Patent Document

CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a continuation application of U.S. patent application Ser. No. 10/951,454 filed Sep. 27, 2004, issuing as U.S. Pat. No. 7,000,515,which is a continuation of U.S. patent application Ser. No. 09/253,110 filed Feb. 19, 1999, and are incorporated by reference in their entireties. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     This invention relates to a movable, protective, sawdust collection hood for use with a table saw equipped with a rotary saw blade and, more particularly, to such a hood that provides a directed air stream for removal of sawdust generated by a saw blade rotating on a shaft located below a work table.  
         [0004]     2. Background Art  
         [0005]     Protective hoods have become widely used to remove sawdust generated by the cutting of a work piece on a rotary table saw, and to conduct the dust toward a sawdust collection receptacle. The hoods have additionally served to protect the user thereof from injury due to inadvertent contact with a rotating saw blade. Such hoods have generally taken the form of a longitudinally elongated enclosure, open at the bottom, having a pair of spaced-apart. vertical walls joined at their upper edges by a top wall, and adapted for placement over an exposed, upper peripheral portion of a saw blade, the saw blade being mounted for rotation on a shaft located below the work table of the table saw. Protective hoods of this kind have been configured such that air was drawn into the hood through an air intake opening (due to an air current created by rotation of the saw blade and/or by an attached vacuum or blower system), from whence air streamed across the blade and out a discharge opening toward a sawdust collection receptacle, carrying the sawdust away with it. Retractable apparatus was provided to support the hood in position over the saw blade--for example, by a link arm having one end attached to the hood and an opposite end attached to a splitter mounted to the table saw behind the saw blade. Attached to a front portion of the vertical walls was a forwardly inclined nose having horizontal leading and trailing edges, such that rearward advancement of a work piece toward and against the nose panel caused the hood to rise, and with further such movement of the work piece the trailing edge of the nose rested on and made sliding contact with an upper surface of the work piece. An example of protective hoods of this kind is disclosed in U.S. Pat. No. 4,576,072 to Terpstra et al. An alternative retractable support for such a protective hood, i.e., a parallelogram linkage and counterbalance mechanism, was disclosed in U.S. Pat. No. 4,875,398 to Taylor et al.  
         [0006]     Such heretofore known protective hoods, however, failed to adequately remove sawdust and chips generated at the final stage of a cutting operation. Initially, during a cutting operation, so long as a work piece progressed rearwardly under the hood, across the upper surface of the work table and past the saw blade, sawdust and chips generated within the hood remained confined within the hood to be carried away by the air stream within the hood. But, after the cutting of a work piece had progressed to the stage at which the forwardmost portion of the work piece had moved underneath and rearward of a front portion of the hood, a gap was created between the hood and the work piece, thereby permitting sawdust and chips to be thrown forward through the gap and to escape from the hood. My invention overcomes this problem by eliminating the gap at the final stage of cutting a work piece.  
       SUMMARY OF THE INVENTION  
       [0007]     According to the present invention there is provided a protective, sawdust collection hood for a table saw. The table saw is equipped in conventional fashion with a saw blade mounted for rotation on a shaft located below a horizontal work table, and having an exposed, peripheral portion thereof extending above the worktable and rotating toward the front side of the work table. The table saw is also equipped with a splitter mounted directly behind the saw blade. In a first embodiment, the hood is adapted for pivotal attachment to the splitter, whereby the hood can be moved between a retracted, storage position and a working position directly over and straddling the exposed portion of the saw blade. The hood includes a pair of spaced-apart, vertical side panels, each side panel having a front, central and rear portion. A forwardly inclined nose panel is mounted between front portions of the side panels, and has horizontal leading and trailing edges. An upper cowl is mounted between the side panels, and has a substantially vertical, front portion terminating at a forward edge that engages an upper surface of the nose panel, and has a rearwardly extending, upwardly inclined portion terminating at a rear edge. A lower cowl is mounted between the side panels below the upper cowl and has a substantially vertical, front portion and rearwardly extending, substantially horizontal, central and rear portions. The front portion of the lower cowl terminates in a horizontal forward edge disposed above the trailing edge of the nose panel. A pair of vertical side skirts are provided, each of the skirts being movable between a first, lowered position and a second, raised position, and means are attached to the side panels for suspending a side skirt from each of the side panels. In this first embodiment, each of the side skirts has a substantially vertical slot, and the means for suspending the side skirts include a slot pin attached to and extending laterally outward from a central portion of the adjacent side panel, retainer means attached to each slot pin for retaining the pin within the slot, and stop means attached to the side skirts for limiting the downward movement of the side skirts when the hood is raised away from the work table. The side panels, upper cowl, lower cowl, and side skirts are made of a rigid transparent material so that an operator of the table saw can see through the hood to monitor cutting operations.  
