Abstract:
The shock protection device prevents damage to optically and micromechanically acting gyroscopes. The gyroscope or precision instrument to be protected can be located in an inner housing shell which is spaced apart from an outer housing shell by elastic elements, and is thereby protected against shock. The inner housing shell can be brought temporarily into accurate mechanical contact with the outer housing shell by an electromechanical device. The spatial orientations of the inner and outer housing shells then correspond with high precision. In a further embodiment of the invention, the electromechanical device can be used precisely conversely to deactivate an existing shock protection and temporarily to bring about direct contact between a sensing element and an object to be checked on the occasion of a measuring operation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a shock protection device for position measuring, probes or gyroscopes, in particular those which are equipped with an optical gyroscopic system or with a mechanical oscillator. 
     2. Description of the Related Art 
     A shock protection system for position measuring probes of the type, as described in the German patent references DE 19800534.2 or DE 19546405.2, is not known. The devices used by the person skilled in the art in order to protect chronometers or electric precision instruments such as, for example, galvanometers against shock cannot be used in this regard to provide shock protection for position measuring probes or gyroscopes. 
     The problem on which the invention is based consists in the following: when use is made of position measuring probes, they have to be protected against excessive shocks or accelerations. This is based, in particular, on the sensitivity of the components to such shocks. Substantial repair costs can therefore arise through inadvertently dropping such instruments. On the other hand, the position measuring probes must be applied to a surface to be measured in a defined fashion, that is to say with mechanical precision without backlash or damaging flexibility. These aspects oppose one another to a certain extent, since it is not possible to fit conventional cushioning to the probes discussed here without adversely affecting their measuring accuracy. 
     SUMMARY OF THE INVENTION 
     In accordance with the invention, the present problem is solved by providing the position measuring probes a shock protection which is temporarily deactivated on the occasion of a measuring operation to be carried out, or is made available only proportionally. For this purpose, in a first basic embodiment, the shock protection has the following features: 
     an outer housing shell is present which can be applied to a surface to be measured in a defined fashion, 
     at least one inner housing shell is present which encloses one or more sensors or instruments, in particular angular position sensors, 
     the inner housing shell is spaced apart by one or more cushioning or shock-absorbing elements with reference to an outer enclosing housing shell or a bearing surface during a time phase in which anti-shock functions are prioritized, 
     the inner housing shell is brought into self-closed mechanical contact with, reference to an enclosing outer housing shell or a bearing surface during a phase for detecting measured values, and 
     the inner housing shell can be brought into self-closed mechanical contact with the outer shell or a bearing surface by means of an electromechanical device or manually. 
     In a second basic embodiment, the shock protection according to the invention for a position measuring probe has the following features: 
     the position measuring probe can be brought into a first operating state by means of a device which can be actuated manually or by motor, in which it is protected completely against shocks acting from outside, but in which it cannot be used for the purposes of position measurement, and 
     the position measuring probe can be brought into a second operating state by: means of the device which can be actuated manually or by motor, in which it can carry out position measurements, but during the period of which it is not completely protected against shocks acting from outside. 
     It is now possible in accordance with the invention to protect position measuring probes and gyroscopes based on optical gyroscopes, specifically fiber-optic gyroscopes, and those having one or more mechanical vibrators (oscillators), against shocks during transportation, during operation and also when being applied to a surface to be measured. Such surfaces can specifically be the cylindrical surfaces of rollers such those used to produce films, foils, sheets and paper materials, and which must have a highly accurate parallelism. The invention is therefore, particularly suitable for carrying out a very accurate measurement of the parallelism of such rollers without there being a large risk of inadvertently damaging the relatively costly measuring apparatus used by incorrect deposition, mounting or by dropping. 
