1.  Field of the Invention
The present invention relates generally to power saws, and more specifically, to a forward-cutting power saw having a drive gear assembly that turns a geared blade attachment plate and an adjacent cutting blade of a greater diameter. 
2.  Description of the Prior Art
There are other portable devices designed for cutting.  Typical of these is U.S. Pat.  No.  1,816,966 issued to Albert S. Gray on Aug. 4, 1931. 
Another patent was issued to John W. O""Banion on Jan. 9, 1934 as U.S. Pat.  No.  1,942,766.  Yet another U.S. Pat.  No.  2,139,272 was issued to Charles N. Jaworski on Dec. 6, 1938 and still yet another was issued to Francis A. Jimerson et al.  on Feb. 15, 1944 as U.S. Pat.  No.  2,342,052. 
Another patent was issued to Charles D. Hanaway on Jun. 17, 1969 as U.S. Pat.  No.  3,449,992.  Yet another U.S. Pat.  No.  3,616,488 was issued to William A. Barefield on Nov. 2, 1971.  Another was issued to Thelma G. Sigler on Apr. 4, 1978 as U.S. Pat.  No.  4,081,906 and still yet another was issued on Feb. 10, 1981 to Richard G. H. Bates as U.S. Pat.  No.  4,249,313. 
Another patent was issued to George A. Boyum et al.  on Feb. 7, 1984 as Canadian Patent No.  1,161,797.  Yet another Canadian Patent No.  1,225,307 was issued to Douglas R. Mongeon on Aug. 11, 1987.  U.S. Pat.  No.  5,012,582 was issued to Steven L. Bristol et al.  on May 7, 1991 and another patent was issued to Kenneth R. Floyd on Sep. 1, 1992. 
A pruning device comprising a hollow pole, a shaft extending longitudinally of and rotatably supported within the pole, an electric motor secured to the lower end of the pole with it""s armature shaft secured to said first shaft, a sleeve on the upper end of the pole and extending above the same, an arm extending longitudinally of one side of the sleeve and provided at its upper end with a bearing boss extending across the upper end of the sleeve, means removably securing the sleeve and arm to the pole, an arbor journaled in the bearing boss, a circular saw secured to the arbor, a stub shaft journaled in the sleeve and detachably connected to said first shaft, meshing gears fixed to the arbor and the stub shaft, an arm extending upwardly from the upper end of said first arm in the direction of the opposite side of the sleeve and to a point beyond the saw, and a shield for the saw removably secured to the upper end of said second arm and to the sleeve. 
A cutting device for a plaster cast comprising a guide adapted for introduction underneath the cast, a rotary cutter mounted for cutting into the plaster as the guide advances, a pistol grip mounted in supporting relation to the guide and the cutter, and having a motor thereon, a driving connection between the motor and the cutter, a guard for the latter and a slide mounted near the pistol grip and operatively connected to the guard for retracting and advancing the same. 
A saw for removing plaster casts, said saw including a support, a pair of saws spaced apart and rotatably mounted in said support, a shoe projecting from said support along the peripheries of said saws, a presser lever extending from said support between the saws along the peripheries thereof to clear the space between them and adapted to be positioned with its end below the upper surface of said shoe, and means for rotating said saws. 
A portable cutting tool, comprising a casing, a rotary toothed cutting disc in the casing, there being a recess in the casing to expose a segment of the cutting disc, a motor for driving the cutting disc, a grip portion on the casing extending laterally of the axis of rotation of the cutting disc and connected to an end of the motor, a grip portion on the other end of the motor, means in one grip portion and the casing for transmitting movement from the motor to the cutting disc, a guard for the cutting disc swingable into the casing and into the plane of the recess, a spring constantly tending to move the guard into the plane of the recess, a transmission member connected to the guard, and a lever on the casing adjacent said grip portion and connected to the transmission member for moving the guard out of the plane of the recess into the casing. 
