Altimeters for Linear Measurements
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LINEAR AND ANGULAR MEASUREMENTS ALTIMETERS FOR LINEAR MEASUREMENTS
M. I. Etingof
UDC 620.1.08.621.758
The metrological capabilities of modern Vernier height gages and altimeters are analyzed, and the field in which they may be efficiently employed is considered. The construction of modern altimeters is set forth in detail. Keywords: vernier height gage, altimeter, converter.
Vernier height gages are intended for marking-off processes on plates and measurements of the height of parts that have been measured out on plates. A mechanical vernier height gage with a graduated scale reading and vernier reading was the first type of altimeter to be developed and produced. Vernier height gages are produced with measurement ranges from 0 to 200, 300, 600, and 1000 mm [1]. The least graduations of the vernier are 0.05 and 0.1 mm. Electronic vernier height gages with digital read-out (similar to an electronic vernier caliper) began to be produced with the appearance of incremental capacitance transducers, and this substantially increased the ease of measurement and the marking-off process. In an electronic vernier height gage where the digital readout is in steps of 0.01 mm, the limit of the permissible error in measurements up to 600 mm amounts to 0.05 mm, and for measurements up to 1000 mm, 0.1 mm [2]. Simultaneous with the appearance of optoelectronic incremental transducers with large ranges of measurement, production of more complex and more precise single-coordinate (along the vertical axis) altimeters was organized. There are also two-coordinate models. An altimeter consists of a rigid molded cast-iron housing mounted on a cast-iron base provided with three fitted points of control and situated on a concrete plate. A carriage with a rigid measurement hard-alloy tip travels in the housing on ball tracks without any backlash. The fixed glass scale of the optoelectronic incremental transducer is also situated there, and a readout device, the electronic block of the transducer, and digital display are situated on the mobile carriage. The carriage travels manually by means of a handwheel. Motorized altimeters are also being produced today. Altimeters are designed for absolute and relative measurements of the dimensions of parts. The “zero” may be set at any point of the measurement range by depressing the zero key on the electronic block. Nozzles through which compressed air from a built-in compressor is fed are present at the points of control for ease of movement of the altimeter along the plate and to protect it from scratching and wear. An air cushion is formed between the plate and the base. Feeding of air is halted when measurements are being taken. The deviation from perpendicularity of the supporting plane of the base and of the line along which the carriage travels amounts to 5–10 μm. The entire electronics module and the compressor of the altimeter are powered from storage cells, making it an independent device that is easy to use under shop conditions. Through the use of altimeters, it is possible to measure t
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