     In accordance with the first basic embodiment, the invention is based on the fact that instead of a single housing for appropriate devices, provision is now made of a housing which has an inner and an outer shell. The two shells are spaced apart from one another in the inactive state of the probe by a special cushion. A measuring system located inside the inner housing shell is thereby protected elastically against shocks. Not until shortly before the determination of a measured value and after the measuring probe has been brought into a measuring position of interest is an electrically operated device used to ensure that the inner and outer shells are brought into mechanical contact with one another which is defined with high accuracy. Immediately after the measured value is taken, it is ensured that the mechanical contact between the two shells is released again. Instead of the electrically operated device which makes the mechanical contact, it is also possible to provide a device which operates similarly and is to be actuated manually and which can be configured more simply in structural terms. A device operated by compressed air can also be provided for comparable problems requiring a relatively large housing. A typical cycle of a measuring operation thus consists in that the measuring probe is applied to a surface to be measured, a trip element or switch is then actuated by means of the electrically operated device to produce precise mechanical contact between the two shells, and an electronic system (preferably located in the interior of the two shells) then senses and electronically evaluates the positional and/or angular values of interest, and thereafter the mechanical contact between the two shells is released again by the electrically operated device. The measured values obtained are further used and evaluated after these steps. 
     In accordance with the invention, mechanical contact is made between the inner and outer shells preferably by means of a contact-making movement in the direction of one of the spaced diagonals of these shells, with the result that the periphery of the inner shell can make contact with at least three bearing points on the inside of the outer shell. The outer shell acts in this way to a certain extent, as a mechanical guide prism for the inner shell. It is possible in accordance with the invention to provide any desired elastic materials as cushioning for the purpose of absorbing shocks on the said inner shell with respect to the outer shell. However, it is advantageous to provide expanded silicone materials as cushioning, since not only can these be used over a large temperature range and are virtually nonflammable, but their elastic properties also show no particularly pronounced temperature response. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows the fundamental principle of a first basic embodiment for a device acting in two dimensions, and 
     FIG. 2 shows the fundamental principle of a second basic embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Although the arrangement shown in FIG. 1 displays shock protection in two directions, it can be used directly to produce a device working correspondingly in three dimensions. FIG. 1 shows, as a representation of a section, the interspace between the shells which is fitted with an electromechanical device. A representation of those corners or edges of the position measuring probe which are not used to make mechanical contact between the shells is dispensed with. In detail, reference numeral  1  denotes an outer shell of the housing according to the invention for a position measuring probe or for a precision instrument, while an associated inner shell is identified by reference numeral  3 . If they are not in direct mechanical contact with one another, the two shells  1  and  3  are spaced apart mutually from one another by one, preferably a plurality of elastic cushioning elements  10 , and with a prescribed elasticity. They thereby protect an arrangement situated in the inner shell  3 , specifically a gyroscope, against mechanical shock. A cushioning element  10  preferably comprises of an expanded elastic material or an elastomeric material. It preferably has an approximately semicircular cross section and is fixed on the inner shell  3  by means of a heat-resistant adhesive layer  11 . In order to achieve a sufficient spring excursion for the cushioning element  10 , the latter is preferably inserted into depressions  12  which are recessed into the inner shell  3  and thereby define local projections  9  which serve as bearing surfaces for making mechanical contact. A relative movement of the inner shell  3  in the direction of the outer shell  1  can thus take place only against a spring force. The damping properties of the cushioning element  10  can be varied depending on whether the elastic material which is used in the element is specified rather as being open-cell or as being solid. 
     The elastic connection between the inner shell  3  and outer shell  1  can be undone temporarily by activating the electromechanical device  4  (with terminal contacts  5  and  6 ) located in a corner of the outer housing  1 . The electromechanical device  4  is fixed on the outer shell, for example, by means of a fixing bracket  2 , and is preferably constructed as a low-volume DC linear motor. The push rod  7  thereof can either draw or push the inner housing  3  in the direction of the arrowheads A or B by means of a spring element  8 , depending on the type of power supplied. Thus, if the inner housing  3  is drawn in the direction of the arrowhead A, the result of this is that the projections  9  are applied sequentially (possibly simultaneously) to the inner surfaces of the outer shell  1 . As a result, the shells  1  and  3  are in an exactly defined position relative to one another, and the spatial position and orientation of the outer shell  1  is transmitted to those of the inner shell  3 . In this phase, which usually corresponds to a measuring phase, the shock-reducing effect of the cushioning elements  10  is eliminated, as is that of the elastic element  8 . After termination of a measuring operation, the inner shell  3  is pushed back again by the electromechanical device  4 . The cushioning elements  10  thereby once again take over the function of providing spacing and reducing shocks between the outer and inner shells. 
