WO2009021278A1

WO2009021278A1 - A tool

Info

Publication number: WO2009021278A1
Application number: PCT/AU2008/001162
Authority: WO
Inventors: Bradford Watt
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-08-10
Filing date: 2008-08-11
Publication date: 2009-02-19
Anticipated expiration: 2010-02-10

Abstract

A hole saw having a saw body having a base end with a longitudinal aperture therethrough, a side wall extending from said base end and defining an interior cavity and an outer edge, and a plurality of cutting teeth formed on said outer edge; and a mandrel configured to be coupled to a source of rotational power; a saw body attachment portion mounted for rotation relative to the mandrel and a locking mechanism adapted to releasably lock the rotation of the saw body attachment portion to the mandrel, the locking mechanism having an engaged condition and a free condition wherein movement of the locking mechanism to the engaged condition releasably locks the rotation of the saw body attachment portion to the mandrel and movement of the locking mechanism to the free condition disengages the rotation of the saw body attachment portion from the mandrel, allowing independent rotation of the saw body attachment portion and the mandrel.

Description

A TOOL Field of the Invention.

The present invention relates to tools and particularly to tools used by tradesmen and labourers which are typically carried on their person. Background Art.

Hole saws in general are known.

For example, a typical hole saw consists of a cylindrical saw body that forms a heavy base end with a threaded axially aligned hole in the bore. A threaded mandrel is adapted to screw into the base of the hole saw body from the outside or base end of the saw. The mandrel at its threaded end forms a hole to accept the shank of a drill, the opposite end of the mandrel forming a shank designed to be received by the chuck of a drill motor or the like. Intermediate the threaded end and the shank of the mandrel is a flange formed typically in a round or hex-nut shape for securing the mandrel in the base of the hole saw. A slotted screw on the flange secures the shank of the pilot drill positioned in the hole formed in the threaded end of the mandrel.

A right-hand thread is normally used to secure the mandrel and the hole saw body. In use then, when the serrated end of the saw contacts the surface of the material to be sawn, a reactive force between the hole saw body and the mandrel tightens the mandrel against the saw body allowing it to cut. Another well known hole saw utilizes a slightly different configuration.

The single mandrel for the various diameter hole saws consists of a mandrel body having a first flanged base end and a second, smaller— diameter, threaded end— the mandrel further forming an axially aligned hole therethrough adapted to accept a drill bit. The shank of the drill bit has flats to accept a slotted screw retained in the mandrel flange to secure the drill in the mandrel. The shank end of the drill is used to secure the hole saw in a drill motor as heretofore described. The flange of the mandrel is stepped down in diameter, forming a circular shoulder at its base, the intermediate flange being formed with flats that conform to complimentary flats formed in the base of the hole saw. The drill-containing mandrel then is inserted through the open serrated end of the hole saw, the intermediate flange flats being aligned with the flats of the hole saw to prevent rotation of the mandrel with respect to the hole saw. A threaded nut then is slipped over the shank of the drill and tightened into the threaded end of the mandrel protruding through the base of the hole saw, thereby securing the hole saw between the mandrel and the nut.

One of the problems associated with using the hole saws with threaded attachments between the mandrel and hole saw body is that the thread tends to tighten during use of the saw often to the point where the application of sufficient force to disengage the mandrel from the saw body can only be realized using a vice or similar.

The present invention in its second embodiment relates generally to tool commonly referred to as a "carpenter's level". A carpenter's level may be used to determine the angular position of a given plane or surface relative to a reference plane or surface. A carpenter's level generally includes a level bubble mounted in a housing. The level bubble is mounted in the housing at a predetermined orientation relative to a reference edge of the housing. As a result, the angular position of a surface may be determined by placing the reference edge of the housing against the surface.

Adjustable length levels and collapsible squares are well known in the art. Many extendable levels have a levelling means in their main or central body but when the extenders are in a collapsed position the levelling bubble cannot be seen conveniently.

For example, U.S. Pat. No. 4,130,943 describes an extension level which can be extended in 6 inch increments. This patented level can no more than double its length when fully extended. Its levelling means is in the central body and the level can not be locked in any extended position.

U.S. Pat. No. 4,152,838 discloses a level with a sliding scale. The subject level can no more than double its collapsed length, does not have a contiguous level plane bottom surface when extended, has a levelling means in the central body and is not lockable in any extended position. U.S. Pat. No. 4,733,475 describes an extension level with a spring loaded device to allow the level to be retained in a wall opening. It is very complicated with many parts and would be expensive to construct. Components of this invention could not be extruded, hence, manufacturing costs are excessive.

U.S. Pat. No. 4,894,925, discloses an extension level in which the extender rests within the main body. This invention can no more than double its collapsed length when fully extended, holds a levelling means in its main body, and is not lockable in any extended position.

U.S. Pat. No. 4,928,395 discloses an extendable level which has two extensions which are slidable within a two piece main body. This level can not more than double its length in its fully extended position, does not have a contiguous level plane bottom surface when extended, and is not lockable in any extended position.

U.S. Pat. No. 4,910,876 discloses a level attachment arm which forms a square with one I beam shaped level. U.S. Pat. No. 5,249,365 discloses a level with telescoping sleeve extenders. This level does not provide a contiguous level plane bottom edge surface when extended, nor is it lockable in any extended position.

U.S. Pat. No. 5,412,875 discloses an extension level with at least one levelling vial mounted within the main frame and an elongated arm fabricated of transparent material. This invention can no more than double its length when fully extended, has a levelling means in its main body, is not lockable in any extended length, and parts can not be extruded.

U.S. Pat. No. 5,617,641 describing an adjustable length level incorporating rods as extenders. The level described in this patent does not have a desired contiguous plane bottom edge surface, is not lockable in any extended position, and main body members can not be extruded.

Square adapters for levels are also known. These tools are typically attachments which are added to the level in order to form a 90° angle.. However, most of these previously known forms of adapters require specially constructed squares and do not include positive structure whereby the square adapter may be accurately secured in a square defining position relative to the associated level body.

Various forms of square adapters for levels including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 973,437, 1,324,411, 1,646,958 and 1,663,821. Accordingly, a need exists for a carpenter's level constructed in a manner whereby the level is adjustable in at least length and including a square adapter which may be accurately positioned relative to the carpenter level to define a carpenter's square.

It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

Summary of the Invention. The present invention is directed to a hole saw, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

With the foregoing in view, the present invention in one form, resides broadly in a hole saw having a saw body having a base end with a longitudinal aperture therethrough, a side wall extending from said base end and defining an interior cavity and an outer edge, and a plurality of cutting teeth formed on said outer edge; and a mandrel configured to be coupled to a source of rotational power; a pilot drill bit adapted for rotation with the mandrel; and a locking mechanism to releasably lock the saw body relative to the mandrel having an engaged condition and a free condition wherein movement of the locking mechanism to the engaged condition releasably locks the saw body to the mandrel and movement of the locking mechanism to the free condition disengages the saw body from the mandrel.

According to a further aspect, the invention resides in a hole saw having a saw body having a base end with a longitudinal aperture therethrough, a side wall extending from said base end and defining an interior cavity and an outer edge, and a plurality of cutting teeth formed on said outer edge; and a mandrel configured to be coupled to a source of rotational power; a saw body attachment portion mounted for rotation relative to the mandrel and a locking mechanism adapted to releasably lock the rotation of the saw body attachment portion to the mandrel, the locking mechanism having an engaged condition and a free condition wherein movement of the locking mechanism to the engaged condition releasably locks the rotation of the saw body attachment portion to the mandrel and movement of the locking mechanism to the free condition disengages the rotation of the saw body attachment portion from the mandrel, allowing independent rotation of the saw body attachment portion and the mandrel.

