DE29805709U1 - Optical measuring and display device, in particular laser device - Google Patents

Description

Ludwig Aumann Augsburger Strasse 86473 Ziemetshausen

Mister

Jürgen Grötsch Ernst-Mezger-Strasse 86316 Friedberg

Representatives: Patent attorneys

Dipl.-Ing. H.-D. Ernicke Dipl.-Ing. Klaus Ernicke Schwibbogenplatz 2b D-8 6153 Augsburg

Date: 27.03.1998

File: 500-218 er/sw

AAl DE-G 298 05 709.3

Note: Ludwig Aumann, Jürgen Grötsch

02.07.1999 he/she

DESCRIPTION 5

Optical measuring and display device, in particular laser device

The invention relates to an optical measuring and display device, in particular a laser device, with the &iacgr;&ogr; features in the preamble of the main claim.

Such a laser device is known from DE-A-44 42 224. It has a rotating laser head that is rotated by a stepper motor via a backlash-free toothed belt drive with a gear ratio of approx. 2:1.

A similar laser device is also disclosed in US-A-5,621,975. The rotating laser head is rotated by a DC motor via a high-reduction and multi-stage belt drive. In both previously known laser devices, problems with positioning accuracy can arise in rough construction site conditions.

Another laser device is known from EP 0 468 677 A2. It has a beam generator, in this case a laser head, which directs the laser beam onto a pivoting mirror with a motorized rotary drive. A measuring device for its rotary movements is attached to the mirror. Such laser devices with a rotating mirror are expensive and complex. They are also sensitive to impact and other environmental influences. This makes them less suitable for construction sites.

It is therefore the object of the present invention to provide an optical measuring and display device that is suitable for construction sites and the operating conditions prevailing there.

is more suitable.

The invention solves this problem with the features in the main claim.

The rotary drive for the jet generator has a backlash-free cable gear with a correspondingly high gear ratio. The high resolution required by the device is achieved via the cable gear and its backlash-free nature. This design is particularly robust and cost-effective. The measuring and display device according to the invention is therefore also particularly economical.

A large amount of play is an advantage for the desired high resolution and measurement or display accuracy. The special winding form of the cable on the motor shaft eliminates slippage in the drive area. On the other hand, one or both cable ends are attached to the rotary bracket under a suitable pre-tension, e.g. using a tension spring. When winding the cable on the motor shaft, it is particularly advantageous if the cable is fixed in the middle position via a transverse hole and if the cable windings on both sides of the motor shaft run in opposite directions. This means that the cable is always unwound in both directions of rotation. The desired transmission is achieved via the diameter differences between the motor shaft and the cable pulley of the rotary bracket.

The rotary drive preferably has a motorized stepper drive, preferably an electric stepper motor. The device according to the invention has a low power consumption and operates on a battery supply. This improves the usability for construction site operation and makes the device independent of a local power supply.

The measuring and display device can be placed in the water with several at least partially adjustable supports in conjunction with a suitable leveling device, or aligned in the desired angle position. The device can have an adjustable frame to increase the range of applications. This means that it can be positioned in at least two different angles.

&iacgr;&ogr; The measuring and display device according to the invention has, in addition to a suitable display or a screen, preferably also an input device, in particular a keyboard, with which the beam generator, preferably a laser head, can be controlled.

The optical measuring and display device according to the invention can be used to measure and mark angles at any location, preferably on construction sites. In addition, cracks and distances can be displayed using the moving light beam, in particular the laser beam. The device according to the invention can be used as a replacement for so-called laser spirit levels and for other digital angle measuring devices. It combines their functions in one device.

Further advantageous embodiments of the invention are specified in the subclaims.

-A-

The invention is illustrated by way of example and schematically in the drawings. In detail:

Figure 1 and 2: The optical measuring and display device

in standing position with a laser beam moving parallel to the support in side view and folded top view,

Figure 3 and 4: the device in lying position

with vertical laser beam in side view and folded top view,

Figure 5: a bottom view of the device from

Figure 1-4 and

Figure 6: an enlarged individual representation

of the laser head with rotary drive.

