Abstract:
The present invention provides a dust collection unit usable with an electric tool having an electric motor, an end tool driven by the electric motor, and a cover partially covering the end tool and having a residue discharge port. The dust collection unit is detachably communicable with the residue discharge port. The dust collection unit has a main casing, lid means, and a handle. The main casing is configured to accommodate dust and residues therein. The main casing has an opening. The lid means opens and closes the opening. The handle is provided in proximity to the lid means on the main casing.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Technical Field  
         [0002]     The present invention relates to a dust collection unit and an electric tool having the dust collection unit.  
         [0003]     2. Related Art  
         [0004]     Some of electric circular saws for cutting a workpiece such as a wooden piece have a dust collection unit that collects and accommodates chips and residues generated when the workpiece is cut. Japanese Patent Publication 2005-022338 discloses an electric circular saw having a dust collection unit, as shown in  FIG. 1 . The electric circular saw  210  includes a housing  213 , a saw blade  214 , and a base  215 . The housing  213  contains an electric motor (not shown) The saw blade  214  is rotated by the electric motor. The base  215  is coupled to the housing  213  and slides on a workpiece  216  so that the saw blade  214  cuts the workpiece  216 . The electric circular saw  210  has a dust collection unit  201  that is detachable thereto.  
         [0005]     The dust collection unit  201  is provided to collect chips and residues generated when the saw blade  214  cuts the workpiece  216 . The collection unit  201  has a coupling part  203 , a holding part  206 , and a box part  205 . The coupling part  203  has a hollow cylindrical shape. The box part  205  has a plurality of windows  205   a  made by cutting. The box part  205  contains a bag  230 . The bag  230  is made of Japanese paper or a filter member of synthetic fiber. The bag  230  has a mesh that allows only air to pass therethrough.  
         [0006]     The dust collection unit  201  is attached to the electric circular saw  210  when the coupling part  203  is inserted into the dust outlet port  212  that is a hollow cylinder integrally formed in the housing  213 .  
         [0007]     As shown in  FIG. 1 , the saw blade  214  cuts the workpiece  216  when the saw blade  214  is driven by the electric motor. The chips and residues generated during the cutting process move to the dust outlet port  212  by virtue of the inertia of the rotating saw blade  214  and an airflow generated by the rotating saw blade  214 . The chips and residues are then guided together with the air from the coupling part  203  into the bag  230  in the box part  205 .  
         [0008]     After the chips and residues are guided together with air into the bag  230 , only the air passes through the bag  230  and are released into the atmosphere through the windows  205   a  of the bag  230 . The chips are accumulated in the bag  230 . When the bag  230  is filled up with chips, the box part  205  is removed from the holding part  206  by an operator. The bag  230  is then taken out of the box part  205  and is discarded. Hence, the chips and residues are disposed of without being scattered around the electric circular saw  210 .  
         [0009]     To discard the bag  230  filled up with chips, however, the operator must first hold the dust collection unit  201  with one hand, and the electric circular saw  210  with the other hand. The operator then separates the dust collection unit  201  and the electric circular saw  210  from each other, grabs the box part  205  with both hands, and removes the box part  205  from the holding part  206 . This is a cumbersome work for the operator to do.  
         [0010]     To hold the bag  230  filled up with chips with one hand, the operator needs to place the coupling part  203  and holding part  206  temporarily at another place.  
         [0011]     In order to solve the above problems, an object of the present invention is to provide a dust collection unit from which the collected chips and residues can be easily discarded with one hand. Another object of the present invention is to provide an electric tool having such a dust collection unit.  
       SUMMARY OF THE INVENTION  
       [0012]     The present invention provides a dust collection unit usable with an electric tool having an electric motor, an end tool driven by the electric motor, and a cover partially covering the end tool and having a residue discharge port. The dust collection unit is detachably communicable with the residue discharge port. The dust collection unit has a main casing, lid means, and a handle. The main casing is configured to accommodate dust and residues therein. The main casing has an opening. The lid means opens and closes the opening. The handle is provided in proximity to the lid means on the main casing.  
