Abstract:
A dust collection system for use in connection with a portable power tool is provided. The dust collection system generally includes a dust collection port having an intake that is interconnected to an air impeller by an intake duct. The impeller is driven by a motor, to create a vacuum at the intake port of the dust collection port. The outlet of the air impeller is in communication with a dust collection volume. In operation, the dust collection system is fixed to a portable power tool. Dust created during sawing or other operations is collected by the dust collection port, and is drawn away from the location at which the dust is created by a vacuum established by the air impeller at the intake port. The dust thus collected is deposited in the dust collection volume, which may include a filter bag. The present invention provides for the efficient collection of potentially harmful particulates created during sawing or other operations, without adversely affecting the portability of the portable tool to which the system is affixed.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Priority is claimed from U.S. Provisional Patent Application Ser. No. 60/361,203, filed Mar. 1, 2002, entitled “PORTABLE DUST COLLECTION SYSTEM,” the entire disclosure of which is incorporated herein by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a portable dust collection system. In particular, the present invention relates to the collection of dust created by portable power tools. 
     BACKGROUND OF THE INVENTION 
     The maintenance of safe environments for workers is of increasing concern. One area that has received attention in connection with worker safety is the reduction of harmful airborne particulates. For example, particulates created during concrete sawing operations, include silica dust, have become subject to government interest and regulation. Accordingly, a need exists to reduce airborne particulates in connection with concrete sawing and other operations. 
     One application that often requires the sawing of concrete materials involves the use of concrete tiles as roofing material. During such operations, tiles are commonly cut to size using portable power saws. Because the blades used to cut concrete operate by abrading the concrete material, a large amount of dust is created. When such sawing is performed within a confined space, or in still air, the level of particulates in the vicinity of the worker performing the sawing operation can exceed government standards and levels suggested by safe work practices. 
     In order to provide for the safety of workers performing dust-producing activities, respirators that provide filtered air to a wearer have been employed. However, respirators require a tight fit in order to be effective. Accordingly, they are difficult to size and difficult to put on. In addition, the tight fit required to ensure the effectiveness of the respirator is often uncomfortable for the user. These issues, in addition to the high cost of effective respirators, typically results in workers foregoing the use of such devices. 
     In order to prevent dust from entering the environment during sawing operations, shops having stationary tools may install elaborate fixed dust collection systems. However, such systems are not adaptable for use in connection with portable devices 
     In order to control the dispersion of particulates created using portable power hand tools, collection bags have been used. However, existing systems are ineffective when used in connection with relatively fine particles, such as are created during concrete sawing operations. Other systems have been proposed that provide intakes that can be interconnected to a vacuum. However, such systems are inefficient, and do not provide a vacuum and dust collection bag system that is integrated with the portable power tool. 
     Accordingly, a need exists for a method and an apparatus to eliminate or reduce airborne particulate levels during sawing, sanding, and drilling operations performed using portable power tools. In particular, there is a need for a method and an apparatus for collecting particles produced during sawing, sanding and drilling operations that does not hinder the use of a portable power tool. Furthermore, there is a need for such a method and an apparatus that is reliable in operation and inexpensive to implement. 
     SUMMARY 
     In accordance with the present invention, a portable dust collection system for use in connection with portable power tools is provided. The system of the present invention generally provides an intake positioned near the location at which dust is produced by a portable power tool when that tool is in use. In addition, the system includes a motor that drives an impeller. The impeller is used to create a vacuum at the intake, and therefore to draw particulates into the intake. A dust collection volume is positioned at an outlet of the impeller to collect particulates drawn into the system at the inlet. The dust collection system is configured for mounting on a portable power tool, without significantly affecting normal use of the power tool or the portability of the power tool, while providing control of airborne particulates. 
     In accordance with an embodiment of the present invention, the intake is formed as part of or operates in cooperation with a dust collection plate or member. The dust collection plate is attached to the bottom of the foot of the saw. The inlet may be positioned in front of the saw blade, so that debris created during sawing operations will tend to be ejected towards the dust collection intake. In accordance with a further embodiment of the present invention, the dust collection intake may be positioned so that its opening is perpendicular to the foot of the saw. 
