JP2006192559A - Abrasive grains blasting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abrasive grains blasting device to work with air pressure, free of stagnation of abrasive grains or the device being clogged therewith and capable of blasting a proper quantity of abrasive grains continuously at all times. <P>SOLUTION: The abrasive grains blasting device is composed of a reservoir tank having an eject port for abrasive grains, a conduit passage for compressed air, a grain supply controlling means installed at the eject port of the tank, an acceleration chamber whereto the downstream outlets of the supply controlling means and the conduit passage for compressed air are connected, and a blasting nozzle connected with the downstream of the acceleration chamber. The acceleration chamber consists in a conical cylinder whose inner diameter lessens gradually toward the downstream. The controlling means works in controlling the rotation of a valve to allow the grains to fall naturally by opening and closing of the eject port and a screw conveyor able to make forced ejection of the grains through the eject port. The tank may be equipped in the lower part with a gradient for the flow of abrasive grains being directed to the eject port or a device to apply vibrations or impacts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a blasting machine used for surface finishing of a workpiece and the like, and relates to an abrasive grain firing device using air pressure.

  As an abrasive spraying device, one utilizing an impeller disclosed in Patent Documents 1 and 2 according to the applicant's application is known. Patent Document 1 discloses a configuration in which a flexible extension tube is connected to a terminal spray nozzle, and an arbitrary place corresponding to the length of the extension tube and an arbitrary one corresponding to the flexibility thereof are disclosed. Work at an angle.

  On the other hand, in Patent Literature 2, as in Patent Literature 1, there is an apparatus in which an angle adjusting pulley is provided in the middle of the abrasive grain injection device provided with an extension tube, and the angle adjusting pulley is constituted by an impeller. With this configuration, it is possible to accelerate the abrasive grains passing through the refractive conveyance path with this configuration, and the workability related to polishing is not impaired.

Japanese Patent Laid-Open No. 11-347945 JP 2004-181578 A

  All of the above conventional injection devices inject abrasive grains using an impeller, but the abrasive grains are being reduced in diameter to give a more precise finish. In the case of a complicated shape, it is necessary to fire a smaller amount of abrasive grains than the impeller. Moreover, it is preferable to blow away the abrasive grains accumulated in the concave portions as needed so that the abrasive grains do not stay in the concave portions of the workpiece.

  From such a viewpoint, there is an abrasive blasting machine using air pressure as shown in FIG. This blasting machine comprises an abrasive grain storage tank 20 and mainly three pneumatic tubes 21, 22, and 23. Among these, the longest pneumatic tube denoted by reference numeral 21 is an injection tube, and a small hole 24 opened near the inner bottom of the storage tank 20 is provided in the middle of the tube. It takes in and fires by air pressure. In addition, the spray tube 21 may be formed of a flexible tube so that the spray angle of the abrasive grains can be changed. Of the other pneumatic tubes, the one denoted by reference numeral 22 is for filling the lower end to the vicinity of the bottom of the storage tank 20 and stirring the abrasive grains in the storage tank 20 by the air pressure emitted from the opening at the lower end. The attached one is such that the lower end is positioned above the abrasive storage surface of the storage tank 20 and pushes down the abrasive storage surface by the air pressure emitted from the lower end opening, and is small in diameter by both pneumatic tubes 22 and 23. Therefore, the abrasive particles having low fluidity are efficiently guided to the small holes 24 of the spray tube 21.

  With the abrasive blasting machine exemplified here, a relatively small amount of abrasive grains can be fired compared to the impeller-type abrasive grain jetting device, and the air pressure emitted from the jetting tube 21 together with the abrasive grains allows the workpiece to be ejected. Abrasive grains accumulated in the recess can be removed.

  However, in this configuration, since the supply mode of the abrasive grains to the injection tube 21 is through the small holes 24, only a very small amount corresponding to the diameter of the small holes 24 can be supplied to the injection tube 21, and as a result It was difficult to spray a large amount of abrasive grains continuously. In addition, there is a high possibility that abrasive grains are clogged in the small holes 24, and there is no denying the problem that the working efficiency deteriorates. In other words, this conventional apparatus is suitable for firing a small amount of abrasive grains having a large specific gravity and a high polishing ability, but in order to perform more precise polishing, a large amount of abrasive grains having a small specific gravity and a low polishing ability are fired. Not suitable for use.

