GB874324A - Safety harness device - Google Patents

Abstract

874,324. Safety harness. PACIFIC SCIENTIFIC CO. March 5, 1958 [March 6, 1957], No. 7152/58. Class 141 An inertia operated safety harness device, to lock persons in vehicle seats during crashes and rapid deceleration, includes a tension member or webbing 14 attached to personal harness and passing through either slot 15 or 16 in a housing 11, Fig. 5, to be wound on a reel 21 rotated by coil spring 25, Fig. 3, anchored to the shaft 18 and to a cup sleeve 19 in housing 11, the tension member being secured to the reel as in Figs. 5a and 5b not shown. If the webbing 14 is withdrawn below a predetermined acceleration then an inertia flywheel 31 rotates with the shaft 18 but should the webbing 14 exceed this predetermined acceleration then the reel tends to rotate relative to the flywheel causing a thrust plate 37, biased towards the flywheel 31 by a spring 39 and rotatable with the shaft 18, to ride up on balls 41, Fig. 10, between it and flywheel 31 to bear against a dimple 54 on a sear 49 which is rotated on its pivot 48 against spring 53 to disengage a sear finger 55 from a dog finger 74 Figs. 7, 11, to permit a dog 72 to be rotated by a spring 73 to engage the teeth of a ratchet wheel 30 fixed to shaft 18 to prevent further paying out of the web 14. The spring 53 controls the acceleration at which the reel is locked and may be adjusted by a screw 38 in the shaft 18, the screw being held in position by a pin. To unlock the shaft, a lever 64 is rotated causing lever 67 to ride over finger 75 of dog 72, Figs. 7, 11; reverse rotation of lever 64 then causes lever 67 to retract dog 72 to its release position, the sear finger 55 falling behind the finger 74 to hold the dog in the release position. A central portion of a lever 76, Fig. 10, normally resting on the end of finger 74 under the pressure of spring 73, prevents chattering of the dog 72 when it rides over the teeth of the ratchet wheel on winding in of the webbing; whilst when the device is locked, to prevent accidental unlocking, the lever 76 being mounted on shaft 71 of dog 72, drops down behind finger 74 to prevent it moving out from under sear finger 55, the lever 76 being rotated out of engagement with the dog by a pin 69 on shaft 63 rotated by the lever 64. To prevent possible automatic locking and overrun of flywheel 31 over the shaft 18 on winding it at excessive acceleration, a lever 44, Fig. 7, is pivoted to the torque plate 33 rotatable with the shaft 18, a pin 45, on lever 44, engaging a slotted arm 43 of a member 42 which frictionally engages a wall 17 of the casing 11; this lever 44 being released from engagement with edge 47 of the flywheel 31 on unwinding to permit free rotation of the flywheel, but on winding in, it engages the flywheel causing it to rotate with the shaft 18 to prevent overrun. An auxiliary lever 62, Fig. 9, operable by a pilot rotates a pivot 61 to engage a projection 58 on sear 49 to move the sear and allow the dog finger 74 to pass beneath the sear finger 55 enabling dog 72 to lock the ratchet-wheel 30, the manual control 63, 64 then being unoperative until the lever 62 is returned to its normal position. This device is lockable for a predetermined rectilinear acceleration of the web 14 and compensates for decreases in the radius of the webbing and the reel by changing the angular acceleration at which the device will lock. The screw 38 is provided with left hand threads and as the shaft 18 rotates in the unwind direction, that is clockwise in Fig. 9, the screw threads itself into the shaft 18 to compress spring 39 and increase the force on plate 37 and the coupling force on the flywheel. The pilot may lock the device through lever 64, a control shaft pin 66 engaging the finger 56 of a sear 49 to raise it and the finger 55 until the dog 72 can slip under the finger and engage the ratchet wheel. Reverse rotation of the lever 64 unlocks the device as before. Reference has been directed by the Comptroller to Specification 761,518.