     According to embodiments of the present invention, operation of the portable dust collection system may be synchronized to operation of the saw. In particular, the switch used to control operation of the saw may also be used to control operation of the portable dust collection system. 
     In accordance with an embodiment of the present invention, a portable dust collection system is provided in the form of a kit, containing the component parts necessary to provide dust collection in connection with a portable, handheld saw. Accordingly, a dust collection plate assembly that can be affixed to the foot of a saw and having an integral or integrated dust collection port is provided. An impeller assembly that includes a bracket for conveniently attaching the impeller assembly to a portable saw is also provided. The impeller assembly includes a dust collector power supply cord. The power supply cord may be wired into the power supply switch of the saw. A replacement handle member that includes a recess or hole to provide access to the power supply switch by the dust collector power supply cord may also be included in the kit. Furthermore, a dust collection tube, such as in the form of a flexible hose, may be provided for interconnecting the dust collection port to the intake of the impeller assembly. Typically, a dust collection volume, for example in the form of a bag, is provided for connection to the outlet of the impeller assembly, to collect particles collected by the dust collection system. Various additional fasteners and components may also be provided as part of the kit. For example, an adaptor plate may be provided to assist in affixing the dust collection plate to the foot of the saw. 
     The present invention additionally provides a method for controlling dust created during sawing operations using portable saws. According to the method, a dust collection port is positioned in front of the saw blade of a portable saw, such that a significant proportion of the debris created during sawing operations is directed towards the dust collection port. According to embodiments of the present invention, the method includes positioning the dust collection port at or below a plane defined by the foot of the saw. The method additionally includes creating a vacuum at the dust collection port, and depositing particles collected at the dust collection port in a dust collection volume. 
     Additional advantages of the present invention will become readily apparent from the following discussion, particularly when taken together with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a left side elevation of a portable dust collection system in accordance with an embodiment of the present invention, interconnected to a portable circular saw; 
     FIG. 1B is a left side elevation of a portable dust collection system in accordance with another embodiment of the present invention, interconnected to a portable circular saw; 
     FIG. 2A is a bottom perspective view of the intake and dust collection plate of the embodiment of FIG. 1A; 
     FIG. 2B is a bottom perspective view of the intake and dust collection plate of the embodiment of FIG. 1B; 
     FIG. 3A is a right side elevation of the embodiment of FIG. 1A; 
     FIG. 3B is a right side elevation of the embodiment of FIG. 1B; 
     FIG. 4 illustrates the components of a portable dust collection kit in accordance with an embodiment of the present invention; and 
     FIG. 5 depicts the use of a portable saw having a portable dust collection system in accordance with an embodiment of the present invention to cut a piece of material. 
    
    
     DETAILED DESCRIPTION 
     With reference now to FIGS. 1A and 1B, embodiments of a portable dust or particle collection system  100  in accordance with the present invention are illustrated, interconnected to a portable circular saw  104 . In general, a portable dust collection system  100  in accordance with the present invention includes a dust or particle collection plate assembly  108  having or interconnected to a dust collection outlet  110 , that is in turn interconnected to an air impeller housing  112  inlet port  114  by a dust collection tube  1116 . In addition, the dust collection system  100  includes an impeller motor  120 , such as a high speed electric motor, for driving the air impeller. The air impeller, air impeller housing  112  and the motor  120  comprise an impeller assembly  122 . Power may be supplied to the motor  120  by a dust collection power supply cord  126 . The impeller assembly  122  further includes a discharge or outlet port  124  that is interconnected to a dust or particle collection volume  128 . In accordance with an embodiment of the dust collection system  100  illustrated in FIG. 1, the dust collection volume  128  is a dust collection bag. 
     The portable saw  104  generally includes a saw motor  132 , a motor housing  134 , a saw blade  136 , and a base plate or foot  140 . The bottom surface  142  of the base plate or foot  140  defines a plane. As can be appreciated by one of skill in the art, the saw  104  and/or material to be cut is positioned so that the material to be cut is adjacent the bottom surface  142  of the base plate  140 . Accordingly, sawing or cutting operations take place on a side of the plane defined by the foot  140  opposite the motor  132 . A saw power supply cord  144  may be provided for interconnecting the portable saw  104  to a source of electrical power. A power supply switch  148  allows the operator to selectively operate the saw  104 . In accordance with an embodiment of the present invention, the saw power supply cord  144  supplies power to both the saw motor  132  used to operate the saw blade  136 , and the impeller motor  120  used to rotate the impeller of the portable dust collection system  100 . In addition, the power supply switch  148  may operate both the portable saw  104  and the portable dust collection system  100 . Accordingly, the dust collector power supply cord  126  may be wired into the power supply switch  148 . Alternatively, a separate power supply switch may be provided for operating the dust collection system  100 . 