A pipe or bar cutting machine of compact construction having a main frame and a secondary frame with gripping surfaces on both frames and the secondary frame guided and movable on the main frame by a screw adjustment for clamping a work piece.  An electric motor with a convenient grip and trigger slidably mounted in the main frame and driving a rotary cutter also slidably mounted in a frame to move the cutter through a work piece clamped between the gripping surfaces of the frames.  The frames are conveniently portable by reason of their attachment to the motor and the convenient hand grip on the motor. 
A cutting tool for opening the body cavity of chickens to allow easy evisceration and inspection.  The tool has a power driven, circular cutting blade which is power driven from a motor contained within a housing that is held in the hand.  A guide means extends below the edge of the cutting blade and beneath the tool housing and hand and is inserted into the chicken carcass.  There is a blade shield around the front of the blade whereby the only entrance to the blade is between the housing and the insertion member. 
A hand held electrically driven cutter assembly for removing casts from the body of a patient includes a vertically articulatable bottom plate insertable between the cast and the body surface which on the interior of the cutter assembly forms a switch in series with a trigger switch connected to the main power.  Two circular cutters, inclined relative each other, are disposed above and ahead of the bottom plate to open up a kerf therefor.  The power to the cutters is transmitted through a pulley and gear combination to be driven by an electric motor.  It is this electric motor that is series connected to the bottom plate switch and power will be applied to the cutters only upon upward urging of the cutter assembly. 
A hand held portable pruning tool having a housing enclosing a motor one or more batteries and a saw blade.  The saw blade is rotatable about an axis perpendicular to the axis of the housing.  The blade is normally protected by a telescoping guard element having a forwardly extending notch for receiving a stem or limb to be cut.  The telescoping guard element retracts into the housing in response to pressure exerted on the guard element in the direction of the stem thus bring the stem into contact with the blade and also energizing the motor. 
A tree-trimming apparatus mounted on a mobile support vehicle.  The apparatus includes a telescoping boom pivotally mounted on a pedestal.  The pedestal is pivotally mounted to a turntable which is rotatably mounted on the support vehicle.  An operator""s station is mounted on the pedestal to provide control of the apparatus.  A large diameter circular saw is mounted at the end of the boom and is powered by a high speed hydraulic motor to provide high cutting efficiency.  A fiberglass boom and electrically non-conductive hoses provide maximum safety for the operator. 
An orbital saw for use in orthopedic applications such as cutting bones including a one-piece, externally mounted saw blade that can be quickly and easily replaced by unlocking a pair of blade clamps.  The saw can be battery operated.  The battery is keyed and locked with a hand grip by a release lever to form a handle.  The battery can be unlocked and replaced when it becomes run down. 
A hand-held, battery-operated rotary blade saw useful for cutting plastic clips or straps which secure a face mask to a football helmet.  Several configurations, having differing safety shields, are disclosed.  The device is an emergency/rescue tool to quickly remove a face mask from a football helmet allowing access to the face of a football player without removal of the helmet with its concomitant risk of cervical injury. 
An elongated portable frame is provided including front and rear ends and a mid-length laterally outwardly projecting tubular handle for containing a battery pack.  The front end of the frame journals a saw blade therefrom and the saw blade is driven by an electric motor supported from the frame.  A pair of rearwardly retractable jaws are disposed on opposite sides of the forward periphery of the saw blade and are opposed by a rearwardly retractable jaw structure disposed forwardly of the forward limit positions of movement of the jaw members and an actuator for the jaw structure is disposed immediately forward of the handle for engagement and rearward displacement by the forefinger of a hand encircling the handle, whereby the jaw structure may be shifted rearwardly to initially clamp a work piece to be cut between the jaws and the jaw structure and thereafter utilized to rearwardly advance the work piece to be cut relative to the saw blade.  The rear of the frame journals rearwardly facing inner and outer conical grinding stones for outwardly and inwardly beveling, respectively, cut ends of tubular work pieces severed by the saw blade. 
While these portable cutting devices may be suitable for the purposes for which they were designed, they would not be as suitable for the purposes of the present invention, as hereinafter described. 
