Device for controlling the position of a tunnelling machine

The device for controlling the position of a tunnelling machine has a housing (2) swivelling about an axis (3), within of which three measuring surfaces (11, 14, 18) are arranged. The first two measuring surfaces (11, 14) have openings of passage (12) for a laser beam (5), the clear width (a, c) of which diminishes in the direction of propagation of the laser beam (5). The clear width (a) of the first measuring surface (11) is smaller than the diameter (e) of the striking area of the laser beam in this measuring surface (11). The receiver elements (13, 16, 17) are arranged symmetrically in relation to the axis of the openings of passage or in case of the last measuring surface (18) in the axis and within the normal projection of the edges of the openings of passage of a preceding measuring surface (FIG. 3).

The invention relates to a device for controlling the position of a 
tunnelling machine in relation to a guide beam, within the measuring 
surfaces receiver elements for the guide beam being arranged, wherein at 
least the measuring surface located next to the emitter of the guide beam 
is transmissive for the passage of the guide beam in at least one opening 
of passage. Such a device is for instance to be taken from the AT-PS No. 
337 128. In this well known embodiment the receiver is mounted adjustably 
in horizontal and vertical position on a tunneling machine. The receiver 
device consists of two receiver surfaces arranged one behind the other in 
direction of propagation of a laser beam, wherein the first surface facing 
the emitter of the laser beam has a drill hole. On the second receiver 
surface behind the first a number of light-sensitive elements is arranged. 
The receiver device is first of all oriented so that the laser beam can 
pass through the drill hole of the first receiver surface, and the angular 
deviations and displacements of the tunnelling machine result from its 
admission to one or several of the light-sensitive elements of the second 
or posterior receiver surface. Analysis is effected by a calculator and 
requires several complicated mathematical evaluations. In addition to that 
at least in the second posterior receiver surface a great number of 
light-sensitive elements is required, the signals of which must be 
interpreted separately from each other in order to allow a corresponding 
distinction of the angular displacement. 
The invention aims at simplifying a device as described above and at making 
it possible to achieve a reliable statement on angular displacements of a 
tunnelling machine with a relatively low number of sensors and therefore a 
diminished number of signalling lines. The embodiment according to the 
invention aims furthermore at diminishing essentially the mathematical 
effort and at making analysis possible to be effected with simple logical 
circuits reliable in operation. 
In order to solve this problem the invention consists essentially in that 
the clear width of the opening of passage is smaller than the 
cross-sectional dimension of the striking spot of the guide beam, and that 
in a further measuring surface at least one receiver element is arranged 
within the normal projection of the opening of passage, preferably in the 
axis or plane of symmetry of the opening of passage or symmetrically to 
these. By the fact that the clear width of the opening of passage is 
smaller than the cross-sectional dimension of the striking spot of the 
guide beam in this opening of passage, a first relatively simple control 
for the correct position results from the fact that light-sensitive 
elements give a signal at the edge of the opening of passage at the same 
time. When starting out from such a position the receiver is swivelled and 
the corresponding swivelling angle of the receiver is measured, the actual 
position of the tunnelling machine can be determined by the fact that a 
further signal occurs in the second posterior measuring surface if the 
receiver element be arranged in this further measuring surface in the axis 
or plane of symmetry of the opening of passage. In the simplest case three 
receiver elements are sufficient, by which simultaneous measuring of a 
signal in all of the three receiver elements with regard to the swivelling 
angle of the receiver gives a statement concerning the correct position of 
the tunnelling machine. The simultaneous occurrence of signals in three 
receiver elements is convertible into a signal for the correct position 
with a relatively simple logical circuit without the need of strenuous 
mathematical operations. 
Preferably the device according to the invention has at least two receiver 
elements opposed to each other in relation to the axis or plane of 
symmetry in a distance which is smaller than the cross-sectional dimension 
of the striking spot of the guide beam. If deviations in the height 
direction be of secondary importance, two such receiver elements are 
sufficient in the measuring surface which has the opening of passage for 
the guide beam, in which angle of inclination and of gradient can be 
determined conventionally by a clinometer. For this purpose the receiver 
must be solely cross-sliding and swivelling about an axis which intersects 
the axis of the laser beam in order to obtain the signals required for 
correction. Swivelling of the device is granted preferably about an axis 
which is placed centrically within the opening of passage of the measuring 
surface located next to the emitter of the guide beam, so that the 
required adjusting for the receiver is reduced to a minimum. 
