# US 2016/0258385 A1 · Dual-Cam Bellcrank Mechanism

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2016/0258385 A1
- Document ID: US20160258385A1
- Status: Published application
- Kind: A1
- Application number: 14/635,625
- Filed: 2015-03-02
- Published: 2016-09-08
- Earliest claimed: 2015-03-02
- Assignees: The Boeing Company
- Applicants: The Boeing Company
- Inventors: Alex C. Lumbab
- Web page: https://patentgrep.com/patent/US20160258385A1

## CPC

- F02K 1/15: Control or regulation
- B05B 1/04: in flat form, e.g. fan-like, sheet-like
- F02K 1/763: {with actuating systems or actuating devices; Arrangement of actuators for thrust reversers}
- F16H 25/18: for conveying or interconverting oscillating or reciprocating motions
- F05D 2260/56: using cams or eccentrics
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00)
- B05B: SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES (spray-mixers with nozzles B01F25/72; processes for applying liquids or other fluent materials to surfaces by spraying B05D)
- F16H: GEARING
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION

## Abstract

A method and system for imparting a linear motion to a flexible shaft is disclosed. The system includes a bellcrank having a first arm, a second arm, and a first pivot pin therebetween. The system further includes an actuating device coupled to the first arm and configured to apply a force to cause the bellcrank to rotate about the first pivot pin. Still further, the system includes a second pivot pin coupled to a rod-end of the flexible shaft and further coupled to a slotted hole on the second arm. Yet still further, the system includes a follower surface on the rod-end of the flexible shaft and configured to slide on a cam surface machined on the second arm. Upon application of the force to the first arm, the flexible shaft moves in a substantially linear motion.

## Claims

### Claim 1

A system for imparting a linear motion to a flexible shaft, the system comprising:
a bellcrank having a first arm, a second arm, and a first pivot pin therebetween;
an actuating device coupled to the first arm and configured to apply a force thereto to cause the bellcrank to rotate about the first pivot pin;
a second pivot pin coupled to a rod-end of the flexible shaft and further coupled to a slotted hole on the second arm;
a follower surface on the rod-end of the flexible shaft and configured to slide on a cam surface machined on the second arm; and
wherein upon application of the force to the first arm, the flexible shaft moves in a substantially linear motion.

### Claim 2 (depends on 1)

The system of claim 1, wherein a shape of the follower surface and a shape of the cam surface are selected based at least in part on (i) a degree of rotation imparted on the bellcrank by the actuating device and (ii) a length of the first arm and a length of the second arm.

### Claim 3 (depends on 1)

The system of claim 1, wherein, when the follower surface slides on the cam surface, an interaction of the follower surface on the cam surface produces a cam reaction that counters a reaction of the second pivot pin, such that the second pivot pin moves in the substantially linear motion.

### Claim 4 (depends on 1)

The system of claim 1, wherein the slotted hole has (i) a width that substantially corresponds to a diameter of the second pivot pin and (ii) a length that is greater than the diameter of the second pivot pin.

### Claim 5 (depends on 4)

The system of claim 4, wherein the slotted hole moves laterally relative to the second pivot pin when the flexible shaft moves in the substantially linear motion.

### Claim 6 (depends on 1)

The system of claim 1, wherein the follower surface comprises a first curved shape, and wherein the cam surface comprises a second curved shape different from the first curved shape.

### Claim 7 (depends on 1)

The system of claim 1, further comprising a second follower surface on the rod-end of the flexible shaft and configured to slide on a second cam surface machined on the second arm.

### Claim 8 (depends on 1)

The system of claim 1, wherein the flexible shaft is a flexible shaft of a variable area fan nozzle (VAFN).

### Claim 9 (depends on 8)

The system of claim 8, wherein the bellcrank is configured to rotate at least between 0 and 10 degrees about the first pivot pin.

### Claim 10 (depends on 1)

The system of claim 1, wherein the flexible shaft is unsupported at the rod-end of the flexible shaft.

### Claim 11 (depends on 1)

The system of claim 1, wherein the flexible shaft comprises a metal or fiber-reinforced plastic material.

### Claim 12

A system for imparting a linear motion to a flexible shaft, the system comprising:
a bellcrank having a first arm, a second arm, and a first pivot pin therebetween;
an actuating device coupled to the first arm and configured to apply a force to cause the bellcrank to rotate about the first pivot pin;
a second pivot pin coupled to a rod-end of the flexible shaft and further coupled to a slotted hole on the second arm;
a first follower surface on the rod-end of the flexible shaft and configured to slide on a first cam surface machined on the second arm;
a second follower surface on the rod-end of the flexible shaft and configured to slide on a second cam surface machined on the second arm, wherein the second follower surface is located on an opposite side of the rod-end of the flexible shaft as the first follower surface;
wherein upon application of the force to the first arm, the flexible shaft moves in a substantially linear motion

### Claim 13 (depends on 12)

The system of claim 12, wherein a shape of the first follower surface, a shape of the first cam surface, a shape of the second follower surface, and a shape of the second cam surface are selected based at least in part on (i) a degree of rotation imparted on the bellcrank by the actuating device and (ii) a length of the first arm and a length of the second arm.

### Claim 14 (depends on 13)

The system of claim 13, wherein the bellcrank is configured to rotate at least between 0 and 10 degrees about the first pivot pin.

### Claim 15

A method for manufacturing a system comprising a bellcrank coupled to a rod-end of a flexible shaft, the bellcrank comprising a first arm, a second arm and a pivot therebetween, the method comprising:
selecting (i) a shape of a cam surface for the second arm of the bellcrank and (ii) a shape of a follower surface for the rod-end of the flexible shaft, wherein the shape of the follower surface and the shape of the cam surface are selected such that upon application of force to the first arm, the flexible shaft will move in a substantially linear motion;
machining the cam surface on the second arm of the bellcrank; and
machining the follower surface on the rod-end of the flexible shaft.

### Claim 16 (depends on 15)

The method of claim 15, wherein the shape of the cam surface and the shape of the follower surface are determined based at least in part on (a) a degree of rotation to be imparted on the bellcrank by an actuating device and (b) a length of the first arm and the second arm.

### Claim 17 (depends on 15)

The method of claim 15, further comprising providing a first pivot pin in the pivot between the first arm and the second arm.

### Claim 18 (depends on 17)

The method of claim 17, further comprising:
providing a slotted hole on the second arm; and
coupling a second pivot pin to the rod-end of the flexible shaft and to the slotted hole.

### Claim 19 (depends on 15)

The method of claim 15, further comprising:
selecting (i) a shape of a second cam surface for the second arm of the bellcrank and (ii) a shape of a second follower surface for the rod-end of the flexible shaft;
machining the second follower surface on the rod-end of the flexible shaft; and
machining the second cam surface on the second arm.

### Claim 20 (depends on 15)

The method of claim 15, wherein the flexible shaft is a flexible shaft of a variable area fan nozzle (VAFN).