Extendable divergent tail pipe propulsion unit

Details Extendable divergent tail pipe propulsion unit Extendable divergent tail pipe propulsion unit

1998-06-26

2001-03-27

Casaregola, Louis J. (Department: 3746)

Power plants

Internal combustion engine with treatment or handling of...

Material from exhaust structure fed to engine intake

C239S265110

Reexamination Certificate

active

06205772

ABSTRACT:

The present invention relates to a deployable diverging part of a thruster.
The thrust from a thruster depends on the rate at which gas is ejected and on the speed at which it is ejected. To optimize the speed parameter, it is necessary to have a diverging part with an outlet that is of large diameter, particularly for a second or third stage of a multistage thruster. This leads to diverging parts that are long, which is often difficult to make compatible with the space available. One solution consists in designing a diverging part that is deployable, which is of shorter length in its initial configuration and which can be lengthened by putting one or more rings of the diverging part into place.
Deployable diverging parts are also used to match the outlet section of thruster nozzles to ambient pressure, which pressure decreases from low altitudes close to the ground to high altitudes, such that as close as possible an approximation to optimum thrust is always obtained in spite of changing altitude.
In all these cases, it must be possible to deploy the deployable portion of the diverging part in a manner that is automatic and reliable, while expending a minimum amount of energy.
Various types of deployment mechanism have been proposed for deployable diverging parts, in particular mechanisms making use of cables, of roller screws, of ball screws, of beams that can be rolled out, or of a membrane. Overall, those mechanisms are relatively bulky and give rise to a very large mass penalty, particularly for diverging parts of large diameter.
A deployment mechanism that does not present those drawbacks has already been proposed in the Applicant's U.S. Pat. No. 5,282,576. The diverging part comprises a first portion whose upstream end is connected to the end wall of the thruster and a second portion in the form of a ring that is movable between a retracted position in which it surrounds the first portion of the diverging part, and a deployed position in which it is connected to the downstream end of the first portion to extend it. The deployment mechanism comprises hinged arms each having one end connected to the ring of the diverging part, and means for actuating the arms enabling the ring of the diverging part to be displaced from its retracted position to its deployed position.
It is necessary to lock the ring of the diverging part in its deployed position in order to prevent it from returning towards its retracted position under thrust from the jet passing through it. In U.S. Pat. No. 5,282,576, that locking is achieved by an over-center or “toggle” action of the arms so as to avoid leaving the actuator means continuously active after deployment, with the operation of the deployment mechanism being reversible.
An object of the present invention is to provide a deployable diverging part of the same type as U.S. Pat. No. 5,282,576, but in which the ring is locked in the deployed position in a manner that is reliable, without requiring any special geometrical configuration for the arms, and with the deployment mechanism not being designed to be reversible.
This object is achieved by the facts that:
means are provided in distributed manner at the periphery of the downstream end of the first portion and at the periphery of the upstream end of the ring so as to enable the ring to be locked onto the downstream end of the first portion when the ring is in its deployed position; and
the deployment mechanism comprises at least four arms co-operating with the ring to form a hyperstatic assembly so that the ring can be moved without significant deformation so as to be brought to the desired position for locking automatically and completely to the first portion when it is deployed.
The deployable diverging part of the invention is thus remarkable in its combination of automatic locking of the ring of the diverging part on the first portion thereof by locking means that are distributed around their periphery, and by the hyperstatic nature of the moving assembly which makes it possible to guide the ring of the diverging part accurately to the exact deployed position required for locking to take place automatically.
Advantageously, the locking means comprise a plurality of flexible tongues co-operating with one or more corresponding recesses so as to snap into the recess(es) when the ring reaches its deployed position.
Also advantageously, releasable locking means are provided to lock the ring in its retracted position.


REFERENCES:
patent: 3526365 (1970-09-01), Paine
patent: 3561679 (1971-02-01), Lager
patent: 4169555 (1979-10-01), Crowe
patent: 4676436 (1987-06-01), Willis
patent: 5282576 (1994-02-01), Chatenet et al.
patent: 2 622 931 (1989-05-01), None
patent: 2 029 511 (1980-03-01), None

Affiliated with

Also associated with

Rating

Extendable divergent tail pipe propulsion unit does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Extendable divergent tail pipe propulsion unit, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Extendable divergent tail pipe propulsion unit will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2518613