     If it is to be possible to bring the outer and inner shells into contact with one another in all three coordinates of space, it is advantageous to provide the drawing/pushing direction of the electromechanical device  4  approximately in the direction of the., corresponding space diagonals of a shell. Success is achieved in this way in creating an exactly defined relative position between the inner shell  3  and outer shell  9 . 
     A second solution of the above-named problem is provided in accordance with FIG. 2, which shows another device according to the invention in a cross-sectional view: 
     Located inside an outer shell  101  serving as protection against mechanical effects, is an instrument panel  102  which holds or supports a measuring instrument susceptible to shock, for example a gyroscopic system  105  (drawn schematically). The gyroscopic system can also comprise a plurality of gyroscopes not shown aligned orthogonally relative to one another. The outer shell  101  is closed almost on all sides, but has an opening in the form of a cutout  103  on the bottom surface and the lateral surfaces (opening in the bottom surface not identified in more detail). Owing to the cutout  103 , the instrument panel provided with a prismatic bearing surface  104  can, if required, be brought into direct and highly accurate mechanical contact with a cylindrical roller not shown situated below the cutout  103 , or with another object to be measured. However, the position of the instrument panel  102  shown in the figure represents a first operating state of the device according to the invention, in which protection is provided against shocks acting from outside by shock-absorbing elements such as, for example, an expanded plastic cushion  106 . In order to be brought from this position into mechanical contact with a cylindrical roller located therebelow, it is necessary for the instrument panel  102  to be lowered. Provided for this purpose is a device which is operated manually or by motor and comprises, as shown, for example a screw  101  and a coupling plate  1013  provided with a threaded bore  1012 . Screw  1011  can be turned in a right-handed or left-handed fashion by the rotary button  109  and/or an electric motor drive (by motor  1010 ), with the result that it is possible to effect a variable spacing of the coupling plate  1013  relative to the underside and topside of the outer shell  101 . Coupling plate  1013  preferably has a conical surface  1014 , so that the instrument panel  102  can be raised or lowered by means of a shock-absorbing element, essentially permanently connected to the latter, in the form of an expanded plastic cushion  1016  and the conical surface  1015  thereof. With the screw  1011  tightened, the instrument panel  102  is therefore brought into a cushioned rest position in which it is sufficiently protected against damaging accelerations by means of the combined anti-shock action of the expanded plastic cushions  106  and  1016 . As shown, in this position, a beveled bearing surface  108  of the instrument panel is situated directly on a beveled edge  107  of the expanded plastic cushion  106 , with the result that an anti-shock action is effected in at least two directions in space. 
     By means of a connecting line  1021 , the motor  1010  can be actuated by a schematically represented combination  1020  comprising an energy supply and a measuring and control computer. This combination  1020  is connected without wires or, equally, by means of a connecting cable  1022  to the instruments, in order to provide power and/or transmission of measured or controlled variables. 
     Although not shown in the drawing, it may be seen that upon contact being made with an object (not shown) to be measured the complete protection of instruments such as, for example, a gyroscopic system  105 , in particular a laser gyroscopic system, against shocks acting from outside is undone after lowering the instrument panel  101 , in an essentially linear way, by means of the screw  1011 , threaded bore  1012  and coupling plate  1013 . In accordance with the invention, it is possible to provide a spring excursion of 5 to 25 mm for the relative movement between the gyroscope housing and protective housing by means of the anti-shock device or buffer. The protective housing can additionally be equipped with an electronic interface system, a keyboard or an indicating device/display. In addition to or instead of a gyroscopic system  105 , it is possible to provide on the instrument panel  102  an inclinometer which can be read off usually or electronically. 
     Moreover, the shock of the contact between the instrument panel and an object to be measured can be reduced by providing in the instrument panel additional spring elements which, however, are pressed back in the case of complete contact into bores or cutouts provided, and then no longer influence the actual measuring operation. 
     The shock protection described above is preferably used in the industrial application of laser gyroscopes in connection with the checking of the parallelism of roller arrangements which are used in producing films, foils, sheets or paper material.