Patent Description:
Power saws of the "cut-off" variety have been known for some time that employ a rotating circular blade applied to a stationary workpiece, such as wood, masonry or stone materials. An early version of a radial saw was invented by Raymond De Walt in <NUM>. These types of saws further include what is known as a "chop saw" which may be used for cutting lengths of pipe, steel, and other masonry objects. The chop saw comprises a motor coupled to a circular blade (or grinding wheel) pivotally supported for manual arcuate movement relative to a supporting surface such as a worktable.

An example of systems and methods comprising a chop saw are disclosed in <CIT>. Some additional features known for chop saws include compounding the blade to change its angle with respect to the horizontal plane; or a sliding compound feature so that the blade can make larger cuts relative to a circular blade diameter. Some chop saws further employ a laser guide such as the configuration disclosed in <CIT>.

Also known, is a problem of uncontrolled release of and exposure to airborne dust and particulate matter resulting from cutting a workpiece. Accordingly, government agencies such as the Occupational Safety and Health Administration (OSHA) have promulgated safety and health requirements for wet and dry cutting. The California Occupational Safety and Health Act of <NUM> (Cal/OSHA) requires employers to provide a safe and healthful work place and gives Cal/OSHA regulatory jurisdiction over all public and private employers in California. Henceforth, employers must be compliant with all regulations set forth in Title <NUM> of The California Code of Regulations. In addition to health issues, the dust by-products present a clean-up challenge, even if all individuals in a contained environment have donned respirators.

Development of wet cutting devices and methods is one solution to dust abatement. In doing so, water is applied at a blade cutting edge where dust is entrained to a fluid and directed to a holding area. While most wet cutting methods work relatively well, they create additional problems of waste water pollution and environmental concerns. Further, the slurry created will adhere to cutting tool materials and components that also require periodic cleaning.

Many prior art solutions have been proposed that specifically employ dry means to control dust. Examples of such designs include, "Cutting And Dust Collecting Assembly," by <CIT>, "Cutting Apparatus with Dust Discharging," to <CIT>, "Dust-Free Masonry Cutting Tool," to<CIT>, "Dust Collector for A Power Tool," by <CIT>, to name a few. Such solutions generally may be suitable for their general purposes however none of these solutions are applicable for a chop saw. Yet another similar device was proposed by one of the present inventors, Guth entitled "Dust Collection System for A Masonry Saw," <CIT>. This dust abatement design is applicable to a masonry chop saw; however this design is not easily portable and requires a separate hook up to a vacuum system.

In light of the above, it is an object of the present invention to provide a Chop Saw with Dust Collection that is highly portable and lighter in weight as compared prior art solutions. More specifically, it is an object of the present invention to provide a masonry chop saw that integrates dust collection to a single portable unit. It is still a further object of the present invention to provide a dry dust collection design that is easily cleaned. It is still further an object of the present invention to provide a design that includes a variety of innovative features over prior designs. US Patent Publication No. <CIT> describes a chop saw with dust collection system. DE Patent Publication No. <CIT> describes a gas filter which comprises fan-fold panels. <CIT> describes a lightweight filter.

The invention is defined in claim <NUM>, preferred embodiments are defined in dependent claims <NUM>-<NUM>. The present invention specifically addresses and alleviates the above mentioned deficiencies, more specifically, the present disclosure in a first aspect, refers to a cut off saw comprising: a worktable for supporting a work piece; a rotatable arm fixed to a circular saw blade and pivotably secured to the worktable; a center slot carved out of the worktable axially aligned to the circular saw blade; a vacuum apparatus at an interior of the worktable, the vacuum apparatus providing negative pressure with respect to atmosphere at the center slot and collecting dust from the work piece created as a byproduct from use of the cut off saw.

This example is additionally characterized in that worktable further comprises: a saw motor mechanically coupled to a circular saw blade; an upper housing; and a lower dust bin connected below the upper housing, the upper housing and lower dust bin each including a front panel, a back panel and first and second lateral sides, wherein the upper housing further comprises a lateral partitioning wall extending from first and second later sides, the lateral partitioning wall defining a suction chamber below the center slot, and wherein the upper housing further comprises a transverse partitioning wall defining both a vacuum motor chamber and a tilter chamber.

