The present invention claims priority on United States Provisional Application Serial Nos. 61 /450,232 filed March 8, 201 1 and 61 /450,225 filed March 8, 201 1 , both of which are incorporated herein by reference.

The present invention is related to cutting devices, particularly directed to hole saws, more particularly directed to a hole saw that includes a plurality of hole saw blades that can be rotated independently of one another, and still more particularly to a hole saw that includes two hole saw blades that can be simultaneously rotated in opposite direction to one another.

BACKGROUND OF THE INVENTION

A hole saw is a common tool that is used to cut a circular opening in a variety of materials (e.g., metal, wood, plastic, composite materials, tile, etc.). A hole saw can include an arbor or mandrel and a saw blade assembly connected with the arbor. The arbor or mandrel typically includes a body with an end portion that engages a hole saw blade to secure the hole saw blade to the arbor or mandrel. The arbor or mandrel can be rotationally driven by a device such as a power drill or the like. Generally, the arbor or mandrel is designed to be inserted in a drill chuck or the like.

Typically the hole saw blade has a cylindrical shape with cutting teeth at one end and a threaded boss at the other for screwing into an arbor or mandrel for rotational operation in a drill. The type of connection arrangement between the hole saw blade and the arbor or mandrel can include other types of connection arrangements.

The arbor or mandrel can also be designed to connect to a drill bit for boring a centering hole. In such an arrangement, a drill bit or pilot drill extends from the center of the arbor or mandrel and through the center of the hole saw blade. The hole saw blade can be designed to be connected to the arbor or mandrel before or after the drill bit or pilot drill is connected to the arbor or mandrel. The drill bit or pilot drill can also be permanently connected to or be releasably connected to the arbor or mandrel. The drill bit or pilot drill, when used, generally protrudes further than the length of the hole saw blade so as to contact the material to be cut prior to contact by the hole saw blade. The hole saw blade can include various types of teeth configurations. Generally, the hole saw blade includes teeth having a uniform size and orientation; however, the teeth can have repetitive groups of different sizes and/or orientation.

Various types of hole saws and hole saw blades are disclosed and illustrated in the following patents and patent applications, all of which are incorporated herein by reference: US

Patent Nos. 8,079,787; 8,052,356; 7,967,535; 7,959,371 ; 7,934,893; D634.343; 7,850,405;

7,824,137; 7,818,867; 7,766,583; 1)620,035; 7,674,078; 7,661 ,913; 7,658,576; 7,658, 136;

7,621,703; 7,556,459; 7,513,718; 0588.1 75; 7,384,222; 7,264,428; 7,246,975; 7,237,984;

7,163,362; 7, 160,064; 1)529,525; 7,1 12,016; 7,104,738; 7, 101 ,124; 7,097,397; D516,594; 7,001,1 16; 6,881 ,017; 6,746,187; 6,705,807; 6,641 ,338; 6,623,220; 0478,919; 0478.339;

1)478, 106; 0478.105; 6,599,063; 6,588,992; 6,409,437; 6,409,436; 6,379,089; 6,341 ,925;

0438,219; 6,065,909; 6,048,141 ; 6,007,279; 5,934,845; 5,904,454; 5,867,913; 5,829,929;

5,820,315; 5,803,678; 5,803,677; 5,800,148; 5,800,099; 5,743,682; D392,297; 0391 ,974;

5,658,102; 5,651,646; 5,435,672; 5,413,437; 5,366,326; 5,352,071 ; 5,292,210; 5,226,762; 5,205,685; 5,108,235; 5,096,341 ; 5,061, 126; 5,035,550; 5,035,548; 5,007,777; 4,968,189;

D303,1 18; 4,760,643; 4,755,088; 4,755.087; 4,741 ,651 ; 4,669,928; 4,579,486; D282,369;

4.422,81 1 ; 4,303,357; 4,279,551 ; 4,203,692; 4,148,593; 4, 101 ,238; 4,077,737: 4,072,441 ;

4,036,560; 3,999,869; 3,976,387; and 3,973,862; and United States Patent Publication Nos.