For example, only a limited forward cutting capability is described in such devices, with most having no forward cutting capability at all.  Furthermore, such devices no not provide a hand held rotary blade saw that can readily present an upwardly, downwardly, rightwardly and leftwardly exposed cutting blade sector, with full functional reciprocity between a right handed and left handed user.  Such capabilities are needed to optimize the utility of a hand held saw. 
A primary object of the present invention is to provide a cordless, hand-held rotary saw to replace manual hacksaws in many operations. 
Another object of the present invention is to provide a hand held rotary blade saw that can readily present an upwardly, downwardly, rightwardly and leftwardly exposed cutting blade sector, with full functional reciprocity between a right handed and left handed user. 
An additional object of the present invention is to provide a cordless, hand-held rotary saw having a cutting blade locking mechanism that prevents the blade from spinning and enables the cutting blade to be quickly and easily changed. 
A further object of the present invention is to provide a cordless, hand-held rotary saw wherein the rotary cutting blade is placed on a gear-driven plate with a central hub assembly, along with two locking posts that pass through corresponding recesses in said cutting blade. 
A yet further object of the present invention is to provide a cordless, hand-held rotary saw wherein movement of the gear-driven plate is transmitted via a drive shaft with a motor at one end and a drive gear communicating with said gear-driven plate. 
Another object of the present invention is to provide a cordless, hand-held rotary saw/grinder wherein the power source of the motor is a rechargeable battery. 
Still another object of the present invention is to provide a cordless, hand-held rotary saw having spring-loaded retractable blade guards. 
One more object of the present invention is to provide a cordless, hand-held rotary saw that is simple and easy to use. 
A further object of the present invention is to provide a cordless, hand-held rotary saw that is economical in cost to manufacture. 
Another object of the present invention is to provide a hand-held rotary saw/grinder wherein the power source of the motor is an external source. 
Further objects of the present invention will appear as the description proceeds. 
My device is a hand held rotary blade saw that has a grip that allows the user to use either thumb or finger to operate the switch without losing blade orientation function.  A motor drives a rotor shaft that is in geared communication with a blade gear to which a rotary cutting blade is attached.  Two blade guards are spring-biased into a position covering the forward cutting surfaces of the blade.  Receding forward edges on the guards allow direct contact with an object to be cut to separate the guards and expose the forwardmost cutting sector.  For other applications, dual top and bottom side pivot members are readily accessible to allow both left and right handed users to selectively expose a leftward, rightward, upward or downward cutting surface as the need arises. 
A hand held rotary blade saw powered by a power source is provided, comprising: a housing, having a front portion and a rear portion; an electric motor contained within the housing rear portion; an electromechanical switch in electronic communication with the motor and power source for activating motor functions; a rotary saw blade mounted in the housing front portion, the rotary saw blade having a rear sector circumference enclosed within the housing front portion, a first front sector circumference, and a second front sector circumference, the combined rear, first front and second front circumferences summing to a circle; a driving connection between the motor and the rotary saw blade for rotating the rotary saw blade; a first blade guard, the first blade guard being pivotable about the rotary blade from a first position covering substantially all of the blade first front sector circumference, to a second position, such that the first front sector circumference is partially exposed; a second blade guard, the second blade guard being pivotable about the rotary blade from a first position covering substantially all of the blade second front sector circumference to a second position, such that the second front sector circumference is partially exposed, the first blade guard being adapted to receive the second blade guard when either or both the first or second blade guards are pivoted, the housing front portion being adapted to receive the first blade guard when the first blade guard is pivoted, and to receive the second blade guard when the second blade guard is pivoted; and at least one guard spring contained in the housing front portion, the at least one guard spring biasing the first blade guard into the first position, and the second blade guard into the first position. 
In another embodiment, the first blade guard further comprises at least one pivot member for manual manipulation such that the first blade guard is pivoted about the rotary blade. 
In another embodiment, the first blade guard has a first and second side each side having at least one of the at least one pivot members. 
In another embodiment, at least one of the at least one pivot members protrudes from the first blade guard. 
In another embodiment, at least one of the at least one pivot members recedes into the first blade guard. 
In another embodiment, the first blade guard has an edge proximate the blade circumference and at least one of the at least one pivot members is positioned on the edge. 