This example is additionally characterized wherein each of the upper housing front panel and upper housing back panel further comprises a lifting handle, each of the lifting handles comprising an indentation in the upper housing front and back panels. In addition to the center slot, the worktable further comprises a plurality of blade slots angularly aligned to the center slot.

The cut off saw is further characterized wherein the filter chamber comprises: an access panel covering an area carved out of the first lateral side; a filter cleaning knob connected to a first filter end cap via a connection bolt, the connection bolt penetrating a hole in the access panel; a panel bushing providing translational and rotational support to the connection bolt; a second filter end cap, the first and second filter end caps together securing ends of a cylindrical media tilter; a vacuum suction tube connected to the vacuum apparatus, the vacuum tube penetrating the transverse partitioning wall; and an annular rim protrusion extending from the vacuum suction tube, the annular rim protrusion mating with the second filter end cap via a gasket and a bearing, the second filter end cap further comprising a bearing seat acting as an abutment to the bearing.

Still further, the example is characterized wherein the upper housing comprises a lower rim, the lower rim comprising a groove around a perimeter thereof, and wherein the lower dust bin further comprises an upper rim, the upper rim comprising a groove around a perimeter thereof, and wherein the upper and lower rims comprising grooves are matingly and removably connected to each other.

Yet further, the example is characterized wherein the lower dust bin first and second lateral sides each comprise a lifting handle, the lifting handles each comprising an indentation in the first and second lateral sides, respectively; and wherein the lower dust bin further comprises a latch for securing the lower dust bin to the upper housing.

In a second aspect, an example is a cut off saw comprising: a worktable for supporting a work piece; a saw motor mechanically coupled to a circular saw blade; a rotatable arm fixed to the circular saw blade and pivotably secured to the worktable; a filter chamber at an interior to the worktable, the filter chamber comprising: a cylindrical media filter; and a vacuum tube coupled to an interior of the cylindrical media filter providing negative pressure with respect to atmosphere to said interior of the cylindrical media filter.

The cut off saw in this example may be further characterized in that the worktable further comprises: a center slot carved out of the worktable axially aligned to the circular saw blade; and a plurality of blade slots angularly aligned to the center slot. Further, the filter chamber further comprises a filter cleaning flap secured to a lateral partitioning wall at an interior of the filter chamber, the cylindrical filter media having a plurality pleated segments about a cylindrical surface, wherein the filter cleaning flap contacts the pleated segments when the filter cleaning knob is rotated. Also, the filter chamber further comprises: an access panel covering an area carved out of the first lateral side; and a filter cleaning knob connected to a first filter end cap via a connection bolt, the connection bolt penetrating a hole in the access panel. Still further, the filter chamber further comprises: a panel bushing providing translational and rotational support to the connection bolt; and a second filter end cap, the first and second filter end caps together securing ends of a cylindrical media filter. Yet still further, the filter chamber further comprises: a vacuum suction tube connected to the vacuum apparatus, the vacuum tube penetrating the transverse partitioning wall; and an annular rim protrusion extending from the vacuum suction tube, the annular rim protrusion mating with the second filter end cap via a gasket and a bearing, the second filter end cap further comprising a bearing seat acting as an abutment to the bearing. To facilitate portability of the cut off saw, the invention additionally comprises two or more wheels.

In a third aspect, an example may comprise a method for cutting masonry objects comprising the steps of: mounting a circular saw blade pivotably with respect to a worktable; carving out a center slot in the worktable aligned to the circular saw blade; aligning a plurality of side slots at an angle to the center slot; imparting a negative pressure with respect to atmosphere to an interior of the worktable; and collecting dust through the center slot and the side slots from the work piece created as a byproduct from use of the circular saw blade.

The method herein may be additionally characterized as comprising: providing start-lip current to a first motor; providing start-up current to a second motor start-lip current to a first motor; providing start-up current to a second motor sequentially to minimize undesirable current surges; providing a cylindrical filter below the worktable; and filtering the dust from air passing through the cylindrical filter. The method additionally comprises pleating the cylindrical filter thereby increasing usable surface area of the cylindrical filter.

