# US 2014/0190291 A1 · Flight-control actuators having a secondary nut

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- Number: US 2014/0190291 A1
- Document ID: US20140190291A1
- Status: Published application
- Kind: A1
- Application number: 13/980,782
- Filed: 2012-01-19
- Published: 2014-07-10
- Earliest claimed: 2011-01-19
- Assignees: Goodrich Actuation Systems Limited
- Inventors: Raphael Medina
- Web page: https://patentgrep.com/patent/US20140190291A1

## CPC

- F16H 25/22: with balls, rollers, or similar members between the co-operating parts; Elements essential to the use of such members
- B64C 13/341: {having duplication or stand-by provisions}
- F16H 25/205: {comprising alternate power paths, e.g. for fail safe back-up}
- F16H 25/2472: {Safety nuts}
- Y10T 74/18576: including screw and nut
- F16H: GEARING
- B64C: AEROPLANES; HELICOPTERS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The invention relates to a flight-control actuator comprising a control screw (1) that engages with a primary nut (2), the actuator also comprising a secondary nut (5) that engages with the control screw in the event the primary nut fails. The primary nut and the secondary nut are remote from one another, the secondary nut moving substantially along a portion of the screw that is usually not fitted with the primary nut.

## Claims

### Claim 1

Flight-control actuator comprising a control screw that engages with a primary nut, the actuator also comprising a secondary nut that engages with the control screw in the event of failure of the primary nut, characterised in that the primary nut and the secondary nut are remote from one another and move essentially along two distinct zones of the screw.

### Claim 2 (depends on 1)

Flight-control actuator according to claim 1, characterised in that the secondary nut moves essentially along a portion of the screw that is not habitually engaged by the primary nut.

### Claim 3 (depends on 1)

Flight-control actuator according to claim 1, characterised in that the primary nut and the secondary nut are connected to the plane that is to be controlled by means of a single attachment flange.

### Claim 4 (depends on 1)

Flight-control actuator according to claim 1, characterised in that the primary nut and the secondary nut are connected to the plane that is to be controlled by means of distinct attachment means.

### Claim 5 (depends on 1)

Flight-control actuator according to claim 1, characterised in that the primary nut is embodied here as a ball circulating nut, while the secondary nut is a friction nut.

### Claim 6 (depends on 1, 2, 3, 4, 5)

Flight-control actuator according to one of claims 1 to 5, characterised in that:
the primary nut and the secondary nut are remote from one another and move essentially along two distinct zones of the screw, and
the two distinct zones of the screw are separated by a blocking system, configured to prevent a fracture appearing at one of said zones of the screw from propagating towards the other of said zones.

### Claim 7 (depends on 6)

Flight-control actuator according to claim 6, wherein the blocking system is a groove or a discontinuity in the control screw.

### Claim 8 (depends on 1, 2, 3, 4, 5)

Flight-control actuator according to one of claims 1 to 5, characterised in that the control screw is made up of:
a first control screw which cooperates with the primary nut, and
a second control screw which is distinct from the first control screw and which cooperates with the secondary nut,
the primary nut moving along the first screw, and the secondary nut moving along the second screw.

### Claim 9 (depends on 1, 2, 3, 4, 5, 6, 7, 8)

Flight-control actuator according to one of claims 1 to 8, characterised in that the control screw is selected from among a threaded screw, a ball screw or a roller screw.

### Claim 10

Horizontal flight-control actuator, characterised in that it comprises an actuator according to any one of the preceding claims.