         [0008]     During the initial stages of cutting a work piece, the side skirts are in the lowered position, the lower edge of each skirt being just even with the trailing edge of the nose panel. As the work piece is then moved rearwardly across the work table toward and against the nose panel, the hood rises until the trailing edge of the nose panel rests upon an upper surface of the work piece, thereby completing the initial stage. There then follows an intermediate cutting stage, wherein the work piece progresses rearwardly toward and past the saw blade with the trailing edge continuing to rest on, and make sliding contact with an upper surface of the work piece. During the intermediate stage, the side skirts remain in the lowered position. The final cutting stage occurs when the forwardmost portion of the work piece has been moved rearward underneath the side skirts and has fully cleared the nose panel; at that time the nose panel drops down to the work table, thereby closing the gap that would otherwise exist between the upper surface of the work table and the hood, and the side skirts move up into the raised position. Thereafter, once the work piece has fully cleared the saw blade and the side skirts, the side skirts also drop down from the raised position to the lowered position and come to rest on the work table. The cut having been completed, the cut portions of the work piece can then be removed from the work table.  
         [0009]     Throughout each of the stages of cutting a work piece, sawdust is carried by a directed stream of air away from the situs of cutting within the hood and toward a sawdust collection receptacle. Air enters the hood through an intake opening defined by rear portions of the side skirts and a rear portion of the lower cowl, thence streams forward over the work piece and saw blade and through an orifice defined by the forward edge of the lower cowl, the trailing edge of the nose panel and the front portions of the side panels, and thereafter is conducted rearwardly between an upper surface of the lower cowl and a lower surface of the upper cowl to exit the hood. In this manner, sawdust and chips generated by cutting a work piece, including that generated in the final stage of cutting, remains confined within the hood while being conducted toward a collection receptacle.  
         [0010]     Although rotation of the saw blade is sufficient to create the above-described air stream, the air stream flow rate can be increased by attaching a vacuum source to the hood. Therefore, in a preferred embodiment, the hood further includes a rear discharge wall mounted between an upper surface of a central portion of the lower cowl and the rear edge of the upper cowl. The rear discharge wall has an air discharge hole. A vacuum hose adapter is attached to a rear surface of the rear discharge wall and is aligned with the air discharge hole. A vacuum hose having one end connected to the adapter, and an opposite end attached to a shop vacuum or other vacuum source, provides vacuum suction to the hood for increased air flow through the hood.  
         [0011]     In a second embodiment of the hood, the hood is pivotally attached to the splitter by two pairs of parallel, equal-length links, forming a parallelogram linkage. In this embodiment, each of the slots in the side skirts is arcuate and the above-described means for suspending the side skirts further includes a first pair of parallel, equal-length, skirt support arms disposed on opposite sides of the hood, each of said support arms having a first end pivotally attached to a side panel and a second, opposite end pivotally attached to a front portion of a side skirt; and said means further includes a second pair of parallel, equal-length, skirt support arms disposed on opposite sides of the hood, each of said support arms having a first end pivotally attached to a side panel and a second, opposite end pivotally attached to an upper rear portion of a side skirt.  
