Abstract: The invention concerns a tilt-compensating indicator device for a compass (100) comprising a magnetic field detection device (20) which is mounted on a conical bearing (7) and is accommodated in a housing (100') of the compass (100). The indicator device (30) is rotatably mounted on the magnetic field detection device (20) by means of a receiving bearing (8,10) whose bearing shaft (8), accommodated in bearing elements (10) of the magnetic field detection device (20), extends substantially at right-angles to the north-south direction of the magnetic field detection device (20).

Abstract: A three-dimensional homologous surveying instrument includes a base with an outer spherical shell mounted thereon for receiving therein a ring-shaped shell holder, an intermediate spherical shell and an inner spherical shell with respective zero references at in a homologous relationship with each other. The inner spherical shell rotates within the intermediate spherical shell about X-axis. The intermediate spherical shell rotates within the ring-shaped shell holder about Y-axis. The outer spherical shell is positioned in the base to serve as the X-axis. The inner spherical shell and the intermediate spherical shell each have a pendulum at the bottom. The outer spherical shell, the ring-shaped shell holder, the inner spherical shell and the intermediate spherical shell form a gyroscopic device for three dimensional surveying through X-axis, Y-axis and Z-axis concomitantly. The pendulum of the inner spherical shell is mounted with a compass for indicating the direction of the angle of slope being surveyed.

Abstract: An improved magnetic compass unit consists of a compass bowl, a card assembly pivotally supported on a pivot shaft within the bowl, the card assembly consisting of a compass card and a magnet, and at least one active indicator pin adapted for alignment with the lubber line of a supporting vehicle and with an adjacent degree indicia line upon the compass card. The active indicator pin is mounted to pivot apart from the pivotally mounted compass assembly, whereby the indicator pin remains disposed generally in a common plane with the adjacent degree indicia line during conditions of compass roll. The card assembly may be with or without gimbal mounting.

Abstract: A compass which is self-compensating for dip of its pointer arms irrespective of variances in the earth's magnetic forces at different geographical locations includes a magnet disposed beneath respective proximal portions of the pointer arms so that the pointer arms are parallel to the magnetic field of the magnet, with the magnet constructed to be counterbalancing with regard to the earth's magnetic fields. In a preferred embodiment, the magnet comprises a plastic disk with magnetic particles embedded therein, the disk having a chordal portion removed therefrom immediately beneath one pointer arm, and a damper pan assembly is controlled by a lift arm to selectively dampen the movement of the pointer arms.

Abstract: A compass design particularly for wrist mounted and hand held compasses which includes a first exterior, fluid tight case having a pair of pivot members respectively on the upper and lower surfaces thereof for rotatably mounting a second interior case member which second case member is provided with a horizontally pivotal magnet body which magnet body is permitted to move a predetermined degree with respect to a normal horizontal position to accommodate for magnetic inclination and which outer case is filled with liquid to place the inner case in substantial equilibrium between the pivot members such that the inner magnet bearing case will be substantially frictionally free to rotate in the outer case.The mounting for the magnet body within the inner case allows the magnet body to oscillate and therefore provide free movement even though the magnet is not held in a horizontal position.