Monitor system

Abstract

The invention relates to a monitor system (10) with (h) a first monitor (12.1), (i) a second monitor (12.2), (j) a third monitor (12.3), (k) at least a fourth monitor (12.4) and (l) a base (16). According to the invention, it is intended that (m) the monitors (12.i) are fixed to the base (16) such that they can each be moved by way of a motor in at least two degrees of freedom, and that (n) the monitors are fixed to the base (16) by means of lazy tong drives.

Claims

1. A monitor system, comprising: a first monitor, a second monitor, a third monitor, at least a fourth monitor, and a base, a motor, wherein said first monitor, said second monitor, said third monitor, and said at least a fourth monitor are fixed to the base and are moveable by the motor in at least two degrees of freedom, and said first monitor, said second monitor, said third monitor, and said at least a fourth monitor are fixed to the base by lazy tong drives.

2. The monitor system according to claim 1, wherein each lazy tong drive has a tong arm which is fixed to the base at a proximal end, and comprises a distal end to which one of said first monitor, said second monitor, said third monitor, and said at least a fourth monitor is fixed.

3. The monitor system of claim 2 wherein one of said first monitor, said second monitor, said third monitor, and said at least a fourth monitor is fixed to the base in a way that the one of said first monitor, said second monitor, said third monitor, and said at least a fourth monitor can pivot about a monitor pivot axis.

4. The monitor system according to claim 1 wherein at least one monitor of said first monitor, said second monitor, said third monitor, and said at least a fourth monitor is fixed to the base such that it can be rotated by the lazy tong drives about a horizontal pivot drive pivot axis.

5. The monitor system according to claim 1 wherein said at least a fourth monitor includes fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth monitors, wherein a first monitor group which includes at least three of the first, second, third, and fourth monitors that are fixed to the base such that they can be collectively rotated, wherein a second monitor group which includes at least three of the fifth, sixth, seventh, and eighth monitors that are fixed to the base such that they can be collectively rotated, and wherein a third monitor group which includes with at least three of the ninth, tenth, eleventh, and twelfth monitors that are fixed to the base such that they can be collectively rotated, wherein the monitor system further comprises a first segment that is fixed to the base such that it can be automatically rotated about a vertical axis, and to which each of the first, second, third, and fourth monitors in the first monitor group are fixed, a second segment that is fixed to the base such that it can be automatically rotated about the vertical axis, to which each of the fifth, sixth, seventh, and eighth monitors in the second monitor group are fixed, and wherein the second segment is arranged above the first segment, and a third segment, that is fixed to the base such that it can be rotated about the vertical axis, to which each of the ninth, tenth, eleventh, and twelfth monitors in the third monitor group are fixed, and wherein the third segment is arranged above the second segment.

6. The monitor system according to claim 5 further comprising an electric control unit designed to: (i) move one or more of first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth monitors from a first configuration into a second configuration and/or (ii) rotate at least one of the first segment, second segment and third segment about the vertical axis.

7. The monitor system according to claim 5 wherein when in a first configuration, in at least one monitor group selected from the first monitor group, the second monitor group, and the third monitor group at least two of the first second third fourth fifth sixth seventh eighth, ninth, tenth, eleventh and twelfth monitors are arranged side-by-side, wherein said at least two monitors point in a first direction, at least two other monitors selected from said first second third fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth monitors are arranged side-by-side, wherein said at least two other monitors point in a second direction that is opposite to the first direction.

8. The monitor system according to claim 5 wherein the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth monitors are rigidly fixed to the base in terms of a rotational movement about a horizontal roll axis.

9. The monitor system according to claim 5 wherein the lazy tong drives include first, second, third, and fourth lazy tong drives for each of the first monitor group, second monitor group, and third monitor group, and when in a first configuration, in at least one monitor group selected from the first monitor group, the second monitor group, and the third monitor group the first lazy tong drive fixes the first monitor and the third lazy tong drive fixes the third monitor in said a least one monitor group, and the first and third lazy tong drives extend in opposite directions, and the second lazy tong drive fixes the second monitor and the fourth lazy tong drive fixes the fourth monitor in said at least one monitor group, and the second and fourth lazy tong drives extend in opposite directions, and wherein the first, second, third, and fourth lazy tong drives are moveable between a retracted position and an extended position, and are in the retracted position when in the first configuration.

