Abstract: A coupling apparatus for a length measuring instrument is disclosed. The length measuring instrument includes a scale, which defines a division, and a scanning unit. The scale is connected to a first object and the scanning unit is connected to a second object movable relative to the first. The scanning unit is coupled to the second object by a coupling arrangement which is rigid in the measuring direction, and the scanning unit is guided on an auxiliary guide which functions independently of the guidance for the second object. The coupling arrangement includes a pivot joint with two degrees of rotational freedom along axes perpendicular to the measuring direction for compensation of direction errors, and a linear guide having two degrees of translatory freedom oriented perpendicularly to the measuring direction for correcting for non-parallelism between the auxiliary guide of the scanning unit and the guide of the second object.

Abstract: An incremental length or angle measuring instrument includes a scale having a line grid and a plurality of reference marks. A scanning unit is provided with a plurality of photosensors to scan both the line grid and the reference marks. A reference mark selecting arrangement is described which includes a light source and a photosensor. This selecting arrangement acts to select a subset of the reference marks from the total number of reference marks and to bring only this selected subset of reference marks into operation. This selection takes place through the allocation of a light source or a reflecting element to each of the selected reference marks. The scanning unit operates to generate two square wave scanning signals, a reference signal in response to the reference marks and a selection signal in response to the presence or absence of the light source or the reflecting element associated with the selected reference marks.

Abstract: A precision measuring apparatus (10, 10') includes a measuring scale (12, 12'), a scanning unit (15, 15') for scanning the scale (12, 12'), and a housing (11, 11') for supporting the scale (12, 12') and the scanning unit (15, 15'). The scanning unit (15, 15') rides on guide surfaces (16, 16', 17, 18) at least some of which are defined by flexible bands (19, 20, 28') that are loosely carried by grooves (21, 22, 29') defined by the walls of the housing (11, 11'). The bands (19, 20, 28') provide a relatively straight and smooth guiding arrangement for the scanning unit (15, 15') and they are preferably made of wear-resistant material such as steel. When the housing (11') is comprised of a plurality of housing sections (31'), the bands (19, 20, 28') are made in one piece and bridge the gap between the housing sections (31' ) without interruption.

Abstract: A method and circuit for operating an incandescent lamp are disclosed in which the operating voltage applied to the lamp alternates in a regular and abrupt manner between forward and reverse polarities. The magnitude of the voltage is substantially the same for the two polarities and, therefore, the luminosity of the lamp is substantially constant. However, lamp life is increased as compared to standard DC operation since the alternating polarity of the operating voltage reduces the rate at which the lamp fails due to lamp filament breakage.

Abstract: A lamp support apparatus is disclosed for mounting an incandescent lamp to an electro-optical measuring device mountable on a machine tool. This apparatus includes a spring element for resiliently mounting the lamp to the measuring device and a damping element for damping the oscillations of the lamp. The spring element and the damping element cooperate to protect the lamp from damaging oscillations such as are often encountered in a machine tool environment.

Abstract: An incremental photoelectric measuring device is described including a measuring scale having a line grid and a scanning plate having a line grid, wherein the grid spacings of the two line grids are unequal such that one is an integral multiple of the other. Preferably the scale is provided with the coarser, less expensive to manufacture, line grid and the scanning plate is provided with the finer line grid. In this case the resolution of the measuring device is governed by the fine line grid of the scanning plate which can readily be changed to alter the resolution of the device. Two preferred separations between the scale and the scanning plate are described, which separations provide refraction doubling of the coarser line grid and enhanced spatial precision, respectively.

Abstract: A guiding apparatus for guiding and positioning a scanning unit in a longitudinal measuring device is disclosed wherein the measuring device includes a measuring scale, a driving unit for connecting the device to an object whose position is to be measured, and first and second guide surfaces for guiding the scanning unit along the scale. In the preferred embodiment the guiding apparatus comprises a flexible coupling rod or wire which connects the scanning unit to the driving unit in a flexible manner while maintaining a constant spacing therebetween and first and second springs which bias the scanning unit into contact with the first and second guide surfaces, respectively. Improved guiding and positioning are obtained by separating the coupling function from the guiding function and by using separate springs to bias the scanning unit against the two guide surfaces.

Abstract: A scanning unit for a measuring instrument including a measuring scale is pivotably mounted to a mounting member by a strip of material which forms a solid hinge which permits the scanning unit to pivot with respect to the mounting member about an axis substantially perpendicular to the scale and maintains a substantially fixed spacing between the scanning unit and the scale.

Abstract: In a measuring instrument for measuring or adjusting the relative position of two objects, including a measuring scale, a movably mounted sensor housing unit and an elongated hollow body which is resistant to bending and encloses the measuring scale and the movably mounted sensor housing unit to protect them from environmental influences, at least one ball joint for fastening the hollow body to one of the objects to be measured. According to one of the embodiments, two spheres are positioned at a fastening means at one end of the hollow body and a single, centrally-located ball joint is provided at a fastening means at the other end.

Abstract: An apparatus for compensating for errors in a longitudinal or angular measuring device includes one or more adjustment members arranged to contact the measuring scale of the measuring device and to deflect the scale out of the graduation plane. The deflection of the scale is used to alter the indicated position as measured by the measuring device in order to accomplish the desired correction.

Abstract: A top illumination photoelectric measuring installation to determine the relative positions of two objects is disclosed which includes an optical reflection grid scale and a transmission grid sensor plate laterally with respect to each other and photoelectric elements to receive light reflected from the scale. In this installation, the photoelectric elements are arranged to accomplish a vignetting of the photo-sensitive surface of the photoelectric elements whenever the operating distance between the scale and the sensor plate is such that further movement of the scale and the sensor plate toward one another would produce a photo current greater than that which can be tolerated by the amplifier connected to the photo elements and provided that the admissable range of tolerance is not exceeded. Such an arrangement permits a greater range of operating distances between the sensor plate and the scale than could be achieved under a normal operating arrangement.

Abstract: A displacement measuring system for measuring relative displacements between two members. The second member is free to move relative to the first member along a main guide. The first member has a scale element which tracks the main guide. The second member is coupled to a scanner which moves along its own guide (which may be constituted by the scale element itself) scanning the scale element to provide a measure of the relative displacement. The coupling is flexible in directions at right angles to the direction of relative displacement in order to compensate for tracking errors between the main guide and the scale.An embodiment in which the scale is located off the neutral axis of the scale element the coupling is flexible in a first plane on the level of the neutral axis and in a second plane which includes the longitudinal central axis of the scale and is at right angles to the first plane.

Abstract: An apparatus for maintaining a positioning force on movable parts within a guide means, such as a scanning carriage mounted within a hollow body in an incremental measuring system. The positioning apparatus includes a leaf spring for mounting a pressure roller wherein the leaf spring is provided with at least one slot and the roller-mounting end of the leaf spring is forked. The pressure roller is thereby adjustable so that a rolling surface of the pressure roller remains in parallel alignment with a surface of the guide means.

Abstract: An encapsulated measuring apparatus including a hollow body provided with a longitudinal aperture, a measuring scale and a scanning assembly positioned within the hollow body, connecting means for attaching the scanning assembly to a mounting, and sealing means for the aperture extending from walls of the hollow body and positioned so that the surfaces of the sealing means which contact the connecting means are lower than inner surfaces of the hollow body whereby penetrating liquids flow freely from the hollow body.

Abstract: An incremental measuring instrument having a series of fixed reference marks along one edge of the grid scale is disclosed in which a series of movable magnets are located along the opposite edge of the grid scale so that a magnet may be associated with each reference mark which is needed for control purposes in the particular application in which the system is being used. The magnets are movably mounted so that reference marks not needed for control purposes in any specific application do not have magnets associated with them. An electric switch, preferably a magnetically actuated Reed switch, is also provided in the system's sensor head. Electrical impulses generated by the magnets and the switch are transmitted to an electronic comparator along with electric impulses generated when the sensor head passes over the reference marks.

Abstract: A photoelectric incremental longitudinal measuring instrument is disclosed in which a measuring graduation and a displaceable photoelectric sensor housing unit are enclosed in an elongated hollow body resistant to bending to screen the measuring graduation and the sensor unit from environmental influences. The hollow body is fastened to one of the two objects to be measured with the instrument by fastening means having an articulated design, preferably, a pair of legs formed at an angle to one another having a weak place in the form of a groove in the apex area of the legs. Such an articulated design virtually eliminates the presence of compulsive forces between the hollow body and the object to which it is attached via the fastening means.