According to still a further aspect, the invention resides in a hole saw including a. a saw body having i. a base end with a longitudinal aperture therethrough and at least one transverse opening intersecting the longitudinal aperture, ii. a side wall extending from said base end and defining an interior cavity and an outer edge, and iii. a plurality of cutting teeth formed on said outer edge; and b. a mandrel having i. a first end configured to be coupled to a source of rotational power ii. a second end supporting an outwardly extending flange; iii. a side wall extending from said outwardly extending flange having an outer edge and defining an interior cavity; c. a pilot drill bit adapted for rotation with the first end of the mandrel and having a shank and a cutting portion with at least one shaped portion of reduced dimension located on the shank; and d. a locking mechanism to releasably lock the saw body relative to the mandrel, the locking mechanism including i. a saw body attachment portion with a longitudinal opening therethrough to receive the pilot drill bit, at least one transverse opening intersecting the longitudinal opening, at least one locking member seated at least partially in the transverse opening and movable between an engaged condition in which the locking member is forced outwardly to engage the at least one transverse opening in the saw body to releasably lock the saw body to the mandrel and a free condition in which the locking member is disengaged from the at least one transverse opening in the saw body allowing removal of the saw body from the mandrel; ii. a lock member having a longitudinal opening therethrough to receive the pilot drill bit, and at least one locking portion to releasably lock rotation of the lock member relative to the saw body attachment portion and movable between an engaged condition in which the rotation is locked and a free condition where the lock member can be rotated independently of the saw body attachment portion; wherein movement of the lock member to the engaged condition also moves the at least one locking member to the engaged condition to releasably lock the saw body to the mandrel and movement of the lock member to the free condition also moves the at least one locking member to the free condition to disengage the saw body from the mandrel.

The present invention is adapted to allow a quick and easy but still secure mechanism for the attachment of a saw body to a mandrel. The tool of the present invention will typically be used in combination with a power drill as the source of the rotational power. The hole saw is normally used to form a larger diameter opening than a conventional drill bit. Hole saws are particularly used in fitting door knobs and lock assemblies to doors but may be used for other purposes such as the formation of openings for conduits for example.

The hole saw of the present invention will typically be mounted for rotation about a central longitudinal axis. All of the main components of the hole saw will typically be substantially circular in cross-section in order to rotate efficiently and minimise vibration and the like. Where possible, the position of the components of the hole saw of the invention will normally be described relative to each other along the longitudinal axis.

Normally all of the components of the hole saw of the present invention are manufactured of metal given the potentially large torsional loads that will be borne by the tool during use. The saw body provided in the hole saw of the present invention is generally cylindrical with an open end located opposite the base end. The base end of the saw body will typically be of greater thickness than the sidewall of the saw body.

The aperture in the base end will normally be substantially centrally located in order to mount the saw body for rotation. That is, the aperture will typically be formed along the longitudinal axis of the tool. The aperture will normally be a shaped opening, in order to positively locate and/or engage the saw body relative to the mandrel. Preferably, the shape of the aperture will also provide an element of self- location for the saw body during attachment to the mandrel. It is particularly preferred that the aperture be shaped having a pair of parallel sides linked by a pair of arcuate ends. This will prevent a circular member being inserted and the parallel sides provide a positive contact surface.

There will also preferably be at least one transverse opening provided in the base end of the saw body. The at least one transverse opening will typically extend through the base end perpendicularly to the longitudinal aperture and axis of rotation. The transverse opening preferably intersects the longitudinal aperture.

The transverse opening is preferably sized according to a part of the locking mechanism to receive at least a portion of the locking mechanism therein to releasably lock the saw body relative to the mandrel. The transverse opening may be of any shape but as it will normally be formed by drilling, the cross-sectional shape will normally be circular.

There may further be one or more cut-out portions in or through the side wall of the saw body to allow or facilitate removal of the plug formed when the saw is used, namely that removed from the material through which the saw cuts.

The lower or outer surface of the base end is preferably a planar surface. There may be additional openings into or through the outer surface of the base end to assist with the positive location of the saw body relative to the mandrel.

The pilot drill bit of the present invention is preferably similar to a conventional drill bit being circular in cross-section with a tip, a cutting portion arranged helically about an outer end of the bit, a shank portion and a butt end. The butt end of the pilot drill bit is typically provided with a flattened portion formed typically by machining a circular segment from the cross-section of the shank of the drill at the butt end. The flattened portion is provided in a preferred form of the invention to attach the drill bit temporarily to the mandrel.

Normally, a grub screw or similar will also be provided to engage the flattened portion to attach the drill bit to the mandrel such that the bit rotates with the mandrel in a fixed orientation. Providing a threaded screw or the like allows removal of the drill bit for replacement of refurbishment. There is also typically at least one shaped portion associated with the shank of the drill bit which is a part of the attaching mechanism to attach the saw body to the mandrel. The function of the shaped portion in general is to provide an engagement portion to facilitate attachment of the saw body to the mandrel.

In a first preferred embodiment, the shaped portion includes at least one and normally a pair of opposed scalloped depressions in the shank. The scalloped depressions preferably provide a portion of reduced thickness or dimension to one part of the shank of the drill bit in a first direction and full thickness in a direction perpendicular to the portion of reduced thickness.

There may be more than one shaped portion spaced over the length of the shank of the drill bit.

In an alternative embodiment, the shaped portion may include an enlarged portion shaped to fit about the shank of the drill bit and be at least temporarily secured there. This embodiment may limit the need for machining the drill bit which may be difficult and also may weaken the drill bit.

The shaped portion of both embodiments is shaped to provide a camming action used in the attachment of the saw body to the mandrel. Again, the shaped portion is adapted to provide a portion of reduced thickness or dimension to one part of the shank of the drill bit in a first direction and greater thickness in a direction offset from, and generally perpendicular to, the portion of reduced thickness.

The mandrel is configured to be coupled to a source of rotational power. As stated above, the rotational power will normally be a power drill. The mandrel will normally have a first end or shaft configured to be coupled to the source of rotational power. The first end will typically include an elongate shaft, of which at least a portion is generally shaped for gripping by a drill chuck. Normally, the shaft will be of a hexagonal cross-sectional shape. There will normally be an opening located in the first end of the mandrel. The opening will typically extend transversely to the longitudinal axis of the shaft and be at least partially threaded and adapted to receive a grub screw used to attach the pilot drill bit to the mandrel.

The mandrel will also typically have a second end supporting an outwardly extending flange. The flange will normally extend radially from the shaft and which is substantially planar. The flange will preferably have a central opening therethrough to receive the shank and butt end of the drill bit, the opening extending through the flange and partially into the shaft of the mandrel, at least to a location adjacent the transverse opening. The opening may be circular as this shape is simple to form but different shapes may be used for example, a partially circular opening with a circular segment removed from the circle to correspond to the cross-section of the shank of the drill at the butt end.

The outwardly extending flange will normally be of approximately the same dimension as the saw body. However, as a result of the action of the invention, a saw body of smaller or larger diameter may be attached to a mandrel of a different dimension. Extending from the edge of the outwardly extending flange is preferably a sidewall which extends in a direction parallel to the longitudinal axis of the elongate mandrel shaft. The sidewall and the outwardly extending flange define an open cavity into which other components of the hole saw and particularly the locking mechanism are housed. The sidewall has an outer (or upper ) free edge.

There is further at least one and normally a pair of opposed slot openings in the sidewall. The slot openings are configured as guide openings for corresponding portions of the locking mechanism allowing longitudinal movement of components seated therein but not rotational movement of the seated component independently of the mandrel.