2012/0009032; 201 1 025593 1 ; 201 1 0243675; 201 1/0217133; 201 1/0170968; 201 1 /0052340; 201 1/0033257; 201 1/0027030; 2010/0322730; 2010/0303567; 2010/0247258; 2010/0239381 ;

2010/0086372; 2010/0080665; 2010/0067995; 2010/0047030; 2010/0034608; 2009/0267236;

2009/0252567; 2009/02241 16; 2009/0214310; 2009/0169317; 2009/0035082; 2008/0267725;

2008/0260480; 2008/0187405; 2008/0050189; 2008/0019785; 2008/0014035; 2008/0008548;

2007/0269280; 2007/0258780; 2007/0231090; 2007/01 10527; 2007/0104548; 2007/0071565; 2007/00591 13; 2007/0036620; 2007/0020056; 2007/0003386; 2006/0285934; 2006/0280569;

2006/0263158; 2006/0263156; 2006/0210366; 2006/0130629; 2005/0220547; 2005/0042048;

2005/0025592; 2004/0247405; 2004/0191015; 2004/017991 1 ; 2004/0161313; 2004/0042861 ;

2004/0016135; 2003/0077138; 2002/0131835; 2002/0122703; 2002/0106254; 2002/0037201 ; and 2002/00281 17. When using a hole saw, the hole saw blade exerts a torque on the user when cutting through materials. Such torque must be countered by the user in order to cut a hole through the material. The constant resistance by the user to such torque can result in fatigue to the user over time. Once the user becomes fatigued, the user must stop use of the hole saw or risk injury to the user, damage to the hole saw and/or damage to the material being cut by the hole saw. Furthermore, during use of the hole saw, the hole saw blade may cause a periodic jerking action when cutting through the material. If the user does not properly counter such periodic jerking action, the user risks injury, damage to the hole saw and/or damage to the material being cut by the hole saw.

In view of the current state of the art of hole saws, there is a need for a hole saw that reduces the torque caused by the hole saw blade during the cutting operation, reduces fatigue to the user when using the hole saw, improves accuracy of the cutting operation through material, and provides for a smoother cuts through the material.

SUMMARY OF THE INVENTION

The present invention is directed to hole saws, particularly to a hole saw that includes a plurality of hole saw blades that can be rotated independently of one another, and more particularly to a hole saw that includes two hole saw blades that can be simultaneously rotated in opposite direction to one another. Prior art hole saws generally include a single hole saw blade that rotates either clockwise or counterclockwise. Hole saws have been developed that include two hole saw blades; however, the two hole saw blades are designed to rotate in the same direction and at the same rate of rotation during the cutting of material. The present invention pertains to the novel concept of including two hole saw blades that can be rotated together in the in the same direction, but at differing rates of rotation, or be rotated in opposite directions from one another during the cutting of material. The present invention contemplates a power tool that is dedicated for use with one or more hole saw blades. The present invention also contemplates an attachment to a power tool (e.g., power drill, etc.) that can be connected to a power tool at one end and to the plurality of hole saw blades at the other end of the attachment. The ability to rotate two hole saw blades at a different rate of rotation and/or in opposite directions from one another during the cutting of material can result in improved cutting of material by the hole saw blades, reduces the torque applied to the user that is caused by the hole saw blades during the cutting operation and thereby reduces fatigue to the user when using the hole saw, improve the speed and/or accuracy of the cutting operation through a material, and/or provides for smoother cuts and less jerk or abrupt cuts when cutting through the material.

In one non-limiting aspect of the present invention, the hole saw blades are caused to rotate in opposite directions (i.e., clockwise and counterclockwise rotations) to one another during the cutting of a material. The speed or rate of rotation of the two hole saw blades when rotating in opposite directions can be the same or different. In one non-limiting aspect of the invention, the speed or rate of rotation of the two hole saw blades, when rotating in opposite directions, can be the same.

In another and/or alternative non-limiting aspect of the present invention, one of the hole saw blades is partially or fully nested in the cavity of another hole saw blade. In one non- limiting embodiment, one of the hole saw blades is partially nested in the cavity of another hole saw blade. In another non-limiting embodiment, one of the hole saw blades is fully nested in the cavity of another hole saw blade. Each of the hole saw blades generally have a eylindrieally shaped housing and a plurality of cutting teeth at the front end of the housing. As can be appreciated, the housing can have a shape other than a cylindrical shape. As can also be appreciated, the front end can include a single cutting tooth or no cutting teeth. The back end of the housing can be open, partially closed or fully closed. An interior cavity is formed by the interior walls of the housing. The cavity also generally has a cylindrical shape; however, this is not required. The back end of the housing can be open, partially closed or fully closed. In one non-limiting arrangement, a first hole saw blade includes a housing having a front end and a cavity and the second hole saw blade includes a housing having a front end. The front end of the first and/or second hole saw blades can include one or more cutting teeth; however, this is not required. The housing of the second saw blade can include a cavity; however, this is not required. In one non-limiting design of this non-limiting arrangement, the cross-section size and shape of the housing of the second hole saw blade is such that at least a portion of the housing of the second hole saw blade can be inserted into the cavity of the housing of the first hole saw blade and rotate within the cavity of the housing of the first hole saw blade. In another non- limiting design of this non-limiting arrangement, the cross-section size and shape of the housing of the second hole saw blade is such that the complete housing of the second hole saw blade can be inserted into the cavity of the housing of the first hole saw blade and rotate within the cavity of the housing of the first hole saw blade. In still another non-limiting design of this non- limiting arrangement, the cross-section size and shape of the housing of the second hole saw blade is such that only a portion of the housing of the second hole saw blade can be inserted into the cavity of the housing of the first hole saw blade and rotate within the cavity of the housing of the first hole saw blade. In yet another non-limiting design of this non-limiting arrangement, the front end of the housing of the second hole saw blade extends outwardly from the front end of the housing of the first hole saw blade when the hole saw is cutting material with the two hole saw blades. In still yet another non-limiting design of this non-limiting arrangement, the front end of the housing of the second hole saw blade is substantially flush or even with the front end of the housing of the first hole saw blade when the hole saw is cutting material with the two hole saw blades. In still another non-limiting design of this non-limiting arrangement, the front end of the housing of the second hole saw blade is recessed or positioned inwardly from the front end of the housing of the first hole saw blade when the hole saw is cutting material with the two hole saw blades.

