Debris Collection and Spark-Arresting Device

The subject matter described herein relates, in general, to dust collection from a pneumatic handheld sanding tool and, more particularly, to a tool-mounted spark-arresting debris collection device.

As part of the manufacturing process of many goods, such as vehicles, the body of the object is smoothened via an abrasive sander. That is, initial manufacturing operations may roughly form the shape of a final product, but the surface may be rougher than desired or may include certain surface defects. A sanding tool creates a smoother surface finish for the product and/or removes surface imperfections.

A belt sander is a specific example of a sander that includes a continuous belt that is embedded with abrasive particles. Different materials may be used as abrasive particles, including flint, garnet, aluminum oxide, and emery. An actuator of the sander rotates the belt at high speeds. The actuator may take a variety of forms. For example, an electric motor may drive the belt. In another example, pneumatic pressure may cause the belt to rotate. In either case, at these high rotational speeds, the abrasive particles on the belt remove surface material from the product, providing a smoother object surface. In some examples, the abrasion or sanding tool can be used to remove surface imperfections such as burrs, welding relics, and other surface imperfections and/or smooth curves or edges.

In one embodiment, example systems relate to an improved debris collection system for a portable/handheld pneumatic sanding tool. The debris collection device includes a duct housing detachably connectable to a pneumatic sanding tool. The duct housing includes 1) a debris duct in communication with a debris discharge port of the pneumatic sanding tool and 2) an air duct in communication with an air vent of the pneumatic sanding tool. The debris collection device also includes a spark-arresting device. The spark-arresting device includes 1) a spark-arresting chamber in communication with the debris duct and 2) a toroidal manifold of air nozzles surrounding an exit of the spark-arresting chamber. The toroidal manifold is in communication with the air vent and the spark-arresting chamber. The debris collection device also includes a debris collection bin in communication with the spark-arresting device.

Devices associated with improving dust collection and fire hazard prevention in sanding operations are disclosed herein. As previously described, sanding is a regular operation in many manufacturing processes, whether to improve a surface finish or remove surface imperfections such as welding burrs, sharp edges, etc. During sanding, particulate matter such as wood dust and/or metallic flakes are removed from a surface. If not contained, this debris collects on and covers surfaces in the work area. The particulate matter could be inhaled by a technician, leading to negative short- or long-term health consequences and is generally an undesirable byproduct of the sanding process. Also, during the sanding operation, abrasive particles from the sander and fibers from the sanding belt may become dislodged and may disperse throughout a workspace and/or be inhaled by a technician. Moreover, when the sanded surface is metallic, the sanding operation may generate sparks or heated particulate matter that could ignite other particulate material and/or objects within the environment and the tool.

Accordingly, the present device collects dust and debris generated during sanding and removes such from the surrounding environment. The debris collection device also includes a centrifugal spark-arresting device to reduce the risk of metallic spark ignition of particulate matter in the sanding environment. In general, the debris collection device is a lightweight and compact dust and fiber-collecting device that is directly attached to an existing pneumatically-powered portable belt sander.

In general, the debris collection device uses the exhaust compressed air from a pneumatic sanding tool to create a negative pressure differential in the device. The pressure differential between the different regions of the device creates an airflow. The airflow carries the airborne dust and debris created by the sanding action of the pneumatic sanding tool to a cylindrical spark-arresting chamber. The dust-laden air enters the cylindrical spark-arresting chamber in a fashion that causes the air to swirl, resulting in a centrifugal force that draws the heavier dust and fiber material to the chamber walls for an extended period. This arrests the sparks that may have formed during sanding. The dust and debris travel towards a detachable collection bin, which uses a porous filter as a separating device, with air escaping and dust, abrasive belt fibers and other debris being retained for disposal.

Specifically, the debris collection device includes a spark-arresting chamber, an air injection manifold, and an outlet nozzle. An air duct and a debris duct are connected with the debris discharge port and air vent of the pneumatic sanding tool, respectively, and separately direct air and debris to a spark-arresting device. Sanding debris enters a spark-arresting chamber of the spark-arresting device while air enters an injection manifold of the spark-arresting device. The air injection manifold has a toroidal cavity with several small nozzles arranged in a circular pattern and directed away from the spark-arresting chamber. The spark-arresting chamber outlet narrows in diameter downstream of the air injection manifold. The narrow diameter of the spark-arresting chamber outlet forces the air streams from the nozzles to form a single stream of high-velocity, low-pressure air. This creates a region of low pressure in the spark-arresting chamber due to the Venturi effect that draws the cooled debris and air out of the spark-arresting chamber outlet towards the debris collection bin. The debris collection device also includes a hinged belt guard that protects a technician from ejected debris and sparks and generally guides the debris and sparks toward the debris collection bin. The belt guard is hinged to allow access to and removal of tool components such as the abrasive belt.