10. The monitor system according to claim 9 wherein when in the retracted position, the first, second, third, and fourth lazy tong drives have an overall length, wherein the monitor system further comprises at least one yaw motor for yawing at least one monitor selected from said first, second, thirds fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh and twelfth monitors about a monitor pivot axis, and the overall length and an angle range of the at least one yaw motor are configured such that any contact between two adjacent monitors in a monitor group of the first, second and third monitor groups, regardless of a yaw position relative to the monitor pivot axis, is ruled out.

11. The monitor system according to claim 1 wherein each of the first, second, third, and a fourth monitors are in the first monitor group and are assembled such that they are rotatable about a common segment rotational axis and wherein said lazy tong drives include first, second, third, and fourth lazy tong drives, wherein each of the first, second, third, and fourth monitors are movable respectively by said first, second, third, and fourth lazy tong drive, wherein each of the first, second, third, and fourth lazy tong drives have a common first drive unit.

12. The monitor system according to claim 11, wherein the first drive unit has a first drive which adjusts a first axial distance of a first platform from a second platform, and each of the first, second, third, and fourth lazy tong drives are connected to the first platform at a first foot point of a respective first, second, third, and fourth tong arm, and to the second platform at a second foot point of their respective first, second, third, and fourth tong arm such that the respective first, second, third, and fourth tong arms can be retracted and extended by means of the first drive.

13. The monitor system of claim 12 wherein the first drive is a crank drive.

14. The monitor system according to claim 11 wherein each of the first, second, third, and fourth tong arms are connected to a first platform at their respective foot point by a pivot lever, wherein the first drive unit comprises a second drive which pivots a pivot angle of the pivot lever to adjust the first, second, third, and fourth lazy tong drives so that the first, second, third and fourth lazy tong drives may be collectively pivoted about a pitch angle.

15. The monitor system of claim 14 wherein either or both the first drive and the second drive is a crank drive.

16. The monitor system according to claim 14, further comprising a third platform, wherein each said pivot lever is hinged to the third platform, wherein the second drive is configured to adjust a second axial distance between the third platform and the first platform, and wherein the pivot angle can be adjusted by changing the second axial distance.

17. The monitor system according to claim 11 wherein the first lazy tong drive is a first crank drive which has (i) a first electric motor which is fixed to a first platform, (ii) a first bevel gear with a first crown gear, a first first-crank-drive bevel wheel, and a second first-crank-drive bevel wheel, (iii) a first first-crank-drive crank is rigidly connected to the first first-crank-drive bevel wheel, and (iv) a second first-crank-drive crank, which is rigidly connected to the first first-crank-drive bevel wheel, has (v) a first first-crank-drive connecting rod that is connected at a first end to the first first-crank-drive crank and at a second end to a second platform, and (vi) a second first-crank-drive connecting rod that is connected at a first end to the second first-crank-drive crank and at a second end to the second platform, and wherein the first electric motor is connected to the first crown gear for driving the monitor system such that the first-crank-drive crank can be rotated by the first electric motor, and wherein the first-crank-drive cranks are connected to the respective bevel wheels such that the first first-crank-drive crank is at its top dead center point when the second first-crank-drive crank is at its top dead center point, and that the first first-crank-drive crank is at its bottom dead center point when the second first-crank-drive crank is at its bottom dead center point.

18. The monitor system according to claim 17, wherein the first drive unit has a second crank drive, and the second crank drive has (i) a second electric motor, (ii) a second bevel gear with a second crown gear, a first second-crank-drive bevel wheel and a second second-crank-drive bevel wheel, (iii) a first second-crank-drive crank is rigidly connected to the first second-crank-drive bevel wheel, and (iv) a second second-crank-drive crank, which is rigidly connected to the second second-crank-drive bevel wheel, has (v) a first second-crank-drive connecting rod connected at a first end to the first second-crank-drive crank and at a second end to a third platform, and (vi) a second second-crank-drive connecting rod connected at a first end to the second second-crank-drive crank and at a second end to the third platform, and wherein the second electric motor is connected to the first crown gear for driving the monitor system such that the second-crank-drive cranks can be rotated by the second electric motor, and wherein the second-crank-drive cranks are connected to the respective bevel wheels such that the first second-crank-drive crank is at its top dead center point when the second second-crank-drive crank is at its top dead center point, and that the first second-crank-drive crank is at its bottom dead center point when the second second-crank-drive crank is at its bottom dead center point.