         [0012]     In a third embodiment, the hood further includes a vacuum conduit assembly for drawing sawdust and wood chips away from the saw blade and through the hood to a collection receptacle. A collar joint is provided for pivotally attaching a rear portion of the hood to the vacuum conduit assembly, which permits rotation of the hood about a horizontal axis between a raised, storage position and a lowered, working position. The vacuum conduit assembly comprises a vacuum source connected to an electric power source; a laterally disposed, elongated, cylindrical, hollow boom having an intake end and an opposite discharge end; a hollow, cylindrical head stock mounted to the intake end of the boom and coaxial therewith, said head stock having an intake duct extension in communication with the interior of the head stock, and said intake duct being attached to, and in communication with, the collar joint; a movable vacuum hose within the boom, having a first, intake end storable within the head stock, and an opposite, discharge end with an attached hose end ring seal that is slidable within the boom; and a stationary vacuum hose having one end attached to the discharge end of the boom and an opposite end attached to the vacuum source. In this manner, a vacuum created by the vacuum source is communicated through the stationary and movable hoses to the head stock and thence to the hood.  
         [0013]     The collar joint comprises a first, semicylindrical, partial collar attached to an intake end of the vacuum conduit assembly, said partial collar being axially-aligned on a lateral axis A′-A′ and extending between rear portions of the side panels, and said collar having longitudinally-aligned, front and rear openings. The collar joint further comprises a second, semicylindrical, partial collar that partially surrounds and engages the first partial collar. The second partial collar is rotatable about the lateral axis A′-A′ and about a front, exterior surface of the first partial collar. The second partial collar is mounted between a rear edge of the lower cowl and a rear edge of the upper cowl, and is laterally disposed between rear portions of the side panels. The second partial collar has an air discharge hole that is in register with the front opening of the first partial collar when the hood is in a working position directly over and straddling the saw blade. A collar pin is laterally inserted along axis A′-A′ through the rear portions of the side panels, through tab projections from the intake end of the vacuum conduit assembly, and through the first and second partial collars. Preferably, the boom comprises a stationary portion and, in telescoping relation thereto, a laterally movable portion. The laterally movable portion of the boom is attached to the head stock. A rack and pinion assembly couples the laterally movable portion to the stationary portion of the boom, thereby permitting lateral adjustments of the position of the hood with respect to the saw blade and fence. A normally-closed, momentary switch, wired in series with the vacuum electric power source, is mounted on the head stock, such that, whenever the hood is moved to the raised, storage position adjacent the head stock, the momentary switch is opened, thereby de-energizing the vacuum source. For locking the hood in the raised, storage position, the nose panel has a retainer aperture engagable by a spring catch mounted on the head stock. The head stock is provided with a removable cap, whereby, with the cap removed, the intake end of the movable vacuum hose may be withdrawn from the head stock and used to vacuum clean the table saw and its immediate environs, and thereafter replaced inside the head stock.  
         [0014]     Important objectives of the present invention therefore include the following:  
         [0015]     It is an object of the invention to provide a protective hood for a rotary table saw that carries sawdust and chips away from the situs of cutting and toward a sawdust receptacle, even during the final stage of cutting a work piece.  
         [0016]     It is a further object of the invention to provide such a protective hood that is movable between a retracted and a working position directly over and straddling the saw blade.  
