| 摘要 |
An actuator for ejecting a store from an aircraft, with a pre-selected force vs stroke profile, is disclosed. The actuator comprises a cylinder and a fixed tubular member coupled to a source of fluid under pressure having a first array of orifices for flowing fluid into the cylinder. A piston assembly is provided, which is adapted to engage and eject the store. The iston assembly is slidably mounted within the cylinder and telescopically movable over the fixed tubular member from a first position, wherein the piston assembly covers a portion of the first array of orifices, to a second position, wherein the first array of orifices is uncovered. Typically, the pressure level of the source of fluid varies, generally as a function of the flow into the cylinder during the stroke of the piston assembly. Thus, the cross-sectional area and spacing of each of the orifices of the first array is selected to maintain a desired pre-selected pressure vs stroke profile within the cylinder upon the application of the fluid to the fixed tubular member, as the initially covered portion of the first array of orifices are uncovered during the stroke. Therefore, upon initiation of fluid flow, the first array of orifices meters the fluid into the cylinder at a rate sufficient to maintain the pre-selected pressure vs stroke profile therein. A system for varying the magnitude of the pressure vs stroke profile within the cylinder is provided, which comprises an adjustable tubular member coupled to the source of fluid, rotatably mounted in a bore within the fixed tubular member. The adjustable tubular member incorporates a second array of orifices which are in a one-to-one relationship with the first array of orifices. Preferably, an electric motor is provided to rotate the adjustable tubular member varying the overlap of the first and second array of orifices, such that the magnitude of the pre-selected pressure vs stroke profile can be varied. |