In the drawings Figures 1-5 an optical measuring and display device (1) is shown, which is preferably designed as a laser device. It generates a rotating light beam, preferably a laser beam, which can move back and forth in a circular arc in a controlled manner. Angles on buildings, objects, etc. can be measured and marked using the laser beam (17) and the optically visible points of impact. The laser beam (17) can be aligned to certain predetermined angles set on the laser device (1) and then used to mark these angles on the objects mentioned with reference to the position of the laser device (1). Conversely, the laser beam (17) can also be used to optically scan certain points on distant objects and then to rotate the laser beam.

(17) the angle between the marking and impact point can be measured. The laser beam (17) can also be rotated back and forth continuously, marking cracks or stretches of a certain length on the objects across the series of impact points. Such stretches can also be measured.

The measuring and display device (1) is particularly suitable for use on construction sites where no external power supply is available and where the device is subject to rough handling.

The laser device (1) has a housing (2) and a preferably adjustable frame (3) which is provided with several supports (12, 13, 14). A leveling device (15) can be present on the housing (2), which in the embodiment shown consists, for example, of (2) spirit levels aligned at right angles to one another.

The device (1) can be positioned in preferably (2) or more angular positions using the adjustable frame (3). For this purpose, the frame (3) consists of two horizontal arms that can be rotated around the longitudinal axis relative to the housing (2). At the ends of the arms there are adjustable supports, which consist, for example, of support blocks with a spindle and a hand wheel. Two fixed supports (12, 13) are arranged on the housing (2), which form the fixed point relative to the adjustable supports (14) in the respective angular position. This means that the device (1) can be set up and leveled in the angular positions shown in Figures 1 and 2, or 3 and 4, using a three-point support. Figures 1 and 2 show the device (1) in a standing position, with the laser beam (17) aligned parallel to the support, or horizontally when leveled accordingly. In Figure 3 and the device 1 has a lying position with a laser beam (17) aligned transversely to the support or vertically.

Figure 2 shows the beam area (20) of the laser beam (17), the arc angle of which is preferably at least 180°, e.g. 270°.

The housing (2) also has a display (16), preferably a multi-part display. In addition, an input device (29) is preferably arranged adjacent to the housing (2). This consists, for example, of a membrane keyboard. It can have, for example, four buttons for switching on and off, for entering angles in steps to the left and right and for executing commands.

The measuring and display device (1) has an optical beam generator (4), which is preferably designed as a laser head. Alternatively, it can also emit any other optical beam, which at least lights up when it hits an object or is visible in another way. The laser head (4) is rotatably mounted in the laser device (1). For this purpose, it has a rotary holder (8) and a high-ratio motor rotary drive (5). These parts are shown in more detail in Figure 6. The rotary holder (8) and the rotary drive (5) have parallel axes (18, 19) and are coupled to one another via a play-free cable gear (9).

The rotary holder (8) preferably has a cylindrical pulley (23) at the upper end, over which the rope (10) of the rope gear (9) is guided. A block-like head holder is attached to the underside, to the underside of which the laser head (4) is attached. The head holder can also be cylindrical and have a transverse flattening at the front end, where the laser beam (17) emerges.

The rotary drive (5) has a motorized stepper drive (6), which is preferably designed as a digital, electric stepper motor.

The cable (10) of the cable gear (9) is wound around the motor shaft (7) that protrudes downwards from the stepper motor (6). The gear ratio is determined by the diameter differences between the motor shaft (7) and the cable pulley (23). The gear ratio is preferably at least 9:1 or higher and can depend on the stepper drive (6).

The stepper motor (6) is controlled by digital signals that send current pulses to the motor windings and, by switching the motor strands appropriately, rotate the motor (6) by a fixed small angle. These motors can be used to carry out positioning tasks with high precision and reliability. The stepper motor (6) can, for example, have a step angle of 1.8° or 0.9° in full-step mode. With the 200 or 400 steps/revolution mentioned, there is also the option of half-step control, which leads to a doubling of the number of steps. The stepper motors (6) with 200 or 400 steps/revolution have almost identical characteristics when considering the number of steps/second. They reliably achieve around 4,000 steps/second. This is 20 revolutions per second for the 200 motor and 10 revolutions per second for the 400 motor. At these speeds it is ensured that the applied step pulses are also executed, even if the torque characteristics of a stepper motor decrease with increasing speed.