The senistivity and precision of the statement achievable with such a 
simple device can be increased essentially if--as corresponds to a 
preferred embodiment of the device according to the invention--at least 
three measuring surfaces be arranged one behind the other in direction of 
propagation of the guide beam, in which at least two contiguous measuring 
surfaces have openings of passage. Also for this a simple logical circuit 
is sufficient for analysis and the following cases can for instance be 
distinguished. The guide beam gives in the first measuring surface only 
one signal of a receiver element to one side of the opening of passage, 
whereas in the following measuring surfaces no signals occur. In this case 
the receiver must be swivelled or slid until a signal occurs likewise at 
least in the second measuring surface, wherein this signal occurs for 
instance on that side of the opening of passage of the second surface 
which is opposed to the receiver element giving a signal to the first one. 
From such a combination of signals the direction of a required correction 
of the orientation of the receiver can be definitely gathered and a 
lateral sliding of the receiver as well as a further swivelling results 
finally in that position in which at least two receiver elements on both 
sides of the opening of passage in the first measuring surface and the 
receiver element in the last measuring surface give a signal at the same 
time. In this case no signal occurs in the receiver elements of the second 
measuring surface if the clear width of the opening of passage in the 
second surface be approximately the same as the clear width of the opening 
of passage in the first measuring surface, wherein the axis or 
longitudinal median plane of openings of passage arranged one behind the 
other must be in line with each other and coincide with the position of 
the receiver elements arranged centrically in the last measuring surface. 
The embodiment can be also effected so that the clear width of successive 
openings of passage in direction of propagation of the guide beam 
diminishes in the indicated direction. In this case an embodiment is 
possible in which the correct position results from the receiver elements 
on both sides of the opening of passage giving a signal simultaneously in 
each measuring surface as well as the receiver element(s) in the last 
measuring surface. The coincidence of such signals can be again determined 
with simple logical circuits. Preferably the receiver elements arranged 
within the measuring surfaces having an opening of passage are arranged at 
the edge of the opening of passage. Most simply, the opening of passage is 
shaped as a slot oriented in essentially vertical position wherein 
preferably a number of receiver elements is arranged in pairs parallel to 
the plane of symmetry of the slot. When the signals in longitudinal 
direction of the slot of superposed receiver elements are analyzed 
separately, an information concerning the height position of the machine 
results, wherein in at least three measuring surfaces also a statement 
about the angular position can be made. Such an angular statement for 
angles of inclination and gradient results when the signals in successive 
measuring surfaces occur in different height position, wherein again 
separate evaluation of the single receiver elements in the single surfaces 
is presupposed. Also several of such receiver elements which are 
superposed in height direction can be combined to groups, whereby a 
correct statement concerning the lateral deviations of the machine, 
particularly concerning inclination relatively to the required linear 
longitudinal axis is by no means impaired. In this case it is sufficient 
that the receiver elements on one side of the plane of symmetry of the 
slot are formed by the ends of light wave conductors, to the other ends of 
which a signal receiver common to several receiver elements is connected, 
whereby the expenditure of signal receivers and signal lines as well as of 
the logical circuit is essentially diminished. 
A particularly high reliability in operation results from the arrangement 
of the single receiver elements being effected so that two neighbouring 
pairs of receiver elements which are opposed in relation to the slot, are 
arranged in a distance from each other so that a diagonal of the 
quadrangle formed by these receiver elements is smaller than the 
cross-sectional dimension of the spot of striking of the beam. In this 
case a position of the receiver which gives a single--valued statement in 
relation to the angular position relative to the linear longitudinal axis 
can be looked for in every position of inclination of the machine. 