The side wall will also typically be provided with a pair of opposed openings to receive threaded retention members therethrough which, as will become more clear below, act to retain portions of the locking mechanism in position and allow rotational movement but not longitudinal movement thereof. These openings are normally offset by approximately 90° to the slot openings in the side wall.

The hole saw of the present invention also includes a locking mechanism to releasably lock the saw body relative to the mandrel. The locking mechanism is preferably formed from multiple components that interact to provide the locking and release action. According to a particularly preferred embodiment, the locking mechanism includes at least a saw body attachment portion, a gripping ring, a lock member and a biasing means to bias the lock member into the locked or engaged condition.

The biasing means is preferably a spring or similar which will normally be located concentrically about the shank of the pilot drill bit. The biasing means is preferably located between the outwardly extending flange of the mandrel and the lock member to bias the lock member away from the outwardly extending flange.

The lock member is preferably a plate member with at least one and normally a pair of locking arms extending perpendicularly to the plate. The plate will also typically have a central opening through which the pilot drill bit is received. The plate will preferably be shaped to be received within the cavity defined by the outwardly extending flange and side wall of the mandrel. The locking arms are preferably seated at least partially within the slot openings in the side wall of the mandrel. As a result of this seating, the lock member can move longitudinally against the biasing force of the biasing means towards the mandrel, but cannot rotate independently of the mandrel.

Each of the locking arms will typically have at least one opening therein and preferably each opening is a threaded opening to engage a suitably threaded corresponding member. Each of the lock arms will also preferably be at least partially rectangular in shape.

The gripping ring is typically an annular member adapted to receive the side wall of the mandrel and to be moveable in relation thereto. The ring is preferably provided with grip enhancing means located on an outer surface. There is normally at least one and preferably a pair of openings in the gripping ring to receive threaded fasteners therein to attach the gripping ring to the lock member and allow the lock member (which is located within the cavity of the mandrel) to be moved.

The saw body attachment portion is normally a circular member comprising a main body with a pair of spaced apart, radially extending flanges. A first flange is dimensioned to fit entirely within the cavity defined in the mandrel by the side wall and also between the locking arms of the lock member. The first flange preferably does not restrict the rotation of the lock member relative to the saw body attachment portion. A second flange is preferably spaced along the main body from the first flange and is preferably dimensioned to abut the end edge of the side wall of the mandrel and prevent the saw body attachment portion being received into the cavity in the mandrel. There is also at least one and preferably a pair of openings in the second flange to receive and engage the locking arms of the lock member in the engaged condition.

The pair of flanges are spaced longitudinally along the main body defining an annular channel between the flanges. The channel is adapted to receive at least one and normally two retention means that releasably attach the side wall of mandrel to the saw body attachment portion and allow relative rotational movement but not relative longitudinal movement thereof. The retention members preferably extend through the side wall of the mandrel and partially into the channel to allow the saw body attachment portion to rotate relative to the lock member and mandrel when in the free condition. Engagement of the lock arms within the openings in the second flange preferably locks the saw body attachment portion to the mandrel and lock member such that all three components rotate together.

Drawing the gripping ring towards the shaft of the mandrel typically removes the locking arms from the openings in the second flange allowing rotation of the saw body attachment portion relative to the mandrel and lock member.

Located substantially centrally on the circular surface of the second flange is a seating extension used to seat the saw body properly relative to the saw body attachment portion. The seating extension preferably extends longitudinally and also preferably possesses a longitudinal opening therethrough to receive the pilot drill bit.

The seating extension is typically shaped to engage the aperture in the base end of the saw body and the respective shapes of the seating extension and the aperture will typically correspond closely to one another in order to enhance the seating. There will further preferably be a transverse opening extending through the seating extension and intersect the longitudinal opening. The transverse opening is preferably located such that when the pilot drill bit is properly located or attached to the mandrel and when the saw body attachment portion is properly located relative to the mandrel, the shaped portion of the pilot drill is adjacent the transverse opening. There is normally at least one locking member seated at least partially within the or each transverse opening, hi the engaged condition, the drill bit is rotated relative to the saw body attachment portion to force the locking member located in the transverse opening outwardly engaging the transverse opening in the base end of the saw body, thus attaching the saw body to the saw body attachment portion. In the free condition, the drill bit is rotated relative to the saw body attachment portion to align the portion of smaller dimension with the transverse opening and locking members located therein, allowing the locking members to move to the smaller dimensioned portion, away from the transverse opening in the base end of the saw body, disengaging the saw body from the saw body attachment portion. The locking members of the particularly preferred embodiment are preferably ball bearings or spherical members as this shape is motivated for movement in a particular direction given a force applied from a particular direction. For example, the spherical shape motivated the locking members to move into the transverse openings in the seating extension of the saw body attachment portion when a small force is applied longitudinally to the saw body.

Therefore, according to the particularly preferred embodiment, in the engaged condition, the saw body attachment portion is locked to the mandrel and lock member such that the components rotate together, and the locking members in the seating extension are forced outwardly, locking the saw body to the saw body attachment portion. In the free condition, the saw body attachment portion can rotate relative to the mandrel and the locking members in the seating extension can move away from the smaller dimensioned portion associated with the pilot drill bit, freeing the saw body. To detach or free the saw body, the gripping ring is moved towards the drill chuck, removing the lock arms of the lock member from the openings in the second flange of the saw body attachment portion allowing rotation of the lock member relative to the saw body attachment portion, which rotation in turn allows the locking members in the seating extension to move towards the smaller dimensioned portion associated with the pilot drill bit by removing the obstruction holding the locking members outwardly.

To attach and lock the saw body, the gripping means/lock member is rotated until the lock arms of the lock member are aligned with the openings in the second flange of the saw body attachment portion and the biasing means forces the lock arms into the openings locking the components into rotation together.

With the foregoing in view, the present invention in one form, resides broadly in an adjustable level and square including an elongate body portion having a cutout portion therein and having at least one levelling means associated therewith an elongate arm portion rotatably mounted to the elongate body portion about an axis and having at least one levelling means associated therewith, position fixing means associated with the axis of rotation and adapted to releasably fix the position of the elongate arm portion relative to the elongate body portion in each of a folded condition and at least one unfolded condition, the elongate arm portion shaped and dimensioned to be received and stored within the cutout portion in the elongate body portion in the folded condition and when in a fully unfolded, square condition, a portion of the elongate arm portion abuts a portion of the elongate body portion to prevent further movement of the elongate arm portion past the fully unfolded square condition.

The adjustable level of the invention is of the type commonly referred to as a "carpenter's level". The adjustable level includes at least two parts with the parts being movable relative to one another to define a carpenter's square. Preferably, the parts are movable relative to one another and such that the parts define a carpenter's square when at the limit of their movement.

The adjustable level includes an elongate body portion having a cutout portion therein and having at least one levelling means associated therewith. The elongate body portion is preferably substantially rectangular in shape. According to this embodiment, the body portion has a top wall, a bottom wall, front and rear walls and a pair of opposed ends, designated as the pivot end and the non-pivot end respectively for convenience only.

The body portion may be hollow or solid according to use and manufacture. Preferably, the cutout portion is located towards one end, and normally extends to an end. According to the preferred embodiment, the cutout portion extends to the pivot end of the body portion. Typically, the non-pivot end contains the at least one levelling means.

According to a particularly preferred embodiment, the cutout portion is defined by an inner surface of the rear wall and an inner surface of the top wall, with the top wall and rear wall configured in an L-shape, and the cutout portion is bordered at the non-pivot end by a wall of the body portion.