         [0017]     The above and other aspects and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]      FIG. 1  is a perspective view of a rotary table saw as viewed from a position at the front, left of the saw, and showing a first embodiment of the movable, protective hood, mounted by a single pivot to a splitter, and in a working position resting upon the work table;  
         [0019]      FIG. 2A  is an enlarged, left side view thereof;  
         [0020]      FIG. 2B  is an enlarged top plan view thereof;  
         [0021]      FIG. 2C  is an enlarged, rear elevational view thereof;  
         [0022]      FIG. 3A  is a left side view thereof showing the hood in a raised, working position after a work piece has been moved rearwardly under the nose panel and partially underneath the side skirts, preparatory to entering upon cutting by a rotating saw blade, and further showing the side skirts in a lowered position relative to the nose panel;  
         [0023]      FIG. 3B  is a left side view thereof, after the work piece has moved rearwardly under the nose panel and underneath the side skirts, showing the side skirts in a raised position;  
         [0024]      FIG. 3C  is a left side view thereof, showing the hood dropped down onto the work table with the side skirts still in a raised position, the forwardmost portion of the work piece having moved past the saw blade but not yet having cleared the side skirts; and  
         [0025]      FIG. 3D  is a left side view of the hood after the forwardmost portion of the work piece has cleared the side skirts, showing the side skirts returned to a lowered position.  
         [0026]      FIG. 4  is a cross sectional view of the hood of  FIG. 2A  taken along the line  4 - 4 .  
         [0027]      FIG. 5  is a left side elevational view of one side panel of the hood removed from the first embodiment of the hood.  
         [0028]      FIG. 6  is a left side elevational view of one side skirt of the hood removed from the first embodiment of the hood.  
         [0029]      FIG. 7  is a left side elevational view of a second, alternative embodiment of the hood, pivotally connected by parallelogram linkage to the splitter, and shown in a lowered, working position, resting on the work table;  
         [0030]      FIG. 8  is a left side elevational view thereof in a raised, retracted position.  
         [0031]      FIG. 9  is a perspective view of a rotary table saw as viewed from a position at the front, left of the saw, and showing the third embodiment of the movable, protective hood in a lowered, working position, and mounted by a collar joint to an overhead vacuum conduit assembly;  
         [0032]      FIG. 10  is an enlarged, partial, left side perspective view, thereof, but with the hood in a raised, storage position;  
         [0033]      FIG. 11  is a further enlarged, left side perspective view of the hood, showing the collar joint in phantom outline; and  
         [0034]      FIG. 12  is an enlarged, perspective view of a rear portion of the same hood, after removal of the collar pin and disassembly of the collar joint;  
         [0035]      FIG. 13A  is an enlarged, partial, left side elevational view thereof, showing the hood in a lowered, working position;  
         [0036]      FIG. 13B  is an enlarged, partial, left side elevational view thereof, showing the hood partially raised by a work piece advancing toward, but not yet in contact with, a rotating saw blade;  
         [0037]      FIG. 13C  is an enlarged, partial, left side elevational view thereof, after the work piece has moved rearwardly under the nose panel and underneath the side skirts, showing the side skirts in a raised position;  
         [0038]      FIG. 13D  is an enlarged, partial, left side elevational view thereof, showing the hood dropped down onto the work table just after the forwardmost portion of the work piece has cleared the nose panel, and further showing the side skirts still in a raised position relative to the nose panel; and  
         [0039]      FIG. 13E  is an enlarged, partial, left side elevational view thereof, showing the work piece having advanced further rearward, entirely clearing the hood, and the side skirts having dropped back down onto the work table.  
         [0040]      FIG. 14  is an exploded view of the collar joint and attached vacuum conduit assembly.  
         [0041]      FIG. 15  is a left side view of the third embodiment of the hood, showing the head stock rotated up to a retracted position.  
         [0042]      FIG. 16  is a left side view of the second embodiment of the hood attached by a parallelogram linkage and counterbalance to an overhead boom. 
     
    
       [0043]     The terms “front” and “forward” will be understood to refer to portions of the hood and the table saw that are depicted on the right of  FIG. 2A , and the terms “rear” and “rearward” refer to portions that are depicted on the left therein.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0044]     Referring now to  FIGS. 1, 2A ,  2 B and  2 C, a movable, protective hood  10 , denoted generally by the numeral  10 , is shown in a working position directly over and straddling a rotary saw blade  12  mounted on a drive shaft  14  located below a flat, horizontal work table  16  of a rotary table saw  18 . An exposed, upper, peripheral portion  12 P of the saw blade  12  protrudes through a slot (not shown) in the work table  16  and, as denoted by arrow  22 , rotates forwardly toward a front edge  16 F of the work table  16 . The table saw  18  is equipped with a splitter  24 , shown in dashed outline, mounted to a rear portion  16 R of the work table  16 . The splitter  24  is aligned with, and disposed directly behind, the saw blade  12 . In this first embodiment of the hood, the hood  10  is pivotally mounted to the splitter  24 , as described below.  
