Geometrical instruments – Straight-line light ray type – Alignment device
Reexamination Certificate
1999-03-10
2002-12-17
Gutierrez, Diego (Department: 2859)
Geometrical instruments
Straight-line light ray type
Alignment device
C033S291000, C033SDIG002, C356S250000, C356S149000, C073S514230, C073S514220
Reexamination Certificate
active
06493952
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a measuring device subjected to gravitational forces and including at least one laterally oscillating, pendulously suspended support structure for supporting, e.g., an optical device. In particular, the present invention relates to a suspension for such a device.
2. Description of the Prior Art
In many scientific and technical applications, the gravity force acting on a measuring system plays not inconsiderable role. In many cases, the action of the gravity force is used directly or indirectly for solving a measurement problem Inclinometer, horizon sensor, accelerometer, leveling devices are examples of measuring devices influenced by gravitational forces. In particular, it is often necessary to precisely align horizontally and/or vertically a measuring device, a display device, an optical device and the like. In particular, optical devices for projection of marks over large distances put high demands to a leveling device in order to keep a projection error over a large distance as small as possible. For some time, in constructional industry and in building technology, apparatuses, which contain optical devices for transmitting marks over large distances, e.g., with a light beam, in particular, with a laser beam, are used. With the help of an optical device, which is contained in an apparatus, a laser beam is splitted, e.g., in two or three laser beam components extending, respectively, perpendicular to each other. With such an optical device, an apparatus for displaying right angles and for laying out horizontally and/or vertically extending marks can be formed.
The prior art discloses different solutions for aligning a laser beam manually or automatically in order to insure an exact horizontal and/or vertical course of a laser beam in case of uneven surfaces. One of the known solution consists in that a support plate for a light source and an optical device, which is arranged in the housing of an apparatus, is manually adjusted horizontally and/or vertically in a desired manner with set screws and level indicators, e.g., bubble or water levels. This solution is constructively relatively expensive. Besides, manual adjustment is laborious and often cannot be effected with a desired precision. The adjustment can be simplified and a high adjustment precision can be achieved by the automatization of the adjustment process, e.g., by providing servomotors connected with the level indicator. However, this solution is associated with relatively high costs, connected with the provision of necessary mechanical and electronic means, and increases the overall cost of the measuring apparatus. In addition, leveling devices equipped with servomotors require a relatively large mounting space and, therefore, are used primarily with large precision apparatuses, e.g., with rotating constructional lasers.
U.S. Pat. No. 5,459,932 discloses a laser indicator which emits at least two mutually perpendicular laser beam. The disclosed indicator is used for transmission of horizontal and/or vertical marks or right angles. With this apparatus, e.g., components can be exactly aligned and controlled horizontally and vertically or arranged at a right angle. The apparatus has relatively small dimensions. The action of the leveling device for horizontal and/or vertical alignment of the laser beams is based on the use of gravitational forces. To this end, the light source and the optical device are arranged on a platform which is attached, in a pendulum-like manner, to a wire suspended from the apparatus housing. The pendulously suspended platform has two lateral degrees of freedom and, thereby, can by itself compensate unevenness of the support surface of the apparatus due to action of the gravitational forces. Damping of the pendulously suspended platform is effected, e.g., with a magnetic means. To this end, magnetized elements arranged on the platform cooperate with magnets arranged in the apparatus housing in the vicinity of the platform. To prevent breaking of a relatively brittle wire suspension under impact loads, at least one spring element is provided between a point, at which the wire is attached to the housing, and a point at which it is connected with the platform. The spring element, e.g., a coil spring, damps all of the impacts applied to the housing and reduces the danger of the wire suspension being broken. The spring element can be serieusly connected with the wire suspension but also can be used instead of the wire suspension. For power supply, there are provided thin conducting wires which connect a power source arranged in the housing with the light source. The conducting wires have a relatively small mass and are arranged in such a way that their influence on the pendulously suspended platform is minimal. Nevertheless, the stiffness of the wire suspension and the mass of the conducting wires create a torque which prevents an exact horizontal and/or vertical alignment of the platform. The insignificant position errors are compensated with optical means.
Accordingly, an object of the present invention is to improve the apparatus or device described in the above-mentioned U.S. Patent so that the susceptibility of the pendulously suspended platform to impacts is further reduced. A further object of the present invention to prevent, to a most possible extent, interfering oscillation mods such as particularly occurring in wire suspensions. The pendulous suspension of a platform, which supports the light source of the laser and the optical device, should be modified so that preconditions for reducing the influence of the torque of the conducting wires on the pendulous suspension are created. The modified pendulous suspension should be capable of being produced in a simple and cost-effective manner.
SUMMARY OF THE INVENTION
These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing a measuring device subjected to gravitionaly forces and including at least one laterally oscillating, pendulously suspended, support structure for supporting at least one of measuring means and optical means, and means for suspending the support structure and including at least one hinge formed as a tape hinge. Tape hinges have, as a result of their lateral tensioning under the action of impact loads, a greater rigidity than a springy pendulous wire or thread suspension a cross-section of which approximates a point. By forming the hinge as a tape hinge, a bendable region is formed in the hinge which is characterized by a fixed laterally extending neutral axis in a narrow predetermined longitudinal region of the hinge. Further, with regard to available materials, a greater selection of material exists for tape hinges than is the case with wire or thread suspensions. Tape hinges despite their relatively greater rigidity, have a high flexibility and a small base stiffness.
During manufacturing of the tape hinge, the oscillation damping aspect is taken care of to a certain degree by the geometrical design of the hinge section. Thereby, additional damping means, e.g., magnetic means, can be reduced in size. The technology for producing the tape hinges is cost-effective and has proved itself. The articulation region of the suspension can be prefabricated with a reproducible stiffness and need not be first formed during the mounting, as is the case with suspension wires, which may result, dependant on the quality of the mounting, in that the hinge stiffness would differ from hinge to hinge. Because the hinge link is prefabricated, it can be easily mounted in the device.
In particular, tape hinges are suitable for a completely automatic mounting, which further reduces manufacturing and assembly costs of a device equipped with a leveling device according to the present invention.
The suspension can, e.g., include a rubber-like material at least in the articulation region. According to a preferred embodiment of the present invention, which is particularly adapted for a mass production
Kousek Heinz
Piske Wilfried
Waibel Reinhard
Gonzalez Madeline
Gutierrez Diego
Hilti Aktiengesellschaft
Sidley Austin Brown & Wood LLP
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