  The present invention has been made in order to solve the above-described problems, and the object of the present invention is to ensure that there is no stagnation or clogging of abrasive grains in the apparatus, and that an appropriate amount of abrasive grains can always be continuously fired. It is providing the abrasive grain launching apparatus using the. In addition, in this structure, it is also an object to improve the workability and polishing performance related to polishing.

  In order to achieve the above-described object, in the present invention, a storage tank having an abrasive outlet, a compressed air conduction path, abrasive supply control means provided at the storage outlet, the supply control means, Means for forming an abrasive grain firing device from an acceleration chamber to which each downstream outlet of the compressed air conduction path is connected and an injection nozzle connected to the acceleration chamber were used. According to this means, the abrasive grains stored in the storage tank are supplied from the discharge port to the acceleration chamber via the supply control means, accelerated by the compressed air in the acceleration chamber, and ejected from the injection nozzle. The injection nozzle can be formed of a flexible tube as in the prior art.

  The acceleration chamber for the abrasive grains and the compressed air is preferably a conical cylinder whose inner diameter gradually decreases toward the downstream. This is because acceleration by compressed air increases.

  In the present invention, abrasive grains and compressed air are supplied to the acceleration chamber by separate means. However, if the internal pressure of the storage tank remains at the normal pressure at the time of start-up, the pressure difference between the acceleration chamber and the acceleration chamber is instantaneous. A phenomenon occurs in which air flows back into the storage tank and hinders the supply of abrasive grains. After that, it is conceivable that the air flows backward by the amount of the abrasive grains reduced, but as a means to prevent this, a configuration in which the conduction path of the compressed air is branched halfway and the branch port is connected to the storage tank is selectively used. Is preferably employed. By the said means, an acceleration chamber and a storage tank become the same pressure, and it can prevent the backflow of an abrasive grain mentioned above.

  On the other hand, the supply control means has a function of discharging the abrasive grains in the storage tank to the acceleration chamber. Specifically, the supply control means opens and closes the discharge port to allow the abrasive grains to fall naturally, or through the discharge port. It is composed of a screw conveyor that can forcibly discharge grains. As long as the valve can be opened and closed, a known valve such as a butterfly valve or a throttle valve can be used, and an amount of abrasive grains corresponding to the opening degree can be discharged into the acceleration chamber using natural fall. Moreover, if it is a screw conveyor, the quantity of abrasive grain according to the rotation speed of an auger or the size of a spiral tooth can be forcedly discharged to an acceleration chamber.

  In addition, when supplying the abrasive grain of a storage tank to an acceleration chamber by natural fall, in order to supply an abrasive grain with sufficient fluidity | liquidity, it is preferable to comprise a storage tank with the hopper which made the lower cone reverse cone shape. It is also effective to attach a device for applying vibration or impact to the storage tank.

  Furthermore, it is preferable that the abrasive grain replenishing port of the storage tank is constituted by a lid member that forms a mortar-shaped opening on the upper surface of the storage tank and seals the opening from the inside of the storage tank by moving up and down.

  Moreover, in the structure by the above-mentioned means, in order to improve the workability | operativity concerning grinding | polishing, in this invention, it is said that an injection nozzle comprises a flexible tube and the hard handpiece provided in the tip of this tube. Means are also selectively used. According to this means, since the spray angle of the tube can be freely changed using the handpiece as a handle, the polishing operation is easy to perform.

  When the tube is straight, the abrasive grains are uniformly dispersed and sprayed in the tube. However, if the flexible tube is curved, the abrasive grains are displaced in the tube. That is, the abrasive grains flow toward the outside where the arc diameter of the curved curve is large in the tube. In order to control the spraying form of the abrasive grains by utilizing this principle, the present invention selectively employs a means of providing a hand piece so as to hold the tip of the tube in a curved manner. According to the means, by injecting the abrasive grains obliquely with respect to the work surface in a state where the curved portion of the tube is positioned along the work surface, the abrasive grains are injected from the lower side of the tube tip, Compressed air is ejected from above so as to press the abrasive grains against the workpiece.

  Further, in the present invention, means for cutting the tip injection port of the tube obliquely is adopted. According to this means, it is easy to visually recognize the angle and position of the injection port and the injection state of the abrasive grains by using the cut surface upward.

  As described above, according to the present invention, the conduction path between the storage tank and the compressed air is separated, and the abrasive grains are accelerated in the acceleration chamber via the supply control means, so that the conventional abrasive blasting machine using air pressure is used. In comparison, a large amount of abrasive grains can be fired continuously. In addition, in the case where an on-off valve is used as the supply control means, the abrasive grains can be supplied to the acceleration chamber using natural fall with a simple configuration. On the other hand, when a screw conveyor is employed, even abrasive grains whose fluidity has decreased with the reduction in diameter can be forcibly stably supplied to the acceleration chamber. Further, by forming the acceleration chamber in a conical shape, the abrasive grains can be efficiently accelerated toward the injection nozzle. Further, in the case where the hand nozzle is provided at the tip of the flexible tube as the spray nozzle, the polishing workability can be improved while facilitating the adjustment of the spray angle. Furthermore, by providing a handpiece so as to hold the tip of the tube in a curved state, it is possible to eject two layers of abrasive grains and compressed air. And when it injects so that an abrasive grain may become a lower side, while an abrasive grain is injected by increasing the ejection density, polishing performance improves by the induction | guidance | derivation effect | action of the ejection direction by compressed air, and the pressing action with respect to a workpiece | work. Furthermore, since the compressed air also gives a sliding effect of the abrasive grains on the workpiece surface, it leads to an improvement in the finishing mirror surface degree of the workpiece surface.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an abrasive grain firing apparatus according to a first embodiment of the present invention. In the figure, 1 is a hopper-shaped storage tank having an inverted conical portion having a flow gradient at the bottom, and 2 is a storage tank. 1 is an on-off valve as supply control means for abrasive grains connected to the lower opening of 1, 3 is a compressed air conducting pipe, 4 is an abrasive chamber and compressed air acceleration chamber to which the on-off valve 2 and the outlet of the conducting pipe 3 are connected, Reference numeral 5 denotes an injection nozzle connected to the acceleration chamber.

  In this embodiment, a vibrator 6 is attached to the storage tank 1, and by imparting fluidity to the abrasive grains by the vibration, it is possible to prevent the abrasive grains from staying in the storage tank 1 and being clogged by the on-off valve 2. Yes. The on-off valve 2 is a butterfly valve that pivotally supports a plate valve having a shape capable of closing the lower opening of the storage tank 1. The opening degree is determined by adjusting the angle of the plate valve, and the opening degree is commensurate with the opening degree. A large amount of abrasive grains is supplied from the storage tank 1 to the acceleration chamber 4. Further, the conduction pipe 3 is connected to a compressor or the like (not shown), and a conduction path for compressed air is formed therein. Further, in the case of this embodiment, the branch pipe 3a is branched in the middle, and the branch port 3a is connected to the abrasive grain storage surface. It is located above and is connected to the storage tank 1. With this configuration, the inside of the storage tank 1 and the acceleration chamber 4 have the same pressure, and the air in the acceleration chamber 4 can be prevented from flowing back into the storage tank 1.

  And according to the abrasive grain launching apparatus concerning this first embodiment, while circulating compressed air from the compressor etc. to the conduction pipe 3, and opening the on-off valve 2, the abrasive grains of the storage tank 1 become the acceleration chamber 4. It is accelerated by air pressure inside and is ejected from the injection nozzle 5.

  FIG. 2 shows an abrasive grain firing apparatus according to a second embodiment of the present invention, in which 10 is a storage tank, 11 is a vibrator attached to the storage tank 10, and 12 is a bottom part of the storage tank 10. Screw conveyor that is a supply control device capable of discharging abrasive grains to the outside, 13 is a motor for driving the screw conveyor 12, 14 is a conduction pipe for compressed air, and 15 is discharged through a discharge port 11a provided on the bottom side of the storage tank 10. An acceleration chamber 16 for joining the abrasive grains to be compressed and the compressed air flowing through the conductive pipe 14 is an injection nozzle connected to the acceleration chamber.

  Even in the second embodiment, the structure, functions, and advantages related to the vibrator 11 and the acceleration chamber 15 are the same as those in the first embodiment, but in this embodiment, the abrasive grains in the storage tank 10 are forcibly accelerated by the screw conveyor 12. It is made to discharge to the chamber 15. That is, when the abrasive grains are discharged, if the abrasive grains have a shape and a diameter that allow natural fall, the configuration of the first embodiment is simpler and preferable, but if the abrasive grains have a smaller diameter than in this case, Since there is a case where the discharge function due to natural fall may not be obtained due to deterioration of fluidity, in this embodiment, a forced discharge means using a screw conveyor is employed.

  In this embodiment, when the screw conveyor 12 is driven, an amount of abrasive grains corresponding to the rotational speed of the auger and the size of the teeth is discharged into the acceleration chamber 15 where it is urged by compressed air. The abrasive grains are ejected from the injection nozzle 16 in an accelerated state.

  By the way, in an actual polishing operation, it is necessary to adjust the firing amount and firing speed of the abrasive grains according to the workpiece and the desired finish. In this regard, in the present invention, the firing amount can be adjusted by adjusting the supply amount of abrasive grains from the storage tank to the acceleration chamber by the supply control means. In the embodiment described above, the increase / decrease in the amount of abrasive grains supplied to the acceleration chamber can be adjusted by adjusting the opening degree of the on-off valve 2 or adjusting the rotational speed of the screw conveyor 12, etc. The amount of fire can be adjusted. On the other hand, the firing speed can be adjusted by increasing or decreasing the air pressure of the compressed air. However, this method of adjusting the firing speed is an adjustment method when the supply amount of abrasive grains to the acceleration chamber is constant, and when changing the firing amount of abrasive grains during the polishing operation, depending on the amount It is also necessary to raise and lower the air pressure. In other words, when the air pressure in the acceleration chamber is constant, if the supply amount of abrasive grains to the acceleration chamber is reduced, the firing speed of the abrasive grains increases. On the other hand, if the supply amount of abrasive grains to the acceleration chamber is increased, the abrasive grains are increased. Therefore, if it is desired to maintain the same firing speed as before even after increasing the amount of abrasive grains supplied to the acceleration chamber, it is necessary to increase the air pressure. Such adjustment can be achieved by installing a pressure regulator upstream of the compressed air passage, and the operation of the abrasive supply control means (open / close valve and screw conveyor) (abrasive supply amount). ).

  In addition, since the pressure in the storage tank 10 falls, it is necessary to seal the abrasive grain replenishment port of the storage tank 10, but it is preferable to make it the structure which is easy to replenish an abrasive grain. For this reason, in the second embodiment, as a replenishment structure applicable also to the apparatus of the first embodiment, the upper surface opening 10a of the storage tank 10 is formed in a mortar shape, and the opening 10a is vertically moved by a piston 17 in a triangular section. A means of sealing from the inside of the storage tank 10 by the shape lid 18 is adopted. According to the replenishment structure, the abrasive grains are slid down into the storage tank 10 due to the gradient of the opening 10a by discharging the abrasive grains from a separate abrasive supply device (not shown) to the opening 10a. Easy to do.

  Next, FIG. 3 shows a preferred embodiment of the injection nozzle according to the present invention, and the tip of a flexible tube 30 (hereinafter referred to as a flexible tube 30 in this embodiment) is curved. A handpiece 31 is provided so as to be held in a state of being held. The flexible tube 30 can be made of nylon, flexible resin or metal so that the injection angle can be adjusted, but it is preferable to employ a material that can reduce wear in the tube due to the passage of abrasive grains. . However, the material of the tube 30 is not limited. On the other hand, the hand piece 31 is a hard hand so as to function as a handle for the operator to hold during the polishing operation. For example, metal and plastic materials are applicable.

  In such an injection nozzle, in this embodiment, an arc-shaped through-hole 32 is formed in the handpiece 31 and the flexible tube 30 is inserted into the through-hole 32 so that the tip of the flexible tube 30 is held curved. . Further, the distal end injection port 33 of the flexible tube 30 slightly protruded from the distal end of the handpiece 31 is cut obliquely so that the outer side 35 (lower side in the figure) of the curved portion 34 becomes longer.

  Thus, according to the injection nozzle, the abrasive grains T accelerated and introduced in the tube 30 move straight, and as a result, are shifted to the outer side 35 (the lower side in the figure) of the bending portion 34 to bend the bending portion 34. Is hardly distributed on the inner side 36 (upper side of the figure), and is divided into two layers with compressed air. By directing the injection nozzle toward the workpiece W in this state, the abrasive grains T are injected obliquely at a high density with respect to the workpiece W from the lower side of the tip injection port 33 of the flexible tube 30, thereby improving the polishing performance. Can do. Further, the improvement of the polishing performance can be expected also by an inducing action or a pushing action of the jetting direction (path) by the compressed air jetted from above. Furthermore, in addition to the pressing action, the urging force of the compressed air acts on the abrasive grains so as to slide the work surface, so that the finish mirror finish of the work surface can be improved. Furthermore, in the present embodiment, since the tip injection port 33 of the flexible tube 30 is cut obliquely, the angle of the injection port 33 can be reduced by bringing the injection port 33 close to the polishing location so that the cut surface faces upward. Along with the position, the injection state of the abrasive grains T can be easily seen, and an appropriate polishing operation can be performed.

  In addition, how much the flexible tube 30 is curvedly held by the handpiece 31 is not particularly limited. Further, the shape of the tip of the injection port 33 is not limited, and the present invention includes cutting at an acute angle, an obtuse angle, or even perpendicularly.

Explanatory drawing of the abrasive grain firing apparatus which concerns on 1st embodiment of this invention. Explanatory drawing of the abrasive grain firing apparatus which concerns on 2nd embodiment of this invention. Explanatory drawing which showed embodiment of the injection nozzle which concerns on this invention Abrasive blasting machine using conventional air pressure

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 10 Storage tank 2 On-off valve 3, 14 Compressed air conduction pipes 4, 15 Acceleration chamber 5, 16 Injection nozzle 6, 11 Vibrator 12 Screw conveyor

Claims (9)

A storage tank having an abrasive outlet, a compressed air conduction path, an abrasive supply control means provided at the storage outlet, and a downstream outlet of each of the supply control means and the compressed air conduction path. An abrasive grain firing apparatus comprising: an acceleration chamber connected; and an injection nozzle connected downstream of the acceleration chamber. 2. The abrasive grain firing device according to claim 1, wherein the acceleration chamber is a conical cylindrical body having an inner diameter that gradually decreases toward the downstream. 3. The abrasive grain firing device according to claim 1, wherein the abrasive grain supply control means is a valve capable of spontaneously dropping the abrasive grains by opening and closing the discharge port. The abrasive grain launching apparatus according to claim 1 or 2, wherein the abrasive grain supply control means controls rotation of a screw conveyor capable of forcibly discharging abrasive grains via a discharge port. 5. The abrasive grain firing device according to claim 1, wherein the storage tank is provided with a flow gradient of abrasive grains toward a discharge port at a lower portion thereof. The abrasive grain firing device according to any one of claims 1 to 5, wherein a device for applying vibration or impact is attached to the storage tank. The abrasive spray device according to any one of claims 1 to 6, wherein the spray nozzle includes a flexible tube and a hard handpiece provided at the tip of the tube. The abrasive grain firing device according to claim 7, wherein the handpiece is provided so as to bend and hold the tip of the tube. The abrasive grain firing device according to claim 7 or 8, wherein a tip injection port of the tube is cut obliquely.

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