Still further, the method for cutting masonry objects herein may be characterized as comprising: contacting a filter cleaning flap to the cylindrical filter; rotating a filter cleaning knob; clearing dust from the cylindrical filter; and collecting dust in a dust bin located at an area below the worktable. Also the method includes connecting a vacuum tube to a center area of the cylindrical filter; imparting a negative pressure with respect to atmosphere to a center area of the cylindrical filter; and exhausting filtered air to a lateral side of the worktable. Another method step includes providing a plurality of lifting handles at lateral sides of the worktable.

In yet another aspect of the disclosure, an apparatus comprising a cylindrical filter, a filter cleaning knob, and a filter cleaning flap is disclosed. Within such embodiment, the filter cleaning knob is configured to rotate the cylindrical filter. The filter cleaning flap is coupled to the cylindrical filter and configured to sequentially make contact with a plurality of pleated segments of the cylindrical filter as the filter cleaning knob is rotated.

The novel features of this invention, as well as the invention itself, both as to its structure and its operation, will be best understood from the accompanying drawings, taken in conjunction with the accompanying description, in which similar reference characters refer to similar parts, and in which:.

Referring initially to <FIG>, an example <NUM> comprises a cut-off type saw which is configured to cut masonry, and more specifically stones, bricks, pavers, and other masonry items. It should be understood that inventive concepts herein can also apply to woodworking circular saws and additionally saws for cutting plastic and roofing. The dust collection system <NUM> works in connection with a specifically configured saw <NUM>, with a unique cutting table <NUM> and dust collector arrangement. The saw may be a cut-off saw or a chop saw, which has a circular toothed blade <NUM> or grinding wheel, and which rotates in a vertical plane of rotation as shown. The cut-off saw is further mounted on a pivotable arm <NUM> which allows the saw to be raised and lowered from a non-cutting position onto a cutting position so that the blade contacts a masonry work piece <NUM>, and is lowered through the work piece <NUM> as the saw blade cuts.

In the <FIG> example saw <NUM> is shown coupled to a saw motor <NUM>. It should be further appreciated that a similar circular saw could be coupled to a belt or pulley system for driving the saw <NUM>. Still further, saw <NUM> is provided with a cutting table <NUM> which includes a blade center slot <NUM>. As the cutting blade passes through the work piece, the blade continues until it enters the center slot <NUM>; and additionally passes through the surface of the cutting table <NUM> into the slot <NUM>. Cutting table <NUM> should be broadly construed as a substantially flat structure supporting a workpiece.

As circular blade <NUM> teeth engage the work piece <NUM> (<FIG>), dust and particulate matter <NUM> are ejected from the work piece in various directions. A negative pressure provided by vacuum apparatus <NUM> (<FIG>) causes air to flow in a downward direction thereby curtailing outward dispersion of the dust and particulate matter <NUM>. In conventional prior art systems, the saw blade <NUM> would not pass through a blade slot, and thus ejected material would strike the cutting table and be collected after striking the cutting table. In the saw and dust collection system <NUM> of the present invention, a powerful flow of air is directed past the cutting blade <NUM>, through center slot <NUM> and angled side slots <NUM> and into a filter chamber <NUM> below the cutting table <NUM>. Also importantly, a flow of air is provided to remove dust at the instant the workpiece <NUM> is contacted by the saw blade <NUM>] and throughout the cutting thereof.

With reference to <FIG>, a rear perspective view of the example is shown. Exhaust port <NUM> is provided for discharge of filtered air <NUM>. Air vents <NUM> provide for ventilation and heat transfer from vacuum apparatus <NUM>. Lifting handles <NUM>, <NUM> are further provided on first and second lateral sides to assist portability of the unit <NUM>. Electrical connections <NUM> allow for external power to be supplied to the device <NUM> as shown.

In a preferred example system <NUM> additionally comprises two motors <NUM>, <NUM>; a first <NUM> that drives the saw blade <NUM> and a second <NUM> that provides a prime mover for air flow. The saw and collection system <NUM> of the present invention may will reduce a likelihood that the system <NUM> current surge causes a circuit breaker to be tripped. It is to be noted that although saw has been mentioned in the main part of the description herein, it is not being mentioned in the claims, and therefore, is not part of the invention.