In still another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting teeth on the first and second hole saw blades can be the same or different. In one non-limiting embodiment of the invention, the teeth configuration on each of the hole saw blades is the same. In another non-limiting embodiment of the invention, the teeth configuration on each of the hole saw blades is different. In still another non-limiting embodiment of the invention, the teeth on the inner hole saw blade has a tooth configuration where the ends of one or more of the teeth angle inwardly toward the central rotational axis of the hole saw blades. Such a tooth configuration results in the cut material that enters into the cavity of the inner hole saw blade that has a diameter that is less than the diameter of all or a portion of the cavity of the inner hole saw blade. Such diameter has the advantage of a) enabling the inner hole saw blade to continue rotating and cutting the material with reduced friction between the inner surface of the cavity of the inner hole saw blade and the material that is positioned in the cavity as the hole saw cuts through a material, b) increases the ease of cutting through a material, and/or c) makes it easier to remove material from the cavity of the inner hole saw blade. In yet another non-limiting embodiment of the invention, the teeth on the outer hole saw blade has a tooth configuration where the ends of one or more of the teeth angle outwardly from the central rotational axis of the hole saw blades. Such a tooth configuration results in a hole being cut through material having a diameter that is greater than the outer diameter of the housing of the outer hole saw blade. Such diameter of the hole of the cut material has the advantage of a) enabling the outer hole saw blade to continue rotating and cutting the material with reduced friction between the outer surface of the housing of the outer hole saw blade and the hole that has been cut in the material, b) increases the ease of cutting through a material, and/or c) makes it easier to remove the hole saw blades from the hole cut in the material. The configuration of the teeth of the inner and/or outer hole saw blades are non-limiting.

In yet another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that an outer hole saw blade having a generally circular cross-section shape is used and the inner blade that i at least partially positioned in the cavity of the outer hole saw blade is a spade-style counter rotating wood bit; however, this is not required. Such a configuration could be used to reduce or eliminate the cut material plug after drilling the hole in the material.

In still yet another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that the first and second hole saw blades have different diameters to create donut shaped parts holes in the cut material; however, this is not required.

In another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that the first and second hole saw blades have differing blade thickness to facilitate in balancing the counter rotating forces of the two hole saw blades; however, this is not required.

In still another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that the first and second hole saw blades have differing numbers of teeth to facilitate in balancing the counter rotating forces of the two hole saw blades; however, this is not required.

In yet another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that the first and second hole saw blades have differently configured teeth to facilitate in balancing the counter rotating forces of the two hole saw blades; however, this is not required.

In still yet another and/or alternative non-limiting aspect of the present invention, the configuration of the cutting elements of the hole saw can be selected such that the outer hole saw blade can include cutting flutes that can be used to smooth the bore of the cut hole in the material, thus functioning similarly to a reamer to accurately size the cut hole; however, this is not required.

In another and/or alternative non-limiting aspect of the present invention, a pin arrangement can be used that pokes through one or more openings in the back ends of the hole saw blades so as to facilitate in the ejection of the cut plug of material from the hole saw blades; however, this is not required. The pin arrangement could be designed to be spring loaded or biased in some other manner to facilitate in the ejecting of the cut plug from the cavity of the inner hole saw blade; however, this is not required.