The pivot end of the body portion is typically provided with a lower wall portion normally attached to or extending from the rear wall. Further, there is preferably a portion removed from the rear wall adjacent the pivot end of the body portion to form a terminal end of the rear wall adjacent the pivot end of the body portion. This terminal end is typically a planar end which as will be seen below, it is important to the functioning of the invention.

The lower wall and the corresponding portion of the top wall of the body portion are preferably located opposite one another and correspond to one another to define the pivot end of the body portion. The lower wall and the corresponding portion of the top wall are also preferably configured for use as attachment arms to attach the elongate arm portion to the body portion. There is preferably an opening in each of the lower wall and the corresponding portion of the top wall and normally, these openings are aligned or coaxial. These openings preferably receive components of the position fixing means.

The body portion may further be provided with marking indicia to allow the body portion to be used as a measuring instrument. Normally, these marking indicia are provided on an outer surface of the top wall. However indicia maybe provided on any of the walls.

The body portion also preferably includes one or more openings therein in order to allow the levelling means provided to be viewed from a variety of angles. This increases the functionality of the adjustable level.

Adjacent either end of the body portion is preferably at least one deployable foot portion. Each deployable foot portion is typically located relative to an outer surface of the bottom wall of the body portion. The foot portions are movable between a stored position and a deployed position. When in the stored position each of the foot portions is typically flush with the bottom wall of the body portion allowing the adjustable level to be placed on the bottom wall for use as a level without any deviation or irregularity caused by the foot portions.

When the foot portions are deployed, they are preferably approximately perpendicular to the plane of the bottom wall. When deployed, the foot portions are typically used to abut an edge of a work piece in order to allow the adjustable level to be used as a carpenter's square.

Each of the foot portions is preferably a C-shaped section with side arms of the c-shaped section received in rebates extending along a lower part of the front and rear wall at either end of the body portion extending along a lower part of the front and rear wall at either end of the body portion. Each arm preferably has at least one opening through which a connection pin is received in order to attach the foot portions to the elongate body portion and to allow the foot portions to pivot about said pin.

The adjustable level also includes an elongate arm portion rotatably mounted to the elongate body portion about an axis and having at least one levelling means associated therewith.

The arm portion is typically shaped and attached to the body portion to be received within the cutout portion of the body portion. When the arm portion is in the folded condition, the arm portion and body portion preferably form a rectangular prism shape.

The arm portion is shaped to correspond closely with the shape of the cutout portion in the main body portion. The arm portion will preferably include a pair of spaced apart arms located at a first end. These spaced apart arms will typically function as attachment arms in order to attach the arm portion to the body portion. When the adjustable level is assembled, the attachment arms of the arm portion preferably received between the attachment arms of the main body portion.

Preferably, a substantially C-shaped opening is provided at one end of the arm portion to form the attachment arms. A component of the position fixing means, namely a grip knob, will typically be received between the attachment arms of the arm portion. The C-shaped opening will preferably also allow the insertion of a user's fingers in order to a grip and turn the grip knob.

Each of the attachment arms will also typically include an opening adapted to receive components of the position fixing means, and which also define the axis about which the main body portion and arm portion rotate relative to one another.

Generally, a lower side of the lower attachment arms is provided with a rebate to receive the lower wall of the main portion when in the folded condition.

The arm portion may further be provided with marking indicia to allow the arm portion to be used as a measuring instrument. Normally, these marking indicia are provided on an outer surface of the top wall. However indicia may be provided on any of the walls.

There may also preferably be secondary markings provided on the arm portion, typically adjacent the pivot end of the arm portion to allow the measurement of the angle formed between the main body portion and the ami portion.

According to the invention, each of the main body portion and arm portion are provided with at least one levelling means. The levelling means maybe of any type, for example liquid vials or digital levelling means or similar. The levelling means may be oriented in any direction. For example, it is normal practice with levels to have at least one levelling means oriented in the first direction with a second levelling means oriented in a second direction substantially perpendicular to the first direction. Other levelling means may be provided at different angles, for example approximately 45°. There will normally be openings provided in or through each of the body portion and arm portion in order to seat the levelling means. There may further be secondary openings provided in order to allow the levelling means to be viewed from different directions when the adjustable level is in the folded and the unfolded conditions.

The adjustable level also includes position fixing means associated with the axis of rotation and adapted to releasably fix the position of the elongate arm portion relative to the elongate body portion in each of a folded condition and at least one unfolded condition. The position fixing means will typically include at least one pivot pin and a grip knob. Normally, there will be a pair of pivot pins. Each of the pivot pins will preferably be a threaded pin having an enlarged head portion. The enlarged head portions of the respective pivot pins will preferably be received in depressions in an outer surface of each of the top wall and bottom wall. The pivot pins will typically be provided one extending from above and one from below the aligned attachment openings provided in each of the arm and body portions. Typically, the grip knob will be provided between the attachment arms of the arm portion and the insertion of the pivot pins will fix the position of the grip knob. The pivot pins will preferably allow the rotation of the arm and body portions relative to one another. The respective pivot pins are threaded such that the grip knob can be used to tighten or loosen the attachment between the body portion and the arm portion in order to releasably fix the position of the body portion and arm portion relative to one another. According to normal operation, rotation of the grip knob will draw the attachment arms of the body portion together which in turn preferably clamps the attachment arms of the arm portion between the arms of the body portion and the grip knob. Rotation of the grip knob in the opposite direction will preferably release the clamping action. The pivot pins may be threaded such that there is a central release position and rotation of the grip knob in either direction acts to engage the clamping action.

Associated components such as washers or other seating means may be provided. Preferably, at least one grub screw is associated with each of the pivot pins, and preferably the enlarged head portion of each pivot pin in order to fix the position of the pivot pin relative to the body portion and prevent rotation thereof.

The grip knob is typically substantially cylindrical with a central bore the through, and the bore is typically threaded in order to engage the threaded pins. The grip knob preferably has a knurled or similar outer surface.

According to a particularly preferred embodiment of the present invention the fully unfolded condition of the adjustable level has the arm rotated through 270° and the arm portion abuts the terminal end of the rear wall of the body.

The terminal end of the rear wall of the body limits movement of the arm any further and forms a 90° square between the arm portion and the body portion.

There are a plurality of partially unfolded conditions which also may be used. As the relative positions of the arm portion and the body portion can be fixed, this allows the adjustable level of the invention to be used as a protractor of sorts.

The adjustable level of the invention may be of any dimension. Preferably however, the adjustable level will be sized to allow a user to carry the level on a person.

As to material of construction, it is preferred that a light metal such as aluminium is used for construction of a high end, premium tool. A plastic tool may be manufactured for beginners or as a less expensive alternative to the premium tool, however a metal level is preferred for accuracy as it is likely to undergo lesson deformation and is also less prone to be damaged.

Brief Description of the Drawings.

Various embodiments of the invention will be described with reference to the following drawings, in which: Figure 1 is an exploded view of a hole saw according to a particularly preferred embodiment of the present invention.

Figure 2 is a perspective view of the hole saw illustrated in Figure 1 in the fully assembled, use condition.

Figure 3 is a partially sectional perspective view of the hole saw illustrated in Figure 2 showing the internal engagement.

Figure 4 is a partially sectional perspective view of the hole saw illustrated in Figure 2 with the locking mechanism partially disengaged.

Figure 5 is a partially sectional perspective view of the hole saw illustrated in Figure 2 with the locking mechanism folly disengaged and the saw body free of the mandrel.

Figure 6 is a perspective view of a mandrel assembly as illustrated in Figure 1. Figure 7 is a partially sectional perspective view of the internal components of a mandrel with the locking mechanism disengaged.

Figure 8 is a sectional side view of the hole saw illustrated in Figure 1 with the locking mechanism folly engaged.

