Abstract:
A dust-disposal mechanism applied to a machine tool implements a dust-extraction device to efficiently remove cutting dust in a cutting area of the machine tool and prevent cutting dust from floating around in the air.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to machine tools, and more particularly, to a dust-disposal mechanism applied to a machine tool for preventing cutting dust from floating around in the air. 
         [0003]    2. Description of Related Art 
         [0004]    It is known that some materials, such as graphite, wood, composite materials, ceramics and so on, when being machined by a machine tool, tend to generate considerable quantities of cutting dust that is of very fine and very rigid particles. If the machine tool is not equipped with a competent dust-disposal mechanism, such cutting dust can intrude into the machine tool and may damage machine parts or break circuits in the machine tool. 
         [0005]    One conventional dust-proof approach refers to employing a round water curtain that surrounds the cutting area of the machine tool so that cutting dust of the machine tool can be enclosed by the water curtain from escaping outward and distributing over the air. Then the water flowing from the water curtain and containing the cutting dust is collected, filtered and reused. The conventional dust-proof approach however has some defects. 
         [0006]    First, if the water flow is not properly controlled, it may be too strong and damage the workpiece. 
         [0007]    Second, the cutting dust will deposit in the water tank and is difficult to clean. 
         [0008]    Third, this conventional dust-proof approach is inapplicable when the workpiece must be kept dry (such as graphite parts used in semi-conductor manufacturing process). 
         [0009]    An alternative dust-proof solution is dry dust collection. As shown in  FIG. 1 , a dust-collection pipe  80  is provided beside and moves simultaneously with the spindle of the machine tool. Cutting dust of the workpiece machined by the machine tool thus is collected by the dust-collection pipe  80  and is then filtered in a filtering system. Nevertheless, such dry dust collection suffers from some drawbacks. 
         [0010]    Because the dust-collection pipe can not touch the workpiece neither can it causes any obstruction to the automatic tool change process of the machine tool, the dust-collection pipe and its air inlet must remain distant from the spindle and cutting point, resulting in limited dust collecting effect. 
         [0011]    Second, when a long cutting tool is used, the air inlet of the dust-collection pipe is even further from the cutting point, causing the dust collecting effect further inferior. 
         [0012]    Third, since the cutting area is an open space while air flows faster at a location near the air inlet and flows slower at a location far from the air inlet, the cutting dust far from the air inlet can less or can even not be effectively collected and may then distribute over the open space. 
         [0013]    One more conventional dust-proof solution is to use a dust-collection chamber. As can be seen in  FIG. 2 , a dust-collection chamber  81  is installed in the cutting area of a machine tool. The dust-collection chamber  81  has an opening  82  so that a workpiece to be cut can be placed into the dust-collection chamber  81  while a dust-collection pipe  83  is installed on a wall of the dust-collection chamber. Such dust-collection chamber is yet disadvantageous by some reasons. 
         [0014]    First, the opening allows cutting dust of the workpiece to escape therefrom and distribute over the air. 
         [0015]    Second, since air flows faster at a location near the air inlet and flows slower at a location far from the air inlet, the cutting dust far from the air inlet can be less or even not collected, resulting in inferior dust collecting effect. 
         [0016]    Third, when the workpiece is so high that a cutting point thereof is higher than the air inlet, the cutting dust tends to escape from the opening, causing the dust collecting effect incompetent. 
       SUMMARY OF THE INVENTION 
       [0017]    One primary objective of the present invention is to provide a dust-disposal mechanism for a machine tool. The dust-disposal mechanism serves to collect cutting dust in a cutting area of the machine tool and implements a dust-extraction device to efficiently remove the cutting dust from the cutting area, thereby preventing the cutting dust from escaping from the dust-disposal mechanism. 
         [0018]    To achieve the objective of the present invention, the dust-disposal mechanism comprises: 
         [0019]    a dust-collection cover assembled to the machine tool, wherein the dust-collection cover comprises an air-filling structure located above the dust-collection cover and an air-extracting structure located below the dust-collection cover; 
         [0020]    a dust-block board, formed with a spindle hole for allowing a spindle of the machine tool to pass therethrough, wherein the spindle hole is a lengthwise spindle hole; 
         [0021]    a shielding member, settled against an upper edge of the dust-block cover; and 
         [0022]    a dust-collection chamber, settled around a cutting area of the machine tool. 
         [0023]    The air-extracting structure located below the dust-collection cover is a dust-extraction device that is connected with the dust-collection chamber for extracting cutting dust from the cutting area. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The invention as well as a preferred mode of use, further objectives and advantages thereof will be best understood by reference to the following detailed description of illustrative embodiments when read in conjunction with the accompanying drawings, wherein: 
           [0025]      FIG. 1  is a schematic drawing illustrating a device based on a conventional dry dust collection solution; 
           [0026]      FIG. 2  is a schematic drawing illustrating a device based on a conventional dust-collection chamber solution; 
           [0027]      FIG. 3  is a schematic drawing showing the configuration of a dust-block board of the present invention; 
           [0028]      FIG. 4  is a schematic drawing showing the configuration of a dust-disposal mechanism of the present invention; 
           [0029]      FIG. 5  is a cross-sectional view of the dust-disposal mechanism taken along Line  5 - 5  of  FIG. 4  showing paths of air flow thereabout; 
           [0030]      FIG. 6  is another cross-sectional view of the dust-disposal mechanism taken along Line  5 - 5  of  FIG. 4  showing a shielding member added and paths of air flow thereabout; 
           [0031]      FIG. 7  is a schematic drawing showing the dust-disposal mechanism wherein a sliding door of the dust-block cover is closed; 
           [0032]      FIG. 8  is a schematic drawing showing the dust-disposal mechanism wherein the sliding door of the dust-block cover is opened; 
           [0033]      FIG. 9  is a schematic drawing showing the dust-disposal mechanism of the present invention applied to a machine tool having a shiftable spindle; 
           [0034]      FIG. 10  is an enlarged view of the circle at the right part of  FIG. 5 ; and 
           [0035]      FIG. 11  is an enlarged view of the circle at the left part of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0036]    While a preferred embodiment is provided herein for illustrating the concept of the present invention as described above, it is to be understood that the components in these drawings are made for better explanation and need not to be made in scale. Moreover, in the following description, resemble components are indicated by the same numerals. 
         [0037]    Please refer to  FIGS. 3 through 5  for a dust-disposal mechanism according to the present invention. The dust-disposal mechanism comprises a dust-collection cover  3  assembled to a machine tool  1 . The dust-collection cover  3  is equipped with an air-filling structure located above the dust-collection cover  3  and an air-extracting structure located below the dust-collection cover  3 . The dust-collection cover  3  further comprises a dust-block board  10  formed with a spindle hole  101  for allowing a spindle  21  of the machine tool  1  to freely pass therethrough, wherein the spindle hole  101  is a lengthwise spindle hole. The dust-block board  10  is fixed to the machine tool  1  and there is a dust-block cover  11  immovably attached onto a top of the dust-block board  10  for encircling the spindle hole  101  so as to prevent cutting dust from escaping outward through the spindle hole  101 . An outer shield  12  including a shielding member  121  and at least two lateral walls  122  has the shielding member  121  settled upon an upper edge of the dust-block cover  11  with a ventilation gap  111  provided therebetween for ventilation while the two lateral walls  122  are connected with the shielding member  121 . The air-filling structure located above the dust-collection cover  3  refers to the ventilation gap  111  provided between the upper edge of the dust-block cover  11  and the bottom of the shielding member  121 . A dust-collection chamber  13  is settled around a cutting area of a machine tool  1  and below the dust-block board  10 . The dust-collection chamber  13  has an upward opening  131 . The air-extracting structure located below the dust-collection cover  3  is a dust-extraction device  132  that is connected with the dust-collection chamber  13  for extracting cutting dust from the cutting area. The dust-collection chamber  13  further has a front-opened board  133  to be opened for facilitating calibration of the origin of the workpiece. 
         [0038]    Referring to  FIGS. 5 ,  6 ,  10  and  11 , the dust-extraction device  132  draws air into the dust-block cover  11  through the ventilation gap  111  at the upper edge of the dust-block cover  11 . As there is no direct air-communicable channel except the ventilation gap  111  between the dust-extraction device  132  and the exterior of the dust-block cover  11 , according to Bernoulli&#39;s Equation, which states that, for an air flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid&#39;s potential energy, pressure in the dust-collection chamber  13  remains lower than pressure of the exterior and thus external air keeps running inward the dust-block cover  11 , along paths as shown clearly by the arrows in  FIG. 5 . This phenomenon can efficiently prevent dust from escaping out and facilitate collect dust to the dust-extraction device  132  for later removal and thus the subject matter of the present intention presents a significantly improved dust collecting effect. Even if the dust-block cover  11  and the shielding member  121  are closely combined, namely no ventilation gap  111 , through tiny gaps between the shielding member  121  and an extendable covering sheet  123  covering the shielding member  121 , air can be also drawn toward the dust-extraction device  132  so that the excellent dust collecting effect can be still achieved according to according to Bernoulli&#39;s Equation. 
         [0039]    The dust-extraction device  132  is installed at an inner lateral wall of the dust-collection chamber  13  receiving therein a dust-collection machine. The dust-collection machine may be a vacuum device or a draining device. In a case where the vacuum device is a the dust-extraction machine, the dust-extraction device  132  serves to extract the cutting dust in the dust-collection chamber  13 , while in a case where the draining device is a the dust-displacement machine, a water curtain as described in the paragraph of the prior arts is implemented so that water in the dust-collection chamber  13  and dust in the water can be drained through the dust-extraction device  132 . 
         [0040]    Referring to  FIGS. 4 and 9 , the shielding member  121  of the outer shield  12  has one side fixed to an immovable part of the machine tool  1  while the lateral walls  122  of the outer shield  12  each has one side fixed to an immovable part of the machine tool  1 , wherein lower edges of the lateral walls  122  of the outer shield  12  are connected with the shielding member  121 . At least one said extendable covering sheet  123  covers the shielding member  121  of the outer shield  12  and the extendable covering sheet  123  is expandable and slidable along the shielding member  121 . In the present embodiment, two said extendable covering sheets  123  are implemented. The outer shield  12  encloses an inner shield  14  that is settled between the two extendable covering sheets  123 . The inner shield  14  has two sides thereof fixedly connected with the extendable covering sheets  123  and another side connected with a sliding guide  2  that is capable of freely sliding horizontally. When the sliding guide  2  drives the inner shield  14  to move, the extendable covering sheets  123  moves accordingly by expanding or retracting so as to hinder cutting dust in the dust-block cover  11  from coming upward and damaging mechanical components of the machine tool  1 . 
         [0041]    Referring to  FIGS. 7 and 9 , a sliding door  116  is provided at an opening  112  of the dust-block cover  11 . The sliding door  116  is slidable along upper and lower edges of the dust-block cover  11 . A power cylinder  117  settled at the top of the dust-block cover  11  has a driving shaft  118  connected with the sliding door  116 . When the power cylinder  117  is powered, the driving shaft  118  is moved to drive the sliding door  116  to slide, and thus make the opening  112  open or close. When the sliding door  116  slides away from the opening  112 , a tool-changing process can be conducted to the spindle  21  for changing the tool thereon. 
         [0042]    The present invention has been described with reference to the preferred embodiment and it is understood that the embodiment is not intended to limit the scope of the present invention. Moreover, as the contents disclosed herein should be readily understood and can be implemented by a person skilled in the art, all equivalent changes or modifications which do not depart from the concept of the present invention should be encompassed by the appended claims.