Patent GB-341519-A (GB)
Title: Improvements in and relating to deflection or deviation indicators for use in or in connection with the navigation of air or other craft
IPC: G01C19/44
Filed: 1929-10-17
Abstract: 341,519. Navigational instruments. BROWN, J. P., 19, Park View, New Malden, Surrey. Oct. 17, 1929, Nos. 31542/29 and 6544/30. [Class 97 (iii).] A gyroscopic instrument for indicating the deviation of an aircraft &c. from a straight course comprises a rotatable spindle having a spherical bearing surface engaging a corresponding surface on a balanced rotor so as to drive the rotor frictionally while leaving the axis of the rotor free to oscillate with respect to that of the spindle, means being provided to cause slip to occur between the interengaging bearing surfaces. The rotor is enclosed in a casing and means are provided whereby movement of the rotor axis relatively to the casing can be determined from a point outside the casing. In Figs. 1 and 2 the spindle A is formed at its end as a sphere A<1> and the rotor C is mounted on a hub formed of two separable cup-like parts C<2>, C3 engaging the sphere A<1>. Vanes C<4> are provided on the rotor to reduce its speed of rotation relatively to that of the spindle. The spindle and rotor are enclosed in a substantially spherical casing formed of two parts D, D<1> having flanges D<5> bolted together with distance pieces D<6> interposed so as to leave openings through which air may leave the casing. Air admission openings D<4>, E are also provided in the casing. The part D<1> of the casing has an extension D<2> closed by a window H provided with a graticule &c. and the rotor has an axially-extending arm J the movements of the outer end of which relatively to the graticule indicate the deviations of the carrier from a straight path. In order quickly to restore the axis of the rotor into alignment with that of the spindle when the deviation ceases, a rod K is provided passing axially through the spindle A and sphere A<1>, and adapted to be pressed into engagement with the bearing surface C<3> of the rotor. The means shown for displacing the rod K consists of a member G<3> bearing thereon and connected to a diaphragm G<2> containing oil &c. to which pressure can be applied to displace the diaphragm. The rod K is restored by a spring K<2>. A small clearance is left between the interengaging curved surfaces of the spindle and rotor and lubricant is introduced into this space through the axial hole in the spindle. The whole apparatus may be mounted on trunnions so that its angular position can be adjusted, or it may be mounted in gimbals and weighted so that its position is constant with regard to the vertical. In a modification, Fig. 3, the arm J is connected to a stirrup L mounted on pivots L<1>, L<2>, the axis of which passes through the centre of the sphere A<1> so that movements of the carrier about an axis at right-angles to the plane of the Figure produce an increased movement about the axis L<1>, L<2> by the precession of the rotor. The deviation is indicated by a pointer L<4> on the pivot L2, the movement of the pointer being restrained by a spring. The stirrup is extended beyond the pivots L<1>, L2, and balanced by masses L<9>. In an alternative form the restraint on the movement of the pointer L<4> may be obtained by arranging the pivots L<1>, L<2> so that the line joining them does not pass through the centre of the sphere A<1>.