Figure 9 is a perspective view of a level according to a preferred embodiment of the present invention, in the folded condition (the level embodiment).

Figure 10 is a perspective view of a level according to a preferred embodiment of the present invention in a partially unfolded condition.

Figure 11 is a perspective view of a level according to a preferred embodiment of the present invention in a 90° unfolded configuration. Figure 12 is a perspective view of a level according to a preferred embodiment of the present invention in a 270° unfolded configuration.

Figure 13 is a perspective exploded view of a level according to a preferred embodiment of the present invention.

Detailed Description of the Preferred Embodiment. According to the particularly preferred embodiment illustrated, a hole saw 10 is provided.

The hole saw 10 illustrated in Figure 1 in particular includes a. a saw body 11 having i. a base end 12 with a longitudinal aperture 13 therethrough and a transverse opening 14 intersecting the longitudinal aperture 13, ii. a side wall 15 extending from the base end 12 and defining an interior cavity 16 and an outer edge 17 with a plurality of cutting teeth 18 formed on the outer edge 17; and b. a mandrel 19 having i. a shaft 20 on a first end configured to be coupled to a source of rotational power (not illustrated) ii. an outwardly extending flange 21 extending from the shaft 20; iii. a side wall 22 extending from the outwardly extending flange 21 having an outer edge 23 and defining an interior cavity 24; c. a pilot drill bit 25 adapted for rotation with the shaft 20 of the mandrel 19 and having a shank 26 and a cutting portion 27 with a pair of scalloped portions 28 located on the shank 26; and d. a locking mechanism 29 to releasably lock the saw body 11 relative to the mandrel 19, the locking mechanism 29 including i. a saw body attachment portion 30 with a longitudinal opening 31 therethrough to receive the pilot drill bit 25, a transverse opening 32 intersecting the longitudinal opening 31, a locking member 33 seated at least partially in the transverse opening 32 and movable between an engaged condition in which the locking member 33 is forced outwardly to engage the transverse opening 14 in the saw body 11 to releasably lock the saw body 11 to the mandrel 19, and a free condition in which the locking member 33 is disengaged from the transverse opening 14 in the saw body

11 allowing removal of the saw body 11 from the mandrel 19; ii. a lock member 34 having a longitudinal opening 35 therethrough to receive the pilot drill bit 25, and a pair of locking arms 36 to releasably lock rotation of the lock member 34 relative to the saw body attachment portion 30 and movable between an engaged condition in which the rotation is locked and a free condition where the lock member 34 can be rotated independently of the saw body attachment portion 30; wherein movement of the lock member 34 to the engaged condition also moves the locking member 33 to the engaged condition to releasably lock the saw body 11 to the mandrel 19 and movement of the lock member 34 to the free condition also moves the locking member 33 to the free condition to disengage the saw body 11 from the mandrel 19.

The present invention is adapted to allow a quick and easy but still secure mechanism for the attachment of a saw body 11 to a mandrel 19. All of the main components of the hole saw 10 are substantially circular in cross-section in order to rotate efficiently and minimise vibration and the like. Where possible, the position of the components of the hole saw of the invention will normally be described relative to each other along the main longitudinal axis. The saw body 11 provided in the hole saw 10 of the illustrated embodiment is generally cylindrical with an open end located opposite the base end 12. The base end 12 of the saw body 11 is of greater thickness than the sidewall 15 of the saw body 11. The aperture 13 in the base end 12 is centrally located in order to mount the saw body 11 for rotation. The aperture 13 of the illustrated embodiment is a shaped opening, in order to positively locate and engage the saw body 12 relative to the mandrel 19. The aperture is shaped having a pair of parallel sides linked by a pair of arcuate ends. This prevents a circular member being inserted and the parallel sides provide a positive contact surface as illustrated in Figures 3 to 5 in particular.

There is also a transverse opening 14 provided in the base end 12 of the saw body 11 which is regarded as a single opening extending through the base end, even though the opening is divided when it intersects the aperture 13. The transverse opening 14 extends through the base end 12 perpendicularly to the longitudinal aperture 13 and axis of rotation, intersecting the longitudinal aperture 13.

The transverse opening 14 is to receive a correspondingly shaped portion of the locking mechanism 29 therein to releasably lock the saw body 11 relative to the mandrel 19. The transverse opening 14 is normally circular in cross- sectional shape. As illustrated in Figure 1, there are a pair of cut-out portions 37 through the side wall 15 of the saw body 11 to facilitate removal of the plug formed when the saw is used, namely that removed from the material through which the saw cuts.

The base end 12 of the saw body 11 is a planar surface. The pilot drill bit 25 of the illustrated embodiment is similar to a conventional drill bit being circular in cross-section with a tip 38, a cutting portion 27 arranged helically about an outer end of the bit, a shank portion 26 and a butt end. The butt end of the shank 26 is provided with a flattened portion 39 formed by machining a circular segment from the cross-section of the shank 26 of the drill bit at the butt end. The flattened portion 39 is provided to attach the drill bit 25 temporarily to the mandrel 19 as best illustrated in Figure 7.

According to the illustrated embodiment, a grab screw 40 is provided through an opening 41 in the shaft 20 of the mandrel 19 to engage the flattened portion 39 to attach the drill bit 25 to the mandrel 19 such that the bit 25 rotates with the mandrel 19 in a fixed orientation. Providing a threaded grub screw 40 allows removal of the drill bit 25 for replacement of refurbishment.

The scalloped depressions 28 in the shank 26 of the drill bit 25 of the illustrated embodiment provide a portion of reduced thickness or dimension to one part of the shank 26 of the drill bit 25 in a first direction and full thickness in a direction perpendicular to the scalloped depressions 28.

The depressions 28 are shaped to provide a camming action used in the attachment of the saw body 11 to the mandrel 19. The mandrel 19 is configured to be coupled to a source of rotational power. As stated above, the rotational power will normally be a power drill. The shaft 20 of the mandrel 19 is shaped for gripping by a drill chuck (not shown).

The opening 41 located in the shaft 20 of the mandrel 19 extends transversely to the longitudinal axis of the shaft 20 and is threaded to receive the grub screw 40 used to attach the pilot drill bit 25 to the mandrel 19.

The mandrel 19 also has an outwardly extending flange 21 extending radially from the shaft 20 and being substantially planar. The flange has a central opening 42 therethrough to receive the shank 26 and butt end of the drill bit 25, the opening 42 extending through the flange 21 and partially into the shaft 20 of the mandrel 19, at least to a location adjacent the opening 41 for attachment of the drill bit 25.

The central opening 42 of the illustrated embodiment is circular as this shape is simple to form. The outwardly extending flange 21 of the illustrated embodiment is of approximately the same dimension as the saw body 11. Extending from the edge of the outwardly extending flange 21 is a sidewall 22 which extends in a direction parallel to the longitudinal axis of the elongate mandrel shaft 20. The sidewall 22 and the outwardly extending flange 21 define an open cavity 24 into which other components of the hole saw 10 and particularly the locking mechanism 29 are housed. The sidewall 22 has an outer (or upper) edge 23.

There is a pair of opposed slot openings 43 in the sidewall 22. The slot openings 43 are configured as guide openings for the locking arms 36 of the lock member 34 allowing longitudinal movement of locking arms 36 seated therein but not rotational movement of the locking arms 36 (and therefore of the lock member 34) independently of the mandrel 19.

The side wall 22 of the illustrated embodiment also has a pair of opposed openings 44 to receive threaded retention screws 45 therethrough which, as will become more clear below, act to retain the lock member 34 in position and allow rotational movement but not longitudinal movement thereof. These openings 44 are offset by approximately 90° to the slot openings 43 in the side wall 22.

