Patent GB-1086304-A (GB)
Title: Improved quickly releasable fastening device
Inventor: GOULD GEORGE HERBERT
IPC: B64D17/32
Filed: 1964-09-18
Abstract: 1,086,304. Buckles. AIRCRAFT MATERIALS Ltd. and G. H. GOULD. Sept. 7, 1965 [Sept. 18, 1964], No.38242/64. Heading E2A. A quickly releasable fastening device for a number of apertured harness lugs comprises a housing 10 containing a number of spring loaded fastening plungers 17 to 20 adapted to be displaced independently by engagement of said lugs to permit said lugs to be attached thereto, a plunger control member 33 axially displaceable in said housing for collectively displacing said fastening plungers in the housing, an operating knob 14, a central operating plunger 13 fixed to said knob, means 13a, 37 for effecting axial displacement of said central operating plunger in said control member on rotation of said knob, a back plate assembly 23 rigidly secured to the housing and against which said central operating plunger can be brought into abutting relationship to lock said control member against displacement in the housing and means for independently preventing each fastening plunger from moving axially in said control member. In the construction shown each of the last mentioned means is a pair of spring elements 34 and each of these has a pair of arms 34a, each arm being engageable in a groove in a respective plunger, one groove being shown at 17e. Each plunger has a pin, 17b to 19b, which is slidable in an inclined bore in the plunger and which is slightly longer than the bore so that it stands proud of the face of the plunger. Each lug when entered into a corresponding radial slot in the housing, of which there are four, one for each lug, engages the end of the pin protruding from the plunger and depresses it so that the other end of the pin, which is in engagement with the arm 34a in the groove, moves the arm out of the groove and so frees the plunger so that it can be depressed by further movement of the lug up its inclined engagemerit face, until the plunger enters an aperture in the lug and is returned to its fastening position by its biassing spring 17c etc.; when it reaches its fastening position the arm 34a reenters the groove to latch the plunger to the control member. In an alternative construction (not shown) the spring elements and the pins previously described are omitted and instead each plunger is rotatable in its slot in the control member and the plunger biassing springs also serve to hold the plungers each in one angular position. Each plunger has a pair of shoulders which in the angular position prevent its movement through the slot but each plunger is also provided with a projection which is engaged by the lug when inserted into the slot 22 in the housing and this projection is off-set so that the lug rotates the plunger against the bias of the spring until the shoulders are disengaged from the slot after which the plunger is moved axially into the slot by further movement of the lug in the slot 22. In each construction the means for effecting axial displacement of said central operating plunger on rotation of said knob comprises spring loaded cam pins 37 slidably mounted in the control member and arranged to engage in respective helical cam slots 13a formed in the periphery of the operating plunger, the arrangement being such that when the knob 14 is in a locking position in which it has been rotated to its furthest extent anticlockwise, the central operating plunger 13 is in engagement with the back-plate assembly and since the cam pins 17 are at the ends of their slots nearest to the knob, the control member cannot be moved towards the back-plate assembly to release the plungers since its rotation is prevented by the plungers which in addition to engaging the control member are also housed in bores 16 in the housing. The control member cannot be moved away from the back-plate assembly since it is in engagement with the housing. Clockwise rotation by 90‹ of the operating knob, rotates the central operating plunger 13 and also causes it to move axially because of the engagement of the cam pins with the slot 13a and also because the cam ring 25 coupled to the knob 14 is in engagement with rollers 15a of the locking ring 15 which is mounted in the housing and which is prevented from rotation by the lugs engaging curved recesses. The cam ring prevents depression of the knob, central operating plunger and control member until the knob, cam ring and central operating plunger have been. rotated' through 90‹, at which time the cam surfaces of the cam ring has cleared the rollers of the locking ring. When the knob is depressed the plunger takes the operating member with it and hence the plungers, to release the lugs. When the knob has been fully depressed latch lever 24c automatically engages, under the bias of the spring, shoulder 25b of the cam ring to hold the knob &c., in the depressed condition. This latch lever is cammed out of the way when the knob is turned to locking position. The movement of the control knob and central operating plunger to locking position causes the control member 33 and the fastening plungers to rise into their lug engaging positions from which each plunger can be released individually, as previously described, when the lug is inserted into the slot 22. The rotation of the knob to locking position causes the locking ring 15 to become so positioned that the curved recesses in its periphery is out of alignment with the slot 22 in the housing and a projecting stud 24e. on catch, lever 24b then enters one of the recesses under the influence of its spring and the clever engages a face 25c of the cam ring 25 to prevent unlocking rotation of. the operating knob. Entry of each harness lug into the corresponding slot 22 causes it to engage the corresponding recess in the locking ring and this rotates the locking ring and the stud 24e and releases the catch lever 24b from the face 25c, allowing unlocking rotation of the knob In an alternative arrangement the recesses in the locking ring are aligned with the radial slots in the housing or the locking position of the knob 14. The stud 24e is in engagement with the wall of the locking ring at the side of one of the recesses and hence the catch lever 24b is held out of engagement with the cam ring; any clockwise rotation of the knob 14 causes the cam ring to rotate the locking ring via inclined faces 25a and the rollers 15a, thereby allowing the catch lever to move into engagement with the face of the cam ring 25 and so prevent further rotation; insertion of each harness lug into the corresponding slot 22 causes the lug to abut the wall of the locking ring in one of the recesses and so prevent its rotation, when the knob 14 is rotated to the unlocking position.