Also as shown in <FIG> and in <FIG>, the worktable <NUM> has two separable units, namely upper housing <NUM> and lower dust bin <NUM>. In addition to lifting handles <NUM>, <NUM> on lateral sides, lifting handles <NUM> are provided on a front and a back of the unit <NUM> to also serve as hand holds for a user transporting the device. Latch <NUM> is provided to secure upper housing <NUM> to lower dust bin <NUM> also as shown in <FIG>.

With reference to <FIG>, a sectional view taken along line <NUM>-<NUM> in <FIG> is shown. Particulate matter <NUM> from workpiece <NUM> is drawn through center slot <NUM> and angled side slot <NUM>. It should also be appreciated that side slot could be aligned parallel to the center slot <NUM> and at right angles thereto. Air containing dust <NUM> flows as shown by directional arrows <NUM> around partitioning wall <NUM>. Dust <NUM> is fm1her filtered from the air through cylindrical pleated filter <NUM>. Some of the dust and particulate matter will fall to dust bin <NUM> and some will be trapped by the filter. Filter cleaning flap <NUM> is provided connected to a ledge <NUM> adjacent to partitioning wall <NUM>. The cleaning flap <NUM> will assist in clearing the cylindrical filter <NUM> when a user rotates knob <NUM>. Translational wall <NUM> serves to separate filter chamber <NUM> from vacuum chamber <NUM>. Exhaust hose <NUM> is shown in the vacuum chamber <NUM> for exhausting air to an exterior of the device <NUM>. The vacuum apparatus <NUM> may use various types of motors to generate negative pressure and CFM to include blower motor, centrifugal fan, squirrel cage fan, propeller fan, or any other conventional moving device.

<FIG> similarly shows the flow of air with directional arrows <NUM> as a sectional view along line <NUM>-<NUM> of <FIG>. A cutaway in translational wall <NUM> reveals filter compartment <NUM>. It will be appreciated that other configurations for filter chamber <NUM> and vacuum chamber <NUM> could be well within the scope of the present invention, such as, for example the filter chamber <NUM> configured directly below slots <NUM>, <NUM>.

<FIG> shows a closer view of the embodiment <NUM> in the <FIG> illustration. The cut-a-way view also reveals a perspective illustration of the pleated cylindrical filter <NUM>. A carve out in a lateral side of upper housing <NUM> is provided to accommodate access panel <NUM>. Filter cleaning knob <NUM> is connected to the cylindrical filter <NUM> through the access panel <NUM> as further illustrated in <FIG>. Access panel <NUM> can further be removed for maintenance and disassembly of the cylindrical filter <NUM> for replacement or deep cleaning. <FIG> shows an end view of filter cleaning knob <NUM>.

<FIG> illustrates more specifically how a cylindrical filter <NUM> connects to a vacuum apparatus <NUM> via vacuum tube <NUM> penetrating transverse wall <NUM>. Initially, filter <NUM> is supported on it is sides by filter end caps <NUM>, <NUM>. Knob <NUM> connects to the first end cap <NUM> via coupler spacing <NUM> and connection bolt <NUM>. Panel bushing <NUM> provides translational and rotational support to connection bolt <NUM>. Hexagonal nut <NUM> secures the first filter end cap <NUM>. At the other end, vacuum tube <NUM> has an annular rim <NUM> protruding therefrom and provides an abutment for bearing <NUM> also supported by gasket <NUM>. Recess <NUM> in the second filter end cap <NUM> provides the space to connect bearing <NUM> around rim <NUM> as shown. However, it is to be noted that the embodiment shown in <FIG> does not form part of the invention, and is not covered by the claims.

<FIG> provide a more detailed view of how upper housing <NUM> connects to lower dust bin <NUM>. Rim <NUM> mates with groove <NUM> as shown for a secure connection upon closure of latch <NUM>. An inside of the dust bin <NUM> shows an area where dust ultimately settles for later removal.

