Patent GB-1020246-A (GB)
Title: Fastening device for a vehicle safety belt
IPC: B60R22/32
Filed: 1962-12-17
Abstract: 1,020,246. Releasable fastenings. M. E. J. GENIN. Dec. 17, 1962 [Dec. 19, 1961; Oct. 16, 1962], No. 47592/62. Heading E2A. [Also in Division A3] A fastening device for a vehicle safety belt 4, comprises in combination a movable element 1, 51 or 83 co-operating with the safety belt for the purpose of securing the belt in the position of use, a resilient member as shown a spring 6, 68 or 78 continuously urging the element out of the securing position, a locking member 9, 43 or 85 normally co-operating with the element to maintain it in its position of co-operation, a movable mass 10, 17 or 64 adapted to cause the locking member to be displaced out of co-operation with the movable element in response to an abrupt change in velocity of the vehicle to allow the release of the belt and means for delaying the release of the belt for a period of time after the commencement of the velocity change. In the construction shown in Fig. 1 the movable element is a sliding bolt 1 contained in a chamber 8 of a housing and normally its end 2 is held in engagement with an opening 3 in the belt 4 against the pressure of the spring 6 by the locking member 9 which engages a flange 5. The member 9 is integral with the mass 10 contained in a second chamber 14 of the housing, the mass 10 being urged in the direction in which the member 9 engages the flange 5 of the bolt by a spring 11. The axis of the mass 10 is arranged parallel with the longitudinal axis of the vehicle and when the vehicle decelerates at more than the predetermined amount, caused for example by a crash, the mass compresses the spring 11 and the member 9 is consequently moved from engagement with the flange 5 allowing the spring 6 to withdraw the end 2 of the bolt from engagement with the opening in the belt 4. The belt is thus released. The releasing movement of the bolt 1 only takes place slowly since the chamber 5 is filled with oil and this can only pass slowly through the small gap between the peripheral face of the flange 5 and the wall of the chamber. Once the bolt has moved a certain distance however, the flange passes beyond one end of a by-pass 5a provided in the wall of the chamber and this allows the oil to flow quickly from one side of the flange 5 to the other. When the flange reaches the end of its travel in the releasing direction the member 9 can move upwarldy again and hold the flange and hence the bolt in the releasing position. The pressure of the spring 11 can be made adjustable by arranging for the cover 13 to be screw threaded to the body of the chamber 14 which contains the mass 10. The device is restored to fastening position by pulling on a rod 12 on the opposite side of the mass 10 to the member 9 and pushing the bolt against the pressure of the spring 6 towards its fastening position until the member 9 engages the lefthand side of the flange 5 as shown. In a modification, Fig. 2, the mass 17 is moved by both acceleration and deceleration above a predetermined amount, springs 19 and 20 determining the threshold values, and when the mass moves, a rod 23, which is normally held in fastening position in engagement with the flange 5 of a bolt identical with that previously described, moves downwardly under the pressure of a spring 28 immediately a projection 18 on the mass moves sufficiently to allow this movement of the rod. The bolt 1 can then move in the releasing direction as quickly as the oil filling of the chamber 8 permits. The pressures on the springs 19 and 20 are individually adjustable by means of screwed plugs 21 and 22 and the rod 23 is reset by a lever 25. In a modification of this construction the member 9 instead of bearing on the longitudinally movable mass 17 bears on a ball shaped mass which is attached to a pendulum and is freely movable in a partspherical housing. The mass is provided with a groove in its upper surface and when the pendulum moves sufficiently the end of the rod 23 can move into the groove and thus release the bolt 1 so that it can withdraw to release the safety belt. Free movement of the pendulum is prevented by a spring, the bias of which is adjustable. In a modification of this construction for controlling a plurality of safety belts movement of the rod 23 closes an electric contact and solenoids are then energized to pull members 9 away from contact with the flanges 5 of the various bolts. In another construction, Fig. 5, the movable element is a hook shaped bolt 51 loaded by a spring 68 which is pivotally mounted and which engages a ring 53 attached to the belt. The hook bolt is held in engagement with the ring 53 by a locking member 43 one end of which engages a tail 67 of the hook bolt and the other end of which rests on top of a mass in the form of a ball 64 against which it is urged by a spring 49. Deceleration beyond a predetermined amount causes the ball to move from underneath the member 43 which is then urged downwardly by the spring 49 the movement being delayed by oil in the chamber in which the member 43 is contained, the oil only being able to pass slowly between the periphery of a flange 42 and the wall of the chamber. The chamber is provided with an enlarged portion 74 at the end of the travel of the member 43 so that the oil can then flow freely between the two sides of the flange 42. In a further construction, Fig. 6, the movable element is a hook member 83 fastened into the end of a bore 76 of a chamber 75 by means of a plurality of ball locking members 85 which engage a groove in the wall of the chamber and openings in the periphery of a stem of the hook member. The balls are held in position by a rod 77a carried by a piston 77. Underneath the piston which is biased downwardly by a spring 78, the chamber contains oil and the chamber is connected by a conduit 80 to a second chamber containing a piston 89. A mass in the form of a ball 64 is held between the piston 89 and a jaw 87 since the piston 89 is urged upwardly by oil pressure caused by the spring 78 passing the piston 77 downwardly. When deceleration removes the ball 64 from between the jaw 87 and the piston 89 the piston 77 can move downwardly although only slowly because of the small size of the conduit connecting the two pistons together. When the piston reaches an enlarged portion of the housing the oil can flow to the other side of the piston and the piston can complete its downward movement quickly, allowing the rod 77a to free the balls 85 which become disengaged from the groove in the housing wall and the hook member is then released. Since the spring 78 is positioned between the hook member and the piston the hook member is ejected by the spring.