Patent GB-133330-A (GB)
IPC: B64C17/00
Abstract: 133,330. Macy, A. J. July 23, 1917. Balancing.-In an automatic stabilizer for aeroplanes, described with reference to the lateral control, a number of pendulums mounted upon an instrument board are adapted to close various contacts in a number of successive steps, according to the amount of deviation of the machine from its normal position, thereby operating a magnetic clutch which sets the aeroplane controls in motion, the controls being operated in a different manner for each successive step. The lateral controls or ailerons are operated by cables 4, 5, Fig. 3, attached to a lever 6 adapted to be operated by the shoulders of the pilot, the lever 288 being returned to normal position by springs 8. At one side of the lever 6 is mounted a casing 10 through which extends a rack-bar 11 interposed in the cable 4, the rack-bar being actuated by a motor 36, to operate the controls, when a magnetic clutch is actuated through the agency of the pendulums; on the other side of the lever 6, a switch 12, Figs. 3 and 21, is mounted, the switch bar 13 being interposed in the cable 5. Pendulum mechanism. Mounted transversely in the body 3 of the machine is a pendulum board 14, Figs. 3 and 4, having pivotally mounted thereon a central pendulum 15 provided with resilient contact members 16<a>. 16<b> adapted to contact with terminals 17<a>, 17<b> provided on the board; the board is also provided with two similar pendulums 20a, 20b for the electrical circuits which control the operation of the right and left hand controls respectively. Each of the pendulums 20<a>, 20b is provided on its inner side with a resilient contact 21a, 21<b> which normally engages a contact 22a, 22<b> on the board. Contacts 23<a>, 23b, 24<a>, 24b are also provided on the board, the contacts 24a, 24b being normally held away from the contacts 23a, 23<b> by L-shaped extensions 25a, 25<b> on the pendulums 20<a>, 20<b>. The pendulum 20a is mounted on a pivot 18<a>, Fig. 19, insulated from the board, the pivot being surrounded by an insulating-sleeve 19<a> on which is frictionally mounted a contact lever 26<a>. An insulating-sleeve 29<a> surrounds the hub of the lever 26<a> and carries frictionally mounted thereon a contact lever 30<a>. L-shaped extensions 27a, 31a are provided on the pendulum 20<a> to permit movement of the levers 26a. 30<a> towards, but to limit the movement away from, the pendulum. The pendulum 20<b> is similarly mounted and is provided with similar parts 26<b>, 30<b>, 27<b>, 31b. Servo-motor. The motor 36, Fig. 10, is provided with a vertical shaft 37 carrying a worm 49 meshing with worm-wheels 45<a>, 45<b> each carrying a number of magnetic coils; the coils, when energized, attract magnetic disks 44<a>, 44<b> attached to gear-wheels 43a, 43<b>, and thus, through gear-wheels 41, 40, actuate the rack 11. Switch and relay mechanism. On the switch 12, Fig. 21, are two sets of contacts, one set comprising the contacts 50a, 51<a>, 52a, and the other the contacts 50<b>, 51<b>. 52b, between which moves the insulated switch bar 13 provided with brushes 53<a>, 53<b>. Mounted on the front surface of the casing 10 are relay coils 55<a> 55b, Fig. 21, provided with pivoted armature bars 56a, 56b, which are normally in contact with terminals 58<a>, 58b, but which, when the coils are energized, engage contacts 57a, 57<b>. A magnetic brake 59 is provided for the large gear-wheel 41 to hold the same from rotation and thus to hold the controls temporarily in adjusted position. Operation. The operation of the device, which acts in three different ways according to the degree of the deflexion of the machine, is as follows : (1) When the machine tilts slightly, assuming the right wing is depressed, the pendulum board 14 is tilted slightly in a clockwise direction, and the contact 17<a>, Figs. 4 and 21, is brought into engagement with the pendulum 15. A circuit is thus established from a battery 61, Fig. 21, through wire 62, pendulum 15, contact 17<a>, wire 34<a>, pendulum 20<a>, contact 22<a>, and wire 32<a> to the relay 55<a>, returning by ground to the battery. When the relav 55<a> is energized, a secondary circuit is set up from the battery 61 through branch wire 64, armature 56<a>, contact 57<a>, wire 66a, contact 50<a>, brush 53a, contact 52a, and wire 68<a> to the clutch 46a, which causes the rack 11 to be operated and hence the controls of the machine. (2) If the machine tilts to a greater degree, the further movement of the board 14 causes the contact 22a to recede from the pendulum 20a, and the circuit to the relay 55a is broken; the circuit is, however, immediately re-established through the contact lever 26a which has been carried by the board into engagement with the pendulum 20<a>. The controls are thus operated until the brush 53a moves off the contact 50a, when an intermittent making and breaking of the circuit occurs, which holds the controls substantially at an adjusted position. When the machine begins a return tilting movement, the contact lever 26a immediately disengages the pendulum 20a, thus breaking the circuit to the relay 55a and completes the circuit to the brake coil 59 through the battery 61, armature 56a, contact 58<a>, wire 57<a>, contacts 23<a>, 24a, and wires 58, 69. The mechanism and controls are therefore held until the machine nears normal position, when the contact 23a recedes from the contact 24<a> and the springs 8 restore the controls to normal position. (3) If the machine makes a still greater tilting movement, the contact lever 30a is brought into contact with the pendulum 20a, and a circuit to the clutch 46<a> is established independently of the relay 55a, through wire 33a, contact 51<a>, brush 53<a>, and contact 52<a>; the controls are thus operated to a further degree, the limit being reached when the brush 53a moves off the contact 51a. On the return movement, the contact levers 26a, 30<a> immediately disengage the pendulum 20<a>, and the brake 59 is operated as described above. Specifications 133,331 and 133,333 are referred to.