         [0013]     The present invention further provides an electric tool having an electric motor, an end tool driven by the electric motor, a cover partially covering the end tool and having a residue discharge port, a dust collection unit detachably attached to the residue discharge port. The dust collection unit has a main casing, lid means, and a handle. The main casing is configured to accommodate dust and residues therein. The main casing has an opening. The lid means opens and closes the opening. The a handle is provided in proximity to the lid means on the main casing. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The aforementioned aspects and other features of the invention are explained in the following description, taken in connection with the accompanying drawing figures wherein:  
         [0015]      FIG. 1  is a side view of a conventional electric circular saw having a dust-collecting unit;  
         [0016]      FIG. 2  is a side view showing a miter saw according to an embodiment of the present invention;  
         [0017]      FIG. 3  is a side view showing a dust collection unit;  
         [0018]      FIG. 4  is a perspective view showing a part of the dust collection unit;  
         [0019]      FIG. 5  is a plan view showing a structure of a frame member and a base member;  
         [0020]      FIG. 6  is a perspective view showing the dust collection unit with a lid being open;  
         [0021]      FIG. 7  is a view illustrating a way to throw chips and residues away into a garbage bag; and  
         [0022]      FIG. 8  is an exploded view showing another structure of a dust collection unit. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0023]     An embodiment of the present invention will be described, with reference to the accompanying drawings. In the drawings, like elements are identified by the same reference numerals, with duplications of an element in the same figure identified by subscripted reference numerals.  
         [0024]     Referring to  FIG. 2 , a the miter saw  10  includes a table  15 , a housing  13 , and a circular saw blade  14 . The table  15  has a stand  16  to support the housing  13 . The housing  13  is pivotable about a rotary shaft  17  provided at an upper end of the stand  16 . The housing  13  accommodates an electric motor (not shown) to rotate the saw blade  14 . The housing  13  includes a saw cover  21  for covering an upper half of the saw blade  14 . The circular saw blade  14  is pivotably movable together with the housing  13  about the shaft  17  to cut a workpiece W such as a wooden block carried on the table  15 .  
         [0025]     The saw cover  21  has a dust ejection port  12  facing an outer edge of the saw blade  14 . A dust collection unit  1  is detachably attached to the dust ejection port  12  to be in fluid communication with the inside of the saw cover  21 .  
         [0026]     Referring to  FIG. 3 , the dust collection unit  1  includes a main casing  1 A and a lid  6 . The main casing  1 A has a base member  2  and a filter member  5  attached to the base member  2 .  
         [0027]     The base member  2  has a tubular shape having a cylindrical or rectangular cross section along an imaginary tubular axis. The base member  2  is made from a transparent or translucent synthetic resin such as acrylic resin. The base member  2  has two open ends. As shown in  FIG. 6 , one of the two open ends is formed as a dust ejection port  20 . A handle  7  is provided on the outer side surface of the base member  2 . The lid  6  is configured to open and close the dust ejection port  20 .  
         [0028]     The lid  6  is made from a resin and has the same shape as the cross section of the base member  2 . A coupling cylinder  3  is formed integral with the lid  6 . The coupling cylinder  3  has an inside diameter which is greater than the outside diameter of the dust ejection port  12 . Accordingly, the coupling cylinder  3  is removably fitted to the dust ejection port  12 , as shown in  FIG. 2 . When the dust ejection port  12  is connected with the coupling cylinder  3 , the dust collection unit  1  is in fluid communication with the inside of the saw cover  21  through the coupling cylinder  3 .  
         [0029]     The lid  6  is pivotably coupled to the one open end  20  of the main casing  1 A through a hinge  8  in order to open and close the dust ejection port  20  of the main casing  1 A. The hinge  8  is provided on the opposite side to the handle  7 . A torsion coil spring (not shown) is wound around the hinge  8  to urge the lid  6  to rotate in a direction away from the dust ejection port  20 .  
