Remotely actuated two stage structural latch

#This invention relates to a remotely actuated two stage structural latch and, more particularly, the invention is concerned with providing a latching device which is especially adaptable for use in supporting an aircraft canopy for flight loads and in such a manner that the aircraft canopy latch can be remotely locked or unlocked while the aircraft is on the ground or unlocked for emergency canopy ejection during flight.

#Heretofore, various devices have evolved for purposes of canopy latching including, for example, sliding latches sliding hooks, rotating hooks and various shaped bolts. These devices usually require hydraulic, pneumatic, electrical or pyrotechnic power devices to cut, shear, unlock or disengage for emergency canopy opening.

#Several disadvantages are inherent in such systems which lack the advantages of easy manual release. Because of the high forces required to open and close the canopies under load and since the sliding hook and rotating hook devices have a high degree of friction loss when operated under load, usually a powered device is required to operate the system for normal ground operations and explosive devices are usually necessary to either cut or shear the latch supporting pin for emergency canopy release.

#FIG. 1 is a plan view which diagramatically illustrates the apparatus according to the invention in the fully latched position;

#FIG. 2 is an end view of the apparatus of FIG. 1;

#FIG. 3 is a plan view of the apparatus which diagramatically illustrates the pull up capabilities in a partially latched position; and

#Referring now to the drawings wherein like reference numerals refer to like elements in the several views, the body to be fastened is shown as a support housing 13 with the pin 15 thereon for attachment to the clevis pin 17. An S shaped hook 19 provides the only structural load carrying member connecting housing 13, pin 15 and clevis pin 17. The load between clevis pin 17 and pin 15 is in line in hook 19 therefore no rotating forces exist to release or unlock hook 19. Inadvertent unlock of hook 19 is secured by an over center alignment of link 21 and link 23 at pin 25 and the pressure is maintained from safety spring 27.

#A two stage hook 19 movement is required to connect or release the tie between pin 15 and clevis pin 17. The first stage hook 19 movement is to rotate hook 19 about link 29 at pin 31 to create clearances 33 and 35, thus releasing the structural tie between pin 15 and clevis pin 17 as shown in FIG. 3. The second stage hook 19 movement is to lock hook 19 to link 29 at pin 31 and rotate hook 19 and link 29 around shaft 37 to create clearance gap 39 such that housing 13, pin 15 and clevis pin 17 can be separated as shown in FIG. 4. Housing 13, pin 15 and clevis pin 17 can be forced apart when hook 19 and pin 17 make contact at surface 39 and hook 19 is rotated around shaft 37 in the direction of the arrow 41.

#Pushing, pulling or rotating the rod, cable or tube 43 causes the drive wheel or arm 45 to rotate. Drive wheel 45 is spline locked to shaft 37. Link 23 is spline locked to shaft 37. Rotation of shaft 37 rotates link 23 around shaft 37. Link 21 is pinned to link 23 at pin 25, and moves with link 23 and pivots around pin 25. Link 21 is pinned to hook 19 and pivots around pin 47. Link 29 is pinned to hook 19 and is free to pivot at pin 31. Link 29 is pinned to shaft 37. Link 29 can pivot freely around shaft 37. Link 29 has a stop 49 to contact pin 15. Link 21 is free to pivot on pin 47 until stop 51 on hook 19 restricts rotation. Link 29 is free to rotate around shaft 37 until stop 49 contacts pin 15 and restricts rotation.