     The portable saw  104  will also generally include a handle  152 , an auxiliary handle  156 , an upper guard  160 , a moveable lower guard  164 , and a lower guard lift lever  168 . A depth adjustment mechanism  164  and a bevel adjustment mechanism  168  may also be provided. 
     In general, the portable dust collection system  100  is fixed to the portable saw  104 . For instance, the dust collection plate assembly  108  may be fixed to the base plate  140  of the portable saw  104 . The impeller assembly  122  is, according to the embodiments illustrated in FIGS. 1A and 1B, fixed to the portable saw  104  by a mounting bracket  312  (shown in FIGS.  3 A and  3 B). Therefore, the portable dust collection system  100  generally moves as a unit with the portable saw  104 . 
     With reference now to FIG. 2A, an embodiment of the portable dust collection system  100  illustrated in FIG. 1A shown interconnected to a portable saw  104  from a bottom perspective view. In FIG. 2A, the dust collection plate assembly  108  can be seen to include a dust collection intake port  204 , and dust collection shields or skirts  208   a - 208   e  formed along the sides of a dust collection plate  207 , defining an intake volume  209 . A slot  210  may be formed in the dust collection plate assembly  108  to provide clearance for the saw blade  136 . The dust collection plate assembly  108  may be formed from a durable material. For example, the dust collection plate assembly  108  may comprise a dust collection plate  207  made from steel or another metal with folded sides to form the skirts  208 . Also visible in FIG. 2A are fasteners  212 , which fix the dust collection plate assembly  108  to the saw base plate  140 . As shown in FIG. 2A, an embodiment of the portable dust collection system  100  may position the dust collection intake port  204  ahead of the saw blade  136  and in a plane that is substantially parallel to the plane of the bottom surface  142  of the base plate  140 . The skirts  208  are generally perpendicular to the plane defined by the bottom surface  142  of the base plate  140  to promote the collection of debris created during sawing operations at the dust collection intake port  204 . 
     With reference now to FIG. 2B, an embodiment of the portable dust collection system  100  illustrated in FIG. 1B is shown interconnected to a portable saw  104  from a bottom perspective view. In FIG. 2B, the dust collection plate assembly  108  includes a dust collection intake port  204  having an opening  216  that is substantially perpendicular to the plane defined by the bottom surface  142  of the saw base plate  140 . Dust collection shields or skirts  208  are provided as part of the dust collection plate assembly  108  to form an intake volume  209 . In accordance with an embodiment of the present invention, the dust collection plate  207  is formed from metal and has integral skirts  208 . 
     In operation, the saw blade  136  rotates in a clockwise direction when viewed from the side of the portable saw  104  illustrated in FIGS. 1 and 2. Furthermore, it can be appreciated that particles created during sawing operations generally travel in a direction that is tangential to the saw blade  136  at the point of contact between the saw blade  136  and the material in which the cut is being made, and in the same direction that the saw blade  136  is traveling. Accordingly, the dust collection intake port  204  is advantageously positioned as shown in the embodiments illustrated in FIGS. 1A,  1 B,  2 A and  2 B to collect dust created during sawing operations. 