In another aspect of the disclosure, particular configurations of the aforementioned cylindrical filter <NUM> are contemplated. To this end, it should be noted that conventional air filters are inherently problematic because during their use they become saturated with dust and debris which at some point significantly reduces airflow. As previously disclosed herein, a filter pleat agitator mechanism (e.g., flap <NUM>) may be included to periodically clean the aforementioned cylindrical filters in place by rotating these filters against the filter pleat agitator mechanism which would dislodge dust/debris and thus increase filter efficiency.

This rotational cleaning method, however, creates the problem of sealing the cylindrical filter to the intake port while still allowing it to rotate. In addition, it would be desirable for this rotating filter/seal to endure in an extreme environment of high temperature, high vibration, and micro fine dust. It would be further desirable that the seal material is chosen such that it does not damage the intake port during the rotation process or from the high vibration environment.

Referring next to <FIG>, an exemplary cylindrical filter with a seal configured for such extreme environments is provided in accordance with an aspect of the disclosure. As illustrated in <FIG>, cylindrical filter <NUM> comprises an intake port <NUM>, wherein intake port <NUM> may be configured to facilitate the illustrated air flow via a vacuum suction tube (e.g., vacuum suction tube <NUM>) coupled to a vacuum device. It is also contemplated that cylindrical filter <NUM> further includes annular seal <NUM>, wherein annular seal <NUM> is firmly embedded within end cap <NUM> by annular seal retainer <NUM>.

Here, it should be appreciated that cylindrical filter <NUM> illustrated in <FIG> is substantially similar to the aforementioned cylindrical filter <NUM>, wherein the structure and functionality of cylindrical filter <NUM> is substantially similar to cylindrical filter <NUM>. For instance, similar to cylindrical filter <NUM>, it is contemplated that cylindrical filter <NUM> is configured to rotate against a filter pleat agitator mechanism (e.g., flap <NUM>) for the purpose of cleaning dust and debris from the filter pleats of filter media <NUM> to increase filter efficiency. It is further contemplated that gasket <NUM> illustrated in <FIG>, may be substantially similar to annular seal <NUM>, wherein annular seal <NUM> is made of material configured to maintain a vacuum tight seal and allow for rotation of cylindrical filter <NUM> in an extreme environment of high heat, high vibration, and micro fine dust. Moreover, it would be desirable to manufacture annular seal <NUM> from a substance that most mitigates the damaging effects to the intake port <NUM> of cylindrical filter <NUM> during rotation and/or within a high temperature/vibration environment.

In a particular aspect, it contemplated that annular seal <NUM> is made of a spongy foam-like material. For instance, annular seal <NUM> may be made of silicone foam. Indeed, as is well known, silicone foam has a wide operating temperature (e.g., temperature range of -<NUM>°F to <NUM>°F (-<NUM> to <NUM>)), and provides excellent dust sealing capabilities (e.g., it is well known that open cell and closed cell silicone foam products can be used for sealing out dust with low compressive forces). As is also generally known, silicone foam products are typically manufactured from platinum cured, liquid silicone rubber. The raw compound is expanded and dispensed on a continuous casting line, then heat cured. The expansion process is controlled to create a range of products having different densities, softness/firmness and cell structures. Open cell silicone foams are widely used for cushioning, dust sealing or light water sealing. Closed cell silicone foam materials are used for outdoor gaskets, wash-down gaskets and resilient cushioning pads. Expanded silicone foam products have a firmness range from ultra soft to extra firm, allowing engineers to select the best product for their application.

Claim 1:
An apparatus comprising: a cylindrical filter (<NUM>); and a filter cleaning knob (<NUM>) configured to rotate the cylindrical filter (<NUM>); a filter cleaning flap (<NUM>) coupled to the cylindrical filter (<NUM>) and configured to sequentially make contact with a plurality of pleated segments (<NUM>) of the cylindrical filter (<NUM>) as the filter cleaning knob (<NUM>) is rotated to facilitate dislodging dust and debris trapped by the cylindrical filter (<NUM>); and characterized in that the apparatus further comprises: an annular seal (<NUM>) encircling an intake port (<NUM>) of and configured to function as a diaphragm between the cylindrical filter (<NUM>) and the intake port (<NUM>), wherein the annular seal (<NUM>) is manufactured from silicon foam material to mitigate damage to the intake port (<NUM>) from a rotation of the cylindrical filter (<NUM>) and from vibrations.