         [0045]     The hood  10  comprises a pair of spaced-apart vertical side panels  30  of identical size and shape, each side panel being longitudinally elongated from front to rear and having front and rear portions joined by an intermediate central portion, denoted as  30 F,  30 R,  30 C, respectively, as may best be seen in left side elevational view in  FIG. 5 , wherein, for ease of reference, the defined portions are depicted as being divided one from the next by vertical dashed lines V. Each of the side panels  30  are relatively thin, flat, and of uniform thickness, as may be seen in  FIGS. 2B and 2C . In this first embodiment, the rear portion  30 R is rectangular, being defined by a relatively long, lower edge  30 L and a relatively short, upper horizontal edge  32 , and by a relatively short, rear vertical edge  34  extending between terminuses  36 ′,  36 ″ of lower edge  30 L and upper edge  32 , respectively. The upper edge  32  extends forward about one-third the length of the lower edge  30 L from rear terminus  36 ″ to a front terminus  38 . In addition to lower edge  30 L, the central portion is defined by a substantially straight, upper edge  40  that is upwardly and rearwardly canted from the front portion  30 F, and defined further by a concave, forwardly and upwardly canted, rear edge  42  that extends from terminus  38  and intersects upper edge  40  at terminus  46 . The front portion  30 F extends generally forwardly of, and below, the lower edge  30 L. The front portion  30 F is defined by a straight, substantially vertical, rear edge  50  that extends downward from a forward terminus  52  of the lower edge  30 L to a lower terminus  54 ; a forwardly and upwardly canted nose edge  56  that extends from terminus  54  to a terminus  58 ; and a concavely curved upper edge  60  that extends rearwardly from terminus  58  to terminus  44 .  
         [0046]     The hood  10  further comprises a forwardly and upwardly inclined nose panel  70  mounted between the front portions  3 OF of the side panels  30  adjacent the nose edges  56  and extending from terminuses  54  to  58  thereof. The nose panel  70  has a horizontal leading edge  72  extending laterally between terminuses  58  and a horizontal trailing edge  74  extending laterally between terminuses  54 . The trailing edge  74  is horizontally chamfered, as are the nose edges  56  adjacent terminuses  54 , to facilitate smooth, sliding contact with an upper surface of a work piece  15  when moved underneath the hood  10  in the direction of arrow  23  during a cutting operation; see  FIG. 3A .  
         [0047]     An upper cowl  80  is mounted between the side panels  30 , and extends rearwardly and upwardly from the front portion  30 F and over the central portion  30 C thereof. A front portion  80 F of the upper cowl  80  has a forward edge  82  that engages an upper surface of the nose panel  70  at a location intermediate between the leading and trailing edges  72 ,  74 . The front portion  80 F extends upwardly from forward edge  82  and thence rearwardly to terminuses  44 . From terminuses  44  the central portion  80 C extends upwardly and rearwardly, adjacent upper edges  40 , to terminuses  46 .  
         [0048]     A lower cowl  90  is mounted between the side panels  30  below the upper cowl  80 . The lower cowl  90  has a substantially vertical, front portion  90 F and a rearwardly extending, substantially horizontal, central and rear portion  90 C,  90 R, the front portion  90 F terminating in a horizontal, forward edge  92  disposed above the trailing edge  74  of the nose panel  70 . The combination of the side panel front portions  30 F, the nose panel  70  and the forward edge  92  of the lower cowl  90  define an orifice  110  to permit air and sawdust to stream away from the saw blade  12  and the situs of cutting S; see, for example,  FIGS. 3A and 4 .  