The hole saw 10 includes a locking mechanism 29 formed from multiple components that interact to provide the locking and release action, to releasably lock the saw body 11 relative to the mandrel 19.

According to the illustrated embodiment, the locking mechanism 29 includes a saw body attachment portion 30, a gripping ring 46, a lock member 34 and a spring 47 to bias the lock member 34 into the engaged condition.

The spring 47 is located concentrically about the shank 26 of the pilot drill bit 25, between the outwardly extending flange 21 of the mandrel 19 and the lock member 34 to bias the lock member 34 away from the outwardly extending flange 21.

The lock member 34 of the illustrated embodiment is a plate member with a pair of locking arms 36 extending perpendicularly to the plate. The lock member 34 also has a central opening 35 through which the pilot drill bit 25 is received. The lock member 34 is shaped to be received within the cavity 24 defined by the outwardly extending flange 21 and side wall 22 of the mandrel 19. The locking arms 36 are seated at least partially within the slot openings 43 in the side wall 22 of the mandrel 19. As a result of this seating, the lock member 34 can be moved longitudinally against the biasing force of the spring 47 towards the mandrel 19, but cannot rotate independently of the mandrel 19.

Each of the locking arms 36 has a threaded opening 48 therein to engage a suitably threaded corresponding fastener 49 to attach the gripping ring 46 to the lock member 34. Each of the lock arms 36 of the illustrated embodiment is rectangular in shape. The gripping ring 46 is an annular member adapted to receive the side wall 22 of the mandrel 19 and to be moveable longitudinally in relation thereto. The ring 46 is provided with grip enhancing means located on an outer surface. There is a pair of openings 50 in the gripping ring 46 to receive threaded fasteners 49 therein to attach the gripping ring 46 to the lock member 34 and allow the lock member 34 (which is located within the cavity 24 of the mandrel 19) to be moved.

The saw body attachment portion 30 of the illustrated embodiment is a circular member comprising a main body with a pair of spaced apart, radially extending flanges. A first flange 51 is dimensioned to fit entirely within the cavity 24 defined in the mandrel 19 by the side wall 22 and also between the locking arms 36 of the lock member 34. The first flange 51 does not restrict the rotation of the lock member 34 relative to the saw body attachment portion 30.

A second flange 52 is spaced along the main body from the first flange 51 and is dimensioned to abut the end edge 23 of the side wall 22 of the mandrel 19 and prevent the saw body attachment portion 30 being received into the cavity 24 in the mandrel 19. There is also a pair of slot openings 53 in the second flange 52 to receive and engage the locking arms 36 of the lock member 34 in the engaged condition. The pair of flanges 51, 52 are spaced longitudinally along the main body defining an annular channel 54 between the flanges. The channel 54 is adapted to receive retention screws 45 that releasably attach the side wall 22 of mandrel 19 to the saw body attachment portion 30 and allow relative rotational movement but not relative longitudinal movement thereof. The retention screws 45 extend through the side wall 22 of the mandrel 19 and partially into the channel 54 to allow the saw body attachment portion 30 to rotate relative to the lock member 34 and mandrel 19 when in the free condition. Engagement of the lock arms 36 within the slot openings 53 in the second flange 52 locks the saw body attachment portion 30 to the mandrel 19 and lock member 34, such that all three components rotate together. Drawing the gripping ring 46 towards the shaft 20 of the mandrel 19 removes the locking arms 36 from the slot openings 53 in the second flange 52 allowing rotation of the saw body attachment portion 30 relative to the mandrel 19 and lock member 34.

Located substantially centrally on the circular surface of the second flange 52 is a seating extension 55 used to seat the saw body 11 properly relative to the saw body attachment portion 30. The seating extension 55 extends longitudinally and also possesses a longitudinal opening 31 therethrough to receive the pilot drill bit 25. The seating extension 55 is shaped to engage the aperture 13 in the base end 12 of the saw body 11 and the respective shapes of the seating extension 55 and the aperture 13 correspond closely to one another in order to enhance the seating.

The transverse opening 32 extends through the seating extension 55 and intersects the longitudinal opening 31. The transverse opening 32 is located such that when the pilot drill bit 25 is properly located or attached to the mandrel 19 and when the saw body attachment portion 30 is properly located relative to the mandrel 19, the scalloped depressions 28 of the pilot drill 25 are adjacent the transverse opening 32. There is a locking member 33 seated at least partially within the transverse opening 32. hi the engaged condition, the drill bit 25 is rotated relative to the saw body attachment portion 30 to force the locking member 33 located in the transverse opening 32 outwardly, engaging the transverse opening 14 in the base end 12 of the saw body 11, thus attaching the saw body 11 to the saw body attachment portion 30.

In the free condition, the drill bit 25 is rotated relative to the saw body attachment portion 30 to align the scalloped depressions 28 with the transverse opening 32 and locking members 33 located therein, allowing the locking members 33 to move into the scalloped depressions 28, away from the transverse opening 14 in the base end 12 of the saw body 11, disengaging the saw body 11 from the saw body attachment portion 30.

The locking members 33 of the illustrated embodiment are spherical ball bearings as this shape is motivated for movement in a particular direction given a force applied from a particular direction. For example, the spherical shape motivates the locking members 33 to move into the transverse openings 32 in the seating extension 55 of the saw body attachment portion 30 when a small force is applied longitudinally to the saw body 11.

Therefore, according to the illustrated embodiment, in the engaged condition as illustrated in Figures 3 and 8, the saw body attachment portion 30 is locked to the mandrel 19 and lock member 34 such that the components rotate together, and the locking members 33 in the seating extension 55 are forced outwardly, locking the saw body 11 to the saw body attachment portion 30. In the free condition as illustrated in Figure 5, the saw body attachment portion 30 can rotate relative to the mandrel 19 and the locking members 33 in the seating extension 55 can move away from the scalloped depressions 28 of the pilot drill bit 25, freeing the saw body 11. To detach or free the saw body 11, the gripping ring 46 is moved towards the drill chuck, removing the lock arms 36 of the lock member 34 from the slot openings 53 in the second flange 52 of the saw body attachment portion 30 allowing rotation of the lock member 34 relative to the saw body attachment portion 30, which rotation in turn allows the locking members 33 in the seating extension 55 to move towards the scalloped depressions 28 associated with the pilot drill bit 25 by removing the obstruction holding the locking members 33 outwardly. This sequence is illustrated in Figures 4 and 7.

To attach and lock the saw body 11, the gripping means 46/lock member 34 is rotated until the lock arms 36 of the lock member 34 are aligned with the slot openings 53 in the second flange 52 of the saw body attachment portion 30 and the spring 47 forces the lock arms 36 into the slot openings 53, locking the components into rotation together.

In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

The operation and use of the adjustable level 60 of a particularly preferred embodiment is best illustrated in Figures 9 to 12, and the components of that embodiment are best illustrated in Figure 13,

The adjustable level and square 60 illustrated in the accompanying figures includes an elongate body portion 61 having a cutout portion 61 therein and at a levelling means 63 associated therewith. The level 60 also includes an elongate arm portion 64 rotatably mounted to the elongate body portion 61 about an axis and has a pair of levelling means 63 associated therewith A position fixing mechanism 65 is associated with the axis of rotation and is adapted to releasably fix the position of the elongate arm portion 64 relative to the elongate body portion 61 in each of a folded condition and at least one unfolded condition, the elongate arm portion 64 shaped and dimensioned to be received and stored within the cutout portion 62 in the elongate body portion 61 in the folded condition and when in a fully unfolded, square condition, a portion of the elongate arm portion 64 abuts a portion of the elongate body portion 61 to prevent further movement of the elongate arm portion 64 past the fully unfolded square condition.