19. A building having a ceiling or mast or foot, wherein the building has a monitor system according to claim 1 which hangs on a ceiling or to a mast or is fixed to a foot that is located on the base.

Description

(1) In the following, the invention will be explained in more detail by way of the attached drawings. They show

(2) FIG. 1 a schematic diagram according to the invention of a monitor system from a lateral perspective,

(3) FIG. 2 a schematic view of the monitor system according to FIG. 1,

(4) FIG. 3 a schematic view from above of a monitor in the monitor system according to FIG. 1,

(5) FIG. 4 a schematic view of the monitor system,

(6) FIG. 5a a schematic view of a yaw motor of the monitor system,

(7) FIG. 5b a schematic view of the lazy tong drive of the monitor system according to FIG. 1, which

(8) FIGS. 6a, 6b, 6c and 6d depict the monitor system in a range of configurations,

(9) FIG. 7 shows a cross-section through a segment unit of the monitor system according to the invention that contains a group of monitors,

(10) FIG. 8 a perspective partial view of the segment unit according to FIG. 7,

(11) FIG. 9 a sectional view of the segment unit according to FIGS. 7 and 8,

(12) FIG. 10 a lateral view of the first crank drive of the segment unit,

(13) FIG. 11 the second crank drive of the segment unit and

(14) FIG. 12 the view of the segment unit according to FIG. 8 with fewer components than in FIG. 8.

(15) FIG. 1 shows a monitor system 10 according to the invention, which comprises a number of monitors 12.i (i=1, 2, . . . , N). The number N of the monitors may be 16, for instance. For the sake of clarity, the monitors 12.2, 12.6 and 12.10 are not depicted in FIG. 1. Any reference without a numerical suffix refers to all relevant objects. The monitors 12.i are fixed to a base 16 such that they can each be moved by way of a motor in at least two degrees of freedom, in the present case by three degrees of freedom. For instance, the monitor 12.1 can be rotated about a pitch angle .sub.1 and an angle of rotation as well as moved in a longitudinal direction r.

(16) The monitors, especially the monitor 12.1, are each fixed to a base 16 with a lazy tong drive 14.1. In the present case, certain sections of the base 16 are cylindrical.

(17) In the embodiment depicted in FIG. 1, the lazy tong drives 14 are fixed to the base 16 by means of a segment 18.1, 18.2 or 18.3, respectively. The segments 18.j (j=1, 2, 3) can be rotated about the base 16 independently of one another by means of a motor (not depicted). This means that the segment 18.1 can be rotated about an angle of rotation .sub.1 about a vertical axis D.sub.18 about the base 16, wherein this angle of rotation .sub.1 may correspond to an angle of rotation .sub.2 of the second segment 18.2. However, this is not necessary.

(18) Each lazy tong drive 14.1 has an arm 19.1 that has a proximal end 20.1, at which it is fixed to the respective segment 18.j, as well as a distal end 22.i to which the respective monitor 12.i is fixed. The area of the proximal end 20.i may also be referred to as a foot section. The lazy tong drive of the monitor 12.3 is shown in its retracted position in which it has an overall length L.sub.0.

(19) Each segment 18.j forms a segment unit 23.j (j=1, 2, 3) with the lazy tong drive 14.i attached to it. Each segment unit 23.5 can be rotated about a segment unit rotational axis D.sub.23.j. In the present embodiment, all segment units 23.j can be rotated about a common rotational axis D.sub.18. However, it is also possible that the segment unit rotational axes D.sub.23.5 run parallel, but not coaxially.

(20) FIG. 3 shows a view from above of the monitor system 10. The partial image on the right demonstrates that the monitors 12.i, for example the monitor 12.1, can be pivoted about a yaw angle about a vertical monitor pivot axis A.sub.12.1 by means of a yaw motor (not depicted).