In still another and/or alternative non-limiting aspect of the present invention, the power tool is a dedicated tool for use with one or more hole saw blades. Generally, the housing of the power tool is similar to a power drill; however, this is not required. The power tool can be battery powered and/or powered by an AC power cord. The power tool includes a connector that enables one or two hole saw blades to be connected to the power tool. In one non-limiting embodiment, when two hole saw blades are connected to the power tool, the power tool includes gearing that enables the two hole saw blades to be rotated in opposite directions; however, this is not required. The power tool can include gearing that enables the two hole saw blades to be rotated in opposite directions and the same or different rotations per minute (rpm). Generally, the gearing that enables the two hole saw blades to be rotated in opposite directions is partially or fully located in the housing of the power tool. In another and/or alternative non-limiting embodiment of the invention, the power tool can include one or more optional features such as, but not limited to, a "continuous on" button, a button to activate a light or laser, a level indicator, a speed controller, a "lock off button, a torque adjustment, battery powered motor, rechargeable battery, removable battery, vibration reducing hand grip, reduced slip hand grip, tiltable handle, rotatable handle, a hole saw blade quick connect and/or quick release, etc.; however, this is not required.

In yet another and/or alternative non-limiting aspect of the present invention, there is provided a hole saw gear attachment that is designed to enable one end to be connected to a power tool such as a power drill and the other end to be connected to one or two hole saw blades. In one non-limiting embodiment, when two hole saw blades are connected to the hole saw gear attachment, the hole saw gear attachment includes gearing that enables the two hole saw blades to be rotated in opposite directions; however, this is not required. The hole saw gear attachment can include gearing that enables the two hole saw blades to be rotated in opposite directions and the same or different rotations per minute (rpm). Generally, the gearing that enables the two hole saw blades to be rotated in opposite directions is partially or fully located in the housing o the hole saw gear attachment. In another and/or alternative non-limiting embodiment of the invention, the hole saw gear attachment includes a connection arrangement that connects the housing of the hole saw gear attachment to the body of the power tool. Such a connection arrangement transfers torque caused by the gearing that is partially or fully in the housing of the hole saw gear attachment to be transferred to the body of the power tool so as to prevent the housing of the hole saw gear attachment to rotate relative to the body of the power tool; however, this is not required. Such an arrangement can be used so that a torque limiting handle can be eliminated from the body of the hole saw gear attachment. When the connection arrangement is not used, a handle generally is connected to the body of the hole saw gear attachment so that a user can grasp the handle to prevent the housing of the hole saw gear attachment from rotating as the hole saw cuts through material; however, this is not required. As can be appreciated, a handle can still be connected to the housing of the hole saw gear attachment when a connection arrangement is used; however, such a handle is generally then used to better grasp the power tool and hole saw gear attachment and/or to facilitate in directing the one or more hole saw blades into a material during the cutting of material. The type and/or configuration of the connection arrangement are non-limiting. The location that the connection arrangement is connected to the housing of the hole saw gear attachment and/or body of the power tool is non-limiting. As can be appreciated, the connection arrangement is generally not connected to the rotating portions of the power tool.

In still yet another and/or alternative non-limiting aspect of the present invention, a center drill bit can be optionally used with the one or more hole saw blades. The center drill bit, when used, can be used to start a center hole in the material that can be used to orient and position the one or more hole saw blades as the material is being cut. The center drill bit can be connected to one or more of the hole saw blades, the power tool, arbor or mandrel, etc. The type of connection used is non-limiting.

In another and/or alternative non-limiting aspect of the present invention, the housing of one or more of the hole saw blades can include one or more openings; however, this is not required. The size and shape of the one or more openings are non-limiting. The one or more openings in the one or more hole saw blades can be used to 1) facilitate in removing material from the housing cavity of one or more hole saw blades, and/or 2) facilitate in the cutting of material by the hole saw blades.

The hole saw of the present invention can have one or more of the following functions and/or features:

The hole saw includes a counter-rotational spinning mechanism which allows a set of nested hole saw blades to rotate in opposite cutting directions.

The hole saw can be a dedicated power tool for use with one or more hole saw blades, or be a tool attachment that can be connected/disconnected from a power tool (e.g., power drill, etc.) and which tool attachment includes a counter-rotational spinning mechanism which allows a set of nested hole saw blades to be connected to the tool attachment and be rotated in opposite cutting directions.

The hole saw can be designed to enable a user to attach or remove one or more hole saw blades from the saw chuck.

The hole saw and/or hole saw blades can be made from a variety of materials, including but not limited to, metal, plastic, aluminum or recyclable material. The hole saw can be designed for use with two tightly nested hole saw blades designed to individually rotate in opposing directions.

The hole saw blades can include teeth that will allow the cutting action to be performed in both rotating directions.

· The hole saw blades can be created for custom use on or with a variety of materials.

• The hole saw blades can be designed for specific cutting purposes.

The inner and outer diameters of the inner hole saw blade and the outer hole saw blade can be tight enough to allow for easy cutting, yet have enough space between the two hole saw blades to reduce heat and friction f the hole saw blades against each other.