The elongate body portion 61 of the illustrated embodiment is substantially rectangular in shape. According to this embodiment, the body portion has a top wall 66, a bottom wall 67, front 68 and rear 69 walls and a pair of opposed ends, designated as the pivot end and the non-pivot end respectively for convenience only.

The cutout portion 62 is located towards the pivot end of the body portion 61, and extends to the end. The non-pivot end contains the levelling means 63.

According to the illustrated embodiment, the cutout portion 62 is defined by an inner surface 70 of the rear wall 69 and an inner surface (not shown) of the top wall 66, with the top wall 66 and rear wall 69 configured in an L-shape. The cutout portion 62 is bordered at the non-pivot end by an end wall 71 of the body portion 61.

The pivot end of the body portion 61 is provided with a lower wall portion 72 extending from the rear wall 69. Further, there is preferably a portion removed from the rear wall 69 adjacent the pivot end of the body portion 61 to form a terminal end 73 of the rear wall 69 adjacent the pivot end of the body portion 61. The terminal end 73 of the illustrated embodiment is a pair of planar ends.

The lower wall 72 and the corresponding portion of the top wall 66 of the body portion 61 are located opposite one another and correspond to one another to define the pivot end of the body portion 61. The lower wall 72 and the corresponding portion of the top wall 66 are configured for use as attachment arms to attach the elongate arm portion 64 to the body portion 61. There is an opening 74 in each of the lower walls 72 and the corresponding portion of the top wall 66 and these openings 74 are aligned. These openings 74 receive components of the position fixing means 65.

The body portion 61 of the illustrated embodiment is provided with marking indicia on an outer surface of the top wall 66 to allow the body portion 61 to be used as a measuring instrument.

The body portion 61 includes an opening 75 therein in order to allow the levelling means 63 to be attached to the body portion 61 and a secondary opening

76 provided to allow the levelling means 63 to be viewed from above the level 60. Adjacent either end of the body portion 61 is a deployable foot portion

77. Each deployable foot portion 77 is located relative to an outer surface of the bottom wall 67 of the body portion 61 and are movable between a stored position

(illustrated in Figure 9) and a deployed position (illustrated in Figure 10). When in the stored position, each of the foot portions 77 is flush with the bottom wall 67 of the body portion 61 allowing the adjustable level 60 to be placed on the bottom wall 67 for use as a level without any deviation or irregularity caused by the foot portions 77.

When the foot portions 77 are deployed, they are approximately perpendicular to the plane of the bottom wall, as illustrated in Figure 10. When deployed, the foot portions 77 can be used to abut an edge of a work piece in order to allow the adjustable level to be used as a carpenter's square.

Each of the foot portions 77 of the illustrated embodiment is a C- shaped section with side arms 78 and of the c-shaped section received in rebates 79 extending along a lower part of the front 68 and rear 69 wall at either end of the body portion 61 and the body 80 of the c-shaped sections received in a rebate 79 extending along and across the bottom wall 67 at either end of the body portion 61. Each side arm 78 has an opening 81 through which a connection pin 82 is received in order to attach the foot portions 77 to the elongate body portion 61 and to allow the foot portions 77 to pivot about said pin 82.

The elongate arm portion 64 is shaped and attached to the body portion 61 to be received within the cutout portion 62 of the body portion 61. When the arm portion 64 is in the folded condition, the arm portion 64 and body portion 61 form a rectangular prism shape as illustrated in Figure 9. The arm portion 64 is shaped to correspond closely with the shape of the cutout portion 62 in the main body portion 61. The arm portion 64 includes a pair of spaced apart arms 83 located at a first end which function as attachment arms in order to attach the arm portion 64 to the body portion 61. When the adjustable level is assembled, the arms 83 of the arm portion 64 are received between the top wall 66 and lower wall portion 72 at the pivot end of the main body portion 61.

According to the illustrated embodiment, a substantially C-shaped opening 84 is provided at one end of the arm portion 64 to form the attachment arms

83. A grip knob 85 is received between the attachment arms 83 of the arm portion 64. The C-shaped opening 84 also allows the insertion of a user's fingers in order to a grip and turn the grip knob 85.

Each of the attachment arms 83 include an opening 86 adapted to receive components of the position fixing means 65, and which also define the axis about which the main body portion 61 and arm portion 64 rotate relative to one another.

Generally, a lower side of the lower attachment arm is provided with a rebate 87 to receive the lower wall 72 of the main portion 61 when in the folded condition.

The arm portion 64 is also provided with marking indicia to allow the arm portion 64 to be used as a measuring instrument. The illustrated embodiment has the marking indicia provided on an outer surface of the top wall.

There are also secondary markings 88 provided adjacent the pivot end of the arm portion 64 to allow the measurement of the angle formed between the main body portion 61 and the arm portion 64. Each of the main body portion 61 and arm portion 64 are provided with levelling means 63 which according to the illustrated embodiment are liquid vials. The arm portion 64 has one levelling means 63 A oriented in a first direction and a second levelling means 63B oriented in a second direction substantially perpendicular to the first direction. Openings 75 are provided in each of the body portion 61 and arm portion 64 in order to seat the levelling means 63. Secondary openings 76 are provided in order to allow the levelling means 63 to be viewed from different directions when the adjustable level 60 is in the folded and the unfolded conditions. The illustrated position fixing means 65 includes a pair of threaded pivot pins 89 each having an enlarged head portion 90, and a grip knob 85. The enlarged head portions 90 of the respective pivot pins 90 are received in depressions in an outer surface of each of the top wall 66 and bottom wall 67 of the body portion 61.

The pivot pins 89 are provided one extending from above and one from below, the aligned attachment openings 74, 86 provided in each of the arm 64 and body 61 portions. Typically, the grip knob 85 is positoned between the attachment arms 83 of the arm portion 64 and the insertion of the pivot pins 89 fixes the position of the grip knob 85.

The pivot pins 89 allow the rotation of the arm 64 and body 61 portions relative to one another. The respective pivot pins 89 are threaded such that the grip knob 85 can be used to tighten or loosen the attachment between the body portion 61 and the arm portion 64 in order to releasably fix the position of the body portion 61 and arm portion 64 relative to one another.

According to normal operation, rotation of the grip knob 85 draws the lower arm portion 72 and the top wall 66 of the body portion 61 together which in turn preferably clamps the attachment arms 83 of the arm portion 64 relative to the body portion 61 and the grip knob 85. Rotation of the grip knob 85 in the opposite direction releases the clamping action.

Washers 91 are provided in the illustrated embodiment. A grub screw 92 is associated with the enlarged head portion 90 of each pivot pin 8 in order to fix the position of the pivot pin 89 relative to the body portion 61 and prevent rotation thereof. The grip knob 85 is substantially cylindrical with a central bore therethrough, and the bore is threaded in order to engage the threaded pins. The grip knob has a knurled outer surface.

According to the operation of the illustrated embodiment of the present invention, the fully unfolded condition of the adjustable level has the arm 64 rotated through 270° and the arm portion 64 abuts the terminal end 73 of the rear wall 69 of the body portion 61 The terminal end 73 of the rear wall 69 of the body 61 limits movement of the arm 64 any further and forms a 90° square between the arm portion 64 and the body portion 61 as illustrated in Figure 4. There is a plurality of partially unfolded conditions which also can be used as illustrated in Figures 10 and 11 for example, As the relative positions of the arm portion 64 and the body portion 61 can be fixed, this allows the adjustable level of the invention to be used as a protractor of sorts. In the present specification and claims (if any), the word "comprising" and its derivatives including "comprises" and "comprise" include each of the stated integers but does not exclude the inclusion of one or more further integers.

