Patent GB-1138871-A (GB)
Title: Improved quickly releasable fastening device
Inventor: GOULD GEORGE HERBERT
IPC: A44B11/25
Filed: 1965-07-16
Abstract: 1,138,871. Buckles. AIRCRAFT MATERIALS Ltd. and G. H. GOULD. 4 Oct., 1966 [16 July, 1965], No. 30366/65. Heading E2A. A quickly releasable fastening device for securing the free end portions of parachute or seat harness straps comprises a number of plungers 17 slidably mounted in a housing 10 and which are spring loaded into fastening positions therein, the plungers being independently displaceable out of the fastening positions to enable apertured lugs on the free end portions of the harness straps to be engaged thereover and jointly displaceable out of the fastening positions under the control of an operating knob 14 to release the harness lugs from the housing, and a member 33 movably mounted in the housing and spring loaded towards an operative position in which it engages in a recess 17d in each plunger to prevent the displacement of the plungers in the housing, or a driving connection between said member and said operating knob a plurality of elements 43 each spring loaded into the path of a respective plunger to prevent said plunger rising into a position in which said member can engage in the recess therein, each element being independently displaceable out of the path of its associated plunger by insertion of a said harness lug over said plunger so that said plunger can rise through the aperture in the lug. In the construction shown the member 33 is a locking plate which is carried by a sleeve 12 the sleeve being rotatable relative to a central operating member 13 which is rigidly connected to the knob 14. The locking plate is spring loaded towards its operative position by two small levers 39 which are pivotally mounted on screwed sleeves 40 extending through the housing 10 and loaded by torsion springs 41 so as to bear against straight edge parts 33b of the locking plate. The locking plate has 4 main peripheral slots 33a to receive the four plungers and two further peripheral slots 33c which co-operate with two conical studs 46 mounted in a recessed rear face of the housing 10 and projecting therefrom and which during axial movement of the locking plate co-operate with the slots 33c to cause rotation of the locking plate. The locking plate is connected to the central operating member 13 by means of two spring loaded pins 37 carried by the locking plate which engage cam slots 13a in the central operating member. The elements 43 which prevent the plungers rising consist of arms which are held in two channel shaped members 45 inset in radial slots 22c in the housing and located between adjacent slots 22 which receive the harness lugs; twin torsion springs 44 with a common leg 44a form the pivot members of the arms 43 and also bias the arms so that when the plungers are not engaged with the harness, lugs the arms are located in slots 17c in the plunger. When it is desired to engage one of the harness lugs over a respective plunger 17, the end of the harness lug is forced against an inclined face 17b of the plunger, causing the plunger to be depressed sufficiently to bring its slotted end 17c out of engagement with the respective spring loaded arms 43 and the arm then deflects the arm 43 out of the path of the plunger which is therefore able to rise into full engagement with the lug when the aperture therein is brought into register with the plunger, the rising of the plunger brings the recess 17d therein into register with an edge of the corresponding slot 33a of the locking plate and when all the harness lugs have been engaged with their respective plungers and all the recesses 17d have brought into register with the edges of the slots 33a the spring loaded levers 39 cause the locking plate to move automatically into locking engagement with all the plungers. Prior to the movement of the plungers to their harness lug engaging positions the locking plate engages against the cylindrical portions of the plungers above the recess. When the harness lugs are all engaged with their plungers and with the knob 14 in the locking position, the central operating member 13 projects from beneath the locking plate 33 and abuts a back plate assembly 23 so that any hard impact on the knob 14 is transmitted directly to the back plate; to release the harness lugs the knob 14 is first rotated clockwise through 90‹; this moves the knob 14 and the central operating member 13 away from the back plate assembly since inclined faces 25a of a cam ring 25 which is connected for rotation with the knob 14 engage rollers 15a of a ring 15 which is housed in a recess in the housing 10; the locking plate does not move during the rotation of the knob the pins 37 moving from one end to the other of their cam slots in the central operating member 13. After the completion of the 90‹ turn the knob 14 is depressed and the consequent movement of the central operating member 13 moves the locking plate 33 and hence the plungers towards the back plate assembly so releasing the harness lugs. The harness lugs are then ejected by rotation of the spring loaded arms 43 which then become positioned over the plungers. During the depression of the knob 14 and operating member 13 the conical studs 46 engage the edges of the slot 33c and cause the locking plate to rotate out of locking engagement with the recesses 17d in the locking plungers. When the knob 14 is fully depressed, a catch plate lever 24c on a cover plate 24 engages a shoulder 25b in the side of the cam ring 25 and thereby retains the knob operating member 13, locking plate 33 and plungers 17 in the retracted position against the pressure of the springs 18 which bias the plungers to the fastening positions. When it is desired to re-engage the harness lugs with the plungers the operating knob 14 is reset to its locking position by counter clockwise rotation while it is still depressed; the rotation imparts a counter clockwise rotations to the cam ring 25 and causes the catch lever 24c to disengage the cam ring; the engagement of the pins 37 in the cam slots 13a of the operating member 13 causes the locking plate 33 to rise to the harness lug engaging position; the plungers move with the locking plate 33 until they engage the spring loaded arms 43, the arms holding them slightly depressed so that the locking plate cannot enter the recesses 17d but instead engages the cylindrical walls of the plungers. At the completion of the counter clockwise locking rotation of the operating knob the cam ring by reason of its engagement with the rollers 15a in the ring 15 causes this ring to rotate through 90‹ and at the completion of the 90‹ movement a catch lever 24b moves into engagement with a face 25c of the cam ring 25 and prevents clockwise rotation of the operating knob. The harness lugs can then be inserted into the recesses 22 to engage with the plunger 17, as previously described, to depress the plungers so that the locking plate can engage in the recesses 17d; the end of the first harness lug to be inserted engages a scalloped recess in the ring 15 and rotates the ring to move the catch lever 24b out of engagement with the cam ring thus permitting clockwise rotation of the knob 14 to release the harness lugs.