         [0030]     The filter member  5  is made of a flexible bag with an open end being fold back. The filter member  5  is removably attached to the other open end  2 A of the base member  2 . In this embodiment, the other open end  2 A is open in a direction slanted from the imaginary tubular axis. The filter member  5  is made from Japanese paper, fabrics, and synthetic fibers such as any material having a mesh that allows only air to pass.  
         [0031]     The filter member  5  contains a wire frame  9  to maintain the filter member  5  in a developed shape. As shown in  FIGS. 3 and 4 , the wire frame  9  has a circular portion  9 A and a linear portion  9 B.  
         [0032]     The linear portion  9 B is inserted inside of the filter member  5  and the circular portion  9 A is accommodated in the folded open end of the filter member  5 . The wire frame  9  with the filter member  5  is then fitted in a groove  2 A formed around the outer surface of the other open end of the base member  2  so that the filter member  5  is attached and fixed to the base member  2  by means of the wire frame  9 . At this time, as shown in  FIG. 5 , one end  9   a  of the circular portion  9 A is bent in the shape of L and fitted in a small groove  2   a  extending from the groove  2 A at a right angel through the filter member  5 . A proximal end  9   b  of the linear portion  9 B is bent substantially at a right angle with respect to the circular portion  9 A and fitted in a groove  2   b  extending from the groove  2 A to the other open end of the base member  2 .  
         [0033]     The linear portion  9 B has a length in a manner that the other end  9   c  thereof nearly reaches the bottom of the filter member  5  (to the right in  FIG. 3 ). The other end  9   c  is looped to avoid any damage to the filter member  5 . As shown in  FIG. 4 , after the filter member  5  is attached to the base member  2  by the wire frame  9  which has been fitted in the groove  2 A and the small grooves  2   a  and  2   b , the handle  7  is attached to the base member  2  by screws (not shown) so as to sandwich the ends  9   a  and  9   b  with the base member  2 . Thus, the wire frame  9  is readily secured to the base member  2 .  
         [0034]     Referring to  FIG. 3 , a drive mechanism  4  is provided near the handle  7  on the outer surface of the base member  2 . The drive mechanism  4  operates the lid  6  to open and close the dust ejection port  20 . The drive mechanism  4  has an engaging element  18  that is rotatable around a shaft  22  provided on the outer surface of the base member  2 . In other words, the drive mechanism  4  closes the dust ejection port  20  with the lid  6 , as shown in  FIG. 3 , when the engaging element  18  is engaged with a peripheral edge of the lid  6 . The drive mechanism  4  releases the lid  6  and opens the dust ejection port  20 , when the engaging element  18  is disengaged with the peripheral edge of the lid  6 . A return spring  19  is provided between the engaging element  18  and the base member  2  so as to bias the engaging element  18  to maintain the engaged condition with the peripheral edge of the lid  6 .  
         [0035]     As described above, the lid  6 , the engaging element  18 , and the return spring  19  constitute the drive mechanism  4  for opening and closing the dust ejection port  20 . The engaging element  18  and the return spring  19  are located in the vicinity of the handle  7 . And an operator can manipulate this mechanism with one hand.  
         [0036]     The dust collection unit  1  having the above structure is attached to the miter saw  10  as shown in  FIG. 2  by fitting the coupling cylinder  3  of the lid  6  into the dust ejection port  12  of the miter saw  10 . Accordingly, the dust collection unit  1  functions to collect chips and residues generated from the workpiece  16  when the miter saw  1  is operating.  
         [0037]     The next description will be made for explaining an operation of the miter saw  10 . To cut the workpiece W with the miter saw  10 , the saw blade  14  is first driven by the electric motor to rotate in the direction of the arrow shown in  FIG. 2 . And the saw blade  14  is then pushed down with the housing  13  about the shaft  17 , the saw blade  14  cuts the workpiece  16 . Chips and residues generated from the workpiece W during the cutting process are moved in the direction of the arrow shown in  FIG. 2  in the saw cover  21  due to an inertial force and an air stream generated by the rotation of the saw blade  14 . The chips and residues are then carried into the dust collection unit  1  through the dust ejection port  12 .  
