bridge plateDefinition:bridge plateIt is a metal plate with two supporting surfaces. The distance between the centerlines of the supporting surfaces at both ends of the bridge deck is calledSpan, the span is determined based on the length and accuracy requirements of the measured surface. Due to the fact that the bridge deck is an important tool for reflecting the principle of pitch measurement, it directly affects the acquisition of flatness measurement data and the evaluation of error values. The span not only reflects the pitch size of the measured surface, but also determines the division value of the measuring instrument after using the bridge plate, which characterizes the accuracy of the measuring instrument. The division value of the measuring instrument is determined by the bridge span and instrument reading. The instrument reading indicates the angle between the line connecting the two support points of the bridge deck and the horizontal line or optical axis, that is, the height difference between the two points relative to the span length of the bridge deck.

The form of bridge deck: Standards and inspection regulations do not specify the form of bridge deck, so the bridge deck currently used is mostly self-designed and manufactured, with a variety of forms, generally divided into two categories. According to its adjustable span, it can be divided into fixed and adjustable types; According to the shape of its supporting surface, it can be divided into linear and planar types.

There is another type of work surfaceAdjustable bridge deck, can be adjusted by adjusting the screw1Turning around the pivot point three times to adjust the working surface of the bridge deck can simplify the leveling work of the measured part and bring convenience to the measurement.

The selection of bridge deck form should be adapted to the shape of the measured surface. In principle, when measuring the plane, two supporting surfaces are generally used in the same plane, and can be ground on a flat plate to measure its parallelismVWhen shaping, the two supporting surfaces should beVType_ Note that only the two supporting surfaces of the bridge deck are allowed to make contact with the measured surface, otherwise the position of the measuring point and the span of the bridge deck cannot be determined.

The function of the bridge deck is to change the measurement pitch and perform reasonable segmentation. The level and collimator reflector have a fixed length, and the change of pitch and equidistant segmentation are achieved by changing the bridge span, which facilitates measurement.

_Node contact improves detection accuracy. The stability and accuracy of the measurement have been improved by ensuring good contact between the bridge plate measuring instrument and the reflector base at the node with the measuring surface.

_Measuring tool accuracy to avoid surface wear. The bridge plate is used to place a level or reflector base, avoiding destructive wear and loss of original accuracy caused by direct contact between the measuring instrument working surface and the measured surface.