The use of two hole saw blades that rotate in opposite directions can be used to oppose the cutting force with each other, and thereby balance the cutting action of the power tool.

The hole saw can be designed to improve accuracy, to provide smoother cuts on work surfaces, and to reduce fatigue on the user during use of the hole saw.

• The hole saw can be designed for use with one or two hole saw blades.

Various styles of hole saw blades can be designed for specific cutting purposes.

• The hole saw can be designed to enable a user to attach or remove the hole saw- blades from the blade holders.

· The hole saw can be designed to include a rotating handle.

The hole saw can be designed to include a pivoting handle.

The hole saw can be designed to be a handheld tool.

• The hole saw can be designed to include one or more electric motors.

• The hole saw can be designed to include one or more hole saw blades that include a generally repeating V-shape teeth, W-shape teeth, alternating V-shape and W-shaped teeth, etc.

The hole saw can be designed to include one or more hole saw blades that include diamond cutting edges (i.e., diamond grit blades).

The hole saw can be designed to include one or more hole saw blades that have blade teeth on one or both sides of one or both hole saw blades. The hole saw can be designed to include one or more hole saw blades that have blade teeth and wherein every other tooth is angled outwardly.

• The hole saw can be designed to include one or more hole saw blades that have blade teeth and wherein one or more teeth are both angled and tapered.

• The hole saw can be designed to include one or more hole saw blades that include one or more blade separators to maintain the spacing of the hole saw blades from one another during the operation of the hole saw blades.

• The hole saw can include two hole saw blades wherein the outer hole saw blade has a generally circular cross-section shape and the inner blade that is at least partially positioned in the cavity of the outer hole saw blade is a spade-style counter rotating wood bit so as to reduce or eliminate the cut material plug after drilling the hole in the material.

The hole saw can include two hole saw blades wherein the first and second hole saw blades have different diameters to create donut-shaped parts holes in the cut material; however, this is not required.

• The hole saw can include two hole saw blades wherein the first and second hole saw blades have differing blade thicknesses to facilitate in balancing the counter-rotating forces of the two hole saw blades.

• The hole saw can include two hole saw blades wherein the first and second hole saw blades have di fering numbers of teeth to facilitate in balancing the counter rotating forces of the two hole saw blades.

• The hole saw can include two hole saw blades wherein the first and second hole saw blades have differently configured teeth to facilitate in balancing the counter-rotating forces of the two hole saw blades.

The hole saw can include two hole saw blades wherein the outer hole saw blade can include cutting flutes that can be used to smooth the bore of the cut hole in the material, thus functioning similarly to a reamer to accurately size the cut hole.

The hole saw can include a pin arrangement that can be used to poke through one or more openings in the back ends of the hole saw blades so as to facilitate in the ejection of the cut plug of material from the hole saw blades. The hole saw can include two hole saw blades wherein a center drill bit can be used with the one or more hole saw blades.

The hole saw can include two hole saw blades wherein the housing of one or more of the hole saw blades can include one or more openings to 1 ) facilitate in removing material from the housing cavity of one or more hole saw blades, and/or 2) facilitate in the cutting of material by the hole saw blades.

It is one non-limiting object of the present invention to provide a multi-blade hole saw. It is another and/or alternative non-limiting object of the present invention to provide a multi-blade hole saw wherein two or more hole saw blades rotate in the opposite direction from one another and/or rotate at the same or different rates of rotation from one another.

It is still another and or alternative non-limiting object of the present invention to provide a power tool that is dedicated to the use with one or more hole saw blades.

It is yet another and/or alternative non-limiting object of the present invention to provide a hole saw gear attachment that is designed to enable one end to be connected to a power tool such as a power drill and the other end to be connected to one or two hole saw blades.

It is still yet another and/or alternative non-limiting object of the present invention to provide a hole saw gear attachment that includes a connection arrangement that connects the housin of the hole saw gear attachment to the body of the power tool.

It is still yet another and/or alternative non-limiting object of the present invention to provide a hole saw arrangement that includes the use of two hole saw blades and wherein the configuration of the cutting teeth on the first and second hole saw blades is different.