With an assumed accuracy of approx. + 1 mm/m. range, a resolution of 0.1 angular degrees is achieved. This is a practical value and is equal to or better than other known devices. By using a laser beam that is still clearly visible and sharply imaged at 10 m, a positioning accuracy of 2*r*p/360*10 is achieved. This results in a smallest

The distance to be mapped is 17.5 mm long. The errors that occur are not additive. Division and rounding errors in the software are also not additive, so that the accuracy mentioned is maintained at every angle.

In the preferred embodiment, the cable gear (9) used achieves a corresponding gear ratio to achieve a resolution of 3,600 positions for 360°. For stepper motors with 200 steps/revolutions, a gear ratio of 18:1 is used, and for 400 motors, 9:1, for example. In the preferred embodiment, a 400 motor with a gear ratio of 10:1 is used. This results in reliable positioning in the 1/10° range. Odd gear ratios, which can occur in any production process, are reported in the software's calibration mode and are corrected in the final display. The achieved speed of 1 second for 3 60° is practical and sufficient. The laser head 4 preferably covers an arc angle of approx. 270°, although in practice smaller angles in the range of up to 100° are usually used. This design of stepper motor (6) and cable gear (9) results in relatively small and easily manageable diameters for the motor shaft (7) and rotary holder (8).

The cable gear (9) is free of play and transmits the motor rotations without slip and with the specified gear ratio to the rotary bracket (8) and the laser head

(4) . The absence of play is achieved by winding the rope (10) on the motor shaft (7) without play and by securing the rope ends (24) to the rope pulley (23).

—Q—

In the preferred embodiment, the cable (10) has a finite length. The cable ends (24) are laid around the cable pulley (23) and fixed in the middle angle position to the cable pulley end opposite the motor shaft (7). One or both cable ends (24) are connected to a tensioning element (21), preferably a tension spring, which tightens the cable (10) and holds it to the cable pulley (23) without play. The highly stretch-resistant cable (10) is preferably designed as a wire cable, but can alternatively be designed in any other way. It can also be, for example, a band, a belt or any other suitable flexible and tensile element.

On the other side, the cable (10) is wound several times around the motor shaft (7). The cable is preferably inserted through a transverse hole (22) in the motor shaft (7) and then wound up on both sides over several turns (26,27) along the motor shaft (7). The turns (26,27) are wound in opposite directions. In the middle position of the laser head (4), the turns (26,27) are the same size. Due to the opposite winding, when the laser head (4) or the rotary holder (8) rotates, the same amount of wire is wound up on one turn (26,27) as is unwound on the opposite turn (27,26). This means that when the rotary holder (8) is rotated to the right or left, there is no change in the cable length between the motor shaft (7) and the cable pulley.

(23) . Different rope tensions or rope sag are reliably avoided.

To measure or control the rotary movements, the stepper drive (6)' is connected to a measuring and display device (25). This can, for example, have one or more rotary encoders connected to the motor shaft (7) for measuring or setting the angular positions. The

- 10 -

Preferably a digital stepper motor (6) can be controlled and positioned with the specified pitch in steps. The transmission of the cable gear (9) ensures a high resolution.

The measuring and evaluation device (25) is preferably equipped with one or more microprocessors and corresponding memories for data, programs, etc. A battery unit is provided as the power supply (28),

&iacgr;&ogr; which supplies both the measuring and evaluation device (25) and the stepper drive (6). The device (1) is therefore at least temporarily independent of an external power supply. The battery (28) can be recharged.

The computer (25) is connected to the display (16) and to the keyboard (29). It can also have additional interfaces for input and output of data, e.g. a serial interface for connection to an external computer, a data storage device or the like. In addition, remote control can also be implemented via such an interface. The interfaces mentioned are not shown for the sake of clarity.

