DE29613770U1 - Low energy polar mount rotating device with motor drive for guiding a satellite receiving antenna for the purpose of receiving various satellite positions - Google Patents

Description

Designation

Low Energy Polar Mount - Motor-driven rotating device for guiding a satellite receiving antenna for the purpose of receiving different satellite positions.

short version

Rotating device (polar mount) with motor drive and attachment option for any antenna for receiving satellite signals from several satellites with optimized torque transmission in both directions by attaching the antenna with the center of gravity near the axis of rotation.

The present invention brings about a reduction in the actuator motor power, which is achieved by a modification of the arrangement of the antenna to its support compared to the known arrangements.

Description:

In the polar mount devices known to date, the antenna is attached to a mast that is mounted above the rotating device with a rotating axis (Figure 1). The power consumption of the motor decreases the closer the rotating part approaches the east/west end points from the south. Due to the weight of the antenna, the rotating device is pushed towards the end points and the motor only has a braking function. In the opposite direction, i.e. towards the middle (south), the motor has to work hard because the antenna pushes in the opposite direction with its weight.

When using digital controls, satellite receivers or signal generators are used that control and supply energy to the motors and reception converters together via a coaxial cable (Figure 4). For cost reasons, the receivers or signal generators only have a certain power output. Additional power losses arise from the resistance of the coaxial cable. It is therefore important to keep the power consumption of the servo motor as low as possible and constant over the entire rotation range. This is made possible by the present invention.

Description of the mechanical mode of operation:

The invention has the following features: The antenna reflector is attached to the polar mount below the axis of rotation (drawings 2/3). In this way, the center of gravity of the rotating part approaches the axis of rotation A-B (drawing 2), whereby raising and lowering the entire arrangement with antenna is largely replaced by rotation around its own axis. A reduction in energy requirements from east to south or from west to south by over 50% is achieved with the new arrangement. Ideally, the motor only overcomes the small friction losses of the axis of rotation in both directions.

Mechanical mode of action with calculations based on a model:
The model (Figure 5) consists of the rotation axis AB of the polar mount, its mass (SP replaces the receiving antenna), which is mapped to a point, and a line BD, which represents the mounting tube. The center of gravity of the system is approximately on the mounting tube. A polar axis angle of a° is assumed.

Now a Cartesian coordinate system is projected onto the arrangement (Figure 6). The Y-axis coincides with the axis of rotation, the X-axis with the lever arm of the center of gravity (SP) with respect to the axis of rotation. Now the weight force is split into its vertical and horizontal components Fx, Fy (S-coordinate system) as a reference point and the work required to raise the system from ß to 0° is calculated.
Fx = -(mg) cos a , Fy = -(mg) sin a

The component Fy only has to be applied by the bracket and not by the actuator.

The work required to lift the antenna is calculated as follows (Figure 7):

r=Rsinß (lever arm) _r S=R(I -sin ß)

ß = Deviation from south direction ¹ (90°)

W= Fds = F { s) = -mg sin α -(1-sinß)R = R mg (1-sinß) sin a

(R=radius, m=mass constant, g=gravity constant, a= polar axis angle)

Application of the ray theorem (Figure 8)

a is the distance between the center of gravity SP and the intersection of the axis of rotation with the tube.
R ₁ a,

W,«,, = S Watt = -~ ^eu Watt
new &kgr;,.

alt a _a|t

Summary : The work of the servomotor depends on the mass of the antenna, which is constant and cannot be changed, and the length of the lever arm to which it is attached. The new arrangement reduces the mechanical demands on the servomotor in direct proportion to the shortening of the lever arm. The innovation creates a rotating arrangement that can reduce the energy requirements of the servomotor by up to 60% compared to the known arrangement. This reduction in power has been proven in practical tests.

List of reference symbols for the drawings §J1 Mnd*S2. ^: . · '·'···

1 support mast to which the polar mount is attached.

2 Setting polar axis angle

3 axis of rotation

4 Pipe to which the antenna is attached

5 Azimuth adjustment device of the satellite receiving or transmitting antenna

6 Polar axis angle 6a Declination angle

7 Satellite receiving or transmitting antenna

8 Elevation angle

9 reception converter (LNB)

10 Satellite direction

11 Sprocket

12 Engine

13 Remote control

14 Signal generator (receiver interface)

15 coaxial cables

16 Engine

Claims (2)

Expectations; 1. Rotating device (polar mount) with motor drive and fastening device for any antenna for receiving satellite signals from several satellites, characterized in that the antenna reflector is attached to the polar mount below the axis of rotation, near the axis of rotation A-B (drawings 2 and 3). In this way, the center of gravity of the rotating part approaches the axis of rotation A-B, whereby raising and lowering of the entire arrangement with antenna is largely replaced by rotation around its own axis. 2. Rotating device according to claim 1, characterized in that a motor is used that is controlled by a signal generator that can be included as standard in the playback device. For this purpose, the signal generator sends a digital data packet with, for example, 22 KHz pulse width modulation to control the motor and thus to position the antenna via the coaxial cable immediately after the program switch. Additional control cables to the motor are not required. The motor is supplied with energy using the 14/18 V operating voltage for the feed system via the coaxial cable, which also transmits the IF signals of the feed system and the signals to control the motor (drawing 4).