On the protective device of the most popular bill

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The protective device of the trial produced bill tearing machine (Part 1)

is 20% lighter than the traditional ultra light aluminum engine in weight. Bill tearing machine is a very important equipment in bill printing, and its use greatly improves the production efficiency and quality of manual bills. However, the early tearing machine was not equipped with a paperless protection device, which caused a lot of inconvenience to production. For example, in the process of tearing pages, the paper of a certain joint was broken. Due to the high running speed of the equipment, it was difficult for the operator to find it, and the machine could not be shut down in time. When it was found, it would take a lot of time to correct the errors, reduce the production efficiency, and even cause quality accidents in serious cases. Therefore, it is necessary to install a set of protective devices

requirements for paper shortage protection device

1 The added protection device shall ensure that the equipment can operate normally when there is paper on the paper support. Once one or several paper supports are short of paper, the equipment will be shut down immediately, and it will not continue to operate when the "run" button is pressed

2. Due to the needs of production, the times of tearing by the page tearing machine are not necessarily the same each time, so it should also be able to control the corresponding paper support separately

3. Since the paper will shake on the paper support when the equipment is running, the detection device should have a certain detection range and stability, and will not stop because of this

this device is designed to turn the paper shortage signal into a shutdown action. In fact, the emergency stop button on the original control circuit of the page tearing machine can meet the above conditions, so we understand the shutdown action as the same function as the emergency stop button, that is, to cut off and remove the production capacity, so that regular enterprises can taste the sweetness. The adjustment pointer opens the main control circuit. Contactors can be used to achieve the above requirements. Now, as long as the paper shortage signal is transformed into the action signal of the contactor, the key is to determine the paper detection device

selection of paper detection device

because it is difficult to contact the paper and the detection device when the equipment is running, we consider using a proximity switch. The photoelectric proximity switch has no mechanical wear and does not produce electric sparks. It is a safe and reliable contactless switch with exchange calculation formula of three vibration parameters: acceleration (a), velocity (V) and displacement (d). It has a long service life. It realizes control by converting the change of light intensity into the change of electrical signal. The detection range and sensitivity can be adjusted, which fully meets the requirements of the above three items

there are several types of photoelectric switches, such as reflection type, reflector reflection type and diffusion reflection type. Due to the short distance between adjacent paper supports (about 30cm), the diffusion reflection photoelectric switch is convenient to install and use. The working principle of the diffusion photoelectric switch is shown in Figure 1

its detection head is equipped with a light emitter and a light receiver. Under normal circumstances, the light receiver cannot receive the light emitted by the light emitter, as shown in Figure 1 (a). When the detected object blocks the light and partially reflects the light back, the light receiver receives the light signal, as shown in Figure 1 (b), and outputs a switch control signal

for the diffuse reflective photoelectric switch, the material, transparency, color difference, surface reflectance, etc. of the detected object will change the detection distance, which can be adjusted appropriately during use

(to be continued)

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