         [0038]     The dust collection unit  1  collects the chips and residues coming into the main casing  1 A through the coupling cylinder  3 . The air including the chips and residues and introduced into the main casing  1 A passes through the filter member  5  so that the only air is discharged into the atmosphere. Therefore, only the chips and residues are accumulated in the main casing  1 A. In this embodiment, the coupling cylinder  3  integral with the lid  6  faces the filter member  5  during the operation of the miter saw  10  so that this structure assists to separate the chips and residues from the efficiently.  
         [0039]     In order to throw out the chips and residues in the main casing  1 A, the operator holds the handle  7  with one hand and detaches the dust collection unit  1  from the miter saw  10 . More precisely, the operator pulls the entire dust collection unit  1  from the miter saw  10  and releases the engagement of the coupling cylinder  3  with the dust ejection port  12 . Thus, the dust collection unit  1  is detached from the miter saw  10 .  
         [0040]     The operator then holds the dust collection unit  1  with one hand and carries the same to the place where the chips and residues can be discarded. In this embodiment, the base member  2  is transparent or translucent so that the chips and residues accumulated in the main casing  1 A are visible from outside. Therefore, the operator easily determines when the chips and residues in the main casing  1 A should be discarded.  
         [0041]     When the chips and residues are discarded, the operator fist pushes the drive mechanism  4  against the bias force of the return spring  19 , while holding the handle  7  with one hand. Then, the engaging element  18  is released from the peripheral edge of the lid  6  so that the lid  6  rotates about the hinge  8  by virtue of the elastic force of the torsion coil spring provided at the hinge  8 . Accordingly, the dust ejection port  20  is opened as shown in  FIG. 6 . Then, as shown in  FIG. 7 , the operator maintains holding the dust collection unit  1  with one hand, while treating a garbage bag  11  with the other hand. When the operator turns the main casing  1 A upside down in order to face the dust ejection port  20  to the inside of the garbage bag  11 , the chips falls from the main casing  1 A into the garbage bag  11  through the dust ejection port  20 . As described above, the operator can discard the chips and residues into the bag  11  easily with the only one hand. Accordingly, the disregarding process for the chips and residues can be easily performed efficiently.  
         [0042]     After discarding the chips and residues from the dust collection unit  1  into the garbage bag  11 , the operator pivots the lid  6  about the hinge  8  to close the dust ejection port  20  with the lid  6 . The engaging element  18  is then engaged with the peripheral edge of the lid  6  to maintain the closing condition of the lid  6 , as illustrated in  FIG. 3 . When the operator again attaches the dust collection unit  1  to the miter saw  10 , as shown in  FIG. 2 , the operator cuts the workpiece again by the miter saw  10 .  
         [0043]     In this embodiment, the main casing  1 A has the base member  2  made of resin and the filter member  5  made of a soft bag attached to the base member  2 . If the dust collection unit  1  attached to the miter saw  10  is bumped against a wall during a transport of the miter saw  10 , the filter member  5  may deform to absorb an impact of the bump, thereby preventing both the dust collection unit  1  and the miter saw  10  from being damaged.  
         [0044]     As described above, the wire frame  9  assists in maintaining the filter member  5  in the developed shape, when the miter saw  10  is operated and when the dust collection unit  1  is disconnected from the miter saw  10 . Accordingly, dusts and residues from the workpiece can be reliably collected and discarded.  
         [0045]     With the above structure to fix the wire frame  9  to the base member  2 , the wire frame  9  can be firmly and reliably fixed to the base member  2 . The wire frame  9  does not slip off from the base member  2  during the use of the dust collection unit  1 . Thus, the filter member  5  can maintain the original bag shape at any time.  
         [0046]     The wire frame  9  may be removed to form the dust collection unit  1 .  FIG. 8  shows another embodiment of a base member  110  for the dust collection unit  1 . In this embodiment, the base member  110  is constituted by a ring frame  111  and a support frame  112  which is detachably fitted to one open end of the ring frame  111 . Both of the ring frame  111  and the support frame  112  are made of resin.  