         [0049]     One each of a pair of vertical side skirts  120  of identical size and shape is suspended from an exterior surface of each of the side panels  30 , and is movable between a first, lowered position, as depicted, for example, in  FIGS. 2A, 2C ,  3 A, and  3 C, and a second, raised position, as depicted in  FIG. 3B . Referring particularly to  FIG. 6 , each side skirt  120  is a thin, flat panel of uniform thickness, elongated from front to rear, and defined by a substantially vertical rear edge  122 , a convex leading edge  128 , a straight, horizontal lower edge  120 L extending rearward from a lower end of the leading edge  128  to a lower end of the vertical rear edge  122 , and a substantially horizontal upper edge  126  extending rearward from an upper end of the leading edge  128  to an upper end of the rear edge  122 .  
         [0050]     In this first embodiment, a parallel pair of horizontal, elongated, reinforcement struts  169  are attached to, and extend longitudinally along, opposite sides of an upper portion  24 U of the splitter  24 . Each of the struts  169  is made of metal, preferably aluminum. A parallel pair of equal-length, pivot arms  127 , are disposed on opposite sides of the pair of struts  169 . The arms  127  are also preferably aluminum. Each of the arms  127  has a first end pivotally attached to the splitter  24  by a first pivot pin  171  that extends laterally along an axis A-A through aligned apertures in said first ends, the splitter  24  and the struts  169 . Each of the arms  127  has an opposite, second end rigidly attached to a side panel  30 . Accordingly, the hood  10  may be rotated about lateral axis A-A between a raised, storage position and a lowered, working position.  
         [0051]     For this first embodiment, each of the side skirts  120  has a slot  99 , which preferably is canted forwardly and upwardly at about 30 degrees declination from vertical. A preferred means for suspending each side skirt  120  from an adjacent side panel  30  includes a slot pin  101  attached to, and extending laterally outward from, a central portion of said side panel  30  and through said slot  99 . Each slot pin  101  has a retainer means for retaining the pin  101  within the slot  99  and for retaining a side skirt  120  adjacent to the nearest side panel  30 ; for this purpose, preferably each slot pin  101  has an internally threaded recess for receiving a round head bolt in threaded engagement therewithin, a retaining washer being interposed between the head of the bolt and an exterior surface of the side skirt  120 . The means  140  further includes stop means  103  attached to the side skirts  120  for limiting the extent of downward movement of the side skirts  120  when the hood  10  is raised away from the work table  16 . The stop means  103  preferably comprises a longitudinally-elongated barrier attached to an upper, rear edge  126  of each of the side skirts  120  and cantilevered laterally inward over the adjacent upper rear edges of the side panels  30  for abutting engagement therewith when the skirts  120  are in a lowered position.  
         [0052]     The first embodiment of the hood  10  further includes a rear discharge wall  150  mounted between an upper surface of a central portion  90 C of the lower cowl  90  and the rear edge  159  of the upper cowl  80 , and between central portions  30 C of the side panels  30 . The rear discharge wall  150  has a centrally disposed hole  153  to permit air and sawdust to exit the hood  10 . A vacuum hose adapter  152  is attached to a rear surface of the rear discharge wall  150  and is aligned with the hole  153  therein. As shown in  FIG. 1 , one end of a vacuum hose  200  attaches to the adapter  152  and an opposite end thereof attaches to a vacuum source, such as a shop vac  202 .  
