Automatic tensioning machine

Abstract

The invention discloses an automatic tensioning machine which comprises a high-pressure plunger hydraulic pump, a hydraulic jack, a high-pressure connection oil pipe and a pressure sensor. The automatic tensioning device is characterized in that a tensioning cut-off valve revolving shaft, a return stroke cut-off valve revolving shaft, a tensioning throttling valve revolving shaft and a return stroke throttling valve revolving shaft of the high-pressure plunger hydraulic pump are connected with a cut-off valve stepping motor of a tensioning oil cylinder, a cut-off valve stepping motor of a return stroke oil cylinder, a throttling valve stepping motor of the tensioning oil cylinder and a throttling valve stepping motor of the return stroke oil cylinder respectively through plum coupling devices. The cut-off valve stepping motor of the tensioning oil cylinder, the cut-off valve stepping motor of the return stroke oil cylinder, the throttling valve stepping motor of the tensioning oil cylinder and the throttling valve stepping motor of the return stroke oil cylinder are driven by a stepping motor driver which is controlled by a PLC. The automatic tensioning machine simulates manual operation, effectively improves control precision and working efficiency, saves labor and reduces labor intensity.

Description

technical field [0001] The invention relates to construction engineering equipment, in particular to a prestressed steel bar tensioning machine. Background technique [0002] Prestressed engineering is a part of concrete structures in buildings and bridges. Only with prestressed engineering can we realize various cement products with light structure and strong bearing capacity for long-span concrete bridges across rivers and seas and containment vessels for nuclear power plant reactors. The core process of prestressing engineering is the tensioning of prestressed tendons. Its working principle is briefly described as follows: The hydraulic jack generates a strong pulling force under the action of high-pressure liquid generated by the hydraulic pump and drives the anchor to move. The stress tendons are also driven, and finally the tensile force generated on the prestress tendons is fixed through anchors and acts on the concrete structure, so that the artificial pre-applied co...

AI Technical Summary

Problems solved by technology

[0005] The first manual stretching method has the following disadvantages: low efficiency, error-prone, and inability to record data

Using the second tensioning method has improved compared with the first one, but there are still the following disadvantages: 1. The maximum withstand pressure of the hydraulic solenoid valve is 40Mpa, while the oil pressure commonly used in prestressing engineering exceeds 50Mpa, so that There are oil leakage and failures caused by overload, that is, the reliability is poor; 2. The automatic control implemented by the electromagnetic hydraulic valve is a shut-off type, and there are only two states: fully open or fully closed, and there is no way to implement oil supply. The flow rate that can be achieved manually can be adjusted, so fine adjustment of the oil pressure cannot be performed, and the accuracy of the prestressed tension value cannot be guaranteed

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