In this way, the disclosed device improves dust collection by being compact, lightweight, easily manipulated, and ergonomic. Moreover, the disclosed debris collection device is self-contained in that it does not rely on supplemental power or devices to generate the forces that collect dust and extinguish sparks. Instead, the exhaust air from the pneumatic tool generates the force that draws debris from the work area. The present debris collection device further prevents fire hazards by providing numerous mechanisms that promote spark elimination. Thus, the debris collection device protects an operator from debris inhalation and fire hazards that may result if sparks are not extinguished and promotes a clean, safe, and effective workspace.

Turning now to the figures,illustrates one embodiment of a spark-arresting debris collection deviceinstalled on a handheld pneumatic sanding tool. It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, the discussion outlines numerous specific details to provide a thorough understanding of the embodiments described herein. Those of skill in the art, however, will understand that the embodiments described herein may be practiced using various combinations of these elements. In any case, the debris collection deviceis implemented to perform methods and other functions as disclosed herein relating to improving dust collection from a handheld sanding tool.

A pneumatic sanding toolrelies on compressed air, rather than an electric motor, to drive the abrasive belt. As such, a pneumatic sanding toolmay be lighter and easier to maneuver around a workpiece than an electric sanding tool. A pneumatic sanding toolmay be desirable in a manufacturing facility where an operator spends many hours operating and moving the sanding tool.

As described above, debris is a byproduct of any sanding operation, whether the debris is material removed from a work surface or abrasive material that is dislodged from the belt. When the work surface is metallic, friction between the abrasive particles and the work surface may heat the metal flakes, forming sparks. The debris collection deviceof the present specification includes structural features that collect the debris to promote a clean and safe work environment and cool the sparks to prevent potential fire hazards.

Specifically, the debris collection deviceincludes a duct housingdetachably connectable to the pneumatic sanding tool. The duct housingincludes two separate channels, one for collected debris from the sanding operation and another for the exhaust compressed air used to drive the abrasive belt. That is, the pneumatic sanding toolincludes separate discharge ports for the debris and the exhaust compressed air and the duct housingmaintains these different flows separate from one another. Specifically, as depicted in, the duct housingincludes a debris duct that is in communication with a debris discharge port of the pneumatic sanding tooland an air duct that is in communication with an air vent of the pneumatic sanding tool. In an example, the debris duct and the air duct are directly adjacent to the discharge port and air vent, respectively. The duct housingmaintains the airflow and debris flow separate from one another. In an example, the duct housingis rigidly connected to the pneumatic sanding toolvia a number of attachment devices such as bolts, screws, or rivets.

The debris collection devicefurther includes a spark-arresting devicein communication with the duct housing. The spark-arresting deviceincludes a spark-arresting chamber where ignited particulate matter and/or sparks may cool and/or extinguish. The spark-arresting devicealso includes a toroidal manifold of air nozzles. The airflow out of the air nozzles 1) is directed away from the spark-arresting chamber and 2) generates a vacuum that draws debris away from the abrasive belt, through the duct housing, and ultimately towards the debris collection bin. Exhaust compressed air is fed to the toroidal manifold to generate the debris-moving airflow. In an example, the spark-arresting deviceis a separate component from the duct housingand is connected to the duct housingvia an adhesive or another fastening mechanism such as bolts, screws, or rivets. Additional details regarding the structure and operation of the spark-arresting deviceare provided below in connection with.

The debris collection devicefurther includes a debris collection binin communication with the spark-arresting device. The debris collection binmay be joined to the spark-arresting device. In general, the debris collection binincludes a porous cylindrical filter fastened to circular end plates. As depicted inbelow, air diffuses through the porous material filter while filtered debris is retained therein. The porous material filter may be formed of various synthetic and/or organic filter compounds, such as a woven matrix of plastic threads. The filter may have a porosity that allows air particles to diffuse but blocks larger dust and other debris particles.