         [0053]     In a second, alternative embodiment of the hood  10 , as depicted in  FIGS. 7 and 8 , the hood  10  is pivotally attached to the splitter  24  by a parallelogram linkage for movement between a raised, storage position ( FIG. 8 ) and a lowered, working position ( FIG. 7 ). The second embodiment includes a first parallel pair of equal-length, link arms  127 , disposed on opposite sides of the splitter  24  and the hood  10 . Each of the arms  127  has a first end pivotally attached to the splitter  24  by a first pivot pin  171  that extends laterally through aligned apertures in said first ends and the splitter  24 , and each of the arms  127  has an opposite, second end pivotally attached to a side panel  30  by a second pivot pin  173 . The second embodiment, however, further includes a second, parallel pair of equal-length link arms  170  disposed on opposite sides of the hood  10  and the splitter  24 ; each of the link arms  170  has a first end that is pivotally attached to a front portion  24 F of the splitter  24  by a third pivot pin  175 , and a second end pivotally attached to an inside surface of a side panel  30  below the lower cowl  90  by a fourth pivot pin  177 . Thus, the second pair of link arms  170  cooperate with the first pair of link arms  127  to form a parallelogram linkage of the hood  10  to the splitter  24 . A Optionally, a coil spring  61  is longitudinally mounted between the splitter  24  and a rear portion of the lower cowl  90 , to assist in raising the hood  10  away from the work table  16 . In the second embodiment, the means for suspending the side skirts  120  from the side panels  30  is modified from that of the first embodiment in two ways: first, each of the slots  99 A is made arcuate; second, said suspension means further includes a parallelogram linkage of each side skirt  120  to the adjacent side panel  30 . The parallelogram linkage of the side panels  30  to the adjacent side skirts  120  includes a first pair  151  and, longitudinally spaced-apart therefrom, a second pair  149  of parallel, equal-length, skirt support arms, the arms  151 ,  149  of each pair being disposed on opposite sides of the hood  10  and pivotally attached to the side panels  30  and to the adjacent side skirts  120 . Preferably, each of the arms  151 ,  149  is apertured, as are the side panels  30 , at each point of pivotal attachment, and each pivotal attachment is made by a fifth pivot pin  60  inserted therethrough.  
         [0054]     In a third embodiment of the hood  10 , depicted in  FIGS. 9-15 , the hood  10  is pivotally attached by a collar joint  201  to an overhead vacuum conduit assembly  199 . The conduit assembly  199  includes a vacuum source  202  connected to an electric power source (not shown), a laterally disposed, elongated, cylindrical, hollow boom  203 , and a hollow head stock  205  attached to one end of the boom  203 . A movable vacuum hose  200  within the boom  203  has a discharge end that terminates in a ring seal  197  and an opposite, intake end that is normally stored within the head stock  205 . The ring seal  197  has an outer diameter slightly less than the inner diameter of the boom  203  in order to maintain a vacuum throughout the interior of the boom  203 . The ring seal  197  is slidable within the boom  203 , its extent of travel being limited by a lock plate  153 P within the head stock  205 . A vacuum source  202  is attached to the discharge end of the boom  203  by a stationary hose  200 ′ that inserts into an annular seal  39  at said discharge end. An intake duct  206  extends from the head stock  205  part way toward the work table  16 . The interior of the intake duct  206  communicates with the interior of the head stock  205  and with the movable hose  200  therein. The intake duct  206  has a front wall  207  and a rear wall  208  joined by side walls  209  and terminates distally in an intake opening defined by the side walls  209 , a rear wall  208 , and a partially cutout, front wall  207 , such that distal portions of the side walls  209  form tab extensions  206 T of the intake duct  206 . A first, semicylindrical, partial collar  236  is mounted between the tab extensions  206 T of the intake duct  206  and is axially aligned on lateral axis A′-A′. The first partial collar  236  has front and rear openings  236 F,  236 R. The rear opening  236 R of the partial collar  236  is defined by the distal margins of the front and rear walls  207 ,  208  of the intake duct  206 ; the front opening  236 F of the collar  236  is diametrically opposite to the rear opening  236 R. The collar joint  201  further includes a second, semicylindrical, partial collar  234 , coaxial with the first partial collar  236 , that partially surrounds and engages a