These and other objects and advantages will become apparent to those skilled in the art upon reading and following the description taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference may now be made to the drawings which illustrate various preferred embodiments that the invention may take in physical form and in certain parts and arrangement of parts wherein:

FIGURE 1 is a side elevation view of the hole saw gear attachment that includes two hole saw blades in accordance with the present invention; FIGURE 2 is a side view of the hole saw gear attachment of FIGURE 1 ;

FIGURE 3 is a bottom plan view of the hole saw gear attachment of FIGURE 1 ;

FIGURE 4 is a top plan view of the hole saw gear attachment of FIGURE 1 ;

FIGURE 5 is a back end view of the hole saw gear attachment of FIGURE 1 ;

FIGURE 6 is a front end view of the hole saw gear attachment of FIGURE 1 ;

FIGURE 7 is a cross-section view of the hole saw gear attachment of FIGURE I ;

FIGURE 8 is a side elevation view of the hole saw gear attachment without the two hole saw blades;

FIGURE 9 is an exploded view of the hole saw gear attachment of FIGU E 1 ;

FIGURE 10 is a side elevation view of the hole saw gear attachment of FIGURE 1 without the housing;

FIGURE 1 1 is a side elevation view of the hole saw gear attachment of FIGURE 1 without the housing and the two hole saw blades; and,

FIGURE 12 is a side elevation view f the hole saw gear attachment of FIGURE 1 that is connected to a power tool and includes a handle connected to the housing of the hole saw gear attachment.

DETAILED DESCRIPTION OF NON-LIMITING EMBODIMENTS

Referring now to the drawings wherein the showings are for the purpose of illustrating one non-limiting embodiment f the invention only and not for the purpose of limiting same. FIGURES 1 - 12 illustrate non-limiting embodiments of the hole saw in accordance with the present invention.

Referring to FIGURE 1, there is a hole saw gear attachment 100 that is designed to be connected to a power tool such as a power drill 600 as illustrated in FIGURE 12.

The hole saw gear attachment 100 includes a housing 1 10. Positioned within the housing is a gearing arrangement that is designed to cause the first hole saw blade 400 and the second hole saw blade 500 to simultaneously rotate in opposite directions from one another when cutting material. The two hole saw blades are illustrated as positioned at the front end 120 of the housing. An arbor or drive shaft 210 extends outwardly from the back end 140 of the housing. The arbor 210 is designed to provide a connection between the power drill 600 and the housing of hole saw gear attachment 100. The materials used to form the hole saw gear attachment are non-limiting. Generally, the materials are durable materials such as metal, plastic, composite materials, etc. The housing 1 10 is illustrated as having a generally cubical shape; however, this is not required. The housing can have any shape (e.g., cylindrical, conical, etc.).

Referring now to FIGURES 1 , 7 and 9, the first hole saw blade 400 and the second hole saw blade 500 each have a housing 410, 510 that has a generally cylindrical shape. As can be appreciated, the shape of the housings of the two hole saw blades can have different shapes. As can also be appreciated, the shape of the housings of the two hole saw blades can be the same or different. The material used to form one or both hole saw blades is non-limiting (e.g., metal, composite materials, ceramic, plastic, etc.) One or more hole saw blades can include diamond cutting edges (i.e., diamond grit blades); however, this is not required. The hole saw blades can be formed of the same or different materials. As best illustrated in FIGURE 1 , the outer diameter of housing 5 10 is less than the inner diameter of cavity 420 in housing 410 so that housing 5 10 of the second hole saw blade can be teleseopically received in cav ity 420 of housing 410. The si/.e and shape of housing 510 are generally selected so that when housing 10 of the second hole saw blade is partially or fully positioned in cavity 420 of housing 410, the two hole saw blades are able to be rotated relative to one another. As illustrated in FIGURE 7, most of the outer surface of housing 510 is spaced from the inner wall of cavity 420. As also illustrated in FIGURE 7, the teeth 430, 530 on the two hole saw blades are positioned closely adjacent to one another; however, this is not required. In such an arrangement, the teeth of the two saw blades are in contact with one another or are positioned closer together than the outer surface of housing 510 and the inner wall of cavity 420; however, this is not required. Such a spacing arrangement can be used to inhibit or prevent cut material from entering the space between the outer surface of housing 510 and the inner wall of cavity 420; however, this is not required.

The side of the housing of one or both of the hole saw blades can optionally include one or more openings 440, 540. The openings can be used to 1) enable cut material that is positioned in the space between the outer surface of housing 510 and the inner wall of cavity 420 to move from the space, 2) enable one or both hole saw blades to be grasped when inserting and/or remove one or both hole saw blades on/from the hole saw gear attachment, 3) aligning the hole saw blades when inserting and/or removing one or both hole saw blades on/from the hole saw gear attachment, and/or 4) facilitating in removing material in the cavity 420 and/or cavity 520, As can be appreciated, the one or more openings can have other or additional uses and functions.