In an example, the debris collection binmay be detachably connected to the spark-arresting device. For example, one plate of the debris collection binmay include threads that engage with corresponding threads on an outlet of the spark-arresting deviceto join the two together. Additional details regarding the debris collection binstructure are provided below in connection with.

The debris collection devicefurther includes a belt guardpivotally attached to the duct housing. The belt guardcovers a portion of the abrasive belt of the pneumatic sanding toolthat is on the opposite side of the abrasive belt from the spark-arresting deviceand the debris collection bin. As described above, particulate matter from the work surface or from the abrasive belt becomes dislodged during sanding. While some of the material is directed toward the debris collection bin, a portion may be directed elsewhere. The belt guardmay block a portion of the uncaptured material, thus promoting a clean and efficient workspace. The belt guardalso protects the operator from airborne debris. The belt guardalso retains the particulate matter in a region influenced by the debris collection device. That is, the belt guardmay generally maintain the particulate matter in a region surrounding the abrasive belt where the vacuum generated by the spark-arresting devicemay draw the debris towards the debris collection bin.

The belt guardalso protects the operator from potential injury that may result from contact with the abrasive belt. To remove material, the abrasive belt rotates at a high speed. Injury may occur if the operator were to touch the abrasive belt. Accordingly, the belt guardprevents the operator from touching the high-speed rotating abrasive belt.

In an example, the belt guardis pivotably attached to the duct housing. For example, a hinge pin may pass through respective bores in the duct housingand the belt guardin a fashion that allows the belt guardto pivot about the hinge pin. The hinged connection allows the belt guardto be moved out of position for belt replacement and/or repair. For example, during use, the belt guardis positioned as indicated by solid lines to protect the operator and capture dislodged particulate matter as described above. In this example, the belt guardmay include a clasp or other mechanism to secure the belt guardin place adjacent to the abrasive belt. During belt repair and/or replacement, an operator may disengage the clasp or other mechanism to pivot the belt guardto a disengaged position as depicted in dashed lines. In the disengaged position, the operator can repair and/or replace the abrasive belt and perform maintenance on other pneumatic sanding toolcomponents.

The debris collection devicecomponents may be formed of various materials. For example, the components may be formed of a lightweight plastic material such as a nylon-based material such as carbon fiber filled nylon and may be formed via three-dimensional (3D) printing. In another example, the components may be made of another material, such as aluminum. When made of aluminum, the debris collection devicemay further promote spark elimination as the metallic surface may draw heat away from the sparks.

In either case, the debris collection deviceof the present specification provides a compact, lightweight, and ergonomic device that removes dust and other debris from a work area and extinguishes sparks that may be generated during a sanding operation.

illustrates an exploded view of a portion of the spark-arresting debris collection device. Specifically,depicts the duct housing, spark-arresting device, and the debris collection bin. In an example, the duct housingis formed of two sub-housingsand. Portions of the debris ductand the air ductare formed in each sub-housingand, such that a continuous path is formed between 1) the debris discharge port and the spark-arresting chamber and 2) the air vent of the pneumatic sanding tooland the toroidal manifold. In an example, the second sub-housingis attached to the first sub-housingvia any number of fasteners such as screws, bolts, or rivets. In general, the duct housingmaintains the air ductand the debris ductseparate from one another while directing the debris away from a handle area of the pneumatic sanding tool. That is, the debris and the air follow different paths through the debris collection device, with the airflow generating the vacuum which draws the debris away from the abrasive belt.

also depicts the debris duct inletto the spark-arresting chamber of the spark-arresting deviceand the air duct inletto the toroidal manifold of the spark-arresting device. The second sub-housingmay be joined to the spark-arresting devicein several ways, including an adhesive.

also depicts the components of the debris collection bin. Specifically, the debris collection binincludes a pair of platesandthat serve as the structure around which a porous filteris attached to form a canister filter. In an example, each plateandhas a circumferential groove. The porous filtermay be positioned around the circumference of each plateandwith a cable tie or other band set in the grooves and tightened around the platesandto hold the porous filterin place. Whiledepicts the debris collection binas a multi-component device, in another example, the platesandand porous filtermay form a single integrated unit.

