Patent GB-1011757-A (GB)
Title: Inertia-responsive device for controlling the rotation of a rotor
IPC: B60R22/405
Filed: 1962-09-25
Abstract: 1,011,757. Locking rotary elements. AIRCRAFT MECHANICS Inc. Sept. 25, 1962 [Sept. 29, 1961], No. 36344/62. Heading F2E. [Also in Division A3] An inertia-responsive device for controlling the paying-out of a safety harness belt 28, Fig. 1, wound on a rotor 20 comprises a ratchet wheel 41 concentric with the rotor and rotatable therewith, a spring-biased pawl 60 for engagement with the ratchet wheel to stop its rotation in one direction, and inertia responsive means 57, 57a, Fig. 4, operable when the rotor is at rest or moving with an angular acceleration below a predetermined value, or a linear retardation below a predetermined value, to oppose the biasing means and hold the pawl out of engagement with the ratchet wheel, and further operable both in response to an angular acceleration of the rotor above said predetermined value or a linear retardation above said predetermined value, to release the pawl for engagement with the ratchet. During normal operation of the device, that is when the drum 20 is rotated at a nominal speed in paying off the web belt 28, a first gear 56, Fig. 8, concentric and rotatable with the drum 20 rotates a second gear 50 and an inertia flywheel 51 which are mounted on a shaft 53 journalled in a freely pivoted lever 57. A pin 57a, Fig. 4, on the latter engages in a shallow detent 68 in the pawl 60 to oppose the force of the spring 65 biasing the pawl into engagement with the ratchet 41. However, if the inertia of the wheel 51 is great enough to momentarily resist a certain degree of rotational acceleration of the second gear 50, the latter will ride counter-clockwise around the periphery of the first gear 56 due to the pendulum mounting of the lever 57. The pin 57a is thus dislodged from its detent 68 and the pawl 60 is forced by the spring 65 into engagement with the ratchet 47 to prevent further rotation of the drum 20. Also if the right-hand side of the mechanism, Fig. 4, is directed forward of a vehicle a sudden forward deceleration would tend to swing the arms 57, 50, 51 counter-clockwise, unseating the pin 57a and allowing the pawl 60 to engage the ratchet wheel 41. The pawl 60 may be moved out of engagement with the ratchet 41 by a lever 73 which is rotated by a handle 80, to abut and then to cam the pawl 60 out of engagement with the ratchet and permit the pin 57a to seat in the detent 58. The rotation of the lever 73 also moves a manual locking dog 71 into engagement with the ratchet 41 to prevent rotation thereof. The handle 80, which is biased by a spring 82 attached thereto and abutting a fixed pin 84 so that the lever 73 assumes the position shown in Fig. 4, may be operated by a flexible connector on the remote end of which there may be provided a lock to maintain the dog 71 in engagement with the ratchet 41. A rapid take-up of the belt by the drum 20, accompanied by a sudden stoppage may cause the second gear 50 to continue its counter-clockwise rotation, Fig. 4, and crawl around the periphery of the first gear 56, thus unseating the pin 57a. This may be prevented by a spring clip wire 95, Fig. 9, which is clamped to the hub flange 51a of the flywheel 51 and projects into a double-ended cavity 91 provided in a block 90. As the flywheel turns in response to the paying off rotation of the drum the wire 95 is rotated so that its end is positioned longitudinally of the furthest cavity end 93. However, opposite rotation of the drum results in a raising of the end of the wire 95 so that its end abuts the short end 92. Thus a rapid rotational deceleration of the drum when winding up the belt cannot cause the second gear to crawl around the periphery of the first gear.