The tooth configuration on the two hole saw blades can be the same or different. As illustrated in FIGURE 6, the tooth configuration on the two hole saw blades is different. The tooth configuration of teeth 530 illustrates that some of the teeth 532 extend generally parallel with the central rotational axis of the hole saw blades and some of the teeth 534 angle inwardly toward the central rotational axis of the hole saw blades. The tooth configuration of teeth 430 illustrates that some f the teeth 4 2 extend generally parallel with the central rotational axis of the hole saw blades and some f the teeth 434 angle outwardly from the central rotational axis of the hole saw blades. The angle of teeth 434, 534 can be selected to facilitate in 1) the cutting of material by the hole saw blades, 2) the removal of the hole saw blades from a cut material, and/or 3) the removal of material from cavity 420 and/or cav ity 520. As can be appreciated, the tooth configuration on one or both hole saw blades can have other or additional advantages and functions. Non-limiting tooth configurations and materials used to form the hole saw blades are illustrated in one or more patents and patent applications that have been incorporated herein by reference. As illustrated in FIGURES 2-4 and 7, the front ends of the teeth of the two hole saw blades is substantially Hush with one another; however, this is not required. As illustrated in FIGURE 7, the second hole saw blade is fully or substantially fully positioned in the cavity of the first hole saw blade; however, this is not required.

Referring now to FIGURES 7 and 9-1 1 , there is illustrated one non-limiting arrangement that can be used to cause the two hole saw blades to rotate in opposite directions during the cutting of material. As illustrated in FIGURE 7, housing 1 10 of hole saw gear attachment 100 is formed of four pieces, namely a main housing 120, a top housing plate 130, a rear housing plate 140 and a front housing plate 150. The top housing plate 130 is connected to the main housing 120 by a plurality of screws 132 that are inserted through openings 134 in the top housing plate and engage screw openings 122 in the main housing. Screws 142, 152 are used to connect the rear and front housing plates to the main housing by inserting the screws through openings 144, 154 and connecting the screws to screw openings 122 in the main housing. The configuration of housing 1 10 is non-limiting. The housing can be formed of less than four pieces or be formed of more than four pieces. The one or more housing plates, when used, can be connected to the other pieces of the housing in other or additional ways (e.g., rivet, pin, adhesive, weld bead, melted seam, snap lock connection, etc.). One or more components of the housing can be formed by injection molding; however, this is not required.

The gear arrangement 200 that is partially or fully housed in housing 1 10 includes a novel gearing arrangement that is used to cause the two hole saw blades to rotate in opposite directions during the cutting of material. The gear arrangement includes an arbor 210. The arbor 210 has a rear section 214 that is designed to be connected to a power tool. As defined herein, the term "power tool" includes a tool that can provide a rotational force for rotating the arbor. Such rotational force can be achieved by using electro-motive force, user-generated force, etc. In one non-limiting arrangement, the power tool can be a conventional electric 600 or user- operated drill. The power tool generally includes a tool-bit holder 610 that is capable of securing and holding rotating tools and/or materials. In one non-limiting arrangement, the tool-bit holder can include a quick release chuck. The chuck, when used, can be a self-centering, independent- j w, multi-jaw, collet, Special Direct System (SDS), magnetic, electrostatic, or vacuum chuck. The rear section 214 of arbor 210 can have a hexagon configuration; however, this is not required. The ability to connect and disconnect a tool from a standard chuck on a power tool is known in the art and the configuration of chucks used on conventional power tools is known in the art, thus no further discussion of the chuck configuration and the connection and disconnection of the rear section 214 of arbor 210 to/from the tool-bit holder 610 of the power tool will not be discussed herein.

The arbor 210 includes a flange 220 on the body of the arbor that connects to a first bushing 240 by screws 222. The first end of the arbor extends through opening 146 in the rear housing plate 144. The first bushing is designed to facilitate in the centering of the arbor along the central rotational axis of the hole saw blades and to facilitate in the proper alignment and rotation of the arbor relative to housing 1 10. A first primary gear 240 is connected to the bushing by screws 232. A gear bearing 250 is positioned between the first primary gear and the second primary gear 260. A gear connector 270 and a second bushing 280 are used to secure the second primary gear 260 to the second bushing 280. Screws 290 can be used to secure the second bushing to the second primary gear. A centering ring 300 can be used to center the bushing in opening 1 56 of the front housing plate.