     With reference now to FIGS. 3A and 3B, the portable dust collection systems  100  and portable saw  104  illustrated in FIGS. 1A,  1 B,  2 A and  2 B are illustrated from the side opposite that illustrated in FIGS. 1A and 1B. In FIGS. 3A and 3B, the dust collection tube  116  can be seen interconnecting the dust collection outlet  110  of the dust collection plate assembly  108  to the inlet  114  of the air impeller  112 . Also visible in FIGS. 3A and 3B is the routing of the dust collection power supply cord  126 . In general, the dust collection power supply cord  126 , in the illustrated embodiments, interconnects the impeller motor  120  of the impeller assembly  122  to the saw power supply cord  144 . According to an embodiment of the present invention, the dust collector power supply cord  126  is interconnected to the saw power supply cord  144  through the saw&#39;s power supply switch  148 . Accordingly, the motor  120  is only operated when the saw  104 is in operation. Alternatively, the dust collector power supply cord  126  may be connected to the saw power supply cord  144  directly, allowing operation of the motor  120  of the air impeller assembly  122  independently of the saw  104 . According to still other embodiments of the present invention, the dust collector power supply cord  126  may be independently interconnected to an external source of power. 
     In accordance with embodiments of the present invention, the dust collector power supply cord  126  is attached to the saw  104  at various locations, to ensure that the dust collector power supply cord  126  does not interfere with operation of the saw  104 . For example, tabs  302  for holding the dust collector power supply cord  126  may be affixed to the saw  104  using fasteners that are already provided as part of the saw  104 . For example, fasteners  304  used to affix the auxiliary handle  156  to the motor housing  134  may also be used to secure such a tab  302 . For embodiments in which the dust collector power supply cord  126  is interconnected to the saw power supply cord  144 , either directly or through the power supply switch  148 , a removable half  306  of the handle  152  may be provided with a hole or recess  308  where the dust collector power supply cord  126  enters the handle  152 . 
     Also visible in FIGS. 3A and 3B is a impeller assembly mounting bracket  312 . The impeller mounting bracket  312  may be interconnected to the gear housing  316  of the saw  104 . In accordance with an embodiment of the present invention, the impeller assembly mounting bracket  312  is mounted to the gear housing  316  using fasteners and corresponding holes provided as part of the saw  104 . According to still other embodiments, extended length fasteners are provided to replace fasteners included as part of the saw  104 , to accommodate the thickness of the bracket  312 . 
     With reference now to FIG. 4, a kit  400 , the components of which can be interconnected to a portable saw to form a portable dust collection system  100  in accordance with an embodiment of the present invention are illustrated. As shown in FIG.  4 , the major components of the portable dust collection system  100  include the dust collection plate assembly  108 , the air impeller assembly  122 , and dust collection volume  128 . The kit  400  may additionally include a removable half  306  of the handle  152  that provides a recess or hole  308  for receiving the dust collector power supply cord  126 . Furthermore, embodiments of the kit  400  may provide an adaptor bracket  404  to assist in affixing the dust collection plate assembly  108  to a saw  104 . 
     As depicted in FIG. 4, the dust collection plate assembly  108  provided as a part of a kit  400  may have an integral dust collection outlet  110 , or may have a separate dust collection outlet  110  that is already affixed to the dust collection plate  207 . Furthermore, the dust collection tube  116  may already be interconnected to the dust collection outlet  110 . Alternatively, the various components of the dust collection plate assembly  108  may be provided separately for assembly by the user. 
     The impeller assembly  122  is generally provided as a preassembled unit. The impeller assembly  122  thus includes an impeller motor  120  and attached impeller (not shown) located within the air impeller housing  112 , which provides an inlet  114  and an outlet  124 . In addition, the impeller assembly  122  may include a motor housing  408  to protect the motor  120  and to provide a durable impeller assembly  122 . The mounting bracket  312  may then be rigidly affixed to the housing  408 . Alternatively or in addition, the mounting bracket  312  may be interconnected to the remainder of the impeller assembly  122  by fasteners  412  that may also be used to secure various components of the impeller assembly  122  to one another. The impeller assembly  122  is further provided with a dust collector power supply cord  126 , ready for interconnection to the saw power supply cord  144 . 
     The dust collection volume  128  may be provided with a mating fixture  416 , to provide for the convenient interconnection of the bag  128  to the outlet  124  of the impeller assembly  122 . The dust collection volume  128  may be interconnected to the fixture  416  by a clamp  420  and/or an adhesive. As can be appreciated by one of skill in the art, the mating fixture  416  may alternatively be provided as part of the impeller assembly  122 . The dust collection volume  128  may comprise a bag that is made from or incorporates a material that is capable of filtering and thus removing particles created during sawing operations and provided to the interior of the dust collection volume  128  by the outlet,  124 . 