As described above, the debris collection binmay be detachably connected to the spark-arresting device, for example, to facilitate cleaning, filter replacement, and/or debris disposal. Accordingly, in one example, the first plateincludes internal threadsthat mate with external threadson the spark-arresting devicesuch that these components may be joined together or separated from one another.

illustrates a zoomed-in view of the duct housingand spark-arresting deviceof the spark-arresting debris collection device. Specifically,depicts the debris flow pathand the airflow paththrough these components. As described and as depicted in, the debris ductand air ductare separated from one another within the duct housing. This is due to the debris and air being directed to different regions of the spark-arresting device. Specifically, the debris flows through a debris discharge port of the pneumatic sanding tool, through the debris duct, and into the spark-arresting chamber, while the air flows through an air vent of the pneumatic sanding tool, through the air duct, and into the toroid manifold of the spark-arresting device.

As depicted in, the air ductand the debris ductchange the airflow direction and debris flow direction, respectively, by between 130 and 180 degrees. As a specific example, the air ductand debris ductmay change the airflow direction and the debris flow direction, respectively by 150 degrees. The spark-arresting devicechanges the airflow direction and the debris flow direction by 90 degrees. Doing so may facilitate a greater spark elimination effect. That is, changes in the flow path of sparks promote contact of the sparks with the walls of the ducts, which collisions may aid in cooling the sparks. Moreover, this arrangement increases the path of the debris, which may further aid in spark cooling as the sparks travel a longer distance before reaching the debris collection bin.

is a cross-sectional view of the spark-arresting deviceof the spark-arresting debris collection device. Specifically,is a cross-sectional view taken along the line-in.depicts the unique flow paths of the debris and the air into the spark-arresting device. Specifically, debris enters the spark-arresting chamberthrough a debris duct inlet, while the air enters the toroidal manifoldthrough an air duct inlet.

In general, the spark-arresting chamberis a volume where ignited particulate matter and sparks may cool down. A variety of structural features of the spark-arresting chamberfacilitate spark elimination. Specifically, the debris duct inletis off-center from the spark-arresting chambercenterline to induce swirling of debris within the spark-arresting chamberas indicated by the arrow. The collision of the sparks with the inner wall of the spark-arresting chambermay serve to cool some of the sparks. The cooling effect of this interaction is enhanced in the case where the spark-arresting deviceis formed of a metallic material such as aluminum, which draws heat away from the sparks. Moreover, the swirling motion of the debris in the spark-arresting chamberincreases the time the sparks are airborne before reaching the debris collection bin. As such, the sparks have more time to cool down.

As described above, the spark-arresting device includes a toroidal manifoldof air nozzlessurrounding an exit of the spark-arresting chamber. The toroidal manifoldis in communication with the air ductsuch that exhaust compressed air passes through the individual nozzlesof the toroidal manifold. The reduced size of the nozzlesrelative to the air ductand the air duct inletincreases the speed of the air exiting the nozzles. This creates a low-pressure or vacuum region downstream of the spark-arresting chamber. As the toroidal manifoldis in communication with the spark-arresting chamber, this low-pressure vacuum draws the swirling debris from the spark-arresting chamberout of the chamber and towards the spark-arresting deviceoutlet towards the debris collection bin. Additional details regarding the dust collection and spark cooling operations of the spark-arrest deviceand the debris collection binare described below in connection with.

is a cross-sectional view of the spark-arresting debris collection device. Specifically,depicts the air flow (depicted in dashed lines) and debris flow (depicted as long dash-short dash lines) through the spark-arresting deviceand the debris collection bin. As described above, the debris duct inletis offset from the centerline of the spark-arresting chamber, which promotes turbulence, or swirling of the debris and sparks (indicated as multi-pointed star shapes), within the spark-arresting chamber. This turbulence forces the dust, debris, and sparks against the interior wall of the spark-arresting chamber. Contact with the wall may extinguish some of the sparks.

Moreover, the turbulence of the swirling air may further extinguish sparks. That is, each spark may be surrounded by a pocket of heated air, which may be referred to as a thermal envelope. This thermal envelope insulates the spark and slows the heat dissipation rate from the spark. Turbulence in the spark-arresting chamberbreaks down the thermal envelope surrounding a spark. Without the thermal envelope insulating the spark, heat more rapidly dissipates such that the turbulence increases the rate of heat dissipation of a spark.

Moreover, the turbulence increases the time the sparks remain within the spark-arresting chamber. That is, rather than having a direct flow path from the debris duct inletto the outletof the spark-arresting device, the sparks remain in the spark-arresting chamber. This increased time allows the sparks to cool before entering the debris collection binand potentially igniting other debris.