The front section 212 of arbor 210 is designed to extend though first bushing 230, first primary gear 240, gear spacer 250, a second primary gear 260, a gear bearing 270, the second bushing 280, the centering ring 300, and opening 156 of the front housing plate; however, this is not required. The gear arrangement is such that the first primary gear is connected such that the first primary gear rotates in the same direction as the arbor and the second primary gear rotates in the opposite direction of the arbor. The opposite rotation direction of the second gear is accomplished by first and second secondary gears 310, 320. As illustrated in FIGURES 10 and 1 1 , first secondary gear 310 is designed to engage first primary gear 240, but not second primary gear 260, and second secondary gear is designed to engage second primary gear 260, but not first primary gear 240. The two secondary gears are also designed to engage one another. The arrangement of the secondary gears results in the two primary gears to rotate in opposite directions. For example, when the arbor is rotated by the power tool in the clockwise direction, first primary gear 240 also is caused to rotate in the clockwise direction since the first primary gear is connected to first bushing 230, which is connected to flange 220, which is connected to the arbor. The clockwise rotation of the first primary gear causes the first secondary gear 310 to rotate in a counter-clockwise direction. The rotation of the first secondary gear 3 10 in the counter-clockwise direction causes the second secondary gear 320 to rotate in the clockwise direction. The rotation of the second secondary gear 320 in the clockwise direction causes the second primary gear to rotate in the counter-clockwise direction. Since the second primary gear is not connected to the body of the arbor, the second primary gear can be caused to rotate in the opposite direction of the first primary gear via secondary gears 310, 320. Secondary gears 310, 320 are supported in position by rods 330, 340 and ring locks 350, 360. As can be appreciated, the gear arrangement described above is just one of many gear arrangements that can be used to enable the first and second hole saw blades to rotate in opposite directions to one another.

Referring now to FIGURE 7, the first saw hole blade 400 is connected to a front portion 282 of the second bushing 280. The front portion 282 can include a threaded surface to enable a front flange portion 450 to be threadedly connected to the second bushing. As can be appreciated, the first hole saw blade can be connected to the second bushing and/or other components of the gear arrangement in other or additional ways (e.g., screws, pins, etc.). As is illustrated in FIGURE 7, the flange portion 450 and the back wall 460 of the first hole saw blade 400 include an opening that enables the front section 212 of the arbor to extend through the flange portion and back wall; however, this is not required. The connection of the first saw hole blade to the second bushing results in the first hole saw blade to rotate about the central rotational axis of the hole saw blades in the opposite direction of rotation of the arbor. As illustrated in FIGURE 7, the central axis of the arbor lies in or substantially in the central rotational axis of the hole saw blades.

The second hole saw blade is connected to a blade connector 370. The blade connector includes a flange 372 that is designed to be connected to the front end of the arbor 210 as illustrated in FIGURE 7. The front end of the arbor can include a threaded connection cavity that enables flange 372 to be threadedly connected to the arbor. As can be appreciated, other or additional connection arrangements can be used to connect the blade connector to the arbor or other components of the gear arrangement. Screws 374 are used to secure the second hole saw blade to the blade connector. The screws are designed to be inserted through holes 372 in the blade connector and to engage screw openings 552 in the back wall 550 of the second hole saw blade. As can be appreciated, other or additional connection arrangements can be used to connect the second hole saw blade to the blade connector and/or arbor and/or other components of the gear arrangement. The connections of the second hole saw blade to the blade connector, which is connected to the arbor, results in the second hole saw blade to rotate in the same direction as the arbor. As illustrated in FIGURE 7, the back wall 550 of the second hole saw blade is spaced from the inner surface of the back wall 460 of the first hole saw blade; however, this is not required. Such spacing can be used to reduce friction between the first and second hole saw blades as the two blades rotate in opposite directions during the cutting of material.

As can be appreciated, the hole saw gear attachment 100 can be used with only the first or second hole saw blade if such an arrangement is desired. As illustrated in FIGURE 7, the blade connector 370 can optionally include a bit opening 376 that is designed to receive a centering drill bit 380. The front end of the drill bit extends outwardly and beyond the front edge of the teeth of the first and second hole saw blades; however, this is not required. The use of the centering drill bit is optional. The centering drill bit can be connected to the blade connector by a threaded connection or some other type of connection.

As can be appreciated, the hole saw gear attachment 100 can be fully integrated into the body of a power tool to create a power tool dedicated to be used with one or more hole saw blades.

Referring now to FIGURE 12, the hole saw gear attachment 100 can optionally include one or more handles 390 that can be connected to housing 1 10. The handle can be used to facilitate in the handling of the power tool when used with the hole saw gear attachment 1 0. The handle can also be used to counter torque resulting from the use of the hole saw gear attachment on the power tool. The type of handle and location of the handle on the housing of the hole saw gear attachment is non-limiting.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained, and since certain changes may be made in the constructions set forth without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. The invention has been described with reference to preferred and alternate embodiments. Modifications and alterations will become apparent to those skilled in the art upon reading and understanding the detailed discussion of the invention provided herein. This invention is intended to include all such modifications and alterations insofar as they come within the scope of the present invention. It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention, which, as a matter of language, might be said to fall therebetween. The invention has been described with reference to the preferred embodiments. These and other modifications of the preferred embodiments as well as other embodiments of the invention will be obvious from the disclosure herein, whereby the foregoing deseriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims.