Abstract: An optical microscope can be converted by the user quickly with a few movements of the hand so that it can be used as an upright variant or as an inverted variant. The required optical elements are accommodated in components that can be mechanically separated from one another and variously combined. The optical system is calculated in such a way that an upright microscope with vertical illumination or transmitted illumination or an inverted microscope with vertical illumination or transmitted illumination results when the components are combined in the required manner by interfaces provided for this purpose.

Abstract: A microscope tube comprises a housing (1) having a lower housing part (3) and an upper housing part (2), input optics (9) mounted on the lower housing part (3), which are provided for coupling to an infinite optical path of a microscope, a tube lens (12) mounted in the upper housing part (2), which is arranged on a common optical axis (OA1) with the input optics (9) and combines ray pencils supplied by the input optics (9) in an intermediate image, so that a finite optical path is formed between the tube lens (12) and the intermediate image, and a prism unit (13) mounted in the upper housing part (2) and arranged following the tube lens (12), said prism unit (13) deflecting the further optical path (OA2) by a solid angle of between 65° and 75° and being arranged in the finite optical path such that the intermediate image is viewable without further intermediate imaging by binocular optics (4) mountable on the upper housing part (2), said upper housing part (2) and said lower housing part (3) being mut

Abstract: A microscope with an exchangeable intermediate tube that is inserted between the microscope objective and an ocular eyepiece instead of the tube lens and which is adjustable in a defined manner with respect to its height and has relay or transfer optics with an essentially constant intersection length, comprising, in the observation direction, a first lens group with a long focal length, preferably greater than 10 m, and a second lens group with a short focal length whose common focal length corresponds to the focal length of a standard tube lens, preferably approximately 164 mm, wherein the distance between the first and second lens group is adjustable.

Abstract: A linear guide includes rolling bodies that are inserted into mutually corresponding grooves of mutually guided parts. The guide surfaces for the rolling bodies are partially formed by plane surfaces of rotatable beveled round rods that are positioned in the grooves. The linear guide is constructed as a double guide on both sides with respectively two spaced-apart guide grooves on mutually opposed sides of the mutually guided parts. Because the guide surfaces are partially formed by the plane surfaces of the rotatable beveled round rods, wedge angles between the mutually guided parts are compensated. Manufacturing technical requirements regarding the matching of the distances of the guide grooves to each other are thereby greatly reduced.

Abstract: In a microscope such as for the examination of specimens in specimen vessels, a device for changing objectives is provided. The microscope includes at least a first objective. The device comprises an arrangement for providing an operating control so that the at least first objective can be raised and lowered vertically and is displaceable horizontally vertical to an optical axis of the microscope.

Abstract: A drive system for the conversion of a rotary motion into a linear motion contains a belt drive similar to a block and pulley system, and a system of a rack and pinion that is driven synchronously with the belt drive. The pinion and the rack are adjusted with respect to each other such that the teeth of the pinion engage with relatively large play in the rack. When driving under normal load, the drive takes place without loading of the rack and pinion system by the belt drive, so that the reversal backlash and the play of the rack and pinion system remain without effect on the displacement motion. When an overloading of the moving part and a corresponding stretching of the drive belt occur, the tooth flanks of the pinion and of the rack are supported against each other and in this manner prevent tearing or overloading of the drive belt.

Abstract: A process for the production of thick synthetic resin sheets having a multicolor pattern, involves processing heated thermoplastic chips into a coherent sheet by means of a pair of rolls profiled to a depth of about 0.1-0.5 mm which effect partially differing densification.

Abstract: Process and apparatus for producing a sheet or film exhibiting a colored band of varying color intensity, with an extruder for melting a stream of a thermoplastic synthetic resin and with a slot die tool (e.g.

Abstract: A slot die apparatus for the coextrusion of an endless sheet having a thickness of about 0.1-5 mm with an optionally dyed edge strip made from a narrower, optionally colored, melt stream of a width of about 100-500 mm and from a broader melt stream of a width of about 1,000-3,000 mm of a thermoplastic synthetic resin is provided by means of two parallel-operating extruders and associated melt pumps, with merging of the two melt streams. The apparatus is also provided by flanging together, by means of a flange, two dies at their end faces, these dies having identical cross sections and a corresponding width, comprising a spreader block, deckle, bottom lip, and top lip, and a flow channel made up from these components.

Abstract: A process for the production of patterned tiles from thermoplastic synthetic resins includes the steps of forming a length of crude sheet stock by compressing unicolored and/or differently colored or multicolored particulate material of thermoplastic synthetic resin; cutting off crude sheets from the sheet stock; punching segments out of the crude sheets; combining the segments from at least two crude sheets of differing colors into a panel so that the segments complement one another, and thereafter press-molding the segments to form an intarsia tile with the use of pressure and heat so that the segments are welded together along joints formed therebetween.

Abstract: A process for the continuous manufacture of sheeting from thermoplastic synthetic resins includes the steps of applying thermoplastic synthetic resin, in the form of particles, such as shreds, crumbs, cuttings, pieces, chips, or the like, continuously as a sheet-like layer of raw material to a moving support; passing the raw material layer through a heating zone to thereby preheat the material layer to a temperature approximately in the range from 100.degree. to 140.degree. C.; pressing the preheated material layer continuously over its full area during travel through a treatment zone so that, in a first phase, the raw material layer is compacted and welded under the effect of a pressure of from about 10 to 60 kp/cm.sup.2 and at the same time the material layer is heated to a temperature in the range from about 160.degree. to 220.degree.

Abstract: A process for extruding a film having small variations in thickness by regulating the quantities fed to a worm press and by regulating the extrusion process. Marginal strips and waste products of extruded film are re-processed by returning these materials, slicing them and directly weighing them before being fed to the filling bin of the screw press. In order to regulate the quantities fed to the screw press, the weighed material per unit of time is continually subtracted from a nominal value set by a volume regulator associated with the raw material seeder devices. The filling degree of the screw press is measured as the mass pressure between the screw press and a constant volume pump such that the filling degree is maintained constant during the extrusion process.