(21) FIG. 3 also shows that the monitors 12.1, 12.2, 12.3 and 12.4 form a first group G1 that is fixed to a first segment 18.1. In terms of surface area, the monitors 12.5, 12.6, 12.7 and 12.8, which are fixed to the second segment 18.2, form a second group G2, and the monitors 12.9, 12.10, 12.11 and 12.12, which are fixed to the third segment 18.3, form a third group G3. By rotating the respective segment 18.j, each of the groups G is collectively fixed to the base such that it can be rotated about the horizontal rotational axis D.sub.18. All the monitors in a group are preferably arranged at the same axial height H.

(22) FIG. 4 depicts a perspective view of the monitor system 10 according to the FIGS. 1 to 3.

(23) FIG. 5 shows a partial view of the attachment of the monitor 12.1 to the lazy tong drive 14.1. All monitors are fixed to their respective lazy tong drive in the same way. It shows that a yaw motor 24.1 is available for pivoting the monitor 12.1 about the monitor pivot axis A.sub.12.

(24) FIG. 5b depicts a schematic view of the lazy tong drive 14.1. FIG. 1 shows that each lazy tong drive 14i, for example the lazy tong drive 14.1, comprises a number of tong segments 28.1.1, 28.1.2, . . . that are connected to one another such that the can pivot relative to one another. An electric motor 30 moves a thrust rod 32 and a first platform 33.1, which in the present case is in the form of a disc, in an axial direction relative to a second platform 31.1, which is also formed by a disc in the present case. A tong segmentthe tong segment 28.1.1 in the present caseis fixed to the first platform 31.1. If the thrust rod 32 is moved forward, the monitor 12.1 moves towards the base 16 (see FIG. 1). A pivot motor 26 allows the pivot angle of the respective pivot drive to be adjusted.

(25) By adjusting a first axial distance z.sub.1,2 between the first platform 31.1 and the second platform 33.1, i.e. a translational movement of the platforms relative to one another, a projection length of the lazy tong drives that are connected to the platforms changes.

(26) All foot sections 15.1 to 15.4 of the lazy tong drives 14.1 to 14.4 of the segment 18.1 are fixed to the platform 33.1. This means that the length of all lazy tong drives 14.1 of the segment 18.1 can be adjusted synchronously, thereby achieving one plane with a single drive. This structure requires constructional safety. Due to the mechanical coupling, all lazy tong drives 14.i of the first segment 18.1 are always the same length. Even if the motor 30 fails, an imbalance will still not occur. The lazy tong drives of the segments 18.2 and 18.3 can also be retracted and extended by means of precisely one electric motor.

(27) A second electric motor 34 meshes with a sprocket 35, which is fixed to the base 16. If the second electric motor 34 is activated, the first segment 18.1 rotates.

(28) In order to pivot all lazy tong drives 14.1 to 14.4 of the first segment 18.1 about the same pitch angle , each foot section 15.1 of a lazy tong drive 14.1 is fixed to a respective slider 37.1. If a third electric motor 46 rotates a sleeve 42 with external teeth, a second disc 44.1 rotates relative to the first disc 33.1. The slider 37.1 engages at one end, such as a sliding block, with a recess in the second disc 44. The end of the slider 37.1 is moved radially outwards by the recess such that the monitor 12.1 (see FIG. 1) pivots downwards about a horizontal axis H.sub.14.1. Since all foot sections 15.1 (i=1, . . . , 4) of the lazy tong drives 14.i of the first segment 18.1 are fixed in the same way, all monitors 12.1 of the first segment 18.1 pivot downwards about the same pitch angle .

(29) The lazy tong drives 14.5 to 14.8 of the second segment 18.2 are not capable of conducting a pitching motion. The lazy tong drives 14.9 to 14.12 of the third segment 18.3 have a pitching drive that allows only for an upward movement. This may be configured, for instance, symmetrically to the drive described above for the lazy tong drives 14.1 to 14.4.

(30) FIG. 5b shows a schematic image of an electric control unit 39 that is connected to all motors of the segment 18.1 in order to drive it. The control unit 39 comprises a digital memory in which a movement programmeand, where possible, films or images that are to be presented on the monitors 12.iare stored. The control unit 39 is preferably connected to other control units, for example by way of a radio connection. It is also possible for a central electric control unit to be provided, which controls all motors of all segments and the monitors.