Claims

1. A hole saw having a saw body having a base end with a longitudinal aperture therethrough, a side wall extending from said base end and defining an interior cavity and an outer edge, and a plurality of cutting teeth formed on said outer edge; and a mandrel configured to be coupled to a source of rotational power; a saw body attachment portion mounted for rotation relative to the mandrel and a locking mechanism adapted to releasably lock the rotation of the saw body attachment portion to the mandrel, the locking mechanism having an engaged condition and a free condition wherein movement of the locking mechanism to the engaged condition releasably locks the rotation of the saw body attachment portion to the mandrel and movement of the locking mechanism to the free condition disengages the rotation of the saw body attachment portion from the mandrel, allowing independent rotation of the saw body attachment portion and the mandrel.

2. A hole saw as claimed in claim 1 wherein the longitudinal aperture is shaped having a pair of parallel sides linked by a pair of arcuate ends.

3. A hole saw as claimed in either claim 1 or claim 2 further including at least one transverse opening provided in the base end of the saw body extending through the base end perpendicularly to the longitudinal aperture and axis of rotation and intersecting the longitudinal aperture.

4. A hole saw as claimed in any one of the preceding claims wherein a butt end of the pilot drill bit is provided with a flattened portion and a grub screw is provided to engage the flattened portion to attach the drill bit to the mandrel such that the bit rotates with the mandrel in a fixed orientation.

5. A hole saw as claimed in any one of the preceding claims wherein at least one shaped portion is provided on the pilot drill bit to provide an engagement portion to facilitate attachment of the saw body to the mandrel.

6. A hole saw as claimed in claim 5 wherein the at least one shaped portion includes a pair of opposed scalloped depressions in the shank providing a portion of reduced thickness or dimension to one part of the shank of the drill bit in a first direction and full thickness in a direction perpendicular to the portion of reduced thickness.

7. A hole saw as claimed in any one of the preceding claims wherein the mandrel includes a first end configured to be coupled to a source of rotational power, a second end supporting an outwardly extending flange, a side wall extending from said outwardly extending flange having an outer edge and defining an interior cavity, wherein the locking mechanism to releasably lock the saw body relative to the mandrel is located within the interior cavity.

8. A hole saw as claimed in claim 7 wherein the locking mechanism includes a) a saw body attachment portion with a longitudinal opening therethrough to receive the pilot drill bit, at least one transverse opening intersecting the longitudinal opening, a locking member seated at least partially in the transverse opening and movable between an engaged condition in which the locking member is forced outwardly to engage the at least one transverse opening in the saw body to releasably lock the saw body to the mandrel and a free condition in which the locking member is disengaged from the at least one transverse opening in the saw body allowing removal of the saw body from the mandrel; b) a lock member having a longitudinal opening therethrough to receive the pilot drill bit, and at least one locking portion to releasably lock rotation of the lock member relative to the saw body attachment portion and movable between an engaged condition in which the rotation is locked and a free condition where the lock member can be rotated independently of the saw body attachment portion; wherein movement of the at least one locking portion to the engaged condition also moves the locking member to the engaged condition to releasably lock the saw body to the mandrel and movement of the at least one locking portion to the free condition also moves the locking member to the free condition to disengage the saw body from the mandrel.

9. A holes saw as claimed in any one of the preceding claims wherein locking members provided are spherical members as this shape is motivated for movement in a particular direction given a force applied from a particular direction.

10. A hole saw including a. a saw body having i. a base end with a longitudinal aperture therethrough and at least one transverse opening intersecting the longitudinal aperture, ii. a side wall extending from said base end and defining an interior cavity and an outer edge, and iii. a plurality of cutting teeth formed on said outer edge; and b. a mandrel having i. a first end configured to be coupled to a source of rotational power ii. a second end supporting an outwardly extending flange; iii. a side wall extending from said outwardly extending flange having an outer edge and defining an interior cavity; iv. a pilot drill bit adapted for rotation with the first end of the mandrel and having a shank and a cutting portion with at least one shaped portion of reduced dimension located on the shank; and v. a locking mechanism to releasably lock the saw body relative to the mandrel, the locking mechanism including c) a saw body attachment portion with a longitudinal opening therethrough to receive the pilot drill bit, at least one transverse opening intersecting the longitudinal opening, a locking member seated at least partially in the transverse opening and movable between an engaged condition in which the locking member is forced outwardly to engage the at least one transverse opening in the saw body to releasably lock the saw body to the mandrel and a free condition in which the locking member is disengaged from the at least one transverse opening in the saw body allowing removal of the saw body from the mandrel; d) a lock member having a longitudinal opening therethrough to receive the pilot drill bit, and at least one locking portion to releasably lock rotation of the lock member relative to the saw body attachment portion and movable between an engaged condition in which the rotation is locked and a free condition where the lock member can be rotated independently of the saw body attachment portion; wherein movement of the at least one locking portion to the engaged condition also moves the locking member to the engaged condition to releasably lock the saw body to the mandrel and movement of the at least one locking portion to the free condition also moves the locking member to the free condition to disengage the saw body from the mandrel.

11. An adjustable level and square including an elongate body portion having a cutout portion therein and having at least one levelling means associated therewith, an elongate arm portion rotatably mounted to the elongate body portion about an axis and having at least one levelling means associated therewith, position fixing means associated with the axis of rotation and adapted to releasably fix the position of the elongate arm portion relative to the elongate body portion in each of a folded condition and at least one unfolded condition, the elongate arm portion shaped and dimensioned to be received and stored within the cutout portion in the elongate body portion in the folded condition and when in a fully unfolded, square condition, a portion of the elongate arm portion abuts a portion of the elongate body portion to prevent further movement of the elongate arm portion past the fully unfolded square condition.

12. An adjustable level as claimed in claim 11 wherein the elongate arm portion and the elongate body portion are movable relative to one another such that the portions define a carpenter's square when at the limit of their movement in the unfolded condition.

13. An adjustable level as claimed in claim 11 or claim 12 wherein the cutout portion is located towards and extends to one end of the elongate body portion.

14. An adjustable level as claimed in any one of claims 11 to 13 wherein the elongate body portion has a top wall, a bottom wall, front and rear walls, a pivot end and a non-pivot end and the cutout portion is defined by an inner surface of the rear wall and an inner surface of the top wall, with the top wall and rear wall configured in an L-shape, and the cutout portion is bordered at the non-pivot end by a wall of the body portion.

15. An adjustable level as claimed in any one of claims 11 to 14 wherein a pair of opposed attachment flanges are provided adjacent a pivot end of the elongate body portion to receive an end of the eliongate arm portion therebetween.

16. An adjustable level as claimed in any one of claims 11 to 15 wherein the arm portion is shaped to correspond closely with the shape of the cutout portion in the main body portion.

17. An adjustable level as claimed in any one of claims 11 to 16 further including secondary markings provided on the elongate arm portion to allow measurement of the angle formed between the main body portion and the arm portion.

18. An adjustable level as claimed in any one of claims 11 to 17 wherein the elongate main body portion has a pair of attachment flanges between which a pair of spaced apart attachment flanges of the elongate arm portion are received and a grip knob is located between the attachment flanges of the elongate arm portion, and at least one threaded pivot member engaging with an internally threaded poriton of the grip knob.

19. An adjustable level as claimed in claim 18 wherein rotation of the grip knob draws the attachment flanges of the body portion together which in turn clamps the attachment flanges of the arm portion between the arms of the body portion and the grip knob.

20. An adjustable level as claimed in any one of claims 11 to 19 further including at least one deployable foot portion adjacent either end of the body portion, which when deployed, extend approximately perpendicular to a surface of the elongate body portion.