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Browse Prior Art Database

Variable Torque Counterbalance Mechanism

IP.com Disclosure Number: IPCOM000096123D
Original Publication Date: 1964-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 46K

Publishing Venue

IBM

Related People

Billings, RA: AUTHOR [+2]

Abstract

Cover 1 is hinged to frame 2 by hinge 3. Sector plate 4 is pivoted to the side of 2 by projecting stud 5. Right angle tab 6, integral with 4, rides in slotted bracket 7 attached to 1. When 1 is in the closed position as shown, its weight exerts a counterclockwise torque on 4. Such torque is greater than the relatively small clockwise torque exerted on 4 by expanded tension spring 8 acting in the direction of centerline f through the short moment arm c. The cover thus stays closed.

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Variable Torque Counterbalance Mechanism

Cover 1 is hinged to frame 2 by hinge 3. Sector plate 4 is pivoted to the side of 2 by projecting stud 5. Right angle tab 6, integral with 4, rides in slotted bracket 7 attached to 1. When 1 is in the closed position as shown, its weight exerts a counterclockwise torque on 4. Such torque is greater than the relatively small clockwise torque exerted on 4 by expanded tension spring 8 acting in the direction of centerline f through the short moment arm c. The cover thus stays closed.

As 1 is lifted through an angle of approximately 45 degrees, 4 rotates through angle alpha causing the centerline of 8 to rotate to position f'. During this initial span of movement, 8 contracts only a small amount while the moment arm through which it acts on 4 increases many times its original length to the length
d. This results in a rapid increase in the clockwise torque on 4, which after 1 is lifted only a few degrees, produces a positive lifting action on 1. Grooved guide wheel 9 stabilizes 4 during its movement.

As 1 passes through the 45 degree point and continues toward the vertical, 4 rotates through angle beta, causing the centerline of 8 to rotate to position f". During this latter span of movement 8 contracts a large amount while the moment arm through which it acts on 4 increases only a small amount, resulting in a decrease in the clockwise torque on 4. This equalizes the opposing torques on 4 and allows the operator to bring 1 to a...