(31) FIG. 6a shows the monitors in a first configuration. It should be recognised that 6 monitors form a 23 matrix, wherein the monitors 12.1 and 12.2 are arranged side-by-side and point in a first direction R1. The monitors 12.3 and 12.4 point in a second direction R2 that is opposite to the first direction R1; they are also arranged side-by-side. As can be seen in the left-hand partial image in FIG. 3, the lazy tong drives 14.1 and 14.3 each extend in opposite directions. The same applies for the lazy tong drives 14.2 and 14.4.

(32) The monitor system 10 is arranged inside a building 36 and hangs on a mast 40. Alternatively, the monitor system 10as depicted in FIG. 4may hang on a ceiling 41 of the building.

(33) FIG. 6b shows a second configuration where three monitors are arranged above one another and together point in one direction. The resulting four directions are perpendicular to each other.

(34) FIG. 6c depicts another arrangement in which the lazy tong drives have been extended to the maximum and all monitors point in different directions.

(35) FIG. 6d shows a further configuration in which the monitors are each extended further the higher they are arranged.

(36) FIG. 7 shows the segment unit 23.1, which comprises the first group G1 of the monitors 12.1, 12.2, 12.3 and 12.4, wherein the monitor 12.3 is not depicted. All monitors 12.i can be rotated about the rotational axis D.sub.23.1.

(37) The lazy tong drives 14.i (i=1, 2, 3, 4) have a common first drive unit 48, explained in more detail below. Since the lazy tong drives 14.i are structurally identical, a description of the lazy tong drives that are not depicted is not be provided.

(38) Each lazy tong drive 14.i comprises a first foot point 50.i that is configured at the proximal end of the respective tong arm 19.i. The respective tong arm 19.i is fixed to the first platform 33.1 by means of the first foot point 50.i. With a second foot point 52.i, the first platform 33.1 moves in the axial direction, i.e. along the rotational axes D.sub.23.1, causing the respective foot points 50.i, 52.i move away from one another and the corresponding tong arm 19.1 is inserted.

(39) FIG. 10 shows details of the drive unit 48.1, which comprises a first drive in the form of a first crank drive 54. The first crank drive 54 has a first electric motor 56 that is fixed to the first platform 33.1 (see FIG. 7). The first crank drive 54 also comprises a first bevel gear 58 with a first crown gear 60, a first first-crank-drive bevel wheel 62.1 and a second first-crank-drive bevel wheel 62.2. A first first-crank-drive crank 64.1 is rigidly connected to the first first-crank-drive bevel wheel 62.1. A second first-crank-drive crank 64.2 is rigidly connected to the second first-crank-drive bevel wheel 62.2. A first end of a first-crank-drive connecting rod 66.1 or 66.2 is fixed to the respective first-crank-drive cranks 64.1, 64.2. The respective second end is connected to the second platform 31.1.

(40) The first crown gear 60 is driven by a first spur gear 68, which in turn meshes with a drive gearwheel 70 of the first electric motor 56. If the electric motor 56 is activated, the first crown gear 60 and therefore the first-crank-drive cranks 64.1, 64.2 rotate. This causes a first axial distance z.sub.1,2 between the first platform 31.1 and the second platform 33.1 to change.

(41) FIG. 9 shows that a change in the axial distance z.sub.1,2 causes the projection length of the tong arm 19.i to change.

(42) FIG. 7 shows that the first drive unit 48.1 comprises a second drive in the form of a second crank drive 72, by means of which the pivot angle of the pivot levers 74.i can be changed. The pivot levers 74.i are each connected at a first hinge point 76.i to the first platform 33.1 such that they can be pivoted. A second hinge point 78.i is connected to a third platform 80.1. If the electric motor 56 is activated, the axial position of the hinge point 76.i relative to the first platform 31.1 changes.

(43) FIG. 11 depicts the second drive 72 in detail. It should be recognised that the second crank drive 72 has a second electric motor 82 that is fixed to the first platform 33.1 (see FIG. 8). A second drive gearwheel 84 of the second electric motor 82 meshes with a second spur gear 86, which is rigidly connected to a second crown gear 88.

(44) The second crown gear 88 meshes with two second-crank-drive bevel wheels 90.1, 90.2, which in turn are connected to the respective second-crank-drive cranks 92.1, 92.2 such that they are torque-proof. The second-crank-drive cranks 92.1, 92.2 are connected to corresponding first ends of second-crank-drive connecting rods 94.1, 94.2, which are connected at their respective second end to the third platform 80.1. If the second spur gear 86 rotates, a second distance z.sub.1,3 between the first platform and the third platform 80.1 changes.