The device according to the invention represents thus a simple electronic 
view-finder, with which self-acting corrections of the deviation of the 
machine can be made possible particularly simply. The view-finder can be 
mounted in a box-molded housing elongated in height direction and can be 
shaped essentially smaller than corresponding mechanical view-finders.

In FIG. 1 the housing of the device is marked with 1 and 2. Housing 2 is 
swivel-mounted, the pivot being marked with 4. The guide beam is indicated 
with 5 and strikes the elongated front surface 6, which is transmissive 
for the guide beam. The drive of the frame 2 at right angles to the axis 
of the machine can be effected by means of a (nonrepresented) hydraulic 
cylinder and a chain drive or by means of a hydro- or electro-motor and by 
a screwed spindle and nut. Pivot drive for swivelling about the axis 3 can 
be lead off a hydraulic cylinder 7, as is represented in FIG. 2, wherein a 
pinion 8 meshes with a segment of a pinion 9, by which the corresponding 
position of swivelling is picked off and can be sensed by an electrical 
position indicator 10. Conversely, the electrical position indicator 10 
can be developed as a motor for the pivot drive, wherein the position of 
swivelling can be deduced from the position of the piston in the hydraulic 
cylinder 7. The function of the device is explained best with the aid of 
FIG. 3 and FIG. 4. 
In FIG. 3 a guide beam 5 formed by a laser beam is indicated which passes a 
light-transmissive front wall 6 and strikes a first measuring surface 11. 
The first measuring surface 11 has an opening of passage formed by a slot 
12 for the laser beam, at the edges of which light-sensitive elements 13 
are arranged on both sides of the slot. Slot 12 forms a diaphragm for the 
guide beam formed by a laser beam and has a clear width a. In distance f 
behind the first measuring surface 11 a second measuring surface 14 is 
arranged, which has again an opening of passage formed by a slot 15 and on 
both sides of the opening of passage light-sensitive elements 16. The 
clear width b of the slot 15 is in this smaller than the clear width a of 
the slot 12 and the distance c of the light-sensitive element 16 is 
smaller than the clear width a of the slot 12 in the first measuring 
surface. If the housing 2 be correctly positioned the beam passing through 
the slots 12 and 15 strikes the light-sensitive element 17 of the third 
measuring surface 18. The housing 2 is swivelling about the axis 3 and 
this axis 3 is in the plane of the first measuring surface 11. The 
light-sensitive elements 13 of the first measuring surface 11 are in this 
arranged in a distance d on both sides of the slot 12, which is smaller 
than the diameter e of the spot of striking of the beam 5. In case of 
inclination of the machine guide beam 5 does not strike the 
light-sensitive elements of the third and last measuring surface 18 and 
must be aligned correspondingly by sliding and/or swivelling. Such a 
displacement is represented in FIG. 4. The axis 19 of the beam 5 
penetrates already slot 12 of the first measuring surface 11, but strikes 
out of the slot 15 of the second measuring surface 14. In the displacement 
represented in FIG. 4 the both light-sensitive elements 13 of the first 
measuring surface 11 give already a signal, but only one light-sensitive 
element 16 on one side of slot 15 of the second measuring surface 14 will 
be able to give a signal. The third measuring surface 18 the beam does not 
strike and therefore no signal will occur in the light-sensitive element 
17. In such a displacement the direction of the required swivelling of 
housing 2 about axis 3 results immediately in order to ensure that also in 
the second measuring surface 14 the light-sensitive elements on both sides 
of slot 15 are struck. As soon as this swivelling is achieved, the correct 
position results from the further occurrence of a signal in the third 
measuring surface 18. The distance f between the first and the second 
measuring surface 11 and 14 is chosen so that with a value of angular 
deviation .alpha. assumed or permissible as a maximum is just struck. This 
condition is complied with if this distance f be 
EQU f.ltoreq.(a)/(sin .alpha.). 
