Solutions to common mechanical failures in optical microscopes

First, the rough adjustment failure

The fault phenomenon is that when the coarse focus screw is rotated, the lens barrel cannot be lifted and lowered. The simple lifting of the microscope mirror is realized by the gear driven by the strip, and the gear is fixed on the rotating shaft of the coarse adjustment knob, and the rack is fixed on the lens barrel. When the coarse adjustment knob is turned, the gears move the bar to raise and lower the lens barrel. If the lens barrel cannot be lifted or lowered, the gear does not match the rack. A common cause of failure is that the rack sleeve rotates with the coarse adjustment knob, that is, the two stop screws on the rack sleeve do not fix the rack sleeve on the dovetail rail. The repair method is to move the gear to the middle of the notch of the rack sleeve, and the notch of the rack sleeve faces the rack, and then tighten the two stop screws on the end face of the tail rail with a small screwdriver. If it is invalid, it indicates that the rack is seriously worn. It is necessary to remove the lens barrel, screw out the fixing screws above and below the rack, and use the rack upside down because the rack wear mainly occurs in the upper part of the rack. Or cut a piece of metal foil according to the width of the rack, let the metal foil be mounted on the rack, and fix the sheet and the rack to the lens barrel with fixing screws, and insert the lens barrel to debug. If you feel tight, you can change the thickness of the foil until it is suitable. Or purchase new racks from the manufacturer according to the original model specifications.

Second, the lens tube slides on its own

The fault phenomenon is that when the focal length is aligned, the hand releases the quasi-focus spiral, and the mirror will slide down by itself, resulting in inaccurate focal length. In the coarse adjustment structure of the microscope, the elasticity of the gear shaft is generally controlled by the friction between the gear sleeve and the coarse adjustment knob, and the friction between the gear shaft and the gear sleeve is two connected to the gear shaft. A coarse adjustment travel button is obtained by pressing two plastic washers against the end face of the rack sleeve. The tighter the grain rotation or the end face of the rack sleeve, the greater the friction. The reason why the lens barrel slides down by itself is that the friction between the gear shaft and the rack sleeve is reduced due to the wear and tear of the washer, and the friction between the gear shaft and the rack sleeve can not overcome the gravity of the barrel itself. And caused by the generated torque. The repair method is to hold the coarse adjustment knob on each side of both hands, and tighten the coarse adjustment knob in the clockwise direction. If it is not, you need to thicken the gasket. Use a needle-nosed pliers to insert into the eye nut of the end of any coarse adjustment knob, unscrew it, remove the coarse adjustment knob, take out the plastic washer, cut a washer of the same diameter with green paper or thin plastic sheet, and clamp it in the original gasket. Between the coarse adjustment knobs, reinstall it. If it is very laborious to turn the coarse adjustment knob, it means that the gasket is too thick. You should change the thin washer. In short, you can rotate the coarse adjustment or have a certain resistance. The decline is subject to change.

Third, the concentrator can not be positioned or stuck

There are two common types of concentrators: one is a disc or a light bar, and there are round holes of different sizes in the disc. This diaphragm is positioned by the positioning spring under the stage and the ball snapping into the positioning hole of the disc. When the ball is lost or the spring fails, the beam cannot be positioned. The repair method is to replace the balls or springs. Some manufacturers have now changed the positioning method relying on springs and balls to rely on spring pieces to position them. This structure is more firm and less prone to damage. The other is a rainbow-type beam, which consists of twelve arc-shaped thin steel sheets (ie, shading sheets). As long as you move the handle on the sliding weight, you can change the size of the aperture. The common fault is that the small steel column on the shading sheet falls off, causing the handle to be stuck and the aperture to be changed. The repair method is to loosen the two fixing screws on the light bar with a small screwdriver, take out the light shielding film, reinstall the small copper column that has fallen off on the light shielding film, and glue the small copper column with 502 glue to prevent it from falling off again. When installing, be careful that the two small copper posts on each visor are oriented in the opposite direction. Or find a small piece of copper and a small copper wire with a tight aperture on the piece of light to make a small copper column, then put the bottom plate of the light bar (the plate with twelve small holes called the bottom plate) upwards, and put each piece The small copper pillars at the end of the opaque sheet are inserted into the small holes of the bottom plate, and are arranged neatly in a reverse-to-outer direction. Then, the sliding groove on the sliding plate is sequentially placed on the small copper column at the other end of the light shielding plate, and the cover plate is covered, and the three fixing screws can be tightened. If the light shielding piece is broken, the broken light shielding piece is taken out. The column can still be used normally, and two or more pieces should be purchased and replaced by the manufacturer.

Fourth, the tilt joint is too loose

The inclined joint refers to the movable joint where the mirror arm and the mirror column are connected. When using the microscope, the mirror arm is often tilted backward to an angle suitable for observation. After use, the inclined joint may be loosened, so that the mirror arm cannot be tilted at will. The repair method is that the needle-nosed pliers are respectively inserted into the two eye-opening nuts of the inclined joint end face, and rotate clockwise until the arm is tilted moderately. If it is invalid, it may be that the friction washers on both ends of the mirror arm and the mirror column are worn. It is necessary to thicken the washer. Use a needle pin to unscrew the eye nut, take out the rotating shaft, and cut a diameter of the same shape with green paper or thin plastic sheet. Kuitu thickened the original gasket and reassembled it.

Fives. The pins of the mirror are too loose or too tight in the socket

There are two kinds of mirror pin structure: one is to open the slot on the pin, depending on the width of the slot to adjust the pin in the socket. When the pin is too loose in the socket, a slotted screwdriver can be inserted into the slot of the pin. The opening of the slot is increased to make the pin fit tightly within the socket. Conversely, when the pins are too tight, the wire cutters can be used to close the opening in the slot on the pins. The other is to use the tightening screw to adjust the pin in the socket. When the pin is too loose in the socket, use a screwdriver to tighten the captive screw. If the pin is too tight in the socket, when the mirror is turned, the pin is easily broken, and the screw can be loosened with a screwdriver.

It is not very difficult to repair the common faults of the above microscopes. As long as someone dials a little, they can learn. Microscopes fail during use, a common phenomenon, as long as we take it seriously. When repaired in time, the microscope can be kept in a normal state.