Patent GB-1050456-A (GB)
IPC: B64C27/50
Abstract: 1,050,456. Helicopter rotors. BOEING CO. Nov. 22, 1963 [Dec. 4, 1962], No. 46181/63. Heading B7W. [Also in Division E2] A releasable coupling comprises a first coupling means 21 having an opening therein with a lateral entrance communicating with the opening and directed outwardly therefrom, a second coupling means 35 engageable with the first coupling means including locking means 40 for locking said second coupling means in engagement with the first coupling means, the locking means being movable between a first position to permit insertion of the locking means through the lateral entrance into the opening and a second locked position holding the locking means in locked relationship within the opening, means 43 for moving the locking means between the first and second positions and a releasable locking means 32 engageable with the means for moving the locking means to prevent movement of the locking means from the locked position within the opening. In the construction shown the first coupling means has two flanges 22, 23 each of which has a centrally located bore 24, 25 therethrough which are aligned to define the opening the flanges having vertically aligned outwardly divergent entrance slots 26, 27 extending outwardly through the flanges from the bores 24 and 25 and defining the lateral entrance; the second coupling means includes an arm 17 having a bearing 38 in which the locking means, which as shown is a pin, is rotatably mounted. The pin 40 has two pairs or arcuate locking surfaces 83 and two pairs of flat surfaces 42, 42<SP>1</SP> joining the arcuate surfaces, the flat surfaces of each pair being parallel to enable the pin to be passed through the entrance slots 26, 27 into the bores 24, 25; the surfaces in the bores engaged by the pin are formed by upper and lower bushings 28, 29 which are mounted on the flanges 22 and 23 and which extend through the bores. When the pin is passed through the entrance openings rotation causes its arcuate surfaces to engage the surfaces of the bushings to prevent withdrawal of the pin. The upper bushing 28 is provided with a pair of arcuate cam portions 56, 57 and the lower bushing 29 also has a pair of cam portions 90, 90<SP>1</SP>, not shown. The means 43 for rotating the pin is a handle which includes upper and lower arm portions 74, 75. The pin is also provided with a cam follower 44 which projects diametrically through the pin in a slot 86 which is elongated axially of the pin and the cam follower is biased toward the arm portion 74 of the handle by a pack of spring washers. When the pin is passed into the bushings 28, 29 through the entrance openings and rotated, the cam follower engages the lower cam portions 90, 90<SP>1</SP> and the arm portion 74 of the handle engages the upper cam portions 56, 57. Hence in the locking position of the pin the spring pack is compressed and tends to maintain the pin in the locking position. In addition the upper bushing 28 carries the releasable locking means 32 which is in the form of a spring arm having a notch 67 which in the locking position of the pin is engaged by a tapered end 79 of the arm portion 74 to retain the handle 43 and hence the pin in the locking position. The arm 32 must be moved manually before the handle 43 can be rotated to release the pin. As described, the coupling connects a damper to a foldable rotor blade assembly of a rotary wing aircraft the arm 17 being formed as an integral part of the damper and the flanges 22, 23 being an integral part of a pitch bearing housing 11; the damper is pivotally connected to a rotor blade and thus extends between the rotor blade and the pitch bearing housing.