By swivelling housing 2 about axis 3 the correct position can be taken and 
from the swivelling angle required for this the measured angle of 
displacement of the machine results immediately. The measuring surfaces 11 
and 14 are herein shaped as slotted diaphragms with essentially vertical 
slot axis and the receiver elements represented in FIG. 3 and 4 in a plane 
of cross-section are arranged in pairs on both sides of the longitudinal 
median plane of the slots. This is explained more precisely in FIG. 5 and 
6, in FIG. 5 being represented a measuring surface 11 which could be used 
as a measuring surface 14 as well. The diameters of the receiver elements 
are marked with g and the distance a in the direction at right angles to 
slot 12 measured so that the diameter e of the striking spot of the guide 
beam can admit to an opposed pair of receiver elements 13 each. In height 
direction of slot 12 a number of such receiver elements 13 are provided, 
wherein the distance of those receiver elements 13 successive in height 
direction is chosen again with a. In order to ensure that in each height 
position at least one pair of receiver elements 13 opposed to each other 
in relation to slot 12 can be admitted to by the guide beam, this distance 
a must be chosen so that the diagonal of the quadrangle formed by four 
neighbouring receiver elements 13 is smaller or equal to the diameter of 
the striking spot of the guide beam. With regard to the diameter g of the 
single receiver elements a results as 
##EQU1## 
In case a distinction of single positions in height direction is not 
necessary, the receiver elements can be shaped as is represented in FIG. 
6. Herein two elongated receiver elements 20 are arranged, which can be 
located on both sides of a slot. The embodiment according to FIG. 6 is 
favourable particularly for the third measuring surface 18, which the 
guide beam 5 with a clear width b corresponding to the width of the slot 
of the second measuring surface 14 located in front can strike. Between 
the measuring elements 20 a distance with breadth h is provided, which is 
smaller than the clear width b of the slotted diaphragm located in front 
of it. When both receiver elements 20 give a signal, the correct position 
of device 1 results from it. The receiver elements 20 are herein developed 
as double field sensor, the both receiver fields of which are located in a 
distance of several .mu.m. 
For detecting a vertical deviation of the machine it is sufficient to fit 
to the front face 6 a vertical scale when laser or light beams are used. 
Determination of the vertical deviation can be effected also by the 
superposed receiver elements 13 on one side of the slot 12 within the 
measuring surface 11 being analyzed separately, whereby the effort for 
analysis and the expenditure for the receiver elements are increased. 
A schematically particularly simple analysis of the signals results in the 
representation according to FIG. 7 from signal lines of the receiver 
elements of each side of the measuring surfaces being conducted together 
to an analyzing circuit. For this case a switching arrangement 21 for 
determining the direction of the required correction and an AND - gate are 
provided. As soon as both lines of the receiver elements give a signal, 
correction can be stopped because of the AND - gate 22. When the receiver 
elements of a measuring surface 11 superposed in height position are 
grouped, as is represented in FIG. 8, further logical statements can be 
made. In the representation according to FIG. 8 three receiver elements 13 
at a time superposed in vertical direction of the slot 12 are grouped and 
their signal lines conducted separately for both sides to an OR - gate 23. 
The rest of the switching arrangement with the AND - gate and the device 
for determining the required correction of direction 21 remains untouched 
herein. In vertical direction a gradual follow - up is made possible if 
the single signals of the superposed groups 24, 25, 26, and 27 are 
analyzed separately. When using a switching arrangement corresponding to 
FIG. 8 for two measuring surfaces 11 and 14 located one behind the other 
also a statement on the angle of deviation or gradient is possible, if the 
guide beam is admitted to another group of receiver elements in a 
measuring surface than in the following second measuring surface. 
A particularly simple embodiment of a measuring surface 11 with which 
distinction in height direction is not possible though is represented in 
FIG. 9. The receiver elements 13 are herein formed by the free ends of 
light wave conductors 28 and a common signal receiver for the light wave 
conductors of the receiver elements 13 to one side of slot 11 is provided. 
Such an embodiment according to FIG. 9 can be used for all measuring 
surfaces, doing without analysis in height direction. Such light wave 
conductors 28 offer the advantage that they can have a very small diameter 
and this can be of great significance for the exactness especially in the 
third measuring surface. Light wave conductors can also be placed very 
exactly in drill holes.