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Home | Alpha Telephone | Domain Names | Web Hosting | Get Traffic | xrEvidence | xrSoccer United States Patent
OUTBOARD MISSILE CONTROL SURFACE AND ACTUATOR The present invention comprises a control surface actuation system capable f disposition within a restricted volume. The present actuation system and control surface is disposed outboard of the missile due to space limitations imposed by an unusually large nozzle diameter. The system comprises four independent electro-hydraulic actuators of the push-push configuration for driving four aerodynamic control surfaces arranged in cruciform and disposed at the aft end of the missile. The actuation system arrangement allows passage of the missile through existing launchers having typical volume restraints.
Assistant Examiner: Hanley; James M. What is claimed is: 1. An externally mounted missile control system comprising: a housing formed as an extension of a dorsal fin of a missile and adapted to be secured on the external surface of the missile; a series connected hydraulic actuation system mounted in said housing in a line parallel to the axis of said missile including a dual electric motor and hydraulic pump combination; a folding control surface mounted on said housing and supported by a rotatable bearing; means for rotating said control surface connected to said hydraulic actuation system; said rotating means comprising two hydraulic pistons and cylinders connected to opposite sides of said control surface by shafts; said pistons, cylinders and shafts arranged perpendicular to the axis of said control surface bearing and said pistons and cylinders being angled with respect to each other to minimize space requirements whereby said control surface is operated in a push-push arrangement. 2. The apparatus of claim 1 wherein the hydraulic piston shafts are connected at points on said control surface bearing to rotate said control surface through a range of .+-.40.degree. . 3. The apparatus of claim 1 wherein said rotatable bearing has one end connected to said control surface and the other end has a disc portion thereon connected to said shafts. 4. The apparatus of claim 3 wherein said pistons and cylinders are arranged at an acute angle with respect to each other. 5. The apparatus of claim 1 wherein said control surface is in a first folded position during launching of said missile and in a second flight position after launch of said missile and erection means within said housing for moving said control surface from the first to the second position. 6. The apparatus of claim 1 wherein the central axis of the hydraulic cylinders lie in the same plane. STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor. BACKGROUND OF THE INVENTION This invention relates to aerodynamic control surfaces for missiles and more particularly relates to an aerodynamic control surface and actuating system which is completely external to the missile. Thrust requirements for a number of recently proposed missile systems have necessitated the use of much larger nozzles than in the past. The increased size of the nozzles results in an constricted volume in the aft end of the missile thereby preventing the use of inboard control surface actuation systems of conventional design. The increased nozzle size resulting in severely constricted volume dictates the need for an actuation system and control surface which can be mounted on the external portion of the missile and not exceed the pass-through envelope of existing launchers. Present hydraulic systems are not susceptible to exterior mounting on missiles because they take up too much space. Systems which have folding control surfaces are also available. These systems have internal hydraulic actuators not suitable for external mounting. Other folding control surface systems are mechanically operated and are not as efficient as hydraulic systems and not capable of taking high bending moment loads. The present invention overcomes these difficulties by providing an in line or series connected hydraulic actuator system. SUMMARY OF THE INVENTION The purpose of this invention is to provide a hydraulically operated actuation system which can be mounted on the exterior portion of a missile within an restricted volume while still providing a highly efficient system useful with standard restricted volume launchers. A compact control surface and actuation system capable of disposition within a restricted volume is provided by mounting a push-push hydraulic system in a line parallel to the longitudinal axis of the missile body and utilizing folding control surfaces. The system is comprised of four independent electro-hydraulic actuators of the push-push configuration for driving four aerodynamic control surfaces arranged in cruciform and disposed at the aft end of the missile. This system provides control surface movement within a normally required .+-.40.degree. limits while still conforming to the space limitations imposed by unusually large nozzle diameters. It is an object of the present invention to provide a control surface and actuation system which can be mounted on the external surface of a missile. It is a further object of the present invention to provide a control surface and actuation system which can conform to the space limitations imposed by large nozzle diameter missiles. Yet another object of the present invention is to provide a control surface and actuation system for use with large nozzle missiles which allows passage through standard launchers having typical volume restraints. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a portion of the missile showing the control surface in an erect position. FIG. 2 is an axial half-section taken through the aft end of the missile at line 2--2 and the control surface actuation system. FIG. 3 is a section taken through the aft end of and perpendicular to the longitudinal axis of the missile illustrating the control surface in the folded position. FIG. 4 is a section taken through the line 4--4 of FIG. 3 and illustrating the hydraulic actuators and mid-panel support bearing. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 2 a missile is seen generally at 1 having a nozzle throat section 3 which comprises a large proportion of the volume within the main body 5 of the missile. Recently designed missiles have a throat 3 which is greater than 60 percent of the body diameter 5. As can readily be seen at 7 the remaining volume within the main body of the missile 5 is insufficient to house an inboard control surface actuation system. The present invention provides a control surface actuation system generally indicated at 11 which is housed substantially within a spar housing 31 which is an extension of a dorsal fin 33 disposed along the main body 5 of the missile. The actuation system 11 includes push-push hydraulic actuators 13, a mid-panel support bearing 15, hydraulic servo valve 17, and an electric motor/hydraulic pump combination 19 which is arranged in series as shown. The control surface 21 surmounts the spar housing 31 and is mechanically connected with the actuation system 11 through the mid-panel support bearing 15. The support bearing 15 has a shaft portion 16 one end of which is operably joined to the control surface 21. Needle bearings 14 at the end of shaft 16 also provide movable support for control surface 21. Further, the bearing 15 has an enlarged disc portion 18 which mechanically engages piston 39 through shaft 35 of the push-push hydraulic actuators 13. In FIG. 4 the actuators 13 are seen to comprise cylinders 37 in which pistons 39 are caused to operate under the influence of the electric motor/hydraulic pump combination 19, which influence is directed through the hydraulic servo valve 17. Ports (not shown) drilled in the spar housing 31 connect the servo valve 17 to the pump combination 19 in the conventional manner. The piston shafts 35 are joined to opposite sides of enlarged disc portion 18 of the support bearing 15 and control the rotational movement of the control surface 21 within a normally required .+-.40.degree. limits. The cylinders 27 are "pidgeon-toed", i.e., angled, to keep within the restricted volume of the spar housing 31. Because of space limitations in spar housing 31 two motors were required in the electric motor/hydraulic pump combination 19. A single motor which could operate the control surface 21 under bending movements up to 4,000 lbs. and still meet the space limitations is not available. Therefore the system with dual motors on either side of the pump was devised. Positional control of the push-push hydraulic actuators 13 is accomplished through normal electro/mechanical servo arrangements (not shown) which are directed by a position feed-back potentiometer (not shown) mechanically linked to the control surface through the support bearing 15. In FIG. 3 the control surface 21 is illustrated in its folded position to permit launching through standard GMLS MK 11 or MK 13 launchers. Fin erection mechanisms associated with said launchers (not shown) provide erecting force for the control surface 21 and a lock-pin mechanism (FIG. 2) provides positive locking of the control surface 21 in the flight position. In FIG. 2 the lock-pin mechanism is seen to comprise in part, a locking pin 27 and a hinge pin 29. Locking pin 27 is forced into a locking position by a spring 28 when the control surface 21 reaches upright position. This type of erection and locking mechanism is conventional. In FIG. 3 the pass-through envelope of the standard launchers mentioned above is indicated by the phantom line 43. With the control surface 21 folded against the main body 5 the missile is in the pre-launch configuration. In operation the actuation system 11 varies the pitch angle of the movable control surface 21 which is shown in the erect position in FIG. 1. Four of these systems 11 independently drive one each of four control surfaces 21 arranged in cruciform and located at the aft end of the missile. The usual servo arrangements (not shown) operates the electric motor/hydraulic pump combination 19, which influence is directed through the hydraulic servo valve 17 to provide the pushing force on piston 39 and thereby rotate the control surface 21 to guide the flight path of the missile. Each of the control surfaces 21 and actuation systems 11 operate independently of the other to provide complete missile guidance. Control surface position is provided by a feedback potentiometer (not shown) mechanically linked to support bearing 15. Thus there has been disclosed an actuator combination disposed externally of the missile body between the missile skin and the control surface which is capable of withstanding the bending moments imposed on the control surface. The outboard actuation system described herein is seen to provide effective control surface actuation while conforming to existing launcher limitations. Obviously many modifications and variations of the present invention are possible in light of the above teachings. For U.S. patent law, rules, and procedures see MPEP. Disclaimer. Information presented on this page while believed to be reliable, is provided "as is" with no warranties of its accuracy or timeliness. For legal advice seek help of a licensed professional. |