In an example, the outlet of the spark-arresting chamberhas a smaller diameter than the main volume of the spark-arresting chamber. Specifically, the outlet diameterof the spark-arresting chamberis less than the main volume diameter. As an example, the outlet diametermay be between 20 and 25 millimeters (mm), for example, 22.15 mm, and the main volume diametermay be between 25-35 mm, for example, 30.15 mm. This structural arrangement may further cool sparks in the sanding debris. That is, before exiting the spark-arresting chamber, the vacuum pressure generated by the air passing through the toroidal manifoldmust overcome the centrifugal force generated by the turbulence within the spark-arresting chamber. Overcoming this centrifugal force may take time such that the sparks remain in the spark-arresting chamberand continue the spark-arresting turbulent motion within the spark-arresting chamberuntil the centrifugal force is overcome by the low pressure generated by the fast-flowing air out of the outlet.

As described above, airflow through the nozzlesof the toroidal manifoldgenerates the low pressure that draws the debris and sparks away from the abrasive belt. Specifically, the toroidal manifoldis a toroidal cavity in downstream communication with the spark-arresting chamber. The toroidal manifoldhas several small nozzles(e.g., 2.0 mm nozzles) arranged in a circular pattern and directed away from the spark-arresting chamber. The spark-arresting chambercontains an outlet which passes through the center of the toroidal manifoldto a spark-arresting device outlet. In an example, the spark-arresting device outletof the spark-arresting devicehas a tapered diameter that extends into the debris collection bin. Specifically, the spark-arresting device outletmay taper from a first diameter, which is between 25-35 mm, for example, 30.15 mm, to a second diameter, which is between 20 and 25 mm, for example, 22.15 mm. The small diameter of the nozzlescauses the many escaping air streams to travel at an increased velocity relative to the upstream flow. The narrow diameter of the spark-arresting device outletconverges these air streams to converge into a single stream of high-velocity and low-pressure fluid flow. This creates a region of low pressure immediately downstream of the spark-arresting chamberdue to the Venturi effect, which states that fluid pressure is reduced as fluid speed increases. As such, the increased fluid speed through a reduced cross-sectional area generates a low-pressure region in the spark-arresting device outlet. This pressure differential creates an airflow through the debris ductthat draws dust, debris, and sparks from sanding to the spark-arresting chamber. That is, as described, the toroidal manifoldis downstream of the spark-arresting chamberand generates a vacuum to draw debris through the debris ductand the spark-arresting chamber.

also depicts a cross-sectional view of the debris collection bin. As described above, the debris collection binis detachably connected to the spark-arresting devicevia the respective threadsandon the rigid leading plateof the debris collection bin and the spark-arresting device. In an example, the spark-arresting device outletof the spark-arresting deviceprotrudes a distance into the debris collection bin. Doing so prevents dust and debris from re-entering the spark-arresting deviceand potentially clogging the nozzlesor otherwise impeding the operation of the spark-arresting device.

As described above, the debris collection binis formed of a cylindrical filterformed of porous material through which air may permeate but which traps dust and other debris. The dust collection binfurther includes a rigid terminal plate. The rigid terminal platedeflects air and debris towards the filter. That is, as depicted in, the airflow generated through the toroidal manifoldand the spark-arresting device outletdirects the debris and air towards the terminal plate. Upon striking the terminal plate, the air and debris are directed toward the porous filter, where the debris is captured and the air is transmitted. The rigid terminal platealso absorbs the impact of the air and debris exiting the spark-arresting device outletto dampen the air stream and allow the filterto collect more of the debris while the air diffuses. In an example, the porous filtermay be formed of any porous material, such as a synthetic plastic matrix.

Detailed embodiments are disclosed herein. However, it is to be understood that the disclosed embodiments are intended only as examples. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the aspects herein in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of possible implementations. Various embodiments are shown in, but the embodiments are not limited to the illustrated structure or application.

The terms “a” and “an,” as used herein, are defined as one or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as comprising (i.e., open language). The phrase “at least one of . . . and . . . ” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. As an example, the phrase “at least one of A, B, and C” includes A only, B only, C only, or any combination thereof (e.g., AB, AC, BC or ABC).

Aspects herein can be embodied in other forms without departing from the spirit or essential attributes thereof. Accordingly, reference should be made to the following claims, rather than to the foregoing specification, as indicating the scope hereof.