         [0047]     The lid  6  is pivotably provided to the ring frame  111  with the hinge  8 . The support frame  112  has a ring portion  113  and a pair of bar portions  114 ,  114 . The bar portions  114 ,  114  extends from two positions of the ring member  113 , which are opposed to each other on an open end of the ring portion  113 , toward the bottom of the filter member  5 , respectively.  
         [0048]     The support frame  112  is inserted in the filter member  5 , while a rim of the filter member  5  is folded back so as to sheathe the ring portion  113 . The support frame  112  is then fitted to the ring frame  111 . The handle  7  is then attached and fixed to the bar portion  114  by screws from above the filter member  5  so that the drive mechanism  4  is detachably engaged with the rim of the lid  6  on the opposite side of the hinge  8 .  
         [0049]     The advantages of the second embodiment of the dust collection unit  1  having the base member  110  are the same as those of the first embodiment.  
         [0050]     As described above, when the dust collection unit is filled up with dust, the operator may hold the handle with one hand, remove the dust collection unit from the electric tool, and manipulate the drive mechanism provided near the handle with the same hand to open the dust ejection port easily. The operator can therefore discard the dust from the dust collection unit easily and efficiently, using only one hand.  
         [0051]     The main casing  1 A is made of transparent or translucent material so that the operator can look at the inside of the main casing  1 A. That is, the dust and residues accumulated in the main casing  1 A can be clearly seen from outside. Hence, the operator can know well when the dust should be discarded from the dust collection unit.  
         [0052]     To discard the dust and residues from the dust collection unit  1 , the operator only needs to operate the drive mechanism  4  with one hand, releasing the lid  6  and thereby opening the dust ejection port  20 . This helps to enhance the efficiency of discarding the dust and residues through the dust ejection port  20 .  
         [0053]     The coupling cylinder through which the chips and air flow pass faces the filter member for separating the chips from the air. This helps to separate the chips from the air at high efficiency.  
         [0054]     When the drive mechanism is operated with one hand to disengage the engaging element  18  from the lid  6 , the lid  6  automatically rotates by virtue of the bias force of the spring to open the dust ejection port  20 . The dust and residues can be easily discarded from the dust collection unit  1 .  
         [0055]     When the engaging element  18 , which is provided near the handle  7 , is operated against the bias of the return spring  19 , the engaging element  18  is released from the lid  6 . As a result, the dust ejection port  20  is opened. Therefore, the operator can efficiently discard the dust and residues from the dust collection unit  1 , using only one hand.  
         [0056]     The main casing  1 A includes the base member  2  and the filter member  5  that is a soft bag and attached to the base member  2 . Because the base member  2  and the filter member  5  are soft, the filter member  5  may deform if the dust collection unit  1  bumps on a wall during the transport of the electric tool  10  with the dust collection unit  1 . This structure prevents both of the dust collection unit  1  and the electric tool  10  from being damaged.  
         [0057]     The filter member  5  contains the wire frame  9  for maintaining the filter member  5  in a developed shape. Since the filter member  5  remains in the form of a bag when the dust is collected and when the dust is discarded. This structure helps to collect and discard the dust reliably.  
         [0058]     Since the wire frame  9  is secured to the base member  2 , the filter member  5  can be prevented from accidentally being released from the base member  2 . In other words, the wire frame  9  does not slip off from the base member  2  during the use of the dust collection unit  1 .  
         [0059]     The present invention is applicable to any electric tools which need a dust collection unit for collecting dust and residues.  
         [0060]     It is understood that the foregoing description and accompanying drawings set forth the embodiments of the invention at the present time. Various modifications, additions and alternative designs will, of course, become apparent to those skilled in the art in light of the foregoing teachings without departing from the spirit and scope of the disclosed invention. Thus, it should be appreciated that the invention is not limited to the disclosed embodiments but may be practiced within the full scope of the appended claims.