In the embodiment shown, the laser head (4) is arranged in the lower housing part in a chamber which has the large housing opening (30) on the front side. This housing opening (30) is bordered by lateral slots (11) through which the laser beam (17) can pass at the rotary holder (8). This housing design means that the laser head (4) with its rotary holder (8) is accessible from the front for maintenance, assembly and adjustment work. On the other hand, it is largely protected by the housing walls against impact, dirt and other impairments. The housing (2) can also have an opening on the underside, e.g. a

Circular cutout (see Figure 5) through which the cable gear (9) and the motor shaft (7) are accessible. In an alternative design, the housing (2) can also be largely closed, with only circumferential slots (11) left free for the laser beam (17). The required housing openings can then be closed by covers or the like.

Modifications of the embodiment shown are possible in various ways. Firstly, the housing (2) with the frame (3) and its parts can be designed in any way. Furthermore, the stepper drive (6) can also be designed in any other suitable way.

- 12 REFERENCE SYMBOL LIST

1 measuring and display device, laser device

2 Housing 3 Frame

4 beam generators, laser head

5 Rotary drive

6 Stepper drive, stepper motor

7 Wave

8 Rotating bracket

9 Cable gear

10 Rope

11 Slot

12 Support, fixed 13 Support, fixed

14 supports, adjustable, spindle

15 Levelling device, spirit level

16 Display

17 Laser beam

18 Rotary axis, laser head

19 Rotary axis, drive

20 Beam area

21 Tensioning element, tension spring

22 Bore

23 Pulley

24 Rope end

25 Measuring and evaluation device, computer 2 6 winding

27 winding

28 Power supply, battery

2 9 Input device, keyboard

30 Housing opening

Claims (17)

- 13 CLAIMS FOR PROTECTION 1.) Optical measuring and display device, in particular a laser device, which has a beam generator with a rotary holder, a motorized rotary drive and a backlash-free gear as well as a measuring device for the rotary movement and a display, characterized in that the rotary drive (5) has a backlash-free, high-ratio cable gear (9) with a stretch-resistant cable (10) of finite length, which is wound around the motor shaft (7) and whose cable ends (24) are attached to the rotary holder (8) of the beam generator (4) with a tensioning element (21). 2.) Device according to claim 1, characterized in that the rope (10) is designed as a wire rope. 3.) Device according to claim 1 or 2, characterized in that the cable gear (9) has a gear ratio of 9:1 or greater. 4.) Device according to claim 1, 2 or 3, characterized in that the rotary drive (5) has a step drive (6). 5.) Device according to one of claims 1 to 4, characterized in that the step drive (6) has a digital electric stepper motor. 6.) Device according to one of claims 1 to 5, characterized in that the step drive (6) has a battery-operated power supply (28). - 14 - 7.) Device according to one of claims 1 to 6, characterized in that the motor shaft (7) has a smaller diameter than the pulley (23) of the rotary holder (8). 5 8.) Device according to one of claims 1 to 7, characterized in that the rope (10) is wound several times on the motor shaft (7) and is held free of play. 9.) Device according to claim 8, characterized in that the cable (10) is held on the motor shaft (7) by a transverse bore (22) and several windings (26,27) arranged on both sides of the bore (22). 10.) Device according to claim 8 or 9, characterized in that the turns (26, 27) are wound in opposite directions. 11.) Device according to one of claims 1 to 10, characterized in that the step drive (6) is connected to a measuring and evaluation device (25) and a display (16). 12.) Device according to one of claims 1 to 11, characterized in that the measuring and display device (1) has a frame (3) with several at least partially adjustable supports (12, 13, 14). 13.) Device according to one of claims 1 to 12, characterized in that the measuring and display device (1) has an adjustable frame (3) and can be positioned in at least two different angular positions. - 15 - 14.) Device according to one of claims 1 to 13, characterized in that the measuring and display device (1) has a leveling device (15) that displays in one or more axes. 15.) Device according to one of claims 1 to 14, characterized in that the beam generator (4) is designed as a laser head. 16.) Device according to one of claims 1 to 15, characterized in that the jet generator (4) is arranged in a housing part with a front housing opening (30) and adjacent side slots (11). 17.) Device according to one of claims 1 to 16, characterized in that the measuring and display device (1) has an input device (29), in particular a keyboard.