forward portion of the first partial collar  236 . The second partial collar  234  is vertically disposed between a rear edge  157  of the lower cowl  90  and a rear edge  159  of the upper cowl  80 , and is laterally disposed between rear portions of the side panels  30 . A collar pin  237 , aligned on axis A′-A′, is inserted through apertures in the side panels  230  and through apertures  233  in the tab extensions  206 T of the intake duct  206  for rotatably mounting the second partial collar  234  to the first partial collar  236  and the intake duct  206 . The second partial collar  234  has an air discharge hole  235  that is in register with the front opening  236 F of the first partial collar  236  whenever the hood  10  is moved to a lowered, working position; whereas, whenever the hood  10  is moved to a raised, storage position, the second partial collar  234  covers over and closes off the front opening  236 F of the first partial collar  236 . Accordingly, when the hood  10  is in a lowered, working position, saw dust and wood chips are conducted from the situs of cutting S by an air stream (denoted by arrows  21 ) through the orifice  110 , rearwardly between the lower cowl  90  and the upper cowl  80 , thence through the discharge opening  235  of the second partial collar  234 , through the front and rear openings of the first partial collar  236 F,  236 R, through the intake duct  206  and vacuum hose  200  to a collection receptacle  202 . For directional control of larger particulates generated at the cutting situs S, preferably one or more forwardly and downwardly inclined deflector panels  223  are placed above the entrance to the orifice  110 , each of the deflector panels  223  being laterally disposed between the side panels  30 .  
         [0055]     The boom  203  of the vacuum conduit assembly  199  includes a stationary portion  203 S and, in telescoping relation thereto, a laterally movable portion  203 M that carries, and communicates with, the head stock  205 . A rack and pinion assembly  238 , equipped with an adjusting knob  238 K, is attached to the stationary and movable portions of the boom  203 S,  203 M, respectively, to permit lateral adjustments of the position of the hood  10  with respect to the saw blade  12  and fence  161 . A lock knob  238 L inserted into threaded hole  238 H reversibly locks portion  203 M to portion  203 S. For storing the hood  10  in a raised position adjacent the head stock  205 , a spring catch  217  is mounted on the head stock  205  for insertion into a retainer aperture  219  in the nose panel  70 . A normally closed, momentary switch  221 , wired in series with the electric power source for the vacuum source, is attached to the head stock  205  adjacent to the spring catch  217 , such that, whenever the hood  10  is raised to the storage position adjacent the head stock  205 , the nose panel  70  depresses and opens the momentary switch  221 , thereby de-energizing the vacuum source. The head stock  205  is provided with a removable cap  205 C, whereby, with the cap removed, the intake end of the movable vacuum hose  200  may be withdrawn from the head stock  205  and used to vacuum clean the table saw  18  and its immediate environs, and thereafter replaced inside the head stock  205 .  
         [0056]     The head stock  205  and the attached intake duct  206  may also be rotated about a horizontal axis between a lowered position, shown in  FIGS. 9-15 , and a raised position, as shown in  FIG. 16 . For this purpose, the head stock  205  has a circumferential slot  205 S and a lock mechanism  153  comprising a lock plate  153 P with an upstanding threaded shank that extends through the clot  205 S, and a locking handle  153 K with a threaded recess to receive the threaded shank.  
         [0057]     The side panels  30 , side skirts  120 , upper cowl  80 , lower cowl  90 , and deflector panels  223 , may be made out of any suitably rigid, durable material, but a transparent material, such as polycarbonate or LEXAN® plastic, is preferred. It will be appreciated that various modifications can be made to the exact form of the present invention without departing from the scope thereof. As a first example, the stop means  103  could be attached to the side panels  30  or elsewhere on the hood  10  instead of attached to the side skirts  120 . As a second example, the hood  10  might be pivotally attached by a parallelogram linkage to an overhead boom equipped with a counterbalance mechanism in a manner well known to those having skill in the art, such as is depicted in  FIG. 16 . Accordingly, it is intended that the disclosure be taken as illustrative only and not limiting in scope, and that the scope of the invention be defined by the following claims.

Technology Category: 4