SU32747A1 - Gravitational variometer - Google Patents

Description

A gravitational variometer is proposed to speed up the duration of the observation and simplify the design of the instrument. Horizontal derivatives of horizontal components of gravity given in conventional variometers are rarely used in reconnaissance. According to the basic formula of Ethves, the action of these functions is proportional to the horizontal projection of the distance between weights. If this projection is made extremely small compared to the vertical distance between weights, then only the vertical derivatives of the horizontal components of gravity, most needed in exploration, will act on the vertical arm. In order to achieve the stated goal in the proposed variometer, in order to speed up the work with it, a vertical arm with such a small horizontal distance between the weights was used that not four but more Etherev functions were captured. Since in the variometer only two Etvesweh functions will act on the shoulder, it is enough to make observations at only three azimuths, for example, after 120, to determine the vector gradient, and two or one azimuths to determine its component.

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In the variometer system with observation :: or photo-recording, during the swings, the equilibrium position of the vertical arm and the logarithmic decrement of the attenuation depending on the air resistance and density of the rocker arm material and weights, but little dependent on its horizontal, are determined by the three extreme deviations. projection. 3 of the proposed variometer with a small period of oscillation of the shoulder around the elastic thread, successively the amplitudes differ so little from each other that the equilibrium position can be defined as the average between two successive short positions and; introduce only a damping correction, which will reach several percent of the oscillation amplitude. The initial amplitude of oscillations depends on: 1) the displacement due to gravity, the equilibrium position from the initial position when shoulder is de-positioned. This value, giving a correction for attenuation of several percent of the measured value, will be harmless; 2) the speed of rotation of the shoulder, which is obtained as a result of the impulse when the shoulder is disarmed. The increase in amplitude, due to this jolt, is so significant with conventional arresters that the percentage correction for attenuation is;

“Will be unacceptably large compared with the measured value. In order to avoid this drawback, a special device for jolting without impulses is used in the proposed variometer.

If these principles are observed, the proposed variometer is designed so that it can make all observations at one point in about a quarter of an hour. Since the zero point does not have time to shift during this time, the calculated position of the zero point on one point of a hundred must coincide with the position on the previous and after the other point, which can serve as a control.

The variational variometer shows TiepcneKTHBHO with a partial section in the schematic drawing.

The design of the variometer is as follows. A vertical tube 7, containing a vertical shoulder 2, rotates on an ordinary geodesic tribrach 5 separately or together with limb 4, connect a jen with diopter 5 and is fixed vertically by level 6. The vertical shoulder 2 with a load of m / and 5 arranged little eccentrically with respect to the shoulder 2 and enclosed by the reduction of air resistance in the drums 9 and 10 is, together with them, a body of rotation with respect to suspension air 77, so that there can only be air resistance when the system oscillates. The thread is clamped by conventional devices. At the top of the elevation and rotation of the thread there is a screw 13 passing through the screw 2 and having another schag. Both screws are provided with kenas with lock nuts. In addition to the type of arresting device, the following device has been used to dearm the vertical arm 2 without jerks, having the task of calming the oscillation of the arm 2 and quietly releasing the latter. On the spring 14 rotating on the springs 75 and 75, two contacts 17 and 18 are fastened. In the state that is not free after the release of the ordinary arresting device, the vertical arm 2 slightly touches and, so to speak, lies on the contacts; thread 77 is easy while they rejected from the plumb line.

Since the release of the customary-eeHHoro arresting device causes jolts.

shoulder 2 on pins 77, 75 will jump. For the first comfort, stop 19 with screw 20 presses shoulder 2 to contacts 77, 18. After that screw 20 and contact 7Р are pressed, then screw 2 / with screw is slowly pressed by cross lever 14 from the rocker arm 14; This yoke gradually assumes a vertical position. Contacts 77, 18 abut against a well-polished surface, so that friction does not create jolts. The distance between contacts 77 and 18 is shorter than the horizontal distance between weights 7 and so that when the contact opens, the moment of inertia of the rocker arms Olsha resistance than the contact force of the clutch.

The observation of the rocker is made by an autocallimetric tube 25 with an ocular 2 and a scale of 25. The index zero is visible in the mirror 26 of the rocker; the scale is visible in a fixed mirror 27. The amplitude of oscillations of the rocker arm is certainly so great that the zero index will go beyond the field of vision. Then counting is done by parallel indices + 1-j-2 -or - 1 - 2.

When converting the device from one azimuth to another, the air inside the tube 7 will be swirling. To stop it, radial flaps 25, 28 were made. For more precise work, the arresting screws and screws for tightening the thread are supplied with glands, and air is pumped out of the instrument.

For a device with such a short horizontal distance between weights, the vertical arm should hang on a thinner thread than usual. The thread must be electrically conductive, since otherwise the beam may be charged and interact with the sheath or other parts. In such an instrument quartz or glass silver-plated filaments can be used. Contacts 77 and 18 can be installed not at the same height both at the middle of the shoulder, but one against the upper weight 7 and the other against the lower 8. The contacts can be pressed in this case either by being connected together, or individually with their micrometer screw.