No-back/offset gear box

US6231012A · kind A · utility

Inventors

• Michael J. Cacciola · Puyallup, US
• Mark Joseph Gardner · Warrington, US
• Stephen T. Steadman · Redmond, US

Key dates

• Filing date: Nov 12, 1998
• Grant date: May 15, 2001
• Expiry date: Nov 12, 2018

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F16H2035/005
• WIPO field: Mechanical elements
• WIPO sector: Mechanical engineering

Abstract

Referring to FIG. 2, disclosed is an aircraft compound no-back/offset gearbox (2) with an integral load proportional safety (no-back) brake (50). The four gears are all 16 diametral pitch, involute external spur gears with 20 degree standard pressure angles. The two gear stages are interconnected with a mechanical fuse or shearout (40) designed to fail under excess shear loads and protect components downstream of the input shaft (10) from excess torque in the event of a system jam. The shearout (40) is essentially a quill shaft with external splines at both ends and an hourglass-shaped shear neckdown in the middle. The purpose of the no-back brake (50) is to prevent air loads from causing slat movement in the event of a torque tube disconnect. Referring to Figure, the no-back consists of a set of ball ramp (22) and brake plate components connected to the gearbox's output shaft. The ball ramp device converts part of the back driving torque into the axial force required to clamp the brake stack components (30) and restrain the output shaft. In this way, the back driving torque is reacted to structure and movement of the slat is prevented.