1. Field of the Invention
The invention relates to the field of separation systems for missile payload fairings and the like and, in particular, to a separation system that reduces shock loads in the missile and payload.
2. Description of Related Art
The typical systems for mechanically securing segments of a payload fairing together use explosively actuated fasteners, such as explosive bolts and the like. Another type of explosive actuated system uses a metal coupling to join the segments of the fairing together. A tubular member is positioned next to or within the coupling. Upon ignition, the explosive expands the tubular member, which in turn fractures the coupling. Such a system is disclosed in U.S. Pat. No. 5,443,492 xe2x80x9cPayload Housing And Assembly Joint For A Launch Vehiclexe2x80x9d by A. L. Chan, et al.
However, pyrotechnic fasteners and the like, while well proven, can not be tested prior to use, thus must be assembled with great care. This makes them generally expensive to manufacture. Special storage areas must be set aside for any device containing explosives. They are always subject to inadvertent actuation, and, therefore, handled with great care. Additionally, they are particularly subject to ignition by electromagnetic interference (EMI) and thus must be protected by EMI shielding devices, which also raises the cost. Another disadvantage is that, due to the fact that the explosive charge can be ignited by exposure to high temperature, they have a limited environmental temperature range. One of the most important disadvantages is that upon actuation, most generate significant shock loads, which can damage nearby equipment.
Thus in order to eliminate the above disadvantages non-pyrotechnic designs have emerged. For example, U.S. Pat. No. 5,046,426 xe2x80x9cSequential Structural Separation Systemxe2x80x9d by G. J. Julien, et al. uses a sequence of wires or foil strips attached by their ends to the edges of adjoining segments, thus securing them together. But when heated the wires or foils melt allowing the segments to separate. By varying the lengths of the wires or foils in sequence, such that they fuse in sequence. The disadvantage of this system is that every wire or foil must be separately connected to an electrical circuit. This adds complexity. In addition complete testing of this device is not possible because, once actuated the foil strips are destroyed.
Thus, it is a primary object of the invention to provide a system for securing the segments of a structure together and to provide for separation of the segments.
It is another primary object of the invention to provide a system for securing the segments of a structure together and to provide for the separation of the segments in a sequential manner.
It is a further object of the invention to provide a system for securing the segments of a structure together and to provide for separation of the segments without significant shock loads being introduced into the structure.
It is a still further object of the invention to provide a system for securing the segments of a structure together and to provide for separation of the segments that can be tested prior to use and reset.
The invention is a separation system for releasably securing first and second structural members together along mating edges thereof. For example, the segments of a launch vehicle fairing used to protect the payload until orbit is reached. In detail, the invention includes a plurality of latches with each latch including a male portion mounted in proximity to the edge of the first structural member and a female portion mounted on the second structural member in proximity to the edge thereof. A locking device is mounted on the second structural member in proximity to the edge thereof, movable from a locked position securing the male portion to the female portion to a second position unlocking the male portion from the female portion. An actuation device is provided for sequentially moving the locking device of each latch from the first position to the second position, unlocking the male portions from the female portions of the plurality of latches.
The female portion of the latch includes a slot having inward directed protrusions at the entrance thereto. The male portion includes a pair of arms having first and second ends, the first ends pined to the first structure within the slot and the second ends having tangs. The arms are rotatable about the first end from a first position wherein the tangs are engaged with the protrusions of the female portion to a second position wherein the tangs are out of engagement with the protrusions. The locking means includes a pin movably mounted in the second structure, the pin movable from a first position wedged between the arms locking the arms in the first position, to a second position retracted from the arms such that they can move to their second position. A detente system is used to releasably hold the pin in either the first or second position.
The device for sequentially activating the locking devices includes a guide track mounted in the second structure in proximity to the edge thereof perpendicular to the movement of the pin. A cam block is slidably mounted in the guide track and includes a curved cam groove that exits from the first end a first distance from the edge of the second structure and a second end at second distance from the edge of the first structure, with the second distance greater than the first distance. The pin includes a cam follower protruding out one side thereof. A motor actuated cable system moves the cam block along the guide track such that as the cam follower of the pin enters the first end of the cam groove and exits from the second moving the pin from the first position to the second position allowing the male portion of the latch to disengage from the female portion.
The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.