Browse Prior Art Database

Bidirectional Clutch Spring

IP.com Disclosure Number: IPCOM000040020D
Original Publication Date: 1987-Sep-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 82K

Publishing Venue

IBM

Related People

Feinstein, P: AUTHOR [+2]

Abstract

An arrangement is described which prevents potential damage to an automatic sheet feed for a printer. Fig. 1 is a side perspective view of the sheet feed showing the arrangement. Figs. 2 and 3 show the operation. The sheet feed is an entirely mechanical, snap-on mechanism that will feed cut-sheet paper on demand. To accomplish this, a 180-degree reverse index of the platen is required to activate a sheet feed load cycle. After this is complete, the printer drives the platen in the forward direction which feeds a sheet of paper to the printer. This function is done automatically; however, it can also be done manually by depressing the reverse index button on the printer control panel.

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Bidirectional Clutch Spring

An arrangement is described which prevents potential damage to an automatic sheet feed for a printer. Fig. 1 is a side perspective view of the sheet feed showing the arrangement. Figs. 2 and 3 show the operation. The sheet feed is an entirely mechanical, snap-on mechanism that will feed cut-sheet paper on demand. To accomplish this, a 180-degree reverse index of the platen is required to activate a sheet feed load cycle. After this is complete, the printer drives the platen in the forward direction which feeds a sheet of paper to the printer. This function is done automatically; however, it can also be done manually by depressing the reverse index button on the printer control panel. If the reverse

(Image Omitted)

index button is depressed longer than is required to activate the cycle, damage to the gear drive and mechanism could result. Therefore, the actuation means must be designed to prevent damage in this situation. The unique clutch spring (Fig. 1) provides the required clutch actuation as well as preventing potential damage to the mechanism by providing overrun potential in both directions. A detailed sheet feed clutch operation follows: When the printer requires a cut sheet of paper, it automatically performs a 180-degree reverse index of the platen (not shown). The platen is geared to the rotation of the idler gear 1. When driving clockwise, the idler gear 1 is coupled to the trip lever 3 by the action of the clutch spring 2. The clutch spring 2 fits over hubs 8 on both the idler gear 1 and the trip lever 3 and tightens on both hubs when the idler gear 1 is driven clockwise, as shown. The hub on the idler gear 1 is slightly smaller in diameter than the hub on the trip lever 3, which prevents unacceptable backlash in the coupling of the two parts. As the idler gear 1 continues to turn in the clockwise direction, it rotates the trip lever 3 until it contacts the clutch latch 4, rotating the clutch latch in a clockwise direction until it unlatches the spring-loaded drive roller clutch gear 5 by clearing the latching surface 9 on the gear 5. After the drive roller gear 5 is unlatched, it rotates in a clockwise direction, as shown, driven by a leaf spring (not shown) biased shaft 7 to which the gear 5 is attached. The drive roller gear 5 rotates clockwise until it contacts the idler gear 1. The drive roller gear 5 is free to rotate clockwise due to a removed section of teeth 6, which provides a clearance between the drive roller gear 5 and the idler gear 1 before the drive rol...