     The use of a dust collection &#39;system  100  in connection with a portable saw  104  is depicted in FIG.  5 . In general, the portable dust collection system  100  is operated in conjunction with operation of the portable saw  104 . That is, when the portable saw  104  is being used to perform a cutting operation, the dust collection system  100  is turned on to collect dust generated during the cutting operation. Accordingly, as noted above, the dust collection system  100  and the portable saw  104  may share a single power switch  148  and power supply cord  144 . When power is supplied to the portable dust collection system  100 , the impeller motor  120  operates to rotate the air impeller. In particular, the motor  120  may rotate a turbine or squirrel cage-type unit, or any other configuration of air impeller, capable of displacing air. Operation of the air impeller by the motor  120  creates a vacuum at the inlet  114  of the air impeller housing  112 . The inlet  114  is interconnected to the dust collection intake  108  by the dust collection tube  116 . Accordingly, a vacuum is formed at the dust collection port  204 . This vacuum draws dust and particles  504  created at the interface between the saw blade  136  and the material  508  being cut into the dust collection port  204 . As shown by arrow  512  in FIG. 5, the outside edge of the blade  136  generally travels from the point of contact with the material being cut towards the dust collection port  204 . Accordingly, the dust collection port  204  is advantageously positioned to collect dust and particles  504 , and to therefore reduce the amount of dust and particles  504  entering the atmosphere. 
     The dust and particles  504  collected by the dust collection port  204  is drawn through the dust collection tube  116 , the inlet  308 , past the air impeller, and out the impeller outlet  124 . The dust is then collected in a collection volume  128 . For example, the collection volume  128  may comprise a filter bag that is capable of filtering from the air stream particulates and dust  504  collected at the dust collection port  208 . The dust collection volume  128  may be removed from the air impeller outlet  124  for emptying or disposal. In accordance with another embodiment of the present invention, the dust collection volume  128  comprises a centrifuge-type air filter. 
     The present invention also provides a method for collecting dust, particles and debris created during sawing or cutting operations. According to the method, a vacuum is created in a volume adjacent to the point at which a saw blade or other component of a cutting device contacts a material being cut. For example, where the method is employed in connection with a circular saw, the vacuum is created in an area towards which debris created during the sawing operation is directed by the saw blade. In order to promote the collection of debris at the intake port, skirting may be provided. 
     The vacuum is created using an impeller driven by a motor. The motor may be provided separately, or may be the same motor used to power the saw blade. Dust collected at the inlet is deposited in a dust collection volume. 
     Although the embodiments of the present invention that are particularly useful in connection with a circular saw have been discussed, the invention is not so limited. For example, the present invention may be adapted for use in connection with portable drills, sanders, or reciprocating saws. In addition, the present invention is not limited for used in connection with corded power tools. For instance, the present invention may be used in connection with battery-operated portable tools. Furthermore, the present invention may be provided with a dedicated battery-type power supply for operation of the motor  120 . As yet a further embodiment, the present invention may draw power for the motor  120  from the same source used to power the portable device, but using a separate interconnection to that source. In addition to battery-type power supplies, fuel cell-type power supplies may be used. 
     In accordance with yet another embodiment of the present invention, the air impeller may be driven by the same motor utilized to actuate the cutting mechanism of the portable device. For example, the air impeller may be driven through a belt and pulley arrangement, or other power takeoff arrangement, from the motor used to move the cutting or abrading surface of a portable power tool. In general, the present invention may be applied in connection with any portable power tool in connection with which the control of dust created through use of the power tool is desirable. Furthermore, embodiments of the present invention provide a dust collection system that can easily be added to a portable saw. 
     The foregoing discussion of the invention has been presented for purposes of illustration and description. Further, the description is not intended to limit the invention to the form disclosed herein. Consequently, variations and modifications commensurate with the above teachings, within the skill and knowledge of the relevant art, are within the scope of the present invention. The embodiments described hereinabove are further intended to explain the best mode presently known of practicing the invention and to enable others skilled in the art to utilize the invention in such or in other embodiments and with various modifications required by their particular application or use of the invention. It is intended that the appended claims be construed to include the alternative embodiments to the extent permitted by the prior art.