In another embodiment, the first blade guard has a first side, a second side, and an edge proximate the blade circumference, and at least one of the at least one pivot members extends continuously from the first side, around the edge and to the second side. 
In another embodiment, the second blade guard further comprises at least one pivot member for manual manipulation such that the second blade guard is pivoted about the rotary blade. 
In another embodiment, the second blade guard has a first and second side each side having at least one of the at least one pivot members. 
In another embodiment, at least one of the at least one pivot members protrudes from the second blade guard. 
In another embodiment, at least one of the at least one pivot members recedes into the second blade guard. 
In another embodiment, the second blade guard has an edge proximate the blade circumference and at least one of the at least one pivot members is positioned on the edge. 
In another embodiment, the second blade guard has a first side, a second side, and an edge proximate the blade circumference, and at least one of the at least one pivot members extends continuously from the first side, around the edge and to the second side. 
In another embodiment, the first blade guard further comprises at least one pivot member for manual manipulation such that the first blade guard is pivoted about the rotary blade, and the second blade guard further comprises at least one pivot member for manual manipulation such that the second blade guard is pivoted about the rotary blade. 
In another embodiment, the first blade guard has a first and second side each side having at least one of the at least one first blade guard pivot members, and the second blade guard has a first and second side each side having at least one of the at least one second blade guard pivot members. 
In another embodiment, at least one of the at least one first blade guard pivot members protrudes from the first blade guard, and at least one of the at least one second blade guard pivot members protrudes from the second blade guard. 
In another embodiment, at least one of the at least one first blade guard pivot members recedes into the first blade guard, and at least one of the at least one second blade guard pivot members recedes into the second blade guard. 
In another embodiment, the first blade guard has an edge proximate the blade circumference and at least one of the at least one first blade guard pivot members is positioned on the first blade guard edge, and the second blade guard has an edge proximate the blade circumference and at least one of the at least one second blade guard pivot members is positioned on the second blade guard edge. 
In another embodiment, the first blade guard has a first side, a second side, and an edge proximate the blade circumference, and at least one of the at least one first blade guard pivot members extends continuously from the first blade guard first side, around the edge and to the second side, and the second blade guard has a first side, a second side, and an edge proximate the blade circumference, and at least one of the at least one second blade guard pivot members extends continuously from the second blade guard first side, around the edge and to the second side. 
In another embodiment, the power source is a battery. 
In another embodiment, the battery is contained in the housing rear portion, the battery being in electronic communication with the motor. 
In another embodiment, the housing rear portion is adapted to receive a power cord for delivering power to the motor. 
In another embodiment, the at least one blade guard spring comprises a first blade guard spring biasing the first blade guard and a second blade guard spring biasing the second blade guard. 
In another embodiment, the driving connection further comprises: a post positioned within the housing front portion; a blade gear, the blade gear being attached to the rotary blade and mounted on the post for rotation; and a rotor shaft extending out of the motor and into the housing front portion, the rotor shaft being in geared communication with the blade gear such that the blade gear is rotated as the rotor shaft is rotated. 
In another embodiment, the blade gear has at least two locking posts, the rotary blade having at least two apertures for closely receiving the locking posts, thus preventing slip as the rotary blade rotates with the blade gear on the post. 
In another embodiment, the housing front portion has a removable portion, allowing removal of the blade from the post. 
In another embodiment, the device further comprises a hub assembly having a first and second portion, the blade and the blade gear each having a centrally disposed hole for closely receiving the hub assembly first portion, the blade being attached to the blade gear by the joinder of the hub assembly second portion to the first portion so received. 
In another embodiment, the blade gear has at least one protrusion and the blade has at least one hole aligned with said protrusion when the blade is attached to the blade gear. 
In another embodiment, the first and second blade guards each have a forward edge, the forward edges being substantially aligned and proximate when the first and second blade guards are both in the first position, the first and second blade guard forward edges each having a receding edge such that the forward edge receding edges form a notch. 
In another embodiment, the switch has a member positioned for being pressed by the thumb while the housing rear portion is being hand held. 
