Trigger position adjustable limit switch

Abstract

The invention relates to a limit switch with an adjustable triggering position and belongs to the technical field of an electric control device. The limit switch comprises a triggering mechanism and a control part, wherein the triggering mechanism comprises a triggering rod arranged on an equipment stroke, a trigger linked with the triggering rod and a digital sensor close to the trigger; the control part comprises a counter, a dial switch and a comparator; an output end of the digital sensor is connected to an input end of the counter; the output ends of the counter and dial switch are connected to the input end of the comparator; a controlled end of the counter is externally connected to the output end of a running controller of the equipment; and the output end of the comparator is externally connected to the input end of the running controller of the equipment. Compared with the existing limit switch, the limit switch provided by the invention has a single fixed triggering position. By manually revising a preset value, an equivalent effect of forming a plurality of continuous adjustable triggering positions is achieved. Especially, with regard to a condition of insufficient equipment stroke, the normal stable triggering of the limit switch can be ensured without on-site adjustment.

Description

technical field [0001] The invention relates to a limit switch and belongs to the technical field of electrical control devices. Background technique [0002] The limit switch is an electrical control device commonly used to detect and control the position of moving equipment (such as oil cylinders, elevators, etc.), and is usually installed at the set position of the equipment's movement stroke (line). When the device moves to this position, a bump fixed on a certain part of the moving device presses the limit switch, so that the contact of the limit switch is triggered (that is, the contact is closed or opened), and then the output signal is controlled The device stops moving. [0003] Existing limit switches have high requirements on the degree of pressing of the bumps, and usually a certain pressing force must be met to trigger the contacts of the limit switch. Therefore, the existing limit switches are generally pressed to a certain position by the bumps (usually a cer...

AI Technical Summary

Problems solved by technology

[0004]In actual use, the movement position of the device will always deviate after a long time of use, so there will be unstable triggering of the limit switch contact caused by insufficient travel of the device, Not even triggered, or the three phenomena of the limit switch being interrupted due to overtravel

Among them, generally only when the limit switch of the equipment overtravel (such as the rotation angle is greater than 75°) is interrupted or the limit switch of the equipment stroke is not triggered (such as the rotation angle is less than 5°), the maintenance workers will go to the site for inspection; The more common situation where the stroke of the equipment is slightly insufficient or skipped causes the triggering of the limit switch to be unstable. Generally, nothing can be done, but sometimes the position of the limit switch is roughly adjusted based on simple observation on site.

However, the unstable triggering of the limit switch is more harmful to the normal movement of the equipment. Its manifestations are as follows: First, it is impossible to accurately know whether the unstable triggering of the limit switch is the over-travel or insufficient stroke of the equipment, so that the equipment cannot be maintained and repaired in time The second is that even if it is judged from experience that the equipment is one of over-travel and insufficient travel, the position of the limit switch can only be roughly adjusted by manually going to the scene according to estimates, which cannot effectively solve the problem of unstable triggering of the limit switch, thereby still It leads to unstable operation of the equipment; third, the existing limit switches are generally fixed on the base by four fixing screws, and it is very troublesome to adjust the position on site, which is easy to delay the operation and production of the equipment

To sum up, there is currently no effective solution for the unstable triggering of the existing limit switch due to insufficient or skipped equipment travel; the current method of going to the site to adjust the position of the limit switch is completely blind, which will not only delay the equipment Running production, once a failure occurs, the electrical control device needs to be replaced as a whole, which is a serious waste

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