prior art magnetic card deck, a read/write/erase head is carried by carrier 1 (Fig. 1). Carrier 1, which is normally biased to the left, is made up of integral pawl 2, arm 16 and lever 17.

Pawl 2 is maintained in engagement with toothed rack 3 by spring 4. Spring 4 is connected to stud 10 and lever 17. For track stepping of the head to the left, carrier 1 is momentarily rotated about pivot 5 in the direction of arrow 6 and then released to permit engagement of pawl 2 with the next tooth on rack 3. For return of the head to the right to a starting position, an overriding force is applied in the direction of arrow 7, and pawl 2 ratchets over the teeth of rack 3.

ln order to eliminate the ratchet noise created during the return operation, carrier 1 is provided with tang 8, and a rotatable latch mechanism 9 is connected to stud 10. Mechanism 9 has a latch cutout 11, and carries a friction pad 15 which is maintained in contact with rack 3.

In Fig. 2 there are shown, from left to right, the various positions assumed by pawl 2, tang 8, and mechanism 9. In the first position, pawl 2 is in engagement with rack 3. At this time, mechanism 9 is restrained in the direction of arrow 12 by pad 15. The second position illustrates the beginning of the operation for returning carrier 1 to the right. Pawl 2 is brought...