In another embodiment, the member must be pressed down and then forward to activate the motor. 
In another embodiment, the device further comprises a carrying case, the case being sized to receive the saw, the case having a zippered lid, at least one belt loop, a hinged flap, the flap having a threaded protrusion for receiving additional blades, and a nut for coupling with the threaded protrusion on the flap. 
In another embodiment, the device further comprises a saw carrying device for carrying the saw on a belt, the device having a holster, a belt clasp for attaching the holster to the belt, and a hook and loop fastener having a first portion on the holster and a second portion on the saw. 
In another embodiment, the device further comprises a charger, the power source being a battery contained within the housing rear portion, the charger having a first receptacle, the saw housing rear portion being adapted to be received by the first charger receptacle such that the battery is charged while remaining in housing rear portion, the charger having a second receptacle for receiving the battery, the battery being charged when so received. 
In another embodiment, the charger is powered by both an AC power cord and an automobile charger plug cord. 
In another embodiment, the power source is an external battery, the housing rear portion being adapted to electronically mate with the external battery. 
In another embodiment, the device further comprises an AC power cord, the housing rear portion being electronically mated with the cord such that the motor is powered when the cord is plugged into an AC receptacle. 
A hand held rotary blade saw is provided, comprising: a housing, having a front portion and a rear portion; a rotary saw blade mounted in the housing rear portion on the post, the rotary saw blade having a rear sector circumference enclosed within the housing front portion, a first front sector circumference, and a second front sector circumference, the combined rear, first front and second front circumferences summing to a circle; means for electro-mechanically rotating the rotary saw blade; means for alternately covering and partially exposing the blade first front sector circumference, said means being biased to the covering position; and means for alternately covering and partially exposing the blade second front sector circumference, said means being biased to the covering position. 
In another embodiment, the means for alternately covering and partially exposing the blade first front sector further comprises means for manually manipulating said means from both above and below the bottom side of the saw. 
In another embodiment, the means for alternately covering and partially exposing the blade second front sector further comprises means for manually manipulating said means from both above and below the bottom side of the saw. 
In another embodiment, the means for electro-mechanically rotating the rotary saw blade has a motor, a power source for powering the motor, an electromechanical switch for activating the motor functions, a rotor shaft rotated by the motor, a drive gear rotated by the rotor shaft, and a blade gear rotated by the drive gear and attached to the rotary blade. 
In another embodiment, the power source is a battery. 
In another embodiment, the device further comprises means for charging the battery. 
In another embodiment, the means for charging the battery further comprises means for charging the battery while the battery remains in the housing rear portion. 
In another embodiment, the device further comprises means for enclosing and transporting the saw. 
In another embodiment, the device further comprises means for holstering and transporting the saw. 
A hand held rotary blade saw is provided, comprising: a housing, having a front portion and a rear portion; an electric motor contained within the housing rear portion; a power source for powering the motor; an electromechanical switch in electronic communication with the motor and power source for activating motor functions; a rotary saw blade mounted in the housing front portion, the rotary saw blade having a rear sector circumference enclosed within the housing front portion, a first front sector circumference, and a second front sector circumference, the combined rear, first front and second front circumferences summing to a circle; a driving connection between the motor and the rotary saw blade for rotating the rotary saw blade; a first blade guard, the first blade guard being pivotable about the rotary blade from a first position covering substantially all of the blade first front sector circumference, to a second position, such that the first front sector circumference is partially exposed; a second blade guard, the second blade guard being pivotable about the rotary blade from a first position covering substantially all of the blade second front sector circumference to a second position, such that the second front sector circumference is partially exposed, the first blade guard being adapted to receive the second blade guard when either or both the first or second blade guards are pivoted, the housing front portion being adapted to receive the first blade guard when the first blade guard is pivoted, and to receive the second blade guard when the second blade guard is pivoted; and at least one guard spring contained in the housing front portion, the at least one guard spring biasing the first blade guard into the first position, and the second blade guard into the first position. 
To the accomplishments of the above and related objects, this invention may be embodied in the form illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and that changes may be made in the specific construction illustrated and described in the appended claims.