(45) FIG. 12 shows that an activation of the first electric motor 56 causes the spur gear 68 to rotate, which causes the first-crank-drive crank 64.1 and the second first-crank-drive crank, which lies opposite and is not depicted in FIG. 12, to rotate. The second platform 31.1 is configured such that it cannot be moved in the axial direction along the rotational axis D.sub.23.1. Hence, if the first electric motor 56 is activated, the first platform 33.1 moves downwards in the present case. This results in the extension of the lazy tong drives 14 (see FIG. 7). In contrast, the pitch angle (see FIG. 1) only changes a little. The first electric motor 56 and the second electric motor 82 are connected to the control unit 39 (see FIG. 9). The control unit is designed such that the extension of the monitors can be executed in a straight line. Furthermore, the control unit is designed such that a pitch motion of the monitors is possible without changing the projection length.

(46) If the second electric motor 82 is activated, the second-crank-drive crank 92.1 and the second second-crank-drive crank 92.2, not depicted in FIG. 12, rotate. This causes the third platform 80.1 to move relative to the first platform 33.1 and the pivot angle (see FIG. 7) to change. As a result, the pitch angle changes and, in the present case, so do the tong lengths. When appropriate movement ranges are selected, this coupling may be used to prevent collisions. The trajectories are calculated by way of kinematics, which enables a de-coupled monitor movement. The pivot drives are preferably designed such that a pitching from the horizontal direction of extension causes an increase in the projection length.

(47) The extreme positions that the platforms can take relative to one another are determined by the top and bottom dead centre points of the cranks 64.1, 64.2, 92.1, 92.2. This enables the determination of the interval of the pitch angles. As depicted in FIG. 1, it is favourable if the monitors in the lowest group, namely the first group G1, can only be pivoted downwards from the horizontal, and the monitors in the top group, namely the third group G3, can only be pivoted upwards. This rules out any collisions occurring between the monitors.

(48) Due to the fact that the crank drives effectively restrict the possible pitch angles , the monitor system is intrinsically safe. It should be noted that it is possible, but not necessary, for there to be three monitor groups. Specifically, there may also be only one monitor group, but two, three or four monitor groups are also possible.

(49) FIG. 8 shows that, by means of a guiding column 96 inside a guiding sleeve 98, the platforms will not twist against each other and only a purely translational movement is possible. Springs 99.1, 99.2 serve as energy stores for a movement of the first platform relative to the third platform and reduce the maximum torque to be generated by the corresponding drives.

(50) Optional additional springs, which are not depicted, serve as energy stores for a movement of the first platform relative to the second platform.

(51) TABLE-US-00001 Reference list: 10 monitor system 12 monitor 14 lazy tong drive 15 foot section 16 base 18 segment 19 tong arm 20 proximal end 22 distal end 23 segment unit 24 yaw motor 26 pivot drive 28 tong segment 30 electric motor 31 second platform 32 thrust rod 33 first platform, disc 34 second electric motor 35 sprocket 36 building 37 slider 39 electric control system 40 mast 41 ceiling 42 sleeve 44 second disc 46 third electric motor 48 drive unit 50 first foot point 52 second foot point 54 first drive, first crank drive 56 first electric motor 58 first bevel gear 60 first crown gear 62 first-crank-drive bevel wheel 64 first-crank-drive crank 66 first-crank-drive connecting rod 68 first spur gear 70 drive gearwheel 72 second drive, second crank drive 74 pivot lever 76 first hinge point 78 second hinge point 80 third platform 82 second electric motor 84 second drive gearwheel 86 second spur gear 88 second crown gear 90 second-crank-drive bevel wheel 92 second-crank-drive crank 94 second-crank-drive connecting rod 96 guiding column 98 guiding sleeve pitch angle yaw angle rotational angle pivot angle z.sub.1, 2 first axial distance z.sub.1, 3 second axial distance A.sub.12 monitor pivot axis D.sub.18 vertical axis, segment rotational axis G grouph horizontal H axial height H.sub.14.i horizontal axis i, j running index L.sub.0 overall length N number of monitors r longitudinal direction, radial direction R direction S centre of gravity